Systemic Antitumor Immune Response Research Articles

Engineering Bimetallic Polyphenol for Mild Photothermal Osteosarcoma Therapy and Immune Microenvironment Remodeling by Activating Pyroptosis and cGAS-STING Pathway.

The immunosuppressive tumor microenvironment (ITME) of osteosarcoma (OS) poses a significant obstacle to the efficacy of existing immunotherapies. Despite the attempt of novel immune strategies such as immune checkpoint inhibitors and tumor vaccines, their effectiveness remains suboptimal due to the inherent difficulty in mitigating ITME simultaneously from both the tumor and immune system. The promotion of anti-tumor immunity through the induction of immunogenic cell death and activation of the cGAS-STING pathway has emerged as potential strategies to counter the ITME and stimulate systemic antitumor immune responses. Here, a bimetallic polyphenol-based nanoplatform (Mn/Fe-Gallate nanoparticles coated with tumor cell membranes is presented, MFG@TCM) which combines with mild photothermal therapy (PTT) for reversing ITME via simultaneously inducing pyroptosis in OS cells and activating the cGAS-STING pathway in dendritic cells (DCs). The immunostimulatory pathways, through the syngeneic effect, exerted a substantial positive impact on promoting the secretion of damage-associated molecular patterns (DAMPs) and proinflammatory cytokines, which favors remodeling the immune microenvironment. Consequently, effector T cells led to a notable antitumor immune response, effectively inhibiting the growth of both primary and distant tumors. This study proposes a new method for treating OS using mild PTT and immune mudulation, showing promise in overcoming current treatment limitations.

Phosphatidylserine and Tyro3-Axl-Mertk Receptor Tyrosine Kinase level detection in plasma and on plasma-derived extracellular vesicle surface in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a chronic lymphoproliferative disorder characterized by monoclonal B cell proliferation. Studies carried out in recent years suggest that extracellular vesicles (EVs) may be a potential biomarker in cancer. Tyro3-Axl-Mertk (TAM) Receptor Tyrosine Kinases (RTKs) and Phosphatidylserine (PS) have crucial roles in macrophage-mediated immune response under normal conditions. In the tumor microenvironment, these molecules contribute to immunosuppressive signals and prevent the formation of local and systemic antitumor immune responses. Based on this, we aimed to evaluate the amount of PS and TAM RTK in plasma and on the surface of EVs in CLL patients and healthy volunteers in this study. In this study, 25 CLL (11 F/14 M) patients in the Rai (O-I) stage, newly diagnosed or followed up without treatment, and 15 healthy volunteers (11 F/4 M) as a control group were included. For all samples, PS and TAM RTK levels were examined first in the plasma and then in the EVs obtained from the plasma. We detected a significant decrease in plasma PS, and TAM RTK levels in CLL patients compared to the control. Besides, we determined a significant increase in TAM RTK levels on the EV surface in CLL, except for PS. In conclusion, these receptor levels measured by ELISA in plasma may not be effective for the preliminary detection of CLL. However, especially TAM RTKs on the surface of EVs may be good biomarkers and potential targets for CLL therapies.

Self-sacrificed construction of versatile nanoadjuvant for synergistically enhanced immunogenic cell death and improved anti-tumor immunity

Immune checkpoint blocking (ICB) antibodies have witnessed great success in the clinic, but a significant subset of patients suffers from limited responses to ICB therapies. Collaboration of ICB therapy with immunogenic cell death (ICD) are expected to potentiate systemic antitumor immune response for tumor inhibition and metastasis prevention. In this study, we develop a novel Cu-Mn bimetallic nanoadjuvant (CMI-PEG) consist of porous CuMnOx with IR820 cargo and surface PEGylation for immune therapy. Under NIR laser irradiation, this CMI-PEG nanoadjuvant can induce PTT/PDT/CDT synergistic therapy with improved oxygen generation and GSH consumption, eliciting efficient ICD of tumor cells. Synergized with ICB antibodies, promoted T lymphocytes infiltration and increased antitumor immune responses are evoked for efficient inhibition of distant and metastasis tumor growth, which is emphasized by admirable in vivo experimental results. Collectively, this study presents a novel self-sacrificing template strategy to synthesize hollow and porous CuMnOx nanomateial and the constructed CMI-PEG nanoadjuvant holds great promise in synergistic ICD activation and potentiation of ICB therapy.

