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Harada-Kagitani S, Kouchi Y, Shinomiya Y, Kodama M, Ohira G, Matsubara H, Ikeda JI, Kishimoto T. Keratin 6A Is Expressed at the Invasive Front and Enhances the Progression of Colorectal Cancer. J Transl Med 2024; 104:102075. [PMID: 38729352 DOI: 10.1016/j.labinv.2024.102075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/25/2024] [Accepted: 05/01/2024] [Indexed: 05/12/2024] Open
Abstract
Keratins (KRTs) are intermediate filament proteins in epithelial cells, and they are important for cytoskeletal organization. KRT6A, classified as a type II KRT, is normally expressed in stratified squamous epithelium and squamous cell carcinomas. Little is known about the expression and role of KRT6A in adenocarcinomas. We investigated the clinicopathologic and molecular biological significance of KRT6A in colorectal adenocarcinoma. Immunostaining of colorectal adenocarcinoma cases treated at our institution demonstrated that KRT6A showed significantly stronger expression at the invasive front than that at the tumor center (P < .0001). The high KRT6A-expression cases (n = 47) tended to have a high budding grade associated with significantly worse prognoses. A multivariate analysis revealed that the KRT6A expression status was an independent prognostic factor for overall survival (P = .0004), disease-specific survival (P = .0097), and progression-free survival (P = .0033). The correlation between KRT6A and patient prognoses was also validated in an external cohort from a published data set. To determine the function of KRT6A in vitro, KRT6A was overexpressed in 3 colon cancer cell lines: DLD-1, SW620, and HCT 116. KRT6A overexpression increased migration and invasion in DLD-1 but did not in SW620 and HCT116. In 3-dimensional sphere-forming culture, KRT6A expression enhanced the irregular protrusion around the spheroid in DLD-1. Our findings in this study indicated that KRT6A expression is a valuable prognostic marker of colorectal cancer and KRT6A may be involved the molecular mechanism in the progression of invasive areas of colorectal cancer.
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Affiliation(s)
- Sakurako Harada-Kagitani
- Department of Molecular Pathology, Chiba University Graduate School of Medicine, Chiba, Japan; Department of Pathology, Chiba University Hospital, Chiba, Japan
| | - Yusuke Kouchi
- Department of Molecular Pathology, Chiba University Graduate School of Medicine, Chiba, Japan; Department of Pathology, Chiba University Hospital, Chiba, Japan
| | - Yoshiki Shinomiya
- Department of Molecular Pathology, Chiba University Graduate School of Medicine, Chiba, Japan; Department of Pathology, Chiba University Hospital, Chiba, Japan
| | - Makoto Kodama
- Department of Pathology, Tokyo Yamate Medical Center, Tokyo, Japan
| | - Gaku Ohira
- Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Hisahiro Matsubara
- Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Jun-Ichiro Ikeda
- Department of Pathology, Chiba University Hospital, Chiba, Japan; Department of Diagnostic Pathology, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Takashi Kishimoto
- Department of Molecular Pathology, Chiba University Graduate School of Medicine, Chiba, Japan.
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2
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Zuccolini P, Gavazzo P, Pusch M. BK Channel in the Physiology and in the Cancer of Pancreatic Duct: Impact and Reliability of BK Openers. Front Pharmacol 2022; 13:906608. [PMID: 35685628 PMCID: PMC9171006 DOI: 10.3389/fphar.2022.906608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
BK (KCa 1.1, Slo-1) is a K+ channel characterized by an allosteric regulation of the gating mechanism by Ca2+ binding and voltage, and a high unitary conductance. The channel is expressed in many different tissues, where it is involved in the regulation or the fine-tuning of many physiological processes. Among other organs, BK is expressed in the pancreatic duct, a part of the gland important for the correct ionic composition of the pancreatic juice. Unfortunately, the pancreatic duct is also the site where one of the deadliest cancer types, the pancreatic duct adenocarcinoma (PDAC), develops. In the past years, it has been reported that continuous exposure of cancer cells to BK openers can have a significant impact on cell viability as well as on the ability to proliferate and migrate. Here, we first summarize the main BK channel properties and its roles in pancreatic duct physiology. Then we focus on the potential role of BK as a pharmacological target in PDAC. Moreover, we discuss how results obtained when employing BK activators on cancer cells can, in some cases, be misleading.
