Approach For Cancer Immunotherapy Research Articles

Uniform Polymeric Nanovaccine Platform for Improving the Availability and Efficacy of Neoantigen Peptides.

Personalized cancer vaccines targeting specific neoantigens have been envisioned as one of the most promising approaches in cancer immunotherapy. However, the physicochemical variability of the identified neoantigens limits their efficacy as well as vaccine manufacturing in a uniform format. Herein, we developed a uniform nanovaccine platform based on poly(2-oxazoline)s (POx) to chemically conjugate neoantigen peptides, regardless of their physicochemical properties. This vaccine system could self-assemble into nanoparticles with uniform size (around 50 nm) and improve antigen accumulation as well as infiltration in the lymph node to increase antigen presentation. In vivo vaccination using this system conjugated with three predicted peptide neoantigen peptides from the MC38 tumor cell line induced 100% robust CD8+ T cell responses and superior tumor clearance compared to free peptides. This POx-based vaccine carrier represents a generalizable approach to increase the availability and efficacy of screened neoantigen peptides for a personalized cancer vaccine.

Current Trends and Innovative Approaches in Cancer Immunotherapy.

Immunotherapy is one of the most promising therapeutic approaches in the field of cancer treatment. As a tumor progresses, tumor cells employ an array of immune-regulatory mechanisms to suppress immune responses within the tumor microenvironment. Using our understanding of these mechanisms, cancer immunotherapy has been developed to enhance the immune system's effectiveness in treating cancer. Numerous cancer immunotherapies are currently in clinical use, yet many others are either in different stages of development or undergoing clinical studies. In this paper, we briefly discuss the features and current status of cancer immunotherapies. This includes the application of monoclonal antibodies, immune checkpoint inhibitors, adoptive cell therapy, cytokine therapy, cancer vaccines, and gene therapy, all of which have gained significant recognition in clinical practice. Additionally, we discuss limitations that may hinder successful clinical utilization and promising strategies, such as combining immunotherapy with nanotechnology.

Orchestrating NK and T cells via tri-specific nano-antibodies for synergistic antitumor immunity

The functions of natural killer (NK) and T cells in innate and adaptive immunity, as well as their functions in tumor eradication, are complementary and intertwined. Here we show that utilization of multi-specific antibodies or nano-antibodies capable of simultaneously targeting both NK and T cells could be a valuable approach in cancer immunotherapy. Here, we introduce a tri-specific Nano-Antibody (Tri-NAb), generated by immobilizing three types of monoclonal antibodies (mAbs), using an optimized albumin/polyester composite nanoparticle conjugated with anti-Fc antibody. This Tri-NAb, targeting PDL1, 4-1BB, and NKG2A (or TIGIT) simultaneously, effectively binds to NK and CD8+ T cells, triggering their activation and proliferation, while facilitating their interaction with tumor cells, thereby inducing efficient tumor killing. Importantly, the antitumor efficacy of Tri-NAb is validated in multiple models, including patient-derived tumor organoids and humanized mice, highlighting the translational potential of NK and T cell co-targeting.

Dual-Responsive Epigenetic Inhibitor Nanoprodrug Combined with Oncolytic Virus Synergistically Boost Cancer Immunotherapy by Igniting Gasdermin E-Mediated Pyroptosis.

Cancer immunotherapy has emerged as a promising approach for the treatment of various cancers. However, the immunosuppressive tumor microenvironment (TME) limits the efficacy of current immunotherapies. In this study, we designed a dual-responsive DNA methyltransferase inhibitor nanoprodrug ACNPs for combination therapy with oncolytic herpes simplex virus (oHSV). We found that the epigenetic inhibitor 5-Azacytidine (5-Aza) upregulated gasdermin E (GSDME) expression at the gene level, whereas the oHSV decreased the ubiquitination and degradation of GSDME to elevate its levels. Based on these observations, we further discovered that ACNPs and oHSV synergistically enhanced GSDME-mediated pyroptosis. Additionally, the combination therapy of ACNPs and oHSV effectively inhibited tumor growth, remodeled the immunosuppressive TME, and improved the efficacy of immune checkpoint blockade (ICB) therapy. These results demonstrate the potential to overcome immunosuppression through synergistic combinations, offering a promising approach for cancer immunotherapy.

