Modulating Bcl-2 family proteins and caspase-3 in induction of apoptosis by paeoniflorin in human cervical cancer cells

Paeoniflorin (PF), the principal bioactive component in the paeony root, has been used alone or combined with other herbs for many years in traditional Chinese medicine. New studies have shown that PF possesses an antitumor effect. However, the effect of PF on human cervical cancer cells has not been reported previously. This study determined the effect of PF on human cervical cancer cell line (HeLa) cells by the methyl thiazolyl tetrazolium (MTT) assay, flow cytometry with annexin V‐fluorescein isothiocyanate (FITC)/propidium iodide (PI) technology, the transmission electron microscope (TEM) and immunocytochemical technique. After treatment with PF, the proliferation of HeLa cells was inhibited in a dose and time‐dependent manner (p < 0.05). The apoptosis rate of HeLa cells increased with ascending concentrations of PF (p < 0.05) and the proportion of HeLa cells in S phase showed an increasing trend also. Typical apoptotic changes of HeLa cells exposed to PF were seen under the TEM. Meanwhile, there was a decrease in the expression of Bcl‐2 and an enhancement in the expression of Bax and caspase‐3 genes compared with the control group (p < 0.05). In conclusion, PF can induce significantly the apoptosis of HeLa cells, which may be demonstrated by the down‐regulation of anti‐apoptosis gene Bcl‐2 and the up‐regulation of pro‐apoptosis genes Bax and caspase‐3. Copyright © 2011 John Wiley & Sons, Ltd.     

The Estrogenic Activity of Isoflavones Extracted from Chickpea Cicer arietinum L Sprouts in Vitro

Isoflavones have drawn attention due to their potential therapeutic use. Isoflavones are the important chemical components of the seeds and sprouts of chickpea and higher isoflavones in sprouts than in seeds. However, there have been no previous reports of the estrogenic activity of isoflavones extracted from chickpea Cicer arietinum L sprouts (ICS) in vitro. In this study, which incorporated several in vitro bioassays methods, we systematically evaluated the estrogenic properties of ICS. MTT assay showed that ICS at the low concentration ranges (10^?3–1 mg/L) promoted MCF‐7 cell growth, while at high concentrations, (>1 mg/L) inhibited cell proliferation, indicating ICS worked at a diphasic mechanism. Flow cytometric analysis further calculated the proliferation rate of ICS at low concentration (1 mg/L). ERα/Luc trans‐activation assay and then semi‐quantitative RT‐PCR analysis indicated that ICS at low concentrations induced ERα‐mediated luciferase activity in MCF‐7 cells and promoted the ER downstream target gene pS2 and PR trans‐activation. These effects were inhibited by ICI 182,780, a special antagonist of ER, indicating that an ER‐mediating pathway was involved. Alkaline phosphatase (AP) expression in Ishikawa cells showed that ICS at low concentrations stimulated AP expression. Our current study is the first to demonstrate that ICS has significant estrogenic activity in vitro. ICS may be useful as a supplement to hormone replacement therapy and in dietary supplements. Copyright © 2012 John Wiley & Sons, Ltd.     

Protocatechuic Aldehyde Inhibits Lipopolysaccharide‐induced Human Umbilical Vein Endothelial Cell Apoptosis via Regulation of Caspase‐3

Apoptosis of vascular endothelial cells results in the loss of endothelial integrity, and is a risk factor of atherosclerosis (AS). Lipopolysaccharide (LPS) stimulates inflammation during AS. The current study examined the effect of a potent water‐soluble antioxidant, protocatechuic aldehyde (PCA; derived from the Chinese herb Salvia miltiorrhiza) on apoptosis in human umbilical vein endothelial cells (HUVECs) stimulated with LPS. The LPS (15 µg/ml) stimulation for 30 h resulted in significant HUVEC apoptosis, as detected by Hoechst 33258 staining and Annexin V analysis. The PCA (0.25–1.0 mmol/L, 12 h) inhibited LPS‐induced HUVEC apoptosis in a dose‐dependent manner. Lipopolysaccharide induced caspase‐3 activation, but had no significant effect on caspase‐2, Bcl‐2/Bax, cytochrome c, caspase‐9 and granzyme B expression. Protocatechuic aldehyde (0.25–1.0 mmol/L) significantly inhibited caspase‐3 activation in a dose‐dependent manner. A specific caspase‐3 inhibitor also protected against LPS‐induced apoptosis; however, no cooperative effect of PCA and the inhibitor was observed in this study. Collectively, these results indicate that PCA inhibits LPS‐induced apoptosis in HUVECs through a mechanism that involves caspase‐3. Copyright © 2012 John Wiley & Sons, Ltd.     

