The emerging field of oncolytic virus-based cancer immunotherapy

AVL-armed oncolytic vaccinia virus promotes viral replication and boosts antitumor immunity via increasing ROS levels in pancreatic cancer

Pancreatic malignant neoplasm is an extremely deadly malignancy well known for its resistance to traditional therapeutic approaches. Enhanced treatments are imperative for individuals diagnosed with pancreatic cancer (PC). Recent investigations have shed light on the wide-ranging anticancer properties of genetic therapy facilitated by oncolytic vaccinia virus. To illuminate the precise impacts of Aphrocallistes vastus lectin-armed oncolytic vaccinia virus (oncoVV-AVL) on PC, AsPC-1 and PANC-1 cells underwent treatment with oncoVV-AVL. Our findings revealed that oncoVV-AVL possesses the capacity to heighten oncolytic effects on PC cells and incite the production of diverse cytokines like tumor necrosis factor-α, interleukin-6 (IL-6), IL-8, and interferon-I (IFN-I), without triggering antiviral responses. Additionally, oncoVV-AVL can significantly elevate the levels of ROS in PC cells, initiating an oxidative stress response that promotes viral replication, apoptosis, and autophagy. Moreover, in xenograft tumor models, oncoVV-AVL notably restrained PC growth, enhanced IFN-γ levels in the bloodstream, and reprogrammed macrophages. Our investigation indicates that oncoVV-AVL boosts the efficacy of antitumor actions against PC tumors by orchestrating reactive oxygen species-triggered viral replication, fostering M1 polarization, and reshaping the tumor microenvironment to transform cold PC tumors into hot ones. These findings imply that oncoVV-AVL could present a novel therapeutic approach for treating PC tumors.

Oncolytic vaccinia virus armed with 4-1BBL elicits potent and safe antitumor immunity and enhances the therapeutic efficiency of PD-1/PD-L1 blockade in a pancreatic cancer model

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with a poor prognosis. Mono-immunotherapy, such as blockade of the PD-1/PD-L1 pathway, for PDAC has proven to be less effective. The systemic exertion of 4-1BB signaling enhanced antitumor immunity accompanied by hepatotoxicity, which is an obstacle for its clinical application. Our study exploits an oncolytic virus armed with 4-1BBL (VV-ΔTK-4L) to locally express 4-1BBL in the tumor microenvironment (TME), thus avoiding hepatotoxicity. VV-ΔTK-4L prolonged the survival time of a pancreatic tumor mouse model and modified the immune status of the TME and spleen. In the TME, the quantities of CD45+ cells, NK1.1+ cells, CD11c+ DCs, CD3+T, CD4+T, and CD8+T cells increased. Compared to VV-ΔTK treatment, VV-ΔTK-4L further increases the number of CD8+T cells with effector phenotypes, and downregulates exhaustion-related molecules on CD8+T cells, and does not increase the proportion of Foxp3+T cells. Thus, the TME of pancreatic cancer was converted from "cold" to "hot" by VV-ΔTK-4L. Blockade of the PD-1/PD-L1 pathway combined with VV-ΔTK-4L further significantly improves the survival ratio of a tumor-bearing mouse model. This study provides a systemic therapeutic strategy and approach for PDAC immunotherapy.

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.

Universal CAR cell therapy: Challenges and expanding applications

Chimeric Antigen Receptor (CAR) T cell therapy has gained success in adoptive cell therapy for hematological malignancies. Although most CAR cell therapies in clinical trials or markets remain autologous, their acceptance has been limited due to issues like lengthy manufacturing, poor cell quality, and demanding cost. Consequently, "Off-the-shelf", universal CAR (UCAR) cell therapy has emerged. Current concerns with UCAR therapies revolve around side effects such as graft versus host disease (GVHD) and host versus graft response (HVGR). Preclinical research on UCAR cell therapies aims to enhance efficacy and minimize these side effects. Common approaches involve gene editing techniques to knock out T cell receptor (TCR), human leukocyte antigen (HLA), and CD52 expression to mitigate GVHD and HVGR risks. However, these methods carry drawbacks including potential genotoxicity of the edited cells. Most recently, novel editing techniques, such as epigenetic editing and RNA writer systems, have been developed to reduce the risk of GVHD and HVGR, allowing for multiplex editing at different sites. Additionally, incorporating more cell types into UCAR cell therapies, like T-cell subtypes (DNT, γδT, virus-specific T cells) and NK cells, can efficiently target tumors without triggering side effects. In addition, the limited efficacy of T cells and NK cells against solid tumors is being addressed through CAR-Macrophages. In summary, CAR cell therapy has evolved to accommodate multiple cell types while expanding applications to various diseases, including hematologic malignancies and solid tumors, which holds tremendous growth potential and is promised to improve the lives of more patients in the future.

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.

Multi-Enzyme Nanoparticles as Efficient Pyroptosis and Immunogenic Cell Death Inducers for Cancer Immunotherapy

Immunotherapy represents a widely employed modality in clinical oncology, leveraging the activation of the human immune system to target and eradicate cancer cells and tumor tissues via endogenous immune mechanisms. However, its efficacy remains constrained by inadequate immune responses within "cold" tumor microenvironment (TME). In this study, a multifunctional nanoscale pyroptosis inducer with cascade enzymatic activity (IMZF), comprising superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione oxidase (GSHOx), is dissociated within the acidic and glutathione-rich TME. The vigorous enzymatic activity not only generates oxygen (O2) to alleviate hypoxia and promote M2 to M1 macrophage polarization but also yields reactive oxygen species (ROS) and depletes glutathione (GSH) within the TME. Functioning as an immunogenic cell death (ICD) activator and pyroptosis inducer, IMZF synergistically triggers dendritic cell maturation and inflammatory lymphocyte infiltration via ICD-associated pyroptosis, thereby reversing immune suppression within the TMEs. Consequently, it exerts inhibitory effects on both primary and distal tumors. This cascade enzymatic platform-based pyroptosis inducer offers an intelligent strategy for effectively overcoming immune suppression within "cold" tumors, thereby providing a promising avenue for advanced immunotherapeutic interventions.

CAR-T and CAR-NK as cellular cancer immunotherapy for solid tumors

In the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach for combating cancers, demonstrating remarkable efficacy in relapsed/refractory hematological malignancies in both pediatric and adult patients. CAR-natural killer (CAR-NK) cell complements CAR-T cell therapy by offering several distinct advantages. CAR-NK cells do not require HLA compatibility and exhibit low safety concerns. Moreover, CAR-NK cells are conducive to "off-the-shelf" therapeutics, providing significant logistic advantages over CAR-T cells. Both CAR-T and CAR-NK cells have shown consistent and promising results in hematological malignancies. However, their efficacy against solid tumors remains limited due to various obstacles including limited tumor trafficking and infiltration, as well as an immuno-suppressive tumor microenvironment. In this review, we discuss the recent advances and current challenges of CAR-T and CAR-NK cell immunotherapies, with a specific focus on the obstacles to their application in solid tumors. We also analyze in depth the advantages and drawbacks of CAR-NK cells compared to CAR-T cells and highlight CAR-NK CAR optimization. Finally, we explore future perspectives of these adoptive immunotherapies, highlighting the increasing contribution of cutting-edge biotechnological tools in shaping the next generation of cellular immunotherapy.

