水疱性口炎病毒对小鼠乳腺癌4T1细胞荷瘤小鼠抗肿瘤免疫、移植瘤生长与肺转移的影响OA北大核心CSTPCD

Objective:To investigate the effects of wild-type vesicular stomatitis virus strain(VSV-IN)on immunomodulation and tumour metastasis in mouse triple negative breast cancer(TNBC)4T1 cell transplantation model mice.Methods:After VSV-IN infected 4T1 cells with MOI=1,MOI=10 and MOI=100 for 12,24 and 48 h,4T1 cell mortality was detected by CCK-8 method,migration ability by scratch healing assay,and the expressions of E-cadherin,MMP-2 and MMP-9 mRNA by qPCR.The fat pads of female BALB/c mice were inoculated with 0.1 mL of 4T1 cells with a cell density of 1×106 cells/mL to construct a 4T1 cell-loaded mouse model.When the tumour volume reached 200 mm3,the mice were injected intratumorally with PBS,taxol(TAX)(15 mg/kg),and VSV(1×106 pfu)once a week,respectively.After 4 administrations,mice were executed,stripped of intact grafted tumour tissues,and tumour volume and mass were measured.Histopathological sections of the lungs were stained with H-E,and tumour metastatic nodules of the lungs were observed.The proportion of T-cell subpopulations in the spleen was detected by flow cytometry.The levels of serum IL-6 and TNF-α were detected by ELISA.The expression levels of migration-related proteins in mammary gland tumours were analysed by using the online analysis of GEPIA.The expressions of MMP-2,MMP-9 and E-cadherin in mouse tumours were detected by immunohistochemistry,and the affinity of G and M proteins of VSV-IN and ERK2 and E-cadherin was predicted by protein-protein docking technology.Results:The mortality rate of 4T1 cells after 48 hours of VSV treatment at MOI=10 and 100 were significantly higher than that of the control group(P<0.01).Compared with that of the control group,the cell migration rate of the VSV-IN group(MOI=10)was significantly lower(P<0.01),and the relative expression of MMP-9 mRNA was significantly lower(P<0.05).Compared with those in the mice of the control group,transplanted tumours in the mice of the VSV-IN group grew more slowly,and their endpoint volume was significantly reduced(P<0.05).The number of lung metastatic nodules in the mice of the VSV group was significantly less than that of the control group([12.86±1.86]vs[24±3.67],P<0.01).The proportions of splenic CD4+T and CD8+T cells in the VSV group were significantly higher(both P<0.05).The serum TNF-α and IL-6 levels were significantly higher(both P<0.01).GEPIA tool analysis revealed that the expression levels of E-cadherin and MMP-9 were higher in breast cancer tissues than in paracancerous tissues(P<0.05).The expression of MMP-9 in the tumour cells of the mice in the VSV-IN group was significantly lower than that in the control group(P<0.05).The binding free energies of G and M proteins of VSV-IN to ERK2 were-11.7 kcal/mol and-6.4 kcal/mol,respectively.Conclusion:Wild-type VSV-IN inhibits the growth and metastasis of transplanted tumours in 4T1 tumor-bearing mice,which may be related to its promotion of anti-tumour immunity and modulation of the expression of migration-related proteins.