Smoking and Mortality in Tianjin, China: A Death Registry-Based Case-Control Study, 2010-2014.

INTRODUCTION: We conducted a mortality case-control study to assess the risks of all-cause and major causes of death attributable to smoking in Tianjin from 2010 through 2014. The death registry-based study used data from The Tianjin All Causes of Death Surveillance System, which collects information routinely on smoking of the deceased in the death certificate of Tianjin Centers for Disease Control and Prevention. METHODS: Cases (n = 154,086) and controls (n = 25,476) were deaths at 35 to 79 years from smoking-related and nonsmoking-related causes, respectively. Mortality rate ratios (RRs) for ever smokers versus never smokers, with adjustment for sex, 5-year age group, education, marital status, and year of death, and smoking-attributed fractions were calculated. RESULTS: The RRs in men were 1.38 (95% confidence interval [CI], 1.33-1.43) for all causes and 3.07 (95% CI, 2.91-3.24) for lung cancer, and in women were 1.46 (95% CI, 1.39-1.54) and 4.07 (95% CI, 3.81-4.35). The smoking-attributed fractions for all causes and for lung cancer in men were 15.4% and 50.2%, respectively, and in women were 7.3% and 32.7%, respectively. Smoking annually caused an average of 3,756 (9.4%) deaths, mostly from lung cancer in men (47.4%) and women (66.9%). Women who started smoking before 30 had a higher RR (1.79; 95% CI, 1.63-1.97) than men who did so (1.48; 95% CI, 1.41-1.56). CONCLUSION: Lung cancer was the main cause of smoking-induced deaths in both sexes. Tobacco use is a major cause of premature deaths in men aged 35 to 79 years. Young women must be urged to not start smoking because they could have greater risk of all-cause and lung cancer deaths than men do.

Discovery of potent 1H-imidazo[4,5-b]pyridine-based c-Met kinase inhibitors via mechanism-directed structural optimization.

Starting from our previously identified novel c-Met kinase inhibitors bearing 1H-imidazo[4,5-h][1,6]naphthyridin-2(3H)-one scaffold, a global structural exploration was conducted to furnish an optimal binding motif for further development, directed by the enzyme inhibitory mechanism. First round SAR study picked two imidazonaphthyridinone frameworks with 1,8- and 3,5-disubstitution pattern as class I and class II c-Met kinase inhibitors, respectively. Further structural optimization on type II inhibitors by truncation of the imidazonaphthyridinone core and incorporation of an N-phenyl cyclopropane-1,1-dicarboxamide pharmacophore led to the discovery of novel imidazopyridine-based c-Met kinase inhibitors, displaying nanomolar enzyme inhibitory activity and improved Met kinase selectivity. More significantly, the new chemotype c-Met kinase inhibitors effectively inhibited Met phosphorylation and its downstream signaling as well as the proliferation of Met-dependent EBC-1 human lung cancer cells at submicromolar concentrations.

Investigation on the 1,6-naphthyridine motif: discovery and SAR study of 1H-imidazo[4,5-h][1,6]naphthyridin-2(3H)-one-based c-Met kinase inhibitors.

The 1,6-naphthyridine motif is a multivalent scaffold in medicinal chemistry presenting various bioactivities when properly substituted. By incorporating a cyclic urea pharmacophore into the 1,6-naphthyridine framework through conformationally constraining the 7,8-positions, the resulting 1H-imidazo[4,5-h][1,6]naphthyridin-2(3H)-one was identified as a new class of c-Met kinase inhibitor. A comprehensive SAR study indicated that an N-1 alkyl substituent bearing a terminal free amino group, a hydrophobic substituted benzyl group at the N-3 position and the tricyclic core were essential for retaining effective Met inhibition of the 1H-imidazo[4,5-h][1,6]naphthyridin-2(3H)-one chemotype. Further introduction of a 4'-carboxamide phenoxy group at the C-5 position significantly improved the potency. The best c-Met kinase inhibitory activity was exemplified by 2t with an IC(50) = 2.6 µM, which also displayed effective inhibition against TPR-Met phosphorylation and the proliferation of the BaF3-TPR-Met cells at low micromolar concentrations.

Discovery of a novel 5-carbonyl-1H-imidazole-4-carboxamide class of inhibitors of the HIV-1 integrase-LEDGF/p75 interaction.

Though much progress has been made in the inhibition of HIV-1 integrase catalysis, clinical resistance mutations have limited the promise of long-term drug prescription. Consequently, allosteric inhibition of integrase activity has emerged as a promising approach to antiretroviral discovery and development. Specifically, inhibitors of the interaction between HIV-1 integrase and cellular cofactor LEDGF/p75 have been validated to diminish proviral integration in cells and deliver a potent reduction in viral replicative capacity. Here, we have contributed to the development of novel allosteric integrase inhibitors with a high-throughput AlphaScreen-based random screening approach, with which we have identified novel 5-carbonyl-1H-imidazole-4-carboxamides capable of inhibiting the HIV-1 integrase-LEDGF/p75 interaction in vitro. Following a structure-activity relationship analysis of the initial 1H-imidazole-4,5-dicarbonyl core, we optimized the compound's structure through an industrial database search, and we went further to synthesize a selective and non-cytotoxic panel of inhibitors with enhanced potency.

