Inducing Effects Of Hepatocyte Growth Factor On The Invasion And Expression Of Vascular Endothelial Growth Factor In Human Colorectal Carcinoma Cells Through MEK And PI3K Signaling Pathways

Objective:1. To evaluate the clinical pathological effects of serum VEGF and HGFin patients with Colorectal Carcinoma.2. To identify whether HGF can promote adhesion, migration andinvasion of human colorectal carcinoma cell lines in vitro.3. To investigate the transcription of VEGF mRNA and expression ofVEGF protein in human colorectal carcinoma cell lines after treatedwith extraneous HGF in vitro.4. To investigate the role of c-Met,MEK/ERK1/2 and PI3K/AKT signaltransduction pathways in the effect exerted by HGF on adhesion,migration and invasion abilities and VEGF expression of humancolorectal carcinoma cell lines.Methods:1. The serum levels of hepatocyte growth factor and vascular endothelialgrowth factor in patients with colorectal carcinoma and controlsubjects were measured by ELISA.2. The cell adhesion ability was tested by MTT assay, cell migrationability was identified by Transwell plate and invasion ability wasobserved by a Matrix gel coated Transwell plate.3. The mRNA level of vascular endothelial growth factor was analyzedby reverse-transcription PCR.4. Western blot assay was performed to assess c-Met and many other proteins involved in the MEK and PI3K signaling pathwayscontributing to cell invasion and expression of VEGF in colorectalcarcinoma cells.Results:1. The serum levels of HGF and VEGF in patients with colorectalcarcinoma increased nearly 2.8-fold and 2.5-fold than those of controlsubjects, respectively; In addition, the levels of serum HGF and VEGFcorrelated with tumor stage and lymph node metastasis respectively;the level of serum VEGF correlated positively with the serum level ofHGF in patients with colorectal carcinoma.2. Human colorectal carcinoma cells adhesion ratio, migration ratio andinvasion ratio were all increased rapidly after treated with extrinsicsource 40ng HGF. A significant decreased ratio of cell adhesion,migration and invasion could be detected after Herbimycin A, UO 126and LY294002 were added to the culture media respectively.3. A small quantity of VEGF mRNA and protein were detected incolorectal carcinoma cell lines by reverse-transcription PCR andWestern blot. In vitro, extraneous hepatocyte growth factor markedlyupregulated protein and mRNA levels of vascular endothelial growthfactor in colorectal carcinoma cells.4. Hepatocyte growth factor induced phosphorylation of c-Met, ERK1/2and AKT in a dose-dependent manner respectively. Specific inhibitorson MEK and PI3K inhibited the hepatocyte growth factor-inducingexpression of vascular endothelial growth factor in colorectalcarcinoma cells.Conclusions:1. The serum levels of HGF and VEGF in patients with colorectalcarcinoma increased; moreover, the level of serum HGF probably correlated with tumor local invasion and metastasis; the level ofserum VEGF probably correlated positively with the serum level ofHGF.2. HGF can significantly promote the adhesion, migration and invasionabilities of human colorectal carcinoma cell lines.3. HGF can increase VEGF mRNA transcription and VEGF proteinexpression in human colorectal carcinoma cell lines.4. The elevation of human colorectal carcinoma cells invasion abilityand VEGF production induced by HGF may be caused by theHGF-inducing activation of MEK/ERK1/2 and PI3K/AKT signalingpathways.