Respiratory Models Reveal DNA Damage Response Modulation by Merkel Cell Polyomavirus.

Merkel Cell Polyomavirus is an oncogenic virus associated with Merkel Cell Carcinoma (MCC). However, considering viral detection in respiratory specimens and similarities between MCC and neuroendocrine lung cancer, its plausible role in the respiratory tract is disputed. MCPyV-mediated oncogenesis involves viral antigens interfering with host signaling as a DNA Damage Response (DDR). In the current study, respiratory models, including lung cancer cell lines (A549 and H1299), and non-malignant bronchial systems (HBEC-KT and a 2D ALI model) were used to investigate DDR genes' expression following MCPyV infection. Once the capability to support viral replication and transcription was assessed using qPCR and RT-qPCR, respectively, the mRNA levels of DDR genes, including ATM, ATR, Chk1, Chk2, H2AX, Rad51, p53 and p21, were examined. Our findings showed MCPyV replication in all cellular systems, as proven by the detection of viral DNA and transcripts. Viral infection induced an overexpression of DDR genes, suggesting a role of the virus in manipulating DDR to favor its replication or contribute to tumor progression. These preliminary results provide in vitro models for studying the interplay between MCPyV and DDR within malignant and non-malignant contexts across the respiratory tract, laying the basis for future research exploring the clinical relevance of DDR activation in virus-driven malignancies.