Search

Background: In the present study, we investigated the role of p38-p38IP signaling in the inflammation-induced promotion of epithelial-to-mesenchymal transition (EMT) in Head and Neck Squamous Cell Carcinoma (HNSCC)., Methods: Quantitative RT-PCR, western blot analysis, spheroid modeling and immunohistochemical staining of human HNSCC tissue sections were used., Results: p38 inhibitor treated and p38 shRNA HNSCC cell lines demonstrate a significant upregulation in E-cadherin mRNA and a decrease in the mRNA expression of Snail. p38 binds to and stabilizes p38IP, a subunit of histone SPT3-TAF9-GCN5 acetyltransferase (STAGA), resulting in enhanced transcription of Snail. p38 shRNA HNSCC cell lines show a less invasive phenotype in a spheroid model. In clinical HNSCC samples, p38 interacting protein (p38IP) is significantly increased compared to adjacent normal tissue. An inverse relationship between p38, p38IP and E-cadherin is demonstrated., Conclusions: Herein we provide the first report that p38-p38IP is required for the Snail-induced E-cadherin down-regulation and cell invasion in HNSCC., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objective: The presence of regional metastases in patients with head and neck squamous cell carcinoma (HNSCC) is a common and adverse event associated with poor prognosis. The authors' recent work on human HNSCC tissues underlies Snail's role as a molecular prognostic marker for HNSCC. Snail positivity is significantly predictive of poorly differentiated, lymphovascular invasive, and regionally metastatic tumors. Here, the authors investigate the capacity of Snail to drive epithelial-mesenchymal transition (EMT) in human oral epithelial cell lines and its ability to confer drug resistance., Study Design: Snail was overexpressed in HNSCC and oral epithelial cell lines. Anchorage independent growth assays, wound healing assays, invasion and migration assays, spheroid modeling, and cell survival assays were performed., Setting: Academic tertiary medical center., Subjects and Methods: Snail overexpressing HNSCC (OSC, Tu212, Tu686) and oral epithelial cell lines (HOK 16-B, OKF-6) were evaluated using assays for wound healing, invasion and migration, 3-dimensional growth, Western blot, and immunofluorescence., Results: The overexpression of Snail in human HNSCC and oral epithelial cell lines drives EMT. The transfection of Snail confers the expression of a mesenchymal molecular signature, including downregulation of the epithelial adherens, such as E-cadherin and β-catenin, and induction of mesenchymal markers. Snail-overexpressing cell lines demonstrate rapid growth in Anchorage-independent growth assays, a decreased capacity to form tight spheroids, an increased resistance to erlotinib, and an increased capacity for invasion., Conclusion: Snail controls the mesenchymal phenotype and drives erlotinib resistance in HNSCC cells. Snail may prove to be a useful marker in predicting epidermal growth factor receptor inhibitor responsiveness.

Objective: Previous studies have shown Snail expression integral to the epithelial-mesenchymal transition during tumor progression. However, its behavior in clinical head and neck squamous cell carcinomas (HNSCCs) is yet undefined. We therefore sought to (1) investigate clinical and histopathologic characteristics of Snail-positive HNSCC and (2) understand the link between Snail and other commonly used HNSCC tumor markers., Study Design: A retrospective case-control study was conducted., Setting: This study was conducted in a large-scale academic center., Study Subjects: Of 51 consecutive HNSCC, 42 surgical resections were included., Methods: Two separate pathologists performed standard histopathologic reviews along with immunohistochemistries (Snail, E-cadherin, p16, epidermal growth factor receptor [EGFR]) and in situ hybridization (human papilloma virus [HPV]). Medical review for all cases was performed., Results: Twenty-two (52%) of 42 cases stained 4+ Snail (>75% staining). The remaining 20 cases were considered negative. Snail was strongly inversely related to E-cadherin expression (ρ = -0.69, P < .001), but statistically independent from HPV, p16, or EGFR expression. Snail(+) tumors were equally represented from each anatomic subsite. Snail(+) tumors were strongly associated with poor differentiation (P < .001) and basaloid classification (P = .004). Snail(+) tumors were also strongly associated with lymphovascular invasion (P = .02), but not perineural invasion. Ultimately, 11 (50%) of 22 of Snail(+) tumors demonstrated positive nodal metastasis and 11 (79%) of 14 node-positive cases were Snail(+) (P = .02)., Conclusion: This pilot study provides promising evidence of Snail' role as a molecular prognostic marker for HNSCC. Snail positivity is significantly predictive of poorly differentiated, lymphovascular invasive, as well as regionally metastatic tumors. Because Snail positivity appears independent of HPV, p16, and EGFR expression, Snail may prove to improve upon these markers' predictive limitations., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objectives: To determine the role of ZEB1 in the inflammation-induced promotion of the epithelial-mesenchymal transition (EMT) in head and neck squamous cell carcinoma (HNSCC)., Study Design: A molecular biology study. Real-time quantitative reverse-transcriptase polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical staining of human HNSCC tissue sections were used to determine how inflammation affects the transcriptional repressor, ZEB1., Setting: An academic hospital laboratory., Subjects and Methods: Relative ZEB1 RNA levels were determined by RT-PCR, and protein expression was evaluated in situ by immunohistochemical staining of human HNSCC tissue sections., Results: IL-1beta-treated HNSCC cell lines demonstrated a significant decrease in E-cadherin mRNA and an increase in the mRNA expression of the transcriptional repressor ZEB1. IL-1beta exposure led to enhanced ZEB1 binding at the chromatin level, as determined by chromatin immunoprecipitation assays (ChIP). An inverse relationship between ZEB1 and E-cadherin was demonstrated in situ by immunohistochemical staining of human HNSCC tissue sections., Conclusions: Our recent investigations indicate that inflammatory mediators are potent regulators of EMT in HNSCC. This is the first report indicating the role of ZEB1 in the inflammation-induced promotion of EMT in HNSCC. This newly defined pathway for transcriptional regulation of E-cadherin in HNSCC has important implications for targeted chemoprevention and therapy., (Copyright 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.)

