Molecular Mechanism Of LKB1 On Angiogenesis And Metastasis Of Colorectal Cancer

Objective: According to the small interfering RNA silencing LKB1 gene expression of angiogenesis and metastasis of colorectal cancer molecular mechanism to explore the role of metformin in LKB1-AMPK-AKT signaling pathways. It can provide new molecular targets for gene therapy of colorectal cancer, the mutation or missing LKB1 renovation is expected to become the new method for the treatment of colorectal cancer angiogenesis and metastasis.Methods: Immunohistochemical method of SP was used to exam the trend of LKB1 expression in cases of colorectal cancer tissue chips.To culture human colorectal cancer LoVo cells in vitro and The chemically synthesized siRNA targeting LKB1(LKB1siRNA) was transfected into LoVo cells with high metastatic potential by LipofectamineTM2000.At the same time, to detect the effect of of metformin on colorectal cancer LoVo cell proliferation by CCK8 kits.Then the transfected colorectal cancer cells was intervented with appropriate concentration. Observed the changes of cell morphology by inverted microscope.The exprssion of LKB1 and P-LKB1,AMPK and P-AMPK,AKT and P-AKT by Western-Blot.Boyden chamber method was used to detect the ability of migration and aggressivity of the transfeced colorectal cancer LoVo cell with metformin interventied.Results: About 48 hours after transfection LKB1 siRNA,the amount of LKB1 and P-LKB1 expression reduce significantly,P-AMPK expression quantity also significantly reduced,and the P-AKT expression quantity was increased,AMPK and AKT expression has no obvious change by Western Blot detection.The inhibition rate was about 50% with the concentrations of 20Mmol/L metformin after 48 h.The quantity of LKB1,P-LKB1,AMPK and AKT protein expression almost did not increase and the P-AMPK expression quantity was increased,thereby inhibiting the expression of P-AKT with the intervention of 20Mmol/L metformin.Conclusion: After the transfection of the LKB1-targeted siRNA into LoVo cells, the expression of RIP1 gene has been knockoutted effectively.The lack of LKB1 inhibit phosphorylation of AMPK of its downstream pathway, which promote the activation of AKT.The lack of LKB1 gene promote tumor cell proliferation and angiogenesis and enhances the colorectal cancer cell migration and invasion force. In LKB1-AMPK-AKT signaling pathways,metformin can hinder protein synthesis within the tumor cells directly and inhibit tumor cell proliferation by promoting the phosphorylation of AMPK.