CCL5-armed oncolytic virus augments CCR5-engineered NK cell infiltration and antitumor efficiency

Non-invasive prediction of DCE-MRI radiomics model on CCR5 in breast cancer based on a machine learning algorithm

BackgroundNon-invasive methods with universal prognostic guidance for detecting breast cancer (BC) survival biomarkers need to be further explored.ObjectiveThis study aimed to investigate C-C motif chemokine receptor type 5 (CCR5) prognosis value in BC and develop a radiomics model for noninvasive prediction of CCR5 expression in BC.MethodsA total of 840 cases with genomic information were included and divided into CCR5 high- and low-expression groups for clinical characteristic differences exploration. Bioinformatics and survival analysis including Kaplan-Meier (KM) survival analysis, Cox regression, immunoinfiltration analysis, and tumor mutation load (TMB) were performed. For radiomics model development, 98 cases with dynamic contrast-enhancement magnetic resonance imaging (DCE-MRI) scans were used. Radiomics features extracted were using Pyradiomics and filtered by maximum-relevance minimum-redundancy (mRMR) and recursive feature elimination (REF) algorithms. Support vector machine (SVM) and logistic regression (LR) models were developed to predict CCR5 expression, with the radiomics score (Rad_score) representing the predicted probability of CCR5 expression. The models' performance was compared using the Delong test, and the model with the superior area under the curve (AUC) values was selected to analyze the correlation between CCR5 expression, Rad_score, and immune genes.ResultsThe CCR5 high-expression group exhibited better overall survival (OS) (p < 0.01). Six radiomics features were selected for model development. The AUCs of the SVM model predicting CCR5 were 0.753 and 0.748 in the training and validation sets, respectively, while the AUCs of the LR model were 0.763 and 0.762. Calibration curves and decision curve analysis (DCA) validated the models' calibration and clinical utility. The SVM_Rad_score showed a strong association with immune-related genes.ConclusionsThe DCE-MRI radiomics model presents a novel, non-invasive tool for predicting CCR5 expression in BC and provides valuable insights to inform clinical decision-making.

Generalization of neoantigen-based tumor vaccine by delivering peptide-MHC complex via oncolytic virus

Neoantigen vaccine is a promising breakthrough in tumor immunotherapy. However, the application of this highly personalized strategy in the treatment of solid tumors is hindered by several obstacles, including very costly and time-consuming preparation steps, uncertainty in prediction algorithms and tumor heterogeneity. Universalization of neoantigen vaccine is an ideal yet currently unattainable solution to such limitations. To overcome these limitations, we engineered oncolytic viruses co-expressing neoantigens and neoantigen-binding major histocompatibility complex (MHC) molecules to force ectopic delivery of peptide-MHC ligands to T cell receptors (TCRs), enabling specific targeting by neoantigen vaccine-primed host immunity. When integrated with neoantigen vaccination, the engineered viruses exhibited potent cytolytic activity in a variety of tumor models irrespective of the neoantigen expression profiles, eliciting robust systemic antitumor immunity to reject tumor rechallenge and inhibit abscopal tumor growth with a favorable safety profile. Thus, this study provides a powerful approach to enhance the universality and efficacy of neoantigen vaccines, meeting the urgent need for universal neoantigen vaccines in the clinic to facilitate the further development of tumor immunotherapy.

Boosting tumor homing of endogenous natural killer cells via therapeutic secretomes of chemically primed natural killer cells

BACKGROUND

Natural killer (NK) cells play a critical role in modulating immune responses by secreting soluble factors, including chemotactic cytokines. Our previous study demonstrated the potent antitumor activity of Chem_NK, referring to NK cells chemically primed with 25 kDa branched polyethyleneimine. However, the potential of Chem_NK secretomes to educate other NK cells and enhance their tumor-homing ability remains unexplored.

METHODS

The effects of Chem_NK conditioned media (Chem CM) on NK cells were evaluated in vitro by examining chemokine receptor expression and migration toward cancer cells. In vivo, the impact of Chem_NK and Chem CM on endogenous NK cell populations was assessed using xenograft and syngeneic mouse tumor models. Cytokine array and signaling analyses were performed to identify factors secreted by Chem_NK and their role in activating recipient NK cells.

RESULTS

Chem CM effectively educated NK cells in vitro, enhancing chemokine receptor expression and improving their migration toward cancer cells. In vivo, adoptively transferred Chem_NK increased endogenous NK cell populations within xenograft tumors. Furthermore, direct injection of Chem CM into a syngeneic mouse tumor model significantly promoted endogenous NK cell infiltration into tumors and suppressed lung metastasis. Cytokine analysis revealed that Chem_NK secreted high levels of cytokines, which activated ERK1/2 signaling in recipient NK cells, leading to upregulation of chemokine receptors.

CONCLUSIONS

Chem_NK secretomes effectively enhance the tumor-homing ability of NK cells and amplify antitumor efficacy by educating other NK cells. These findings offer novel insights into activated NK cell-mediated immune communication and highlight the therapeutic potential of NK cell-derived secretomes in cancer therapy.

Advancing Natural Killer Cell Therapy: Genetic Engineering Strategies for Enhanced Cancer Immunotherapy

Natural killer (NK) cells are pivotal innate immune system components that exhibit spontaneous cytolytic activity against abnormal cells, such as infected and tumor cells. NK cells have shown significant promise in adoptive cell therapy because of their favorable safety profiles and minimal toxicity in clinical settings. Despite their advantages, the therapeutic application of unmodified NK cells faces challenges, including limited in vivo persistence, particularly in the immunosuppressive tumor microenvironment. Recent advances in genetic engineering have enhanced the therapeutic potential of NK cells by addressing these limitations and improving their therapeutic efficacy. In this review, we have described various methodologies for the genetic modification of NK cells, including viral vectors, electroporation, and nanoparticle-based approaches. The ongoing research on nanomaterialbased approaches highlights their potential to overcome current limitations in NK cell therapy, paving the way for advanced cancer therapy and improved clinical outcomes. In this review, we also emphasize the potential of engineered NK cells in cancer immunotherapy and other clinical applications, highlighting the expanding scope of NK cell-based treatments and the critical role of innovative genetic engineering techniques.

Oncolytic Viruses and Immunotherapy for the Treatment of Uveal Melanoma and Retinoblastoma: The Current Landscape and Novel Advances

Intraocular malignant tumors are rare; however, they can cause serious life-threatening complications. Uveal melanoma (UM) and retinoblastoma (RB) are the most common intraocular tumors in adults and children, respectively, and come with a great disease burden. For many years, several different treatment modalities for UM and RB have been proposed, with chemotherapy for RB cases and plaque radiation therapy for localized UM as first-line treatment options. Extraocular extension, recurrence, and metastasis constitute the major challenges of conventional treatments. To overcome these obstacles, immunotherapy, which encompasses different treatment options such as oncolytic viruses, antibody-mediated immune modulations, and targeted immunotherapy, has shown great potential as a novel therapeutic tool for cancer therapy. These anti-cancer treatment options provide numerous advantages such as selective cancer cell death and the promotion of an anti-tumor immune response, and they prove useful in preventing vision impairment due to macular and/or optic disc involvement. Numerous factors such as the vector choice, route of administration, dosing, and patient characteristics must be considered when engineering an oncolytic virus or other forms of immunotherapy vectors. This manuscript provides an in-depth review of the molecular design of oncolytic viruses (e.g., virus capsid proteins and encapsulation technologies, vectors for delivery, cell targeting) and immunotherapy. The most recent advances in preclinical- and clinical-phase studies are further summarized. The recent developments in virus-like drug conjugates (i.e., AU011), oncolytic viruses for metastatic UM, and targeted immunotherapies have shown great results in clinical trials for the future clinical application of these novel technologies in the treatment algorithm of certain intraocular tumors.

