Molecular profiling of tumour budding implicates TGFβ‐mediated epithelial–mesenchymal transition as a therapeutic target in oral squamous cell carcinoma

Abstract

Although tumour budding is an adverse prognostic factor for many cancer types, the molecular mechanisms governing this phenomenon are incompletely understood. Therefore, understanding the molecular basis of tumour budding may provide new therapeutic and diagnostic options. We employ digital image analysis to demonstrate that the number of tumour buds in cytokeratin-stained sections correlates with patients having lymph node metastases at diagnosis. The tumour bud count was also a predictor of overall survival, independent of TNM stage. Tumour buds and paired central tumour areas were subsequently collected from oral squamous cell carcinoma (OSCC) specimens, using laser capture microdissection, and examined with RNA sequencing and miRNA-qPCR arrays. Compared with cells from the central parts of the tumours, budding cells exhibited a particular gene expression signature, comprising factors involved in epithelial-mesenchymal transition (EMT) and activated TGFβ signalling. Transcription factors ZEB1 and PRRX1 were up-regulated concomitantly with the decreased expression of mesenchymal-epithelial (MET) transcription factors (eg OVOL1) in addition to Krüppel-like factors and Grainyhead-like factors. Moreover, miR-200 family members were down-regulated in budding tumour cells. We used immunohistochemistry to validate five markers of the EMT/MET process in 199 OSCC tumours, as well as in situ hybridization in 20 OSCC samples. Given the strong relationship between tumour budding and the development of lymph node metastases and an adverse prognosis, therapeutics based on inhibiting the activation of TGFβ signalling may prove useful in the treatment of OSCC.

RETRACTED: miR‐655 suppresses epithelial‐to‐mesenchymal transition by targeting Prrx1 in triple‐negative breast cancer

“…Prrx1 regulates the differentiation of mesenchymal precursors and plays a central role in pancreatic regeneration and carcinogenesis 31. More importantly, Prrx1 promotes metastasis through the induction of the EMT in hepatocellular carcinoma and breast cancer 32. Here, Prrx1 was identified as an important downstream target of miR‐655.…”

Combining discovery and targeted proteomics reveals a prognostic signature in oral cancer

“…Altogether, the tumor microenvironment is in fact increasingly complex and mediates the signaling crosstalk of different tumor cell and stromal cell types and tumor regions 12–14,32 . Previous proteomic studies of oral cancer have used LDM to evaluate tumor cells of epithelial origin 29,33–35 and Jensen et al 17 analyzed the ITF and the central area of the OSCC tumor; however, they did not evaluate the stroma from each region.…”

“…Grading systems based on the ITF 4,16 have demonstrated reliable predictive value for OSCC prognosis, thus highlighting the importance of this area for molecular profiling and for the identification of potential biomarkers, as it is considered a key region in the dynamic progression of malignant tumors 12,13,17 . The presence of neoplastic islands, classified as large or small according to the number of cells in the ITF, has been described as the most aggressive pattern compared to tumors with a more uniform growth pattern, as tumor invasion occurs in a more widespread manner as cellular islands or single cells 4 .…”

Predictive Significance of Tumor Depth and Budding for Late Lymph Node Metastases in Patients with Clinical N0 Early Oral Tongue Carcinoma

“…Almangush et al reported the combination of tumor budding (B) and a tumor depth (D) as a BD model for the prognostication of early oral tongue carcinoma [17]. The correlation between tumor budding and epithelial-mesenchymal transition has also been suggested [14,18,19]. As tumor budding was thought to be a microscopic indicator of tumor invasiveness, we focused on this feature for predicting late lymph node metastasis in this study.…”