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Ralec C, Henry E, Lemor M, Killelea T, Henneke G. Calcium-driven DNA synthesis by a high-fidelity DNA polymerase. Nucleic Acids Res 2017; 45:12425-12440. [PMID: 29040737 PMCID: PMC5716173 DOI: 10.1093/nar/gkx927] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/04/2017] [Indexed: 11/14/2022] Open
Abstract
Divalent metal ions, usually Mg2+, are required for both DNA synthesis and proofreading functions by DNA polymerases (DNA Pol). Although used as a non-reactive cofactor substitute for binding and crystallographic studies, Ca2+ supports DNA polymerization by only one DNA Pol, Dpo4. Here, we explore whether Ca2+-driven catalysis might apply to high-fidelity (HiFi) family B DNA Pols. The consequences of replacing Mg2+ by Ca2+ on base pairing at the polymerase active site as well as the editing of terminal nucleotides at the exonuclease active site of the archaeal Pyrococcus abyssi DNA Pol (PabPolB) are characterized and compared to other (families B, A, Y, X, D) DNA Pols. Based on primer extension assays, steady-state kinetics and ion-chased experiments, we demonstrate that Ca2+ (and other metal ions) activates DNA synthesis by PabPolB. While showing a slower rate of phosphodiester bond formation, nucleotide selectivity is improved over that of Mg2+. Further mechanistic studies show that the affinities for primer/template are higher in the presence of Ca2+ and reinforced by a correct incoming nucleotide. Conversely, no exonuclease degradation of the terminal nucleotides occurs with Ca2+. Evolutionary and mechanistic insights among DNA Pols are thus discussed.
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Affiliation(s)
- Céline Ralec
- Ifremer, Centre de Brest, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,CNRS, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,Université de Brest Occidentale, UBO, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Etienne Henry
- Ifremer, Centre de Brest, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,CNRS, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,Université de Brest Occidentale, UBO, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Mélanie Lemor
- Ifremer, Centre de Brest, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,CNRS, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,Université de Brest Occidentale, UBO, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Tom Killelea
- Ifremer, Centre de Brest, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,CNRS, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,Université de Brest Occidentale, UBO, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Ghislaine Henneke
- Ifremer, Centre de Brest, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,CNRS, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France.,Université de Brest Occidentale, UBO, LM2E, UMR 6197, Technopole Brest-Iroise, 29280 Plouzané, France
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Wang Y, Wang H, Zhang W, Shao C, Xu P, Shi CH, Shi JG, Li YM, Fu Q, Xue W, Lei YH, Gao JY, Wang JY, Gao XP, Li JQ, Yuan JL, Zhang YT. Genistein sensitizes bladder cancer cells to HCPT treatment in vitro and in vivo via ATM/NF-κB/IKK pathway-induced apoptosis. PLoS One 2013; 8:e50175. [PMID: 23365634 PMCID: PMC3554754 DOI: 10.1371/journal.pone.0050175] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 10/22/2012] [Indexed: 11/18/2022] Open
Abstract
Bladder cancer is the most common malignant urological disease in China. Hydroxycamptothecin (HCPT) is a DNA topoisomerase I inhibitor, which has been utilized in chemotherapy for bladder cancer for nearly 40 years. Previous research has demonstrated that the isoflavone, genistein, can sensitize multiple cancer cell lines to HCPT treatment, such as prostate and cervical cancer. In this study, we investigated whether genistein could sensitize bladder cancer cell lines and bladder epithelial cell BDEC cells to HCPT treatment, and investigated the possible underlying molecular mechanisms. Genistein could significantly and dose-dependently sensitize multiple bladder cancer cell lines and BDEC cells to HCPT-induced apoptosis both in vitro and in vivo. Genistein and HCPT synergistically inhibited bladder cell growth and proliferation, and induced G2/M phase cell cycle arrest and apoptosis in TCCSUP bladder cancer cell and BDEC cell. Pretreatment with genistein sensitized BDEC and bladder cancer cell lines to HCPT-induced DNA damage by the synergistic activation of ataxia telangiectasia mutated (ATM) kinase. Genistein significantly attenuated the ability of HCPT to induce activation of the anti-apoptotic NF-κB pathway both in vitro and in vivo in a bladder cancer xenograft model, and thus counteracted the anti-apoptotic effect of the NF-κB pathway. This study indicates that genistein could act as a promising non-toxic agent to improve efficacy of HCPT bladder cancer chemotherapy.
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Affiliation(s)
- Yong Wang
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - He Wang
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Wei Zhang
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chen Shao
- Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Peng Xu
- Department of Medical and Training Department, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chang Hong Shi
- Department of Experimental Animal, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jian Guo Shi
- Department of Cancer Research Institute, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yu Mei Li
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Qiang Fu
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Wei Xue
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yong Hua Lei
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jing Yu Gao
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Juan Ying Wang
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiao Ping Gao
- Department of Urology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jin Qing Li
- Department of Plastic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
- * E-mail: (JQL); (JLY); (YTZ)
| | - Jian Lin Yuan
- Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
- * E-mail: (JQL); (JLY); (YTZ)
| | - Yun Tao Zhang
- Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
- * E-mail: (JQL); (JLY); (YTZ)
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