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Zhao K, Chen L, Xie Y, Ren N, Li J, Zhai X, Zheng S, Liu K, Wang C, Qiu Q, Peng X, Wang W, Liu J, Che Q, Fan J, Hu H, Liu M. m6A/HOXA10-AS/ITGA6 axis aggravates oxidative resistance and malignant progression of laryngeal squamous cell carcinoma through regulating Notch and Keap1/Nrf2 pathways. Cancer Lett 2024; 587:216735. [PMID: 38369001 DOI: 10.1016/j.canlet.2024.216735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/05/2024] [Accepted: 02/16/2024] [Indexed: 02/20/2024]
Abstract
As the second most prevalent malignant tumor of head and neck, laryngeal squamous cell carcinoma (LSCC) imposes a substantial health burden on patients worldwide. Within recent years, resistance to oxidative stress and N6-methyladenosine (m6A) of RNA have been proved to be significantly involved in tumorigenesis. In current study, we investigated the oncogenic role of m6A modified long non coding RNAs (lncRNAs), specifically HOXA10-AS, and its downstream signaling pathway in the regulation of oxidative resistance in LSCC. Bioinformatics analysis revealed that heightened expression of HOXA10-AS was associated with the poor prognosis in LSCC patients, and N (6)-Methyladenosine (m6A) methyltransferase-like 3 (METTL3) was identified as a factor in promoting m6A modification of HOXA10-AS and further intensify its RNA stability. Mechanistically, HOXA10-AS was found to play as a competitive endogenous RNA (ceRNA) by sequestering miR-29 b-3p and preventing its downregulation of Integrin subunit alpha 6 (ITGA6), ultimately enhancing the oxidative resistance of tumor cells and promoting the malignant progression of LSCC. Furthermore, our research elucidated the mechanism by which ITGA6 accelerates Keap1 proteasomal degradation via enhancing TRIM25 expression, leading to increased Nrf2 stability and exacerbating its aberrant activation. Additionally, we demonstrated that ITGA6 enhances γ-secretase-mediated Notch signaling activation, ultimately promoting RBPJ-induced TRIM25 transcription. The current study provides the evidence supporting the effect of m6A modified HOXA10-AS and its downstream miR-29 b-3p/ITGA6 axis on regulating oxidative resistance and malignant progression in LSCC through the Notch and Keap1/Nrf2 pathways, and proposed that targeting this axis holds promise as a potential therapeutic approach for treating LSCC.
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Affiliation(s)
- Kai Zhao
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Liwei Chen
- Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Yingli Xie
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China; Medical School of Chinese PLA, Beijing, 100853, PR China
| | - Nan Ren
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Jianhui Li
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Xingyou Zhai
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Shikang Zheng
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Kun Liu
- Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing 100853, PR China
| | - Cheng Wang
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Qibing Qiu
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, PR China
| | - Xin Peng
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Wenjia Wang
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China; Medical School of Chinese PLA, Beijing, 100853, PR China
| | - Jinjing Liu
- Medical School of Chinese PLA, Beijing, 100853, PR China
| | - Qin Che
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Junda Fan
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China
| | - Hai Hu
- Department of Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, PR China; Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, PR China.
| | - Mingbo Liu
- Department of Otolaryngology Head and Neck Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, 572013, PR China; Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing 100853, PR China; The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, PR China.
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Liu Y, Li Z. Vaginal pH value can affect the susceptibility to human papillomavirus infection. BMC Infect Dis 2024; 24:176. [PMID: 38331746 PMCID: PMC10854022 DOI: 10.1186/s12879-024-09074-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 01/29/2024] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND Cervical cancer is the fourth most common cancer among women, with persistent high-risk human papillomavirus (HPV) infection being responsible for its progression. In healthy, pre-menopausal women, the vaginal pH value is maintained at 3.8-4.5, but various factors can affect it. Previous studies have suggested the relationship between vaginal pH value and HPV infection. In this study, we aimed to explore the relationship between vaginal pH and susceptibility of HPV infection. METHODS In our study, we retrospectively collected medical information from women who underwent leukorrhea examination at our hospital. We excluded women with infectious diseases or cancer, those who were pregnant or within 6 months post-delivery, and those without HPV test results within 6 months. The association between percentage of HPV infection and vaginal pH value was analyzed. Furthermore, we prepared HPV pseudovirus (PsVs) by co-transfecting structure plasmids and report plasmids in 293FT cells. In vitro, we changed the pH value of cell culture medium to investigate its influence on HPV PsVs infection. In vivo, we changed mouse's vaginal pH value to investigate its influence on HPV PsVs infection. RESULTS Our retrospective study included 3115 women aged 20-78, including 2531 women with HPV negative and 584 women with HPV positive. The percentages of both HPV infection and high-risk HPV infection were higher in women with a vaginal pH value ≥5.0 compared to those with a pH value < 5.0. In vitro, HPV PsVs infection rate was higher in cell culture medium of higher pH value, dominantly due to the influence of pH value on the stage of HPV PsVs adhering to cell surface. Neither of the cell surface HPV receptors Syndecan-1 nor integrin α6 was found to be changed obviously in different pH values. In vivo, more HPV PsVs were adhered to the mouse's vaginal epithelial cells with the increase of the vaginal pH value. CONCLUSIONS Our study suggests a possible association between vaginal pH value and HPV infection. The pH value can influence the susceptibility of HPV PsVs infection by affecting the adhering of HPV PsVs to cells in vivo and in vitro. Additionally, the cell surface HPV receptors Syndecan-1 and Integrin α6 do not seem to be affected by pH value, and the specific mechanism needs to be further explored.
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Affiliation(s)
- Yinxia Liu
- Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, No. 20 Section 3, Renmin South Road, Chengdu, Sichuan, 610041, People's Republic of China
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Zhengyu Li
- Department of Gynecology and Obstetrics, West China Second University Hospital, Sichuan University, No. 20 Section 3, Renmin South Road, Chengdu, Sichuan, 610041, People's Republic of China.
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, People's Republic of China.
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Tran ANT, Kim HY, Oh SY, Kim HS. CD49f and CD146: A Possible Crosstalk Modulates Adipogenic Differentiation Potential of Mesenchymal Stem Cells. Cells 2023; 13:55. [PMID: 38201259 PMCID: PMC10778538 DOI: 10.3390/cells13010055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/07/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND The lack of appropriate mesenchymal stem cells (MSCs) selection methods has given the challenges for standardized harvesting, processing, and phenotyping procedures of MSCs. Genetic engineering coupled with high-throughput proteomic studies of MSC surface markers arises as a promising strategy to identify stem cell-specific markers. However, the technical limitations are the key factors making it less suitable to provide an appropriate starting material for the screening platform. A more accurate, easily accessible approach is required to solve the issues. METHODS This study established a high-throughput screening strategy with forward versus side scatter gating to identify the adipogenesis-associated markers of bone marrow-derived MSCs (BMSCs) and tonsil-derived MSCs (TMSCs). We classified the MSC-derived adipogenic differentiated cells into two clusters: lipid-rich cells as side scatter (SSC)-high population and lipid-poor cells as SSC-low population. By screening the expression of 242 cell surface proteins, we identified the surface markers which exclusively found in lipid-rich subpopulation as the specific markers for BMSCs and TMSCs. RESULTS High-throughput screening of the expression of 242 cell surface proteins indicated that CD49f and CD146 were specific for BMSCs and TMSCs. Subsequent immunostaining confirmed the consistent specific expression of CD49f and CD146 and in BMSCs and TMSCs. Enrichment of MSCs by CD49f and CD146 surface markers demonstrated that the simultaneous expression of CD49f and CD146 is required for adipogenesis and osteogenesis of mesenchymal stem cells. Furthermore, the fate decision of MSCs from different sources is regulated by distinct responses of cells to differentiation stimulations despite sharing a common CD49f+CD146+ immunophenotype. CONCLUSIONS We established an accurate, robust, transgene-free method for screening adipogenesis associated cell surface proteins. This provided a valuable tool to investigate MSC-specific markers. Additionally, we showed a possible crosstalk between CD49f and CD146 modulates the adipogenesis of MSCs.
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Affiliation(s)
- An Nguyen-Thuy Tran
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea; (A.N.-T.T.); (H.Y.K.)
- Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Ha Yeong Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea; (A.N.-T.T.); (H.Y.K.)
| | - Se-Young Oh
- Department of Convergence Medicine, Ewha Womans University Mokdong Hospital, Ewha Womans University, Seoul 07985, Republic of Korea;
| | - Han Su Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Ewha Womans University, Seoul 07985, Republic of Korea; (A.N.-T.T.); (H.Y.K.)
- Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
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Mukhopadhyay D, Goel HL, Xiong C, Goel S, Kumar A, Li R, Zhu LJ, Clark JL, Brehm MA, Mercurio AM. The calcium channel TRPC6 promotes chemotherapy-induced persistence by regulating integrin α6 mRNA splicing. Cell Rep 2023; 42:113347. [PMID: 37910503 PMCID: PMC10872598 DOI: 10.1016/j.celrep.2023.113347] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/06/2023] [Accepted: 10/10/2023] [Indexed: 11/03/2023] Open
Abstract
Understanding the cell biological mechanisms that enable tumor cells to persist after therapy is necessary to improve the treatment of recurrent disease. Here, we demonstrate that transient receptor potential channel 6 (TRPC6), a channel that mediates calcium entry, contributes to the properties of breast cancer stem cells, including resistance to chemotherapy, and that tumor cells that persist after therapy are dependent on TRPC6. The mechanism involves the ability of TRPC6 to regulate integrin α6 mRNA splicing. Specifically, TRPC6-mediated calcium entry represses the epithelial splicing factor ESRP1 (epithelial splicing regulatory protein 1), which enables expression of the integrin α6B splice variant. TRPC6 and α6B function in tandem to facilitate stemness and persistence by activating TAZ and, consequently, repressing Myc. Therapeutic inhibition of TRPC6 sensitizes triple-negative breast cancer (TNBC) cells and tumors to chemotherapy by targeting the splicing of α6 integrin mRNA and inducing Myc. These data reveal a Ca2+-dependent mechanism of chemotherapy-induced persistence, which is amenable to therapy, that involves integrin mRNA splicing.
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Affiliation(s)
- Dimpi Mukhopadhyay
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Hira Lal Goel
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Choua Xiong
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Shivam Goel
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Ayush Kumar
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Rui Li
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Lihua Julie Zhu
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Jennifer L Clark
- Department of Pathology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Michael A Brehm
- Department of Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Arthur M Mercurio
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA.
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Ryu S, Yoon SH, Song J, Choi Y, Lee S, Baek M, Lee HB, Jeon SY, Jon S, Lee D, Kim HS, Han W. Impact of media compositions and culture systems on the immunophenotypes of patient-derived breast cancer cells. BMC Cancer 2023; 23:831. [PMID: 37670250 PMCID: PMC10481485 DOI: 10.1186/s12885-023-11185-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/17/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Heterogeneous tumor cells are thought to be a significant factor in the failure of endocrine therapy in estrogen receptor-positive (ER+) cancers. Culturing patient-derived breast cancer cells (PDBCCs) provides an invaluable tool in pre-clinical and translational research for the heterogeneity of cancer cells. This study aimed to investigate the effects of different media components and culture methods on the BCSC-associated immunophenotypes and gene expression in ER + PDBCCs. METHODS Ten patients with ER + breast cancer were employed in this study, six of whom had neoadjuvant chemotherapy and four of whom did not. PDBCCs were isolated by enzymatic methods using collagen I and hyaluronidase. PDBCCs were grown as monolayers in mediums with different compositions and as multicellular spheroid in a suspended condition. Collagen I-coated plate and ultralow attachment plate coated with polymer-X were used for monolayer and spheroid culture. Flow cytometry, immunofluorescent staining, RT-PCR, and RNA-sequencing were employed to examine the immunophenotype and genetic profile of PDBCCs. RESULTS More than 95% of PDBCCs sustain EpCAM high/+/fibroblast marker- phenotypes in monolayer conditions by subculturing 3-4 times. A83-01 removal induced senescent cells with high β-galactosidase activity. PDBCCs grown as monolayers were characterized by the majority of cells having an EpCAM+/CD49f + phenotype. Compared to full media in monolayer culture, EGF removal increased EpCAM+/CD49f - phenotype (13.8-fold, p = 0.028), whereas R-spondin removal reduced it (0.8-fold, p = 0.02). A83-01 removal increased EpCAM+/CD24 + phenotype (1.82-fold, p = 0.023) and decreased EpCAM low/-/CD44+/CD24- phenotype (0.45-fold, p = 0.026). Compared to monolayer, spheroid resulted in a significant increase in the population with EpCAM-/CD49+ (14.6-fold, p = 0.006) and EpCAM low/-/CD44+/CD24- phenotypes (4.16-fold, p = 0.022) and ALDH high activity (9.66-fold, p = 0.037). ALDH1A and EMT-related genes were upregulated. In RNA-sequencing analysis between spheroids and monolayers, a total of 561 differentially expressed genes (2-fold change, p < 0.05) were enriched in 27 KEGG pathways including signaling pathways regulating pluripotency of stem cells. In a recurrence-free survival analysis based on the Kaplan-Meier Plotter database of the up-and down-regulated genes identified in spheroids, 15 up-, and 14 down-regulated genes were associated with poor prognosis of breast cancer patients. CONCLUSION The media composition and spheroid culture method change in the BCSCs and EMT markers of PDBCCs, implying the importance of defining the media composition and culture method for studying PDBCCs in vitro.
