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.

Co-delivery of oncolytic virus and chemotherapeutic modality: Vincristine against prostate cancer treatment: A potent viro-chemotherapeutic approach.

Prostate cancer is a prevalent carcinoma among males, and conventional treatment options are often limited. Cytotoxic chemotherapy, despite its drawbacks, remains a mainstay. We propose a targeted co-delivery approach using nanoscale delivery units for Oncolytic measles virus (OMV) and vincristine (VC) to enhance treatment efficacy. The HA-coated OMV + VC-loaded TCs nanoformulation is designed for targeted oncolytic activity in prostate cancer. The CD44 expression analysis in prostate cancer cell lines indicates a significantly high expression in PC3 cells. The optimization of nanoformulations using Design of Expert (DOE) is performed, and the preparation and characterization of HA-coated OMV + VC-loaded TCs nanoformulations are detailed showing average particle size 397.2 ± 0.01 nm and polydispersity index 0.122 with zeta potential 19.7 + 0.01 mV. Results demonstrate successful encapsulation efficiency with 2.4 × 106 TCID50/Ml and sustained release of OMV and VC from the nanoformulation for up to 72 h. In vitro, assays reveal potent anticancer activity at 10 ± 0.71% cell viability in PC3 cells compared to 73 ± 0.66% in HPrEC and significant morphological changes at 90 µg/ml in dose and time-dependent manner. The co-formulation showed positive cell death 49.5 ± 0.02% at 50 µg PI/ml in PBS and 54.3% cell cycle arrest at the G2/M phase, 8.1% G0/G1 and 5.7% at S phase, with significant mitochondrial membrane potential (MMP) at 50 µg/ml, as assessed by flow cytometry (FACS). The surface-integrating ligand approach enhances the targeted delivery of the oncolytic virus and chemotherapeutic drug, presenting a potential alternative for prostate cancer treatment and suggested that co-administering VC and OMV in a nanoformulation could improve therapeutic outcomes while reducing chemotherapeutic drug doses.

Oncolytic Newcastle disease virus carrying the IL24 gene exerts antitumor effects by inhibiting tumor growth and vascular sprouting.

The second-leading cause of death, cancer, poses a significant threat to human life. Innovations in cancer therapies are crucial due to limitations in traditional approaches. Newcastle disease virus (NDV), a nonpathogenic oncolytic virus, exhibits multifunctional anticancer properties by selectively infecting, replicating, and eliminating tumor cells. To enhance NDV's antitumor activity, four oncolytic NDV viruses were developed, incorporating IL24 and/or GM-CSF genes at different gene loci using reverse genetics. In vitro experiments revealed that oncolytic NDV virus augmented the antitumor efficacy of the parental virus rClone30, inhibiting tumor cell proliferation, inducing tumor cell fusion, and promoting apoptosis. Moreover, NDV carrying the IL24 gene inhibited microvessel formation in CAM experiments. Evaluation in a mouse model of liver cancer confirmed the therapeutic efficacy of oncolytic NDV viral therapy. Tumors in mice treated with oncolytic NDV virus significantly decreased in size, accompanied by tumor cell detachment and apoptosis evident in pathological sections. Furthermore, oncolytic NDV virus enhanced T cell and dendritic cell production and substantially improved the survival rate of mice with hepatocellular carcinoma, with rClone30-IL24(P/M) demonstrating significant therapeutic effects. This study establishes a basis for utilizing oncolytic NDV virus as an antitumor agent in clinical practice.

Enhanced IL-12 transgene expression improves oncolytic viroimmunotherapy.

Introduction: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with unacceptably low cure rates occurring often in patients with neurofibromatosis 1 defects. To investigate oncolytic Herpes Simplex Virus (oHSV) as an immunotherapeutic approach, we compared viral replication, functional activity, and immune response between unarmed and interleukin 12 (IL-12)-armed oncolytic viruses in virus-permissive (B109) and -resistant (67C-4) murine MPNSTs. Methods: This study compared two attenuated IL-12-oHSVs with γ134.5 gene deletions (Δγ134.5) and the same transgene expression cassette. The primary difference in the IL-12-oHSVs was in their ability to counter the translational arrest response in infected cells. Unlike M002 (Δγ134.5, mIL-12), C002 (Δγ134.5, mIL-12, IRS1) expresses an HCMV IRS1 gene and evades dsRNA activated translational arrest in infected cells. Results and discussion: Our results show that oHSV replication and gene expression results in vitro were not predictive of oHSV direct oncolytic activity in vivo. Tumors that supported viral replication in cell culture studies resisted viral replication by both oHSVs and restricted M002 transgene expression in vivo. Furthermore, two IL-12-oHSVs with equivalent transcriptional activity differed in IL-12 protein production in vivo, and the differences in IL-12 protein levels were reflected in immune infiltrate activity changes as well as tumor growth suppression differences between the IL-12-oHSVs. C002-treated tumors exhibited sustained IL-12 production with improved dendritic cells, monocyte-macrophage activity (MHCII, CD80/CD86 upregulation) and a polyfunctional Th1-cell response in the tumor infiltrates. Conclusion: These results suggest that transgene protein production differences between oHSVs in vivo, in addition to replication differences, can impact OV-therapeutic activity.

