Strong Antitumor Immune Response Research Articles

Protein expression of the amino acid transporter SLC7A5 in tumor tissue is prognostic in early-stage colorectal cancer

Proteins overexpressed in early-stage cancers may serve as early diagnosis and prognosis markers as well as targets for cancer therapies. In this study, we examined the expression of an essential amino acid carrier SLC7A5 (LAT1, CD98, or 4F2 light chain) in cancer tissue from two well-annotated cohorts of 575 cases of early-stage and 106 cases of late-stage colorectal cancer patients. Immunohistochemistry showed SLC7A5 overexpression in 72.0% of early-stage and 56.6% of late-stage cases. SLC7A5 expression was not influenced by patient gender, age, location, or mismatch repair status, although it appeared to be slightly less prevalent in tumors of mucinous differentiation or with lymphovascular invasion. Statistical analyses revealed a positive correlation between SLC7A5 overexpression and both overall survival and disease-free survival in early-stage but not late-stage cancers. Co-expression analyses of the TCGA and CPTAC colorectal cancer cohorts identified a network of gene transcripts positively related to SLC7A5, with its heterodimer partner SLC3A2 having the highest co-expression score. Network analysis uncovered the SLC7A network to be significantly associated with ncRNA such as tRNA processing and the mitotic cell cycle. Since SLC7A5 is also a marker of activated lymphocytes such as NK, T, and B lymphocytes, SLC7A5 overexpression in early colorectal cancers might trigger a strong anti-tumor immune response which could results in better clinical outcome. Overall, our study provides clear evidence of differential SLC7A5 expression and its prognostic value for early-stage colorectal cancer, although the understanding of its functions in colorectal tumorigenesis and cancer immunity is currently rather limited and awaits further characterization.

Abstract PO5-16-02: Investigating survivin as a novel target for immunotherapy in diverse breast cancer patients

Abstract Background: The BIRC5 gene encodes survivin, a tumor-specific antigen associated with aggressive tumor features, Black race and poor prognosis in breast cancer (BC). Recent studies have shown that anti-survivin vaccines stimulate a strong anti-tumor immune response in multiple tumor types. However, the relationship between BIRC5/survivin and immune response in BC is poorly understood, particularly among diverse patients. In this analysis, we sought to investigate the relationship between BIRC5/survivin and the BC immune microenvironment across clinical tumor features and RNA-based risk scores for genomic instability. Methods: We leveraged the Carolina Breast Cancer Study (CBCS), a large population-based study that oversampled young (≤50 years) and Black women with invasive BC. NanoString mRNA expression profiling was used to evaluate breast tumor expression for 10 major immune cell types, adaptive and innate immune response, TP53 and homologous recombination deficiency (HRD) pathways, and BIRC5/survivin from 1952 BC patients, including 1,030 (53%) Black and 922 (47%) non-Black women from the CBCS, with additional comparison in The Cancer genome Atlas (TCGA) (n=1,095 breast tumors). BIRC5 was evaluated both as a continuous and categorical variable, using the third expression quartile as a cut point for BIRC5-high, with the lower three quartiles categorized as BIRC5-low. We used generalized linear models to estimate beta values and adjusted p-values as the measure of association between BIRC5 status and immune-related expression in strata defined by estrogen receptor (ER) status, tumor stage, TP53 and HRD status. All analyses were adjusted for multiple comparisons with the Benjamini-Hochberg procedure. Results: In an analysis of continuous BIRC5 expression and global classes of immune response, BIRC5 mRNA expression was highest among tumors with an adaptive-enriched immune class (p< 0.001) in both CBCS and TCGA. However, when investigating immune gene expression according to BIRC5 status (i.e., BIRC5-high relative to BIRC5-low), multivariate differential expression analysis revealed significantly decreased immune cell-related expression scores among BIRC5-high tumors relative to BIRC5-low, and this relationship persisted in analysis stratified on stage (I/II vs III/IV), ER status, TP53 and HRD status. Across all strata, the strongest relationship between BIRC5-high and the immune microenvironment was observed for adaptive immune response (Beta: -0.14; p=0.005), with decreased immune gene expression related to B cells (Beta: -0.16; p=0.01), T cells (Beta: -0.14; p=0.007), Cytotoxic cells (Beta: -0.14; p=0.005), and PD-L1 (Beta: -0.15; p=0.005), relative to BIRC5-low. Conclusion: High BIRC5/survivin expression is associated with decreased immune-related gene expression in both ER-positive and ER-negative disease, and across all tumor stages. Anti-survivin therapies may be beneficial for boosting immune response in breast tumors with low immunogenicity, offering promise for BC subtypes previously ineligible for immunotherapy. Citation Format: Alina Hamilton, Qichen Wang, Sarah Soppe, Melissa Troester, Yara Abdou. Investigating survivin as a novel target for immunotherapy in diverse breast cancer patients [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-16-02.

