Beyond the Limit: MYC Mediates Tumor Immune Escape

MYC is an aberrantly regulated transcription factor implicated in approximately 70% of human tumors, where it extensively modulates signaling pathways associated with cancer progression. Inactivating MYC has been shown to inhibit tumor growth and even induce sustained tumor regression across various cancer types, a phenomenon referred to as oncogene addiction. However, in vitro studies reveal that the knockout or knockdown of MYC in numerous tumor cell lines does not necessarily result in cell death, despite these tumors exhibiting MYC addiction in vivo. This discrepancy suggests that the unique tumor microenvironment in vivo may play a critical role in facilitating MYC addiction in cancer cells. MYC is also widely acknowledged for its role in mediating the immune evasion of tumor cells. Nevertheless, due to the extensive regulation of cellular gene expression by MYC and the incomplete understanding of the mechanisms underlying tumor immune escape, the precise pathways through which MYC influences tumor immune evasion remain inadequately elucidated. Recent years have seen the identification of novel tumor immune escape mechanisms, some of which have been demonstrated to be directly or indirectly regulated by MYC. For instance, MYC may contribute to immune evasion by modulating the expression of argininosuccinate synthetase 1 (ASS1), a key enzyme involved in arginine biosynthesis. Herein, in this study, we explore some novel potential mechanisms through which MYC facilitates the immune evasion of tumor cells, alongside a combined therapeutic approach targeting MYC and employing immunotherapy based on this mechanism. Furthermore, we suggest that targeting proteins interacting with MYC to modulate its expression and function may serve as an alternative strategy to direct MYC targeting, thereby expediting the clinical translation of combination therapies.