10,11-dehydrocurvularin exerts antitumor effect against human breast cancer by suppressing STAT3 activation.

Aberrant activation of signal transducer and activator of transcription 3 (STAT3) plays a critical role in many types of cancers. As a result, STAT3 has been identified as a potential target for cancer therapy. In this study we identified 10,11-dehydrocurvularin (DCV), a natural-product macrolide derived from marine fungus, as a selective STAT3 inhibitor. We showed that DCV (2-8 µM) dose-dependently inhibited the proliferation, migration and invasion of human breast cancer cell lines MDA-MB-231 and MDA-MB-468, and induced cell apoptosis. In the two breast cancer cell lines, DCV selectively inhibited the phosphorylation of STAT3 Tyr-705, but did not affect the upstream components JAK1 and JAK2, as well as dephosphorylation of STAT3. Furthermore, DCV treatment strongly inhibited IFN-γ-induced STAT3 phosphorylation but had no significant effect on IFN-γ-induced STAT1 and STAT5 phosphorylation in the two breast cancer cell lines. We demonstrated that the α, ß-unsaturated carbonyl moiety of DCV was essential for STAT3 inactivation. Cellular thermal shift assay (CETSA) further revealed the direct engagement of DCV with STAT3. In nude mice bearing breast cancer cell line MDA-MB-231 xenografts, treatment with DCV (30 mg·kg-1·d-1, ip, for 14 days) markedly suppressed the tumor growth via inhibition of STAT3 activation without observed toxicity. Our results demonstrate that DCV acts as a selective STAT3 inhibitor for breast cancer intervention.

Pristimerin protects against inflammation and metabolic disorder in mice through inhibition of NLRP3 inflammasome activation.

Excessive activation of NLRP3 inflammasome is associated with the pathogenesis of inflammatory diseases. Pristimerin (Pri) is a quinonoid triterpene derived from traditional Chinese medical herb Celastraceae and Hippocrateaceae. Pri has shown antifungal, antibacterial, antioxidant, and anticancer activities. In this study we investigated whether NLRP3 inflammasome was associated with the anti-inflammatory activity of Pri. We showed that Pri (0.1-0.4 µM) dose-dependently blocked caspase-1 activation and IL-1ß maturation in LPS-primed mouse bone-marrow-derived macrophages (BMDMs). Pri specifically inhibited NLRP3 inflammasome activation, had no visible effects on NLRC4 and AIM2 inflammasome activation. Furthermore, we demonstrated that Pri blocked the assembly of the NLRP3 inflammasome via disturbing the interaction between NEK7 and NLRP3; the α, ß-unsaturated carbonyl moiety of Pri was essential for NLRP3 inflammasome inactivation. In LPS-induced systemic inflammation mouse model and MSU-induced mouse peritonitis model, preinjection of Pri (500 µg/kg, ip) produced remarkable therapeutic effects via inhibition of NLRP3 inflammasome in vivo. In HFD-induced diabetic mouse model, administration of Pri (100 µg· kg-1 ·d-1, ip, for 6 weeks) reversed HFD-induced metabolic disorders via suppression of NLRP3 inflammasome activation. Taken together, our results demonstrate that Pri acts as a NLRP3 inhibitor, suggesting that Pri might be useful for the treatment of NLRP3-associated diseases.

[Effects of rapamycin on glucose-induced autophagy and apoptosis of corpus cavernosum smooth muscle cells in SD rats].

OBJECTIVE: To observe the effects of rapamycin on glucose-induced autophagy and apoptosis of corpus cavernosum smooth muscle cells (CCSMC) in SD rats. METHODS: After primary isolation, purification and identification, CCSMCs were treated with glucose at 5.6, 10, 20, 30 and 40 mmol/L for 48 hours. The autophagy flow was detected in the cells transfected with mCherry-GFP-LC3B double fluorescent adenovirus, the protein and mRNA expressions of autophagy-related gene 5 (ATG5), microtubule-associated protein 1 light chain 3 (LC3), P62 and Beclin-1 determined by Western blot and PCR and the apoptosis of the CCSMC measured by flow cytometry, followed by detection of the changes in the protein and mRNA levels of LC3, Beclin-1 and P62 and the apoptosis of the cells after 2-hour pretreatment with 600 nmol/L rapamycin and then 48-hour treatment with 40 mmol/L glucose. RESULTS: Autophagy was observed in the CCSMCs treated with different concentrations of glucose, the strongest in the 10 mmol/L group (P < 0.05) and then gradually decreasing with the increase of glucose concentration (P < 0.05). The apoptosis rate of the CCSMCs was remarkably increased in a concentration-dependent manner after treated with glucose (P < 0.01) though with no statistically significant difference between the 5.6 and 10 mmol/L groups (P = 0.302). After pretreatment with rapamycin, the expression of the LC3 protein and those of the Beclin-1 protein and mRNA were markedly up-regulated (P < 0.05), while those of the P62 protein and mRNA remarkably down-regulated (P < 0.05), indicating the enhancement of autophagy, and the apoptosis rate of the CCSMCs dramatically decreased (P < 0.01). CONCLUSIONS: In vitro culture of CCSMCs with glucose within a certain range of concentration can promote autophagy, inhibit the apoptosis and thus have a protective effect on the cells, but when the proper concentration exceeded, it may also reduce autophagy, promote the apoptosis and consequently affect the vitality and function of CCSMCs.

3-Phenyl-2-(prop-2-yn-yloxy)-1-benzofuro[3,2-d]pyrimidin-4(3H)-one.

In the title compound, C(19)H(12)N(2)O(3), the 1-benzofuro[3,2-d]pyrimidinone unit is approximately planar, the maximum deviation from the mean plane being 0.045 (1) Å. The attached phenyl ring makes a dihedral angle of 86.73 (6)° with the fused ring system. The packing of the mol-ecules in the crystal structure is mainly governed by C-H⋯π hydrogen-bonding inter-actions.

Roles of nitric oxide in protective effect of berberine in ethanol-induced gastric ulcer mice.

AIM: To investigate the protective effects of berberine on ethanol-induced gastric ulcer in mice. METHODS: Gastric ulcers were induced by oral ingestion of ethanol. Nitric oxide (NO) content was measured, and mRNA expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The ulcer index (UI) at 1 h, 2 h, 3 h and 6 h after oral administration of ethanol was 23.8+/-1.4, 23.3+/-2.2, 22.3+/-1.2 and 20.8+/-1.1, respectively. The UI in the berberine-treated groups (5 mg/kg and 50 mg/kg) was less than the control group. The content of NO in the control group was 73.3+/-7.3 microL/L, 94.0+/-9.2 microL/L, 109.6+/-6.4 microL/L and 138.2+/-10.2 microL/L in gastric juice and 5.8+/-1.1 micromol/g protein, 8.3+/-1.1 micromol/g protein, 9.8+/-1.1 micromol/g protein and 11.9+/-1.2 micromol/g protein in gastric tissue at 1 h, 2 h, 3 h and 6 h, respectively, after the oral administration of ethanol. The content of NO in the berberine-treated groups (5 mg/kg and 50 mg/kg) was higher than the control group at 1 h after the oral administration of ethanol (P<0.05), and was lower at 6 h (P<0.05). Analysis by RT-PCR showed that expression of eNOS was inhibited but iNOS expression was enhanced by ethanol. However, the expression of eNOS could be enhanced and iNOS expression could be inhibited by berberine (P<0.01). CONCLUSION: Berberine could significantly protect gastric mucosa from damage by ethanol. This effect may be related to the increased expression of eNOS mRNA and inhibited expression of iNOS mRNA.