1
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Chen G, Xu JY, Chen J, Zhang JX, Zhou J, Liang Y, Ding XF. Loss of PIG3 increases HIF-1α level by promoting protein synthesis via mTOR pathway in renal cell carcinoma cells. Oncotarget 2017; 7:27176-84. [PMID: 27029070 PMCID: PMC5053640 DOI: 10.18632/oncotarget.8401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 03/16/2016] [Indexed: 12/27/2022] Open
Abstract
PIG3 is a target of the tumor suppressor p53 and is thought to be involved in p53-mediated cell apoptosis. Although PIG3 is similar to oxidoreductases involved in generating ROS, whether PIG3 would regulate HIF-1α was never characterized directly. Here we demonstrated that knockdown of PIG3 by transfecting with specific siRNA could increase the expression of HIF-1α in several human cancer cell lines, including CAKI, FTC-133 and A549. It indicates that PIG3 may be involved in the regulation of HIF-1α. Furthermore, we revealed that PIG3-siliencing increased HIF-1α protein level through promoting its protein biosynthesis via mTOR pathway. In addition, the effect of PIG3 on the production of HIF-1α was further related to VEGF secretion and cell migration. PIG3-downregulation increased the secretion of VEGF and promoted the migration of renal cancer cells obviously. Taken together, these data suggest that PIG3 was involved in HIF-1α regulation, and reveal a novel signaling pathway of PIG3/HIF-1α in the regulation of cell migration in renal cell carcinoma.
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Affiliation(s)
- Guang Chen
- School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou, Zhejiang, China.,Institute of Tumor, Taizhou University, Taizhou, Zhejiang, China
| | - Jin-Ye Xu
- Laboratory of Cancer Biology, Provincial Key Lab of Biotherapy in Zhejiang, Sir Runrun Shaw Hospital, Medical School of Zhejiang University, Hangzhou, China.,Taizhou Municipal Hospital, Taizhou, Zhejiang, China
| | - Jie Chen
- School of Medicine, Taizhou University, Taizhou, Zhejiang, China
| | - Jian-Xin Zhang
- School of Medicine, Taizhou University, Taizhou, Zhejiang, China
| | - Jun Zhou
- School of Medicine, Taizhou University, Taizhou, Zhejiang, China
| | - Yong Liang
- Taizhou Municipal Hospital, Taizhou, Zhejiang, China.,School of Medicine, Taizhou University, Taizhou, Zhejiang, China
| | - Xiao-Fei Ding
- School of Medicine, Taizhou University, Taizhou, Zhejiang, China
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2
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Jin M, Park SJ, Kim SW, Kim HR, Hyun JW, Lee JH. PIG3 Regulates p53 Stability by Suppressing Its MDM2-Mediated Ubiquitination. Biomol Ther (Seoul) 2017; 25:396-403. [PMID: 28605833 PMCID: PMC5499618 DOI: 10.4062/biomolther.2017.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 04/20/2017] [Accepted: 04/22/2017] [Indexed: 11/24/2022] Open
Abstract
Under normal, non-stressed conditions, intracellular p53 is continually ubiquitinated by MDM2 and targeted for degradation. However, in response to severe genotoxic stress, p53 protein levels are markedly increased and apoptotic cell death is triggered. Inhibiting the ubiquitination of p53 under conditions where DNA damage has occurred is therefore crucial for preventing the development of cancer, because if cells with severely damaged genomes are not removed from the population, uncontrolled growth can result. However, questions remain about the cellular mechanisms underlying the regulation of p53 stability. In this study, we show that p53-inducible gene 3 (PIG3), which is a transcriptional target of p53, regulates p53 stability. Overexpression of PIG3 stabilized both endogenous and transfected wild-type p53, whereas a knockdown of PIG3 lead to a reduction in both endogenous and UV-induced p53 levels in p53-proficient human cancer cells. Using both in vivo and in vitro ubiquitination assays, we found that PIG3 suppressed both ubiquitination- and MDM2-dependent proteasomal degradation of p53. Notably, we demonstrate that PIG3 interacts directly with MDM2 and promoted MDM2 ubiquitination. Moreover, elimination of endogenous PIG3 in p53-proficient HCT116 cells decreased p53 phosphorylation in response to UV irradiation. These results suggest an important role for PIG3 in regulating intracellular p53 levels through the inhibition of p53 ubiquitination.
