UMR3348 – Stress génotoxiques et cancer

Publications de l’unité

Année de publication : 2017

Anissia Ait Saada, Ana Teixeira-Silva, Ismail Iraqui, Audrey Costes, Julien Hardy, Giulia Paoletti, Karine Fréon, Sarah A E Lambert (2017 May 4)

Unprotected Replication Forks Are Converted into Mitotic Sister Chromatid Bridges.

Molecular cell : 398-410.e4 : DOI : 10.1016/j.molcel.2017.04.002 En savoir plus
Résumé

Replication stress and mitotic abnormalities are key features of cancer cells. Temporarily paused forks are stabilized by the intra-S phase checkpoint and protected by the association of Rad51, which prevents Mre11-dependent resection. However, if a fork becomes dysfunctional and cannot resume, this terminally arrested fork is rescued by a converging fork to avoid unreplicated parental DNA during mitosis. Alternatively, dysfunctional forks are restarted by homologous recombination. Using fission yeast, we report that Rad52 and the DNA binding activity of Rad51, but not its strand-exchange activity, act to protect terminally arrested forks from unrestrained Exo1-nucleolytic activity. In the absence of recombination proteins, large ssDNA gaps, up to 3 kb long, occur behind terminally arrested forks, preventing efficient fork merging and leading to mitotic sister chromatid bridging. Thus, Rad52 and Rad51 prevent temporarily and terminally arrested forks from degrading and, despite the availability of converging forks, converting to anaphase bridges causing aneuploidy and cell death.

Free acces : authors.elsevier.com/a/1U~li3vVUP2C0m

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Simon Gemble, Géraldine Buhagiar-Labarchède, Rosine Onclercq-Delic, Christian Jaulin, Mounira Amor-Guéret (2017 May 2)

Cytidine deaminase deficiency impairs sister chromatid disjunction by decreasing PARP-1 activity.

Cell cycle (Georgetown, Tex.) : 1-8 : DOI : 10.1080/15384101.2017.1317413 En savoir plus
Résumé

Bloom Syndrome (BS) is a rare genetic disease characterized by high levels of chromosomal instability and an increase in cancer risk. Cytidine deaminase (CDA) expression is downregulated in BS cells, leading to an excess of cellular dC and dCTP that reduces basal PARP-1 activity, compromising optimal Chk1 activation and reducing the efficiency of downstream checkpoints. This process leads to the accumulation of unreplicated DNA during mitosis and, ultimately, ultrafine anaphase bridge (UFB) formation. BS cells also display incomplete sister chromatid disjunction when depleted of cohesin. Using a combination of fluorescence in situ hybridization and chromosome spreads, we investigated the possible role of CDA deficiency in the incomplete sister chromatid disjunction in cohesin-depleted BS cells. The decrease in basal PARP-1 activity in CDA-deficient cells compromised sister chromatid disjunction in cohesin-depleted cells, regardless of BLM expression status. The observed incomplete sister chromatid disjunction may be due to the accumulation of unreplicated DNA during mitosis in CDA-deficient cells, as reflected in the changes in centromeric DNA structure associated with the decrease in basal PARP-1 activity. Our findings reveal a new function of PARP-1 in sister chromatid disjunction during mitosis.

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Hamza Mameri, Ivan Bieche, Dider Meseure, Elisabetta Marangoni, Géraldine Buhagiar-Labarchède, Andre Nicolas, Sophie Vacher, Rosine Onclercq-Delic, Vinodh Rajapakse, Sudhir Varma, William C Reinhold, Yves Pommier, Mounira Amor-Guéret (2017 Apr 15)

Cytidine deaminase deficiency reveals new therapeutic opportunities against cancer.

Clinical cancer research : an official journal of the American Association for Cancer Research : DOI : 10.1158/1078-0432.CCR-16-0626 En savoir plus
Résumé

One of the main challenges in cancer therapy is the identification of molecular mechanisms mediating resistance or sensitivity to treatment. Cytidine deaminase (CDA) was reported to be downregulated in cells derived from patients with Bloom syndrome, a genetic disease associated with a strong predisposition to a wide range of cancers. The purpose of this study was to determine whether CDA deficiency could be associated with tumors from the general population and could constitute a predictive marker of susceptibility to anti-tumor drugs.

