Project description:Merkel cell carcinoma is supposed to be derived from Merkel cells after infection by Merkel cell polyomavirus (MCV) and other poorly known events. A transcriptional profiling with cDNA microarrays was performed on cells from MCV+ Merkel cell carcinomas and isolated normal Merkel cells. This microarray revealed numerous significantly upregulated genes and down-regulated genes. The extensive list of genes identified in these experiments provides a large body of potentially valuable information of Merkel cell carcinoma carcinogenesis and could represent a source of potential targets for cancer therapy. Two-conditions experiment, MCV vs Normal Merkel Cell. Biological replicates : 4 MCV (Cy5), 1 control = pool of Normal Merkel cells from 3 liftings
Project description:Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine tumor with high mortality rates. Merkel cell polyomavirus (MCPyV), identified in the majority of MCC, may drive tumorigenesis via viral T antigens. However, mechanisms underlying pathogenesis in MCPyV-negative MCC remain poorly understood. To nominate genes contributing to pathogenesis of MCPyV-negative MCC, we performed DNA microarray analysis on 30 MCCs. MCPyV status of MCCs was determined by PCR for viral DNA and RNA. 1593 probe-sets were differentially expressed between MCPyV-negative and -positive MCC, with significant differential expression defined as at least 2-fold change in either direction and p-value of ≤ 0.05. MCPyV-negative tumors showed decreased RB1 expression, whereas MCPyV-positive tumors were enriched for immune response genes. Validation studies included immunohistochemistry demonstration of decreased RB protein expression in MCPyV-negative tumors and increased peritumoral CD8+ T lymphocytes surrounding MCPyV-positive tumors. In conclusion, our data suggest that loss of RB1 expression may play an important role in tumorigenesis of MCPyV-negative MCC. Functional and clinical validation studies are needed to determine whether this tumor suppressor pathway represents an avenue for targeted therapy. We used microarrays to characterize global gene expression patterns related to Merkel cell polyomavirus status in Merkel cell carcinoma. Furthermore, we compared Merkel cell carcinoma to less aggressive primary cutaneous carcinomas. We utilized flash-frozen tumor tissue from primary Merkel cell carcinomas, metastatic Merkel cell carcinomas, primary cutaneous squamous cell carcinomas, and basal cell carcinomas. Merkel cell carcinoma cell lines, which represent a pure population of tumor cells, were also included. Merkel cell polyomavirus status was determined at the DNA and RNA level using multiple primers for viral T-antigen and capsid protein sequences. This Series represents two analyses - one with new Samples normalized together, and another with some of the new Samples re-normalized with Samples previously submitted under Series GSE13355. The latter group contain 'renormalized' in the titles.
Project description:Merkel cell carcinoma is supposed to be derived from Merkel cells after infection by Merkel cell polyomavirus (MCPyV) and other poorly known events. A transcriptional profiling with cDNA microarrays was performed on cells from MCPyV(+) Merkel cell carcinomas and isolated normal Merkel cells. This microarray revealed numerous significantly upregulated genes and downregulated genes. The extensive list of genes identified in these experiments provides a large body of potentially valuable information of Merkel cell carcinoma carcinogenesis and could represent a source of potential targets for cancer therapy.
Project description: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, a viral oncogene required for MCC tumor growth. To identify the unique oncogenic properties of MCPyV, we analysed the gene expression profiles in human spontaneously immortalized keratinocytes (NIKs) expressing the early genes from five distinct human polyomaviruses (PyVs), including MCPyV. A comparison of the gene expression profiles revealed 28 genes specifically deregulated by MCPyV.