Machine learning-derived natural killer cell signature predicts prognosis and therapeutic response in clear cell renal cell carcinoma

BACKGROUND

Natural killer cells, interconnected with patient prognosis and treatment response, play a pivotal role in the tumor immune microenvironment and may serve as potential novel predictive biomarkers for renal cell carcinoma.

METHODS

Clear cell renal cell carcinoma transcriptome data and the corresponding clinical data were obtained from the Cancer Genome Atlas (TCGA) database. Single-cell sequencing data were sourced from the Gene Expression Omnibus (GEO) database. A risk model was established by integrating ten different machine learning algorithms, which resulted in 101 combined models. The model with the highest average C-index was selected for further analysis, and was assessed using nomogram, time-dependent receiver operating characteristics (ROC) and Kaplan-Meier survival analysis. The differences in immune infiltration fractions, clinicopathological features, and response to various targeted therapies and immunotherapy between high- and low-risk groups were investigated. Furthermore, qRT-PCR, IHC, colony formation test, CCK8 assay and flow cytometry were conducted to explore the expression pattern and function of ARHGAP9 in our own patient samples and renal cancer cell lines.

RESULTS

Totally, 156 NK cell-related genes and 5189 prognosis-related genes were identified, and 36 genes of their intersection demonstrated prognostic value. A risk model with 18 genes was established by Coxboost plus plsRcox, which can accurately predict the prognosis of ccRCC patients. Significant correlations were determined between risk score and tumor malignancy and immune cell infiltration. Meanwhile, a combination of tumor mutation burden plus risk score could have higher accuracy of predicting clinical outcomes. Moreover, high-risk group patients were more likely to be responsive to targeted therapy but show no response to immunotherapy.

CONCLUSIONS

Intricate signaling interactions between NK cells and various cellular subgroups were depicted and the developmental trajectory of NK cells was elucidated. A NK cells-related risk model was established, which can provide reliable prognostic information and identified patients with more probability of benefiting from therapy.

Shifting cold to hot tumors by nanoparticle-loaded drugs and products

Cold tumors lack antitumor immunity and are resistant to therapy, representing a major challenge in cancer medicine. Because of the immunosuppressive spirit of the tumor microenvironment (TME), this form of tumor has a low response to immunotherapy, radiotherapy, and also chemotherapy. Cold tumors have low infiltration of immune cells and a high expression of co-inhibitory molecules, such as immune checkpoints and immunosuppressive molecules. Therefore, targeting TME and remodeling immunity in cold tumors can improve the chance of tumor repression after therapy. However, tumor stroma prevents the infiltration of inflammatory cells and hinders the penetration of diverse molecules and drugs. Nanoparticles are an intriguing tool for the delivery of immune modulatory agents and shifting cold to hot tumors. In this review article, we discuss the mechanisms underlying the ability of nanoparticles loaded with different drugs and products to modulate TME and enhance immune cell infiltration. We also focus on newest progresses in the design and development of nanoparticle-based strategies for changing cold to hot tumors. These include the use of nanoparticles for targeted delivery of immunomodulatory agents, such as cytokines, small molecules, and checkpoint inhibitors, and for co-delivery of chemotherapy drugs and immunomodulatory agents. Furthermore, we discuss the potential of nanoparticles for enhancing the efficacy of cancer vaccines and cell therapy for overcoming resistance to treatment.

Potential molecular mechanisms of ETV6-RUNX1-positive B progenitor cell cluster in acute lymphoblastic leukemia revealed by single-cell RNA sequencing

Aim

This study was to explore role of immune landscape and the immune cells in acute lymphoblastic leukemia (ALL) progression.

Background

The most prevalent genetic alteration in childhood ALL is the ETV6-RUNX1 fusion. The increased proliferation of B progenitor cells could expedite the disease's progression due to irregularities in the cell cycle. Nevertheless, the mechanisms by which particular cell clusters influence the cell cycle and promote the advancement of ALL are still not well understood.

Objective

This study was to explore role of immune landscape and the immune cells in ALL progression.

Methods

Single-cell RNA sequencing (scRNA-seq) data of ETV6-RUNX1 and healthy pediatric samples obtained from GSE132509 were clustered and annotated using the Seurat package, and differentially highly expressed genes identified in each cluster were analyzed using DAVID for pathway annotation. Chromosome amplification and deletion were analyzed using the inferCNV package. SCENIC evaluated the regulation of transcription factors and target gene formation in cells. cellphoneDB and CellChat were served to infer ligand-receptor pairs that mediate interactions between subpopulations. The role of the target gene in regulating ALL progression was assessed using RT-qPCR, Transwell and scratch healing assays.

Results

The bone marrow mononuclear cells (BMMCs) from ETV6-RUNX1 and healthy pediatric samples in GSE132509 were divided into 11 clusters, and B cell cluster 1 was identified as B progenitor cell, which was amplified on chromosome 6p. B progenitor cells were divided into seven clusters. Expression levels of amplified genes in chromosome 6p of B progenitor cell cluster 5 were the highest, and its specific highly expressed genes were annotated to pathways promoting cell cycle progression. Regulons formed in B progenitor cell cluster 5 were all involved in promoting cell cycle progression, so it was regarded as the B progenitor cell cluster that drives cell cycle progression. The key regulator of the B progenitor cell is E2F1, which promotes the migration and invasion ability of the cell line HAP1. The major ligand-receptor pairs that mediate the communication of B progenitor cell cluster 5 with cytotoxic NK/T cells or naive T cells included FAM3C-CLEC2D, CD47-SIRPG, HLAE-KLRC2, and CD47-KLRC2. HLAE-KLRC1 and TGFB1-(TGFBR1+TGFBR2).

Conclusion

This study outlined the immune cell landscape of ETV6-RUNX1 ALL and identified chromosome 6p amplification in B progenitor cells, described the major B progenitor cell cluster driving cell cycle progression and its potential regulatory mechanisms on NK cells and T cells, providing cellular and molecular insights into ETV6-RUNX1 ALL.

