Fig. 4.
WNK2 expression is significantly down-regulated in primary high-grade but not low-grade meningiomas, and demethylating treatment reactivates expression in a silenced meningioma cell line. (A) Expression of WNK2 in normal leptomeninges and primary meningioma samples was determined by quantitative RT-PCR analysis and is expressed relative to the control gene, GusB. Gene expression values were derived from the equation ΔCt = (CtWNK2 – CtGusB) followed by (2−ΔCt) × 100. Columns indicate average of triplicates. An analysis of variance was performed among normal and different grades of tumors: p = 0.013 between normal and grade II; p = 0.0001 between normal and grade III; p = 0.019 between grade I and grade III. Comparisons of grade I or grade III tumors with grade II tumors were not statistically significant, likely due to the small number of grade II samples. Two independent experiments yielded similar results. (B) Expression of WNK2 in meningioma cell lines before and after treatment with 5-aza-2’-deoxycytidine as assessed by quantitative RT-PCR analysis. Abbreviations: U, untreated cells; ND, not detectable; A1 and A2, independent flasks of cells treated with 5 μM 5-aza-2’-deoxycytidine for 3 days. Columns indicate average of triplicates; error bars, standard deviation (SD).