Project description:The Aurora-A inhibitor alisertib shows encouraging activities in clinical trials against multiple malignances including advanced breast cancer. However, its mechanism of action remains unclear, especially regarding how the inflammatory microenvironment is involved in the efficacy of alisertib. Here, we demonstrated that Aurora-A inhibition directly reshapes the immune microenvironment through removal of tumor-promoting myeloid cells and enrichment of anti-cancer T lymphocytes, which restores a tumor-suppressive microenvironment and significantly contributes to the regression of murine mammary tumors. Mechanistically, the Aurora-A inhibitor effectively eliminated myeloid cells including myeloid-derived suppressor cells (MDSCs) and macrophages in tumors by triggering apoptosis of these cells. Further, Aurora-A inhibition could disrupt the immunosuppressive functions of MDSCs through inhibiting Stat3 mediated ROS production. These alterations led to significant increases in the proportion and the number of CD8+ and CD4+ T lymphocytes, which efficiently inhibited the proliferation of tumor cells. In summary, these data revealed that in addition to suppressing the proliferation of tumor cells, Aurora-A inhibitor directly modulates and restores an anti-tumor immune-microenvironment in breast cancer. Intriguingly, Aurora-A inactivation combined with PD-L1 blockade showed synergistic efficacy in the treatment of mammary tumors, providing an effective strategy for clinical trials of chemo-immunotherapy in breast cancer.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and it’s co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and it’s co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and it’s co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:Innate immune checkpoint has emerging as a highly potential target for cancer immunotherapy in recent years. The CD47-SIRPα axis is the best-studied innate checkpoint in cancer. However, the transcription profile of tumor cell duiring CD47-SIRPα blockade therapy remains unclear.
Project description:SIRPa-CD47 “don’t eat me” checkpoint axis plays a critical role in defining anti-tumor activities of macrophages within the tumor microenvironment. However, targeting this axis with anti-CD47 antibodies to improve anti-tumor responses in clinical trials has proven challenging. Here, we demonstrated that iPSC-derived macrophages (iMacs) with ablated SIRPa yield a superior antitumor effect in conjunction with cancer-targeted antibodies (Ab) or chimeric antigen receptor (CAR) against a variety of CD47-expressing tumors in vitro. Moreover, SIRPA-KO protected macrophages from Ab- or CAR-driven exhaustion, allowing for efficient phagocytosis of tumors after multiple rounds of cancer re-challenges. Ablation of SIRPa in iMacs improved survival of mice grafted ovarian carcinoma and treated with anti-HER2 Abs, while anti-GD2 CAR iMacs with KO SIRPA demonstrated reduction of initial tumor burden in mice with metastatic neuroblastoma xenograft. Overall, our studies support the feasibility of using the iPSC platform to generate SIRPα-ablated iMacs that are resistant to CD47-mediated inhibition for therapeutic applications.