Engineered delivery platform based on bacterial outer membrane vesicles for efficient labeling of 131I and improved radio-immunotherapy

Radioisotope therapy (RIT) is one of clinical treatment for tumors, which can not only directly kill tumor cells, but also enhance anti-tumor immune response by inducing tumor cell immunogenic cell death (ICD). However, significant challenges for RIT are the low radiolabeling efficiency, as well as tumor targeting issues. Bacterial outer membrane vesicles (OMVs), which are natural nano-vesicles secreted by Gram-negative bacteria, are now garnering significant attention in cancer therapy due to their tumor-targeting and immunotherapeutic potential. Herein, we construct an engineering delivery platform based on OMVs to achieve efficient labeling of radioactive iodine and improve radio-immunotherapy (131I-STATH-OMV-PEG). Firstly, high tyrosine-rich protein statherin (STATH) is integrated onto the surface of OMVs (STATH-OMV) through bioengineered technology. The obtained STATH-OMV is coated with polyethylene glycol (PEG) and then labeled with radionuclide iodine-131 (131I-STATH-OMV-PEG), which exhibit excellent radiolabeling efficiency due to the integration of STATH. More importantly, 131I-STATH-OMV-PEG could also boost DC maturation and produce anti-tumor cytokines, thereby enhancing the systemic anti-tumor immune response induced by RIT. Additionally, 131I-STATH-OMV-PEG could inhibit orthotopic colon cancer, induce systemic immune memory effect and prevent tumor invasion. In summary, this study proposes an OMV-centered RIT delivery system that ensures proficient labeling of 131I, thereby amplifying the therapeutic effect of RIT and opening up a promising approach for tumor radio-immunotherapy.

Augmented antitumor immune responses of HER2-targeted pyroptotic induction by long-lasting recombinant immunopyroptotins

Pyroptosis is a well-documented form of programmed cell death caused by the gasdermin-driven perforation of cell membranes. Selective induction of pyroptosis in tumor cells represents a promising antitumor strategy to enhance the efficacy of immunotherapy. In this study, we established a recombinant protein-based immunopyroptotin strategy that led to the intratumoral induction of pyroptosis for HER2-directed therapy. Long-lasting immunopyroptotins were constructed by sequentially fusing the humanized anti-HER2 single-chain antibody P1h3, albumin-binding peptide (ABD035 or dAb7h8), cathepsin B-cleavable peptide B2, endosome-disruptive peptide E5C3, and active pyroptotic effector gasdermin D-N fragment (GN). After purification, we evaluated the cytotoxicity and antitumor immune responses primarily induced by the immunopyroptotins in HER2-overexpressing breast cancer cells. The resulting ABD035-immunoGN and dAb7h8-immunoGN showed improved in vitro cytotoxicity in HER2-overexpressing cancer cells compared with that in the immunotBid that we previously generated to induce tumor cell apoptosis. The binding of long-lasting immunopyroptotins to albumin increased the half-life by approximately 7-fold in nude mice. The enhanced antitumor efficacy of long-lasting immunopyroptotins was confirmed in both N87 tumor-bearing T cell-deficient mice and 4T1-hHER2 bilateral tumor-bearing immunocompetent mice. Immunopyroptotin treatment elicited systemic antitumor immune responses involving CD8+ T cells and mature dendritic cells and upregulated the expression of proinflammatory cytokines, leading to sustained remission of non-injected distant tumors. This study extends the repertoire of antibody-based therapeutics through the tumor-targeted delivery of a constitutively active pore-forming gasdermin-N fragment, which shows great potential for pyroptosis-based antitumor therapy.

Abstract 7260: An HSV-1-based vector for local delivery of IL-12 and IL-2 reshapes the immune landscape leading to tumor clearance and systemic immune surveillance