Decorin-armed oncolytic adenovirus promotes natural killers (NKs) activation and infiltration to enhance NK therapy in CRC model

Colorectal cancer (CRC) is a prevalent malignant tumor of the gastrointestinal system, with the third and second highest incidence and mortality rates globally in 2020, respectively. Immunotherapy has developed rapidly in recent years. Natural killer (NK) cells have received increasing attention in the field of tumor immunotherapy due to their recognition and killing tumor cells without the limitations of major histocompatibility complexes. However, constraints within the tumor microenvironment that impede the infiltration and proliferation of NK cells result in poor efficacy of NK cell therapy for solid tumors. Oncolytic viral therapy is an immunogenic treatment with the potential to enhance anti-tumour immune responses and promote immune cell infiltration. In this study, we synergistically combine NK cells with an oncolytic adenovirus carrying Decorin (rAd.DCN) for the treatment of colorectal cancer (CRC) in a xenograft mouse model. By using Flow cytometry, real-time quantitative PCR and Calcein-AM release assay, we found that rAd.DCN could effectively promote proliferation, activation and degranulation of NK cells, up-regulate expression and secretion of NK cell killing activity-related factors, and enhance their killing activity. The efficacy is better than that of the blank control oncolytic virus rAd.Null. Combined treatment significantly inhibited tumor growth, increased the number of NK cells in peripheral blood, promoted the killing function of NK cells, and increased the expression levels of perforin and IFN-γ. At the same time, more NK cells were recruited to infiltrate tumor tissue. Our study established the feasibility of combination NK cells and oncolytic adenovirus application, thus expanding the scope of potentially curative treatments for NK cells in CRC.

Oncolytic Viruses as Reliable Adjuvants in CAR-T Cell Therapy for Solid Tumors

Although impactful scientific advancements have recently been made in cancer therapy, there remains an opportunity for future improvements. Immunotherapy is perhaps one of the most cutting-edge categories of therapies demonstrating potential in the clinical setting. Genetically engineered T cells express chimeric antigen receptors (CARs), which can detect signals expressed by the molecules present on the surface of cancer cells, also called tumor-associated antigens (TAAs). Their effectiveness has been extensively demonstrated in hematological cancers; therefore, these results can establish the groundwork for their applications on a wide range of requirements. However, the application of CAR-T cell technology for solid tumors has several challenges, such as the existence of an immune-suppressing tumor microenvironment and/or inadequate tumor infiltration. Consequently, combining therapies such as CAR-T cell technology with other approaches has been proposed. The effectiveness of combining CAR-T cell with oncolytic virus therapy, with either genetically altered or naturally occurring viruses, to target tumor cells is currently under investigation, with several clinical trials being conducted. This narrative review summarizes the current advancements, opportunities, benefits, and limitations in using each therapy alone and their combination. The use of oncolytic viruses offers an opportunity to address the existing challenges of CAR-T cell therapy, which appear in the process of trying to overcome solid tumors, through the combination of their strengths. Additionally, utilizing oncolytic viruses allows researchers to modify the virus, thus enabling the targeted delivery of specific therapeutic agents within the tumor environment. This, in turn, can potentially enhance the cytotoxic effect and therapeutic potential of CAR-T cell technology on solid malignancies, with impactful results in the clinical setting.

Chemokines in the tumor microenvironment: implications for lung cancer and immunotherapy

The tumor microenvironment (TME) is a complex interconnected network of immune cells, fibroblasts, blood vessels, and extracellular matrix surrounding the tumor. Because of its immunosuppressive nature, the TME can pose a challenge for cancer immunotherapies targeting solid tumors. Chemokines have emerged as a crucial element in enhancing the efficacy of cancer immunotherapy, playing a direct role in immune cell signaling within the TME and facilitating immune cell migration towards cancer cells. However, chemokine ligands and their receptors exhibit context-dependent diversity, necessitating evaluation of their tumor-promoting or inhibitory effects based on tumor type and immune cell characteristics. This review explores the role of chemokines in tumor immunity and metastasis in the context of the TME. We also discuss current chemokine-related advances in cancer immunotherapy research, with a particular focus on lung cancer, a common cancer with a low survival rate and limited immunotherapy options.

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.

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.

The combination therapy of oncolytic virotherapy

Introduction: Compared to other cancer immunotherapies, oncolytic viruses possess several advantages, including high killing efficiency, excellent targeting capabilities, minimal adverse reactions, and multiple pathways for tumor destruction. However, the efficacy of oncolytic viruses as a monotherapy often falls short of expectations. Consequently, combining oncolytic viruses with traditional treatments to achieve synergistic effects has emerged as a promising direction for the development of oncolytic virus therapies. Methods: This article provides a comprehensive review of the current progress in preclinical and clinical trials exploring the combination therapies involving oncolytic viruses. Results: Specifically, we discuss the combination of oncolytic viruses with immune checkpoint inhibitors, chemotherapy, targeted therapy, and cellular therapy. Discussion: The aim of this review is to offer valuable insights and references for the further advancement of these combination strategies in clinical applications. Further research is necessary to refine the design of combination therapies and explore novel strategies to maximize the therapeutic benefits offered by oncolytic viruses.

Enhanced cellular therapy: revolutionizing adoptive cellular therapy

Enhanced cellular therapy has emerged as a novel concept following the basis of cellular therapy. This treatment modality applied drugs or biotechnology to directly enhance or genetically modify cells to enhance the efficacy of adoptive cellular therapy (ACT). Drugs or biotechnology that enhance the killing ability of immune cells include immune checkpoint inhibitors (ICIs) / antibody drugs, small molecule inhibitors, immunomodulatory factors, proteolysis targeting chimera (PROTAC), oncolytic virus (OV), etc. Firstly, overcoming the inhibitory tumor microenvironment (TME) can enhance the efficacy of ACT, which can be achieved by blocking the immune checkpoint. Secondly, cytokines or cytokine receptors can be expressed by genetic engineering or added directly to adoptive cells to enhance the migration and infiltration of adoptive cells to tumor cells. Moreover, multi-antigen chimeric antigen receptors (CARs) can be designed to enhance the specific recognition of tumor cell-related antigens, and OVs can also stimulate antigen release. In addition to inserting suicide genes into adoptive cells, PROTAC technology can be used as a safety switch or degradation agent of immunosuppressive factors to enhance the safety and efficacy of adoptive cells. This article comprehensively summarizes the mechanism, current situation, and clinical application of enhanced cellular therapy, describing potential improvements to adoptive cellular therapy.

Molecular Circuits of Immune Sensing and Response to Oncolytic Virotherapy

Oncolytic virotherapy is a promising immunotherapy approach for cancer treatment that utilizes viruses to preferentially infect and eliminate cancer cells while stimulating the immune response. In this review, we synthesize the current literature on the molecular circuits of immune sensing and response to oncolytic virotherapy, focusing on viral DNA or RNA sensing by infected cells, cytokine and danger-associated-signal sensing by neighboring cells, and the subsequent downstream activation of immune pathways. These sequential sense-and-response mechanisms involve the triggering of molecular sensors by viruses or infected cells to activate transcription factors and related genes for a breadth of immune responses. We describe how the molecular signals induced in the tumor upon virotherapy can trigger diverse immune signaling pathways, activating both antigen-presenting-cell-based innate and T cell-based adaptive immune responses. Insights into these complex mechanisms provide valuable knowledge for enhancing oncolytic virotherapy strategies.

