In this cell system, EP300 led to up-regulation of mesenchymal (vimentin, Snail, Slug, Zeb1) and stemness (ALDH<sup>+</sup> and CD44<sup>high</sup>/CD24<sup>low</sup>) markers, increases in migration, invasion, anchorage-independent growth and drug resistance.
All three miRs in this cluster target EP300, a transcriptional activator of E-cadherin, resulting in cells acquiring a phenotype characteristic of cells undergoing epithelial-to-mesenchymal transition (EMT), including an increase in both cell motility and invasion, as well as the ability to proliferate after treatment with doxorubicin.
In OSCC samples, 65% of those with deep tumour invasion (adventitia) and 63% samples with metastasis revealed p300 promoter methylation (p<0.05). p300 mRNA expression was observed in 19.0% (4/21) of methylated tumours and 58.6% (17/29) of unmethylated tumours (p = 0.005).