Methylation status and expression of SOCS3 in HBE and A549 cells. (a) Methylation status of SOCS3 in HBE and A549 cells, using the primer set designed in the exon 2, and detection of SOCS3 expression by western blot. The observed bands in lane M are methylated 159 bp products with methylation-specific primers and that in lane U are unmethylated 159 bp products with unmethylation-specific primers. Methylation was found in A549 cells but not in HBE cells and HBE cells expressed higher level of SOCS3. (b) The visible band in lane U appeared in A549 cells and SOCS3 was reactivated by the treatment of 5-aza-2'-deoxycytidine. The results are representative of three independent experiments.