Dihydroxy‐Isosteviol Methyl Ester from Pulsatilla nigricans Induces Apoptosis in HeLa Cells: Its Cytoxicity and Interaction with Calf Thymus DNA

Dihydroxy‐isosteviol methyl ester (DIME), the principal biological compound isolated from the medicinal plant Pulsatilla nigricans (Fam: Ranunculaceae) having the molecular formula of C₂₁H₃₄O₃ (molecular weight 334.25), was administered to cervical cancer cells (HeLa) in vitro to evaluate its possible apoptotic (anti‐cancer) potentials. We analyzed the expression of p53, Bax, Bcl2, Apaf and caspase 3 signal proteins and analyzed the early apoptotic events in HeLa cells induced by DIME using protocols like Annexin V‐FITC and PI staining. DIME caused a significant decrease in cell viability, induced nuclear condensation and inter‐nucleosomal DNA fragmentation. We further studied the interaction of DIME with calf thymus DNA as target through circular‐dichroism spectra. Results showed that DIME interacted with DNA, bringing indiscernible changes in structure and conformation. Thus, DIME showed its capability to induce apoptosis in cancer cells, signifying its utility in drug design as a possible candidate for chemoprevention. Copyright © 2012 John Wiley & Sons, Ltd.     

Morin enhances auranofin anticancer activity by up‐regulation of DR4 and DR5 and modulation of Bcl‐2 through reactive oxygen species generation in Hep3B human hepatocellular carcinoma cells

Evidence suggests that auranofin (AF) exhibits anticancer activity by inhibiting thioredoxin reductase (TrxR). Here, in this study, we have investigated the synergistic effects of AF and morin and their mechanism for the anticancer effects focusing on apoptosis in Hep3B human hepatocellular carcinoma cells. We assessed the anticancer activities by annexin V/PI double staining, caspase, and TrxR activity assay. Morin enhances the inhibitory effects on TrxR activity of AF as well as reducing cell viability. Annexin V/PI double staining revealed that morin/AF cotreatment induced apoptotic cell death. Morin enhances AF‐induced mitochondrial membrane potential (ΔΨm) loss and cytochrome c release. Further, morin/AF cotreatment upregulated death receptor DR4/DR5, modulated Bcl‐2 family members (upregulation of Bax and downregulation of Bcl‐2), and activated caspase‐3, ‐8, and ‐9. Morin also enhances AF‐induced reactive oxygen species (ROS) generation. The anticancer effects results from caspase‐dependent apoptosis, which was triggered via extrinsic pathway by upregulating TRAIL receptors (DR4/DR5) and enhanced via intrinsic pathway by modulating Bcl‐2 and inhibitor of apoptosis protein family members. These are related to ROS generation. In conclusion, this study provides evidence that morin can enhance the anticancer activity of AF in Hep3B human hepatocellular carcinoma cells, indicating that its combination could be an alternative treatment strategy for the hepatocellular carcinoma.     

7,3′‐dimethoxy hesperetin induces apoptosis of fibroblast‐like synoviocytes in rats with adjuvant arthritis through caspase 3 activation

Approaches inducing fibroblast‐like synoviocytes (FLS) apoptosis in rheumatoid arthritis (RA) patients have been considered as a promising strategy for treating RA. Here, adjuvant arthritis (AA) in rat was induced by complete Freund's adjuvant and FLS were separated and cultured using a tissue explant cultivation method. The apoptotic effect of 7,3′‐dimethoxy hesperetin (DMHP, a highly antirheumatic active derivative of hesperidin) on AA FLS was evaluated with MTT assay, Hoechst staining and flow cytometry analysis. Bcl‐2, Bax, caspase 3 gene expressions and caspase 3 activity were assayed to identify whether caspase 3 was involved in the apoptosis induced by DMHP. It was found that DMHP significantly decreased AA FLS proliferation in vitro by MTT assay. The AA FLS treated with DMHP displayed typical apoptotic characteristics including irregularity in shape, nuclear shrinkage and chromatin condensation. Flow cytometry analysis indicated that DMHP could obviously increase the AA FLS apoptosis rate. Compared with the AA‐FLS control group, DMHP markedly decreased the mRNA expression of Bcl‐2, whereas those of Bax and caspase 3 were increased. Moreover, DMHP significantly increased caspase 3 activity in a dose‐dependent manner. In aggregate, the results demonstrate that DMHP effectively induces AA FLS apoptosis through caspase 3 activation and can be considered as a possible antirheumatic agent. Copyright © 2010 John Wiley & Sons, Ltd.     

