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.     

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.     

Growth inhibition and cell cycle arrest in the G0/G1 by schizandrin,a dibenzocyclooctadiene lignan isolated from Schisandra chinensis,on T47D human breast cancer cells

Schizandrin is one of the main dibenzocyclooctadiene lignans present in the fruit of Schisandra chinensis (Schisandraceae). Biological activities including hepatoprotective, antiviral and neuroprotective effects of schizandrin and other dibenzocyclooctadiene lignans have been reported previously. However, the antiproliferative effect of schizandrin against human cancer cells has been poorly determined to date. This study examined the antiproliferative effect of schizandrin in human breast cancer cells. Schizandrin exhibited growth inhibitory activities in cultured human breast cancer cells, and the effect was the more profound in estrogen receptor (ER)‐positive T47D cells than in ER‐negative MDA‐MB‐231 cells. When treated with the compound in T47D cells, schizandrin induced the accumulation of a cell population in the G0/G1 phase, which was further demonstrated by the induction of CDK inhibitors p21 and p27 and the inhibition of the expression of cell cycle checkpoint proteins including cyclin D1, cyclin A, CDK2 and CDK4. These results suggest that schizandrin inhibits cell proliferation through the induction of cell cycle arrest with modulating cell cycle‐related proteins in human breast cancer cells. Copyright © 2009 John Wiley & Sons, Ltd.     

蓝萼甲素对三阴性乳腺癌MDA-MB-231细胞增殖及细胞周期的影响

目的研究蓝萼甲素对三阴性乳腺癌MDA-MB-231细胞增殖及细胞周期的影响及其作用机制。方法采用MTT法检测蓝萼甲素对MDA-MB-231细胞增殖的影响;流式细胞仪检测细胞周期;Western blotting法检测细胞中cyclin B1、cyclin D1、细胞周期素依赖激酶2(CDK2)、CDK4、p53、p21、p27、组蛋白赖氨酸特异性去甲基化酶1(LSD1)、组蛋白H3第4位赖氨酸二甲基化(H3K4me2)、组蛋白H3第9位赖氨酸二甲基化(H3K9me2)蛋白表达水平。结果蓝萼甲素能显著抑制MDA-MB-231细胞的增殖,呈剂量和时间依赖性;提高G2/M期细胞比例;上调p53、p21、p27、H3K4me2、H3K9me2蛋白表达水平,下调cyclin B1、cyclin D1、CDK2、CDK4、LSD1蛋白表达水平。结论蓝萼甲素抑制MDA-MB-231细胞增殖,阻滞MDA-MB-231细胞周期于G2/M期,其机制可能与激活p53的表达及调控组蛋白的甲基化作用有关。     

Furanodiene Presents Synergistic Anti‐proliferative Activity With Paclitaxel Via Altering Cell Cycle and Integrin Signaling in 95‐D Lung Cancer Cells

Furanodiene (FUR) is a natural terpenoid isolated from Rhizoma Curcumae, a well‐known Chinese medicinal herb that presents anti‐proliferative activities in several cancer cell lines. Recently, we found that the combined treatment of FUR with paclitaxel (TAX) showed synergetic anti‐proliferative activities in 95‐D lung cancer cells. Herein, we showed that FUR reduced the cell numbers distributed in mitosis phase induced by TAX while increased those in G1 phase. The protein levels of cyclin D1, cyclin B1, CDK6 and c‐Myc were all down‐regulated in the group of combined treatment. The dramatically down‐regulated expression of integrin β4, focal adhesion kinase and paxillin might partially contribute to the synergic effect. Though FUR alone obviously induced endoplasmic reticulum stress, this signaling pathway may not contribute to the synergetic anti‐proliferative effect as the protein expression of CHOP and BIP was similar in FUR alone and combined treatment group. Copyright © 2013 John Wiley & Sons, Ltd.     