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.

Synergistic antitumor immune response mediated by paclitaxel-conjugated nanohybrid oncolytic adenovirus with dendritic cell therapy.

Dendritic cell (DC)-based vaccines have emerged as a promising strategy in cancer immunotherapy due to low toxicity. However, the therapeutic efficacy of DC as a monotherapy is insufficient due to highly immunosuppressive tumor environment. To address these limitations of DC as immunotherapeutic agent, we have developed a polymeric nanocomplex incorporating (1) oncolytic adenovirus (oAd) co-expressing interleukin (IL)-12 and granulocyte-macrophage colony-stimulating factor (GM-CSF) and (2) arginine-grafted bioreducible polymer with PEGylated paclitaxel (APP) to restore antitumor immune surveillance function in tumor milieu and potentiate immunostimulatory attributes of DC vaccine. Nanohybrid complex (oAd/APP) in combination with DC (oAd/APP+DC) induced superior expression level of antitumor cytokines (IL-12, GM-CSF, and interferon gamma) than either oAd/APP or DC monotherapy in tumor tissues, thus resulting in superior intratumoral infiltration of both endogenous and exogenous DCs. Furthermore, oAd/APP+DC treatment led superior migration of DC to secondary lymphoid organs, such as draining lymph nodes and spleen, in comparison with either monotherapy. Superior migration profile of DCs in oAd/APP+DC treatment group resulted in more prolific activation of tumor-specific T cells in these lymphoid organs and greater intratumoral infiltration of T cells. Additionally, oAd/APP+DC treatment led to lower subset of tumor infiltrating lymphocytes and splenocytes being immunosuppressive regulatory T cells than any other treatment groups. Collectively, oAd/APP+DC led to superior induction of antitumor immune response and amelioration of immunosuppressive tumor microenvironment to elicit potent tumor growth inhibition than either monotherapy.

Oncolytic adenovirus encoding LHPP exerts potent antitumor effect in lung cancer.

LHPP has been shown to be a new tumor suppressor, and has a tendency to be under-expressed in a variety of cancers. Oncolytic virotheray is a promising therapeutics for lung cancer in recent decade years. Here we successfully constructed a new recombinant oncolytic adenovirus GD55-LHPP and investigated the effect of GD55-LHPP on the growth of lung cancer cells in vitro and in vivo. The results showed that LHPP had lower expression in either lung cancer cells or clinical lung cancer tissues compared with normal cells or tissues, and GD55-LHPP effectively mediated LHPP expression in lung cancer cells. GD55-LHPP could effectively inhibit the proliferation of lung cancer cell lines and rarely affected normal cell growth. Mechanically, the oncolytic adenovirus GD55-LHPP was able to induce stronger apoptosis of lung cancer cells compared with GD55 through the activation of caspase signal pathway. Notably, GD55-LHPP also activated autophagy-related signal pathway. Further, GD55-LHPP efficiently inhibited tumor growth in lung cancer xenograft in mice and prolonged animal survival rate compared with the control GD55 or PBS. In conclusion, the novel construct GD55-LHPP provides a valuable strategy for lung cancer-targeted therapy and develop the role of tumor suppress gene LHPP in lung cancer gene therapy.

Hypothesis: AdAPT-001 and pseudoprogression - when seeing is not necessarily believing.

The purpose of this commentary is to highlight the high occurrence of clinical pseudoprogression and delayed responses that have been observed to date with the locally injected oncolytic adenovirus, AdAPT-001, currently in a Phase 1/2 clinical trial (NCT04673942) for the treatment of treatment-refractory tumors. Not surprisingly, these have led to confusion about response assessment and whether to continue patients on treatment. AdAPT-001 carries a transforming growth factor (TGF)-beta trap (TGF-ß), which sequesters TGF-ß, a cytokine that potently regulates inflammation, fibrosis, and immunosuppression in cancer. Pseudoprogression (PsP) or progression prior to response or stabilization, has been widely recognized with radiotherapy for primary brain tumors and immune checkpoint inhibitors (ICIs). PsP has also been described and documented in the context of oncolytic virotherapy but perhaps to a lesser extent. However, repeated intratumoral injections with these immunostimulatory agents may induce a more intense immune response and release more antigenic epitopes than with ICIs, for example, which are strictly T-cell directed rather than also tumor-directed like AdAPT-001.

