Figure 4

The combination of 5-Aza-CdR and castration decreased the global gene methylation levels in human prostate cancer xenograft mouse models. (A) The expression of DNMT1, 3a and 3b was measured by qRT-PCR and normalized to the expression of GAPDH in each sample of mice (n = 6). (B) A schematic illustration of COBRA LINE-1. DNA was extracted from the xenograft tissues, treated with bisulfite, and subjected to PCR. LINE-1 methylation level was assessed by TasI-TaqI double digestion within the 160-bp amplicon. The methylated amplicons (TaqI positive) yielded two 80-bp DNA fragments, whereas the unmethylated amplicons (TasI positive) yielded 63- and 97-bp fragments. (C) COBRA LINE-1 of xenograft tissues. The percentage of methylation is listed above each test. The data are the mean ± SD of one representative experiment. Similar results were obtained in three independent experiments. *P < 0.05 and **P < 0.01 compared to the controls.