A combined radio-immunotherapy regimen eradicates late-stage tumors in mice.

The majority of experimental approaches for cancer immunotherapy are tested against relatively small tumors in tumor-bearing mice, because in most cases advanced cancers are resistant to the treatments. In this study, we asked if even late-stage mouse tumors can be eradicated by a rationally designed combined radio-immunotherapy (CRI) regimen. CRI consisted of local radiotherapy, intratumoral IL-12, slow-release systemic IL-2 and anti- CTLA-4 antibody. Therapeutic effects of CRI against several weakly immunogenic and immunogenic mouse tumors including B78 melanoma, MC38 and CT26 colon carcinomas and 9464D neuroblastoma were evaluated. Immune cell depletion and flow cytometric analysis were performed to determine the mechanisms of the antitumor effects. Tumors with volumes of 2,000 mm3 or larger were eradicated by CRI. Flow analyses of the tumors revealed reduction of T regulatory (Treg) cells and increase of CD8/Treg ratios following CRI. Rapid shrinkage of the treated tumors did not require T cells, whereas T cells were involved in the systemic effect against the distant tumors. Cured mice developed immunological memory. These findings underscore that rationally designed combination immunotherapy regimens can be effective even against large, late-stage tumors.

Hydrogel activation of Mincle receptors for tumor cell processing: A novel approach in cancer immunotherapy

An obstacle in current tumor immunotherapies lies in the challenge of achieving sustained and tumor-targeting T cell immunity, impeded by the limited antigen processing and cross-presentation of tumor antigens. Here, we propose a hydrogel-based multicellular immune factory within the body that autonomously converts tumor cells into an antitumor vaccine. Within the body, the scaffold, formed by a calcium-containing chitosan hydrogel complex (ChitoCa) entraps tumor cells and attracts immune cells to establish a durable and multicellular microenvironment. Within this context, tumor cells are completely eliminated by antigen-presenting cells (APCs) and processed for cross-antigen presentation. The regulatory mechanism relies on the Mincle receptor, a cell-phagocytosis-inducing C-type lectin receptor specifically activated on ChitoCa-recruited APCs, which serves as a recognition synapse, facilitating a tenfold increase in tumor cell engulfment and subsequent elimination. The ChitoCa-induced tumor cell processing further promotes the cross-presentation of tumor antigens to prime protective CD8+ T cell responses. Therefore, the ChitoCa treatment establishes an immune niche within the tumor microenvironment, resulting in effective tumor regression either used alone or in combination with other immunotherapies. This hydrogel-induced immune factory establishes a functional organ-like multicellular colony for tumor-specific immunotherapy, paving the way for innovative strategies in cancer treatment.

Pan-cancer analysis of T-cell proliferation regulatory genes as potential immunotherapeutic targets.

