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Wang Y, Zheng S, Han J, Li N, Ji R, Li X, Han C, Zhao W, Zhang L. LINC00629 protects osteosarcoma cell from ER stress-induced apoptosis and facilitates tumour progression by elevating KLF4 stability. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2022; 41:354. [PMID: 36539799 PMCID: PMC9764730 DOI: 10.1186/s13046-022-02569-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Escaping from ER stress-induced apoptosis plays an important role in the progression of many tumours. However, its molecular mechanism in osteosarcoma remains incompletely understood. METHODS The molecular mechanism was investigated using RNA sequencing, qRT-PCR and Western blot assays. The relationship between LINC00629 and KLF4 was investigated using RNA pulldown and ubiquitylation assays. The transcriptional regulation of laminin subunit alpha 4 (LAMA4) by KLF4 was identified using bioinformatic analysis, a luciferase assay, and a chromatin immunoprecipitation assay. RESULTS Here, we demonstrated that LINC00629 was increased under ER stress treatment. Elevated LINC00629 inhibited ER stress-induced osteosarcoma cell apoptosis and promoted clonogenicity and migration in vitro and in vivo. Further mechanistic studies indicated that LINC00629 interacted with KLF4 and suppressed its degradation, which led to a KLF4 increase in osteosarcoma. In addition, we also found that KLF4 upregulated LAMA4 expression by directly binding to its promoter and that LINC00629 inhibited ER stress-induced apoptosis and facilitated osteosarcoma cell clonogenicity and metastasis by activating the KLF4-LAMA4 pathway. CONCLUSION Collectively, our data indicate that LINC00629 is a critical long noncoding RNA (lncRNA) induced by ER stress and plays an oncogenic role in osteosarcoma cell by activating the KLF4-LAMA4 axis.
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Affiliation(s)
- Yuan Wang
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
| | - Shuo Zheng
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
| | - Jian Han
- grid.411971.b0000 0000 9558 1426Department of Orthopedics, The Third People’s Hospital of Dalian, Dalian Medical University, Dalian, Liaoning 116033 People’s Republic of China
| | - Na Li
- grid.411971.b0000 0000 9558 1426National-Local Joint Engineering Research Center for Drug-Research and Development (R&D) of Neurodegenerative Diseases, Dalian Medical University, Dalian, 116044 People’s Republic of China
| | - Renchen Ji
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
| | - Xiaodong Li
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
| | - Chuanchun Han
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
| | - Wenzhi Zhao
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
| | - Lu Zhang
- grid.411971.b0000 0000 9558 1426The Second Affiliated Hospital & Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044 People’s Republic of China
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Ma X, Li Y, Zhao B. Ribosomal protein L5 (RPL5)/ E2F transcription factor 1 (E2F1) signaling suppresses breast cancer progression via regulating endoplasmic reticulum stress and autophagy. Bioengineered 2022; 13:8076-8086. [PMID: 35293275 PMCID: PMC9161874 DOI: 10.1080/21655979.2022.2052672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 02/08/2023] Open
Abstract
Endoplasmic reticulum stress (ERS) is associated with breast cancer progression. However, the potential role of ribosomal protein L5 (RPL5) on ERS in breast cancer remains unclear. This study aimed to determine the role of RPL5/E2F transcription factor 1 (E2F1) in breast cancer. It was found that RPL5 was downregulated in breast cancer cells and tissues. Additionally, overexpression of RPL5 inhibited cell proliferation. Moreover, the levels of ERS and autophagy markers were estimated using western blotting. Overexpression of RPL5 induced ERS and suppressed autophagy. Additionally, RPL5 downregulated E2F1, which was overexpressed in breast cancer cells. However, E2F1 knockdown promoted the transcriptional activation of glucose regulated protein 78 (GRP78), suppressed ERS response, and promoted autophagy. Rescue assays indicated that the effects of RPL5 on ERS and autophagy were abolished by E2F1. Taken together, RPL5 inhibited the growth of breast cancer cells by modulating ERS and autophagy via the regulation of E2F1. These findings suggest that RPL5 has a tumor-suppressive effect in breast cancer.
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Affiliation(s)
- Xiaoping Ma
- Breast Internal Medicine Department, The 3rd Affiliated Teaching Hospital of XinJiang Medical University(Affiliated Tumor Hospital), Urumqi, China
| | - Yan Li
- Breast Internal Medicine Department, The 3rd Affiliated Teaching Hospital of XinJiang Medical University(Affiliated Tumor Hospital), Urumqi, China
| | - Bing Zhao
- Breast Internal Medicine Department, The 3rd Affiliated Teaching Hospital of XinJiang Medical University(Affiliated Tumor Hospital), Urumqi, China
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3
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Soto-Moreno EJ, Balboula A, Spinka C, Rivera RM. Serum supplementation during bovine embryo culture affects their development and proliferation through macroautophagy and endoplasmic reticulum stress regulation. PLoS One 2021; 16:e0260123. [PMID: 34882691 PMCID: PMC8659681 DOI: 10.1371/journal.pone.0260123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/02/2021] [Indexed: 11/18/2022] Open
Abstract
Serum supplementation during bovine embryo culture has been demonstrated to promote cell proliferation and preimplantation embryo development. However, these desirable outcomes, have been associated with gene expression alterations of pathways involved in macroautophagy, growth, and development at the blastocyst stage, as well as with developmental anomalies such as fetal overgrowth and placental malformations. In order to start dissecting the molecular pathways by which serum supplementation of the culture medium during the preimplantation stage promotes developmental abnormalities, we examined blastocyst morphometry, inner cell mass and trophectoderm cell allocations, macroautophagy, and endoplasmic reticulum stress. On day 5 post-insemination, > 16 cells embryos were selected and cultured in medium containing 10% serum or left as controls. Embryo diameter, inner cell mass and trophectoderm cell number, and macroautophagy were measured on day 8 blastocysts (BL) and expanded blastocysts (XBL). On day 5 and day 8, we assessed transcript level of the ER stress markers HSPA5, ATF4, MTHFD2, and SHMT2 as well as XBP1 splicing (a marker of the unfolded protein response). Serum increased diameter and proliferation of embryos when compared to the no-serum group. In addition, serum increased macroautophagy of BL when compared to controls, while the opposite was true for XBL. None of the genes analyzed was differentially expressed at any stage, except that serum decreased HSPA5 in day 5 > 16 cells stage embryos. XBP1 splicing was decreased in BL when compared to XBL, but only in the serum group. Our data suggest that serum rescues delayed embryos by alleviating endoplasmic reticulum stress and promotes development of advanced embryos by decreasing macroautophagy.
