小白菊内酯对U-87 MG细胞增殖和凋亡的影响及其机制研究

目的考察小白菊内酯对于人脑恶性胶质瘤细胞U-87 MG细胞系的增殖、细胞周期及凋亡的影响,并探讨其作用机制.方法采用CCK-8比色法和克隆形成检测法检测小白菊内酯对U-87 MG的增殖抑制作用;采用碘化丙啶(PI)染色后的流式细胞仪检测小白菊内酯处理前后对细胞周期、凋亡的影响;采用qPCR以及Western blotting法研究药物处理后U-87 MG细胞的Caspase 3、Bax、Cyclin D1的表达变化以及P53-Ser392蛋白质磷酸化激活.结果小白菊内酯可明显抑制U-87 MG的细胞增殖、克隆形成数量及克隆大小.处理48 h后,U-87 MG细胞的S期、G2/M期受到了阻滞,G0/G1期细胞比例明显减少,同时细胞的凋亡也明显增多.Caspase 3、Bax基因的mRNA及蛋白表达明显上升,而Cyclin D1基因的mRNA表达明显下降.同时P53-Ser392残基的磷酸化水平也明显上升.结论 小白菊内酯可通过调节P53基因的Ser392残基磷酸化抑制其下游的细胞凋亡、细胞周期途径上Caspase 3、Bax、Cyclin D1的基因表达,影响细胞周期及凋亡,从而抑制肿瘤细胞的增殖.     

Emodin induces cytotoxic effect in human breast carcinoma MCF-7 cell through modulating the expression of apoptosis-related genes

Abstract

Context: The poor prognostic outcome of breast cancer is largely due to its resistance to cancer therapies. Development of therapeutic agents that can inhibit growth and induce apoptosis in breast cancer cells can help solve the problem. Emodin is an active anthraquinone that has been reported to have diverse biological effects.

Objective: In this study, the anticancer effects of emodin on growth inhibition, apoptosis induction and the expression of apoptosis-related genes in MCF-7 cells were investigated.

Materials and methods: Growth inhibition induced by emodin was investigated by the MTS assay and the colony formation assay; while emodin-induced apoptosis was determined by the COMET assay and DNA fragmentation detection. Emodin (35?μM)-induced alterations in the expression of apoptotic-related genes were detected by using real-time PCR.

Results: Emodin had significant growth inhibitory effects on MCF-7 cells with IC₅₀?=?7.22?µg/ml (～30?μM). It also exerted a concentration-dependant inhibitory effect on the colony-forming ability of MCF-7 cells with IC₅₀?=?7.60?µg/ml (～30?µM). Hallmarks of apoptosis, such as single-strand DNA breakage and DNA fragmentation, were observed in emodin-treated MCF-7 cells. The gene expression of Fas ligand (FASL) was up-regulated (p?<?0.01) but those of MCL1, CCND1 and C-MYC were down-regulated (p?<?0.05) in emodin-treated MCF-7 cells.

Discussion and conclusion: This study indicated that emodin could induce growth inhibition and apoptosis in MCF-7 cells through the modulation of the expression of apoptosis-related genes. The growth inhibitory effects of emodin might involve both the intrinsic and the extrinsic apoptotic pathways and cell cycle arrest.     

In vitro and in vivo antitumour activities of puerarin 6″-O-xyloside on human lung carcinoma A549 cell line via the induction of the mitochondria-mediated apoptosis pathway

Context Pueraria lobata (Leguminoseae) shows cytotoxic effects against cancer cells; however, its active components remain unclear.

Objective This study investigated the antitumour activity of puerarin 6″-O-xyloside (POS) on the human lung carcinoma A549 cell line.

Materials and methods The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the cytotoxicity of POS (at 10, 20 and 40?μM) in vitro, and xenograft nude mice were established to evaluate the antitumour effect of POS (at 40?mg/kg/d) in vivo by 15 days intraperitoneal injection (ip). To explore its mechanism of action, flow cytometry was performed to determine the pro-apoptotic effect of POS (at 10, 20 and 40?μM). Subsequently, the expression of caspase-3, caspase-7, caspase-9, Bcl-2 and Bax in A549 cells were determined.