Abstract Clinical use of recombinant interleukin (IL)-12 and -2 therapy has been hindered due to unfavorable kinetics and toxicity associated with systemic exposure. Durable targeted delivery to the tumor microenvironment (TME) is a promising therapeutic strategy to overcome these clinical limitations, prompting the development of KB707, a replication-defective herpes simplex virus type 1 (HSV-1)-based vector encoding human IL-12 and -2, for the treatment of solid tumors. Prior studies in mice demonstrated that local vector-encoded cytokine administration enhanced murine IL-12/IL-2 expression while limiting systemic exposure compared to conventional protein therapy. In a syngeneic, B16-F10 melanoma mouse model, intratumoral murine KB707-equivalent treatment led to improved survival in a unilateral tumor model and an abscopal effect in a bilateral tumor model. Additionally, the majority of previously treated animals survived rechallenge with B16-F10 in the absence of further therapy, indicative of systemic anti-tumor immune memory. Together, these results suggested that vector-mediated delivery of IL-12 and -2 could elicit both local and systemic anti-tumor immune responses. To elucidate the underlying changes to the immune landscape, B16-F10 tumor-bearing animals were treated intratumorally with vector or vehicle control on day 0 and were sacrificed on day 7; a second cohort of tumor-bearing animals received two vector doses (days 0 and 7) and were sacrificed on days 8, 10, 12, or 14. Immune cell profiling of samples taken from the tumor, tumor draining lymph node (dLN), spleen, and whole blood were analyzed by flow cytometry, and serum cytokine analysis was conducted by multiplex ELISA. Flow cytometric analysis of tumors revealed that vector treatment resulted in increased frequencies of proliferating and activated effector CD8+ and CD4+ T cells, peaking 24 hours post-second dose. These results correlated with high levels of the proinflammatory cytokines IFNγ and TNFα in the serum of vector recipient animals. The blood, spleens, and dLNs also showed increased frequencies of activated effector CD8+ and CD4+ T cells, peaking 24-72 hours post-second dose. Interestingly, although IL-2 alone has been shown to promote immune suppression and tumor outgrowth by mediating regulatory T cell (Treg) expansion and infiltration in certain contexts, the frequency of Tregs in treated vs. control tumors was substantially reduced after first and repeat dosing. Together, these results support a mechanism by which vector-driven local expression of IL-12 and IL-2 can expand and activate effector T cells both in the TME and systemically while simultaneously repressing Tregs, consistent with the previously described inhibition of primary tumor outgrowth, abscopal effects on secondary tumors, and prevention of recurrence observed with this therapeutic approach. Citation Format: Dana M. Previte, Trevor J. Parry, Suma M. Krishnan. An HSV-1-based vector for local delivery of IL-12 and IL-2 reshapes the immune landscape leading to tumor clearance and systemic immune surveillance [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 7260.

Abstract 3186: An Erythrocyte-αPD-1 conjugate suppresses cancers resistant to checkpoint blockade immunotherapy: A first-in-human study

Abstract Background: Immune checkpoint blockade (ICB) therapy has revolutionized cancer treatment, yet resistance to this therapy can lead to immune escape and disease progression. Here, we introduce WTX-212, an erythrocyte-antibody conjugate covalently linking anti-PD-1 antibody to erythrocyte membranes. Unlike conventional antibodies, WTX-212 naturally accumulates in the spleen and remodels the splenic immune landscape in tumor-bearing mice. Pre-clinical studies have demonstrated that T cells activated by WTX-212 reduce the splenic reservoir of immunosuppressive myeloid cells, including those within tumors. This results in a systemic anti-tumor immune response and suppression of tumor growth in xenograft tumor models resistant to anti-PD-1 immunotherapies. A first-in-human (FIH) clinical trial is now investigating its potential in human cancer patients. Methods: The FIH trial (NCT05707325) is aimed to investigate the safety, pharmacokinetics, mechanisms and preliminary efficacy of WTX-212 in cancer patients with advanced malignancies. All of patients had previously received anti-PDs therapies and developed resistance to these treatments. By November 15th, 2023, 7 patients across two cohorts had received WTX-212 monotherapy (1 × 1011-2 × 1011 cells, Q3W IV). The tumor lesions were assessed using RECIST v1.1 criteria. Blood and tumor samples were collected for correlative analysis. Results: 7 patients with various solid tumors, having undergone a median of 3.1 prior lines of therapy (ranging from 1-6), received WTX-212 monotherapy. No dose-limiting toxicities or treatment-related adverse events greater than Grade 3 were reported. WTX-212 was detectable in peripheral blood at the end of cycle in a dose dependent manner. Disease control, including partial remission (PR) and stable disease (SD), was observed in 5/7 patients (DCR, 71%). One patient with esophageal cancer achieved a PR with a significant 44% reduction in target lesion size after two cycles of treatment. Two patients, one with esophageal cancer (3 lines prior therapies) and another with HPV-negative cervical cancer (4 lines prior therapies), maintained disease control for over 30 weeks after WTX-212 treatment. Consistent with preclinical findings, WTX-212 systemically induced anti-tumor responses, leading to a reduction of myeloid-derived suppressor cells (MDSCs) particularly the PMN-MDSC subset in 6/7 patients (reductions ranging from 24%-82% compared to baseline), and a median 1.5-fold increase of T cells in 7/7 patients in the peripheral blood after the 1st cycle of treatment. Conclusion: The initial promising data support further investigation and exploration of the combination therapy strategies to expand the therapeutic potential of WTX-212 in cancer patients. Erythrocyte-drug conjugation may serve as a unique strategy for targeting the peripheral immune system to treat cancers. Citation Format: Liu Yang, Xiaoqian Nie, Zheling Chen, Yuehua Liu, Jiawei Zheng, Xiaofei Gao. An Erythrocyte-αPD-1 conjugate suppresses cancers resistant to checkpoint blockade immunotherapy: A first-in-human study [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 3186.