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Affiliation(s)
- Min Jin
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju 61452, Republic of Korea
| | - Seon-Joo Park
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Republic of Korea.,Department of Premedical Sciences, Chosun University School of Medicine, Gwangju 61452, Republic of Korea
| | - Seok Won Kim
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Republic of Korea.,Department of Neurosurgery, Chosun University School of Medicine, Gwangju 61452, Republic of Korea
| | - Hye Rim Kim
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju 61452, Republic of Korea
| | - Jin Won Hyun
- Department of Biochemistry, School of Medicine, Jeju National University, Jeju 63243, Republic of Korea
| | - Jung-Hee Lee
- Laboratory of Genomic Instability and Cancer therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Republic of Korea.,Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju 61452, Republic of Korea
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3
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Park SJ, Kim HB, Kim J, Park S, Kim SW, Lee JH. The oncogenic effects of p53-inducible gene 3 ( PIG3) in colon cancer cells. Korean J Physiol Pharmacol 2017; 21:267-273. [PMID: 28280421 PMCID: PMC5343061 DOI: 10.4196/kjpp.2017.21.2.267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 01/31/2017] [Accepted: 02/03/2017] [Indexed: 12/02/2022]
Abstract
The p53-inducible gene 3 (PIG3), initially identified as a gene downstream of p53, plays an important role in the apoptotic process triggered by p53-mediated reactive oxygen species (ROS) production. Recently, several studies have suggested that PIG3 may play a role in various types of cancer. However, the functional significance of PIG3 in cancer remains unclear. Here, we found that PIG3 was highly expressed in human colon cancer cell lines compared to normal colonderived fibroblasts. Therefore, we attempted to elucidate the functional role of PIG3 in colon cancer. PIG3 overexpression increases the colony formation, migration and invasion ability of HCT116 colon cancer cells. Conversely, these tumorigenic abilities were significantly decreased in in vitro studies with PIG3 knockdown HCT116 cells. PIG3 knockdown also attenuated the growth of mouse xenograft tumors. These results demonstrate that PIG3 is associated with the tumorigenic potential of cancer cells, both in vitro and in vivo, and could play a key oncogenic role in colon cancer.
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Affiliation(s)
- Seon-Joo Park
- Laboratory of Genomic Instability and Cancer Therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Korea.; Department of Premedical Sciences, Chosun University School of Medicine, Gwangju 61452, Korea
| | - Hong Beum Kim
- Laboratory of Genomic Instability and Cancer Therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Korea.; Department of Premedical Sciences, Chosun University School of Medicine, Gwangju 61452, Korea
| | - Jeeho Kim
- Laboratory of Genomic Instability and Cancer Therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Korea
| | - Sanggon Park
- Department of Internal Medicine, Hemato-oncology, Chosun University School of Medicine, Gwangju 61452, Korea
| | - Seok Won Kim
- Department of Neurosurgery, Chosun University School of Medicine, Gwangju 61452, Korea
| | - Jung-Hee Lee
- Laboratory of Genomic Instability and Cancer Therapeutics, Cancer Mutation Research Center, Chosun University School of Medicine, Gwangju 61452, Korea.; Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju 61452, Korea
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4
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Zhang W, Luo J, Chen F, Yang F, Song W, Zhu A, Guan X. BRCA1 regulates PIG3-mediated apoptosis in a p53-dependent manner. Oncotarget 2016; 6:7608-18. [PMID: 25797244 PMCID: PMC4480703 DOI: 10.18632/oncotarget.3263] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 01/31/2015] [Indexed: 11/25/2022] Open
