Tumor-specific Immune Responses Research Articles

Heterologous prime-boost vaccine using antigen-loaded microparticles and adenovirus (encoding antigen) enhances cellular immune responses and antitumor activity

Heterologous prime-boost vaccines have the potential to promote higher immune responses than homologous prime-boost vaccines and were used in this murine study to investigate the effect on the magnitude of the cellular (and humoral) antigen-specific immune responses and antitumor efficacy when a microparticle formulation (prime) is combined with an adenoviral vaccine (boost). Specifically, the prime comprised chick egg ovalbumin (OVA; 25 µg/dose), used here as a model tumor antigen (TA), encapsulated in microparticles (∼700 nm diameter) made from the biodegradable polymer, 50:50 poly(lactic-co-glycolic acid) (PLGA); while attenuated adenovirus (type 5) encoding OVA (Ad5OVA; 108 PFU/dose) was employed as the boost. The ability of OVA-loaded microparticles to enhance OVA-specific antibody responses, OVA-specific CD3 + CD8 + T cell responses and antitumor activity (i.e., protection against OVA-expressing tumor-challenge) to the heterologous prime-boost vaccine was investigated; and it was found that this prime-boost combination could significantly enhance OVA-specific cellular responses compared to all other vaccination groups and was the only group to confer a significant survival advantage over the unvaccinated group (naïve) in a prophylactic animal tumor model. This finding illustrates the potential for combining TA-loaded PLGA-based microparticles with other vaccine formats to improve tumor-specific cellular immune responses.

Abstract 6543: Comparative analysis of immune landscape according to EGFR mutation and tumor PD-L1 proportion scores in non-small cell lung cancer at single cell resolution

Abstract Introduction: In EGFR-mutant non-small cell lung cancer (NSCLC), the efficacy of immune checkpoint blockade (ICB) is limited with higher incidence of toxicity profiles. EGFR-mutant NSCLC is associated with immune suppressive microenvironment, including lower programmed death-ligand 1 (PD-L1), tumor mutational burden (TMB), and tumor-infiltrating CD8+ T lymphocytes. However, tumors expressing high levels of PD-L1 show improved and durable clinical benefit in immunotherapy. In addition, Understanding the dynamics of tumor microenvironment may elucidate immune response in terms of immune composition, and help overcome resistance to immune checkpoint inhibitors. Here, we demonstrate that conventional type 1 dendritic cells (cDC1s) is one of the key tumor microenvironment, resulting in priming of CD8+ T cells and production of chemokines, such as CXCL9/CXCL10 and cytokines that augment anti-tumor immunity. Methods: A total of 31 surgical samples of NSCLC, including EGFR wild and mutant NSCLC of stages I-III, and 16 normal lung tissue samples were collected. PD-L1 expression in EGFR wild type was categorized into tumor proportion score (TPS) of < 50% and ≥ 50% using immunohistochemistry (IHC). Single cell RNA sequencing was performed with the Scanpy toolkit on the retrospective cohorts of normal (n=16), EGFR mutant (n=14, L858R=6, E19Del=8), EGFR wild TPS ≥ 50% (n=10), and TPS < 50% (n=7). Results: We observed that an overall tumor specific immune response occurred in EGFR wild-type TPS ≥ 50% compared with others. XCL1+ innate-like T cells, which act as an orchestra of tumor specific immune response, were found. These cells had high expression of FCER1G and IL2RB, a receptor for IL-15, However, expression of CD8A/B, CD4 and FCGR3A was low. Interestingly, in these innate-like T cells, the expression of ITGAE, which interacts with E-cadherin in cancer cells, and CD81, which interacts with CD3 and enhances immunological synapse, was observed in EGFR wild TPS ≥ 50%. According to these results, XCR1+ cDC1s were enriched in EGFR wild-type TPS ≥ 50%. CXCL9/CXCL10, which recruits CXCR3+ effector T cells which are primed at the lymph node, was highly expressed in activated DCs at EGFR wild TPS ≥ 50%. CD8+ T cells were significantly enriched in EGFR wild-type TPS ≥ 50%. These cells also expressed IFNG and FLT3LG, which maintain the function of intra-tumoral dendritic cells (DCs), and were also up-regulated in EGFR wild-type TPS ≥ 50%. Among them, exhausted CD8+ T cells expressing PDCD1 were observed in EGFR wild TPS ≥ 50%, and these cells also expressed ITGAE and CD81. In addition, these cells also showed high expression of CXCR3, a receptor for CXCL9/CXCL10 which were expressed in the activated DCs. Conclusion: cDC1s-mediated tumor specific immune response occurred in patients with EGFR wild TPS ≥ 50%, which could be an important mechanism to predict anti-PD-1 response. Citation Format: YoungJoon Park, Su-Jin Choi, Jii Bum Lee, Dong Kwon Kim, Sun Min Lim, Seong Gu Heo, Ke Jia Qi, Byoung Chul Cho, Kyoung-Ho Pyo. Comparative analysis of immune landscape according to EGFR mutation and tumor PD-L1 proportion scores in non-small cell lung cancer at single cell resolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6543.