Results POS showed significant cytotoxicity toward A549 cells (p?<?0.05) by inducing apoptosis. Treatment with POS significantly upregulated the levels of caspase-3 (p?<?0.01), caspase-7 (p?<?0.01), caspase-9 (p?<?0.01) and Bax (p?<?0.01) in A549 cells, and Bcl-2 was downregulated (p?<?0.01). Additionally, the in vivo animal study showed that POS significantly inhibited tumour growth in A549 cells (p?<?0.01).

Conclusion Our study demonstrated the POS has significant antitumour activities. The mechanisms are related to increased levels of caspase-3, caspase-7, caspase-9 and Bax, and reduced levels Bcl-2.     

Isolation and identification of three new chromones from the leaves of Pimenta dioica with cytotoxic,oestrogenic and anti-oestrogenic effects

Context: Pimenta dioica (L.) Merr. (Myrtaceae) is used in Costa Rican traditional medicine for women’s health. Our previous work showed that P. dioica extracts were oestrogenic.

Objectives: This work identifies phytochemicals from P. dioica that are responsible for the plant’s oestrogen-like activities.

Materials and methods: P. dioica leaves were collected in Costa Rica in 2005. Fractions resulting from chromatographic separation of a methanol extract were tested at 50?μg/mL in a competitive oestrogen receptor-binding assay. Active compounds were isolated by HPLC and identified by NMR and MS. Pure compounds were tested at 1?μM in the oestrogen-responsive SEAP reporter gene assay. The effects on cell viability, cytotoxicity and apoptosis were investigated in breast cancer (MCF-7 and SK-BR3) and gastric cancer (AGS and NCI-N87) cell lines using the ApoTox-Glo and Caspase-Glo assays and qPCR.

Results: Quercitrin and three new chromones, including a 2-phenoxychromone, 6,8-di-C-methylcapillarisin (1) were isolated and identified. Compound 1 caused a 6.2-fold increase in SEAP expression at 1?μM (p?2 caused a 6.0-fold increase in SEAP, inhibited the growth of MCF-7, AGS and NCI-N87 cells (IC₅₀ 54.27, 38.13 and 51.22?μg/mL, respectively), and induced apoptosis via caspase 8 and increased the Bax/Bcl-2 mRNA ratio in MCF-7 cells. Compound 3 was anti-oestrogenic in MCF-7 cells.

Discussion and conclusions: Compounds from P. dioica have oestrogenic, anti-oestrogenic and cytotoxic effects that may explain the ethnomedical use of this plant.     

Annosquacin B induces mitochondrial apoptosis in multidrug resistant human breast cancer cell line MCF-7/ADR through selectively modulating MAPKs pathways

Context: Multidrug resistance (MDR) is a major obstacle to efficient therapy of cancers. It is a prime concern for researchers to find compounds with anti-proliferative activity on MDR cell lines. In recent years, annonaceous acetogenins (ACGs) were reported to have anti-proliferative activity. However, the underlying mechanisms are still unknown.

Objective: This study determines the mechanisms of anti-proliferative activity induced by Annosquacin B (AB) against MCF-7/ADR cells.

Material and methods: The cytotoxicity of AB at varying concentrations (0.64, 1.6, 4, 10, 25, 62.5, 156.25?μM) on MCF-7/ADR cells was assessed using the MTT assay. Annexin V-FITC/propidium iodide staining and Acrinidine orange and ethidium bromide (AO/EB) staining were employed to investigate whether AB (14, 7, 3.5?μM) could induce apoptosis in MCF-7/ADR cells. Levels of caspase-3 and caspase-9, Bax, Bcl-2 and MAPKs kinases were evaluated by western blot assay following treatment with various concentrations of AB (3.5, 7, 14?μM) at different time points (0, 0.5, 1, 2, 4, 8, 12?h).