T cells are the key to killing tumor cells. However, the exact mechanism of their role in cancer is not fully understood. Therefore, a comprehensive understanding of the role of T-cell proliferation regulatory genes in tumors is needed. In our study, we investigated the expression levels of genes controlling T-cell proliferation, their impact on prognosis, and their genetic variations. Additionally, we explored their associations with TMB, MSI, ESTIMATEScore, ImmuneScore, StromalScore, and immune cell infiltration. We examined the role of these genes in cancer-related pathways using GSEA. Furthermore, we calculated their activity levels across various types of cancer. Drug analysis was also conducted targeting these genes. Single-cell analysis, LASSO Cox model construction, and prognosis analysis were performed. We observed distinct expression patterns of T-cell proliferation regulatory genes across different malignant tumors. Their abnormal expression may be caused by CNA and DNA methylation. In certain cancers, they also showed complex associations with TMB and MSI. Moreover, in many tumors, they exhibited significant positive correlations with ESTIMATEScores, ImmuneScore, and StromalScore. Additionally, in most tumors, their GSVA scores were significantly positively correlated with various T-cell subtypes. GSEA analysis revealed their involvement in multiple immune pathways. Furthermore, we found that model scores were associated with patient prognosis and related to tumor malignancy progression. T-cell proliferation regulatory genes are closely associated with the tumor immune microenvironment (TIM), especially T cells. Targeting them may be an essential approach for cancer immunotherapy.

Robust anti-tumor immunity through the integration of targeted lipid nanoparticle-based mRNA nanovaccines with PD-1/PD-L1 blockade

Tumor mRNA vaccines present a personalized approach in cancer immunotherapy, encoding distinct tumor antigens to evoke robust immune responses and offering the potential against emerging tumor variants. Despite this, the clinical advancement of tumor mRNA vaccines has been hampered by their limited delivery capacity and inefficient activation of antigen-presenting cells (APCs). Herein, we employed microfluidics technology to engineer mannose-modified lipid-based nanovaccines for specifically targeting APCs. The encapsulation process efficiently entrapped the cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) agonist along with mRNA encoding antigens. The targeted nanovaccines (TNVs) exhibited a narrow particle size distribution, ensuring consistent and efficient delivery. These TNVs significantly enhanced gene expression of mRNA, facilitating antigen presentation and immune activation. When compared to non-targeted nanovaccines, TNVs outperformed in terms of antigen presentation and immune activation. Furthermore, the combination of anti-PD-L1 antibodies with TNVs elicited a synergistic anti-tumor effect. This was attributed to the anti-PD-L1 antibodies' ability to overcome the immune suppression of tumor cells. Our findings suggest that the combination treatment elicited the most robust anti-tumor immune activation and immune memory effect. These results indicate that integrating tumor mRNA vaccines with immune checkpoint inhibitors or other immunostimulatory agents may be crucial for enhancing the immune response.

Combination of STING agonist with anti-vascular RGD-(KLAKLAK)2 peptide as a novel anti-tumor therapy

Immunotherapy is one of the most promising anti-cancer treatment. It involves activating the host's own immune system to eliminate cancer cells. Activation of cGAS-STING pathway is promising therapeutic approach for cancer immunotherapy. However, in human clinical trials, targeting cGAS-STING pathway results in insufficient or unsustainable anti-tumor response. To enhance its effectiveness, combination with other anti-cancer therapies seems essential to achieve synergistic systemic anti-tumor response.The aim of this study was to evaluate whether the combination of STING agonist-cGAMP with anti-vascular RGD-(KLAKLAK)2 peptide results in a better anti-tumor response in poorly immunogenic tumors with various STING protein and αvβ3 integrin status.Combination therapy inhibited growth of murine breast carcinoma more effectively than melanoma. In melanoma, the administration of STING agonist alone was sufficient to obtain a satisfactory therapeutic effect. In both tumor models we have noted stimulation of innate immune response following cGAMP administration alone or in combination. The largest population of immune cells infiltrating the TME after therapy were activated NK cells. Increased infiltration of cytotoxic CD8+ T lymphocytes within the TME was only observed in melanoma tumors. However, they also expressed the “exhaustion” PD-1 receptor. In contrast, in breast carcinoma tumors each therapy caused the drop in the number of infiltrating CD8+ T cells.The obtained results indicate an additional therapeutic benefit from combining STING agonist with an anti-vascular agent. However, this effect depends on the type of tumor, the status of its microenvironment and the expression of specific proteins such as STING and αvβ3 family integrin.