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Gonzalez-Perez V, Zhou Y, Ciorba MA, Lingle CJ. The LRRC family of BK channel regulatory subunits: potential roles in health and disease. J Physiol 2022; 600:1357-1371. [PMID: 35014034 PMCID: PMC8930516 DOI: 10.1113/jp281952] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/04/2022] [Indexed: 11/08/2022] Open
Abstract
Large conductance K+ channels, termed BK channels, regulate a variety of cellular and physiological functions. Although universally activated by changes in voltage or [Ca2+ ]i , the threshold for BK channel activation varies among loci of expression, often arising from cell-specific regulatory subunits including a family of leucine rich repeat-containing (LRRC) γ subunits (LRRC26, LRRC52, LRRC55 and LRRC38). The 'founding' member of this family, LRRC26, was originally identified as a tumour suppressor in various cancers. An LRRC26 knockout (KO) mouse model recently revealed that LRRC26 is also highly expressed in secretory epithelial cells and partners with BK channels in the salivary gland and colonic goblet cells to promote sustained K+ fluxes likely essential for normal secretory function. To accomplish this, LRRC26 negatively shifts the range of BK channel activation such that channels contribute to K+ flux near typical epithelial cell resting conditions. In colon, the absence of LRRC26 increases vulnerability to colitis. LRRC26-containing BK channels are also likely important regulators of epithelial function in other loci, including airways, female reproductive tract and mammary gland. Based on an LRRC52 KO mouse model, LRRC52 regulation of large conductance K+ channels plays a role both in sperm function and in cochlear inner hair cells. Although our understanding of LRRC-containing BK channels remains rudimentary, KO mouse models may help define other organs in which LRRC-containing channels support normal function. A key topic for future work concerns identification of endogenous mechanisms, whether post-translational or via gene regulation, that may impact LRRC-dependent pathologies.
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Affiliation(s)
- Vivian Gonzalez-Perez
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., Saint Louis, MO 63110 USA
| | - Yu Zhou
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., Saint Louis, MO 63110 USA
| | - Matthew A. Ciorba
- Department of Internal Medicine, Division of Gastroenterology, Washington University School of Medicine, St. Louis MO 63110 USA
| | - Christopher J. Lingle
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Ave., Saint Louis, MO 63110 USA
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Xu X, Gong C, Wang Y, Hu Y, Liu H, Fang Z. Multi-omics analysis to identify driving factors in colorectal cancer. Epigenomics 2020; 12:1633-1650. [PMID: 32573269 DOI: 10.2217/epi-2020-0073] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aim: We aim to identify driving genes of colorectal cancer (CRC) through multi-omics analysis. Materials & methods: We downloaded multi-omics data of CRC from The Cancer Genome Atlas dataset. Integrative analysis of single-nucleotide variants, copy number variations, DNA methylation and differentially expressed genes identified candidate genes that carry CRC risk. Kernal genes were extracted from the weighted gene co-expression network analysis. A competing endogenous RNA network composed of CRC-related genes was constructed. Biological roles of genes were further investigated in vitro. Results: We identified LRRC26 and REP15 as novel prognosis-related driving genes for CRC. LRRC26 hindered tumorigenesis of CRC in vitro. Conclusion: Our study identified novel driving genes and may provide new insights into the molecular mechanisms of CRC.
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Affiliation(s)
- Xi Xu
- Department of Pathology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009, China
| | - Chaoju Gong
- Central Laboratory, The Municipal Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221106, PR China
| | - Yunfeng Wang
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS, Commissariat à l'Energie Atomique et aux Énergies Alternatives (CEA), Université Paris-Sud, 91198 Gif-sur-Yvette, Palaiseau, 91120, France
| | - Yanyan Hu
- Central Laboratory, Sanmen People's Hospital of Zhejiang Province, Sanmen, 317100, PR China
| | - Hong Liu
- Zhejiang Normal University - Jinhua People's Hospital Joint Center for Biomedical Research, Jinhua, 321004, PR China.,The Affiliated Hospital of Jinhua Polytechnic College, Jinhua, 321000, PR China
| | - Zejun Fang
- Central Laboratory, Sanmen People's Hospital of Zhejiang Province, Sanmen, 317100, PR China.,Central Laboratory, Sanmenwan Branch, The First Affiliated Hospital, College of Medicine, Zhejiang University, Sanmen, 317100, PR China
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Noda S, Chikazawa K, Suzuki Y, Imaizumi Y, Yamamura H. Involvement of the γ1 subunit of the large-conductance Ca 2+-activated K + channel in the proliferation of human somatostatinoma cells. Biochem Biophys Res Commun 2020; 525:1032-1037. [PMID: 32178873 DOI: 10.1016/j.bbrc.2020.02.176] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 02/28/2020] [Indexed: 10/24/2022]
Abstract
Pancreatic neuroendocrine tumors (pNETs) occur due to the abnormal growth of pancreatic islet cells and predominantly develop in the duodenal-pancreatic region. Somatostatinoma is one of the pNETs associated with tumors of pancreatic δ cells, which produce and secrete somatostatin. Limited information is currently available on the pathogenic mechanisms of somatostatinoma. The large-conductance Ca2+-activated K+ (BKCa) channel is expressed in several types of cancer cells and regulates cell proliferation, migration, invasion, and metastasis. In the present study, the functional expression of the BKCa channel was examined in a human somatostatinoma QGP-1 cell line. In QGP-1 cells, outward currents were elicited by membrane depolarization at pCa 6.5 (300 nM) in the pipette solution and inhibited by the specific BKCa channel blocker, paxilline. Paxilline-sensitive currents were detected, even at pCa 8.0 (10 nM) in the pipette solution, in QGP-1 cells. In addition to the α and β2-4 subunits of the BKCa channel, the novel regulatory γ1 subunit (BKCaγ1) was co-localized with the α subunit in QGP-1 cells. Paxilline-sensitive currents at pCa 8.0 in the pipette solution were reduced by the siRNA knockdown of BKCaγ1. Store-operated Ca2+ entry was smaller in BKCaγ1 siRNA-treated QGP-1 cells. The proliferation of QGP-1 cells was attenuated by paxilline or the siRNA knockdown of BKCaγ1. These results strongly suggest that BKCaγ1 facilitates the proliferation of human somatostatinoma cells. Therefore, BKCaγ1 may be a novel therapeutic target for somatostatinoma.