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Affiliation(s)
- Seungyeon Ryu
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
- Interdisciplinary Programs in Cancer Biology Major, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
- Integrated Major in Innovative Medical Science, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
| | - So-Hyun Yoon
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
- Interdisciplinary Programs in Cancer Biology Major, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
- Integrated Major in Innovative Medical Science, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
| | - Junhyuk Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291, Daehak-ro, Yuseong-gu, 34141, Daejeon, Republic of Korea
| | - Yoonjung Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291, Daehak-ro, Yuseong-gu, 34141, Daejeon, Republic of Korea
| | - Sangeun Lee
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Interdisciplinary Programs in Cancer Biology Major, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
| | - Moonjou Baek
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Interdisciplinary Programs in Cancer Biology Major, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
| | - Han-Byoel Lee
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea
- Department of Surgery, Seoul National University College of Medicine, 103, Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Sook Young Jeon
- Department of Surgery, Kangnam Sacred Heart Hospital, 1 Shingil-ro, Youngdeungpo-ku, 07441, Seoul, Republic of Korea
| | - Sangyong Jon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291, Daehak-ro, Yuseong-gu, 34141, Daejeon, Republic of Korea
| | - Daeyoup Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291, Daehak-ro, Yuseong-gu, 34141, Daejeon, Republic of Korea
| | - Hoe Suk Kim
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea.
- Department of Pharmaceutical Sciences, College of Pharmacy & Allied Health Professions, South Dakota State University, SAV# 255, Box2202C, Brookings, SD 57007, USA.
| | - Wonshik Han
- Cancer Research Institute, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea.
- Interdisciplinary Programs in Cancer Biology Major, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea.
- Integrated Major in Innovative Medical Science, Seoul National University Graduate School, 103, Daehak-ro, Jongno-gu, 03080, Seoul, Republic of Korea.
- Department of Surgery, Seoul National University College of Medicine, 103, Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Genomic Medicine Institute, Medical Research Center, Seoul National University, 103, Daehak- ro, Jongno-gu, 03080, Seoul, Republic of Korea.
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Chen L, Fu H, He H, Lou K, Li Q, Ye J, Feng G, Yu C. Automated Synthesis and Preclinical Evaluation of Optimized Integrin α6-Targeted Positron Emission Tomography Imaging of Pancreatic Cancer. Mol Pharm 2023; 20:4277-4284. [PMID: 37463487 DOI: 10.1021/acs.molpharmaceut.3c00321] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Integrin α6 has been considered a promising biomarker, is overexpressed in many tumors, and plays a vital role in tumor formation, recurrence, and metastasis. In this study, we identified a novel high-affinity integrin α6-targeted peptide named RD2 (Arg-Trp-Tyr-Asp-PEG4)2-Lys-Lys and developed a 18F-radiolabeled peptide tracer ([18F]-AlF-NOTA-RD2) and evaluated its potential application in positron emission tomography (PET) imaging of pancreatic cancer. [18F]-AlF-NOTA-RD2 was produced using GMP (Good Manufacturing Practice of Medical Products)-compliant automatic radiosynthesis on a single GE FASTLab2 cassette-type synthesis module. The stability of [18F]-AlF-NOTA-RD2 was analyzed in phosphate-buffered saline (PBS) and fetal bovine serum (FBS). The cell uptake assay of the tracer was assessed using PANC-1 cells. In addition, small-animal PET imaging and biodistribution studies of [18F]-AlF-NOTA-RD2 were performed in pancreatic cancer subcutaneous tumor-bearing mice. The PET tracer [18F]-AlF-NOTA-RD2 was obtained with a radiochemical yield of 23.7 ± 4.7%, radiochemical purity of >99%, and molar activity of 165.7 ± 59.1 GBq/μmol. [18F]-AlF-NOTA-RD2 exhibited good in vitro stability in PBS and FBS. LogP octanol water value for the tracer was -2.28 ± 0.05 (n = 3). The binding affinity of RD2 to the integrin α6 protein (Kd = 0.13 ± 3.65 μM, n = 3) was significantly higher than that of the RWY (CRWYDENAC) (Kd = 6.97 ± 1.44 μM, n = 3). Small-animal PET imaging and biodistribution also revealed that [18F]-AlF-NOTA-RD2 displayed rapid and good tumor uptake and lower liver background uptake in PANC-1 tumor-bearing mice. [18F]-AlF-NOTA-RD2 showed significant radioactivity accumulation in tumors and was successfully blocked by NOTA-RD2. Compared with [18F]-FDG, [18F]-AlF-NOTA-RD2 PET imaging and biodistribution studies in PANC-1 xenograft tumor-bearing mice confirmed a good tumor-to-muscle ratio (8.69 ± 2.03 vs 1.41 ± 0.23, respectively) at 0.5 h and (2.99 ± 3.02 vs 1.43 ± 0.17, respectively) at 1 h post injection. Autoradiography of human pancreatic cancer tumor tissues further confirmed high accumulation of [18F]-AlF-NOTA-RD2. In summary, we developed an optimized integrin α6-targeted imaging tracer and obtained high radioactivity products with a cassette-type synthesis module; moreover, the tracer exhibited good binding affinity with integrin α6 and good target specificity for PANC-1 cells in xenograft pancreatic tumor-bearing mice, demonstrating its promising application as a noninvasive PET radiotracer of integrin α6 expression in pancreatic cancer.
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Affiliation(s)
- Liping Chen
- Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi 214062, P.R. China
| | - Haitian Fu
- Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi 214062, P.R. China
| | - Huihui He
- Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi 214062, P.R. China
| | - Kequan Lou
- Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi 214062, P.R. China
| | - Qingbo Li
- Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi 214062, P.R. China
| | - Jiacong Ye
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou 510060, P.R. China
| | - Guokai Feng
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng Road East, Guangzhou 510060, P.R. China
| | - Chunjing Yu
- Department of Nuclear Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi 214062, P.R. China
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Mestrallet G, Carosella ED, Martin MT, Rouas-Freiss N, Fortunel NO, LeMaoult J. Immunosuppressive Properties of Epidermal Keratinocytes Differ According to Their Immaturity Status. Front Immunol 2022; 13:786859. [PMID: 35222373 PMCID: PMC8878806 DOI: 10.3389/fimmu.2022.786859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/14/2022] [Indexed: 12/04/2022] Open
Abstract
Preservation of a functional keratinocyte stem cell pool is essential to ensure the long-term maintenance of epidermis integrity, through continuous physiological renewal and regeneration in case of injury. Protecting stem cells from inflammation and immune reactions is thus a critical issue that needs to be explored. Here, we show that the immature CD49fhigh precursor cell fraction from interfollicular epidermis keratinocytes, comprising stem cells and progenitors, is able to inhibit CD4+ T-cell proliferation. Of note, both the stem cell-enriched CD49fhigh/EGFRlow subpopulation and the less immature CD49fhigh/EGFRhigh progenitors ensure this effect. Moreover, we show that HLA-G and PD-L1 immune checkpoints are overexpressed in CD49fhigh precursors, as compared to CD49flow differentiated keratinocytes. This potency may limit immune reactions against immature precursors including stem cells, and protect them from exacerbated inflammation. Further exploring this correlation between immuno-modulation and immaturity may open perspectives in allogenic cell therapies.
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Affiliation(s)
- Guillaume Mestrallet
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DRF, Francois Jacob Institute of Biology, Laboratory of Genomics and Radiobiology of Keratinopoiesis, Institute of Cellular and Molecular Radiobiology, Evry, France
- Université Paris-Saclay, Saint-Aubin, France
| | - Edgardo D. Carosella
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DRF, Francois Jacob Institute of Biology, Hemato-Immunology Research Department, Saint-Louis Hospital, Paris, France
- U976 HIPI Unit, IRSL, Université Paris, Paris, France
| | - Michele T. Martin
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DRF, Francois Jacob Institute of Biology, Laboratory of Genomics and Radiobiology of Keratinopoiesis, Institute of Cellular and Molecular Radiobiology, Evry, France
- Université Paris-Saclay, Saint-Aubin, France
| | - Nathalie Rouas-Freiss
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DRF, Francois Jacob Institute of Biology, Hemato-Immunology Research Department, Saint-Louis Hospital, Paris, France
- U976 HIPI Unit, IRSL, Université Paris, Paris, France
| | - Nicolas O. Fortunel
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DRF, Francois Jacob Institute of Biology, Laboratory of Genomics and Radiobiology of Keratinopoiesis, Institute of Cellular and Molecular Radiobiology, Evry, France
- Université Paris-Saclay, Saint-Aubin, France
- *Correspondence: Joel LeMaoult, ; Nicolas O. Fortunel,
| | - Joel LeMaoult
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), DRF, Francois Jacob Institute of Biology, Hemato-Immunology Research Department, Saint-Louis Hospital, Paris, France
- U976 HIPI Unit, IRSL, Université Paris, Paris, France
- *Correspondence: Joel LeMaoult, ; Nicolas O. Fortunel,
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8
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Sun C, Xu B, Wang L, Su Y. LncRNA DRAIC regulates cell proliferation and migration by affecting the miR-34a-5p/ITGA6 signal axis in Hirschsprung's disease. Ups J Med Sci 2021; 126:7895. [PMID: 34471485 PMCID: PMC8383934 DOI: 10.48101/ujms.v126.7895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/07/2021] [Accepted: 07/12/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Hirschsprung's disease (HSCR) is a common defect in newborns, and studies have revealed that long non-coding RNA (lncRNA) is involved in the progression of HSCR. This research study aims to investigate the mechanism of downregulated RNA in cancer (DRAIC) on cell proliferation and migration in HSCR. METHODS Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect the expression of DRAIC in HSCR bowel stenosis tissues and normal colon tissues. Cell-counting kit-8 (CCK-8) and Transwell assays were employed to explore whether cellular functions change after overexpression or knockdown of the DRAIC in SH-SY5Y cells and human 293T cells. Protein expression levels were determined by Western blot analysis. RNA pull-down and dual-luciferase reporter assays were used to confirm the competitive relationship of DRAIC and integrin subunit alpha 6 (ITGA6) through their association with miR-34a-5p. RESULTS The lncRNA DRAIC was significantly increased in colon tissue from HSCR patients. The overexpression of DRAIC inhibited SH-SY5Y cell and human 293T cell proliferation and migration. Knockdown of DRAIC, however, promoted cell proliferation and migration. The RNA pull-down and dual-luciferase reporter assays have proven the competitive relationship between DRAIC and ITGA6 through their association with miR-34a-5p. Further rescue experiments have confirmed that DRAIC regulates cell proliferation and migration by affecting the miR-34a-5p/ITGA6 signal axis in HSCR. CONCLUSION DRAIC promoted cell proliferation and migration by regulating the miR-34a-5p/ITGA6 signal axis in HSCR.
