Improving anticancer activities of Oplopanax horridus root bark extract by removing water‐soluble components

O. horridus is used as a folk medicine by natives in the Northern Pacific coast of North America. This experiment studied the antiproliferative effects of the extract of O. horridus root bark and its fractions chromatographed from Dianion HP20 resin column with water, 30, 50, 70 and 100% ethanol on human breast cancer MCF‐7 cells and non‐small cell lung cancer (NSCLC) cells. The role of O. horridus in the cell cycle and apoptosis of MCF‐7 cells was also investigated. The results showed that the 70% and 100% ethanol fractions demonstrated more potent antiproliferative effects than the total extract on both cell lines. The antiproliferative effects may result from the enrichment of active constituents detected by high performance liquid chromatography (HPLC). The IC₅₀ of the total extract, 50, 70, and 100% ethanol fractions for antiproliferation on MCF‐7 cells were 248.4, 123.1, 44.0, and 31.5 μg/mL, respectively, and on NSCLC cells were 125.3, 271.1, 17.6, and 23.2 μg/mL, respectively. On the other hand, the water and 30% ethanol fractions significantly promoted cell proliferation on MCF‐7 cells at concentrations > 100 μg/mL, suggesting that the hydrophilic fractions should be removed from the extract when used for cancer chemoprevention in order to achieve desirable activities. The effects of the total extract on cell cycle and apoptosis were similar to that of the 100% ethanol fraction because of the similarity of their chemical composition. At higher concentrations, the apoptotic effects of the 70% ethanol fraction are more significant. Data from this study suggested that the 70% and 100% ethanol fractions are active antiproliferative fractions and that induction of apoptosis is the mechanism involved in the antiproliferative effect observed. Copyright © 2010 John Wiley & Sons, Ltd.     

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.     

Selective Inhibition of Cell Proliferation by Lycopene in MCF‐7 Breast Cancer Cells In vitro: A Proteomic Analysis

Lycopene, a red pigmented carotenoid present in many fruits and vegetables such as tomatoes, has been associated with the reduced risk of breast cancer. This study sought to identify proteins modulated by lycopene during cell proliferation of the breast cancer cell line MCF‐7 to gain an understanding into its mechanism of action. MCF‐7 breast cancer cells and MCF‐10 normal breast cells were treated with 0, 2, 4, 6, 8, and 10 μM of lycopene for 72 h. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) tetrazolium reduction assay was used to measure cell proliferation and two‐dimensional fluorescence difference gel electrophoresis to assess the changes in protein expression, which were identified using MALDI‐ToF/ToF (matrix‐assisted laser desorption ionization tandem time‐of‐flight) and Mascot database search. MTT and cell proliferation assays showed that lycopene selectively inhibited the growth of MCF‐7 but not MCF‐10 cells. Difference gel electrophoresis analysis revealed that proteins in the MCF‐7 cells respond differently to lycopene compared with the MCF‐10 cells. Lycopene altered the expression levels of proteins such as Cytokeratin 8/18 (CK8/18), CK19 and their post translational status. We have shown that lycopene inhibits cell proliferation in MCF‐7 human breast cancer cells but not in the MCF‐10 mammary epithelial cells. Lycopene was shown to modulate cell cycle proteins such as beta tubulin, CK8/18, CK19 and heat shock proteins. Copyright © 2012 John Wiley & Sons, Ltd.     

Curcumin Modulates miR‐19/PTEN/AKT/p53 Axis to Suppress Bisphenol A‐induced MCF‐7 Breast Cancer Cell Proliferation

Breast cancer is the most common cancer in women. Bisphenol A (BPA), as a known endocrine disrupter, is closely related to the development of breast cancer. Curcumin has been clinically used in chemopreventation and treatment of cancer; however, it remains unknown whether microRNAs are involved in curcumin‐mediated protection from BPA‐associated promotive effects on breast cancer. In the present study, we showed that BPA exhibited estrogenic activity by increasing the proliferation of estrogen‐receptor‐positive MCF‐7 human breast cancer cells and triggering transition of the cells from G1 to S phase. Curcumin inhibited the proliferative effects of BPA on MCF‐7 cells. Meanwhile, BPA‐induced upregulation of oncogenic miR‐19a and miR‐19b, and the dysregulated expression of miR‐19‐related downstream proteins, including PTEN, p‐AKT, p‐MDM2, p53, and proliferating cell nuclear antigen, were reversed by curcumin. Furthermore, the important role of miR‐19 in BPA‐mediated MCF‐7 cell proliferation was also illustrated. These results suggest for the first time that curcumin modulates miR‐19/PTEN/AKT/p53 axis to exhibit its protective effects against BPA‐associated breast cancer promotion. Findings from this study could provide new insights into the molecular mechanisms by which BPA exerts its breast‐cancer‐promoting effect as well as its target intervention. Copyright © 2014 John Wiley & Sons, Ltd.     

