Figure 4.

ISG15 overexpression suppresses ovarian cancer growth in orthotopic mouse models. (A) OVCA432 ovarian cancer cells were intraperitoneally injected into athymic nude mice. A significant increase in tumor burden was observed in mice injected with OVCA432 cells transduced with the ISG15 specific shRNA when compared with scrambles shRNA transduced control mice. To further evaluate the effect of ISG15 overexpression on ovarian cancer growth in an immune-competent microenvironment, mouse ovarian cancer cell lines (B) IG10 and (C) ID8 transduced with the full-length mouse ISG15 expression construct were intraperitoneally injected into immuno-competent C57BL/6 mice. Animal study results indicated a significant decrease in tumor weight for mice injected with cell lines transduced with the full length ISG15 expression construct when compared with those transduced with the control vector. To evaluate the effects of ISG15 expression on ovarian cancer progression in a T cell-depleted environment in vivo, both (D) IG10 and (E) ID8 cell lines were injected into C57BL/6 nude mice. The results showed a significant decrease in tumor size in mice injected with ISG15 transduced cancer cells when compared to those injected with the mock-transduced cells.