Our laboratory is interested in identifying viral and cellular factors that mediate reovirus infection. Mammalian reovirus is a nonenveloped, dsRNA virus isolated from respiratory secretions and stool of children. Although most humans are seropositive by age five, reovirus rarely causes disease. Due to its preferential killing of transformed cells, reovirus is currently in Phase I-III clinical trials to test its efficacy as viral oncolytic therapeutic against several types of cancer. Our current focus is on understanding how reovirus uses bacteria and bacterial cell components to infect cells in the gut and genetically engineering reovirus as a viral oncolytic with enhanced cell killing of cancer cells.
Focus 1. To identify how reovirus infection of eukaryotic cells is altered by bacteria and bacterial membrane components.
Efficient reovirus infection of the gut requires the presence of bacteria, but how bacteria promote infection is not known. We are investigating how bacteria or specific bacterial membrane components interact with reovirus to convey enhanced infectivity of eukaryotic cells. We are working to assess whether this interaction affects virion stability, engagement of cell-surface receptors, uptake mechanisms, and whether the interaction is dependent on viral serotype. To achieve this, we are using a variety of techniques including infectivity and growth assays, immunofluoresence confocal microscopy, super-resolution microscopy, electron microscopy, and a variety of molecular techniques including flowcytometry and Westrn blotting. We are also interested in using 3D cell cultures to assess reovirus infection of gut epithelial cells and their response to infection.
Focus 2. To define determinants of reovirus-mediated killing of triple-negative breast cancer cells.
Triple-negative breast cancer (TNBC) cells are defined by the lack of estrogen and progesterone receptors and HER2/Neu expression. TNBC accounts for over 10% of breast cancers, is associated with a poor prognosis, and current therapies are not efficacious at treating the disease. We are using reverse and forward genetics to engineer oncolytic reoviruses with enhanced replication and killing of TNBC cells. To identify drugs that synergize reovirus killing of TNBC cells we are using high-throughput screening of a library of small molecule inhibitors. We are also interested in defining cell death pathways used by reovirus to kill specific subtypes of TNBC cells.
Bernardo A. Mainou (PI)
Roxana M. Rodriguez Stewart (Microbiology and Molecular Genetics Graduate Student)
Jameson Berry (Cancer Biology Graduate Student)
Shivali Singh (Emory Undergraduate Student)
Angela K. Berger (Postdoctoral Fellow) now an Assistant Professor of Biology at Trine University
1. Berger AK, Yi H, Kearns DB, Mainou BA. Bacteria and bacterial envelope components enhance mammalian reovirus thermostability. PLoS Pathogens December 6, 2017.
2. Berger AK and Mainou BA. Interactions between Enteric Bacteria and Eukaryotic Viruses Impact the Outcome of Infection. Viruses January 3, 2018.
3. Phillips MB, Stuart JD, Rodríguez Stewart RM, Berry JTL, Mainou BA, Boehme KW. Current understanding of reovirus oncolysis mechanisms. Oncolytic Virotherapy June 14, 2018.