Abstract
BRCA1 plays a key role in the regulation of p53-dependent target gene transcription activation. Meanwhile, the p53 inducible gene 3 (PIG3) is a downstream target of p53 and is involved in p53-initiated apoptosis. However, little is known about whether BRCA1 can regulate PIG3-mediated apoptosis. Using a tissue microarray containing 149 breast cancer patient samples, we found that BRCA1 and PIG3 expression status were significantly positively correlated (r = 0.678, P < 0.001) and identified a significant positive correlation between high expression of BRCA1 and/or PIG3 and overall survival (OS). Moreover, we reveal that overexpression of BRCA1 significantly increased expression of PIG3 in cells with intact p53, whereas no increase in PIG3 was observed in p53-null MDA-MB-157 cells and p53-depleted HCT116p53−/− cells. Meanwhile, ectopic expression of BRCA1 could not lead to an increase expression level of prohibitin (PHB), which we have previously identified to induce PIG3-mediated apoptosis. Finally, ChIP analysis revealed that PHB can bind to the PIG3 promoter and activate PIG3 transcription independent of p53, although p53 presence did enhance this process. Taken together, our findings suggest that BRCA1 regulates PIG3-mediated apoptosis in a p53-dependent manner, and that PIG3 expression is associated with a better OS in breast cancer patients.
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Affiliation(s)
- Wenwen Zhang
- Department of Medical Oncology, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Jiayan Luo
- Department of Medical Oncology, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Fengxia Chen
- Department of Medical Oncology, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Fang Yang
- Department of Medical Oncology, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China
| | - Wei Song
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Southern Medical University, Guangzhou 510282, China
| | - Aiyu Zhu
- Department of Medical Oncology, Jinling Hospital, School of Medicine, Southern Medical University, Guangzhou 510282, China
| | - Xiaoxiang Guan
- Department of Medical Oncology, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.,Department of Medical Oncology, Jinling Hospital, School of Medicine, Southern Medical University, Guangzhou 510282, China
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5
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Zhang W, Cao L, Sun Z, Xu J, Tang L, Chen W, Luo J, Yang F, Wang Y, Guan X. Skp2 is over-expressed in breast cancer and promotes breast cancer cell proliferation. Cell Cycle 2016; 15:1344-51. [PMID: 27111245 DOI: 10.1080/15384101.2016.1160986] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The F box protein Skp2 is oncogenic. Skp2 and Skp2B, an isoform of Skp2 are overexpressed in breast cancer. However, little is known regarding the mechanism by which Skp2B promotes the occurrence and development of breast cancer. Here, we determined the expression and clinical outcomes of Skp2 in breast cancer samples and cell lines using breast cancer database, and investigated the role of Skp2 and Skp2B in breast cancer cell growth, apoptosis and cell cycle arrest. We obtained Skp2 is significantly overexpressed in breast cancer samples and cell lines, and high Skp2 expression positively correlated with poor prognosis of breast cancer. Both Skp2 and Skp2B could promote breast cancer cell proliferation, inhibit cell apoptosis, change the cell cycle distribution and induce the increased S phase cells and therefore induce cell proliferation in breast cancer cells. Moreover, the 2 isoforms could both suppress PIG3 expression via independent pathways in the breast cancer cells. Skp2 suppressed p53 and inhibited PIG3-induced apoptosis, while Skp2B attenuated the function of PIG3 by inhibiting PHB. Our results indicate that Skp2 and Skp2B induce breast cancer cell development and progression, making Skp2 and Skp2B potential molecular targets for breast cancer therapy.