An oncolytic HSV-1 vector induces a therapeutic adaptive immune response against glioblastoma

BACKGROUND

Glioblastoma (GBM) is the most frequent and aggressive brain tumor in adults with the lowest survival rates five years post-diagnosis. Oncolytic viruses (OVs) selectively target and damage cancer cells, and for this reason they are being investigated as new therapeutic tools also against GBM.

METHODS

An oncolytic herpes simplex virus type 1 (oHSV-1) with deletions in the γ34.5 neurovirulence gene and the US12 gene, expressing enhanced green fluorescent protein (EGFP-oHSV-1) as reporter gene was generated and tested for its capacity to infect and kill the murine GL261 glioblastoma (GBM) cell line. Syngeneic mice were orthotopically injected with GL261cells. Seven days post-implantation, EGFP-oHSV-1 was administered intratumorally. Twenty-one days after parental tumor challenge in the opposite brain hemisphere, mice were sacrified and their brains were analysed by immunohistochemistry to assess tumor presence and cell infiltrate.

RESULTS

oHSV-1 replicates and induces cell death of GL261 cells in vitro. A single intracranial injection of EGFP-oHSV-1 in established GL261 tumors significantly prolongs survival in all treated mice compared to placebo treatment. Notably, 45% of treated mice became long-term survivors, and rejected GL261 cells upon rechallenge in the contralateral brain hemisphere, indicating an anamnestic antitumoral immune response. Post-mortem analysis revealed a profound modification of the tumor microenvironment with increased infiltration of CD4 + and CD8 + T lymphocytes, intertumoral vascular collapse and activation and redistribution of macrophage, microglia, and astroglia in the tumor area, with the formation of intense fibrotic tissue suggestive of complete rejection in long-term survivor mice.

CONCLUSIONS

EGFP-oHSV1 demonstrates potent antitumoral activity in an immunocompetent GBM model as a monotherapy, resulting from direct cell killing combined with the stimulation of a protective adaptive immune response. These results open the way to possible application of our strategy in clinical setting.

Effects of intratumoral microbiota on tumorigenesis, anti-tumor immunity, and microbe-based cancer therapy

Intratumoral microbiota (IM) has emerged as a significant component of the previously thought sterile tumor microenvironment (TME), exerting diverse functions in tumorigenesis and immune modulation. This review outlines the historical background, classification, and diversity of IM, elucidating its pivotal roles in oncogenicity, cancer development, and progression, alongside its influence on anti-tumor immunity. The signaling pathways through which IM impacts tumorigenesis and immunity, including reactive oxygen species (ROS), β-catenin, stimulator of interferon genes (STING), and other pathways [NF-κB, Toll-like receptor (TLR), complement, RhoA/ROCK, PKR-like ER kinase (PERK)], are discussed comprehensively. Furthermore, we briefly introduce the clinical implications of IM, emphasizing its potential as a target for novel cancer therapies, diagnostic biomarkers, and prognostic indicators. Notably, microbe-based therapeutic strategies such as fecal microbiome transplantation (FMT), probiotics regulation, bacteriotherapy, bacteriophage therapy, and oncolytic virotherapy are highlighted. These strategies hold promise for enhancing the efficacy of current cancer treatments and warrant further exploration in clinical settings.

Enhanced treatment of breast cancer brain metastases with oncolytic virus expressing anti-CD47 antibody and temozolomide

Limited therapeutic options are available for patients with breast cancer brain metastases (BCBM), and thus there is an urgent need for novel treatment approaches. We previously engineered an effective oncolytic herpes simplex virus 1 (oHSV) expressing a full-length anti-CD47 monoclonal antibody (mAb) with a human IgG1 scaffold (OV-αCD47-G1) that was used to treat both ovarian cancer and glioblastoma. Here, we demonstrate that the combination of OV-αCD47-G1 and temozolomide (TMZ) improve outcomes in preclinical models of BCBM. The combination of TMZ with OV-αCD47-G1 synergistically increased macrophage phagocytosis against breast tumor cells and led to greater activation of NK cell cytotoxicity. In addition, the combination of OV-αCD47-G1 with TMZ significantly prolonged the survival of tumor-bearing mice when compared with TMZ or OV-αCD47-G1 alone. Combination treatment with the mouse counterpart of OV-αCD47-G1, termed OV-A4-IgG2b, also enhanced mouse macrophage phagocytosis, NK cell cytotoxicity, and survival in an immunocompetent model of mice bearing BCBM compared with TMZ or OV-A4-IgG2b alone. Collectively, these results suggest that OV-αCD47-G1 combined with TMZ should be explored in patients with BCBM.

Consensus review on strategies to improve delivery across the blood-brain barrier including focused ultrasound

Drug delivery to the central nervous system (CNS) has been a major challenge for CNS tumors due to the impermeability of the blood-brain barrier (BBB). There has been a multitude of techniques aimed at overcoming the BBB obstacle aimed at utilizing natural transport mechanisms or bypassing the BBB which we review here. Another approach that has generated recent interest in the recently published literature is to use new technologies (Laser Interstitial Thermal Therapy, LITT; or Low-Intensity Focused Ultrasound, LIFU) to temporarily increase BBB permeability. This review overviews the advantages, disadvantages, and major advances of each method. LIFU has been a major area of research to allow for chemotherapeutics to cross the BBB which has a particular emphasis in this review. While most of the advances remain in animal studies, there are an increasing number of translational clinical trials that will have results in the next few years.

Combination Immunotherapy with Vaccine and Oncolytic HSV Virotherapy Is Time Dependent

Oncolytic virotherapy or immunovirotherapy is a strategy that utilizes viruses to selectively infect and kill tumor cells while also stimulating an immune response against the tumor. Early clinical trials in both pediatric and adult patients using oncolytic herpes simplex viruses (oHSV) have demonstrated safety and promising efficacy; however, combinatorial strategies designed to enhance oncolysis while also promoting durable T-cell responses for sustaining disease remission are likely required. We hypothesized that combining the direct tumor cell killing and innate immune stimulation by oHSV with a vaccine that promotes T cell-mediated immunity may lead to more durable tumor regression. To this end, we investigated the preclinical efficacy and potential synergy of combining oHSV with a self-assembling nanoparticle vaccine codelivering peptide antigens and Toll-like receptor 7 and 8 agonists (referred to as SNAPvax),which induces robust tumor-specific T-cell immunity. We then assessed how timing of the treatments (i.e., vaccine before or after oHSV) impacts T-cell responses, viral replication, and preclinical efficacy. The sequence of treatments was critical, as survival was significantly enhanced when the SNAPvax vaccine was given prior to oHSV. Increased clinical efficacy was associated with reduced tumor volume and increases in virus replication and tumor antigen-specific CD8+ T cells. These findings substantiate the criticality of combination immunotherapy timing and provide preclinical support for combining SNAPvax with oHSV as a promising treatment approach for both pediatric and adult tumors.