Oscillations in a Spatial Oncolytic Virus Model.

Virotherapy treatment is a new and promising target therapy that selectively attacks cancer cells without harming normal cells. Mathematical models of oncolytic viruses have shown predator-prey like oscillatory patterns as result of an underlying Hopf bifurcation. In a spatial context, these oscillations can lead to different spatio-temporal phenomena such as hollow-ring patterns, target patterns, and dispersed patterns. In this paper we continue the systematic analysis of these spatial oscillations and discuss their relevance in the clinical context. We consider a bifurcation analysis of a spatially explicit reaction-diffusion model to find the above mentioned spatio-temporal virus infection patterns. The desired pattern for tumor eradication is the hollow ring pattern and we find exact conditions for its occurrence. Moreover, we derive the minimal speed of travelling invasion waves for the cancer and for the oncolytic virus. Our numerical simulations in 2-D reveal complex spatial interactions of the virus infection and a new phenomenon of a periodic peak splitting. An effect that we cannot explain with our current methods.

Improvement of current immunotherapies with engineered oncolytic viruses that target cancer stem cells.

The heterogeneity of the solid tumor microenvironment (TME) impairs the therapeutic efficacy of standard therapies and also reduces the infiltration of antitumor immune cells, all of which lead to tumor progression and invasion. In addition, self-renewing cancer stem cells (CSCs) support tumor dormancy, drug resistance, and recurrence, all of which might pose challenges to the eradication of malignant tumor masses with current therapies. Natural forms of oncolytic viruses (OVs) or engineered OVs are known for their potential to directly target and kill tumor cells or indirectly eradicate tumor cells by involving antitumor immune responses, including enhancement of infiltrating antitumor immune cells, induction of immunogenic cell death, and reprogramming of cold TME to an immune-sensitive hot state. More importantly, OVs can target stemness factors that promote tumor progression, which subsequently enhances the efficacy of immunotherapies targeting solid tumors, particularly the CSC subpopulation. Herein, we describe the role of CSCs in tumor heterogeneity and resistance and then highlight the potential and remaining challenges of immunotherapies targeting CSCs. We then review the potential of OVs to improve tumor immunogenicity and target CSCs and finally summarize the challenges within the therapeutic application of OVs in preclinical and clinical trials.

Enhancement of Therapeutic Potential of Oncolytic Virus with Homologous Tumor Cell Membranes for Pancreatic Cancer.

Pancreatic cancer is a leading cause of cancer-related deaths worldwide. Conventional therapies often provide limited success, necessitating the need for novel therapeutic strategies. Oncolytic viruses (OVs) are a class of viruses that specifically target and kill cancer cells while leaving normal cells unharmed. These viruses have shown promise in the treatment of various cancers, including pancreatic cancer. However, their use in clinical settings has been limited by several factors. Their inability to efficiently infect and kill tumor cells. To overcome this limitation, a cell membrane-coated oncolytic virus was developed. However, the necessity of homologous and nonhomologous tumor cell membranes for their function has not yet been proven. This novel virus displayed increased infectivity and killing activity against tumor cells compared to nonhomologous tumor cell membranes and noncoated viruses. We believe that the homologous tumor cell membranes-coated OVs can enhance the therapeutic potential for pancreatic cancer therapy.

The role of immune cells in resistance to oncolytic viral therapy.

Resistance to treatment poses a major challenge for cancer therapy, and oncoviral treatment encounters the issue of viral resistance as well. In this investigation, we introduce deterministic differential equation models to explore the effect of resistance on oncolytic viral therapy. Specifically, we classify tumor cells into resistant, sensitive, or infected with respect to oncolytic viruses for our analysis. Immune cells can eliminate both tumor cells and viruses. Our research shows that the introduction of immune cells into the tumor-virus interaction prevents all tumor cells from becoming resistant in the absence of conversion from resistance to sensitivity, given that the proliferation rate of immune cells exceeds their death rate. The inclusion of immune cells leads to an additional virus-free equilibrium when the immune cell recruitment rate is sufficiently high. The total tumor burden at this virus-free equilibrium is smaller than that at the virus-free and immune-free equilibrium. Therefore, immune cells are capable of reducing the tumor load under the condition of sufficient immune strength. Numerical investigations reveal that the virus transmission rate and parameters related to the immune response significantly impact treatment outcomes. However, monotherapy alone is insufficient for eradicating tumor cells, necessitating the implementation of additional therapies. Further numerical simulation shows that combination therapy with chimeric antigen receptor (CAR T-cell) therapy can enhance the success of treatment.