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Affiliation(s)
- Sayuri Noda
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori Mizuhoku, Nagoya, 467-8603, Japan
| | - Kana Chikazawa
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori Mizuhoku, Nagoya, 467-8603, Japan
| | - Yoshiaki Suzuki
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori Mizuhoku, Nagoya, 467-8603, Japan
| | - Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori Mizuhoku, Nagoya, 467-8603, Japan
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabedori Mizuhoku, Nagoya, 467-8603, Japan.
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6
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Noda S, Suzuki Y, Yamamura H, Giles WR, Imaizumi Y. Roles of LRRC26 as an auxiliary γ1-subunit of large-conductance Ca 2+-activated K + channels in bronchial smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2020; 318:L366-L375. [PMID: 31800260 DOI: 10.1152/ajplung.00331.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In visceral smooth muscle cells (SMCs), the large-conductance Ca2+-activated K+ (BK) channel is one of the key elements underlying a negative feedback mechanism that is essential for the regulation of intracellular Ca2+ concentration. Although leucine-rich repeat-containing (LRRC) proteins have been identified as novel auxiliary γ-subunits of the BK channel (BKγ) in several cell types, its physiological roles in SMCs are unclear. The BKγ expression patterns in selected SM tissues were examined using real-time PCR analyses and Western blotting. The functional contribution of BKγ1 to BK channel activity was examined by whole cell patch-clamp in SMCs and heterologous expression systems. BKγ1 expression in mouse bronchial SMCs (mBSMCs) was higher than in other several SMC types. Coimmunoprecipitation and total internal reflection fluorescence imaging analyses revealed molecular interaction between BKα and BKγ1 in mBSMCs. Under voltage-clamp, steady-state activation of BK channel currents at pCa 8.0 in mBSMCs occurred in a voltage range comparable to that of reconstituted BKα/BKγ1 complex. However, this range was much more negative than in mouse aortic SMCs (mASMCs) or in HEK293 cells expressing BKα alone and β-subunit (BKβ1). Mallotoxin, a selective activator of BK channel that lacks BKγ1, dose-dependently activated BK currents in mASMCs but not in mBSMCs. The abundant expression of BKγ1 in mBSMCs extensively facilitates BK channel activity to keep the resting membrane potential at negative values and prevents contraction under physiological conditions.
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Affiliation(s)
- Sayuri Noda
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Yoshiaki Suzuki
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Wayne R Giles
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
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7
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Chiral resolution of a caged xanthone and evaluation across a broad spectrum of breast cancer subtypes. Bioorg Chem 2019; 93:103303. [DOI: 10.1016/j.bioorg.2019.103303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/15/2019] [Accepted: 09/17/2019] [Indexed: 12/29/2022]
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Haworth AS, Brackenbury WJ. Emerging roles for multifunctional ion channel auxiliary subunits in cancer. Cell Calcium 2019; 80:125-140. [PMID: 31071485 PMCID: PMC6553682 DOI: 10.1016/j.ceca.2019.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further expanding the repertoire of cellular processes governed by ion channel complexes to processes such as transcellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+, K+, Na+ and Cl- channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregulated (e.g. Cavβ, Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1, Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets. However further mechanistic understanding is required into how these subunits contribute to tumour progression before their therapeutic potential can be fully realised.
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Affiliation(s)
- Alexander S Haworth
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK.
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9
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Evans RL, Pottala JV, Nagata S, Egland KA. Longitudinal autoantibody responses against tumor-associated antigens decrease in breast cancer patients according to treatment modality. BMC Cancer 2018; 18:119. [PMID: 29386014 PMCID: PMC5793406 DOI: 10.1186/s12885-018-4022-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/23/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Metastatic breast cancer (BCa) is most often diagnosed months after completion of treatment of the primary tumor when a patient reports physical symptoms. Besides a physical examination, no other alternative recurrence screening method is recommended for routine follow-up care. Detection of autoantibodies against tumor-associated antigens (TAAs) has demonstrated promise for distinguishing healthy women from patients diagnosed with primary BCa. However, it is unknown what changes occur to patient autoantibody levels during and after treatment. METHODS Three serial blood draws were collected from 200 BCa patients: before treatment, 6 and 12 months after surgery. Patients were categorized according to treatment regimen, including surgery, chemotherapy, radiation, trastuzumab and hormonal therapies. The longitudinal samples were assayed for autoantibody responses against 32 conformation-carrying TAAs using a Luminex multiplex bead assay. RESULTS The treatment modality groups that had the greatest decrease in autoantibody response levels were radiation + hormonal therapy; radiation + chemotherapy; and radiation + hormonal therapy + chemotherapy. For these three treatment groups, autoantibody responses against 9 TAAs (A1AT, ANGPTL4, CAPC, CST2, DKK1, GFRA1, GRN, LGALS3 and LRP10) were significantly reduced at 12 months after surgery compared to before treatment. One TAA, GRP78, had a significantly increased autoantibody response after 12 months. CONCLUSIONS Single treatment regimens alone did not significantly alter autoantibodies levels against the studied TAAs. Radiation treatment was the common denominator of the three most affected groups for significant changes in autoantibody response levels.
