Objective To observe the influence of lysyl oxidase(LOX)downregulation via RNAi on hypoxic metastasis of human lung cancer cell 95D and stduy its molecular mechanism.Methods LOX siRNA was used to transfect 95D cell line in normoxia (19％ O2 ).After 24-hour incubation,the cells were cultured in hypoxic incubator (0.5％ O2 ) for 24h.Real-time PCR assay was applied to detect LOX mRNA and Snail mRNA expression.Levels of Src,phosphorylation of Src (P-Src Y418 ) and Snail protein were determined by Western blot assay.Transwell chamber was used to evaluate the cellular invasion potential.Results Compared with 95D cells under normoxic conditions,hypoixa treatment increased LOX mRNA expression by 14 times and invasion ability by 2.12 times respectively.Compared with siRNA control group,LOX siRNA transfection decreased LOX mRNA expression,the invasion ability of hypoxic cells,and the protein expression of P-Src Y418 and Snail by 70％ - 75％,about 30％,and about 40％ respectively (P ＜ 0.05).However,it didn't affect the expression level of Src protein or Snail mRNA ( P ＞ 0.05).Conclusions Impaired metastatic potential of hypoxic human lung cancer cell induced by LOX downregulation is associated with reduced expression level of Src activation and Snail protein.The present data provids experimental evidence for LOX as a potential target for prevention and treatment of lung cancer metastasis under hypoxia.