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Affiliation(s)
- Chuancheng Sun
- Pediatric Surgery, The First Affiliated Hospital of China University of Science and Technology (Anhui Provincial Hospital), Hefei, Anhui, China
| | - Bing Xu
- Pediatric Surgery, The First Affiliated Hospital of China University of Science and Technology (Anhui Provincial Hospital), Hefei, Anhui, China
| | - Liang Wang
- Pediatric Surgery, The First Affiliated Hospital of China University of Science and Technology (Anhui Provincial Hospital), Hefei, Anhui, China
| | - Yilin Su
- Pediatric Surgery, The First Affiliated Hospital of China University of Science and Technology (Anhui Provincial Hospital), Hefei, Anhui, China
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9
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Choi YJ, Song H, Kwon DN, Cho SK, Kang SJ, Yoe SM, Kim HC, Lee HT, Park C, Kim JH. Significant IgG-immunoreactivity of the spermatogonia of the germ cell-depleted testis after busulfan treatment. Anim Reprod Sci 2006; 91:317-35. [PMID: 15941629 DOI: 10.1016/j.anireprosci.2005.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Accepted: 04/15/2005] [Indexed: 12/22/2022]
Abstract
Busulfan kills spermatogonia with the exception of a few that are attached to the basal membrane of the seminiferous epithelium. In mice, these remaining spermatogonia reacted strongly to a goat anti-mouse IgG antibody. Spermatogonia in untreated testes rarely showed the same reactivity. Testicular IgG levels are normally minimal but increase markedly, 4 weeks after busulfan treatment before peaking at week 6. Laser scanning cytometry analysis of control and busulfan-treated testicular cells showed busulfan treatment increased the frequency of cells that were positive for not only IgG (from 0.67+/-0.29 to 16.5+/-3.8%) but also for alpha6-integrin, beta1-integrin, GFR(-1 and/or Ret. Thus, an enrichment in putative male stem cells correlates with appearance of IgG expression. Confocal microscopy revealed busulfan-treated cells contained both IgG and GFRalpha-1, and that the initial surface IgG became intracellular in the weeks following busulfan treatment. The basement membranes of the seminiferous tubules were compromised by busulfan treatment as the mRNA expression profiles of various adhesion molecules in the basement membranes were altered and electron microscopy revealed severe damage. Serum IgG levels increased in a manner corresponding with the increase in testicular IgG levels. Thus, it appears that in the busulfan-treated testis, small breaches of the blood-testis barrier leak IgG that is then taken up by a significant number of spermatogonia. When the busulfan-resistant germ cells were transferred into recipient germ cell-depleted testes, they settled and repopulated the recipient testes. Thus, the IgG-bearing cells observed after busulfan treatment may be putative spermatogonial stem cells.
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Affiliation(s)
- Yun-Jung Choi
- Department of Dairy Science, Division of Animal Science and Technology, College of Agriculture and Life Science, Gyeongsang National University, Jinju, GyeongNam 660-701, Republic of Korea
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10
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Quondamatteo F, Kempkensteffen C, Miosge N, Sonnenberg A, Herken R. Ultrastructural localization of integrin subunits alpha3 and alpha6 in capillarized sinusoids of the human cirrhotic liver. Histol Histopathol 2004; 19:799-806. [PMID: 15168343 DOI: 10.14670/hh-19.799] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Normal liver sinusoids are not lined by a basement membrane (BM). In contrast, in the course of development of liver cirrhosis, a structured BM is formed de novo in the space of Disse. This BM contributes to the inhibition of the metabolic function of the liver but the pathogenic background of the formation of this perisinusoidal BM is still unclear. Integrins of the beta1-class are generally essential for BM stability and some of them (such as alpha2beta1, alpha3beta1 and alpha6beta1) appear de novo in the perisinusoidal space of the cirrhotic liver. Their cellular distribution in capillarized sinusoids as well as the correlation between their cellular distribution and the formation of the microvascular BM in the cirrhotic liver has not been shown at the ultrastructural level. In the present work we aimed to clarify this issue. We focused on integrins alpha3beta1 and alpha6beta1 and localised them ultrastructurally in human cirrhotic liver microvessels using postembedding immunogold which allows the ultrastructural localization of antigens with high resolution in the tissue. The newly formed basement membrane of capillarized sinusoids was visualized by means of fixation with addition of tannic acid, which enables the visualization of structures of the extracellular matrix with the highest resolution. Also, we carried out laminin detection using postembedding immunogold. Our results show that both alpha3beta1 and alpha6beta1 are expressed on the surface of both hepatocytes and endothelial cells, i.e. on both sides of the newly formed basement membrane. This latter shows zones of higher density both in close proximity to the endothelial and to the hepatocytic surfaces which resemble laminae densae. We propose that hepatocytes and endothelial cells may, therefore, by expressing such integrins, contribute to the formation of this pathological BM in the microvessels of the human cirrhotic liver. On stellate cells, which are major producers of BM components, both integrins alpha3beta1 and alpha6beta1 were also localized.
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Affiliation(s)
- F Quondamatteo
- Department of Histology, University of Goettingen, Goettingen, Germany.
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11
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Sami N, Bhol KC, Ahmed AR. Treatment of oral pemphigoid with intravenous immunoglobulin as monotherapy. Long-term follow-up: influence of treatment on antibody titres to human alpha6 integrin. Clin Exp Immunol 2002; 129:533-40. [PMID: 12197896 PMCID: PMC1906475 DOI: 10.1046/j.1365-2249.2002.01942.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2002] [Indexed: 11/20/2022] Open
Abstract
SUMMARY Oral pemphigoid (OP) is a chronic autoimmune disease, involving the oral cavity, characterized by a homogenous linear deposition of immunoglobulins, complement, or both along the basement membrane zone (BMZ) and a subepithelial blister formation. The alpha6/beta4 heterodimer is an integrin family of adhesion receptors, which mediates basal cell to matrix interactions. Recent evidence suggests a pathophysiologic role for antibodies against human alpha6 integrin in blister formation in OP, in organ culture studies. Fifty percent of OP patients have been reported to experience disease progression to involve other mucosal tissues, including the eye and larynx. To prevent this extension of disease, systemic therapy with systemic corticosteroids, dapsone, and immunosuppressive agents has been recommended. The use of intravenous immunoglobulin (IVIg) in the treatment of pemphigoid has been recently described. In this study, we present the use of IVIg, in a group of seven patients, with severe OP, in whom systemic conventional treatment was contraindicated. To determine the influence of treatment on antibodies to human alpha6 integrin in OP, seven patients with OP treated with IVIg therapy and a comparable control group of seven patients with OP, treated with conventional therapy, were evaluated at monthly intervals, for a 12 consecutive month treatment period. An effective clinical response was observed in all seven patients treated with IVIg therapy, after a mean treatment period of 4.5 months. IVIg therapy induced a prolonged and sustained clinical remission in all seven patients after a mean treatment period of 26.9 months. A statistically significant difference was observed in the quality of life pre- and post-IVIg therapy (P < 0.001). Both the study and the control groups had a very similar initial serological response to treatment. A statistically significant reduction in the antibody titres was observed after four months of treatment, in both groups (P = 0.015). Thereafter, patients treated with IVIg therapy had a faster rate of decline in the antibody titres, and the difference in the rate of decline between the study and control groups became statistically significant after six months of treatment (P = 0.03). The use of IVIg therapy resulted in reduction of antialpha6 antibody titres and in inducing and maintaining both a sustained, clinical and serological remission.
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Affiliation(s)
- N Sami
- Center for Blistering Diseases, Department of Medicine, New England Baptist Hospital, Boston, MA, USA
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12
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Rout UK, Saed GM, Diamond MP. Transforming growth factor-beta1 modulates expression of adhesion and cytoskeletal proteins in human peritoneal fibroblasts. Fertil Steril 2002; 78:154-61. [PMID: 12095506 DOI: 10.1016/s0015-0282(02)03176-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To determine the effects of TGF-beta1 on the expression of the alpha1, alpha2, alpha5, alpha(v), and alpha6 integrin subunits and on vinculin, and F-actin in human peritoneal fibroblasts. DESIGN Descriptive study using cell culture, reverse transcriptase-polymerase chain reaction (RT-PCR), and immunofluorescent and confocal microscopy. SETTING Academic medical center. PATIENT(S) Gynecological surgery patients. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Effects of TGF-beta1 on the steady state levels of alpha5, alpha(v), and alpha6 integrin transcripts were examined in the normal peritoneal fibroblasts using RT-PCR. Expression levels of the alpha1, alpha2, alpha5, alpha(v), and alpha6 integrin subunits and of F-actin were measured by immunofluorescent microscopy. The distribution pattern of the integrin subunits, vinculin, and F-actin were examined using confocal microscopy. RESULT(S) TGF-beta1 significantly up-regulated the expression levels of the alpha5, alpha(v), and alpha6 integrin subunits and modulated their expression pattern, resulting in relatively higher levels of these subunits in the focal contacts of peritoneal fibroblasts. It allocated vinculin expression primarily to the focal contacts of cells and caused distortion of F-actin structure. The transcript levels of the alpha5, alpha(v), and alpha6 integrin subunits were not altered by TGF-beta1 treatment. CONCLUSION(S) TGF-beta1 may promote postoperative adhesion formation by inducing the migration of peritoneal fibroblasts by altering the expression levels and patterns of specific integrin subunits, vinculin, and F-actin.
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Affiliation(s)
- Ujjwal K Rout
- C. S. Mott Center for Human Growth and Development, Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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13
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Schmelz M, Cress AE, Scott KM, Bürger F, Cui H, Sallam K, McDaniel KM, Dalkin BL, Nagle RB. Different phenotypes in human prostate cancer: alpha6 or alpha3 integrin in cell-extracellular adhesion sites. Neoplasia 2002; 4:243-54. [PMID: 11988844 PMCID: PMC1531698 DOI: 10.1038/sj.neo.7900223] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2001] [Accepted: 08/27/2001] [Indexed: 01/08/2023]
Abstract
The distribution of alpha6/alpha3 integrin in adhesion complexes at the basal membrane in human normal and cancer prostate glands was analyzed in 135 biopsies from 61 patients. The levels of the polarized alpha6/alpha3 integrin expression at the basal membrane of prostate tumor glands were determined by quantitative immunohistochemistry. The alpha6/alpha3 integrin expression was compared with Gleason sum score, pathological stage, and preoperative serum prostate-specific antigen (PSA). The associations were assessed by statistical methods. Eighty percent of the tumors expressed the alpha6 or alpha3 integrin and 20% was integrin-negative. Gleason sum score, but not serum PSA, was associated with the integrin expression. Low Gleason sum score correlated with increased integrin expression, high Gleason sum score with low and negative integrin expression. Three prostate tumor phenotypes were distinguished based on differential integrin expression. Type I coexpressed both alpha6 and alpha3 subunits, type II exclusively expressed alpha6 integrin, and type III expressed alpha3 integrin only. Fifteen cases were further examined for the codistribution of vinculin, paxillin, and CD 151 on frozen serial sections using confocal laser scanning microscopy. The alpha6/alpha3 integrins, CD151, paxillin, and vinculin were present within normal glands. In prostate carcinoma, alpha6 integrin was colocalized with CD 151, but not with vinculin or paxillin. In tumor phenotype I, the alpha6 subunit did not colocalize with the alpha subunit indicating the existence of two different adhesion complexes. Human prostate tumors display on their cell surface the alpha6beta1 and/or alpha3beta1 integrins. Three tumor phenotypes associated with two different adhesion complexes were identified, suggesting a reorganization of cell adhesion structures in prostate cancer.
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Affiliation(s)
- Monika Schmelz
- Department of Pathology, University of Arizona Health Sciences Center, PO Box 24-5043, 1501 North Campbell Avenue, Tucson, AZ 85724-5043, USA.
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14
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Abstract
Hemorrhagic snake venom induces apoptosis in vascular endothelial cells (VEC). In previous reports, we described the purification and cDNA cloning from Crotalus atrox of vascular apoptosis-inducing protein 1 (VAP1) that specifically induces apoptosis in VEC. VAP1 belongs to the metalloprotease/disintegrin family. Yet the mechanism of inducing apoptosis by VAP1 is still not known. Since other various metalloproteases and disintegrins in snake venoms are known to influence extracellular matrix and cell adhesion, we investigated here the involvement of these adhesion molecules in VAP1-induced apoptosis. Consequently, VAP1 induced apoptosis without degrading extracellular matrix or inhibiting adhesion of VEC. However, VAP1-induced apoptosis was inhibited by antibodies for integrin alpha3, alpha6, beta1. Additionally, apoptosis was inhibited by antibody for CD9, an integrin associated protein. These results suggest that integrins are involved in VAP1-induced apoptosis by some specific role rather than that of adhesion to extracellular matrix.
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Affiliation(s)
- Satohiko Araki
- Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, 517-0004, Mie, Japan.
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15
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Xiao W, Wang Y, Liu X, Huang M, Gan T. [Expression of integrin alpha 6 in hepatic sinusoidal capillaration]. Zhonghua Gan Zang Bing Za Zhi 2002; 10:90-2. [PMID: 11983119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To explore the expression of integrin alpha 6 in hepatic sinusoidal capillaration. METHODS The rat hepatic fibrosis model was established by injection of carbon tetrachloride subcutaneously. Then the expression of laminin and integrin alpha 6 subunit was observed by immunohistochemistry and dot immuno-blotting. RESULTS We observed sinusoidal capillaration formed by deposition of laminin along sinusoids in Disse interspace by immunohistochemistry staining. In normal rat the expression of integrin alpha 6 was restricted to portal vascular endothelial cells and bile duct epithelial cell membranes. No expression was observed in sinusoidal endothelial cell membranes. When capillaration integrin alpha 6 was detected in a continuous pattern along the sinusoids, the content of integrin alpha 6 was significantly higher in fibrotic liver tissues than in normal liver tissues as measured by dot immuno-blotting (P<0.05). CONCLUSIONS During fibrogenesis, laminin continuously accumulate in liver tissues and form basement membrane resulting in sinusoidal capillaration, and then induce the expression of integrin alpha 6 on SEC membranes.
