The Role Of ERK/MAPK Signaling Pathway In The Proliferation And Migration Of SW620

Objective:Colorectal cancer (CRC) is a common tumor, threating human health.The genesis and progression are relate to the abnormal intracellular signal pathways transmission.The level of Hepatocyte Growth Factor(HGF) of serum in colorectal cancer patients is significantly higher than that in normal people. The later stages is associated with the higher level of HGF. Moreover, the level of HGF in patients with hepatometastasis is higher than that without hepatometastasis in colorectal cancer patients. HGF is a peptide that Secreted by many kind of cells, it plays an important role in mitosis, organizations, inducting migration of epithelial cells, invasion of cancer cells and angiogenesis in cancer tissue. It is considered playing the role of growth and metastasis in colorectal cancer,it is becoming the novel target for the treatment of colorectal cancer by inhibiting the role of HGF/c-Met take part in growth,invasion and metastasis.HGF can activate the tyrosine kinase of its receptor c-Met and play the role of cell proliferation, apoptosis, differentiation by binding to it, and then activate the downstream signal pathways leding to its substrates phosphorylated including phospholipase Cγ(PLCγ), phosphoinositide 3-kinases- protein kinase B (PI3K/AKT/PKB), mitogen activated protein kinase (MAPK), growth factor receptor-bound protein 2 (Grb2), Grb2-associated binder 1 (Gab1) and so on. In the previous study, we found HGF can promote the proliferation and migration of SW620 cells. But the mechanism remains unclear.MAPK is one of intracellular signaling pathways, which play a variety of physiological functions such as cell proliferation, apoptosis, differentiation,and so on. extracellular signal-regulated kinase(ERK) signal pathway which is one of MAPK plays the role of proliferation and differentiation.It is necessary of normal tissue in regularing growth and differentiation,abnormal activated is associated to tumor occurrence and development.The key molecules in the ERK signaling pathway,including small G-protein Ras and its downstream Raf kinase,MEK1/2 and ERK1/2.extracellular signals transfer the information from extracellular to intracellular by activing the key molecules to regulate cell proliferation, differentiation,tissue formation and other biological behaviors.Inhibiting the biological activity of HGF/c-Met can by HGF competitive inhibition,RNA interference technology and others, it has not been reported by blocking ERK/MAPK pathway using MEK inhibitor U0126 to inhibit the proliferation,cell cycle and invasion that activated by HGF.To investigate the effects of ERK/MAPK signaling pathway in proliferation and invasion of SW620 cell that activated by HGF,we use MEK inhibitor U0126 blocking ERK/MAPK pathway, in the hope of providing novel treatment for tumor.Methods:1 The effect of ERK/MAPK signaling pathway on the proliferation of SW620 cells that activated by HGF was examined by MTT.2 The effect of ERK/MAPK signaling pathway on the cell cycle and apoptosis of SW620 cells that activated by HGF were examined by Flow Cytometry (FCM).3 The effect of ERK/MAPK signaling pathway on the migration of SW620 cells that activated by HGF was examined by Scratch test.Results:1 U0126 inhibited the proliferation of SW620 that activated by HGF,but did not show concentration-dependent manner.SW620 cells were treated with DMSO(0.1% v Volume)and U0126 (0.5, 1, 2, 4 and 8μmol/L) for 48 h.The proliferation of SW620 was inhibited only in 4μmol/L and 8μmol/L U0126 group,the inhibition ratio of proliferation were 24.6%,28.4%(P <0.05),but there was no difference between groups (P>0.05). 2 U0126 inhibited the proliferation of SW620 that activated by HGF possibly by inhibiting cell cycle.The difference of cell number of G1 phase,S phase and PI were significant between experiment groups (with the concentration of 0.5,1,2,4,8μmol / L U0126) and control group after 24h (P<0.05).However there was no difference of G2 phase between groups(P>0.05),The difference of cell number of G1 phase,S phase and PI were significant between groups (4μmol/L U0126 group,8μmol/L U0126)and 2μmol/L U0126 group(P<0.05).The cell mumber of G1 phase,S phase and PI were (52.51±8.76)%,(35.97±9.84)% and (47.49±8.76)% in control group,the cell mumber of G1 phase,S phase and PI were(52.51±8.76)%, (35.97±9.84)%, (47.49±8.76)% in 8μmol/L U0126 group.The apoptosis rate was no significant different between experimental groups and control group.we speculated that U0126 inhibites the proliferation of SW620 cells that activated by HGF promoted by inhibiting cell cycle.3 U0126 inhibited the migration of SW620 that activated by HGF.8μmol/L of U0126 show inhibition in the migration of SW620 that activated by 20ng/ml of HGF play with 24h,inhibition ratio was 60.9% (P<0.05).4μmol/L of U0126 show inhibition in the migration of SW620 that activated by 20ng/ml of HGF after play with 48h,inhibition ratio was 46.5% (P<0.05).There were no difference in inhibiting the migration between experiment groups(P>0.05) after 48h.0.1% volume concentration of DMSO did not show inhibition in the migration of SW620(P>0.05).Conclusion:ERK/MAPK signaling pathway involves in the proliferation and migration of SW620 activated by HGF.