Background: TGF-Β (transforming growth factor-beta) is an essential cytokine for tumor proliferation and metastasis. The expression of TGF-Β correlates with malignancy of various cancers and involves immunosuppression and angiogenesis of a tumor. IL-2 is a major cytokine to proliferate T cells and NK cells which are major players of cancer immunity. However, the toxicity of high dose IL-2 limits its use in cancer therapy. Combination treatment of TGF-Β inhibitor and IL-2 would have an anti-tumor effect by immune cells through diminishing immunosuppression by TGF-Β and enforcement of immune cells by IL-2. Trabedersen is an anti-sense oligonucleotide targeting human TGF-Β mRNA. It is shown that Trabedersen is well tolerable in cancer patients and effective reagent to treat pancreatic cancer, melanoma, and glioblastoma. Proleukin is the only approved IL-2 reagent to treat Renal cell carcinoma and Melanoma.

Methods: Trabedersen and Proleukin activated human PBMC (Peripheral Blood Mononuclear Cell) are treated to several solid cancer cell lines, such as Breast cancer, Pancreatic cancer, Melanoma, Lung cancer, and Colon cancer to see the cytotoxicity effect of combination therapy of Trabedersen and Proleukin. NSG mouse (NOD Scid Gamma mouse, NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) which are humanized by human PBMC engraftment and the tumor growth of Melanoma and TNBC (Triple Negative Breast Cancer cell) cell line are monitored.

Results: The combination treatment of Trabedersen and low dose Proleukin decreased cancer cell viability in vitro experiment in solid cancer cell lines. Melanoma and TNBC tumor growth was delayed in humanized NSG mouse model by Trabedersen and low dose IL-2 combination therapy and tumor growth delay was statistically significant to Trabedersen alone or IL-2 alone group. Tumor infiltrating lymphocyte population was increased in Trabedersen treated group and FoxP3+ regulatory T cell population in blood and tumor microenvironment was decreased by treatment of Trabedersen.

Conclusion: TGF-Β inhibitor (Trabedersen) and low dose IL-2 (Proleukin) combination treatment is expected to be an effective regimen in solid cancer treatment than individual treatment by alteration of tumor environment. Modulation of the dose of Proleukin expects to help reduce the toxicity of IL-2 and increase the anti-cancer effect by combination with Trabedersen.

Citation Format: Jun-Eui Park, Jihye Koo, Hong-Kyu Lee, Tae Hun Kim. Combination therapy of anti-sense oligonucleotide targeting TGF-beta2 (TASO) and IL-2 (Proleukin) has anti-cancer effect in solid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1448.