Kinetics of tumorigenic vascular endothelial growth factor signalling and its significance in human hepatocellular carcinoma cells

Ras-VEGF-concerned angiogenesis is correlated with oncogene maintenance, tumorigenesis, metastasis and resistance to anti-cancer therapies; however, this association is not clearly elucidated by serum VEGF, due to VEGF signalling in blood cells themselves. The present study aimed to elucidate tumorigenic VEGF signalling in eight human HCC cell types and reveal the kinetics of tumorigenic VEGF signalling in three time intervals, thereby discovering the relationships of VEGF-concerned angiogenesis signalling with the extent of the human HCC cell growth, metastasis and resistance to anti-cancer drugs, by using the poorly metastatic SMMC7721, 7402/D+ (doxorubicin-resistance) and 7402/D- (doxorubicin-withdrawal), the highly metastatic MHCC1 non-transfected human HCC cell lines, and the highly metastatic A3-1, F8, F11 and E3 human HCC cell lines transfected with expressing green fluorescence protein into the phenotype of MHCC1 cells, and quantitative 'sandwich' ELISA analyses. The unique results indicated attributes and objective laws as follows. Human HCC cell growth requires time-dependent tumorigenic VEGF signalling; levels of VEGF signalling are positively correlated with each cell phenotype itself; and levels of VEGF signalling are inversely correlated with the possibility of metastasis and drug resistance. The contrast data first reveal important clues for exploring dual metastatic mechanisms via tumor cell-generated non-endothelium vasculogenesis and VEGF-endothelium-attached angiogenesis that may be essential for developing novel strategies aimed at VEGF-concerned signal networks in ischemic/metastatic diseases and transgenic models.