STAT signaling pathways in immune cells and their associated mechanisms in cancer pathogenesis

Introduction: Signal transducer and activator of transcriptions (STATs) factors as critical proteins in cell signaling regulate diverse biological processes such as differentiation and proliferation of cells. STATs have been shown to play distinct roles in modulating immune responses mediated by innate and adaptive immune cell subsets due to their significant roles in cytokine signaling. Methods: In the current study, we review recent studies on the contribution of individual STAT proteins to cytokine signaling, development, and activity of diverse immune cells that constitute the whole immune system and help its performance against endogenous or exogenous agents with a particular focus on meaningful STAT factor in each of innate and adaptive immune cells’ subsets to clarify their function in favor of the tumor or against it. Results: Dysregulation of signaling pathways in the immune cells is associated with various immune disorders, such as the inability of immune system cells in the effective destruction of cancerous cells. Increase of knowledge about these pathways’ functions is essential to understand how they can be effectively targeted to eliminate tumors. Conclusion: The majority of immune cells use the Jak/STAT signaling pathway, which is one of the most important signaling pathways with a role in induction of proper immune responses. Since each of the STAT factors has a specific role in diverse immune cells’ subsets, appropriate targeting of them can be a promising strategy for patients who suffer from immune system disorders; specifically it can be beneficial as an approach for cancer immunotherapy.

Genetically Engineered CLDN18.2 CAR-T Cells Expressing Synthetic PD1/CD28 Fusion Receptors Produced Using a Lentiviral Vector.

This study aimed to develop synthetic Claudin18.2 (CLDN18.2) chimeric antigen receptor (CAR)-T (CAR-T) cells as a treatment for advanced gastric cancer using lentiviral vector genetic engineering technology that targets the CLDN18.2 antigen and simultaneously overcomes the immunosuppressive environment caused by programmed cell death protein 1 (PD-1). Synthetic CAR T cells are a promising approach in cancer immunotherapy but face many challenges in solid tumors. One of the major problems is immunosuppression caused by PD-1. CLDN18.2, a gastric-specific membrane protein, is considered a potential therapeutic target for gastric and other cancers. In our study, CLDN18.2 CAR was a second-generation CAR with inducible T-cell costimulatory (CD278), and CLDN18.2-PD1/CD28 CAR was a third-generation CAR, wherein the synthetic PD1/CD28 chimeric-switch receptor (CSR) was added to the second-generation CAR. In vitro, we detected the secretion levels of different cytokines and the killing ability of CAR-T cells. We found that the secretion of cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) secreted by three types of CAR-T cells was increased, and the killing ability against CLDN18.2-positive GC cells was enhanced. In vivo, we established a xenograft GC model and observed the antitumor effects and off-target toxicity of CAR-T cells. These results support that synthetic anti-CLDN18.2 CAR-T cells have antitumor effect and anti-CLDN18.2-PD1/CD28 CAR could provide a promising design strategy to improve the efficacy of CAR-T cells in advanced gastric cancer.

Regulation of sialic acid metabolism in cancer

Sialic acid, the terminal structure of cell surface glycans, has essential functions in regulating immune response, cell-to-cell communication, and cell adhesion. More importantly, an increased level of sialic acid, termed hypersialylation, has emerged as a commonly observed phenotype in cancer. Therefore, targeting sialic acid ligands (sialoglycans) and their receptors (Siglecs) may provide a new therapeutic approach for cancer immunotherapy. We highlight the complexity of the sialic acid metabolism and its involvement in malignant transformation within individual cancer subtypes. In this review, we focus on the dysregulation of sialylation, the intricate nature of sialic acid synthesis, and clinical perspective. We aim to provide a brief insight into the mechanism of hypersialylation and how our understanding of these processes can be leveraged for the development of novel therapeutics.

