Synthesized benzamido derivatives exert antiproliferative effects by DNA damage and ROS generation.

In this study we explored the effect and the biological action of synthesized benzamido derivatives bearing the (1S,2S)-2-phenyl-cyclopropane-1-carboxamido, 1,1'-biphen-2-carboxamido and 1,1'-biphen-4-carboxamido moieties on K562, a human leukemia cell line. Among the synthesized compounds a particular antiproliferative action was observed with the benzamido derivative bearing the 2-1,1'-biphenyl moiety with the substitution at the 5 position of the benzamido moiety with iodine. This compound showed cytotoxic effects in K562 leukemic cells at nanomolar concentrations and was, therefore, chosen as compound to explore its mode of action. Our analyses provided evidence that this benzamido derivative induced a reduction in cell number and volume with the appearance of a shrunken cytoplasm at 24h, followed by a widespread cell fragmentation at 48h. As demonstrated by flow cytometry analyses, the effect was dose- and time-dependent, causing a G2/M cell cycle arrest in the first phase of treatment (24h), followed by an apoptotic death at 48h (IC50 0.5 μM ). The elucidation of the underlying mechanism also disclosed that DNA arrest in G2/M phase of cell cycle was consequent to DNA lesions, since an increase in phospho-ATM and yH2AX, two known markers of DNA repair response system, was observed. Prolonging the time of treatment, the effects, which were observed only in leukaemic cells but not in normal bronchial epithelial cells, were accompanied by ROS production, JNK phosphorylation and induction of a caspase-dependent apoptosis.