Abstract 5761: A nanoplatform based on an in situ tumor vaccine and activation of STING and TLR7/8 pathways for enhanced NSCLC immunotherapy

Abstract Background: Immunotherapy has emerged as a promising treatment for tumors following surgical, radiotherapy, and chemotherapy interventions. Therapeutic tumor vaccines are considered highly effective in eliminating tumors and preventing their recurrence and metastasis due to their ability to induce or enhance T cell-mediated immune responses. However, the therapeutic efficacy of these vaccines is impeded by the heterogeneity present both between and within tumors. In contrast, in situ tumor vaccines, prepared from autologous antigens in tumor patients, present another promising strategy for generating comprehensive immune responses. Methods: In this study, we designed a multifunctional nanopolymer, the transformable nanoassembly PEG-Ce6@PAEMA/R848. This assembly includes the photosensitizer polyethylene glycol-chlorin-e6 (PEG-Ce6), the tumor pH-sensitive polymer poly(2-azepane ethyl methacrylate) (PAEMA), and the immune adjuvant Resiquimod (R-848). The objective is to confirm the activation of bone marrow-derived dendritic cells (DCs) at the cellular level. Subsequently, we investigated the maturation of DCs in lymph nodes and tumor sites in vivo. Results: In the particle characterization process, successful synthesis of nanoparticles was achieved, along with the verification of their acid-responsive function and toxic effects. Furthermore, in vitro experiments demonstrated the activation of bone marrow-derived dendritic cells (DCs) (Figure 1).To further investigate the in vivo vaccine effects, C57BL/6 mice were euthanized, and lymph nodes were extracted to examine the accumulation of FITC-PAEMA. It can be observed that, due to the reduction in size of the particles in the tumor acidic environment, the immune adjuvant can easily enter the lymph nodes. Activation of the STING pathway in dendritic cells within the lymph nodes was detected through qPCR. The maturation of dendritic cells (DCs) in the lymph nodes was determined using flow cytometry (Figure 2). Conclusions: In this study, we developed a straightforward yet potent strategy focused on in situ tumor targeting. This approach effectively inhibits tumor growth while inducing immunogenic cell death and eliciting a systemic anti-tumor immune response against cancer cells. Additionally, we intend to validate the therapeutic efficacy of this strategy on metastatic and distal tumors in subsequent investigations. Citation Format: Haiyu Zhou, Hengliang Hou, Bin Xu, Yucheng Huang, Hongrui Qiu. A nanoplatform based on an in situ tumor vaccine and activation of STING and TLR7/8 pathways for enhanced NSCLC 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 5761.

Abstract 4995: Impact of radiotherapy on extracellular vesicle mediated anti-tumor immunity in oligometastatic prostate cancer

Abstract Metastasis-ablative radiotherapy is a new therapeutic approach that prolongs survival in patients with advanced cancers. Tumour irradiation can elicit an immunogenic cell death resulting in the expansion of tumour-reactive T cells and eradication of both irradiated and distant non-irradiated metastases, referred to as the “abscopal effect”. This abscopal response, nevertheless, is observed in a minority of patients suggesting uncharacterized mechanisms that prevent robust systemic anti-tumor immune response. Tumour-derived extracellular vesicles (TdEVs) have recently emerged as mediators of antitumor immunity but their immunomodulatory role in response to radiotherapy remains largely unknown. Recent clinical studies by our lab have demonstrated that circulating levels of tumour-derived extracellular vesicles (tdEVs) are elevated in response to radiotherapy and high tdEV concentrations are associated with reduced levels of peripheral cytotoxic CD8+ T cells and higher risk of disease recurrence in advanced prostate cancer. Based on our findings, we hypothesize that radiotherapy induces the release of tumor-derived EVs that suppress anti-tumor immunity. Prostate cancer cells (PC3 and DU145) were irradiated with clinically used doses of ionizing radiation (20Gy x 1 or 10Gy x 3 fractions) and tdEVs were co-cultured with human CD8+ T cells to measure their proliferation and cytotoxic activity. Increased levels of tdEVs were released by tumour cells treated with radiotherapy. A higher frequency of impaired T cell cytotoxic activity and a reduction in CD8 T cell proliferation was found in the 10Gy x 3 radiation regimen. Proteomic analysis and western blot showed an increased expression of the immune checkpoint molecule B7-H3 on the tumour cell surface and tdEVs in response to radiotherapy. While coculture of CD8 T cells with B7-H3 depleted tdEVs led to recovery of T-cell cytotoxic ability, overexpression of the B7-H3 in tdEVs inhibited cytotoxic activity. This study provides a rationale for future studies in which we will test the immune-mediated effects of radiotherapy-induced tdEVs in immunocompetent mouse models and investigate B7-H3 blockade as a therapeutic approach to boost abscopal response in the treatment of advanced prostate cancer. Citation Format: Chisom J. Uzendu, Yohan Kim, Roxane R. Lavoie, Haidong Dong, Sean Park, Fabrice Lucien-Matteoni. Impact of radiotherapy on extracellular vesicle mediated anti-tumor immunity in oligometastatic prostate 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 4995.