Discovery of 4-phenyl-1H-indazole derivatives as novel small-molecule inhibitors targeting the PD-1/PD-L1 interaction

The inhibition of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway with small molecules is a promising approach for cancer immunotherapy. Herein, novel small molecules compounds bearing various scaffolds including thiophene, thiazole, tetrahydroquinoline, benzimidazole and indazole were designed, synthesized and evaluated for their inhibitory activity against the PD-1/PD-L1 interaction. Among them, compound Z13 exhibited the most potent activity with IC50 of 189.6 nM in the homogeneous time-resolved fluorescence (HTRF) binding assay. Surface plasmon resonance (SPR) assay demonstrated that Z13 bound to PD-L1 with high affinity (KD values of 231 nM and 311 nM for hPD-L1 and mPD-L1, respectively). In the HepG2/Jurkat T co-culture cell model, Z13 decreased the viability rate of HepG2 cells in a concentration-dependent manner. In addition, Z13 showed significant in vivo antitumor efficacy (TGI = 52.6 % at 40 mg/kg) without obvious toxicity in the B16-F10 melanoma model. Furthermore, flow cytometry analysis demonstrated that Z13 inhibited tumor growth in vivo by activating the tumor immune microenvironment. These findings indicate that Z13 is a promising PD-1/PD-L1 inhibitor deserving further investigation.

A novel bispecific antibody drug conjugate targeting HER2 and HER3 with potent therapeutic efficacy against breast cancer.

Antibody drug conjugate (ADC) therapy has become one of the most promising approaches in cancer immunotherapy. Bispecific targeting could enhance the efficacy and safety of ADC by improving its specificity, affinity and internalization. In this study we constructed a HER2/HER3-targeting bispecific ADC (BsADC) and characterized its physiochemical properties, target specificity and internalization in vitro, and assessed its anti-tumor activities in breast cancer cell lines and in animal models. The HER2/HER3-targeting BsADC had a drug to antibody ratio (DAR) of 2.89, displayed a high selectivity against the target JIMT-1 breast cancer cells in vitro, as well as a slightly higher level of internalization than HER2- or HER3-monospecific ADCs. More importantly, the bispecific ADC potently inhibited the viability of MCF7, JIMT-1, BT474, BxPC-3 and SKOV-3 cancer cells in vitro. In JIMT-1 breast cancer xenograft mice, a single injection of bispecific ADC (3 mg/kg, i.v.) significantly inhibited the tumor growth with an efficacy comparable to that caused by combined injection of HER2 and HER3-monospecific ADCs (3 mg/kg for each). Our study demonstrates that the bispecific ADC concept can be applied to development of more potent new cancer therapeutics than the monospecific ADCs.

Engineered Luminescent Oncolytic Vaccinia Virus Activation of Photodynamic-Immune Combination Therapy for Colorectal Cancer.

Oncolytic virus therapy is currently regarded as a promising approach in cancer immunotherapy. It has greater therapeutic advantages for colorectal cancer that is prone to distant metastasis. However, the therapeutic efficacy and clinical application of viral agents alone for colorectal cancer remain suboptimal. In this study, an engineered oncolytic vaccinia virus (OVV-Luc) that expresses the firefly luciferase gene is developed and loaded Chlorin e6 (Ce6) onto the virus surface through covalent coupling, resulting in OVV-Luc@Ce6 (OV@C). The OV@C infiltrates tumor tissue and induces endogenous luminescence through substrate catalysis, resulting in the production of reactive oxygen species. This unique system eliminates the need for an external light source, making it suitable for photodynamic therapy (PDT) in deep tissues. Moreover, this synergistic effect between PDT and viral immunotherapy enhances dendritic cell maturation, macrophage polarization, and reversal of the immunosuppressive microenvironment. This synergistic effect has the potential to convert a "cold" into a "hot" tumor, it offers valuable insights for clinical translation and application.

