Decitabine

In initial experiments, mice were treated with 2.5 mg/kg/mouse of Decitabine (5-aza-CdR) by intraperitoneal injection every day. The time point of 5-aza-CdR administration after tumor injection significantly affected tumor growth. If 5-aza-CdR was administered for the first time 11 days after tumor inoculation when tumor size already exceeded 1 cm2, and then for a period of eight days, a slight but not statistically significant decrease in tumor weight was detected compared to control mice [4]. At the 1 mg/kg dose tested, tetrahydrouridine (THU) increased Decitabine (DAC) plasma concentration (～ 10-fold) as compared to DAC alone. Severe toxicity occurred in females receiving high-dose 1 mg/kg DAC + THU, requiring treatment discontinuation at week 5 [5].

The IC50 values of Decitabine (5AZA) for both the HL-60 and KG1a leukemic cells for 72 and 96 h exposure were approximately 100 and 10 ng/ml, respectively. At drug concentrations of 1 ng/ml, KG1a cells were more sensitive to 5AZA than TSA or depsi; HL-60 cells were more sensitive to 5AZA than TSA and more sensitive to depsi than 5AZA [1]. Decitabine inhibited cell growth and induced G2/M arrest and apoptosis in EBVaGC cell lines. The expression of E-cadherin was up-regulated and cell motility was significantly inhibited in the cells treated with decitabine [2]. Exposure of HeLa cells to decitabine up-regulates the expression of several pyrimidine metabolic enzymes including DCTPP1, dUTPase, dCMP deaminase, and thymidylate synthase [3].

DMSO:11.4 mg/mL (50 mM),H2O:11.4 mg/mL (50 mM)

For cell cycle analysis, KARPAS-299 cells were incubated for 24 h with 1 μM of 5-aza-CdR in RPMI and grown for 4 days in fresh RPMI only. Then, 105–106 cells were suspended in 500 μl PI-buffer (0.1% Na–citrate dihydrate, 0.1% Triton X-100, 0.1% RNAse (DNAse free) in PBS). Propidium–iodide (ROTH, dissolved in PBS) was added to a concentration of 10 μg/ml and the cells were incubated for 30 min at 37 °C. The analysis was performed on a flow cytometer using the BD FACS Diva Software. Three independent samples of 5-aza-CdR treated and PBS controls were analyzed. Descriptive statistics for analysis are reported as mean ± SEM [4].

For xenografts, NOD.CB17-Prkdc?scid/NCrHsd (NOD/SCID, Harlan Laboratories) mice were used. KARPAS-299 human cells were grown as described above, dissolved in sterile PBS to a concentration of 1×107 cells/ml and inoculated subcutaneously (1×10^6 cells/injection) into the right and left flanks of the mice. Tumor range was followed measuring tumor length and tumor width with a calliper. Mice weighed approximately 25 g at the beginning of the therapy. 5-Aza-CdR was dissolved in sterile PBS and was administered intraperitoneally (i.p.). Each mouse received 2.5 mg/kg/mouse per treatment. Control mice were administered 100 μl of sterile PBS. Therapies were adjusted regarding start and duration of the treatment in order to obtain optimal treatment procedures. In schedule A, three mice were treated with 5-aza-CdR 11 days after inoculation, when tumor size was approximately 1 cm2. The control group contained two mice. The mice received 5-aza-CdR or PBS every day for eight days. In schedule B, two mice were treated with 5-aza-CdR three days after inoculation and three mice five days after inoculation when tumors were not or just palpable. 5-Aza-CdR was administered every other day for five times to each mouse. The control group contained two mice [4].