Development of Tumor and Immuno-Metabolism Based Small Molecule Therapeutics for Refractory Breast Cancer Abstract Worldwide, approximately 1 million women are diagnosed with breast cancer each year. Triple Negative Breast Cancer (TNBC) is defined as that which does not express estrogen, progesterone, or Her-2 receptors. TNBC is the most deadly sub-type of breast cancer, accounting for ~15% of the breast cancer diagnoses and ~25% of breast cancer-related deaths. Median survival for 30% of the patients with TNBC is one year. TNBC has poor clinical outcomes due to its high metastatic rate, resistance to chemotherapy, and lack of effective treatment options. Although immunotherapy for cancers is rapidly expanding with the discovery of new targets and methods to activate immune function within tumors, it has only shown success in a limited subset of metastatic TNBC patients. The lactate-rich TNBC tumor microenvironment (TME) has been shown to be highly immunosuppressive, promoting tumor growth and progression. Cancer cells transport lactate across the cell membrane to the extracellular matrix via monocarboxylate transporters, MCT1 and MCT4. We have developed dual MCT1/4 inhibitors (dMCTi) to block lactate excretion to the TME thereby directly killing cancer cells and simultaneously activating local immunity in the TME. In our preliminary studies, we have shown that dMCTi are potent compounds against multiple TNBC cell lines. Also, we have shown that in in vivo experiments with both mouse xenograft models (MDA-MB-231, breast cancer) and syngeneic mouse models of melanoma and TNBC; SM1 (melanoma, BRAFV600E), and 4T1 (TNBC), dMCTi exert significant anti-tumor efficacy. Anti-tumor efficacy in MDA-MB-231 immune-deficient xenograft model shows inhibitors? direct cell killing effect. In the 4T1 and SM1 syngeneic models, we observed a decrease in expression of multiple immunosuppressive molecules such as B7 family proteins, macrophage polarization to M1, MDSCs, and increase in CD8+ population in treated tumors compared to the control tumors. Furthermore, profiling of cytokines indicated an increase in pro-inflammatory IFN?, TNF?, IL-1? and decrease in tumor promoting TGF?, IL-10 in treated tumors compared to the control tumors confirming that the anti-tumor effect of dMCTis is in part due to enhanced immune function. Supported by these preliminary data, we selected a dMCTi, NGY-B, as a pre-clinical development candidate. In this Direct Phase-II application, we propose to (1) conduct preclinical pharmacokinetic and safety studies of NGY-B, (2) Establish an effective dose regimen of NGY-B, investigate the efficacy of NGY-B in several mouse tumor models, and study the immune suppressive mechanisms in vivo, (3) establish NGY-B scalability for manufacturing, and request a pre-IND Type B meeting with FDA. Upon completion of these Aims, Nirogyone will have established NGY-B?s scalability, broader efficacy, and potential dose-limiting toxicities. We will then submit a SBIR Phase IIb grant application to evaluate non-GLP and GLP toxicology studies and assemble the IND package for first- in-human clinical trials.
Triple Negative Breast Cancer (TNBC) is defined by the receptor status of cancer cells. TNBC does not express estrogen, progesterone, or Her-2 receptors. TNBC is the most deadly sub- type of breast cancer, accounting for ~15% of breast cancer diagnoses and ~25% of breast cancer-related deaths. Median survival for 30% of the patients with TNBC is only one year. TNBC has poor clinical outcomes because it is highly metastatic, resistant to chemotherapy, and lacks targeted treatment options. TNBC cells are highly glycolytic, and therefore over- express monocarboxylate (lactate) transporters (MCTs) that are crucial for the cancer cells to adapt to glycolysis for their survival. In this proposal we outline the development of small molecule MCT1/4 dual inhibitors as a new therapeutic approach to effectively treat metastatic TNBC.
