Homologous recombination preferentially repairs heat-induced DNA double-strand breaks in mammalian cells

• Published in: International journal of hyperthermia Vol. 33; no. 3; pp. 336 - 342
• Main Authors: Takahashi, Akihisa, Mori, Eiichiro, Nakagawa, Yosuke, Kajihara, Atsuhisa, Kirita, Tadaaki, Pittman, Douglas L., Hasegawa, Masatoshi, Ohnishi, Takeo
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01.05.2017
• Subjects: DNA double-strand break; heat shock; homologous recombination; non-homologous end-joining; γH2AX; heat shock; homologous recombination; non-homologous end-joining; DNA double-strand break; γH2AX
• ISSN: 0265-6736; 1464-5157
• DOI: 10.1080/02656736.2016.1252989

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 G 2 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.