Stimulation Of Antitumor Immune Response Research Articles

Effects of exosomes and inflammatory response on tumor: a bibliometrics study and visualization analysis via CiteSpace and VOSviewer

BackgroundTumor is a new organism formed by abnormal hyperplasia of local tissue cells under the action of various tumorigenic factors. Inflammation plays a decisive role in inducing tumorigenesis, promoting tumor development, invasion and migration. More and more evidence indicate that exosomes are involved in regulating the formation of tumor microenvironment in the process of proinflammatory carcinogenesis, leading to the stimulation of anti-tumor immune response or systemic immunosuppression, and exosomes play a crucial role in the development of tumor.MethodsThe articles on tumor-derived exosomes and inflammatory responses from January 2005 to January 2024 were collected through Web of Science (WOS), and the inclusion criteria were “Article”, “Review Article” and “Early Access”. Articles obtained after excluding “Book Chapters”, “Editorial Material”, “Proceeding Paper”, “Meeting ” and “Retracted Publication”. Bibliometrics and visualization analysis were carried out on the obtained articles using CiteSpace6.2.R6 and VOSviewer1.6.20.ResultsTotal of 703 articles were included. The number of published documents showed a fluctuating growth trend year by year. A total of 61 countries have participated in the research on the effects of exosomes and inflammatory responses on tumors, among which China and the United States have the largest influence in this field. The obtained articles have been published in 60 journals around the world, among which PLOS ONE and NAT REV IMMUNOL are the journals with the most published articles and the highest co-citations respectively. The article from French author THERY C was cited the most (202 times). As a major researcher on the basic function of exosomes, THERY C established the gold standard for extraction, separation and identification of exosomes, and found that exosomes promote tumor metastasis through direct regulation of miRNA. Her research has had a huge impact on the field. Keyword co-occurrence analysis indicate that extracellular vesicles, inflammation, cancer, miRNAs, mesenchymal stem cells, drug delivery, gastric cancer and circulating endothelial microparticles are the research hotspot at present stage. The main keywords of the cluster analysis show that extracellular vesicles, human papilloma virus, myeloid cells, tumor macro-environment are the current research hotspots and frontier. The research hotspots have developed over time from the time chart of keywords and clustering, especially after 2016, exosomes have established extensive links with drug delivery, cancer treatment, inflammatory response and other fields. Tumor-derived exosomes stimulate receptor cells to secrete pro-inflammatory cytokines and growth factors, enabling immune and inflammatory cells to perceive the intracellular environment of cancer cells even when cancer cells do not express any tumor-specific antigens. For example, in anoxic environment, cancer cells can secrete exosomes containing pro-inflammatory factors to promote the invasion and metastasis of cancer cells. In the complex tumor microenvironment, both tumor cells and various stromal cells will secrete specific exosomes, and promote the development of tumors through various ways, so that tumor cells have drug resistance, and bring adverse effects on the clinical treatment of tumor patients. MicroRNAs and long noncoding RNA as hot keywords play important roles in regulating and mediating tumor development, and their specificity makes them important biomarkers for cancer prediction and diagnosis. Highlighting word analysis shows that microRNAs secreted by leukemia patients can effectively promote the proliferation of malignant cells and the development of cardiovascular diseases. At the same time, exosomes can induce the secretion of some microRNAs in patients, leading to cardiac repair and regeneration. Therefore, the detection and screening of microRNAs plays a crucial role in predicting the incidence of cardiovascular diseases in patients.ConclusionExosomes have attracted increasing attention due to their significant heterogeneity and ability to regulate the tumor immune microenvironment. However, tumor cell-derived exosomes accelerate tumor progression by enhancing immunosuppression and inflammation, increasing oxidative stress, and promoting angiogenesis, which may lead to poor prognosis.Graphical abstract

Revitalizing Bacillus Calmette-Guérin Immunotherapy for Bladder Cancer: Nanotechnology and Bioengineering Approaches.

Bacillus Calmette-Guérin (BCG) immunotherapy has been a cornerstone treatment for non-muscle-invasive bladder cancer for decades and still faces challenges, such as severe immune adverse reactions, which reduce its use as a first-line treatment. This review examines BCG therapy's history, mechanisms, and current status, highlighting how nanotechnology and bioengineering are revitalizing its application. We discuss novel nanocarrier systems aimed at enhancing BCG's efficacy while mitigating specific side effects. These approaches promise improved tumor targeting, better drug loading, and an enhanced stimulation of anti-tumor immune responses. Key strategies involve using materials such as liposomes, polymers, and magnetic particles to encapsulate BCG or functional BCG cell wall components. Additionally, co-delivering BCG with chemotherapeutics enhances drug targeting and tumor-killing effects while reducing drug toxicity, with some studies even achieving synergistic effects. While most studies remain experimental, this research direction offers hope for overcoming BCG's limitations and advancing bladder cancer immunotherapy. Further elucidation of BCG's mechanisms and rigorous safety evaluations of new delivery systems will be crucial for translating these innovations into clinical practice.