Abstract 6399: Hyperthermic intrathoracic chemotherapy (HITOC) improves malignant pleural mesothelioma control through a tumor specific cytotoxic immune response

Abstract Introduction: The management of malignant pleural mesothelioma (MPM) remains challenging with poor patient survival. Local therapies such as hyperthermic intrathoracic cisplatin (HITOC) have shown good tumor control in selected patients. HITOC was shown to increase MPM drug exposure while limiting systemic side effects but alternative mechanisms for HITOC are still lacking. Here, we hypothesized that HITOC induces an immune response directed against MPM which decreases cancer related mortality. Methods: We implanted AB12-luc MPM cells in the pleural cavity of BALB/c mice. A chemotherapy perfusion circuit was downsized to administer cisplatin (80mg/m2 equivalent dose) in the thoracic cavity at normo (37°C, ITOC) or hyperthermic (39°C, HITOC) conditions for 30 minutes. Tumor growth (visualized by bioluminescence) and mouse survival were then assessed. We determined tumor platinum content and distribution by inductively coupled plasma mass spectrometry (ICP-MS) and by laser ablation ICP-MS (LA-ICP-MS) respectively. We also questioned the impact of (H)ITOC on the MPM immune microenvironment (innate and adaptive immune cells, activity and checkpoint expression) by 16-colour flow cytometry and immunohistochemistry. Finally, tumor response to (H)ITOC was assessed in BALB/c athymic mice implanted with AB12-luc cells. Results: MPM tumor control and mouse survival were significantly improved by HITOC compared to controls (ITOC, saline 37 and 39°C). Tumor platinum content was significantly higher in HITOC compared to ITOC but was majorly located at the surface of tumors. HITOC enhanced MPM infiltration by CD8+Granzyme B+ T-cells and decreased the levels of MCHII−/CD80− (M2-like) macrophages compared to controls at day 7. Interestingly, immune checkpoint expression of PD1 and CTLA4 was significantly enhanced in CD8+ lymphocytes in HITOC treated MPM compared to controls at day 7. Finally, the lack of T lymphocytes (BALB/c athymic mice) abrogated the impact of HITOC on MPM control and mouse survival. Conclusion: HITOC improves MPM control through a T lymphocyte immune mediated response. The enhanced immune checkpoint (PD1/CTLA4) expression in CD8+ lymphocytes opens perspectives for the combination of HITOC with immune checkpoint inhibitors. Citation Format: Yameng Hao, Aspasia Gkasti, Louis-Emmanuel Chriqui, Damien Marie, Michel Gonzalez, Thorsten Krueger, Solange Peters, Paul J. Dyson, Etienne Meylan, Johanna Joyce, Sabrina Cavin, Jean Y. Perentes. Hyperthermic intrathoracic chemotherapy (HITOC) improves malignant pleural mesothelioma control through a tumor specific cytotoxic immune response. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6399.

Abstract 6638: Pulsed electric fields combined with anti-PD1 prolongs survival and triggers an adaptive immune response in an IO-non-responsive orthotopic mouse model

Abstract Background: Although anti-PD1 therapy is standard of care in multiple tumor types, unmet need remains for those non-responsive to immunotherapy. Pulsed Electric Field (PEF) treatment may alter the tumor micro-environment, converting an immune “cold” tumor into an immune “hot” tumor, triggering an adaptive immune response and abscopal effect. We evaluated PEF in combination with anti-PD1 in a highly aggressive orthotopic triple negative breast tumor mouse model. Methods: Murine mammary 4T1 cells (2 × 105) non-responsive to anti-PD1 therapy were orthotopically implanted in mammary fat of 48 female Balb/C mice. Once tumors were established (5 mm diameter), mice were randomized into six groups: Sham+IgG controls, aPD-1-only, PEF (1X), PEF (2X), aPD-1 + PEF (1X), and aPD-1 + PEF (2X). Groups 4 and 6 received two PEF treatments, five days apart. Anti-PD1 and isotype matched control IgG was administered (200 ug, intraperitoneal) weekly, starting 3 days after PEF treatment. Tumor volumes were recorded 3x/week and standard survival analyses were conducted per IACUC protocol. In the cohort of tumors collected 30 days after PEF, flow cytometry (FC) evaluated T-cell immune infiltrates and associated markers. Blood was collected at different time points to evaluate systemic immunological response. Tumor-specific cytotoxic lymphocytes (CTL) were isolated from tumor-infiltrating and circulating lymphocytes by gp70 MHC tetramer formation assay. Results: Single PEF reduced tumor growth compared to IgG and aPD-1-only groups by 65% and 62%, respectively. Double PEF treatment reduced tumor growth by 74% and prolonged survival. FC demonstrated circulating helper T-cells and CTL frequency was increased two weeks post-PEF compared to the control group. The tetramer detected substantial increases in antigen-specific T-cell populations in both single and double PEF treatment groups. PEF groups had significant tumor and spleen infiltration of CD8 and CD4 T-cells, including increased tetramer levels. Anti-PD1-only animals showed no meaningful reductions in tumor growth, prolonged survival, or significant changes in CD8, CD4 T cells or in the tetramer assay. Conclusions: PEF treatments prior to initiation of anti-PD1 in orthotopic 4T1 mouse model triggers a tumor-specific adaptive immune response in an immune “cold” tumor model, irrespective of anti-PD-1 therapy. PEF increases circulating and tumor-infiltrating T-cells and antigen-specific T-cells, with these effects observed after a single or two treatments with PEF. Collectively, our results demonstrate that PEF treatment prior to initiation of anti-PD1 treatment can reduce tumor growth, prolong survival, and activate an adaptive immune response in an immune “cold” tumor. These findings suggest that PEF treatment merits further evaluation in IO-non-responsive cancer patients. Citation Format: Ebtesam Nafie, Mukta Wagh, Chiara Pastori, Mo Trikha, Robert Neal. Pulsed electric fields combined with anti-PD1 prolongs survival and triggers an adaptive immune response in an IO-non-responsive orthotopic mouse model. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6638.