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Affiliation(s)
- Wenjun Xiao
- Digestive Medicine Institute of Huaxi Hospital of Sichuan University, Chengdu 610041, China
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16
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Prince JM, Klinowska TCM, Marshman E, Lowe ET, Mayer U, Miner J, Aberdam D, Vestweber D, Gusterson B, Streuli CH. Cell-matrix interactions during development and apoptosis of the mouse mammary gland in vivo. Dev Dyn 2002; 223:497-516. [PMID: 11921338 DOI: 10.1002/dvdy.10070] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Epithelial cell survival is dependent on extracellular signals provided by both soluble factors and by adhesion. In the mammary gland, extensive apoptosis of epithelial cells occurs rapidly when lactation ceases, but the mechanism of apoptosis induction is not known. In tissue culture, mammary epithelial cells require laminin as a survival ligand and specific beta1 integrins are necessary to suppress apoptosis. To explore the possibility that dynamic changes in cell-matrix interactions contribute to the onset of apoptosis during mammary involution in vivo, a detailed immunohistochemical analysis of the expression of integrin subunits and their extracellular matrix ligands during mouse mammary gland development has been performed. The kinetics of apoptosis were determined by using tissue samples obtained from virgin, pregnant, lactating, and involuting gland. The maximal elevation of apoptosis occurred within 24 hr of weaning as determined by histologic analysis and caspase-3 staining. A wide variety of laminin subunits, together with nidogen-1 and -2, and perlecan were identified within the basement membrane region of epithelial ducts, lobules, and alveoli in both human and mouse mammary gland. However, no change in the distribution of any of the basement membrane proteins or their cognate integrin receptors was observed during the transition from lactation to apoptosis. Instead, we discovered that altered ligand-binding conformation of the beta1 integrin to a nonbinding state coincided with the immediate onset of mammary apoptosis. This finding may provide a novel dynamic mechanism for inhibiting the transduction of extracellular matrix survival signals, thereby contributing to the onset of apoptosis in a developmental context in vivo.
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Affiliation(s)
- Janine M Prince
- School of Biological Sciences, University of Manchester, Oxford Road, Manchester, United Kingdom
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17
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Abstract
The development of the mammalian inner ear involves a complex series of cell-cell and cell-extracellular matrix interactions. These interactions are likely to be mediated by families of adhesion molecules, including the integrins. We have studied the expression of three integrin subunits known to be expressed on epithelia in a number of tissues (namely, alpha3, alpha6, and beta4) during the development of the murine inner ear. At E10.5, both alpha3 and alpha6 were expressed in the epithelial layers of the otocyst. The expression of alpha6 was concentrated in an anterioventral region of the epithelium and in a proportion of the cells forming the cochlear-vestibular and facial ganglia. By E12.5, alpha6 showed a more restricted expression, confined mainly to the pro-sensory epithelia and the neural processes from the cochlear-vestibular ganglion. In contrast, alpha3 was expressed in epithelia adjacent to the pro-sensory areas. This reciprocal expression pattern was maintained until birth. Between birth and P6, a switch in expression occurred such that alpha3 was upregulated and alpha6 was downregulated in the sensory epithelia of both the auditory and vestibular systems. At this stage, alpha3 was expressed in all the epithelia lining the scala media, thus defining the endolymph compartment. The expression of beta4 was restricted to epithelial/mesenchymal borders throughout the developmental stages studied, suggesting that alpha6 expression observed within the epithelium and neuronal tissue was alpha6beta1. The early expression and changing pattern of alpha3 and alpha6 integrins during development of the mammalian inner ear suggests that they may be involved in the molecular processes that define epithelial boundaries and guide sensory innervation.
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MESH Headings
- Animals
- Animals, Newborn/embryology
- Animals, Newborn/genetics
- Animals, Newborn/metabolism
- Antigens, CD/biosynthesis
- Antigens, CD/genetics
- Ear, Inner/embryology
- Ear, Inner/growth & development
- Ear, Inner/metabolism
- Embryo, Mammalian/metabolism
- Embryo, Mammalian/physiology
- Female
- Gene Expression Regulation, Developmental/physiology
- Integrin alpha3
- Integrin alpha6
- Integrins/biosynthesis
- Integrins/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Pregnancy
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Affiliation(s)
- Dawn Davies
- Department of Physiology, University of Bristol, School of Medical Sciences, Bristol BS8 1TD, United Kingdom.
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18
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Zhu X, Evans JP. Analysis of the roles of RGD-binding integrins, alpha(4)/alpha(9) integrins, alpha(6) integrins, and CD9 in the interaction of the fertilin beta (ADAM2) disintegrin domain with the mouse egg membrane. Biol Reprod 2002; 66:1193-202. [PMID: 11906941 DOI: 10.1095/biolreprod66.4.1193] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Fertilin beta (also known as ADAM2), a mammalian sperm protein that mediates gamete cell adhesion during fertilization, is a member of the ADAM protein family whose members have disintegrin domains with homology to integrin ligands found in snake venoms. Fertilin beta utilizes an ECD sequence within its disintegrin domain to interact with the egg plasma membrane; the Asp is especially critical. Based on what is known about different integrin subfamilies and their ligands, we sought to characterize fertilin beta binding sites on mouse eggs, focusing on integrin subfamilies that recognize short peptide sequences that include an Asp residue: the alpha(5)/alpha(8)/alpha(v)/alpha(IIb) or RGD-binding subfamily (alpha(5)beta(1), alpha(8)beta(1), alpha(V)beta(1), alpha(V)beta(3), alpha(V)beta(5), alpha(V)beta(6), alpha(V)beta(8), and alpha(IIb)beta(3)) and the alpha(4)/alpha(9) subfamily (alpha(4)beta(1), alpha(9)beta(1), and alpha(4)beta(7)). We tested peptide sequences known to perturb interactions mediated by these integrins in two different assays for fertilin beta binding. Peptides with the sequence MLDG, which perturb alpha(4)/alpha(9) integrin-mediated interactions, significantly inhibit fertilin beta binding to eggs, which suggests a role for a member of this integrin subfamily as a fertilin beta receptor. RGD peptides, which perturb alpha(5)/alpha(8)/alpha(v)/alpha(IIb) integrin-mediated interactions, have partial inhibitory activity. The anti-alpha(6) antibody GoH3 has little or no inhibitory activity. An antibody to the integrin-associated tetraspanin protein CD9 inhibits the binding of a multivalent presentation of fertilin beta (immobilized on beads) but not soluble fertilin beta, which we speculate has implications for the role of CD9 in the strengthening of fertilin beta-mediated cell adhesion but not in initial ligand binding.
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Affiliation(s)
- Xiaoling Zhu
- Department of Biochemistry and Molecular Biology, Division of Reproductive Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, MD 21205, USA
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19
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Walker JL, Zhang L, Zhou J, Woolkalis MJ, Menko AS. Role for alpha 6 integrin during lens development: Evidence for signaling through IGF-1R and ERK. Dev Dyn 2002; 223:273-84. [PMID: 11836791 DOI: 10.1002/dvdy.10050] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We show that alpha 6 integrin function was required for normal lens cell differentiation by using an antisense construct to suppress alpha 6 integrin expression. To elucidate the mechanism by which this integrin functions in the regulation of the lens cell differentiation process, we determined the molecular composition of alpha 6 integrin signaling complexes at distinct stages of differentiation in vivo. Because both alpha 6 integrin and insulin-like growth factor-1 (IGF-1) have been implicated in signaling lens cell differentiation, we examined the possibility that they formed a signaling complex in the embryonic lens. Coprecipitation analysis revealed that alpha 6 integrin/IGF-1 receptor complexes were present and that their association was greatest in the equatorial zone, the region of the embryonic lens in which lens cells proliferate and then initiate their differentiation. These results provide in vivo support for the formation of integrin/growth factor receptor signaling complexes. We also found that extracellular signal-regulated kinase (ERK), a downstream effector of both integrin and growth factor receptor signaling pathways, was associated with the alpha 6 integrin signaling complexes in the embryonic lens. This result was supported by our findings that activated ERK, in addition to its nuclear location, localized to lens cell membranes in specific regions of cell-matrix and cell-cell contact. A connection between integrin ligand engagement and ERK activation was shown in vitro after lens cell attachment to laminin. These results demonstrate that alpha 6 integrin function is required for the early stages of lens cell differentiation most likely through its association with the IGF-1 receptor and the activation of ERK.
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Affiliation(s)
- Janice L Walker
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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20
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Davis TL, Buerger F, Cress AE. Differential regulation of a novel variant of the alpha(6) integrin, alpha(6p). Cell Growth Differ 2002; 13:107-13. [PMID: 11959811 PMCID: PMC2824497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
We have reported previously the existence of an M(r) 70,000 form of the alpha(6) integrin called alpha(6p) in a variety of human epithelial cell lines. Four different experimental conditions were used to examine the regulation of alpha(6) and alpha(6p) integrin. The production of the alpha(6) integrin was decreased by 45% using a protein translation inhibitor (2.25 microM puromycin), whereas production of the alpha(6p) variant was unaffected. The alpha(6p) variant was decreased 60% by actin depolymerization (10 microM cytochalasin D) corresponding to a decrease in its surface expression, whereas alpha(6) integrin production was unaffected. The alpha(6p) variant was resistant to endoglycosidase H treatment, whereas the alpha(6) integrin was both sensitive and resistant to endoglycosidase H treatment, indicating retention in the endoplasmic reticulum and processing through the Golgi apparatus. Additionally, digestion by endoglycosidase F demonstrated both alpha(6p) and alpha(6) integrin contained NH(2)-linked glycosylations and both shifted M(r) approximately 10,000 on enzymatic digestion. Finally, inhibition of serine/threonine phosphatases by either calyculin A (15 nM) or okadaic acid (62 microM) did not affect alpha(6p), whereas the production of alpha(6) integrin was decreased by 50%. These data suggest that the production of the alpha(6p) variant is distinct from alpha(6) integrin and may involve a post-translational processing event at the cell surface.
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Affiliation(s)
- Tracy L. Davis
- Department of Radiation Oncology, Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724-5024
| | - Friederike Buerger
- Department of Radiation Oncology, Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724-5024
| | - Anne E. Cress
- Department of Radiation Oncology, Arizona Cancer Center, University of Arizona, Tucson, Arizona 85724-5024
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85724-5024
- To whom requests for reprints should be addressed, at The Arizona Cancer Center, The University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724-5024. Phone: (520) 626-7553; Fax: (520) 626-4979;
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El Mourabit H, Poinat P, Koster J, Sondermann H, Wixler V, Wegener E, Laplantine E, Geerts D, Georges-Labouesse E, Sonnenberg A, Aumailley M. The PDZ domain of TIP-2/GIPC interacts with the C-terminus of the integrin alpha5 and alpha6 subunits. Matrix Biol 2002; 21:207-14. [PMID: 11852236 DOI: 10.1016/s0945-053x(01)00198-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Different cDNA libraries were screened by the yeast two-hybrid system using as a bait the cytoplasmic sequence of integrin alpha6A or alpha6B subunits. Surprisingly, the same PDZ domain-containing protein, TIP-2/GIPC, was isolated with either of the variants, although their sequences are different. Direct interaction assays with the cytoplasmic domain of the integrin alpha1--7 subunits revealed that in addition to alpha6A and alpha6B, TIP-2/GIPC reacted also with alpha5, but not other alpha integrin subunits. The specificity of the interaction was confirmed by in vitro protein binding assays with purified peptides corresponding to integrin cytoplasmic domains. Further analysis with either truncation fragments of TIP-2/GIPC or mutated integrin cytoplasmic domains indicated that the interaction occurs between the PDZ domain of TIP-2/GIPC and a consensus PDZ domain-binding sequence, SDA, present at the C-terminus of the integrin alpha5 and alpha6A subunits. The integrin alpha6B subunit terminates with a different sequence, SYS, which may represent a new PDZ domain-binding motif.