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Hermela Shimelis, Romy L S Mesman, Catharina Von Nicolai, Asa Ehlen, Lucia Guidugli, Charlotte Martin, Fabienne Mgr Calleja, Huong Meeks, Emily Hallberg, Jamie Hinton, Jenna Lilyquist, Chunling Hu, Cora M Aalfs, Kristiina Aittomaki, Irene L Andrulis, Hoda Anton-Culver, Volker Arndt, Matthias W Beckmann, Javier J Benitez, Natalia Bogdanova, Stig E Bojesen, Manjeet K Bolla, Anne-Lise Borresen-Dale, Hiltrud Brauch, Paul Brennan, Hermann Brenner, Annegien Broeks, Barbara Brouwers, Thomas Bruning, Barbara Burwinkel, Jenny Chang-Claude, Georgia Chenevix-Trench, Ching-Yu Cheng, Ji-Yeob Choi, J Margriet Collée, Angela Cox, Simon S Cross, Kamila Czene, Hatef Darabi, Joe Dennis, Thilo Dork, Isabel Dos Santos Silva, Alison M Dunning, Peter A Fasching, Jonine D Figueroa, Henrik Flyger, Montserrat Garcia-Closas, Graham G Giles, Gord Glendon, Pascal Guenel, Christopher A Haiman, Per Hall, Ute Hamann, Mikael Hartman, Frans B L Hogervorst, Antoinette Hollestelle, John L Hopper, Hidemi Ito, Anna Jakubowska, Daehee Kang, Veli-Matti Kosma, Vessela Kristensen, Kah-Nyin Lai, Diether Lambrechts, Loic Le Marchand, Jingmei Li, Annika Lindblom, Artitaya Lophatananon, Jan Lubinski, Eva Machackova, Arto Mannermaa, Sara Margolin, Frederik Marme, Keitaro Matsuo, Hui Miao, Kyriaki Michailidou, Roger L Milne, Kenneth Muir, Susan L Neuhausen, Heli Nevanlinna, Janet E Olson, Curtis Olswold, Jan C Oosterwijk, Ana Osorio, Paolo Peterlongo, Julian Peto, Paul D P Pharoah, Katri Pylkäs, Paolo Radice, Muhammad U Rashid, Valerie Rhenius, Anja Rudolph, Suleeporn Sangrajrang, Elinor J Sawyer, Marjanka K Schmidt, Minouk J Schoemaker, Caroline M Seynaeve, Mitul Shah, Chen-Yang Shen, Martha J Shrubsole, Xiao-Ou Shu, Susan L Slager, Melissa C Southey, Daniel O Stram, Anthony J Swerdlow, Soo Hwang Teo, Ian Tomlinson, Diana Torres, Therese Truong, Christi J van Asperen, Lizet E van der Kolk, Qin Wang, Robert Winqvist, Anna H Wu, Jyh-Cherng Yu, Wei Zheng, Ying Zheng, Jennifer Leary, Logan C Walker, Lenka Foretova, Florentia Fostira, Kathleen Claes, Liliana Varesco, Setareh Moghadasi, Douglas F Easton, Amanda B Spurdle, Peter Devilee, Harry Vrieling, Alvaro N Monteiro, David E Goldgar, Aura Carreira, Maaike P G Vreeswijk, Fergus J Couch (2017 Mar 10)

BRCA2 hypomorphic missense variants confer moderate risks of breast cancer.

Cancer research : DOI : 10.1158/0008-5472.CAN-16-2568 En savoir plus
Résumé

Breast cancer risks conferred by many germline missense variants in the BRCA1 and BRCA2 genes, often referred to as variants of uncertain significance (VUS), have not been established. In this study, associations between 19 BRCA1 and 33 BRCA2 missense substitution variants and breast cancer risk were investigated through a breast cancer case control study using genotyping data from 38 studies of predominantly European ancestry (41,890 cases and 41,607 controls) and nine studies of Asian ancestry (6,269 cases and 6,624 controls). The BRCA2 c.9104A>C, p.Tyr3035Ser (OR=2.52, p=0.04) and BRCA1 c.5096G>A, p.Arg1699Gln (OR=4.29, p=0.009) variant were associated with moderately increased risks of breast cancer among Europeans, whereas BRCA2 c.7522G>A, p.Gly2508Ser (OR=2.68, p=0.004) and c.8187G>T, p.Lys2729Asn (OR=1.4, p=0.004) were associated with moderate and low risks of breast cancer among Asians. Functional characterization of the BRCA2 variants using four quantitative assays showed reduced BRCA2 activity for p.Tyr3035Ser compared to wildtype. Overall, our results show how BRCA2 missense variants that influence protein function can confer clinically relevant, moderately increased risks of breast cancer, with potential implications for risk management guidelines in women with these specific variants.

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