Abstract 691: Irradiated whole tumor cells pulsed with mannan-BAM, TLR ligands and anti-CD40 antibody serve as a potent tumor cell vaccine against glioblastoma

Abstract Despite numerous therapeutic advances in cancers, the treatment of glioblastoma multiforme (GBM) remains a challenge. Boosting T-lymphocyte mediated responses against GBM offers a promising approach towards solving this problem. Herein, we present a therapeutic vaccination strategy that promotes the phagocytosis of tumor cells, enhances tumor antigen presentation, and induces a tumor-specific adaptive immune response with subsequent tumor eradication. This strategy consists of subcutaneous injection of irradiated whole tumor cells (rWTC) pulsed with phagocytic agonists (Mannan-BAM), TLR ligands (LTA, Poly (I:C), and R-848), and anti-CD40 agonistic antibody (collectively abbreviated as rWTC-MBTA). We evaluated the therapeutic efficacy of rWTC-MBTA strategy in mouse syngeneic GBM tumor models with GL261 and SB28 cells. In GL261 GBM model, complete regression (CR) of intracranial tumors was achieved in 70% (7/10) of rWTC-MBTA treated animals while none survived in the control group. Of note, the therapeutic efficacy of rWTC-MBTA was abolished in CD4-T and/or CD8-T lymphocyte depleted mice. Immunophenotyping analyses of peripheral lymph nodes and brain tumors of rWTC-MBTA treated mice demonstrated increased antigen presenting cells (dendritic cells and MHC II+ monocytes) and increased cytotoxic IFNγ, TNFα, and granzyme B-secreting CD4-T and CD8-T cells. All three CR mice that were rechallenged with GL261 cells intracranially 14 months after their last rWTC-MBTA treatment resisted tumor development, confirming the establishment of long-term immunological memory. In SB28 GBM model, 80% (8/10) rWTC-MBTA treated mice survived past 95 days after tumor cell implantation without any GBM-related symptoms, with median survival being only 35 days in control groups. In summary, our study demonstrated that rWTC-MBTA strategy can induce potent adaptive immune response against GBM in pre-clinical models. Citation Format: Herui Wang, Rogelio Medina, Juan Ye, Samik Chakraborty, Ondrej Uher, Mitchell Sun, Jan Zenka, Mark R. Gilbert, Karel Pacak, Zhengping Zhuang. Irradiated whole tumor cells pulsed with mannan-BAM, TLR ligands and anti-CD40 antibody serve as a potent tumor cell vaccine against glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 691.

Abstract 3281: GEN1042 (DuoBody-CD40x4-1BB)®in combination with PD-1 blockade reverses T-cell exhaustion in vitro

Abstract GEN1042 (DuoBody®-CD40x4-1BB) is an investigational, novel, agonistic, bispecific antibody that combines targeting and conditional activation of CD40 and 4-1BB on immune cells for priming and (re-) activation of tumor-specific immune responses. We previously showed that GEN1042 induces conditional CD40 and 4-1BB agonist activity, leading to dendritic-cell maturation and enhanced T-cell activation and effector functions in vitro. However, dysfunction of exhausted T cells in the solid tumor microenvironment may represent a potential resistance mechanism to checkpoint inhibitors/agonists. Here we utilized a multi-omics approach to evaluate whether GEN1042 could reverse T-cell exhaustion in vitro. Publicly available single cell RNA sequencing datasets were harmonized across multiple solid-tumor indications (including treatment-naïve and anti-PD-1 and/or anti-CTLA-4 pretreated samples) and analyzed for expression of CD40, 4-1BB and PD-1 on various immune-cell subsets based on their transcriptomic signatures to characterize target prevalence. In vitro mixed lymphocyte reaction (MLR) functional assays were performed where unstimulated healthy donor CD3+ T cells or CD3+ T cells exhausted by repeated stimulation with anti-CD3/CD28 beads were co-cultured with allogeneic lipopolysaccharide (LPS)-matured dendritic cells. Cultures were analyzed for cytokine secretion and expression of cell surface proteins. In the unstimulated T cell/mDC MLR assay, concurrent treatment with GEN1042 and PD-1 blockade potentiated IFNγ, TNFα and IL-2 production compared with either compound alone. In the T-cell exhaustion MLR assay, T cells showed increased expression of inhibitory receptors (e.g., TIM-3, LAG-3) and exhibited hyporesponsiveness for both proliferation and cytokine secretion upon restimulation with anti-CD3/CD28 beads. Here, the combined functional effect of GEN1042 plus PD-1 blockade further potentiated IFNγ secretion compared to single agent activity and induced IL-2 at similar levels to that observed for GEN1042 alone. These data suggest that, in addition to enhancing T-cell effector functions during T cell priming, GEN1042 can amplify the magnitude of the immune response in combination with PD-1 blockade by re-establishing the functional activity of dysfunctional T cells. GEN1042 is currently being evaluated in patients with advanced solid tumors in a phase 1/2 clinical trial (NCT04083599). Citation Format: Vanessa M. Spires, Gregg Masters, Christina Yu, Matt Hancock, Monique N. Luijten, Alexander Muik, Kristina Nuermberger, Friederike Gieseke, Tahamtan Ahmadi, Özlem Türeci, Maria Jure-Kunkel, Ugur Sahin, Mark Fereshteh, Homer C. Adams, Jordan M. Blum. GEN1042 (DuoBody-CD40x4-1BB)®in combination with PD-1 blockade reverses T-cell exhaustion in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3281.

