This study aimed to investigate the effects of knocking down hypoxia-inducible factor-1α (HIF-1α) through RNA interference on hypoxia-induced increases in drug resistance in A549/CDDP cells, and to study the underlying mechanisms. A small interfering RNA (siRNA) eukaryotic expression vector targeting HIF-1α was constructed and transfected into A549/CDDP cells treated with hypoxia. The mRNA and protein levels of HIF-1α, multidrug resistance-1 (MDR1), and multidrug resistance-associated protein (MRP) were determined by reverse transcription p...