Cytotoxic Impact of Costunolide Isolated from Costus speciosus on Breast Cancer via Differential Regulation of Cell Cycle—An In‐vitro and In‐silico Approach

Costunolide, a sesquiterpene lactone, is a biologically active molecule found in most of the medicinally valuable plants. The present study aims to evaluate the anticancer property of costunolide isolated from Costus speciosus against breast cancer cell lines (MCF‐7 and MDA‐MB‐231). Costunolide effectively reduced the viability of both MCF‐7 and MDA‐MB‐231 cell lines at an IC₅₀ value of 40 μM. Flow cytometric analysis revealed costunolide mediated cell cycle arrest at G2/M phase in both the cell types. Western blotting results confirmed the alterations in the expression of cell cycle regulators (cyclin D1, D3, CDK‐4, CDK‐6, p18 INK4c, p21 CIP1/Waf‐1 and p27 KIP1) and apoptosis inducers (caspase‐3 and caspase‐9) upon costunolide treatment in comparison with their expressions in normal breast cell line (MCF‐10A). Costunolide mediated downregulation of positive cell cycle regulators and upregulation of negative cell cycle regulators were related to the induction of apoptosis in cancer cells. The above results were validated with in‐silico results that predicted stable interactions between costunolide and cancer targets. Thus costunolide effectively induced breast cancer cell apoptosis targeting cell cycle regulation, and the compound can be used as an effective herbal therapeutic molecule to treat breast cancer with further explorations. Copyright © 2015 John Wiley & Sons, Ltd.     

Cycloartane triterpenoids from Cimicifuga yunnanensis induce apoptosis of breast cancer cells (MCF7) via p53‐dependent mitochondrial signaling pathway

The present study was carried out to investigate the antitumor activity of five cycloartane triterpenoids isolated from Cimicifuga yunnanensis on the breast cancer cell line MCF7 and its corresponding drug resistant subline R‐MCF7, including cimigenol‐3‐O‐β‐d ‐xylopyranoside (compound 1), 25‐O‐acetylcimigenol‐3‐O‐β‐d ‐xylopyranoside (compound 2), 25‐chlorodeoxycimigenol‐3‐O‐β‐d ‐xylopyranoside (compound 3), 25‐O‐acetylcimigenol‐3‐O‐α‐l ‐arabinopyranoside (compound 4) and 23‐O‐acetylcimigenol‐3‐O‐β‐d ‐xylopyranoside (compound 5). The results showed that compounds 2–5 have relatively high antitumor activity on both MCF7 and R‐MCF7 cells. The involvement of apoptosis as a major cause of cycloartane triterpenoids‐induced cell death was further confirmed. The results of RT‐PCR showed that compounds 2–5 increased the expression of p53 and bax, which led to the loss of mitochondrial potential and then resulted in the activation of caspase‐7. These findings collectively demonstrated that compounds 2–5 induced apoptosis of MCF7 via p53‐dependent mitochondrial pathway. Copyright © 2010 John Wiley & Sons, Ltd.     

Bioactivity‐guided Isolation of Cytotoxic Sesquiterpene Lactones of Gochnatia polymorpha ssp. floccosa

Phytochemical study of Gochnatia polymorpha (Less) Cabr. ssp. floccosa Cabr. trunk bark, guided by antiproliferative assays on 10 human cancer cell lines and the VERO cell line, yielded six known compounds identified as the triterpene bauerenyl acetate, the guaianolide 11α,13‐dihydrozaluzanin C and the dimeric guaianolides 10‐desoxygochnatiolide A, gochnatiolide A, 8‐hydroxi‐10‐desoxygochnatiolide A and 8‐hydroxigochnatiolide A. Extracts, fractions of extracts and isolated compounds were tested in vitro against a panel of human cancer cell lines, including U251 (glioma, CNS), UACC‐62 (melanoma), MCF‐7 (breast), NCI‐ADR/RES (drug‐resistant ovarian), 786.0 (kidney), NCI‐H460 (lung, no small cells), PC‐3 (prostate), OVCAR‐3 (ovarian), HT‐29 (colon), K562 (leukemia) and against the VERO no cancer cell line. Bauerenyl acetate was inactive, while 11α,13‐dihydrozaluzanin C showed weak activity against UACC62 and the VERO cell line. The most active compounds were 10‐desoxygochnatiolide A and gochnatiolide A, which inhibited the growth of kidney, melanoma, ovarian‐resistant and glioma cell lines with values of TGI (total growth inhibition) varying 0.21–1.09 µg/mL. This is the first report about cytotoxic activity of dimeric lactones against cell lines. Copyright © 2011 John Wiley & Sons, Ltd.     