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Affiliation(s)
- Rick L Evans
- Cancer Biology Research Center, Sanford Research, Sioux Falls, SD, USA
| | - James V Pottala
- Sanford School of Medicine, University of South Dakota, 2301 East 60th Street North, Sioux Falls, SD, 57104, USA
| | - Satoshi Nagata
- Center for Drug Design Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki-City, Osaka, 5670085, Japan
| | - Kristi A Egland
- Cancer Biology Research Center, Sanford Research, Sioux Falls, SD, USA. .,Sanford School of Medicine, University of South Dakota, 2301 East 60th Street North, Sioux Falls, SD, 57104, USA.
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10
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Pan Q, Zhou R, Su M, Wu X, Li R. Clinical biocharacterization of immunophenotype in hepatocellular carcinoma patients. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2017; 10:7670-7673. [PMID: 31966612 PMCID: PMC6965218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/24/2017] [Indexed: 06/10/2023]
Abstract
In current observations, we investigated the clinical immunophenotypes in liver cells to assess the metastasic predisposition in advance hepatocellular carcinoma patients. In method, we harvested the clinically diagnosed data from 8 liver cancer subjects. Definitely, all patients were received standard chemotherapeutics when being confirmed as advanced liver cancer via clinical diagnosis. In parallel, biopsy liver samples were subjected to histopathological and immunoblotting assays. Representatively, clinical laboratory results showed that blood parameters resulted in notable elevations of aminotransferases (ALT, AST), hepatitis B e antibody (HBeAb), alpha-fetoprotein (APF) and carcinoembryonic antigen (CEA). In addition, immunoassays exhibited significant hepatocellular expressions of Ki-67 (cell proliferation), CD34 (angiogenesis), as well as strong production of CK8, CK10 (metastasis) in liver cells, as revealed in both the immunostaining and Western blotting analyses. Collectively, the present clinical findings elucidate that the metastasis of hepatocellular carcinoma relates to unregulated cell proliferation and angiogenesis. In particular, current representative immunophenotypes may be served as potential biomarkers for screening metastasis of advanced liver cancer.
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Affiliation(s)
- Qijin Pan
- Department of Oncology, Guigang City People’s Hospital, The Eighth Affiliated Hospital of Guangxi Medical UniversityGuigang, Guangxi, PR China
| | - Rui Zhou
- Department of Hepatobiliary Surgery, Guigang City People’s Hospital, The Eighth Affiliated Hospital of Guangxi Medical UniversityGuigang, Guangxi, PR China
| | - Min Su
- Faculty of Basic Medicine Science, Guilin Medical UniversityGuilin, Guangxi, PR China
| | - Xinmou Wu
- College of Pharmacy, Guangxi Medical UniversityNanning, Guangxi, PR China
| | - Rong Li
- Key Laboratory of Tumor Immunology and Microenvironmental Regulation, Guilin Medical UniversityGuilin, Guangxi, PR China
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Knockout of the LRRC26 subunit reveals a primary role of LRRC26-containing BK channels in secretory epithelial cells. Proc Natl Acad Sci U S A 2017; 114:E3739-E3747. [PMID: 28416688 DOI: 10.1073/pnas.1703081114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Leucine-rich-repeat-containing protein 26 (LRRC26) is the regulatory γ1 subunit of Ca2+- and voltage-dependent BK-type K+ channels. BK channels that contain LRRC26 subunits are active near normal resting potentials even without Ca2+, suggesting they play unique physiological roles, likely limited to very specific cell types and cellular functions. By using Lrrc26 KO mice with a β-gal reporter, Lrrc26 promoter activity is found in secretory epithelial cells, especially acinar epithelial cells in lacrimal and salivary glands, and also goblet and Paneth cells in intestine and colon, although absent from neurons. We establish the presence of LRRC26 protein in eight secretory tissues or tissues with significant secretory epithelium and show that LRRC26 protein coassembles with the pore-forming BK α-subunit in at least three tissues: lacrimal gland, parotid gland, and colon. In lacrimal, parotid, and submandibular gland acinar cells, LRRC26 KO shifts BK gating to be like α-subunit-only BK channels. Finally, LRRC26 KO mimics the effect of SLO1/BK KO in reducing [K+] in saliva. LRRC26-containing BK channels are competent to contribute to resting K+ efflux at normal cell membrane potentials with resting cytosolic Ca2+ concentrations and likely play a critical physiological role in supporting normal secretory function in all secretory epithelial cells.
