Concurrent chemotherapy inhibits herpes simplex virus-1 replication and oncolysis

Area of Science:

• Oncology
• Virology
• Molecular Biology

Background:

• Herpes simplex virus-1 (HSV-1) oncolysis is an experimental cancer therapy.
• Chemotherapy's impact on HSV-1 replication is not well understood.
• Cellular responses to chemotherapy can modulate viral activity.

Purpose of the Study:

• To investigate how chemotherapy agents affect HSV-1 replication and oncolysis.
• To examine the role of Nuclear Factor-κB (NF-κB) and eukaryotic initiation factor 2α (eIF-2α) in these interactions.

Main Methods:

• Colon and pancreatic cancer cells were exposed to 5-fluorouracil (5-FU), irinotecan (CPT-11), methotrexate (MTX), or tumor necrosis factor-α (TNF-α).
• HSV-1 replication and oncolysis were assessed in treated cells.
• NF-κB activation and eIF-2α dephosphorylation were analyzed.

Main Results:

• 5-FU, CPT-11, and MTX antagonized HSV-1 replication and oncolysis.
• NF-κB activation was required for efficient HSV-1 replication and was induced by 5-FU, CPT-11, TNF-α, and HSV-1.
• MTX did not activate NF-κB, suggesting a role in reduced viral replication.
• HSV-1-mediated eIF-2α dephosphorylation occurred normally despite chemotherapy exposure.

Conclusions:

• Cellular responses to chemotherapy create an unfavorable environment for HSV-1 oncolysis.
• These findings are relevant for designing preclinical and clinical studies of HSV-1 oncolysis combined with chemotherapy.