DNA damage, γH2AX and 53-BP1 status as predictive factors of response to platinum analogues-based chemotherapy

MARIA BELÉN GARCÍA; LAURA M. VARGAS ROIG; ANALIA REDONDO; JORGE IBARRA; MAYRA L. SOTTILE; REYNALDO J. FLORES LEYVA; SILVINA B. NADIN

Buenos Aires

Congreso; LXII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA; 2017

SAIC

Cisplatin (cisPt) constitute a widely used chemotherapeutic drug inthe treatment of solid tumors. Its cytotoxic mode of action is basedon the formation of DNA-interstrand and -intrastrand crosslinks withpurine bases, which interfere with normal DNA function. We havereported that alkaline comet assay may constitute a useful techniqueto study the DNA damage and repair status and to predict responseto chemotherapy in peripheral blood leukocytes (PBL) fromcancer patients. γH2AX phosphorylation has been proposed as asensitive marker of DNA double-strand breaks (DSBs). 53-BP1 isDNA damage response factor. The aim of our work was to determineDNA damage and repair rate, and to stablish their predictive valuein peripheral blood leukocytes (PBL) from cancer patients treatedwith cisPt. We isolated PBL from 5 healthy persons and 12 cancerpatients before chemotherapy. PBL were in vitro exposed to cisPt(200 µM, 1 h) or hyperthermia (42°C, 1 h), 24 h before cPt treatment(H+cisPt). The cells were harvested at: T0 (immediately after cisPt)and T24 (24 h after recovery). DNA damage/repair were evaluatedby alkaline comet assay and by immunocytochemistry using specificantibodies against γH2AX and 53-BP1. At basal conditions, healthyindividuals showed larger number of γH2AX (P˂0,05) and 53-BP1 foci (P