Sulfonium-Stapled Peptides-Based Neoantigen Delivery System for Personalized Tumor Immunotherapy and Prevention.

Neoantigen peptides hold great potential as vaccine candidates for tumor immunotherapy. However, due to the limitation of antigen cellular uptake and cross-presentation, the progress with neoantigen peptide-based vaccines has obviously lagged in clinical trials. Here, a stapling peptide-based nano-vaccine is developed, comprising a self-assembly nanoparticle driven by the nucleic acid adjuvant-antigen conjugate. This nano-vaccine stimulates a strong tumor-specific T cell response by activating antigen presentation and toll-like receptor signaling pathways. By markedly improving the efficiency of antigen/adjuvant co-delivery to the draining lymph nodes, the nano-vaccine leads to 100% tumor prevention for up to 11 months and without tumor recurrence, heralding the generation of long-term anti-tumor memory. Moreover, the injection of nano-vaccine with signal neoantigen eliminates the established MC-38 tumor (a cell line of murine carcinoma of the colon without exogenous OVA protein expression) in 40% of the mice by inducing potent cytotoxic T lymphocyte infiltration in the tumor microenvironment without substantial systemic toxicity. These findings represent that stapling peptide-based nano-vaccine may serve as a facile, general, and safe strategy to stimulate a strong anti-tumor immune response for the neoantigen peptide-based personalized tumor immunotherapy.

Abstract NG04: Targeting DHX9 to trigger viral mimicry and immunotherapy responsiveness in small cell lung cancer

Abstract NG04: Targeting DHX9 to trigger viral mimicry and immunotherapy responsiveness in small cell lung cancer

Abstract LB275: Reactivation of mitotic arrest upon targeting TACC3 restores immunogenic cell death and T-DM1 response in HER2-positive breast cancer

Abstract Immunogenic cell death (ICD) is a specific form of cell death that is characterized by the release of danger-associated molecular patterns (DAMPs), such as cell surface exposure of calreticulin, ATP and HMGB1 release, and can be induced by several different anti-cancer therapies. This, in turn, evokes a strong anti-tumor immune response, leading to reduced tumor growth. Despite being the first and one of the most successful antibody-drug conjugates (ADCs) approved for refractory HER2-positive breast cancer, little is known if response and resistance to trastuzumab emtansine (T-DM1) involves ICD modulation that can be leveraged to enhance T-DM1 response. Here we report that T-DM1 induces spindle assembly checkpoint (SAC)-dependent ICD in sensitive cells, mediated by its payload by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which are lost in resistance. Accordingly, ICD-related gene signatures correlate with clinical response to T-DM1-containing therapy in pre-treatment samples, and increased infiltration of anti-tumor CD8+ T cells is correlated with better T-DM1 response in post-treatment samples. We found that transforming acidic coiled-coil containing 3 (TACC3) is overexpressed in T-DM1 resistant cells, and that T-DM1 responsive patients have reduced TACC3 protein while the non-responders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacological inhibition of TACC3 revives T-DM1-induced SAC activation and induction of ICD markers in vitro. TACC3 inhibition elicits ICD in vivo as shown by vaccination assay. It also potentiates T-DM1 in the human HER2-overexpressing MMTV-huHER2#5 (Fo5) transgenic model by activating ICD markers, release of cytokines and inducing dendritic cell (DC) maturation and enhancing infiltration of cytotoxic T cells. Together, our results show that ICD is a key mechanism of action of T-DM1 which is lost in resistance, and that targeting TACC3 restores T-DM1-mediated ICD and overcomes resistance. Citation Format: Ozge Saatci, Mustafa Emre Gedik, Nathaniel Oberholtzer, Meral Uner, Ozge Akbulut, Metin Cetin, Mertkaya Aras, Kubra Ibis, Burcu Caliskan, Erden Banoglu, Stefan Wiemann, Aysegul Uner, Sercan Aksoy, Shikhar Mehrotra, Ozgur Sahin. Reactivation of mitotic arrest upon targeting TACC3 restores immunogenic cell death and T-DM1 response in HER2-positive breast cancer [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 LB275.

