The Role And Regulation Machanism Of Sphingosine-1-phosphate Receptor Regulator Fingolimod In Treating Renal Carcinoma

Objective:Renal carcinoma is one of the most common malignant tumor in urinary system.No reliable biologic tumor markers is available for renal carcinoma screening at early stage.Distal metastasis has already happened on quite a few patients when their diagnosis are confirmed.In recent years,immunotherapy has became the research focus in treating metastatic renal carcinoma gradually.For another,sphingosine-1-phosphate receptor regulator is focus direction in the field of immunotherapy besides the immunocheckpoint inhibitor.We set up the subcutaneously transplanted mice model of renal carcinoma and evaluated the effect of Fingolimod(FTY720,a kind of Sphingosine-1-phosphate receptor regulator)in treating renal carcinoma.Furtherly we explored the potential regulation mechanism of Sphingosine-l-phosphate receptor regulator.Method:Mice models transplanted mouse Renca tumor cell to the subcutaneous of mice were randomly divided into 4 group:Placebo control group,CTX(100mg/kg)group,FTY720 low-dose(5mg/kg)treatment group,FTY720 high-dose(10mg/kg)treatment group.The medicine was given from the second day of inoculation:normal saline was given to Placebo control group.Treatment continued for 3 weeks.Mice were sacrificed after the treatment was finished.We stripped the turner ntegrally and weigh them to evaluate the treatment outcome of FTY720.Western blot was performed to detect the expression of key protein in relevant signal pathway:Caspase-3、PARP、Bcl-2、Bcl-XL、Bok、Akt、p-Akt(S473)、p-Akt(T308)、Cyto-c、Fas、Fasl、HIF-a and furtherly we measured the difference of expression level for those protein between different groups by gray scale analysis.Result:The subcutaneously transplanted mice models of mouse renal carcinoma Renca cell line were established successfully.Tumor formation rate and survival rate were both 100 percent.Totally 32 mice were included and randomly divided into four groups,FTY720 high-dose treatment group.When the treatment was finished,the tumor of mice in FTY720(10mg/kg)group were significantly light than those in Placebo control group.The tumor inhibition rate is 22.1 percent(p<0.05).The result of western blot indicated that FTY720(10mg/kg)can significantly promote the cleavage of Caspase-3.The result of gray scale analysis showed that the level of two subunit of Caspase-3(19kD and 17kD)in FTY720(10mg/kg)raised 101 and 121 percent respectively(p<0.05).FTY720(10mg/kg)can also decrease the phosphorylation level of Akt,which falled by 23 percent(p<0.05).The level of Fas promoted 25 percent(P<0.05)compared with Placebo control group.No significant difference was found in other relevant protein.Conclusion:High-dose of FTY720 can effectively inhibit the malignant proliferation of renal carcinoma by inducing apoptosis of renal carcinoma cell via Fas and death receptor pathway.Moreover High-dose of FTY720 can also inhibit the activation of PI3K/Akt pathway to inhibit renal carcinoma.