Abstract 2736: Locoregional modified vaccinia ankara (MVA) encoding a single-chain IL-12 achieves efficacy antitumor immune response in peritoneal carcinomatosis

Abstract Peritoneal carcinomatosis is an advanced stage of cancer developed in the peritoneal cavity without effective treatment. In order to restore antitumor immunity subverted by tumor cells, we evaluated in this study intraperitoneal administration of vaccinia virus Ankara (MVA) genetically modified to express the proinflammatory cytokine single-chain interleukin 12. MVA encoding scIL-12 was evaluated in peritoneal carcinomatosis models based on intraperitoneal administration of tumor cells. The immune response was evaluated by ELISpot, flow cytometry, intravital microscopy, and depleting monoclonal antibodies. Safety was assessed by measuring body weight and a hemogram test. Tissue tropism after intravenous or intraperitoneal administration was determined by bioluminescence analysis after the administration of MVA encoding luciferase. Intraperitoneal or locoregional administration, but not other routes of administration, elicited a potent immune response characterized by increased levels of tumor-specific T CD8 lymphocytes. The antitumor immune response was detectable not only in the peritoneal cavity but also systemically. As a result, a single intraperitoneal administration of MVA encoding scIL-12 completely eradicates MC38 cells implanted in the peritoneum, protecting cured mice from a subcutaneous rechallenge with MC38 cells. The safety profile of intraperitoneal administration was also superior to that of intravenous administration since there was no weight loss or hematological toxicity when the vector was infused into the peritoneal cavity. In conclusion, intraperitoneal administration of MVA vectors encoding scIL-12 induces a potent tumor-specific immune response that leads to the eradication of peritoneal metastasis. Citation Format: Ángela Bella, Leire Arrizabalaga, Claudia Augusta Di Trani, José González-Gomariz, Assunta Cirella, Irene Olivera, Maite Alvarez, Álvaro Teijeira, Cigdem Atay Langbein, José Medina-Echeverz, Maria Hinterberger, Hubertus Hochrein, Ignacio Melero, Pedro Berraondo, Fernando Aranda. Locoregional modified vaccinia ankara (MVA) encoding a single-chain IL-12 achieves efficacy antitumor immune response in peritoneal carcinomatosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2736.

Abstract 6340: Preclinical development of a monoclonal antibody targeting CD24 as cancer immunotherapy

Abstract CD24 is a novel immune checkpoint that suppresses activation of macrophages, natural killer (NK) cells, T cells and B cells by binding to inhibitory receptor Siglec-10. CD24 is highly expressed on cancers of genitourinary (GU) and gastrointestinal (GI) systems, breast, and lung. High expression of CD24 is also known to be associated with poor prognosis for many types of cancers including breast, lung, GU and GI systems, bone, skin and brain. Mouse models of breast and lung cancer in literature revealed that CD24 attenuation in vivo leads to tumor inhibition and prolonged survival. To address the limited (~25%) overall response rate (ORR) of approved PD-1/PD-L1 antibodies for solid tumors, we developed IMM47, an IgG1 antibody that differentially targets phagocytosis and cytotoxicity onto CD24-expressing cancer cells. At doses between 3 mg/kg to 10mg/kg, IMM47 significantly reduced tumor volume in a MC38 mouse model of colon cancer. Mice treated with 10mg/kg IMM47 produced tumor-specific immune response that prevented growth of re-inoculation of colon cancer cells. Further mechanism of action studies showed that IMM47 selectively and differentially increased M1 spleen macrophages quantity to 7-10 folds higher in that induced by PBS control. In contrast, IMM47 only increased M2 spleen macrophages to less than 1.5 folds higher than induced by PBS control. Expression of MHC II in M1 macrophages was also increased in IMM47-treated mice, suggesting significant activation and antigen presentation by macrophages. Our data has also confirmed that IMM47 specifically binds to and induces ADCC (antibody-dependent cellular cytotoxicity),ADCP (antibody-dependent cellular phagocytosis), and CDC (complement-dependent cytotoxicity) against a variety of cancer cells. Taken together, our data show that targeting CD24 on tumor cells using our IMM47 antibody may serve as potent immunotherapy for multiple cancer indications. Citation Format: Wenzhi Tian, Song Li, Dianze Chen, Dandan Liu, Huiqin Guo, Chunmei Yang, Li Zhang, Wei Zhang, Xiaoping Tu, Liang Peng, Gui Zhao, Ruliang Zhang, Fan Zhang, Frank X. Gan. Preclinical development of a monoclonal antibody targeting CD24 as cancer immunotherapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6340.

