Protein extraction and immunoblotting

Cells were lysed in IP Lysis/Wash buffer (Thermo Fisher Scientific) supplemented with 5% (vol/vol) Protease Mixture Inhibitor (MilliporeSigma) and 1 mM phenylmethanesulfonyl (MilliporeSigma). After two homogenization cycles (7 s) with an ultrasonic cell disruptor (Microson; Misonix), total cell lysates were centrifuged at 18,000g for 10 minutes. The supernatant containing proteins was collected and the protein concentration was determined by Pierce BCA Protein Assay Kit (Thermo Fisher Scientific). Immunoblotting analysis was carried out as previously described (8 (link)). Antibodies against Actin (MilliporeSigma, A2066; dilution 1:4000), DOT1L (Cell Signaling, 77087; dilution 1:1000), HIF1A (Abcam, ab82832; dilution 1:1000), total H3 (Abcam, ab1791; dilution 1:10,000), and H3K79me2 (Abcam, ab3594; dilution 1:1000) were used following the manufacturer’s instructions. The blotting signals were detected using the SuperSignalWest Femto Maximum Sensitivity Substrate system (Thermo Fisher Scientific).