Nobiletin,a Polymethoxylated Flavone,Inhibits Glioma Cell Growth and Migration via Arresting Cell Cycle and Suppressing MAPK and Akt Pathways

Nobiletin, a bioactive polymethoxylated flavone (5,6,7,8,3^',4^'‐hexamethoxyflavone), is abundant in citrus fruit peel. Although nobiletin exhibits antitumor activity against various cancer cells, the effect of nobiletin on glioma cells remains unclear. The aim of this study was to determine the effects of nobiletin on the human U87 and Hs683 glioma cell lines. Treating glioma cells with nobiletin (20–100 µm ) reduced cell viability and arrested the cell cycle in the G0/G1 phase, as detected using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay and propidium iodide (PI) staining, respectively; however, nobiletin did not induce cell apoptosis according to PI‐annexin V double staining. Data from western blotting showed that nobiletin significantly attenuated the expression of cyclin D1, cyclin‐dependent kinase 2, cyclin‐dependent kinase 4, and E2 promoter‐binding factor 1 (E2F1) and the phosphorylation of Akt/protein kinase B and mitogen‐activated protein kinases, including p38, extracellular signal‐regulated kinase, and c‐Jun N‐terminal kinase. Our data also showed that nobiletin inhibited glioma cell migration, as detected by both functional wound healing and transwell migration assays. Altogether, the present results suggest that nobiletin inhibits mitogen‐activated protein kinase and Akt/protein kinase B pathways and downregulates positive regulators of the cell cycle, leading to subsequent suppression of glioma cell proliferation and migration. Our findings evidence that nobiletin may have potential for treating glioblastoma multiforme. Copyright © 2015 John Wiley & Sons, Ltd.     

Paris saponin VII induces cell cycle arrest and apoptosis by regulating Akt/MAPK pathway and inhibition of P‐glycoprotein in K562/ADR cells

Paris saponinVII (PSVII) is a steroidal saponin isolated from the roots and rhizomes of Trillium tschonoskii Maxim. We found that PSVII could inhibit the growth of adriamycin‐resistant human leukemia cells (K562/ADR) in a dose‐dependent manner. Furthermore, the molecular mechanism underlying the cytotoxicity and downregulation of P‐glycoprotein (P‐gp) expression by PSVII was clarified. PSVII significantly suppressed cell proliferation by cell cycle arrest in the G0/G1 phase, which was associated with an obvious decrease in cyclin B1/D1 and CDK2/4/6 protein expression. Moreover, PSVII could attenuate mitochondrial membrane potential, increase the expression of apoptosis‐related proteins, such as Bax and cytochrome c, and decrease the protein expression levels of Bcl‐2, caspase‐9, caspase‐3, PARP‐1, and p‐Akt. We also found that JNK, ERK1/2, and p38 were regulated by PSVII in K562/ADR cells. And further studies indicated that the decrease in the reactive oxygen species level inhibited intrinsic P‐gp expression. Therefore, PSVII‐induced apoptosis in K562/ADR cells was associated with Akt/MAPK and the inhibition of P‐gp. In addition, PSVII induced a robust autophagy in K562/ADR cells as demonstrated by the degradation of LC3‐I. These results provide a biochemical basis for possible clinical applications of PSVII in the treatment of leukemia.     

Activation of p53 signaling and inhibition of androgen receptor mediate tanshinone IIA induced G1 arrest in LNCaP prostate cancer cells

Our group previously reported that tanshinone IIA induced apoptosis via a mitochondria dependent pathway in LNCaP prostate cancer cells. In the present study, the roles of androgen receptor (AR) and p53 signaling pathways were investigated in tanshinone IIA-induced G1 arrest in LNCaP cells. Tanshinone IIA significantly inhibited the growth and proliferation of LNCaP cells by colony formation and BrdU incorporation assays, respectively. Tanshinone IIA induced cell cycle arrest at G1 phase and down-regulated cyclin D1, CDK2 and CDK4. Furthermore, tanshinone IIA activated the phosphorylation of p53 at Ser 15 residue and its downstream p21 and p27. Additionally, tanshinone IIA suppressed the expression of AR and prostate specific antigen (PSA). Conversely, silencing p53 using its specific siRNA reversed cyclin D1 expression inhibited by tanshinone IIA. However, knockdown of AR had no effect on the p53/p21/p27 signaling pathway activated by tanshinone IIA in LNCaP cells. In AR siRNA-transfected cells, tanshinone IIA did not cause cell cycle arrest and reduce cyclin D1, implying that AR is essential to induce G1 arrest by tanshinone IIA in LNCaP cells. Taken together, the findings suggest that tanshinone IIA induces G1 arrest via activation of p53 signaling and inhibition of AR in LNCaP cells.     

