Effective Cancer Immunotherapy Research Articles

Effect of cancer immunotherapy with CD39/PD-L1 bispecific antibody OriA631-b.

e14508 Background: Despite significant advancements in cancer immunotherapy through the use of immune checkpoint inhibitors, there remains a need for more robust strategies to enhance anti-tumor immune responses. This study introduces and characterizes OriA631-B, an innovative CD39/PD-L1 bispecific antibody. By simultaneously targeting the metabolic checkpoint CD39 and the immune checkpoint PD-L1, this novel antibody has the potential to significantly augment anti-tumor efficacy, particularly in cold tumors characterized by a scarcity of infiltrating immune cells. The development of OriA631-B marks a breakthrough in concurrently addressing two crucial immunosuppressive pathways. Methods: The creation of OriA631-B involved cutting-edge antibody engineering methodologies to guarantee optimal binding affinity and specificity for its target antigens, CD39 and PD-L1. With meticulous design and refinement, OriA631-B was developed to exhibit robust binding capabilities to both CD39 and PD-L1, enabling simultaneous and precise recognition. Leveraging advanced antibody engineering techniques was instrumental in crafting OriA631-B as a potent tool with heightened binding properties, broadening its potential applications across diverse therapeutic contexts. Results: In vitro investigations revealed the efficacy of OriA631-B, derived from the foundation of a clinically validated in-house generated PD-L1 antibody (YN035). This innovative antibody effectively thwarted CD39-mediated adenosine production, resulting in heightened effector T cell function and proliferation. In vivo efficacy assessments conducted on syngeneic hot tumor models MC38 and Hepa1-6 underscored the remarkable effectiveness of OriA631, the CD39 monoclonal antibody (mAb), in controlling tumor growth. Notably, OriA631-B, the CD39/PD-L1 bispecific antibody, exhibited even more profound impacts, significantly restraining tumor growth beyond the effects observed with single-target treatments in the hot tumor model or combination therapies in both the hot tumor model MC38 and the cold tumor model CT26. These findings underscore the potent therapeutic potential of OriA631-B and its capacity to exert robust anti-tumor activity by concurrently targeting CD39 and PD-L1. Additionally, safety profiling revealed an acceptable toxicity profile for OriA631-B, with no significant adverse events observed during the study. Conclusions: In summary, OriA631-B demonstrates potential as an innovative immunotherapeutic strategy for cancer treatment by concurrently targeting CD39-mediated immune suppression and PD-L1-mediated T cell exhaustion. Further exploration, including clinical trials, is imperative to fully uncover the therapeutic capabilities of this groundbreaking bispecific antibody in cancer immunotherapy.

A bioactive nanocomposite integrated specific TAMs target and synergistic TAMs repolarization for effective cancer immunotherapy

Reactive oxygen species (ROS) generated from photosensitizers exhibit great potential for repolarizing immunosuppressive tumor-associated macrophages (TAMs) toward the anti-tumor M1 phenotype, representing a promising cancer immunotherapy strategy. Nevertheless, their effectiveness in eliminating solid tumors is generally limited by the instability and inadequate TAMs-specific targeting of photosensitizers. Here, a novel core-shell integrated nano platform is proposed to achieve a coordinated strategy of repolarizing TAMs for potentiating cancer immunotherapy. Colloidal mesoporous silica nanoparticles (CMSN) are fabricated to encapsulate photosensitizer-Indocyanine Green (ICG) to improve their stability. Then ginseng-derived exosome (GsE) was coated on the surface of ICG/CMSN for targeting TAMs, as well as repolarizing TAMs concurrently, named ICG/CMSN@GsE. As expected, with the synergism of ICG and GsE, ICG/CMSN@GsE exhibited better stability, mild generation of ROS, favorable specificity toward M2-like macrophages, enhancing drug retention in tumors and superior TAMs repolarization potency, then exerted a potent antitumor effect. In vivo, experiment results also confirm the synergistic suppression of tumor growth accompanied by the increased presence of anti-tumor M1-like macrophages and maximal tumor damage. Taken together, by integrating the superiorities of TAMs targeting specificity and synergistic TAMs repolarization effect into a single nanoplatform, ICG/CMSN@GsE can readily serve as a safe and high-performance nanoplatform for enhanced cancer immunotherapy.

PD-L1 targeted peptide demonstrates potent antitumor and immunomodulatory activity in cancer immunotherapy.

