RESUMO
Recent clinical studies have shown that mutation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene in cancer cells may be associated with immunosuppressive tumor microenvironment (TME) and poor response to immune checkpoint blockade (ICB) therapy. Therefore, efficiently restoring PTEN gene expression in cancer cells is critical to improving the responding rate to ICB therapy. Here, we screened an adeno-associated virus (AAV) capsid for efficient PTEN gene delivery into B16F10 tumor cells. We demonstrated that intratumorally injected AAV6-PTEN successfully restored the tumor cell PTEN gene expression and effectively inhibited tumor progression by inducing tumor cell immunogenic cell death (ICD) and increasing immune cell infiltration. Moreover, we developed an anti-PD-1 loaded phospholipid-based phase separation gel (PPSG), which formed an in situ depot and sustainably release anti-PD-1 drugs within 42 days in vivo. In order to effectively inhibit the recurrence of melanoma, we further applied a triple therapy based on AAV6-PTEN, PPSG@anti-PD-1 and CpG, and showed that this triple therapy strategy enhanced the synergistic antitumor immune effect and also induced robust immune memory, which completely rejected tumor recurrence. We anticipate that this triple therapy could be used as a new tumor combination therapy with stronger immune activation capacity and tumor inhibition efficacy.
RESUMO
L-10 has been recognized as an irnmune suppressive cytokine which inhibits Ag-specific activation and proliferation of T cells. It also inhibits Ag presenting capacity of monocyte/macrophage and down-regulates monokine production. However it has also shown that IL-10 has stimulatory effect on immune effector cells in recent studies. This report shows that IL-10 has direct stimulatory effect on antitumor cytolytic activity suppressed by TGF-B. To assess the effect of IL-10 on cytolytic activity against tumor, spleen cells prepared from tumor-bearing mice were cultured with mitomycin C-treated MOPC-315 cells in the presence of IL-10. Unexpectedly, IL-10 was able to reverse the cytolytic activity suppressed with TGF-B. The stimulatory effect of IL-10 was dependent on the addition time of IL-10. At day 0, 4, those effects were shown higher than those of the other days. Also, the stimulatory effect of IL-10 showed specificity against MOPC-315 tumor cells. To elucidate the role of endogenous IL-10, TGF-B in MLTC cultures, anti-IL-10 and anti-TGF-B mAb were used. The inhibition of IL-10 release in MLTC cultures by using anti-IL-10 mAb resulted in the suppression of cytolytic activity against MOPC-315 tumor cells. Taken together, although IL- 10 has been recognized as a strong immunosuppressive cytokine derived of tumor cells, IL-10 showed the direct stimulatory effect on the antitumor cytolytic activity of spleen cells.