BMI-1 activation is crucial in hTERT-induced epithelial–mesenchymal transition of oral epithelial cells
MetadataShow full item record
BMI-1 (B lymphoma Mo-MLV insertion region 1 homolog) has been reported to be over-expressed in cell immortalisation and the epithelial-mesenchymal transition (EMT) of cancer cells. The aim of this study is to study the roles of BMI-1 in the human telomerase reverse transcriptase (hTERT)-induced immortalisation and EMT. In this study, hTERT+-OME cells and hTERT+-HaCaT cells were acquired by viral transduction of hTERT to primary cultured oral keratinocytes and HaCaT cells (skin epidermal cells). siRNA transduction was used for the inhibition of BMI-1 expression. RT-PCR and Western blots were performed to detect the expressions of twist, vimentin, BMI-1, hTERT and p16INK4a in these cell lines. EMT was assessed by immunohistochemistry (expressions of cytokertin & vimentin), Western blots (expressions of Twist, vimentin & E-cadherin) and RT-PCR (expression of Twist). The results indicated that hTERT+-OME cells and hTERT+-HaCaT cells underwent EMT spontaneously with high expression of Twist. p16INK4a was silenced in both hTERT-transduced cells but could be detected in HaCaT cells. Moreover, BMI-1 was highly expressed in hTERT+-OME and hTERT+-HaCaT cells but was negative in HaCaT cells. When the expression of BMI-1 was blocked by siRNA transduction, the proliferations of hTERT+-OME and hTERT+-HaCaT cells were inhibited and the mono-spheroid colony formation of these hTERT-transduced cells was decreased. In addition, the expression of p16INK4a was regained while the expressions of EMT markers (twist and vimentin) were down-regulated in these two BMI-1 blocking cell lines. To conclude, this study suggests BMI-1 expression plays a role in hTERT-induced immortalisation and EMT.
Experimental and Molecular Pathology
© 2013 Elsevier Inc. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
Medical and Health Sciences not elsewhere classified