Project description:Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine tumor with high mortality rates. Merkel cell polyomavirus (MCPyV), identified in the majority of MCC, may drive tumorigenesis via viral T antigens. However, mechanisms underlying pathogenesis in MCPyV-negative MCC remain poorly understood. To nominate genes contributing to pathogenesis of MCPyV-negative MCC, we performed DNA microarray analysis on 30 MCCs. MCPyV status of MCCs was determined by PCR for viral DNA and RNA. 1593 probe-sets were differentially expressed between MCPyV-negative and -positive MCC, with significant differential expression defined as at least 2-fold change in either direction and p-value of ≤ 0.05. MCPyV-negative tumors showed decreased RB1 expression, whereas MCPyV-positive tumors were enriched for immune response genes. Validation studies included immunohistochemistry demonstration of decreased RB protein expression in MCPyV-negative tumors and increased peritumoral CD8+ T lymphocytes surrounding MCPyV-positive tumors. In conclusion, our data suggest that loss of RB1 expression may play an important role in tumorigenesis of MCPyV-negative MCC. Functional and clinical validation studies are needed to determine whether this tumor suppressor pathway represents an avenue for targeted therapy. We used microarrays to characterize global gene expression patterns related to Merkel cell polyomavirus status in Merkel cell carcinoma. Furthermore, we compared Merkel cell carcinoma to less aggressive primary cutaneous carcinomas.
Project description:Merkel cell polyomavirus (MCPyV) is linked to Merkel cell carcinoma (MCC), a rare and aggressive skin cancer. This study investigated the influence of MCPyV T antigens on the host genome using transcriptomics and epigenomics. Results revealed a role for the small Tumor (sT) antigen in subverting type I interferon response and immune evasion, contributing to persistent infection and tumor progression. These findings enhance our understanding of MCPyV pathogenesis and may inform new therapeutic strategies.
Project description:Merkel cell polyomavirus (MCPyV) is linked to Merkel cell carcinoma (MCC), a rare and aggressive skin cancer. This study investigated the influence of MCPyV T antigens on the host genome using transcriptomics and epigenomics. Results revealed a role for the small Tumor (sT) antigen in subverting type I interferon response and immune evasion, contributing to persistent infection and tumor progression. These findings enhance our understanding of MCPyV pathogenesis and may inform new therapeutic strategies.
Project description:Polyomaviruses are small, circular dsDNA viruses that can cause cancer. Alternative splicing of polyomavirus early transcripts generates large and small tumor antigens (LT, ST) that play essential roles in viral replication and tumorigenesis. Some polyomaviruses also express middle tumor antigens (MTs) or alternate LT open reading frames (ALTOs), which are evolutionarily related but have distinct gene structures. MTs are a splice variant of the early transcript whereas ALTOs are overprinted on the second exon of the LT transcript in an alternate reading frame and are translated via an alternative start codon. Merkel cell polyomavirus (MCPyV), the only human polyomavirus that causes cancer, encodes an ALTO but its role in the viral lifecycle and tumorigenesis has remained elusive. Here, we performed bulk RNA sequencing in MKL-2 cells, a Merkel cell carcinoma cell line, expressing MCPyV ALTO or RFP as a negative control via a doxycycline inducible lentiviral vector. The goal of the study was to identify Differentially Expressed Genes and pathways activated or inhibited via Gene Set Enrichment Analysis.
Project description:Merkel cells are epidermal mechanoreceptor cells responsible for the perception of gentle touch. Merkel cell carcinoma (MCC) is a rare and highly aggressive skin cancer. Although MCC histologically resembles Merkel cells, the cell of origin for MCC is unknown. MCC frequently contains integrated Merkel cell polyomavirus (MCPyV), a small DNA tumor virus with widespread prevalence. Whether MCPyV can transform Merkel cells is unknown. Here, we describe the isolation and long-term expansion of human Merkel cells from neonatal foreskin. We validated the expression of several Merkel cell-related factors by RNASeq, and assessed the ultrastructure by electron microscopy. Culture of Merkel cell preparations on an artificial basement membrane promoted the formation of structures containing both Merkel and non-Merkel cell populations. To determine whether Merkel cells were susceptible to transformation, we expressed tumor-derived MCPyV T antigens and additional oncogenes. We were unable to demonstrate tumorigenesis in immunodeficient mice, but were able to detect T antigen expression from excised cells weeks after implantation. These results highlight that foreskin-isolated Merkel cells can be propagated extensively, sustain expression of MCPyV T antigens, but are not susceptible to transformation by MCPyV, suggesting that Merkel cells from non-glabrous skin may not be a cell of origin for MCC.