1,7‐Bis(4‐hydroxyphenyl)‐4‐hepten‐3‐one from Betula platyphylla induces apoptosis by suppressing autophagy flux and activating the p38 pathway in lung cancer cells

Betula platyphylla (BP) is frequently administered in the treatment of various human diseases, including cancers. This study was undertaken to investigate the pharmacological function of the active components in BP and the underlying mechanism of its chemotherapeutic effects in human lung cancer cells. We observed that BP extracts and 1,7‐bis(4‐hydroxyphenyl)‐4‐hepten‐3‐one (BE1), one of the components of BP, effectively decreased the cell viability of several lung cancer cell lines. BE1‐treated cells exhibited apoptosis induction and cell cycle arrest at the G2/M phase. Further examination demonstrated that BE1 treatment resulted in suppression of autophagy, as evidenced by increased protein expression levels of both LC3 II and p62/SQSTM1. Interestingly, the pharmacological induction of autophagy with rapamycin remarkably reduced the BE1‐induced apoptosis, indicating that apoptosis induced by BE1 was associated with autophagy inhibition. Our data also demonstrated that BE1 exposure activated the p38 pathway resulting in regulation of the pro‐apoptotic activity. Taken together, we believe that BE1 is a potential anticancer agent for human lung cancer, which exerts its effect by enhancing apoptosis via regulating autophagy and the p38 pathway.     

异乌药内酯对人乳腺癌MCF-7细胞的生长抑制作用及其机制研究

目的研究异乌药内酯对人乳腺癌MCF-7细胞生长的抑制作用及其作用机制。方法体外培养MCF-7细胞,分为对照组及不同浓度异乌药内酯处理组。采用MTT实验检测异乌药内酯对MCF-7细胞增殖的影响;采用流式细胞术和TUNEL染色法检测异乌药内酯对MCF-7细胞周期、线粒体膜电位及细胞凋亡的影响;采用Western blotting法检测与细胞凋亡密切相关的蛋白表达情况。结果异乌药内酯以时间和剂量依赖性抑制MCF-7细胞增殖、促进细胞凋亡;能够将MCF-7细胞周期阻滞在G2/M期,诱导线粒体膜电位去极化;上调cleaved Caspase-3和促凋亡蛋白Bax表达,抑制抗凋亡蛋白Bcl-2表达,诱导MCF-7细胞的凋亡。结论异乌药内酯对MCF-7细胞的增殖抑制作用呈剂量和时间依赖性,其作用机制可能是通过线粒体途径诱导细胞凋亡。     

Luteoloside attenuates anoxia/reoxygenation‐induced cardiomyocytes injury via mitochondrial pathway mediated by 14‐3‐3η protein

Ischemia/reperfusion (I/R) injury is the major cause of acute cardiovascular disease worldwide. 14‐3‐3η protein has been demonstrated to protect myocardium against I/R injury. Luteoloside (Lut), a flavonoid found in many Chinese herbs, exerts myocardial protection effects. However, the mechanism remains unclear. We hypothesize that the cardioprotective role of Lut is exerted by regulating the 14‐3‐3η signal pathway. To investigate our hypothesis, an in vitro I/R model was generated in H9C2 cardiomyocytes by anoxia/reoxygenation (A/R) treatment. The effects of Lut on cardiomyocytes with A/R injury were assessed by determining the cell viability, lactate dehydrogenase levels, intracellular reactive oxygen species levels, mitochondrial permeability transition pores (mPTP) openness, caspase‐3 activity, and apoptosis rate. The effects on protein expression were tested using western blot analysis. Lut attenuated A/R‐induced injury to cardiomyocytes by increasing the expression of 14‐3‐3η protein and cell viability; decreasing levels of lactate dehydrogenase, reactive oxygen species, mPTP openness, caspase‐3 activity, and low apoptosis rate were observed. However, the cardioprotective effects of Lut were blocked by AD14‐3‐3ηRNAi, an adenovirus knocking down the intracellular 14‐3‐3η expression. In conclusion, to our knowledge, this is the first study to demonstrate that Lut protected cardiomyocytes from A/R‐induced injury via the regulation of 14‐3‐3η signaling pathway.     

