Investigating oncolytic virus M1-Associated vesicles using 3D electron microscopy

The oncolytic virus M1 (OVM) is recognized as an effective and promising oncolytic virus. Extensive research has been conducted to elucidate the molecular mechanisms underlying OVM's selective targeting and destruction of cancer cells. However, a comprehensive understanding of the biological processes involved in viral assembly and maturation within cancer cells remains elusive. In this study, we employed volume three-dimensional electron microscopy to examine Hs578T cells infected with OVM. Our findings not only identified four distinct types of cytopathic vesicles (CPVs) that emerged within the infected cancer cells but also revealed that CPV-II comprises two maturation-stage subtypes, CPV-II-1 and CPV-II-2, with the latter forming tree-like intracellular tunnel networks. Furthermore, the data presented here provide evidence for the release of mature virions through cytopathic vesicles type III. Collectively, our research sheds light on the developmental process of virus-associated vesicles, updates our understanding of OVM's viral release mechanisms, and refines the characterization of the OVM life cycle in cancer cells.