Objective To study the mechanism of hypoxia-induced IL-11 secretion in osteosarcoma cell line U2OS.Methods U2OS cells were cultured （1%O2） in vitro under hypoxia condition with the hypoxia-inducible factor-1α （HIF-1α） inhibitor or different signal pathway inhibitors preincubated in advance.The protein level of HIF-1α was detected by Western blot

and the mRNA level of IL-11 was detected by RT-PCR

and the protein level of IL-11 was detected by enzymelinked immunosorbent assay (ELISA). Results Under hypoxia condition

the expression of HIF-1α was significantly increased

and the mRNA and protein levels of IL11 were also significantly increased (P<0.05)

which is in a time dependent manner.In addition

the hypoxiainduced HIF-1α expression and the mRNA and protein levels of IL-11 were significantly inhibited when cells were incubated with the HIF-1α inhibitor (P＜0.05).When cells were pretreated with JNK signal inhibitor

the expression and secretion of IL-11 were significantly inhibited (P＜0.05) while the expression of HIF-1α was not altered (P＞0.05). Conclusion Hypoxia could induce the secretion of IL-11 by U2OS cells via HIF-1α-JNK signal pathway

which may be involved in the development of osteosarcoma.