Abstract P53: Inhibition of STING/Galectin-9 Axis Sensitize Anthracyclines Treatment And Induce Anti-tumor Immunity

Abstract Anthracyclines, are a class of conventional and routinely used firstline chemotherapy drugs to treat breast cancer. Immunogenic cell death (ICD) is characterized by the exposure of danger signals that promote dendritic cell maturation and antigen presentation and is often associated with the induction of cancer cell-intrinsic IFN-I signaling pathway. In addition, among multiple chemotherapeutic drugs such as doxorubicin (Dox) is well-known to promote tumor immunogenicity by interfering with DNA synthesis. Galectin-9 (Gal-9), as a member of β-galactoside-binding protein family, has been demonstrated to induce T cell death and promote immunosuppression in the tumor microenvironment. In addition, it has been shown that some interferon (IFN) and interleukin (IL) factors can induce Gal-9 expression. However, the mechanism cross-talk between anthracyclines and Gal-9 immunecheckpoint inhibitor remains unknown. Here we show that doxorubicin induces PD-L1 expression in human breast cancer cell lines and animal models. Mechanistically, doxorubicin promoted IFNβ expression, which in turn enhanced doxorubicin-induced Gal-9. Furthermore, we discovered that doxorubicin induces tumor Gal-9 via STING upregulation. The combination of doxorubicin and anti-Gal-9 therapy compared with each agent alone significantly increased the therapeutic efficacy in vivo. Clinically, a higher Gal-9 and p-STING level in the tumor region of after-treatment anthracyclines as compared to before treatment is indicated in breast cancer tumor tissue. Taken together, our study demonstrates crosstalk between anthracyclines-induced ICD and tumor-associated immunosuppression and provides a novel therapeutic strategy by combining anthracyclines and Gal-9 antibody in breast cancer. Citation Format: Xian Sun, Wei-Jan Wang, Jilu Lang, Riyao Yang, Wan-Jou Shen, Linlin Sun, Mien-Chie Hung. Inhibition of STING/Galectin-9 Axis Sensitize Anthracyclines Treatment And Induce Anti-tumor Immunity [abstract]. In: Proceedings of Frontiers in Cancer Science; 2023 Nov 6-8; Singapore. Philadelphia (PA): AACR; Cancer Res 2024;84(8_Suppl):Abstract nr P53.