Figure 7.

Benznidazole induces DNA double-stranded breaks under hypoxia. MDA-MB-231 breast cancer cells (A) and cells SK-N-ER neuroblastoma (B) were incubated for 24 hours with Benznidazole (BZDZ, 100 µM), etoposide (ETOP, 1 µM) or dimethyl sulfoxide (DMSO) under aerobic (20% O₂) and anoxic (0% O₂) conditions, respectively. The nuclear foci containing the tumor suppressor p53 binding protein 1 (53BP1) were examined by immunofluorescence using antibodies specifically against 53BP1. Cells with more than 5 53BP1⁺ foci were counted in 5 random fields (200x magnification) under microscope. Total number of cells counted per experimental group: >500 cells for SK-N-ER and >200 cells for MDA-MB-231, except that total numbers of ETOP-treated cells counted were approximately 200 for each cell type.