Turmeric Toxicity in A431 Epidermoid Cancer Cells Associates with Autophagy Degradation of Anti‐apoptotic and Anti‐autophagic p53 Mutant

The keratinocyte‐derived A431 Squamous Cell Carcinoma cells express the p53R273H mutant, which has been reported to inhibit apoptosis and autophagy. Here, we show that the crude extract of turmeric (Curcuma longa), similarly to its bioactive component Curcumin, could induce both apoptosis and autophagy in A431 cells, and these effects were concomitant with degradation of p53. Turmeric and curcumin also stimulated the activity of mTOR, which notoriously promotes cell growth and acts negatively on basal autophagy. Rapamycin‐mediated inhibition of mTOR synergized with turmeric and curcumin in causing p53 degradation, increased the production of autophagosomes and exacerbated cell toxicity leading to cell necrosis. Small‐interference mediated silencing of the autophagy proteins BECLIN 1 or ATG7 abrogated the induction of autophagy and largely rescued p53 stability in Turmeric‐treated or Curcumin‐treated cells, indicating that macroautophagy was mainly responsible for mutant p53 degradation. These data uncover a novel mechanism of turmeric and curcumin toxicity in chemoresistant cancer cells bearing mutant p53. Copyright © 2014 John Wiley & Sons, Ltd.     

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.     

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.     

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.     

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.     

Celastrol inhibits growth and metastasis of human gastric cancer cell MKN45 by down‐regulating microRNA‐21

Celastrol could inhibit cancer cell growth in vitro. However, effect(s) of celastrol on gastric cancer is not well studied. Therefore, we investigated the effects of celastrol on human gastric cancer cell line MKN45 and the underlying mechanisms. We found that celastrol inhibited cell proliferation, migration, and invasion and induced cell apoptosis and G2/M cell cycle arrest (p < .05, p < .01, or p < .001). Under celastrol treatment, overexpression of microRNA‐21 (miR‐21) increased cell viability, migration, and invasion and inhibited cell apoptosis compared with negative control (p < .05, p < .01, or p < .001). In addition, the phosphorylation of PTEN was significantly up‐regulated, whereas PI3K, AKT, p65, and IκBα phosphorylation was statistically decreased by celastrol (p < .05 or p < .01) and then further reversed by miR‐21 overexpression (p < .05 or p < .01). On the other side, miR‐21 silence showed contrary results (p < .05) as relative to miR‐21 overexpression. In conclusion, celastrol inhibits proliferation, migration, and invasion and inactivates PTEN/PI3K/AKT and nuclear factor κB signaling pathways in MKN45 cells by down‐regulating miR‐21.     

姜黄素抑制乳腺癌细胞株Survivin表达及其增殖的影响

目的:探讨姜黄素对乳腺癌细胞株MCF-7中Survivin表达及其增殖的影响。方法:采用CCK-8法检测姜黄素对MCF-7细胞增殖的影响;real-time PCR、Western blot检测姜黄素作用于MCF-7细胞前后,Survivin在m RNA和蛋白水平的表达。结果:姜黄素可显著抑制乳腺癌细胞株MCF-7的增殖,并呈浓度依赖性,姜黄素处理48小时的IC50值为6.4μM。同时Survivine在基因及蛋白的水平表达均显著降低(P0.05),20μM组较10μM组下降明显(P0.05)。结论:姜黄素可以抑制乳腺癌细胞株MCF-7的增殖,其机制可能与下调Survivin表达相关。     

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.     

Combination of tanshinone IIA and doxorubicin possesses synergism and attenuation effects on doxorubicin in the treatment of breast cancer

Doxorubicin (Dox) is a first‐line drug for breast cancer chemotherapy. However, with the prolongation of chemotherapy cycle, breast cancer cells are increasingly tempt to resist Dox, and meanwhile, high cumulative dose of Dox brings enhancing toxic side effects, and these effects may lead to chemotherapy failure. Hence, it is necessary to search an agent in combination medication with Dox, which can not only enhance the chemosensitivity of Dox but also reduce the toxic side effects. Tanshinone IIA (Tan IIA) is reported to have antitumor activity in addition to its cardiovascular protective effects. We employed human breast cancer MCF‐7 and MCF‐7/dox cells in order to assess whether Tan IIA might perform such function. Our in vitro studies showed that Tan IIA could enhance the sensitivity of breast cancer cells to Dox through inhibiting the PTEN/AKT pathway and downregulating the expression of efflux ABC transporters including P‐gp, BCRP, and MRP1. In addition, our in vivo studies showed Tan IIA enhanced the chemotherapeutic effect of Dox against breast cancer while reducing its toxic side effects including weight loss, myelosuppression, cardiotoxicity, and nephrotoxicity. Therefore, Tan IIA could be used as a novel agent combined with Dox in breast cancer therapy.     

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.     

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.     

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.     

