Cellular senescence preserves viral genome maintenance

Senescent cells accumulate in the host during the aging process and are associated with age-related pathogenesis, including cancer. Although persistent senescence seems to contribute to many aspects of cellular pathways and homeostasis, the role of senescence in virus-induced human cancer is not well understood. Merkel cell carcinoma (MCC) is an aggressive skin cancer induced by a life-long human infection of Merkel cell polyomavirus (MCPyV). Here, we show that MCPyV large T (LT) antigen expression in human skin fibroblasts causes a novel nucleolar stress response followed by p21-dependent senescence and senescence-associated secretory phenotypes (SASPs) which are required for MCPyV genome maintenance. The senolytic, navitoclax, treatment resulted in decreased senescence and MCPyV genome levels, suggesting a potential therapeutic for MCC prevention. Our results uncover the mechanism of a host stress response regulating human polyomavirus genome maintenance in viral persistency, which may lead to the targeted intervention for MCC.