Abstract 3509: Targeting Spns2 induces immunogenic cell death and systemic anti-tumor immunity to suppress metastasis

Abstract 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 eIF2α 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. Citation Format: Han Gyul Lee, Wyatt Wofford, Alhaji H. Janneh, Paramita Chakarborty, Natalia Oleinik, Mohamed Faisal Kassir, Odai Darawshi, Neil Parikh, Stefano Berto, Kevin R. Lynch, Webster L. Santos, Özgür Şahin, Shikhar Mehrotra, Besim Ogretmen. Targeting Spns2 induces immunogenic cell death and systemic anti-tumor immunity to suppress metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3509.