NIR-II light evokes DNA cross-linking for chemotherapy and immunogenic cell death.

As a DNA damaging agent, oxaliplatin (OXA) can induce immunogenic cell death (ICD) in tumors to activate the immune system. However, the DNA damage induced by OXA is limited and the ICD effect is not strong enough to enhance anti-tumor efficacy. Here, we propose a strategy to maximize the ICD effect of OXA through the mild hyperthermia generated by nanoparticles with a platinum (IV) prodrug of OXA (Pt(IV)-C16) and a near-infrared-II (NIR-II) photothermal agent IR1061 upon the irradiation of NIR-II light. The mild hyperthermia (43°C) holds advantages in two aspects: 1) increase the Pt-DNA cross-linking, leading to enhanced DNA damage and apoptosis; 2) induce stronger ICD effects for cancer immunotherapy. We demonstrated that, compared with OXA and photothermal therapy of IR1061 alone, these nanoparticles under NIR-II light irradiation can significantly improve the anti-cancer efficacy against triple-negative breast cancer 4T1 tumor. This new strategy provides an effective way to improve the therapeutic outcome of OXA. STATEMENT OF SIGNIFICANCE: OXA could induce immunogenic cell death (ICD) via stimulating immune responses by increasing tumor cell stress and death, which triggers tumor-specific immune responses to achieve immunotherapy. However, due to the insufficient Pt-DNA crosslinks, the ICD effect triggered by OXA cannot induce robust immune response. Mild hyperthermia has great potential to maximize the therapeutic outcome of oxaliplatin by increasing the Pt-DNA cross-linking to augment the immunoresponse for enhanced cancer immunotherapy.

A photoactive injectable antibacterial hydrogel to support chemo-immunotherapeutic effect of antigenic cell membrane and sorafenib by near-infrared light mediated tumor ablation.

Intravenously administered nanocarriers suffer from off-target distribution, pre-targeting drug leakage, and rapid clearance, limiting their efficiency in tumor eradication. To bypass these challenges, an injectable hydrogel with time- and temperature-dependent viscosity enhancement behavior and self-healing property are reported to assist in the retention of the hydrogel in the tumor site after injection. The cancer cell membrane (CCM) and sorafenib are embedded into the hydrogel to elicit local tumor-specific immune responses and induce cancer cell apoptosis, respectively. In addition, hyaluronic acid (HA) coated Bi2S3 nanorods (BiH) are incorporated within the hydrogel to afford prolonged multi-cycle local photothermal therapy (PTT) due to the reduced diffusion of the nanorods to the surrounding tissues as a result of HA affinity toward cancer cells. The results show the promotion of immunostimulatory responses by both CCM and PTT through the release of inflammatory cytokines from immune cells, which allows localized and complete ablation of the breast tumor in an animal model by a single injection of the hydrogel. Moreover, the BiH renders strong antibacterial activity to the hydrogel, which is crucial for the clinical translation of injectable hydrogels as it minimizes the risk of infection in the post-cancer lesion formed by PTT-mediated cancer therapy.

Engineered tumor cell-derived vaccines against cancer: The art of combating poison with poison.

Tumor vaccination is a promising approach for tumor immunotherapy because it presents high specificity and few side effects. However, tumor vaccines that contain only a single tumor antigen can allow immune system evasion by tumor variants. Tumor antigens are complex and heterogeneous, and identifying a single antigen that is uniformly expressed by tumor cells is challenging. Whole tumor cells can produce comprehensive antigens that trigger extensive tumor-specific immune responses. Therefore, tumor cells are an ideal source of antigens for tumor vaccines. A better understanding of tumor cell-derived vaccines and their characteristics, along with the development of new technologies for antigen delivery, can help improve vaccine design. In this review, we summarize the recent advances in tumor cell-derived vaccines in cancer immunotherapy and highlight the different types of engineered approaches, mechanisms, administration methods, and future perspectives. We discuss tumor cell-derived vaccines, including whole tumor cell components, extracellular vesicles, and cell membrane-encapsulated nanoparticles. Tumor cell-derived vaccines contain multiple tumor antigens and can induce extensive and potent tumor immune responses. However, they should be engineered to overcome limitations such as insufficient immunogenicity and weak targeting. The genetic and chemical engineering of tumor cell-derived vaccines can greatly enhance their targeting, intelligence, and functionality, thereby realizing stronger tumor immunotherapy effects. Further advances in materials science, biomedicine, and oncology can facilitate the clinical translation of tumor cell-derived vaccines.