Enhanced Intratumoral Delivery of Immunomodulator Monophosphoryl Lipid A through Hyperbranched Polyglycerol–Coated Biodegradable Nanoparticles

Immunomodulatory agents (IMA) have significant potential to enhance cancer treatment but have demonstrated limited efficacy beyond the preclinical setting due to poor pharmacokinetics and toxicity associated with systemic administration. On the other hand, when locally delivered, IMAs require repeated administration to optimize immune stimulation. To overcome these challenges, we encapsulated the toll-like receptor (TLR)4 agonist monophosphoryl lipid A (MPLA) within hyperbranched polyglycerol (HPG)-coated biodegradable nanoparticles (NP) engineered for gradual drug release from the nanoparticle core, resulting in a more persistent stimulation of anti-tumor immune responses while minimizing systemic side effects. In a model of malignant melanoma, we demonstrate that HPG-NP encapsulation significantly improves the antitumor efficacy of MPLA by enhancing its ability to remodel the tumor microenvironment (TME). Compared to free MPLA, HPG-NP-MPLA significantly increased the natural killer cell and cytotoxic T cell mediated antitumor immune response and tuned the tumor draining lymph nodes towards a T helper (Th)1 response. Furthermore, when combined with local delivery of a chemotherapeutic agent, HPG-NP-MPLA induces the conversion of an immunosuppressive TME to immunogenic TME and significantly improves survival.

A phase 1/2 study of EG-70 (detalimogene voraplasmid) intravesical monotherapy for patients with BCG-unresponsive non-muscle invasive bladder cancer with carcinoma in situ.

TPS4626 Background: High-risk non-muscle-invasive bladder cancer (NMIBC) is treated with adjuvant intravesical Bacille Calmette-Guérin (BCG). However, approximately 50% of patients experience recurrence and/or progression after BCG treatment and are considered unresponsive. EG-70 (detalimogene voraplasmid) is an investigational drug product that was specifically engineered for intravesical administration to elicit local stimulation of anti-tumor immune responses in the bladder and drive durable efficacy in patients with BCG-unresponsive NMIBC, while mitigating the risk of systemic toxicities from immune stimulation. The phase 1 (dose-escalation) part of the first-in-human LEGEND (NCT04752722) phase 1/2, open-label, multicenter study of EG-70 in patients with high-risk BCG-unresponsive NMIBC with carcinoma in situ (CIS) is complete: intravesical instillation of EG-70 was well tolerated with an overall complete response (CR) rate of 73%; and the recommended phase 2 dose (RP2D) was identified. Here we describe the ongoing phase 2 part of the study, which opened to enrollment in May 2023. Methods: Patient eligibility criteria: age ≥18 years; ECOG PS 0−2; BCG-unresponsive NMIBC with CIS, with or without resected coexisting papillary tumors, ineligible for, or have elected not to undergo, cystectomy; satisfactory bladder function with ability to retain study drug for ≥60 minutes. Prior checkpoint inhibitor treatment is allowed if completed within 30 days before study entry. Patients are treated with EG-70 at the RP2D (800 µg in 50 mL) by intravesical administration on weeks 1, 2, 5, and 6 of a 12-week cycle, for 4 cycles in one of two cohorts: BCG-unresponsive (Cohort 1); BCG-naïve or BCG-incompletely treated (Cohort 2). Patients in either cohort who exhibit stable disease (SD) or CR at week 12 will continue treatment until week 24; patients with progressive disease (PD) will discontinue treatment. Patients who experience or maintain CR at week 24 will receive additional cycles every 12 weeks until week 48; patients with SD or PD at week 24 will discontinue treatment. Patients with PD at any time after week 24 will discontinue treatment. Phase 2 primary objective: evaluate efficacy (CR rate at week 48) and safety of EG-70. Secondary objectives: evaluate progression-free survival, CR rate at 12, 24, 36 and 48 weeks, and duration of response. The study is being conducted in accordance with the International Conference on Harmonisation Good Clinical Practice guidelines and with the principles of the Declaration of Helsinki. All patients provide written informed consent. The ongoing, registration-enabling phase 2 portion of the LEGEND study is anticipated to recruit approximately 100 patients from sites in North America, Europe, and the Asia-Pacific region. Clinical trial information: NCT04752722 .