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Affiliation(s)
- Wenwen Zhang
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Lulu Cao
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Zijia Sun
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Jing Xu
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Lin Tang
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Weiwei Chen
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Jiayan Luo
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Fang Yang
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China
| | - Yucai Wang
- b Department of Medicine ; Rutgers New Jersey Medical School , Newark , NJ , USA
| | - Xiaoxiang Guan
- a Department of Medical Oncology , Jinling Hospital , Medical School of Nanjing University , Nanjing , China.,c Department of Medical Oncology, Jinling Hospital, Nanjing Medical University, Nanjing, China
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6
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Herraiz C, Crosas-Molist E, Sanz-Moreno V. Reactive oxygen species and tumor dissemination: Allies no longer. Mol Cell Oncol 2016; 3:e1127313. [PMID: 27308633 PMCID: PMC4905421 DOI: 10.1080/23723556.2015.1127313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 11/25/2015] [Accepted: 11/26/2015] [Indexed: 12/20/2022]
Abstract
For decades, reactive oxygen species (ROS) linked to oxidative stress have been suggested to promote carcinogenesis. However, we and others have demonstrated a protective role for ROS in metastatic dissemination. These recent studies partly explain the large failure observed in clinical trials using antioxidants for cancer prevention.
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Affiliation(s)
- Cecilia Herraiz
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London , London SE1 1UL, UK
| | - Eva Crosas-Molist
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London , London SE1 1UL, UK
| | - Victoria Sanz-Moreno
- Tumour Plasticity Laboratory, Randall Division of Cell and Molecular Biophysics, New Hunt's House, Guy's Campus, King's College London , London SE1 1UL, UK
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7
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Allen MA, Andrysik Z, Dengler VL, Mellert HS, Guarnieri A, Freeman JA, Sullivan KD, Galbraith MD, Luo X, Kraus WL, Dowell RD, Espinosa JM. Global analysis of p53-regulated transcription identifies its direct targets and unexpected regulatory mechanisms. eLife 2014; 3:e02200. [PMID: 24867637 PMCID: PMC4033189 DOI: 10.7554/elife.02200] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The p53 transcription factor is a potent suppressor of tumor growth. We report here an analysis of its direct transcriptional program using Global Run-On sequencing (GRO-seq). Shortly after MDM2 inhibition by Nutlin-3, low levels of p53 rapidly activate ∼200 genes, most of them not previously established as direct targets. This immediate response involves all canonical p53 effector pathways, including apoptosis. Comparative global analysis of RNA synthesis vs steady state levels revealed that microarray profiling fails to identify low abundance transcripts directly activated by p53. Interestingly, p53 represses a subset of its activation targets before MDM2 inhibition. GRO-seq uncovered a plethora of gene-specific regulatory features affecting key survival and apoptotic genes within the p53 network. p53 regulates hundreds of enhancer-derived RNAs. Strikingly, direct p53 targets harbor pre-activated enhancers highly transcribed in p53 null cells. Altogether, these results enable the study of many uncharacterized p53 target genes and unexpected regulatory mechanisms.DOI: http://dx.doi.org/10.7554/eLife.02200.001.
