Oncolytic virotherapy. Nat Biotechnol. 2012;30:658-670. [PMID: 22781695 PMCID: PMC3888062 DOI: 10.1038/nbt.2287]

Epigenetic modulation by oncolytic viruses: Implications for cancer therapeutic efficacy

Among various therapeutic agents, Oncolytic Viruses (OVs) are the most promising anticancer therapeutics because of their tumor-specific targeting and capability to mediate an antitumor immune response. In this review, we will discuss how epigenetic reprogramming of both the host and tumor can facilitate increased sensitivity of tumors to OV therapy. OVs infect tumor cells and modulate epigenetic landscapes, including DNA methylation, histone modifications, and chromatin remodeling, as well as non-coding RNA expression that consequently induces immune responses. These epigenetic changes, including hypermethylation of tumor-associated antigen genes and chromatin accessibility alterations, enhance the immunogenicity of tumors to facilitate recognition by the immune system. Here, we provide a general review addressing this question by discussing the potential benefits of combining OVs with epigenetic drugs to combat resistance and promote treatment efficacy. This information illustrates the importance of personalized OV therapy regarding epigenome in individual profiles and transitions. Still, it extends difficulty in inducing with acquisitions of viral-induced changes globally and making translatable steps by creating cancer-specific predictive treatment models.

Exploring neuroblastoma's cellular microenvironment: A novel approach using cellular automata to model Celyvir treatment

Neuroblastoma is a significant health concern in children, as it is one of the most common types of cancer among this age group and is associated with poor survival rates. Currently, there are no effective therapies that significantly improve outcomes for these patients. This study explores the efficacy of Celyvir - an advanced therapy comprising mesenchymal stem cells (MSCs) carrying the oncolytic virus ICOVIR 5 - against neuroblastoma, by means of an individual-based model. A probabilistic cellular automaton was developed to implement the dynamic interactions between neuroblastoma cells, T lymphocytes, and the therapeutic agent Celyvir. The model examines various sizes, shapes, and positions of the tumour within a lattice, along with different infection probabilities associated with the action of Celyvir and various treatment schedules. This analysis identifies the most influential infection probabilities according to the cellular automaton model, and demonstrates that different treatment regimens can effectively eradicate the tumour, in contrast to standard clinical approaches. Additionally, Kaplan-Meier curves have been generated to assess different treatment schedules under specific tumour scenarios, highlighting the importance of precise treatment scheduling to optimise therapeutic outcomes. This study provides insights into the potential of Celyvir in neuroblastoma treatment, emphasising the need to understand tumour dynamics and strategically implement treatment schemes to improve clinical outcomes.

Multiple primary malignancies and gut microbiome

BACKGROUND

Multiple primary malignancies (MPM) are two or more independent primary malignancies. Recently, the relationship between microbiome and various tumors has been gradually focused on.

OBJECTIVE

To describe the relationship between MPM patients (MPMs) and gut microbiome.

METHODS

A total of 27 MPMs, 30 colorectal cancer patients (CRCs), and 30 healthy individuals were included to obtain metagenomic sequencing data. The knowledge graphs of gut bacteria and enteroviruses were plotted based on metagenomics. Wilcoxon rank-sum test was used to screen the characteristic gut microbiome.

RESULTS

The knowledge graph of gut microbiome in MPM patients was plotted. A total of 26 different gut bacteria, including Dialister, Fecalibacterium and Mediterraneibacter, were found between MPMs and healthy individuals. Twenty gut bacteria, including Parvimonas, Dialister and Mediterraneibacter, were more abundant in MPM complicated by CRC compared with CRCs. Twenty-one different enterovirus, including Triavirus, Punavirus and Lilyvirus, were screened between MPMs and healthy individuals. Triavirus, Punavirus and Lilyvirus were less abundant in MPM than healthy individuals. The abundance of Triavirus, Punavirus and Lilyvirus in CRC patients were also lower than MPM complicated by CRC patients.

CONCLUSION

The knowledge graph of gut microbiome in MPM patients was plotted. It may provide basic data support for future research of MPM.

Mapping the landscape of gastric cancer immunotherapy: Bibliometric insights into advances and hotspots

BACKGROUND

Immunotherapy has surfaced as a promising therapeutic modality for gastric cancer (GC). A comprehensive review of advancements, current status, and research trends in GC immunotherapy is essential to inform future investigative efforts.

AIM

To delineate the trends, advancements, and focal points in immunotherapy for GC.

METHODS

We performed a bibliometric analysis of 2906 articles in English concerning GC immunotherapy published from 2000 to December 20, 2023, indexed in the Web of Science Core Collection. Data analysis and visualization were facilitated by CiteSpace (6.1.6R), VOSviewer v.1.6.17, and GraphPad Prism v8.0.2.

RESULTS

There has been an increase in the annual publication rate of GC immunotherapy research. China leads in publication volume, while the United States demonstrates the highest citation impact. Fudan University is notable for its citation frequency and publication output. Co-citation analysis and keyword frequency revealed and highlighted a focus on GC prognosis, the tumor microenvironment (TME), and integrative immunotherapy with targeted therapy. Emerging research areas include gastroesophageal junction cancer, adoptive immunotherapy, and the role of Treg cell in immunotherapy.

CONCLUSION

GC immunotherapy research is an expanding field attracting considerable scientific interest. With the clinical adoption of immunotherapy in GC, the primary goals are to enhance treatment efficacy and patient outcomes. Unlike hematological malignancies, GC's solid TME presents distinct immunological challenges that may attenuate the cytotoxic effects of immune cells on cancer cells. For instance, although CAR-T therapy is effective in hematological malignancies, it has underperformed in GC settings. Current research is centered on overcoming immunosuppression within the TME, with a focus on combinations of targeted therapy, adoptive immunotherapy, Treg cell dynamics, and precise prognosis prediction in immunotherapy. Additionally, immunotherapy's role in treating gastroesophageal junction cancer has become a novel research focus.

A novel oncolytic vaccinia virus with multiple gene modifications involved in viral replication and maturation increases safety for intravenous administration while maintaining proliferative potential in cancer cells

To generate a novel oncolytic vaccinia virus with improved safety and productivity, the genome of smallpox vaccine strain LC16m8 was modified by a bacterial artificial chromosome system. By using LC16m8, a replicating virus homologous to the target virus, as a helper virus for the bacterial artificial chromosome system, we successfully recovered genome-edited infectious viruses. Oncolytic viruses with limited growth in normal cells were obtained by deleting the genes for vaccinia virus growth factor (VGF), extracellular signal-regulated kinase-activating protein (O1L), and ribonucleotide reductase (RNR) present in the viral genome. Furthermore, the amino acid residues of seven proteins involved in extracellular enveloped virus virion formation were replaced to the IHD-J strain sequence, which is known to highly express extracellular enveloped virus. In cultured cancer cells (HeLa), these modified viruses showed cytotoxicity and increased productivity, but it was confirmed that the cytotoxicity was suppressed in normal cells (normal human dermal fibroblasts). For in vivo safety evaluation, a modified virus (MD-RVV-ΔRR-EEV6) in which the VGF, O1L, and RNR genes of LC16m8 were deleted and the genes of six extracellular enveloped virus-associated proteins were replaced with sequences derived from IHD-J strain, and another modified virus (MD-RVV) lacking only the VGF and O1L were administered intravenously to severe combined immunodeficiency mice. In the MD-RVV administration, animals in all dose groups died by 40 days after virus administration. On the other hand, after MD-RVV-ΔRR-EEV6 administration, 3 out of 5 animals in the high and medium dose groups and all animals in the low dose group were still alive by day 71, the end of the observation period. These results demonstrate that genome editing of oncolytic vaccinia virus can delete genes involved in viral replication to improve safety in normal cells, while replacing genes involved in maturation improves proliferative potential in cancer cells.

Ferroptosis enhances the therapeutic potential of oncolytic adenoviruses KD01 against cancer

Oncolytic virotherapy has emerged as a promising strategy for cancer treatment by selectively targeting and lysing tumor cells. However, its efficacy is often limited in certain tumor types due to multiple factors. This study explores the combination of oncolytic adenoviruses with Erastin, a potent ferroptosis inducer, to enhance antitumor efficacy in oncolytic virus-insensitive cancer cell lines. In vitro experiments demonstrated that Erastin significantly increased the cytotoxicity of oncolytic virotherapy, leading to greater inhibition of cell proliferation and elevated rates of cell death compared to monotherapies. The combination treatment further promoted ferroptosis, as evidenced by increased reactive oxygen species (ROS) levels, enhanced lipid peroxidation, and disrupted redox homeostasis. RNA sequencing identified the downregulation of Dickkopf-1 (DKK1) as a key mediator of the enhanced ferroptotic effect. Restoring the expression of DKK1 partially mitigated the cytotoxic effects of the combination therapy, highlighting its crucial role in mediating the enhanced ferroptosis-induced oncolytic virotherapy efficacy. In vivo studies further validated these findings, demonstrating that the combined treatment significantly reduced tumor growth without inducing notable toxicity. This novel therapeutic approach has great potential to enhance the efficacy of oncolytic virotherapy in cancers resistant to oncolytic viruses by inducing ferroptosis. Further investigation in clinically relevant models is warranted to fully elucidate the underlying mechanisms and to optimize this combination strategy for potential clinical applications.