Quercetin reversed MDR in breast cancer cells through down‐regulating P‐gp expression and eliminating cancer stem cells mediated by YB‐1 nuclear translocation

Overexpression of P‐glycoprotein (P‐gp) plays an important role in mediating multidrug resistance (MDR), resulting in chemotherapy failure of tumor patients and enhancement of cancer stem cell characteristics. By preparing doxorubicin (Dox) resistant human breast cancer MCF‐7 cells, here, we wanted to evaluate the effects of quercetin (Que) on MDR reversal activity and investigate its possible mechanism. MCF‐7 and MCF‐7/dox cells were respectively treated by Dox, paclitaxel (Pac), or vincristine (Vcr) with or without Que intervention for 24 hr. Cell viability, cell apoptosis, cell cycle, intracellular drug accumulation, the expression of P‐gp and Y‐box binding protein 1 (YB‐1), and breast cancer stem cells (BCSCs) were then assessed. The results showed that Que significantly enhanced the antitumor activities of Dox, Pac, and Vcr in breast cancer cells. In addition, combined treatment of Dox, Pac, or Vcr with Que significantly downregulated P‐gp expression and eliminated BCSCs. Furthermore, combined treatment of Dox, Pac, or Vcr with Que significantly inhibited nuclear translocation of YB‐1. Thus, we speculated that Que reversed MDR in breast cancer cells through downregulating P‐gp expression and eliminating cancer stem cells mediated by YB‐1 nuclear translocation.     

Zanthoxylum usambarense (Engl.) Kokwaro (Rutaceae) Extracts Inhibit the Growth of the Breast Cancer Cell Lines MDA‐MB‐231 and MCF‐7, But Not the Brain Tumour Cell Line U251 In Vitro

Zanthoxylum usambarense (Engl.) Kokwaro has traditionally been used for the treatment of malaria, upper respiratory tract infections, cough, rheumatism, tooth decay and sore gums in Kenya and other African countries. Dried ground parts of Z. usambarense were extracted by maceration using methanol (MeOH) at room temperature, extract was dried and reconstituted in 70% aq. MeOH and partitioned against n‐hexane and chloroform (CHCl₃) to obtain MeOH, n‐hexane and CHCl₃ extracts. All extracts were assessed for cytotoxicity against two breast cancer cell lines, MDA‐MB‐231 and MCF‐7, and the brain tumour cell line U251 by the MTT assay. The free‐radical scavenging activity of the extracts was also determined by the 2,2‐diphenyl‐1‐picryhydrazyl (DPPH) assay. In the DPPH assay, the MeOH extract was found to be the most active free‐radical scavenger with a RC₅₀ value of 41.1 × 10^?3 mg/mL. It also displayed significant cytotoxicity against the MCF‐7 cell line (IC₅₀ 42.9 µg/mL) and appeared to have induced cell death through apoptosis. None of the test extracts showed any activity against the U251 cell line at test concentrations. The present findings demonstrated that Z. usambarense could be a potential source for new cytotoxic compounds for possible anticancer drug development. Copyright © 2012 John Wiley & Sons, Ltd.     

In Vitro and In Silico Evaluation of NF‐κB Targeted Costunolide Action on Estrogen Receptor‐Negative Breast Cancer Cells—A Comparison with Normal Breast Cells