Development of NK cell-based cancer immunotherapies through receptor engineering

Natural killer (NK) cell-based immunotherapies are attracting increasing interest in the field of cancer treatment. Early clinical trials have shown promising outcomes, alongside satisfactory product efficacy and safety. Recent developments have greatly increased the therapeutic potential of NK cells by endowing them with enhanced recognition and cytotoxic capacities. This review focuses on surface receptor engineering in NK cell therapy and discusses its impact, challenges, and future directions.Most approaches are based on engineering with chimeric antigen receptors to allow NK cells to target specific tumor antigens independent of human leukocyte antigen restriction. This approach has increased the precision and potency of NK-mediated recognition and elimination of cancer cells. In addition, engineering NK cells with T-cell receptors also mediates the recognition of intracellular epitopes, which broadens the range of target peptides. Indirect tumor peptide recognition by NK cells has also been improved by optimizing immunoglobulin constant fragment receptor expression and signaling. Indeed, engineered NK cells have an improved ability to recognize and destroy target cells coated with specific antibodies, thereby increasing their antibody-dependent cellular cytotoxicity. The ability of NK cell receptor engineering to promote the expansion, persistence, and infiltration of transferred cells in the tumor microenvironment has also been explored. Receptor-based strategies for sustained NK cell functionality within the tumor environment have also been discussed, and these strategies providing perspectives to counteract tumor-induced immunosuppression.Overall, receptor engineering has led to significant advances in NK cell-based cancer immunotherapies. As technical challenges are addressed, these innovative treatments will likely reshape cancer immunotherapy.

Empowering pancreatic tumor homing with augmented anti-tumor potency of CXCR2-tethered CAR-NK cells

Chimeric antigen receptor (CAR)-engineered natural killer (NK) cells are a promising immunotherapy for solid cancers; however, their effectiveness against pancreatic cancer is limited by the immunosuppressive tumor microenvironment. In particular, low NK cell infiltration poses a major obstacle that reduces cytotoxicity. The current study aimed to enhance the tumor-homing capacity of CAR-NK cells by targeting the chemokine-chemokine receptor axis between NK and pancreatic cancer cells. To this end, data from a chemokine array and The Cancer Genome Atlas pan-cancer cohort were analyzed. Pancreatic cancer cells were found to secrete high levels of ligands for C-X-C motif receptor 1 (CXCR1) and CXCR2. Subsequently, we generated anti-mesothelin CAR-NK cells incorporating CXCR1 or CXCR2 and evaluated their tumor-killing abilities in 2D cancer cell co-culture and 3D tumor-mimetic organoid models. CAR-NK cells engineered with CXCR2 demonstrated enhanced tumor killing and strong infiltration of tumor sites. Collectively, these findings highlight the potential of CXCR2-augmented CAR-NK cells as a clinically relevant modality for effective pancreatic cancer treatment. By improving their infiltration and tumor-killing capabilities, these CXCR2-augmented CAR-NK cells have the potential to overcome the challenges posed by the immunosuppressive tumor microenvironment, providing improved therapeutic outcomes.

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.

Expression of GPX4 by oncolytic vaccinia virus can significantly enhance CD8+T cell function and its impact against pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is currently difficult to treat, even when therapies are combined with immune checkpoint blockade (ICB). A novel strategy for immunotherapy would be to maximize the therapeutic potential of oncolytic viruses (OVs), which have been proven to engage the regulation of tumor microenvironment (TME) and cause-specific T-cell responses. To boost tumor sensitivity to ICB therapy, this study aimed to investigate how glutathione peroxide 4 (GPX4)-loaded OVs affect CD8+ T cells and repair the immunosuppressive environment. Here, we successfully constructed a novel recombinant oncolytic vaccinia virus (OVV) encoding the mouse GPX4 gene. We found the OVV-GPX4 effectively replicated in tumor cells and prompted the expression of GPX4 in T cells. Our research indicated that OVV-GPX4 could reshape the TME, rectify the depletion of CD8+T cells, and enhance the antitumor effects of ICB therapy.

Real-time ex vivo monitoring of NK cell migration toward obesity-associated oesophageal adenocarcinoma following modulation of CX3CR1

Oesophagogastric adenocarcinomas (OAC) are poor prognosis, obesity-associated cancers which may benefit from natural killer (NK) cell-based immunotherapies. Cellular immunotherapies encounter two key challenges to their success in OAC, namely recruitment to extratumoural tissues such as the omentum at the expense of the tumour and an immunosuppressive tumour microenvironment (TME) which can hamper NK cell function. Herein, we examined approaches to overcome the detrimental impact of obesity on NK cells and NK cell-based immunotherapies. We have demonstrated that NK cells migrate preferentially to the chemotactic signals of OAC patient-derived omentum over tumour in an ex vivo model of immune cell migration. We have identified CX3CR1 modulation and/or tumour chemokine profile remodelling as approaches to skew NK cell migration towards tumour. We also report targetable immunosuppressive facets of the obese OAC TME which dampen NK cell function, in particular cytotoxic capabilities. These data provide insights into approaches to therapeutically overcome key challenges presented by obesity and will inform superior design of NK cell-based immunotherapies for OAC.

Interleukin-10 gene intervention ameliorates liver fibrosis by enhancing the immune function of natural killer cells in liver tissue

BACKGROUND AND AIMS

Interleukin 10 (IL-10) and natural killer (NK) cells have the potential to combat liver fibrosis. However, whether NK cells play an important role in the anti-fibrotic effects of IL-10 is not sufficiently elucidated. In this study, we investigated the regulatory effects of IL-10 on NK cells during liver fibrosis.

METHODS

Fibrotic mice induced with carbon tetrachloride were treated with or without IL-10 in the presence or absence of NK cells. Liver damage and fibrosis were assessed using hematoxylin and eosin and Sirius Red staining and serum transaminase and liver hydroxyproline assays, respectively. NK cell distribution, quantity, activation, cytotoxicity, development, and origin were analyzed using immunohistochemistry, immunofluorescence, and flow cytometry. Enzyme-linked immunosorbent assay was used to determine chemokine levels.

RESULTS

In the presence of NK cells, IL-10 gene intervention improved liver fibrosis and enhanced NK cell accumulation and function in the liver, as evidenced by increased NKG2D, interferon-γ, and CD107a expression. Furthermore, IL-10 promoted the migration of circulating NK cells to the fibrotic liver and elevated C-C motif ligand 5 levels. However, depletion of NK cells exacerbated liver fibrosis and impaired the anti-fibrotic effect of IL-10.

CONCLUSIONS

The anti-fibrotic effect of IL-10 relies on the enhancement of NK cell immune function, including activation, cytotoxicity, development, and migration. These results provide valuable insights into the mechanisms through which IL-10 regulates NK cells to limit the progression of liver fibrosis.

Oncolytic viral therapy as promising immunotherapy against glioma

Glioma is a common primary central nervous system malignant tumor in clinical, traditional methods such as surgery and chemoradiotherapy are not effective in treatment. Therefore, more effective treatments need to be found. Oncolytic viruses (OVs) are a new type of immunotherapy that selectively infects and kills tumor cells instead of normal cells. OVs can mediate antitumor immune responses through a variety of mechanisms, and have the ability to activate antitumor immune responses, transform the tumor microenvironment from “cold” to “hot,” and enhance the efficacy of immune checkpoint inhibitors. Recently, a large number of preclinical and clinical studies have shown that OVs show great prospects in the treatment of gliomas. In this review, we summarize the current status of glioma therapies with a focus on OVs. First, this article introduces the current status of treatment of glioma and their respective shortcomings. Then, the important progress of OVs of in clinical trials of glioma is summarized. Finally, the urgent challenges of oncolytic virus treatment for glioma are sorted out, and related solutions are proposed. This review will help to further promote the use of OVs in the treatment of glioma.

