Project description:The goal of therapeutic cancer vaccines and immune checkpoint therapy (ICT) is to eliminate cancer by expanding and/or sustaining T cells with anti-tumor capabilities. Here, we compared effective therapeutic tumor-specific mutant neoantigen (NeoAg) synthetic long peptide (SLP) cancer vaccines with anti-CTLA-4 and/or anti-PD-1 ICT in preclinical models. Effective NeoAg SLP vaccines and ICT required both CD8 and CD4 T cells. Both NeoAg SLP vaccines and ICT induce expansion of intratumoral NeoAg-specific CD8 T cells, though the degree of expansion and acquisition of effector activity was much more substantial following NeoAg SLP vaccination. Further, we found that NeoAg SLP vaccines are particularly adept at inducing proliferating and stem-like NeoAg-specific CD8 T cells. While NeoAg SLP vaccines and anti-PD-1 affected the CD4 T cell compartment, it was to less of an extent than observed with anti-CTLA-4, which notably induced ICOS+Bhlhe40+ Th1-like CD4 T cells. Although effective NeoAg SLP vaccines or ICT expanded intratumoral M1-like iNOS+ macrophages, NeoAg SLP vaccines maintained, rather than suppressed as observed with ICT, M2-like CX3CR1+CD206+ macrophages expressing the TREM2 receptor. While combining NeoAg SLP vaccination with ICT induced superior efficacy compared to either therapy in isolation, we also assessed a novel combination of NeoAg SLP vaccination and anti-TREM2, demonstrating enhanced efficacy of this combination associated with a decrease in intratumoral CX3CR1+CD206+ macrophages and promotion of IFN-g+ NeoAgspecific CD8 T cells. These findings highlight the utility of combining NeoAg SLP vaccines with ICT, as well as novel combinatorial therapy targeting the myeloid compartment via TREM2 blockade to enhance NeoAg SLP vaccine efficacy.
Project description:The goal of therapeutic cancer vaccines and immune checkpoint therapy (ICT) is to eliminate cancer by expanding and/or sustaining T cells with anti-tumor capabilities. Here, we compared effective therapeutic tumor-specific mutant neoantigen (NeoAg) synthetic long peptide (SLP) cancer vaccines with anti-CTLA-4 and/or anti-PD-1 ICT in preclinical models. Effective NeoAg SLP vaccines and ICT required both CD8 and CD4 T cells. Both NeoAg SLP vaccines and ICT induce expansion of intratumoral NeoAg-specific CD8 T cells, though the degree of expansion and acquisition of effector activity was much more substantial following NeoAg SLP vaccination. Further, we found that NeoAg SLP vaccines are particularly adept at inducing proliferating and stem-like NeoAg-specific CD8 T cells. While NeoAg SLP vaccines and anti-PD-1 affected the CD4 T cell compartment, it was to less of an extent than observed with anti-CTLA-4, which notably induced ICOS+Bhlhe40+ Th1-like CD4 T cells. Although effective NeoAg SLP vaccines or ICT expanded intratumoral M1-like iNOS+ macrophages, NeoAg SLP vaccines maintained, rather than suppressed as observed with ICT, M2-like CX3CR1+CD206+ macrophages expressing the TREM2 receptor. While combining NeoAg SLP vaccination with ICT induced superior efficacy compared to either therapy in isolation, we also assessed a novel combination of NeoAg SLP vaccination and anti-TREM2, demonstrating enhanced efficacy of this combination associated with a decrease in intratumoral CX3CR1+CD206+ macrophages and promotion of IFN-g+ NeoAgspecific CD8 T cells. These findings highlight the utility of combining NeoAg SLP vaccines with ICT, as well as novel combinatorial therapy targeting the myeloid compartment via TREM2 blockade to enhance NeoAg SLP vaccine efficacy.