Results and conclusion: MTT assay showed that AB significantly decreased cell viability on MCF-7/ADR (IC₅₀ of 14.69?μM). AB-induced apoptosis in MCF-7/ADR cells through mitochondrial apoptosis pathways. It induced typical apoptosis by morphologic changes; elevate levels of caspase-3, caspase-9 as well as the ratio of Bax/Bcl-2. In addition, AB increased the expression of p-p38 MAPK and decreased the expression of p-JNK, while whether ERK1/2 had an effect on the MCF-7/ADR apoptosis remains to be determined.     

Effect of proliferation,cell cycle,and Bcl-2s of MCF-7 cells by resveratrol

Our goals were to examine the dual-directional regulation effects of resveratrol (1) in vitro by using MCF-7 cells (estradiol receptor-positive cells), study its mechanism of action, and give a systematical analysis of the regulatory networks of each related factor. An MTT test and growth curve showed that the proliferation of MCF-7 cells was inhibited by a high concentration of 1, and that its IC₅₀ was 8.70 × 10^? 5 ± 0.23 mol/l. However, 1 induced the proliferation of MCF-7 cells at 10^? 7–10^? 5 mol/l, and resulted in a peak proliferation at 1.0 × 10^? 7 mol/l. A high concentration of 1 arrested cell cycle progression at the G₁ phase, and a typical “sub-G₁ peak” of apoptotic cells was also observed by flow cytometry. The proliferation index of MCF-7 cells increased significantly with a low concentration of 1 (p < 0.05). 1 in high concentrations induced Bax, caspase-3, and cyclin-dependent kinase (CDK) inhibitor P21 expression, whereas the expressions of cyclin CDK2, Bcl-2, and proliferating cell nuclear antigen (PCNA) were decreased by 1 treatment. Conversely, treatment with low concentrations of 1 decreased the expression of P21 and Bax, while the expressions of cyclin CDK2, Bcl-2, and PCNA were increased. These results suggest that 1 had a dual-regulatory effect on MCF-7 cells. CDK-associated protein was a key factor at both the high and low concentrations used in this study.     

Combined effect of Hsp90 inhibitor geldanamycin and parthenolide via reactive oxygen species-mediated apoptotic process on epithelial ovarian cancer cells

Hsp90 inhibitor geldanamycin and parthenolide have been shown to induce apoptosis in cancer cells. However, the combined effect of geldanamycin and parthenolide on epithelial ovarian cancer cells has not been studied. In respect of cell death process, we investigated the promoting effect of parthenolide on geldanamycin-induced apoptosis in the human epithelial ovarian carcinoma cell lines OVCAR-3 and SK-OV-3. Geldanamycin induced a decrease in Bid, Bcl-2, Bcl-xL and survivin protein levels; an increase in Bax and tumour suppressor p53 levels; loss of the mitochondrial transmembrane potential; cytochrome c release; activation of caspases (-8, -9 and -3); cleavage of PARP-1; and increase in the reactive oxygen species formation. Parthenolide enhanced geldanamycin-induced changes in the apoptosis-related protein levels, reactive oxygen species formation, nuclear damage and cell death. The combined effect was inhibited by the addition of oxidant scavengers. The results suggest that parthenolide may potentiate the apoptotic effect of geldanamycin on ovarian carcinoma cell lines by the activation of the caspase-8- and Bid-dependent pathway and the mitochondria-mediated apoptotic pathway. The apoptosis-promoting effect seems to be mediated by the stimulatory effect on the formation of reactive oxygen species.     

The antitumour effects of eudesmin on lung cancer by inducing apoptosis via mitochondria-mediated pathway in the tumour cells

Context: Limonoids possess broad range of biological activities, including antitumour, antimicrobial and antioxidant activities, etc. Eudesmin (EDN) is a type of limonoid which also possesses various activities. However, there is no report on the antitumour lung cancer (LC) activities of this compound.