In recent years, immunotherapy has been emerging as a promising alternative therapeutic method for cancer patients, offering potential benefits. The expression of PD-L1 by tumors can inhibit the T-cell response to the tumor and allow the tumor to evade immune surveillance. To address this issue, cancer immunotherapy has shown promise in disrupting the interaction between PD-L1 and its ligand PD-1. We used mirror-image phage display technology in our experiment to screen and determine PD-L1 specific affinity peptides (PPL-C). Using CT26 cells, we established a transplanted mouse tumor model to evaluate the inhibitory effects of PPL-C on tumor growth in vivo. We also demonstrated that PPL-C inhibited the differentiation of T regulatory cells (Tregs) and regulated the production of cytokines. In vitro, PPL-C has a strong affinity for PD-L1, with a binding rate of 0.75 μM. An activation assay using T cells and mixed lymphocytes demonstrated that PPL-C inhibits the interaction between PD-1 and PD-L1. PPL-C or an anti-PD-L1 antibody significantly reduced the rate of tumor mass development in mice compared to those given a control peptide (78% versus 77%, respectively). The results of this study demonstrate that PPL-C prevents or retards tumor growth. Further, immunotherapy with PPL-C enhances lymphocyte cytotoxicity and promotes proliferation in CT26-bearing mice. PPL-C exhibited antitumor and immunoregulatory properties in the colon cancer. Therefore, PPL-C peptides of low molecular weight could serve as effective cancer immunotherapy.

Aldehyde Dehydrogenese-1 High Cancer Stem-like Cells/Cancer-initiating Cells Escape from Cytotoxic T Lymphocytes due to Lower Expression of Human Leukocyte Antigen Class 1.

Human gastric cancer stem-like cells (CSCs)/cancer-initiating cells can be identified as aldehyde dehydrogenase-high (ALDHhigh) cells. Cancer immunotherapy employing immune checkpoint blockade has been approved for advanced gastric cancer cases. However, the effectiveness of cancer immunotherapy against gastric CSCs/CICs remains unclear. This study aimed to investigate the susceptibility of gastric CSCs/CICs to immunotherapy. Gastric CSCs/CICs were isolated as ALDHhigh cells using the human gastric cancer cell line, MKN-45. ALDHhigh clone cells and ALDHlow clone cells were isolated using the ALDEFLUOR assay. ALDH1A1 expression was assessed via qRT-PCR. Sphere-forming ability was evaluated to confirm the presence of CSCs/CICs. A model neoantigen, AP2S1, was over-expressed in ALDHhigh clone cells and ALDHlow clone cells, and susceptibility to AP2S1-specific TCR-T cells was assessed using IFNγ ELISPOT assay. Three ALDHhigh clone cells were isolated from MKN-45 cells. ALDHhigh clone cells exhibited a stable phenotype in in vitro culture for more than 2 months. The High-36 clone cells demonstrated the highest sphere-forming ability, whereas the Low-8 cells showed the lowest sphere-forming ability. High-36 cells exhibited lower expression of HLA-A24 compared to Low-8 cells. TCR-T cells specific for AP2S1 showed lower reactivity to High-36 cells compared to Low-8 cells. High-36 cells and Low-8 cells represent novel gastric CSCs/CICs and non-CSCs/CICs, respectively. ALDHhigh CSCs/CICs evade T cells due to lower expression of HLA class 1.

The role of B-1 cells in cancer progression and anti-tumor immunity.

In recent years, in addition to the well-established role of T cells in controlling or promoting tumor growth, a new wave of research has demonstrated the active involvement of B cells in tumor immunity. B-cell subsets with distinct phenotypes and functions play various roles in tumor progression. Plasma cells and activated B cells have been linked to improved clinical outcomes in several types of cancer, whereas regulatory B cells have been associated with disease progression. However, we are only beginning to understand the role of a particular innate subset of B cells, referred to as B-1 cells, in cancer. Here, we summarize the characteristics of B-1 cells and review their ability to infiltrate tumors. We also describe the potential mechanisms through which B-1 cells suppress anti-tumor immune responses and promote tumor progression. Additionally, we highlight recent studies on the protective anti-tumor function of B-1 cells in both mouse models and humans. Understanding the functions of B-1 cells in tumor immunity could pave the way for designing more effective cancer immunotherapies.

CXCR4-Targeted Macrophage-Derived Biomimetic Hybrid Vesicle Nanoplatform for Enhanced Cancer Therapy through Codelivery of Manganese and Doxorubicin.

