Condensed tannins from Ulmus pumila L. leaves induce G2/M phase arrest and apoptosis via caspase-cascade activation in TFK-1 cholangiocarcinoma cells.

Condensed tannins the polyphenolic compounds that are widespread in plants have been proved to have antitumor potential. Here, we purified the bioactive condensed tannins from leaves of Ulmus pumila L. and explored their structural characteristics, antitumor effect on TFK-1 cholangiocarcinoma cells as well as the related potential mechanism. The UV-Vis, FT-IR spectroscopy, ESI-Full-MS, and thiolysis-HPLC-ESI-MS demonstrated that U. pumila condensed tannins (UCTs) consisted essentially of procyanidins with epicatechin as the main flavan-3-ol extension unit. The UCTs could significantly reduce the survival rate of human cholangiocarcinoma TFK-1, SK-CHA-1, and MZ-CHA-1 cells with the better inhibitory effect on TFK-1 cell proliferation. Flow cytometric assay showed that UCTs affected TFK-1 survival by G2/M phase arrest and inducing apoptosis in a dose-dependent manner. In addition, a total of 6592 differentially expressed genes (DEGs), consisting of 94 upregulated and 6498 downregulated DEGs, were identified between untreated and UCTs-treated TFK-1 cells using RNA-seq technology. Enrichment analysis based on the KEGG database revealed that these DEGs were closely associated with cell cycle and p53 apoptotic signaling pathways. Furthermore, qRT-PCR confirmed that treatment of UCTs to TFK-1 cells caused significant changes in the expression of cyclin E, cdc25 A, cytochrome c, caspase-3, and caspase-8. These results indicated that UCTs exhibited the growth inhibition effect on TFK-1 cells possibly via G2/M cell cycle arrest and activation of caspase-cascade to induce apoptosis, and had potential as an anti-cholangiocarcinoma drug for further development. PRACTICAL APPLICATIONS: Ulmus pumila L. as a valuable tree species has been widely used in fields of medicine and food. Condensed tannins, the polyphenolic compounds widespread in plants, have been proved to have antitumor potential and be safe to normal cells. In this study, the condensed tannins from leaves of U. pumila (UCTs) remarkably suppressed cholangiocarcinoma (CCA) cell viability possibly via G2/M cell cycle arrest and activation of caspase-cascade to induce apoptosis. The results provided evidence for the application of UCTs as a potential therapeutic drug for CCA tumor.

Curcumin induced the cell death of immortalized human keratinocytes (HaCaT) through caspase-independent and caspase-dependent pathways.

Curcumin is a diketone compound found in turmeric. It is used as food additives and spices, and has anti-proliferation and anti-cancer properties. However, the effect of curcumin on human keratinocytes (KCs) is still unclear. In this study, curcumin dramatically inhibited the cell growth of immortalized human KCs (HaCaT) and arrested the cells at the G2/M phase, with an apoptosis rate of 33.95% after 24 µM curcumin treatment. HaCaT cells showed changes in typical apoptotic morphology and the configuration of nuclear matrix-intermediate filaments (NM-IFs) after treatment with curcumin. We identified 16 differentially expressed nuclear matrix (NM) proteins, including apoptosis inducing factor (AIF) and caspase 3, by 2-DE and MALDI-TOF/TOF mass spectrometry. The expression of AIF decreased in the mitochondria and increased in the nucleus. Immunofluorescence assays showed that AIF was released from the mitochondria to the nucleus. AIF silencing and caspase inhibitor (z-vad-fmk) both lead to HaCaT cells being insensitive to apoptosis induced by curcumin. Meanwhile, after curcumin treatment, mitochondrial membrane depolarization led to cytochrome c release from the mitochondria to the cytoplasm, and the ratio of Bax to Bcl-2 in HaCaT cells was also increased, which subsequently initiated the activation of caspase-3. These results suggest that curcumin-induced apoptosis of HaCaT cells occurs not only through the caspase-dependent pathway but also through the caspase-independent pathway. This discovery enhances the development and utilization of curcumin and provides possible evidence for the treatment of proliferative skin diseases, including skin cancer.

Proanthocyanidins isolated from the leaves of Photinia × fraseri block the cell cycle and induce apoptosis by inhibiting tyrosinase activity in melanoma cells.