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Affiliation(s)
- Edgar Joel Soto-Moreno
- Division of Animal Sciences, University of Missouri, Columbia, MO, United States of America
| | - Ahmed Balboula
- Division of Animal Sciences, University of Missouri, Columbia, MO, United States of America
| | - Christine Spinka
- College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, United States of America
| | - Rocío Melissa Rivera
- Division of Animal Sciences, University of Missouri, Columbia, MO, United States of America
- * E-mail:
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4
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Lee J, Rho JH, Roehrl MH, Wang JY. Dermatan Sulfate Is a Potential Regulator of IgH via Interactions With Pre-BCR, GTF2I, and BiP ER Complex in Pre-B Lymphoblasts. Front Immunol 2021; 12:680212. [PMID: 34113352 PMCID: PMC8185350 DOI: 10.3389/fimmu.2021.680212] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Abstract
Dermatan sulfate (DS) and autoantigen (autoAg) complexes are capable of stimulating autoreactive CD5+ B1 cells. We examined the activity of DS on CD5+ pre-B lymphoblast NFS-25 cells. CD19, CD5, CD72, PI3K, and Fas possess varying degrees of DS affinity. The three pre-BCR components, Ig heavy chain mu (IgH), VpreB, and lambda 5, display differential DS affinities, with IgH having the strongest affinity. DS attaches to NFS-25 cells, gradually accumulates in the ER, and eventually localizes to the nucleus. DS and IgH co-localize on the cell surface and in the ER. DS associates strongly with 17 ER proteins (e.g., BiP/Grp78, Grp94, Hsp90ab1, Ganab, Vcp, Canx, Kpnb1, Prkcsh, Pdia3), which points to an IgH-associated multiprotein complex in the ER. In addition, DS interacts with nuclear proteins (Ncl, Xrcc6, Prmt5, Eftud2, Supt16h) and Lck. We also discovered that DS binds GTF2I, a required gene transcription factor at the IgH locus. These findings support DS as a potential regulator of IgH in pre-B cells at protein and gene levels. We propose a (DS•autoAg)-autoBCR dual signal model in which an autoBCR is engaged by both autoAg and DS, and, once internalized, DS recruits a cascade of molecules that may help avert apoptosis and steer autoreactive B cell fate. Through its affinity with autoAgs and its control of IgH, DS emerges as a potential key player in the development of autoreactive B cells and autoimmunity.
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Affiliation(s)
- Jongmin Lee
- Department of Molecular and Cell Biology, Boston University School of Dental Medicine, Boston, MA, United States
| | - Jung-hyun Rho
- MP Biomedicals New Zealand Limited, Auckland, New Zealand
| | - Michael H. Roehrl
- Department of Pathology and Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States
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Leclerc D, Jelinek J, Christensen KE, Issa JPJ, Rozen R. High folic acid intake increases methylation-dependent expression of Lsr and dysregulates hepatic cholesterol homeostasis. J Nutr Biochem 2020; 88:108554. [PMID: 33220403 DOI: 10.1016/j.jnutbio.2020.108554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 09/17/2020] [Accepted: 11/12/2020] [Indexed: 12/12/2022]
Abstract
Food fortification with folic acid and increased use of vitamin supplements have raised concerns about high folic acid intake. We previously showed that high folic acid intake was associated with hepatic degeneration, decreased levels of methylenetetrahydrofolate reductase (MTHFR), lower methylation potential, and perturbations of lipid metabolism. MTHFR synthesizes the folate derivative for methylation reactions. In this study, we assessed the possibility that high folic acid diets, fed to wild-type and Mthfr+/- mice, could alter DNA methylation and/or deregulate hepatic cholesterol homeostasis. Digital restriction enzyme analysis of methylation in liver revealed DNA hypomethylation of a CpG in the lipolysis-stimulated lipoprotein receptor (Lsr) gene, which is involved in hepatic uptake of cholesterol. Pyrosequencing confirmed this methylation change and identified hypomethylation of several neighboring CpG dinucleotides. Lsr expression was increased and correlated negatively with DNA methylation and plasma cholesterol. A putative binding site for E2F1 was identified. ChIP-qPCR confirmed reduced E2F1 binding when methylation at this site was altered, suggesting that it could be involved in increasing Lsr expression. Expression of genes in cholesterol synthesis, transport or turnover (Abcg5, Abcg8, Abcc2, Cyp46a1, and Hmgcs1) was perturbed by high folic acid intake. We also observed increased hepatic cholesterol and increased expression of genes such as Sirt1, which might be involved in a rescue response to restore cholesterol homeostasis. Our work suggests that high folic acid consumption disturbs cholesterol homeostasis in liver. This finding may have particular relevance for MTHFR-deficient individuals, who represent ~10% of many populations.
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Affiliation(s)
- Daniel Leclerc
- Departments of Human Genetics and Pediatrics, McGill University, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
| | - Jaroslav Jelinek
- Fels Institute for Cancer Research and Molecular Biology, Temple University, Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Karen E Christensen
- Departments of Human Genetics and Pediatrics, McGill University, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
| | - Jean-Pierre J Issa
- Fels Institute for Cancer Research and Molecular Biology, Temple University, Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Rima Rozen
- Departments of Human Genetics and Pediatrics, McGill University, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada.
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Barez SR, Atar AM, Aghaei M. Mechanism of inositol-requiring enzyme 1-alpha inhibition in endoplasmic reticulum stress and apoptosis in ovarian cancer cells. J Cell Commun Signal 2020; 14:403-415. [PMID: 32200504 DOI: 10.1007/s12079-020-00562-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 03/09/2020] [Indexed: 02/06/2023] Open
Abstract
IRE1α endonuclease is a key regulator of endoplasmic reticulum (ER) stress that controls cell survival/apoptosis in cancers. Inhibition of IRE1α endonuclease leads to decreased splice XBP1 which decreases cell proliferation and increases cell death in cancer cells. Therefore, this study investigated the effects and mechanism of STF-083010 (an IRE1α inhibitor) on the cell growth/apoptosis of ovarian malignant cells via the XBP1-CHOP-Bim pathway following the induction of ER stress (ERS). ERS in OVCAR3 and SKOV3 cells was measured using Thioflavin T staining. The expression of ER stress response genes was evaluated by QRT-PCR. The levels of XBP1(s), PERK, phospho-PERK, p-PP2A, ATF4, BIP/GRP78, CHOP, and Bim proteins were evaluated using western blotting. Cell viability and apoptosis in STF-083010 and Tunicamycin (Tm) co-treated cells were assessed using BrdU, MTT, Annexin V-FITC/PI staining, and caspases-12 and -3 activity assays. The results showed increased XBP1, CHOP, and ATF-4 mRNA expression levels as well as high protein aggregation in STF-083010 and Tm co-treated cells. The IRE1α inhibitor down-regulated sXBP1 and BIP proteins, while XBP-1, p-PERK, ATF-4, CHOP, and Bim proteins were up-regulated. STF-083010 reduced cell proliferation and induced apoptosis through the activation of caspases-12 and -3 and Bax/Bcl-2 protein expression. In summary, the present data revealed the effects of STF-083010 in ER stress and apoptosis as well as signaling via XBP1/CHOP/Bim mediators. Thus, STF-083010 is proposed as a new target for the control of ERS in ovarian cancer cells.