Immune-cell-derived membranes have garnered significant attention as innovative delivery modalities in cancer immunotherapy for their intrinsic immune-modulating functionalities and superior biocompatibilities. Integrating additional parental cell membranes or synthetic lipid vesicles into cellular vesicles can further potentiate their capacities to perform combinatorial pharmacological activities in activating antitumor immunity, thus providing insights into the potential of hybrid cellular vesicles as versatile delivery vehicles for cancer immunotherapy. Here, we have developed a macrophage-membrane-derived hybrid vesicle that has the dual functions of transporting immunotherapeutic drugs and shaping the polarization of tumor-associated macrophages for cancer immunotherapy. The platform combines M1 macrophage-membrane-derived vesicles with CXCR4-binding-peptide-conjugated liposomes loaded with manganese and doxorubicin. The hybrid nanovesicles exhibited remarkable macrophage-targeting capacity through the CXCR4-binding peptide, resulting in enhanced macrophage polarization to the antitumoral M1 phenotype characterized by proinflammatory cytokine release. The manganese/doxorubicin-loaded hybrid vesicles in the CXCR4-expressing tumor cells evoked potent cancer cytotoxicity, immunogenic cell death of tumor cells, and STING activation. Moreover, cotreatment with manganese and doxorubicin promoted dendritic cell maturation, enabling effective tumor growth inhibition. In murine models of CT26 colon carcinoma and 4T1 breast cancer, intravenous administration of the manganese/doxorubicin-loaded hybrid vesicles elicited robust tumor-suppressing activity at a low dosage without adverse systemic effects. Local administration of hybrid nanovesicles also induced an abscessive effect in a bilateral 4T1 tumor model. This study demonstrates a promising biomimetic manganese/doxorubicin-based hybrid nanovesicle platform for effective cancer immunotherapy tailored to the tumor microenvironment, which may offer an innovative approach to combinatorial immunotherapy.

Abstract 1377: The role of TIM3 and PD1 blockades in head and neck cancer

Abstract Background: Our group has recently developed and validated a novel prognostic score for human papillomavirus (HPV+) oropharyngeal cancer called UWO3, which stratifies patients into low risk (immune rich), intermediate risk (immune mixed), and high risk (immune desert) groups. The high-risk immune desert group had a paucity of immune cells, however, that population of lymphocytes expressed high levels of the checkpoint molecule TIM3. To follow up on this, we assessed the therapeutic effect of anti-TIM3 mAb alone and in combination with anti-PD-1 in a syngenic murine HPV+ head and neck cancer model using the mERR. T-cell immunoglobulin mucin 3 (TIM3) and Programmed death 1 (PD-1) are negative immune checkpoint receptors that are expressed on tumor-infiltrating lymphocytes (TIL), play a crucial role in tumor-induced immune suppression. Given the critical role that the tumour microenvironment (TME) has on the prognosis of head and neck squamous cell carcinoma (HNSCC), immune checkpoint inhibitor immunotherapy approaches, specifically anti-PD1 and/or anti-TIM3 antibody therapy, may be very effective treatment strategies and may offer improved survival outcomes. Methods:Immunocompetent C57BL/6 mice were injected in one flank with the syngeneic mouse HPV+ cell line, mEERL (106 cells), for tumour generation. Mice were then treated with either IgG2a isotype control, anti-PD1 (200μg), anti-TIM3 (200 μg) antibodies or a combination of anti-PD-1 and anti-TIM3 were administered via intraperitoneal injection 3 times per week following tumour establishement for 6 weeks (n = 7 mice per arm, total of 28 mice). Tumour volumes were measured every 2 days. Three representative tumors from each treatment group were collected for bulk RNA sequencing, scRNA-seq, and flow cytometry to characterise immune cell populations and transcriptional changes and monitor their impact on the TME of HNSCC. Results:Anti-PD1 and anti-TIM3 both restricted tumour growth by size and weight relative to the IgG2a control (p<0.01, linear mixed model [lmm]). The combination of anti-PD1 and anti-TIM3 was more effective than either monotherapy alone (p<0.05, lmm). RNA sequencing analysis revealed differential abundance in CCL6, CCL9, CFD, and MAP3K5 transcripts relative to control for anti-PD1, anti-TIM3, and combination checkpoint inhibition. Conclusion:Targeting both PD-1 and TIM3 enhanced the anti-tumor immune response in HPV+ head and neck tumours, providing further support for dual targeting of these molecules for more effective cancer immunotherapy. Our results suggest that immune checkpoint inhibitor therapy (PD1 and TIM3 blockades) could be a promising treatment strategy for HPV+ HNSCC, and the expression of these immune checkpoint molecules could serve as a predictive biomarker of patient outcome in HPV+ HNSCC. Citation Format: Mushfiq Shaikh, Amir Karimi, Peter Zeng, Harrison Pan, John Barrett, Anthony Nichols. The role of TIM3 and PD1 blockades in head and neck cancer [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 1377.