Fangchinoline Induces G1 Arrest in Breast Cancer Cells Through Cell‐Cycle Regulation

Fangchinoline, an alkaloid derived from the dry roots of Stephaniae tetrandrine S. Moore (Menispermaceae), has been shown to possess cytotoxic, anti‐inflammatory, and antioxidant properties. In this study, we used Fangchinoline to inhibit breast cancer cell proliferation and to investigate its underlying molecular mechanisms. Human breast cancer cell lines, MCF‐7 and MDA‐MB‐231, were both used in this study. We found that Fangchinoline significantly decreased cell proliferation in a dose‐dependent manner and induced G1‐phase arrest in both cell lines. In addition, upon analysis of expression of cell cycle‐related proteins, we found that Fangchinoline reduced expression of cyclin D1, cyclin D3, and cyclin E, and increased expression of the cyclin‐dependent kinase (CDK) inhibitors, p21/WAF1, and p27/KIP1. Moreover, Fangchinoline also inhibited the kinase activities of CDK2, CDK4, and CDK6. These results suggest that Fangchinoline can inhibit human breast cancer cell proliferation and thus may have potential applications in cancer therapy. Copyright © 2013 John Wiley & Sons, Ltd.     

姜黄素作用PTEN/PI3K/AKT通路诱导膀胱癌EJ细胞凋亡

目的:研究姜黄素抗癌作用的分子机制。方法:以人膀胱癌细胞株EJ为模型,采用MTT法、流式细胞术,检测姜黄素对EJ细胞生长和凋亡的影响,并通过Western Blotting法检测姜黄素对EJ细胞PTEN/PI3K/AKT通路凋亡相关蛋白表达的影响。结果:姜黄素以浓度及时间依赖的方式抑制EJ细胞的增殖;流式细胞仪检测发现姜黄素作用于EJ细胞24 h后凋亡率呈剂量依赖性增加。Western Blotting显示50μM姜黄素作用EJ细胞后,PTEN、GSK-3β、C-raf、Bad、caspase-9、caspase-3的活性增强,PARP的裂解增加和Akt、PDK1的表达水平降低。结论:姜黄素能增加EJ细胞PTEN的表达,进而抑制PI3K/Akt信号通路的激活,继之激活下游GSK-3β,caspase-9和Bad等多种促凋亡分子的表达,诱导EJ细胞发生凋亡。该研究表明PTEN/PI3K/Akt信号通路在姜黄素诱导的EJ膀胱癌细胞凋亡中起了重要作用。     

The Puzzling Issue of ‘Vehicle‐Treated Control’ when Using Ethanol as Drug Carrier for MCF‐7 Cells

Ethanol has been commonly used as a vehicle for drug discovery purpose in vitro. The human breast cancer MCF‐7 estrogen dependent cell line is a common in vitro model used for hormonal therapy study. However, special precaution is suggested when ethanol is used in pharmacological tests as solvent in order to evaluate the biological activity of potential drugs especially concerning about the MCF‐7. Ethanol was shown to stimulate the proliferation of this estrogen receptor positive cell line. Here, we have further demonstrated that the dose responsive stimulatory effect of ethanol on the MCF‐7 cells after pre‐incubating the breast carcinoma cells with phenol red‐free medium and stripped fetal bovine serum. Our findings open a discussion for the evaluation of ethanol as solvent for drug discovery and screening when using MCF‐7 cells as a testing model. Copyright © 2014 John Wiley & Sons, Ltd.     

Betanin‐Enriched Red Beetroot (Beta vulgaris L.) Extract Induces Apoptosis and Autophagic Cell Death in MCF‐7 Cells

Recent studies have pointed out the preventive role of beetroot extracts against cancers and their cytotoxic activity on cancer cells. Among many different natural compounds, these extracts contained betanin and its stereoisomer isobetanin, which belongs to the betalain group of highly bioavailable antioxidants. However, a precise identification of the molecules responsible for this tumor‐inhibitory effect was still required. We isolated a betanin/isobetanin concentrate from fresh beetroots, corresponding to the highest purified betanin extract used for studying anticancer activities of these molecules. The cytotoxicity of this betanin‐enriched extract was then characterized on cancer and normal cells and we highlighted the death signalling pathways involved. Betanin/isobetanin concentrate significantly decreased cancer cell proliferation and viability. Particularly in MCF‐7‐treated cells, the expressions of apoptosis‐related proteins (Bad, TRAILR4, FAS, p53) were strongly increased and the mitochondrial membrane potential was altered, demonstrating the involvement of both intrinsic and extrinsic apoptotic pathways. Autophagosome vesicles in MCF‐7‐treated cells were observed, also suggesting autophagic cell death upon betanin/isobetanin treatment. Importantly, the betanin‐enriched extract had no obvious effect towards normal cell lines. Our data bring new insight to consider the betanin/isobetanin mix as therapeutic anticancer compound, alone or in combination with classical chemotherapeutic drugs, especially in functional p53 tumors. Copyright © 2015 John Wiley & Sons, Ltd.