Abscopal effect: from a rare phenomenon to a new frontier in cancer therapy

Radiotherapy (RT) controls local lesions, meantime it has the capability to induce systemic response to inhibit distant, metastatic, non-radiated tumors, which is referred to as the "abscopal effect". It is widely recognized that radiotherapy can stimulate systemic immune response. This provides a compelling theoretical basis for the combination of immune therapy combined with radiotherapy(iRT). Indeed, this phenomenon has also been observed in clinical treatment, bringing significant clinical benefits to patients, and a series of basic studies are underway to amplify this effect. However, the molecular mechanisms of immune response induced by RT, determination of the optimal treatment regimen for iRT, and how to amplify the abscopal effect. In order to amplify and utilize this effect in clinical management, these key issues require to be well addressed; In this review, we comprehensively summarize the growing consensus and emphasize the emerging limitations of enhancing the abscopal effect with radiotherapy or immunotherapy. Finally, we discuss the prospects and barriers to the current clinical translational applications.

Antigen escape in CAR-T cell therapy: Mechanisms and overcoming strategies

Chimeric antigen receptor T (CAR-T) cell therapy has shown promise in treating hematological malignancies and certain solid tumors. However, its efficacy is often hindered by negative relapses resulting from antigen escape. This review firstly elucidates the mechanisms underlying antigen escape during CAR-T cell therapy, including the enrichment of pre-existing target-negative tumor clones, antigen gene mutations or alternative splicing, deficits in antigen processing, antigen redistribution, lineage switch, epitope masking, and trogocytosis-mediated antigen loss. Furthermore, we summarize various strategies to overcome antigen escape, evaluate their advantages and limitations, and propose future research directions. Thus, we aim to provide valuable insights to enhance the effectiveness of CAR-T cell therapy.

oHSV2-mGM repolarizes TAMs and cooperates with αPD1 to reprogram the immune microenvironment of residual cancer after radiofrequency ablation

BACKGROUND

Due to the size and location of the tumor, incomplete radiofrequency ablation (iRFA) of the target tumor inhibits tumor immunity. In this study, a murine herpes simplex virus (oHSV2-mGM) armed with granulocyte-macrophage colony-stimulating factor (GM-CSF) was constructed to explore its effect on innate and adaptive immunity during iRFA, and the inhibitory effect of programmed cell death-1 (PD1) on tumor.

METHODS

We verified the polarization and activation of RAW264.7 cells mediated by oHSV2-mGM in vitro. Subsequently, we evaluated the efficacy of oHSV2-mGM alone and in combination with αPD1 in the treatment of residual tumors after iRFA in two mouse models. RNA-seq was used to characterize the changes of tumor microenvironment.

RESULTS

oHSV2-mGM lysate effectively stimulated RAW264.7 cells to polarize into M1 cells and activated M1 phenotypic function. In the macrophage clearance experiment, oHSV2-mGM activated the immune response of tumor in mice. The results in vivo showed that oHSV2-mGM showed better anti-tumor effect in several mouse tumor models. Finally, oHSV2-mGM combined with PD1 antibody can further enhance the anti-tumor effect of oHSV2-mGM and improve the complete remission rate of tumor in mice.

CONCLUSION

The application of oHSV2-mGM leads to the profound remodeling of the immune microenvironment of residual tumors. oHSV2-mGM also works in synergy with PD1 antibody to achieve complete remission of tumors that do not respond well to monotherapy at immune checkpoints. Our results support the feasibility of recombinant oncolytic virus in the treatment of residual tumors after iRFA, and propose a new strategy for oncolytic virus treatment of tumors.

Emerging role of immunogenic cell death in cancer immunotherapy: Advancing next-generation CAR-T cell immunotherapy by combination

Immunogenic cell death (ICD) is a stress-driven form of regulated cell death (RCD) in which dying tumor cells' specific signaling pathways are activated to release damage-associated molecular patterns (DAMPs), leading to the robust anti-tumor immune response as well as a reversal of the tumor immune microenvironment from "cold" to "hot". Chimeric antigen receptor (CAR)-T cell therapy, as a landmark in anti-tumor immunotherapy, plays a formidable role in hematologic malignancies but falls short in solid tumors. The Gordian knot of CAR-T cells for solid tumors includes but is not limited to, tumor antigen heterogeneity or absence, physical and immune barriers of tumors. The combination of ICD induction therapy and CAR-T cell immunotherapy is expected to promote the intensive use of CAR-T cell in solid tumors. In this review, we summarize the characteristics of ICD, stress-responsive mechanism, and the synergistic effect of various ICD-based therapies with CAR-T cells to effectively improve anti-tumor capacity.

Nanomedicine-based cancer immunotherapy: a bibliometric analysis of research progress and prospects

Despite the increasing number of studies on nanomedicine-based cancer immunotherapy, the overall research trends in this field remain inadequately characterized. This study aims to evaluate the research trends and hotspots in nanomedicine-based cancer immunotherapy through a bibliometric analysis. As of March 31, 2024, relevant publications were retrieved from the Web of Science Core Collection. Analytical tools including VOSviewer, CiteSpace, and an online bibliometric analysis platform were employed. A total of 5,180 publications were analyzed. The study reveals geographical disparities in research output, with China and the United States being the leading contributors. Institutionally, the Chinese Academy of Sciences, University of Chinese Academy of Sciences, and Sichuan University are prominent contributors. Authorship analysis identifies key researchers, with Liu Zhuang being the most prolific author. "ACS Nano" and the "Journal of Controlled Release and Biomaterials" are identified as the leading journals in the field. Frequently occurring keywords include "cancer immunotherapy" and "drug delivery." Emerging frontiers in the field, such as "mRNA vaccine," "sonodynamic therapy," "oral squamous cell carcinoma," "STING pathway,"and "cGAS-STING pathway," are experiencing rapid growth. This study aims to provide new insights to advance scientific research and clinical applications in nanomedicine-based cancer immunotherapy.

Immunotherapy for colorectal cancer

Colorectal cancer is the third most common cancer and the second most lethal cancer in the world. The main cause of the disease is due to dietary and behavioral factors. The treatment of this complex disease is mainly based on traditional treatments, including surgery, radiotherapy, and chemotherapy. Due to its high prevalence and high morbidity, more effective treatments with fewer side effects are urgently needed. In recent years, immunotherapy has become a potential therapeutic alternative and one of the fastest-developing treatments. Immunotherapy inhibits tumor growth by activating or enhancing the immune system to recognize and attack cancer cells. This review presents the latest immunotherapies for immune checkpoint inhibitors, cell therapy, tumor-infiltrating lymphocytes, and oncolytic viruses. Some of these have shown promising results in clinical trials and are used in clinical treatment.

