Homologous recombination preferentially repairs heat-induced DNA double-strand breaks in mammalian cells. (3rd April 2017)

• Record Type: Journal Article
• Authors: Takahashi, Akihisa; Mori, Eiichiro; Nakagawa, Yosuke; Kajihara, Atsuhisa; Kirita, Tadaaki; Pittman, Douglas L.; Hasegawa, Masatoshi; Ohnishi, Takeo
• Is Part Of: International journal of hyperthermia. Volume 33:Number 3(2017)
• Page Start: 336
• Page End: 342
• Publication Date: 2017-04-03
• Subjects: DNA double-strand break -- homologous recombination -- non-homologous end-joining -- γH2AX -- heat shock; Thermotherapy -- Periodicals; 615.832
• DOI: 10.1080/02656736.2016.1252989
• Languages: English
• ISSNs: 0265-6736

Abstract

Abstract: Purpose: Heat shock induces DNA double-strand breaks (DSBs), but the precise mechanism of repairing heat-induced damage is unclear. Here, we investigated the DNA repair pathways involved in cell death induced by heat shock. Materials and methods: B02, a specific inhibitor of human RAD51 (homologous recombination; HR), and NU7026, a specific inhibitor of DNA-PK (non-homologous end-joining; NHEJ), were used for survival assays of human cancer cell lines with different p53- gene status. Mouse embryonic fibroblasts (MEFs) lacking Lig4 (NHEJ) and/or Rad54 (HR) were used for survival assays and a phosphorylated histone H2AX at Ser139 (γH2AX) assay. MEFs lacking Rad51d (HR) were used for survival assays. SPD8 cells were used to measure HR frequency after heat shock. Results: Human cancer cells were more sensitive to heat shock in the presence of B02 despite their p53- gene status, and the effect of B02 on heat sensitivity was specific to the G2 phase. Rad54 -deficient MEFs were sensitive to heat shock and showed prolonged γH2AX signals following heat shock. Rad51d -deficient MEFs were also sensitive to heat shock. Moreover, heat shock-stimulated cells had increased HR. Conclusions: The HR pathway plays an important role in the survival of mammalian cells against death induced by heat shock via the repair of heat-induced DNA DSBs.