Abstract OT1-19-01: A Single Arm Phase 2 Study of Peri-Operative Checkpoint-Mediated Immune Therapy and Cryoablation in Women with Hormone Receptor-Negative, HER2-Negative Early Stage/Resectable Breast Cancer

Abstract Background: Local tumor destruction with cryoablation (cryo) induces inflammation and releases antigens that can activate tumor-specific immune responses. Pre-clinically, cryo with immune checkpoint inhibition (ICI)-augmented tumor-specific immune responses and prevented recurrence. Clinically, we established that peri-operative (peri-op) cryo with ipilimumab (ipi) +/- nivolumab (nivo) was not only safe in patients (pts) with operable, early stage breast cancer (ESBC) but also generated robust intra-tumoral and systemic immune responses. In this phase 2 study, we evaluate the disease specific impact of peri-op ICI in women with residual triple negative breast cancer (TNBC) after neoadjuvant chemotherapy (NAC), a subset at high risk of early relapse. Methods: Eligible pts are ≥18y, with ER < 10%, PR < 10%, HER2 negative (per ASCO/CAP definition), ≥ 1.0 cm, residual operable disease after taxane-based NAC. Approximately 80 pts will be enrolled and treated with ipi/nivo/cryo followed by breast surgery and adjuvant nivo across multiple institutions. Pts undergo percutaneous, image-guided cryo with concurrent research core biopsy 7-10 days prior to surgery and will receive ipi (1mg/kg IV) with nivo (240mg IV) 1 to 5 days prior to cryo. After surgery, pts will receive 3 additional doses of nivo at 240mg IV Q2 weeks. Adjuvant capecitabine is recommended for all patients per local standard-of-care. Patients will be stratified by NAC platinum administration, NAC anthracycline administration, and clinical nodal status (positive versus negative). The primary endpoint is 3-year Event Free Survival (EFS). Secondary endpoints include Invasive Disease-Free Survival (IDFS), Distant Disease-Free Survival (DDFS), overall survival (OS) and safety. Exploratory correlative studies will be performed on tumor and serum to characterize the immunologic impact of the intervention and to explore predictors of efficacy and toxicity. Funding sources: Susan G. Komen, ASCO Conquer Cancer Foundation, Breast Cancer Research Foundation, Bristol-Myers Squibb, BTG International Ltd. NCT03546686 Citation Format: Heather McArthur, Elizabeth Comen, Yolanda Bryce, Stephen Solomon, Jorge Henrique Santos Leal, Christina DiLauro Abaya, Cristal Martinez, Reva Basho, Dorothy Park, Philomena McAndrew, Brigid Larkin, William Mills, David B. Page, Staci Mellinger, Nicole Fredrich, Nicole Moxon, Sangeetha Reddy, Meredith Carter, Sujata Patil, Larry Norton. A Single Arm Phase 2 Study of Peri-Operative Checkpoint-Mediated Immune Therapy and Cryoablation in Women with Hormone Receptor-Negative, HER2-Negative Early Stage/Resectable Breast Cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-19-01.

Targeting STING to promote antitumor immunity.

Pharmacology-based methods that promote antitumor immunity have the potential to be highly efficacious while avoiding the systemic cytotoxicity associated with traditional chemotherapies. Activation of type I interferon (IFN) signaling in antigen-presenting cell types [e.g., macrophages and dendritic cells (DCs)] is critical, if not essential, for inducing a tumor-specific adaptive immune response, including the activation of cytolytic CD8 T cells. In the context of promoting antitumor immunity, the cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) pathway has emerged as a principal regulator of essential type I IFN signaling. As such, STING represents a highly attractive target for developing a first-in-class immunotherapy, albeit one with a potential for significant cell type- and downstream pathway-dependent on-target toxicities, as well as conceivable pharmacogenomic liabilities.

Abstract PD2-04: Preclinical development of CodaLytic™, a codon-modified influenza virus, as a novel virotherapeutic agent for breast cancer immunotherapy

