Oncolytic measles virus reprograms the tumor microenvironment in a vascularized mesothelioma-on-chip model

Pleural mesothelioma (PM) is a rare, aggressive cancer primarily caused by asbestos exposure and remains resistant to conventional chemotherapy. Although dual immune checkpoint inhibition (anti-PD-1/anti-CTLA-4) is now approved as first-line therapy, clinical benefit is limited to a small subset of patients, necessitating the need for alternative strategies. Oncolytic viruses (OVs) represent a promising approach as they selectively infect and lyse tumor cells while reprogramming the immunosuppressive tumor microenvironment (TME) into an immunostimulatory state. In PM, we previously showed that the attenuated Schwarz strain of measles virus (MV) oncolytic activity is mainly dependent on alterations in the type I interferon (IFN-I) pathway, rendering tumor cells sensitive to infection. Recently, we showed that monocytes/macrophages exposed to MV produce IFN-I, which protects PM cells via paracrine IFNAR signaling. This underscores the necessity of modeling the TME to accurately evaluate OV efficacy. Conventional rodent models are non-permissive to MV, and availability of fresh human PM tissue is scarce. We therefore developed a humanized 3D "vascularized mesothelioma-on-chip" (VMOC) model using microfluidic chips. It comprises two perfusable endothelial-lined parental vessels flanking a central secondary microvascular network (MVN), generated using human umbilical vein endothelial cells (HUVECs) embedded in fibrin and co-cultured alongside PM cells and primary human lung fibroblasts (hLFs). We characterized the integrity and functionality of the endothelial compartment as well as the cellular heterogeneity in VMOC using single-cell RNA sequencing. After administration of MV via the endothelial network, we observed infection and death of PM cells in addition to a strong activation of the type I interferon pathway and production of multiple inflammatory mediators. The VMOC model enables in vitro study of both MV infection and TME reprogramming, paving the way for a better understanding of the role of the TME in the response to treatment and for supporting the development of more personalized, targeted therapies for PM.