Advancements and challenges in oncolytic virus therapy for gastrointestinal tumors

BACKGROUND

Tumors of the gastrointestinal tract impose a substantial healthcare burden due to their prevalence and challenging prognosis.

METHODS

We conducted a review of peer-reviewed scientific literature using reputable databases (PubMed, Scopus, Web of Science) with a focus on oncolytic virus therapy within the context of gastrointestinal tumors. Our search covered the period up to the study's completion in June 2023.

INCLUSION AND EXCLUSION CRITERIA

This study includes articles from peer-reviewed scientific journals, written in English, that specifically address oncolytic virus therapy for gastrointestinal tumors, encompassing genetic engineering advances, combined therapeutic strategies, and safety and efficacy concerns. Excluded are articles not meeting these criteria or focusing on non-primary gastrointestinal metastatic tumors.

RESULTS

Our review revealed the remarkable specificity of oncolytic viruses in targeting tumor cells and their potential to enhance anti-tumor immune responses. However, challenges related to safety and efficacy persist, underscoring the need for ongoing research and improvement.

CONCLUSION

This study highlights the promising role of oncolytic virus therapy in enhancing gastrointestinal tumor treatments. Continued investigation and innovative combination therapies hold the key to reducing the burden of these tumors on patients and healthcare systems.

Charting a killer course to the solid tumor: strategies to recruit and activate NK cells in the tumor microenvironment

The ability to expand and activate natural Killer (NK) cells ex vivo has dramatically changed the landscape in the development of novel adoptive cell therapies for treating cancer over the last decade. NK cells have become a key player for cancer immunotherapy due to their innate ability to kill malignant cells while not harming healthy cells, allowing their potential use as an "off-the-shelf" product. Furthermore, recent advancements in NK cell genetic engineering methods have enabled the efficient generation of chimeric antigen receptor (CAR)-expressing NK cells that can exert both CAR-dependent and antigen-independent killing. Clinically, CAR-NK cells have shown promising efficacy and safety for treating CD19-expressing hematologic malignancies. While the number of pre-clinical studies using CAR-NK cells continues to expand, it is evident that solid tumors pose a unique challenge to NK cell-based adoptive cell therapies. Major barriers for efficacy include low NK cell trafficking and infiltration into solid tumor sites, low persistence, and immunosuppression by the harsh solid tumor microenvironment (TME). In this review we discuss the barriers posed by the solid tumor that prevent immune cell trafficking and NK cell effector functions. We then discuss promising strategies to enhance NK cell infiltration into solid tumor sites and activation within the TME. This includes NK cell-intrinsic and -extrinsic mechanisms such as NK cell engineering to resist TME-mediated inhibition and use of tumor-targeted agents such as oncolytic viruses expressing chemoattracting and activating payloads. We then discuss opportunities and challenges for using combination therapies to extend NK cell therapies for the treatment of solid tumors.

Balancing act: the complex role of NK cells in immune regulation

Natural killer (NK) cells, as fundamental components of innate immunity, can quickly react to abnormalities within the body. In-depth research has revealed that NK cells possess regulatory functions not only in innate immunity but also in adaptive immunity under various conditions. Multiple aspects of the adaptive immune process are regulated through NK cells. In our review, we have integrated multiple studies to illuminate the regulatory function of NK cells in regulating B cell and T cell responses during adaptive immune processes, focusing on aspects including viral infections and the tumor microenvironment (TME). These insights provide us with many new understandings on how NK cells regulate different phases of the adaptive immune response.

Inactivation of the DNA-sensing pathway facilitates oncolytic herpes simplex virus inhibition of pancreatic ductal adenocarcinoma growth

Oncolytic viruses are a new class of therapeutic agents for the treatment of cancer that have shown promising results in clinical trials. Oncolytic virus-mediated tumor rejection is highly dependent on viral replication in tumor cells to induce cell death. However, the antiviral immune response of tumor cells limits the replication capacity of oncolytic viruses. We hypothesized that inhibition of the antiviral immune response in infected cells would enhance the antitumor effect. Here, we confirmed that ablation of the key adaptor protein of cellular immunity, STING, significantly suppressed the antiviral immune response and promoted oncolytic herpes simplex virus-1 (oHSV1) proliferation in tumor cells. In a murine pancreatic ductal adenocarcinoma (PDAC) model, oHSV1 enhanced tumor suppression and prolonged the survival of mice in the absence of STING. On this basis, we further found that the TBK1 inhibitor can also significantly enhance the tumor-control ability of oHSV1. Our studies provide a novel strategy for oncolytic virus therapy by inhibiting the intrinsic antiviral response in solid tumors to improve antitumor efficacy.

[Oncolytic viruses: Actors and deliverers of therapeutic proteins against tumors]

The discovery of the unique ability of certain viruses to specifically target cancer cells has led to significant advancements in cancer immunotherapy research. In addition to inducing specific lysis of cancer cells, oncolytic viruses (OV) have been genetically modified to express molecules of interest within the tumor bed. The use of OV as vectors for therapeutic molecules has allowed to enhance antitumor responses while limiting the adverse effects associated with systemic administration of the molecule. Other studies are currently focused on delaying the neutralization and clearance of the virus by the host's immune system and improving its delivery insight tumors.

Harnessing Natural Killer Cells for Lung Cancer Therapy

Lung cancer is the leading cause of cancer-related death worldwide. Although natural killer (NK) cells are garnering interest as a potential anticancer therapy because they selectively recognize and eliminate cancer cells, their use in treating solid tumors, including lung cancer, has been limited due to impediments to their efficacy, such as their limited ability to reach tumor tissues, the reduced antitumor activity of tumor-infiltrating NK cells, and the suppressive tumor microenvironment (TME). This comprehensive review provides an in-depth analysis of the cross-talk between the lung cancer TME and NK cells. We highlight the various mechanisms used by the TME to modulate NK-cell phenotypes and limit infiltration, explore the role of the TME in limiting the antitumor activity of NK cells, and discuss the current challenges and obstacles that hinder the success of NK-cell-based immunotherapy for lung cancer. Potential opportunities and promising strategies to address these challenges have been implemented or are being developed to optimize NK-cell-based immunotherapy for lung cancer. Through critical evaluation of existing literature and emerging trends, this review provides a comprehensive outlook on the future of NK-cell-based immunotherapy for treating lung cancer.

Personalizing Oncolytic Virotherapy

The use of oncolytic viruses has become an attractive tool in the clinics for the treatment of various tumor types. Such viruses are genetically modified to conditionally replicate in malignant cells while unharming healthy cells. This platform offers a highly specific tumor killing with exceptional safety profiles. However, the use of oncolytic viruses as sole oncolytic platforms has not achieved full tumor clearance in murine models and in the clinics. In fact, the formation of anti-tumor immune responses is attributed to the effectiveness of oncolytic viruses. In this review, we will discuss the various strategies that scientists have employed to enhance the anti-tumor immune responses driven by oncolytic viruses. Moreover, focus will be drawn into personalizing such anti-tumor responses by the addition of tumor-associated peptides.