Abstract PR006: EG-70 (detalimogene voraplasmid), a novel, non-viral intravesical gene therapy for BCG-unresponsive non-muscle-invasive bladder cancer: Preclinical characterization and translation into the clinic

Abstract Background: EG-70 (detalimogene voraplasmid) is a novel, investigational, non-integrating, non-viral gene therapy specifically engineered to elicit local stimulation of anti-tumor immune response in the bladder and to drive durable efficacy in patients with BCG-unresponsive high-risk non-muscle-invasive bladder cancer (NMIBC), while mitigating the risk of systemic toxicities from immune stimulation. Previous preclinical data indicate that intravesical instillation (IVI) of EG-70 results in local expression of transgene products in murine and non-human primate models. Here we describe the latest preclinical data to support the mechanism of action of EG-70 and Phase 1 clinical study results for EG-70 in the treatment of BCG-unresponsive NMIBC. Methods: Preclinical: A murine surrogate formulation of EG-70 (mEG-70) was administered locally to the bladder by IVI in C57BL/6 mice. Efficacy was assessed in a luciferase-expressing MB49 model of orthotopic bladder cancer. Following confirmation of cancer cell implantation by in vivo imaging, mice received two weekly IVIs of mEG-70. Immune profiling was evaluated by assessing protein expression levels and cell compositions (via MSD, flow cytometry, and immunohistochemistry). Immune cell depletion studies were conducted using specific antibodies directed against CD4 or CD8 antigen to assess T-cell contribution to efficacy. Clinical: In a Phase 1/2 study in high-risk BCG-unresponsive NMIBC with carcinoma in situ (CIS) (LEGEND; NCT04752722), EG-70 was assessed in four separate dose groups. Results: Preclinical: In a mouse model of orthotopic bladder cancer, IVI of mEG-70 caused striking remodeling of the tumor microenvironment from an immunosuppressive phenotype to a pro-inflammatory milieu supportive of tumor clearance. This was demonstrated by a significant decrease in myeloid cells and IL-4 cytokine levels, an increase in NK-cells and T-cells, and an increase in pro-inflammatory cytokines in tumor tissue. Accordingly, administration of mEG-70 was associated with marked reduction in tumor burden and significant improvement of survival. The anti-tumor response was largely immune-mediated as demonstrated by the critical role of T-cells, durable clearance of tumors, and protection against subsequent tumorigenic re-challenge, both locally in the bladder as well as distally, after flank implantation. Clinical: Results from the Phase 1 portion of the LEGEND study show that IVI of EG-70 was well-tolerated in patients with high-risk BCG-unresponsive NMIBC with CIS across all dose levels, with an overall complete response rate of 73%. Conclusions: The latest preclinical findings demonstrate that EG-70 has the potential to deliver immunostimulatory payloads locally to the bladder. The mechanism of action described preclinically has been translated into the clinic, in the Phase 1 portion of the LEGEND study in patients with BCG-unresponsive NMIBC with CIS. Citation Format: Marie-Line Goulet, Shauna M Dauphinee, Daniel Veilleux, Kristine S Louis, David Lazure, Sarah Stevenson, Darius Bilimoria, Fazmina Zamzameer, Ximin Chen, Sébastien Sublemontier, Sahar Amirkhani, Carlos Fleet, Richard Bryce, Matthew Bui, Shreyas Joshi, Susan J. Kalota, Anthony Cheung, James Sullivan. EG-70 (detalimogene voraplasmid), a novel, non-viral intravesical gene therapy for BCG-unresponsive non-muscle-invasive bladder cancer: Preclinical characterization and translation into the clinic [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2024 May 17-20; Charlotte, NC. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(10_Suppl):Abstract nr PR006.

Expanding the Potential of Neoantigen Vaccines: Harnessing Bacille Calmette-Guérin Cell-Wall-Based Nanoscale Adjuvants for Enhanced Cancer Immunotherapy.

Personalized antitumor immunotherapy utilizing neoantigen vaccines holds great promise. However, the limited immunogenicity of existing recognized neoantigens and the inadequate stimulation of antitumor immune responses by conventional adjuvants pose significant challenges. To address these limitations, we developed a nanovaccine that combines a BCG bacterial cell wall skeleton (BCG-CWS) based nanoscale adjuvant (BCNA) with peptide neoantigens (M27 and M30). This integrated approach provides an efficient translational strategy for cancer immunotherapy. The BCNA nanovaccine, formulated with PLGA as an emulsifier, exhibits excellent biocompatibility and superior antigen presentation compared with conventional BCG-CWS adjuvants. Subcutaneous immunization with the BCNA-based nanovaccine effectively targets lymph nodes, eliciting robust innate and tumor-specific immune responses. Importantly, our findings demonstrate that BCNAs significantly enhance neoantigen immunogenicity while minimizing acute systemic toxicity. Furthermore, when combined with a mouse PD-L1 antibody, our strategy achieves complete tumor elimination in 60% of cases and prevents 25% of tumor growth in a melanoma mouse model. In conclusion, our BCNA-based nanovaccine represents a promising avenue for advancing personalized therapeutic neoantigen vaccines and holds significant implications for enhancing personalized immunotherapy and improving patient outcomes in the field of cancer treatment.

