HSP27 (HSPB1) DOWNREGULATION THROUGH ATR/CHK1 PATHWAY INCREASES CISPLATIN SENSITIVITY IN HUMAN COLON CANCER CELLS

CAYADO-GUTIERREZ, NIUBYS; REDONDO, ANALIA L; CUELLO-CARRIÓN DARIO; LOSSINO, ANTONELLA; FANELLI, MARIEL; VARGAS ROIG, LAURA M; NADIN, SILVINA B

Simposio; Second Virtual International Symposium on Cellular and Organismal Stress Responses; 2022

HSPB1 has been related to cisplatin (cPt) resistance. We reported that HSPB1 interacts with DNA mismatch repair (MMR) colorectal cancer cells. This study aims to investigate HSPB1 and ATR/CHK1 pathway relationship in cPt-exposed HCT116+ch2 (deficient, MMR-) and HCT116+ch3 (proficient, MMR+) cells. HSPB1 was downregulated with OGX427 and ATR inhibition by VE-821 (VE). Cells were incubated with 10 μM cPt, 24 h and collected at 0(T0), 3(T3), 9(T9) and 24(T24)h post-treatments. HSP27 nuclear colocalization with CHK1 was demonstrated in cPt-treated MMR-/+ cells. Combined therapy with cPt+OGX427 or cPt+VE reduced cell viability, particularly after cPt+VE in MMR- cells (p