Targeting TNK2/ACK1 reverses the immunosuppressive tumor microenvironment and synergizes with immunochemotherapy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains highly lethal due to its aggressive nature and limited treatment options, with the efficacy of immunotherapy constrained by a uniquely immunosuppressive tumor microenvironment (TME). In this study, we identify TNK2/ACK1 as a key regulator of the immunosuppressive TME in PDAC. TNK2/ACK1 is significantly upregulated in PDAC, at least in part via gene amplification and KRAS-G12 mutations. Mechanistically, TNK2/ACK1 directly phosphorylates and activates STAT5A to induce the expression of the immune checkpoint HVEM, which suppresses CD8⁺ T-cell function via its receptor BTLA. Pharmacologic targeting of TNK2/ACK1 with AIM100 or (R)−9b enhances CD8⁺ T-cell activation and cytotoxicity while reprogramming the TME. Furthermore, combining TNK2/ACK1 inhibitors with anti-PD-1 immunotherapy or with nab-paclitaxel plus gemcitabine demonstrates promising antitumor efficacy in both allograft and spontaneous PDAC models. Overall, our findings reveal a mechanism of immune evasion and provide a potential framework for developing tailored immunotherapeutic strategies in PDAC. Pancreatic ductal adenocarcinoma (PDAC) is highly lethal, with treatment effectiveness, including immunotherapy, limited by immunosuppressive tumor microenvironment. This study identifies TNK2/ACK1 as a driver of immune evasion in pancreatic cancer via STAT5A-HVEM signaling that disables CD8⁺ T cells while TNK2 inhibition restores antitumor immunity and synergizes with anti-PD-1 and chemotherapy in PDAC models.