Cell-based immunotherapy has emerged as a promising strategy to overcome the limitations of conventional cancer treatments. Tumor Priming NKT-like Cells (TPNC), a unique lymphocyte subset co-expressing both T cell and NK cell surface markers while harnessing the cytotoxic killing mechanisms of both lineages, demonstrated superior anti-tumor activity over Cytokine-Induced Killer (CIK) cells against hematological malignancies including Multiple Myeloma, with validated in vivo efficacy. However, their therapeutic potential against solid tumors remains unexplored. In this study, we aimed to develop a novel NKT-like cell therapy targeting gastric cancer with peritoneal metastasis, a condition associated with poor prognosis and high mortality.
Cord blood mononuclear cells(CBMC) were cultured with irradiated ascites derived feeder cells from gastric cancer patients in the presence of defined cytokines, aiming to develop a new therapeutic Ascites priming NKT like cells(APNC). In vitro cytotoxicity was assessed against gastric cancer cell lines and patient-derived ascites cells, with CIK cells as a control. Anti-tumor efficacy was further evaluated in a peritoneal metastasis mouse model. As tumor cells were expected to predominate in the ascites of gastric cancer patients, the cellular composition was further characterized by flow cytometry, which unexpectedly revealed that immune cells constituted the major population. Furthermore, the selective cytotoxic activity of APNC against ascites-resistant immunosuppressive cells was evaluated in vitro.
We successfully generated CD8+ NKT like cells through ascites priming, which exhibited potent cytotoxicity and elevated cytokine production against gastric cancer cell lines and patient-derived ascites cells compared to CIK cells. Similar anti tumor efficacy was recapitulated in vivo using a peritoneal metastasis mouse model. Contrary to expectations, immunophenotypic analysis revealed that Tumor-Associated Macrophages (TAMs) and Myeloid-Derived Suppressor Cells (MDSCs), which serve as key drivers of immune suppression, constituted the dominant population in patient ascites, rather than tumor cells. Strikingly, APNC selectively targeted and eliminated these immunosuppressive cells, demonstrating the ability to dismantle the tumor-supportive microenvironment in vitro.
This study presents APNC as a novel ascites-primed NKT-like cell therapy tailored to the immunosuppressive microenvironment of gastric cancer peritoneal metastasis. APNC exhibited superior anti-tumor efficacy over CIK cells in vitro and in vivo, and uniquely targeted immunosuppressive TAMs and MDSCs. These findings underscore the translational potential of APNC as a next-generation cell therapy for advanced solid tumors.