KLF4, Slug and EMT in Head and Neck Squamous Cell Carcinoma

Abstract

Epithelial to mesenchymal transition (EMT) is clinically relevant in head and neck squamous cell carcinoma (HNSCC). We hypothesized that EMT-transcription factors (EMT-TFs) and an anti-EMT factor, Krüppel-like-factor-4 (KLF4) regulate EMT in HNSCC. Ten control mucosa and 37 HNSCC tissue samples and three HNSCC cell lines were included for investigation of EMT-TFs, KLF4 and vimentin at mRNA and protein levels. Slug gene expression was significantly higher, whereas, KLF4 gene expression was significantly lower in HNSCC than in normal mucosa. In the majority of HNSCC samples, there was a significant negative correlation between KLF4 and Slug gene expression. Slug gene expression was significantly higher in human papilloma virus (HPV) negative HNSCC, and in tumor samples with irregular p53 gene sequence. Transforming-growth-factor-beta-1 (TGF- β1) contributed to downregulation of KLF4 and upregulation of Slug. Two possible regulatory pathways could be suggested: (1) EMT-factors induced pathway, where TGF-β1 induced Slug together with vimentin, and KLF4 was down regulated at the same time; (2) p53 mutations contributed to upregulation and stabilization of Slug, where also KLF4 could co-exist with EMT-TFs.

SLUG‐related partial epithelial‐to‐mesenchymal transition is a transcriptomic prognosticator of head and neck cancer survival

“…6 and Fig. S7), which is in accordance with reports from others [34][35][36]. A recent meta-analysis of the prognostic value of EMT-TFs in HNSCC disclosed that Twist, Snail, SLUG, and Zeb1 correlated with significantly poorer OS [37].…”

Opposing Roles of Wild-type and Mutant p53 in the Process of Epithelial to Mesenchymal Transition

“…Low expression of p53 together with low expression of E-cadherin may act as an independent unfavorable prognostic sign in oral squamous cell carcinoma ( Fan et al, 2013 ). For head and neck cancer cells, it was shown that the negative status of p53 contributed to increased Slug expression ( Ingruber et al, 2021 ). The p53 and Slug interaction was also noted for the embryonic development.…”

Mitochondrial dysfunction and epithelial to mesenchymal transition in head neck cancer cell lines

“…GAPDH was used as a housekeeping gene, and relative quantities of the transcripts were calculated by pairwise differences of threshold cycles (δCT) of the gene of interest and the loading control housekeeping gene 30 . For the final analysis, we used the relative quantification and related the PCR signal in the cells to a control reference gene expression level 12 . The identity of the PCR products of genes was confirmed by Sanger sequencing by Microsynth Austria (Vienna, Austria) 12 .…”

“…These traits are also characteristic of epithelial to mesenchymal transition (EMT) 8 – 10 , a complex, variable, and context-specific cellular program that enables carcinoma cells to suppress epithelial characteristics in favour of mesenchymal differentiation 11 . In cancer, EMT is usually incomplete and reversible, resulting in coexpression of epithelial and mesenchymal markers 12 . EMT-associated reprogramming is regulated by various transcription factors, including SNAI1, SNAI2, ZEB, and TWIST 13 , 14 .…”

“…The OCR/ECAR ratio and xCT expression are inversely correlated. EMT was assessed by gene expression analysis of SNAI2 and vimentin, flow cytometric analysis of vimentin/cytokeratin double-positive cells, and holotomographic microscopy 12 .…”