PD-L1 promotes oncolytic virus infection via a metabolic shift that inhibits the type I IFN pathway.

While conventional wisdom initially postulated that PD-L1 serves as the inert ligand for PD-1, an emerging body of literature suggests that PD-L1 has cell-intrinsic functions in immune and cancer cells. In line with these studies, here we show that engagement of PD-L1 via cellular ligands or agonistic antibodies, including those used in the clinic, potently inhibits the type I interferon pathway in cancer cells. Hampered type I interferon responses in PD-L1-expressing cancer cells resulted in enhanced efficacy of oncolytic viruses in vitro and in vivo. Consistently, PD-L1 expression marked tumor explants from cancer patients that were best infected by oncolytic viruses. Mechanistically, PD-L1 promoted a metabolic shift characterized by enhanced glycolysis rate that resulted in increased lactate production. In turn, lactate inhibited type I IFN responses. In addition to adding mechanistic insight into PD-L1 intrinsic function, our results will also help guide the numerous ongoing efforts to combine PD-L1 antibodies with oncolytic virotherapy in clinical trials.

Quantitative Virus-Associated RNA Detection to Monitor Oncolytic Adenovirus Replication.

Oncolytic adenoviruses are in development as immunotherapeutic agents for solid tumors. Their efficacy is in part dependent on their ability to replicate in tumors. It is, however, difficult to obtain evidence for intratumoral oncolytic adenovirus replication if direct access to the tumor is not possible. Detection of systemic adenovirus DNA, which is sometimes used as a proxy, has limited value because it does not distinguish between the product of intratumoral replication and injected virus that did not replicate. Therefore, we investigated if detection of virus-associated RNA (VA RNA) by RT-qPCR on liquid biopsies could be used as an alternative. We found that VA RNA is expressed in adenovirus-infected cells in a replication-dependent manner and is secreted by these cells in association with extracellular vesicles. This allowed VA RNA detection in the peripheral blood of a preclinical in vivo model carrying adenovirus-injected human tumors and on liquid biopsies from a human clinical trial. Our results confirm that VA RNA detection in liquid biopsies can be used for minimally invasive assessment of oncolytic adenovirus replication in solid tumors in vivo.

Combination of FOLFOXIRI Drugs with Oncolytic Coxsackie B3 Virus PD-H Synergistically Induces Oncolysis in the Refractory Colorectal Cancer Cell Line Colo320.

FOLFOXIRI chemotherapy is a first-line therapy for advanced or metastatic colorectal cancer (CRC), yet its therapeutic efficacy remains limited. Immunostimulatory therapies like oncolytic viruses can complement chemotherapies by fostering the infiltration of the tumor by immune cells and enhancing drug cytotoxicity. In this study, we explored the effect of combining the FOLFOXIRI chemotherapeutic agents with the oncolytic coxsackievirus B3 (CVB3) PD-H in the CRC cell line Colo320. Additionally, we examined the impact of the drugs on the expression of microRNAs (miRs), which could be used to increase the safety of oncolytic CVB3 containing corresponding miR target sites (miR-TS). The measurement of cytotoxic activity using the Chou-Talalay combination index approach revealed that PD-H synergistically enhanced the cytotoxic activity of oxaliplatin (OX), 5-fluorouracil (5-FU) and SN-38. PD-H replication was not affected by OX and SN-38 but inhibited by high concentrations of 5-FU. MiR expression levels were not or only slightly elevated by the drugs or with drug/PD-H combinations on Colo320 cells. Moreover, the drug treatment did not increase the mutation rate of the miR-TS inserted into the PD-H genome. The results demonstrate that the combination of FOLFOXIRI drugs and PD-H may be a promising approach to enhance the therapeutic effect of FOLFOXIRI therapy in CRC.

The Application of Newcastle Disease Virus (NDV): Vaccine Vectors and Tumor Therapy.

