In Vitro And In Vivo Study Of Cytotoxicity Effects Of IL-2 Combined With Different Dosages Sorafenib Against Renal Cell Carcinoma

Objective:To investigate the cytotoxicity effects of IL-2 combined with different dosages sorafenib against renal cellular carcinoma cell line 786-O and its influence on tumor-bearing mice. Methods:Renal carcinoma cell 786-0 were cultivated. After 24 hours, we use IL-2(20umol/l) combined with different dosages sorafenib(6.9,13.8,20.8umol/l) against tumor cell.We investigated the inhibitory effects of IL-2 combined with different dosages on 786-O by MTT assay and cell apoptosis was analyzed by fiow cytometry using Annexin-V/PI. Preparing 786-O renal carcimona cell culture to logarithmic growth period, then trypsin digestion and adjusted cell concentration to 5×104cell/ml and injected it into the middle consequent subcutaneous 0.3ml.Tumor-bearing mice model was established and divided into four groups(blank control group,,high dose group,middle dose group and low dose group).The inhibitory effect and the tolerance were observed. Take the peripheral blood from tumou-bearing mice,serum levels IL-10 were measured by enzyme-linked immunosorbent assay in each group. Then use the immunohistochemical method to determine the VEGF and CD31 expression. Results:It was showed the inhibition of renal cancer cells proliferation by MTT method in each group. Compared with the control group, the combination groups have more significantly inhibited. With the increase of processing time and the concentration, the cell prolifeation inhibition is also gradually increasing, presenting a time-dose correlation. There are statistically significant difference in each groups(P<0.01).In 48 hours high doses group, this inhibitory rate up to(74.67±1.87)%.However, no significant differences were found in cell apoptosis in each group(P>0.01). Tumor-bearing mice model was successfully established, and in vitro experiment we observed tumor growth significantly lower in high dose group than in other groups. In vivo,we also observed the high dosages group was significantly higher inhibitory rate and apoptosis rate than other groups. But as the increase of the dose of drug,the tolerance is decreased.Body quality also have obvious differences in each groups(P<0.01).Compared with control group, IL- 10 exists obvious difference(P<0.01), and this difference also existd within each group(P<0.01).Immunohistochemical results found that in the tumor tissue the VEGF factor and CD31 molecule are also statistically significant differences. Conclusion: IL-2 combined with sorafenib could suppressed the tumor cell proliferation, but it could’t induce cell apoptosis.the two drugs could inhibit the kidney 786-O cell proliferation. Immunotherapy combined with target therapy can significant inhibit the growth of renal cellular carcinoma. But we should find a proper dosage,which can improve clinical effect and reduce adverse effect.In vitro experiments also showed a slowed tumor growth in mice.These effects may partly due to the combination drugs can down-regulate the expression of tumor immune suppressor(e.g. IL-10) and the growth of tumor blood vessels.