The epithelium to mesenchyme transition (EMT) is a process by which epitheliums lose their cell polarity and cell-cell adhesion, and gain migratory and invasive properties to become mesenchymal stem cells.
EMT is essential for numerous developmental processes including mesoderm formation and neural tube formation. EMT has also been shown to occur in wound healing, in organ fibrosis and in the initiation of metastasis for cancer progression.
An initial in silico data mining in a published ependymoma (EPN) patient series (GSE21687) revealed upregulation of EMT-Transcription factors (EMT-TFs) in tumor samples. Further, quantitative real time polymerase chain reaction (q-RT-PCR) based gene expression analysis of EMT-TFs in 96 EPNs showed significant up-regulation of SNAI1, SNAI2, ZEB1, and TWIST1 as compared to normal brain, associated with upregulation of CDH2/N-Cadherin and downregulation of CDH1/E-Cadherin. Although this was observed in varying degrees in all clinico-pathological-molecular subgroups of EPNs, it was most evident in supratentorial Ependymoma RELA fusion positive and in posterior fossa ependymomas. Immunohistochemistry performed in 60 of the above cases corroborated with gene expression patterns and immunopositivity for Snail, Slug, Zeb1, and Twist1 was observed in 80%, 80%, 81%, and 63% of all EPNs. Immunopositivity for N-Cadherin and E-Cadherin was observed in 76.6% and 2% cases respectively. Univariate Cox regression analysis showed that low expression of CDH1/E-Cadherin (P=.002) and high expression levels of CDH2/N-Cadherin (P<.001), SNAI1/Snail (P=.023), SNAI2/Slug (P<.001) and ZEB1 (P<.001) to be associated with shorter progression free survival.
Malgulwar et al., report for the first time the existence of EMT- like phenotype in EPNs. These factors could represent new prognostic and therapeutic targets in EPN 1).
Previous studies have estimated that microRNA (miRNA/miR) expression is associated with EMT via the regulation of the expression of target genes. miR 96 has been reported to exhibit a correlation with the EMT process. However, the functional role of miR‑96 and its mechanism in glioblastoma multiforme (GBM) remains to be completely elucidated. The objective of the present study was to investigate the functional role and mechanism of miR‑96 in the migration and invasion, in addition to proliferation, apoptosis and cell cycle distribution, of GBM. In the present study, the results suggested that the introduction of miR‑96 significantly inhibited the migration and invasion, in addition to proliferation and cell cycle progression, of GBM cells and promoted their apoptosis in vitro, leading to the hypothesis that miR‑96 may be a potential tumor suppressor. It was subsequently confirmed that astrocyte elevated gene‑1 (AEG‑1) was a direct target gene of miR‑96, using a luciferase assay and reverse transcription‑quantitative polymerase chain reaction analysis, in addition to western blotting. miR‑96 was observed to downregulate the expression of AEG‑1 at the mRNA and protein levels. Notably, AEG‑1 may suppress EMT by increasing the expression levels of E‑cadherin, an epithelial marker, and decreasing the expression levels of vimentin, a mesenchymal marker. Therefore, it was concluded that miR‑96 may impede the EMT process by downregulating AEG‑1 in GBM. Additionally, it was observed that inhibition of AEG‑1 led to a similar effect compared with overexpression of miR‑96 in GBM. In conclusion, the results of the present study demonstrated that miR‑96 may act as a tumor suppressor by regulating EMT via targeting of AEG‑1, suggesting that miR‑96 may be a potential biomarker and anticancer therapeutic target for GBM in the future 2).