Objective: The present study investigates the antitumour effects of EDN and its potential molecular mechanisms.

Materials and methods: The in vitro antitumour effects of EDN on LC A549 cells were evaluated by using MTT assay. The in vivo antitumour effects were investigated on a xenograft athymic nude mouse model. The mice were administered orally with EDN (10, 20 and 40?mg/kg) once daily for 28 days. Effects of EDN on apoptosis-related or signalling proteins (Bcl-2, Bax, caspase-3, caspase-9, P53, Akt and JNK) were assayed by western blot analysis.

Results: EDN showed significant inhibitory effects on the growth of LC A549 cells in vitro with the half maximal inhibitory concentration (IC₅₀) of 18.3?μM. By treating with EDN (10, 20 and 40?μM), expression of caspase-3, caspase-9, Bax, P53 and phosphorylated JNK in A549 cells were significantly upregulated, whereas expression of Bcl-2 and Akt phosphorylation were significantly down-regulated. Interestingly, EDN-induced apoptosis could be attenuated by JNK inhibitor. In addition, in vivo experiments also indicated EDN (10, 20 and 40?mg/kg) had significant antitumour effects (p?Conclusions: Overall, the results indicated that EDN possesses significant antitumour effects on LC and the possible mechanism might be related to induction of mitochondria-mediated apoptosis.     

Schizandra chinensis extracts induce apoptosis in human gastric cancer cells via JNK/p38 MAPK activation and the ROS-mediated/mitochondria-dependent pathway

Abstract

Context: Schizandra chinensis Baill (Magnoliaceae) fruit extract (SCE) is considered a traditional herbal medicine for the treatment and alleviation of various diseases. Gastric cancer is the second most common cause of cancer-related death worldwide, and the first most common in Korea.

Objectives: This study investigates the mechanism of SCE-induced apoptosis in AGS human gastric cancer cells.

Materials and methods: SCE concentrations from 100 to 400?µg/ml were used. Cell viabilities were determined using MTT assay. Members of the Bcl-2 family and Bax were detected by Western blotting. RT-PCR was performed to measure the expression level of the Fas/FasL pro-apoptotic genes.

Results: SCE inhibited the proliferation AGS cells for 24 or 72?h (inhibition by 3.1%?±?5.2% at 100?µg/ml and 87.3%?±?7.6% at 400?µg/ml at 24?h and by 40.2%?±?5.3% 100?µg/ml and 95.3%?±?1.3% 400?µg/ml at 72?h) and increased the sub-G1 phase (25.3%?±?5.2% at 100?µg/ml and 370.2%?±?7.2% at 400?µg/ml) and the mitochondrial membrane depolarization (11.2%?±?2.1% at 100?µg/ml and 311.5%?±?6.1% at 400?µg/ml). The SCE-induced apoptotic cell death showed the down-regulation of Bcl-2, but up-regulation of Bax. Subsequently, SCE increased the expression level of Fas/FasL, activated caspase-9 and -3, and increased reactive oxygen species generation. Also, JNK II inhibitor or a p38 MAPK inhibitor inhibited SCE-induced cell death.

Discussion and conclusion: These results indicate that SCE might be an effective chemotherapeutic for the treatment of human gastric cancer.     

Fusogenic pH sensitive liposomal formulation for rapamycin: Improvement of antiproliferative effect

Context: Liposomes are increasingly employed to deliver chemotherapeutic agents, antisense oligonucleotides, and genes to various therapeutic targets.

Objective: The present investigation evaluates the ability of fusogenic pH-sensitive liposomes of rapamycin in increasing its antiproliferative effect on human breast adenocarcinoma (MCF-7) cell line.