INNV-31. ADOPTING TUMOR TREATING FIELDS (TTFIELDS) THERAPY FOR GLIOBLASTOMA AND OTHER SOLID CANCERS: CHALLENGES AND OPPORTUNITIES

Abstract Tumor Treating Fields (TTFields) are alternating electric fields generated by a wearable medical device (NovoTTF-200A), delivered to the tumor target by arrays placed on the skin. These fields have multiple biological effects on tumor cells, including mitotic disruption, dysregulated DNA repair, antimigratory effects, and stimulation of antitumor immune response. TTFields therapy was approved for recurrent and newly diagnosed glioblastoma, based on the randomized, pivotal EF-11 and EF-14 studies, respectively. Data from both studies demonstrated favorable outcomes, sustained quality of life, and tolerable safety profile. Side effects are limited to mostly manageable, mild to moderate skin reactions with no increased systemic toxicity. TTFields therapy is also approved for pleural mesothelioma and has met the primary endpoint in the pivotal LUNAR study for metastatic non-small cell lung cancer patients. Despite extensive preclinical data, positive clinical study outcomes, and favorable real-world evidence, adoption of TTFields therapy remains tepid. Here we discuss potential causes and possible solutions to treatment barriers. Based on extensive surveys in the field, we have identified several potential reasons. The first challenge is the perception that open-label studies are less rigorous since sham devices are not used per protocol. The purpose of sham treatments in trials is to minimize placebo effects and/or investigator bias, but RANO criteria is designed to guard against just that. Secondly, dissemination of knowledge underlying innovative therapies often takes time. Unlike chemotherapy and radiotherapy, the mechanistic aspects of TTFields are not typically included in oncology training. Lastly, the benefits of TTFields therapy may be difficult to appreciate due to the required chronic use during maintenance. Therefore, education, additional bench research, and future clinical studies are important for a better adoption of this increasingly important oncological option.

Biomarkers and Immunotherapy for Colorectal Cancer

Colorectal cancer (CRC) is the second major cause of mortality from cancer globally. Most CRCs are sporadic and may be classified into three main genetic pathways: the chromosomal instability (CIN) pathway, the microsatellite instability (MSI) pathway and the CpG island methylator phenotype (CIMP) pathway, which are associated with genetic mutations or epigenetic alterations and have the possibility to intersect, thus making the treatment of CRC challenging. Immunotherapy has offered some promising insights by inducing antitumor immune responses, but its effectiveness is restricted to certain groups of CRC patients with specific characteristics. Several biomarkers have demonstrated their potentials to predict the outcomes of immunotherapy in individual patients. Some of them include the extent of tumor mutations (MMR/MSI, POLE/POLD1, KRAS), PDL-1 expression, pre-existing immunity and gut microbial compositions. Immune checkpoint inhibitors (ICIs-)-based immunotherapy is considered to be the relatively traditional immunotherapeutic strategy in the treatment of CRC. However, it mainly targets CRCs with defective mismatch repair (dMMR) mechanisms. The more recently developed immunotherapies include cancer vaccines (molecular-based, cell-based and vector-based vaccines) and adoptive cell therapy (ACT), which have the potential to further enhance the stimulation of antitumor immune responses. This review summarizes the predictive biomarkers that have the potential application in CRC treatment, and discusses the immunotherapeutic strategies targeting CRCs that have been developed or are currently under investigation.

Clinical results of a phase 1 study of intravesical EG-70 in patients with BCG-unresponsive NMIBC.

512 Background: enGene is developing non-viral gene therapy platforms to deliver nucleic acids (plasmids) to epithelial mucosal tissues such as urothelium of urinary bladder. EG-70 is a nanoparticle formulation of plasmids that activates both innate and adaptive immune responses to activate the immune system within the bladder. The plasmid encodes both IL-12 and activators of the innate immune receptor RIG-I. EG-70 is administered intravesically to elicit local stimulation of anti-tumor immune responses providing durable efficacy in high grade non-muscle invasive bladder cancer (NMIBC) while avoidingsystemic toxicities. Methods: In the Phase 1 study(LEGEND; NCT04752722), escalating doses of EG-70 were administered intravesically to patients with BCG-unresponsive Carcinoma in situ (CIS) NMIBC on weeks 1 and 2 or weeks 1, 2, 5, 6 of 12-week treatment cycle. At the week 12 assessment, patients with stable disease (SD) or complete response (CR), as assessed by urine cytology, cystoscopy, and bladder biopsy, were allowed electively to remain on EG-70 for up to 3 additional 12-week cycles. Results: To date, 19 patients have been treated. There have been no DLTs. AEs (48 GR1, 17 GR 2 and 1 GR3) have been largely consistent with urinary tract instrumentation, and were not dose related. Eighteen patients have completed one cycle of EG-70, and 67% have achieved CR. Fifteen patients with CR or SD at the end of cycle 1 elected to receive additional treatment cycles (continuation rate of 15/18 ( 83%)). Durable CRs were seen at all dose levels. Patients who receive additional cycles are followed for durability of response (Table). Complete Response. Conclusions: These results demonstrate the safety, tolerability and durable therapeutic potential of intravesical EG-70 in patients with BCG-unresponsive CIS. A Phase 2 study will proceed in 2023. Clinical trial information: NCT04752722 . [Table: see text]

