1
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Lin KM, Weng LF, Chen SYJ, Lin SJ, Tsai CH. Upregulation of IQGAP2 by EBV transactivator Rta and its influence on EBV life cycle. J Virol 2023; 97:e0054023. [PMID: 37504571 PMCID: PMC10506479 DOI: 10.1128/jvi.00540-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 06/09/2023] [Indexed: 07/29/2023] Open
Abstract
Epstein-Barr virus (EBV) is a human oncogenic γ-herpesvirus that establishes persistent infection in more than 90% of the world's population. EBV has two life cycles, latency and lytic replication. Reactivation of EBV from latency to the lytic cycle is initiated and controlled by two viral immediate-early transcription factors, Zta and Rta, encoded by BZLF1 and BRLF1, respectively. In this study, we found that IQGAP2 expression was elevated in EBV-infected B cells and identified Rta as a viral gene responsible for the IQGAP2 upregulation in both B cells and nasopharyngeal carcinoma cell lines. Mechanistically, we showed that Rta increases IQGAP2 expression through direct binding to the Rta-responsive element in the IQGAP2 promoter. We also demonstrated the direct interaction between Rta and IQGAP2 as well as their colocalization in the nucleus. Functionally, we showed that the induced IQGAP2 is required for the Rta-mediated Rta promoter activation in the EBV lytic cycle progression and may influence lymphoblastoid cell line clumping morphology through regulating E-cadherin expression. IMPORTANCE Elevated levels of antibodies against EBV lytic proteins and increased EBV DNA copy numbers in the sera have been reported in patients suffering from Burkitt's lymphoma, Hodgkin's lymphoma, and nasopharyngeal carcinoma, indicating that EBV lytic cycle progression may play an important role in the pathogenesis of EBV-associated diseases and highlighting the need for a more complete mechanistic understanding of the EBV lytic cycle. Rta acts as an essential transcriptional activator to induce lytic gene expression and thus trigger EBV reactivation. In this study, scaffolding protein IQGAP2 was found to be upregulated prominently following EBV infection via the direct binding of Rta to the RRE in the IQGAP2 promoter but not in response to other biological stimuli. Importantly, IQGAP2 was demonstrated to interact with Rta and promote the EBV lytic cycle progression. Suppression of IQGAP2 was also found to decrease E-cadherin expression and affect the clumping morphology of lymphoblastoid cell lines.
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Affiliation(s)
- Kai-Min Lin
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Li-Fang Weng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan
| | - Shi-Yo Jill Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Sue-Jane Lin
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ching-Hwa Tsai
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
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2
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E2F1/CKS2/PTEN signaling axis regulates malignant phenotypes in pediatric retinoblastoma. Cell Death Dis 2022; 13:784. [PMID: 36096885 PMCID: PMC9468144 DOI: 10.1038/s41419-022-05222-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/15/2022] [Accepted: 08/31/2022] [Indexed: 01/21/2023]
Abstract
Retinoblastoma (RB) is the most common pediatric intraocular malignancy and is a serious vision- and life-threatening disease. The biallelic mutation of the retinoblastoma gene RB1 is the initial event in the malignant transformation of RB, but the exact molecular mechanism is still unclear. E2F transcription factors can be activated by RB1 loss of function and lead to uncontrolled cell division. Among E2F family numbers, E2F1 has higher expression abundance than E2F2 and E2F3 in RB clinical samples. By integrating E2F1 ChIP-seq data, RNA-seq profiling from RB samples and RNA-seq profiling upon E2F1 knockdown, together with pathway analysis, literature searching and experimental validation, we identified Cyclin-dependent kinases regulatory subunit 2 (CKS2) as a novel regulator in regulating tumor-associated phenotypes in RB. CKS2 exhibited aberrantly higher expression in RB. Depletion of CKS2 in Y79 retinoblastoma cell line led to reduced cell proliferation, delayed DNA replication and decreased clonogenic growth. Downregulation of CKS2 also slowed tumor xenograft growth in nude mice. Importantly, reversed expression of CKS2 rescued cancer-associated phenotypes. Mechanistically, transcription factor E2F1 enhanced CKS2 expression through binding to its promoter and CKS2 regulated the cancer-associated PI3K-AKT pathway. This study discovered E2F1/CKS2/PTEN signaling axis regulates malignant phenotypes in pediatric retinoblastoma, and CKS2 may serve as a potential therapeutic target for this disease.
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3
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The Breast Cancer Protooncogenes HER2, BRCA1 and BRCA2 and Their Regulation by the iNOS/NOS2 Axis. Antioxidants (Basel) 2022; 11:antiox11061195. [PMID: 35740092 PMCID: PMC9227079 DOI: 10.3390/antiox11061195] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 02/04/2023] Open
Abstract
The expression of inducible nitric oxide synthase (iNOS; NOS2) and derived NO in various cancers was reported to exert pro- and anti-tumorigenic effects depending on the levels of expression and the tumor types. In humans, the breast cancer level of iNOS was reported to be overexpressed, to exhibit pro-tumorigenic activities, and to be of prognostic significance. Likewise, the expression of the oncogenes HER2, BRCA1, and BRCA2 has been associated with malignancy. The interrelationship between the expression of these protooncogenes and oncogenes and the expression of iNOS is not clear. We have hypothesized that there exist cross-talk signaling pathways between the breast cancer protooncogenes, the iNOS axis, and iNOS-mediated NO mutations of these protooncogenes into oncogenes. We review the molecular regulation of the expression of the protooncogenes in breast cancer and their interrelationships with iNOS expression and activities. In addition, we discuss the roles of iNOS, HER2, BRCA1/2, and NO metabolism in the pathophysiology of cancer stem cells. Bioinformatic analyses have been performed and have found suggested molecular alterations responsible for breast cancer aggressiveness. These include the association of BRCA1/2 mutations and HER2 amplifications with the dysregulation of the NOS pathway. We propose that future studies should be undertaken to investigate the regulatory mechanisms underlying the expression of iNOS and various breast cancer oncogenes, with the aim of identifying new therapeutic targets for the treatment of breast cancers that are refractory to current treatments.
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4
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Rajasekaran S, Siddiqui J, Rakijas J, Nicolay B, Lin C, Khan E, Patel R, Morris R, Wyler E, Boukhali M, Balasubramanyam J, Ranjith Kumar R, Van Rechem C, Vogel C, Elchuri SV, Landthaler M, Obermayer B, Haas W, Dyson N, Miles W. Integrated multi-omics analysis of RB-loss identifies widespread cellular programming and synthetic weaknesses. Commun Biol 2021; 4:977. [PMID: 34404904 PMCID: PMC8371045 DOI: 10.1038/s42003-021-02495-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 07/26/2021] [Indexed: 11/09/2022] Open
Abstract
Inactivation of RB is one of the hallmarks of cancer, however gaps remain in our understanding of how RB-loss changes human cells. Here we show that pRB-depletion results in cellular reprogramming, we quantitatively measured how RB-depletion altered the transcriptional, proteomic and metabolic output of non-tumorigenic RPE1 human cells. These profiles identified widespread changes in metabolic and cell stress response factors previously linked to E2F function. In addition, we find a number of additional pathways that are sensitive to RB-depletion that are not E2F-regulated that may represent compensatory mechanisms to support the growth of RB-depleted cells. To determine whether these molecular changes are also present in RB1-/- tumors, we compared these results to Retinoblastoma and Small Cell Lung Cancer data, and identified widespread conservation of alterations found in RPE1 cells. To define which of these changes contribute to the growth of cells with de-regulated E2F activity, we assayed how inhibiting or depleting these proteins affected the growth of RB1-/- cells and of Drosophila E2f1-RNAi models in vivo. From this analysis, we identify key metabolic pathways that are essential for the growth of pRB-deleted human cells.
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Affiliation(s)
- Swetha Rajasekaran
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Jalal Siddiqui
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Jessica Rakijas
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Brandon Nicolay
- Massachusetts General Hospital Cancer Center, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA.,Agios Pharmaceutical, Cambridge, MA, USA
| | - Chenyu Lin
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Eshan Khan
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Rahi Patel
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Robert Morris
- Massachusetts General Hospital Cancer Center, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Emanuel Wyler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Myriam Boukhali
- Massachusetts General Hospital Cancer Center, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Jayashree Balasubramanyam
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - R Ranjith Kumar
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | | | - Christine Vogel
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, USA
| | - Sailaja V Elchuri
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Markus Landthaler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Benedikt Obermayer
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,IRI Life Sciences, Institute für Biologie, Humboldt Universität zu Berlin, Berlin, Germany.,Core Unit Bioinformatics, Berlin Institute of Health (BIH), Berlin, Germany
| | - Wilhelm Haas
- Massachusetts General Hospital Cancer Center, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Nicholas Dyson
- Massachusetts General Hospital Cancer Center, Charlestown, MA, USA. .,Harvard Medical School, Boston, MA, USA.
| | - Wayne Miles
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH, USA. .,The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA.
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5
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Abstract
The use of DNA-damaging agents such as radiotherapy and chemotherapy has been a mainstay treatment protocol for many cancers, including lung and prostate. Recently, FDA approval of inhibitors of DNA repair, and targeting innate immunity to enhance the efficacy of DNA-damaging agents have gained much attention. Yet, inherent or acquired resistance against DNA-damaging therapies persists as a fundamental drawback. While cancer eradication by causing cancer cell death through induction of apoptosis is the ultimate goal of anti-cancer treatments, autophagy and senescence are two major cellular responses induced by clinically tolerable doses of DNA-damaging therapies. Unlike apoptosis, autophagy and senescence can act as both pro-tumorigenic as well as tumor suppressive mechanisms. DNA damage-induced senescence is associated with a pro-inflammatory secretory phenotype, which contributes to reshaping the tumor- immune microenvironment. Moreover, PTEN (phosphatase and tensin homolog) is a tumor supressor deleted in many tumors, and has been implicated in both senescence and autophagy. This review presents an overview of the literature on the regulation and consequences of DNA damage- induced senescence in cancer cells, with a specific focus on autophagy and PTEN. Both autophagy and senescence occur concurrently in the same cells in response to DNA damaging agents. However, a deterministic relationship between these fundamental processes has been controversial. We present experimental evidence obtained with tumor cells, with a prime focus on two models of cancer, prostate and lung. A better understanding of mechanisms associated with DNA damage-induced cellular senescence is central to fully exploit the potential of DNA-damaging agents against cancer.
