Effects Of Liver-targeted Drugs On Expression Of Immune-related Proteins In Hepatocellular Carcinoma Cells

Objective : Hepatocellular carcinoma(HCC)is one of the most common malignant cancers in the world.Its occurrence process is mostly hidden and prone to early metastasis and infiltration to adjacent and distant tissues with a high degree of malignancy and has become the fourth leading cause of cancer deaths worldwide.The molecular mechanisms involved in the development and metastasis of HCC are complex,many patients with advanced liver cancer do not qualify for surgical treatment or still have recurrence after radical surgery.In recent years,molecule-targeted drugs represented by tyrosine kinase inhibitor,have achieved remarkable results in the treatment of advanced HCC.Molecule-targeted drugs are characterized by strong specificity and low toxicity,but the clinical research of these drugs still exhibits many difficulties,such as poor target specificity.With the in-depth study of the tumor immunological theory,therapies based on overcoming the tumor immune escape to produce a specific effective tumor immune response has gradually become a hot topic in tumor research.In particular,immune checkpoint blockades(ICBs)have made a breakthrough in cancer therapy.We hope that by studying the effects of liver-targeted drugs on the expression of immune-related proteins in hepatocellular carcinoma cells,we will find a potential link to further guide the clinical drug use.Methods:Human hepatoma Hep3 B cells were used to establish liver cancer xenografts by inoculating 40 BALB/c nude mice.The following five groups of mice(8 mice per group)were randomly set up: lenvatinib group,apatinib group,sorafenib group,regorafenib group,and dimethyl sulfoxide(DMSO)group.The tumor-bearing mice of lenvatinib group,apatinib group,sorafenib group,regorafenib group were treated with100 mg/kg,50 mg/kg,100 mg/kg and 20mg/kg of the respective molecule-targeted drug,respectively and via gavage once a day for two weeks,and mice of the DMSO control group were analogously treated with 100 ?L/20 g DMSO.The size of the tumor body was measured every 2 days,and the tumor growth curve was plotted to compare the growth rate of subcutaneous liver cancer xenografts.The mice were executed by dislocation of the cervical vertebra,and their tumors were removed after 24 h of treatment.We performed real-time polymerase chain reaction(PCR)assays for PD-L1 and B7-H3 m RNA,and the expression of PD-L1 and B7-H3 protein was assessed by immunohistochemistry(IHC)and western immunoblotting.Statistical analysis was performed with SPSS? version 23.0.All quantitative data are presented as the mean ±standard deviation(SD).One-way analysis of variance was used to compare differences between groups.Differences with values of p<0.05 were considered statistically significant.Result:Compared with the control group,The tumor growth rate of the lenvatinib group,apatinib group,sorafenib group,and regorafenib group were significantly lower.Real-time PCR results suggested that the PD-L1 m RNA expression in the lenvatinib group was significantly higher than that in the control group,while its expression in the regorafenib group was significantly lower than that in the control group(both p<0.05).However,no significant difference in the B7-H3 m RNA expression was found between experimental group and control group.IHC and Western immunoblotting suggested that,compared with the control group,PD-L1 protein was increased in the lenvatinib group,while its expression in the regorafenib group was decreased.However,no significant difference was found in the m RNA and protein expression of B7-H3 between experimental group and control group(p>0.05).Conclusion:Lenvatinib and regorafenib affected the expression of PD-L1 in the process of anti-HCC.The combination of liver-targeted drugs and immune checkpoint inhibition could play a greater role in the treatment of HCC.