6‐Acetoxy Cyperene,a Patchoulane‐type Sesquiterpene Isolated from Cyperus rotundus Rhizomes Induces Caspase‐dependent Apoptosis in Human Ovarian Cancer Cells

Cyperus rotundus (Cyperaceae) has been widely used in traditional medicine for the treatment of various diseases, including cancer. Although an anti‐tumour effect has been suggested for C. rotundus, the anti‐tumour effects and underlying molecular mechanisms of its bioactive compounds are poorly understood. The n‐hexane fraction of an ethanol extract of C. rotundus rhizomes was found to inhibit cell growth in ovarian cancer (A2780, SKOV3 and OVCAR3) and endometrial cancer (Hec1A and Ishikawa) cells. Among the thirteen sesquiterpenes isolated from the n‐hexane fraction, some patchoulane‐type compounds, but not eudesmane‐type compounds, showed moderate cytotoxic activity in human ovarian cancer cells. In particular, the patchoulane sesquiterpene 6‐acetoxy cyperene had the most potent cytotoxicity. In this regard, propidium iodide/Annexin V staining and terminal deoxynucleotidyl transferase dUTP (deoxynucleotide triphosphate) nick end labeling assay were performed to study cell cycle progression and apoptosis. 6‐acetoxy cyperene induced apoptosis, as shown by the accumulation of sub‐G1 and apoptotic cells. Furthermore, treatment with 6‐acetoxy cyperene stimulated the activation of caspase‐3, caspase‐8 and caspase‐9 and poly(ADP‐ribose)polymerase in a dose‐dependent manner. Pretreatment with caspase inhibitors neutralized the pro‐apoptotic activity of 6‐acetoxy cyperene. Taken together, these data suggest that 6‐acetoxy cyperene, a patchoulane‐type sesquiterpene isolated from C. rotundus rhizomes, is an anti‐tumour compound that causes caspase‐dependent apoptosis in ovarian cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.     

Liquiritigenin induces mitochondria‐mediated apoptosis via cytochrome c release and caspases activation in heLa Cells

It has been demonstrated that many flavonoids possess a potent and broad spectrum of antitumor activity. Liquiritigenin is a flavanone extracted from Glycyrrhizae. This study investigated the effects of liquiritigenin on cell viability and apoptosis induction in human cervical carcinoma (HeLa) cells. The results show that liquiritigenin significantly suppressed cell proliferation in a dose‐ and time‐dependent manner in HeLa cells. In addition, liquiritigenin promoted apoptosis in HeLa cells, evidenced by apoptotic morphological changes and Annexin‐V binding. The apoptosis induction with liquiritigenin is associated with the up‐regulation of p53 and Bax, along with down‐regulation of Bcl‐2 and survivin. Finally, examination of the mitochondrial pathway of apoptosis revealed that cytochrome c is released from mitochondria to cytosol, associated with the activation of caspase‐9 and ‐3, and the cleavage of poly (ADP‐ribose) polymerase (PARP). Overall, the results indicate that liquiritigenin induces apoptosis in part via the mitochondrial pathway, which is associated with p53 up‐regulation, release of cytochrome c and elevated activity of caspase‐9 and ‐3 in HeLa cells. Copyright © 2010 John Wiley & Sons, Ltd.     

