Study on the methylation status of MGMT in meningiomas and its effect on the growth and metastasis of meningioma cells / 中国医师杂志

ABSTRACT

Objective:To investigate the methylation status of O6-methylguanine-DNA methyltransferase (MGMT) in meningioma tissue and its effect on the growth and metastasis of human meningioma cell line IOMM-Lee cells.Methods:The specimens of 34 patients with meningioma were collected. Methylation-specific polymerase chain reaction (MSP) method was used to detect MGMT methylation in meningioma tissue and normal brain tissue; immunohistochemical staining was used to detect the expression of MGMT in meningioma tissue and normal brain tissue. The cultured human glioma cell line IOMM-Lee cells were divided into blank control group (normal cultured IOMM-Lee cells), negative control group (empty vector virus transfected IOMM-Lee cells) and RNAi lentivirus transfection group (transfected with RNAi lentivirus vector to down-regulate the expression of MGMT). The expression of MGMT in IOMM-Lee cells was silenced by RNAi technology. The expression levels of MGMT mRNA and protein in cells were detected by real-time fluorescence quantitative PCR and Western blot. The proliferation activity of cells was detected by cell counting kit-8 (CCK-8) test, the colony forming ability was detected by cell clone formation test, and the invasion and migration ability of cells in each group were detected by Transwell test and cell scratch test.Results:The methylation of MGMT in meningioma tissue reached 88.23% (30/34). MGMT methylation was not detected in normal brain tissue; the staining intensity of MGMT in meningioma tissue was significantly higher than that in normal brain tissue. Compared with the blank control group and the negative control group, the relative expression of MGMT mRNA and protein in IOMM-Lee cells of the RNAi lentiviral transfection group were significantly decreased (all P<0.05). After 24, 48 and 72 hours of transfection, the proliferation activity of IOMM-Lee cells decreased significantly (all P<0.05), with reduced number of cell clone formation and cell invasion (all P<0.05). The rate of scar healing decreased significantly ( P<0.05). Conclusions:MGMT is mostly hypermethylated in human meningiomas. Silencing the expression of MGMT in meningiomas can inhibit the growth and metastasis of meningiomas.