Oncolytic Virus Targeted Therapy for Glioma via Intravenous Delivery

Glioma, the deadly primary intracranial tumor, poses challenges in clinical treatment due to its infiltrative growth and resistance to radiation. Oncolytic virus therapy holds potential for the treatment of malignant gliomas, but its application is impeded by the requirement for intracranial injections due to the presence of blood-brain barrier (BBB). In this study, to overcome this limitation, the study develops a nanocapsule encapsulating the recombinant oncolytic virus EV-A71-miR124T, enabling the treatment of glioma through intravenous administration. It is demonstrated that the nanocapsule can cross the BBB and selectively release oncolytic virus at the tumor site, resulting in targeted and specific killing of glioma cells. In mice with implanted intracranial orthotopic gliomas, intravenous administration of the nanocapsule suppresses tumor growth and significantly extends survival time. Consequently, the study establishes an effective treatment method for malignant gliomas using an oncolytic virus nanocapsule through intravenous administration. These findings provide a new strategy for oncolytic virus therapy in glioma treatment and offer perspectives for targeted therapies of other brain tumors and diseases.

Characterisation and Sensitivity of a Canine Mast Cell Tumour Line to Oncolytic Viruses

Canine mast cell tumours (MCTs) are one of the most common skin cancers of dogs. Surgical removal is the primary treatment, but recurrence and metastasis can occur even with low-grade tumours. As a result, new treatment strategies are being sought. We tested the potential of several oncolytic viruses (OVs) to infect and kill a cell line isolated from a canine MCT. Employing a resazurin-based metabolic assay and flow cytometry technology, we used recombinant vesicular stomatitis virus (rVSV-Δm51), avian orthoavulavirus-1 (AOaV-1), and Orf viruses in our assessment. Our study aimed to evaluate the potential of oncolytic virotherapy in treating canine cancers. We found that MCT-1 cells showed different sensitivities to the OVs, with rVSV-Δm51 showing the most promising results in vitro. These findings suggest that further investigation into using OVs for treating canine MCTs is needed, although clinical efficacy is yet to be determined.

Current Landscape and Future Directions in Cancer Immunotherapy: Therapies, Trials, and Challenges

Cancer remains a leading global health challenge, placing immense burdens on individuals and healthcare systems. Despite advancements in traditional treatments, significant limitations persist, including treatment resistance, severe side effects, and disease recurrence. Immunotherapy has emerged as a promising alternative, leveraging the immune system to target and eliminate tumour cells. However, challenges such as immunotherapy resistance, patient response variability, and the need for improved biomarkers limit its widespread success. This review provides a comprehensive analysis of the current landscape of cancer immunotherapy, highlighting both FDA-approved therapies and novel approaches in clinical development. It explores immune checkpoint inhibitors, cell and gene therapies, monoclonal antibodies, and nanotechnology-driven strategies, offering insights into their mechanisms, efficacy, and limitations. By integrating emerging research and clinical advancements, this review underscores the need for continued innovation to optimise cancer immunotherapy and overcome existing treatment barriers.

Decorin: matrix-based pan-cancer tumor suppressor

Studies have shown that decorin is a potent pan-cancer tumor suppressor that is under-expressed in most cancers. Decorin interacts with receptor tyrosine kinases and functions as a pan-receptor tyrosine kinase inhibitor, thereby suppressing oncogenic signals. Decorin deficiency promotes epithelial-to-mesenchymal transition and enhances cancer dissemination and metastasis. According to recent GLOBOCAN estimates, the most common cancers worldwide are breast, lung, prostate, colorectal, skin (non-melanoma), and stomach. Considering the burden of rising cancer incidence and the importance of discovering novel molecular markers and potential therapeutic agents for cancer management, we have outlined the possible expressional and clinicopathological significance of decorin in major cancers based on available pre-clinical and clinical studies. Measuring plasma decorin is a minimally invasive technique, and human studies have shown that it is useful in predicting clinical outcomes in cancer though it needs further validation. Oncolytic virus-mediated decorin gene transfer has shown significant anti-tumorigenic effects in pre-clinical studies, though its implication in human subjects is yet to be understood. Exogenous decorin delivery in experimental studies has been shown to mitigate cancer growth, but its therapeutic efficacy and safety are poorly understood. Future research is required to translate the tumor-suppressive action of decorin observed in preclinical experiments to therapeutic interventions in human subjects.

Tumor microbiome: roles in tumor initiation, progression, and therapy

Over the past few years, the tumor microbiome is increasingly recognized for its multifaceted involvement in cancer initiation, progression, and metastasis. With the application of 16S ribosomal ribonucleic acid (16S rRNA) sequencing, the intratumoral microbiome, also referred to as tumor-intrinsic or tumor-resident microbiome, has also been found to play a significant role in the tumor microenvironment (TME). Understanding their complex functions is critical for identifying new therapeutic avenues and improving treatment outcomes. This review first summarizes the origins and composition of these microbial communities, emphasizing their adapted diversity across a diverse range of tumor types and stages. Moreover, we outline the general mechanisms by which specific microbes induce tumor initiation, including the activation of carcinogenic pathways, deoxyribonucleic acid (DNA) damage, epigenetic modifications, and chronic inflammation. We further propose the tumor microbiome may evade immunity and promote angiogenesis to support tumor progression, while uncovering specific microbial influences on each step of the metastatic cascade, such as invasion, circulation, and seeding in secondary sites. Additionally, tumor microbiome is closely associated with drug resistance and influences therapeutic efficacy by modulating immune responses, drug metabolism, and apoptotic pathways. Furthermore, we explore innovative microbe-based therapeutic strategies, such as engineered bacteria, oncolytic virotherapy, and other modalities aimed at enhancing immunotherapeutic efficacy, paving the way for microbiome-centered cancer treatment frameworks.

Genetic advancements in breast cancer treatment: a review

Breast cancer (BC) remains a leading cause of cancer-related deaths among women globally, highlighting the urgent need for more effective and targeted therapies. Traditional treatments, including surgery, chemotherapy, and radiation, face limitations such as drug resistance, metastasis, and severe side effects. Recent advancements in gene therapy, particularly CRISPR/Cas9 technology and Oncolytic Virotherapy (OVT), are transforming the BC treatment landscape. CRISPR/Cas9 enables precise gene editing to correct mutations in oncogenes like HER2 and MYC, directly addressing tumor growth and immune evasion. Simultaneously, OVT leverages genetically engineered viruses to selectively destroy cancer cells and stimulate robust antitumor immune responses. Despite their potential, gene therapies face challenges, including off-target effects, delivery issues, and ethical concerns. Innovations in delivery systems, combination strategies, and integrating gene therapy with existing treatments offer promising solutions to overcome these barriers. Personalized medicine, guided by genomic profiling, further enhances treatment precision by identifying patient-specific mutations, such as BRCA1 and BRCA2, allowing for more tailored and effective interventions. As research progresses, the constructive interaction between gene therapy, immunotherapy, and traditional approaches is paving the way for groundbreaking advancements in BC care. Continued collaboration between researchers and clinicians is essential to translate these innovations into clinical practice, ultimately improving BC patients' survival rates and quality of life.

Oncolytic senecavirus A in tumor immunotherapy: Mechanisms, progress, and future directions

Oncolytic virotherapy has emerged as a promising immunotherapy strategy against cancer. As the first picornavirus tested in humans for its oncolytic potential, Senecavirus A (SVA) possesses several advantageous features, including its small size, rapid replication, and ability to penetrate the vascular system of solid tumors, allowing for the specific targeting and lysis of tumor cells. Additionally, SVA does not integrate into the host genome, thus avoiding potential genomic damage, and it lacks oncogenes or other virulence genes. Importantly, no significant pathogenic effects have been observed in humans or companion animals. Due to its simple genetic structure, SVA is amenable to various genetic modifications, allowing it to carry exogenous genes to further enhance tumor therapy. This review summarizes current knowledge of SVA's mechanisms of action and its progress in oncolytic therapy research, while also addressing the challenges and future directions.

