MODULATION OF Β-CATENIN BY HSP27 IN CANCER CELLS: EFFECTS OF CADMIUM ADMINISTRATION

ALVAREZ OLMEDO D; SHORTREDE J; CAYADO-GUTIERREZ N; CIOCCA DR; FANELLI MA

Montevideo

Conferencia; First Conference South American Chapter Cell Stress Society International; 2014

Cell Stress Society International

Introduction: We have described interactions between β-catenin and Hsp27 in HeLa and MCF-7 cells, while in MDA-MB-231 cells there was an association between β-catenin and caveolin-1. These interactions were modified by Cd treatment (HeLa and MCF-7 cells were more sensitive to the toxic). Objectives: To evaluate the effects of Cd treatment on b-catenin and Hsp27 at mRNA and protein level in cancer cell lines. To study b-catenin modulation by Hsp27 in HeLa cells. Methodology: HeLa, MDA-MB-231 and MCF-7 cells were exposed during 3-24 h to CdCl2 (0, 1, 5, 10, 25, 50, 100 μM). mRNA and protein expression were evaluated by qPCR and WB. Localization of b-catenin and Hsp27 were studied by IF. Hsp27 down regulation was carried out using shRNA. Results: Under basal conditions β-catenin mRNA levels were similar in HeLa and MCF-7. Following Cd treatment we observed an increment of β-catenin at 5 μM Cd p (*) only in HeLa cells. MDA-MB-231 showed an increment of Hsp27 mRNA at 50 and 100 μM Cd p (**), while in HeLa Hsp27 increased at 50 μM Cd p (*). In Hela, the dynamic of protein expression showed a decrease in Hsp27 levels at 50 and 100 μM Cd p (*) and (**) after 24 h of treatment; at the same time, β-catenin was phosphorylated at (Thr41/Ser45) with 100 uM Cd. IF showed changes in β-catenin distribution, an increase in Hps27 granular formation in the nucleous with 3-24 h of Cd treatment. Under Hsp27 down regulation we found a decrease in β-catenin levels in HeLa and MCF-7 cells. Stable transfection of HeLa cells showed a correlation between Hsp27 and β-catenin expression. Cells with 50% of the Hsp27 respond to Cd treatment diminishing its β-catenin levels (Cd 100 p ***), but when a 90% of total Hsp27 was down regulated, the levels of β-catenin were very low and could not be modify by Cd treatment. Conclusions: Cd treatment induces differences in mRNA level at 3 h. Nevertheless protein changes were showed only after 5 h in HeLa cells. Regulation of β-catenin is modulated by Hsp27.