Abstract 5135: Tertiary lymphoid structures and T-cell aggregates signal a robust anti-tumor immune response in a subset of leiomyosarcoma patients

Abstract Cancer immunotherapy has ushered in a new era for treatment of many difficult to treat cancers such as Leiomyosarcoma (LMS), one of the most common subtypes of sarcomas. There are few biomarkers which can be used to identify patients who might benefit from immunotherapy. There is an urgent need to discover novel biomarkers which might be prognostic of a strong anti-tumor response. We thus sought to comprehensively profile the microenvironment of LMS tumors to identify features which might be suggestive of an active immune response and molecular features prognostic of response to immunotherapy. We began our analysis by classifying the LMS tumors from The Cancer Genome Atlas (TCGA) into 4 subtypes based on previously identified molecular features and comparing the enrichment of various immune gene signatures. Two of the subtypes had a high expression of various immune gene signatures including B Cells, M2 macrophages and Cytotoxic T cells. Visual inspection of the Hematoxylin and Eosin-stained tissue slides available with TCGA pointed to a presence of lymphoid aggregates or Tertiary lymphoid structures (TLS) in 10-15% of the tumors - predominantly belonging to one of the two subtypes. This subtype displayed features of smooth muscle differentiation and was also associated with improved survival. To validate our findings, we performed immunohistochemistry (IHC) and bulk RNA sequencing of LMS specimens (n=66) obtained from surgical resections from the Johns Hopkins Hospital. We identified mature CD21+ TLS in 15% of these cases and non-germinal center T cell aggregates present in more than 30% of the cases and these features were associated with improved survival. We digitally merged the different IHC sections to study if the markers were spatially correlated. Interestingly, spatial analysis showed that these CD8 T cells aggregates co-localized with neighborhoods of high density of PD-L1+ cells, hinting at the possibility of immune mediated upregulation of PD-L1 as means of immune suppression. The deconvolution of the transcriptome of these samples showed a marked presence of cytotoxic CD8 T cells and plasma B cells in this subset of patients, an enrichment of pathways related to T cell trafficking, activation and proliferation. Single cell RNA sequencing of tumor infiltrating immune cells showed an oligoclonal expansion of B and T cells. Taken together, this study shows that a subset of LMS patients have a strong anti-tumor immune response which is characterized by the presence of Tertiary Lymphoid Structures and patches of high density of PD-L1 expressing cells. These features might serve as biomarkers in screening LMS patients which might benefit from immunotherapy. Citation Format: Aditya Suru, Alexandre Maalouf, Lingling Chen, Ada Tam, William Villasi, Kaushal Sharma, Lindy Zhang, Christian Meyer, Jonathan Greer, Fabian Johnston, Carol Morris, Sophia Strike, Adam Levin, Daniel Rhee, Brian Ladle, Kornel Schuebel, Yan Zhang, Rulin Wang, Srinivasan Yegnasubramanian, John Gross, Robert Anders, Andrew Pardoll, Nicolas Llosa. Tertiary lymphoid structures and T-cell aggregates signal a robust anti-tumor immune response in a subset of leiomyosarcoma patients [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 5135.

Abstract 5740: Peptide-functionalized dendrimers for enhanced binding to immune checkpoint proteins

Abstract The human immune system has complex and dynamic mechanisms to distinguish and eliminate malignant cells and defend the body against cancer. Various therapeutic approaches to stimulate the immune system have thus been investigated, demonstrating strong anti-tumor immune responses capable of controlling metastasis and preventing recurrence. Nevertheless, existing cancer immunotherapies suffer from several limitations, including inconsistent benefits across cancer types and patients. In recent years, the utilization of peptides for immunotherapy has attracted a great deal of interest due to their ability to mimic protein functionalities while maintaining a high degree of modularity and synthetic reproducibility in their molecular design. However, the clinical translation of otherwise promising peptide-based immunotherapeutics has been hindered due to their significantly weaker binding to target proteins and short half-life in plasma circulation in comparison to their monoclonal antibody counterparts. Nevertheless, these issues can potentially be addressed by conjugation to nanoparticles, which enhances cell binding/uptake and prolongs circulation. To this end, our group has extensively investigated the use of poly(amidoamine) (PAMAM) dendrimers to improve the therapeutic utility of peptides. These dendrimers can facilitate the simultaneous binding of conjugated peptides to multiple cell receptors, resulting in a significantly enhanced binding interaction through the multivalent binding effect. Here, we report an efficient de novo nanoparticle design strategy that combines organic synthesis, phage display, and molecular dynamics to identify a novel immuno-oncology therapeutic modality. We first employed phage display to identify several highly selective sequences that bind to the mouse ortholog of TIGIT—an inhibitory receptor expressed on lymphocytes that has been identified as a potential therapeutic target to enhance anti-tumor immune responses. Subsequent computational modeling (NAMD with CHARMM force field) revealed several conserved regions of interaction that we hypothesize drive favorable binding interactions and enhance the binding affinity of the peptide inhibitors. We next incorporated experimental kinetic measurements of the identified sequences with adaptive evolution computational modeling to identify optimized mutant analogs for dendrimer conjugation. It was found that the TIGIT targeting DPCs (dendrimer-peptide conjugates) demonstrated increased binding avidity in vitro and anti-tumor efficacy in vivo, most notably when administered in combination with PD-L1 targeting DPCs to a syngeneic mouse model bearing mouse oral carcinoma (MOC1) tumors. Overall, this work demonstrates the potential of rational peptide design and our multi-functional DPC platform for the development of both effective and novel immuno-oncology therapeutics. Citation Format: Piper Anne Rawding, Francesco Coppola, DaWon Kim, Michael Poellmann, Deric Wheeler, Petr Král, Seungpyo Hong. Peptide-functionalized dendrimers for enhanced binding to immune checkpoint proteins [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 5740.