Antitumor Effect and Immunomodulatory Mechanism of "Oncolytic Extracellular Vesicles"

Enhancing the antitumor immune response and targeting ability of oncolytic viruses will improve the effect of tumor immunotherapy. Through infecting neural stem cells (NSCs) with a capsid dual-modified oncolytic adenovirus (CRAd), we obtained and characterized the "oncolytic extracellular vesicles" (CRAdEV) with improved targeted infection and tumor killing activity compared with CRAd. Both ex vivo and in vivo studies revealed that CRAdEV activated innate immune cells and importantly enhanced the immunomodulatory effect compared to CRAd. We found that CRAdEV effectively increased the number of DCs and activated CD4+ and CD8+ T cells, significantly increased the number and activation of B cells, and produced higher levels of tumor-specific antibodies, thus eliciting enhanced antitumor activity compared with CRAd in a B16 xenograft immunocompetent mice model. This study provides a novel approach to oncolytic adenovirus modification and demonstrates the potential of "oncolytic extracellular vesicles" in antitumor immunotherapy.

Cancer immunotherapy and its facilitation by nanomedicine

Cancer immunotherapy has sparked a wave of cancer research, driven by recent successful proof-of-concept clinical trials. However, barriers are emerging during its rapid development, including broad adverse effects, a lack of reliable biomarkers, tumor relapses, and drug resistance. Integration of nanomedicine may ameliorate current cancer immunotherapy. Ultra-large surface-to-volume ratio, extremely small size, and easy modification surface of nanoparticles enable them to selectively detect cells and kill cancer cells in vivo. Exciting synergistic applications of the two approaches have emerged in treating various cancers at the intersection of cancer immunotherapy and cancer nanomedicine, indicating the potential that the combination of these two therapeutic modalities can lead to new paradigms in the treatment of cancer. This review discusses the status of current immunotherapy and explores the possible opportunities that the nanomedicine platform can make cancer immunotherapy more powerful and precise by synergizing the two approaches.

The Oncolytic virus VT1092M and an Anti-PD-L1 antibody synergize to induce systemic antitumor immunity in a murine bilateral tumor model

This study investigated the synergistic potential of an oncolytic herpes simplex virus armed with interleukin 12 (VT1092M) in combination with immune checkpoint inhibitors for enhancing antitumor responses. The potential of this combination treatment to induce systemic antitumor immunity was assessed using bilateral subcutaneous tumor and tumor re-challenge mouse models. The antitumor efficacy of various OV and ICI treatment combinations and the underlying mechanisms were explored through diverse analytical techniques, including flow cytometry and RNA sequencing. Using VT1092M, either alone or in combination with an anti-PD-L1 antibody, significantly reduced the sizes of both the injected and untreated abscopal tumors in a bilateral tumor mouse model. The combination therapy demonstrated superior antitumor efficacy to the other treatment conditions tested, which was accompanied by an increase in T cell numbers and CD8+T cell activation. Results from the survival and tumor re-challenge experiments showed that the combination therapy elicited long-term, tumor-specific immune responses, which were associated with tumor clearance and prolonged survival. Immune cell depletion assays identified CD8+T cells as the crucial mediators of systemic antitumor immunity during combination therapy. In conclusion, the combination of VT1092M and PD-L1 blockade emerged as a potent inducer of antitumor immune responses, surpassing the efficacy of each monotherapy. This synergistic approach holds promise for achieving robust and sustained antitumor immunity, with potential implications for preventing tumor metastasis in patients with cancer.

Brain gliomas: Diagnostic and therapeutic issues and the prospects of drug-targeted nano-delivery technology

Glioma is the most common intracranial malignant tumor, with severe difficulty in treatment and a low patient survival rate. Due to the heterogeneity and invasiveness of tumors, lack of personalized clinical treatment design, and physiological barriers, it is often difficult to accurately distinguish gliomas, which dramatically affects the subsequent diagnosis, imaging treatment, and prognosis. Fortunately, nano-delivery systems have demonstrated unprecedented capabilities in diagnosing and treating gliomas in recent years. They have been modified and surface modified to efficiently traverse BBB/BBTB, target lesion sites, and intelligently release therapeutic or contrast agents, thereby achieving precise imaging and treatment. In this review, we focus on nano-delivery systems. Firstly, we provide an overview of the standard and emerging diagnostic and treatment technologies for glioma in clinical practice. After induction and analysis, we focus on summarizing the delivery methods of drug delivery systems, the design of nanoparticles, and their new advances in glioma imaging and treatment in recent years. Finally, we discussed the prospects and potential challenges of drug-delivery systems in diagnosing and treating glioma.

Advancements in Immunotherapy for Breast Cancer: Mechanisms, Efficacy, and Future Directions

Breast cancer is a major global health challenge characterized by its diverse biological behavior and varying treatment responses. Traditional therapies, including surgery, radiation, chemotherapy, hormonal therapy, and targeted therapy, have significantly advanced breast cancer treatment but are often limited by issues such as resistance, side effects, and variable efficacy. Immunotherapy has emerged as a transformative approach, leveraging the body's immune system to target and eliminate cancer cells. This review provides a comprehensive overview of recent advancements in immunotherapy for breast cancer, detailing the mechanisms of various therapeutic strategies, including checkpoint inhibitors, monoclonal antibodies, cancer vaccines, adoptive cell therapy, and oncolytic virus therapy. We evaluate the efficacy of these approaches in different stages of breast cancer, highlighting successes and challenges encountered in clinical settings. The review also addresses the current limitations of immunotherapy, such as treatment-related adverse effects, resistance mechanisms, and issues of cost and accessibility. We discuss promising future directions, including emerging targets, combination therapies, and personalized medicine approaches. By integrating recent research and clinical trial data, this review aims to elucidate the potential of immunotherapy to revolutionize breast cancer treatment, offering insights into its future role in improving patient outcomes and shaping the landscape of oncological care.

TG6050, an oncolytic vaccinia virus encoding interleukin-12 and anti-CTLA-4 antibody, favors tumor regression via profound immune remodeling of the tumor microenvironment

BACKGROUND

TG6050 was designed as an improved oncolytic vector, combining the intrinsic properties of vaccinia virus to selectively replicate in tumors with the tumor-restricted expression of recombinant immune effectors to modify the tumor immune phenotype. These properties might be of particular interest for "cold" tumors, either poorly infiltrated or infiltrated with anergic T cells.

METHODS

 TG6050, an oncolytic vaccinia virus encodes single-chain human interleukin-12 (hIL-12) and full-length anti-cytotoxic T-lymphocyte-associated antigen-4 (@CTLA-4) monoclonal antibody. The relevant properties of TG6050 (replication, cytopathy, transgenes expression and functionality) were extensively characterized in vitro. The biodistribution and pharmacokinetics of the viral vector, @CTLA-4 and IL-12, as well as antitumoral activities (alone or combined with immune checkpoint inhibitors) were investigated in several "hot" (highly infiltrated) and "cold" (poorly infiltrated) syngeneic murine tumor models. The mechanism of action was deciphered by monitoring both systemic and intratumoral immune responses, and by tumor transcriptome analysis. The safety of TG6050 after repeated intravenous administrations was evaluated in cynomolgus monkeys, with a focus on the level of circulating IL-12.