α‐Hederin induces the apoptosis of gastric cancer cells accompanied by glutathione decrement and reactive oxygen species generation via activating mitochondrial dependent pathway

α‐Hederin, a monodesmosidic triterpenoid saponin, exhibited promising antitumor potential against a variety of human cancer cell lines. However, few related studies about effects of α‐hederin on gastric cancer are available. Herein, our results showed that α‐hederin significantly inhibited the proliferation of gastric cancer cells and arrested the cell cycle in G1 phase in vitro (p < .05). Further research of the potential mechanism reflected that α‐hederin could induce intracellular glutathione decrement, adenosine triphosphate level, and mitochondrial membrane potential variation via inducing reactive oxygen species accumulation during the apoptosis of gastric cancer cells. Moreover, the detection of mitochondrial and cytosol proteins with apoptosis‐inducing factor, apoptosis protease activating factor‐1, and cytochrome C showed an increase in the cytosol, followed by a decrease of Bcl‐2 levels and increases of caspase‐3, caspase‐8, caspase‐9, and Bax, which revealed that α‐hederin induced apoptosis via triggering activation of the mitochondrial pathway. Furthermore, the above changes were amplified when pretreated with buthionine sulfoximine, whereas attenuated in the group pretreated with NAC than α‐hederin alone (p < .05). In addition, α‐hederin significantly inhibited the growth of xenografted gastric tumors with favorable safety. In conclusion, α‐hederin could inhibit the proliferation and induce apoptosis of gastric cancer accompanied by glutathione decrement and reactive oxygen species generation via activating mitochondrial dependent pathway.     

Cytotoxicity of Tanshinone IIA combined with Taxol on drug‐resist breast cancer cells MCF‐7 through inhibition of Tau

Drug resistance represents a major obstacle to improving the overall response and survival of cancer patients. Taxol is one of the most commonly used chemotherapy agents in breast cancer. As with many cancer therapeutic agents, resistance remains a significant problem when using Taxol to treat malignancies. In this study, estrogen receptor positive breast cancer cells MCF‐7 were induced Taxol resistance. And Tanshinone IIA combined with Taxol was chosen to treat it. The drugs combination showed additive effect in most drug concentrations. Drug resistance cancer cells showed a higher microtubule associated protein (Tau) expression, which was considered as one of the reasons for Taxol resistance. Tanshinone IIA inhibited the expression of Tau in MCF‐7 cells and resulted in higher sensibility of Taxol. Moreover, Tanshinone IIA also showed cytotoxicity to MCF‐7, which might be related to its estrogenicity effect. In conclusion, the combination of Tanshinone IIA and Taxol showed higher cytotoxicity to Taxol resistant MCF‐7 cells, which might be related to the inhibition of Tau.     

Anti‐Proliferative Effects of Polyphenols from Pomegranate Rind (Punica granatum L.) on EJ Bladder Cancer Cells Via Regulation of p53/miR‐34a Axis

miRNAs and their validated miRNA targets appear as novel effectors in biological activities of plant polyphenols; however, limited information is available on miR‐34a mediated cytotoxicity of pomegranate rind polyphenols in cancer cell lines. For this purpose, cell viability assay, Realtime quantitative PCR for mRNA quantification, western blot for essential protein expression, p53 silencing by shRNA and miR‐34a knockdown were performed in the present study. EJ cell treatment with 100 µg (GAE)/mL PRE for 48 h evoked poor cell viability and caspase‐dependent pro‐apoptosis appearance. PRE also elevated p53 protein and triggered miR‐34a expression. The c‐Myc and CD44 were confirmed as direct targets of miR‐34a in EJ cell apoptosis induced by PRE. Our results provide sufficient evidence that polyphenols in PRE can be potential molecular clusters to suppress bladder cancer cell EJ proliferation via p53/miR‐34a axis. Copyright © 2015 John Wiley & Sons, Ltd.     