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Latorre R, Castillo K, Carrasquel-Ursulaez W, Sepulveda RV, Gonzalez-Nilo F, Gonzalez C, Alvarez O. Molecular Determinants of BK Channel Functional Diversity and Functioning. Physiol Rev 2017; 97:39-87. [DOI: 10.1152/physrev.00001.2016] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Large-conductance Ca2+- and voltage-activated K+ (BK) channels play many physiological roles ranging from the maintenance of smooth muscle tone to hearing and neurosecretion. BK channels are tetramers in which the pore-forming α subunit is coded by a single gene ( Slowpoke, KCNMA1). In this review, we first highlight the physiological importance of this ubiquitous channel, emphasizing the role that BK channels play in different channelopathies. We next discuss the modular nature of BK channel-forming protein, in which the different modules (the voltage sensor and the Ca2+ binding sites) communicate with the pore gates allosterically. In this regard, we review in detail the allosteric models proposed to explain channel activation and how the models are related to channel structure. Considering their extremely large conductance and unique selectivity to K+, we also offer an account of how these two apparently paradoxical characteristics can be understood consistently in unison, and what we have learned about the conduction system and the activation gates using ions, blockers, and toxins. Attention is paid here to the molecular nature of the voltage sensor and the Ca2+ binding sites that are located in a gating ring of known crystal structure and constituted by four COOH termini. Despite the fact that BK channels are coded by a single gene, diversity is obtained by means of alternative splicing and modulatory β and γ subunits. We finish this review by describing how the association of the α subunit with β or with γ subunits can change the BK channel phenotype and pharmacology.
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Affiliation(s)
- Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Willy Carrasquel-Ursulaez
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Romina V. Sepulveda
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Fernando Gonzalez-Nilo
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Osvaldo Alvarez
- Centro Interdisciplinario de Neurociencia de Valparaíso and Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Universidad Andres Bello, Facultad de Ciencias Biologicas, Center for Bioinformatics and Integrative Biology, Avenida Republica 239, Santiago, Chile and Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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13
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Jalali A, Amirian ES, Bainbridge MN, Armstrong GN, Liu Y, Tsavachidis S, Jhangiani SN, Plon SE, Lau CC, Claus EB, Barnholtz-Sloan JS, Il'yasova D, Schildkraut J, Ali-Osman F, Sadetzki S, Johansen C, Houlston RS, Jenkins RB, Lachance D, Olson SH, Bernstein JL, Merrell RT, Wrensch MR, Davis FG, Lai R, Shete S, Aldape K, Amos CI, Muzny DM, Gibbs RA, Melin BS, Bondy ML. Targeted sequencing in chromosome 17q linkage region identifies familial glioma candidates in the Gliogene Consortium. Sci Rep 2015; 5:8278. [PMID: 25652157 PMCID: PMC4317686 DOI: 10.1038/srep08278] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 01/06/2015] [Indexed: 12/30/2022] Open
Abstract
Glioma is a rare, but highly fatal, cancer that accounts for the majority of malignant primary brain tumors. Inherited predisposition to glioma has been consistently observed within non-syndromic families. Our previous studies, which involved non-parametric and parametric linkage analyses, both yielded significant linkage peaks on chromosome 17q. Here, we use data from next generation and Sanger sequencing to identify familial glioma candidate genes and variants on chromosome 17q for further investigation. We applied a filtering schema to narrow the original list of 4830 annotated variants down to 21 very rare (<0.1% frequency), non-synonymous variants. Our findings implicate the MYO19 and KIF18B genes and rare variants in SPAG9 and RUNDC1 as candidates worthy of further investigation. Burden testing and functional studies are planned.
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Affiliation(s)
- Ali Jalali
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas
| | - E. Susan Amirian
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Matthew N. Bainbridge
- Codified Genomics, LLC, Houston Texas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Georgina N. Armstrong
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Yanhong Liu
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Spyros Tsavachidis
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | | | - Sharon E. Plon
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Ching C. Lau
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Elizabeth B. Claus
- Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut
- Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts
| | - Jill S. Barnholtz-Sloan
- Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Dora Il'yasova
- Department of Epidemiology and Biostatistics, Georgia State University School of Public Health, Atlanta, Georgia
- Cancer Control and Prevention Program, Department of Community and Family Medicine, Duke University Medical Center, Durham, North Carolina
| | - Joellen Schildkraut
- Cancer Control and Prevention Program, Department of Community and Family Medicine, Duke University Medical Center, Durham, North Carolina
| | - Francis Ali-Osman
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Siegal Sadetzki
- Cancer and Radiation Epidemiology Unit, Gertner Institute, Chaim Sheba Medical Center, Tel Hashomer
- Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Christoffer Johansen
- Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark
- Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Richard S. Houlston
- Section of Cancer Genetics, Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Robert B. Jenkins
- Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Rochester, Minnesota
| | - Daniel Lachance
- Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Rochester, Minnesota
| | - Sara H. Olson
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Jonine L. Bernstein
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ryan T. Merrell
- Department of Neurology, NorthShore University HealthSystem, Evanston, Illinois
| | - Margaret R. Wrensch
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, California
| | - Faith G. Davis
- Department of Public Health Services, University of Alberta, Edmonton, Alberta, Canada
| | - Rose Lai