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Affiliation(s)
- Mary Ann Allen
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States BioFrontiers Institute, Boulder, United States Computational Biosciences Program, University of Colorado, Denver-Anschutz Medical Campus, Aurora, United States
| | - Zdenek Andrysik
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Veronica L Dengler
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Hestia S Mellert
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Anna Guarnieri
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Justin A Freeman
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Kelly D Sullivan
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Matthew D Galbraith
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
| | - Xin Luo
- Signalling and Gene Regulation Laboratory, Cecil H and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, United States
| | - W Lee Kraus
- Signalling and Gene Regulation Laboratory, Cecil H and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, United States
| | - Robin D Dowell
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States BioFrontiers Institute, Boulder, United States
| | - Joaquin M Espinosa
- Howard Hughes Medical Institute, University of Colorado, Boulder, Boulder, United States Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Boulder, United States
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8
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Guan X, Liu Z, Wang L, Johnson DG, Wei Q. Identification of prohibitin and prohibiton as novel factors binding to the p53 induced gene 3 ( PIG3) promoter (TGYCC)(15) motif. Biochem Biophys Res Commun 2014; 443:1239-44. [PMID: 24388982 DOI: 10.1016/j.bbrc.2013.12.124] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 12/23/2013] [Indexed: 01/30/2023]
Abstract
The promoter of p53 induced gene 3 (PIG3) contains a variable number of tandem repeats (VNTRs) of pentanucleotides (TGYCC)n that is known as a p53 binding site. In this study, we investigated whether other potential molecules could bind to this PIG3 promoter (TGYCC)n motif. Ligand-chromatography combined with liquid chromatography-tandem mass spectrometry analyses indicated direct interactions of prohibitin and/or prohibiton with the (TGYCC)15 motif, which was confirmed by electrophoretic mobility shift assay and super-gel shift analysis with anti-prohibitin and anti-prohibiton antibodies. Using the chromatin immunopercipipation assay, we further demonstrated that prohibitin and prohibiton associated with the (TGYCC)15 motif in vivo regardless of the p53 status and apoptotic stress. We also found that prohibitin and prohibiton up-regulated PIG3 transcription independent of p53, although p53 obviously enhanced this process, and that the knock-down of prohibitin and prohibiton inhibited camptothecin-induced apoptosis. Taken together, our findings suggest that prohibitin and prohibiton contribute to PIG3-mediated apoptosis by binding to the PIG3 promoter (TGYCC)15 motif.
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Affiliation(s)
- Xiaoxiang Guan
- Department of Medical Oncology, Jinling Hospital, Medical School of Nanjing University, Nanjing 210002, China.
| | - Zhensheng Liu
- Duke Cancer Institute, Duke University School of Medicine, USA
| | - Luo Wang
- Department of Internal Medicine, Division of Hematology and Oncology, Comprehensive Cancer Center, University of Michigan Medical School, USA
| | - David G Johnson
- Department of Molecular Carcinogenesis, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Qingyi Wei
- Duke Cancer Institute, Duke University School of Medicine, USA.
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9
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Li B, Shang ZF, Yin JJ, Xu QZ, Liu XD, Wang Y, Zhang SM, Guan H, Zhou PK. PIG3 functions in DNA damage response through regulating DNA-PKcs homeostasis. Int J Biol Sci 2013; 9:425-34. [PMID: 23678292 PMCID: PMC3654439 DOI: 10.7150/ijbs.6068] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 04/22/2013] [Indexed: 11/29/2022] Open
Abstract
The p53-inducible gene 3 (PIG3) recently has been reported to be a new player in DNA damage signaling and response, but the crucial mechanism remains unclear. In the present study, the potential mechanism of PIG3 participation in the DNA damage response induced by ionizing radiation (IR) was investigated in multiple cell lines with depleted expression of PIG3 transiently or stably by the small interference RNA and lentivirus-mediated shRNA expression strategies. PIG3 knockdown led to an abnormal DNA damage response, including decreased IR-induced phosphorylation of H2AX, Chk1, Chk2 and Kap-1 as well as a prolonged G2-M arrest and aberrant mitotic progression. Notably, PIG3 knockdown resulted in a striking depression of cellular DNA-PKcs protein level, and was accompanied by a downregulation of ATM. Re-expression of PIG3 effectively rescued the depression of DNA-PKcs in PIG3-depleted cells. This negative regulation of DNA-PKcs by depleting PIG3 seemed to take place at the translational level but not at the levels of transcription or protein degradation. However, a compensatory feedback of increased mRNA expression of DNA-PKcs was formed in PIG3-depleted cells after a few passages or cell cycles of subculture, which led the recovery of the DNA-PKcs protein level and the consequent recovered efficiency of the DNA damage response. These results provide a new insight into the mechanism of PIG3's functioning in DNA damage signaling and the regulation network of cellular DNA-PKcs expression homeostasis.
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Affiliation(s)
- Bing Li
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Haidian District, Beijing 100850, China
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