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. 2012 Jul 5;3(7):e342. doi: 10.1038/cddis.2012.83

Figure 2.

Figure 2

ASS1 status in normal and malignant lymphoid cell lines and sensitivity to ADI-PEG20. (a) Normal immortalised lymphoblastoid and lymphoma cell lines were screened for ASS1 mRNA and protein expression by qPCR and western blotting, respectively; ASS1 methylation was assessed using MS-PCR: HRC57, NcNc (normal lymphoblastoid cell lines); DoHH2, WSU, Karpas-422, RL2261 (FL cell lines); SUDHL-6, SUDHL-8, SUDHL-16 (DLBCL cell lines); Ramos (Burkitt's lymphoma cell line); and SeAx, MyLa (CTCL cell lines). The Jurkat leukaemia cell line was used as a positive control for ASS1 expression. A good correlation was observed between the methylation status of cell lines and the corresponding levels of ASS1 mRNA and protein. (b) Cells were treated with the arginine-depleting drug ADI-PEG20 and harvested after 2 or 4 days. Cell counting and viability were determined using the Beckman Vi-Cell cell viability analyser. Increasing concentrations of ADI-PEG20 (concentration range: 0–500 ng/ml) decreased the number of ASS1-negative lymphoma viable cells with no change in the viability of ASS1-positive cell lines by day 4. For each cell line, the viability was expressed as a percentage of untreated cells at day 2; *P<0.05 represents statistical difference to the baseline untreated cells for each cell line at each time point; §P<0.05 represents statistical difference at day 4 compared with day 2 for each cell line at each ADI-PEG20 concentration. The data are representative of three independent experiments. Error bars represent S.D.