Effcet of silencing HIF-1α by siRNA on expression of toll-like receptor 4 in pancreatic cancer cells under hypoxic conditions

Abstract

Objective To investigate the expression of HIF-1 α and toll-like receptor 4 (TLR4) in human pancreatic cancer cell line panc-l under hypoxia.To observe the effect of HIF-1α in the regulation of TLR4 expression in pancreatic cancer cells under hypoxic conditions.Methods Cells were placed in airtight chamber or treated with CoCl2 to mimic tumor hypoxic micro environment.mRNA and protein levels of HIF-lα and TLR4 were detected by reverse transcription-polymerase chain reaction(RT-PCR) and flow cytometric analysis.By RNA interference( RNAi ) originated from small interference RNA (siRNA) to use siRNA was transfected into panc-1 cells.Western blot was used to detect gene scilencing effect on HIF-1α.RT-PCR and flow cytometric analysis was used to observe the change of TLR4 gene expression after HIF-1α gene silence.Results Under hypoxia,both mRNA and protein levels of TLR4 were up-regulated.The siRNA targeting HIF-1α gene down-regulated HIF-1α gene in panc-l cells efficiently,and TLR4 gene was down-regulated as well.Conclusions Hypoxia can increase protein level of TLR4 in pancreatic cancer cells.TLR4 signaling pathway together with HIF-1α may promote development of the pancreatic cancer. Key words: Pancreatic neoplasms; Toll-like receptor 4; Hypoxia-inducible factor 1, alpha subunit