Preclinical and clinical trials of oncolytic vaccinia virus in cancer immunotherapy: a comprehensive review

Oncolytic virotherapy has emerged as a promising treatment for human cancers owing to an ability to elicit curative effects via systemic administration. Tumor cells often create an unfavorable immunosuppressive microenvironment that degrade viral structures and impede viral replication; however, recent studies have established that viruses altered via genetic modifications can serve as effective oncolytic agents to combat hostile tumor environments. Specifically, oncolytic vaccinia virus (OVV) has gained popularity owing to its safety, potential for systemic delivery, and large gene insertion capacity. This review highlights current research on the use of engineered mutated viruses and gene-armed OVVs to reverse the tumor microenvironment and enhance antitumor activity in vitro and in vivo, and provides an overview of ongoing clinical trials and combination therapies. In addition, we discuss the potential benefits and drawbacks of OVV as a cancer therapy, and explore different perspectives in this field.

Oncolytic Virus Engineering and Utilizations: Cancer Immunotherapy Perspective

Oncolytic viruses have positively impacted cancer immunotherapy over the past 20 years. Both natural and genetically modified viruses have shown promising results in treating various cancers. Various regulatory authorities worldwide have approved four commercial oncolytic viruses, and more are being developed to overcome this limitation and obtain better anti-tumor responses in clinical trials at various stages. Faster advancements in translating research into the commercialization of cancer immunotherapy and a comprehensive understanding of the modification strategies will widen the current knowledge of future technologies related to the development of oncolytic viruses. In this review, we discuss the strategies of virus engineering and the progress of clinical trials to achieve virotherapeutics.

Site-specific transgene integration in chimeric antigen receptor (CAR) T cell therapies

Chimeric antigen receptor (CAR) T cells and natural killer (NK) cells are genetically engineered immune cells that can detect target antigens on the surface of target cells and eliminate them following adoptive transfer. Recent progress in CAR-based therapies has led to outstanding clinical success in certain patients with leukemias and lymphomas and offered therapeutic benefits to those resistant to conventional therapies. The universal approach to stable CAR transgene delivery into the T/NK cells is the use of viral particles. Such approaches mediate semi-random transgene insertions spanning the entire genome with a high preference for integration into sites surrounding highly-expressed genes and active loci. Regardless of the variable CAR expression level based on the integration site of the CAR transgene, foreign integrated DNA fragments may affect the neighboring endogenous genes and chromatin structure and potentially change a transduced T/NK cell behavior and function or even favor cellular transformation. In contrast, site-specific integration of CAR constructs using recent genome-editing technologies could overcome the limitations and disadvantages of universal random gene integration. Herein, we explain random and site-specific integration of CAR transgenes in CAR-T/NK cell therapies. Also, we tend to summarize the methods for site-specific integration as well as the clinical outcomes of certain gene disruptions or enhancements due to CAR transgene integration. Also, the advantages and limitations of using site-specific integration methods are discussed in this review. Ultimately, we will introduce the genomic safe harbor (GSH) standards and suggest some appropriate safety prospects for CAR integration in CAR-T/NK cell therapies.

Site-specific transgene integration in chimeric antigen receptor (CAR) T cell therapies

Chimeric antigen receptor (CAR) T cells and natural killer (NK) cells are genetically engineered immune cells that can detect target antigens on the surface of target cells and eliminate them following adoptive transfer. Recent progress in CAR-based therapies has led to outstanding clinical success in certain patients with leukemias and lymphomas and offered therapeutic benefits to those resistant to conventional therapies. The universal approach to stable CAR transgene delivery into the T/NK cells is the use of viral particles. Such approaches mediate semi-random transgene insertions spanning the entire genome with a high preference for integration into sites surrounding highly-expressed genes and active loci. Regardless of the variable CAR expression level based on the integration site of the CAR transgene, foreign integrated DNA fragments may affect the neighboring endogenous genes and chromatin structure and potentially change a transduced T/NK cell behavior and function or even favor cellular transformation. In contrast, site-specific integration of CAR constructs using recent genome-editing technologies could overcome the limitations and disadvantages of universal random gene integration. Herein, we explain random and site-specific integration of CAR transgenes in CAR-T/NK cell therapies. Also, we tend to summarize the methods for site-specific integration as well as the clinical outcomes of certain gene disruptions or enhancements due to CAR transgene integration. Also, the advantages and limitations of using site-specific integration methods are discussed in this review. Ultimately, we will introduce the genomic safe harbor (GSH) standards and suggest some appropriate safety prospects for CAR integration in CAR-T/NK cell therapies.

Opportunities and challenges of combining adoptive cellular therapy with oncolytic virotherapy

The use of oncolytic viruses (OVs) and adoptive cell therapies (ACT) have independently emerged as promising approaches for cancer immunotherapy. More recently, the combination of such agents to obtain a synergistic anticancer effect has gained attention, particularly in solid tumors, where immune-suppressive barriers of the microenvironment remain a challenge for desirable therapeutic efficacy. While adoptive cell monotherapies may be restricted by an immunologically cold or suppressive tumor microenvironment (TME), OVs can serve to prime the TME by eliciting a wave of cancer-specific immunogenic cell death and inducing enhanced antitumor immunity. While OV/ACT synergy is an attractive approach, immune-suppressive barriers remain, and methods should be considered to optimize approaches for such combination therapy. In this review, we summarize current approaches that aim to overcome these barriers to enable optimal synergistic antitumor effects.

Recombinant Strains of Oncolytic Vaccinia Virus for Cancer Immunotherapy

Cancer virotherapy is an alternative therapeutic approach based on the viruses that selectively infect and kill tumor cells. Vaccinia virus (VV) is a member of the Poxviridae, a family of enveloped viruses with a large linear double-stranded DNA genome. The proven safety of the VV strains as well as considerable transgene capacity of the viral genome, make VV an excellent platform for creating recombinant oncolytic viruses for cancer therapy. Furthermore, various genetic modifications can increase tumor selectivity and therapeutic efficacy of VV by arming it with the immune-modulatory genes or proapoptotic molecules, boosting the host immune system, and increasing cross-priming recognition of the tumor cells by T-cells or NK cells. In this review, we summarized the data on bioengineering approaches to develop recombinant VV strains for enhanced cancer immunotherapy.

Advancements in CAR-NK therapy: lessons to be learned from CAR-T therapy

Advancements in chimeric antigen receptor engineered T-cell (CAR-T) therapy have revolutionized treatment for several cancer types over the past decade. Despite this success, obstacles including the high price tag, manufacturing complexity, and treatment-associated toxicities have limited the broad application of this therapy. Chimeric antigen receptor engineered natural killer cell (CAR-NK) therapy offers a potential opportunity for a simpler and more affordable "off-the-shelf" treatment, likely with fewer toxicities. Unlike CAR-T, CAR-NK therapies are still in early development, with few clinical trials yet reported. Given the challenges experienced through the development of CAR-T therapies, this review explores what lessons we can apply to build better CAR-NK therapies. In particular, we explore the importance of optimizing the immunochemical properties of the CAR construct, understanding factors leading to cell product persistence, enhancing trafficking of transferred cells to the tumor, ensuring the metabolic fitness of the transferred product, and strategies to avoid tumor escape through antigen loss. We also review trogocytosis, an important emerging challenge that likely equally applies to CAR-T and CAR-NK cells. Finally, we discuss how these limitations are already being addressed in CAR-NK therapies, and what future directions may be possible.