Phloroglucinol Protects INS‐1 Pancreatic β‐cells Against Glucotoxicity‐Induced Apoptosis

Decreasing numbers, and impaired function, of pancreatic β‐cells are key factors in the development of type 2 diabetes. This study was designed to investigate whether phloroglucinol protected pancreatic β‐cells against glucotoxicity‐induced apoptosis using a rat insulinoma cell line (INS‐1). High glucose treatment (30 mM) induced INS‐1 cell death; however, the level of glucose‐induced apoptosis was significantly reduced in cells treated with 100‐μM phloroglucinol. Treatment with 10–100‐μM phloroglucinol increased cell viability and decreased intracellular levels of reactive oxygen species, nitric oxide, and lipid peroxidation dose‐dependently in INS‐1 cells pretreated with high glucose. Furthermore, phloroglucinol treatment markedly reduced the protein expression of Bax, cytochrome c, and caspase 9, while increasing anti‐apoptotic Bcl‐2 protein expression. Cell death type was examined using annexin V/propidium iodide staining, revealing that phloroglucinol markedly reduced high glucose‐induced apoptosis. These results demonstrated that phloroglucinol could be useful as a potential therapeutic agent for the protection of pancreatic β‐cells against glucose‐induced apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.     

6‐Gingerol Mediates its Anti Tumor Activities in Human Oral and Cervical Cancer Cell Lines through Apoptosis and Cell Cycle Arrest

6‐Gingerol, a potent nutraceutical, has been shown to have antitumor activity in different tumors, although its mechanism of action is not well understood. In this study, we evaluated antitumor activities of 6‐gingerol on human oral (SCC4, KB) and cervical cancer (HeLa) cell lines with or without wortmannin, rapamycin, and cisplatin. Tumor cell proliferation was observed using 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H tetrazolium, inner salt assay, cell cycle analysis by propidium iodide labeling and flow cytometry, apoptosis by Annexin‐V binding assay, and caspase activity by chemiluminescence assay. 6‐Gingerol showed dose‐dependent cytotoxicity in all three cell lines. Combinations of 6‐gingerol with wortmannin and cisplatin showed additive effects, while with rapamycin, it showed 50% cytotoxicity that was equivalent to IC₅₀ of 6‐gingerol alone. Treatment with 6‐gingerol resulted in G2‐phase arrest in KB and HeLa cells and S‐phase arrest in SCC4 cells. 6‐Gingerol, wortmannin, and rapamycin treatment showed almost two‐fold higher expression of caspase 3 in all cell lines. The results imply that 6‐gingerol either alone or in combination with PI‐3 K inhibitor and cisplatin may provide better therapeutic effects in oral and cervical carcinoma. Thus, 6‐gingerol appears to be a safe and potent chemotherapeutic/chemopreventive compound acting through cell cycle arrest and induction of apoptosis in human oral and cervical tumor cells. Copyright © 2016 John Wiley & Sons, Ltd.     

Pachymic Acid Induces Apoptosis of EJ Bladder Cancer Cells by DR5 Up‐Regulation,ROS Generation,Modulation of Bcl‐2 and IAP Family Members

Pachymic acid (PA) is a lanostane‐type triterpenoid derived from Poria cocos mushroom that possess various biological effects such as anti‐cancer, antiinflammatory and anti‐metastasis effects. In this study, we investigated the anti‐cancer effects of PA in EJ bladder cancer cells. The results showed that PA significantly inhibited proliferation of EJ cells in a dose‐dependent manner. PA induced accumulation of sub‐G1 DNA content (apoptotic cell population), apoptotic bodies and chromatin condensation and DNA fragmentation in EJ cells in a dose‐dependent manner. PA also induces activation of caspase‐3, ‐8 and ‐9, and subsequent cleavage of poly (ADP‐ribose) polymerase, and significantly suppressed the inhibitor of apoptosis protein family proteins in a dose‐dependent manner. Furthermore, PA activates Bid and induced the loss of mitochondrial membrane potential (ΔΨ_m) with up‐regulated pro‐apoptotic proteins (Bax and Bad), down‐regulated anti‐apoptotic proteins (Bcl‐2 and Bcl‐xL) and cytochrome c release. In turn, PA increased the generation of reactive oxygen species (ROS); also, the ROS production was blocked by N‐acetyl‐L‐cysteine. The expressions of TNF‐related apoptosis inducing ligand and death receptor 5 were up‐regulated by PA in a dose‐dependent manner, suggesting extrinsic pathway also involved in PA‐induced apoptosis. This study provides evidence that PA might be useful in the treatment of human bladder cancer. Copyright © 2015 John Wiley & Sons, Ltd.     