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Affiliation(s)
- Haquima El Mourabit
- Institute for Biochemistry II, Medical Faculty, University of Cologne, Joseph-Stelzmann-Str. 52, 50931 Cologne, Germany
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22
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Whitacre DC, Chauhan S, Davis T, Gordon D, Cress AE, Miesfeld RL. Androgen induction of in vitro prostate cell differentiation. Cell Growth Differ 2002; 13:1-11. [PMID: 11801526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
To better understand androgen action in normal prostate cells, we characterized the androgen growth response of an immortalized nontumorigenic rat prostate cell line called CA25 that had been stably transfected with androgen receptor (AR) cDNA. Surprisingly, we found that AR(+) CA25 cells grew slower in the presence of dihydrotestosterone (DHT), whereas the growth of AR(-) CA25 cells was not affected by the hormone. DHT-mediated growth inhibition of CA25 cells was not attributable to an increase in apoptosis but rather to a morphological conversion consistent with terminal differentiation. Specifically, we found that DHT treatment of CA25 cells resulted in a striking change in cell architecture, localization of desmoplakin to cell-cell boundaries, and an increase in alpha 6p integrin levels, a newly described marker of cell differentiation. Although no androgen-dependent changes were observed in the transcript levels of the mitochondrial aspartate aminotransferase or c-Myc genes by Northern blot analysis, RNA expression profiling of DHT-treated CA25 cells identified 282 genes of 1,018 that were continually expressed over a 48-h period. It was found that 63 of these genes were up-regulated >5-fold within the first 4 h of treatment and encoded functions involved in transport, signal transduction, and metabolism. These expression profile data are consistent with the striking morphological changes we observed in DHT-treated CA25 cells and provide a starting point for molecular analysis of in vitro prostate cell differentiation.
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Affiliation(s)
- David C Whitacre
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA
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23
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Corley SM, Ladiwala U, Besson A, Yong VW. Astrocytes attenuate oligodendrocyte death in vitro through an alpha(6) integrin-laminin-dependent mechanism. Glia 2001; 36:281-94. [PMID: 11746766 DOI: 10.1002/glia.1116] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Oligodendrocyte (OL) death occurs in many disorders of the CNS, including multiple sclerosis and brain trauma. Factors reported to induce OL death include deprivation of growth factors, elevation of cytokines, oxidative stress, and glutamate excitotoxicity. Because astrocytes produce a large amount of growth factors and antioxidants and are a major source of glutamate uptake, we tested the hypothesis that astrocytes may have a protective role for OL survival. We report that when OLs from the adult mouse brain were initiated into tissue culture, DNA fragmentation and chromatin condensation resulted, indicative of apoptosis. OL death was significantly reduced in coculture with astrocytes, but not with fibroblasts, which provided a similar monolayer of cells as astrocytes. The protection of OL demise by astrocytes was not reproduced by its conditioned medium and was not accounted for by several neurotrophic factors. In contrast, interference with the alpha(6) integrin subunit, but not the alpha(1), alpha(2), alpha(3), alpha(4), alpha(5), or alpha(v) integrin chains, negated astrocyte protection of OLs. Furthermore, a function-blocking antibody to alpha(6)beta(1) integrin reduced the ability of astrocytes to promote OL survival. The extracellular matrix ligand for alpha(6)beta(1) is laminin, which is expressed by astrocytes. Significantly, neutralizing antibodies to laminin-2 and laminin-5 inhibited the astrocyte mediation of OL survival. These results implicate astrocytes in promoting OL survival through a mechanism involving the interaction of alpha(6)beta(1) integrin on OLs with laminin on astrocytes. Enhancing this interaction may provide for OL survival in neurological injury.
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Affiliation(s)
- S M Corley
- Department of Oncology, University of Calgary, Calgary, Alberta, Canada
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24
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Abstract
INTRODUCTION Adhesion of tumor cells to extracellular matrix (ECM) proteins plays an important role in tumor invasion and metastasis. AIMS To investigate the expression of integrins in human pancreatic cancer cell lines and its alteration by interleukin (IL)-1alpha to examine the mechanism of adhesion of metastatic human pancreatic cancer cells to ECM proteins. METHODOLOGY The expression of integrin subunits and their alteration by IL-1alpha were examined by flow-cytometric analysis and cellular enzyme-linked immunosorbent assay in three metastatic human pancreatic cancer cell lines (AsPC-1, BxPC-3, and SW1990) and two nonmetastatic cancer cell lines (PaCa-2 and PANC-1). In addition, assays of cancer cell adhesion to ECM proteins were performed to investigate if increased integrin expression actually affected the adhesive interaction between cancer cells and the putative integrin ECM ligands. RESULTS The alpha(6) subunit expressed in metastatic cancer cells was enhanced by IL-1alpha. Metastatic cancer cells also showed preferential adherence to laminin compared with nonmetastatic cancer cells, and this was enhanced by IL-1alpha. CONCLUSION In pancreatic cancer, the enhancement of alpha(6)beta(1) integrin by IL-1alpha through IL-1 receptor type I, as well as the expression of alpha(6)beta(1) integrin, plays an important role in metastasis formation.
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Affiliation(s)
- H Sawai
- First Department of Surgery, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 4678601, Japan
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25
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Zent R, Bush KT, Pohl ML, Quaranta V, Koshikawa N, Wang Z, Kreidberg JA, Sakurai H, Stuart RO, Nigám SK. Involvement of laminin binding integrins and laminin-5 in branching morphogenesis of the ureteric bud during kidney development. Dev Biol 2001; 238:289-302. [PMID: 11784011 DOI: 10.1006/dbio.2001.0391] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Branching morphogenesis of the ureteric bud (UB) [induced by the metanephric mesenchyme (MM)] is necessary for normal kidney development. The role of integrins in this complex developmental process is not well understood. However, the recent advent of in vitro model systems to study branching of UB cells and isolated UB tissue makes possible a more detailed analysis of the integrins involved. We detected integrin subunits alpha3, alpha6, beta1, and beta4 in both the UB and cells derived from the early UB. Blocking the function of each of these integrin subunits individually markedly inhibited branching morphogenesis in cell culture models. However, inhibiting individual integrin function with blocking antibodies in whole kidney and isolated UB culture only partially inhibited UB branching morphogenesis, suggesting that, in these more complex in vitro systems, multiple integrins are involved in the branching program. In whole organ and isolated bud culture, marked retardation of UB branching was observed only when both alpha3 and alpha6 integrin subunits were inhibited. The alpha6 integrin subunit can be expressed as both alpha6beta1 and alpha6beta4, and both of these beta subunits are important for UB branching morphogenesis in both cell and organ culture. Furthermore, laminin-5, a common ligand for integrins alpha3beta1 and alpha6beta4, was detected in the developing UB and shown to be required for normal UB branching morphogenesis in whole embryonic kidney organ culture as well as isolated UB culture. Together, these data from UB cell culture, organ culture, and isolated UB culture models indicate that both integrin alpha3 and alpha6 subunits play a direct role in UB branching morphogenesis, as opposed to being modulators of the inductive effects of mesenchyme on UB development. Furthermore the data are consistent with a role for laminin-5, acting through its alpha3beta1 and/or alpha6beta4 integrin receptors, in UB branching during nephrogenesis. These data may help to partially explain the renal phenotype seen in integrin alpha3 and alpha3/alpha6 subunit-deficient animals.
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Affiliation(s)
- R Zent
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0693, USA
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Tani TT, Mercurio AM. PDZ interaction sites in integrin alpha subunits. T14853, TIP/GIPC binds to a type I recognition sequence in alpha 6A/alpha 5 and a novel sequence in alpha 6B. J Biol Chem 2001; 276:36535-42. [PMID: 11479315 DOI: 10.1074/jbc.m105785200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We used published peptide library data to identify PDZ recognition sequences in integrin alpha subunit cytoplasmic domains and found that the alpha(6)A and alpha(5) subunits contain a type I PDZ binding site (TSDA*) (asterisk indicates the stop codon). The alpha(6)A cytoplasmic domain was used for screening a two-hybrid library to find interacting proteins. The bulk of the captured cDNAs (60%) coded for TIP-2/GIPC, a cytoplasmic protein with one PDZ domain. The interaction of TIP-2/GIPC with different integrin subunits was tested in two-hybrid and in vitro binding assays. Surprisingly, TIP-2/GIPC bound strongly to the C terminus of both alpha(6)A and alpha(6)B, although the alpha(6)B sequence (ESYS*) is not suggestive of a PDZ binding site because of its polar C-terminal residue. For high affinity interaction with TIP-2/GIPC, at least one of the residues at positions -1 and -3 must be negatively charged. An aliphatic residue at position 0 increases the affinity of but is not required for this interaction. The alpha(5) integrin subunit also bound to TIP-2/GIPC. The alpha(6) integrin and TIP-2/GIPC co-localize in retraction fibers in carcinoma cells plated on laminin, a finding suggesting a functional interaction in vivo. Our results demonstrate that both splice variants of alpha(6) integrin contain a conserved PDZ binding site that enables interaction with TIP-2/GIPC. The binding site in alpha(6)B defines a new subclass of type I PDZ interaction site, characterized by a non-aliphatic residue at position 0.
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Affiliation(s)
- T T Tani
- Division of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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27
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Bergmann-Leitner ES, Bennett TA, Hacker NF, Stromberg K, Stetler-Stevenson WG. Epidermal growth factor receptor signaling and the invasive phenotype of ovarian carcinoma cells. J Natl Cancer Inst 2001; 93:1375-84. [PMID: 11562388 DOI: 10.1093/jnci/93.18.1375] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Most (70%-100%) ovarian carcinomas express high levels of the epidermal growth factor receptor (EGFR). To examine the relationship between EGFR and the invasive phenotype, we assessed integrin expression, adhesion, matrix metalloproteinase (MMP) activity, and migration in ovarian cancer cells in which EGFR expression was modified. METHODS NIH:OVCAR-8 human ovarian carcinoma cells were transfected with an expression vector containing the human EGFR complementary DNA in an antisense orientation (EGFR-antisense cells) or the vector alone (vector control cells). We compared vector control and EGFR-antisense cells for cell morphology and adhesion by light microscopy, expression of alpha(6)- and alpha(3)-integrin subunits by flow cytometry, MMP and tissue inhibitor of MMP (TIMP) activity by zymography, and migration by a wound migration assay. In some experiments, EGFR kinase activity in parental cells was inhibited by treatment with PD153035. All statistical tests were two-sided. RESULTS EGFR-antisense cells were morphologically distinct from vector control cells and had a selective decrease in adhesion to laminin-1 that was not observed with vector control cells (P = .008) or on other extracellular matrix substrates. Compared with vector control cells, cell surface alpha(6)-integrin expression decreased by approximately 80% (difference = 78.7%; 95% confidence interval [CI] = 77.8% to 79.6), MMP-9 activity decreased by approximately 50%, and TIMP activity increased by approximately 50% in EGFR-antisense cells. Vector control cells were highly motile (5.51 arbitrary distance unit; 95% CI = 4.98 to 6.04), whereas the EGFR-antisense cells were not (0.99 arbitrary distance units; 95% CI = 0.38 to 1.60). The morphology and integrin profile of NIH:OVCAR-8 parental cells treated with PD153035 were similar to those of the EGFR-antisense cells. CONCLUSIONS Reduced EGFR expression in ovarian carcinoma cells decreased their adhesion to laminin-1, expression of the alpha(6)-integrin subunit (a well-characterized laminin-1 receptor), and MMP-9 activity. These data support the hypothesis that EGFR overexpression in ovarian cancer cells results in multiple phenotypic changes that enhance the invasive phenotype.
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28
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Geary SM, Cambareri AC, Sincock PM, Fitter S, Ashman LK. Differential tissue expression of epitopes of the tetraspanin CD151 recognised by monoclonal antibodies. Tissue Antigens 2001; 58:141-53. [PMID: 11703821 DOI: 10.1034/j.1399-0039.2001.580301.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
CD151, a member of the tetraspanin family of cell membrane proteins, is widely expressed in epithelial, endothelial and muscle cells as well as platelets and megakaryocytes. Several monoclonal antibodies recognising CD151 in transfected cells and immunoprecipitating typical bands of 28 and 32 kDa from cell lysates have been produced. Surprisingly, these antibodies show different patterns of staining on tissue sections and on haemopoietic cells. Here we show that these differences are at least in part due to masking of certain epitopes in integrin/CD151 complexes. These data have important implications for the use of monoclonal antibodies in studies of the distribution and function of CD151. Of six monoclonal antibodies from four laboratories, 11B1 was found to be the most reliable for detection of CD151 in different cell and tissue contexts.