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Affiliation(s)
- Arishya Sharma
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States.
| | - Alexandru Almasan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, United States; Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH, United States.
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6
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Pan JH, Kim H, Tang J, Beane KE, Park JW, Kong S, Kong BC, Kim YJ, Shin EC, Kim JH, Zhao J, Lee JH, Kim JK. Acute alcohol consumption-induced let-7a inhibition exacerbates hepatic apoptosis by regulating Rb1 in mice. Alcohol 2020; 85:13-20. [PMID: 31734308 DOI: 10.1016/j.alcohol.2019.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/16/2019] [Accepted: 10/31/2019] [Indexed: 10/25/2022]
Abstract
Alcohol consumption is a critical risk factor for hepatic pathogenesis, including alcoholic liver diseases (ALD), but implications of alcohol-induced dysregulation of microRNA (miRNA) in ALD pathogenesis are not completely understood. In the present study, C57BL/6J male mice were treated with saline (CON; oral gavage; n = 8) or alcohol (EtOH; 3 g/kg body weight; oral gavage; n = 8) for 7 days. A total of 599 miRNAs and 158 key mRNAs related to fatty liver and hepatotoxicity pathways were assessed in mice liver tissues. The mRNA expression datasets were then utilized to predict interactions with miRNAs that were changed by alcohol consumption. Predicted miRNA-mRNA interactions were validated using in vitro miRNA transfection experiments. The results showed that let-7a was significantly decreased in the EtOH group and Rb1 mRNA was predicted as a target gene. This was further supported by an inverse correlation of RB1 and let-7a expression in mice liver tissue. Additionally, key protein expressions involved in RB1-apoptosis axis [i.e., p73, cleaved CASP-3 (cCASP-3), and cCASP-7] showed a trend of increase in the EtOH mice; this was also confirmed by capase-3 enzyme activity and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay in livers of mice that had consumed alcohol. In line with our in vivo observations, alcohol treatment suppressed the let-7a expression and subsequently upregulated p73, cCASP-3, and cCASP-7 protein expressions in mice hepatocytes. Additional proteins in the apoptosis regulatory pathway (i.e., MDM2-p53 axis) were significantly changed in response to let-7a suppression in the cells. Taken together, the current study provides mechanistic evidence that alcohol consumption-induced let-7a suppression results in the upregulation of RB1, thereby promoting hepatic apoptosis through induction of pro-apoptotic proteins (e.g., p73), and by, at least in part, preventing MDM2-mediated p53 degradation.
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Abstract
The transition between proliferating and quiescent states must be carefully regulated to ensure that cells divide to create the cells an organism needs only at the appropriate time and place. Cyclin-dependent kinases (CDKs) are critical for both transitioning cells from one cell cycle state to the next, and for regulating whether cells are proliferating or quiescent. CDKs are regulated by association with cognate cyclins, activating and inhibitory phosphorylation events, and proteins that bind to them and inhibit their activity. The substrates of these kinases, including the retinoblastoma protein, enforce the changes in cell cycle status. Single cell analysis has clarified that competition among factors that activate and inhibit CDK activity leads to the cell's decision to enter the cell cycle, a decision the cell makes before S phase. Signaling pathways that control the activity of CDKs regulate the transition between quiescence and proliferation in stem cells, including stem cells that generate muscle and neurons. © 2020 American Physiological Society. Compr Physiol 10:317-344, 2020.
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Affiliation(s)
- Hilary A Coller
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California, USA.,Department of Biological Chemistry, David Geffen School of Medicine, and the Molecular Biology Institute, University of California, Los Angeles, California, USA.,Molecular Biology Institute, University of California, Los Angeles, California, USA
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8
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Caspases interplay with kinases and phosphatases to determine cell fate. Eur J Pharmacol 2019; 855:20-29. [DOI: 10.1016/j.ejphar.2019.04.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 04/05/2019] [Accepted: 04/29/2019] [Indexed: 12/15/2022]
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9
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Indovina P, Pentimalli F, Conti D, Giordano A. Translating RB1 predictive value in clinical cancer therapy: Are we there yet? Biochem Pharmacol 2019; 166:323-334. [PMID: 31176618 DOI: 10.1016/j.bcp.2019.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/03/2019] [Indexed: 12/16/2022]
Abstract
The retinoblastoma RB1 gene has been identified in the 80s as the first tumor suppressor. RB1 loss of function, as well alterations in its pathway, occur in most human cancers and often have prognostic value. RB1 has a key role in restraining cell cycle entry and, along with its family members, regulates a myriad of cellular processes and affects cell response to a variety of stimuli, ultimately determining cell fate. Consistently, RB1 status is a crucial determinant of the cell response to antitumoral therapies, impacting on the outcome of both traditional and modern anti-cancer strategies, including precision medicine approaches, such as kinase inhibitors, and immunotherapy. Despite many efforts however, the predictive value of RB1 status in the clinical practice is still underused, mainly owing to the complexity of RB1 function, to differences depending on the cellular context and on the therapeutic strategies, and, not-lastly, to technical issues. Here, we provide an overview of studies analyzing the role of RB1 in response to conventional cytotoxic and cytostatic therapeutic agents in different cancer types, including hormone dependent ones. We also review RB1 predictive value in the response to the last generation CDK4/6 inhibitors, other kinase inhibitors, and immunotherapy and discuss new emerging non-canonical roles of RB1 that could impact on the response to antitumoral treatments.
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Affiliation(s)
- Paola Indovina
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
| | - Francesca Pentimalli
- Cell Biology and Biotherapy Unit, Istituto Nazionale Tumori, IRCCS, Fondazione G. Pascale, Napoli 80131, Italy
| | - Daniele Conti
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA; Department of Medical Biotechnologies, University of Siena, Siena 53100, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA; Department of Medical Biotechnologies, University of Siena, Siena 53100, Italy.
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10
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Rajasekaran S, Nagarajha Selvan LD, Dotts K, Kumar R, Rishi P, Khetan V, Bisht M, Sivaraman K, Krishnakumar S, Sahoo D, Campbell MJ, Elchuri SV, Miles WO. Non-coding and Coding Transcriptional Profiles Are Significantly Altered in Pediatric Retinoblastoma Tumors. Front Oncol 2019; 9:221. [PMID: 31058073 PMCID: PMC6477087 DOI: 10.3389/fonc.2019.00221] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/12/2019] [Indexed: 12/11/2022] Open
Abstract
Retinoblastoma is a rare pediatric tumor of the retina, caused by the homozygous loss of the Retinoblastoma 1 (RB1) tumor suppressor gene. Previous microarray studies have identified changes in the expression profiles of coding genes; however, our understanding of how non-coding genes change in this tumor is absent. This is an important area of research, as in many adult malignancies, non-coding genes including LNC-RNAs are used as biomarkers to predict outcome and/or relapse. To establish a complete and in-depth RNA profile, of both coding and non-coding genes, in Retinoblastoma tumors, we conducted RNA-seq from a cohort of tumors and normal retina controls. This analysis identified widespread transcriptional changes in the levels of both coding and non-coding genes. Unexpectedly, we also found rare RNA fusion products resulting from genomic alterations, specific to Retinoblastoma tumor samples. We then determined whether these gene expression changes, of both coding and non-coding genes, were also found in a completely independent Retinoblastoma cohort. Using our dataset, we then profiled the potential effects of deregulated LNC-RNAs on the expression of neighboring genes, the entire genome, and on mRNAs that contain a putative area of homology. This analysis showed that most deregulated LNC-RNAs do not act locally to change the transcriptional environment, but potentially function to modulate genes at distant sites. From this analysis, we selected a strongly down-regulated LNC-RNA in Retinoblastoma, DRAIC, and found that restoring DRAIC RNA levels significantly slowed the growth of the Y79 Retinoblastoma cell line. Collectively, our work has generated the first non-coding RNA profile of Retinoblastoma tumors and has found that these tumors show widespread transcriptional deregulation.
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Affiliation(s)
- Swetha Rajasekaran
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States.,The Ohio State University Comprehensive Cancer Center, Columbus, OH,, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | | | - Kathleen Dotts
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States.,The Ohio State University Comprehensive Cancer Center, Columbus, OH,, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Ranjith Kumar
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | - Pukhraj Rishi
- Shri Bhagwan Mahavir Vitreoretinal Services and Ocular Oncology Services, Medical Research Foundation, Sankara Nethralaya, Chennai, India
| | - Vikas Khetan
- Shri Bhagwan Mahavir Vitreoretinal Services and Ocular Oncology Services, Medical Research Foundation, Sankara Nethralaya, Chennai, India
| | - Madhoolika Bisht
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States.,The Ohio State University Comprehensive Cancer Center, Columbus, OH,, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | | | | | - Debashis Sahoo
- Department of Pediatrics and Department of Computer Science and Engineering, University of California, San Diego, San Diego, CA, United States
| | - Moray J Campbell
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH, United States
| | - Sailaja V Elchuri
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | - Wayne O Miles
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, United States.,The Ohio State University Comprehensive Cancer Center, Columbus, OH,, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States
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11
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Manuguerra S, Espinosa Ruiz C, Santulli A, Messina CM. Sub-lethal Doses of Polybrominated Diphenyl Ethers, in Vitro, Promote Oxidative Stress and Modulate Molecular Markers Related to Cell Cycle, Antioxidant Balance and Cellular Energy Management. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16040588. [PMID: 30781636 PMCID: PMC6406823 DOI: 10.3390/ijerph16040588] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 01/08/2023]
Abstract
In the present study, we evaluated the effects of different concentrations of the polybrominated diphenyl ethers (PBDEs) BDE-209, BDE-47 and BDE-99, on the vitality and oxidative stress of a HS-68 human cell culture exposed to the compounds for three days. The results showed that for this exposure time, only the highest concentrations produced a significant vitality reduction and oxidative stress induction (p < 0.05), measured as reactive oxygen species (ROS). Subsequently, in order to verify the effects of sub-lethal doses, cells were exposed for a longer time and data collected, after 12 and 20 days, to study ROS production and some molecular markers related to cell cycle and stress (p53, pRB, PARP, c-Jun and c-Fos), antioxidant status and proliferation (ERK, c-Jun and c-Fos), energy balance (NRF2, AMPK, HIF). Most of the biomarkers were influenced by the treatments, indicating that sub-lethal doses of PBDEs, for longer time, can enhance the production of ROS, altering the energetic metabolism, cell cycle and antioxidant balance, determining possible negative effects on the cell proliferation equilibrium.