Materials and methods: Cholesterol (Chol) and dipalmitoylphosphatidylcholine (DPPC) (DPPC:Chol, 7:3) were used to prepare conventional rapamycin liposomes by a modified ethanol injection method. Dioleoylphosphatidylethanolamine (DOPE) was used to produce fusogenic and pH-sensitive properties in liposomes simultaneously (DPPC:Chol:DOPE, 7:3:4.2). The prepared liposomes were characterized by their size, zeta potential, encapsulation efficiency percent (EE%), and chemical stability during 6 months. The antiproliferative effects of both types of rapamycin liposomes (10, 25, and 50?nmol/L) with optimized formulations were assessed on MCF-7 cells, as cancerous cells, and human umbilical vein endothelial cells (HUVEC), as healthy cells, employing the diphenyltetrazolium bromide (MTT) assay for 72?h.

Results and discussion: The particle size, zeta potential, and EE% of the liposomes were 165?±?12.3 and 178?±?15.4?nm, ?39.6?±?1.3, and ?41.2?±?2.1?mV as well as 76.9?±?2.6 and 76.9?±?2.6% in conventional and fusogenic pH-sensitive liposomes, respectively. Physicochemical stability results indicated that both liposome types were relatively stable at 4?°C than 25?°C. In vitro antiproliferative evaluation showed that fusogenic pH-sensitive liposomes had better antiproliferative effects on MCF-7 cells compared to the conventional liposomes. Conversely, fusogenic pH-sensitive liposomes had less cytotoxicity on HUVEC cell line.     

Apoptotic role of natural isothiocyanate from broccoli (Brassica oleracea italica) in experimental chemical lung carcinogenesis

Abstract

Context: Sulforaphane (SFN) [1-isothiocyanato-4-(methylsulfinyl)butane] is a naturally occurring isothiocyanate found in cruciferous vegetables such as broccoli [Brassica oleracea L. var. italica Plenck. (Brassicaceae)]. Since it is among the most potent bioactive components with antioxidant and antitumor properties, it has received intense attention in the recent years for its chemopreventive properties.

Objective: The present work determined the rehabilitating role in alleviating the oxidative damage caused by benzo(a)pyrene [B(a)P] to biomolecules and the apoptotic cascade mediated by orally administered isothiocyanate-SFN (9?µmol/mouse/day) against B(a)P (100?mg/kg body weight, i.p.) induced pulmonary carcinogenesis in Swiss albino mice.

Materials and methods: Oxidative damage was assessed by measuring lipid peroxidation, 8-hydroxydeoxyguanosine, hydrogen peroxide (H₂O₂) production, glycoprotein components, protein carbonyl levels and DNA-protein crosslinks. DNA fragmentation by agarose gel electrophoresis and caspase-3 activity by ELISA proved apoptotic induction by SFN along with the protein expression of Bcl-2, Bax and Cyt c.

Results: SFN treatment was found to decrease the H₂O₂ production (p?<?0.001) in cancer induced animals, proving its antioxidant potential. Apoptosis was induced by increasing the release of Cyt c (p?<?0.001) from mitochondria, decreasing and increasing the expression of Bcl-2 (p?<?0.01) and Bax (p?<?0.001), respectively. Caspase-3 activity was also enhanced (p?<?0.001) which leads to DNA fragmentation in SFN treated groups.

Conclusion: Our results reflect the rehabilitating role of SFN in B(a)P induced lung carcinogenesis.     

Novel anticancer alkene lactone from Persea americana

Abstract

Context: Persea americana Mill (Lauraceae) root bark is used in ethnomedicine for a variety of diseases including cancer.

Objective: To isolate and characterize the chemical constituent in P. americana, and also to determine the anticancer property of a new alkene lactone from the root bark of P. americana.

Materials and methods: The MCF-7 cells were treated with different concentrations of the pure compound for 48?h. The percentage of cells in the various phases, online monitoring of metabolic changes and integrin receptor expression determined by flow cytometry.

