Harnessing the Potential of Combination Immunotherapy and Oncolytic Virotherapy for Solid Tumors

Oncolytic viruses: a promising therapy for malignant pleural effusion and solid tumors

Oncolytic viruses (OVs) are natural or recombinant viruses that can directly lyse tumor cells without damaging normal cells. They enhance anti-tumor immunity by releasing antigens and activating inflammatory responses within the tumor microenvironment (TME). This offers a new therapeutic approach for MPE and solid tumors. This review discusses the progress of OVs administered via intrapleural and intratumoral routes, emphasizing their potential in MPE treatment and the challenges posed by the complex intrapleural environment, which affects the direct interaction between OVs, tumor cells, and immune cells. This review also discusses the regulatory barriers, safety concerns and accessibility of oncolytic virus therapy.

Use of patient-derived organotypic tumor spheroids for testing of viral vector gene therapy in combination with checkpoint blockade

Checkpoint inhibitors have revolutionized cancer treatment, but a significant proportion of patients do not respond to these therapies, underscoring the need for alternative strategies. Although gene therapy has made substantial strides, its application in solid tumors remains underexplored, with limited treatments approved. Here, we further investigated a gene therapy approach with non-replicating adenoviral vectors encoding the alternate reading frame (ARF) and interferon beta (IFNb) and tested it in a clinically relevant setting. We previously showed that this combined gene therapy induces immunogenic cell death in melanoma models, and now, we utilize patient-derived organotypic tumor spheroids (PDOTS), a model that closely recapitulates the immune environment of tumors, to test its effects using patient tumors. Our results demonstrate, for the first time, the effectiveness of using PDOTS to evaluate viral-vector-based gene therapies. While the addition of anti-PD-1 did not enhance therapeutic outcomes, the gene therapy alone suppressed tumor growth and triggered antitumor immune responses across different cancer models, notably those with low immunogenicity and specific genome profiles. These findings suggest that this gene therapy could serve as a valuable alternative for patients not responsive to checkpoint inhibitors and who have solid tumors with limited treatment and impaired p53-ARF-MDM2 pathways, such as liposarcomas.

Oncolytic virus delivery modulated immune responses toward cancer therapy: Challenges and perspectives

Oncolytic viruses (OVs) harness the hallmarks of tumor cells and cancer-related immune responses for the lysis of malignant cells, modulation of the tumor microenvironment, and exertion of vaccine-like activities. However, efficient clinical exploitation of these potent therapeutic modules requires their systematic administration, especially against metastatic and solid tumors. Therefore, developing methods for shielding a virus from the neutralizing environment of the bloodstream while departing toward tumor sites is a must. This paper reports the latest advancements in the employment of chemical and biological compounds aimed at safe and efficient delivery of OVs to target tissues or tumor deposits within the host.