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Affiliation(s)
- Simona Manuguerra
- Department of Earth and Sea Science, Laboratory of Marine Biochemistry and Ecotoxicology, University of Palermo, Via Barlotta 4, 91100 Trapani, Italy.
| | - Cristóbal Espinosa Ruiz
- Department of Earth and Sea Science, Laboratory of Marine Biochemistry and Ecotoxicology, University of Palermo, Via Barlotta 4, 91100 Trapani, Italy.
| | - Andrea Santulli
- Department of Earth and Sea Science, Laboratory of Marine Biochemistry and Ecotoxicology, University of Palermo, Via Barlotta 4, 91100 Trapani, Italy.
- Marine Biology Institute, Consorzio Universitario della Provincia di Trapani, Via Barlotta 4, 91100 Trapani, Italy.
| | - Concetta Maria Messina
- Department of Earth and Sea Science, Laboratory of Marine Biochemistry and Ecotoxicology, University of Palermo, Via Barlotta 4, 91100 Trapani, Italy.
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12
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Nalli Y, Arora P, Khan S, Malik F, Riyaz-Ul-Hassan S, Gupta V, Ali A. Isolation, structural modification of macrophin from endophytic fungus Phoma macrostoma and their cytotoxic potential. Med Chem Res 2019. [DOI: 10.1007/s00044-018-2281-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Furuta T, Joo HJ, Trimmer KA, Chen SY, Arur S. GSK-3 promotes S-phase entry and progression in C. elegans germline stem cells to maintain tissue output. Development 2018; 145:dev.161042. [PMID: 29695611 DOI: 10.1242/dev.161042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 04/17/2018] [Indexed: 12/26/2022]
Abstract
Adult C. elegans germline stem cells (GSCs) and mouse embryonic stem cells (mESCs) exhibit a non-canonical cell cycle structure with an abbreviated G1 phase and phase-independent expression of Cdk2 and cyclin E. Mechanisms that promote the abbreviated cell cycle remain unknown, as do the consequences of not maintaining an abbreviated cell cycle in these tissues. In GSCs, we discovered that loss of gsk-3 results in reduced GSC proliferation without changes in differentiation or responsiveness to GLP-1/Notch signaling. We find that DPL-1 transcriptional activity inhibits CDK-2 mRNA accumulation in GSCs, which leads to slower S-phase entry and progression. Inhibition of dpl-1 or transgenic expression of CDK-2 via a heterologous germline promoter rescues the S-phase entry and progression defects of the gsk-3 mutants, demonstrating that transcriptional regulation rather than post-translational control of CDK-2 establishes the abbreviated cell cycle structure in GSCs. This highlights an inhibitory cascade wherein GSK-3 inhibits DPL-1 and DPL-1 inhibits cdk-2 transcription. Constitutive GSK-3 activity through this cascade maintains an abbreviated cell cycle structure to permit the efficient proliferation of GSCs necessary for continuous tissue output.
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Affiliation(s)
- Tokiko Furuta
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Hyoe-Jin Joo
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kenneth A Trimmer
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.,Genes and Development Graduate Program, MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Shin-Yu Chen
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Swathi Arur
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA .,Genes and Development Graduate Program, MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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14
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Proteomic features of delayed ocular symptoms caused by exposure to sulfur mustard: As studied by protein profiling of corneal epithelium. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1445-1454. [DOI: 10.1016/j.bbapap.2017.08.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 08/11/2017] [Accepted: 08/31/2017] [Indexed: 12/21/2022]
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15
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Clavier A, Rincheval-Arnold A, Baillet A, Mignotte B, Guénal I. Two different specific JNK activators are required to trigger apoptosis or compensatory proliferation in response to Rbf1 in Drosophila. Cell Cycle 2016; 15:283-94. [PMID: 26825229 DOI: 10.1080/15384101.2015.1100776] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The Jun Kinase (JNK) signaling pathway responds to diverse stimuli by appropriate and specific cellular responses such as apoptosis, differentiation or proliferation. The mechanisms that mediate this specificity remain largely unknown. The core of this signaling pathway, composed of a JNK protein and a JNK kinase (JNKK), can be activated by various putative JNKK kinases (JNKKK) which are themselves downstream of different adaptor proteins. A proposed hypothesis is that the JNK pathway specific response lies in the combination of a JNKKK and an adaptor protein upstream of the JNKK. We previously showed that the Drosophila homolog of pRb (Rbf1) and a mutant form of Rbf1 (Rbf1(D253A)) have JNK-dependent pro-apoptotic properties. Rbf1(D253A) is also able to induce a JNK-dependent abnormal proliferation. Here, we show that Rbf1-induced apoptosis triggers proliferation which depends on the JNK pathway activation. Taking advantage of these phenotypes, we investigated the JNK signaling involved in either Rbf1-induced apoptosis or in proliferation in response to Rbf1-induced apoptosis. We demonstrated that 2 different JNK pathways involving different adaptor proteins and kinases are involved in Rbf1-apoptosis (i.e. Rac1-dTak1-dMekk1-JNK pathway) and in proliferation in response to Rbf1-induced apoptosis (i.e., dTRAF1-Slipper-JNK pathway). Using a transient induction of rbf1, we show that Rbf1-induced apoptosis activates a compensatory proliferation mechanism which also depends on Slipper and dTRAF1. Thus, these 2 proteins seem to be key players of compensatory proliferation in Drosophila.
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Affiliation(s)
- Amandine Clavier
- a Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire , EA4589 , Montigny-le-Bretonneux ; France.,b Ecole Pratique des Hautes Etudes, Laboratoire de Génétique Moléculaire et Physiologique , Montigny-le-Bretonneux , France
| | - Aurore Rincheval-Arnold
- a Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire , EA4589 , Montigny-le-Bretonneux ; France
| | - Adrienne Baillet
- a Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire , EA4589 , Montigny-le-Bretonneux ; France.,b Ecole Pratique des Hautes Etudes, Laboratoire de Génétique Moléculaire et Physiologique , Montigny-le-Bretonneux , France
| | - Bernard Mignotte
- a Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire , EA4589 , Montigny-le-Bretonneux ; France.,b Ecole Pratique des Hautes Etudes, Laboratoire de Génétique Moléculaire et Physiologique , Montigny-le-Bretonneux , France
| | - Isabelle Guénal
- a Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire de Génétique et Biologie Cellulaire , EA4589 , Montigny-le-Bretonneux ; France
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16
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Indovina P, Pentimalli F, Casini N, Vocca I, Giordano A. RB1 dual role in proliferation and apoptosis: cell fate control and implications for cancer therapy. Oncotarget 2016; 6:17873-90. [PMID: 26160835 PMCID: PMC4627222 DOI: 10.18632/oncotarget.4286] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 06/06/2015] [Indexed: 01/14/2023] Open
Abstract
Inactivation of the retinoblastoma (RB1) tumor suppressor is one of the most frequent and early recognized molecular hallmarks of cancer. RB1, although mainly studied for its role in the regulation of cell cycle, emerged as a key regulator of many biological processes. Among these, RB1 has been implicated in the regulation of apoptosis, the alteration of which underlies both cancer development and resistance to therapy. RB1 role in apoptosis, however, is still controversial because, depending on the context, the apoptotic cues, and its own status, RB1 can act either by inhibiting or promoting apoptosis. Moreover, the mechanisms whereby RB1 controls both proliferation and apoptosis in a coordinated manner are only now beginning to be unraveled. Here, by reviewing the main studies assessing the effect of RB1 status and modulation on these processes, we provide an overview of the possible underlying molecular mechanisms whereby RB1, and its family members, dictate cell fate in various contexts. We also describe the current antitumoral strategies aimed at the use of RB1 as predictive, prognostic and therapeutic target in cancer. A thorough understanding of RB1 function in controlling cell fate determination is crucial for a successful translation of RB1 status assessment in the clinical setting.
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Affiliation(s)
- Paola Indovina
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.,Department of Medicine, Surgery and Neuroscience, University of Siena and Istituto Toscano Tumori (ITT), Siena, Italy
| | - Francesca Pentimalli
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori "Fodazione G. Pascale" - IRCCS, Naples, Italy
| | - Nadia Casini
- Department of Medicine, Surgery and Neuroscience, University of Siena and Istituto Toscano Tumori (ITT), Siena, Italy
| | - Immacolata Vocca
- Oncology Research Center of Mercogliano (CROM), Istituto Nazionale Tumori "Fodazione G. Pascale" - IRCCS, Naples, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.,Department of Medicine, Surgery and Neuroscience, University of Siena and Istituto Toscano Tumori (ITT), Siena, Italy
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17
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Ma W, Yu J, Qi X, Liang L, Zhang Y, Ding Y, Lin X, Li G, Ding Y. Radiation-induced microRNA-622 causes radioresistance in colorectal cancer cells by down-regulating Rb. Oncotarget 2016; 6:15984-94. [PMID: 25961730 PMCID: PMC4599251 DOI: 10.18632/oncotarget.3762] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/06/2015] [Indexed: 02/06/2023] Open
Abstract
The standard treatment for patients with locally advanced rectal cancer is preoperative 5-fluorouracil-based chemoradiotherapy followed by total mesorectal excision. However, tumor response to standard dose radiation varies. In this study, we found that miR-622 was increased significantly in ionizing radiation-treated colorectal cancer (CRC) cells compared to the cells cultured with irradiated medium, and persisted stably in surviving cells treated with continuous low-dose radiation. Overexpression of miR-622 induced the radioresistance in vitro. In addition, miR-622 inhibited Rb expression by directly targeting RB1-3′UTR. Overexpression of Rb reversed miR-622-induced radioresistance in vitro. In response to ionizing radiation, the Rb-E2F1-P/CAF complex activated proapoptotic genes. Importantly, miR-622 was highly expressed in tumors of rectal cancer patients with non-regression after standard dose radiotherapy. In conclusion, miR-622 overexpressing cells are induced or selected by radiotherapy, causing in turn radioresistance and poor response to further therapy. MiR-622 is a potential biomarker of responders for radiotherapy and a potential therapeutic target.