From infection to remedy: Harnessing oncolytic viruses in cancer treatment

Oncolytic virus (OV) mediated immunotherapy is one of the recent techniques used to treat higher grade cancers where conventional therapies like chemotherapy, radiation fail. OVs as a therapeutic tool show high efficacy and fewer side effects than conventional methods as supported by multiple preclinical and clinical studies since they are engineered to target tumours. In this chapter, we discuss the modifications in viruses to make them oncolytic, types of strains commonly administered, mechanisms employed by viruses to specifically target and eradicate malignancy and progress achieved as reported in case studies (preclinical and clinical trials). OVs also face some unique challenges with respect to the malignancy being treated and the varied pathogen exposure of the patients, which is also highlighted here. Since pathogen exposure varies according to population dynamics worldwide, chances of generating a non-specific recall response to an OV cannot be negated. Lastly, the future perspectives and ongoing practises of combination therapies are discussed as they provide a leading edge over monotherapies in terms of tumour clearance, blocking metastasis and enhancing patient survival. Efforts undertaken to overcome current challenges are also highlighted.

Enhancing precision in cancer treatment: the role of gene therapy and immune modulation in oncology

Gene therapy has long been a cornerstone in the treatment of rare diseases and genetic disorders, offering targeted solutions to conditions once considered untreatable. As the field advances, its transformative potential is now expanding into oncology, where personalized therapies address the genetic and immune-related complexities of cancer. This review highlights innovative therapeutic strategies, including gene replacement, gene silencing, oncolytic virotherapy, CAR-T cell therapy, and CRISPR-Cas9 gene editing, with a focus on their application in both hematologic malignancies and solid tumors. CRISPR-Cas9, a revolutionary tool in precision medicine, enables precise editing of cancer-driving mutations, enhancing immune responses and disrupting tumor growth mechanisms. Additionally, emerging approaches target ferroptosis-a regulated, iron-dependent form of cell death-offering new possibilities for selectively inducing tumor cell death in resistant cancers. Despite significant breakthroughs, challenges such as tumor heterogeneity, immune evasion, and the immunosuppressive tumor microenvironment (TME) remain. To overcome these barriers, novel approaches like dual-targeting, armored CAR-T cells, and combination therapies with immune checkpoint inhibitors and ferroptosis inducers are being explored. Additionally, the rise of allogeneic "off-the-shelf" CAR-T therapies offers scalable and more accessible treatment options. The regulatory landscape is evolving to accommodate these advancements, with frameworks like RMAT (Regenerative Medicine Advanced Therapy) in the U.S. and ATMP (Advanced Therapy Medicinal Products) in Europe fast-tracking the approval of gene therapies. However, ethical considerations surrounding CRISPR-based gene editing-such as off-target effects, germline editing, and ensuring equitable access-remain at the forefront, requiring ongoing ethical oversight. Advances in non-viral delivery systems, such as lipid nanoparticles (LNPs) and exosomes, are improving the safety and efficacy of gene therapies. By integrating these innovations with combination therapies and addressing regulatory and ethical concerns, gene therapy is poised to revolutionize cancer treatment, providing durable, effective, and personalized solutions for both hematologic and solid tumors.

Engineered bacteria launch and control an oncolytic virus

The ability of bacteria and viruses to selectively replicate in tumors has led to synthetic engineering of new microbial therapies. Here we design a cooperative strategy whereby S. typhimurium bacteria transcribe and deliver the Senecavirus A RNA genome inside host cells, launching a potent oncolytic viral infection. "Encapsidated" by bacteria, the viral genome can further bypass circulating antiviral antibodies to reach the tumor and initiate replication and spread within immune mice. Finally, we engineer the virus to require a bacterially delivered protease to achieve virion maturation, demonstrating bacterial control over the virus. This work extends bacterially delivered therapeutics to viral genomes, and shows how a consortium of microbes can achieve a cooperative aim.

The guided fire from within: intratumoral administration of mRNA-based vaccines to mobilize memory immunity and direct immune responses against pathogen to target solid tumors

We investigated a novel cancer immunotherapy strategy that effectively suppresses tumor growth in multiple solid tumor models and significantly extends the lifespan of tumor-bearing mice by introducing pathogen antigens into tumors via mRNA-lipid nanoparticles. The pre-existing immunity against the pathogen antigen can significantly enhance the efficacy of this approach. In mice previously immunized with BNT162b2, an mRNA-based COVID-19 vaccine encoding the spike protein of the SARS-CoV-2 virus, intratumoral injections of the same vaccine efficiently tagged the tumor cells with mRNA-expressed spike protein. This action rapidly mobilized the pre-existing memory immunity against SARS-CoV-2 to kill the cancer cells displaying the spike protein, while concurrently reprogramming the tumor microenvironment (TME) by attracting immune cells. The partial elimination of tumor cells in a normalized TME further triggered extensive tumor antigen-specific T cell responses through antigen spreading, eventually resulting in potent and systemic tumor-targeting immune responses. Moreover, combining BNT162b2 treatment with anti-PD-L1 therapy yielded a more substantial therapeutic impact, even in "cold tumor" types that are typically less responsive to treatment. Given that the majority of the global population has acquired memory immunity against various pathogens through infection or vaccination, we believe that, in addition to utilizing the widely held immune memory against SARS-CoV-2 via COVID-19 vaccine, mRNA vaccines against other pathogens, such as Hepatitis B Virus (HBV), Common Human Coronaviruses (HCoVs), and the influenza virus, could be rapidly transitioned into clinical use and holds great promise in treating different types of cancer. The extensive selection of pathogen antigens expands therapeutic opportunities and may also overcome potential drug resistance.

Focused Ultrasound in Cancer Immunotherapy: A Review of Mechanisms and Applications

Ultrasound is well-perceived for its diagnostic application. Meanwhile, ultrasound, especially focused ultrasound (FUS), has also demonstrated therapeutic capabilities, such as thermal tissue ablation, hyperthermia, and mechanical tissue ablation, making it a viable therapeutic approach for cancer treatment. Cancer immunotherapy is an emerging cancer treatment approach that boosts the immune system to fight cancer, and it has also exhibited enhanced effectiveness in treating previously considered untreatable conditions. Currently, cancer immunotherapy is regarded as one of the four pillars of cancer treatment because it has fewer adverse effects than radiation and chemotherapy. In recent years, the unique capabilities of FUS in ablating tumors, regulating the immune system, and enhancing anti-tumor responses have resulted in a new field of research known as FUS-induced/assisted cancer immunotherapy. In this work, we provide a comprehensive overview of this new research field by introducing the basics of focused ultrasound and cancer immunotherapy and providing the state-of-the-art applications of FUS in cancer immunotherapy: the mechanisms and preclinical and clinical studies. This review aims to offer the scientific community a reliable reference to the exciting field of FUS-induced/assisted cancer immunotherapy, hoping to foster the further development of related technology and expand its medical applications.

Immunotherapy in gastrointestinal cancers: current strategies and future directions - a literature review

Introduction

The National Cancer Institute defines the disease of "cancer" as a group of disorders in which aberrant cells proliferate uncontrollably and have the potential to infiltrate neighboring tissues. It is well established that cancer remains a significant etiology contributing to worldwide mortality. Gastrointestinal (GI) neoplasms are a type of cancer that affects the digestive system and adds to the total cancer burden. Conventionally, several therapies have been employed, such as radiation and chemotherapy; nevertheless, their adverse effects have prompted the need for an improved therapeutic alternative. Immunotherapy thus became a notable medium of treatment for several malignancies, including tumors of the GI tract.

Aim

This comprehensive review seeks to provide insight on future directions and prospective therapies under development, as well as information regarding the present strategies utilized to mitigate one of the primary forms of cancer, GI cancer.

Methods

A detailed analysis of the existing literature on GI cancers has been conducted. Several databases were employed to gather this information, mainly PubMed/MEDLINE. Different aspects of the disease were considered when searching the databases to provide a comprehensive review of the current and future strategies being incorporated to mitigate the negative consequences of this disease.

Results

Many strategies are being used currently, and some are still under development. These comprise the usage of immune checkpoint inhibitors (ICIs), cytokine therapy, cancer vaccines, oncolytic viruses, and adoptive cell therapy. For instance, various monoclonal antibodies have been developed to inhibit the immunomodulatory effects of programmed death-1 and programmed death-1 ligand. There are also results of several clinical trials showing significant benefits and many changes are introduced to make the best of these strategies and minimize the challenges to group sizes. These challenges include overcoming the tumor's immunosuppressive environment, finding suitable predictive biomarkers, and reducing the adverse effects. Additionally, several novel immunotherapeutic approaches, such as chimeric antigen receptor T-cell (CAR-T) therapy, are being studied. In 2017, the US FDA approved the use of two CAR-T therapies, which marks a major milestone following extensive research and clinical trials. New approaches such as toll-like receptor-directed and helminth-based immunotherapies are being developed for the treatment of GI cancers as well. These therapies, along with targeted treatments, represent the future of immunotherapy in GI cancers.