- Departments of Neurology, Neurosurgery, and Preventive Medicine, The University of Southern California Keck School of Medicine, Los Angeles, California
| | - Sanjay Shete
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kenneth Aldape
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Christopher I. Amos
- Department of Community and Family Medicine, Department of Genetics, Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth; Hanover, New Hampshire
| | - Donna M. Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Richard A. Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Beatrice S. Melin
- Department of Radiation Sciences Oncology, Umeå University, Umeå, Sweden
| | - Melissa L. Bondy
- Department of Pediatrics, Division of Hematology-Oncology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas
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14
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The human cell surfaceome of breast tumors. BIOMED RESEARCH INTERNATIONAL 2013; 2013:976816. [PMID: 24195083 PMCID: PMC3781997 DOI: 10.1155/2013/976816] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/22/2013] [Indexed: 12/04/2022]
Abstract
Introduction. Cell surface proteins are ideal targets for cancer therapy and diagnosis. We have identified a set of more than 3700 genes that code for transmembrane proteins believed to be at human cell surface. Methods. We used a high-throuput qPCR system for the analysis of 573 cell surface protein-coding genes in 12 primary breast tumors, 8 breast cell lines, and 21 normal human tissues including breast. To better understand the role of these genes in breast tumors, we used a series of bioinformatics strategies to integrates different type, of the datasets, such as KEGG, protein-protein interaction databases, ONCOMINE, and data from, literature. Results. We found that at least 77 genes are overexpressed in breast primary tumors while at least 2 of them have also a restricted expression pattern in normal tissues. We found common signaling pathways that may be regulated in breast tumors through the overexpression of these cell surface protein-coding genes. Furthermore, a comparison was made between the genes found in this report and other genes associated with features clinically relevant for breast tumorigenesis. Conclusions. The expression profiling generated in this study, together with an integrative bioinformatics analysis, allowed us to identify putative targets for breast tumors.
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15
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Watson AP, Evans RL, Egland KA. Multiple functions of sushi domain containing 2 (SUSD2) in breast tumorigenesis. Mol Cancer Res 2012; 11:74-85. [PMID: 23131994 DOI: 10.1158/1541-7786.mcr-12-0501-t] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Routinely used therapies are not adequate to treat the heterogeneity of breast cancer, and consequently, more therapeutic targets are desperately needed. To identify novel targets, we generated a breast cancer cDNA library enriched for genes that encode membrane and secreted proteins. From this library we identified SUSD2 (Sushi Domain Containing 2), which encodes an 822-amino acid protein containing a transmembrane domain and functional domains inherent to adhesion molecules. Previous studies describe the mouse homolog, Susd2, but there are no studies on the human gene associated with breast cancer. Immunohistochemical analysis of human breast tissues showed weak or no expression of SUSD2 in normal epithelial cells, with the endothelial lining of vessels staining positive for SUSD2. However, staining was observed in pathologic breast lesions and in lobular and ductal carcinomas. SUSD2 interacts with galectin-1 (Gal-1), a 14-kDa secreted protein that is synthesized by carcinoma cells and promotes tumor immune evasion, angiogenesis, and metastasis. Interestingly, we found that localization of Gal-1 on the surface of cells is dependent on the presence of SUSD2. Various phenotype assays indicate that SUSD2 increases the invasion of breast cancer cells and contributes to a potential immune evasion mechanism through induction of apoptosis of Jurkat T cells. Using a syngeneic mouse model, we observed accelerated tumor formation and decreased survival in mice with tumors expressing Susd2. We found significantly fewer CD4 tumor infiltrating lymphocytes in mice with tumors expressing Susd2. Together, our findings provide evidence that SUSD2 may represent a promising therapeutic target for breast cancer.
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Affiliation(s)
- Allison P Watson
- Cancer Biology Research Center, Sanford Research, Sanford School of Medicine of The University of South Dakota, 2301 East 60th Street North, Sioux Falls, SD 57104.
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16
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BK potassium channel modulation by leucine-rich repeat-containing proteins. Proc Natl Acad Sci U S A 2012; 109:7917-22. [PMID: 22547800 DOI: 10.1073/pnas.1205435109] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Molecular diversity of ion channel structure and function underlies variability in electrical signaling in nerve, muscle, and nonexcitable cells. Regulation by variable auxiliary subunits is a major mechanism to generate tissue- or cell-specific diversity of ion channel function. Mammalian large-conductance, voltage- and calcium-activated potassium channels (BK, K(Ca)1.1) are ubiquitously expressed with diverse functions in different tissues or cell types, consisting of the pore-forming, voltage- and Ca(2+)-sensing α-subunits (BKα), either alone or together with the tissue-specific auxiliary β-subunits (β1-β4). We recently identified a leucine-rich repeat (LRR)-containing membrane protein, LRRC26, as a BK channel auxiliary subunit, which causes an unprecedented large negative shift (∼140 mV) in voltage dependence of channel activation. Here we report a group of LRRC26 paralogous proteins, LRRC52, LRRC55, and LRRC38 that potentially function as LRRC26-type auxiliary subunits of BK channels. LRRC52, LRRC55, and LRRC38 produce a marked shift in the BK channel's voltage dependence of activation in the hyperpolarizing direction by ∼100 mV, 50 mV, and 20 mV, respectively, in the absence of calcium. They along with LRRC26 show distinct expression in different human tissues: LRRC26 and LRRC38 mainly in secretory glands, LRRC52 in testis, and LRRC55 in brain. LRRC26 and its paralogs are structurally and functionally distinct from the β-subunits and we designate them as a γ family of the BK channel auxiliary proteins, which potentially regulate the channel's gating properties over a spectrum of different tissues or cell types.
