Effects of temozolomide (TMZ) on the expression and interaction of heat shock proteins (HSPs) and DNA repair proteins in human malignant glioma cells

GISELA N. CASTRO; NIUBYS CAYADO-GUTIÉRREZ; FCM ZOPPINO; MARIEL A. FANELLI; FD CUELLO-CARRIÓN; MAYRA L. SOTTILE; NADIN SB; DANIEL R. CIOCCA

CELL STRESS & CHAPERONES.

SPRINGER

Lugar: Berlin; Año: 2015 vol. 20 p. 253 - 265

1355-8145

molecular markers were associated with high-grade astrocitomas suggesting that these markers are related with the disease outcome and the response to treatments. With the aim to better understand of resistance/susceptibility processes associated to TMZ treatment, we have studied the biological effects of TMZ administration in human glioma cell lines evaluating the expression levels of proteins related to treatment resistance and DNA repair. Methods: Three human glioma cell lines: Gli36, U87 and DBTRG were treated with TMZ. The biological effects of drug were evaluated through different biological assays (viability, survival, apoptosis by TUNEL, senescence and comet). The expression of HSPA, HSPB1, MGMT, MLH1 and MSH2 were evaluated by immunocytochemical, immunofluorescence and western blot. Immunoprecipitation technique was used to analyze the protein interaction. Results: The cell lines exhibited different viability, apoptosis and senescence after TMZ administration. Gli36 cells showed very low recovery capacity following TMZ administration and this was related to high DNA damage levels, however, the cells maintained their viability. In these cells MGMT, MSH2, HSPA and HSPB1 levels increased significantly after TMZ administration. MSH2 and HSPB1 proteins appeared colocalized in Gli36 cells by confocal microscopy. This colocalization increased after TMZ treatment. In immunoprecipitation analysis MSH2 and HSPB1 appeared interacting. In contrast, HSPB1 did not interact with MGMT. Conclusion: This is the first report on the interaction of HSPB1 with a protein of the MMR system following TMZ administration in glioma cells. Key Words: temozolomide, glioma, heat shock protein, mismatch repair, MGMT Nadin SB and Ciocca DR equally contributed to this work.