HIF1A and non-small cell lung carcinoma: We therefore analyzed the effect of KLF5 knockdown on the expression of HIF-1α in NSCLC cells under hypoxia by western blot and the results implied that hypoxia exposure enhanced the protein level of HIF-1α in A549 (Fig. 3a) and H1299 (Fig. 3c) cells, while KLF5 knockdown suppressed hypoxia-induced increase of HIF-1α expression.