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Affiliation(s)
- S M Geary
- Division of Haematology, Hanson Centre for Cancer Research, Rundle Mall, Adelaide, SA 5000, Australia
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29
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Kieffer-Combeau S, Meyer JM, Lesot H. Cell-matrix interactions and cell-cell junctions during epithelial histo-morphogenesis in the developing mouse incisor. Int J Dev Biol 2001; 45:733-42. [PMID: 11669375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The continuously growing rodent incisor develops mainly along its antero-posterior axis. The labio-lingual asymmetry which characterizes this tooth is initiated at the cap stage and increases further during the cap to bell transition (ED14 to ED16) when histogenesis of the enamel organ proceeds. Histology, transmission electron microscopy (TEM), and immunostaining were used to document the changes in the basement membrane (BM) as well as the modifications of epithelial cell-matrix and cell-cell interactions during this period. The expression of plakoglobin, desmoglein and E-cadherin at ED14 suggested that the main cell-cell junctional complexes were adherens junctions. The expression of desmoglein and TEM observations suggested a progressive antero-posterior stabilization of the enamel organ by means of desmosomes from ED14 to ED18. alpha6 integrin, BP 230 and laminin gamma2 chain were all expressed in the developing incisor but were not always co-distributed. Immunostaining and TEM suggested that only primitive type II hemidesmosomes were present. At ED14, cells of the enamel knot (EK) did not show any specific expression for antigens involved in cell-cell interaction. However, strong staining for the laminin gamma2 chain characterized the BM in contact with EK cells. The BM in the labial part of the cervical loop demonstrated ultrastructural changes: the presence of loops of the lamina densa in this region preceeded the differential expression of the integrin alpha6 subunit and that of the laminin gamma2 chain in the labial/lingual parts of the cervical loop. Apoptosis was transiently observed in the contiguous mesenchyme. This affected osteoblasts and also nerve cells close to the labial part of the cervical loop.
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Affiliation(s)
- S Kieffer-Combeau
- INSERM U424, Institut de Biologie Médicale, Faculté de Médecine, Strasbourg, France
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Abstract
Cultured prostatic epithelial cells have been extensively studied as a model of prostate biology. What is the lineage relationship of the cultured cells to the epithelial cell types in tissue? How different are cultured cells derived from tumor tissue to those derived from benign tissue? Expression of cluster designation (CD) cell surface molecules has been shown to be useful in characterizing cells according to lineage. A CD profile was therefore generated for cultured human prostatic epithelial cells and compared with those previously established for basal and luminal epithelial cells in the prostate. Presence of CD44, CD49b, CD49f, and CD104 and absence of CD57 suggests that cultured cells were derived from basal cells of prostatic tissues. However, expression of certain CD antigens characteristic of luminal epithelial cells was also observed in subpopulations of cultured cells. The pattern of CD antigens in cultured cells reflects a phenotype similar to that of transit-amplifying cells that have been described in the prostate. Several CD antigens were found expressed by both cultured prostatic epithelial and stromal cells, and are probably associated with cell proliferation. The CD profiles of cultured epithelial cell strains derived from normal compared with malignant tissues were notably similar to each other and to that of the prostate cancer cell line PC-3. We conclude that cells in culture retain expression of certain lineage-characteristic CD antigens. Furthermore, CD antigens can define subpopulations of cells with differential gene expression.
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Affiliation(s)
- A Y Liu
- Department of Urology, University of Washington, Seattle, WA 98195, USA.
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31
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Xiao W, Wang Y, Liu X. [The coordinated expression of laminin and its integrin receptor in hepatic sinusoidal capillarization]. Zhonghua Nei Ke Za Zhi 2001; 40:618-20. [PMID: 11758244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE To explore the expression of laminin and its integrin receptor alpha 6 in sinusoidal capillaration. METHODS The rat hepatic fibrosis model was established by injection carbon tetrachloride subcutaneously. Liver sections were examined by scanning electron microscopy and special staining. Then expressions of laminin and integrin alpha 6 subunit were observed by immunohistochemistry and dot immuno-blotting. RESULTS The pathologic character of hepatic fibrosis-sinusoidal capillaration was observed. Sinusoidal capillaration is characterized by defenestration of sinusoidal endothelial cells (SEC) and basement membrane forming and phenotype transformation. By immunohistochemistry staining. The deposition of laminin surrounding sinusoids according to fibrosis stage was 0, 1.92%, 6.02%, 9.68%, 14.14% respectively, statistically different from each other (P < 0.05). In normal rat no expression of integrin alpha 6 were observed in SEC membranes. When capillaration integrin alpha 6 was detected in a continuous pattern along the sinusoidal in accordance with laminin assembly. The content of integrin alpha 6 in fibrotic liver tissues were significantly higher than in normal liver tissues as measured by dot immuno-blotting (P < 0.05). CONCLUSIONS During fibrogenesis laminin continuously accumulate in liver tissues and form basement membrane resulting in sinusoidal capillaration, meanwhile are company with induced expression of LN-binding-integrin alpha 6 on SEC membranes. These results suggest that coordinated expression of laminin and laminin-binding-integrin might be important in pathogenesis of sinusoidal capillaration and hepatic fibrosis.
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Affiliation(s)
- W Xiao
- Department of Internal Medicine, First Hospital, West China University of Medical Sciences, Chengduo 610041, China
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Kan RK, Pleva CM, Backof DR, Hamilton TA, Petrali JP. Free-floating cryostat sections for immunoelectron microscopy: Bridging the gap from light to electron microscopy. Microsc Res Tech 2001; 54:246-53. [PMID: 11514980 DOI: 10.1002/jemt.1136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Frozen skin sections are routinely used for light microscopic immunohistochemical study of the skin basement membrane zone for two reasons: some skin basement membrane zone proteins are labile to routine chemical fixation, and skin is not amenable to vibratome sectioning. However, inherent limitations of conventional frozen sections, including compromised morphology and a requirement for glass slide-mounting, usually limit immunohistochemical study to the light microscopy level. In the present study, we introduce use of unfixed, free-floating cryostat sections for characterization of immunolocalizations of selected skin basement membrane proteins at both the light and electron microscopy level. The new procedure employs free-floating cryostat sections that can be processed as routine tissue specimens and can be subjected to a variety of special staining procedures including immunohistochemistry. Especially useful is the ease of progressive processing of the same tissue specimen from light microscopy to electron microscopy. In this regard, the method renders itself useful when results of immunolabeling experiments need to be elucidated quickly at histological and ultrastructural levels as required for diagnostic and accelerated investigative strategies.
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Affiliation(s)
- R K Kan
- Comparative Pathology Branch, Comparative Medicine Division, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland 21010, USA.
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Abstract
Mucous membrane pemphigoid or cicatricial pemphigoid is a mucocutaneous blistering disease characterized by autoantibodies to different molecules in the basement membrane zone. Our objectives were to identify the target antigen recognized by sera from 20 untreated patients with pemphigoid disease limited to the oral cavity, and to determine the pathogenicity of autoantibodies in oral pemphigoid, with an organ culture model. We conducted indirect immunofluorescence, immunoblot, and immunoprecipitation assays, with accompanying absorption experiments, using normal human skin, conjunctiva and gingiva, bovine gingiva and a tumor cell line, which were reacted with sera from patients with oral pemphigoid, anti-alpha6 antibody, and control sera. Sera of oral pemphigoid patients selectively and specifically bound to human alpha6 integrin, a 120-kDa protein present in gingiva and the tumor cell line. Oral pemphigoid sera and anti-alpha6 antibody produced separation of epithelium from basement membrane (blister formation) of normal human buccal mucosa, after 48 hours, in organ culture.
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Affiliation(s)
- K C Bhol
- Department of Oral Medicine and Diagnostic Sciences, Harvard School of Dental Medicine, Boston, MA 02115, USA
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Gonzalez RR, Devoto L, Campana A, Bischof P. Effects of leptin, interleukin-1alpha, interleukin-6, and transforming growth factor-beta on markers of trophoblast invasive phenotype: integrins and metalloproteinases. Endocrine 2001; 15:157-64. [PMID: 11720241 DOI: 10.1385/endo:15:2:157] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phenotypic changes of integrin and metalloproteinase secretion of the invasive human cytotrophoblast are regulated by cytokines and growth factors, but how this occurs is not completely understood. We used 24-h cytotrophoblast cultures from first trimester pregnancies to investigate the effects of leptin and cytokines on the expression of the alpha2, alpha5, and alpha6 integrin subunits and on the activity of metalloproteinase-2 (gelatinase A) and metalloproteinase-9 (gelatinase B). The alpha2 subunit was marginally upregulated by leptin and interleukin-1alpha (IL-1alpha). All compounds tested upregulated, in some degree, the alpha5 expression. The a6 integrin subunit was massively upregulated, by leptin, interleukins, and transforming growth factor-beta. None of the factors tested affected metalloproteinase-2 activity, but the activity of metalloproteinase-9 was upregulated by leptin and IL-1alpha. In conclusion, leptin and IL-1alpha actively induce some of the changes that cytotrophoblasts undergo to achieve a more invasive phenotype. A novel role for leptin is proposed during early pregnancy: leptin might be an autocrine/paracrine regulator of cytotrophoblast invasiveness during implantation and placentation.
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Affiliation(s)
- R R Gonzalez
- Boston Biomedical Research Institute, Watertown, MA 02472, USA.
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35
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Lim JM, Kim JA, Lee JH, Joo CK. Downregulated Expression of Integrin α6 by Transforming Growth Factor-β1 on Lens Epithelial Cells in Vitro. Biochem Biophys Res Commun 2001; 284:33-41. [PMID: 11374867 DOI: 10.1006/bbrc.2001.4942] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Integrins represent the main cell surface receptors that mediate cell-matrix and cell-cell interactions. They play critical roles in adhesion, migration, morphogenesis, and the differentiation of several cell types. Previous studies have demonstrated that members of the fibroblast growth factor (FGF)-2, transforming growth factor (TGF)-beta(1), and insulin growth factor (IGF)-1 play important roles in lens biology. In particularly, TGF-beta(1) appears to play a key role in extracellular matrix production, cell proliferation, and cell differentiation of lens epithelial cells. In this study we investigated the effects of FGF-2, TGF-beta(1), and IGF-1 on the modulation of integrin receptors using lens epithelial cell lines (HLE B-3 and alphaTN-4) and lens explants. We found that the expression of integrin alpha6 is downregulated by TGF-beta(1), but is not responsive to FGF-2 or IGF-1. The promoter activity of the integrin alpha6 gene decreased upon TGF-beta(1) treatment in a transient transfection assay, and flow cytometric analysis demonstrated the reduced expression of integrin alpha6 by TGF-beta(1), whereas significant changes were not observed in the level of integrin alpha6 after the addition of FGF-2. These findings suggest that the reduced expression of integrin alpha6 caused by TGF-beta(1) might play a role in the activation of the cell cycle genes required during the fiber differentiation of the lens.
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Affiliation(s)
- J M Lim
- Department of Ophthalmology and Visual Science, College of Medicine, Catholic University of Korea, and Catholic Research Institutes of Medical Sciences, Seoul, Korea
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Fujiwara H, Kikkawa Y, Sanzen N, Sekiguchi K. Purification and characterization of human laminin-8. Laminin-8 stimulates cell adhesion and migration through alpha3beta1 and alpha6beta1 integrins. J Biol Chem 2001; 276:17550-8. [PMID: 11278628 DOI: 10.1074/jbc.m010155200] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recently identified laminin isoforms containing the alpha4 chain have been shown to be expressed in the basement membrane of restricted organs such as heart, skeletal muscle, and blood vessels, especially those in embryos. We screened 38 human cell lines for the expression of the laminin alpha4 chain by reverse transcriptase-polymerase chain reaction and found that T98G glioblastoma cells express only alpha4, but not other alpha chains. Laminin-8, an isoform containing the alpha4 and beta1 chains, was purified from conditioned medium of T98G cells by gel filtration and immunoaffinity chromatography using a monoclonal antibody against laminin beta1 chain. The purified laminin isoform was composed of disulfide-linked 230-, 220-, and 200-kDa subunits, which immunoblot analysis identified as the beta1, gamma1, and alpha4 chains. Purified laminin-8 had cell adhesive activity comparable to laminin-1 but significantly weaker than laminin-5 and laminin-10/11. T98G cells adhering to laminin-8 became more elongated than those adhering to other laminin isoforms and extended multiple pseudopods. Cell adhesion to laminin-8 was abolished by an antibody against the integrin beta1 subunit or a combination of antibodies against the integrin alpha3 and alpha6 subunits, but not by either anti-alpha3 or anti-alpha6 antibody alone, suggesting that both alpha3beta1 and alpha6beta1 integrins serve as adhesion receptors for laminin-8. Consistent with these observations, K562 erythroleukemic cells transfected with either integrin alpha3 or alpha6 cDNA were capable of adhering to laminin-8 when beta1 integrins were stimulated by the beta1-activating antibody 8A2. Despite its moderate cell adhesive activity, laminin-8 was significantly potent in promoting cell migration when compared with other laminin isoforms and fibronectin. Cell migration on laminin-8 was completely inhibited by a combination of antibodies against alpha3 and alpha6 integrins, and substantially inhibited by anti-alpha3 antibody alone, suggesting that laminin-8-mediated cell migration is predominantly mediated by alpha3beta1 integrin. Given its potency to stimulate cell migration and preferential localization to the basement membrane of capillaries and embryonic tissues, laminin-8 may play a role in processes requiring enhanced cell migration during development, wound healing, and angiogenesis.
