3-AP (Synonyms: 3-Aminopyridine-2-Carboxyaldehyde Thiosemicarbazone,NSC 663249,Triapine™)

Cell experiment:

An MTT assay is used to determine cell growth inhibition of CHO cells. Human leukemia K562 cells and K/VP.5 cells (a 26-fold etoposide-resistant K562-derived sub-line with decreased levels of topoisomerase IIα mRNA and protein) are maintained as suspension cultures in MEM containing 10% fetal calf serum (FCS). For growth inhibition assays, K562 and K/VP.5 cells are plated at a concentration of 1.5×105 cell/mL, and incubated 5 d with various concentrations of Dp44mT, 3-AP or vehicle (DMSO) for 48 h, after which cells are counted on a model ZBF Coulter counter. The IC50 growth inhibitory concentration for each cell line is calculated from a non-linear least-squares fit to a 2-parameter logistic equation[2].

Animal experiment:

Mice[3]Female BALB/c nu/nu mice are used at 8-10 weeks of age. Tumor cells in culture are harvested, and 107 cells are suspended in Matrigel and injected s.c. into the right flanks of mice. After engraftment, tumor size is measured by Vernier calipers. Tumor volumes (in cubic millimeters) are calculated. When tumor volumes reached 120 mm3, i.v. treatment began (day 0). Chelators (e.g., 3-AP) are dissolved in 15% propylene glycol in 0.9% saline and injected i.v. over 5 consecutive days per week for up to 7 weeks. Control mice are treated with vehicle alone.

References:

[1]. Martin LK, et al. A dose escalation and pharmacodynamic study of Triapine and radiation in patients with locally advanced pancreas cancer. Int J Radiat Oncol Biol Phys. 2012 Nov 15;84(4):e475-81.
[2]. Yalowich JC, et al. The anticancer thiosemicarbazones Dp44mT and Triapine lack inhibitory effects as catalytic inhibitors or poisons of DNA topoisomerase IIα. Biochem Pharmacol. 2012 Jul 1;84(1):52-8.
[3]. Whitnall M, et al. A class of iron chelators with a wide spectrum of potent antitumor activity that overcomes resistance to chemotherapeutics. Proc Natl Acad Sci U S A. 2006 Oct 3;103(40):14901-6.