While tumor-associated macrophages (TAMs) often have net pro-tumor effects, their embedded location and their untapped potential provide impetus to the discovery of strategies to turn them against tumors. We recently reported that a first in class selective class IIa HDAC inhibitor (TMP195) influenced human monocyte responses to colony stimulating factors CSF-1 and CSF-2 in vitro. Here, we utilize a macrophage-dependent autochthonous mouse model of breast cancer to demonstrate that in vivo TMP195 treatment alters the tumor microenvironment and reduces tumor burden and pulmonary metastases through macrophage modulation. TMP195 induces recruitment and differentiation of highly phagocytic and stimulatory macrophages within tumors. Furthermore, combining TMP195 with chemotherapy regimens or T-cell checkpoint blockade in this model significantly enhances the durability of tumor reduction. These data introduce class IIa HDAC inhibition as a novel means to harness the antitumor potential of macrophages to enhance cancer therapy.
Citation Format: Jennifer L. Guerriero, Alaba Sotayo, Holly Ponichtera, Alexandra Pourzia, Sara Schad, Ruben Carrasco, Suzan Lazo, Roderick Bronson, Anthony Letai. Class IIa HDAC inhibition promotes an antitumor macrophage phenotype that induces breast tumor regression and inhibits metastasis [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr B038.
- ©2016 American Association for Cancer Research.