Over-Expression of Nerve Growth Factor-β in Human Cholangiocarcinoma QBC939 Cells Promote Tumor Progression

AIMS It has been shown that nerve growth factor-β (NGF-β) promoted the initiation and progression of many tumors, and we have previously demonstrated that the expression of NGF-β was associated with tumor stage, nerve infiltration and lymph node metastasis in human hilar cholangiocarcinoma. However, whether NGF-β promotes tumor progression in human cholangiocarcinoma requires further investigation. Therefore, we aimed to determine the effects of NGF-β on the progression of human cholangiocarcinoma. METHODS Human cholangiocarcinoma QBC939 stable cell lines with over-expressed or silenced NGF-β genes were generated with pEGFP-N1-NGF-β and pGPU6/GFP/Neo-NGF-β-shRNA recombinant plasmids. Cell proliferation assay, colony formation assay, cell cycle analysis, apoptosis assay and tumorigenicity assay were performed to evaluate the role of NGF-β in the progression of human cholangiocarcinoma. In addition, human lymphatic endothelial cells were co-cultured with QBC939 culture supernatants, and the cell proliferation and migration abilities of the lymphatic endothelial cells were evaluated. RESULTS Forced expression of NGF-β in QBC939 cell lines promoted proliferation, colony formation and tumorigenicity in these cells and inhibited the apoptosis. However, down-regulation of NGF-β inhibited proliferation, colony formation and tumorigenicity, and increased the apoptotic rate of QBC939 cells. In addition, the NGF-β gain-of-function induced a high expression of vascular endothelial growth factor C and enhanced the proliferation and migration of lymphatic endothelial cells, while NGF-β loss-of-function showed opposite effects. CONCLUSIONS We concluded that NGF-β promoted tumor progression in human cholangiocarcinoma QBC939 cells. Our results provided a new concept to understand the role of NGF-β in cholangiocarcinoma progression, and might provide important information for the development of new targeted therapies in human cholangiocarcinoma.