HIF1α/HIF2α-miR210-3p network promotes glioblastoma proliferation and tumorigenesis through EGFR-PI3K/AKT signaling pathway with a positive feedback

HIF1α promotes glioblastoma cell proliferation and tumorigenesis under hypoxia conditions, leading to poor prognosis; however, none of the targeted therapies of HIF1α for glioblastoma is success nowadays. Therefore, we focused to look for the reason and wondered whether HIF2α contributed GBM growth. We did gene-chip and found that HIF2α contributed to the malignant progression of glioblastoma while blocking of HIF1α. Furthermore, our results revealed knock-out of HIF1α and HIF2α simultaneously improved the chemo-sensitization significantly. Moreover, miR-210-3p induced HIF1α expression but inhibited HIF2α, which meant the existence of regulation of cycle between HIF1α/HIF2α and miR-210-3p. Traditional studies have proved EGF as an upstream gene regulator of HIF1α in hypoxia conditions through EGFR-PI3K/AKT-mTOR signaling pathway. However, in this study, besides the signaling pathways mentioned above, we found the upstream regulators HIF1α and HIF2α also promoted EGF with the binding regions AGGCGTGG and GGGCGTGG. Briefly, in hypoxia microenvironment HIF1α/HIF2α-miR210-3p network promotes malignant progression of glioblastoma through EGFR-PI3K/AKT-mTOR signaling pathway with a positive feedback. The control cells without HIF1α and HIF2α interference, HIF1α-ko, HIF2α-ko and HIF1α/HIF2α knock-out simultaneously cells were cultured under hypoxia conditions for 24h and then the cells were collected. The cells were then sent to undergo miRNA-Seq.