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Affiliation(s)
- H Fujiwara
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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37
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Klinowska TC, Alexander CM, Georges-Labouesse E, Van der Neut R, Kreidberg JA, Jones CJ, Sonnenberg A, Streuli CH. Epithelial development and differentiation in the mammary gland is not dependent on alpha 3 or alpha 6 integrin subunits. Dev Biol 2001; 233:449-67. [PMID: 11336507 DOI: 10.1006/dbio.2001.0204] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the mammary gland, both laminin and integrins have been shown to be required for normal ductal morphogenesis during development in vivo, and for functional differentiation in culture models. Major integrin receptors for laminins in the mammary gland are alpha 3 beta 1, alpha 6 beta 1, and alpha 6 beta 4. However, the specific subunits that contribute to laminin-mediated mammary cell function and development have not been identified. In this study, we use a genetic approach to test the hypothesis that laminin-binding integrins are required for the function of the mammary gland in vivo. Rudiments of embryonic mammary gland were shown to develop in the absence of these integrin subunits. Postnatal development of the mammary gland was studied in integrin null tissue that had been transplanted into the mammary fat pads of syngeneic hosts. In mammary epithelium lacking alpha 6 integrin, the beta 4 subunit was not apparent and hemidesmosome formation was only rudimentary. However, despite this deficiency, normal ductal morphogenesis and branching of the mammary gland occurred and myoepithelial cells were distributed normally with respect to luminal cells. Mammary alveoli devoid of alpha 3 or alpha 6 integrin formed in pregnancy and were histologically and functionally identical to those in wild-type mammary gland. The tissue underwent full morphological differentiation, and the epithelial cells retained the ability to synthesize beta-casein. This work demonstrates that mammary tissue genetically lacking major laminin-binding integrin receptors is still able to develop and function.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD/physiology
- Basement Membrane/ultrastructure
- Body Patterning/genetics
- Body Patterning/physiology
- Cell Differentiation
- Epithelium/embryology
- Epithelium/growth & development
- Epithelium/metabolism
- Female
- Hemidesmosomes/ultrastructure
- Integrin alpha3
- Integrin alpha6
- Integrin beta4
- Integrins/genetics
- Integrins/physiology
- Laminin/metabolism
- Mammary Glands, Animal/embryology
- Mammary Glands, Animal/growth & development
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/transplantation
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Electron
- Pregnancy
- Transplantation, Isogeneic
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Affiliation(s)
- T C Klinowska
- School of Biological Sciences, University of Manchester, 3.239 Stopford Building, Oxford Road, Manchester, M13 9PT, United Kingdom
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38
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Abstract
The present study was performed to determine the specific receptor of type HPV-16 using recombinant human papillomavirus-like particle (HPV-16 L1-VLP). The expression levels of alpha(6), beta(1), and beta(4) integrins were determined and compared with the amount of HPV-VLP binding in ten cell lines by flow cytometry. Our results show that the amount of VLP binding and the expression level of alpha(6) integrin are correlated, which was confirmed by an inhibition experiment using antibodies and by immunocytochemistry. Both the expression level of alpha(6) integrin and the amount of HPV-VLP binding were high in cervical cancer cell lines, as the type HPV-16 is the main cause of cervical cancer. The degree of binding of HPV-VLP matched the alpha(6) integrin expression level in cell lines but was not correlated with beta(1) and beta(4) levels, which suggests that alpha(6) integrin is the main receptor of HPV type 16.
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Affiliation(s)
- C S Yoon
- Genome Research Center, Korea Research Institute of Bioscience and Biotechnology, Taejeon, 305-600, Korea
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39
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Nishimori H, Yasoshima T, Denno R, Shishido T, Hata F, Honma T, Ura H, Yamaguchi K, Yagihashi A, Tanaka H, Kawaguchi S, Kamiguchi K, Isomura H, Sato N, Hirata K. A new peritoneal dissemination model established from the human pancreatic cancer cell line. Pancreas 2001; 22:348-56. [PMID: 11345134 DOI: 10.1097/00006676-200105000-00003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
We established a new cell line, HPC-3P4a, with high peritoneal disseminated potential in nude mice. HPC-3P4a was derived from a human pancreatic carcinoma cell line (HPC-3) that had low capacity for peritoneal dissemination. HPC-3P4a developed peritoneal dissemination in 10 of 11 (90.9%) cases, whereas parental HPC-3 developed peritoneal dissemination in one of six (16.7%) cases. The metastatic foci in the peritoneum showed essentially the same histologic appearance of parental involvement. The tumorigenicity, motility, and adhesive activity of HPC-3P4a to the extracellular matrix were stronger than were those of the HPC-3. In FACS analysis, HPC-3P4a significantly increased the expression of alpha6 and alpha(v)beta5 integrins, while it decreased alpha2 integrin, hCD44H, and hCD44v 10, as compared with HPC-3. The VEGF production of HPC-3P4a was significantly lower than that of HPC-3. Analysis of gene macroarrays showed a variety of cytokines, interleukin, and other immunomodulatory, and their receptors were up-regulated and down-regulated on an mRNA level in HPC-3P4a cells, compared with HPC-3 cells. Intrasplenic injection of HPC-3P4a produced no liver metastasis. We named our original highly liver metastatic cell line HPC-3H4 (previously reported). This HPC-3H4 cell was established by repeated intrasplenic injection from parental cell HPC-3; thus, it developed high liver metastasis. Moreover, HPC-3H4 developed peritoneal dissemination by intra-abdominal injection. In contrast, HPC-3P4a did not develop liver metastasis by intrasplenic injection. These findings are very interesting and might suggest that the process of hematogenous metastasis differed from that of peritoneal dissemination. Thus, this cell line may be useful for investigating the mechanism of peritoneal dissemination in human pancreatic cancer.
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Affiliation(s)
- H Nishimori
- First Department of Surgery, Sapporo Medical University School of Medicine, Japan
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40
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Cheng EL, Maruyama I, SundarRaj N, Sugar J, Feder RS, Yue BY. Expression of type XII collagen and hemidesmosome-associated proteins in keratoconus corneas. Curr Eye Res 2001; 22:333-40. [PMID: 11600933 DOI: 10.1076/ceyr.22.5.333.5491] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE Keratoconus is a disease characterized by thinning of the central and paracentral cornea and scarring in advanced cases. This study was performed to examine the expression of type XII collagen, proteins associated with hemidesmosomes, and beta1 integrin in keratoconus corneas. METHODS Corneal buttons were collected from normal subjects and patients with keratoconus and other corneal diseases. Immunofluorescence staining was performed on frozen sections for type XII collagen, bullous pemphigoid antigen (BP180), and integrin subunits alpha6, beta4, and beta1. RESULTS To varying degrees, all proteins examined were expressed in normal human corneas. The staining intensity of type XII collagen was diminished in keratoconus corneas in the epithelial basement membrane zone and the stromal matrix. No significant variation was found in either the staining patterns or intensities for BP180, or integrins alpha6, beta4, and beta1. CONCLUSIONS The level of type XII collagen was reduced in the epithelial basement membrane zone and stromal matrices in keratoconus corneas. These alterations may affect critical interactions of the corneal epithelium with the under-lying basement membrane, and cell-matrix interactions and matrix organization in the stroma.
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Affiliation(s)
- E L Cheng
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
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41
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Pons S, Trejo JL, Martínez-Morales JR, Martí E. Vitronectin regulates Sonic hedgehog activity during cerebellum development through CREB phosphorylation. Development 2001; 128:1481-92. [PMID: 11290288 DOI: 10.1242/dev.128.9.1481] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During development of the cerebellum, Sonic hedgehog (SHH) is expressed in migrating and settled Purkinje neurons and is directly responsible for proliferation of granule cell precursors in the external germinal layer. We have previously demonstrated that SHH interacts with vitronectin in the differentiation of spinal motor neurons. Here, we analysed whether similar interactions between SHH and extracellular matrix glycoproteins regulate subsequent steps of granule cell development. Laminins and their integrin receptor subunit alpha6 accumulate in the outer most external germinal layer where proliferation of granule cell precursors is maximal. Consistent with this expression pattern, laminin significantly increases SHH-induced proliferation in primary cultures of cerebellar granule cells. Vitronectin and its integrin receptor subunits alpha(v) are expressed in the inner part of the external germinal layer where granule cell precursors exit the cell cycle and commence differentiation. In cultures, vitronectin is able to overcome SHH-induced proliferation, thus allowing granule cell differentiation. Our studies indicate that the pathway in granule cell precursors responsible for the conversion of a proliferative SHH-mediated response to a differentiation signal depends on CREB. Vitronectin stimulates phosphorylation of cyclic-AMP responsive element-binding protein (CREB), and over-expression of CREB is sufficient to induce granule cell differentiation in the presence of SHH. Taken together, these data suggest that granule neuron differentiation is regulated by the vitronectin-induced phosphorylation of CREB, a critical event that terminates SHH-mediated proliferation and permits the differentiation program to proceed in these cells.
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Affiliation(s)
- S Pons
- Instituto Cajal de Neurobiología, CSIC, Av. Doctor Arce 37, Madrid E28002, Spain
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42
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Takahashi Y, Bigler D, Ito Y, White JM. Sequence-specific interaction between the disintegrin domain of mouse ADAM 3 and murine eggs: role of beta1 integrin-associated proteins CD9, CD81, and CD98. Mol Biol Cell 2001; 12:809-20. [PMID: 11294888 PMCID: PMC32268 DOI: 10.1091/mbc.12.4.809] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
ADAM 3 is a sperm surface glycoprotein that has been implicated in sperm-egg adhesion. Because little is known about the adhesive activity of ADAMs, we investigated the interaction of ADAM 3 disintegrin domains, made in bacteria and in insect cells, with murine eggs. Both recombinant proteins inhibited sperm-egg binding and fusion with potencies similar to that which we recently reported for the ADAM 2 disintegrin domain. Alanine scanning mutagenesis revealed a critical importance for the glutamine at position 7 of the disintegrin loop. Fluorescent beads coated with the ADAM 3 disintegrin domain bound to the egg surface. Bead binding was inhibited by an authentic, but not by a scrambled, peptide analog of the disintegrin loop. Bead binding was also inhibited by the function-blocking anti-alpha6 monoclonal antibody (mAb) GoH3, but not by a nonfunction blocking anti-alpha6 mAb, or by mAbs against either the alphav or beta3 integrin subunits. We also present evidence that in addition to the tetraspanin CD9, two other beta1-integrin-associated proteins, the tetraspanin CD81 as well as the single pass transmembrane protein CD98 are expressed on murine eggs. Antibodies to CD9 and CD98 inhibited in vitro fertilization and binding of the ADAM 3 disintegrin domain. Our findings are discussed in terms of the involvement of multiple sperm ADAMs and multiple egg beta1 integrin-associated proteins in sperm-egg binding and fusion. We propose that an egg surface "tetraspan web" facilitates fertilization and that it may do so by fostering ADAM-integrin interactions.