Abstract 6755: NKT activation enhanced the therapeutic efficacy of neoantigen vaccine in hepatocellular carcinoma

Abstract One sentence introduction: This study indicated the potential of combinational therapy of neoantigen vaccine and iNKT activator α-GalCer in Hepatocellular carcinoma. Hepatocellular carcinoma (HCC) is a leading cause of death around the world. Current immune checkpoint blockade therapies only show effectiveness in some cancer patients, so there is an urgent need for more effective immunotherapy strategies. One alternative is the use of neoantigen-based cancer vaccines, which target tumor-specific antigens (neoantigens) on cancer cells and induce strong T-cell responses. Advances in technology now allow for precise identification of tumor neoantigens using bioinformatic analysis or mass spectrometry. While cancer vaccines have demonstrated strong anti-tumor immune responses and therapeutic effectiveness in some cancer types, their success in HCC remains limited. A contributing factor is the suppressive tumor microenvironment (TME) found in advanced HCC. Some studies suggest that combining neoantigen vaccines with anti-PD1/PD-L1 therapies can significantly enhance HCC treatment outcomes. Overcoming the suppressive immune microenvironment is crucial in cancer treatment, and reactivating intratumoral immunity is essential. In our study, we developed an HCC cancer vaccine using transcriptome sequencing and bioinformatics analysis. Our ELISpot assay results showed that this vaccine induced strong tumor-specific immune responses and significantly inhibited tumor growth in early-stage orthotopic HCC mouse models when administered five days after tumor inoculation. However, the effectiveness decreased in advanced tumors when administered ten days after tumor inoculation. We also discovered a significant relationship between the therapeutic effectiveness of the neoantigen vaccine and the activation of intratumoral NKT cells in HCC. Our study suggested that the type-I NKT cell activator, α-Galactosylceramide (α-GalCer), significantly improved the therapeutic outcomes of the cancer neoantigen vaccine in advanced orthotopic HCC mouse models. In some cases, tumors were almost completely eliminated. This indicates the potential of combining iNKT activators with neoantigen vaccines for HCC treatment. To further understand the role of NKT cells in HCC's TME, we plan to investigate intratumoral NKT cell subtypes following neoantigen vaccine therapy. Additionally, we will develop a new delivery system to deliver type I NKT cell activators and type II NKT inhibitors to tumor sites, aiming to reactivate the suppressive TME in HCC after neoantigen vaccine therapy. Citation Format: Renhao Li, Jing-Chu Hu, Li Rong, Yangfan Wu, Yige He, Jiandong Huang. NKT activation enhanced the therapeutic efficacy of neoantigen vaccine in hepatocellular carcinoma [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 6755.

Abstract 1358: Elucidating the contribution of T cell-intrinsic VISTA to the suppression of antitumor T cell immunity

Abstract Immune checkpoint receptors (ICRs) negatively regulate antitumor immune responses. While significant advances have been made in understanding the mechanisms of well-established ICRs such as PD-1 and CTLA-4, other checkpoint proteins remain incompletely characterized and may be targeted to synergistically boost antitumor immunity. One such protein is V-domain immunoglobulin suppressor of T-cell activation (VISTA), an ICR whose expression curtails the function of several lymphoid and myeloid lineages, including tumor-reactive cytotoxic T cells. Globally blocking VISTA elicits potent T cell-mediated antitumor immunity and systemic myeloid cell-mediated inflammatory responses. Mechanistically, VISTA has been shown to inhibit T cell activation by acting as an inhibitory ligand on antigen-presenting cells. However, the impact of T cell-intrinsic VISTA on modulating tumor-reactive T cell responses has not been thoroughly investigated, and it remains unclear whether blocking T cell-specific VISTA is adequate for revitalizing T cell-mediated tumor control. In this study, we utilized VISTA conditional knockout mice models to examine the relative contribution of T cell-intrinsic VISTA versus myeloid-derived VISTA in the regulation of antitumor immunity. We present evidence that blocking VISTA on T cells alone is insufficient to induce strong antitumor immune responses, whereas blocking VISTA on myeloid cells counteracts its dominant role in orchestrating T cell suppression. Citation Format: Sachin Patnaik, Elizabeth Delaney, Cassandra Gilmour, Keman Zhang, Amin Zakeri, Hieu M. Ta, Prerana B. Parthasarathy, Tyler Alban, Timothy Chan, Li Lily Wang. Elucidating the contribution of T cell-intrinsic VISTA to the suppression of antitumor T cell immunity [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 1358.