Conclusion

Immunotherapy plays a significant role in the different types of GI cancers. However, optimizing these treatments will require overcoming barriers such as immune resistance, minimizing side effects, and improving the selection of patients through biomarkers. Continued research into these novel therapies and the mechanisms of immune modulation will be key to maximizing the therapeutic benefits of immunotherapy in the future.

A bibliometric analysis of oncolytic virotherapy combined with immunotherapy

Oncolytic virotherapy in combination with immunotherapy has demonstrated significant survival benefits in some types of cancer. Here, we summarized the development, research hotpots and potential trends of the combination therapy using visual bibliometric analysis. A total of 712 articles were retrieved on June 21, 2023. The USA was the top contributors of any country (325, 45.65%), and the Rluk Research Libraries UK ranked first (43, 6.03%) of any institutions. The Journal for ImmunoTherapy of Cancer was with the largest publications (60, 8.43%). 'Tumor microenvironment' and 'delivery' were citation keywords with the strongest ongoing bursts. Research fronts in the future may focus on the methods of virus delivery and tumor microenvironment modulation. Futhermore, the most extensively studied cancer were melanoma, glioma and hepatocellular carcinoma.

Human Melanoma and Glioblastoma Cells Express Cathepsins Supporting Reovirus Moscow Strain Infection

This study evaluates the oncolytic potential of the Moscow strain of reovirus against human metastatic melanoma and glioblastoma cells. The Moscow strain effectively infects and replicates within human melanoma cell lines and primary glioblastoma cells, while sparing non-malignant human cells. Infection leads to the selective destruction of neoplastic cells, mediated by functional viral replication. A positive correlation was identified between viral RNA accumulation and tumor cell death, with no replication observed in non-malignant cells. This study highlights the critical roles of cathepsins B, L, and S as mediators of the oncolytic process. The pharmacological inhibition of these enzymes significantly attenuated reovirus-induced cytotoxicity in melanoma and glioblastoma cells. Conversely, PKR production analysis revealed minimal activation in reovirus-infected tumor cells, suggesting that the hyperactivation of the RAS-signaling pathway and subsequent PKR inhibition do not directly contribute to the selective efficacy of reovirus. Moreover, infected tumor cells exhibited features of both apoptotic and non-apoptotic death, emphasizing the intricate mechanisms of reovirus-mediated oncolysis. These findings underscore the therapeutic promise of the Moscow strain of reovirus as a selective and potent oncolytic agent for targeting melanoma and glioblastoma cells.

Safety of talimogene laherparepvec: a real-world retrospective pharmacovigilance study based on FDA Adverse Event Reporting System (FAERS)

BACKGROUND

Oncolytic virus therapy is a rapidly evolving emerging approach for the medical management of cancer. Talimogene laherparepvec (T-VEC) is the first and only Food and Drug Administration (FDA)-approved oncolytic virus therapy. Considering that exactly how T-VEC works is not known, there is a strong need for a comprehensive pharmacovigilance study to identify safety signals of potential risks with T-VEC.

OBJECTIVE

The objective of this study was to assess the risk of adverse events (AEs) related to T-VEC.

METHODS

We implemented a pharmacovigilance study utilizing individual case safety reports (ICSRs) reported to the FDA Adverse Event Reporting System (FAERS) database dated from 2004 quarter 1 to 2023 quarter 3. In this study, we used two algorithms, reporting odds ratio (ROR) and information component (IC), to assess the risk of AEs related to T-VEC.

RESULTS

A total of 1138 ICSRs of patients who received the T-VEC and reported to the FDA dated from 2004 quarter 1 to 2023 quarter 3 were available. A total of seven system organ classes (SOCs) demonstrated statistically significant signals, i.e. General disorders and administration site conditions, Injury, poisoning and procedural complication, Infections and infestations, Neoplasms benign, malignant and unspecified, Skin and subcutaneous tissue disorders, Hepatobiliary disorders, and Endocrine disorders. From the preferred term level perspective, the most reported AEs in T-VEC-treated patients were pyrexia, illness, influenza, influenza-like illness, and chills. Unexpected significant AEs were detected, such as sepsis, encephalitis, syncope, and lymphadenopathy.

CONCLUSIONS

Most AEs in T-VEC-treated patients have been previously mentioned in the prescriptive information or documented in other clinical trials. But safety signals were also be detected in 4 unexpected AEs (sepsis, encephalitis, syncope, and lymphadenopathy). Further clinical trials need to be undertaken to facilitate a more comprehensive comprehension of the safety profile of T-VEC.

The Small GTPase Ran Increases Sensitivity of Ovarian Cancer Cells to Oncolytic Vesicular Stomatitis Virus

Background/Objectives: Ovarian cancer is the deadliest gynecologic cancer, and with the majority of patients dying within the first five years of diagnosis, new therapeutic options are required. The small guanosine triphosphatase (GTPase) Ras-related nuclear protein (Ran) has been reported to be highly expressed in high-grade serous ovarian cancers (HGSOCs) and associated with poor outcomes. Blocking Ran function or preventing its expression were shown to be promising treatment strategies, however, there are currently no small molecule inhibitors available to specifically inhibit Ran function. Interestingly, a previous study suggested that the Vesicular stomatitis virus (VSV) could inhibit Ran activity. Given that VSV is an oncolytic virus (OV) and, therefore, has anti-cancer activity, we reasoned that oncolytic VSV (oVSV) might be particularly effective against ovarian cancer via Ran inhibition. Methods: We evaluated the sensitivity of patient-derived ovarian cancer cell lines to oVSV, as well as the impact of oVSV on Ran and vice versa, using overexpression systems, small interfering RNAs (siRNAs), and drug inhibition. Results: In this study, we evaluated the interplay between oVSV and Ran and found that, although oVSV does not consistently block Ran, increased Ran activation allows for better oVSV replication and tumor cell killing. Conclusions: Our study reveals a positive impact of Ran on oVSV sensitivity. Given the high expression of Ran in HGSOCs, which are particularly aggressive ovarian cancers, our data suggest that oVSV could be effective against the deadliest form of the disease.

The Potential of Oncolytic Virotherapy in the Treatment of Head and Neck Cancer: A Comprehensive Review

Head and neck cancer (HNC) represents a challenging oncological entity with significant morbidity and mortality rates. Despite advances in conventional therapies, including surgery, chemotherapy, and radiation therapy, the overall survival rates for advanced HNC remain suboptimal. In recent years, the emerging field of oncolytic virotherapy has gained attention as a promising therapeutic approach for various malignancies, including HNC. This review provides a comprehensive overview of the current understanding of oncolytic viruses (Ovs) in the context of HNC treatment, including their mechanisms of action, preclinical and clinical studies, challenges, and future directions. Future oncolytic virotherapy focuses on improving delivery and specificity through nanoparticle carriers and genetic modifications to enhance tumor targeting and immune response. Combining different OVs and integrating them with immunotherapies, such as checkpoint inhibitors, could overcome tumor resistance and improve outcomes. Personalized approaches and rigorous clinical trials are key to ensuring the safety and effectiveness of virotherapy in treating HNC.

Breaking Barriers: Animal viruses as oncolytic and immunotherapeutic agents for human cancers

Oncolytic viruses, defined as viruses capable of lysing cancer cells, emerged as a groundbreaking class of therapeutic entities poised to revolutionize cancer treatment. Their mode of action encompasses both direct tumor cell lysis and the indirect enhancement of anti-tumor immune responses. Notably, four leading contenders in this domain, Rigvir® in Latvia, T-VEC in the United States, H101 in China and Teserpaturev (DELYTACT®) in Japan, have earned approval for treating metastatic melanoma (Rigvir and T-VEC), nasopharyngeal carcinoma and malignant glioma, respectively. Despite these notable advancements, the integration of oncolytic viruses into cancer therapy encounters several challenges. Foremost among these hurdles is the considerable variability observed in clinical responses to oncolytic virus interventions. Moreover, the adaptive immune system may inadvertently target the oncolytic viruses themselves, diverting immune resources away from tumor antigens and undermining therapeutic efficacy. Another significant limitation arises from the presence of preexisting immunity against oncolytic viruses in certain patient populations, hampering treatment outcomes. To circumvent this obstacle, researchers are investigating the utilization of animal viruses, for which humans lack preexisting immunity, as a compelling alternative to human-derived counterparts. In our comprehensive review, we delve into the intricate nuances of oncolytic virotherapy, elucidating the multifaceted mechanisms through which these viruses exert their anti-cancer effects. Furthermore, we provide a thorough examination of animal-derived oncolytic viruses, highlighting their respective strengths and limitations. Lastly, we explore the promising potential of leveraging animal viruses as potent oncolytic agents, offering new avenues for enhancing the efficacy and reach of human cancer therapeutics.