Abstract LB237: PVRL2 suppresses antitumor immune responses through PVRIG- and TIGIT-independent pathways

Abstract In recent years, PVRL2 (also known as Nectin-2 or CD112), a member of the Nectin family, has emerged as a crucial regulator of anti-tumor immune responses. PVRL2 interacts with the co-inhibitory receptor PVRIG that is expressed on T cells and NK cells, inhibiting their function. This interaction has thus become the presumed mechanism for PVRL2’s immunoinhibitory function. Therapeutic development targeting the PVRL2 pathway has primarily focused on the receptor PVRIG, with two anti-PVRIG antibodies currently undergoing Phase 1/2 clinical trials (NCT03667716, NCT04570839, NCT05746897). However, to date, very few studies have directly investigated the role of PVRL2, and whether PVRL2 indeed acts through PVRIG hasn’t been formally tested. Our recent work reveals the crucial role of PVRL2 in suppressing anti-tumor immune responses across multiple syngeneic mouse models. CRISPR-directed deletion of PVRL2 robustly reduced tumor growth in an immune-dependent manner, with an even greater effect than seen with the deletion of the prominent checkpoint, PD-L1. Specifically, our findings suggest that PVRL2 functions by suppressing CD8 T and NK cells in the tumor microenvironment. Interestingly, the impact of PVRL2 on tumor growth in our study is certainly much more significant than observed in previous work on PVRIG. To follow up on this interesting finding and determine whether the PVRL2’s impact on immune cells acts through PVRIG, we generated Pvrig KO mice. Surprisingly, we found that PVRL2’s function is largely independent of PVRIG, as it still robustly promotes tumor growth even in the absence of PVRIG, indicating PVRIG-independent mechanisms. We further demonstrate that PVRL2 operates in parallel to the PVR-TIGIT pathway, another important immunoregulatory pathway in the Nectin family. Combined deletion of PVR or PVRIG with PVRL2 loss did not further suppress tumor growth, while combined TIGIT blockade with PVRL2 loss resulted in the most substantial reduction in tumor growth. These findings strongly indicate the existence of additional unknown receptors mediating PVRL2’s function that remain to be discovered. Importantly, our study uncovers PVRL2’s central role in suppressing anti-tumor immune responses through mechanism outside its presumed receptor PVRIG, providing a compelling rationale for directly targeting PVRL2 itself. Combining PVRL2 and TIGIT targeting results in a near-complete block in tumor growth, offering a novel and promising therapeutic approach for cancer immunotherapy through the combinatorial targeting of PVRL2 and TIGIT. Citation Format: Jiuling Yang, Li Wang, James Byrnes, Lisa Kirkemo, Hannah Driks, Cassandra Belair, Oscar Aguilar, Lewis Lanier, Jim Wells, Lawrence Fong, Robert Blelloch. PVRL2 suppresses antitumor immune responses through PVRIG- and TIGIT-independent pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB237.

Targeting osteosarcoma with canine B7-H3 CAR T cells and impact of CXCR2 Co-expression on functional activity

The use of large animal spontaneous models of solid cancers, such as dogs with osteosarcoma (OS), can help develop new cancer immunotherapy approaches, including chimeric antigen receptor (CAR) T cells. The goal of the present study was to generate canine CAR T cells targeting the B7-H3 (CD276) co-stimulatory molecule overexpressed by several solid cancers, including OS in both humans and dogs, and to assess their ability to recognize B7-H3 expressed by canine OS cell lines or by canine tumors in xenograft models. A second objective was to determine whether a novel dual CAR that expressed a chemokine receptor together with the B7-H3 CAR improved the activity of the canine CAR T cells. Therefore, in the studies reported here we examined B7-H3 expression by canine OS tumors, evaluated target engagement by canine B7-H3 CAR T cells in vitro, and compared the relative effectiveness of B7-H3 CAR T cells versus B7-H3-CXCR2 dual CAR T cells in canine xenograft models. We found that most canine OS tumors expressed B7-H3; whereas, levels were undetectable on normal dog tissues. Both B7-H3 CAR T cells demonstrated activation and OS-specific target killing in vitro, but there was significantly greater cytokine production by B7-H3-CXCR2 CAR T cells. In canine OS xenograft models, little anti-tumor activity was generated by B7-H3 CAR T cells; whereas, B7-H3-CXCR2 CAR T cells significantly inhibited tumor growth, inducing complete tumor elimination in most treated mice. These findings indicated therefore that addition of a chemokine receptor could significantly improve the anti-tumor activity of canine B7-H3 CAR T cells, and that evaluation of this new dual CAR construct in dogs with primary or metastatic OS is warranted since such studies could provide a critical and realistic validation of the chemokine receptor concept.