Influence of intestinal microbial metabolites on the abscopal effect after radiation therapy combined with immune checkpoint inhibitors

BackgroundMost clinical studies failed to elicit a strong antitumor immune response and subsequent systemic tumor regression after radiation therapy (RT), even in combination with the immune checkpoint inhibitors (ICI) anti-CTLA4 or anti-PD1. Mechanistically, type I interferon (IFN-I) activation is essential for the development of such abscopal effects (AE); however, mechanisms driving or limiting IFN–I activation are ill defined. Groundbreaking discoveries have shown that antibiotics (ABx) can affect oncological outcomes and that microbiota-derived metabolites can modulate systemic antitumor immunity. Recent studies have demonstrated that the bacterial metabolites desaminotyrosine (DAT) and indole-3-carboxaldehyde (ICA) can enhance IFN-I activation in models of inflammatory diseases. Materials and MethodsThe subcutaneous bilateral MC38 tumor model is a widely used experimental tool to study the AE in mice. We applied it to explore the influence of broad-spectrum ABx, DAT and ICA on the AE after radioimmunotherapy (RIT). We performed 1x8 Gy of the primary tumor ± anti-CTLA4 or anti-PD1, and ± daily oral application of ABx or metabolites. ResultCombinatory ABx had neither a significant effect on tumor growth of the irradiated tumor nor on tumor progression of the abscopal tumor after RIT with anti-CTLA4. Furthermore, DAT and ICA did not significantly impact on the AE after RIT with anti-CTLA4 or anti-PD1. Surprisingly, ICA even appears to reduce outcomes after RIT with anti-CTLA4. ConclusionWe did not find a significant impact of combinatory ABx on the AE. Experimental application of the IFN-I-inducing metabolites DAT or ICA did not boost the AE after combined RIT. Additional studies are important to further investigate whether the intestinal microbiota or specific microbiota-derived metabolites modulate the AE.

Personalized neoantigen vaccine enhances the therapeutic efficacy of bevacizumab and anti-PD-1 antibody in advanced non-small cell lung cancer

Clinically, a considerable number of non-small cell lung cancer (NSCLC) patients are unable to receive or resist chemotherapy, and the efficacy of non-chemotherapy treatment strategies based on anti-angiogenic agents combined with immune checkpoint blockade is still unsatisfactory. Neoantigen vaccine, based on personalized tumor DNA mutations, could elicit tumor specific T cell infiltration into the tumor site, exerting potent anti-tumor efficacy. Here, we evaluated the feasibility and safety of a new antitumor strategy by adding neoantigen vaccine to the regimen of bevacizumab and anti-PD-1 antibody. Firstly, 7 novel immunogenic neoantigen peptides were identified and developed for neoantigen vaccine (LLCvac), which can elicit strong antitumor immune response in vivo. Then, in orthotopic lung cancer model, LLCvac further combining with bevacizumab and anti-PD-1 antibody exerted a stronger antitumor effect, exhibiting significant decrease of tumor volume without obvious toxicity. Furthermore, tumor immune microenvironment assessment also showed that the proportion of neoantigen-specific T cells in blood could be induced dramatically by the combined therapy. And a large amount of neoantigen-specific Ki67-positive CD8+ T cells were found in tumor tissues, which infiltrated tumor tissues effectively to kill tumor cells expressing identified neoantigens. Overall, these results suggested that this combined therapy could safely induce robust antitumor efficacy, serving as an effective chemotherapy-free strategy for NSCLC treatment.

Hypoxia-activated cascade nanovaccine for synergistic chemoembolization-immune therapy of hepatocellular carcinoma

In this work, a promising treatment strategy for triggering robust antitumor immune responses in transarterial chemoembolization of hepatocellular carcinoma (HCC) is presented. The zeolitic imidazolate framework nanoparticles loaded with hypoxia-activated prodrug tirapazamine and immune adjuvant resiquimod facilitated in situ generation of nanovaccine via a facile approach. The nanovaccine can strengthen the ability of killing the liver cancer cells under hypoxic environment, while was capable of improving immunogenic tumor microenvironment and triggering strong antitumor immune responses by increasing the primary and distant intratumoral infiltration of immune cells such as cytotoxic T cells. Moreover, a porous microcarrier, approved by FDA as pharmaceutical excipient, was designed to achieve safe and effective delivery of the nanovaccine via transarterial therapy in rabbit orthotopic VX2 liver cancer model. The microcarrier exhibited the characteristics of excellent drug loading and occlusion of peripheral artery. The collaborative delivery of the microcarrier and nanovaccine demonstrated an exciting inhibitory effect on solid tumors and tumor metastases, which provided a great potential as novel combination therapy for HCC interventional therapy.