Effects of virus-induced immunogenic cues on oncolytic virotherapy

Oncolytic virotherapy is a promising form of cancer treatment that uses viruses to infect and kill cancer cells. In addition to their direct effects on cancer cells, the viruses stimulate various immune responses partly directed against the tumour. Efforts are made to genetically engineer oncolytic viruses to enhance their immunogenic potential. However, the interplay between tumour growth, viral infection, and immune responses is complex and not fully understood, leading to variable and sometimes counterintuitive therapeutic outcomes. Here, we employ a spatio-temporal model to shed more light on this interplay. We investigate systematically how the properties of virus-induced immunogenic signals (their half-life, rate of spread, and potential to promote T-cell-mediated cytotoxicity) affect the therapeutic outcome. Our simulations reveal that strong immunogenic signals, combined with faster diffusion rates, improve the spread of immune activation, leading to better tumour eradication. However, replicate simulations suggest that the outcome of virotherapy is more stochastic than generally appreciated. Our model shows that virus-induced immune responses can interfere with virotherapy, by targeting virus-infected cancer cells and/or by impeding viral spread. In the presence of immune responses, the mode of virus introduction is important, with systemic viral delivery throughout the tumour yielding the most favourable outcomes. The timing of virus introduction also plays a critical role; depending on the efficacy of the immune response, a later start of virotherapy can be advantageous. Overall, our results emphasise that the rational design of oncolytic viruses requires optimising virus-induced immunogenic signals and strategies that balance viral spread with immune activity for improved therapeutic success.

Development and Characterization of an Oncolytic Human Adenovirus-Based Vector Co-Expressing the Adenovirus Death Protein and p14 Fusion-Associated Small Transmembrane Fusogenic Protein

Human adenovirus (HAdV)-based oncolytic vectors, which are designed to preferentially replicate in and kill cancer cells, have shown modest efficacy in human clinical trials in part due to poor viral distribution throughout the tumor mass. Previously, we showed that expression of the p14 fusion-associated small transmembrane (FAST) fusogenic protein could enhance oncolytic HAdV efficacy and reduce tumor growth rate in a human xenograft mouse model of cancer. We now explore whether co-expression of the adenovirus death protein (ADP) with p14 FAST protein could synergize to further enhance oncolytic vector efficacy. ADP is naturally encoded within the early region 3 (E3) of HAdV, a region which is frequently removed from HAdV-based vectors, and functions to enhance cell lysis and progeny release. We evaluated a variety of approaches to achieve optimal expression of the two proteins, the most efficient method being insertion of an expression cassette within the E3 deletion, consisting of the coding sequences for p14 FAST protein and ADP separated by a self-cleaving peptide derived from the porcine teschovirus-1 (P2A). However, the quantities of p14 FAST protein and ADP produced from this vector were reduced approximately 10-fold compared to a similar vector-expressing only p14 FAST protein and wildtype HAdV, respectively. Compared to our original oncolytic vector-expressing p14 FAST protein alone, reduced expression of p14 FAST protein and ADP from the P2A construct reduced cell-cell fusion, vector spread, and cell-killing activity in human A549 adenocarcinoma cells in culture. These studies show that a self-cleaving peptide can be used to express two different transgenes in an armed oncolytic HAdV vector, but also highlight the challenges in maintaining adequate transgene expression when modifying vector design.

High throughput screen identifies lysosomal acid phosphatase 2 (ACP2) to regulate IFN-1 responses to potentiate oncolytic VSV∆51 activity

Strategies in genetic and pharmacological modulation of innate immunity to enhance oncolytic virotherapy (OV) efficacy are being explored. We have recently characterized the ability for vanadium-based compounds, a class of pan-phosphatase (PP) inhibitors, to potentiate OVs. We next sought to identify PPs that could be targeted to enhance OVs, akin to vanadium. By conducting a high-throughput screen of a library of silencing RNA (siRNA) targeting human PPs, we uncovered several PPs that robustly enhanced infectivity and oncolysis of the oncolytic vesicular stomatitis virus (VSV∆51). Knockdown of our top validated hit, lysosomal acid phosphatase 2 (ACP2), increased VSV∆51 viral titers by over 20-fold. In silico analysis by RNA sequencing revealed ACP2 to regulate antiviral type I interferon (IFN-1) signaling pathways, similar to vanadium. To further exploit this mechanism for therapeutic gain, we encoded a short-hairpin RNA (shRNA) against ACP2 into oncolytic vesicular stomatitis virus (VSV∆51) under a miR-30 promoter. This bioengineered OV demonstrated expression of the miR-30 promoter, knockdown of ACP2, repression and ultimately, showed markedly enhanced viral VSV∆51 particle production compared to its non-targeting control counterpart. Altogether, this study identifies IFN-1 regulating PP targets, namely ACP2, that may prove instrumental in increasing the therapeutic efficacy of OVs.

VSV∆M51 drives CD8+ T cell-mediated tumour regression through infection of both cancer and non-cancer cells

Oncolytic viruses (OV) are designed to selectively infect and kill cancer cells, while simultaneously eliciting antitumour immunity. The mechanism is expected to originate from infected cancer cells. However, recent reports of tumour regression unaccompanied by cancer cell infection suggest a more complex mechanism of action. Here, we engineered vesicular stomatitis virus (VSV)ΔM51-sensitive and VSVΔM51-resistant tumour lines to elucidate the role of OV-infected cancer and non-cancer cells. We found that, while cancer cell infections elicit oncolysis and antitumour immunity as expected, infection of non-cancer cells alone can also contribute to tumour regression. This effect is partly attributed to the systemic production of cytokines that promote dendritic cell (DC) activation, migration and antigen cross-presentation, leading to magnified antitumour CD8+ T cell activation and tumour regression. Such OV-induced antitumour immunity is complementary to PD-1 blockade. Overall, our results reveal mechanistic insights into OV-induced antitumour immunity that can be leveraged to improve OV-based therapeutics.

Comparison of differences in immune cells and immune microenvironment among different kinds of oncolytic virus treatments

Oncolytic viruses are either naturally occurring or genetically engineered viruses that can activate immune cells and selectively replicate in and destroy cancer cells without damaging healthy tissues. Oncolytic virus therapy (OVT) represents an emerging treatment approach for cancer. In this review, we outline the properties of oncolytic viruses and then offer an overview of the immune cells and tumor microenvironment (TME) across various OVTs. A thorough understanding of the immunological mechanisms involved in OVTs could lead to the identification of novel and more effective therapeutic targets for cancer treatment.

An in silico approach uncovering the competency of oncolytic human adenovirus 52 for targeted breast cancer virotherapy

Breast cancer remains a major health threat throughout the world specifically in women above 30 years of age however, it is rarely known to affect men as well. It is characterized by the abnormal division of cells in the breast tissue resulting in the development of breast malignancies. Various risk factors contributing to breast cancer include age, family history, genetic mutations (chiefly in BRCA1 and BRCA2 genes) along with hormonal imbalances (oestrogen, progesterone, HER2). Early detection which can be obtained through frequent rounds of self-examination, mammographic scanning, and clinical assessment plays a crucial role in the prevention of the disease. In addition, appropriate diagnosis assists in better therapeutic responses. This study highlights the considerable health risks associated with the conventional treatment procedures which arise and increased demand of advanced, secure, and risk-free treatment alternatives. Oncolytic viruses are potentially apparent for the aim of improving cancer therapeutics with reduced side effects. These viruses act as the fundamental therapeutic agent themselves that selectively target and kill malignant cells without harm to healthy tissues. The key objective of the research is to provide evidence that Human Adenovirus 52 is a potent oncolytic virus and to highlight its capacity to target and eliminate cancer cells with precision while causing the least amount of harm to healthy tissues. Validating the in-silico method entails evaluating the precision and dependability of the computational modelling by contrasting the in-silico predictions with the findings from the experiments rank as the secondary objective. The workflow of this research utilized in-silico computational drug designing approaches including retrieval of tertiary structures of both the target Breast Cancer Type 1 Susceptibility Protein (BRCA1) and the viral Human Adenovirus 52 protein, their validation generating Ramachandran Plots determining favoured amino acid residue angles and prediction of their active residues. Furthermore, the study focused on the molecular dynamics docking of proteins, interpretation of molecular interactions between the docked complex, as well as the assessment of the molecular dynamic simulations (MD) in addition to their MMGBSA binding energy calculations. A successful docking between BRCA1 and Adenovirus protein provided a significant score of 329.2 +/- 24.3, furthermore, MD simulations showed a high RMSD peak at 2.8 Å, RMSF were maximum at 3.5 Å with highest protein-protein interaction, the radius of gyration was stable throughout the simulation representing elastic stability along with a high energy interaction value of - 7882 kCal/mol. Moreover, the MMGBSA calculation results showed a notable release of binding free energy of - 68.96 kCal/mol demonstrating effective bond formation between the docked complex. These findings propose the effectiveness of Human Adenovirus 52 to treat cancer. The selected oncolytic Human Adenovirus 52 is a potential candidate for the target specific treatment of breast cancer through virotherapy. This computer-aided drug discovery presents significant potential in targeting cancer cells and would assist in the development of potent drug reagents for the cancer therapy.