Inhibitory effects of the aqueous extract of Magnolia officinalis on the responses of human urinary bladder cancer 5637 cells in vitro and mouse urinary bladder tumors induced by N‐Butyl‐N‐(4‐hydroxybutyl) nitrosamine in vivo

This study investigated the anticancer activity of Magnolia officinalis on urinary bladder cancer in vitro and in vivo, and elucidated the mechanism of its activity. An aqueous extract of M. officinalis inhibited cell viability and DNA synthesis in cultured human urinary bladder cancer 5637 cells. Inhibition of proliferation was the result of apoptotic induction, because FACS analyses of 5637 cells treated with M. officinalis showed a sub‐G1 phase accumulation. M. officinalis extract also increased cytoplasmic DNA–histone complex dose‐dependently. These inhibitory effects were associated with the upregulation of proapoptotic molecules Bax, cytochrome c and caspase 3. Treatment of 5637 cells with M. officinalis extract suppressed the expression of matrix metalloproteinase 2 (MMP‐2) and MMP‐9, as revealed by zymographic and immunoblot analyses. When M. officinalis extract was given to mice simultaneously with the carcinogen N‐butyl‐N‐(4‐hydroxybutyl) nitrosamine, which induces urinary bladder tumors, the size of the induced tumors was smaller. Finally, histological data indicated that the histological grade of carcinoma and the depth of invasion were dramatically decreased by treatment with M. officinalis extract in mice with N‐butyl‐N‐(4‐hydroxybutyl) nitrosamine‐induced urinary bladder tumors. In conclusion, the findings showed that M. officinalis extract exhibited potential chemopreventive activity against urinary bladder tumor in vitro and in vivo. Copyright © 2008 John Wiley & Sons, Ltd.     

Gleditsia sinensis thorn extract inhibits human colon cancer cells: the role of ERK1/2, G2/M‐phase cell cycle arrest and p53 expression

The thorns of Gleditsia sinensis are used as a medicinal herb in China and Korea. However, the mechanisms responsible for the antitumor effects of the water extract of Gleditsia sinensis thorns (WEGS) remain unknown. HCT116 cells treated with the WEGS at a dose of 800 μg/mL (IC₅₀) showed a significant decrease in cell growth and an increase in cell cycle arrest during the G2/M‐phase. G2/M‐phase arrest was correlated with increased p53 levels and down‐regulation of the check‐point proteins, cyclinB1, Cdc2 and Cdc25c. In addition, treatment with WEGS induced phosphorylation of extracellular signal‐regulated kinase (ERK), p38 MAP kinase and JNK (c‐Jun N‐terminal kinases). Moreover, inhibition of ERK by treatment of cells with the ERK‐specific inhibitor PD98059 blocked WEGS‐mediated p53 expression. Similarly, blockage of ERK function in the WEGS‐treated cells reversed cell‐growth inhibition and decreased cell cycle proteins. Finally, in vivo WEGS treatment significantly inhibited the growth of HCT116 tumor cell xenografts in nude mice with no negative side effects, including loss of body weight. These results describe the molecular mechanisms whereby the WEGS might inhibit proliferation of colon cancer both in vitro and in vivo, suggesting that WEGS has potential as an anticancer agent for the treatment of malignancies. Copyright © 2010 John Wiley & Sons, Ltd.     

[6]‐Gingerol enhances the cisplatin sensitivity of gastric cancer cells through inhibition of proliferation and invasion via PI3K/AKT signaling pathway

Cisplatin‐based chemotherapy is a widely used chemotherapeutic regimen for gastric cancer; however, drug resistance limits its efficacy. [6]‐Gingerol has been found to exhibit anticancer effects. Here, we aim to explore the potential of [6]‐gingerol in combination with cisplatin as a new regimen for gastric cancer. CCK‐8 assay and colony formation assay were used to determine the effect of [6]‐gingerol in combination with cisplatin on cell viability of gastric cancer cells. Flow cytometry was performed to assess cell cycle distribution. Wound‐healing assay and transwell invasion assay were conducted to examine the migration and invasion abilities. Cell cycle and invasion‐related proteins and mRNAs, as well as PI3K/AKT signaling proteins, were assessed by western blotting and quantitative real‐time polymerase chain reaction. Combination of [6]‐gingerol with cisplatin inhibited cell viability and enhanced cell cycle arrest at G1 phase compared with cisplatin alone. The combination treatment inhibited cell migration and invasion ability and decreased cyclin D1, cyclin A2, matrix metalloproteinase‐9, p‐PI3K, AKT, and p‐AKT protein expressions and increased P21 and P27 mRNA levels. Our study demonstrates that [6]‐gingerol enhances the cisplatin sensitivity of gastric cancer cells and that the mechanisms involve G1 phase arrest, migration and invasion suppression via PI3K/AKT signaling pathway.