A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Background Epidermal growth factor receptor (EGFR) is both a driver oncogene and a therapeutic target in advanced head and neck squamous cell carcinoma (HNSCC). However, response to EGFR treatment is inconsistent and lacks markers for treatment prediction. This study investigated EGFR-induced epithelial-to-mesenchymal transition (EMT) as a central parameter in tumor progression and identified novel prognostic and therapeutic targets, and a candidate predictive marker for EGFR therapy response. Methods Transcriptomic profiles were analyzed by RNA sequencing (RNA-seq) following EGFR-mediated EMT in responsive human HNSCC cell lines. Exclusive genes were extracted via differentially expressed genes (DEGs) and a risk score was determined through forward feature selection and Cox regression models in HNSCC cohorts. Functional characterization of selected prognostic genes was conducted in 2D and 3D cellular models, and findings were validated by immunohistochemistry in primary HNSCC. Results An EGFR-mediated EMT gene signature composed of n = 171 genes was identified in responsive cell lines and transferred to the TCGA-HNSCC cohort. A 5-gene risk score comprising DDIT4, FADD, ITGB4, NCEH1, and TIMP1 prognosticated overall survival (OS) in TCGA and was confirmed in independent HNSCC cohorts. The EGFR-mediated EMT signature was distinct from EMT hallmark and partial EMT (pEMT) meta-programs with a differing enrichment pattern in single malignant cells. Molecular characterization showed that ITGB4 was upregulated in primary tumors and metastases compared to normal mucosa and correlated with EGFR/MAPK activity in tumor bulk and single malignant cells. Preferential localization of ITGB4 together with its ligand laminin 5 at tumor-stroma interfaces correlated with increased tumor budding in primary HNSCC tissue sections. In vitro, ITGB4 knock-down reduced EGFR-mediated migration and invasion and ITGB4-antagonizing antibody ASC8 impaired 2D and 3D invasion. Furthermore, a logistic regression model defined ITGB4 as a predictive marker of progression-free survival in response to Cetuximab in recurrent metastatic HNSCC patients. Conclusions EGFR-mediated EMT conveyed through MAPK activation contributes to HNSCC progression upon induction of migration and invasion. A 5-gene risk score based on a novel EGFR-mediated EMT signature prognosticated survival of HNSCC patients and determined ITGB4 as potential therapeutic and predictive target in patients with strong EGFR-mediated EMT

Interactome analysis reveals endocytosis and membrane recycling of EpCAM during differentiation of embryonic stem cells and carcinoma cells

Summary: Transmembrane epithelial cell adhesion molecule (EpCAM) is expressed in epithelia, carcinoma, teratoma, and embryonic stem cells (ESCs). EpCAM displays spatiotemporal patterning during embryogenesis, tissue morphogenesis, cell differentiation, and epithelial-to-mesenchymal transition (EMT) in carcinomas. Potential interactors of EpCAM were identified in murine F9 teratoma cells using a stable isotope labeling with amino acids in cell culture-based proteomic approach (n = 77, enrichment factor >3, p value ≤ 0.05). Kyoto Encyclopedia of Genes and Genomes and gene ontology terms revealed interactions with regulators of endosomal trafficking and membrane recycling, which were further validated for Rab5, Rab7, and Rab11. Endocytosis and membrane recycling of EpCAM were confirmed in mF9 cells, E14TG2α ESC, and Kyse30 carcinoma cells. Reduction of EpCAM during mesodermal differentiation and TGFβ-induced EMT correlated with enhanced endocytosis and block or reduction of recycling in ESCs and esophageal carcinoma cells. Hence, endocytosis and membrane recycling are means of regulation of EpCAM protein levels during differentiation of ESC and EMT induction in carcinoma cells

Additional file 4 of A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Additional file 4: Supplementary Table 3. Gene expression correlation with ITGB4 in the HPV-negativeTCGA cohort. Batch correlation analysis identified correlations of geneexpression with integrin beta 4 (ITGB4). Gene ID, Spearman correlation, andp-value are indicated for the top ten positively (co-regulated) and negativelycorrelated genes (counterregulated)

Additional file 2 of A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Additional file 2: Supplementary Table 1. EGFR-mediated EMT

Additional file 3 of A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Additional file 3: Supplementary Table 2. TCGA HPV- HNSC cohort

Additional file 5 of A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Additional file 5: Supplementary Table 4. SCC1 cell line: DEGs overlapping with EGFR-mediated EMT signature

Additional file 1 of A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer

Additional file 1: SupplementaryFigure 1. Copy number variation and expression of EGFR in Kyse30and FaDu cells. Supplementary Figure 2. GSEA of EGF- and EpEX-treated Kyse30and FaDu cells. Supplementary Figure 3. Over-representation analysis of genesof the EGFR-mediated EMT signature. SupplementaryFigure 4. Comparison ofEGFR-mediated EMT, pEMT, and EMT signatures. Supplementary Figure 5. Comparisonof EMT signatures for prognostic purposes.Supplementary Figure 6. ITGB4,ITGA6, LAMA3, LAMB3, and LAMC2 expression in HNSCC. Supplementary Figure 7. ITGB4expression in malignant and non-malignant single cells in different cancerentities. Supplementary Figure 8. ITGA6 expression in malignant andnon-malignant single cells in different cancer entities. Supplementary Figure 9. LAMA3expression in malignant and non-malignant single cells in different cancerentities. Supplementary Figure 10. LAMB3 expression in malignant andnon-malignant single cells in different cancer entities. Supplementary Figure 11. LAMC2expression in malignant and non-malignant single cells in different cancerentities. Supplementary Figure 12. ITGB4 expression in knockdown clonesof Kyse30 and FaDu cells. Supplementary Figure 13. Wound healing capacity of control andITGB4-knockdown cell lines. SupplementaryFigure 14. Tumor buddingintensities in HNSCC