Alan J Korman

TIGIT blockade enhances functionality of peritoneal NK cells with altered expression of DNAM-1/TIGIT/CD96 checkpoint molecules in ovarian cancer

Advanced ovarian cancer (OC) patients have a poor 5-year survival of only 28%, emphasizing the medical need for improved therapies. Adjuvant immunotherapy could be an attractive approach since OC is an immunogenic disease and the presence of tumor-infiltrating lymphocytes has shown to positively correlate with patient survival. Among these infiltrating lymphocytes are natural killer (NK) cells, key players involved in tumor targeting, initiated by signaling via activating and inhibitory receptors. Here, we investigated the role of the DNAM-1/TIGIT/CD96 axis in the anti-tumor response of NK cells toward OC. Ascites-derived NK cells from advanced OC patients showed lower expression of activating receptor DNAM-1 compared to healthy donor peripheral blood NK cells, while inhibitory receptor TIGIT and CD96 expression was equal or higher, respectively. This shift to a more inhibitory phenotype could also be induced

Myeloid Cells Orchestrate Systemic Immunosuppression, Impairing the Efficacy of Immunotherapy against HPV+ Cancers

Abstract Cancers induced by human papillomaviruses (HPV) should be responsive to immunotherapy by virtue of expressing the immunogenic oncoproteins E6/E7. However, advanced forms of cervical cancer, driven by HPV, are poorly responsive to immune response–enhancing treatments involving therapeutic vaccination against these viral neoantigens. Leveraging a transgenic mouse model of HPV-derived cancers, K14HPV16/H2b, we demonstrated that a potent nanoparticle-based E7 vaccine, but not a conventional “liquid” vaccine, induced E7 tumor antigen–specific CD8+ T cells in cervical tumor–bearing mice. Vaccination alone or in combination with anti-PD-1/anti-CTLA4 did not elicit tumor regression nor increase CD8+ T cells in the tumor microenvironment (TME), suggesting the presence of immune-suppressive barriers. Patients with cervical cancer have poor dendritic cell functions, have weak cytotoxic lymphocyte responses, and demonstrate an accumulation of myeloid cells in the periphery. Here, we illustrated that myeloid cells in K14HPV16/H2b mice possess potent immunosuppressive activity toward antigen-presenting cells and CD8+ T cells, dampening antitumor immunity. These immune-inhibitory effects inhibited synergistic effects of combining our oncoprotein vaccine with immune checkpoint–blocking antibodies. Our data highlighted a link between HPV-induced cancers, systemic amplification of myeloid cells, and the detrimental effects of myeloid cells on CD8+ T-cell activation and recruitment into the TME. These results established immunosuppressive myeloid cells in lymphoid organs as an HPV+ cancer–induced means of circumventing tumor immunity that will require targeted abrogation to enable the induction of efficacious antitumor immune responses.