Objective To investigate the relationship between aberrant methylation of SLC22A18 gene promoter and SLC22A18 expression in human glioma. Methods Thirty patients with glioma and 10 patients with craniocerebral injury performed decompression were chosen in our study;their tissue samples were prepared. Methylation-specific PCR (MSP) was used to detect the methylation status of SLC22A18 gene promoter;and Western blotting and RT-PCR were employed to measure the protein and mRAN expressions of SLC22A18 in these tissue samples. U251 cells were cultured in vitro with demethylating agent 5-aza-2-deoxycytidine (experimental group, 2μmol/L) and common medium (control group), resepectively;the re-expression of SLC22A18 in U251 cells was measured by Western blotting and cell growth suppression induced by 5-aza-2-deoxycytidine was also observed 3, 5 and 7 d after the culture. Results The methlylation of SLC22A18 gene promoter existed in glioma tissues of 15 patients (50%) but that did not exist in the tissues of patients with craniocerebral injury. The protein and mRAN expressions of SLC22A18 in the tissue samples of these 15 patients were significantly decreased as compared with those in patients with craniocerebral injury (P<0.05);cell counting of U251 cells in the experimental group on the 5th and 7th d of culture was significantly decreased as compared with that of those in the control group (P<0.05). On the 7ht d of culture, Western blotting indicated that the protein b expression level of SLC22A18 in the experimental group was obviously higher than that in the control group. Conclusion The aberrant methylation of SLC22A18 gene promoter plays a key role in down-regulating SLC22A18 expression, and demethylation agents can restore the SLC22A18 expression and suppress the growth of U251 cells.

Objective To study the expression of special AT-rich sequence-binding protein 1(SATB1) gene and its relationship with SLC22A18 protein expression in astrocytoma.Methods Fifty-six patients with astrocytomas (12 with grade Ⅰ,13 with grade Ⅱ,15 with grade Ⅲ,and 16 with grade Ⅳ),performed surgical excision in our hospitals from September 2006 to June 2010 and from September 2003 to June 2006,were chosen in our study; another 10 brain tissues from patients performed decompression operation resulting from cerebral hernia were selected as the controls.RT-PCR and Western blotting were used to detect the mRNA and protein expressions of SATB1.The SLC22A18 protein expression was detected by immunohistochemical assay.The relations between SLC22A18expressions and SA TB1 levels,and these two and the degree of malignancy were analyzed.Results RT-PCR and Western blotting revealed that positive mRNA and protein expressions were noted in 35patients with astrocytomas; the mRNA and protein expression rate and value of SATB1 in the astrocytoma tissues were significantly different among different grades of tumors (P＜0.05); the higher the malignancy grade,the higher mRNA and protein expression rate and value ofSA TB1; the protein expression value of SA TB1 had a positive correlation with the malignancy grade of tumors (r=0.987,P=0.000).And a few expressions of SA TB1 mRNA and protein were found in the tissues of controls.Immunohistochemical assay indicated that positive protein expression of SLC22A18 was noted in 19 astrocytoma tissues,and the protein expression rate of SLC22A18 in the astrocytoma tissues was significantly different among different grades of tumors (P＜0.05); the higher the malignancy grade,the lower expression of SLC22A18.And the protein expression of SLC22A18 was found in all the tissues of controls.The SATB1 expression rate in the tissues with negative SLC22A18 expression (81.1％) was significantly higher than that in the tissues with positive SLC22A18 expression (26.3％,P＜0.05).Conclusion SATB1 expresses in the astrocytoma tissues,indicating that it may play an important role in the pathogenesis of astrocytoma;up-regulation of SATB1 expression and dysfunction of SLC22A18 may play synergetic roles in the process of carcinogenesis of astrocytoma.