Tyrosinase is considered a molecular marker of melanoma, and few natural antitumor drugs targeting tyrosinase have been identified. In this study, proanthocyanidins (PAs) were isolated from the leaves of Photinia × fraseri and their structures were characterized by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the effects of antityrosinase activity were investigated. The results showed that the basic structural units of PAs are composed of catechin and epicatechin and that oligomer is the main component. PAs exhibited better antityrosinase activity via chelation of copper ions and by disturbing o-quinone production. Furthermore, analyses of the cell cycle, apoptosis rate, and regulation of melanin protein expression revealed preliminarily that PAs could affect melanin production by downregulating microphthalmia transcription factor (MITF) expression and by inhibiting the activities of tyrosinase and tyrosinase related protein 1 (TRP-1), leading to cell cycle arrest and apoptosis of melanoma cells. Collectively, our study demonstrated that PAs are potential tyrosinase inhibitors and have good antimelanoma effects. These findings provide a theoretical support for the application of tyrosinase inhibitors and for further drug development.

Inhibitory effects and molecular mechanism on mushroom tyrosinase by condensed tannins isolation from the fruit of Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow.

The structure of extracted condensed tannin (CT) from the fruit of Sour jujube (Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow) and the molecular mechanisms by which CT inhibits the activity of mushroom tyrosinase were investigated. The structure of CT was characterized by high performance liquid chromatography electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The kinetic assays were used to detect inhibition effect, type and mechanism. UV scanning, fluorescence quenching, copper interacting, o-quinone interaction and molecular docking assays were also used to reveal the molecular mechanisms by which CT inhibit tyrosinase. The results showed the structural units of CT containing afzelechin/epiafzelechin, catechin/epicatechin, and gallocatechin/epigallocatechin. Kinetic analysis showed that CT inhibits both the monophenolase and diphenolase activities of tyrosinase and exhibits reversible, mixed type mechanism. The fruit CT interacts primarily with the copper ions and specific amino acid residue (Asn191, Thr203, Ala202, Ser206, Met201, His194, His54, Glu182 and Ile42) in the active site of tyrosinase to disturb oxidation of substrates by tyrosinase. These results suggested the sour jujube fruit is a potential natural source of tyrosinase inhibitors, and has a potential to be used in food preservation, whitening cosmetics.

Effects of isoimperatorin on proliferation and apoptosis of human gastric carcinoma cells.

Resistance to apoptosis is an characteristic of cancer cells that serves a critical function in tumor development and represents a target for antitumor therapy. Isoimperatorin (ISOIM), a coumarin compound, exhibits antitumor functions in multiple types of tumor cells. However, its antitumor effects and molecular mechanisms with respect to gastric cancer have not been elucidated. The present study assessed the anti-proliferative and apoptotic effects of ISOIM on human BGC-823 gastric cancer cells and elucidated its underlying molecular mechanisms. Cell proliferation was evaluated using MTT assays. Analysis of cell morphology was performed by hematoxylin and eosin, Hoechst 33258 and acridine orange/ethidium bromide staining. In addition, cell cycle and apoptosis was evaluated using flow cytometry analysis; expression of apoptosis-associated proteins was studied by western blotting. The results of the present study revealed that ISOIM significantly inhibited cell proliferation by arresting the cell cycle at the G2/M phase and induced apoptosis by increasing Bcl-2-associated X (Bax) expression with a concomitant decrease in Bcl-2 expression, resulting in a decreased Bcl-2/Bax ratio compared with the control. In addition, ISOIM treatment also resulted in cytochrome c translocating from the mitochondria to the cytosol. Furthermore, caspase-3 was significantly activated in response to treatment with ISOIM, suggesting that apoptosis in BGC-823 cells is induced in the mitochondrial pathway. Taken together, the results of the present study indicate that ISOIM may significantly induce apoptosis in BGC-823 cells and that the pro-apoptotic mechanisms of ISOIM could be associated with the mitochondrial pathway.

Brief Sensation Seeking Scale for Chinese - Cultural Adaptation and Psychometric Assessment.

