Natural product toosendanin reverses the resistance of human breast cancer cells to adriamycin as a novel PI3K inhibitor.

Adriamycin (ADM) is a commonly used drug in clinical breast cancer treatment. However, some breast cancer types or breast cancers subjected to repeated ADM exposure develop strong resistance to ADM thus limiting its clinical efficacy. In this study, we found for the first time that toosendanin (TSN), a triterpenoid extracted from the traditional Chinese medicine Melia toosendan Sieb et Zucc, could successfully reverse adriamycin resistance in human breast cancer cells. Immunofluorescence and HPLC analysis demonstrated that TSN promoted adriamycin accumulation in breast cancer cells, especially in the nucleus. Furthermore, TSN could significantly reduce ABCB1 expression. We then found that TSN was capable of suppressing adriamycin-induced Akt phosphorylation, probably due to downregulation of the PI3K catalytic subunits P110α and P110ß, and inhibition of DNA-PKcs. Importantly, the inhibitory effect of TSN on PI3K P110α and P110ß expression was specifically observed in breast cancer cells but not in normal human cells. Moreover, TSN significantly potentiated the anti-cancer effect of ADM in the 4T1 breast cancer model and its inhibition rate was nearly 90%. Thus, TSN could be used as a novel PI3K inhibitor to reverse breast cancer resistance. The combination of ADM and TSN may represent a useful strategy for human breast cancer therapy.

Effect of NF-kappaB on inhibition of non-small cell lung cancer cell cyclooxygenase-2 by brucine / 中国中药杂志

<p><b>OBJECTIVE</b>To study the molecular mechanism of cyclooxygenase-2 (COX-2), one of effective ingredient of brucine, in inducing non-small cell lung cancer cell apoptosis.</p><p><b>METHOD</b>COX-2 promoter, transcription factor deletion mutants and COX-2 mRNA 3'-UTR-containing report plasmids were transfected with Renillia to non-small cell lung cancer A549 cell, in order to detect the activity of report gene luciferase and minimum cis-acting element of COX-2 promoter inhibited by brucine. The influence of brucine on IkappaB phosphorylation and the nuclear translocation of p65 were detected by immunoblotting assay.</p><p><b>RESULT</b>Brucine significantly suppressed LPS-induced COX-2 promoter activation, but revealed minor impact on COX-2 mRNA stability. NF-kappaB in the vicinity of COX-2 promoter-262 was an important cis-acting element of brucine for inhibiting the activity of COX-2 promoter. Brucine was found to inhibit the phosphorylation of IkappaBalpha as well as the nuclear translocation of p65.</p><p><b>CONCLUSION</b>Brucine can improve A549 cells apoptosis by inhibiting the activity of NF-kappaB and the subsequent COX-2 gene expression.</p>

Study on the effect of brucine on cyclooxygenase 2 in non-small cell lung cancer cells / 中国癌症杂志

Background and purpose:Brucine is one of the active components from Strychnos nux vomica,with signifi cant analgesic,anti-inflammatory and platelet-aggregating inhibitory properties.Due to its cytotoxic effect,the anti-tumor effect of brucine has increasingly been appreciated.In this study,we investigated the impact of brucine on A549 cells proliferation,apoptosis as well as the underlying mechanisms.Methods:MTT assay was used to examine the cell viability,flow cytometric analysis and fluorescent microscope were applied to examine cell apoptosis,ELISA method was used to examine the effect of brucine on PGE2 release from A549 cells and RT-PCR analysis was used to measure mRNA content,western blotting analysis was used to measure protein expression and luciferase activity was detected to examine the effect of brucine on COX-2 promoter activity.Results:Brucine was able to suppress the proliferation of A549 cells and induce cell apoptosis to time-dependent and dose-dependent manner.To understand the mechanisms,COX-2 was identifi ed to be an important target molecule involved in the apoptosis induced by brucine because brucine could suppress the COX-2 mRNA,protein expressions as well as PGE2 release in A549 cells in a timedependent manner.Furthermore,overexpression of COX-2 abrogated brucine-induced cell apoptosis,in contrast,when A549 cells were transfected with COX-2 siRNA,the apoptotic effect of brucine was dramatically enhanced.Further analysis revealed that brucine was able to suppress COX-2 transcriptional activation.Conclusion:Brucine was able to induce lung cancer apoptosis via downregulation of COX-2.

Fingerprint of dry stem in Dendrobium candidum by HPLC / 中草药

Objective To establish the fingerprint for the dry stem in Dendrobium candidum by RP-HPLC.Methods Kromasil○RKR100-5 C18 column(250 mm?4.6 mm,5 ?m) was used with a mixture of acetonitrile-0.4% phosphorus acid as mobile phase in a gradient mode and the data were analyzed with ″Computer Aided Similarity Evaluation″ software.Results The chemical constituents of D.candidum were optimally separated,among which 15 fingerprint peaks in common were confirmed.Conclusion This method is simple,accurate with good reproducibility,and can be used specifically for the quality control of D.candidum.

Study on the Chromatography Fingerprint of Radix Scrophulariae by RP-HPLC / 中药新药与临床药理

Objective To establish the chromatography fingerprint of Radix Scrophulariae by RP-HPLC.Methods HPLC was applied in this study.Kromasil KR100-5C18(4.6 mm? 250 mm,5 ? m)column and DAD detector were used with a mixture of methanol and 0.1 % methanoic acid as mobile phase in a gradient mode.Results The chemical substances of Radix Scrophulariae were optimally separated.Conclusion This method is simple,accurate with good reproducibility,thereby can be used specifically for the quality control of Radix Scrophulariae.