Cell culture
Human umbilical vein endothelial cells (HUVECs) were
cultured as previously described [10, 11]. Tumor cell lines
including A549, H1299 and HCC827 were obtained from
ATCC and cultured in DMEM supplemented with 10 % fetal
bovine serum (FBS) (Invitrogen) [12]. Tumor–endothelial coculture
experiments were performed in six-well plates with
8-micron transwell inserts (BD Biosciences). Tumor cells
were seeded in the top inserts with EC monolayers co-cultured
in the bottom wells [13, 14]. MicroRNA mimics, inhibitors or
mouse full-length HIF-1a expressing plasmid were transfected
with Lipofectamine 2000 (Invitrogen). MicroRNA
mimics and inhibitors were synthesized and obtained from
GenePharma. Expression of miR-494 and HIF-1a after
transfection were shown in Supplemental Fig. 1D–E.