International behavioral research requires instruments that are not culturally-biased to assess sensation seeking. In this study we described a culturally adapted version of the Brief Sensation Seeking Scale for Chinese (BSSS-C) and its psychometric characteristics. The adapted scale was assessed using an adult sample (n=238) with diverse educational and residential backgrounds. The BSSS-C (Cronbach alpha=0.90) was correlated with the original Brief Sensation Seeking Scale (r = 0.85, p<0.01) and fitted the four-factor model well (CFI=0.98, SRMR=0.03). The scale scores significantly predicted intention to and actual engagement in a number of health risk behaviors, including alcohol consumption, cigarette smoking, and sexual risk behaviors. In conclusion, the BSSS-C has adequate reliability and validity, supporting its utility in China and potential in other developing countries.

Are urban low-income children from unplanned pregnancy exposed to higher levels of environmental tobacco smoke?

INTRODUCTION: The negative consequences of environmental tobacco smoke (ETS) in children have been well documented. Our objective is to assess whether children of unplanned pregnancies are at increased risk for ETS exposure. METHOD: Data were collected through interviews of mothers who accompanied their children to the Children's Hospital of Michigan, Detroit, Michigan. Associations of ETS exposure with unplanned pregnancy were analyzed using the χ2 test and stratified by maternal smoking status. Results from the bivariate analysis were further verified using a multiple logistic regression method to control for significant covariates. RESULTS: Among the sample of 399 children, 125 (31.3%) were born from unplanned pregnancies; 47.2% of the unplanned children and 25.6% of the planned children were exposed to ETS (χ2 = 18.4, p < .01). Unplanned children of non-smoking mothers also experienced higher levels of exposure to ETS compared with planned children (22.45% vs. 10.05%, χ(2) = 5.50, p < .05). The association remained significant after controlling for covariates (adjusted odds ratio = 2.45; 95% confidence interval = 1.03, 5.84; p < .05). DISCUSSION: Findings of this study suggest the importance of preventing ETS in urban children, particularly those from unplanned pregnancies.

Exposure to school and community based prevention programs and reductions in cigarette smoking among adolescents in the United States, 2000-08.

Smoking remains prevalent among US youth despite decades of antismoking efforts. Effects from exposure to prevention programs at national level may provide informative and compelling data supporting better planning and strategy for tobacco control. A national representative sample of youth 12-17 years of age from the National Survey on Drug Use and Health was analyzed. A 3-stage model was devised to estimate smoking behavior transitions using cross-sectional data and the Probabilistic Discrete Event System method. Cigarette smoking measures (prevalence rates and odds ratios) were compared between exposed and non-exposed youth. More than 95% of the sample was exposed to prevention programs. Exposure was negatively associated with lifetime smoking and past 30-day smoking with a dose-response relation. Reduction in smoking was related to increased quitting in 2000-02, to increased quitting and declined initiation in 2003-05, and to initiation, quitting and relapse in 2005-08. Findings of this analysis suggest that intervention programs in the United States can reduce cigarette smoking among youth. Quitting smoking was most responsive to program exposure and relapse was most sensitive to funding cuts since 2003. Health policy and decision makers should consider these factors in planning and revising tobacco control strategies.

Increased risk of cigarette smoking among immigrant children and girls in Hong Kong: an emerging public health issue.

Despite global progress in tobacco control, data are needed for subgroups with increased risk of tobacco use for more effective smoking prevention. Survey data from a random sample of 6,486 youth in grades 7, 8 and 9 were derived from the project Chinese Student Health Survey. Prevalence and hazards of smoking onset were compared by gender and immigrant status. Mediation analysis was used to assess factors that may mediate the impact of immigrant status on smoking. Immigrant students had a much higher risk of hazards of smoking initiation than non-immigrant students. Parental monitoring and parental smoking significantly mediated the effect of immigrant status on early smoking onset. In addition, gender differences in the prevalence of smoking and hazards of smoking onset in our study were smaller than those reported by others targeting non-Hong Kong Chinese youth. Findings of this study imply that immigrant children and girls in Hong Kong are at increased risk to tobacco use. Special attention should be paid to these subgroups for prevention intervention. Prevention intervention for immigrant children should address parental smoking and parental monitoring. Reduced gender difference in smoking among Hong Kong youth suggests an emerging trend for more Chinese girls on the Mainland to smoke along with the rapid socioeconomic development.