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Affiliation(s)
- Wenhui Ma
- Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiang Yu
- Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaolong Qi
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Department of Gastroenterology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Li Liang
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yan Zhang
- Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yi Ding
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoshan Lin
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Guoxin Li
- Department of General Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yanqing Ding
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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18
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Abstract
There is an extensive and growing body of evidence that DNA replication stress is a major driver in the development and progression of many cancers, and that these cancers rely heavily on replication stress response pathways for their continued proliferation. This raises the possibility that the pathways that ordinarily protect cells from the accumulation of cancer-causing mutations may actually prove to be effective therapeutic targets for a wide range of malignancies. In this review, we explore the mechanisms by which sustained proliferation can lead to replication stress and genome instability, and discuss how the pattern of mutations observed in human cancers is supportive of this oncogene-induced replication stress model. Finally, we go on to consider the implications of replication stress both as a prognostic indicator and, more encouragingly, as a potential target in cancer treatment.
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Affiliation(s)
- Elaine M Taylor
- Lancaster Medical School, Faculty of Health & Medicine, Lancaster University, Lancaster, LA1 4YG, UK
| | - Howard D Lindsay
- Lancaster Medical School, Faculty of Health & Medicine, Lancaster University, Lancaster, LA1 4YG, UK
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19
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Human mutations in methylenetetrahydrofolate dehydrogenase 1 impair nuclear de novo thymidylate biosynthesis. Proc Natl Acad Sci U S A 2014; 112:400-5. [PMID: 25548164 DOI: 10.1073/pnas.1414555112] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An inborn error of metabolism associated with mutations in the human methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) gene has been identified. The proband presented with SCID, megaloblastic anemia, and neurologic abnormalities, but the causal metabolic impairment is unknown. SCID has been associated with impaired purine nucleotide metabolism, whereas megaloblastic anemia has been associated with impaired de novo thymidylate (dTMP) biosynthesis. MTHFD1 functions to condense formate with tetrahydrofolate and serves as the primary entry point of single carbons into folate-dependent one-carbon metabolism in the cytosol. In this study, we examined the impact of MTHFD1 loss of function on folate-dependent purine, dTMP, and methionine biosynthesis in fibroblasts from the proband with MTHFD1 deficiency. The flux of formate incorporation into methionine and dTMP was decreased by 90% and 50%, respectively, whereas formate flux through de novo purine biosynthesis was unaffected. Patient fibroblasts exhibited enriched MTHFD1 in the nucleus, elevated uracil in DNA, lower rates of de novo dTMP synthesis, and increased salvage pathway dTMP biosynthesis relative to control fibroblasts. These results provide evidence that impaired nuclear de novo dTMP biosynthesis can lead to both megaloblastic anemia and SCID in MTHFD1 deficiency.
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20
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Elkholi R, Renault TT, Serasinghe MN, Chipuk JE. Putting the pieces together: How is the mitochondrial pathway of apoptosis regulated in cancer and chemotherapy? Cancer Metab 2014; 2:16. [PMID: 25621172 PMCID: PMC4304082 DOI: 10.1186/2049-3002-2-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/20/2014] [Indexed: 02/08/2023] Open
Abstract
In order to solve a jigsaw puzzle, one must first have the complete picture to logically connect the pieces. However, in cancer biology, we are still gaining an understanding of all the signaling pathways that promote tumorigenesis and how these pathways can be pharmacologically manipulated by conventional and targeted therapies. Despite not having complete knowledge of the mechanisms that cause cancer, the signaling networks responsible for cancer are becoming clearer, and this information is serving as a solid foundation for the development of rationally designed therapies. One goal of chemotherapy is to induce cancer cell death through the mitochondrial pathway of apoptosis. Within this review, we present the pathways that govern the cellular decision to undergo apoptosis as three distinct, yet connected puzzle pieces: (1) How do oncogene and tumor suppressor pathways regulate apoptosis upstream of mitochondria? (2) How does the B-cell lymphoma 2 (BCL-2) family influence tumorigenesis and chemotherapeutic responses? (3) How is post-mitochondrial outer membrane permeabilization (MOMP) regulation of cell death relevant in cancer? When these pieces are united, it is possible to appreciate how cancer signaling directly impacts upon the fundamental cellular mechanisms of apoptosis and potentially reveals novel pharmacological targets within these pathways that may enhance chemotherapeutic success.
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Affiliation(s)
- Rana Elkholi
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, 1425 Madison Avenue, Box 1130, New York, NY 10029, USA.,Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA
| | - Thibaud T Renault
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, 1425 Madison Avenue, Box 1130, New York, NY 10029, USA.,Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA
| | - Madhavika N Serasinghe
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, 1425 Madison Avenue, Box 1130, New York, NY 10029, USA.,Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA
| | - Jerry E Chipuk
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, 1425 Madison Avenue, Box 1130, New York, NY 10029, USA.,Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.,The Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA
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21
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The pro-apoptotic activity of Drosophila Rbf1 involves dE2F2-dependent downregulation of diap1 and buffy mRNA. Cell Death Dis 2014; 5:e1405. [PMID: 25188515 PMCID: PMC4540203 DOI: 10.1038/cddis.2014.372] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 07/23/2014] [Accepted: 07/28/2014] [Indexed: 11/16/2022]
Abstract
The retinoblastoma gene, rb, ensures at least its tumor suppressor function by inhibiting cell proliferation. Its role in apoptosis is more complex and less described than its role in cell cycle regulation. Rbf1, the Drosophila homolog of Rb, has been found to be pro-apoptotic in proliferative tissue. However, the way it induces apoptosis at the molecular level is still unknown. To decipher this mechanism, we induced rbf1 expression in wing proliferative tissue. We found that Rbf1-induced apoptosis depends on dE2F2/dDP heterodimer, whereas dE2F1 transcriptional activity is not required. Furthermore, we highlight that Rbf1 and dE2F2 downregulate two major anti-apoptotic genes in Drosophila: buffy, an anti-apoptotic member of Bcl-2 family and diap1, a gene encoding a caspase inhibitor. On the one hand, Rbf1/dE2F2 repress buffy at the transcriptional level, which contributes to cell death. On the other hand, Rbf1 and dE2F2 upregulate how expression. How is a RNA binding protein involved in diap1 mRNA degradation. By this way, Rbf1 downregulates diap1 at a post-transcriptional level. Moreover, we show that the dREAM complex has a part in these transcriptional regulations. Taken together, these data show that Rbf1, in cooperation with dE2F2 and some members of the dREAM complex, can downregulate the anti-apoptotic genes buffy and diap1, and thus promote cell death in a proliferative tissue.
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22
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Mapping genetic alterations causing chemoresistance in cancer: identifying the roads by tracking the drivers. Oncogene 2013; 32:5315-30. [PMID: 23474753 DOI: 10.1038/onc.2013.48] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/16/2013] [Accepted: 01/16/2013] [Indexed: 12/12/2022]
Abstract
Although new agents are implemented to cancer therapy, we lack fundamental understandings of the mechanisms of chemoresistance, the main obstacle to cure in cancer. Here we review clinical evidence linking molecular defects to drug resistance across different tumour forms and discuss contemporary experimental evidence exploring these mechanisms. Although evidence, in general, is sparse and fragmentary, merging knowledge links drug resistance, and also sensitivity, to defects in functional pathways having a key role in cell growth arrest or death and DNA repair. As these pathways may act in concert, there is a need to explore multiple mechanisms in parallel. Taking advantage of massive parallel sequencing and other novel high-throughput technologies and base research on biological hypotheses, we now have the possibility to characterize functional defects related to these key pathways and to design a new generation of studies identifying the mechanisms controlling resistance to different treatment regimens in different tumour forms.
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23
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Petrovic V, Malin D, Cryns VL. αB-crystallin promotes oncogenic transformation and inhibits caspase activation in cells primed for apoptosis by Rb inactivation. Breast Cancer Res Treat 2013; 138:415-25. [PMID: 23471649 DOI: 10.1007/s10549-013-2465-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 02/21/2013] [Indexed: 11/29/2022]
Abstract
The retinoblastoma (Rb) tumor suppressor gene is frequently inactivated in cancer, resulting in deregulated activation of E2F transcription factors, which promote S-phase entry, p53-dependent and p53-independent apoptosis. Transformed cells evade p53-dependent apoptosis initiated by Rb inactivation by TP53 mutation. However, the mechanisms by which cancer cells circumvent p53-independent apoptosis in this context are poorly understood. Because Rb inactivation primes cells for apoptosis by p53-independent induction of procaspases, we postulated that αB-crystallin, an inhibitor of procaspase-3 activation, would suppress caspase activation in cells with combined Rb and p53 inactivation. Notably, αB-crystallin is commonly expressed in ER/PR/HER2 "triple-negative" breast carcinomas characterized by frequent Rb loss and TP53 mutation. We report that αB-crystallin (-/-) knock out (KO) MEFs immortalized by dominant negative (DN) p53 are resistant to transformation by the adenovirus E1A oncoprotein, which inactivates Rb, while wild-type (WT) MEFs are readily transformed by DN p53 and E1A. αB-crystallin (-/-) KO MEFs stably expressing DN p53 and E1A were more sensitive to chemotherapy-induced caspase-3 activation and apoptosis than the corresponding WT MEFs, despite comparable induction of procaspases by E1A. Similarly, silencing Rb in WT and αB-crystallin (-/-) KO MEFs immortalized by DN p53 increased procaspase levels and sensitized αB-crystallin (-/-) KO MEFs to chemotherapy. Furthermore, silencing αB-crystallin in triple-negative breast cancer cells, which lack Rb and express mutant p53, enhanced chemotherapy sensitivity compared to non-silencing controls. Our results indicate that αB-crystallin inhibits caspase activation in cells primed for apoptosis by Rb inactivation and plays a novel oncogenic role in the context of combined Rb and p53 inactivation.
