Pharmacological inhibition of protein kinase D2/Aurora kinase A signalling axis suppresses G2/M cell cycle progression and proliferation of epithelial ovarian cancer cells.

ABSTRACT

Epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy with poor prognosis and patient survival outcome. Protein kinase D2 (PKD2) belongs to Ca++/calmodulin-dependent serine/threonine kinase family and its aberrant expression is associated with many cellular and physiological functions associated with tumorigenesis including cell proliferation. We show that PKD2 is activated during G2/M cell cycle transition and its catalytic inactivation by small molecule inhibitor CRT0066101 or genetic knockdown caused suppression of EOC cell proliferation followed by a delay into mitotic entry. Our RNASeq analysis of PKD2-inactivated EOC cells revealed significant downregulation of genes associated with cell cycle including Aurora kinase A, a critical mitotic regulator. Mechanistically, PKD2 positively regulated Aurora kinase A stability at both transcriptional and post-translational levels by interfering with the function of Fbxw7, drove G2/M cell cycle transition and EOC cell proliferation. Moreover, pharmacological inhibition of Aurora kinase A by small molecule CD532 or its shRNA-mediated genetic knockdown suppressed EOC cell proliferation, induced G2/M cell cycle arrest and mitotic catastrophe followed by apoptosis. Taken together, our results indicated that PKD2 positively regulates Aurora kinase A during G2/M cell cycle entry and pharmacological targeting of PKD2/Aurora kinase A signalling axis could serve as a novel therapeutic intervention against a lethal pathology like EOC.