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Affiliation(s)
- Shekufe Rezghi Barez
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Ahmad Movahedian Atar
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahmoud Aghaei
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
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7
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Pan TJ, Li LX, Zhang JW, Yang ZS, Shi DM, Yang YK, Wu WZ. Antimetastatic Effect of Fucoidan-Sargassum against Liver Cancer Cell Invadopodia Formation via Targeting Integrin αVβ3 and Mediating αVβ3/Src/E2F1 Signaling. J Cancer 2019; 10:4777-4792. [PMID: 31598149 PMCID: PMC6775528 DOI: 10.7150/jca.26740] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/06/2019] [Indexed: 12/25/2022] Open
Abstract
Background: Fucoidan is a fucose-enriched, sulfated polysaccharide found in brown algae; in recent years, this polysaccharide has been found to exert several biological effects, including antitumor effects, such as antiproliferation, activating apoptosis, and anti-angiogenesis of cancer cells. However, the antimetastatic effect of fucoidan and the related targeting receptors remain unknown. In the present study, we examined the inhibition of invadopodia formation and underlying mechanism of fucoidan on human liver cancer cells. Methods: We used 98% purified fucoidan from Sargassum species to treat the hepatocellular carcinoma (HCC) cells SMMC-7721, Huh7 and HCCLM3 in vitro and the HCCLM3 cell line in vivo. The HCC cells were cultured with various concentrations of Fucoidan-Sargassum (0-30 mg/mL). Migration, invasion and wound healing assays were performed to determine the antimetastatic effect of fucoidan on the HCC cells. Western blot analysis and immunofluorescence staining were conducted to determine the expression levels of invadopodia formation-regulating proteins and the targeting membrane receptor proteins. Results: Fucoidan-Sargassum inhibited the migration and invasion of HCC SMMC-7721, Huh7 and HCCLM3 cells in a dose-dependent manner. In the HCCLM3 cells, Fucoidan-Sargassum also decreased the expression levels of invadopodia-related proteins including Src, Cortactin, N-WASP, ARP3, CDC42, MMP2, MT1-MMP, and the targeting receptors integrin αV and β3 in a dose-dependent manner. Fucoidan-Sargassum also increased the levels of endoplasmic reticulum-related proteins, including GRP78, IRE1, SPARC, and the type IV collagen receptor proteins integrin α1 and β1. In vivo, Fucoidan-Sargassum reduced the size of liver tumors and decreased the number of lung metastatic foci in nude mice with hepatocellular carcinoma xenografts. Conclusion: These findings indicate that Fucoidan-Sargassum has an antimetastatic effect on SMMC-7721, Huh7 and HCCLM3 liver cancer cells, and the underlying mechanism involves targeting ITGαVβ3 and mediating the ITGαVβ3/SRC/E2F1 signaling pathway. These results suggest that Fucoidan-Sargassum may be a promising therapeutic antimetastatic compound in the development of a metastasis-preventive drug for treating liver cancer.
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Affiliation(s)
- Ting-Jia Pan
- Department of Traditional Chinese Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Li-Xin Li
- Liver Cancer Institute, Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032, China
| | - Jia-Wei Zhang
- Department of Traditional Chinese Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Zhao-Shuo Yang
- Department of Traditional Chinese Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Dong-Min Shi
- Liver Cancer Institute, Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032, China
| | - Yun-Ke Yang
- Department of Traditional Chinese Medicine, Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Wei-Zhong Wu
- Liver Cancer Institute, Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032, China
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8
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Luo J, Xia Y, Yin Y, Luo J, Liu M, Zhang H, Zhang C, Zhao Y, Yang L, Kong L. ATF4 destabilizes RET through nonclassical GRP78 inhibition to enhance chemosensitivity to bortezomib in human osteosarcoma. Am J Cancer Res 2019; 9:6334-6353. [PMID: 31534554 PMCID: PMC6735522 DOI: 10.7150/thno.36818] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 07/29/2019] [Indexed: 12/15/2022] Open
Abstract
Rationale: Activating transcription factor 4 (ATF4) is a central regulator of the cellular stress response and reduces tumor burden by controlling the expression of target genes implicated in the induction of apoptosis. Evidence shows ATF4 activation is responsible for proteasome inhibitor bortezomib (BTZ)-induced osteosarcoma (OS) cell death. However, it remains unclear how such suppressive function is impaired during prolonged therapeutic interventions. Methods: Stable cells and in vivo xenograft models were generated to reveal the essential role of ATF4 in cell apoptosis and tumor growth. Fluorescence in situ hybridization (FISH) and immunohistochemistry were employed to detect the expression and significance of ATF4 in the specimens from osteosarcoma patients. Biochemical differences between chemoresistant and chemosensitive cancer cells were determined by proliferation, apoptosis, real-time PCR, immunoblotting and immunofluorescence. Promoter activity was analysed using the luciferase reporter assay. Immunoprecipitation was used to explore the interaction of proteins with other proteins or DNAs. Results: ATF4 significantly inhibited OS tumorigenesis, whereas knockdown of ATF4 prevented the antitumor effects of BTZ. Normal osteoblasts are supposed to preferentially express ATF4, but ATF4 silencing was detected in both OS clinical samples and BTZ-resistant sublines (OS/BTZ). We found that ATF4 downregulation was tightly linked to the aberrant expression of RET, primarily due to RET stabilization in OS/BTZ cells. Loss of RET upregulated ATF4 and potentiated the apoptotic response to BTZ. ATF4 recognized the TK domain of RET by recruiting its transactivated E3 ligase Cbl-c to accelerate RET proteasomal turnover, which in turn prevented BTZ resistance. In contrast, the chaperone GRP78 bound to RET and interfered with ATF4/RET interactions, promoted RET stabilization. Intriguingly, ATF4 repressed GRP78 transcription in OS/BTZ cells via the first ERSE, instead of transactivating GRP78 in wild-type OS via classical CRE element, revealing a dual targeting of RET and GRP78 to overcome chemoresistance. Conclusion: The results uncover a crucial role for ATF4 in blocking the progression and resistance response in RET/GRP78-positive human osteosarcoma.
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9
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Sprenkle NT, Lahiri A, Simpkins JW, Meares GP. Endoplasmic reticulum stress is transmissible in vitro between cells of the central nervous system. J Neurochem 2019; 148:516-530. [PMID: 30520047 DOI: 10.1111/jnc.14642] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/09/2018] [Accepted: 11/29/2018] [Indexed: 02/02/2023]
Abstract
Improper protein folding and trafficking are common pathological events in neurodegenerative diseases that result in the toxic accumulation of misfolded proteins within the lumen of the endoplasmic reticulum (ER). While low-level stimulation of the unfolded protein response (UPR) is protective, sustained UPR activation resulting from prolonged ER stress can promote neurotoxicity. The cell-autonomous mechanisms of the UPR have been extensively characterized. However, the cell-extrinsic role of the UPR under physiological and pathological states in the CNS remains to be elucidated. To begin to address this, we evaluated if transferring conditioned media between ER-stressed astrocytes and neurons could modulate their functional characteristics. Our results indicate that ER-stressed astrocytes and neurons secrete a molecule(s) with lipid characteristics which regulates both inflammatory and ER stress responses in other astrocytes, neurons, and microglia in vitro. Initial exposure to this stress factor(s) confers resistance against subsequent ER stress to neurons. However, persistent exposure to this unidentified mediator(s) suppresses the initial protective effect and becomes cytotoxic. Overall, these findings provide insight into the cell non-autonomous influence of ER stress on cells of the central nervous system. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Neil T Sprenkle
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Anirudhya Lahiri
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - James W Simpkins
- Rockefeller Neurosciences Institute, West Virginia University School of Medicine, Morgantown, West Virginia, USA.,Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA.,Department of Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Gordon P Meares
- Department of Microbiology, Immunology and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia, USA.,Rockefeller Neurosciences Institute, West Virginia University School of Medicine, Morgantown, West Virginia, USA.,Department of Neuroscience, West Virginia University School of Medicine, Morgantown, West Virginia, USA
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TM7SF3, a novel p53-regulated homeostatic factor, attenuates cellular stress and the subsequent induction of the unfolded protein response. Cell Death Differ 2016; 24:132-143. [PMID: 27740623 DOI: 10.1038/cdd.2016.108] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 08/31/2016] [Accepted: 09/05/2016] [Indexed: 12/20/2022] Open
Abstract
Earlier reported small interfering RNA (siRNA) high-throughput screens, identified seven-transmembrane superfamily member 3 (TM7SF3) as a novel inhibitor of pancreatic β-cell death. Here we show that TM7SF3 maintains protein homeostasis and promotes cell survival through attenuation of ER stress. Overexpression of TM7SF3 inhibits caspase 3/7 activation. In contrast, siRNA-mediated silencing of TM7SF3 accelerates ER stress and activation of the unfolded protein response (UPR). This involves inhibitory phosphorylation of eukaryotic translation initiation factor 2α activity and increased expression of activating transcription factor-3 (ATF3), ATF4 and C/EBP homologous protein, followed by induction of apoptosis. This process is observed both in human pancreatic islets and in a number of cell lines. Some of the effects of TM7SF3 silencing are evident both under basal conditions, in otherwise untreated cells, as well as under different stress conditions induced by thapsigargin, tunicamycin or a mixture of pro-inflammatory cytokines (tumor necrosis factor alpha, interleukin-1 beta and interferon gamma). Notably, TM7SF3 is a downstream target of p53: activation of p53 by Nutlin increases TM7SF3 expression in a time-dependent manner, although silencing of p53 abrogates this effect. Furthermore, p53 is found in physical association with the TM7SF3 promoter. Interestingly, silencing of TM7SF3 promotes p53 activity, suggesting the existence of a negative-feedback loop, whereby p53 promotes expression of TM7SF3 that acts to restrict p53 activity. Our findings implicate TM7SF3 as a novel p53-regulated pro-survival homeostatic factor that attenuates the development of cellular stress and the subsequent induction of the UPR.
