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Falchi F, Giacomini E, Masini T, Boutard N, Di Ianni L, Manerba M, Farabegoli F, Rossini L, Robertson J, Minucci S, Pallavicini I, Di Stefano G, Roberti M, Pellicciari R, Cavalli A. Synthetic Lethality Triggered by Combining Olaparib with BRCA2-Rad51 Disruptors. ACS Chem Biol 2017; 12:2491-2497. [PMID: 28841282 DOI: 10.1021/acschembio.7b00707] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In BRCA2-defective cells, poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitors can trigger synthetic lethality, as two independent DNA-repairing mechanisms are simultaneously impaired. Here, we have pharmacologically induced synthetic lethality, which was triggered by combining two different small organic molecules. When administered with a BRCA2-Rad51 disruptor in nonmutant cells, Olaparib showed anticancer activity comparable to that shown when administered alone in BRCA2-defective cells. This strategy could represent an innovative approach to anticancer drug discovery and could be extended to other synthetic lethality pathways.
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Affiliation(s)
- Federico Falchi
- CompuNet, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Elisa Giacomini
- CompuNet, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Tiziana Masini
- CompuNet, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Nicolas Boutard
- CompuNet, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
| | - Lorenza Di Ianni
- Department
of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Via S. Giacomo 14, I-40126 Bologna, Italy
| | - Marcella Manerba
- Department
of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Via S. Giacomo 14, I-40126 Bologna, Italy
| | - Fulvia Farabegoli
- Department
of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro
6, I-40126 Bologna, Italy
| | - Lara Rossini
- TES Pharma S.r.l., Via Palmiro Togliatti 22bis, I-06073 Loc. Terrioli, Corciano, Perugia, Italy
| | - Janet Robertson
- TES Pharma S.r.l., Via Palmiro Togliatti 22bis, I-06073 Loc. Terrioli, Corciano, Perugia, Italy
| | - Saverio Minucci
- Department
of Experimental Oncology at the European Institute of Oncology, IFOM-IEO Campus, Via Adamello 16, I-20100 Milan, Italy
- Department
of Biosciences, University of Milan, Via Celoria 26, I-20100 Milan, Italy
| | - Isabella Pallavicini
- Department
of Experimental Oncology at the European Institute of Oncology, IFOM-IEO Campus, Via Adamello 16, I-20100 Milan, Italy
| | - Giuseppina Di Stefano
- Department
of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Via S. Giacomo 14, I-40126 Bologna, Italy
| | - Marinella Roberti
- Department
of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro
6, I-40126 Bologna, Italy
| | - Roberto Pellicciari
- TES Pharma S.r.l., Via Palmiro Togliatti 22bis, I-06073 Loc. Terrioli, Corciano, Perugia, Italy
| | - Andrea Cavalli
- CompuNet, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova, Italy
- Department
of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro
6, I-40126 Bologna, Italy
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Magwood AC, Malysewich MJ, Cealic I, Mundia MM, Knapp J, Baker MD. Endogenous levels of Rad51 and Brca2 are required for homologous recombination and regulated by homeostatic re-balancing. DNA Repair (Amst) 2013; 12:1122-33. [PMID: 24210700 DOI: 10.1016/j.dnarep.2013.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 10/15/2013] [Indexed: 12/17/2022]
Abstract
Stable expression of Rad51 siRNA was used to generate mouse hybridoma cell lines in which endogenous Rad51 levels were depleted by as much as 60%. Stable Rad51 knockdowns feature reduced homologous recombination responses. The relative ease with which stable Rad51 knockdowns were recovered was surprising, given the embryonic lethality of Rad51 ablation. Interestingly, Rad51-depleted hybridoma cell lines are characterized by reduced levels of p53 protein. Completely unexpected, was the finding that Rad51-depleted hybridoma cell lines are also reduced for the breast cancer susceptibility 2 (Brca2) protein. Additionally, hybridoma cell lines that are siRNA depleted for mouse Brca2 show a corresponding reduction in Rad51 and p53 proteins. Furthermore, cellular levels of Rad51, Brca2 and p53 can be elevated in these cell lines by ectopic expression of wild-type human Rad51 and wild-type human BRCA2. In marked contrast, hybridoma cell lines that are siRNA depleted for mouse p53 feature relatively normal Rad51 and Brca2 levels. These results suggest that cellular levels of Brca2 and Rad51 are mutually dependent on each other, and that low levels of these proteins provide selective pressure for reduction of p53, which permits cell growth.