Plasmid DNA ionisable lipid nanoparticles as non-inert carriers and potent immune activators for cancer immunotherapy

Immunotherapy is currently a standard of care in the treatment of many malignancies. However, predictable side effects caused by systemic administration of highly immunostimulatory molecules have been a serious concern within this field. Intratumoural expression or silencing of immunogenic and immunoinhibitory molecules using nucleic acid-based approaches such as plasmid DNA (pDNA) and small interfering RNA (siRNA), respectively, could represent a next generation of cancer immunotherapy. Here, we employed lipid nanoparticles (LNPs) to deliver either non-specific pDNA and siRNA, or constructs targeting two prominent immunotherapeutic targets OX40L and indoleamine 2,3-dioxygenase-1 (IDO), to tumours in vivo.In the B16F10 mouse model, intratumoural delivery of LNP-formulated non-specific pDNA and siRNA led to strong local immune activation and tumour growth inhibition even at low doses due to the pDNA immunogenic nature. Replacement of these non-specific constructs by pOX40L and siIDO resulted in more prominent immune activation as evidenced by increased immune cell infiltration in tumours and tumour-draining lymph nodes. Consistently, pOX40L alone or in combination with siIDO could prolong overall survival, resulting in complete tumour regression and the formation of immunological memory in tumour rechallenge models. Our results suggest that intratumoural administration of LNP-formulated pDNA and siRNA offers a promising approach for cancer immunotherapy.

Abstract 3525: Towards the efficient design of shared neoantigen peptide cancer vaccines using artificial intelligence

Abstract Background: The advent of immune checkpoint inhibitors has improved morbidity and mortality for some cancers, and recent breakthroughs in gene & cell therapy have shed light on curing some types of blood cancers. However, many cancers remain intractable and the development of novel, effective and safe therapies continue to be a priority. Cancer vaccines as a cancer immunotherapy approach has seen a resurgence in recent years, due to the success of mRNA vaccines for the COVID-19. However, the accurate prediction of immunogenicity of cancer vaccines remains elusive. Methods: Our models predict the probability of a given peptide derived from the protein of interest to be presented by MHC-I or MHC-II. For MHC-I antigen presentation model development, over 17 million entries in the dataset were collected from published literature and available databases, e.g., IEDB, with peptide lengths ranging from 8 to 11. The peptides were restricted to 150 unique MHC-I alleles. Similarly, ~4 million entries with peptide lengths ranging from 13 to 21 were collected for MHC-II antigen presentation model development, and the peptides were restricted to 19 unique MHC-II alleles. To develop advanced antigen presentation models, a language model was chosen as the backbone network and contrast learning was used to better discriminate the peptide-MHC match versus mismatch. Overall, both MHC-I and MHC-II presentation models were constructed with about 30 million parameters. To validate the model prediction accuracy, automated peptide synthesis and surface plasmon resonance (SPR) technologies were applied. Results: Using open-sourced data, our developed AI models surpassed the performance of state-of-the-art prediction algorithms, the latest versions of NetMHCpan and MixMHCpred, for both MHC-I and MHC-II antigen presentation. Furthermore, to validate the algorithm accuracy and the peptide immunogenicity, 28 predicted patentable peptides derived from mutated TP53 protein were synthesized and their binding to respective common HLA alleles were validated using SPR. We found that greater than 80% of the peptides display binding affinities that are stronger than the positive control, suggesting that AI significantly improves neoantigen peptide vaccine design. Conclusions: We developed advanced AI algorithms to rapidly design shared neoantigen T cell epitopes with predicted strong binding affinity to MHC-I and MHC-II. We envision that the epitopes predicted and designed by our AI algorithms possess great potential in advancing the field of off-the-shelf cancer vaccine development and hold the promise of significantly benefiting patients, once translated into the clinic. Citation Format: Genwei Zhang, Jiewen Du, Xiangrui Gao, Tianyuan Wang, Zhenghui Wang, Qingxia Zhang, Tongren Liu, Dong Chen, Ruohan Zhu, Yalong Zhao, Chi Han Samson Li, Melvin Toh, Lipeng Lai. Towards the efficient design of shared neoantigen peptide cancer vaccines using artificial intelligence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3525.

