[Expression and mechanism of Twist2 in glioma]

Objective: To investigate the significance of Twist2 in glioma and whether it is involved in the malignant transformation of glioma by epithelial-mesenchymal transition (EMT). Methods: Using immunohistochemical method detected the expression level of Twist2 in 60 cases of gliomas (including WHO grades Ⅱ, Ⅲ and Ⅳ, each for 20 cases) and 20 cases of non-tumor brain tissues. Real-time fluorescence quantitative PCR and Western blot were used to detect the expression level of Twist2 mRNA and protein in 61 cases of fresh glioma tissue (WHO grade Ⅱ 16 cases, Ⅲ 21 cases, Ⅳ 24 cases) and 12 cases of adjacent tissues, and the expression levels of E-cadherin, N-cadherin and vimentin were also investigated in fresh glioma tissue. Results: Immunohistochemistry results showed that the percentages of Twist2 expression in glioma was 90%(54/60) compared with 30%(6/20) in non-tumor brain tissues(P<0.01). The percentages of Twist2 expression were 75% (15/20), 95% (19/20), and 100% (20/20) in the WHO gradesⅡ, Ⅲ and Ⅳ gliomas, respectively. WHO grades Ⅳ and Ⅲ were significantly higher than that of WHO grade Ⅱ (P<0.01). There was no significant difference between WHO grade Ⅳand WHO Ⅲ glioma (P>0.05). Real-time fluorescence quantitative PCR and Western blot showed that the expression level of Twist 2 in gliomas was significantly higher than that in para-cancerous tissues (P<0.01), and those in WHO grades Ⅳ and Ⅲ gliomas were significantly higher than that in WHO grade Ⅱ glioma (P<0.01). There was no significant difference between WHO grade Ⅳand grade Ⅲ glioma (P>0.05). Detection of key protein expression in EMT by Western blot displayed that the expression of E-cadherin was negatively associated with Twist2 in glioma (r=-0.972, P<0.01). The expression of N-cadherin and vimentin was positively associated with Twist2 in glioma(r=0.971, P<0.01; r=0.968, P<0.01). Conclusions: The expression of Twist2 in human glioma is positively correlated with the malignant grade of glioma, which may be involved in the malignant progression of glioma by EMT.