Virus nanotechnology for intratumoural immunotherapy

Viruses can be designed to be tools and carrier vehicles for intratumoural immunotherapy. Their nanometre-scale size and shape allow for functionalization with or encapsulation of medical cargoes and tissue-specific ligands. Importantly, immunotherapies may particularly benefit from the inherent immunomodulatory properties of viruses. For example, mammalian viruses have already been tested for oncolytic virotherapy, and bacteriophages and plant viruses can be engineered for immunotherapeutic treatment approaches. In this Review, we discuss how viruses - including oncolytic viruses, immunomodulatory plant viruses and bacteriophages - and virus-like particles can be designed for intratumoural immunotherapy to elicit anti-tumour immunity and induce systemic anti-tumour responses at distant non-injected sites. We further highlight the engineering of viruses and virus-like particles as drug-delivery systems, and outline key translational challenges and clinical opportunities.

The implications of oncolytic viruses targeting fibroblasts in enhancing the antitumoural immune response

Oncolytic viruses (OVs) are an emerging immunotherapy platform that selectively target tumour cells, inducing immunogenic cell death. This reverses the 'immune-desert' phenotype of tumours, enhancing antitumour immunity. However, oncolytic virotherapy has shown limited efficacy in solid tumours due to the presence of protumoural, immunosuppressive cancer-associated fibroblasts (CAFs). Recent studies have explored OVs that specifically target CAFs to enhance antitumoural immune responses, with promising results. Nevertheless, detailed interrogation of the experimental design of these studies casts doubt on their potential for successful clinical translation. Most studies targeted CAFs non-specifically, failing to acknowledge CAF heterogeneity, with antitumoural CAFs also present. Thus, use of transcriptomics is advisable to provide more focused targeting, limiting potential off-target toxicity. Furthermore, experiments to date have largely been conducted in murine models that do not faithfully recapitulate tumour microenvironments, potentially biasing the efficacy observed. Future work should make use of humanised patient-derived xenograft murine models for animal studies, after which primary human tumour biopsies should be utilised to more closely represent the patient population for maximal translation relevance. Additionally, approaches to enhance the antitumoural immune responses of this therapy should be prioritised, with the ultimate aim of achieving complete remission, which has not yet been observed pre-clinically.

Oncolytic viruses: a potential breakthrough immunotherapy for multiple myeloma patients

Oncolytic virotherapy represents an innovative and promising approach for the treatment of cancer, including multiple myeloma (MM), a currently incurable plasma cell (PC) neoplasm. Despite the advances that new therapies, particularly immunotherapy, have been made, relapses still occur in MM patients, highlighting the medical need for new treatment options. Oncolytic viruses (OVs) preferentially infect and destroy cancer cells, exerting a direct and/or indirect cytopathic effect, combined with a modulation of the tumor microenvironment leading to an activation of the immune system. Both naturally occurring and genetically modified viruses have demonstrated significant preclinical effects against MM cells. Currently, the OVs genetically modified measles virus strains, reovirus, and vesicular stomatitis virus are employed in clinical trials for MM. Nevertheless, significant challenges remain, including the efficiency of the virus delivery to the tumor, overcoming antiviral immune responses, and the specificity of the virus for MM cells. Different strategies are being explored to optimize OV therapy, including combining it with standard treatments and targeted therapies to enhance efficacy. This review will provide a comprehensive analysis of the mechanism of action of the different OVs, and preclinical and clinical evidence, focusing on the role of oncolytic virotherapy as a new possible immunotherapeutic approach also in combination with the current therapeutic armamentarium and underlying the future directions in the context of MM treatments.

Practical immunomodulatory landscape of glioblastoma multiforme (GBM) therapy

Glioblastoma multiforme (GBM) is the most common harmful high-grade brain tumor with high mortality and low survival rate. Importantly, besides routine diagnostic and therapeutic methods, modern and useful practical techniques are urgently needed for this serious malignancy. Correspondingly, the translational medicine focusing on genetic and epigenetic profiles of glioblastoma, as well as the immune framework and brain microenvironment, based on these challenging findings, indicates that key clinical interventions include immunotherapy, such as immunoassay, oncolytic viral therapy, and chimeric antigen receptor T (CAR T) cell therapy, which are of great importance in both diagnosis and therapy. Relatively, vaccine therapy reflects the untapped confidence to enhance GBM outcomes. Ongoing advances in immunotherapy, which utilizes different methods to regenerate or modify the resistant body for cancer therapy, have revealed serious results with many different problems and difficulties for patients. Safe checkpoint inhibitors, adoptive cellular treatment, cellular and peptide antibodies, and other innovations give researchers an endless cluster of instruments to plan profoundly in personalized medicine and the potential for combination techniques. In this way, antibodies that block immune checkpoints, particularly those that target the program death 1 (PD-1)/PD-1 (PD-L1) ligand pathway, have improved prognosis in a wide range of diseases. However, its use in combination with chemotherapy, radiation therapy, or monotherapy is ineffective in treating GBM. The purpose of this review is to provide an up-to-date overview of the translational elements concentrating on the immunotherapeutic field of GBM alongside describing the molecular mechanism involved in GBM and related signaling pathways, presenting both historical perspectives and future directions underlying basic and clinical practice.

Intratumoral microbiota: an emerging force in diagnosing and treating hepatocellular carcinoma

Hepatocellular carcinoma (HCC) ranks among the most prevalent types of cancer in the world and its incidence and mortality are increasing year by year, frequently diagnosed at an advanced stage. Traditional treatments such as surgery, chemotherapy, and radiotherapy have limited efficacy, so new diagnostic and treatment strategies are urgently needed. Recent research has discovered that intratumoral microbiota significantly influences the development, progression, and metastasis of HCC by modulating inflammation, immune responses, and cellular signaling pathways. Intratumoral microbiota contributes to the pathologic process of HCC by influencing the tumor microenvironment and altering the function of immune system. This article reviews the mechanism of intratumoral microbiota in HCC and anticipates the future possibilities of intratumoral microbiota-based therapeutic strategies for HCC management. This emerging field provides fresh insights into early diagnosis and personalized approaches for HCC while holding substantial clinical application potential to improve patient outcomes and tailor interventions to individual tumor profiles.

Oncolytic vaccinia virus harboring aphrocallistes vastus lectin exerts anti-tumor effects by directly oncolysis and inducing immune response through enhancing ROS in human ovarian cancer

Aphrocallistes vastus lectin (AVL) is a Ca2+ dependent C-type lectin produced by sponges. Previous studies have demonstrated that oncolytic vaccinia virus harboring AVL (oncoVV-AVL) effectively triggers cell death in various tumors. However, the effects of oncoVV-AVL on human ovarian cancer (OV) remain unknown. This study aims to investigate the mechanism-of-action of oncoVV-AVL in human OV cell lines and in tumor-bearing nude mice. We found that oncoVV-AVL could directly induce apoptosis and autophagy in ovarian cancer cells. Additionally, our results showed that oncoVV-AVL increased the serum levels of mouse IFN-γ (mIFN-γ), leading to the activation of M1-polarized macrophages. Conversely, NADPH, a reducing agent by providing reducing equivalents, reduced the production of mIFN-γ, and suppressed M1-polarization of macrophage. Based on these findings, we propose that oncoVV-AVL not only contributes to direct cytolysis, but also enhances host immune response by promoting ROS levels.

Thymosin α1 reverses oncolytic adenovirus-induced M2 polarization of macrophages to improve antitumor immunity and therapeutic efficacy

Although oncolytic adenoviruses are widely studied for their direct oncolytic activity and immunomodulatory role in cancer immunotherapy, the immunosuppressive feedback loop induced by oncolytic adenoviruses remains to be studied. Here, we demonstrate that type V adenovirus (ADV) induces the polarization of tumor-associated macrophages (TAMs) to the M2 phenotype and increases the infiltration of regulatory T cells (Tregs) in the tumor microenvironment (TME). By selectively compensating for these deficiencies, thymosin alpha 1 (Tα1) reprograms "M2-like" TAMs toward an antitumoral phenotype, thereby reprogramming the TME into a state more beneficial for antitumor immunity. Moreover, ADVTα1 is constructed by harnessing the merits of all the components for the aforementioned combinatorial therapy. Both exogenously supplied and adenovirus-produced Tα1 orchestrate TAM reprogramming and enhance the antitumor efficacy of ADV via CD8+ T cells, showing promising prospects for clinical translation. Our findings provide inspiration for improving oncolytic adenovirus combination therapy and designing oncolytic engineered adenoviruses.

