AURKA/NFκB Axis: A Key Determinant of Radioresistance in Cervical Squamous Carcinoma Cells

Abstract

Background: Cervical cancer being one of the leading gynaecological cancers, possess a major threat by its ever-increasing trend of global recurrence events. Radioresistance is one of the major challenges confronted during the treatment of cervical cancer. Radioresistance in cancer cells is manifested by increased rate of cellular proliferation, migration-invasion and cell cycle alterations. Aurora Kinase A (AURKA), a mitotic serine/threonine kinase was found to be overexpressed in cancers and is associated with development of acquired therapy resistance. The principal objective of this study revolved with exploring the mechanisms by which AURKA confers radioadaptive response in cervical cancer cells.Methods and Results: Parental cervical squamous carcinoma cell line SiHa was subjected to recurrent insult by fractionated dose of X-irradiation. Finally, a resistant subline (SiHa/RR) was isolated at 40Gy. SiHa/RR exhibited higher expression of AURKA/ pAURKA along with the signaling molecules that are favored by this kinase (HIF1α, pAkt, NFκB) vis-à-vis lower expressions of the molecules that are generally suppressed by AURKA (p53, Gadd45a). Surprisingly, inhibition of AURKA in SiHa/RR showed improved radiosensitivity by reducing the wound healing capacity, sphere forming ability and enhancing radiation induced apoptosis. Ectopic overexpression of AURKA gave rise to radioresistant phenotype in parental SiHa by stimulating nuclear translocation of NFκB. This pattern of increased nuclear localization of NFκB was also observed in resistant subline as a consequence of activation and overexpression of AURKA.Conclusion: These ndings strengthened the involvement of AURKA in radioresistance via activating NFκB mediated signaling pathway to deliver radioresistant associated adaptive complexities.