Effect Of Overexpression Of Colony Stimulating Factor-1 Receptor On The Growth Of Nasopharyngeal Carcinoma Xenografts In Nude Mice And Its Mechanism

Objective: To investigate the effect of overexpression of colony stimulating factor-1 receptor(CSF-1R)on the growth of human nasopharyngeal carcinoma 6-10 B xenografts in nude mice and its related mechanism.Methods: CSF-1R overexpressed lentivirus was constructed to transfect into human nasopharyngeal carcinoma 6-10 B cells.The 6-10 B cells transfected with CSF-1R(transfection),6-10 B cells with empty vector(NC)and 6-10 B cells(mock)were planted under the skin of nude mice.The volume of transplanted tumor in nude mice was measured once every 3 days,and the growth curve of tumor was calculated.The effect of overexpressing CSF-1R on the growth of human nasopharyngeal carcinoma 6-10 B nude mice was observed.After 3 weeks of tumor cell implantation,all nude mice were sacrificed.The tumor tissue samples were taken,the tumor weight was weighed.The pathological changes of transplanted tumors were observed under light microscope,and the expression of CSF-1R protein in human nasopharyngeal carcinoma xenografts was detected by immunohistochemistry and Western blot.RT-qPCR was used to detect CSF-1R in nude mice xenografts on the expression of mRNA.Western Blot was used to detect the relative expression of proliferation-related factors,invasion-related factors,apoptosis-related factors and autophagy-related factors in transplanted tumor tissues,and to explore the mechanism of CSF-1R promoting tumor growth.Results: Three groups of tumor xenograft models were successfully constructed.The tumor growth curve showed that the transfection group had significantly faster growth than the negative control group and the mock group(P<0.05).At the end of the experiment after 3 weeks,the volume of xenografts in the transfection group was significantly higher than that in the NC group and the mock group(P<0.05).The tumor mass of the transfection group was significantly bigger than that in the NC group and the mock group(P<0.05).The results of staining showed that three groups had obvious apoptosis and necrosis of tumor cells.The results of immunohistochemistry showed that CSF-1R was weak in the NC group and the mock group,while was strongly positive in the transfection group.The Western Blot results showed that the positive expression of CSF-1R protein in the transfection group was higher than that in the NC group and the mock group.The RT-qPCR results showed that the relative expression of CSF-1R mRNA in the transfection group was higher than that in the NC group and the mock group.The results of Western blot showed that the relative expression of proliferation-related factors cyclin D1,metastasis-associated factor MMP2,anti-apoptotic factor Bcl-2,autophagy-related factors LC3 II and Beclin 1 in the transfection group were higher than those in the NC group and the mock group(P<0.05).And the relative expression of apoptosis-related factor Bax and autophagy-related factor P62 protein decreased in transfection group(P<0.05).There was no significant difference between NC group and mock group(P>0.05).The results of related pathway proteins showed that PI3 K,AKT,p-AKT and mTOR increased with the overexpressing of CSF-1R,and the difference between the three groups was statistically significant(P<0.05).Conclusion: 1.Overexpression of CSF-1R gene can promote the growth of human nasopharyngeal carcinoma xenografts in nude mice via increasing cellproliferation with CSF-1R,inhibiting apoptosis and promoting autophagy.2.The mechanism of CSF-1R promoting the growth of nasopharyngeal carcinoma in nude mice may be related to the activation of PI3K/AKT/mTOR signaling pathway.