莪术醇抑制人肝癌细胞HepG2增殖的机制

目的:探讨莪术醇在体外对人肝癌HepG2细胞的增殖和细胞周期的影响及其分子机制.方法:体外培养HepG2细胞,采用四甲基偶氮唑蓝(MTT)比色法观察莪术醇对HepG2细胞增殖的抑制作用,流式细胞术分析莪术醇处理后HepG2细胞的周期分布,TaqMan探针实时荧光定量PCR法及Western印迹检测细胞周期调控相关基因的表达水平.结果:莪术醇对HepG2细胞的增殖具有明显抑制作用,且在一定范围内(2.5～10mg·L-1)呈浓度和时间依赖性;莪术醇诱导HepG2细胞发生G1期阻滞,伴随cyclin D1,CDK2,CDK8,pRB1,p27KIPl mRNA表达水平增高,而cyclin A1的水平则下调,cyclin E1和CDK4的表达不受影响,p53及其下游调控蛋白p21WAF1和Wip1表达水平增高.结论:莪术醇诱导人肝癌HepG2细胞G1期阻滞、抑制细胞增殖,其作用可能通过激活p53与pRB通路,抑制cyclin A1基因的表达和上调p21 WAF1,p27KIP1以及CDK8基因的表达而实现的.     

周期蛋白依赖性激酶4/6抑制剂palbociclib

周期蛋白依赖性激酶（CDK）4/6是细胞周期的关键调节因子,能够触发细胞周期从生长期（G1期）向DNA复制期（S1期）转变。在雌激素受体阳性（ER＋）乳腺癌中,CDK4/6的过度活跃非常频繁。palbocicib是一种口服的CDK4/6抑制剂,能够选择性抑制 CDK4/6,恢复细胞周期控制,阻断肿瘤细胞增殖。从Ⅱ期临床实验结果来看,palbociclib 的临床疗效具有非常明显的优势。     

Crocetin inhibits cell cycle G1/S transition through suppressing cyclin D1 and elevating p27kip1 in vascular smooth muscle cells

Crocetin is a natural carotenoid compound isolated from Gardenia jasminoids Ellis. Our previous study shows that crocetin inhibits angiotensin II (Ang II)‐induced vascular smooth muscle cells (VSMCs) proliferation. To further explore the mechanism by which crocetin inhibits VSMCs proliferation, in the present study we examined the effect of crocetin on cell cycle progression and cell cycle regulatory proteins. Flow cytometry analysis showed that Ang II elicited significant increase in the percentage of VSMCs in the S phase, with a concomitant decline in the percentage of VSMCs in the G₀/G₁ phase. However, on pretreatment of VSMCs with crocetin, the percentage of VSMCs in the S phase decreased, while that in the G₀/G₁ phase increased significantly. In addition, Ang II‐induced increase of cell proliferation index was also decreased by crocetin. Western blotting analysis indicated that crocetin markedly inhibited the protein expression of cyclin D1 but not cyclin E. Crocetin also increased the level of cyclin‐dependent kinase inhibitor (CDKI) p27^kip1 but not CDKI p21^waf1/cip1. In conclusion, our present results suggest that the inhibition of cell cycle G₁/S transition in VSMCs by crocetin can be attributed, at least in part, to its suppression of cyclin D1 and elevation of CDKI p27^kip1. Copyright © 2009 John Wiley & Sons, Ltd.     