Purpose: As a transcriptional repressor of E-cadherin, Snail has predominantly been associated with epithelial-mesenchymal transition, invasion, and metastasis. However, other important Snail-dependent malignant phenotypes have not been fully explored. Here, we investigate the contributions of Snail to the progression of non-small cell lung cancer (NSCLC)., Experimental Design: Immunohistochemistry was done to quantify and localize Snail in human lung cancer tissues, and tissue microarray analysis was used to correlate these findings with survival. NSCLC cell lines gene-modified to stably overexpress Snail were evaluated in vivo in two severe combined immunodeficiency murine tumor models. Differential gene expression between Snail-overexpressing and control cell lines was evaluated using gene expression microarray analysis., Results: Snail is upregulated in human NSCLC tissue, and high levels of Snail expression correlate with decreased survival (P < 0.026). In a heterotopic model, mice bearing Snail-overexpressing tumors developed increased primary tumor burden (P = 0.008). In an orthotopic model, mice bearing Snail-overexpressing tumors also showed a trend toward increased metastases. In addition, Snail overexpression led to increased angiogenesis in primary tumors as measured by MECA-32 (P < 0.05) positivity and CXCL8 (P = 0.002) and CXCL5 (P = 0.0003) concentrations in tumor homogenates. Demonstrating the importance of these proangiogenic chemokines, the Snail-mediated increase in tumor burden was abrogated with CXCR2 blockade. Gene expression analysis also revealed Snail-associated differential gene expression with the potential to affect angiogenesis and diverse aspects of lung cancer progression., Conclusion: Snail upregulation plays a role in human NSCLC by promoting tumor progression mediated by CXCR2 ligands.

Purpose: Inflammatory cytokines have been implicated in the progression of head and neck squamous cell carcinoma (HNSCC). Herein we investigate the mechanisms by which interleukin-1beta (IL-1beta) might contribute to Epithelial-Mesenchymal Transition (EMT) in HNSCC., Experimental Design: We evaluated the effect of IL-1beta on the molecular events of EMT in surgical specimens and HNSCC cell lines. We examined the correlation with tumor histologic features, and a SCID xenograft model was used to assess the effects of Snail overexpression., Results: Cyclooxygenase-2 (COX-2)-dependent pathways contribute to the modulation of E-cadherin expression in HNSCC. An inverse relationship between COX-2 and E-cadherin was shown in situ by double immunohistochemical staining of human HNSCC tissue sections. Treatment of HNSCC cells with IL-1beta caused the downregulation of E-cadherin expression and upregulation of COX-2 expression. This effect was blocked in the presence of COX-2 small hairpin RNA. IL-1beta-treated HNSCC cell lines showed a significant decrease in E-cadherin mRNA and an increase in the mRNA expression of the transcriptional repressor Snail. IL-1beta exposure led to enhanced Snail binding at the chromatin level. Small hairpin RNA-mediated knockdown of Snail interrupted the capacity of IL-1beta to downregulate E-cadherin. In a SCID xenograft model, HNSCC Snail-overexpressing cells showed significantly increased primary and metastatic tumor burdens., Conclusions: IL-1beta modulates Snail and thereby regulates COX-2-dependent E-cadherin expression in HNSCC. This is the first report indicating the role of Snail in the inflammation-induced promotion of EMT in HNSCC. This newly defined pathway for transcriptional regulation of E-cadherin in HNSCC has important implications for targeted chemoprevention and therapy.