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Affiliation(s)
- Y Takahashi
- Department of Cell Biology, University of Virginia Health System, School of Medicine, Charlottesville, Virginia 22908, USA
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43
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Stucki A, Rivier AS, Gikic M, Monai N, Schapira M, Spertini O. Endothelial cell activation by myeloblasts: molecular mechanisms of leukostasis and leukemic cell dissemination. Blood 2001; 97:2121-9. [PMID: 11264180 DOI: 10.1182/blood.v97.7.2121] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leukostasis and tissue infiltration by leukemic cells are poorly understood life-threatening complications of acute leukemia. This study has tested the hypothesis that adhesion receptors and cytokines secreted by blast cells play central roles in these reactions. Immunophenotypic studies showed that acute myeloid leukemia (AML) cells (n = 78) of the M0 to M5 subtypes of the French-American-British Cooperative Group expressed various amounts of adhesion receptors, including CD11a, b, c/CD18, CD49d, e, f/CD29, CD54, sCD15, and L-selectin. The presence of functional adhesion receptors was evaluated using a nonstatic adhesion assay. The number of blast cells attached to unactivated endothelium increased by 7 to 31 times after a 6-hour exposure of endothelium to tumor necrosis factor (TNF)-alpha. Inhibition studies showed that multiple adhesion receptors--including L-selectin, E-selectin, VCAM-1, and CD11/CD18--were involved in blast cell adhesion to TNF-alpha-activated endothelium. Leukemic cells were then cocultured at 37 degrees C on unactivated endothelial cell monolayers for time periods up to 24 hours. A time-dependent increase in the number of blasts attached to the endothelium and a concomitant induction of ICAM-1, VCAM-1, and E-selectin were observed. Additional experiments revealed that endothelial cell activation by leukemic myeloblasts was caused by cytokine secretion by blast cells, in particular TNF-alpha and IL-1 beta, and direct contacts between adhesion receptors expressed by blast cells and endothelial cells. Thus, leukemic cells have the ability to generate conditions that promote their own adhesion to vascular endothelium, a property that may have important implications for the pathophysiology of leukostasis and tissue infiltration by leukemic blast cells. (Blood. 2001;97:2121-2129)
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MESH Headings
- Antigens, CD/biosynthesis
- Antigens, CD/genetics
- CD18 Antigens/biosynthesis
- CD18 Antigens/genetics
- Cell Adhesion
- Cell Adhesion Molecules/biosynthesis
- Cell Adhesion Molecules/genetics
- Cells, Cultured
- Coculture Techniques
- E-Selectin/biosynthesis
- E-Selectin/genetics
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Gene Expression Regulation, Leukemic
- Humans
- Integrin alpha4
- Integrin alpha5
- Integrin alpha6
- Integrin alphaXbeta2/biosynthesis
- Integrin alphaXbeta2/genetics
- Integrin beta1/biosynthesis
- Integrin beta1/genetics
- Intercellular Adhesion Molecule-1/biosynthesis
- Intercellular Adhesion Molecule-1/genetics
- Interleukin-1/metabolism
- L-Selectin/biosynthesis
- L-Selectin/genetics
- Leukemia, Myeloid/genetics
- Leukemia, Myeloid/metabolism
- Leukemia, Myeloid/pathology
- Leukemic Infiltration/genetics
- Leukemic Infiltration/metabolism
- Leukostasis/genetics
- Leukostasis/metabolism
- Lewis X Antigen/biosynthesis
- Lewis X Antigen/genetics
- Lymphocyte Function-Associated Antigen-1/biosynthesis
- Lymphocyte Function-Associated Antigen-1/genetics
- Macrophage-1 Antigen/biosynthesis
- Macrophage-1 Antigen/genetics
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Neoplastic Stem Cells/cytology
- Neoplastic Stem Cells/metabolism
- Receptors, Lymphocyte Homing/biosynthesis
- Receptors, Lymphocyte Homing/genetics
- Tumor Cells, Cultured
- Tumor Necrosis Factor-alpha/metabolism
- Vascular Cell Adhesion Molecule-1/biosynthesis
- Vascular Cell Adhesion Molecule-1/genetics
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Affiliation(s)
- A Stucki
- Division and Central Laboratory of Hematology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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Abstract
BACKGROUND Integrin receptors mediate cell-extracellular matrix interactions and regulate many events, including cell growth, proliferation, and differentiation. Retinal integrins are incompletely understood, although these receptors are potentially important factors in normal retinal function and pathology. METHODS Immunocytochemistry was used to localize alpha integrin subunits 1-6 in the neural retina. RESULTS Each alpha integrin subunit had a unique distribution in the retina, although there was considerable overlap among subunits. The alpha 1 subunit was broadly distributed throughout the retina, with some presumptive ganglion cells showing enriched labeling. The alpha 2 subunit was present on all retinal cell bodies, but was reduced in synaptic layers. The alpha 3 subunit was present in synaptic layers, Müller cells, and some cone and amacrine cells. The alpha 4 subunit was broadly distributed in the nuclear layers but was reduced in synaptic layers. The alpha 5 subunit was broadly expressed in the nuclear and synaptic layers with enriched labeling in the outer plexiform layer. Labeling for the alpha 6 subunit was restricted to the outer limiting membrane and some cone outer segments. Double-labeling studies indicated that photoreceptor terminals may exhibit alpha 1 and alpha 5 subunits, while processes from second-order neurons may exhibit alpha 1, alpha 3, and alpha 5 subunits. CONCLUSION Integrin receptors containing the alpha 1, alpha 3, and alpha 5 subunits may have important functions at retinal synapses, in addition to roles in the nuclear layers. Integrin receptors containing alpha 2, alpha 4, and alpha 6 subunits probably serve non-synaptic functions.
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Affiliation(s)
- D M Sherry
- University of Houston, College of Optometry, 505 J Davis Armistead Bldg, Houston, TX 77204-2020, USA.
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45
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Kedzia W, Schmidt M, Jasiński P, Spaczyński M. [Integrin alpha-6 in cervix neck squamous cell carcinoma HPV 16/18 positive and negative]. Ginekol Pol 2001; 72:207-11. [PMID: 11444176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
In the present paper we study expression of alpha-6 integrin in normal paraepidermal epithelium, in CIN and in cervical invasive carcinoma HPV 16/18 positive and negative. The results suggest that alpha-6 integrin might be a marker for the evaluation of malignancy of squamous cell carcinoma. There is no correlation between the expression of alpha-6 integrin and the presence of HPV.
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Affiliation(s)
- W Kedzia
- Katedry Ginekologii i Połoznictwa AM w Poznaniu
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46
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Abstract
Segmenting individual cell nuclei from microscope images normally involves volume labelling of the nuclei with a DNA stain. However, this method often fails when the nuclei are tightly clustered in the tissue, because there is little evidence from the images on where the borders of the nuclei are. In this paper we present a method which solves this limitation and furthermore enables segmentation of whole cells. Instead of using volume stains, we used stains that specifically label the surface of nuclei or cells: lamins for the nuclear envelope and alpha-6 or beta-1 integrins for the cellular surface. The segmentation is performed by identifying unique seeds for each nucleus/cell and expanding the boundaries of the seeds until they reach the limits of the nucleus/cell, as delimited by the lamin or integrin staining, using gradient-curvature flow techniques. We tested the algorithm using computer-generated objects to evaluate its robustness against noise and applied it to cells in culture and to tissue specimens. In all the cases that we present the algorithm gave accurate results.
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Affiliation(s)
- C O De Solorzano
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, U.S.A
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47
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Abstract
Hemidesmosome (HD) is a transmembrane complex that mediates attachment of epithelial cells to the basement membrane. Abnormal expression of HD components has been reported in several types of human cancers and is believed to play a role in tumor invasion and metastasis. Using differential gene display, we have identified downregulation of BPAG1 expression in nasopharyngeal carcinoma cells. BPAG1 is a major component of hemidesmosome. In the present study, we have extended our work to investigate the expression pattern of other components in the HD complex, namely, BPAG2, ITGalpha6 and ITGbeta4 in three distinct biological groups of nasopharyngeal epithelial cells: (a) non-malignant nasopharyngeal epithelial cells established from primary culture of nasopharyngeal explants, (b) non-malignant nasopharyngeal epithelial cells immortalized by viral oncogenes, SV40 or HPV16E6E7, and (c) nasopharyngeal carcinoma (NPC) cells. Both non-malignant primary cultured nasopharyngeal epithelial cells and immortalized nasopharyngeal epithelial cell lines expressed all the HD components examined, although the immortalized cells expressed a lower level of HD components compared with the non-malignant nasopharyngeal cells established from primary culture. In contrast, downregulation of HD components is commonly observed in nasopharyngeal carcinoma cells. Loss of HD expression in NPC may be associated with the undifferentiated properties of NPC cells and may have prognostic significance.
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Affiliation(s)
- A K Lo
- Department of Anatomy, Faculty of Medicine, The University of Hong Kong, 5 Sassoon Road, Pokfulam, Hong Kong, China
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48
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Jiang FX, Georges-Labouesse E, Harrison LC. Regulation of laminin 1-induced pancreatic beta-cell differentiation by alpha6 integrin and alpha-dystroglycan. Mol Med 2001; 7:107-14. [PMID: 11471545 PMCID: PMC1950020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
BACKGROUND The ability to manipulate the development of pancreatic insulin-producing beta cells has implications for the treatment of type 1 diabetes. Previously, we found that laminin-1, a basement membrane trimeric glycoprotein, promotes beta-cell differentiation. We have investigated the mechanism of this effect, using agents that block the receptors for laminin-1, alpha6 integrin, and alpha-dystroglycan (alpha-DG). MATERIALS AND METHODS Dissociated cells from 13.5-day postcoitum (dpc) fetal mouse pancreas were cultured for 4 days with laminin-1, with and without monoclonal antibodies and other agents known to block integrins or alpha-DG. Fetuses fixed in Bouin's solution or fetal pancreas cells fixed in 4% paraformaldehyde were processed for routine histology and for immunohistology to detect hormone expression and bromodeoxyuridine (BrdU) uptake. RESULTS Blocking the binding of laminin-1 to alpha6 integrin with a monoclonal antibody, GoH3, abolished cell proliferation (BrdU uptake) and doubled the number of beta cells. Inhibition of molecules involved in alpha6 integrin signaling (phosphotidylinositol 3-kinase, F-actin, or mitogen-activated protein kinase) had a similar effect. Nevertheless, beta cells appeared to develop normally in alpha6 integrin-deficient fetuses. Blocking the binding of laminin-1 to alpha-DG with a monoclonal antibody, IIH6, dramatically decreased the number of beta cells. Heparin, also known to inhibit laminin-1 binding to alpha-DG, had a similar effect. In the presence of heparin, the increase in beta cells in response to blocking alpha integrin with GoH3 was abolished. CONCLUSIONS These findings reveal an interplay between alpha6 integrin and alpha-DG to regulate laminin-1-induced beta-cell development. Laminin-I had a dominant effect via alpha-DG to promote cell survival and beta-cell differentiation, which was modestly inhibited by alpha6 signaling.
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Affiliation(s)
- F X Jiang
- Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, Australia
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49
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Abstract
Using pseudoinfection of cell lines, we demonstrate that cell surface heparan sulfate is required for infection by human papillomavirus type 16 (HPV-16) and HPV-33 pseudovirions. Pseudoinfection was inhibited by heparin but not dermatan or chondroitin sulfate, reduced by reducing the level of surface sulfation, and abolished by heparinase treatment. Carboxy-terminally deleted HPV-33 virus-like particles still bound efficiently to heparin. The kinetics of postattachment neutralization by antiserum or heparin indicated that pseudovirions were shifted on the cell surface from a heparin-sensitive into a heparin-resistant mode of binding, possibly involving a secondary receptor. Alpha-6 integrin is not a receptor for HPV-33 pseudoinfection.
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Affiliation(s)
- T Giroglou
- Institute for Medical Microbiology and Hygiene, University of Mainz, 55101 Mainz, Germany
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50
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Dans M, Gagnoux-Palacios L, Blaikie P, Klein S, Mariotti A, Giancotti FG. Tyrosine phosphorylation of the beta 4 integrin cytoplasmic domain mediates Shc signaling to extracellular signal-regulated kinase and antagonizes formation of hemidesmosomes. J Biol Chem 2001; 276:1494-502. [PMID: 11044453 DOI: 10.1074/jbc.m008663200] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ligation of the alpha(6)beta(4) integrin induces tyrosine phosphorylation of the beta(4) cytoplasmic domain, followed by recruitment of the adaptor protein Shc and activation of mitogen-activated protein kinase cascades. We have used Far Western analysis and phosphopeptide competition assays to map the sites in the cytoplasmic domain of beta(4) that are required for interaction with Shc. Our results indicate that, upon phosphorylation, Tyr(1440), or secondarily Tyr(1422), interacts with the SH2 domain of Shc, whereas Tyr(1526), or secondarily Tyr(1642), interacts with its phosphotyrosine binding (PTB) domain. An inactivating mutation in the PTB domain of Shc, but not one in its SH2 domain, suppresses the activation of Shc by alpha(6)beta(4). In addition, mutation of beta(4) Tyr(1526), which binds to the PTB domain of Shc, but not of Tyr(1422) and Tyr(1440), which interact with its SH2 domain, abolishes the activation of ERK by alpha(6)beta(4). Phenylalanine substitution of the beta(4) tyrosines able to interact with the SH2 or PTB domain of Shc does not affect incorporation of alpha(6)beta(4) in the hemidesmosomes of 804G cells. Exposure to the tyrosine phosphatase inhibitor orthovanadate increases tyrosine phosphorylation of beta4 and disrupts the hemidesmosomes of 804G cells expressing recombinant wild type beta(4). This treatment, however, exerts a decreasing degree of inhibition on the hemidesmosomes of cells expressing versions of beta(4) containing phenylalanine substitutions at Tyr(1422) and Tyr(1440), at Tyr(1526) and Tyr(1642), or at all four tyrosine phosphorylation sites. These results suggest that beta(4) Tyr(1526) interacts in a phosphorylation-dependent manner with the PTB domain of Shc. This event is required for subsequent tyrosine phosphorylation of Shc and signaling to ERK but not formation of hemidesmosomes.
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Affiliation(s)
- M Dans
- Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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