Nanoengineering-armed oncolytic viruses drive antitumor response: progress and challenges

Oncolytic viruses (OVs) have emerged as a powerful tool in cancer therapy. Characterized with the unique abilities to selectively target and lyse tumor cells, OVs can expedite the induction of cell death, thereby facilitating effective tumor eradication. Nanoengineering-derived OVs overcome traditional OV therapy limitations by enhancing the stability of viral circulation, and tumor targeting, promising improved clinical safety and efficacy and so on. This review provides a comprehensive analysis of the multifaceted mechanisms through which engineered OVs can suppress tumor progression. It initiates with a concise delineation on the fundamental attributes of existing OVs, followed by the exploration of their mechanisms of the antitumor response. Amid rapid advancements in nanomedicine, this review presents an extensive overview of the latest developments in the synergy between nanomaterials, nanotechnologies, and OVs, highlighting the unique characteristics and properties of the nanomaterials employed and their potential to spur innovation in novel virus design. Additionally, it delves into the current challenges in this emerging field and proposes strategies to overcome these obstacles, aiming to spur innovation in the design and application of next-generation OVs.

A novel vesicular stomatitis virus armed with IL-2 mimic for oncolytic therapy

Oncolytic virus (OV) is increasingly being recognized as a novel vector in cancer immunotherapy. Increasing evidence suggests that OV has the ability to change the immune status of tumor microenvironment, so called transformation of 'cold' tumors into 'hot' tumors. The improved anti-tumor immunity can be induced by OV and further enhanced through the combination of various immunomodulators. The Neo-2/15 is a newly de novo synthesized cytokine that functions as both IL-2 and IL-15. However, it specifically lacks the binding site of IL-2 receptor α subunit (CD25), therefore unable to induce the Treg proliferation. In present study, a recombinant vesicular stomatitis virus expressing the Neo-2/15 (VSVM51R-Neo-2/15) was generated. Intratumoral delivery of VSVM51R-Neo-2/15 efficiently inhibited tumor growth in mice without causing the IL-2-related toxicity previously observed in clinic. Moreover, treatment with VSVM51R-Neo-2/15 increased the number of activated CD8+ T cells but not Treg cells in tumors. More tumor-bearing mice were survival with VSVM51R-Neo-2/15 treatment, and the surviving mice displayed enhanced protection against tumor cell rechallenge due to the induced anti-tumor immunity. In addition, combination therapy of OV and anti-PD-L1 immune checkpoint inhibitors further enhanced the anti-tumor immune response. These findings suggest that our novel VSVM51R-Neo-2/15 can effectively inhibit the tumor growth and enhance the sensitivity to immune checkpoint inhibitors, providing promising attempts for further clinical trials.

Oncolytic virus and tumor-associated macrophage interactions in cancer immunotherapy

Oncolytic viruses (OV) are a promising strategy in cancer immunotherapy. Their capacity to promote anti-tumoral immunity locally raises hope that cancers unresponsive to current immunotherapy approaches could be tackled more efficiently. In this context, tumor-associated macrophages (TAM) must be considered because of their pivotal role in cancer immunity. Even though TAM tend to inhibit anti-tumoral responses, their ability to secrete pro-inflammatory cytokines and phagocytose cancer cells can be harnessed to promote therapeutic cancer immunity. OVs have the potential to promote TAM pro-inflammatory functions that favor anti-tumoral immunity. But in parallel, TAM pro-inflammatory functions induce OV clearance in the tumor, thereby limiting OV efficacy and highlighting that the interaction between OV and TAM is a double edge sword. Moreover, engineered OVs were recently developed to modulate specific TAM functions such as phagocytic activity. The potential of circulating monocytes to deliver OV into the tumor after intravenous administration is also emerging. In this review, we will present the interaction between OV and TAM, the potential of engineered OV to modulate specific TAM functions, and the promising role of circulating monocytes in OV delivery to the tumor.

Advances in Immunomodulatory Mesoporous Silica Nanoparticles for Inflammatory and Cancer Therapies

In recent decades, immunotherapy has been considered a promising treatment approach. The modulatable enhancement or attenuation of the body's immune response can effectively suppress tumors. However, challenges persist in clinical applications due to the lack of precision in antigen presentation to immune cells, immune escape mechanisms, and immunotherapy-mediated side effects. As a potential delivery system for drugs and immunomodulators, mesoporous silica has attracted extensive attention recently. Mesoporous silica nanoparticles (MSNs) possess high porosity, a large specific surface area, excellent biocompatibility, and facile surface modifiability, making them suitable as multifunctional carriers in immunotherapy. This article summarizes the latest advancements in the application of MSNs as carriers in cancer immunotherapy, aiming to stimulate further exploration of the immunomodulatory mechanisms and the development of immunotherapeutics based on MSNs.

An Unconventional Case Study of Neoadjuvant Oncolytic Virotherapy for Recurrent Breast Cancer

Intratumoural oncolytic virotherapy may have promise as a means to debulk and downstage inoperable tumours in preparation for successful surgery. Here, we describe the unique case of a 50-year-old self-experimenting female virologist with locally recurrent muscle-invasive breast cancer who was able to proceed to simple, non-invasive tumour resection after receiving multiple intratumoural injections of research-grade virus preparations, which first included an Edmonston-Zagreb measles vaccine strain (MeV) and then a vesicular stomatitis virus Indiana strain (VSV), both prepared in her own laboratory. The intratumoural virus therapy was well tolerated. Frequent imaging studies and regular clinical observations documenting size, consistency and mobility of the injected tumour demonstrate that both the MeV- and VSV-containing parts of the protocol contributed to the overall favourable response. Two months after the start of the virus injections, the shrunken tumour was no longer invading the skin or underlying muscle and was surgically excised. The excised tumour showed strong lymphocytic infiltration, with an increase in CD20-positive B cells, CD8-positive T cells and macrophages. PD-L1 expression was detected in contrast to the baseline PD-L1-negative phenotype. The patient completed one-year trastuzumab adjuvant therapy and remains well and recurrence-free 45 months post-surgery. Although an isolated case, it encourages consideration of oncolytic virotherapy as a neoadjuvant treatment modality.

Synergistic cytotoxicity of olive leaf extract-loaded lipid nanocarriers combined with Newcastle disease virus against cervical cancer cells

Despite recent medical progress, cervical cancer remains a major global health concern for women. Current standard treatments have limitations such as non-specific toxicity that necessitate development of safer and more effective therapeutic strategies. This research evaluated the combinatorial effects of olive leaf extract (OLE), rich in anti-cancer polyphenols, and the oncolytic Newcastle disease virus (NDV) against human cervical cancer cells. OLE was efficiently encapsulated (>94% loading) within MF59 lipid nanoparticles and nanostructured lipid carriers (NLCs; contains Precirol as NLC-P, contains Lecithin as NLC-L) to enhance stability, bioavailability, and targeted delivery. Physicochemical analysis confirmed successful encapsulation of OLE within nanoparticles smaller than 150 nm. In vitro cytotoxicity assays demonstrated significantly higher toxicity of the OLE-loaded nanoparticle formulations on HeLa cancer cells versus HDF normal cells (P<0.05). MF59 achieved the highest encapsulation efficiency, while NLC-P had the best drug release profile. NDV selectively infected and killed HeLa cells versus HDF cells. Notably, combining NDV with OLE-loaded nanoparticles led to significantly enhanced synergistic cytotoxicity against cancer cells (P<0.05), with NLC-P (OLE) and NDV producing the strongest effects. Apoptosis and cell cycle analyses confirmed the increased anti-cancer activity of the combinatorial treatment, which induced cell cycle arrest. This study provides evidence that co-delivery of OLE-loaded lipid nanoparticles and NDV potentiates anti-cancer activity against cervical cancer cells in vitro through a synergistic mechanism, warranting further development as a promising alternative cervical cancer therapy.

Recent advances in sialic acid-based active targeting chemoimmunotherapy promoting tumor shedding: a systematic review

Tumors have always been a major public health concern worldwide, and attempts to look for effective treatments have never ceased. Sialic acid is known to be a crucial element for tumor development and its receptors are highly expressed on tumor-associated immune cells, which perform significant roles in establishing the immunosuppressive tumor microenvironment and further boosting tumorigenesis, progression, and metastasis. Obviously, it is essential to consider sophisticated crosstalk between tumors, the immune system, and preparations, and understand the links between pharmaceutics and immunology. Sialic acid-based chemoimmunotherapy enables active targeting drug delivery via mediating the recognition between the sialic acid-modified nano-drug delivery system represented by liposomes and sialic acid-binding receptors on tumor-associated immune cells, which inhibit their activity and utilize their homing ability to deliver drugs. Such a "Trojan horse" strategy has remarkably improved the shortcomings of traditional passive targeting treatments, unexpectedly promoted tumor shedding, and persistently induced robust immunological memory, thus highlighting its prospective application potential for targeting various tumors. Herein, we review recent advances in sialic acid-based active targeting chemoimmunotherapy to promote tumor shedding, summarize the current viewpoints on the tumor shedding mechanism, especially the formation of durable immunological memory, and analyze the challenges and opportunities of this attractive approach.