Abstract 4058: Nanoparticle delivery of interleukin-2 induces anti-tumor immune response and therapeutic efficacy in mouse tumor models

Abstract Immune checkpoint inhibitors (ICIs) have demonstrated robust responses in some solid tumor types. However, the low response rate, which is associated with lack of pre-existing tumor-infiltrating lymphocytes (TILs), remains a significant challenge. Interleukin-2 (IL-2) can effectively expand TILs and has been FDA-approved for metastatic renal cancer and melanoma. However, IL-2 has several drawbacks—including short circulation half-life, dose-limiting toxicities, and counterproductive activation of regulatory T cells (Tregs)—resulting in less than 10% complete response rate. Numerous efforts have been made to enhance IL-2 formulations, but none have yet received FDA approval. In this study, we utilized our proprietary nanoparticle platform (Pdx-NP™) to improve IL-2 formulation. Pdx-NP™ can load IL-2 with near-complete binding, resulting in a 160-nm nanoconstruct (IL2-NP), suitable for both local and intravenous administrations. To evaluate the efficacy, we utilized bilateral melanoma (B16F10) and colon (MC38) tumor models, in which the local tumor was treated intratumorally for 3 doses and the distal tumor was left untreated to assess the systemic anti-tumor immune response. In the B16F10 model, IL2-NP treatment demonstrated favorable immune profiles in local and distal tumors and the draining lymph nodes, such as increased CD8+ T cell proliferation, CD8+ T cells/Treg ratio, and recruitment of dendritic cells and macrophages, compared to saline or free IL-2 counterparts. These positive immune responses translated into significant growth reduction of IL2-NP treated tumors and improvement in survival of the mice compared to free IL-2. In the MC38 tumor model, the IL2-NP treatment resulted in complete regression of both local and distal tumors in 43% of the mice. When combined with ICIs (αPD-1 and αCTLA-4), the treatment achieved a cure rate of 100%, whereas ICIs alone yielded only a 29% cure rate. In conclusion, IL2-NP induces robust proliferation and activation of TILs and is efficacious both as a monotherapy and in combination with ICIs. This is due to the ability of Pdx-NP™ to protect and retain therapeutics within tumors, with an 8-fold increase in tumor accumulation over the free drug counterpart. Our ongoing efforts are focused on the targeted delivery of IL-2 to tumors upon systemic administration, using αPD-L1 antibody-conjugated Pdx-NP™. This antibody-conjugated nanoparticle has an elimination half-life (t1/2) of about 25 hrs in non-human primates. Paired with αPD-L1 for tumor homing, this nanoconstruct is hypothesized to enhance IL-2 accumulation in tumors compared to free IL-2, which has t1/2 of only 1.5 hrs in human. The current clinical landscape of cancer immunotherapy focuses on combinational approaches, and our versatile Pdx-NP™ platform, which is capable of co-delivering different classes of therapeutics, is well suited for this endeavor. Citation Format: Ruijie Wang, Alyssa Wallstrum, Natalie White, Pramod Kumar, Tongchatra Watcharawittayakul, Noah A. Crumrine, Cole Baker, Jeremy Saito, Moataz Reda, Worapol Ngamcherdtrakul, Wassana Yantasee. Nanoparticle delivery of interleukin-2 induces anti-tumor immune response and therapeutic efficacy in mouse tumor models [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 4058.

The role of spleen radiomics model for predicting prognosis in esophageal squamous cell carcinoma patients receiving definitive radiotherapy.

