Four billion people carry herpes simplex virus, and growing resistance to standard antivirals like acyclovir threatens effective treatment options. This challenge has intensified interest in host-directed therapies that sidestep viral mutations by targeting cellular pathways the virus commandeers for replication.
Researchers discovered that doxorubicin, an established chemotherapy agent, potently suppresses HSV-1 replication by disrupting the PI3K-AKT-mTOR signaling cascade in host cells. This pathway proves essential for viral entry and productive infection cycles. The drug demonstrated efficacy against both laboratory strains and clinical isolates already resistant to acyclovir, working at concentrations below those causing cellular toxicity. Combination studies revealed strong synergistic effects with nucleoside analog antivirals, potentially enabling lower therapeutic doses.
This host-targeting approach represents a fundamentally different antiviral strategy from direct viral enzyme inhibition. By disrupting cellular machinery rather than viral proteins, such therapies theoretically maintain effectiveness even as viruses mutate. The PI3K-AKT pathway's central role in cellular metabolism and growth makes it an attractive but complex target, given its involvement in normal physiological processes. The research also highlights potential complications for oncolytic virus therapies, where controlled viral replication is therapeutically desired. While promising for resistant infections, the clinical translation remains challenging given doxorubicin's established cardiotoxicity profile. The findings suggest a broader principle: repurposing approved drugs with known host effects could accelerate development of resistance-refractory antivirals, though careful dosing strategies would be essential to minimize systemic toxicity while preserving antiviral efficacy.