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Affiliation(s)
- Vladimir Petrovic
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, 4144 MFCB, 1685 Highland Avenue, Madison, WI, 53705, USA
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24
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Lee TC, Gombos DS, Harbour JW, Mansfield NC, Murphree AL. Retinoblastoma. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00128-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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25
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Maddocks ODK, Berkers CR, Mason SM, Zheng L, Blyth K, Gottlieb E, Vousden KH. Serine starvation induces stress and p53-dependent metabolic remodelling in cancer cells. Nature 2012; 493:542-6. [PMID: 23242140 PMCID: PMC6485472 DOI: 10.1038/nature11743] [Citation(s) in RCA: 723] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 10/31/2012] [Indexed: 12/15/2022]
Abstract
Cancer cells acquire distinct metabolic adaptations to survive stress associated with tumour growth and to satisfy the anabolic demands of proliferation. The tumour suppressor protein p53 influences a range of cellular metabolic processes, including glycolysis1,2 oxidative phosphorylation3 (OXPHOS), glutaminolysis4,5 and anti-oxidant response6. In contrast to its role in promoting apoptosis during DNA damaging stress, p53 can promote cell survival during metabolic stress7, a function that may contribute not only to tumour suppression but also to non-cancer associated functions of p538. Here we show that cancer cells rapidly utilise exogenous serine and that serine deprivation triggered activation of the serine synthesis pathway (SSP) and rapidly suppressed aerobic glycolysis, resulting in increased flux to the TCA cycle. Transient p53-p21 activation and cell cycle arrest promoted cell survival efficiently channelling depleted serine stores to glutathione synthesis, preserving cellular anti-oxidant capacity. Cells lacking p53 failed to complete the response to serine depletion, resulting in oxidative stress, reduced viability and severely impaired proliferation. The role of p53 in supporting cancer cell proliferation under serine starvation was translated to an in vivo model, suggesting that serine depletion has a potential role in the treatment of p53-deficient tumours.
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Affiliation(s)
- Oliver D K Maddocks
- The Beatson Institute for Cancer Research, Switchback Road, Glasgow G61 1BD, UK
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26
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Ramakrishnan C, Subramanian V, Balamurugan K, Velmurugan D. Molecular dynamics simulations of retinoblastoma protein. J Biomol Struct Dyn 2012; 31:1277-92. [PMID: 23157310 DOI: 10.1080/07391102.2012.732345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tumor suppressor proteins play a crucial role in cell cycle regulation. Retinoblastoma protein (pRB) is one among them which regulates G1-S transition by binding with transcription factors. The activity of pRB is deregulated by cyclin dependent kinases-mediated hyper-phosphorylation and also due to cancer-derived mutations. In addition, it is also deactivated by binding of viral onco-proteins such as large T antigen, E1A, and E7. These viral proteins initially recognize pRB through their conserved LxCxE motif and facilitate dissociation of preexisting pRB-E2F complex. Based on these features, molecular dynamics (MD) simulation is performed for four different states of pRB for which the crystal structure is available. The unliganded/apo form and complex forms with E2F and E7 peptides reveal the molecular mechanism behind the activation and inactivation of pRB. In addition, the ternary complex of pRB with both E7 and E2F (for which no crystal structure is available) is modeled and simulated to understand the influence of binding of one ligand on the other. The variations in the three major factors such as conformational changes, inter- and intra-molecular interactions, and binding free energies between the apo and complex forms confirm the possibility for designing a small molecule inhibitor to inhibit pRB-E7 interactions without altering the prebound E2F. The present study deals with the molecular modeling and MD simulations of pRB in free and ligand-bound forms and confirms that pRB could be a valid target for the anticancer drug design when the cancer is induced by the viral onco-proteins and forms a clear base for designing E7 antagonists.
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Affiliation(s)
- C Ramakrishnan
- a Centre of Advanced Study in Crystallography and Biophysics, University of Madras , Maraimalai (Guindy) Campus, Chennai , 600025 , India
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27
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Abstract
Since cancer is one of the leading causes of death worldwide, there is an urgent need to find better treatments. Currently, the use of chemotherapeutics remains the predominant option for cancer therapy. However, one of the major obstacles for successful cancer therapy using these chemotherapeutics is that patients often do not respond or eventually develop resistance after initial treatment. Therefore identification of genes involved in chemotherapeutic response is critical for predicting tumour response and treating drug-resistant cancer patients. A group of genes commonly lost or inactivated are tumour suppressor genes, which can promote the initiation and progression of cancer through regulation of various biological processes such as cell proliferation, cell death and cell migration/invasion. Recently, mounting evidence suggests that these tumour suppressor genes also play a very important role in the response of cancers to a variety of chemotherapeutic drugs. In the present review, we will provide a comprehensive overview on how major tumour suppressor genes [Rb (retinoblastoma), p53 family, cyclin-dependent kinase inhibitors, BRCA1 (breast-cancer susceptibility gene 1), PTEN (phosphatase and tensin homologue deleted on chromosome 10), Hippo pathway, etc.] are involved in chemotherapeutic drug response and discuss their applications in predicting the clinical outcome of chemotherapy for cancer patients. We also propose that tumour suppressor genes are critical chemotherapeutic targets for the successful treatment of drug-resistant cancer patients in future applications.
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28
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Collard TJ, Urban BC, Patsos HA, Hague A, Townsend PA, Paraskeva C, Williams AC. The retinoblastoma protein (Rb) as an anti-apoptotic factor: expression of Rb is required for the anti-apoptotic function of BAG-1 protein in colorectal tumour cells. Cell Death Dis 2012; 3:e408. [PMID: 23059827 PMCID: PMC3481130 DOI: 10.1038/cddis.2012.142] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although the retinoblastoma-susceptibility gene RB1 is inactivated in a wide range of human tumours, in colorectal cancer, the retinoblastoma protein (Rb) function is often preserved and the RB locus even amplified. Importantly, we have previously shown that Rb interacts with the anti-apoptotic Bcl-2 associated athanogene 1 (BAG-1) protein, which is highly expressed in colorectal carcinogenesis. Here we show for the first time that Rb expression is critical for BAG-1 anti-apoptotic activity in colorectal tumour cells. We demonstrate that Rb expression not only increases the nuclear localisation of the anti-apoptotic BAG-1 protein, but that expression of Rb is required for inhibition of apoptosis by BAG-1 both in a γ-irradiated Saos-2 osteosarcoma cell line and colorectal adenoma and carcinoma cell lines. Further, consistent with the fact that nuclear BAG-1 has previously been shown to promote cell survival through increasing nuclear factor (NF)-κB activity, we demonstrate that the ability of BAG-1 to promote NF-κB activity is significantly inhibited by repression of Rb expression. Taken together, data presented suggest a novel function for Rb, promoting cell survival through regulating the function of BAG-1. As BAG-1 is highly expressed in the majority of colorectal tumours, targeting the Rb–BAG-1 complex to promote apoptosis has exciting potential for future therapeutic development.
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Affiliation(s)
- T J Collard
- Cancer Research UK Colorectal Tumour Biology Research Group, School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
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29
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Nilubol N, Zhang L, Shen M, Zhang YQ, He M, Austin CP, Kebebew E. Four clinically utilized drugs were identified and validated for treatment of adrenocortical cancer using quantitative high-throughput screening. J Transl Med 2012; 10:198. [PMID: 22999104 PMCID: PMC3493320 DOI: 10.1186/1479-5876-10-198] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 08/11/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Drug repurposing for cancer treatment is an emerging approach to discover clinically approved drugs that demonstrate antineoplastic effect. The effective therapeutics for patients with advanced adrenocortical carcinoma(ACC) are greatly needed. The objective of this study was to identify and validate drugs with antineoplastic effect in ACC cells using a novel quantitative high-throughput drug screening (qHTS) technique. METHODS A quantitative high-throughput proliferation assay of 2,816 clinically approved drugs was performed in the NCI-H295R ACC cell line. We validated the antiproliferative effect of candidate compounds in NCI-H295R cells. Further validation was performed in 3-dimensional multicellular aggregates (MCA) of NCI-H295R and SW-13 cell lines. RESULTS We identified 79 active compounds against ACC cells; 21 had an efficacy ≥ 60% and IC50 <1 μM. The top drug categories enriched were cardiotonic, antiseptic, and antineoplastic. We selected Bortezomib, ouabain, Methotrexate, pyrimethamine for validation. All had an antiproliferative effect in monolayer culture of NCI-H295R cells at clinical achievable serum level. Bortezomib and ouabain inhibited growth of MCA in both cell lines at a low concentration (10 fold below IC50). Methotrexate inhibited growth and caused disintegration of MCA in both cell lines at concentrations well below the maximum serum level (10 to 100 fold of IC50). Pyrimethamine caused growth inhibition in both cell lines at 10 fold of IC50 concentration. CONCLUSIONS qHTS of previously approved compounds is an effective and efficient method to identify anticancer drugs for a rare cancer such as ACC. We have validated the antineoplastic effect of Bortezomib, ouabain, Methotrexate and pyrimethamine, which could be translated into clinical trials in patients with locally advanced and/or metastatic ACC.
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Affiliation(s)
- Naris Nilubol
- Endocrine Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 10 Center Drive, MSC 1201, Bethesda, MD 20892, USA.
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Hot spots for allosteric regulation on protein surfaces. Cell 2012; 147:1564-75. [PMID: 22196731 DOI: 10.1016/j.cell.2011.10.049] [Citation(s) in RCA: 263] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 08/10/2011] [Accepted: 10/19/2011] [Indexed: 11/22/2022]
Abstract
Recent work indicates a general architecture for proteins in which sparse networks of physically contiguous and coevolving amino acids underlie basic aspects of structure and function. These networks, termed sectors, are spatially organized such that active sites are linked to many surface sites distributed throughout the structure. Using the metabolic enzyme dihydrofolate reductase as a model system, we show that: (1) the sector is strongly correlated to a network of residues undergoing millisecond conformational fluctuations associated with enzyme catalysis, and (2) sector-connected surface sites are statistically preferred locations for the emergence of allosteric control in vivo. Thus, sectors represent an evolutionarily conserved "wiring" mechanism that can enable perturbations at specific surface positions to rapidly initiate conformational control over protein function. These findings suggest that sectors enable the evolution of intermolecular communication and regulation.
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Vurusaner B, Poli G, Basaga H. Tumor suppressor genes and ROS: complex networks of interactions. Free Radic Biol Med 2012; 52:7-18. [PMID: 22019631 DOI: 10.1016/j.freeradbiomed.2011.09.035] [Citation(s) in RCA: 223] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 09/27/2011] [Accepted: 09/29/2011] [Indexed: 12/24/2022]
Abstract
Tumor suppressor genes regulate diverse cellular activities including DNA damage repair, cell cycle arrest, mitogenic signaling, cell differentiation, migration, and programmed cell death. In this review the tumor suppressor genes p53, FoxO, retinoblastoma (RB), p21, p16, and breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2) and their roles in oxidative stress are summarized with a focus on the links and interplay between their pathways and reactive oxygen species (ROS). The results of a number of studies have demonstrated an antioxidant role for tumor suppressor proteins, activating the expression of some well-known antioxidant genes in response to oxidative stress. On the other hand, recent studies have revealed a pro-oxidant role for p53 by which cellular ROS are increased by enhanced transcription of proapoptotic genes. A tightly regulated feedback loop between ROS and FoxO proteins, with ROS regulating FoxO activity through posttranslational modifications and protein interactions and FoxO controlling intracellular ROS levels, has been demonstrated. Furthermore, these studies have shown that FoxO transcription factors and p38 mitogen-activated protein kinases may interact with the RB pathway under stress conditions. In addition, cellular senescence studies established an unexpected role for ROS in inducing and maintaining senescence-induced tumor suppression that blocks cytokinesis to ensure senescent cells never divide again. p21 and p16 have been shown to act as tumor suppressor proteins and this function extends beyond cell cycle control and includes important roles in regulating oxidative stress. Consequently, these important interactions indicate a critical potential role for tumor suppressor genes in the cellular response against oxidative stress and emphasize links between ROS and tumor suppressor genes that might be therapeutic targets in oxidative damage-associated diseases.
