Effect Of Metformin Combined With Radiation On Proliferation And Apoptosis Of Colorectal Cancer Cell Lines SW480and HCT116

Objective:To research the effect of proliferation inhibition and apoptosis induced by metformincombined with radiation in colonrectal cancer cell lines SW480and HCT116, and the possiblemechanism.Methods:1. We used cck-8to detect the proliferation inhibition on human colonrectalcancer cells by metformin, X-ray, metformin combined with X-ray and so on.2. Plate clone formation assay and flow cytometry were used to detect survivaland apoptosis on human colonrectal cancer cells by metformin, X-ray, metformincombined with X-ray and so on.3. To find new clues for subsequent mechanism research, we used geneexpression profile to analyse the expression difference gene on colonrectal cancer celllines SW480and HCT116by control, metfromin, X-ray and combined group.4. Quantify PCR was used to analyse the results of gene chip and detect themRNA expression of ADORA1, Caspase-3, Caspase-9and Bcl-2.5. We used Western Blotting to detect the protein expression.Results:1. CCK-8results showed that the proliferation of cells were restrained bymetformin (1,5,10mmol/l) which had the dose and time-dependent manner. And theproliferation were restrained by X-rays (2,4,6,8,10,12Gy), but the effect wasobviously of8Gy. Meanwhile, the effect of proliferation inhibition was significanthigher by metformin (1mmol/l) combined with X-rays (8Gy) than alone group(P<0.05).2. Plate clone formation assay results showed that metformin and X-rays couldsuppress cells viability, and the effect of suppression was significant higher bycombination group than alone group (P<0.05). 3. Flow cytometry results showed that the effect of inducing apoptosis wassignificant higher by combination group than alone group (P<0.05).4. We found many expression difference genes on SW480and HCT116whichwere treated with metfromin (1mmol/l) from gene expression profile. And we selectedADORA1(Adenosine A1Receptor) to research which had not reported in anti-tumorof metformin and apoptosis related gene.5. We verified the result of gene chip by PCR, the mRNA expression ofADPRA1, Caspase-3and Caspase-9in combination group were higher than alonegroup, but Bcl-2were lower.6. Western Blotting results showed that the protein expression of p-AMPK,ADORA1, Caspase-3, Caspase-9were significant higher in combination group thanalone, and p-mTOR and Bcl-2were lower.Conclusion:1. Metformin and X-rays can inhibit the proliferation and viability of colonrectalcancer cell lines SW480and HCT116, and the effective in combination group is betterthan alone.2. The effect of apoptosis by combination group is significant higher than alone.3. The anti-tumor effect of metformin combined with X-rays relate to activationof AMPK and inactivation of mTOR.4. ADORA1upregulation may be related to the induced apoptosis effect ofmetfromin.