Ramalin‐Mediated Apoptosis Is Enhanced by Autophagy Inhibition in Human Breast Cancer Cells

Breast cancer, the most commonly diagnosed cancer in women worldwide, is treated in various ways. Ramalin is a chemical compound derived from the Antarctic lichen Ramalina terebrata and is known to exhibit antioxidant and antiinflammatory activities. However, its effect on breast cancer cells remains unknown. We examined the ability of ramalin to induce apoptosis and its mechanisms in MCF‐7 and MDA‐MB‐231 human breast cancer cell lines. Ramalin inhibited cell growth and induced apoptosis in both cell lines in a concentration‐dependent manner. By upregulating Bax and downregulating Bcl‐2, ramalin caused cytochrome c and apoptosis‐inducing factor to be released from the mitochondria into the cytosol, thus activating the mitochondrial apoptotic pathway. In addition, activated caspase‐8 and caspase‐9 were detected in both types of cells exposed to ramalin, whereas ramalin activated caspase‐3 only in the MDA‐MB‐231 cells. Ramalin treatment also increased the levels of LC3‐II and p62. Moreover, the inhibition of autophagy by 3‐methyladenine or Atg5 siRNA significantly enhanced ramalin‐induced apoptosis, which was accompanied by a decrease in Bcl‐2 levels and an increase in Bax levels. Therefore, autophagy appears to be activated as a protective mechanism against apoptosis in cancer cells exposed to ramalin. These findings suggest that ramalin is a potential anticancer agent for the treatment of patients with non‐invasive or invasive breast cancer. Copyright © 2015 John Wiley & Sons, Ltd.     

Curcumin Inhibits Proliferation and Induces Apoptosis of Human Colorectal Cancer Cells by Activating the Mitochondria Apoptotic Pathway

Curcumin, a natural plant extract from Curcuma longa, is known for its anti‐carcinogenic and chemopreventive effects on a variety of experimental cancer models. In this study, we evaluated the effects of curcumin and elucidated its mechanism in human colorectal carcinoma cells. Cell viability assay showed that curcumin significantly inhibited the growth of LoVo cells. Curcumin treatment induced the apoptosis accompanied by ultra‐structural changes and release of lactate dehydrogenase in a dose‐dependent manner. Moreover, treatment with 0–30 µg/mL curcumin decreased the mitochondrial membrane potential and activated the caspase‐3 and caspase‐9 in a dose‐ and time‐dependent manner. Nuclear and annexin V/PI staining showed that curcumin induced the apoptosis of LoVo cells. FACS analysis revealed that curcumin could induce the cell cycle arrest of LoVo cells at the S phase. Furthermore, western blotting analysis indicated that curcumin induced the release of cytochrome c, a significant increase of Bax and p53 and a marked reduction of Bcl‐2 and survivin in LoVo cells. Taken together, our results suggested that curcumin inhibited the growth of LoVo cells by inducing apoptosis through a mitochondria‐mediated pathway. Copyright © 2012 John Wiley & Sons, Ltd.     

Apoptotic Effect of Sanggenol L via Caspase Activation and Inhibition of NF‐κB Signaling in Ovarian Cancer Cells

In the present study, the underlying apoptotic mechanism of sanggenol L was elucidated in ovarian cancer cells. Sanggenol L showed cytotoxic and antiproliferative effect in A2780, SKOV‐3, and OVCAR‐3 ovarian cancer cells in a concentration‐dependent fashion. Consistently, sanggenol L increased sub‐G1 phase population and early and late apoptotic portion in ovarian cancer cells. Also, sanggenol L activated caspase9/3, suppressed the phosphorylation of IκBα and p65 NF‐κB (nuclear factor kappa‐light‐chain‐enhancer of activated B cells), attenuated the expression of Cyclin D1, and cleaved poly(adenosine diphosphate ribose ‐ribose) polymerase in SKOV‐3, A2780, and OVCAR‐3 cells. Furthermore, sanggenol L blocked nuclear translocation of NF‐κB and also attenuated the expression of NF‐κB related genes such as c‐Myc, Cyclin D1, and Bcl‐_XL, Bcl‐2, in lipopolysaccharide‐treated SKOV‐3 cells. Overall, our findings for the first time suggest that sanggenol L induces apoptosis via caspase activation and inhibition of NF‐κB/IκBα phosphorylation as a potent chemotherapeutic agent for ovarian cancers. Copyright © 2015 John Wiley & Sons, Ltd.     

