mTORC1 upregulates B7-H3/CD276 to inhibit antitumor T cells and drive tumor immune evasion [RNA-seq]

Immune checkpoints are often expressed on tumor cells; it remains a prevailing need to identify the mechanisms underlying their regulation and therapeutic benefit. The immune checkpoint molecule B7-H3 is upregulated in many human tumors, including those with high mechanistic/mammalian target of rapamycin complex (mTORC1) activity. Still, its role in tumor immunity and the impact of B7-H3-targeted therapy on the tumor immune microenvironment are largely uncharacterized in mTORC1-hyperactive tumors. Here, we used a syngeneic murine model of tuberous sclerosis complex (TSC), a model of mTORC1 hyperactivity, to assess the mechanisms by which B7-H3 remodels the tumor microenvironment. We performed gene expression profiling analysis using data generated from RNA-seq of bulk tumors from subcutaneous B7-H3 knockdown and control TSC2-deficient 105K cells or sorted tumor cells isolated by MACS mouse tumor cell isolation kit (Miltenyi Biotec). Overall design: Comparative mRNA expression profiling analysis of RNA-sequencing from bulk tumors or sorted tumor cells isolated from wild-type C57BL/6J mice carrying subcutaneous TSC2-deficient B7-H3 knockdown or control tumors.