Antitumor activity of epigenetic immunomodulation combined with CTLA-4 blockade in syngeneic mouse models.

The multifaceted immunomodulatory activity of DNA hypomethylating agents improves immunogenicity and immune recognition of neoplastic cells; thus, we predicted they could be utilized to design new immunotherapeutic combinations in cancer. Testing this hypothesis, the antitumor efficacy of the DNA hypomethylating agent 5-aza-2'-deoxycytidine (5-AZA-CdR) combined with the anti-CTLA-4 monoclonal antibody (mAb) 9H10 in syngeneic transplantable murine models was investigated. Murine mammary carcinoma TS/A or mesothelioma AB1 cells were injected in BALB/c, athymic nude, and SCID/Beige mice that were treated with 5-AZA-CdR, mAb 9H10, or their combination.

Immunomodulatory activity of SGI-110, a 5-aza-2'-deoxycytidine-containing demethylating dinucleotide.

Purpose: Pharmacologic DNA hypomethylation holds strong promises in cancer immunotherapy due to its immunomodulatory activity on neoplastic cells. Searching for more efficient DNA hypomethylating agents to be utilized to design novel immunotherapeutic strategies in cancer, we investigated the immunomodulatory properties of the new DNA hypomethylating agent SGI-110, that is resistant to in vivo inactivation by cytidine deaminase.

Experimental Design: Cutaneous melanoma, mesothelioma, renal cell carcinoma, and sarcoma cells were treated in vitro with SGI-110.