LB998 Lymph node delivery of immunstimulatory agent monophosphoryl lipid A via bioadhesive nanoparticles in the treatment of cutaneous melanoma

Monophosphoryl lipid A (MPLA) is a low-toxicity derivative of LPS with immunomodulating properties. Nanoparticle (NP) encapsulation of immunomodulatory agents may allow for effective delivery to tumor sites as well as tumor draining lymph nodes (TDLN) and stimulation of anti-tumor immune responses while minimizing systemic side effects. Our bioadhesive NP (BNP) platform has been used for delivery of chemotherapy drugs with enhanced efficacy in pre-clinical models of solid tumors including SCC. To evaluate the cellular association and retention of BNP in TDLN, we used flow cytometry to assess immune cell uptake after in-vivo intratumoral (i.t.) delivery of Cy5-BNP to established PDVC57 SCC tumors.

Development of Molecular Mechanisms and Their Application on Oncolytic Newcastle Disease Virus in Cancer Therapy.

Cancer is caused by the destruction or mutation of cellular genetic materials induced by environmental or genetic factors. It is defined by uncontrolled cell proliferation and abnormality of the apoptotic pathways. The majority of human malignancies are characterized by distant metastasis and dissemination. Currently, the most common means of cancer treatment include surgery, radiotherapy, and chemotherapy, which usually damage healthy cells and cause toxicity in patients. Targeted therapy is an effective tumor treatment method with few side effects. At present, some targeted therapeutic drugs have achieved encouraging results in clinical studies, but finding an effective solution to improve the targeting and delivery efficiency of these drugs remains a challenge. In recent years, oncolytic viruses (OVs) have been used to direct the tumor-targeted therapy or immunotherapy. Newcastle disease virus (NDV) is a solid oncolytic agent capable of directly killing tumor cells and increasing tumor antigen exposure. Simultaneously, NDV can trigger the proliferation of tumor-specific immune cells and thus improve the therapeutic efficacy of NDV in cancer. Based on NDV’s inherent oncolytic activity and the stimulation of antitumor immune responses, the combination of NDV and other tumor therapy approaches can improve the antitumor efficacy while reducing drug toxicity, indicating a broad application potential. We discussed the biological properties of NDV, the antitumor molecular mechanisms of oncolytic NDV, and its application in the field of tumor therapy in this review. Furthermore, we presented new insights into the challenges that NDV will confront and suggestions for increasing NDV’s therapeutic efficacy in cancer.

Abstract 256: Dual A2aR/A2bR antagonism with etrumadenant (AB928) eliminates the suppressive effects of adenosine on immune and cancer cells in the tumor microenvironment

Abstract INTRODUCTION: Tumors employ many strategies to attenuate immune responses. High levels of extracellular adenosine generated in the tumor microenvironment engage A2a and A2b adenosine receptors on immune cells, resulting in immunosuppression. Expression of A2aR and A2bR can vary by cell type, with T cells predominantly expressing A2aR while myeloid cells express both A2aR and A2bR. We have previously shown that etrumadenant, a dual A2aR/A2bR antagonist, blocks the immunosuppressive effects of adenosine in immune cells and enhances anti-tumor immune responses in mouse syngeneic tumors. Using dual and selective adenosine receptor antagonists, we assessed the contribution of these receptors to adenosine-mediated phenotypes in immune and cancer cells. METHODS: Human CD8+ T cells were isolated from healthy human blood and activated using CD3/CD28/CD2 stimulation and cytokines were analyzed by cytokine bead array at 72 hours. Primary human dendritic cells (DC) were isolated from healthy blood and matured with LPS/IFN-γ for 24 hours. Cancer cell lines were purchased from ATCC. The adenosine analogue NECA was used to stimulate A2aR/A2bR-mediated signaling. RESULTS: Activated human CD8+ T cells stimulated in the presence of NECA showed suppression of activation markers (CD69) and cytokine production (IFN-γ, IL-2 and granzyme B). As expected, we observed similar rescue of this phenotype with both etrumadenant and an A2aR-specific antagonist owing to the sole expression of A2aR on T cells. In contrast, primary DC have comparable expression of A2aR and A2bR, suggesting that dual blockade may provide greater resistance to adenosine-mediated suppression than A2aR antagonism. Indeed, etrumadenant was able to attenuate the adenosine-mediated upregulation of IL-10 and enhance IL-12p70 production, whereas a comparable A2aR-specific antagonist showed no significant rescue versus NECA-stimulated controls. These observations may be extended to suppressive myeloid populations as well as tumor-resident macrophages and myeloid-derived suppressor cells isolated from mouse syngeneic tumors, which have very high expression of both A2aR and A2bR. RNA-sequencing identified a cassette of genes regulated by adenosine-signaling in these cells, which were largely reversed by etrumadenant. Finally, cultured human cancer cell lines have high expression of A2bR, which has been implicated in driving their tumorigenesis. Etrumadenant reversed adenosine-stimulated gene expression changes in non-small cell lung cancer cell lines, restoring enriched pathways driven by adenosine signaling. CONCLUSIONS: Taken together, these results show an important role for A2aR/A2bR in adenosine-mediated immunosuppression and provide a mechanistic rationale for stimulation of anti-tumor immune responses with the dual adenosine receptor antagonist etrumadenant. Citation Format: Sachie Marubayashi, Bindi Patel, Livia Yamashiro, Dana Piovesan, Sean Cho, Jenna Jeffrey, Manmohan Leleti, Jay Powers, Matt Walters, Daniel DiRenzo. Dual A2aR/A2bR antagonism with etrumadenant (AB928) eliminates the suppressive effects of adenosine on immune and cancer cells in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 256.

