Endorsing cellular competitiveness in aberrant epithelium of oral submucous fibrosis progression: neighbourhood analysis of immunohistochemical attributes

Abstract

Epithelial abnormality during the transformation of oral submucous fibrosis (OSF) into oral squamous cell carcinoma has been well studied and documented. However, the differential contribution of atrophy and hyperplasia for malignant potentiality of OSF is yet to be resolved. Existing diagnostic conjectures lack precise diagnostic attributes which may be effectively resolved by substantiation of specific molecular pathology signatures. Present study elucidates existence of cellular competitiveness in OSF conditions using computer-assisted neighbourhood analysis in quantitative immunohistochemistry (IHC) framework. The concept of field cancerization was contributory in finding correspondence among neighbouring cells of epithelial layers with reference to differential expression of cardinal cancer-related genes [c-Myc (oncogene), p53 (tumour suppressor), and HIF-1α (hypoxia regulator)] which are known to be important sensors in recognizing cellular competitive interface. Our analyses indicate that different states of OSF condition may be associated with different forms of competitiveness within epithelial neighbouring cells which might be responsible to shape the present and future of the pre-malignant condition. Analytical findings indicated association of atrophic epithelium with stress-driven competitive environment having low c-Myc, high-p53, and stable HIF-1α (the looser cells) which undergo apoptosis. Whereas, the cells with high c-Myc (winner cells) give rise to hyperplastic epithelium via possible mutation in p53. The epithelial dysplasia plausibly occurs due to clonal expansion of c-Myc and p53 positive supercompetitor cells. Present study proposes quantitative IHC along with neighbourhood analysis which might help us to dig deeper on to the interaction among epithelial cell population to provide a better understanding of field cancerization and malignant transformation of pre-malignancy.

Loss of oral mucosal stem cell markers in oral submucous fibrosis and their reactivation in malignant transformation

“…CBP augments histone H3 acetylation in the PAI-1 promoter, activating PAI-1 transcription. 16 Thus, Wt-p53 is expressed intensely in the basal layer of the atrophic epithelium in OSF compared to the hyperplastic epithelium, 13 suggesting that Wt-p53 plays a key role in the initiation of fibrosis and epithelial atrophy by reducing stemness.…”

“…17,18 Notably, atrophic epithelium in OSF shows high p53 levels, low c-MYC expression and stable hypoxia-inducible factor (HIF) expression. 13 The clonal expansion and evolution of dysplasia is the outcome of high c-MYC activity and Mut-p53 expression. 13 The downregulation of Oct-4 in the atrophic epithelium of OSF in contrast to the normal epithelium 4 (Fig.…”

“…13 The clonal expansion and evolution of dysplasia is the outcome of high c-MYC activity and Mut-p53 expression. 13 The downregulation of Oct-4 in the atrophic epithelium of OSF in contrast to the normal epithelium 4 (Fig. 1a) and its rebound expression in the malignant transformation of OSF suggests altered stemness (Fig.…”

“…While Rajendran et al 7 was the first to propose downregulated stem cell activity in OSF, it was subsequently confirmed to be due to the adverse effects of nitric oxide and areca nut-associated carcinogens on basal stem cells. 11 The reduced stem cell activity in atrophic OSF was evidenced by a decrease in the expression of proliferative/stem cell markers, such as Ki-67, Cyclin-D1 (CCND-1) and c-MYC, 10,13 and an increase in their expression in the malignant transformation of OSF. 10,13 The OM-SCMs involved in molecular signalling pathways include keratins 5/14, 15, 19, α 6 β 4 -integrin + CD71 − , β 1 -integrin, collagen IV, p75 NGFR , stage-specific embryonic antigen 1 (SSEA1), CD24, CD44 (CD44H), CD71, CD117 (c-kit), CD133, melanomaassociated chondroitin sulfate proteoglycan (MCSP), Nestin, p63, octamer-binding transcription factor-3/4 (Oct-3/4), Nanog, SOX2, ABCG-2, ALDH1 and Bmi-1 (Supplementary Information (SI)).…”

“…2,5,6 Several reports suggest downregulated basal stem cell activity as a tipping event triggering epithelial atrophy in OSF. 4,[7][8][9][10][11][12][13][14] Limited scientific evidence supports a rebound amplification of stem cell activity in the epithelium transitioning from atrophic OSF to oral epithelial dysplasia (OED) and eventually to OSCC. A comprehensive assessment of oral mucosal stem cell markers (OM-SCMs) in relation to the progression of OSF, OED and OSCC is performed in this review (Figs.…”