Project description:Although irradiated induced-pluripotent stem cells (iPSCs) as a prophylactic cancer vaccine elicit an antitumor immune response, the therapeutic efficacy of iPSC-based cancer vaccines is not promising due to their insufficient antigenicity and the immunosuppressive tumor microenvironment. Here, we found that neoantigen-engineered iPSC cancer vaccines can trigger neoantigen-specific T cell responses to eradicate cancer cells and increase the therapeutic efficacy of RT in poorly immunogenic colorectal cancer (CRC) and triple-negative breast cancer (TNBC). We generated neoantigen-augmented iPSCs (NA-iPSCs) by engineering AAV2 vector carrying murine neoantigens and evaluated their therapeutic efficacy in combination with radiotherapy. After administration of NA-iPSC cancer vaccine and radiotherapy, we found that ~60% of tumor-bearing mice achieved a complete response in microsatellite-stable CRC model. Furthermore, splenocytes from mice treated with NA-iPSC plus RT produced high levels of IFN secretion in response to neoantigens and had a greater cytotoxicity to cancer cells, suggesting that the NA-iPSC vaccine combined with radiotherapy elicited a superior neoantigen-specific T-cell response to eradicate cancer cells. The superior therapeutic efficacy of NA-iPSCs engineered by mouse TNBC neoantigens was also observed in the syngeneic immunocompetent TNBC mouse model. We found that the risk of spontaneous lung and liver metastasis was dramatically decreased by NA-iPSCs plus RT in the TNBC animal model. Altogether, these results indicated that autologous iPSC cancer vaccines engineered by neoantigens can elicit a high neoantigen-specific T-cell response, promote tumor regression and reduce the risk of distant metastasis in combination with local radiotherapy.
Project description:Neoantigen-based cancer vaccines designed to target the unique immunogenic mutations arising in each patient's tumor are breathing new life into a struggling approach. Data continue to demonstrate the importance of neoantigens in immune control of cancer. Despite manufacturing complexity, outstanding questions and desired further improvements, neoantigen vaccines are currently undergoing clinical evaluation.
Project description:Neoantigens are promising immunogens for cancer vaccines and are traditionally delivered as adjuvanted peptide vaccines. Our goal was to understand how an adenoviral vectored neoantigen vaccine would induce tumor immunity compared to a peptide neoantigen vaccine. We generated adenovirus serotype 26 (Ad26) vaccines encoding MC38-specific neoantigens and compared them to an adjuvanted peptide MC38 neoantigen vaccine. The single-shot Ad26 vaccines induced greater neoantigen specific IFN- CD8+ T cell immune responses than the two-shot adjuvanted peptide vaccine in mice, and Ad26.VP22.7Epi also provided superior protective efficacy compared to the peptide vaccine following tumor challenge. Ad26.VP22.7Epi induced a robust immunodominant CD8+ T cell response against the Adpgk neoantigen, while the peptide vaccine induced lower responses against both Adpgk and Reps1 neoantigens. Tumor infiltrating lymphocytes (TILs) from both vaccine groups were analyzed using scRNA-seq and TCR-seq. Vaccinated mice showed increased CD8+ T cell infiltration, with the peptide vaccine inducing more infiltrating CD8+ T cells than the Ad26.VP22.7Epi vaccine. However, Ad26.VP22.7Epi induced CD8+ T cells showed more upregulation of T cell maturation, activation, and Th1 pathways compared to peptide vaccine induced CD8+ T cells, suggesting improved functional T cell quality. TCR-seq of these TILs also demonstrated that Ad26.VP22.7Epi generated larger T cell hyperexpanded clones compared to the peptide vaccine. These results suggest that the Ad26.VP22.7Epi vaccine led to improved tumor control compared with the peptide vaccine due to increased T cell hyperexpansion and functional activation. Our data suggest that future cancer vaccine development strategies should focus on inducing functional hyperexpanded CD8+ T cell responses and not only maximizing tumor infiltrating CD8+ T cell numbers.
Project description:Optimized polyepitope neoantigen DNA vaccines elicit neoantigen-specific immune responses in preclinical models and in clinical translation
Project description:Optimized polyepitope neoantigen DNA vaccines elicit neoantigen-specific immune responses in preclinical models and in clinical translation
Project description:The purpose of this study is 1) to evaluate the feasibility of manufacturing a patient-specific neoantigen cancer vaccine, which involves predicting the patient’s neoantigens and generating a vaccine that encodes the predicted neoantigens; and, 2) to identify and select patients who may be eligible for a shared neoantigen cancer vaccine where their tumor contains a specific shared mutation and who have the correct HLA allele capable of presenting the neoantigen derived from the tumor-specific mutation.