PD184352 (CI-1040) is an ATP non-competitive MEK1/2 inhibitor with IC₅₀ of 17 nM in cell-based assays, 100-fold more selective for MEK1/2 than MEK5. Phase 2.

＞98%

Store at -20℃ for one year（Powder）；Store at 2-4℃ for two weeks；Store at -20℃ for six months after dissolution.

PD 184352；CI-1040；PD-184352

White to off-white solid

Ethanol ：12 mg/mL (25 mM)
DMSO ：47.9 mg/mL (100 mM)

MEK1 ,MEK2

CI-1040 treatment produces a reduction of pMAPK levels in multiple tumor cells including Colon 26, BX-PC3 pancreatic, A431 cervical, HT-29 colon, ZR-25-1 breast and SKOV-3 ovarian carcinomas. CI-1040 treatment doesn’t inhibit the phosphorylation of Jun kinase, p38 kinase or Akt, indicating CI-1040 specifically targets MEK. Inhibition of MAPK activation by CI-1040 prevents cell cycle progression and induces a G1 block. The IC₅₀ for inhibition of MEK1 by CI-1040 is 0.3 μM, 15-fold higher than the concentration required to inhibit the EGF-induced activation of ERK2 in Swiss 3T3 cells. These results indicate CI-1040 exerts its effects on cells by suppressing the activation of MKK1, and not by blocking its activity. 2 nM PD184352 inhibits the activation of MKK1 in Swiss 3T3 cells by 50%, while over 100-fold concentration of CI-1040 inhibits MEK1 in vitro. PD184352 also inhibits the Raf-catalysed phosphorylation of MEK1 without any effect on the Raf-catalysed phosphorylation of myelin basic protein. CI-1040 inhibits 86% of papillary thyroid carcinoma (PTC) cell growth with the RET/PTC1 rearrangement at 10μM compared with cells treated with DMSO only. CI-1040 shows potent inhibition to PTC cells (BRAF mutation) with GI50 of 52 nM, but low activity to RET/PTC1 rearrangement type with GI50 of 1.1 μM. A recent research indicates CI-1040 increases the apoptotic effect of BMS-214662 in a CML blast crisis cell line, K562, and in primary chronic phase CD34+ CML cells.

Oral dosing of CI-1040 impairs the growth of colon tumor xenografts of mouse and human with a wide dose range of 48-200 mg/kg per dose, but not of P388 leukemia. CI-1040 inhibits the tumor xenografts from PTC cells carrying a BRAF mutation with 31.3% reduction, carrying the RET/PTC1 rearrangement with 47.5% reduction than in untreated (vehicle) mice after 3 weeks of oral administration (300 mg/kg/d). No toxic effects are observed in any mice when they are treated with CI-1040. Transient exposure of mammary tumors to CI-1040 and UCN-01 causes tumor cell death in vivo and prolonged suppression of tumor regrowth. Combined treatment with CI-1040 (25 mg/kg) and UCN-01 (0.1-0.2 mg/kg) significantly reduces MDA-MB-231, and largely abolishs MCF7 tumor growth in implanted athymic mice, while either single treatment has no significant activity. The drug combination leads to profound tumor cell death which correlates with a reduction in the phosphorylation of ERK1/2 and the immuno-reactivity of Ki67 and of CD31.