HSP27 and HSP70 expression in human colorectal cancer hMLH1 deficient and hMLH1 proficient cell lines

S.B. NADIN; F. DARÍO CUELLO CARRIÓN; D.R. CIOCCA; L.M. VARGAS ROIG

Sapporo, Japón

Congreso; 4th International Congress on Stress Responses in Biology and Medicine; 2009

Cell Stress Society International

Several studies have demonstrated the variety of cellular effects produced by hyperthermia. However, the consequences of the heat shock treatment in hMLH1-deficient and hMLH-1 proficient colorectal cells have not been studied yet. hMLH1 is one of the components of the eukaryotic mismatch repair system. In this work, we have investigated the expression of HSP27 and HSP70 proteins in the human colorectal adenocarcinoma cell lines HCT116 (hMLH1-deficient, parental), HCT116+ch3 (hMLH1-proficient, complemented by chromosome 3), and HCT116+ch2 (control, complemented by chromosome 2). The cells were incubated at 41 and 42°C for 1 hour, one group was collected immediately after a heat shock (time 0, T0), and the other groups were allowed to recover for 4 and 24 hours at 37°C (time 4 and 24, T4 and T24 respectively) and then collected. The expression of HSP27 and HSP70 was analyzed by immunocytochemistry and Western blot. In addition, we studied the DNA damage using the alkaline comet assay. We observed higher expression of HSP27 and HSP70 after heat shock in HCT116+ch3 cell line in comparison with the hMLH1-deficient cell lines. We also noted high nuclear accumulation of HSP70 in HCT116+ch3 cells after the heat shock treatment at 41 and 42°C. Hyperthermia induced significant DNA damage in the three cell lines. In HCT116+ch3 cells, we observed that the heat shock treatment predominantly caused severe DNA damage (score 3: 31-60% and score 4: 61-95%), and that at 42°C it was higher than in the parental cell line at the same conditions. These preliminary results showed, for the first time, the differential expression of the HSP27 and HSP70 protein in the mismatch repair proficient and deficient cells and they constitute the initial step to study the possible implications of these proteins in the cytotoxicity induced by platin analogs.