Abstract
Cervical cancer is one of the most common female malignancies around the world, and radiation resistance is a major obstacle to cancer therapy. Previously, overexpression of the long noncoding ribonucleic acid (RNA) (lncRNA) HOX transcript antisense RNA (HOTAIR) has been found to be associated with the invasion and metastasis capacities of several epithelial cancers, including cervical cancer. To gain insights into the molecular mechanisms of HOTAIR in cervical cancer resistance to radiotherapy, we investigated cellular autophagy and epithelial-to-mesenchymal transition (EMT) in radioresistant human cervical cancer HeLa cells when HOTAIR was suppressed. HOTAIR levels were quantified in cancerous and noncancerous cervical tissues obtained from 108 patients with cervical cancer. Next, we inhibited HOTAIR by RNA interference and activated the Wnt signaling pathway by LiCl in radioresistant HeLa cells to investigate the regulatory mechanisms for the HOTAIR mediating Wnt signaling pathway. We determined that the upregulated HOTAIR may contribute to cervical cancer progression. We found that the short interfering ribonucleic acid (siRNA)-mediated knockdown of HOTAIR disturbed the Wnt signaling pathway, reduced autophagy, inhibited EMT, decreased cell proliferation, and induced apoptosis in radioresistant HeLa cells. It is worthy to note that the combination treatment of siRNA-HOTAIR and LiCl demonstrated that the activation of the Wnt signaling pathway is responsible for the beneficial effect of HOTAIR knockdown in enhancing sensitivity to radiotherapy in radioresistant HeLa cells. Together, our results revealed an important role of HOTAIR in regulating cervical cancer resistance to radiotherapy. Functional suppression of HOTAIR could enhance sensitivity to radiotherapy by reduction of autophagy and reversal of EMT through the suppression of the Wnt signaling pathway.