Figure 3

(A) SLIT3 CpG island COBRA PCR products were cloned and sequenced from breast (MCF7, HCC712, HCC38 and HCC70) and colorectal (SW48) tumour cell lines. For each tumour cell line, several clones were sequenced and the methylation status for the first 30 CpGs is shown. White and black squares represent unmethylated and methylated CpGs, respectively. Partially filled squares represent partially methylated CpGs. (B) Expression of SLIT3 in methylated breast (MCF7) and colorectal (SW48) cell lines before and after treatment with the demethylating agent 5-aza-2′-deoxycytidine (5-aza dC). Gene expression was restored by 5-aza-dC (+) in methylated cell lines that lacked SLIT3 expression. GAPDH and the unmethylated glioma cell line T17 were used as positive controls to ensure RNA integrity and equal loading.