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11
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Zhang X, Trépanier V, Beaujois R, Viranaicken W, Drobetsky E, DesGroseillers L. The downregulation of the RNA-binding protein Staufen2 in response to DNA damage promotes apoptosis. Nucleic Acids Res 2016; 44:3695-712. [PMID: 26843428 PMCID: PMC4856980 DOI: 10.1093/nar/gkw057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/21/2016] [Indexed: 12/14/2022] Open
Abstract
Staufen2 (Stau2) is an RNA-binding protein involved in cell fate decision by controlling several facets of mRNA processing including localization, splicing, translation and stability. Herein we report that exposure to DNA-damaging agents that generate replicative stress such as camptothecin (CPT), 5-fluoro-uracil (5FU) and ultraviolet radiation (UVC) causes downregulation of Stau2 in HCT116 colorectal cancer cells. In contrast, other agents such as doxorubicin and ionizing radiation had no effect on Stau2 expression. Consistently, Stau2 expression is regulated by the ataxia telangiectasia and Rad3-related (ATR) signaling pathway but not by the DNA-PK or ataxia telangiectasia mutated/checkpoint kinase 2 pathways. Stau2 downregulation is initiated at the level of transcription, independently of apoptosis induction. Promoter analysis identified a short 198 bp region which is necessary and sufficient for both basal and CPT-regulated Stau2 expression. The E2F1 transcription factor regulates Stau2 in untreated cells, an effect that is abolished by CPT treatment due to E2F1 displacement from the promoter. Strikingly, Stau2 downregulation enhances levels of DNA damage and promotes apoptosis in CPT-treated cells. Taken together our results suggest that Stau2 is an anti-apoptotic protein that could be involved in DNA replication and/or maintenance of genome integrity and that its expression is regulated by E2F1 via the ATR signaling pathway.
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Affiliation(s)
- Xin Zhang
- Département de Biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Edouard Montpetit Montréal, QC H3T 1J4, Canada
| | - Véronique Trépanier
- Département de Biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Edouard Montpetit Montréal, QC H3T 1J4, Canada
| | - Remy Beaujois
- Département de Biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Edouard Montpetit Montréal, QC H3T 1J4, Canada
| | - Wildriss Viranaicken
- Département de Biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Edouard Montpetit Montréal, QC H3T 1J4, Canada
| | - Elliot Drobetsky
- Département de Médecine, Université de Montréal and Centre de Recherche, Hôpital Maisonneuve Rosemont, Montréal, Québec, H1T 2M4, Canada
| | - Luc DesGroseillers
- Département de Biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, 2900 Edouard Montpetit Montréal, QC H3T 1J4, Canada
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12
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Wang Y, Alla V, Goody D, Gupta SK, Spitschak A, Wolkenhauer O, Pützer BM, Engelmann D. Epigenetic factor EPC1 is a master regulator of DNA damage response by interacting with E2F1 to silence death and activate metastasis-related gene signatures. Nucleic Acids Res 2015; 44:117-33. [PMID: 26350215 PMCID: PMC4705687 DOI: 10.1093/nar/gkv885] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 08/24/2015] [Indexed: 12/31/2022] Open
Abstract
Transcription factor E2F1 is a key regulator of cell proliferation and apoptosis. Recently, it has been shown that aberrant E2F1 expression often detectable in advanced cancers contributes essentially to cancer cell propagation and characterizes the aggressive potential of a tumor. Conceptually, this requires a subset of malignant cells capable of evading apoptotic death through anticancer drugs. The molecular mechanism by which the pro-apoptotic activity of E2F1 is antagonized is widely unclear. Here we report a novel function for EPC1 (enhancer of polycomb homolog 1) in DNA damage protection. Depletion of EPC1 potentiates E2F1-mediated apoptosis in response to genotoxic treatment and abolishes tumor cell motility. We found that E2F1 directly binds to the EPC1 promoter and EPC1 vice versa physically interacts with bifunctional E2F1 to modulate its transcriptional activity in a target gene-specific manner. Remarkably, nuclear-colocalized EPC1 activates E2F1 to upregulate the expression of anti-apoptotic survival genes such as BCL-2 or Survivin/BIRC5 and inhibits death-inducing targets. The uncovered cooperativity between EPC1 and E2F1 triggers a metastasis-related gene signature in advanced cancers that predicts poor patient survival. These findings unveil a novel oncogenic function of EPC1 for inducing the switch into tumor progression-relevant gene expression that may help to set novel therapies.
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Affiliation(s)
- Yajie Wang
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Vijay Alla
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Deborah Goody
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Shailendra K Gupta
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany
| | - Alf Spitschak
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Olaf Wolkenhauer
- Department of Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany
| | - Brigitte M Pützer
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - David Engelmann
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
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13
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Pagliarini V, Giglio P, Bernardoni P, De Zio D, Fimia GM, Piacentini M, Corazzari M. Downregulation of E2F1 during ER stress is required to induce apoptosis. J Cell Sci 2015; 128:1166-79. [PMID: 25616897 DOI: 10.1242/jcs.164103] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The endoplasmic reticulum (ER) has recently emerged as an alternative target to induce cell death in tumours, because prolonged ER stress results in the induction of apoptosis even in chemoresistant transformed cells. Here, we show that the DNA-damage-responsive pro-apoptotic factor E2F1 is unexpectedly downregulated during the ER stress-mediated apoptotic programme. E2F1 decline is a late event during the ER response and is mediated by the two unfolded protein response (UPR) sensors ATF6 and IRE1 (also known as ERN1). Whereas ATF6 directly interacts with the E2F1 promoter, IRE1 requires the involvement of the known E2F1 modulator E2F7, through the activation of its main target Xbp-1. Importantly, inhibition of the E2F1 decrease prevents ER-stress-induced apoptosis, whereas E2F1 knockdown efficiently sensitises cells to ER stress-dependent apoptosis, leading to the upregulation of two main factors in the UPR pro-apoptotic execution phase, Puma and Noxa (also known as BBC3 and PMAIP1, respectively). Our results point to a novel key role of E2F1 in the cell survival/death decision under ER stress, and unveil E2F1 inactivation as a valuable novel potential therapeutic strategy to increase the response of tumour cells to ER stress-based anticancer treatments.