Tumor-immune ecosystem dynamics define an individual Radiation Immune Score to predict pan-cancer radiocurability.

Radiotherapy efficacy is the result of radiation-mediated cytotoxicity coupled with stimulation of antitumor immune responses. We develop an in silico 3-dimensional agent-based model of diverse tumor-immune ecosystems (TIES) represented as anti- or pro-tumor immune phenotypes. We validate the model in 10,469 patients across 31 tumor types by demonstrating that clinically detected tumors have pro-tumor TIES. We then quantify the likelihood radiation induces antitumor TIES shifts toward immune-mediated tumor elimination by developing the individual Radiation Immune Score (iRIS). We show iRIS distribution across 31 tumor types is consistent with the clinical effectiveness of radiotherapy, and in combination with a molecular radiosensitivity index (RSI) combines to predict pan-cancer radiocurability. We show that iRIS correlates with local control and survival in a separate cohort of 59 lung cancer patients treated with radiation. In combination, iRIS and RSI predict radiation-induced TIES shifts in individual patients and identify candidates for radiation de-escalation and treatment escalation. This is the first clinically and biologically validated computational model to simulate and predict pan-cancer response and outcomes via the perturbation of the TIES by radiotherapy.

Predictive Biomarkers of Response to Immunotherapy in Metastatic Renal Cell Cancer.

IntroductionIn the last decades, the therapeutic decision-making approach to metastatic renal cell cancer (mRCC) has dramatically changed thanks to the introduction in the treatment scenario of, first, anti-angiogenic agents and, afterward, immune-checkpoint inhibitors (ICIs). Immunotherapy is now the standard of care in pretreated mRCC patients and has recently entered even the first line setting. Nevertheless, in mRCC as well as in other tumor settings, a durable and clinically meaningful benefit from treatment with ICIs is not obtained for all patients treated. Therefore, the necessity to identify and validate predictive biomarkers of response to immunotherapy has emerged, in order to design the optimal treatment strategy for mRCC patients.DiscussionIn this review, we present and discuss the most promising predictive biomarkers of response to ICIs in mRCC with the recent data available. In details, the first marker that was investigated is the immunohistochemical expression of programmed death receptor ligand 1 (PD-L1), showing a negative prognostic role in mRCC, but the debate about its potential predictive value is still open. Additionally, the high heterogeneity in PD-L1 determination methods adds complexity to this issue. Second, the tumor mutational or neoantigen burden is an emerging biomarker of increased response to immunotherapy, hypothesizing that the higher the TMB, the higher is the production of neoantigens, and thus the stimulation of anti-tumor immune response, even though controversial results have been obtained. Third, the tumor microenvironment, namely the different populations of the immune infiltrate, plays a key role in tumor progression and in the response to immunotherapy. Finally, several studies have collected evidence on the potential association of the occurrence of immune-related adverse events (irAEs) with the benefit from ICIs, first in non-small cell lung cancer (NSCLC) and melanoma, and recently even in mRCC.ConclusionSeveral promising biomarkers of response to immunotherapy with ICIs have been identified, though without conclusive results upon their potential predictive value in mRCC. Therefore, the results of the exploratory analyses of the recently presented first-line trials and hopefully of future prospective, biomarker-driven studies could provide useful tools to be applied in the everyday clinical practice.

