Antiproliferative in vitro effects of BI 2536-mediated PLK1 inhibition on cervical adenocarcinoma cells

Cervical adenocarcinoma is one of the most common gynecological malignancies. Despite the improvements in multimodality treatment, advanced disease is still associated with a significantly poor prognosis making the search for more effective therapeutic agents imperative. BI 2536, an unambiguous inhibitor of Polo-like kinase 1 (PLK1), has shown anticancer activity in a variety of tumor cell types. Herein, we present more evidence of the antiproliferative effects of this drug on HeLa cells. Nanomolar concentrations (10-100 nmol/l) of the drug significantly decreased cell proliferation and clonogenic capacity. Our results also demonstrate that inhibition of PLK1 promoted G2/M arrest and resulted in a dramatic increase in the mitotic index after 24 h of treatment. Apoptosis onset was evinced by the accumulation of a sub-G1 population as well as by a significant increase in caspase-3 activity at longer periods of exposure. Taken together, our results reinforce the prospect of directing against PLK1 as a potential therapeutic target to be evaluated in different preclinical models for cervical carcinoma.