Reactivation of the B-lineage genes in cHL-derived cell lines by treatment with 5-aza-dC. (A) Silencing of B-cell-specific genes in cHL cell lines. Transcriptional activity of B-lineage-specific genes was assayed by RT-PCR in Burkitt lymphoma (Namalwa and BJAB) and cHL (KM-H2, L1236 and L428) cell lines. (B) Reactivation of genes by 5-aza-dC treatment. 5 × 106 cells were seeded in complete medium at a density of 0.2 × 106 cells/mL. The next day, cells were treated with 1 μM 5-aza-dC for 24 hours. Then, cells were washed and resuspended in the fresh medium. After 72 hours cells were harvested and gene expression was assessed by RT-PCR. Whereas 35 PCR cycles were performed for most genes, signals for CD20, BCMA, and SYK could be detected only after 40 cycles in L428 cells. Cycles of amplification (25) were used for PBGD. PCR products were separated on the 1.5% agarose gel and visualized by EtBr staining. All experiments were done at least in triplicate.