RESULTS

Multiplication and propagation of TG6050 in tumor cells in vitro and in vivo were associated with local expression of functional IL-12 and @CTLA-4. This dual mechanism translated into a strong antitumoral activity in both "cold" and "hot" tumor models (B16F10, LLC1 or EMT6, CT26, respectively) that was further amplified when combined with anti-programmed cell death protein-1. Analysis of changes in the tumor microenvironment (TME) after treatment with TG6050 showed increases in interferon-gamma, of CD8+T cells, and of M1/M2 macrophages ratio, as well as a drastic decrease of regulatory T cells. These local modifications were observed alongside bolstering a systemic and specific antitumor adaptive immune response. In toxicology studies, TG6050 did not display any observable adverse effects in cynomolgus monkeys.

CONCLUSIONS

TG6050 effectively delivers functional IL-12 and @CTLA-4 into the tumor, resulting in strong antitumor activity. The shift towards an inflamed TME correlated with a boost in systemic antitumor T cells. The solid preclinical data and favorable benefit/risk ratio paved the way for the clinical evaluation of TG6050 in metastatic non-small cell lung cancer (NCT05788926 trial in progress).

An oncolytic HSV-1 armed with Visfatin enhances antitumor effects by remodeling tumor microenvironment against murine pancreatic cancer

Oncolytic viruses (OVs) have shown potential in converting a "cold" tumor into a "hot" one and exhibit effectiveness in various cancer types. However, only a subset of patients respond to oncolytic virotherapy. It is important to understand the resistance mechanisms to OV treatment in pancreatic ductal adenocarcinoma (PDAC) to engineer oncolytic viruses. In this study, we used transcriptome RNA sequencing (RNA-seq) to identify Visfatin, which was highly expressed in the responsive tumors following OV treatment. To explore the antitumor efficacy, we modified OV-mVisfatin, which effectively inhibited tumor growth. For the first time, we revealed that Visfatin promoted the antitumor efficacy of OV by remodeling the tumor microenvironment, which involved enhancing CD8+ T cell and DC cell infiltration and activation, repolarizing macrophages towards the M1-like phenotype, and decreasing Treg cells using single-cell RNA sequencing (scRNA-seq) and flow cytometry. Furthermore, PD-1 blockade significantly enhanced OV-mVisfatin antitumor efficacy, offering a promising new therapeutic strategy for PDAC.

3D bioprinted CRC model brings to light the replication necessity of an oncolytic vaccinia virus encoding FCU1 gene to exert an efficient anti-tumoral activity

The oncolytic virus represents a promising therapeutic strategy involving the targeted replication of viruses to eliminate cancer cells, while preserving healthy ones. Despite ongoing clinical trials, this approach encounters significant challenges. This study delves into the interaction between an oncolytic virus and extracellular matrix mimics (ECM mimics). A three-dimensional colorectal cancer model, enriched with ECM mimics through bioprinting, was subjected to infection by an oncolytic virus derived from the vaccinia virus (oVV). The investigation revealed prolonged expression and sustained oVV production. However, the absence of a significant antitumor effect suggested that the virus's progression toward non-infected tumoral clusters was hindered by the ECM mimics. Effective elimination of tumoral cells was achieved by introducing an oVV expressing FCU1 (an enzyme converting the prodrug 5-FC into the chemotherapeutic compound 5-FU) alongside 5-FC. Notably, this efficacy was absent when using a non-replicative vaccinia virus expressing FCU1. Our findings underscore then the crucial role of oVV proliferation in a complex ECM mimics. Its proliferation facilitates payload expression and generates a bystander effect to eradicate tumors. Additionally, this study emphasizes the utility of 3D bioprinting for assessing ECM mimics impact on oVV and demonstrates how enhancing oVV capabilities allows overcoming these barriers. This showcases the potential of 3D bioprinting technology in designing purpose-fit models for such investigations.

Oncolytic Viral Therapy in Osteosarcoma

Primary bone malignancies, including osteosarcoma (OS), are rare but aggressive. Current OS treatment, involving surgical resection and chemotherapy, has improved survival for non-metastatic cases but remains ineffective for recurrent or metastatic OS. Oncolytic viral therapy (OVT) is a promising alternative, using naturally occurring or genetically modified viruses to selectively target and lyse cancer cells and induce a robust immune response against remaining OS cells. Various oncolytic viruses (OVs), such as adenovirus, herpes simplex virus, and measles virus, have demonstrated efficacy in preclinical OS models. Combining OVT with other therapeutics, such as chemotherapy or immunotherapy, may further improve outcomes. Despite these advances, challenges in reliability of preclinical models, safety, delivery, and immune response must be addressed to optimize OVT for clinical use. Future research should focus on refining delivery methods, exploring combination treatments, and clinical trials to ensure OVT's efficacy and safety for OS. Overall, OVT represents a novel approach with the potential to drastically improve survival outcomes for patients with OS.

Enhancing cancer therapy: the integration of oncolytic virus therapy with diverse treatments

As one of the significant challenges to human health, cancer has long been a focal point in medical treatment. With ongoing advancements in the field of medicine, numerous methodologies for cancer therapy have emerged, among which oncolytic virus therapy has gained considerable attention. However, oncolytic viruses still exhibit limitations. Combining them with various therapies can further enhance the efficacy of cancer treatment, offering renewed hope for patients. In recent research, scientists have recognized the promising prospect of amalgamating oncolytic virus therapy with diverse treatments, potentially surmounting the restrictions of singular approaches. The central concept of this combined therapy revolves around leveraging oncolytic virus to incite localized tumor inflammation, augmenting the immune response for immunotherapeutic efficacy. Through this approach, the patient's immune system can better recognize and eliminate cancer cells, simultaneously reducing tumor evasion mechanisms against the immune system. This review delves deeply into the latest research progress concerning the integration of oncolytic virus with diverse treatments and its role in various types of cancer therapy. We aim to analyze the mechanisms, advantages, potential challenges, and future research directions of this combination therapy. By extensively exploring this field, we aim to instill renewed hope in the fight against cancer.

The investigation of oncolytic viruses in the field of cancer therapy

Oncolytic viruses (OVs) have emerged as a potential strategy for tumor treatment due to their ability to selectively replicate in tumor cells, induce apoptosis, and stimulate immune responses. However, the therapeutic efficacy of single OVs is limited by the complexity and immunosuppressive nature of the tumor microenvironment (TME). To overcome these challenges, engineering OVs has become an important research direction. This review focuses on engineering methods and multi-modal combination therapies for OVs aimed at addressing delivery barriers, viral phagocytosis, and antiviral immunity in tumor therapy. The engineering approaches discussed include enhancing in vivo immune response, improving replication efficiency within the tumor cells, enhancing safety profiles, and improving targeting capabilities. In addition, this review describes the potential mechanisms of OVs combined with radiotherapy, chemotherapy, cell therapy and immune checkpoint inhibitors (ICIs), and summarizes the data of ongoing clinical trials. By continuously optimizing engineering strategies and combination therapy programs, we can achieve improved treatment outcomes and quality of life for cancer patients.