Assembling Au8 clusters on surfaces of bifunctional nanoimmunomodulators for synergistically enhanced low dose radiotherapy of metastatic tumor

BackgroundRadiotherapy is one of the mainstays of cancer therapy and has been used for treating 65–75% of patients with solid tumors. However, radiotherapy of tumors has two limitations: high-dose X-rays damage adjacent normal tissue and tumor metastases cannot be prevented.ResultsTherefore, to overcome the two limitations of radiotherapy, a multifunctional core–shell R837/BMS@Au8 nanoparticles as a novel radiosensitizer were fabricated by assembling Au8NCs on the surface of a bifunctional nanoimmunomodulator R837/BMS nanocore using nanoprecipitation followed by electrostatic assembly. Formed R837/BMS@Au8 NP composed of R837, BMS-1, and Au8 clusters. Au8NC can enhance X-ray absorption at the tumor site to reduce X-ray dose and releases a large number of tumor-associated antigens under X-ray irradiation. With the help of immune adjuvant R837, dendritic cells can effectively process and present tumor-associated antigens to activate effector T cells, meanwhile, a small-molecule PD-L1 inhibitor BMS-1 can block PD-1/PD-L1 pathway to reactivate cytotoxic T lymphocyte, resulting in a strong systemic antitumor immune response that is beneficial for limiting tumor metastasis. According to in vivo and in vitro experiments, radioimmunotherapy based on R837/BMS@Au8 nanoparticles can increase calreticulin expression on of cancer cells, reactive oxygen species generation, and DNA breakage and decrease colony formation. The results revealed that distant tumors were 78.2% inhibited depending on radioimmunotherapy of primary tumors. Therefore, the use of a novel radiosensitizer R837/BMS@Au8 NPs realizes low-dose radiotherapy combined with immunotherapy against advanced cancer.ConclusionIn conclusion, the multifunctional core–shell R837/BMS@Au8 nanoparticles as a novel radiosensitizer effectively limiting tumor metastasis and decrease X-ray dose to 1 Gy, providing an efective strategy for the construction of nanosystems with radiosensitizing function.

Smart Tumor Cell-Derived DNA Nano-Tree Assembly for On-Demand Macrophages Reprogramming.

Without coordinated strategies to balance the population and activity of tumor cells and polarized macrophages, antitumor immunotherapy generally offers limited clinical benefits. Inspired by the "eat me" signal, a smart tumor cell-derived proximity anchored non-linear hybridization chain reaction (Panel-HCR) strategy is established for on-demand regulation of tumor-associated macrophages (TAMs). The Panel-HCR is composed of a recognition-then-assembly module and a release-then-regulation module. Upon recognizing tumor cells, a DNA nano-tree is assembled on the tumor cell surface and byproduct strands loaded with CpG oligodeoxynucleotides (CpG-ODNs) are released depending on the tumor cell concentration. The on-demand release of CpG-ODNs can achieve efficient regulation of M2 TAMs into the M1 phenotype. Throughout the recognition-then-assembly process, tumor cell-targeted bioimaging is implemented in single cells, fixed tissues, and living mice. Afterward, the on-demand release of CpG-ODNs regulate the transformation of M2 TAMs into the M1 phenotype by stimulating toll-like receptor 9 to activate the NF-κB pathway and increasing inflammatory cytokines. This release-then-regulation process is verified to induce strong antitumor immune responses both in vitro and in vivo. Altogether, this proposed strategy holds tremendous promise for on-demand antitumor immunotherapy.

Strengthening the Combinational Immunotherapy from Modulating the Tumor Inflammatory Environment via Hypoxia-Responsive Nanogels.

Despite the success of immuno-oncology in clinical settings, the therapeutic efficacy is lower than the expectation due to the immunosuppressive inflammatory tumor microenvironment (TME) and the lack of functional lymphocytes caused by exhaustion. To enhance the efficacy of immuno-oncotherapy, a synergistic strategy should be used that can effectively improve the inflammatory TME and increase the tumor infiltration of cytotoxic T lymphocytes (CTLs). Herein, a TME hypoxia-responsive nanogel (NG) is developed to enhance the delivery and penetration of diacerein and (-)-epigallocatechin gallate (EGCG) in tumors. After systemic administration, diacerein effectively improves the tumor immunosuppressive condition through a reduction of MDSCs and Tregs in TME, and induces tumor cell apoptosis via the inhibition of IL-6/STAT3 signal pathway, realizing a strong antitumor effect. Additionally, EGCG can effectively inhibit the expression of PD-L1, restoring the tumor-killing function of CTLs. The infiltration of CTLs increases at the tumor site with activation of systemic immunity after the combination of TIM3 blockade therapy, ultimately resulting in a strong antitumor immune response. This study provides valuable insights for future research on eliciting effective antitumor immunity by suppressing adverse tumor inflammation. The feasible strategy proposed in this work may solve the urgent clinical concerns of the dissatisfactory checkpoint-based immuno-oncotherapy.