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Affiliation(s)
- Alissa C Magwood
- Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Abstract
Radiation therapy methods have evolved remarkably in recent years which have resulted in more effective local tumor control with negligible toxicity of surrounding normal tissues. However, local recurrence and distant metastasis often occur following radiation therapy mostly due to the development of radioresistance through the deregulation of the cell cycle, apoptosis, and inhibition of DNA damage repair mechanisms. Over the last decade, extensive progress in radiotherapy and gene therapy combinatorial approaches has been achieved to overcome resistance of tumor cells to radiation. In this review, we summarize the results from experimental cancer therapy studies on the combination of radiation therapy and gene therapy.
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Common fragile sites in colon cancer cell lines: role of mismatch repair, RAD51 and poly(ADP-ribose) polymerase-1. Mutat Res 2011; 712:40-8. [PMID: 21570414 DOI: 10.1016/j.mrfmmm.2011.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 04/01/2011] [Accepted: 04/27/2011] [Indexed: 11/21/2022]
Abstract
Common fragile sites (CFS) are specific chromosomal areas prone to form gaps and breaks when cells are exposed to stresses that affect DNA synthesis, such as exposure to aphidicolin (APC), an inhibitor of DNA polymerases. The APC-induced DNA damage is repaired primarily by homologous recombination (HR), and RAD51, one of the key players in HR, participates to CFS stability. Since another DNA repair pathway, the mismatch repair (MMR), is known to control HR, we examined the influence of both the MMR and HR DNA repair pathways on the extent of chromosomal damage and distribution of CFS provoked by APC and/or by RAD51 silencing in MMR-deficient and -proficient colon cancer cell lines (i.e., HCT-15 and HCT-15 transfected with hMSH6, or HCT-116 and HCT-116/3+6, in which a part of a chromosome 3 containing the wild-type hMLH1 allele was inserted). Here, we show that MMR-deficient cells are more sensitive to APC-induced chromosomal damage particularly at the CFS as compared to MMR-proficient cells, indicating an involvement of MMR in the control of CFS stability. The most expressed CFS is FRA16D in 16q23, an area containing the tumour suppressor gene WWOX often mutated in colon cancer. We also show that silencing of RAD51 provokes a higher number of breaks in MMR-proficient cells with respect to their MMR-deficient counterparts, likely as a consequence of the combined inhibitory effects of RAD51 silencing on HR and MMR-mediated suppression of HR. The RAD51 silencing causes a broader distribution of breaks at CFS than that observed with APC. Treatment with APC of RAD51-silenced cells further increases DNA breaks in MMR-proficient cells. The RNAi-mediated silencing of PARP-1 does not cause chromosomal breaks or affect the expression/distribution of CFS induced by APC. Our results indicate that MMR modulates colon cancer sensitivity to chromosomal breaks and CFS induced by APC and RAD51 silencing.
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Kobayashi J, Okui M, Asaithamby A, Burma S, Chen BPC, Tanimoto K, Matsuura S, Komatsu K, Chen DJ. WRN participates in translesion synthesis pathway through interaction with NBS1. Mech Ageing Dev 2010; 131:436-44. [PMID: 20600238 DOI: 10.1016/j.mad.2010.06.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 06/06/2010] [Accepted: 06/09/2010] [Indexed: 01/23/2023]
Abstract
Werner syndrome (WS), caused by mutation of the WRN gene, is an autosomal recessive disorder associated with premature aging and predisposition to cancer. WRN belongs to the RecQ DNA helicase family, members of which play a role in maintaining genomic stability. Here, we demonstrate that WRN rapidly forms discrete nuclear foci in an NBS1-dependent manner following DNA damage. NBS1 physically interacts with WRN through its FHA domain, which interaction is important for the phosphorylation of WRN. WRN subsequently forms DNA damage-dependent foci during the S phase, but not in the G1 phase. WS cells exhibit an increase in spontaneous focus formation of poleta and Rad18, which are important for translesion synthesis (TLS). WRN also interacts with PCNA in the absence of DNA damage, but DNA damage induces the dissociation of PCNA from WRN, leading to the ubiquitination of PCNA, which is essential for TLS. This dissociation correlates with ATM/NBS1-dependent degradation of WRN. Moreover, WS cells show constitutive ubiquitination of PCNA and interaction between PCNA and Rad18 E3 ligase in the absence of DNA damage. Taken together, these results indicate that WRN participates in the TLS pathway to prevent genomic instability in an ATM/NBS1-dependent manner.
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Affiliation(s)
- Junya Kobayashi
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan.
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