Systemic delivery of oncolytic herpes virus using CAR-T cells enhances targeting of antitumor immuno-virotherapy

Recent studies have indicated that combining oncolytic viruses with CAR-T cells in therapy has shown superior anti-tumor effects, representing a promising approach. Nonetheless, the localized delivery method of intratumoral injection poses challenges for treating metastatic tumors or distal tumors that are difficult to reach. To address this obstacle, we employed HSV-1-infected CAR-T cells, which systemically delivery HSV into solid tumors. The biological function of CAR-T cells remained intact after loading them with HSV for a period of three days. In both immunocompromised and immunocompetent GBM orthotopic mouse models, B7-H3 CAR-T cells effectively delivered HSV to tumor lesions, resulting in enhanced T-cell infiltration and significantly prolonged survival in mice. We also employed a bilateral subcutaneous tumor model and observed that the group receiving intratumoral virus injection exhibited a significant reduction in tumor volume on the injected side, while the group receiving intravenous infusion of CAR-T cells carrying HSV displayed suppressed tumor growth on both sides. Hence, CAR-THSV cells offer notable advantages in the systemic delivery of HSV to distant tumors. In conclusion, our findings emphasize the potential of CAR-T cells as carriers for HSV, presenting significant advantages for oncolytic virotherapy targeting distant tumors.

Closed-loop experiments and brain machine interfaces with multiphoton microscopy

In the field of neuroscience, the importance of constructing closed-loop experimental systems has increased in conjunction with technological advances in measuring and controlling neural activity in live animals. We provide an overview of recent technological advances in the field, focusing on closed-loop experimental systems where multiphoton microscopy-the only method capable of recording and controlling targeted population activity of neurons at a single-cell resolution in vivo-works through real-time feedback. Specifically, we present some examples of brain machine interfaces (BMIs) using in vivo two-photon calcium imaging and discuss applications of two-photon optogenetic stimulation and adaptive optics to real-time BMIs. We also consider conditions for realizing future optical BMIs at the synaptic level, and their possible roles in understanding the computational principles of the brain.

Current approaches in glioblastoma multiforme immunotherapy

Glioblastoma multiform (GBM) is the most prevalent CNS (central nervous system) tumor in adults, with an average survival length shorter than 2 years and rare metastasis to organs other than CNS. Despite extensive attempts at surgical resecting, the inherently permeable nature of this disease has rendered relapse nearly unavoidable. Thus, immunotherapy is a feasible alternative, as stimulated immune cells can enter into the remote and inaccessible tumor cells. Immunotherapy has revolutionized patient upshots in various malignancies and might introduce different effective ways for GBM patients. Currently, researchers are exploring various immunotherapeutic strategies in patients with GBM to target both the innate and acquired immune responses. These approaches include reprogrammed tumor-associated macrophages, the use of specific antibodies to inhibit tumor progression and metastasis, modifying tumor-associated macrophages with antibodies, vaccines that utilize tumor-specific dendritic cells to activate anti-tumor T cells, immune checkpoint inhibitors, and enhanced T cells that function against tumor cells. Despite these findings, there is still room for improving the response faults of the many currently tested immunotherapies. This study aims to review the currently used immunotherapy approaches with their molecular mechanisms and clinical application in GBM.

Oncolytic Activity of Sindbis Virus with the Help of GM-CSF in Hepatocellular Carcinoma

Hepatocellular carcinoma is a refractory tumor with poor prognosis and high mortality. Many oncolytic viruses are currently being investigated for the treatment of hepatocellular carcinoma. Based on previous studies, we constructed a recombinant GM-CSF-carrying Sindbis virus, named SINV-GM-CSF, which contains a mutation (G to S) at amino acid 285 in the nsp1 protein of the viral vector. The potential of this mutated vector for liver cancer therapy was verified at the cellular level and in vivo, respectively, and the changes in the tumor microenvironment after treatment were also described. The results showed that the Sindbis virus could effectively infect hepatocellular carcinoma cell lines and induce cell death. Furthermore, the addition of GM-CSF enhanced the tumor-killing effect of the Sindbis virus and increased the number of immune cells in the intra-tumor microenvironment during the treatment. In particular, SINV-GM-CSF was able to efficiently kill tumors in a mouse tumor model of hepatocellular carcinoma by regulating the elevation of M1-type macrophages (which have a tumor-resistant ability) and the decrease in M2-type macrophages (which have a tumor-promoting capacity). Overall, SINV-GM-CSF is an attractive vector platform with clinical potential for use as a safe and effective oncolytic virus.

The Role of Natural Killer Cells in Oncolytic Virotherapy: Friends or Foes?

Oncolytic virotherapy (OVT) has emerged as a promising cancer immunotherapy, and is capable of potentiating other immunotherapies due to its capacity to increase tumor immunogenicity and to boost host antitumor immunity. Natural killer (NK) cells are a critical cellular component for mediating the antitumor response, but hold a mixed reputation for their role in mediating the therapeutic efficacy of OVT. This review will discuss the pros and cons of how NK cells impact OVT, and how to harness this knowledge for the development of effective strategies that could modulate NK cells to improve OVT-based therapeutic outcomes.

Tuning cellular metabolism for cancer virotherapy

Oncolytic viruses (OVs) represent an emerging immunotherapeutic strategy owing to their capacity for direct tumor lysis and induction of antitumor immunity. However, hurdles like transient persistence and moderate efficacy necessitate innovative approaches. Metabolic remodeling has recently gained prominence as a strategic intervention, wherein OVs or combination regimens could reprogram tumor and immune cell metabolism to enhance viral replication and oncolysis. In this review, we summarize recent advances in strategic reprogramming of tumor and immune cell metabolism to enhance OV-based immunotherapies. Specific tactics include engineering viruses to target glycolytic, glutaminolytic, and nucleotide synthesis pathways in cancer cells, boosting viral replication and tumor cell death. Additionally, rewiring T cell and NK cell metabolism of lipids, amino acids, and carbohydrates shows promise to enhance antitumor effects. Further insights are discussed to pave the way for the clinical implementation of metabolically enhanced oncolytic platforms, including balancing metabolic modulation to limit antiviral responses while promoting viral persistence and tumor clearance.

Expression of tumor antigens within an oncolytic virus enhances the anti-tumor T cell response

Although patients benefit from immune checkpoint inhibition (ICI) therapy in a broad variety of tumors, resistance may arise from immune suppressive tumor microenvironments (TME), which is particularly true of hepatocellular carcinoma (HCC). Since oncolytic viruses (OV) can generate a highly immune-infiltrated, inflammatory TME, OVs could potentially restore ICI responsiveness via recruitment, priming, and activation of anti-tumor T cells. Here we find that on the contrary, an oncolytic vesicular stomatitis virus, expressing interferon-ß (VSV-IFNß), antagonizes the effect of anti-PD-L1 therapy in a partially anti-PD-L1-responsive model of HCC. Cytometry by Time of Flight shows that VSV-IFNß expands dominant anti-viral effector CD8 T cells with concomitant relative disappearance of anti-tumor T cell populations, which are the target of anti-PD-L1. However, by expressing a range of HCC tumor antigens within VSV, combination OV and anti-PD-L1 therapeutic benefit could be restored. Our data provide a cautionary message for the use of highly immunogenic viruses as tumor-specific immune-therapeutics by showing that dominant anti-viral T cell responses can inhibit sub-dominant anti-tumor T cell responses. However, through encoding tumor antigens within the virus, oncolytic virotherapy can generate anti-tumor T cell populations upon which immune checkpoint blockade can effectively work.

