Hedgehog通路通过非配体依赖途径调控缺氧诱导的胰腺癌EMT及侵袭过程

Hedgehog signaling regulates hypoxia-induced epithelial-to-mesenchymal transition and invasion in pancreatic cancer cells in a ligand-independent manner

目的探讨Hedgehog(Hh)通路调控缺氧诱导的胰腺癌上皮间质转分化(EMT)及侵袭机制。方法PANC-1和BxPC-3细胞培养于30 mL/L氧浓度的缺氧环境,观察缺氧对胰腺癌细胞的EMT及侵袭能力的影响,并检测Hh通路中SHH、PTCH、SMO、GLI1的表达情况;运用HIF-1α小干扰RNA干扰HIF-1α的表达,观察HIF-1α对缺氧诱导的胰腺癌EMT及侵袭的影响;运用cyclopamine和GLI1 siRNA分别抑制Hh通路的SMO或GLI1表达后,观察Hh通路在缺氧诱导胰腺癌EMT中的作用。结果缺氧能够积聚HIF-1α,活化胰腺癌Hh通路,但不影响SHH的表达,并可促进胰腺癌EMT及侵袭过程;HIF-1αsiRNA能够逆转缺氧诱导的上述过程,抑制Hh的活化,但不影响SHH及PTCH的表达。cyclopamine抑制缺氧状态下SMO及GLI1的表达,GLI siRNA可抑制GLI1的表达,但不影响SMO的表达,两者均可逆转缺氧诱导的EMT及侵袭过程。结论缺氧可能是通过非配体依赖途径,上调SMO促进胰腺癌EMT及侵袭。

Objective To investigate the mechanism of Hedgehog signaling(Hh)in regulating hypoxia-induced pancreatic cancer epithelial-to-mesenchymal transition(EMT)and invasion.Methods PANC-1 and BxPC-3 cells were cultured under 3%O2 hypoxia conditions.Pancreatic cancer EMT and invasion were determined,and Hh signaling-associated genes SHH,PTCH,SMO and GLI1 were evaluated.Moreover,HIF-1αsiRNA was applied to investigate the role of HIF-1αin hypoxia-induced pancreatic cancer EMT and invasion.In addition,cyclopamine and GLI1 siRNA were used to evaluate the effect of Hh signaling on hypoxia-induced pancreatic cancer EMT and invasion.Results Hypoxia caused the accumulation of HIF-1αand activated the non-canonical Hh pathway without affecting sonic hedgehog homolog(SHH)expression.It also induced EMT process and invasion.These effects were reversible upon HIF-1αsiRNA interference with unchanged SHH and patched1(PTCH1)level.Furthermore,hypoxia-induced EMT and invasion processes were effectively inhibited by Smoothened(SMO)antagonist cyclopamine and GLI1 siRNA.In addition,cyclopamine could inhibit SMO and GLI1 expressions.GLI1 interference could not suppress the expression of SMO.Conclusion Hypoxia could trigger non-canonical Hh signaling to upregulate SMO expression to induce EMT and invasion in pancreatic cancer cells.