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Affiliation(s)
- Beyza Vurusaner
- Biological Sciences and Bioengineering Program, Faculty of Natural Sciences and Engineering, Sabanci University, Istanbul, Turkey
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Nagashima T, Kim J, Li Q, Lydon JP, DeMayo FJ, Lyons KM, Matzuk MM. Connective tissue growth factor is required for normal follicle development and ovulation. Mol Endocrinol 2011; 25:1740-59. [PMID: 21868453 DOI: 10.1210/me.2011-1045] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Connective tissue growth factor (CTGF) is a cysteine-rich protein the synthesis and secretion of which are hypothesized to be selectively regulated by activins and other members of the TGF-β superfamily. To investigate the in vivo roles of CTGF in female reproduction, we generated Ctgf ovarian and uterine conditional knockout (cKO) mice. Ctgf cKO mice exhibit severe subfertility and multiple reproductive defects including disrupted follicle development, decreased ovulation rates, increased numbers of corpus luteum, and smaller but functionally normal uterine horns. Steroidogenesis is disrupted in the Ctgf cKO mice, leading to increased levels of serum progesterone. We show that disrupted follicle development is accompanied by a significant increase in granulosa cell apoptosis. Moreover, despite normal cumulus expansion, Ctgf cKO mice exhibit a significant decrease in oocytes ovulated, likely due to impaired ovulatory process. During analyses of mRNA expression, we discovered that Ctgf cKO granulosa cells show gene expression changes similar to our previously reported granulosa cell-specific knockouts of activin and Smad4, the common TGF-β family intracellular signaling protein. We also discovered a significant down-regulation of Adamts1, a progesterone-regulated gene that is critical for the remodeling of extracellular matrix surrounding granulosa cells of preovulatory follicles. These findings demonstrate that CTGF is a downstream mediator in TGF-β and progesterone signaling cascades and is necessary for normal follicle development and ovulation.
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Affiliation(s)
- Takashi Nagashima
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, Texas 77030, USA
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Khan MK, Khan N, Almasan A, Macklis R. Future of radiation therapy for malignant melanoma in an era of newer, more effective biological agents. Onco Targets Ther 2011; 4:137-48. [PMID: 21949607 PMCID: PMC3176173 DOI: 10.2147/ott.s20257] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The incidence of melanoma is rising. The primary initial treatment for melanoma continues to be wide local excision of the primary tumor and affected lymph nodes. Exceptions to wide local excision include cases where surgical excision may be cosmetically disfiguring or associated with increased morbidity and mortality. The role of definitive or adjuvant radiotherapy has largely been relegated to palliative measures because melanoma has been viewed as a prototypical radiotherapy-resistant cancer. However, the emerging clinical and radiobiological data summarized here suggests that many types of effective radiation therapy, such as radiosurgery for melanoma brain metastases, plaque brachytherapy for uveal melanoma, intensity modulated radiotherapy for melanoma of the head and neck, and adjuvant radiotherapy for selected high-risk, node-positive patients can improve outcomes. Similarly, although certain chemotherapeutic agents and biologics have shown limited responses, long-term control for unresectable tumors or disseminated metastatic disease has been rather disappointing. Recently, several powerful new biologics and treatment combinations have yielded new hope for this patient group. The recent identification of several clinically linked melanoma gene mutations involved in mitogen-activated protein kinase (MAPK) pathway such as BRAF, NRAS, and cKIT has breathed new life into the drive to develop more effective therapies. Some of these new therapeutic approaches relate to DNA damage repair inhibitors, cellular immune system activation, and pharmacological cell cycle checkpoint manipulation. Others relate to the investigation of more effective targeting and dosing schedules for underutilized therapeutics, such as radiotherapy. This paper summarizes some of these new findings and attempts to give some context to the renaissance in melanoma therapeutics and the potential role for multimodality regimens, which include certain types of radiotherapy as aids to locoregional control in sensitive tissues.
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Affiliation(s)
- Mohammad K Khan
- Taussig Cancer Institute, Lerner College of Medicine, Cleveland Clinic, Cleveland, OH, USA
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Taneja P, Zhu S, Maglic D, Fry EA, Kendig RD, Inoue K. Transgenic and knockout mice models to reveal the functions of tumor suppressor genes. Clin Med Insights Oncol 2011; 5:235-57. [PMID: 21836819 PMCID: PMC3153120 DOI: 10.4137/cmo.s7516] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cancer is caused by multiple genetic alterations leading to uncontrolled cell proliferation through multiple pathways. Malignant cells arise from a variety of genetic factors, such as mutations in tumor suppressor genes (TSGs) that are involved in regulating the cell cycle, apoptosis, or cell differentiation, or maintenance of genomic integrity. Tumor suppressor mouse models are the most frequently used animal models in cancer research. The anti-tumorigenic functions of TSGs, and their role in development and differentiation, and inhibition of oncogenes are discussed. In this review, we summarize some of the important transgenic and knockout mouse models for TSGs, including Rb, p53, Ink4a/Arf, Brca1/2, and their related genes.
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Affiliation(s)
| | - Sinan Zhu
- The Departments of Pathology
- Graduate Program in Molecular Medicine, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | - Dejan Maglic
- The Departments of Pathology
- Cancer Biology
- Graduate Program in Molecular Medicine, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA
| | | | | | - Kazushi Inoue
- The Departments of Pathology
- Cancer Biology
- Graduate Program in Molecular Medicine, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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Role and predictive strength of transglutaminase type 2 expression in premalignant lesions of the cervix. Mod Pathol 2011; 24:855-65. [PMID: 21441900 DOI: 10.1038/modpathol.2011.40] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The demonstration that type 2 transglutaminase (TG2) can incorporate polyamine into the E7 oncoprotein of human papillomavirus (HPV) type 18 has led to the hypothesis that TG2 can have a role in the host cellular response to HPV infection. The aim of this study was to investigate whether HPV-related pathology, in infected human cervical epithelium, was associated with modulation of TG2 expression. Normal controls and HPV-infected cervical biopsies were analyzed for the expression of TG2, and the findings were compared with lesion grade. The correlation between TG2 expression and p16, a marker for HPV-induced dysplasia, and the retinoblastoma protein (Rb), a target of the E7 protein of HPV, was also investigated. Results obtained showed that TG2 was absent in normal squamous mucosa, whereas it was present in 100% CIN I lesions. Low-grade lesions showed significantly higher TG2 expression than high-grade lesions (P<0.0001). In 94% of CIN I more than 50% of the cells were positive for TG2, with a strong staining intensity (+3), whereas a decreased staining intensity and a low number of positive cells were found in CIN II/III. In CIN I cases, both nuclear and cytoplasmic staining were found in cells exhibiting classical morphological features of HPV infection. In addition, during progression from low-grade squamous intraepithelial lesions to severe dysplasia, TG2 expression was inversely correlated with p16 (Pearson: -0.930), whereas a positive correlation was observed between the expression of TG2 and pRb (Pearson: 0.997). TG2 is expressed in HPV infection as an early phenomenon, not restricted to high-risk genotypes. TG2 upregulation is probably part of host cell reaction against HPV-induced tissue modification. It may act as a cellular antioxidant defense factor, playing an important role in counteracting oxidative damage in neoplastic disease.
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Khan N, Khan MK, Almasan A, Singh AD, Macklis R. The evolving role of radiation therapy in the management of malignant melanoma. Int J Radiat Oncol Biol Phys 2011; 80:645-54. [PMID: 21489712 DOI: 10.1016/j.ijrobp.2010.12.071] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 12/19/2010] [Accepted: 12/26/2010] [Indexed: 02/01/2023]
Abstract
The incidence of melanoma is rising in the United States, leading to an estimated 68,720 new diagnoses and 8,650 deaths annually. The natural history involves metastases to lymph nodes, lung, liver, brain, and often to other sites. Primary treatment for melanoma is surgical excision of the primary tumor and affected lymph nodes. The role of adjuvant or definitive radiation therapy in the treatment of melanoma remains controversial, because melanoma has traditionally been viewed as a prototypical radioresistant cancer. However, recent studies suggest that under certain clinical circumstances, there may be a significant role for radiation therapy in melanoma treatment. Stereotactic radiosurgery for brain metastases has shown effective local control. High dose per fraction radiation therapy has been associated with a lower rate of locoregional recurrence of sinonasal melanoma. Plaque brachytherapy has evolved into a promising alternative to enucleation at the expense of moderate reduction in visual acuity. Adjuvant radiation therapy following lymphadenectomy in node-positive melanoma prevents local and regional recurrence. The newer clinical data along with emerging radiobiological data indicate that radiotherapy is likely to play a greater role in melanoma management and should be considered as a treatment option.
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Affiliation(s)
- Niloufer Khan
- Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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Karanam NK, Grabarczyk P, Hammer E, Scharf C, Venz S, Gesell-Salazar M, Barthlen W, Przybylski GK, Schmidt CA, Völker U. Proteome analysis reveals new mechanisms of Bcl11b-loss driven apoptosis. J Proteome Res 2010; 9:3799-811. [PMID: 20513151 DOI: 10.1021/pr901096u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Bcl11b protein was shown to be important for a variety of functions such as T cell differentiation, normal development of central nervous system, and DNA damage response. Malignant T cells undergo apoptotic cell death upon BCL11B down-regulation, however, the detailed mechanism of cell death is not fully understood yet. Here we employed two-dimensional difference in-gel electrophoresis (2D-DIGE), mass spectrometry and cell biological experiments to investigate the role of Bcl11b in malignant T cell lines such as Jurkat and huT78. We provide evidence for the involvement of the mitochondrial apoptotic pathway and observed cleavage and fragments of known caspase targets such as myosin, spectrin, and vimentin. Our findings suggest an involvement of ERM proteins, which were up-regulated and phosphorylated upon Bcl11b down-regulation. Moreover, the levels of several proteins implicated in cell cycle entry, including DUT-N, CDK6, MCM4, MCM6, and MAT1 were elevated. Thus, the proteome data presented here confirm previous findings concerning the consequences of BCL11B knock-down and provide new insight into the mechanisms of cell death and cell cycle disturbances induced by Bcl11b depletion.