Abstract Multiple species of oncolytic viruses (OVs) have been shown to modulate the tumor microenvironment (TME) by increasing immune cell infiltration and activating stimulatory immune responses, leading to the induction of a tumor-specific immune response. Many engineered OVs achieve tumor specificity by either gene deletion or mutations and are then armed with immunomodulatory transgenes to promote anti-tumor immune responses. In an alternative approach, OVs derived from Codagenix’s codon/codon pair modification platform aim to leverage the natural immunostimulatory capacity of selected viral species for efficacy and take advantage of defects in innate immune sensing and apoptosis mechanisms in cancer cells as well as receptor overexpression for tumor selectivity. CodaLytic is a novel virotherapeutic derived from influenza virus strain A/California/07/2009, that is synthetically engineered to contain over 600 silent mutations in hemagglutinin and neuraminidase genes and is being developed as a novel immunotherapeutic for breast cancer. In the orthotopic EMT6 triple-negative breast cancer model, known for its moderate sensitivity to immunotherapies, intratumoral injection of 108 PFU three times a week for up to 4 weeks as a monotherapy led to significant tumor growth inhibition by 76% (p < 0.001 vs vehicle control), translating into a significant survival benefit with a 66% cure rate. Intravenous rechallenge of EMT6 long-term survivors led to a 27-fold reduction in lung nodule formation and a tumor-specific interferon-γ memory response was observed ex vivo in their splenocytes. Anti-tumor efficacy after CodaLytic treatment was accompanied by a change in the composition of the tumor immune infiltrate with significant increases in T, B and NK cells and increased gene expression of pathways and genes related to T cell effector function, dendritic cell activation, antigen presentation and chemoattraction. In immunotherapy-resistant orthotopic 4T1 tumors, combination of CodaLytic with a CTLA-4 inhibitory antibody, but not anti-PD-1 blockade – a combination that had demonstrated combination benefit in several other preclinical models – led to reduction in tumor growth by 75% (p < 0.0001 vs vehicle control and PD-1 combination group). Median overall survival improved from 22 to 30 days with addition of CTLA-4 blockade. Triple combination including PD-1 inhibition led to improved long-term survival beyond 50 days with 30% complete regressions. In summary, these preclinical data demonstrate CodaLytic’s ability to induce broad innate and adaptive changes in the breast cancer TME, resulting in anti-tumor efficacy and prolonged survival. Characterization of the tumor immune infiltrate after CTLA-4 combination and pharmacodynamic changes achieved after CodaLytic/checkpoint combination treatment in human breast cancer tumoroids will further support identification of correlates of efficacy with translational implications. Together with preclinical toxicology data and demonstrated clinical safety of this attenuated influenza virus after intranasal administration in healthy individuals, CodaLytic emerges as a promising novel viroimmunotherapeutic agent and is planned to enter a phase 1 clinical trial in early 2023. Citation Format: Marcin Stawowczyk, Yiwen Zhao, Katie Pfeffer, Juliana Tafrova, James Rodriguez, Chen Yang, Nusrat Jahan, Sybil A. Tasker, Steffen Mueller, J. Robert Coleman, Johanna K. Kaufmann. Preclinical development of CodaLytic™, a codon-modified influenza virus, as a novel virotherapeutic agent for breast cancer immunotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD2-04.

Altered HLA-A2-restricted TP53 epitope induces specific CTL cytotoxicity against hepatocellular carcinoma.

High-frequency mutation of the TP53 tumor suppressor gene is observed in multiple human cancers, which promotes cancer progression. However, the mutated gene-encoded protein may serve as a tumor antigen to elicit tumor-specific immune responses. In this study, we detected widespread expression of shared TP53-Y220C neoantigen in hepatocellular carcinoma with low affinity and low stability of binding to HLA-A0201 molecules. We substituted the amino acid sequences VVPCEPPEV with VLPCEPPEV in the TP53-Y220C neoantigen to yield a TP53-Y220C (L2) neoantigen. This altered neoantigen was found to increase affinity and stability and induce more cytotoxic T lymphocytes (CTLs), indicating improvements in immunogenicity. In vitro assays showed the cytotoxicity of CTLs stimulated by both TP53-Y220C and TP53-Y220C (L2) neoantigens against multiple HLA-A0201-positive cancer cells expressing TP53-Y220C neoantigens; however, the TP53-Y220C (L2) neoantigen showed higher cytotoxicity than the TP53-Y220C neoantigen against cancer cells. More importantly, in vivo assays demonstrated greater inhibition of hepatocellular carcinoma cell proliferation by TP53-Y220C (L2) neoantigen-specific CTLs relative to TP53-Y220C neoantigen in zebrafish and nonobese diabetic/severe combined immune deficiency mouse models. The results of this study demonstrate enhanced immunogenicity of the shared TP53-Y220C (L2) neoantigen, which has the potential as dendritic cells or peptide vaccines for multiple cancers.

Current Strategies for Modulating Tumor-Associated Macrophages with Biomaterials in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the fourth most common cause of cancer-related deaths in the world. However, there are currently few clinical diagnosis and treatment options available, and there is an urgent need for novel effective approaches. More research is being undertaken on immune-associated cells in the microenvironment because they play a critical role in the initiation and development of HCC. Macrophages are specialized phagocytes and antigen-presenting cells (APCs) that not only directly phagocytose and eliminate tumor cells, but also present tumor-specific antigens to T cells and initiate anticancer adaptive immunity. However, the more abundant M2-phenotype tumor-associated macrophages (TAMs) at tumor sites promote tumor evasion of immune surveillance, accelerate tumor progression, and suppress tumor-specific T-cell immune responses. Despite the great success in modulating macrophages, there are still many challenges and obstacles. Biomaterials not only target macrophages, but also modulate macrophages to enhance tumor treatment. This review systematically summarizes the regulation of tumor-associated macrophages by biomaterials, which has implications for the immunotherapy of HCC.

Orchestrated Cytosolic Delivery of Antigen and Adjuvant by Manganese Ion-Coordinated Nanovaccine for Enhanced Cancer Immunotherapy.

Cancer vaccines have received tremendous attention in cancer immunotherapy due to their capability to induce a tumor-specific immune response. However, their effectiveness is compromised by the insufficient spatiotemporal delivery of antigens and adjuvants in the subcellular level to induce a robust CD8+ T cell response. Herein, a cancer nanovaccine G5-pBA/OVA@Mn is prepared through multiple interactions of manganese ions (Mn2+), benzoic acid (BA)-modified fifth generation polyamidoamine (G5-PAMAM) dendrimer, and the model protein antigen ovalbumin (OVA). In the nanovaccine, Mn2+ not only exerts a structural function to assist OVA loading as well as its endosomal escape, but works as an adjuvant of stimulator of interferon genes (STING) pathway. These collaboratively facilitate the orchestrated codelivery of OVA antigen and Mn2+ into cell cytoplasm. Vaccination with G5-pBA/OVA@Mn not only shows a prophylactic effect, but also significantly inhibits growth against B16-OVA tumors, indicating its great potential for cancer immunotherapy.