Abstract 3187: Enhancing STING activation by cyclic dinucleotide-manganese particles for systemic cancer immunotherapy

Abstract Background: Activating the innate immune pathway of stimulator of interferon genes (STING) can elicit potent anti-tumor immunity via the production of type-I interferons (IFN-I). However, cyclic-dinucleotide (CDN) STING agonists have undesirable pharmacological properties. Most CDNs in clinical development are administered intratumorally, thus precluding their utility against advanced cancer. Here, we report the development of a new nanoparticle system for the systemic delivery of CDN STING agonists with potent efficacy, favorable pharmaceutical properties, and acceptable safety profiles. Methods: Various metal ions were screened for synergy with CDNs for IFN-I response from bone marrow-derived dendritic cells. Lipid nanoparticles carrying CDN and manganese ions (termed SNP) were synthesized. Mice bearing syngenetic tumors (including CT26 and B16F10) as well as genetically engineered mouse models were treated by intravenous administration of SNP, followed by tumor monitoring and immune profiling of the tumor microenvironment. White New Zealand rabbits bearing VX2 tumors as well as healthy mongrel dogs were treated with SNP and evaluated. Lastly, human tumor biopsies derived from head and neck squamous cell carcinoma (HNSCC) patients were incubated with SNP or soluble STING agonists and analyzed for immune activation. Results: We identified that Mn2+ achieved strong synergy with CDN STING agonists for inducing IFN-I production. SNP carrying CDN and Mn2+ was dosed intravenously in mice, leading to robust IFN-I response, remodeling of the immunosuppressive tumor microenvironment, and expansion of anti-tumor CD8+ T cells. Intravenous SNP therapy resulted in robust anti-tumor efficacy in multiple murine tumor models, including CT26, B16F10, and a genetically engineered mouse model of MMTV-PyMT triple-negative breast cancer. We have also observed robust anti-tumor efficacy of SNP against VX2 squamous carcinomas in rabbits and have demonstrated the safety of intravenous SNP therapy in healthy dogs. Mechanistically, the efficacy of SNP therapy was dependent on the host STING expression but independent of the tumor STING expression. In addition, the anti-tumor efficacy of SNP was decreased in mice lacking Ifnar1 or Ifngr1 expression in the B16F10 melanoma model, showing the crucial effects of IFN-I and IFN-II responses. Moreover, SNP treatment led to robust IFN-I responses from fresh human tumor biopsies derived from HNSCC patients. Conclusions: SNP empowers highly effective systemic cancer immunotherapy via nanotechnology. It also underscores the potential of utilizing metal ions for immune-mediated disease treatment. Citation Format: Xingwu Zhou, Xiaoqi Sun, Wang Gong, Ziye Wan, Teresa Krieger-Burke, Vilma Yuzbasiyan-Gurkan, Yu Leo Lei, James Moon. Enhancing STING activation by cyclic dinucleotide-manganese particles for systemic cancer immunotherapy [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 3187.

Abstract 3735: Combinatorial targeting of tumor-microenvironment together with antigen vaccination using innovative nano-immuno-gel for enhanced cancer-immunotherapy

Abstract Successful cancer-immunotherapy need to address three critical factors: a) Relieving the immuno-suppressive tumor microenvironment (TME) b) expanding antigen specific, functionally avid effector T cells, c) triggering systemic immunity with a balanced innate-adaptive response for continued effector cell-feeder supply-chain and memory generation. Combinatorial engagement of such multi-elemental components demands smart, engineered immunotherapy systems compared to conventional vaccines. Here, we report an injectable Nano-Immuno-Gel (NIG) that can neutralize immunosuppressive components (e.g., myeloid derived suppressor cells (MDSCs), M2 macrophages (Mϕ) in TME, together with generating strong effector T cells by nano-vaccination, and sustained release of cytokines to enhance systemic immunity against tumor. In a proof-of-concept study, we show that sustained-release of myeloid-suppressive drug from NIG depot efficiently inhibited MDSCs and M2 Mϕ, not only in TME, but also in the circulation and in peripheral systems, thus creating a conducive, hot TME infiltrated with CD8 effector cells. Follow-up antigen vaccination with novel nano-adjuvant enhanced DC-T cell engagement and sustained IL15 release from NIG provided systemic NK/T cell activation, rendering significant control of the tumor growth. Our data demonstrate the potential of rationally engineered multi-functional nano-immuno-gels (NIG) to combine sequential neutralization of the suppressive TME, antigen vaccination, and concurrent systemic immune activation for highly effective combinatorial cancer immunotherapy. Citation Format: Anjali Kozhissery Sunilkumar, Margaux Salvi, Saira Nujoom Mohammed, Zahara Thaivalappil Zakkariya, Alejandra Gomez Cadena, Shalin Chappan, Sreedevi Panachithanathu Radhakrishnan, Maneesh Manohar, Pavithran Keechilat, Shantikumar Nair, Pedro Romero, Camilla Jandus, Manzoor Koyakutty. Combinatorial targeting of tumor-microenvironment together with antigen vaccination using innovative nano-immuno-gel for enhanced cancer-immunotherapy [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 3735.