Oncolytic Tanapoxvirus Variants Expressing mIL-2 and mCCL-2 Regress Human Pancreatic Cancer Xenografts in Nude Mice

Pancreatic ductal adenocarcinoma (PDAC) is the fifth leading cause of cancer-related death and presents the lowest 5-year survival rate of any form of cancer in the US. Only 20% of PDAC patients are suitable for surgical resection and adjuvant chemotherapy, which remains the only curative treatment. Chemotherapeutic and gene therapy treatments are associated with adverse effects and lack specificity/efficacy. In this study, we assess the oncolytic potential of immuno-oncolytic tanapoxvirus (TPV) recombinants expressing mouse monocyte chemoattractant protein (mMCP-1 or mCCL2) and mouse interleukin (mIL)-2 in human pancreatic BxPc-3 cells using immunocompromised and CD-3+ T-cell-reconstituted mice. Intratumoral treatment with TPV/∆66R/mCCL2 and TPV/∆66R/mIL-2 resulted in a regression in BxPc-3 xenograft volume compared to control in immunocompromised mice; mCCL-2 expressing TPV OV resulted in a significant difference from control at p < 0.05. Histological analysis of immunocompromised mice treated with TPV/∆66R/mCCL2 or TPV/∆66R/mIL-2 demonstrated multiple biomarkers indicative of increased severity of chronic, active inflammation compared to controls. In conclusion, TPV recombinants expressing mCCL2 and mIL-2 demonstrated a therapeutic effect via regression in BxPc-3 tumor xenografts. Considering the enhanced oncolytic potency of TPV recombinants demonstrated against PDAC in this study, further investigation as an alternative or combination treatment option for human PDAC may be warranted.

Parainfluenza Virus 5 V Protein Blocks Interferon Gamma-Mediated Upregulation of NK Cell Inhibitory Ligands and Improves NK Cell Killing of Neuroblastoma Cells

Natural killer (NK) cells can be effective immunotherapeutic anti-cancer agents due to their ability to selectively target and kill tumor cells. This activity is modulated by the interaction of NK cell receptors with inhibitory ligands on the surface of target cells. NK cell inhibitory ligands can be upregulated on tumor cell surfaces in response to interferon-gamma (IFN-γ), a cytokine which is produced by activated NK cells. We hypothesized that the resistance of tumor cells to NK cell killing could be overcome by expression of the parainfluenza virus 5 (PIV5) V protein, which has known roles in blocking IFN-γ signaling. This was tested with human PM21-NK cells produced through a previously developed particle-based method which yields superior NK cells for immunotherapeutic applications. Infection of human SK-N-SH neuroblastoma cells with PIV5 blocked IFN-γ-mediated upregulation of three NK cell inhibitory ligands and enhanced in vitro killing of these tumor cells by PM21-NK cells. SK-N-SH cells transduced to constitutively express the V protein alone were resistant to IFN-γ-mediated increases in cell surface expression of NK cell inhibitory ligands. Real-time in vitro cell viability assays demonstrated that V protein expression in SK-N-SH cells was sufficient to increase PM21-NK cell-mediated killing. Toward a potential therapeutic application, transient lentiviral delivery of the V gene also enhanced PM21-NK cell killing in vitro. Our results provide the foundation for novel therapeutic applications of V protein expression in combination with ex vivo NK cell therapy to effectively increase the killing of tumor cells.

Mechanism insights and therapeutic intervention of tumor metastasis: latest developments and perspectives

Metastasis remains a pivotal characteristic of cancer and is the primary contributor to cancer-associated mortality. Despite its significance, the mechanisms governing metastasis are not fully elucidated. Contemporary findings in the domain of cancer biology have shed light on the molecular aspects of this intricate process. Tumor cells undergoing invasion engage with other cellular entities and proteins en route to their destination. Insights into these engagements have enhanced our comprehension of the principles directing the movement and adaptability of metastatic cells. The tumor microenvironment plays a pivotal role in facilitating the invasion and proliferation of cancer cells by enabling tumor cells to navigate through stromal barriers. Such attributes are influenced by genetic and epigenetic changes occurring in the tumor cells and their surrounding milieu. A profound understanding of the metastatic process's biological mechanisms is indispensable for devising efficacious therapeutic strategies. This review delves into recent developments concerning metastasis-associated genes, important signaling pathways, tumor microenvironment, metabolic processes, peripheral immunity, and mechanical forces and cancer metastasis. In addition, we combine recent advances with a particular emphasis on the prospect of developing effective interventions including the most popular cancer immunotherapies and nanotechnology to combat metastasis. We have also identified the limitations of current research on tumor metastasis, encompassing drug resistance, restricted animal models, inadequate biomarkers and early detection methods, as well as heterogeneity among others. It is anticipated that this comprehensive review will significantly contribute to the advancement of cancer metastasis research.

Oncolytic adenoviral therapy plus pembrolizumab in BCG-unresponsive non-muscle-invasive bladder cancer: the phase 2 CORE-001 trial

Cretostimogene grenadenorepvec is a serotype-5 oncolytic adenovirus designed to selectively replicate in cancer cells with retinoblastoma pathway alterations, previously tested as monotherapy in bacillus Calmette-Guérin (BCG)-experienced non-muscle-invasive bladder cancer. In this phase 2 study, we assessed the potential synergistic efficacy between intravesical cretostimogene and systemic pembrolizumab in patients with BCG-unresponsive non-muscle-invasive bladder cancer with carcinoma in situ (CIS). Thirty-five patients were treated with intravesical cretostimogene with systemic pembrolizumab. Induction cretostimogene was administered weekly for 6 weeks followed by three weekly maintenance infusions at months 3, 6, 9, 12 and 18 in patients maintaining complete response (CR). Patients with persistent CIS/high-grade Ta at the 3-month assessment were eligible for re-induction. Pembrolizumab was administered for up to 24 months. The primary endpoint was CR at 12 months as assessed by cystoscopy, urine cytology, cross-sectional imaging and mandatory bladder mapping biopsies. Secondary endpoints included CR at any time, duration of response, progression-free survival and safety. The CR rate in the intention-to-treat population at 12 months was 57.1% (20 out of 35, 95% confidence interval (CI) 40.7-73.5%), meeting the primary endpoint. A total of 29 out of 35 patients (82.9%, 95% CI 70.4-95.3%) derived a CR at 3 months. With a median follow-up of 26.5 months, the median duration of response has not been reached (95% CI 15.7 to not reached). The CR rate at 24 months was 51.4% (18 out of 35) (95% CI 34.9-68.0%). No patient progressed to muscle-invasive bladder cancer in this trial. Adverse events attributed to cretostimogene were low grade, self-limiting and predominantly limited to bladder-related symptoms. A total of 5 out of 35 patients (14.3%) developed grade 3 treatment-related adverse effects. There was no evidence of overlapping or synergistic toxicities. Combination intravesical cretostimogene and systemic pembrolizumab demonstrated enduring efficacy. With a toxicity profile similar to its monotherapy components, this combination may shift the benefit-to-risk ratio for patients with BCG-unresponsive CIS. ClinicalTrials.gov Identifier: NCT04387461 .

Bacterial outer membrane vesicle nanorobot

Autonomous nanorobots represent an advanced tool for precision therapy to improve therapeutic efficacy. However, current nanorobotic designs primarily rely on inorganic materials with compromised biocompatibility and limited biological functions. Here, we introduce enzyme-powered bacterial outer membrane vesicle (OMV) nanorobots. The immobilized urease on the OMV membrane catalyzes the decomposition of bioavailable urea, generating effective propulsion for nanorobots. This OMV nanorobot preserves the unique features of OMVs, including intrinsic biocompatibility, immunogenicity, versatile surface bioengineering for desired biofunctionalities, capability of cargo loading and protection. We present OMV-based nanorobots designed for effective tumor therapy by leveraging the membrane properties of OMVs. These involve surface bioengineering of robotic body with cell-penetrating peptide for tumor targeting and penetration, which is further enhanced by active propulsion of nanorobots. Additionally, OMV nanorobots can effectively safeguard the loaded gene silencing tool, small interfering RNA (siRNA), from enzymatic degradation. Through systematic in vitro and in vivo studies using a rodent model, we demonstrate that these OMV nanorobots substantially enhanced siRNA delivery and immune stimulation, resulting in the utmost effectiveness in tumor suppression when juxtaposed with static groups, particularly evident in the orthotopic bladder tumor model. This OMV nanorobot opens an inspiring avenue to design advanced medical robots with expanded versatility and adaptability, broadening their operation scope in practical biomedical domains.