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17
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Almassy J, Begenisich T. The LRRC26 protein selectively alters the efficacy of BK channel activators. Mol Pharmacol 2011; 81:21-30. [PMID: 21984254 DOI: 10.1124/mol.111.075234] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Large conductance, Ca(2+)-activated K channel proteins are involved in a wide range of physiological activities, so there is considerable interest in the pharmacology of large conductance calcium-activated K (BK) channels. One potent activator of BK channels is mallotoxin (MTX), which produces a very large hyperpolarizing shift of the voltage gating of heterologously expressed BK channels and causes a dramatic increase in the activity of BK channels in human smooth muscle cells. However, we found that MTX shifted the steady-state activation of BK channels in native parotid acinar cells by only 6 mV. This was not because the parotid BK isoform (parSlo) is inherently insensitive to MTX as MTX shifted the activation of heterologously expressed parSlo channels by 70 mV. Even though MTX had a minimal effect on steady-state activation of parotid BK channels, it produced an approximate 2-fold speeding of the channel-gating kinetics. The BK channels in parotid acinar cells have a much more hyperpolarized voltage activation range than BK channels in most other cell types. We found that this is probably attributable to an accessory protein, LRRC26, which is expressed in parotid glands: expressed parSlo + LRRC26 channels were resistant to the actions of MTX. Another class of BK activators is the benzimidazalones that includes 1,3-dihydro-1-(2-hydroxy-5-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS-1619). Although the LRRC26 accessory protein strongly inhibited the ability of MTX to activate BK channels, we found that it had only a small effect on the action of NS-1619 on BK channels. Thus, the LRRC26 BK channel accessory protein selectively alters the pharmacology of BK channels.
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Affiliation(s)
- Janos Almassy
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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18
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Liu XF, Xiang L, Zhang Y, Becker KG, Bera TK, Pastan I. CAPC negatively regulates NF-κB activation and suppresses tumor growth and metastasis. Oncogene 2011; 31:1673-82. [PMID: 21822313 PMCID: PMC3213307 DOI: 10.1038/onc.2011.355] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CAPC, also known as LRRC26, is expressed in normal prostate and salivary gland. We developed a mAb to CAPC and used it to characterize the protein and study its function. CAPC protein was detected in normal prostate and salivary gland, in several human breast cancer cell lines and in the prostate cancer cell line LNCaP. Knockdown of CAPC by siRNA in LNCaP cells enhanced anchorage-independent growth in soft agar. Conversely, overexpression of CAPC in MDA-231 breast cancer cells and A431 epidermoid cancer cells inhibited growth in soft agar and tumorigenesis in nude mice, and suppressed the metastasis of MDA-231 cells to the lung. Overexpression of CAPC downregulated NF-κB activity and its target genes, including GM-CSF (CSF2), CXCL1, IL8 and LTB1. It also suppressed genes encoding the serine protease mesotrypsin (PRSS3) and cystatin SN (CST1). CAPC expressing tumors showed a decrease in the number of proliferating cells and a large increase in ECM. The role of CAPC in the suppression of tumor growth and metastasis may be through its alteration of the tumor microenvironment.
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Affiliation(s)
- X-F Liu
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264, USA
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19
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LRRC26 auxiliary protein allows BK channel activation at resting voltage without calcium. Nature 2010; 466:513-6. [PMID: 20613726 DOI: 10.1038/nature09162] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 05/07/2010] [Indexed: 11/08/2022]
Abstract
Large-conductance, voltage- and calcium-activated potassium (BK, or K(Ca)1.1) channels are ubiquitously expressed in electrically excitable and non-excitable cells, either as alpha-subunit (BKalpha) tetramers or together with tissue specific auxiliary beta-subunits (beta1-beta4). Activation of BK channels typically requires coincident membrane depolarization and elevation in free cytosolic Ca(2+) concentration ([Ca(2+)](i)), which are not physiological conditions for most non-excitable cells. Here we present evidence that in non-excitable LNCaP prostate cancer cells, BK channels can be activated at negative voltages without rises in [Ca(2+)](i) through their complex with an auxiliary protein, leucine-rich repeat (LRR)-containing protein 26 (LRRC26). LRRC26 modulates the gating of a BK channel by enhancing the allosteric coupling between voltage-sensor activation and the channel's closed-open transition. This finding reveals a novel auxiliary protein of a voltage-gated ion channel that gives an unprecedentedly large negative shift ( approximately -140 mV) in voltage dependence and provides a molecular basis for activation of BK channels at physiological voltages and calcium levels in non-excitable cells.
