Effect Of 4-1BBL Gene Transfection On Growth Of Ovarian Cancer Cells And Its Immune Regulation In Vivo

OBJECTIVE: To observe the effect of 4-1BBL gene transfection on mouse ovarian cancer cell growth and its immune regulation.METHODS: Mouse ovarian cancer cell line (OVHM) was transfected with pcDNA3.1 and pcDNA3.1/4-1BBL through Lipofectamine?2000 mediation. The optimal drug concentration was determined (Hygro B 800μg/ml). The transfected cells were cultured with drug Hygro B and several cell clones were selected. The expression of 4-1BBL gene was detected by RT-PCR and FC and the steady high expression cell strain was selected. In order to observe the difference of cells growth, the growth curve was draw by counting the number of the tumor cells .Eighteen female B6C3F1 mice were randomly divided into three groups, with six mice in each group. The tumor size was observed after OVHM/4-1BBL cells , OVHM/pcDNA3.1 cells and parental OVHM cells were injected subcutaneously into B6C3F1 mice respectivly, and the tumor growth rate was recorded. The mice were killed at 21 day after tumor cells injection. The activity of CTL cells from the spleen of immunized mice was detected with lactate dehydrogenase (LDH) method using parental OVHM cells as the target cells.RESULTS: OVHM/4-1BBL cell lines was constructed successfully, and high expression of 4-1BBL gene can be detected in transfected OVHM/4-1BBL cells (77.82±3.45), while there was no difference between the parental OVHM cells and transfected OVHM/pcDNA3.1 cells (22.56±2.07 and 21.63±1.61). When comparing the proliferation rates of transfected and untransfected cells in vitro, there was no significant difference among the three groups (P > 0.05) . After cells were injected into mice, compared with the other two groups, delayed tumor formation and slowed tumor growth were observed in mice immunized with OVHM/4-1BBL cells, while there was no significant difference in tumor growth between OVHM group and OVHM/pcDNA3.1 group (P < 0.05). Tumor metastasis was not observed only in mice immunized with OVHM/4-1BBL cells. The CTL cytotoxicity immunized by OVHM/4-1BBL cells was significantly enhanced (P < 0.05) , while there was no significant difference between the other two groups (P > 0.05) .CONCLUSIONS: 4-lBBL gene transfection has no effect on the tumor cell growth in mitro. However, efficacious tumor immunity could be induced by 4-lBBL, which could delay the tumor formation, slow tumor growth, and decrease tumor metastasis .This study indicated that the 4-lBBL gene may be a candidate gene in immunogene therapy of ovarian cancer. OVHM/4-1BBL cell lines could be useful for the further gene study of 4-lBBL in vitro and vivo.