Cytocompatibility, membrane disruption, and siRNA delivery using environmentally responsive cationic nanogels.

Advances in the formulation of nucleic acid-based therapeutics have rendered them a promising avenue for treating diverse ailments. Nonetheless, clinical translation of these therapies is hindered by a lack of strategies to ensure the delivery of these nucleic acids in a safe, efficacious manner with the required spatial and temporal control. To this aim, environmentally responsive hydrogels are of interest due to their ability to provide the desired characteristics of a protective carrier for siRNA delivery. Previous work in our laboratory has demonstrated the ability to synthesize nanoparticle formulations with targeted pKa, swelling, and surface PEG density. Here, a library of nanoparticle formulations was assessed on their in vitro toxicity, hemolytic capacity, siRNA loading, and gene-silencing efficacy. Successful candidates exhibited the lowest degrees of cytotoxicity, pH-dependent membrane disruption potential, the highest siRNA loading, and the highest transfection efficacies.

The Glutaminase Inhibitor CB-839 (Telaglenastat) Enhances the Antimelanoma Activity of T-Cell-Mediated Immunotherapies.

Immune-checkpoint inhibitors and adoptive tumor-infiltrating lymphocyte (TIL) therapies have profoundly improved the survival of patients with melanoma. However, a majority of patients do not respond to these agents, and many responders experience disease relapse. Although numerous innovative treatments are being explored to offset the limitations of these agents, novel therapeutic combinations with immunotherapies have the potential to improve patient responses. In this study, we evaluated the antimelanoma activity of immunotherapy combinations with Telaglenastat (CB-839), a potent glutaminase inhibitor (GLSi) that has favorable systemic tolerance. In in vitro TIL:tumor coculture studies, CB-839 treatment improved the cytotoxic activity of autologous TILs on patient-derived melanoma cells. CB-839 treatment decreased the conversion of glutamine to alpha-ketoglutarate (αKGA) more potently in tumor cells versus TILs in these cocultures. These results suggest that CB-839 may improve immune function in a tumor microenvironment by differentially altering tumor and immune cell metabolism. In vivo CB-839 treatment activated melanoma antigen-specific T cells and improved their tumor killing activity in an immune-competent mouse model of adoptive T-cell therapy. Additionally, the combination of CB-839 with anti-PD1 or anti-CTLA4 antibodies increased tumor infiltration by effector T cells and improved the antitumor activity of these checkpoint inhibitors in a high mutation burden mouse melanoma model. Responsiveness to these treatments was also accompanied by an increase of interferon gamma (IFNγ)-associated gene expression in the tumors. Together, these results provide a strong rationale for combining CB-839 with immune therapies to improve efficacy of these treatments against melanoma.