DNA repair after Cadmium injury is affected by HSP27

ALVAREZ-OLMEDO D; SOTTILE M; CUELLO CARRIÓN FD; CAYADO-GUTIERREZ N; MONTT-GUEVARA MM; ARRIGO A; CIOCCA D.; NADIN S.; FANELLI M.

Congreso; VII Cell Stress Society International Congress on Stress and Health; 2015

Cell Stress Society International

Little is known about the implications of HSP27 in DNA repair. Recently, we demonstrated interactions between Mismatch Repair Proteins MLH1, and MSH2 with HSP27 and HSP70. Aim: the objective of this study was to evaluate the role of HSP27 on MLH1, MSH2, MSH6, and ERCC1 DNA repair proteins expression under cadmium (CdCl2) treatment. Methods: HeLa wt and Hsh2.2 cells (a HeLa cell line with HSP27 stably downregulated) were submitted to 0, 5, 50, 100 µM CdCl2 during 3 h and then allowed to recover in a cadmium-free medium for 21 h. Viability was carried out by MTT, DNA damage/repair was evaluated by the alkaline comet assay, and the expression of γ-H2AX, MLH1, MSH2, MSH6 and ERCC1 tested by Western blot. Results: Cell viability decreased significantly after treatments in both cells lines at 100 µM CdCl2. The DNA damage increased with the increasing cadmium doses in both cell lines. After Cd withdrawal, during the recovery period, few cells survived and they showed a slight amount of DNA damage. In HeLa wt cells, the expression of MLH1, MSH2, MSH6 and ERCC1 diminished during the recovery period after 50 and 100 µM CdCl2, in contrast the levels of these proteins increased in HeLa 2.2 cells. These changes were inversely accompanied by γ-H2AX expression, a sensitive indicator of DSBs. Conclusion: Our results show that HSP27 may affect the repair of the cadmium-induced DNA damage.