Apoptosis of BGC823 cell line induced by p‐hydroxymethoxybenzobijuglone,a novel compound from Juglans mandshurica

p‐Hydroxymethoxybenzobijuglone (HMBBJ), a new quinone compound isolated from Juglans mandshurica (by bioassay‐guided fractionation), showed cytotoxic activity in the gastric carcinoma cell line BGC823. The growth of BGC823 cells was inhibited as demonstrated by MTT assay and several cellular characteristic changes, such as cell shrinkage, chromatin condensation and apoptotic body formation with programmed cell death. Flow cytometry analysis revealed that the BGC823 cell cycle was arrested at G2/M phase by HMBBJ, and the apoptotic rate of BGC823 cells increased with respect to HMBBJ in a dose‐dependent manner. HMBBJ also activated caspase‐3, decreased the expression of Bcl‐2 and caused a decrease in the mitochondrial membrane potential (ΔΨ_m). These findings suggest that HMBBJ could significantly induce apoptosis in BGC823 cells and should be considered as a potential candidate for a chemotherapeutic drug against cancer. Copyright © 2008 John Wiley & Sons, Ltd.     

Emodin Regulates Apoptotic Pathway in Human Liver Cancer Cells

Emodin, a natural anthraquinone, has been reported to possess antiproliferative effects in many cancer cell lines. However, anticancer mechanism against human liver cancer remains unclear. In this study, we observed that emodin induced apoptosis in HepG2 cells and caused a significant accumulation of cells in the G1 phase. Western blot data showed that emodin treatment caused the increasing of release of cytochrome c into cytosol from mitochondria and the activation of caspase‐8 and caspase‐9, which suggest that the intrinsic and extrinsic pathways could be involved. Emodin treatment also resulted in a dose‐dependent accumulation of intracellular reactive oxygen species. Furthermore, emodin increased the protein level of p53 and decreased the protein level of NF‐κB/p65 in HepG2 cells, which indicated these two regulators might play a role in emodin‐induced apoptosis. Computational modeling showed that emodin could directly bind to the BH3 domain of Bcl‐2 through forming one hydrogen bond with Ala146 residue in Bcl‐2. From these examinations, emodin not only significantly downregulated expression of Bcl‐2 but also inhibited the heterodimerization of Bcl‐2 with Bax because of strong interaction between emodin and Bcl‐2. These suggest that emodin induces apoptosis in liver cancer cell line through a multifaceted complex cascade of events. Copyright © 2012 John Wiley & Sons, Ltd.     

Corosolic Acid Triggers Mitochondria and Caspase‐dependent Apoptotic Cell Death in Osteosarcoma MG‐63 Cells

The response of osteosarcoma MG‐63 cells to corosolic acid treatment has been investigated. The results showed that corosolic acid significantly inhibited cell viability in both a dose and a time dependent manner. It was found that corosolic acid increased the Bax/Bcl‐2 ratio by up‐regulating Bax expression, disrupted mitochondrial membrane potential and triggered the release of cytochrome c from mitochondria into the cytoplasm. Corosolic acid treatment triggered the activation of caspase‐8, 9 and 3. The apoptosis was obviously inhibited by pretreatment with a general caspase inhibitor, z‐VAD‐FMK. Moreover, pretreatment of CsA, a cyclophilin D ligand that inhibits mitochondria potential uncoupling, prevented the activation of caspase‐9 and caspase‐3, but not caspase‐8, and the apoptosis of MG‐63 cells, triggered by corosolic acid. All these results indicated that corosolic acid‐induced apoptosis was associated with the activation of caspases via a mitochondrial pathway. Copyright © 2011 John Wiley & Sons, Ltd.     

