Our results indicate that photon irradiation increases the migration of glioblastoma cells in vitro. qPCR and immunoblotting experiments in two different glioblastoma cell lines (U-373 MG and U-87 MG) with different malignancy revealed that both Slit2 and Robo1 are significantly lower expressed in the cell populations with the highest motility and that the expression was reduced after irradiation.
Slit homolog 2 (SLIT2), myelin and lymphocyte protein gene (MAL) and insulin-like growth factor binding protein 7 (IGFBP7) are known to be hypermethylated in various malignancies.
Methylation of SLIT2 and TMEFF2 was more frequently detected in the mucosa of IBD patients at high risk of dysplasia or cancer (15/20) than patients at low risk (32/63) (P = 0.05 and P = 0.03, respectively).
Using methylation-specific polymerase chain reaction analysis, the methylation status of the SLIT2 promoter was measured in tumour tissue and serum samples from 36 patients with ovarian cancer and in matched serum samples from 25 controls without cancer.
However, the role of Slit2 in vitro remains controversial, and the biological significance of Slit2 expression in cancer cell invasion in vivo has not yet been determined.
These findings implicate SLIT2 promoter methylation in the pathogenesis of both paediatric and adult cancers and suggest that further investigations of SLIT2 in other tumour types should be pursued.
Furthermore, re-expression of SLIT2 inhibited the growth of cancer cell lines so that SLIT2 appears to function as a novel tumour suppressor gene (TSG).