Merkel Cell Polyomavirus Downregulates N-myc Downstream-Regulated Gene 1, Leading to Cellular Proliferation and Migration

Abstract

Merkel cell polyomavirus (MCPyV) is the first human polyomavirus etiologically associated with Merkel cell carcinoma (MCC), a rare and aggressive form of skin cancer. Similar to other polyomaviruses, MCPyV encodes early T antigen genes, viral oncogenes required for MCC tumor growth. To identify the unique oncogenic properties of MCPyV, we analyzed the gene expression profiles in human spontaneously immortalized keratinocytes (NIKs) expressing the early genes from six distinct human polyomaviruses (PyVs), including MCPyV. A comparison of the gene expression profiles revealed 28 genes specifically deregulated by MCPyV. In particular, the MCPyV early gene downregulated the expression of the tumor suppressor gene N-myc downstream-regulated gene 1 (NDRG1) in MCPyV gene-expressing NIKs and hTERT-MCPyV gene-expressing human keratinocytes (HK) compared to their expression in the controls. In MCPyV-positive MCC cells, the expression of NDRG1 was downregulated by the MCPyV early gene, as T antigen knockdown rescued the level of NDRG1. In addition, NDRG1 overexpression in hTERT-MCPyV gene-expressing HK or MCC cells resulted in a decrease in the number of cells in S phase and cell proliferation inhibition. Moreover, a decrease in wound healing capacity in hTERT-MCPyV gene-expressing HK was observed. Further analysis revealed that NDRG1 exerts its biological effect in Merkel cell lines by regulating the expression of the cyclin-dependent kinase 2 (CDK2) and cyclin D1 proteins. Overall, NDRG1 plays an important role in MCPyV-induced cellular proliferation. IMPORTANCE Merkel cell carcinoma was first described in 1972 as a neuroendocrine tumor of skin, most cases of which were reported in 2008 to be caused by a PyV named Merkel cell polyomavirus (MCPyV), the first PyV linked to human cancer. Thereafter, numerous studies have been conducted to understand the etiology of this virus-induced carcinogenesis. However, it is still a new field, and much work is needed to understand the molecular pathogenesis of MCC. In the current work, we sought to identify the host genes specifically deregulated by MCPyV, as opposed to other PyVs, in order to better understand the relevance of the genes analyzed on the biological impact and progression of the disease. These findings open newer avenues for targeted drug therapies, thereby providing hope for the management of patients suffering from this highly aggressive cancer.

Novel SARS-CoV-2 encoded small RNAs in the passage to humans

“…The deregulation of the tumor suppressor NDRG1 has been associated with the progression of lung cancer [78]. Strikingly, infection by Merkel Cell Polyomavirus leads to NDRG1 down-regulation and cellular proliferation and migration [79]. Further, the Porcine Reproductive and Respiratory Syndrome virus was found to facilitate viral replication through the downregulation of NDRG1 [80].…”

Merkel Cell Polyomavirus and Merkel Cell Carcinoma

“…Stable expressing the entire MCPyV early region in human immortalized keratinocytes resulted in >1.5-fold up- or down-regulated of 325 genes [ 152 ]. Of these, 73 had decreased expression and the majority encodes proteins involved in cell senescence, DNA repair, signal transduction, and cell cycle regulation, including HIST1H1C.…”

Machine Learning for Building Immune Genetic Model in Hepatocellular Carcinoma Patients

“…N-myc downregulated 1 (NDRG1) was a tumor suppressor, which has been reported in various studies; it could attenuate NF-kB and TGF-b pathways in pancreatic cancer cells, and downregulated NDRG1 was related to increased proliferation, invasion, and migration of digestive cancers [30][31][32][33]. It additionally involves apoptosis, glycolytic, and lipid metabolism in cancer cells, and virus infection process was also related to NDRG1 [34][35][36][37][38][39][40]. Another signature, mitogen-activated protein kinase 2 (MAP4K2), was involved in MAPK signaling pathway, which corroborated with the enrichment results.…”