Brassinin Induces Apoptosis in PC‐3 Human Prostate Cancer Cells through the Suppression of PI3K/Akt/mTOR/S6K1 Signaling Cascades

The oncogenic PI3K/Akt/mammalian target of rapamycin (mTOR) signaling axis and its downstream effector, the ribosomal protein S6 kinase 1 (S6K1) play a key role in mediating cell survival in various tumor cells. Here, we investigated the effects of brassinin (BSN), a phytoalexin first identified as a constituent of cabbage, on the PI3K/Akt/mTOR/S6K1 activation, cellular proliferation, and apoptosis in PC‐3 human prostate cancer. BSN exerted a significant dose‐dependent cytotoxicity and reduced constitutive phosphorylation of Akt against androgen‐independent PC‐3 cells as compared to androgen‐dependent LNCaP cells. Moreover, knockdown of androgen receptor (AR) by small interfering RNA enhanced the potential effect of BSN on induction of apoptosis in LNCaP cells. BSN clearly suppressed the constitutive activation of PI3K/Akt/mTOR/S6K1 signaling cascade, which correlated with the induction of apoptosis as characterized by accumulation of cells in subG1 phase, positive Annexin V binding, TUNEL staining, loss of mitochondrial membrane potential, down‐regulation of antiapoptotic and proliferative proteins, activation of caspase‐3, and cleavage of PARP. Additionally, BSN could block broad‐spectrum inhibition of PI3K/Akt/mTOR/S6K1 axes, and aberrant Akt activation by pcDNA3‐myr‐HA‐Akt1 plasmid could not prevent the observed suppressive effect of BSN on constitutive mTOR activation. Finally, overexpression of Bcl‐2 also attenuated BSN‐mediated apoptosis in PC‐3 cells. Taken together, our findings suggest that BSN can interfere with multiple signaling cascades involved in tumorigenesis and might be provided as a potential therapeutic candidate for both the prevention and treatment of prostate cancer. Copyright © 2013 John Wiley & Sons, Ltd.     

Inhibitory Effects of Nobiletin on Hepatocellular Carcinoma In Vitro and In Vivo

Nobiletin (5, 6, 7, 8, 3′ 4′‐hexamethoxyflavone) is a major anticancer component in juice from zhishi (Rutaceae). This study aimed to investigate the inhibitory effect of Nobiletin on hepatic cancer cells both in vitro and in vivo. The 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide (MTT), growth curve, and clonogenic assay showed that nobiletin inhibited the proliferation of SMMC‐7721 cells in vitro. Hoechst staining observed the characteristics of cell apoptosis in nobiletin‐treated cells, and the apoptotic rates of treated groups were increased in a dose‐dependent manner. Flow cytometric analysis demonstrated that nobiletin could block the cell cycle arrested at G2 phase. Cell cycle analysis was performed using flow cytometry. Results showed that cell cycle phase distribution analysis showed G2 arrest. It was found that nobiletin downregulated the expressions of Bcl‐2 and COX‐2 and up‐regulated the expressions of Bax and caspase‐3 in SMMC‐7721 cells by western blotting. The experiment in vivo demonstrated that nobiletin significantly inhibited the growth of H22 transplantable tumor, downregulated the expressions of COX‐2, up‐regulated the expressions of Bax and caspase‐3 detected by immunohistochemistry and western blotting, and the ratios of Bcl‐2/Bax were decreased. Our results suggest that nobiletin has significant inhibitory effects on hepatocellular carcinoma both in vitro and in vivo. Copyright © 2013 John Wiley & Sons, Ltd.     

Bacopa monniera extract Induces apoptosis in murine sarcoma cells (S‐180)

The Ayurvedic system of medicine recommends Bacopa monniera (BM) in the treatment of tumors. The present study aims to determine the mode of cell death induced by the ethanolic extract of BM in mouse S‐180 cells. BM‐treated S‐180 cells were assessed for cell viability in a dose‐ and time‐dependent manner using dye exclusion studies. Morphological changes in the BM‐treated and untreated cells were studied by transmission electron microscopy (TEM). Glutathione (GSH) levels were quantified and the percentage of apoptotic cells was determined using Annexin V‐FITC assay. The results indicate that BM induces a dose‐ and time‐dependent loss of cell viability with maximum cytotoxicity at 48 h at a concentration of 550 µg/ml. TEM studies indicate apoptosis in the BM‐treated cells. GSH levels were decreased in the BM‐treated cells and Annexin V‐FITC assay revealed 90.2% of the cells as apoptotic. Conclusively, BM induces cell death by apoptosis in S‐180 cells. Copyright © 2008 John Wiley & Sons, Ltd.