Newcastle disease virus (NDV) is an avian pathogen with an unsegmented negative-strand RNA genome that belongs to the Paramyxoviridae family. While primarily pathogenic in birds, NDV presents no threat to human health, rendering it a safe candidate for various biomedical applications. Extensive research has highlighted the potential of NDV as a vector for vaccine development and gene therapy, owing to its transcriptional modularity, low recombination rate, and lack of a DNA phase during replication. Furthermore, NDV exhibits oncolytic capabilities, efficiently eliciting antitumor immune responses, thereby positioning it as a promising therapeutic agent for cancer treatment. This article comprehensively reviews the biological characteristics of NDV, elucidates the molecular mechanisms underlying its oncolytic properties, and discusses its applications in the fields of vaccine vector development and tumor therapy.

Tepilamide Fumarate as a Novel Potentiator of Virus-Based Therapy.

Oncolytic virotherapy, using viruses such as vesicular stomatitis virus (VSVΔ51) and Herpes Simplex Virus-1 (HSV-1) to selectively attack cancer cells, faces challenges such as cellular resistance mediated by the interferon (IFN) response. Dimethyl fumarate (DMF) is used in the treatment of multiple sclerosis and psoriasis and is recognized for its anti-cancer properties and has been shown to enhance both VSVΔ51 and HSV-1 oncolytic activity. Tepilamide fumarate (TPF) is a DMF analog currently undergoing clinical trials for the treatment of moderate-to-severe plaque psoriasis. The aim of this study was to evaluate the potential of TPF in enhancing the effectiveness of oncolytic viruses. In vitro, TPF treatment rendered 786-0 carcinoma cells more susceptible to VSVΔ51 infection, leading to increased viral replication. It outperformed DMF in both increasing viral infection and increasing the killing of these resistant cancer cells and other cancer cell lines tested. Ex vivo studies demonstrated TPF's selective boosting of oncolytic virus infection in cancer cells without affecting healthy tissues. Effectiveness was notably high in pancreatic and ovarian tumor samples. Our study further indicates that TPF can downregulate the IFN pathway through a similar mechanism to DMF, making resistant cancer cells more vulnerable to viral infection. Furthermore, TPF's impact on gene therapy was assessed, revealing its ability to enhance the transduction efficiency of vectors such as lentivirus, adenovirus type 5, and adeno-associated virus type 2 across various cell lines. This data underscore TPF's potential role in not only oncolytic virotherapy but also in the broader application of gene therapy. Collectively, these findings position TPF as a promising agent in oncolytic virotherapy, warranting further exploration of its therapeutic potential.

Beyond Immune Checkpoint Inhibitors: Emerging Targets in Melanoma Therapy.

PURPOSE OF REVIEW: This review provides a comprehensive update on recent advancements in melanoma treatment by highlighting promising therapeutics with an aim to increase awareness of novel interventions currently in development. RECENT FINDINGS: Over the last decade there has been considerable expansion of the previously available treatment options for patients with melanoma. In particular, novel immunotherapeutics have been developed to expand on the clinical advancements brought by BRAF targeting and immune checkpoint inhibitors. Despite the success of checkpoint inhibitors there remains an unmet need for patients that do not respond to treatment. This review delves into the latest advancements in novel checkpoint inhibitors, cytokines, oncolytic viruses, vaccines, bispecific antibodies, and adoptive cell therapy. Preclinical experiments and early-stage clinical trials studies have demonstrated promising results for these therapies, many of which have moved into pivotal, phase 3 studies.

EXPRESSION OF CONCERN: Therapeutic targeting of chemoresistant and recurrent glioblastoma stem cells with a proapoptotic variant of oncolytic herpes simplex virus.

EXPRESSION OF CONCERN: Nusrat Jahan, Jae M. Lee, Khalid Shah, Hiroaki Wakimoto, "Therapeutic targeting of chemoresistant and recurrent glioblastoma stem cells with a proapoptotic variant of oncolytic herpes simplex virus", International Journal of Cancer 141, no. 8 (2017): 1671-1681. https://doi.org/10.1002/ijc.30811. This Expression of Concern is for the above article, published online on 31 May 2017, in Wiley Online Library (wileyonlinelibrary.com), and has been published by agreement between the authors, the journal's Editor-in-Chief, Christoph Plass, the Union for International Cancer Control and John Wiley & Sons, Ltd. The Expression of Concern has been agreed following concerns raised regarding figure 4g and 5d. The Control (PBS) 4X DAPI image in figure 5d was found to contain elements similar to the Control (PBS) DAPI image presented in figure 4g. The authors admitted that they had mistakenly supplied the incorrect image to represent DAPI in figure 5d. Since the original DAPI image for figure 5d is no longer available, this issue could not be resolved. The journal has decided to issue an Expression of Concern to alert the readers.