Overexpression of HOTAIR leads to radioresistance of human cervical cancer via promoting HIF-1α expression

Background HOTAIR was known to enhance radioresistance in several cancers. However, the function of HOTAIR on radioresistance involving the regulation of HIF-1α in cervical cancer has not been reported. Methods BALB/c nude mice were injected subcutaneously with HeLa cells and irradiated by X-ray. The tumor volume was measured and the expression of HOTAIR in tumors was detected by quantitative real-time PCR. Western blot was performed to detect the protein level of HIF-1α. MTT (3-(4,5-Dimethylthiazol-2-yl) 22,5-diphenyltetrazolium bromide) assay and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was used to examine the cell viability and cell apoptosis of HeLa cells and C33A cells exposed to radiation. Results Radiotherapy inhibited the tumor growth in mice bearing HeLa cells. Radiotherapy reduced the expression of HOTAIR and HIF-1α in tumor tissues and HeLa cells or C33A cells. HOTAIR overexpression abrogated the effect of radiation on the cell viability and cell apoptosis of HeLa and C33A cells. HOTAIR also upregulated the expression of HIF-1α in HeLa and C33A cell exposed to radiation. HIF-1α knockdown reversed increasing cell viability and reducing apoptosis of HeLa and C33A cell induced by HOTAIR overexpression. HOTAIR overexpression promoted tumor growth in mice bearing HeLa and exposed to radiation. Conclusion Radiotherapy might inhibit cervical cancer cell growth through HOTAIR /HIF-1α pathway.