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Affiliation(s)
- Narasimha Kumar Karanam
- Interfakultäres Institut für Genetik und Funktionelle Genomforschung, Ernst-Moritz-Arndt-Universität Greifswald, Germany
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Delston RB, Matatall KA, Sun Y, Onken MD, Harbour JW. p38 phosphorylates Rb on Ser567 by a novel, cell cycle-independent mechanism that triggers Rb-Hdm2 interaction and apoptosis. Oncogene 2010; 30:588-99. [PMID: 20871633 PMCID: PMC3012146 DOI: 10.1038/onc.2010.442] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The retinoblastoma protein (Rb) inhibits both cell division and apoptosis, but the mechanism by which Rb alternatively regulates these divergent outcomes remains poorly understood. Cyclin dependent kinases (Cdks) promote cell division by phosphorylating and reversibly inactivating Rb by a hierarchical series of phosphorylation events and sequential conformational changes. The stress-regulated mitogen activated protein kinase (MAPK) p38 also phosphorylates Rb, but it does so in a cell cycle-independent manner that is associated with apoptosis rather than with cell division. Here, we show that p38 phosphorylates Rb by a novel mechanism that is distinct from that of Cdks. p38 bypasses the cell cycle-associated hierarchical phosphorylation and directly phosphorylates Rb on Ser567, which is not phosphorylated during the normal cell cycle. Phosphorylation by p38, but not Cdks, triggers an interaction between Rb and the human homologue of murine double minute 2 (Hdm2), leading to degradation of Rb, release of E2F1 and cell death. These findings provide a mechanistic explanation for how Rb regulates cell division and apoptosis through different kinases, and reveal how Hdm2 may functionally link the tumor suppressors Rb and p53.
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Affiliation(s)
- R B Delston
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, MO, USA
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Talos F, Moll UM. Role of the p53 family in stabilizing the genome and preventing polyploidization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 676:73-91. [PMID: 20687470 DOI: 10.1007/978-1-4419-6199-0_5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cellular defects resulting in chromosomal instability and aneuploidy are the most common features of human cancers. As a major tumor suppressor and intrinsic part of several cellular checkpoints, p53 contributes to maintenance of the stability of the genetic material, both in quality (ensures faithful replication) and quantity (preservation of diploidy). Although the exact trigger of p53 in case of numerical chromosomal aberrations is unknown, the absence of p53 allows polyploid cells to proliferate and generate unstable aneuploid progeny. A more recent addition to the p53 family, p73, emerged as an important contributor to genomic integrity when p53 is inactivated. p73 loss in p53-null background leads to a rapid increase in polyploidy and aneuploidy, markedly exceeding that caused by p53 loss alone. Constitutive deregulation of Cyclin-Cdk and p27/Kip1 activities and excess failure of the G2/M DNA damage checkpoint are important deficiencies associated with p73 loss.
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Affiliation(s)
- Flaminia Talos
- Department of Pathology, Health Science Center, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
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40
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Berge EO, Knappskog S, Geisler S, Staalesen V, Pacal M, Børresen-Dale AL, Puntervoll P, Lillehaug JR, Lønning PE. Identification and characterization of retinoblastoma gene mutations disturbing apoptosis in human breast cancers. Mol Cancer 2010; 9:173. [PMID: 20594292 PMCID: PMC2908580 DOI: 10.1186/1476-4598-9-173] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 07/01/2010] [Indexed: 12/29/2022] Open
Abstract
Background The tumor suppressor pRb plays a key role regulating cell cycle arrest, and disturbances in the RB1 gene have been reported in different cancer forms. However, the literature reports contradictory findings with respect to a pro - versus anti - apoptotic role of pRb, and the consequence of alterations in RB1 to chemotherapy sensitivity remains unclear. This study is part of a project investigating alterations in pivotal genes as predictive factors to chemotherapy sensitivity in breast cancer. Results Analyzing 73 locally advanced (stage III) breast cancers, we identified two somatic and one germline single nucleotide changes, each leading to amino acid substitution in the pRb protein (Leu607Ile, Arg698Trp, and Arg621Cys, respectively). This is the first study reporting point mutations affecting RB1 in breast cancer tissue. In addition, MLPA analysis revealed two large multiexon deletions (exons 13 to 27 and exons 21 to 23) with the exons 21-23 deletion occurring in the tumor also harboring the Leu607Ile mutation. Interestingly, Leu607Ile and Arg621Cys point mutations both localize to the spacer region of the pRb protein, a region previously shown to harbor somatic and germline mutations. Multiple sequence alignment across species indicates the spacer to be evolutionary conserved. All three RB1 point mutations encoded nuclear proteins with impaired ability to induce apoptosis compared to wild-type pRb in vitro. Notably, three out of four tumors harboring RB1 mutations displayed primary resistance to treatment with either 5-FU/mitomycin or doxorubicin while only 14 out of 64 tumors without mutations were resistant (p = 0.046). Conclusions Although rare, our findings suggest RB1 mutations to be of pathological importance potentially affecting sensitivity to mitomycin/anthracycline treatment in breast cancer.
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41
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Ladanyi M, Gorlick R. Molecular Pathology and Molecular Pharmacology of Osteosarcoma. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15513810009168647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Shanmugam MP, Lakshmi A, Biswas J, Krishnakumar S. Prognostic significance of Fas expression in retinoblastoma. Ocul Immunol Inflamm 2009; 11:107-13. [PMID: 14533029 DOI: 10.1076/ocii.11.2.107.15916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE The loss of Fas is believed to enhance metastatic spread in diverse human tumors. We studied the expression of Fas by immunohistochemistry in retinoblastomas and correlated the results clinicopathologically. METHODS Archival specimens of 76 retinoblastomas were included in this study. The tumors were divided into three groups: Group A (n = 21) comprising tumors with no invasion; Group B (n = 46) tumors with invasion of choroid (diffuse), optic nerve (post-laminar), and orbit; and Group C (n = 9) tumors with both invasion and metastasis. Sections were immunostained with monoclonal antibody CD95 (APO-1/Fas) and the immunoreactivity was assessed. RESULTS Negative immunoreactivity of Fas was observed in Group B and Group C tumors (p < 0.001). Poorly differentiated retinoblastomas showed a decreased Fas expression (p = 0.006). CONCLUSIONS Decreased expression of Fas is seen in aggressive tumors and tumors that are poorly differentiated. This preliminary observation deserves further investigation, which may then shed more light on the immune escape mechanisms of this tumor and thus enable novel therapeutic strategies.
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Affiliation(s)
- Mahesh P Shanmugam
- Medical and Vision Research Foundation, Sankara Nethralaya, Chennai, India
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43
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Askmalm MS, Carstensen J, Nordenskjöld B, Olsson B, Rutqvist LE, Skoog L, Stål O. Mutation and accumulation of p53 related to results of adjuvant therapy of postmenopausal breast cancer patients. Acta Oncol 2009; 43:235-44. [PMID: 15244246 DOI: 10.1080/02841860410029474] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
p53 protein accumulation and gene mutation have been implicated in resistance to cytotoxic treatment. This study was performed to further assess the predictive value of p53 in breast cancer. Postmenopausal patients were randomized to adjuvant chemotherapy with cyclophosphamide, metothrexate, or 5-fluorouracil (CMF) vs. postoperative radiotherapy. The patients were also randomized to adjuvant tamoxifen vs. no endocrine treatment. Immunohistochemistry (IHC) and single-strand conformation polymorphism (SSCP), followed by direct sequencing, was performed. The p53 altered group, regarded as positive for p53 gene mutation and/or p53 protein accumulation, tended to benefit more from CMF than from radiotherapy as compared with others regarding distant recurrences. In the group lacking p53 alteration there was a significantly decreased local recurrence rate in the radiotherapy group as compared with the CMF group (RR = 0.24, 95% CI = 0.083 0.62), whereas no benefit from radiotherapy was found for patients showing p53 alterations. Tamoxifen significantly decreased the rate of distant recurrence for estrogen receptor-positive patients with no apparent difference in relation to p53 alteration. It is suggested that p53 alteration indicates benefit from CMF compared with radiotherapy regarding distant recurrence-free survival and the best local control with radiotherapy is achieved in the absence of p53 alteration. Finally, altered p53 status is probably not a marker of resistance to tamoxifen.
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Affiliation(s)
- Marie Stenmark Askmalm
- Department of Biomedicine and Surgery, Division of Oncology, Faculty of Health, Sciences, Linköping University, Linköping, Sweden.
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Liu H, Knabb JR, Spike BT, Macleod KF. Elevated poly-(ADP-ribose)-polymerase activity sensitizes retinoblastoma-deficient cells to DNA damage-induced necrosis. Mol Cancer Res 2009; 7:1099-109. [PMID: 19584263 DOI: 10.1158/1541-7786.mcr-08-0439] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The retinoblastoma (Rb) tumor suppressor is a key regulator of cell cycle checkpoints but also protects against cell death induced by stresses such as DNA damage and death receptor ligation. We report here that cell death of Rb-deficient cells exposed to key genotoxic agents was associated with increased expression of S phase-specific E2F target genes and cell death consistently occurred in the S phase of the cell cycle. Cell cycle arrest induced by serum starvation prevented S phase entry, attenuated DNA damage, and promoted survival, suggesting that Rb-null cells die due to a failure to prevent S phase entry. DNA damage-induced death of Rb-null cells was associated with nucleotide depletion, higher activity of poly-ADP-ribose-polymerase (Parp), and cell death that was primarily necrotic. Knockdown of Parp-1 or chemical inhibition of Parp activity prevented nucleotide depletion and restored the viability of Rb-deficient cells to wild-type levels. Furthermore, chemical inhibition of Parp activity in vivo attenuated the cytotoxic effects of cisplatin against Rb-deficient tumors, arguing that Parp inhibitors should not be used therapeutically in combination with genotoxic drugs against tumors that are inactivated for the Rb tumor suppressor.