Abstract B85: Anticancer efficacy of a novel immune-stimulating oncolytic virus: VG161 in gastrointestinal cancers

Abstract Oncolytic viruses (OVs) are the wild-type or genomic modified viruses, which can specifically replicate in cancer cells but not in normal cells. They cause cancer cell lysis and more importantly, their replication in tumor cells induces an antitumor immune response from the host. As synergistic stimulation of antitumor immune response requires multiple immune-regulatory factors, OVs armed with multiple immune-modulating factors are of high potential in cancer immunotherapy. We have constructed a novel herpes simplex virus type-1 virus (HSV-1), VG161, that is armed with IL12, IL15, and a unique PDL-1 peptide blocker. The aim of this study is to investigate the anticancer efficacy of VG161 in gastrointestinal (GI) cancers including gastric, hepatic, and colorectal cancers. The immune-stimulating activities in tumor-bearing immune competent mice were also demonstrated. VG161 was given to the tumor-bearing animals by intratumor injection (5 × 106-5 × 107 PFU/animal, once a day for 3-5 days). Antitumor activity of VG161 was tested in both immune-deficient mice as well as in immune-competent mice. Oncolytic activity of VG161 was demonstrated in human gastric (SGC-7901), hepatic (patient-derived xenograft, PDX), and colorectal (LS174T) cancer-bearing nude mice as the human tumors are susceptible to HSV infection and the immune system is compromised in those models. To determine the antitumor immune response activated by VG161, colorectal cancer (CT26) syngeneic model was used in immune competent animals and T cell subpopulation analysis, ELISPOT, and tumor rechallenge assay was applied to measure specific antitumor immunity. VG161 caused complete tumor eradication in PDX and CT26 tumor models and significantly inhibited tumor growth in SGC-7901 and LS174T models. All animals treated with VG161 survived for many months till sacrificed. In the CT26 model, no tumor could be found after rechallenging with the same tumor cells. The number of CD8+ tumor infiltrated T cells was significantly increased, and systemic specific anticancer immunity was confirmed by ELISPOT assay on T cells isolated from spleen. VG161 is a novel oncolytic virus that is both strong in oncolysis and stimulating antitumor immunity for GI cancers. Intratumorally expressing multiple immune-regulatory factors by an oncolytic virus may significantly change the GI tumor immune microenvironment and stimulate anticancer immunity, to further enhance the efficacy of the oncolytic virus. Citation Format: Ronghua Zhao, Jun Ding, Tianchi Liu, Shuyun Liu, Dmitry Chouljenko, Yanal Murad, Erica Lee, Guoyu Liu, Luke Bu, William Jia. Anticancer efficacy of a novel immune-stimulating oncolytic virus: VG161 in gastrointestinal cancers [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B85.

Abstract 3231: Oncolytic immunotherapy with PD-1 blockade and telomerase-specific oncolytic adenovirus in osteosarcoma

Abstract Background: Osteosarcoma (OS) is the most frequent primary malignant tumor of bone in children and adolescents. Although immune checkpoint inhibitor, anti-programmed death protein 1 (PD-1) antibody, has dramatically improved the clinical outcome in some cancer patients, OS patients are less sensitive to PD-1 blockade due to poor immune responses. Recently, oncolytic virotherapy has been shown to stimulate the immune system through induction of immunogenic cell death (ICD). We recently developed a RGD fiber-modified telomerase-specific oncolytic adenovirus OBP-502, which can enter into tumor cells by binding to cell surface integrin and induce oncolytic cell death in a telomerase-dependent manner. In this study, we assessed the in vitro and in vivo antitumor efficacy of combination therapy with PD-1 blockade and OBP-502 in OS cells. Methods: We used 2 murine OS cell lines, K7M2 and NHOS. The expression of PD-L1, coxsackie and adenovirus receptor (CAR), and integrin on the cell surface was analyzed by flow cytometric analysis. We analyzed the in vitro antitumor effect of OBP-502 using XTT assay and western blot analysis. Virus-induced ICD was assessed by analyzing the level of extracellular ATP and high-mobility group box protein B1 (HMGB1). To evaluate the therapeutic potential of oncolytic immunotherapy, we investigated the in vivo antitumor effect of combination therapy with anti-PD-1 antibody and OBP-502 using a subcutaneous K7M2 xenograft tumor model. Moreover, the number of tumor-infiltrating CD8+, CD4+ and Foxp3+ T cells was analyzed by immunohistochemistry. Results: Flow cytometric analysis demonstrated that K7M2 and NHOS cells had the expression of PD-L1 and integrin, but not CAR. XTT assay showed that OBP-502 efficiently suppressed the viability of K7M2 and NHOS cells in a dose-dependent manner. Western blot analysis revealed that OBP-502 induced the apoptosis-related cell death in K7M2 and NHOS cells. ELISA assay demonstrated that OBP-502 significantly increased the level of extracellular ATP and HMGB1 in K7M2 and NHOS cells. In vivo experiment using a subcutaneous K7M2 xenograft tumor model showed that combination of anti-PD-1 antibody and OBP-502 significantly reduced tumor growth compared to mock treatment or monotherapy. Immunohistochemical analysis revealed that OBP-502 significantly increased the number of tumor-infiltrating CD8+ T cells compared to mock treatment or monotherapy. By contrast, OBP-502 did not affect the number of CD4+ and Foxp3+ T cells in tumor tissues. Conclusion: These results suggest that oncolytic immunotherapy with PD-1 blockade and telomerase-specific oncolytic adenovirus is a promising antitumor strategy to promote the therapeutic potential of PD-1 blockade in OS through stimulation of antitumor immune response. Citation Format: Koji Demiya, Hiroshi Tazawa, Yusuke Mochizuki, Miho Kure, Joe Hasei, Toshiyuki Kunisada, Yasuo Urata, Toshifumi Ozaki, Toshiyoshi Fujiwara. Oncolytic immunotherapy with PD-1 blockade and telomerase-specific oncolytic adenovirus in osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3231.