Abstract 7392: Machine learning-based identification of H&E-derived morphologic features associated with CD8+ T cell immune exclusion

Abstract Background: Immune exclusion is characterized by a predominance of CD8+ T cells in the stroma of the tumor microenvironment (TME) which are not in contact with tumor cells. Immune exclusion is a significant obstacle to effective cancer immunotherapy and reversing it has emerged as a new therapeutic opportunity. However, the objective assessment of immune exclusion remains a challenge due to the complexity of the TME and the need for immunostaining to quantify CD8+ cells in tumor and stroma. While artificial intelligence (AI) models applied to H&E images can quantify spatial tissue and cell features at scale, they are unable to identify the molecular subtypes of cells. Here we describe the development of a machine learning model that classifies tumors by their CD8-defined immune phenotypes using features extracted from H&E whole slide images alone. Methods: Al-powered TME models (PathAI PathExplore™) were deployed on H&E images from 39 non-small lung cancer (NSCLC) and triple-negative breast cancer (TNBC) samples. CD8-based assessment of immune phenotypes was done using an adjacent section. 115 H&E-derived features from each of the 25 tumor samples (12 NSCLC, 13 TNBC) classified as immune excluded and 7 tumor samples (3 NSCLC, 4 TNBC) classified as immune infiltrated were used as input into a feature selection process to identify the subset of H&E features predictive of immune phenotype. The feature selection process was driven by an ensemble L1 norm support vector machine (Ens-L1-SVM) model containing 500 L1-SVM base models each trained by 80% of the data. The degree of immune exclusion was determined in the feature space by the distance to the separation hyperplane defined by the model. Out-of-bag error estimation was employed on the remaining 20% of data from each base model to assess model performance. Results: The Ens-L1-SVM model identified 6 H&E features predictive of CD8-defined immune phenotypes, including the density ratio of lymphocytes to macrophages in the cancer epithelium, the density of fibroblasts, and the spatial distributions of cancer cells, macrophages, and lymphocytes. Immune phenotypes were classified by the Ens-L1-SVM model with an estimated accuracy of 97%. Additionally, all selected features and their direction of association aligned with prior knowledge of the mechanisms or manifestations of immune exclusion or infiltration in the TME. Conclusion: This work illustrated that morphologic features derived from H&E images using AI-powered models can be effective predictors of CD8-defined immune exclusion, providing an option for patient stratification by immune phenotype using widely-available H&E images. While the Ens-L1-SVM model showed robust performance on a small number of samples and is expected to have good generalizability due to the linear nature of the model, additional validation across diverse datasets and various tumor indications is needed. Citation Format: Yanchao Wang, Fredrick D. Gootkind, Florent Peyraud, Jean-Philippe Guégan, Antoine Italiano, G. Travis Clifton, Laura A. Dillon, Xinwei Sher. Machine learning-based identification of H&E-derived morphologic features associated with CD8+ T cell immune exclusion [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 7392.

A self-cascade terpolymer platform for amplified chemo-chemodynamic therapy with synergistic immunogenic cell death enhancement

Chemodynamic therapy, which relies on the generation of cytotoxic radicals, can be amplified by a nanoplatform that produces hydroxyl radicals while also compromising natural radical scavenging mechanisms. For this purpose, a well-defined amphiphilic terpolymer, poly(oligo(ethylene glycol) monomethyl ether methacrylate)-block-poly(N,N-dimethyl aminoethyl methacrylate-statistical-monomer bearing ferrocene graft via azobenzene linker) (POEGMA-b-P(DMAEMA-st-(M-Azo-Fc), denoted as PAzo-Fc) is prepared by a consecutive reversible addition-fragmentation chain transfer (RAFT) polymerization technique, and is further used for doxorubicin (DOX) encapsulation to afford DOX-loaded stabilized nanomicelles, DOX@PAzo-Fc with an average hydrodynamic diameter of 86.0 nm. DOX@PAzo-Fc shows a self-cascade property for amplified CDT. That is, Azo cleavage-induced glutathione (GSH) depletion alleviates reactive oxygen species (ROS) scavenging. Together with the DOX-enhanced hydrogen peroxide generation, the Fc-mediated Fenton reaction is boosted for enhanced CDT. More importantly, the resulting amplified cascade chemo-chemodynamic therapy exerts a synergistic immunogenic cell death (ICD) enhancement effect for effective cancer immunotherapy, which further resulted in a high tumor inhibition rate of 87.8 % in murine tumor models. The uniqueness of this study is the construction of a minimalist nanoplatform based on M-Azo-Fc units for amplified CDT via simultaneously producing hydroxyl radicals and compromising natural radical scavenging mechanisms. Overall, this self-cascade terpolymer platform fabricated herein offers a facile yet robust approach for advanced combinatory cancer therapy with great potential for clinical translations.