Acylated Iridoids and Rhamnopyranoses from Premna odorata (Lamiaceae) as Novel Mesenchymal–Epithelial Transition Factor Receptor Inhibitors for the Control of Breast Cancer

Phytochemical investigation of Premna odorata Blanco, Lamiaceae, leaves afforded three new acylated iridoid glycosides 1–3 and two new acylated rhamnopyranoses 9 and 10, in addition to ten known compounds. The structures of the new compounds were confirmed using extensive 1D and 2D NMR analysis. Molecular modeling study suggested the potential of the acylated rhamnopyranoses to bind at the c‐Met kinase domain. Cell‐free Z′‐LYTE? assay testing revealed the good c‐Met phosphorylation inhibitory activity of 9, followed by 8, and 10, with IC₅₀ values of 2.5, 6.9, and 12.7 μM, respectively. The (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) cell proliferation assay testing against the human c‐Met expressing highly invasive MDA‐MB‐231 suggested compound 9 as the most active with IC₅₀ value of 13.3 μM. Testing of compound 9 against multiple phenotypic breast cancer cell lines including MCF‐7, BT‐474 cells, and MDA‐MB‐468 proved enhanced activity against the highly c‐Met expressing triple‐negative breast cancer cell lines. Acylated rhamnopyranoses are potential novel c‐Met inhibitors appropriate for future optimizations to control c‐Met‐dependent breast malignancies. Copyright © 2017 John Wiley & Sons, Ltd.     

Harmine Hydrochloride Triggers G2 Phase Arrest and Apoptosis in MGC‐803 Cells and SMMC‐7721 Cells by Upregulating p21, Activating Caspase‐8/Bid,and Downregulating ERK/Bad Pathway

This study aimed to investigate the effects of harmine hydrochloride (HMH) on digestive tumor cells in vitro and its molecular mechanism. MTT assays showed that HMH inhibited the proliferation of some human cancer cell lines and had no obvious inhibitory effects on human LO2 cells. Flow cytometry assays showed that HMH trigged G2 phase arrest in MGC‐803 cells and SMMC‐7721 cells, while the expression of cyclin A, cyclin B, p21, Myt1, and p‐cdc2 (Tyr15) was upregulated. Flow cytometry assays also showed that the percentages of apoptotic cells were increased, the mitochondrial transmembrane potential (ΔΨm) decreased, and the cleavage of caspase‐9, caspase‐3, and poly (Adenosine diphosphate ribose) polymerase (PARP) were observed, the expression of Bad increased, phospho‐Bad (S112) decreased, pro‐caspase‐8 was cleaved, and Bid (22 kDa) was cleaved. The expression of p‐ERK decreased in both cells. In conclusion, these results demonstrated that HMH upregulates the expression of p21, activates Myt1 and inhibits cdc2 by phospho‐cdc2 (Y15), and triggers G2 phase arrest in both MGC‐803 cells and SMMC‐7721 cells. It can also activate the mitochondria‐related cell apoptosis pathway through the caspase‐8/Bid pathway, inhibiting the ERK/Bad pathway and promoting apoptosis in both of these two cell types. Copyright © 2015 John Wiley & Sons, Ltd.     

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.     

Polysaccharide peptide mediates apoptosis by up-regulating p21 gene and down-regulating cyclin D1 gene

The use of herbal medicine is a common practice among Chinese women with breast cancer. Yunzhi (Voriolus versicolor), a substance that is regarded as a biological response modifier, is frequently used. The aim of the present study is to evaluate the anti-proliferative action of, Yunzhi, polysaccharide peptide (PSP), on breast cancer cells. Breast cancer cells (MDA-MB-231) were cultured with and without PSP for 7 days. Cell growth at 24, 72, 120 and 168 hours was measured by Cell Proliferation Reagent (WST-1). Cells treated with PSP were found to have a significant reduction in cell proliferation as compared to controls after 72 hours of incubation. This lasted for 168 hours. When the effect of PSP on apoptosis was studied by the TdT-mediated X-dUTP nick end-labeling (TUNEL) assay, we found that PSP had a significant effect upon apoptosis from 24 hours onward. Immunostaining showed that PSP increased p21 expression and decreased cyclin D1 expression. In conclusion, PSP is effective in inhibiting cell proliferation through apoptosis. The mechanism for the apoptosis may be through up-regulation of p21 and down-regulation of cyclin D1.