Results: One novel alkene lactone (4-hydroxy-5-methylene-3-undecyclidenedihydrofuran-2 (3H)-one) (1) was isolated and characterized using 1D-NMR, 2D-NMR, infrared, UV and MS. At a concentration of 10?µg/mL, significant reduction of proliferation of MCF-7 was induced while MCF-12?A cell was significantly stimulated by 10?µg/mL. The IC₅₀ value for MCF-7 cells is 20.48?µg/mL. Lower concentration of 1 harbor no significant effect on either MCF-7 or MCF-12A. The apoptotic rates of MCF-7 cells were increased significantly. At the final concentration 10?µg/mL, up to 80% of all breast cancer cells were dead. On the non-tumorigenic cell line MCF-12A, the same concentrations (1 and 10?µg/mL) of compound 1 caused significant enhanced apoptotic rates. A total of 1?µg/mL of 1 caused a decrease of α4-, α6-, β1- and β3-integrin expression.

Conclusions: The compound caused a stimulatory effect on non-tumorigenic MCF-12A cells with respect to cell adhesion while tumorigenic MCF-7 cells detached continuously. This is the first report on the anticancer effects of this class of compound.     

Thymoquinone from Nigella sativa was more potent than cisplatin in eliminating of SiHa cells via apoptosis with down-regulation of Bcl-2 protein

Thymoquinone (TQ), the active constituent of Nigella sativa or black cumin exhibited cytotoxic effects in several cancer cell lines. In this study, the cytotoxicity of TQ in human cervical squamous carcinoma cells (SiHa) was investigated. TQ was cytotoxic towards SiHa cells with IC50 values of 10.67 ± 0.12 and 9.33 ± 0.19 μg/mL as determined by MTT assay and trypan blue dye exclusion test, respectively, after 72 h of incubation. TQ was more cytotoxic towards SiHa cells compared to cisplatin. Interestingly, TQ was less cytotoxic towards the normal cells (3T3-L1 and Vero). Cell cycle analysis performed by flowcytometer showed a significant increase in the accumulation of TQ-treated cells at sub-G1 phase, indicating induction of apoptosis by the compound. Apoptosis induction by TQ was further confirmed by Annexin V/PI and AO/PI staining. Significant elevation of p53 and down-regulation of the anti-apoptotic Bcl-2 protein was found in the treated cells, without any changes in the expression of the pro-apoptotic Bax protein. In conclusion, thymoquinone from N. sativa was more potent than cisplatin in elimination of SiHa cells via apoptosis with down-regulation of Bcl-2 protein.     

Effects of ginsenoside compound K combined with cisplatin on the proliferation,apoptosis and epithelial mesenchymal transition in MCF-7 cells of human breast cancer

Context: Breast cancer seriously harms the health of women and there are currently few therapeutic options for patients with breast cancer.

Objective: Effects of ginsenoside compound K (CK) in combination with cisplatin (DDP) on the proliferation, apoptosis, and epithelial mesenchymal transition (EMT) of MCF-7 cells were studied.

Materials and methods: MCF-7 cells were divided into CK (50?μmol/L) group, DDP (10?mg/L) group, CK (50?μmol/L)?+DDP (10?mg/L) group, and control (CON) group. The cells in the CON group were not treated with any drugs. Proliferation, apoptosis, expression of E-cadherin, N-cadherin, vimentin, protein kinase B (Akt), phosphorylated Akt (p-Akt), and level of fibronectin (FN) in MCF-7 cells were detected by methyl thiazolyl tetrazolium (MTT), flow cytometry, western blotting, and enzyme-linked immuno sorbent assay (ELISA), respectively.

Results: The proliferation inhibition rates in CK, DDP, and CK?+?DDP groups at 48?h were 19.18?±?2.25, 21.34?±?2.84, and 43.37?±?5.62, respectively. The apoptosis rates were 2.85?±?0.56, 13.37?±?2.28, 20.04?±?2.92, and 30.78?±?4.64 at 24?h and 3.14?±?0.72, 20.36?±?3.28, 27.58?±?4.09, and 41.62?±?5.83 at 48?h in CON, CK, DDP, and CK?+?DDP groups, respectively. CK or DDP alone and their combination all could reduce the levels of N-cadherin, vimentin, p-Akt/Akt, and FN and elevate level of E-cadherin.