Oncolytic virotherapy: basic principles, recent advances and future directions

Oncolytic viruses (OVs) have attracted growing awareness in the twenty-first century, as they are generally considered to have direct oncolysis and cancer immune effects. With the progress in genetic engineering technology, OVs have been adopted as versatile platforms for developing novel antitumor strategies, used alone or in combination with other therapies. Recent studies have yielded eye-catching results that delineate the promising clinical outcomes that OVs would bring about in the future. In this review, we summarized the basic principles of OVs in terms of their classifications, as well as the recent advances in OV-modification strategies based on their characteristics, biofunctions, and cancer hallmarks. Candidate OVs are expected to be designed as "qualified soldiers" first by improving target fidelity and safety, and then equipped with "cold weapons" for a proper cytocidal effect, "hot weapons" capable of activating cancer immunotherapy, or "auxiliary weapons" by harnessing tactics such as anti-angiogenesis, reversed metabolic reprogramming and decomposing extracellular matrix around tumors. Combinations with other cancer therapeutic agents have also been elaborated to show encouraging antitumor effects. Robust results from clinical trials using OV as a treatment congruously suggested its significance in future application directions and challenges in developing OVs as novel weapons for tactical decisions in cancer treatment.

Improving poxvirus-mediated antitumor immune responses by deleting viral cGAMP-specific nuclease

cGAMP-specific nucleases (poxins) are a recently described family of proteins dedicated to obstructing cyclic GMP-AMP synthase signaling (cGAS), an important sensor triggered by cytoplasmic viral replication that activates type I interferon (IFN) production. The B2R gene of vaccinia viruses (VACV) codes for one of these nucleases. Here, we evaluated the effects of inactivating the VACV B2 nuclease in the context of an oncolytic VACV. VACV are widely used as anti-cancer vectors due to their capacity to activate immune responses directed against tumor antigens. We aimed to elicit robust antitumor immunity by preventing viral inactivation of the cGAS/STING/IRF3 pathway after infection of cancer cells. Activation of such a pathway is associated with a dominant T helper 1 (Th1) cell differentiation of the response, which benefits antitumor outcomes. Deletion of the B2R gene resulted in enhanced IRF3 phosphorylation and type I IFN expression after infection of tumor cells, while effective VACV replication remained unimpaired, both in vitro and in vivo. In syngeneic mouse tumor models, the absence of the VACV cGAMP-specific nuclease translated into improved antitumor activity, which was associated with antitumor immunity directed against tumor epitopes.

Efficient Redirection of NK Cells by Genetic Modification with Chemokine Receptors CCR4 and CCR2B

Natural killer (NK) cells are a subset of lymphocytes that offer great potential for cancer immunotherapy due to their natural anti-tumor activity and the possibility to safely transplant cells from healthy donors to patients in a clinical setting. However, the efficacy of cell-based immunotherapies using both T and NK cells is often limited by a poor infiltration of immune cells into solid tumors. Importantly, regulatory immune cell subsets are frequently recruited to tumor sites. In this study, we overexpressed two chemokine receptors, CCR4 and CCR2B, that are naturally found on T regulatory cells and tumor-resident monocytes, respectively, on NK cells. Using the NK cell line NK-92 as well as primary NK cells from peripheral blood, we show that genetically engineered NK cells can be efficiently redirected using chemokine receptors from different immune cell lineages and migrate towards chemokines such as CCL22 or CCL2, without impairing the natural effector functions. This approach has the potential to enhance the therapeutic effect of immunotherapies in solid tumors by directing genetically engineered donor NK cells to tumor sites. As a future therapeutic option, the natural anti-tumor activity of NK cells at the tumor sites can be increased by co-expression of chemokine receptors with chimeric antigen receptors (CAR) or T cell receptors (TCR) on NK cells can be performed in the future.

Combining of Oncolytic Virotherapy and Other Immunotherapeutic Approaches in Cancer: A Powerful Functionalization Tactic

Oncolytic viruses have found a good place in the treatment of cancer. Administering oncolytic viruses directly or by applying genetic changes can be effective in cancer treatment through the lysis of tumor cells and, in some cases, by inducing immune system responses. Moreover, oncolytic viruses induce antitumor immune responses via releasing tumor antigens in the tumor microenvironment (TME) and affect tumor cell growth and metabolism. Despite the success of virotherapy in cancer therapies, there are several challenges and limitations, such as immunosuppressive TME, lack of effective penetration into tumor tissue, low efficiency in hypoxia, antiviral immune responses, and off-targeting. Evidence suggests that oncolytic viruses combined with cancer immunotherapy-based methods such as immune checkpoint inhibitors and adoptive cell therapies can effectively overcome these challenges. This review summarizes the latest data on the use of oncolytic viruses for the treatment of cancer and the challenges of this method. Additionally, the effectiveness of mono, dual, and triple therapies using oncolytic viruses and other anticancer agents has been discussed based on the latest findings.

Harnessing natural killer cells to develop next-generation cellular immunotherapy

Cellular immunotherapy harnesses the body's own immune system to fight cancer by using engineered T cells, macrophages, or natural killer (NK) cells. Compared to chimeric antigen receptor T (CAR-T) cells that are commonly used to treat hematological malignancies, CAR-NK cells have shown remarkable therapeutic effectiveness while exhibiting enhanced safety, reduced risk of graft-versus-host disease, fewer side effects, and amplified antitumor efficacy. Preclinical trials have unveiled the high potential of adoptive CAR-NK cell therapy to curtail or even eliminate both hematological malignancies and solid tumors in animal models. We brought forth herein the design principle of CAR-NK cells, highlighted the latest progress in the preclinical testing and clinical trials of CAR-NK cells, briefly delved into discussed major roadblocks in CAR-NK therapy, and discussed potential solutions to surmount these challenges. Given the accelerated progress in both basic and translational studies on immune cell engineering, CAR-NK cell therapy promises to become a serious contender and important addition to the next-generation cell-based immunotherapy.

Combination cancer immunotherapies: Emerging treatment strategies adapted to the tumor microenvironment

Immune checkpoint blockade (ICB) has revolutionized cancer treatment. However, resistance to ICB occurs frequently due to tumor-intrinsic alterations or extrinsic factors in the tumor microenvironment. This Viewpoint aims to give an update on recent developments in immunotherapy for solid tumors and highlights progress in translational research and clinical practice.

Current landscape and perspective of oncolytic viruses and their combination therapies

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Oncolytic virotherapy has become an important branch of cancer immunotherapy in clinical practice.

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Multiple viruses can be engineered to be OVs and armed with anticancer genes to enhance their efficacy.

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OVs can reshape TME and produce synergistic anticancer efficacy when combined with other therapies.

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Safety and effectiveness are the main direction of future research and development of OVs.

