Cytokine-armed oncolytic herpes simplex viruses: a game-changer in cancer immunotherapy?

Combining local cytokine delivery and systemic immunization with recombinant artLCMV boosts antitumor efficacy in several preclinical tumor models

Among the plethora of cancer immune evasion mechanisms, T-cell-inhibiting factors within the tumor microenvironment impose a major challenge for the development of novel immunotherapies. Strategies to overcome immunosuppression and remodel the TME are therefore urgently needed. Therapeutic cancer vaccines based on engineered arenaviruses have been proven to generate potent tumor specific CD8+ T-cell responses in preclinical models and cancer patients. Despite signs of clinical activity as monotherapy, combination therapies are needed to further increase the therapeutic effect. To address this need, we evaluated the efficacy of recombinant vectors based on lymphocytic choriomeningitis virus encoding the T-cell stimulating cytokines IL-7, IL-12 and IL-15 with or without tumor-associated antigens. These vectors were tested in three different mouse tumor models (TC-1, MC-38 and B16.F10). Our results demonstrate that only IL-12 encoding vectors led to increased immunogenicity and efficacy, which, after systemic administration, was associated with adverse events. The safest and most potent regimen consisted of systemic vaccination with tumor antigen encoding vectors and local injection of IL-12-encoding vectors. A single round of this treatment regimen resulted in 86-100% tumor-free mice and warrants further investigation.

The evolving landscape of oncolytic virus immunotherapy: combinatorial strategies and novel engineering approaches

Oncolytic viruses (OVs) are a promising class of cancer therapy, exploiting their abilities to selectively infect and kill cancer cells while stimulating antitumor immune responses. The current assessment explores the changing horizons of OV immunotherapy, focusing on recent advances in technology plans to improve OV projects and combined approaches to improve curative efficacy. We discuss how OVs induce direct oncolysis and promote the release of tumor-associated antigens, leading to the activation of both innate and adaptive immunity. Special attention shall be given to programs for arm OVs to express curative genes, modify the tumor microenvironment and overcome immunosuppression. Moreover, we assess the synergies of uniting OVs with other immunotherapeutic techniques, such as immune checkpoint inhibitors and cell therapy, to improve tolerant outcomes. The present assessment provides an understanding of the relevant declaration of the OV analysis, highlighting the main obstacles and the future directions for the development of other capable and targeted cancer immunotherapy.

The molecular mechanisms, roles, and potential applications of PANoptosis in cancer treatment

PANoptosis, a newly identified form of programmed cell death regulated by the panoptosome complex, exhibits key characteristics of apoptosis, pyroptosis and necroptosis. It exerts a substantial influence on the initiation and progression of a spectrum of diseases, particularly in cancer, where its impact is increasingly being recognized. PANoptosis is closely related to tumorigenesis, carcinogenesis, metastasis, chemotherapy resistance, as well as the prediction of therapeutic responses and prognosis in cancer patients. In this review, we first review the discovery of PANoptosis and systematically analyze the composition of the panoptosome. Subsequently, we examine the role of PANoptosis in various types of cancer, encompassing its function within the tumor microenvironment, its role in tumor drug resistance, and its predictive role in cancer prognosis. Ultimately, we delve into strategies for targeting PANoptosis in cancer therapy, including targeting various molecules in the PANoptosis pathway, such as ZBP1, RIPK1, RIPK3, Caspases and other novel strategies like nanoinducers and viral vectors. This review aims to provide references and assistance for the research and application of PANoptosis in cancer treatment.

Advances in the Drug Development and Quality Evaluation Principles of Oncolytic Herpes Simplex Virus

Oncolytic herpes simplex virus (oHSV) represents a promising therapeutic approach to treating cancers by virtue of its selective replication in and lysis of tumor cells, with stimulation of host antitumor immunity. At present, four OV drugs have been approved for the treatment of cancers worldwide, two of which are oHSV drugs that have received extensive attention, known as T-VEC and Delytact. This review discusses the history, mechanism of action, clinical development, quality control, and evaluation principles of oHSV products, including viral species and genetic modifications that have improved these products' therapeutic potential, limitations, and future directions. Integration of oHSVs with immunotherapeutic agents and conventional therapies has a promising future in the field of treatment of malignant tumors. Although much progress has been achieved, there is still much work to be done regarding the optimization of treatment protocols and the quality control of oncolytic virus drugs. The approval of various oncolytic virus therapies underlines their clinical relevance, safety, and efficacy, thereby paving the way for further research aimed at overcoming the existing limitations and enhancing patient responses.

Siglec-15 antibody-GM-CSF chimera suppresses tumor progression via reprogramming tumor-associated macrophages

BACKGROUND

Sialic acid-binding immunoglobulin-like lectin (Siglec)-15-expressing tumor-associated macrophages (TAMs) drive immunosuppression in the tumor microenvironment (TME), promoting CD8+ T cell exhaustion and limiting immunotherapy efficacy. Both blockade of immune checkpoint molecule Siglec-15 and promotion of granulocyte-macrophage colony-stimulating factor (GM-CSF) have been respectively employed in anticancer immunotherapy.

METHODS

Murine CT26 or MC38 cancer cells were used to establish subcutaneous tumor models in BALB/c or C57BL/6 mice. Tumors were treated with anti-Siglec-15 antibody-GM-CSF chimera (anti-S15×GM CSF) or anti-Siglec-15 antibody via intraperitoneal injection. The TME was analyzed by flow cytometry and ELISA for immune cell infiltration and cytokine levels. Biodistribution and half-life of anti-S15×GM CSF were assessed by intravenous injection in tumor-bearing mice, with GM-CSF levels measured by ELISA. Macrophage reprogramming and antigen presentation were evaluated using bone marrow-derived macrophages and human peripheral blood mononuclear cell-derived macrophages treated with anti-S15×GM CSF, followed by flow cytometry and immunofluorescence assays.

RESULTS

Here we report that anti-S15×GM CSF displays superior function to suppress the progression of Siglec-15-overexpressing MC38 colon cancer engrafted in mice compared to anti-Siglec-15 antibody or GM-CSF alone. Different from the injected GM-CSF which is distributed broadly in various organs and tissues of mouse, the injected anti-S15×GM CSF is preferentially accumulated in Siglec-15-positive tumor cells and TAMs. Anti-S15×GM CSF not only extends the half-life of GM-CSF in vivo, but also reduces the off-target effect of GM-CSF through TAM-specific delivery. In addition to Siglec-15 blockade, anti-S15×GM CSF effectively reprograms immunosuppressive TAMs to a proinflammatory phenotype, enhancing antigen presentation by macrophages to activate T cells.

CONCLUSIONS

In summary, our results reveal that anti-S15×GM CSF may serve as an effective therapeutic approach for solid tumors.

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.