Project description:Virus-based cancer vaccines are nowadays considered an interesting approach in the field of cancer immunotherapy, despite the observation that the majority of the immune responses they elicit are against the virus and not against the tumor. In contrast, targeting tumor associated antigens is effective, however the identification of these antigens remains challenging. Here, we describe ExtraCRAd, a multi-vaccination strategy focused on an oncolytic virus artificially wrapped with tumor cancer membranes carrying tumor antigens. We demonstrate that ExtraCRAd displays increased infectivity and oncolytic effect in vitro and in vivo. We show that this nanoparticle platform controls the growth of aggressive melanoma and lung tumors in vivo both in preventive and therapeutic setting, creating a highly specific anti-cancer immune response. In conclusion, ExtraCRAd might serve as the next generation of personalized cancer vaccines with enhanced features over standard vaccination regimens, representing an alternative way to target cancer.
Project description:After a long period of endeavor, immunotherapy has become the mainstream of cancer therapies. This success is mostly ascribed to immune checkpoint blockade, chimeric antigen receptor-transduced T cell therapies, and bispecific antibodies. However, these methods have been effective or applicable to only a limited proportion of patients so far. Thus, further development of broadly applicable and effective immunotherapies is eagerly anticipated. Given that innate immunity is key to the induction of robust adaptive immunity and that the immunosuppressive tumor microenvironment is a major hurdle to overcome, intratumoral immunotherapy in which delivery of immunostimulatory microbial agents to the tumor site triggers innate immunity in situ is a rational strategy. There has been a plethora of preclinical and clinical trials conducted involving the delivery of either mimetics of viral nucleic acids or oncolytic viruses intratumorally to trigger innate immunity via various nucleic acid sensors in the tumor site. Many of these have shown significant antitumor effects in mice, particularly in combination with immune checkpoint blockade. Oncolytic herpes simplex virus type 1 has been approved for the treatment of advanced melanoma in the United States and Europe and of glioblastoma in Japan. Whereas direct intratumoral administration has mainly been chosen as a delivery route, several promising compounds amenable to systemic administration have been developed. Intratumoral delivery of immunostimulatory agents will become an important option for cancer immunotherapy as an off-the-shelf, broadly applicable, and rational strategy that exploits the physiology of immunity, namely anti-microbial immunity.
Project description:During chronic infections and cancer, T cells progressively lose function and become exhausted. However, effective T-cell responses are necessary to ultimately control viral infections and tumors. Hence, strategies that either restore endogenous immune responses or provide functional T cells by adoptive immunotherapy need to be explored. CD8 T cells play a prominent role in viral infections, as well as cancer, but CD4 T cells are necessary to support CD8 T-cell function. In addition, CD4 T cells exert direct effector functions, induce optimal B-cell responses and orchestrate innate immunity. Therefore, we propose that adoptive transfer strategies should exploit CD4 T cells alone or in combination with CD8 T cells, for the treatment of chronic infections and cancer. Furthermore, since adoptively transferred cells are subject to exhaustion, combining adoptive transfer therapy with immunotherapies that inhibit T-cell exhaustion should maximize the longevity and success rate of responses.
Project description:Cancer immunotherapy requires a specific antitumor CD8+ T cell-driven immune response; however, upon genetic and epigenetic alterations of the antigen processing and presenting components, cancer cells escape the CD8+ T cell recognition. As a result, poorly immunogenic tumors are refractory to conventional immunotherapy. In this context, the use of viral cancer vaccines in combination with hypomethylating agents represents a promising strategy to prevent cancer from escaping immune system recognition. In this study, we evaluated the sensitivity of melanoma (B16-expressing ovalbumin) and metastatic triple-negative breast cancer (4T1) cell lines to FDA-approved low-dose decitabine in combination with PeptiCRAd, an adenoviral anticancer vaccine. The two models showed different sensitivity to decitabine in vitro and in vivo when combined with PeptiCRAd. In particular, mice bearing syngeneic 4T1 cancer showed higher tumor growth control when receiving the combinatorial treatment compared to single controls in association with a higher expression of MHC class I on cancer cells and reduction in Tregs within the tumor microenvironment. Furthermore, remodeling of the CD8+ T cell infiltration and cytotoxic activity toward cancer cells confirmed the effect of decitabine in enhancing anticancer vaccines in immunotherapy regimens.
