Figure 4. Chemotherapy resistance induced by hypoxia was reversed strongly by combining with endostar.

SW1116 cells were cultured with endostar or OXA, either alone, or in combination with OXA on 1% O₂ condition for 3 days. (A) Hypoxia survival assay, *p<0.05/***p<0.001 versus control; ⁺⁺⁺ p<0.001 versus OXA (n = 3 independent experiments). Note that endostar inhibited SW1116 cell survival under hypoxia. Hypoxia induced OXA resistance under the same condition. Endostar potently reduced OXA-induced chemotherapy resistance. (B–E) Western blots of whole cell lysates for HIF-1α, HIF-2α, CXCR4 and housekeeping protein α-tubulin expression of SW1116 cells treated with endostar, OXA or combinations under hypoxia. *p<0.05/**p<0.01/***p<0.001/versus control; ^# p<0.05 versus their respective endostar; ⁺ p<0.05 versus OXA. Noted HIF-2α has more pronounced effect on inhibiting proliferation and invasion under hypoxia, in comparison with HIF-1α (n≥3).