HIF1A and gastric cancer: Correspondingly, HIF1A expression was up-regulated in Drosha WT MGC-803 with ectopic miR-4646-5p (MGC-803 Drosha WT/ miR-4646-5p) cells or PHD3 silenced cells, and down-regulated in Drosha and miR-4646-5p double knockdown GC cells (MGC-803 Drosha KD/miR-4646-5p KD); and proteasome inhibitor MGC132 treatment, which inhibited ubiquitination process, partially restored the expression of HIF1A (Fig. 4F).