Abstract A066: TUSC2 immunogene therapy enhances checkpoint blockade through increased cytotoxic immune activation in chemo-resistant small cell lung cancer (SCLC) in humanized mice

Abstract Immunotherapy has been effective but has had limited effect in clinical trials for SCLC. We identified TUSC2, a potent tumor suppressor gene, as a novel immunogene, which mediates both apoptosis and induces a strong antitumor immune response. TUSC2 expression is reduced in almost all SCLC tumors and absent in 41%. We investigated the antitumor immune response to TUSC2 gene therapy in combination with immune checkpoint blockade (ICB) against a chemo-resistant inflamed SCLC tumors in humanized mice. Colony formation was markedly reduced in platinum resistant inflamed H841 cells transfected with TUSC2. Humanized mice were generated by transplanting fresh human cord blood derived CD34 stem cells into sub-lethally irradiated NSG mice(hu-NSG). The level of engraftment of human CD45, CD3 T, CD19 B, NK cells was verified before tumor implantation at > 25%. Subcutaneous tumors were developed in hu-NSG mice and treated with intravenous injections of TUSC2 loaded cationic lipid nanoparticles (quaratusugene ozeplasmid abbreviated quar oze) with or without pembrolizumab (pembro; anti-PD1). A dramatic antitumor effect was mediated by quar oze, whereas pembro remained ineffective. A synergistic antitumor effect was found when quar oze was combined with pembro. The antitumor effect of the quar oze + pembro was associated with increased infiltration of human TILs, CD3 T, cytotoxic T, and NK cells, and a decreased number of human regulatory T (Treg) cells, and PD1 expressing exhausted CD8 T cells in the tumor microenvironment. Quar oze was also combined with atezolizumab (atezo; anti-PD-L1) and the antitumor effect on H841 lung metastases in hu-NSG mice was tested. Metastases were treated with quar oze and atezo alone or in combination. Although quar oze alone and atezo alone showed a strong antitumor effect in controlling metastases, a greater antitumor effect was found when quar oze was combined with atezo. Infiltration of human CD45, CD3 T, CD8 T and NK cells increased in the quar oze and quar oze +atezo treated groups compared with others. A significantly higher number of CD8 T effector memory and lower number of naïve T cells were found in the quar oze +atezo which were associated with increased activated CD8 T cells (CD69+, PD1+ CD8 T cells). HLA-DR+ dendritic cells were increased, whereas myeloid derived suppressor cells were strongly inhibited by the combination. Quar oze was also combined with carboplatin+atezo which showed enhanced antitumor efficacy compared with carbo+atezo or quar oze alone. When quar oze was combined with carboplatin, a greater effect was found in inhibiting H841 cell growth, colony formation, and induction of apoptosis. Quar oze was combined with NPRL2, another tumor suppressor gene, in H841 tumors in humanized mice. Synergistic antitumor efficacy of the dual gene therapy occurred with the quar oze +NPRL2 treatment. Taken together, these data suggest that TUSC2 gene therapy in combination with ICB induces strong antitumor activity on a chemo-resistant inflamed SCLC through cytotoxic CD8 T and NK cell activation. Citation Format: Ismail M Meraz, Mourad Majidi, Renduo Song, Feng Meng, Lihui Gao, Qi Wang, Jing Wang, Elizabeth Shpall, Mark Berger, Hemant Kumar, Jack A Roth. TUSC2 immunogene therapy enhances checkpoint blockade through increased cytotoxic immune activation in chemo-resistant small cell lung cancer (SCLC) in humanized mice [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A066.

Dual‐Functional Artificial Peroxidases with Ferriporphyrin Centers for Amplifying Tumor Immunotherapies via Immunogenic Cell Death

AbstractConstructing highly effective sonosensitizers that integrate tumor microenvironment (TME)‐adaptive and ultrasound (US)‐controllable production of reactive oxygen species (ROS) to amplify tumor immunotherapies is extremely desirable but remains challenging. Here, inspired by the coordination structure and biocatalytic effects of Fe‐based peroxidase, a dual‐functional artificial peroxidase is synthesized with ferriporphyrin networks (FePorNW‐DAP) to serve a TME‐adaptive and US‐controllable ROS‐generator for amplifying tumor immunotherapies in breast cancer via immunogenic cell death. Owing to the structural advantages of the ferriporphyrin‐based large d–π‐conjugated networks with the monatomic Fe─N4 coordination center, moderate interaction with H2O2, and decreased bandgap, the FePorNW‐DAP displays efficient dual‐functional ROS production capabilities to combat tumor cells and amplify the tumor immunotherapies, 1) utilize locally produced H2O2 in the TME to catalytically generate potent •OH and other ROS species; simultaneously, 2) external US irradiation can further boost the generation of •OH and 1O2. This work provides not only critical evidence that the proposed dual‐functional artificial peroxidases can induce a strong antitumor immune response and immune memory but also offers essential guidance for creating a high‐performance and biocompatible strategy to regulate the immunosuppression TME and enhance the antitumor immune responses of breast cancer.