The recent advancements in protein nanoparticles for immunotherapy

In recent years, the advancement of nanoparticle-based immunotherapy has introduced an innovative strategy for combatting diseases. Compared with other types of nanoparticles, protein nanoparticles have obtained substantial attention owing to their remarkable biocompatibility, biodegradability, ease of modification, and finely designed spatial structures. Nature provides several protein nanoparticle platforms, including viral capsids, ferritin, and albumin, which hold significant potential for disease treatment. These naturally occurring protein nanoparticles not only serve as effective drug delivery platforms but also augment antigen delivery and targeting capabilities through techniques like genetic modification and covalent conjugation. Motivated by nature's originality and driven by progress in computational methodologies, scientists have crafted numerous protein nanoparticles with intricate assembly structures, showing significant potential in the development of multivalent vaccines. Consequently, both naturally occurring and de novo designed protein nanoparticles are anticipated to enhance the effectiveness of immunotherapy. This review consolidates the advancements in protein nanoparticles for immunotherapy across diseases including cancer and other diseases like influenza, pneumonia, and hepatitis.

Emerging Targets and Therapeutics in Immuno-Oncology: Insights from Landscape Analysis

In the ever-evolving landscape of cancer research, immuno-oncology stands as a beacon of hope, offering novel avenues for treatment. This study capitalizes on the vast repository of immuno-oncology-related scientific documents within the CAS Content Collection, totaling over 350,000, encompassing journals and patents. Through a pioneering approach melding natural language processing with the CAS indexing system, we unveil over 300 emerging concepts, depicted in a comprehensive "Trend Landscape Map". These concepts, spanning therapeutic targets, biomarkers, and types of cancers among others, are hierarchically organized into eight major categories. Delving deeper, our analysis furnishes detailed quantitative metrics showcasing growth trends over the past three years. Our findings not only provide valuable insights for guiding future research endeavors but also underscore the merit of tapping the vast and unparalleled breadth of existing scientific information to derive profound insights.

Stepping forward: T-cell redirecting bispecific antibodies in cancer therapy

T cell-redirecting bispecific antibodies are specifically designed to bind to tumor-associated antigens, thereby engaging with CD3 on the T cell receptor. This linkage between tumor cells and T cells actively triggers T cell activation and initiates targeted killing of the identified tumor cells. These antibodies have emerged as one of the most promising avenues within tumor immunotherapy. However, despite success in treating hematological malignancies, significant advancements in solid tumors have yet to be explored. In this review, we aim to address the critical challenges associated with T cell-redirecting bispecific antibodies and explore novel strategies to overcome these obstacles, with the ultimate goal of expanding the application of this therapy to include solid tumors.

Immune landscape and response to oncolytic virus-based immunotherapy

Oncolytic virus (OV)-based immunotherapy has emerged as a promising strategy for cancer treatment, offering a unique potential to selectively target malignant cells while sparing normal tissues. However, the immunosuppressive nature of tumor microenvironment (TME) poses a substantial hurdle to the development of OVs as effective immunotherapeutic agents, as it restricts the activation and recruitment of immune cells. This review elucidates the potential of OV-based immunotherapy in modulating the immune landscape within the TME to overcome immune resistance and enhance antitumor immune responses. We examine the role of OVs in targeting specific immune cell populations, including dendritic cells, T cells, natural killer cells, and macrophages, and their ability to alter the TME by inhibiting angiogenesis and reducing tumor fibrosis. Additionally, we explore strategies to optimize OV-based drug delivery and improve the efficiency of OV-mediated immunotherapy. In conclusion, this review offers a concise and comprehensive synopsis of the current status and future prospects of OV-based immunotherapy, underscoring its remarkable potential as an effective immunotherapeutic agent for cancer treatment.

Immune checkpoint inhibitors: breakthroughs in cancer treatment

Over the past two decades, immunotherapies have increasingly been considered as first-line treatments for most cancers. One such treatment is immune checkpoint blockade (ICB), which has demonstrated promising results against various solid tumors in clinical trials. Monoclonal antibodies (mAbs) are currently available as immune checkpoint inhibitors (ICIs). These ICIs target specific immune checkpoints, including cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Clinical trial results strongly support the feasibility of this immunotherapeutic approach. However, a substantial proportion of patients with cancer develop resistance or tolerance to treatment, owing to tumor immune evasion mechanisms that counteract the host immune response. Consequently, substantial research focus has been aimed at identifying additional ICIs or synergistic inhibitory receptors to enhance the effectiveness of anti-PD-1, anti-programmed cell death ligand 1 (anti-PD-L1), and anti-CTLA-4 treatments. Recently, several immune checkpoint molecular targets have been identified, such as T cell immunoreceptor with Ig and ITIM domains (TIGIT), mucin domain containing-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), V-domain immunoglobulin suppressor of T cell activation (VISTA), B and T lymphocyte attenuator (BTLA), and signal-regulatory protein α (SIRPα). Functional mAbs targeting these molecules are under development. CTLA-4, PD-1/PD-L1, and other recently discovered immune checkpoint proteins with distinct structures are at the forefront of research. This review discusses these structures, as well as clinical progress in mAbs targeting these immune checkpoint molecules and their potential applications.

Immunosuppressive tumor microenvironment and immunotherapy of hepatocellular carcinoma: current status and prospectives

Hepatocellular carcinoma (HCC) is a major health concern worldwide, with limited therapeutic options and poor prognosis. In recent years, immunotherapies such as immune checkpoint inhibitors (ICIs) have made great progress in the systemic treatment of HCC. The combination treatments based on ICIs have been the major trend in this area. Recently, dual immune checkpoint blockade with durvalumab plus tremelimumab has also emerged as an effective treatment for advanced HCC. However, the majority of HCC patients obtain limited benefits. Understanding the immunological rationale and exploring novel ways to improve the efficacy of immunotherapy has drawn much attention. In this review, we summarize the latest progress in this area, the ongoing clinical trials of immune-based combination therapies, as well as novel immunotherapy strategies such as chimeric antigen receptor T cells, personalized neoantigen vaccines, oncolytic viruses, and bispecific antibodies.

Influence of Microbiota on Tumor Immunotherapy

The role of the microbiome in immunotherapy has recently garnered substantial attention, with molecular studies and clinical trials providing emerging evidence on the pivotal influence of the microbiota in enhancing therapeutic outcomes via immune response modulation. However, the impact of microbial communities can considerably vary across individuals and different immunotherapeutic approaches, posing prominent challenges in harnessing their potential. In this comprehensive review, we outline the current research applications in tumor immunotherapy and delve into the possible mechanisms through which immune function is influenced by microbial communities in various body sites, encompassing those in the gut, extraintestinal barrier, and intratumoral environment. Furthermore, we discuss the effects of diverse microbiome-based strategies, including probiotics, prebiotics, fecal microbiota transplantation, and the targeted modulation of specific microbial taxa, and antibiotic treatments on cancer immunotherapy. All these strategies potentially have a profound impact on immunotherapy and pave the way for personalized therapeutic approaches and predictive biomarkers.