The spleen plays an important role in systemic antitumor immune response, but whether spleen imaging features have predictive effect for prognosis and immune status was unknown. The aim of this study was to investigate computed tomography (CT)-based spleen radiomics to predict the prognosis of patients with esophageal squamous cell carcinoma (ESCC) underwent definitive radiotherapy (dRT) and to try to find its association with systemic immunity. This retrospective study included 201 ESCC patients who received dRT. Patients were randomly divided into training (n = 142) and validation (n = 59) groups. The pre- and delta-radiomic features were extracted from enhanced CT images. LASSO-Cox regression was used to select the radiomics signatures most associated with progression-free survival (PFS) and overall survival (OS). Independent prognostic factors were identified by univariate and multivariate Cox analyses. The ROC curve and C-index were used to evaluate the predictive performance. Finally, the correlation between spleen radiomics and immune-related hematological parameters was analyzed by spearman correlation analysis. Independent prognostic factors involved TNM stage, treatment regimen, tumor location, pre- or delta-Rad-score. The AUC of the delta-radiomics combined model was better than other models in the training and validation groups in predicting PFS (0.829 and 0.875, respectively) and OS (0.857 and 0.835, respectively). Furthermore, some spleen delta-radiomic features are significantly correlated with delta-ALC (absolute lymphocyte count) and delta-NLR (neutrophil-to-lymphocyte ratio). Spleen radiomics is expected to be a useful noninvasive tool for predicting the prognosis and evaluating systemic immune status for ESCC patients underwent dRT.

Oncolytic varicella-zoster virus engineered with ORF8 deletion and armed with drug-controllable interleukin-12

BackgroundThe varicella-zoster virus (VZV), belonging to the group of human α-herpesviruses, has yet to be developed as a platform for oncolytic virotherapy, despite indications from clinical case reports suggesting a...

Black phosphorus-based nanoparticles induce liver cancer cell mitochondrial apoptosis and immune cell tumor infiltration for enhancing dendritic cell therapy

Cellular immunotherapy is a crucial aspect of current tumor immunotherapy, though it presents several challenges such as immune cell dysfunction, limited recognition of neoantigens, and inadequate lymphocyte infiltration into the tumor microenvironment. This study proposes a novel approach utilizing a combination of dendritic cell (DC)-based cellular immunotherapy and a photothermal nanoadjuvant black phosphorus (BP) nanoparticles to overcome these challenges. A new platform called PLGA@BP-R848, which consists of modifying poly-(lactic-co-glycolic acid) (PLGA) onto BP nanosheets loading the immune adjuvant R848. The PLGA@BP-R848 nanoparticles demonstrated exceptional drug delivery and release capabilities, as well as a photothermal effect, biocompatibility, and the ability to activate the mitochondrial apoptotic pathway Blc-2-Bax-Cytochrome c-caspase-3 and inhibit the PI3K-AKT-mTOR signaling pathway. In a hepatocellular carcinoma mouse model, the binding of PLGA@BP-R848 nanoparticles and dendritic cells primed with GPC3 peptides, successfully induced a systemic anti-tumor immune response. PLGA@BP-R848 nanoparticles bolster immune cell infiltration into tumors and induce cancer cell apoptosis. The synergistic therapy involving dendritic cells and photothermal nanoadjuvant effectively suppressed tumor growth, and facilitated the formation of tertiary lymphatic structures (TLS) in tumors. This study presents a novel approach in using photothermal nanoadjuvants to advance antitumor effect of cellular immunotherapy, such as DCs therapy.

PIVOT-006: A phase 3, randomized study of cretostimogene grenadenorepvec versus observation for the treatment of intermediate risk non-muscle invasive bladder cancer (IR-NMIBC) following transurethral resection of bladder tumor (TURBT).

