The novel molecule 2-[5-(2-chloroethyl)-2-acetoxy-benzyl]-4-(2-chloroethyl)-phenyl acetate inhibits phosphoinositide 3-kinase/Akt/mammalian target of rapamycin signalling through JNK activation in cancer cells.

Screening a compound library of compound 48/80 analogues, we identified 2-[5-(2-chloroethyl)-2-acetoxy-benzyl]-4-(2-chloroethyl)-phenyl acetate (E1) as a novel inhibitor of the phosphoinositide 3-kinase/Akt pathway. In order to determine the mechanism of action of E1, we analysed the effect of E1 on components of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway. E1 demonstrated dose-dependent and time-dependent repression of Akt and mTOR activity in prostate and breast cancer cell lines, PC-3 and MCF-7, respectively. Inhibition of Akt and mTOR activity by E1 also coincided with increased c-Jun NH2-terminal kinase (JNK) phosphorylation. However, the mode of action of E1 is different from that of the mTOR inhibitor rapamycin. Proliferation and cell cycle analysis revealed that E1 induced cell cycle arrest and cell death in PC-3 and MCF-7 cells. Moreover, pretreatment of cancer cells with the JNK inhibitor SP600125 abolished the repression of Akt and mTOR activity by E1, indicating that the inhibition of Akt and mTOR by E1 is mediated through JNK activation. Consistently, E1 repressed Akt and mTOR activity in wild-type and p38-null mouse embryonic fibroblasts (MEFs), but not in MEFs lacking JNK1/2, and JNK-null MEFs were less sensitive to the antiproliferative effects of E1. We further showed that E1 can function cooperatively with suboptimal concentrations of paclitaxel to induce cell death in PC-3 and MCF-7 cells. Taken together, these data suggest that E1 induces cancer cell death through the JNK-dependent repression of Akt and mTOR activity and may provide a valuable compound for further development and research.

Quadruply hydrogen bonded cytosine modules for supramolecular applications.

In view of the range of properties required from supramolecular materials, there is clearly a need for new strong quadruple hydrogen bonded modules, which can be used in polymer or copolymer synthesis via the self- or hetero-association of complimentary units. A cytosine-based module has been prepared for supramolecular applications using a straightforward synthetic approach. The cytosine module was designed such that it does not undergo tautomeric changes observed with ureidopyrimidinones. The cytosine module was capable of forming quadruple hydrogen bonded assemblies both in solution and in the solid state, and the structure of the dimeric self-assembled unit was confirmed by single-crystal X-ray and solution NMR techniques. The dimerization constant was estimated to be greater than 9 x 106 M-1 in deuterated benzene. The capacity of the cytosine-based module to strongly hetero-associate with the ureidopyrimidinone module was demonstrated, and a supramolecular polymer of a bifunctional unit incorporating the cytosine module and PEG-based linker was described.

Highly stable cyclic dimers based on non-covalent interactions.

Highly stable cyclic dimers have been assembled through a combination of non-covalent interactions, including multiple hydrogen bonding, parallel stacking and hydrophobic shielding.

Ureidopyrimidinones incorporating a functionalizable p-aminophenyl electron-donating group at C-6.

[structure: see text] 2-Ureido-4-[1H]-pyrimidinones have been reported to dimerize via quadruple hydrogen bonding systems with dimerization constants >10(6) M(-1) in CDCl3. The dimerization constant, K(dim), is dependent on the solvent as well as the ring-substituents present, where previously alkyl (e.g., R1 = Me) and aromatic moieties (e.g., R1 = p-NO2C6H4, R1 = C6H2(OC13H27)3) have been incorporated at the C-6 position. To assess the influence of alternative, functionalizable, electron-donating groups on the dimerization motif and tautomeric distribution of isomers, the synthesis of compounds possessing aminophenyl functionality at the C-6 position has been achieved. NMR spectroscopy chemical shift analysis revealed that compound 2 (R1 = p-NH2C6H4, R2 = C6H13) existed as the 2-ureido-4-pyrimidinol dimeric DADA array in DMSO-d6, where a dimerization constant of 46 M(-1) was determined. This is the first time that a ureidopyrimidinone quadruple hydrogen bonding DADA array has been observed in pure DMSO, a highly polar solvent. The azo-derivative 5 of compound 2 was prepared which also adopted the pyrimidin-4-ol form in DMSO-d6. Compounds 7, 10 and 11 were then synthesized containing a more hydrophilic PEG unit in the lateral chain and the tautomeric distributions were determined.