Slug Is A Surrogate Marker of Epithelial to Mesenchymal Transition (EMT) in Head and Neck Cancer

Abstract

<jats:p>Background: Epithelial to mesenchymal transition (EMT) promotes therapy resistance in head and neck cancer (HNC) cells. In this study, EMT was quantified in HNC tumor samples by the cellular co-localization of cytokeratin/vimentin, E-cadherin/β-catenin and by Slug expression. Methods: Tissue samples from HNC patients were stained with antibody pairs against cytokeratin/vimentin and E-cadherin/β-catenin. Epithelial–mesenchymal co-localization was quantified using immunofluorescence multichannel image cytometry. Double positivity was confirmed using confocal microscopy. Slug was semi-quantified by 2 specialists and quantified by bright field image cytometry. Results: Tumor samples of 102 patients were investigated. A loss of E-cadherin positive cells (56.9 ± 2.6% vs. 97.9 ± 1.0%; p &lt; 0.0001) and E-cadherin/β-catenin double positive cells (15.4 ± 5.7% vs. 85.4 ± 1.2%; p &lt; 0.0001) was observed in tumor samples. The percentage of Slug positive cells was increased in tumor samples (12.1 ± 3.6% vs. 3.2 ± 2.6%; p = 0.001). Ordinal Slug scores judged by two specialists closely correlated with percentage of Slug-positive cells (Spearman’s rho = 0.81; p &lt; 0.001). Slug score correlated negatively with the percentage of E-cadherin positive cells (r = 0.4; p = 0.006), the percentage of E-cadherin/β-catenin positive cells (r = 0.5; p = 0.001) and positively with cytokeratin/vimentin positive cells (r = 0.4, p = 0.003). Conclusion: EMT can be assessed in HNC tumor probes by cytokeratin/vimentin co-expression and loss of E-cadherin/β-catenin co-expression. Slug score provides a convenient surrogate marker for EMT.</jats:p>

The Epithelial-Mesenchymal Transcription Factor Slug Predicts Survival Benefit of Up-Front Surgery in Head and Neck Cancer

“…The reaction was developed using a universal secondary antibody (Roche Ventana, Tucson, AZ, USA) and the DAB Map kit from Ventana ( Figure 1 ). The Slug status was categorized as positive if 10% or more of tumor cells were Slug positive [ 25 ]. A commercial in vitro diagnostic certified assay containing a ready-to-use prediluted mouse monoclonal antibody was used for p16 detection (CINtec ® Histology V-Kit, Roche Ventana, Tucson, AZ, USA).…”

“…NB100-417SS), and these reactions were also developed by using a universal secondary antibody (Roche Ventana) and the DAB Map kit from Ventana. Tumors were considered ERCC1 and CAIX positive if more than 30% of the cells showed positive staining [ 25 ].…”

“…EMT-related gene signatures are associated with radio- and chemotherapy resistance in patients with HNSCC [ 24 ]. We recently reported that EMT can be quantified in tumor samples from HNSCC patients using multichannel fluorescence image cytometry by evaluating the co-expression of epithelial and mesenchymal proteins in tumor cells [ 25 ]. The EMT-related transcription factor Slug was found to correlate with the relative count of tumor cells in EMT.…”

“…The EMT-related transcription factor Slug was found to correlate with the relative count of tumor cells in EMT. Based on these image cytometry data, HNSCC samples could be divided into Slug-positive and Slug-negative tumors using a cutoff of 10% Slug-positive tumor cells [ 25 ]. No Slug at all was detectable by immunohistochemistry (IHC) in 43/47 pharyngeal control tissues obtained during surgery for snoring or sleep apnea, and low expression was observed in the remaining control tissues ( Figure 1 ).…”

A computational systems biology approach identifies SLUG as a mediator of partial Epithelial-Mesenchymal Transition (EMT)

“…Investigation of EMT/MET in developmental contexts have helped identify the modulators of cancer cell plasticity [Nieto et al, 2016]. One of the key molecules that has been associated with hybrid E/M phenotypes in various developmental contexts is SLUG (SNAIL2) [Jolly et al, 2015]; resonating observations have been seen in clinical settings too recently [Steinbichler et al, 2020]. However, this association has been mostly at a phenomenological level.…”