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Affiliation(s)
- Vittoria Pagliarini
- National Institute for Infectious Disease 'L. Spallanzani' IRCCS, 00149 Rome, Italy
| | - Paola Giglio
- National Institute for Infectious Disease 'L. Spallanzani' IRCCS, 00149 Rome, Italy
| | - Paolo Bernardoni
- National Institute for Infectious Disease 'L. Spallanzani' IRCCS, 00149 Rome, Italy
| | - Daniela De Zio
- Department of Biology, Unit of the Dulbecco Telethon Institute, University of Rome 'Tor Vergata', 00133 Rome, Italy Cell Stress and Survival Unit, Danish Cancer Society Research Center, Strandboulevarden 49, Copenhagen DK-2100, Denmark
| | - Gian Maria Fimia
- National Institute for Infectious Disease 'L. Spallanzani' IRCCS, 00149 Rome, Italy Department of Biological and Environmental Science and Technology (Di.S.Te.B.A.), University of Salento, 73100 Lecce, Italy
| | - Mauro Piacentini
- National Institute for Infectious Disease 'L. Spallanzani' IRCCS, 00149 Rome, Italy Cellular and Developmental Lab, Department of Biology, University of Rome 'Tor Vergata', 00133 Rome, Italy
| | - Marco Corazzari
- National Institute for Infectious Disease 'L. Spallanzani' IRCCS, 00149 Rome, Italy Cellular and Developmental Lab, Department of Biology, University of Rome 'Tor Vergata', 00133 Rome, Italy
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14
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Knoll S, Fürst K, Kowtharapu B, Schmitz U, Marquardt S, Wolkenhauer O, Martin H, Pützer BM. E2F1 induces miR-224/452 expression to drive EMT through TXNIP downregulation. EMBO Rep 2014; 15:1315-29. [PMID: 25341426 DOI: 10.15252/embr.201439392] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Malignant melanoma is highly lethal due to its aggressive invasive properties and metastatic dissemination. The transcription factor E2F1 is crucial for melanoma progression through poorly understood mechanisms. Here, we show that the miR-224/miR-452 cluster is significantly increased in advanced melanoma and invasive/metastatic cell lines that express high levels of E2F1. miR-224/miR-452 expression is directly activated by E2F1 through transactivation of the GABRE gene. Ectopic expression of miR-224/miR-452 in less aggressive cells induces EMT and cytoskeletal rearrangements and enhances migration/invasion. Conversely, miR-224/miR-452 depletion in metastatic cells induces the reversal of EMT, inhibition of motility, loss of the invasive phenotype and an absence of lung metastases in mice. We identify the metastasis suppressor TXNIP as new target of miR-224/miR-452 that induces feedback inhibition of E2F1 and show that miR-224/452-mediated downregulation of TXNIP is essential for E2F1-induced EMT and invasion. The E2F1-miR-224/452-TXNIP axis constitutes a molecular signature that predicts patient survival and may help to set novel therapies.
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Affiliation(s)
- Susanne Knoll
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Katharina Fürst
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Bhavani Kowtharapu
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Ulf Schmitz
- Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany
| | - Stephan Marquardt
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
| | - Olaf Wolkenhauer
- Systems Biology and Bioinformatics, University of Rostock, Rostock, Germany
| | - Hubert Martin
- Department of Neuropathology, University Hospital Charité, Berlin, Germany
| | - Brigitte M Pützer
- Institute of Experimental Gene Therapy and Cancer Research, Rostock University Medical Center, Rostock, Germany
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15
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Mao HZ, Ehrhardt N, Bedoya C, Gomez JA, DeZwaan-McCabe D, Mungrue IN, Kaufman RJ, Rutkowski DT, Péterfy M. Lipase maturation factor 1 (lmf1) is induced by endoplasmic reticulum stress through activating transcription factor 6α (Atf6α) signaling. J Biol Chem 2014; 289:24417-27. [PMID: 25035425 PMCID: PMC4148868 DOI: 10.1074/jbc.m114.588764] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Indexed: 11/06/2022] Open
Abstract
Lipase maturation factor 1 (Lmf1) is a critical determinant of plasma lipid metabolism, as demonstrated by severe hypertriglyceridemia associated with its mutations in mice and human subjects. Lmf1 is a chaperone localized to the endoplasmic reticulum (ER) and required for the post-translational maturation and activation of several vascular lipases. Despite its importance in plasma lipid homeostasis, the regulation of Lmf1 remains unexplored. We report here that Lmf1 expression is induced by ER stress in various cell lines and in tunicamycin (TM)-injected mice. Using genetic deficiencies in mouse embryonic fibroblasts and mouse liver, we identified the Atf6α arm of the unfolded protein response as being responsible for the up-regulation of Lmf1 in ER stress. Experiments with luciferase reporter constructs indicated that ER stress activates the Lmf1 promoter through a GC-rich DNA sequence 264 bp upstream of the transcriptional start site. We demonstrated that Atf6α is sufficient to induce the Lmf1 promoter in the absence of ER stress, and this effect is mediated by the TM-responsive cis-regulatory element. Conversely, Atf6α deficiency induced by genetic ablation or a dominant-negative form of Atf6α abolished TM stimulation of the Lmf1 promoter. In conclusion, our results indicate that Lmf1 is an unfolded protein response target gene, and Atf6α signaling is sufficient and necessary for activation of the Lmf1 promoter. Importantly, the induction of Lmf1 by ER stress appears to be a general phenomenon not restricted to lipase-expressing cells, which suggests a lipase-independent cellular role for this protein in ER homeostasis.
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Affiliation(s)
- Hui Z Mao
- From the Medical Genetics Research Institute and
| | | | - Candy Bedoya
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California 90048
| | - Javier A Gomez
- Department of Anatomy and Cell Biology and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Diane DeZwaan-McCabe
- Department of Anatomy and Cell Biology and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Imran N Mungrue
- the Department of Pharmacology and Experimental Therapeutics, Louisiana State University School of Medicine, New Orleans, Louisiana 70112
| | - Randal J Kaufman
- Degenerative Disease Research, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, and
| | - D Thomas Rutkowski
- Department of Anatomy and Cell Biology and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Miklós Péterfy
- From the Medical Genetics Research Institute and Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California 90048, the Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, California 90095
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16
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Laresgoiti U, Apraiz A, Olea M, Mitxelena J, Osinalde N, Rodriguez JA, Fullaondo A, Zubiaga AM. E2F2 and CREB cooperatively regulate transcriptional activity of cell cycle genes. Nucleic Acids Res 2013; 41:10185-98. [PMID: 24038359 PMCID: PMC3905855 DOI: 10.1093/nar/gkt821] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
E2F2 is essential for the maintenance of T lymphocyte quiescence. To identify the full set of E2F2 target genes, and to gain further understanding of the role of E2F2 in transcriptional regulation, we have performed ChIP-chip analyses across the genome of lymph node–derived T lymphocytes. Here we show that during quiescence, E2F2 binds the promoters of a large number of genes involved in DNA metabolism and cell cycle regulation, concomitant with their transcriptional silencing. A comparison of ChIP-chip data with expression profiling data on resting E2f2−/− T lymphocytes identified a subset of 51 E2F2-specific target genes, most of which are upregulated on E2F2 loss. Luciferase reporter assays showed a retinoblastoma-independent role for E2F2 in the negative regulation of these target genes. Importantly, we show that the DNA binding activity of the transcription factor CREB contributes to E2F2-mediated repression of Mcm5 and Chk1 promoters. siRNA-mediated CREB knockdown, expression of a dominant negative KCREB mutant or disruption of CREB binding by mutating a CRE motif on Mcm5 promoter, relieved E2F2-mediated transcriptional repression. Taken together, our data uncover a new regulatory mechanism for E2F-mediated transcriptional control, whereby E2F2 and CREB cooperate in the transcriptional repression of a subset of E2F2 target genes.