Costunolide, a sesquiterpene lactone is a plant‐derived secondary metabolite found to be present in most of the pharmacologically active herbs, being the cause for their medicinal values. The present study aims to evaluate the cytotoxic effect of costunolide isolated from Costus speciosus rhizome extract on MDA‐MB‐231 cells and explore its targeted action in comparison with its action on the normal breast cells (MCF 10A). The effect of costunolide on cell viability of the cells was assessed by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide viability assay. The targeted action of the compound was analyzed comparing the effectiveness of the compound to alter the protein expression levels of NF‐κB subunits in the normal and the cancer cells using western blotting analysis. In silico studies were performed to predict the targeted interaction of costunolide with the NF‐κB subunit proteins. Costunolide inhibited the cell viability of MDA‐MB‐231 cells in a dose‐dependent manner leaving no significant change in the viability of the normal breast cells. The over expressed NF‐κB subunits – p65, 52 and 100 in the cancer cells were found to be downregulated when treated with costunolide at an effective dose of 20 and 40 μM costunolide. In silico results provided stable interactions between costunolide and the target proteins, supporting the in vitro results in addition. Thus, costunolide derived from C. speciosus plant source elevates a fresh conviction for its use in breast cancer therapy for its cytotoxic efficacy and non‐toxic nature. Copyright © 2014 John Wiley & Sons, Ltd.     

Anticancer activity and molecular mechanisms of α‐conidendrin,a polyphenolic compound present in Taxus yunnanensis,on human breast cancer cell lines

α‐Conidendrin is a polyphenolic compound found mainly in Taxus yunnanensis, as the source of chemotherapy drug paclitaxel, which has been used in traditional medicine for treatment of cancer. This study aimed to investigate the anticancer activity and molecular mechanisms of α‐conidendrin on breast cancer cell lines. The results of the present study show that α‐conidendrin possesses potent antiproliferative effects on breast cancer cell lines MCF‐7 and MDA‐MB‐231. α‐Conidendrin significantly induced apoptosis in breast cancer cells via reactive oxygen species generation, upregulation of p53 and Bax, downregulation of Bcl‐2, depolarization of mitochondrial membrane potential (MMP), release of cytochrome c from mitochondria, and activation of caspases‐3 and ‐9. α‐Conidendrin remarkably inhibited the proliferation of breast cancer cells through induction of cell cycle arrest by upregulating p53 and p21 and downregulating cyclin D1 and CDK4. Unlike breast cancer cells, the antiproliferative effect of α‐conidendrin on human foreskin fibroblast cells (normal cells) was very small. In normal cells, reactive oxygen species levels, loss of MMP, release of cytochrome c, mRNA expression of p53, p21, cyclin D1, CDK4, Bax, and Bcl‐2 as well as mRNA expression and activity of caspases‐3 and ‐9 were significantly less affected by α‐conidendrin compared with cancer cells. These results suggest that α‐conidendrin can be a promising agent for treatment of breast cancer with little or no toxicity against normal cells.     

Antiproliferative effect of benzophenones and their influence on cathepsin activity

The antiproliferative activity of two prenylated benzophenones isolated from Rheedia brasiliensis, the triprenylated garciniaphenone and the tetraprenylated benzophenone 7‐epiclusianone, was investigated against human cancer cell lines. The antiproliferative activity on melanoma (UACC‐62), breast (MCF‐7), drug‐resistant breast (NCI‐ADR), lung/non‐small cells (NCI460), ovarian (OVCAR 03), prostate (PC03), kidney (786‐0), lung (NCI‐460) and tongue (CRL‐1624 and CRL‐1623) cancer cells was determined using spectrophotometric quantification of the cellular protein content. The effect of these benzophenones on the activity of cathepsins B and G was also investigated. Garciniaphenone displayed cytostatic activity in all cell lines, whereas 7‐epiclusianone showed a dose‐dependent cytotoxic effect. The IC₅₀ values for cell proliferation revealed that 7‐epiclusianone is more active than garciniaphenone against most of the cell lines. Furthermore, the antiproliferative effects demonstrated by garciniaphenone and 7‐epiclusianone were related to their cathepsin inhibiting properties. In conclusion, 7‐epiclusianone is a promising naturally occurring agent which displays multiple inhibitory effects which may be working in concert to inhibit cancer cell proliferation in vitro. The putative pathway by which 7‐epiclusianone affects cancer cell development may involve cathepsin inhibition. Copyright © 2009 John Wiley & Sons, Ltd.     

Cytotoxic activity of carotenoid rich fractions from Haematococcus pluvialis and Dunaliella salina microalgae and the identification of the phytoconstituents using LC‐DAD/ESI‐MS

Microalgae represent a rich source that satisfies the growing need for novel ingredients of nutriceuticals, pharmaceuticals, and food supplements. Haematococcus pluvialis and Dunaliella salina microalgae are isolated from the Egyptian hydro‐flora and are reported for their potent antioxidant activities. The cytotoxic activity of different fractions of both microalgae was investigated on 4 cell lines HePG2, MCF7, HCT116, and A549. The carotenoid rich fraction of H. pluvialis showed potent cytotoxic activity against colon cancer cell line and moderate activity against both liver and breast cancer cell lines. On the other hand, the carotenoid rich fraction of D. salina showed mild cytotoxic activity on breast and liver cancer cell lines. The carotenoid rich fraction of H. pluvialis was analysed using LC‐DAD/ESI‐MS and the major carotenoids were identified either free as well as bounded to fatty acids.     