Project description:The remarkable specificity of the immune system through antigen recognition has long attracted investigators to the possibility of immune-based therapy for cancer. Previous cancer immunotherapeutics had been restricted to non-specific immunomodulatory agents, such as the cytokines IL-2 or IFN-α. However, the molecular definition of cancer-associated antigens introduced the possibility of specific vaccines and adoptive T cell approaches aiming to target the tumor cells more specifically. The recent introduction of total exome sequencing has enabled the identification of patient tumor-specific epitopes generated through somatic point mutations, raising the possibility of targeting tumor antigens in individual patients which are even more tumor-specific. Transcriptional profiling and immunohistochemistry analyses have revealed a subset of patients with a pre-existing T cell-inflamed tumor microenvironment. This phenotype may be predictive of clinical outcome to immunotherapies and offers the possibility of a predictive biomarker. Further analysis of these tumors has identified a set of defined immune suppressive factors which themselves are being targeted with new immunotherapeutics, already with interesting early phase clinical trial results. Understanding not only the expression of tumor antigens but also the dynamic between a growing tumor and the host immune response is thus generating a rich set of opportunities for the specific immunotherapy of cancer.
Project description:Protein-protein interactions involve hotspots as small as 4 sequential amino acids. Corresponding tetrapeptides have no structure in water. Here we report linking side chains of amino acids X and Z to form 24 cyclic tetrapeptides, cyclo-[XAAZ]-NH2, and stabilise 14-18 membered rings that mimic different kinds of non-regular secondary structures found in protein hotspots. 2D NMR spectra allowed determination of 3D structures for 14 cyclic tetrapeptides in water. Five formed two (i, i + 3) hydrogen bonds and a beta/gamma (6, 7) or beta (9, 19, 20) turn; eight formed one (i, i + 4) hydrogen bond and twisted into a non-helical (13, 18, 21, 22, 24) or helical (5, 17, 23) alpha turn; one was less structured (15). A beta or gamma turn was favoured for Z = Dab, Orn or Glu due to a χ1 gauche (+) rotamer, while an alpha turn was favoured for Z = Dap (but not X = Dap) due to a gauche (-) rotamer. Surprisingly, an unstructured peptide ARLARLARL could be twisted into a helix when either a helical or non-helical alpha turn (5, 13, 17, 18, 21-24) with Z = Dap was attached to the N-terminus. These structural models provide insights into stability for different turns and twists corresponding to non-regular folds in protein hotspots.
Project description:Immunotherapy holds tremendous potential in cancer therapy, in particular, when treatment regimens are combined to achieve synergy between pathways along the cancer immunity cycle. In previous works, we demonstrated that in situ vaccination with the plant virus cowpea mosaic virus (CPMV) activates and recruits innate immune cells, therefore reprogramming the immunosuppressive tumor microenvironment toward an immune-activated state, leading to potent anti-tumor immunity in tumor mouse models and canine patients. CPMV therapy also increases the expression of checkpoint regulators on effector T cells in the tumor microenvironment, such as PD-1/PD-L1, and we demonstrated that combination with immune checkpoint therapy improves therapeutic outcomes further. In the present work, we tested the hypothesis that CPMV could be combined with anti-PD-1 peptides to replace expensive antibody therapies. Specifically, we set out to test whether a multivalent display of anti-PD-1 peptides (SNTSESF) would enhance efficacy over a combination of CPMV and soluble peptide. Efficacy of the approaches were tested using a syngeneic mouse model of intraperitoneal ovarian cancer. CPMV combination with anti-PD-1 peptides (SNTSESF) resulted in increased efficacy; however, increased potency against metastatic ovarian cancer was only observed when SNTSESF was conjugated to CPMV, and not added as a free peptide. This can be explained by the differences in the in vivo fates of the nanoparticle formulation vs. the free peptide; the larger nanoparticles are expected to exhibit prolonged tumor residence and favorable intratumoral distribution. Our study provides new design principles for plant virus-based in situ vaccination strategies.