Integrated Proteomics and Genomics Analysis Reveals a Novel Mesenchymal to Epithelial Reverting Transition in Leiomyosarcoma through Regulation of Slug

Abstract

Leiomyosarcoma is one of the most common mesenchymal tumors. Proteomics profiling analysis by reversephase protein lysate array surprisingly revealed that expression of the epithelial marker E-cadherin (encoded by CDH1) was significantly elevated in a subset of leiomyosarcomas. In contrast, E-cadherin was rarely expressed in the gastrointestinal stromal tumors, another major mesenchymal tumor type. We further sought to 1) validate this finding, 2) determine whether there is a mesenchymal to epithelial reverting transition (MErT) in leiomyosarcoma, and if so 3) elucidate the regulatory mechanism responsible for this MErT. Our data showed that the epithelial cell markers E-cadherin, epithelial membrane antigen, cytokeratin AE1/AE3, and pan-cytokeratin were often detected immunohistochemically in leiomyosarcoma tumor cells on tissue microarray. Interestingly, the E-cadherin protein expression was correlated with better survival in leiomyosarcoma patients. Whole genome microarray was used for transcriptomics analysis, and the epithelial gene expression signature was also associated with better survival. Bioinformatics analysis of transcriptome data showed an inverse correlation between E-cadherin and E-cadherin repressor Slug (SNAI2) expression in leiomyosarcoma, and this inverse correlation was vali- The adhesion protein E-cadherin, encoded by CDH1, plays a central part in the process of epithelial morphogenesis. The down-regulation of E-cadherin is associated with a process called epithelial to mesenchymal transition (EMT) 1 that accounts for increased invasion and metastasis during tumor progression in multiple carcinomas of epithelial origin (1-5). Altered expression of E-cadherin has been shown to be regulated through several transcriptional factors such as Snail, SIP1, Twist, and Slug (encoded by SNAI2) and non-coding RNA such as miR-200 and let-7 (3-9). EMT of epithelial cancer cells is characterized by acquisition of fibroblast-like properties with reduced intercellular adhesion and increased motility in vitro as well as metastasis (2, 5, 10). Recently, a similar but reverse process called mesenchymal to epithelial reverting transition (MErT) has been observed and reported (11). Ecadherin is also a key indicator of MErT during the metastatic seeding of disseminated carcinomas (11). In synovial sarcoma, the fusion protein SYT-SSX1 has been shown to induce MErT through the regulation of SNAI1 and Slug (12). These investigations suggest that MErT might be an important biological process for tumors of mesenchymal origin, although E-cadherin expression is infrequent in most sarcomas examined thus far (13).Leiomyosarcomas and gastrointestinal stromal tumors (GISTs), two of the most common mesenchymal tumors, share remarkably similar phenotypic features but are molecFrom the Departments of

Evolution of Dermatofibrosarcoma Protuberans to DFSP-Derived Fibrosarcoma: An Event Marked by Epithelial–Mesenchymal Transition–like Process and 22q Loss

“…Moreover, 2 noncoding RNAs involved in the regulation of EZH2, H19, and HOTAIR (39-41) turned out to be among the RNAs most significantly upregulated in FS-DFSP. This finding suggests that overexpression of H19 and HOTAIR, together with let-7 downregulation, all concur to induce EZH2 and, in turn, chromatin remodeling and mesenchymal transdifferentiation in FS-DFSP (19,(39)(40)(41). A role for epigenetic reprogramming in fibrosarcomatous transformation was also supported by the finding that 66 genes enriched in FS-DFSP versus DFSP are reported to undergo epigenetic regulation (11), and recent evidence is consistent with the involvement of chromatin remodeling in translocation-associated sarcomas (42).…”

“…In particular, the switch from DFSP to FS-DFSP was paralleled by an enrichment in genes belonging to the EMT gene signature, as defined by Gr€ oger and colleagues (15). The EMT program has been linked to aggressive tumor behavior, and modulation of mesenchymal traits toward a more undifferentiated state has been previously reported to play a pivotal role in sarcoma development and progression (16)(17)(18)(19)(20)(21). EMT is governed by a set of transcription factors, including TWIST1, SNAI2/SLUG, and ZEB1.…”

Fhit Regulates EMT Targets through an EGFR/Src/ERK/Slug Signaling Axis in Human Bronchial Cells

“…In addition, Vuoriluoto and colleagues previously demonstrated that Slug induces vimentin expression and migration in mammary cells (26). Vimentin, cell invasion, and migration were also found regulated by exogenous modulation of Slug in a leiomyosarcoma cell line (27).…”

ZEB2 Represses the Epithelial Phenotype and Facilitates Metastasis in Ewing Sarcoma

“…Several sarcomas are well differentiated and closely resemble what is thought to be the cell of origin (but could also be aberrantly differentiated), whereas others are poorly differentiated and the cell of origin remains uncertain. 8 A diverse group of sarcomas display features reminiscent of an EMT-MET, [9][10][11][12] suggesting that sarcomas may have some phenotypic plasticity.…”