Abstract:
Objective To determine the abnormal activation of the neurotensin (NTS)/interleukin-8 (IL-8) pathway and its effect on invasion and epithelial– mesenchymal transition (EMT) in hepatocellular carcinoma (HCC).
Methods Hepatoma cell lines Hep3BNTR1hi and HepG2NTR1- were genetically modified by gene transfection or siRNA interference to establish various NTS-sensitive HCC cell lines bearing multiple levels of NTS receptor 1 (NTR1). ELISA assay and real time RT-PCR were used to detect the difference of IL-8 protein secretion and RNA synthesis in varied NTS-sensitive Hep3B and HepG2 cell lines after exogenous NTS stimulation. The migration and invasion potentials of HCC cells were evaluated by scratch repair test and Transwell invasion assay. Western blot assay was used to detect the expression of EMT-related proteins in HCC cells with or without blocking IL-8 receptors.
Results Exogenous NTS stimulation and NTR1 overexpression enhanced the IL-8 RNA synthesis and protein secretion (P all < 0.01). Exogenous NTS stimulation and NTR1 overexpression also increased the invasion of HCC cells (P all < 0.05). Blocking IL-8 receptors reduced the wound closure rate, decreased the numbers of invasive cells, and reversed the EMT progress (P all < 0.001), including the up-regulation of E-cadherin and down-regulation of N-cadherin and β-catenin.
Conclusion In HCC cells, NTS stimulation and high expression of NTR1 induced the synthesis and secretion of IL-8, thereby promoting tumor EMT and HCC invasion.
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