TPS715 Background: Guidelines for Intermediate Risk Non-Muscle Invasive Bladder Cancer (IR-NMIBC) recommend adjuvant intravesical (IVE) therapy or surveillance. Despite this, 30–60% of patients still recur, and these Guideline recommendations are lacking level-1 evidence. Thus, there is a considerable gap in knowledge and an unmet medical need for improved therapies in the adjuvant setting. Cretostimogene Grenadenorepvec is an oncolytic adenovirus designed to preferentially replicate in and kill cancer cells. The vector is transcriptionally regulated by the E2F promoter that is up-regulated in retinoblastoma (Rb) pathway-defective tumor cells, common in most IR-NMIBC bladder tumors. Additionally, the virus is engineered to selectively express GM-CSF, in order to induce a robust systemic anti-tumor immune response. PIVOT-006 is an open-label, multi-center, randomized Phase 3 study designed to assess the efficacy and safety of intravesical Cretostimogene after TURBT versus TURBT alone. Methods: Eligibility criteria: age ≥18 years, Eastern Cooperative Oncology Group performance status of 0-2, histologically confirmed IR-NMIBC with absence of nodal or metastatic disease at screening. IR-NMIBC, as defined by American Urologic Association-Society of Urologic Oncology Guidelines on NMIBC, is either a Low Grade (LG) stage Ta tumor that recurs within 12 months of prior LG or High Grade (HG) bladder cancer, a solitary LGTa tumor >3cm in size, multifocal LGTa tumors, primary HGTa lesion < 3cm in size, or a LGT1 tumor. Participants will be stratified by receipt of perioperative chemotherapy and tumor grade. Pts (N~450) will be randomized 1:1 to receive intravesical Cretostimogene (Cohort 1) adjuvant to TURBT or TURBT alone (Cohort 2). Single dose perioperative intravesical chemotherapy at the time of TURBT is permitted. If intravesical NMIBC recurrence is noted in Cohort 2, participants will be eligible to receive intravesical Cretostimogene. In Cohort 1, intravesical Cretostimogene will be instilled in combination with n-dodecyl-B-D-maltoside (DDM, an inactive detergent) for 6 weekly doses during the induction phase, followed by 3 weekly maintenance cycles at months 3 and 6, and culminating in single intravesical doses at months 9 and 12. Primary disease assessments include serial cystoscopy, urine cytology, axial imaging, and centralized review of pathologic samples. The primary outcome measure is recurrence free survival. Secondary outcome measures include safety, tolerability, progression free survival, and time to next intervention. Exploratory outcome measures include patient-reported quality of life, biomarker analyses, coxsackie adenovirus receptor and E2F promoter expression, neutralizing antibodies, and markers of immunogenicity. Clinical trial information: Pending.

In Vitro Sensitivity of Neuroendocrine Neoplasms to an Armed Oncolytic Measles Vaccine Virus

Neuroendocrine neoplasms represent a heterogenous group of rare tumors whose current therapeutic options show only limited efficacy. Oncolytic viruses exert their mode of action through (onco-)lysis of infected tumor cells and the induction of a systemic antitumoral immune response in a virus-induced inflammatory micromilieu. Here, we investigated the potential of our well-established second-generation suicide-gene armed oncolytic measles vaccine virus (MeV-SCD) in five human NEN cell lines. First, (i) expression of the MeV receptor CD46 and (ii) its correlation with primary infection rates were analyzed. Next, (iii) promising combination partners for MeV-SCD were tested by employing either the prodrug 5-fluorocytosine, which is converted into the chemotherapeutic compound 5-fluorouracil, or the mTOR-inhibitor everolimus. As a result, MeV-SCD was found to kill all NEN tumor cell lines efficiently in a dose-dependent manner. This oncolytic effect was further enhanced by exploiting the prodrug-converting system, which was found to be highly instrumental in overcoming the partial resistance found in a single NEN cell line. Furthermore, viral replication was unaffected by everolimus, which is a basic requirement for combined use in NEN patients. These data suggest that MeV-SCD has profound potential for patients with NEN, thus paving the way for early clinical trials.

H2S‐Mediated Gas Therapy and HSP90 Downregulation Synergically Enhance Tumor Microwave Thermal Therapy

AbstractMicrowave thermal therapy (MWTT) is a novel clinical treatment of tumors via inducing thermal effect and anti‐tumor immune response, exhibiting advantages of deep penetration, minimal invasion, and high heat conversion efficiency. However, effective ablation is difficult to cover the entire tumor area, and heat‐shock protein 90 (HSP90) is often upregulated after ablation to generate heat tolerance of sublethal tumors and weaken the induced antitumor immune effect, resulting in a high rate of tumor recurrence and metastasis. Herein, a multifunctional nanoregulator of metal phenolic network‐coated ZnS (ZnS@Ga‐tannic acid, ZGT) is proposed to release H2S for synergically enhancing MWTT. Under the costimulation of MW radiation and acidic tumor microenvironment, ZGT can improve the MW thermal effects of tumors to promote thermal damage and release H2S to induce tumor apoptosis. The released H2S can also inhibit the production of ATP and then downregulate the expression of HSP90, strengthening the activated systemic antitumor immune response after ablation. This nanoregulator provides a new way for achieving compensation effect for MWTT. The strategy of H2S gas to downregulate HSP90 and positively regulate antitumor immune response introduces a novel direction for reducing the risk of tumor recurrence and metastasis after thermal therapy.

