NSC 663284 (Synonyms: Cdc25 Phosphatase Inhibitor II, DA30031, SPS8I1)

NSC 663284 is a potent, cell-permeable, and irreversible Cdc25 dual specificity phosphatase inhibitor, has an IC50 for Cdc25B2 of 0.21 μM. NSC 663284 exhibits mixed competitive kinetics against Cdc25A, Cdc25B(2), and Cdc25C with Ki values of 29, 95, and 89 nM, respectively[1].

NSC 663284 (3-100μM; 48 hours) has a mean IC50 value in the NCI 60 Cell human tumor panel of 1.5 ± 0.6 μM, has IC50 values of 0.2 μM in human breast cancer MDA-MB-435 and MDA-N cells, has an IC50 value of 1.7 μM in human breast MCF-7 cells in culture[1].NSC 663284 has relative IC50 values for Cdc25B2 (IC50=0.21 μM) are 20- and 450-fold lower than for VHR (IC50=4.0 μM) or PTP1B (IC50>4.0 μM), respectively[1].

NSC 663284 (intravenous injection; 2, 3, and 5mg/kg) inhibits the growth of subcutaneous human colon HT29 xenografts in SCID mice. After a single dose of 5 mg/kg, NSC 663284 is not detectable in plasma or tissues beyond 5 min. Following NSC 663284 treatment of tumor-bearing SCID mice, reduces glutathione concentrations in HT29 tumor are decreased to a greater extent and remained decreased for longer than the reduced glutathione concentrations in liver and kidneys[2].

References:
[1]. Lazo JS, et al. Discovery and biological evaluation of a new family of potent inhibitors of the dual specificity protein phosphatase Cdc25. J Med Chem. 2001 Nov 22;44(24):4042-9.
[2]. Guo J, et al. Pharmacology and antitumor activity of a quinolinedione Cdc25 phosphatase inhibitor DA3003-1 (NSC 663284). Anticancer Res. 2007 Sep-Oct;27(5A):3067-73.