Marine cyclotripeptide X-13 promotes angiogenesis in zebrafish and human endothelial cells via PI3K/Akt/eNOS signaling pathways.

Cyclotripeptide X-13 is a core of novel marine compound xyloallenoide A isolated from mangrove fungus Xylaria sp. (no. 2508). We found that X-13 dose-dependently induced angiogenesis in zebrafish embryos and in human endothelial cells, which was accompanied by increased phosphorylation of eNOS and Akt and NO release. Inhibition of PI3K/Akt/eNOS by LY294002 or L-NAME suppressed X-13-induced angiogenesis. The present work demonstrates that X-13 promotes angiogenesis via PI3K/Akt/eNOS pathways.

Four new aromatic allenic ethers from the fungus Xylaria sp. No. 2508.

Four new aromatic allenic ethers, (7E)-3-(4-buta-2,3-dienyloxy-3-methoxy-phenyl)-acrylic acid methyl ester (1), (7E)-3-[4-(4-buta-2,3-dienyloxy-benzyloxy)-phenyl]-acrylic acid methyl ester (2), 4-(4-buta-2,3-dienyloxy-benzyloxy)-benzoic acid methyl ester (3), (7E)-3-[4-(4-buta-2,3- dienyloxy-benzyloxy)-3-methoxy-phenyl]-acrylic acid methyl ester (4) were isolated from the fungus Xylaria sp. No. 2508. The structures of those compounds were determined by analysis of spectroscopic data, mainly 2D NMR experiments.

Discovery of novel 3-hydroxypicolinamides as selective inhibitors of HIV-1 integrase-LEDGF/p75 interaction.

Currently, three HIV-1 integrase (IN) active site-directed inhibitors are in clinical use for the treatment of HIV infection. However, emergence of drug resistance mutations have limited the promise of a long-term cure. As an alternative, allosteric inhibition of IN activity has drawn great attention and several of such inhibitors are under early stage clinical development. Specifically, inhibitors of IN and the cellular cofactor LEDGF/p75 remarkably diminish proviral integration in cells and deliver a potent reduction in viral replicative capacity. Distinct from the extensively studied 2-(quinolin-3-yl) acetic acid or 1H-indol-3-yl-2-hydroxy-4-oxobut-2-enoic acid chemotypes, this study discloses a new class of selective IN-LEDGF/p75 inhibitors without the carboxylic acid functionality. More significantly, 3-hydroxypicolinamides also show low micromolar inhibition against IN dimerization, providing novel dual IN inhibitors with in vitro therapeutically selective antiviral effect for further development. Finally, our shape-based ROCS pharmacophore model of the 3-hydroxypicolinamide class of compounds provides a new insight into the binding mode of these novel IN-LEDGF/p75 inhibitors.

Design of cell-permeable stapled peptides as HIV-1 integrase inhibitors.

HIV-1 integrase (IN) catalyzes the integration of viral DNA into the host genome, involving several interactions with the viral and cellular proteins. We have previously identified peptide IN inhibitors derived from the α-helical regions along the dimeric interface of HIV-1 IN. Herein, we show that appropriate hydrocarbon stapling of these peptides to stabilize their helical structure remarkably improves the cell permeability, thus allowing inhibition of the HIV-1 replication in cell culture. Furthermore, the stabilized peptides inhibit the interaction of IN with the cellular cofactor LEDGF/p75. Cellular uptake of the stapled peptide was confirmed in four different cell lines using a fluorescein-labeled analogue. Given their enhanced potency and cell permeability, these stapled peptides can serve as not only lead IN inhibitors but also prototypical biochemical probes or "nanoneedles" for the elucidation of HIV-1 IN dimerization and host cofactor interactions within their native cellular environment.

Repositioning HIV-1 integrase inhibitors for cancer therapeutics: 1,6-naphthyridine-7-carboxamide as a promising scaffold with drug-like properties.

Among a large number of HIV-1 integrase (IN) inhibitors, the 8-hydroxy-[1,6]naphthyridines (i.e., L-870,810) were one of the promising class of antiretroviral drugs developed by Merck Laboratories. In spite of its remarkable potency and efficacy, unfortunately upon completion of phase I clinical studies, development of L-870,810 was halted. Because of its desirable pharmacological and pharmaceutical properties we were intrigued to design novel analogues of L-870,810 with goals to (1) improve upon limitations of naphthyridine-7-carboxamides as antiviral agents and (2) to reposition their use as innovative cytotoxic agents for cancer therapeutics. Herein, we report on the design and synthesis of a series of 1,6-naphthyridine-7-carboxamides with various substitutions at the 5- and 8-positions. All the new 5-substituted-8-hydroxy-[1,6]naphthyridines were potent IN inhibitors and the 5-substituted-8-amino-[1,6]naphthyridines were significantly cytotoxic. Further optimization of the 5,8-disubstituted-[1,6]naphthyridines with structural variation on 7-carboxamide delivered novel compounds with significant cytotoxicity in a panel of cancer cell lines and effective inhibition against select oncogenic kinases.

Two new metabolites from the mangrove endophytic fungus no. 2106.

Two new metabolites, named no. 2106 A (1) and cyclo-(N-MeVal-N-MeAla) (2), have been produced by the endophytic fungus no. 2106 isolated from the seeds of the mangrove Avicennia marina in Hong Kong. The structures were elucidated by 2D NMR, HR-MS, and X-ray diffraction analyses.