Cell-based immunotherapy is rapidly emerging as a promising alternative to conventional chemotherapy-based treatment for cancer. Previous studies have shown that high salt treatment induces naive CD4+T lymphocytes to differentiate into a highly proinflammatory Th17 phenotype. In our current study, we analyzed the ability of salt treatment to induce cancer-specific Th17 lymphocytes. Naive CD4+T cells isolated by immunomagnetic bead isolation from splenocytes of 10-week-old BALB/c mice were treated in vitro with high salt (Δ0.05 M NaCl) along with CD3 monoclonal antibodies (mAbs), CD28 mAbs and IL-2 for 4 days along with heat killed 4T1 breast cancer cells. The isolated CD4+CCR6+CD45RA-CXCR3- cells were tested for IL-17 expression by flow cytometry and determined to be >95% pure. Orthotopic murine breast tumor models established by injection of 4T1 cells into the mammary fat pad of Nu/J mice were administered two doses of (1 × 106) salt induced Th17 cells on day 7 and day 12, post-tumor implantation. By day 28, the high salt induced Th17 cells cohort demonstrated significantly reduced tumor growth (97 ± 34 mm3 vs 512 ± 91 mm3, untreated control, p<0.05) and lung metastasis. However, no effect on tumor growth was noted when these 4T1 sensitized high salt treated Th17 cells were injected into Nu/J mice with prostrate (RM1) and lung tumors (KLN205), thus suggesting that the specificity of salt induced Th17 cells to breast tumors. Similarly, in vitro high salt mediated differentiation of Th17 cells when co-treated with heat killed RM1 and KLN205 cancer cells were able to induce respective murine tumor regression. Mechanistic studies demonstrated that the high salt induction to the Th17 phenotype was mediated by the tonicity-dependent transcription factor, TonEBP/NFAT5. The shRNA-based knockdown of TonEBP abrogated the induction of the Th17 phenotype and expression of proinflammatory cytokines IL-17, IL-1β and IL-6. Taken together, our data suggests that high salt mediated in vitro differentiation of Th17 cells could induce tumor specific anticancer CD4+T lymphocytes, which may give rise to a cell-based anticancer immunotherapy application.

Citation Format: Suneetha Amara, Pooja Yenuga, Roy Zent, Venkataswarup Tiriveedhi. NFAT5/TonEBP mediated anti-tumor efficiency of high salt activated CD4+T lymphocytes [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B45.