Current Status and Challenges of Vaccination Therapy for Glioblastoma.

Glioblastoma (GBM), also known as grade IV astrocytoma, is the most common and deadly type of central nervous system malignancy in adults. Despite significant breakthroughs in current GBM treatments such as surgery, radiotherapy, and chemotherapy, the prognosis for late-stage glioblastoma remains bleak due to tumor recurrence following surgical resection. The poor prognosis highlights the evident and pressing need for more efficient and targeted treatment. Vaccination has successfully treated patients with advanced colorectal and lung cancer. Therefore, the potential value of using tumor vaccines in treating glioblastoma is increasingly discussed as a monotherapy or in combination with other cellular immunotherapies. Cancer vaccination includes both passive administration of monoclonal antibodies and active vaccination procedures to activate, boost, or bias antitumor immunity against cancer cells. This article focuses on active immunotherapy with peptide, genetic (DNA, mRNA), and cell-based vaccines in treating GBM and reviews the various treatment approaches currently being tested. Although the ease of synthesis, relative safety, and ability to elicit tumor-specific immune responses have made these vaccines an invaluable tool for cancer treatment, more extensive cohort studies and better guidelines are needed to improve the efficacy of these vaccines in anti-GBM therapy.

Surface Engineering of Lanthanide Nanoparticles for Oncotherapy.

Surface-modified lanthanide nanoparticles have been widely developed as an emerging class of therapeutics for cancer treatment because they exhibit several unique properties. First, lanthanide nanoparticles exhibit a variety of diagnostic capabilities suitable for various image-guided therapies. Second, a large number of therapeutic molecules can be accommodated on the surface of lanthanide nanoparticles, which can simultaneously achieve combined cancer therapy. Third, multivalent targeting ligands on lanthanide nanoparticles can be easily modified to achieve high affinity and specificity for target cells. Last but not least, lanthanide nanoparticles can be engineered for spatially and temporally controlled tumor therapy, which is critical for developing precise and personalized tumor therapy. Surface-modified lanthanide-doped nanoparticles are widely used in cancer phototherapy. This is due to their unique optical properties, including large anti-Stokes shifts, long-lasting luminescence, high photostability, and the capacity for near-infrared or X-ray excitation. Upon near-infrared irradiation, these nanoparticles can emit ultraviolet to visible light, which activates photosensitizers and photothermal agents to destroy tumor cells. Surface modification with special ligands that respond to tumor microenvironment changes, such as acidic pH, hypoxia, or redox reactions, can turn lanthanide nanoparticles into a smart nanoplatform for light-guided tumor chemotherapy and gene therapy. Surface-engineered lanthanide nanoparticles can include antigens that elicit tumor-specific immune responses, as well as immune activators that boost immunity, allowing distant and metastatic tumors to be eradicated. The design of ligands and surface chemistry is crucial for improving cancer therapy without causing side effects. In this Account, we classify surface-modified lanthanide nanoparticles for tumor therapy into four main domains: phototherapy, radiotherapy, chemotherapy, and biotherapy. We begin by introducing fundamental bioapplications and then discuss recent developments in tumor phototherapy (photodynamic therapy and photothermal therapy), radiotherapy, chemotherapy, and biotherapy (gene therapy and immunotherapy). We also assess the viability of a variety of strategies for eliminating tumor cells through innovative pathways. Finally, future opportunities and challenges for the development of more efficient lanthanide nanoprobes are discussed.

Bioactive Peptide Nanodrugs Based on Supramolecular Assembly for Boosting Immunogenic Cell Death-Induced Cancer Immunotherapy.

Immunogenic cell death (ICD)-induced immunotherapy holds promise for complete elimination and long-term protective immune responses against cancer by combining direct tumor cell killing and antitumor immune response. Some therapeutic approaches (such as hyperthermia, photodynamic therapy, or radiotherapy) and inducers (certain chemotherapy drugs, oncolytic viruses) have been devoted to initiating and/or boosting ICD, leading to the activation of tumor-specific immune responses. Recently, supramolecular assembled bioactive peptide nanodrugs have been employed to improve the efficacy of ICD-induced cancer immunotherapy by increasing tumor targeted accumulation as well as responsive release of ICD inducers, directly inducing high levels of ICD and realizing the simultaneous enhancement of immune response through the immune function of the active peptide itself. Here, the authors review bioactive peptide nanodrugs based on supramolecular assembly, mainly as an intelligent delivery system, a direct ICD inducer and an immune response enhancer, for boosting ICD induced cancer immunotherapy. The functions of diverse bioactive peptides used in the construction of nanodrugs are described. The design of a supramolecular assembly, the mechanism of boosting ICD, and synergetic effects of bioactive peptides combined immunotherapy are critically emphasized.