Oncolytic virotherapy has become an important strategy in cancer immunotherapy. Oncolytic virus (OV) can reshape the tumor microenvironment (TME) through its replication-mediated oncolysis and transgene-produced anticancer effect, inducing an antitumor immune response and creating favorable conditions for the combination of other therapeutic measures. Extensive preclinical and clinical data have suggested that OV-based combination therapy has definite efficacy and promising prospects. Recently, several clinical trials of oncolytic virotherapy combined with immunotherapy have made breakthroughs. This review comprehensively elaborates the OV types and their targeting mechanisms, the selection of anticancer genes armed in OVs, and the therapeutic modes of action and strategies of OVs to provide a theoretical basis for the better design and construction of OVs and the optimization of OV-based therapeutic strategies.

Single-cell transcriptome profiling reveals the key role of ZNF683 in natural killer cell exhaustion in multiple myeloma

BACKGROUNDS

Decreased cytotoxicity of natural killer (NK) cells has been shown in multiple myeloma (MM). However, the underlying molecular mechanisms remain unclear. Here, by using single-cell RNA sequencing analysis and in vitro experiments, we aim to uncover and validate molecularly distinctive insights into identifying regulators for NK cell exhaustion and provide potential targets for novel immune therapies in MM.

METHODS

Single-cell RNA sequencing was conducted in the bone marrow and peripheral blood samples from 10 newly diagnosed MM patients and three healthy volunteers. Based on the cluster-defining differentially expressed genes, we named and estimated functional states of each cluster via bioinformatics analyses. Functional significance of key findings obtained from sequencing analysis was examined in a series of in vitro experiments, including luciferase reporter assay, lentiviral expression vector construction, NK cell transfection, RT-qPCR, flow cytometry, and cytotoxicity assay.

RESULTS

We classified NK cells into seven distinct clusters and confirmed that a subset of ZNF683⁺ NK cells were enriched in MM patients with 'exhausted' transcriptomic profile, featuring as decreased expression of activating receptors and cytolytic molecules, as well as increased expression of inhibitory receptors. Next, we found a significant downregulation of SH2D1B gene that encodes EAT-2, an adaptor protein of activating receptor SLAMF7, in ZNF683⁺ NK cells from MM patients versus healthy volunteers. We further proved that ZNF683 transfection in NK cells significantly downregulated SH2D1B expression via directly binding to the promoter of SH2D1B, leading to NK cell cytotoxic activity impairment and exhausted phenotypes acquisition. In contrast, ZNF683 knockout in NK cells from MM patients increased cytotoxic activity and reversed NK cell exhaustion.

CONCLUSIONS

In summary, our findings uncover an important mechanism of ZNF683⁺ NK cell exhaustion and suggest that transcriptional suppressor ZNF683 as a potential useful therapeutic target in immunotherapy of MM.

Increased Expression of Mitochondrial UQCRC1 in Pancreatic Cancer Impairs Antitumor Immunity of Natural Killer Cells via Elevating Extracellular ATP

Pancreatic cancer (PC) is one of the most lethal malignancies characterized by a highly immunosuppressive tumor microenvironment (TME). Previously, we have reported that ubiquinol-cytochrome c reductase core protein I (UQCRC1), a key component of mitochondrial complex III, is generally upregulated in PC and produces extracellular ATP (eATP) to promote PC progression. Here, we sought to investigate whether the oncogenic property of UQCRC1 is generated through its effects on natural killer (NK) cells in the TME. We found that UQCRC1 overexpression in PC cells inhibited cytotoxicity of NK cells, as well as the infiltration of NK cells toward PC, whereas knockdown of UQCRC1 enhanced the cytotoxicity and chemotaxis of NK cells. Adoptive NK cell therapy in the subcutaneous mouse model and CIBERSORTx analysis with human PC specimens confirmed UQCRC1 elicited immunosuppressive effects on NK cells. Such UQCRC1-induced impairment of NK cells was mediated by eATP and its metabolite adenosine via P2Y11R and A2AR, respectively. Mechanistically, we found the UQCRC1/eATP axis reduced the expression of chemokine CCL5 in cancer cells and altered the balance of activating receptor DNAM-1 and inhibitory receptor CD96 on NK-92MI cells, resulting in decreased chemotaxis and exhausted phenotype of NK-92MI cells. Taken together, our study provides the evidence to support a novel mechanism by which energy metabolism change in cancer cells remodels the TME and impedes NK cell surveillance. It also suggests that targeting UQCRC1 may be a potential combined strategy for PC immunotherapy.

Killers on the loose: Immunotherapeutic strategies to improve NK cell-based therapy for cancer treatment

Natural killer (NK) cells are innate lymphocytes that control tumor progression by not only directly killing cancer cells, but also by regulating other immune cells, helping to orchestrate a coordinated anti-tumor response. However, despite the tremendous potential that this cell type has, the clinical results obtained from diverse NK cell-based immunotherapeutic strategies have been, until recent years, rather modest. The intrinsic regulatory mechanisms that are involved in the control of their activation as well as the multiple mechanisms that tumor cells have developed to escape NK cell-mediated cytotoxicity likely account for the unsatisfactory clinical outcomes. The current approaches to improve long-term NK cell function are centered on modulating different molecules involved in both the activation and inhibition of NK cells, and the latest data seems to advocate for combining strategies that target multiple aspects of NK cell regulation. In this review, we summarize the different strategies (such as engineered NK cells, CAR-NK, NK cell immune engagers) that are currently being used to take advantage of this potent and complex immune cell.

Triple-serotype chimeric oncolytic adenovirus exerts multiple synergistic mechanisms against solid tumors

Background

Oncolytic virotherapy has become an important branch of cancer immunotherapy. This study investigated the efficacy of an oncolytic adenovirus (OAV), OncoViron, with synergistic mechanisms in the treatment of multiple solid tumors.

Methods

An OAV, OncoViron, was constructed and investigated by cytological experiments and implanted tumor models of multiple solid tumor cell lines to certify its anticancer efficacy, the synergistic effects of viral oncolysis and transgene anticancer activity of OncoViron, as well as oncolytic virotherapy combined with immunotherapy, were also verified.

Results

The selective replication of OncoViron mediated high expression of anticancer factors, specifically targeted a variety of solid tumors and significantly inhibited cancer cell proliferation. On a variety of implanted solid tumor models in immunodeficient mice, immunocompetent mice, and humanized mice, OncoViron showed great anticancer effects on its own and in combination with programmed death 1 (PD-1) antibody and chimeric antigen receptor (CAR) T cells. Pathological examination, single-cell sequencing, and spatial transcriptome analysis of animal implanted tumor specimens confirmed that OncoViron significantly altered the gene expression profile of infected cancer cells, not only recruiting a large number of lymphocytes, natural killer cells, and mononuclear macrophages into tumor microenvironment (TME) and activated immune cells, especially T cells but also inducing M1 polarization of macrophages and promoting the release of more immune cytokines, thereby remodeling the TME for coordinating PD-1 antibody or CAR T therapy.

Conclusions

The chimeric OncoViron is a novel broad-spectrum anticancer product with multiple mechanisms of synergistic and potentiated immunotherapy, creating a good opportunity for combined immunotherapy against solid tumors.