Lopes Jaime L, Chaudhry Sophia, Lopes Guilherme S, Levin Nancy K, Tainsky Michael A
Center for Molecular Medicine and Genetics and Department of Oncology, Wayne State University School of Medicine, 421 E. Canfield Street, Suite 3126, Detroit, MI 48201, USA; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
Center for Molecular Medicine and Genetics and Department of Oncology, Wayne State University School of Medicine, 421 E. Canfield Street, Suite 3126, Detroit, MI 48201, USA.
Cancer Genet. 2019 Jun;235-236:57-64. doi: 10.1016/j.cancergen.2019.04.061. Epub 2019 May 9.
Although 25% of ovarian cancer cases are due to inherited factors, most of the genetic risk remains unexplained. We previously identified candidate genes through germline whole exome sequencing of BRCA1/BRCA2 negative ovarian cancer patients with familial risk. Here, we performed functional assessment to determine whether they act as BRCA-like tumor suppressors. Seven candidate risk genes were targeted by siRNA for mRNA depletion followed by functional assays for clonogenic survival, cytotoxicity to DNA damaging agents, and involvement in homologous recombination repair. BRCA1 and BRCA1 were targeted as standards for loss of function outcome. Knockdown of various candidate genes led to tumor suppressor phenotypes also observed in BRCA1/BRCA2 deficient cells. Deficiency of CHEK1, FANCM and TP53I3 led to reduced homologous recombination repair efficiency. Knockdown of RAD1, CHEK1 or FANCM led to a decrease in cellular viability and cells deficient in CHEK1, RAD1 or TP53I3 displayed increased sensitivity to cisplatin. Functional studies of candidate genes identified by whole exome sequencing complements bioinformatics techniques and aid the implication of novel risk loci. The results of this study suggest that genes found mutated in hereditary ovarian cancer, FANCM, RAD1, CHEK1 and TP53I3, act as BRCA-like tumor suppressors.
尽管25%的卵巢癌病例归因于遗传因素，但大多数遗传风险仍无法解释。我们之前通过对有家族风险的BRCA1/BRCA2阴性卵巢癌患者进行种系全外显子测序，确定了候选基因。在此，我们进行了功能评估，以确定它们是否作为类BRCA肿瘤抑制因子发挥作用。通过小干扰RNA（siRNA）靶向七个候选风险基因以耗尽mRNA，随后进行克隆形成存活、对DNA损伤剂的细胞毒性以及参与同源重组修复的功能测定。将BRCA1和BRCA2作为功能丧失结果的标准进行靶向。敲低各种候选基因会导致在BRCA1/BRCA2缺陷细胞中也观察到的肿瘤抑制表型。CHEK1、FANCM和TP53I3的缺陷导致同源重组修复效率降低。敲低RAD1、CHEK1或FANCM会导致细胞活力下降，而CHEK1、RAD1或TP53I3缺陷的细胞对顺铂的敏感性增加。通过全外显子测序鉴定的候选基因的功能研究补充了生物信息学技术，并有助于揭示新的风险位点。本研究结果表明，在遗传性卵巢癌中发现的FANCM、RAD1、CHEK1和TP53I3基因作为类BRCA肿瘤抑制因子发挥作用。
