b) Cisplatin was dissolved in DMSO as 50 mM solution prior to use. End concentration as indicated. 5 μM induce 50% of cell death [26]. 40 μM lead to 250 pg of Pt per pg of DNA, relating to 1 Pt per 1000 basepairs [27] c) MMS is stored at 4°C as a 12 M solution, end concentration as indicated. 300 μM applications inhibit 90% of DNA synthesis [28]. 100 μM induces irrepairable damage for exponentially growing cells. 200 μM induced damage can be repaired in quiescent cells [29]. MMS induces methylation of DNA by forming predominantly 3-methyladenine. This component should block DNA replication. MMS damage, induced with concentrations around 1mM, leads via Mut-genes to phosphorylation and enhanced expression of p53, at the cellular start of apoptosis induction [30,31]. d) HU is dissolved prior to use as a 1 M solution. End concentration in experiments is 10 mM, unless otherwise stated [32]. HU is used as an antimetabolite anticancer agent. Resistance to HU may result from a mutation of the ribonucleotide reductase, or it can involve other thus far unknown mechanism [33-37]. However, it immediately inhibits semi conservative replication, whereas repair is largely unaffected [38-40]. Thus, this S-phase inhibitor can distinguish repair from replication. e) araC is stored at -20°C as a 10 mM stock solution. End concentration is 10 mg/ml. f) Aph is dissolved in DMSO at 1mg/ml and stored at 4°C for less than 4 weeks. End concentration in experiments is 10 μg/ml [41]. g) ddT is stored in 10 mM Tris-HCl pH 8.0 at -20°C as a 10 mM stock solution. End concentration is 100 μM [42]. |
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| Table 1: Drugs and Chemicals. | |||||||||||||||||||||||||||