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Affiliation(s)
- Usua Laresgoiti
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country, UPV/EHU, Bilbao 48940, Spain and Department of Biochemistry and Molecular Biology, University of the Basque Country, UPV/EHU, Bilbao 48940, Spain
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17
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Che Y, Best OG, Zhong L, Kaufman KL, Mactier S, Raftery M, Graves LM, Mulligan SP, Christopherson RI. Hsp90 Inhibitor SNX-7081 Dysregulates Proteins Involved with DNA Repair and Replication and the Cell Cycle in Human Chronic Lymphocytic Leukemia (CLL) Cells. J Proteome Res 2013; 12:1710-22. [DOI: 10.1021/pr301055y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yiping Che
- Cancer Proteomics Laboratory,
School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - O. Giles Best
- Northern Blood Research Centre,
Kolling Institute for Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Ling Zhong
- Bioanalytical Mass Spectrometry
Facility, University of New South Wales, Kensington, NSW 2052, Australia
| | - Kimberley L. Kaufman
- Cancer Proteomics Laboratory,
School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - Swetlana Mactier
- Cancer Proteomics Laboratory,
School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
| | - Mark Raftery
- Bioanalytical Mass Spectrometry
Facility, University of New South Wales, Kensington, NSW 2052, Australia
| | - Lee M. Graves
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina
27599-7365, United States
| | - Stephen P. Mulligan
- Northern Blood Research Centre,
Kolling Institute for Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Richard I. Christopherson
- Cancer Proteomics Laboratory,
School of Molecular Bioscience, University of Sydney, Sydney, NSW 2006, Australia
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18
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Takayanagi S, Fukuda R, Takeuchi Y, Tsukada S, Yoshida K. Gene regulatory network of unfolded protein response genes in endoplasmic reticulum stress. Cell Stress Chaperones 2013; 18:11-23. [PMID: 22802018 PMCID: PMC3508129 DOI: 10.1007/s12192-012-0351-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 06/29/2012] [Accepted: 07/02/2012] [Indexed: 02/08/2023] Open
Abstract
In the endoplasmic reticulum (ER), secretory and membrane proteins are properly folded and modified, and the failure of these processes leads to ER stress. At the same time, unfolded protein response (UPR) genes are activated to maintain homeostasis. Despite the thorough characterization of the individual gene regulation of UPR genes to date, further investigation of the mutual regulation among UPR genes is required to understand the complex mechanism underlying the ER stress response. In this study, we aimed to reveal a gene regulatory network formed by UPR genes, including immunoglobulin heavy chain-binding protein (BiP), X-box binding protein 1 (XBP1), C/EBP [CCAAT/enhancer-binding protein]-homologous protein (CHOP), PKR-like endoplasmic reticulum kinase (PERK), inositol-requiring 1 (IRE1), activating transcription factor 6 (ATF6), and ATF4. For this purpose, we focused on promoter-luciferase reporters for BiP, XBP1, and CHOP genes, which bear an ER stress response element (ERSE), and p5 × ATF6-GL3, which bears an unfolded protein response element (UPRE). We demonstrated that the luciferase activities of the BiP and CHOP promoters were upregulated by all the UPR genes, whereas those of the XBP1 promoter and p5 × ATF6-GL3 were upregulated by all the UPR genes except for BiP, CHOP, and ATF4 in HeLa cells. Therefore, an ERSE- and UPRE-centered gene regulatory network of UPR genes could be responsible for the robustness of the ER stress response. Finally, we revealed that BiP protein was degraded when cells were treated with DNA-damaging reagents, such as etoposide and doxorubicin; this finding suggests that the expression level of BiP is tightly regulated at the post-translational level, rather than at the transcriptional level, in the presence of DNA damage.
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Affiliation(s)
- Sayuri Takayanagi
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Riga Fukuda
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Yuuki Takeuchi
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Sakiko Tsukada
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
| | - Kenichi Yoshida
- Department of Life Sciences, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 Japan
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19
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Knoll S, Emmrich S, Pützer BM. The E2F1-miRNA Cancer Progression Network. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 774:135-47. [DOI: 10.1007/978-94-007-5590-1_8] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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20
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Zou L, Xu HG, Ren W, Jin R, Wang Y, Zhou GP. Transcriptional activation of the human CD2AP promoter by E2F1. PLoS One 2012; 7:e42774. [PMID: 22880102 PMCID: PMC3411847 DOI: 10.1371/journal.pone.0042774] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 07/11/2012] [Indexed: 12/24/2022] Open
Abstract
CD2-associated protein (CD2AP) is an adaptor molecule involved in T cell receptor signaling and podocyte homeostasis. CD2AP-deficient mice develop nephritic syndrome and renal failure caused by glomerulosclerosis. Transcription factor E2F1 is a key regulator of cell proliferation and apoptosis. Here we report that E2F1 up-regulates the human CD2AP promoter and further increases the mRNA and protein levels of the human CD2AP in human embryonic kidney (HEK) 293 cells. By semi-quantitative RT-PCR and Western blot analysis we demonstrate that ectopic expression of E2F1 elevates the mRNA and protein levels of CD2AP. Consistently, transient transfection assays prove that overexpression of E2F1 transactivates the CD2AP promoter while knocking-down of endogenous E2F1 by a shRNA strategy results in reduction of the CD2AP promoter activity. Toward understanding the underlying mechanism of this regulation, we performed chromatin immunoprecipitation and mutations of the putative Sp1 binding sites, demonstrating that E2F1 can bind to Sp1 binding site and overexpression of E2F1 is capable of increasing the binding of E2F1 and decreasing the binding of Sp1 to Sp1 binding sites.
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Affiliation(s)
- Li Zou
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Hua-Guo Xu
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
- Department of Clinical Laboratory, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Wei Ren
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Rui Jin
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yi Wang
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Guo-Ping Zhou
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
- * E-mail:
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21
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Rb/E2F1 regulates the innate immune receptor Toll-like receptor 3 in epithelial cells. Mol Cell Biol 2012; 32:1581-90. [PMID: 22310660 DOI: 10.1128/mcb.06454-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tumor suppressor genes regulate the antiviral host defense through molecular mechanisms that are not yet well explored. Here, we show that the tumor suppressor retinoblastoma (Rb) protein positively regulates Toll-like receptor 3 (TLR3) expression, the sensing receptor for viral double-stranded RNA and poly(I · C). TLR3 expression was lower in Rb knockout (Rb(-/-)) mouse embryonic fibroblasts (MEF) and in mammalian epithelial cells transfected with Rb small-interfering RNA (siRNA) than in control cells. Consequently, induction of cytokines interleukin-8 and beta interferon after poly(I · C) stimulation was impaired in Rb(-/-) MEF and Rb siRNA-transfected cells compared to controls. TLR3 promoter analysis showed that Rb modulates the transcription factor E2F1, which directly binds to the proximal promoter of TLR3. Exogenous addition of E2F1 decreased TLR3 promoter activity, while Rb dose dependently curbed the effect of E2F1. Interestingly, poly(I · C) increased the Rb expression, and the poly(I · C)-induced TLR3 expression was impaired in Rb-depleted cells, suggesting the importance of Rb in TLR3 induction by poly(I · C). Together, these data indicated that E2F1 suppresses TLR3 transcription, but during immune stimulation, Rb is upregulated to block the inhibitory effect of E2F1 on TLR3, highlighting a role of Rb-E2F1 axis in the innate immune response in epithelial cells.
