Epithelio-mesenchymal transitional attributes in oral sub-mucous fibrosis

Evaluating molecular attributes in association with its epithelial and sub-epithelial changes of oral sub-mucous fibrosis is meaningful in exploring the plausibility of an epithelio-mesenchymal transition (EMT) and malignant potentiality of this pathosis. In this study histopathological and histochemical attributes for basement membrane and connective tissue in biopsies of oral sub-mucous fibrosis (n = 55) and normal oral mucosa (n = 16) were assessed and expressions of p63, E-cadherin, β-catenin, N-cadherin and TWIST were analyzed immunohistochemically. The p63 and its isoforms (TA and ∆N), PARD3, E-cadherin and β-catenin were also assessed transcriptomically by q-PCR and EMT players like TWIST1, ZEB1, MMP9 and micro-RNA 205 were searched in gene expression microarrays. Oral epithelium demonstrating impairment in progressive maturation in oral sub-mucous fibrosis concomitantly experienced an increase in basement membrane thickness and collagen deposition along with alteration in target molecular expressions. In comparison to non-dysplastic conditions dysplastic stages exhibited significant increase in p63 and p63∆N expressions whereas, E-cadherin and β-catenin exhibited loss from the membrane with concurrent increase in cytoplasm. Further the N-cadherin and TWIST were gained remarkably along with the appearance of nuclear accumulation features of β-catenin. The microarray search had noticed the up-regulation of TWIST1, ZEB1 and MMP9 along with down regulation of micro-RNA 205. The simultaneous increase in basement membrane thickness and sub-epithelial collagen deposition were the plausible indicators for increased matrix stiffness with expected impact on oral epithelial functional homoeostasis. This was corroborated with the increase in expressions of epithelial master regulator p63 and its oncogenic isoform (∆N) along with membranous loss of E-cadherin (EMT hallmark) and its associate β-catein and gain of mesenchymal markers like N-cadherin and TWIST. These also became indicative for the induction of epithelial to mesenchymal transitional mechanism in oral sub-mucous fibrosis when connoted here with the relevant modulation in expressions of EMT regulators.