Discovery of novel IDO1/TDO2 dual inhibitors: a consensus Virtual screening approach with molecular dynamics simulations, and binding free energy analysis

The pursuit of effective cancer immunotherapy drugs remains challenging, with overexpression of indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase 2 (TDO2) allowing cancer cells to evade immune attacks. While several IDO1 inhibitors have undergone clinical testing, only three dual IDO1/TDO2 inhibitors have reached human trials. Hence, this study focuses on identifying novel IDO1/TDO2 dual inhibitors through consensus structure-based virtual screening (SBVS). ZINC15 natural products library was refined based on molecular descriptors, and the selected compounds were docked to the holo form IDO1 and TDO2 using two different software programs and ranked according to their consensus docking scores. The top-scoring compounds underwent in silico evaluations for pharmacokinetics, toxicity, CYP3A4 affinity, molecular dynamics (MD) simulations, and MM-GBSA binding free energy calculations. Five compounds (ZINC00000079405/10, ZINC00004028612/11, ZINC00013380497/12, ZINC00014613023/13, and ZINC00103579819/14) were identified as potential IDO1/TDO2 dual inhibitors due to their high consensus docking scores, key residue interactions with the enzymes, favorable pharmacokinetics, and avoidance of CYP3A4 binding. MD simulations of the top three hits with IDO1 indicated conformational changes and compactness, while MM-GBSA analysis revealed strong binding free energy for compounds 10 (ΔG: −20.13 kcal/mol) and 11 (ΔG: −16.22 kcal/mol). These virtual hits signify a promising initial step in identifying candidates as supplementary therapeutics to immune checkpoint inhibitors in cancer treatment. Their potential to deliver potent dual inhibition of IDO1/TDO2, along with safety and favorable pharmacokinetics, makes them compelling. Validation through in vitro and in vivo assays should be conducted to confirm their activity, selectivity, and preclinical potential as holo IDO1/TDO2 dual inhibitors. Communicated by Ramaswamy H. Sarma

Abstract IA005: Regional combating of immunosuppressive forces in the ovarian tumor microenvironment

Abstract IA005: Regional combating of immunosuppressive forces in the ovarian tumor microenvironment

Radiation-based immunogenic vaccine combined with a macrophage “checkpoint inhibitor” for boosting innate and adaptive immunity against metastatic colon cancers

Immunogenic dying tumor cells hold promising prospects as cancer vaccines to activate systemic immunity against both primary and metastatic tumors. Especially, X-ray- induced dying tumor cells are rich in highly immunogenic tumor-associated antigens and self-generated dsDNA as potent adjuvants. However, we found that the X-ray induction process can result in the excessive exposure of phosphatidylserine in cancer vaccines, which can specifically bind with the MerTK receptor on macrophages, acting as a “checkpoint” to facilitate immune silence in the tumor microenvironment. Therefore, we developed a novel strategy combining X-ray-induced cancer vaccines with UNC2250, a macrophage MerTK “checkpoint inhibitor,” for treating peritoneal carcinomatosis in colon cancer. By incorporating UNC2250 into the treatment regimen, immunosuppressive efferocytosis of macrophages, which relies on MerTK-directed recognition of phosphatidylserine on vaccines, was effectively blocked. Consequently, the immune analysis revealed that this combination strategy promoted the maturation of dendritic cells and M1-like repolarization of macrophages, thereby simultaneously eliciting robust adaptive and innate immunity. This innovative approach utilizing X-ray-induced vaccines combined with a checkpoint inhibitor may provide valuable insights for developing effective cancer vaccines and immunotherapies targeting colon cancer.

Artificial Intelligence for Precision Oncology of Triple-Negative Breast Cancer: Learning from Melanoma.

Thanks to new technologies using artificial intelligence (AI) and machine learning, it is possible to use large amounts of data to try to extract information that can be used for personalized medicine. The great challenge of the future is, on the one hand, to acquire masses of biological data that nowadays are still limited and, on the other hand, to develop innovative strategies to extract information that can then be used for the development of predictive models. From this perspective, we discuss these aspects in the context of triple-negative breast cancer, a tumor where a specific treatment is still lacking and new therapies, such as immunotherapy, are under investigation. Since immunotherapy is already in use for other tumors such as melanoma, we discuss the strengths and weaknesses identified in the use of immunotherapy with melanoma to try to find more successful strategies. It is precisely in this context that AI and predictive tools can be extremely valuable. Therefore, the discoveries and advancements in immunotherapy for melanoma provide a foundation for developing effective immunotherapies for triple-negative breast cancer. Shared principles, such as immune system activation, checkpoint inhibitors, and personalized treatment, can be applied to TNBC to improve patient outcomes and offer new hope for those with aggressive, hard-to-treat breast cancer.

