1. Cell Cycle/DNA Damage
  2. DNA/RNA Synthesis

Triapine (Synonyms: 3-AP; PAN-811; OCX191; NSC663249)

Cat. No.: HY-10082 Purity: 98.32%
Handling Instructions

Triapine is a novel inhibitor of the M2 subunit of ribonucleotide reductase (RR), and is a potent radiosensitizer.

For research use only. We do not sell to patients.

Triapine Chemical Structure

Triapine Chemical Structure

CAS No. : 143621-35-6

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Free Sample (0.5-1 mg)   Apply now  
10 mM * 1 mL in DMSO USD 66 In-stock
Estimated Time of Arrival: December 31
5 mg USD 60 In-stock
Estimated Time of Arrival: December 31
10 mg USD 78 In-stock
Estimated Time of Arrival: December 31
25 mg USD 174 In-stock
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50 mg USD 312 In-stock
Estimated Time of Arrival: December 31
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  • Biological Activity

  • Protocol

  • Technical Information

  • Purity & Documentation

  • References


Triapine is a novel inhibitor of the M2 subunit of ribonucleotide reductase (RR), and is a potent radiosensitizer.

IC50 & Target

Ribonucleotide reductase (RR)[1]

In Vitro

Triapine is a potent derivative of α-heterocyclic carboxaldehyde thiosemicarbazone (HCT) that inhibits hRRM2 and p53R2 isoforms of the M2 subunit[1]. Triapine is thought to inhibit ribonucleotide reductase through its preformed iron chelate, rather than directly by removing iron from the active site. In cells containing less topoisomerase IIα fewer DNA strand breaks will be produced, and thus topoisomerase II poisons will be less inhibitory in the K/VP.5 cell line. The IC50s for Dp44mT growth inhibition are 48±9 nM and 60±12 nM, for K562 and K/VP.5 cells, respectively. The IC50s for Triapine growth inhibition are 476±39 nM and 661±69 nM for K562 and K/VP.5 cells, respectively[2]. PKIH and DpT Fe chelators show high antiproliferative activity against a range of tumor cell lines. Dp44mT shows the greatest antitumor efficacy with an IC50 that ranged from 0.005 to 0.4 μM. The average IC50 of Dp44mT over 28 cell types is 0.03±0.01 μM, which is significantly lower than that of Triapine (average IC50: 1.41±0.37 μM)[3].

In Vivo

Triapine causes a significant increase (1.7-fold) in splenic weight when expressed as a percentage of total body weight (1.02±0.06%; n=25) compared with control mice (0.6±0.03%; n=27). In the long-term group, a significant increase in heart weight is observed after Dp44mT (0.4 mg/kg per day) (0.8±0.06%; n=4) compared with control mice (0.5±0.01%; n=6). A significant decrease in the expression of Ndrg1, TfR1, and VEGF1 in the liver is noted for Dp44mT- and Triapine (12 mg/kg per day)-treated animals. The decreased expression could be related to the increased liver Fe in both Dp44mT- and Triapine-treated mice[3].

Clinical Trial
Solvent & Solubility
In Vitro: 

DMSO : ≥ 47 mg/mL (240.73 mM)

*"≥" means soluble, but saturation unknown.

Stock Solutions
Concentration Solvent Mass 1 mg 5 mg 10 mg
1 mM 5.1219 mL 25.6095 mL 51.2190 mL
5 mM 1.0244 mL 5.1219 mL 10.2438 mL
10 mM 0.5122 mL 2.5610 mL 5.1219 mL
*Please refer to the solubility information to select the appropriate solvent.
Cell Assay

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 (Minimal Essential Medium Alpha, Invitrogen) 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, Triapine 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].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Animal Administration

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., Triapine) 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.

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Molecular Weight








Powder -20°C 3 years
  4°C 2 years
In solvent -80°C 6 months
  -20°C 1 month

Room temperature in continental US; may vary elsewhere

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Cat. No.: HY-10082