CELL INTELLIGENCE · 肿瘤细胞治疗研究

Myxoma virus (MyxV) is a rabbit-specific poxvirus. However, its ability to selectively target tumor cells has established it as a safe and effective anticancer therapy. To strengthen its preclinical efficacy, transgenes that can prolong cancer cell infection and enhance anti-tumor effector functions are currently being investigated.

We engineered MyxV armed with CD47, to turn on a 'do not eat me' signal within infected cells with actively replicating viruses, and with IFN- to further activate host immune anticancer responses. Tumor suppressive activities were significantly enhanced by the dual-armed MyxV_CD47/IFN- compared to parental MyxV or single-armed MyxV_CD47 or MyxV_IFN- .

In addition, significant increases in IFN- + CD8+T-cells and CD4+ T-cells populations within tumor-infiltrating lymphocytes (TIL) were observed after MyxV_CD47/IFN- treatment.

Notably, all groups treated with MyxV showed a marked reduction in Foxp3+ CD4+ regulatory T-cells (Tregs) within TIL.

We also show that MyxV infection induces PD-L1 up-regulation in cancer cells, and combinational treatment of MyxV with anti-mouse PD-L1 antibodies ( PD-L1) further controlled tumor burden and increased survival in the syngeneic melanoma model B16F10.

Our data demonstrate that a CD47 and IFN dual-armed MyxV is an effective oncolytic viral immunotherapeutic.

These findings strongly support further preclinical investigations to develop next-generation MyxV-based immunotherapy approaches.