Targeting Spns2 induces immunogenic cell death and systemic anti-tumor immunity to suppress metastasis

Background: Spinster homolog 2 (SPNS2) exports sphingosine-1-phosphate (S1P) to promote oncogenic signaling. Although SPNS2 is associated with metastatic progression, its tumor-intrinsic role in regulating immunogenic cell death (ICD) and anti-tumor immunity remains unclear. We examined how genetic or pharmacologic inhibition of SPNS2 influences metastasis, ICD induction, and systemic immune activation. Methods: Patient datasets were analyzed in conjunction with breast (4T1, EMT6) and melanoma (B16) models. SPNS2 was ablated using CRISPR or inhibited using a first-in-class small-molecule SPNS2 inhibitor. S1P export, migration, and S1PR1-AKT signaling were assessed in vitro. Orthotopic, tail-vein, co-injection, and vaccination models were used to evaluate tumor growth, metastatic spread, ICD signatures, and systemic immunity. Individual DAMP pathways were disrupted to test mechanistic requirements. Results: High SPNS2 expression correlated with poor survival across multiple cancer types. SPNS2 promoted S1P export, S1PR1-AKT activation, epithelial-mesenchymal transition, stemness, and lung colonization, whereas SPNS2 loss impaired migration and markedly reduced spontaneous and experimental metastases. SPNS2 inhibition elicited hallmark ICD features-including eIF2alpha phosphorylation, calreticulin exposure, and ATP/HMGB1 release-enhancing antigen presentation, expanding CD4⁺ and CD8⁺ T cells, and limiting primary tumor growth, metastasis, and postsurgical relapse. Vaccination with SPNS2-deficient or inhibitor-treated tumor cells protected against rechallenge with 4T1 or antigenically distinct EMT6 tumors. Disruption of individual DAMP pathways attenuated these responses, demonstrating ICD dependence. Conclusions: SPNS2-mediated S1P transport drives metastasis and immune evasion, whereas SPNS2 inhibition induces ICD and potent systemic T-cell immunity. Targeting SPNS2 represents a therapeutic strategy to suppress metastatic progression and generate durable anti-tumor immunity. Disclosure: Generative AI was used to assist in editing this abstract.