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22
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Conserved RB functions in development and tumor suppression. Protein Cell 2011; 2:864-78. [PMID: 22180086 DOI: 10.1007/s13238-011-1117-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 10/18/2011] [Indexed: 12/21/2022] Open
Abstract
The variety of human cancers in which the retinoblastoma protein pRb is inactivated reflects both its broad importance for tumor suppression and its multitude of cellular functions. Accumulating evidence indicates that pRb contributes to a diversity of cellular functions, including cell proliferation, differentiation, cell death, and genome stability. pRb performs these diverse functions through the formation of large complexes that include E2F transcription factors and chromatin regulators. In this review we will discuss some of the recent advances made in understanding the structure and function of pRb as they relate to tumor suppression, and highlight research using Drosophila melanogaster that reveals important, evolutionarily conserved functions of the RB family.
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23
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Roy AL. Biochemistry and biology of the inducible multifunctional transcription factor TFII-I: 10 years later. Gene 2011; 492:32-41. [PMID: 22037610 DOI: 10.1016/j.gene.2011.10.030] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 10/08/2011] [Accepted: 10/11/2011] [Indexed: 12/12/2022]
Abstract
Exactly twenty years ago TFII-I was discovered as a biochemical entity that was able to bind to and function via a core promoter element called the Initiator (Inr). Since then several different properties of this signal-induced multifunctional factor were discovered. Here I update these ever expanding functions of TFII-I--focusing primarily on the last ten years since the first review appeared in this journal.
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Affiliation(s)
- Ananda L Roy
- Department of Pathology, Sackler School of Biomedical Sciences, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA.
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24
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Abstract
Retinoblastoma (Rb), a tumor suppressor gene, is inactivated in many types of cancer. However little is known about how the loss of Rb function can be targeted in cancer therapies. We have identified that inactivation of TSC2 in Rb mutant cancer cells will induce a synergistic cell death. The synergistic cell death is due to an increase in cellular stress including metabolic, ER, and oxidative stress. Therefore, inactivation of TSC2 and chemothereputics that result in induction of cellular stress may be a novel and effective way to treat cancers containing inactivated Rb.
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25
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Misra UK, Mowery YM, Gawdi G, Pizzo SV. Loss of cell surface TFII-I promotes apoptosis in prostate cancer cells stimulated with activated α₂ -macroglobulin. J Cell Biochem 2011; 112:1685-95. [PMID: 21503958 DOI: 10.1002/jcb.23083] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Receptor-recognized forms of α₂ -macroglobulin (α₂ M) bind to cell surface-associated GRP78 and initiate pro-proliferative and anti-apoptotic signaling. Ligation of GRP78 with α₂ M also upregulates TFII-I, which binds to the GRP78 promoter and enhances GRP78 synthesis. In addition to its transcriptional functions, cytosolic TFII-I regulates agonist-induced Ca(2+) entry. In this study we show that down regulation of TFII-I gene expression by RNAi profoundly impairs its cell surface expression and anti-apoptotic signaling as measured by significant reduction of GRP78, Bcl-2, and cyclin D1 in 1-Ln and DU-145 human prostate cancer cells stimulated with α₂ M. In contrast, this treatment significantly increases levels of the pro-apoptotic proteins p53, p27, Bax, and Bak and causes DNA fragmentation. Furthermore, down regulation of TFII-I expression activates agonist-induced Ca(2+) entry. In plasma membrane lysates p-PLCγ1, TRPC3, GRP78, MTJ1, and caveolin co-immunoprecipitate with TFII-I suggesting multimeric complexes of these proteins. Consistent with this hypothesis, down regulating TFII-I, MTJ1, or GRP78 expression by RNAi greatly attenuates cell surface expression of TFII-I. In conclusion, we demonstrate that not only does cell surface GRP78 regulate apoptosis, but it also regulates Ca(2+) homeostasis by controlling cell surface localization of TFII-I.
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Affiliation(s)
- U K Misra
- Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Gordon GM, Du W. Targeting Rb inactivation in cancers by synthetic lethality. Am J Cancer Res 2011; 1:773-786. [PMID: 21814623 PMCID: PMC3147291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 05/15/2011] [Indexed: 05/31/2023] Open
Abstract
The retinoblastoma protein, pRb, is a key regulator of cell proliferation, differentiation, apoptosis, as well as checkpoint and stress responses. The function of Rb is often inactivated in many types of cancers, a feature that can potentially be used to target this specific subset of cancers. However little is known about how the loss of Rb function can be exploited in cancer therapies. In this review, we overview the functions of Rb, and discuss a genetic screen that led to the finding that inactivation of TSC2 and Rb induces synergistic cell death in both Drosophila developing tissues and human cancer cells. The mechanisms for synergistic cell death involve the accumulation of cellular stress, suggesting that inactivation of TSC2 and chemotherapeutic agents that result in induction of cellular stress can potentially be combined to treat cancers harboring inactivated Rb.
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GRAMD4 mimics p53 and mediates the apoptotic function of p73 at mitochondria. Cell Death Differ 2010; 18:874-86. [PMID: 21127500 DOI: 10.1038/cdd.2010.153] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
p73, a member of the p53 family, shares high sequence homology with p53 and shows many p53-like properties: it binds to p53-DNA target sites, transactivates p53-responsive genes and induces cell cycle arrest and apoptosis. Apart from this transcription-dependent effect, less is known about the downstream mechanism(s) by which p73 controls cell fate at the mitochondria. We have previously identified GRAMD4 (alias KIAA0767 or Death-Inducing-Protein) as a novel p53-independent pro-apoptotic target of E2F1, which localizes to mitochondria. In this study, we found that p73-induced apoptosis is mediated by GRAMD4 expression and translocation to the mitochondria. We showed that this protein physically interacts with Bcl-2, promotes Bax mitochondrial relocalization and oligomerization, and is highly efficient in inducing mitochondrial membrane permeabilization with release of cytochrome c and Smac. Overexpression of p73α and p73β isoforms, but not p53, leads to direct GRAMD4 promoter transactivation. In addition, GRAMD4 induces changes in Bcl-2 and Bax protein levels. GRAMD4 transcription is activated in response to cisplatin (cDDP) in a manner dependent on endogenous p73. Using solid tumor xenografts, ectopic expression of GRAMD4 together with cDDP resulted in enhanced cancer killing. Our findings demonstrate that p73 is able to trigger apoptosis via the mitochondrial pathway by a new mechanism using pro-apoptotic GRAMD4 as mediator, and strongly support its p53-like function.
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Inberg A, Linial M. Protection of pancreatic beta-cells from various stress conditions is mediated by DJ-1. J Biol Chem 2010; 285:25686-98. [PMID: 20516060 DOI: 10.1074/jbc.m110.109751] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pancreatic beta-cells are vulnerable to multiple stresses, leading to dysfunction and apoptotic death. Deterioration in beta-cells function and mass is associated with type 2 diabetes. Comparative two-dimensional gel electrophoresis from pancreatic MIN6 cells that were maintained at varying glucose concentrations was carried out. An induced expression of a protein spot, detected in MIN6 cells experiencing high glucose concentration, was identified by mass spectrometry as the oxidized form of DJ-1. DJ-1 (park7) is a multifunctional protein implicated in familial Parkinsonism and neuroprotection in response to oxidative damage. The DJ-1 protein and its oxidized form were also induced following exposure to oxidative and endoplasmic reticulum stress in MIN6 and betaTC-6 cells and also in mouse pancreatic islets. Suppression of DJ-1 levels by small interfering RNA led to an accelerated cell death, whereas an increase in DJ-1 levels by adenovirus-based infection attenuated cell death induced by H(2)O(2) and thapsigargin in beta-cell lines and mouse pancreatic islets. Furthermore, DJ-1 improved regulated insulin secretion under basal as well as oxidative and endoplasmic reticulum stress conditions in a dose-dependent manner. We identified TFII-I (Gtf2i) as DJ-1 partner in the cytosol, whereas the binding of TFII-I to DJ-1 prevented TFII-I translocation to the nucleus. The outcome was attenuation of the stress response. Our results suggest that DJ-1 together with TFII-I operate in concert to cope with various insults and to sustain pancreatic beta-cell function.
