Inhibition of hypoxia-inducible factor-1 alpha radiosensitized MG-63 human osteosarcoma cells in vitro

• Published in: Tumori Vol. 101; no. 5; p. 578
• Main Authors: Jin, Zhu, Aixi, Yu, Baiwen, Qi, Zonghuan, Li, Xiang, Hu
• Format: Journal Article
• Language: English
• Published: United States 01.09.2015
• Subjects: Blotting, Western; Bone Neoplasms - physiopathology; Bone Neoplasms - radiotherapy; Cell Line, Tumor; Cell Survival; Disulfides - pharmacology; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1, alpha Subunit - antagonists & inhibitors; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Indole Alkaloids - pharmacology; Osteosarcoma - physiopathology; Osteosarcoma - radiotherapy; Radiation Tolerance - drug effects; Radiation-Sensitizing Agents - pharmacology; Real-Time Polymerase Chain Reaction; RNA, Small Interfering - pharmacology; Up-Regulation
• ISSN: 2038-2529
• DOI: 10.5301/tj.5000243

Hypoxia is a fundamental microenvironmental component of osteosarcoma which induces activation of the hypoxia-inducible factor-1 (HIF-1) pathway. Overexpression of HIF-1α has been linked to tumor resistance to radio- or chemotherapy. However, little is known about the effects of HIF-1α inhibition on hypoxic radioresistance of human osteosarcoma cells. Here, we investigated the effects of HIF-1α inhibition on cell survival and radiosensitivity in the MG-63 human osteosarcoma cell line. HIF-1α inhibition was achieved by small interfering RNA (siRNA) targeting of HIF-1α or via chetomin. Inhibition of the HIF-1 pathway was determined by monitoring the expression levels of HIF-1α, carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) using quantitative real-time PCR and Western blot analyses. Clonogenic assay was performed after irradiation (2-10 Gy) to investigate the effect of HIF-1α inhibition on the radiosensitivity of human osteosarcoma cells under normoxic and hypoxic conditions. Compared to the control groups, treatment with HIF-1α siRNA or chetomin significantly reduced the hypoxia-inducible radioresistance of MG-63 cells. However, siRNA and chetomin showed different effects on the radiosensitivity under normoxic conditions. Our results indicate that inhibition of HIF-1α effectively decreases hypoxia-induced transcription and radiosensitizes hypoxic MG-63 human osteosarcoma cells in vitro.