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Affiliation(s)
- Huiping Liu
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, The University of Chicago, Chicago, Illinois 60637, USA
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Wu Z, Zheng S, Yu Q. The E2F family and the role of E2F1 in apoptosis. Int J Biochem Cell Biol 2009; 41:2389-97. [PMID: 19539777 DOI: 10.1016/j.biocel.2009.06.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 06/02/2009] [Accepted: 06/08/2009] [Indexed: 12/22/2022]
Abstract
The E2F family of transcription factors plays a pivotal role in the regulation of cellular proliferation and differentiation. Although the deregulation of E2Fs is considered an oncogenic event that predisposes immortalized cells to transformation, paradoxically, E2F1 is also equipped with an ability to induce apoptosis under certain cellular contexts. It has become evident that E2Fs, in particular E2F1, participate in many aspects of the apoptotic process, either by acting alone or in cooperation with other factors, such as p53, to protect organisms from tumor development in the face of oncogenic lesions. Given the frequent inactivation of p53 in human cancers, the E2F1-induced apoptosis pathway is rapidly gaining attention as a key mechanism to compensate the loss of p53 in human tumors. In this review, we will focus on the recent progress in our understanding of E2F1-mediated apoptosis and discuss how these discoveries can be translated into potential therapeutic intervention.
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Affiliation(s)
- Zhenlong Wu
- Cancer Biology and Pharmacology, Genome Institute of Singapore, A*Star (Agency for Science, Technology and Research), Biopolis 02-01, Singapore 138672, Singapore
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Ianari A, Natale T, Calo E, Ferretti E, Alesse E, Screpanti I, Haigis K, Gulino A, Lees JA. Proapoptotic function of the retinoblastoma tumor suppressor protein. Cancer Cell 2009; 15:184-94. [PMID: 19249677 PMCID: PMC2880703 DOI: 10.1016/j.ccr.2009.01.026] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 08/03/2008] [Accepted: 01/26/2009] [Indexed: 12/25/2022]
Abstract
The retinoblastoma protein (pRB) tumor suppressor blocks cell proliferation by repressing the E2F transcription factors. This inhibition is relieved through mitogen-induced phosphorylation of pRB, triggering E2F release and activation of cell-cycle genes. E2F1 can also activate proapoptotic genes in response to genotoxic or oncogenic stress. However, pRB's role in this context has not been established. Here we show that DNA damage and E1A-induced oncogenic stress promote formation of a pRB-E2F1 complex even in proliferating cells. Moreover, pRB is bound to proapoptotic promoters that are transcriptionally active, and pRB is required for maximal apoptotic response in vitro and in vivo. Together, these data reveal a direct role for pRB in the induction of apoptosis in response to genotoxic or oncogenic stress.
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Affiliation(s)
- Alessandra Ianari
- David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139
- Department of Experimental Medicine, La Sapienza University of Rome, 00161 Rome, Italy
| | - Tiziana Natale
- Department of Experimental Medicine, La Sapienza University of Rome, 00161 Rome, Italy
| | - Eliezer Calo
- David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139
| | - Elisabetta Ferretti
- Department of Experimental Medicine, La Sapienza University of Rome, 00161 Rome, Italy
| | - Edoardo Alesse
- Department of Experimental Medicine, University of L’Aquila, L’Aquila, Italy
| | - Isabella Screpanti
- Department of Experimental Medicine, La Sapienza University of Rome, 00161 Rome, Italy
| | - Kevin Haigis
- Massachusetts General Hospital, Center for Cancer Research, Charlestown, MA 02129
| | - Alberto Gulino
- Department of Experimental Medicine, La Sapienza University of Rome, 00161 Rome, Italy
- Neuromed Institute, 86077 Pozzilli, Italy
- Corresponding authors: (A.G.) Department of Experimental Medicine and Pathology, La Sapienza, University of Rome, Viale Regina Elena 324, Rome, Italy 00161, Tel. (39 06) 446 4021, . (J.A.L.) MIT Koch Institute, E17-517B, 40 Ames St., Cambridge, MA 02139, (617) 252 1972,
| | - Jacqueline A. Lees
- David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139
- Corresponding authors: (A.G.) Department of Experimental Medicine and Pathology, La Sapienza, University of Rome, Viale Regina Elena 324, Rome, Italy 00161, Tel. (39 06) 446 4021, . (J.A.L.) MIT Koch Institute, E17-517B, 40 Ames St., Cambridge, MA 02139, (617) 252 1972,
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Liem DA, Zhao P, Angelis E, Chan SS, Zhang J, Wang G, Berthet C, Kaldis P, Ping P, MacLellan WR. Cyclin-dependent kinase 2 signaling regulates myocardial ischemia/reperfusion injury. J Mol Cell Cardiol 2008; 45:610-6. [PMID: 18692063 PMCID: PMC2603425 DOI: 10.1016/j.yjmcc.2008.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 06/30/2008] [Accepted: 07/02/2008] [Indexed: 01/22/2023]
Abstract
Ischemia/reperfusion (I/R) injury to the heart is accompanied by the upregulation and posttranslational modification of a number of proteins normally involved in regulating cell cycle progression. Two such proteins, cyclin-dependent kinase-2 (Cdk2) and its downstream target, the retinoblastoma gene product (Rb), also play a critical role in the control of apoptosis. Myocardial ischemia activates Cdk2, resulting in the phosphorylation and inactivation of Rb. Blocking Cdk2 activity reduces apoptosis in cultured cardiac myocytes. Genetic or pharmacological inhibition of Cdk2 activity in vivo during I/R injury led to a 36% reduction in infarct size (IFS), when compared to control mice, associated with a reduction in apoptotic myocytes. To confirm that Rb was the critical target in Cdk2-mediated I/R injury, we determined the consequences of I/R injury in cardiac-specific Rb-deficient mice (CRb(L/L)). IFS was increased 140% in CRb(L/L) mice compared to CRb+/+ controls. TUNEL positive nuclei and caspase-3 activity were augmented by 92% and 36%, respectively, following injury in the CRb(L/L) mice demonstrating that loss of Rb in the heart significantly exacerbates I/R injury. These data suggest that Cdk2 signaling pathways are critical regulators of cardiac I/R injury in vivo and support a cardioprotective role for Rb.
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Affiliation(s)
- David A. Liem
- The Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - Peng Zhao
- The Cardiovascular Research Laboratory, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - Ekaterini Angelis
- The Cardiovascular Research Laboratory, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - Shing S. Chan
- The Cardiovascular Research Laboratory, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - Jun Zhang
- The Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - Guangwu Wang
- The Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - Cyril Berthet
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Philipp Kaldis
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, 21702
| | - Peipei Ping
- The Cardiovascular Research Laboratory, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
- The Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
| | - W. Robb MacLellan
- The Cardiovascular Research Laboratory, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
- The Cardiovascular Research Laboratory, Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, 90095
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48
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Macleod KF. The role of the RB tumour suppressor pathway in oxidative stress responses in the haematopoietic system. Nat Rev Cancer 2008; 8:769-81. [PMID: 18800074 PMCID: PMC2989879 DOI: 10.1038/nrc2504] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Exposure to pro-oxidants and defects in the repair of oxidative base damage are associated with disease and ageing and also contribute to the development of anaemia, bone marrow failure and haematopoietic malignancies. This Review assesses emerging data indicative of a specific role for the RB tumour suppressor pathway in the response of the haematopoietic system to oxidative stress. This is mediated through signalling pathways that involve DNA damage sensors, forkhead box O (Foxo) transcription factors and p38 mitogen-activated protein kinases and has downstream consequences for cell cycle progression, antioxidant capacity, mitochondrial mass and cellular metabolism.
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Affiliation(s)
- Kay F Macleod
- Ben May Department for Cancer Research, Committee on Cancer Biology, University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.
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Abstract
The retinoblastoma tumour suppressor (RB) is a crucial regulator of cell-cycle progression that is invoked in response to a myriad of anti-mitogenic signals. It has been hypothesized that perturbations of the RB pathway confer a synonymous proliferative advantage to tumour cells; however, recent findings demonstrate context-specific outcomes associated with such lesions. Particularly, loss of RB function is associated with differential response to wide-ranging therapeutic agents. Thus, the status of this tumour suppressor may be particularly informative in directing treatment regimens.
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Affiliation(s)
- Erik S Knudsen
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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Araki K, Ahmad SM, Li G, Bray DA, Saito K, Wang D, Wirtz U, Sreedharan S, O'Malley BW, Li D. Retinoblastoma RB94 enhances radiation treatment of head and neck squamous cell carcinoma. Clin Cancer Res 2008; 14:3514-9. [PMID: 18519784 DOI: 10.1158/1078-0432.ccr-07-4538] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To assess whether adenovirus-mediated retinoblastoma 94 (Ad-RB94) transgene expression enhances efficacy of radiation therapy (XRT) of human head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN The HNSCC cell lines (JHU006 and JHU012) were treated in vitro and in a nude mouse xenograft model with Ad-RB94, Ad-DL312 control vector, or untreated as mock control. Cell viability and tumor growth were evaluated and combined RB94/XRT antitumor activity was analyzed by measuring DNA double-strand breaks, apoptosis-associated early DNA fragmentation, and levels of RB-regulated cell cycle progression E2F1 transcription factor. RESULTS Ad-RB94/XRT resulted in significant HNSCC cell growth inhibition compared with XRT alone or Ad-RB94 alone in vitro and caused significant tumor regression compared with XRT alone and Ad-DL312/XRT in JHU006 and with XRT alone, Ad-DL312/XRT and Ad-RB94 alone in JHU012 in vivo. Neutral comet analysis revealed that DNA damage was significantly elevated in cells treated with Ad-RB94 alone and Ad-RB94/XRT. Tumors treated with Ad-RB94 alone showed a striking increase in early apoptosis DNA fragmentation, and DNA fragmentation was further enhanced with XRT. In addition, levels of E2F1 were up-regulated by Ad-RB94/XRT combination, whereas Ad-RB94 alone did not affect E2F1 levels and XRT alone led to down-regulation of E2F1. CONCLUSIONS A potent antitumor effect has been observed after Ad-RB94/XRT combination treatment in HNSCC xenograft tumors. Enhanced tumor regression correlated with increased apoptosis. Ad-RB94 treatment enhances the efficacy of XRT through tumor cell sensitization by arresting the cells at the radiation-sensitive G(2)-M cell cycle and via E2F1 up-regulation.
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Affiliation(s)
- Koji Araki
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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