Abstract 6737: Pharmacologic modulation of nonsense-mediated decay induces anti-tumor immunogenicity in ex vivo patient tumors

Abstract Introduction: Immunogenic neoantigens derived from somatic tumor mutations are essential to initiate and sustain robust anti-tumor immune responses. Frameshift insertion/deletions (fs-indels) are a key source of immunogenic neoantigens. However, fs-indels often result in the introduction of premature termination codons (PTCs), leading to mRNA degradation by the nonsense-mediated mRNA decay (NMD) pathway. In human malignancies, NMD activity is increased in response to the heightened burden of somatic fs-indel mutations and effectively prevents the generation of highly immunogenic tumor-specific neoantigens, thereby promoting immune evasion. Approach: Here, we pharmacologically targeted SMG1, a core component of the NMD pathway, for the first time in patient tumor and normal samples as well as in a panel of human cancer cell lines and patient-derived organoids, to prevent the degradation of highly immunogenic frame-shifted transcripts. We analyzed the changes in transcriptome, proteome and immunopeptidome following SMG1 inhibition (SMG1i). We then made use of tumor-T cell co-cultures and Patient-Derived Tumor Fragments (PDTFs) to assess the effects of SMG1i on anti-tumor immunogenicity. Ex vivo immunological responses were measured by high-dimensional flow cytometry, cytometric bead array and single cell RNA and TCR sequencing. Results: Our data demonstrates a significant increase in T cell activation, expansion of tumor-reactive intratumoural CD8+ lymphocytes and cytokine secretion following SMG1 inhibition in ex vivo PTDFs (n=15) but not in matched normal-adjacent tissue (n=10). Mechanistically, SMG1 inhibition increased the abundance of frame-shifted mRNA transcripts, and aberrant HLA-presented peptides. Co-culture of tumor cells and patient-derived organoids with CD8+ T cells upon SMG1 inhibition induced potent MHC class I antigen-dependent T cell activation and tumor cell killing. Conclusion: Our findings, in a clinically relevant platform, highlight SMG1 inhibition as a novel cancer immunotherapy approach to promote neoantigen production and to induce anti-tumor immunogenicity irrespective of the tumor type or TMB status. Citation Format: Roberto Vendramin, Hongchang Fu, Yue Zhao, Shanila Fernandez-Patel, Danwen Qian, Lorena Ligammari, Gordon Beattie, Ronen Levy, Polina Greenberg, Osnat Bartok, Krupa Thakkar, Jun Murai, Despoina Karagianni, Chris Sng, Mansi Shah, Felipe Galvez-Cancino, Krijn Djikstra, Sergio Quezada, Yardena Samuels, TRACERx consortium, James Reading, Charles Swanton, Kevin Litchfield. Pharmacologic modulation of nonsense-mediated decay induces anti-tumor immunogenicity in ex vivo patient tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6737.