B10 cells: Development, phenotype, and function in cancer.

B10 cells, a specialized subset of regulatory B cells, have been identified in both mice and humans. These cells are characterized by their regulatory impact on immune dynamics, principally through their secretion of interleukin-10 (IL-10), a cytokine known for its anti-inflammatory properties. The pivotal role of immune mediators such as B10 cells is to maintain a delicate equilibrium between antitumor immunity and tumor-promoting responses. Emerging studies have cast B10 cells as key suppressors in the antitumor immune arsenal. They operate in synergy with a spectrum of immune cells within the innate and adaptive spectrums, contributing to a milieu that favors tumor progression and metastatic spread. In this comprehensive review, we will discuss the ontogeny, phenotype and effector functions of B10 cells in murine systems. We will also review the role of B10 cells in oncological models in animal studies and extend these findings to the human clinical context, elucidating their role in facilitating tumor immune evasion. A thorough understanding of these processes is imperative for the strategic targeting and attenuation of B10 cell activity, which is anticipated to be a cornerstone in the advancement of effective cancer immunotherapy strategies.

Impaired monocyte-derived dendritic cell phenotype in prostate cancer patients: A phenotypic comparison with healthy donors.

Dendritic cells (DCs) play a crucial role in immunity. Research on monocyte-derived DCs (Mo-DCs) cancer vaccines is in progress despite limited success in clinical trials. This study focuses on Mo-DCs generated from prostate cancer (PCA) patients, comparing them with DCs from healthy donors (HD-DCs). Mo-DCs were isolated from PCA patient samples, and their phenotype was compared to HD-DCs. Key parameters included monocyte count, CD14 expression, and the levels of maturation markers (HLA-DR, CD80, CD86) were assessed. PCA samples exhibited a significantly lower monocyte count and reduced CD14 expression compared to healthy samples (p ⟨ 0.0001). Additionally, PCA-DCs expressed significantly lower levels of maturation markers, including HLA-DR, CD80, and CD86, when compared to HD-DCs (p = 0.123, p = 0.884, and p = 0.309, respectively). The limited success of DC vaccines could be attributed to impaired phenotypic characteristics. These observations suggest that suboptimal characteristics of Mo-DCs generated from cancer patient blood samples might contribute to the limited success of DC vaccines. Consequently, this study underscores the need for alternative strategies to enhance the features of Mo-DCs for more effective cancer immunotherapies.

Abstract B046: Exploring the potential of commensal polyomavirus as a promising approach for breast cancer treatment

Abstract Cancer is a leading cause of mortality worldwide, accounting for nearly one in six deaths. Our understanding of the immune system role in cancer control has increased dramatically in recent decades, facilitating the recent development of effective cancer immunotherapies, which have significantly improved the survival of cancer patients. However, current immunotherapies can induce overactive immune responses with severe even fatal outcomes. Moreover, immunotherapy may not work in every scenario, especially in ‘cold’ tumors that lack immune cell infiltration. Thus, more effective immunotherapies with fewer side effects are under active investigation. Viruses are one of the most abundant biological entities in the world; about 12% to 20% of human cancers are associated with viral infections. Viral antigens can increase tumor immunogenicity, triggering T cell immunity against tumor cells. Polyomaviruses are small, nonenveloped double-stranded DNA viruses that are widespread. In immunocompetent hosts, polyomaviruses remain at a low persistent level in the host after the primary infection, which appears to cause little or no symptoms. Previous studies have shown high polyomavirus seroprevalence and the frequent presence of polyomavirus-specific T cells in healthy adult blood donors. In the elderly population, Merkel cell polyomavirus (MCPyV) infection is linked to Merkel cell carcinoma (MCC), a rare, aggressive skin cancer associated with immunosuppression. MCPyV integration into the genome is the primary oncogenic event in ~80% of MCC cases, and the remaining virus-negative MCC cases are associated with ultraviolet (UV) radiation. MCPyV-induced MCCs are associated with more intratumor immune cells and better responses to cancer therapy. Moreover, BK and JC polyomavirus positive lymphoma patients showed a trend toward significantly better overall survival. These clinical data suggest that polyomavirus in tumors may increase tumor immunogenicity. Thus, polyomavirus presents an intriguing opportunity to develop a novel strategy to enhance cancer immunogenicity. We utilized mouse polyomavirus (MPyV) to colonize typically ‘cold’ breast tumor cell line E0771 breast cancer cells in mice. MPyV infection blocked the growth of tumors in immunocompetent mice and promoted immune cell infiltration when intratumorally delivered to the tumor. The tumor rejection activity of polyomavirus is depend on CD4 and CD8 T cells. Unlike conventional oncolytic viruses which directly lyse the infected cells and trigger a nonspecific inflammatory response, polyomavirus does not lyse the colonized cells, and it induces a relatively low level of inflammation. Instead, polyomavirus stimulates viral antigen expression in tumors that boosts T cell response leading to epitope spreading to tumor-associated antigens. The outcomes of this research will establish the utility of commensal polyomavirus as a novel agent for cancer immunotherapy. Citation Format: YUN XIA. Exploring the potential of commensal polyomavirus as a promising approach for breast cancer treatment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr B046.