Development of a novel, high-efficacy oncolytic herpes simplex virus type 1 platform equipped with two distinct retargeting modalities

To retarget oncolytic herpes simplex virus (oHSV) to cancer-specific antigens, we designed a novel, double-retargeted oHSV platform that uses single-chain antibodies (scFvs) incorporated into both glycoprotein H and a bispecific adapter expressed from the viral genome to mediate infection predominantly via tumor-associated antigens. Successful retargeting was achieved using a nectin-1-detargeted HSV that remains capable of interacting with herpesvirus entry mediator (HVEM), the second canonical HSV entry receptor, and is, therefore, recognized by the adapter consisting of the virus-binding N-terminal 82 residues of HVEM fused to the target-specific scFv. We tested both an epithelial cell adhesion molecule (EpCAM)- and a human epidermal growth factor receptor 2-specific scFv separately and together to target cells expressing one, the other, or both receptors. Our results show not only dose-dependent, target receptor-specific infection in vitro, but also enhanced virus spread compared with single-retargeted virus. In addition, we observed effective infection and spreading of the EpCAM double-retargeted virus in vivo. Remarkably, a single intravenous dose of the EpCAM-specific virus eliminated all detectable tumors in a subcutaneous xenograft model, and the same intravenous dose seemed to be harmless in immunocompetent FVB/N mice. Our findings suggest that our double-retargeted oHSV platform can provide a potent, versatile, and systemically deliverable class of anti-cancer therapeutics that specifically target cancer cells while ensuring safety.

CAR-NK cells in combination therapy against cancer: A potential paradigm

Various preclinical and a limited number of clinical studies of CAR-NK cells have shown promising results: efficient elimination of target cells without side effects similar to CAR-T therapy. However, the homing and infiltration abilities of CAR-NK cells are poor due to the inhibitory tumor microenvironment. From the perspective of clinical treatment strategies, combined with the biological and tumor microenvironment characteristics of NK cells, CAR-NK combination therapy strategies with anti-PD-1/PD-L1, radiotherapy and chemotherapy, kinase inhibitors, proteasome inhibitors, STING agonist, oncolytic virus, photothermal therapy, can greatly promote the proliferation, migration and cytotoxicity of the NK cells. In this review, we will summarize the targets selection, structure constructions and combinational therapies of CAR-NK cells for tumors to provide feasible combination strategies for overcoming the inhibitory tumor microenvironment and improving the efficacy of CAR-NK cells.

Insights into the glioblastoma tumor microenvironment: current and emerging therapeutic approaches

Glioblastoma (GB) is an intrusive and recurrent primary brain tumor with low survivability. The heterogeneity of the tumor microenvironment plays a crucial role in the stemness and proliferation of GB. The tumor microenvironment induces tumor heterogeneity of cancer cells by facilitating clonal evolution and promoting multidrug resistance, leading to cancer cell progression and metastasis. It also plays an important role in angiogenesis to nourish the hypoxic tumor environment. There is a strong interaction of neoplastic cells with their surrounding microenvironment that comprise several immune and non-immune cellular components. The tumor microenvironment is a complex network of immune components like microglia, macrophages, T cells, B cells, natural killer (NK) cells, dendritic cells and myeloid-derived suppressor cells, and non-immune components such as extracellular matrix, endothelial cells, astrocytes and neurons. The prognosis of GB is thus challenging, making it a difficult target for therapeutic interventions. The current therapeutic approaches target these regulators of tumor micro-environment through both generalized and personalized approaches. The review provides a summary of important milestones in GB research, factors regulating tumor microenvironment and promoting angiogenesis and potential therapeutic agents widely used for the treatment of GB patients.

Applications of Intravital Imaging in Cancer Immunotherapy

Currently, immunotherapy is one of the most effective treatment strategies for cancer. However, the efficacy of any specific anti-tumor immunotherapy can vary based on the dynamic characteristics of immune cells, such as their rate of migration and cell-to-cell interactions. Therefore, understanding the dynamics among cells involved in the immune response can inform the optimization and improvement of existing immunotherapy strategies. In vivo imaging technologies use optical microscopy techniques to visualize the movement and behavior of cells in vivo, including cells involved in the immune response, thereby showing great potential for application in the field of cancer immunotherapy. In this review, we briefly introduce the technical aspects required for in vivo imaging, such as fluorescent protein labeling, the construction of transgenic mice, and various window chamber models. Then, we discuss the elucidation of new phenomena and mechanisms relating to tumor immunotherapy that has been made possible by the application of in vivo imaging technology. Specifically, in vivo imaging has supported the characterization of the movement of T cells during immune checkpoint inhibitor therapy and the kinetic analysis of dendritic cell migration in tumor vaccine therapy. Finally, we provide a perspective on the challenges and future research directions for the use of in vivo imaging technology in cancer immunotherapy.

Sindbis Virus Vaccine Platform: A Promising Oncolytic Virus-Mediated Approach for Ovarian Cancer Treatment

This review article provides a comprehensive overview of a novel Sindbis virus vaccine platform as potential immunotherapy for ovarian cancer patients. Ovarian cancer is the most lethal of all gynecological malignancies. The majority of high-grade serous ovarian cancer (HGSOC) patients are diagnosed with advanced disease. Current treatment options are very aggressive and limited, resulting in tumor recurrences and 50-60% patient mortality within 5 years. The unique properties of armed oncolytic Sindbis virus vectors (SV) in vivo have garnered significant interest in recent years to potently target and treat ovarian cancer. We discuss the molecular biology of Sindbis virus, its mechanisms of action against ovarian cancer cells, preclinical in vivo studies, and future perspectives. The potential of Sindbis virus-based therapies for ovarian cancer treatment holds great promise and warrants further investigation. Investigations using other oncolytic viruses in preclinical studies and clinical trials are also presented.

Interleukin-21 as an adjuvant in cancer immunotherapy: Current advances and future directions

Immunotherapy has revolutionized cancer treatment. However, it's well-recognized that a considerable proportion of patients fail to benefit from immunotherapy, and to improve immunotherapy response is clinically urgent. Insufficient immune infiltration and immunosuppressive tumor microenvironments (TME) are main contributors to immunotherapy resistance. Thus sustaining functional self-renewal capacity for immune cells and subverting immune-suppressive signals are potential strategies for boosting the efficacy of immunotherapy. Interleukin-21 (IL-21), a crucial cytokine, which could enhance cytotoxic function of immune cells and reduces immunosuppressive cells enrichment in TME, shows promising orientations as an immunoadjuvant in tumor immunotherapy. This review focuses on IL-21 in cancer treatment, including function and mechanisms of IL-21, preclinical and clinical studies, and future directions for IL-21-assisted therapies.