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Affiliation(s)
- Alex Inberg
- Department of Biological Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Li B, Gordon GM, Charles HD, Xu J, Du W. Specific killing of Rb mutant cancer cells by inactivating TSC2. Cancer Cell 2010; 17:469-80. [PMID: 20478529 PMCID: PMC2873973 DOI: 10.1016/j.ccr.2010.03.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 12/30/2009] [Accepted: 04/02/2010] [Indexed: 12/18/2022]
Abstract
The retinoblastoma (Rb) tumor suppressor is often inactivated in cancers. To identify genes that can be used to specifically target such cancers, we carried out a genetic screen in Drosophila. We identified gig (fly TSC2) and found that inactivation of rbf (fly Rb) and gig synergistically induced cell death. Interestingly, inactivation of TSC2 specifically kills Rb mutant cancer cells under stress conditions, which is correlated with an inhibition of tumor growth. We show that cancer cell killing induced by concomitant inactivation of Rb and TSC2 is mediated by increased cellular stress, including oxidative stress. Inactivation of TSC2 and Rb synergistically induce oxidative stress via increased protein synthesis, inhibited de novo lipid synthesis, and decreased reactive oxygen species scavenger enzyme SOD2 induction.
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Affiliation(s)
- Binghui Li
- Ben May Department for Cancer Research, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
| | - Gabriel M. Gordon
- Ben May Department for Cancer Research, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
- Committee on Cancer Biology, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
| | - H. Du Charles
- Ben May Department for Cancer Research, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
| | - Jinhua Xu
- Ben May Department for Cancer Research, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
| | - Wei Du
- Ben May Department for Cancer Research, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
- Committee on Cancer Biology, University of Chicago, 929 E. 57 Street, Chicago, IL 60637, USA
- Corresponding author: , Phone: 773-834-1949, Fax 773-702-4476
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Engelmann D, Knoll S, Ewerth D, Steder M, Stoll A, Pützer BM. Functional interplay between E2F1 and chemotherapeutic drugs defines immediate E2F1 target genes crucial for cancer cell death. Cell Mol Life Sci 2010; 67:931-48. [PMID: 20013022 PMCID: PMC11115677 DOI: 10.1007/s00018-009-0222-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 11/04/2009] [Accepted: 11/20/2009] [Indexed: 10/20/2022]
Abstract
The E2F1 transcription factor enhances apoptosis by DNA damage in tumors lacking p53. To elucidate the mechanism of a potential cooperation between E2F1 and chemotherapy, whole-genome microarrays of chemoresistant tumor cell lines were performed focusing on the identification of cooperation response genes (CRG). This gene class is defined by a synergistic expression response upon endogenous E2F1 activation and drug treatment. Cluster analysis revealed an expression pattern of CRGs similar to E2F1 mono-therapy, suggesting that chemotherapeutics enhance E2F1-dependent gene expression at the transcriptional level. Using this approach as a tool to explore E2F1-driven gene expression in response to anticancer drugs, we identified novel apoptosis genes such as the tumor suppressor TIEG1/KLF10 as direct E2F1 targets. We show that TIEG1/KLF10 is transcriptionally activated by E2F1 and crucial for E2F1-mediated chemosensitization of cancer cells. Our results provide a broader picture of E2F1-regulated genes in conjunction with cytotoxic treatment that allows the design of more rational therapeutics.
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Affiliation(s)
- David Engelmann
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Susanne Knoll
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Daniel Ewerth
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Marc Steder
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Anja Stoll
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
| | - Brigitte M. Pützer
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
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Alla V, Engelmann D, Niemetz A, Pahnke J, Schmidt A, Kunz M, Emmrich S, Steder M, Koczan D, Pützer BM. E2F1 in melanoma progression and metastasis. J Natl Cancer Inst 2009; 102:127-33. [PMID: 20026813 DOI: 10.1093/jnci/djp458] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Metastases are responsible for cancer deaths, but the molecular alterations leading to tumor progression are unclear. Overexpression of the E2F1 transcription factor is common in high-grade tumors that are associated with poor patient survival. To investigate the association of enhanced E2F1 activity with aggressive phenotype, we performed a gene-specific silencing approach in a metastatic melanoma model. Knockdown of endogenous E2F1 via E2F1 small hairpin RNA (shRNA) expression increased E-cadherin expression of metastatic SK-Mel-147 melanoma cells and reduced their invasive potential but not their proliferative activity. Although growth rates of SK-Mel-147 and SK-Mel-103 xenograft tumors expressing E2F1 shRNA or control shRNA were similar, mice implanted with cells expressing E2F1 shRNA had a smaller area of metastases per lung than control mice (n = 3 mice per group; 5% vs 46%, difference = 41%, 95% confidence interval = 15% to 67%; P = .01; one-way analysis of variance). We identified epidermal growth factor receptor as a direct target of E2F1 and demonstrated that inhibition of receptor signaling abrogates E2F1-induced invasiveness, emphasizing the importance of the E2F1-epidermal growth factor receptor interaction as a driving force in melanoma progression that may serve as a paradigm for E2F1-induced metastasis in other human cancers.
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Affiliation(s)
- Vijay Alla
- Department of Vectorology and Experimental Gene Therapy, Biomedical Research Center, University of Rostock, Rostock, Germany
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Hiss DC, Gabriels GA. Implications of endoplasmic reticulum stress, the unfolded protein response and apoptosis for molecular cancer therapy. Part I: targeting p53, Mdm2, GADD153/CHOP, GRP78/BiP and heat shock proteins. Expert Opin Drug Discov 2009; 4:799-821. [PMID: 23496268 DOI: 10.1517/17460440903052559] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND In eukaryotes, endoplasmic reticulum stress (ERS) and the unfolded protein response (UPR) are coordinately regulated to maintain steady-state levels and activities of various cellular proteins to ensure cell survival. OBJECTIVE This review (Part I of II) focuses on specific ERS and UPR signalling regulators, their expression in the cancer phenotype and apoptosis, and proposes how their implication in these processes can be rationalised into proteasome inhibition, apoptosis induction and the development of more efficacious targeted molecular cancer therapies. METHOD In this review, we contextualise many ERS and UPR client proteins that are deregulated or mutated in cancers and show links between ERS and the UPR, their implication in oncogenic transformation, tumour progression and escape from immune surveillance, apoptosis inhibition, angiogenesis, metastasis, acquired drug resistance and poor cancer prognosis. CONCLUSION Evasion of programmed cell death or apoptosis is a hallmark of cancer that enables tumour cells to proliferate uncontrollably. Successful eradication of cancer cells through targeting ERS- and UPR-associated proteins to induce apoptosis is currently being pursued as a central tenet of anticancer drug discovery.
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Affiliation(s)
- Donavon C Hiss
- Head, Molecular Oncology Research Programme University of the Western Cape, Department of Medical BioSciences, Bellville, 7535, South Africa +27 21 959 2334 ; +27 21 959 1563 ;
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