Discussion and conclusion: Both CK and DDP can inhibit the proliferation, EMT, and induce the apoptosis in MCF-7 cells, which may be related to the PI3K/Akt pathway. In addition, the combination of CK with DDP can produce a better effect.     

Anticancer activity of newly synthesized 1,1-disubstituted cyclohexane-1-carboxamides: in vitro caspases mediated apoptosis activators in human cancer cell lines and their molecular modeling

Novel 1,1-disubstituted cyclohexane-1-carboxamides 6a-h , 7a-e , and 8a-b were designed and synthesized as apoptotic inducers. Cytotoxicity test revealed that some compounds have strong to moderate effect, while others displayed weak action against different cancer cell lines including, MCF-7, HepG2, A549, and HTC-116. A549 carcinoma cell line exhibited higher sensitivity toward all synthesized candidates especially compounds 6a and 8a which offered the lowest IC₅₀ values 3.03 and 5.21 μM, respectively, relative to the positive control doxorubicin with IC₅₀ value of 3.01 μM. Compared to doxorubicin treatment, compounds 6a and 8a induced caspases-3, -8, and -9 activities and G2/M growth arrest in A549 carcinoma cell line. The expression levels of p53 (tumor suppressor protein that in humans is encoded by the TP53 gene), Bax (apoptosis regulator protein in humans that is encoded by bax gene), and the Bax/Bcl-2 ratio were all higher than those in doxorubicin-treated cells (Bcl-2, B-cell lymphoma 2, encoded in humans by the Bcl-2 gene). Additionally, compounds 6a and 8a appeared to exhibit higher selectivity against MCF-10 human breast normal cell line. The synthesized congeners could be considered as potent apoptotic inducers interfering with extrinsic and intrinsic apoptotic pathways. Moreover, compound 6a was able to form complex with zinc ions as indicated by UV spectrophotometry which revealed its ability for being caspase activator. Molecular docking studies expected the interactions and binding modes of the synthesized inhibitors in the caspase-3 active site.     

Inhibitory effects of polyphenol-enriched extract from Ziyang tea against human breast cancer MCF-7 cells through reactive oxygen species-dependent mitochondria molecular mechanism

A polyphenol-enriched extract from selenium-enriched Ziyang green tea (ZTP) was selected to evaluate its antitumor effects against human breast cancer MCF-7 cells. In ZTP, (−)-epigallocatechin gallate (28.2%) was identified as the major catechin, followed by (−)-epigallocatechin (5.7%) and (−)-epicatechin gallate (12.6%). ZTP was shown to inhibit MCF-7 cell proliferation (half maximal inhibitory concentration, IC₅₀ = 172.2 μg/mL) by blocking cell-cycle progression at the G0/G1 phase and inducing apoptotic death. Western blotting assay indicated that ZTP induced cell-cycle arrest by upregulation of p53 and reduced the expression of CDK2 in MCF-7 cells. ZTP-caused cell apoptosis was associated with an increase in Bax/Bcl-2 ratio, and activation of caspase-3 and -9. MCF-7 cells treated with ZTP also showed an overproduction of reactive oxygen species, suggesting that reactive oxygen species played an important role in the induction of apoptosis in MCF-7 cells. This is the first report showing that ZTP is a potential novel dietary agent for cancer chemoprevention or chemotherapy.     

Improvement of cytotoxic and apoptogenic properties of crocin in cancer cell lines by its nanoliposomal form

Objective: Saffron Crocus sativus L. (Iridaceae) is known for anticancer properties. However, limited effort has been made to correlate these effects to the active ingredients of saffron. In the present study, cytotoxic effects of crocin, the major coloring compound in saffron, and its nanoliposomal form for better cellular delivery are investigated.

