DEC2 knockdown in osteosarcoma cell lines (U2OS, MNNG and 143B) attenuated HIF-1α accumulation and impaired the up-regulation of HIF-1 target genes in response to hypoxia.
The purpose of the present study was to investigate the role and underlying mechanism of SUMO-specific protease 1 (SENP1)/hypoxia-inducible factor-1α (HIF-1α) feedback loop in hypoxic microenvironment of OS.
Drug resistance was not induced by HIF-1α stabilisation in normoxia by cobalt chloride nor reversed by the suppression of HIF-1α in hypoxia by shRNAi, siRNA, dominant negative HIF or inhibition with the small molecule NSC-134754, strongly suggesting that hypoxia-induced drug resistance in osteosarcoma cells is independent of HIF-1α.
We found that hBMSC-MVs promoted U2OS cell proliferation and migration under hypoxia in vitro, and that was partially associated with the PI3K/AKT and HIF-1α pathways.
We performed immunohistochemistry, immunocytochemistry, quantitative real-time PCR, Western blots and fluorescent reporter assays to evaluate the correlation between CXCR4 and HIF-1α expression in human osteosarcoma specimens or SOSP-9607 cells under normoxic and hypoxic conditions.