Figure 3.

Induction of ASS1 expression in 5-Aza-dC-treated lymphoma cells confers resistance to ADI-PEG20. Identically treated and 5-Aza-dC (5 μM)-untreated MyLa and SeAx cells were split into new flasks and treated with or without 500 ng/ml of ADI-PEG20 for a further 4 days. (a) ASS1 promoter methylation was analysed using MS-PCR and PCR products resolved on a 2% agarose gel. For each treatment, unmethylated (U) and methylated (M) reactions are shown. (b) ASS1 mRNA expression was quantified by qPCR. *P<0.05 represents statistical significance compared with untreated cells for each cell line. (c) Detection of ASS1 expression by western blotting using a Jurkat cell line as an ASS1-positive control. (d) At the end of the 12-day experiment, cells were counted using the Beckman Vi-Cell cell viability analyser. *P<0.05 represents statistical significance compared with untreated cells for each cell line. Error bars represent S.D. The data are representative of three or more independent experiments