Photo-triggered gadofullerene: enhanced cancer therapy by combining tumor vascular disruption and stimulation of anti-tumor immune responses

Efficient treatment of primary tumor and preventing cancer metastasis present intriguing alternatives to cancer therapy. Herein, for the first time, we reported the photo-triggered nano-gadofullerene (Gd@C82-Ala, abbreviated Gd-Ala) induced malignant tumor vascular disruption by shortening the light interval between Gd-Ala administration and light illumination, where oxygen in blood vessels was employed efficiently to produce cytotoxic reactive oxygen species (ROS). The produced ROS could not only destroy the tumor cells but also devastate the vascular endothelial cells corresponding to the loss of intercellular junctions and vessels disruption. Notably, the irradiated Gd-Ala could enhance dendritic cells (DCs) maturation, which further secreted tumor necrosis factor-α (TNF-α) and interleukin-12 (IL)-12, and then activated T lymphocytes by up-regulation of cluster of differentiation CD4+ and CD8+ T lymphocytes. Furthermore, the down-regulation of matrix metalloprotein 2 (MMP2) and MMP9 also reduce the rate of tumor metastasis. This work explored a new biomedical application of gadofullerene, thereby providing a smart carbon nanomaterial candidate for tumor ablation and inhibition of cancer metastasis.

Photodynamic therapy for cancer: Role of natural products.

Photodynamic therapy (PDT) is a promising modality for the treatment of cancer. PDT involves administering a photosensitizing dye, i.e. photosensitizer, that selectively accumulates in tumors, and shining a light source on the lesion with a wavelength matching the absorption spectrum of the photosensitizer, that exerts a cytotoxic effect after excitation. The reactive oxygen species produced during PDT are responsible for the oxidation of biomolecules, which in turn cause cell death and the necrosis of malignant tissue. PDT is a multi-factorial process that generally involves apoptotic death of the tumor cells, degeneration of the tumor vasculature, stimulation of anti-tumor immune response, and induction of inflammatory reactions in the illuminated lesion. Numerous compounds with photosensitizing activity have been introduced commercially. Although many papers have been published with regard to PDT in the last decade, there has been relatively little focus on natural medicinal plant extracts and compounds derived therefrom. Herbal plants and their extracts are natural substances, and in comparison with synthetic chemicals are considered "green". This review focuses on the different mechanisms of PDT and discusses the role of various plant extracts and natural compounds either alone or in combination for carrying out PDT on different types of cancers.

Virus-Based Immunotherapy of Glioblastoma.

Glioblastoma (GBM) is the most common type of primary brain tumor in adults. Despite recent advances in cancer therapy, including the breakthrough of immunotherapy, the prognosis of GBM patients remains dismal. One of the new promising ways to therapeutically tackle the immunosuppressive GBM microenvironment is the use of engineered viruses that kill tumor cells via direct oncolysis and via stimulation of antitumor immune responses. In this review, we focus on recently published results of phase I/II clinical trials with different oncolytic viruses and the new interesting findings in preclinical models. From syngeneic preclinical GBM models, it seems evident that oncolytic virus-mediated destruction of GBM tissue coupled with strong adjuvant effect, provided by the robust stimulation of innate antiviral immune responses and adaptive anti-tumor T cell responses, can be harnessed as potent immunotherapy against GBM. Although clinical testing of oncolytic viruses against GBM is at an early stage, the promising results from these trials give hope for the effective treatment of GBM in the near future.

Current Status of Messenger RNA Delivery Systems.

Messenger RNA is emerging as a highly versatile biological construct for creation of impactful medicines. mRNA vaccines directed toward infectious disease and cancer are in clinical development with encouraging early reads on tolerability and efficacy. The use of mRNA to direct intense but transient expression of paracrine factors is finding utility in reprogramming progenitor cells for wound healing and cardiac regeneration and for stimulation of antitumor immune responses, at least preclinically as we await clinical results. The use of mRNA for prolonged and repeated expression of proteins and enzymes to treat rare, typically monogenic disease is nearing clinical entry. These uses of mRNA require delivery solutions, and the application of and improvement to existing nanoparticle nucleic acid delivery systems have jump started the pace of development and reenergized the field of particle based nucleic acid delivery. The current status of mRNA delivery is reviewed in this article with an eye toward clinical tractability.