Nanoparticle-integrated dissolving microneedles for the co-delivery of R848/aPD-1 to synergistically reverse the immunosuppressive microenvironment of triple-negative breast cancer

Nowadays, effective immunotherapy against triple-negative breast cancer (TNBC) remains challenging due to the immunosuppressive tumor microenvironment. Immune checkpoint inhibitor is mostly employed to restore the activity of tumor-specific immune cells, which however brings little therapeutic outcome owing to the limited number of tumor-infiltrating CD8+ T cells and the inefficient delivery of immune drugs to the tumor tissue. Aiming to solve these problems, we herein constructed a tailor-made dissolving microneedle co-encapsulating the TLR7/8 agonist R848 and the immune checkpoint inhibitor aPD-1, termed αNP-RNP@DMN, and fabricated it as a transdermal drug delivery system. This well-designed microneedle patch, endowed with efficient tumor drug delivery ability, was able to mature tumor-infiltrating dendritic cells (TIDCs) and further promote the infiltration of CD8+ T cells into the tumor tissue with the aid of R848. Moreover, the introduction of aPD-1 blocked the programmed cell death protein 1/programmed cell death ligand 1(PD-1/PD-L1) immune checkpoints, synergistically reversing the immunosuppressive microenvironment of TNBC. In vivo therapeutic results demonstrated that αNP-RNP@DMN not only significantly prolonged the survival time of 4T1 tumor-bearing mice, but also inhibited tumor recurrence and lung metastasis after surgery, implying the great potential of this effective drug delivery system for enhanced immunotherapy of superficial tumors. Statement of significanceThe limited number of tumor-infiltrating CD8+ T cells and the inefficient delivery of immune drugs to the tumor tissue hinder the effective immunotherapy of triple-negative breast cancer (TNBC). Herein, a dissolving microneedle co-encapsulating TLR7/8 agonist R848 and immune checkpoint inhibitor aPD-1 was developed and fabricated as a transdermal drug delivery system. This tailor-made microneedle patch not only promoted drug accumulation in tumor sites in a safe and painless manner, but also lifted the immune-suppressive state of tumor-infiltrating dendritic cells (TIDCs). The activated TIDCs further enhanced T-cell infiltration into the tumor tissue, thus successfully boosting the therapeutic efficacy of aPD-1. This study demonstrated that this well-designed microneedle patch could be served as an effective drug delivery system for enhanced immunotherapy of TNBC.

Molecular Masking of Synthetic Immunomodulator Evokes Antitumor Immunity With Reduced Immune Tolerance and Systemic Toxicity by Temporal Activity Recovery and Sustained Stimulation.

Activation of the innate immune system counteracts tumor-induced immunosuppression. Hence, small molecule-based toll-like receptor 7/8 agonists (TLR7/8a), which can modulate immunosuppression in the tumor microenvironment along with the activation of innate immunity, are emerging as essential components of cancer immunotherapy. However, the clinical application of synthetic TLR7/8a therapies is limited by systemic immune-associated toxicity and immune tolerance induced by uncontrolled stimulatory activities and repeated treatments. To address these limitations, a dynamic immunomodulation strategy incorporating masking and temporal recovery of the activity of TLR7/8a through prodrug-like TLR7/8a (pro-TLR7/8a) at the molecular level and a sustained and controlled release of active TLR7/8a from nanoliposome (pro-TLR7/8a) (NL(pro-TLR7/8)) in a macroscale depot are designed. Immunization with cationic NL(pro-TLR7/8) and anionic antigens triggers robust activation of innate immune cells as well as antigen-specific T cell responses, eliciting reprogramming of immunosuppressive cells into tumor-suppressive cells, with decreased systemic adverse effects and immune tolerance. Combination treatment with NL(pro-TLR7/8a) and immune checkpoint inhibitors (anti-CTLA-4 plus anti-PD-L1) or nanoliposomes (Doxorubicin) has synergistic effects on antitumor immunity in various tumor models. The concept of pro-TLR7/8a suggested herein may facilitate the advancement of small-molecule-based immunomodulators for clinical translation and safe and effective cancer immunotherapy.