Oncolytic Reovirus Infection Is Facilitated by the Autophagic Machinery

Area of Science:

• Virology
• Cell Biology
• Cancer Research

Background:

• Mammalian reovirus is a double-stranded RNA virus with oncolytic potential, selectively targeting and lysing cancer cells.
• Clinical trials show anti-tumor activity, but its efficacy as a standalone therapy needs improvement.
• Understanding cellular pathways regulating reovirus replication and oncolysis is key for enhancing future clinical success.

Purpose of the Study:

• To investigate the role of autophagy in mammalian reovirus infection and replication.
• To identify specific autophagy-related genes essential for reovirus replication.

Main Methods:

• Assessed autophagy induction in reovirus-infected cell lines using markers like Atg5-Atg12 complex formation, LC3 lipidation, p62 degradation, and LC3 puncta.
• Utilized electron microscopy to observe autophagosomes in infected cells.
• Employed UV-inactivated reovirus to confirm the necessity of productive infection for autophagy induction.
• Generated and analyzed knock-out cell lines for autophagy-related genes (Atg3, Atg5, Atg13) to determine their role in reovirus replication.

Main Results:

• Reovirus infection induces autophagy in various cell lines, confirmed by multiple established markers.
• Autophagosomes were observed in infected cells, independent of viral factories.
• Productive reovirus infection, not UV-inactivated virus, is required to trigger autophagy.
• Reovirus replication was significantly facilitated by the expression of Atg3 and Atg5, but not Atg13.

Conclusions:

• Autophagy plays a significant role in mammalian reovirus infection.
• Atg3 and Atg5 are critical host factors that promote reovirus replication in an Atg13-independent manner.
• These findings enhance understanding of reovirus-host interactions and inform strategies for optimizing oncolytic reovirus therapy.