Research On The Effect Of Oncolytic Herpes Simplex Virus Type 2 On Inhibiting Colorectal Cancer Liver Metastasis In Mice

Objective: To study the effect of herpes simplex virus type 2 on inhibiting colorectal cancer liver metastasis and overall immunity in BALB/c mouse.Methods: In this study,we selected HSV-2 knocked out the gene of ICP34.5 and ICP47,and inserted the gene of GM-CSF as therapeutic virus.CCK-8 cell proliferation assay was used to test the oncolytic activity of o HSV2 on CT-26 cells in vitro.Liver pathological sections confirmed that the liver metastatic nodules of mice were poorly differentiated adenocarcinoma.By animal experiments to evaluate the effect of o HSV2 on inhibiting CT-26 cell line colorectal cancer liver metastasis and the survival time of the treatment group and the control group.The percentage of immune cells in the peripheral blood of mice was analyzed by flow cytometry.Results: 1.The infected CT-26 cells with oHSV2 became round and floating,and the MOI and the growth activity of CT-26 cell was inverse association.The result showed that o HSV2 possessed of a strong oncolytic activity on CT-26 cells in vitro.2.After subcutaneous intratumoral injection of o HSV2 in mice,the volume of subcutaneous xenograft tumor in the o HSV2 treatment group was significantly smaller than the control group.In addition,there was no significant difference in the body weight between the two groups of mice,indicating that o HSV2 can safely and effectively inhibit the growth of CT-26 cell subcutaneous xenograft tumor.3.The livers of the two groups of were dissected and dissociated.The liver of the o HSV2 treatment group had a well-defined,ruddy and lustrous,whereas the control group lost liver morphologies and dullness.At the same time,liver pathological sections confirmed the liver metastasis tumor nodules were poorly differentiated adenocarcinoma in both groups.4.In the model of CT-26 cell line BALB/c mouse colorectal cancer liver matastasis,The number of liver metastatic tumor nodules in the o HSV2 treatment group was significantly less than the control group,and was better at MST than the control group.It showed o HSV2 had a obviously effect on inhibiting colorectal cancer liver metastasis.5.With flow cytometry analysis of the peripheral blood of both groups showed the percentage of CD4~+ T,CD8~+ T,and NK cells in the peripheral blood of the o HSV2 treatment group was significantly higher than the control group,the result revealed o HSV2 can significantly elevate the percentage of CD4~+ T,CD8~+ T,and NK cells in the peripheral blood of mice.Conclusions: 1.In vitro o HSV2 had a strong oncolytic activty on CT-26 cells.2.o HSV2 can safely and effectively inhibit the growth of CT-26 cell subcutaneous xenograft tumors in mice.3.The spleen-preserving intrasplenic injection was a safe,effective and practical method for constructing the model of colorectal cancer liver metastasis.4.o HSV2 can significantly inhibit liver metastasis in mice with colorectal cancer,and prolong the MST.5.o HSV2 can obviously elevate the percentage of CD4~+ T,CD8~+ T and NK cells in the peripheral blood of mice.