β‐Bisabolene,a Sesquiterpene from the Essential Oil Extract of Opoponax (Commiphora guidottii), Exhibits Cytotoxicity in Breast Cancer Cell Lines

The essential oils from Commiphora species have for centuries been recognized to possess medicinal properties. Here, we performed gas chromatography‐mass spectrometry on the essential oil from opoponax (Commiphora guidotti) and identified bisabolene isomers as the main constituents of this essential oil. Opoponax essential oil, a chemical component; β‐bisabolene and an alcoholic analogue, α‐bisabolol, were tested for their ability to selectively kill breast cancer cells. Only β‐bisabolene, a sesquiterpene constituting 5% of the essential oil, exhibited selective cytotoxic activity for mouse cells (IC₅₀ in normal Eph4: >200 µg/ml, MG1361: 65.49 µg/ml, 4T1: 48.99 µg/ml) and human breast cancer cells (IC₅₀ in normal MCF‐10A: 114.3 µg/ml, MCF‐7: 66.91 µg/ml, MDA‐MB‐231: 98.39 µg/ml, SKBR3: 70.62 µg/ml and BT474: 74.3 µg/ml). This loss of viability was because of the induction of apoptosis as shown by Annexin V‐propidium iodide and caspase‐3/7 activity assay. β‐bisabolene was also effective in reducing the growth of transplanted 4T1 mammary tumours in vivo (37.5% reduction in volume by endpoint). In summary, we have identified an anti‐cancer agent from the essential oil of opoponax that exhibits specific cytotoxicity to both human and murine mammary tumour cells in vitro and in vivo, and this warrants further investigation into the use of β‐bisabolene in the treatment of breast cancers. Copyright © 2015 John Wiley & Sons, Ltd.     

赤豆的雌激素样作用及其对人类乳腺癌MCF-7细胞孕激素受体水平的影响

目的：评价赤豆的雌激素样作用及其对人类乳腺癌MCF-7细胞孕激素受体水平的影响。方法：采用富含雌激素受体的雌激素依赖性人乳腺癌细胞株MCF-7细胞，分别以E-SCREEN法观察赤豆提取物对其增殖的影响，以RT-PCR法、Western blot法观察赤豆对孕激素受体mRNA和蛋白表达的影响，并以雌激素受体拮抗剂ICI182,780为工具药来评价赤豆提取物发挥雌激素样作用的机制。结果：与溶剂对照组比较，赤豆（10～200 μg·mL^-1）能显著促进MCF-7细胞的增殖，100 μg·mL^-1时作用达到最大；赤豆提取物能明显诱导MCF-7细胞孕激素受体(PR)基因mRNA和蛋白的表达，以上作用均能被雌激素受体拮抗剂所完全拮抗。结论：赤豆提取物具有雌激素活性，此作用是通过雌激素受体(ER)介导的。     

Barbigerone reverses multidrug resistance in breast MCF‐7/ADR cells

Development of agents to overcome multidrug resistance (MDR) is one of the important strategies in cancer chemotherapy, and P‐glycoprotein (P‐gp) correlates with the degree of resistance. As a naturally occurring isoflavone, whether barbigerone (BA) could reverse MDR, is unknown. In this paper, we evaluated effects of BA on reversing P‐gp mediated MDR of adriamycin (ADR)‐resistant human breast carcinoma (MCF‐7/ADR) cells. BA (0.5 μM) treatment showed strong potency to increase ADR cytotoxicity toward MCF‐7/ADR cells. It was also demonstrated that BA time‐ and dose‐dependently increased accumulations of ADR and reduced the efflux in MCF‐7/ADR cells, pretreatment of these cells with BA might relocalized ADR to the nuclei. Furthermore, the results also revealed that BA did not affect P‐gp, but alter P‐gp ATPase activity. Intravenous administration of BA significantly increased anticancer efficacy of ADR to MCF‐7/ADR xenograft model in nude mice. These results revealed that BA might reverse P‐gp mediated MDR through inhibition of ATPase activity, which indicated a novel use of BA as a potent candidate for cancer chemotherapy.