FIGURE 2.

SK-N-AS cells degrade their DNA into HMW but not into LMW fragments. A, quantification of LMW-fragmented DNA in SK-N-AS, SH-SY5Y, and IMR-5 cells in a time-course experiment (3, 6, and 12 h) with 1 μm STP. Quantification was carried out as described under “Experimental Procedures.” The fluorescence values acquired were expressed as arbitrary units (F.A.U., fluorescence arbitrary units). All experiments were repeated at least three times. Values are expressed as the means ± S.E. Student's t tests were used to determine the statistical significance. p < 0.01 was considered to be significant. B, genomic DNA analysis of the samples obtained in A is shown. C, HMW fragmentation of the DNA in SH-SY5Y, SK-N-AS, and IMR-5 cells left untreated (0) or treated with 1 μm STP for 6 h is shown.