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20
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Anaganti S, Hansen JK, Ha D, Hahn Y, Chertov O, Pastan I, Bera TK. Non-AUG translational initiation of a short CAPC transcript generating protein isoform. Biochem Biophys Res Commun 2009; 380:508-13. [PMID: 19250639 DOI: 10.1016/j.bbrc.2009.01.089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/20/2009] [Indexed: 01/02/2023]
Abstract
CAPC (also known as LRRC26) is a new gene with restricted expression in normal tissues, and with expression in many cancers and cancer cell lines. We have identified and characterized a short-transcript of CAPC (S-CAPC). The nucleotide sequence analysis of CAPC mRNA showed that the transcription for S-CAPC starts at position +610 on the L-CAPC transcript. Interestingly, no translation initiation codon 'AUG' is present in this transcript. To determine if a non-AUG start site is utilized, the S-CAPC sequence was cloned into an expression vector with C-terminal myc and histidine tags, and transfected into 293T cells. Western blot and MALDI-TOF MS analysis on purified S-CAPC gave two distinct peaks at approximately 7.5 kDa. N-terminal amino acid sequencing of the purified 7.5 kDa protein product indicated that translation starts at the codon for cysteine on the S
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Affiliation(s)
- Suresh Anaganti
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Room 5110, Bethesda, MD 20892-4264, USA
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21
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Bera T, Lee B. Mining of Genome Sequence Databases to Identify New Targets for Prostate and Breast Cancer Therapy. Genomics 2008. [DOI: 10.3109/9781420067064-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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23
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Immunotoxin and Taxol synergy results from a decrease in shed mesothelin levels in the extracellular space of tumors. Proc Natl Acad Sci U S A 2007; 104:17099-104. [PMID: 17940013 DOI: 10.1073/pnas.0708101104] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recombinant immunotoxins are chimeric proteins composed of the Fv portion of a tumor-specific antibody fused to a toxin. SS1P (CAT-5001) is an immunotoxin composed of an antimesothelin Fv fused to a 38-kDa portion of Pseudomonas exotoxin A. Immunotoxins have been shown to be active in lymphomas and leukemias, but are much less active against solid tumors. We recently reported that Taxol and other chemotherapeutic agents show striking synergistic antitumor activity in mice when immunotoxin SS1P, which targets the mesothelin antigen on solid tumors, is given with Taxol. Using a pair of Taxol-sensitive and Taxol-resistant KB tumors equally sensitive to immunotoxin SS1P, we examined the mechanism of synergy. We show that synergy is only observed with Taxol-sensitive tumors, ruling out an effect of Taxol on endothelial cells. We also show that the KB tumors have high levels of shed mesothelin in their extracellular space; these levels increase with tumor size and, after Taxol treatment, dramatically fall in the drug-sensitive but not the drug-resistant tumors. Because the mesothelin levels in the tumor exceed the levels of SS1P in the tumor, and because shed mesothelin is being continuously released into the circulation at a high rate, we propose that synergy is due to the Taxol-induced fall in shed antigen levels.
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Oriolo AS, Wald FA, Ramsauer VP, Salas PJI. Intermediate filaments: a role in epithelial polarity. Exp Cell Res 2007; 313:2255-64. [PMID: 17425955 PMCID: PMC1986643 DOI: 10.1016/j.yexcr.2007.02.030] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 02/19/2007] [Accepted: 02/22/2007] [Indexed: 11/24/2022]
Abstract
Intermediate filaments have long been considered mechanical components of the cell that provide resistance to deformation stress. Practical experimental problems, including insolubility, lack of good pharmacological antagonists, and the paucity of powerful genetic models have handicapped the research of other functions. In single-layered epithelial cells, keratin intermediate filaments are cortical, either apically polarized or apico-lateral. This review analyzes phenotypes of genetic manipulations of simple epithelial cell keratins in mice and Caenorhabditis elegans that strongly suggest a role of keratins in apico-basal polarization and membrane traffic. Published evidence that intermediate filaments can act as scaffolds for proteins involved in membrane traffic and signaling is also discussed. Such a scaffolding function would generate a highly polarized compartment within the cytoplasm of simple epithelial cells. While in most cases mechanistic explanations for the keratin-null or overexpression phenotypes are still missing, it is hoped that investigators will be encouraged to study these as yet poorly understood functions of intermediate filaments.
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Affiliation(s)
- Andrea S Oriolo
- Department of Cell Biology and Anatomy, University of Miami, Miller School of Medicine, 1600 NW 10th Ave.-RMSB, Miami, FL 33136, USA
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25
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Lembessis P, Msaouel P, Halapas A, Sourla A, Panteleakou Z, Pissimissis N, Milathianakis C, Bogdanos J, Papaioannou A, Maragoudakis E, Dardoufas C, Dimopoulos T, Koutsilieris M. Combined androgen blockade therapy can convert RT-PCR detection of prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) transcripts from positive to negative in the peripheral blood of patients with clinically localized prostate cancer and increase biochemical failure-free survival after curative therapy. ACTA ACUST UNITED AC 2007; 45:1488-94. [DOI: 10.1515/cclm.2007.301] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractClin Chem Leb Med 2007;45:1488–94.
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