Ferritin-Based Nanocomposite Hydrogel Promotes Tumor Penetration and Enhances Cancer Chemoimmunotherapy.

Hydrogels are prevailing drug delivery depots to improve antitumor efficacy and reduce systemic toxicity. However, the application of conventional free drug-loaded hydrogel is hindered by poor drug penetration in solid tumors. Here, an injectable ferritin-based nanocomposite hydrogel is constructed to facilitate tumor penetration and improve cancer chemoimmunotherapy. Specifically, doxorubicin-loaded human ferritin (Dox@HFn) and oxidized dextran (Dex-CHO) are used to construct the injectable hydrogel (Dox@HFn Gel) through the formation of pH-sensitive Schiff-base bonds. After peritumoral injection, the Dox@HFn Gel is retained locally for up to three weeks, and released intact Dox@HFn gradually, which can not only facilitate tumor penetration through active transcytosis but also induce immunogenic cell death (ICD) to tumor cells to generate an antitumor immune response. Combining with anti-programmed death-1 antibody (αPD-1), Dox@HFn Gel induces remarkable regression of orthotopic 4T1 breast tumors, further elicits a strong systemic anti-tumor immune response to effectively suppress tumor recurrence and lung metastasis of 4T1 tumors after surgical resection. Besides, the combination of Dox@HFn GelL with anti-CD47 antibody (αCD47) inhibits postsurgical tumor recurrence of aggressive orthotopic glioblastoma tumor model and significantly extends mice survival. This work sheds light on the construction of local hydrogels to potentiate antitumor immune response for improved cancer therapy.

MODL-34. A SERIES OF EGFR-MUTANT MODELS OF GLIOBLASTOMA THAT RECAPITULATES PATIENT TUMOR HETEROGENEITY AND RESPONSE TO TREATMENT

Abstract Glioblastoma (GBM) is the most common and aggressive brain cancer, with a treatment regimen that has remained disappointingly unaltered for the last few decades. Preclinical testing of immunotherapy has generated promising results, sometimes leading to elimination of the tumor over time in mouse models; however, when tested clinically, patients show limited responses with no impact on patient survival. Current mouse models (e.g., GL261) for preclinical testing involve orthotopic transplantation of a cell line with tumor mutations not commonly found in patient tumors. Most of these models elicit a strong anti-tumor immune response which is typically not found clinically. Single cell sequencing has revealed that different mutations in GBM are associated with differences in the aggressiveness and composition of the tumor immune microenvironment. We therefore developed an immunocompetent, autochthonous platform for generating mouse models of GBM using combinations of clinically-relevant mutations, including mutant EGFR driving tumor growth and various single guide RNAs with CRISPR-Cas9 to elicit loss of function of tumor suppressor genes. Histopathology from tumors in mice mirrors the typical features of GBM, while single-cell RNA sequencing identified expression patterns similar to patients with different driver combinations altering expression patterns in ways that mimic their human counterparts, including the heterogeneity that is the hallmark of GBM. The immune cell population of these tumors was composed of predominantly microglia, with a small population of peripherally derived immune cells. Finally, treatment studies of radiation and anti-PD-1 using this new mouse model do not result in long-term survival, similar to human trials of these agents, paving the way for more accurate preclinical testing. In conclusion, using this unique modeling system that more closely resembles human tumors genetically and immunologically, we can better explore the mechanisms of therapeutic resistance and identify more relevant targets to improve outcomes in this challenging disease.

Fabrication of An Immunostimulatory Supramolecular Nanomedicine for Potent Cancer Chemoimmunotherapy.

Chemoimmunotherapy can boost strong antitumor immune responses by triggering immunogenic cell death (ICD), which highlights a promising prospect in clinical applications. However, current chemoimmunotherapy shows limited efficacy due to the low delivery efficiency and insufficient immunogenicity of available chemotherapeutic drugs. A supramolecular polymeric nanomedicine (Pt-Tu@NP) is herein reported using cucurbit[7]uril-based host-guest recognition and noncovalent self-assembly. Pt-Tu@NPs have excellent biodistribution and strongly evoke the endoplasmic reticulum stress-mediated ICD of tumor cells, triggering potent antitumor immune responses by promoting dendritic cell (DC) maturation and cytotoxic T cell infiltration. The coordinated butyrate promotes a positive feedback regulation between DCs and CD8+ T cells. Pt-Tu@NPs stimulate immune cold tumors into hot ones, working in synergy with an immune checkpoint blockade to effectively suppress tumor growth and metastasis, which suggests a promising approach for cancer chemoimmunotherapy.