Matrine reduces proliferation of human lung cancer cells by inducing apoptosis and changing miRNA expression profiles.

Matrine, a main active component extracted from dry roots of Sophora flavecens , has been reported to exert antitumor effects on A549 human non-small lung cancer cells, but its mechanisms of action remain unclear. To determine effects of matrine on proliferation of A549 cells and assess possible mechanisms, MTT assays were employed to detect cytotoxicity, along with o flow cytometric analysis of DNA content of nuclei of cells following staining with propidium iodide to analyze cell cycle distribution. Western blotting was performed to determined expression levels of Bax, Bcl-2, VEGF and HDAC1, while a microarray was used to assessed changes of miRNA profiles. In the MTT assay, matrine suppressed growth of human lung cancer cell A549 in a dose- and time- dependent manner at doses of 0.25-2.5 mg/ml for 24h, 48h or 72h. Matrine induced cell cycle arrest in G0/G1 phase and decreased the G2/M phase, while down-regulating the expression of Bcl2 protein, leading to a reduction in the Bcl-2/Bax ratio. In addition, matrine down regulated the expression level of VEGF and HDAC1 of A549 cells. Microarray analysis demonstrated that matrine altered the expression level of miRNAs compared with untreated control A549 cells. In conclusion, matrine could inhibit proliferation of A549 cells, providing useful information for understanding anticancer mechanisms.

The influence of the total flavonoids of Hedysarum polybotry on the proliferation, cell cycle, and expressions of p21Ras and proliferating cell nuclear antigen gene in erythroleukemia cell line K562.

OBJECTIVE: To investigate the effect of total flavonoids of Hedysarum polybotry on the proliferation, cell cycle, and expressions of p21(Ras) and proliferating cell nuclear antigen (PCNA) gene in erythroleukemia cell line K562. METHODS: The effect of total flavonoids of Hedysarum polybotry on K562 cell line survival was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) reduction assay. The time- and dose-dependent manner was also observed. The cell cycle and apoptosis were analyzed with flow cytometry (FCM). The immunocytochemistry method was applied to quantitatively analyze the effects of flavonoids of Hedysarum polybotry on changes p21(Ras) and PCNA gene expressions. RESULTS: Flavonoids of Hedysarum polybotry (20-100 µg/mL) significantly inhibited the proliferation of K562 cells in a time- and dose-dependent manner. After K562 cells were cultured for 48 h, total flavonoids of Hedysarum polybotry had no significant effect on the apoptosis of K562 cells but showed significantly inhibition (P<0.01), indicating that total flavonoids of Hedysarum polybotry could induce K562 cells arrested at G(0)/G(1) and G(2)/M phases. Compared with the control group, p21(Ras) and PCNA gene expressions were decreased significantly in K562 cells treated with total flavonoids of Hedysarum polybotry (40 and 80 µg/mL, respectively) for 48 h. CONCLUSION: The inhibitory effect on proliferation of K562 cells was observed in the groups treated with flavonoids of Hedysarum polybotry, which might be related to cells arresting.

Actions of genistein on contractile response of smooth muscle isolated from guinea pig gallbladder.

BACKGROUND: Defective contractile motility of the gallbladder is an important factor for gallstone formation. Estrogen might increase the risk of gallstones and cholecystitis, and estradiol inhibits the contractile activity of isolated strips of guinea pig gallbladder. The potential risks associated with hormone replacement therapy (HRT) include symptomatic gallstones. Phytoestrogen have been used to treat menopause syndromes by replacing traditional estrogen. This experiment aimed to determine the effects of the phytoestrogen genistein on the contractile response of smooth muscle strips isolated from guinea pig gallbladder and its possible mechanism of action. METHODS: Guinea pigs were sacrificed to remove the whole gallbladder. Two or three smooth muscle strips were cut longitudinally. Each strip was suspended in a tissue chamber containing Krebs solution. After 2 hours of equilibration, contractile response indexes were recorded. Different concentrations of genistein were added to the chamber and the contractile responses were measured. Each antagonist was added 2 minutes before genistein to study possible mechanisms. The effect of genistein on calcium-dependent contraction curves and biphasic contraction in calcium-free Krebs solution were measured. RESULTS: Genistein decreased the resting tension dose-dependently, and reduced the mean contractile amplitude and frequency in gallbladder strips. Ranitidine partly inhibited the effect of genistein, but methylene blue, Nomega-nitro-L-arginine, and propranolol hydrochloride did not influence this action. Genistein had no significant effects on calcium-dependent contraction. Genistein reduced the first contraction induced by acetylcholine chloride, but did not affect the second contraction caused by CaCl2. CONCLUSIONS: Genistein relaxed smooth muscle isolated from the gallbladder of guinea pigs and this might contribute to the formation of gallstones. The inhibitory action might be related to H2 receptors and the release of intracellular Ca2+ from sarcoplasmic reticulum. Replacing traditional estrogen with phytoestrogen to treat menopause syndromes may increase the risk of gallstone formation.