A natural product-derived nanozyme regulator induced chemo-ferroptosis dual therapy in remodeling of the tumor immune microenvironment of hepatocellular carcinoma

Ferroptosis, an emerging cell death mode discovered in recent decades, is characterized by lipid peroxidation during cell death, usually manifested as iron accumulation. However, the forthright delivery of iron species will cause adverse detrimental effects such as anaphylactic reactions in routine tissues. So far, studies on cellular ferroptosis by employing bio-derived nanomaterials have rarely been acquired. Herein, we reported carbon dots (CDs)-based biocompatible enzymes with negligible toxicity from a representative hepatoprotective triterpenoid natural product ursolic acid (UA) with acknowledged antitumor activity. We observed that CDs presented distinct GSH oxidase-like characteristics and then contributed ferroptosis of carcinoma cells by interfering with the GPX4-catalyzed lipid repair system. After the CDs were assembled with UA, the obtained denoted as UCDs integrated multi-model therapy into one, resulting in enhanced therapeutic efficacy, reduced adverse effects, and optimized clinical outcomes. In vivo, the UCDs hysterically inhibited tumor growth in hepatoma H22-bearing mice with inconsequential toxicity. Exceptionally, UCDs enlisted a large number of tumor-infiltrating immune cells, including T cells, NK cells, and macrophages in H22 tumor-bearing mice, consequently transforming “cold” into “hot” tumors to activate systemic anti-tumor immune responses. Meanwhile, UCDs could also awfully suppress the H22-LUC tumor growth in orthotopic xenograft mouse models. Collectively, our research commends that the drug delivery systems based on natural-products-derived CDs can function as biocompatible enzymes for antitumor treatment and may facilitate the advancement of nanotechnology-based immunotherapeutics. It is extremely anticipated that such ferroptosis-like designing in nano-catalytic medicine would be favorable for future development in cancer-therapeutic regimens.

Enhanced Photodynamic Therapy Synergizing with Inhibition of Tumor Neutrophil Ferroptosis Boosts Anti-PD-1 Therapy of Gastric Cancer.

For tumor treatment, the ultimate goal in tumor therapy is to eliminate the primary tumor, manage potential metastases, and trigger an antitumor immune response, resulting in the complete clearance of all malignant cells. Tumor microenvironment (TME) refers to the local biological environment of solid tumors and has increasingly become an attractive target for cancer therapy. Neutrophils within TME of gastric cancer (GC) spontaneously undergo ferroptosis, and this process releases oxidized lipids that limit T cell activity. Enhanced photodynamic therapy (PDT) mediated by di-iodinated IR780 (Icy7) significantly increases the production of reactive oxygen species (ROS). Meanwhile, neutrophil ferroptosis can be triggered by increased ROS generation in the TME. In this study, a liposome encapsulating both ferroptosis inhibitor Liproxstatin-1 and modified photosensitizer Icy7, denoted LLI, significantly inhibits tumor growth of GC. LLI internalizes into MFC cells to generate ROS causing immunogenic cell death (ICD). Simultaneously, liposome-deliver Liproxstatin-1 effectively inhibits the ferroptosis of tumor neutrophils. LLI-based immunogenic PDT and neutrophil-targeting immunotherapy synergistically boost the anti-PD-1 treatment to elicit potent TME and systemic antitumor immune response with abscopal effects. In conclusion, LLI holds great potential for GC immunotherapy.

Macrophage-derived biomimetic nanoparticles enhanced SDT combined with immunotherapy inhibited tumor growth and metastasis

Combination therapy based on sonodynamic therapy (SDT) combined with immune checkpoint blockers anti-PD-L1 provides effective anti-tumor effects. We designed a combination therapy based on M1/PLGA@IR780/CAT NPs of SDT-enhanced immunity combined with immune checkpoint blockers against PD-L1, which was based on M1 macrophage membrane-encapsulated poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with the acoustic sensitizer IR780 and catalase (CAT) to successfully realize it. SDT based on M1/PLGA@IR780/CAT NPs could induce tumor cell death by promoting dendritic cell (DC) maturation and modulating the tumor immune microenvironment. In particular, the systemic anti-tumor immune response and potent immune memory induced upon combination with anti-PD-L1 checkpoint blockade not only alleviated the progression of mammary cancer in 4T1 mice and effectively blocked distant metastasis, but also prevented tumor recurrence, providing a promising new therapeutic strategy for clinical tumor 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.