Identification of furo[3', 2':3,4]naphtho[1,2-d]imidazole derivatives as orally active and selective inhibitors of microsomal prostaglandin E(2) synthase-1 (mPGES-1).

This study describes the synthesis and anti-inflammatory effects of furo[3', 2':3,4]naphtho[1,2-d] imidazole derivatives. Among these furo[3', 2':3,4]naphtho[1,2-d]imidazole derivatives, 2-(4-methoxyphenyl)furo [3', 2':3,4]naphtho[1,2-d]imidazole (12) exhibited a strong inhibitory activity against LPS-induced PGE(2) production, with an IC(50) value of 47 nM. Compound 12 is then further examined for its inhibitory effects in the protein expression of COX-2 and microsomal prostaglandin E(2) synthase-1 (mPGES-1) in Raw 264.7 cells. Our results indicate that compound 12 was capable against inhibiting LPS-induced mPGES-1 protein expression at a concentration of 1.0 µM and no inhibitory effect in COX-2 expression. The sepsis-induced PGE(2) production in rat serum decreased ~250% by the pretreatment of 12 at 10 mg/kg. These results are especially important since compound 12 exhibited good oral bioavailability (72%) and was not cytotoxic at a concentration of 10.0 µM. Therefore, compound 12 is a highly selective mPGES-1 inhibitor that can serve as a lead for the development of novel oral anti-inflammatory drug candidates.

ENU mutagenesis identifies mice with morbid obesity and severe hyperinsulinemia caused by a novel mutation in leptin.

BACKGROUND: Obesity is a multifactorial disease that arises from complex interactions between genetic predisposition and environmental factors. Leptin is central to the regulation of energy metabolism and control of body weight in mammals. METHODOLOGY/PRINCIPAL FINDINGS: To better recapitulate the complexity of human obesity syndrome, we applied N-ethyl-N-nitrosourea (ENU) mutagenesis in combination with a set of metabolic assays in screening mice for obesity. Mapping revealed linkage to the chromosome 6 within a region containing mouse Leptin gene. Sequencing on the candidate genes identified a novel T-to-A mutation in the third exon of Leptin gene, which translates to a V145E amino acid exchange in the leptin propeptide. Homozygous Leptin(145E/145E) mutant mice exhibited morbid obesity, accompanied by adipose hypertrophy, energy imbalance, and liver steatosis. This was further associated with severe insulin resistance, hyperinsulinemia, dyslipidemia, and hyperleptinemia, characteristics of human obesity syndrome. Hypothalamic leptin actions in inhibition of orexigenic peptides NPY and AgRP and induction of SOCS1 and SOCS3 were attenuated in Leptin(145E/145E) mice. Administration of exogenous wild-type leptin attenuated hyperphagia and body weight increase in Leptin(145E/145E) mice. However, mutant V145E leptin coimmunoprecipitated with leptin receptor, suggesting that the V145E mutation does not affect the binding of leptin to its receptor. Molecular modeling predicted that the mutated residue would form hydrogen bond with the adjacent residues, potentially affecting the structure and formation of an active complex with leptin receptor within that region. CONCLUSIONS/SIGNIFICANCE: Thus, our evolutionary, structural, and in vivo metabolic information suggests the residue 145 as of special function significance. The mouse model harboring leptin V145E mutation will provide new information on the current understanding of leptin biology and novel mouse model for the study of human obesity syndrome.

Synthesis and antiproliferative evaluation of certain indeno[1,2-c]quinoline derivatives. Part 2.

Certain indeno[1,2-c]quinoline derivatives were synthesized and evaluated for their antiproliferation, DNA binding affinity, and topoisomerases (topo I and topo II) inhibitory activities. The preliminary results are the following: (1) substituent of the aminoalkoxyimino side chain at C11 is important for antiproliferative activities in which the terminal amine preferred to be a tertiary or the cyclic five-membered pyrrolidino ring; (2) among the indeno[1,2-c]quinoline derivatives evaluated, (E)-6-hydroxy-9-methoxy-11H-indeno[1,2-c]quinolin-11-one O-2-(pyrrolidin-1-yl)ethyl oxime (8c) was found to be one of the most cytotoxic agents with a GI50 value of 0.84, 0.89, and 0.79 microM against SAS, A549, and BT483, respectively, which is more active than camptothecin; (3) substituent at C6 is crucial for the selective cytotoxicity in which the OH group is the most preferred while hydrogen or piperazine exhibited cytotoxicity on both cancer cells and Detroit-551; (4) a positive correlation of antiproliferative activity, DNA binding affinity, and topo I and topo II inhibitory activities has been observed for indeno[1,2-c]quinoline derivatives; (5) compound 8c induced DNA fragmentation may through caspase-3 activation, phosphorylation of the histone protein H2AX at Ser139 (gamma-H2AX), and PARP cleavage; (6) compound 8c demonstrated significant tumor regression in the human breast xenograft model; (7) indeno[1,2-c]quinoline derivatives are a new class of molecules that have the potential to be developed as dual topo I and topo II inhibitory agents.