Methods: HeLa and MCF-7 cells were cultured and exposed to crocin (1, 2, and 4?mM) and liposomal crocin (0.5 and 1?mM). The 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to assess cytotoxicity. Apoptotic cells were determined using propidium iodide (PI) staining of DNA fragmentation by flow cytometry.

Results: MTT assay revealed a remarkable and concentration-dependent cytotoxic effect of crocin on HeLa and MCF-7 cells in comparison with non-malignant cell line (L929). Crocin liposomal forms (IC₅₀ values after 48 h: 0.61, 0.64, and 1.2?mM) showed enhanced cytotoxic effect compared with the crocin (IC₅₀ after 48 h: 1.603?mM) in HeLa cells. Crocin and its liposomal form induced a sub-G1 peak in flow cytometry histogram of treated cells indicating apoptosis is involved in this toxicity. Liposomal encapsulation enhances apoptogenic effects of crocin on cancerous cells.

Conclusion: It might be concluded that crocin and its liposomes could cause cell death in HeLa and MCF-7 cells, in which liposomal encapsulation improved cytotoxic effects. They could be also considered as a promising chemotherapeutic agent in cancer treatment in future.     

Leonurine hydrochloride induces apoptosis of H292 lung cancer cell by a mitochondria-dependent pathway

Abstract

Context: Leonurine hydrochloride (LH), a major alkaloid compound extracted from Leonurus japonicas Houtt. (Labiatae), is considered to have antitumor roles.

Objective: This study investigated its effects on human non-small cell lung cancer (NSCLC) H292 cells and illustrated the possible mechanism involved.

Materials and methods: After treatment with different concentrations of LH (0, 10, 25, and 50?μmol/L) for 6, 12, 24, 48, and 72?h, the cell viability was assessed by the MTT assay. After exposed to different doses of LH for 24?h, cell-cycle distribution, cell apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) were monitored by flow cytometry. RT-PCR and western blot were used to detect the expression of apoptosis-related genes.

Results: LH significantly inhibited the proliferation of H292 cells in a time- and dose-dependent manner, and induced G0/G1 cell-cycle arrest. Coincidentally, LH treatment at a dose of 10, 25, and 50?μmol/L for 24?h increased apoptotic ratio from 4.9?±?0.43% to 11.5?±?1.12%, 19.3?±?1.16%, and 61.3?±?6.69%, respectively. The inhibition effect of LH on H292 cells was associated with the loss of MMP and the generation of ROS. The phosphorylation level of p38 was increased and Akt phosphorylation was reduced by LH treatment. Furthermore, LH treatment increased the expression levels of caspase-3, caspase-9 and Bax/Bcl-2.

Conclusions: LH inhibits the proliferation and induces the apoptosis of H292 cells in a mitochondria-dependent pathway, and the specific mechanism need to be further explored.     

Genistein induces activation of the mitochondrial apoptosis pathway by inhibiting phosphorylation of Akt in colorectal cancer cells

Context: Genistein inhibits the proliferation and induces apoptosis of colorectal cancer cells; however, the underling molecular mechanisms remain to be determined.

Aim: The aim of this study was to investigate whether genistein reduces cell viability by suppressing the phosphorylation of AKT and activating the mitochondrial apoptosis pathway in colorectal cancer cells.

Materials and methods: The anti-proliferative effects of genistein (0, 25, 50, and 100?μM) on HCT-116 and LoVo cells were assessed using MTT assay. Genistein-induced apoptosis was measured by Hoechst 33258 staining and flow cytometry. The mRNA level of Bax was detected by real-time PCR. The protein levels of Bax, total Akt, and phosphorylated Akt were assessed by western blot.

Results: The IC₅₀ values of genistein were 690, 135, and 61?μM in HCT-116 cells and 204, 135, and 93?μM in LoVo cells after treatment for 24, 48, and 72?h, respectively. After treatment with different concentrations of genistein (0, 25, 50, and 100?μM) for 48?h, the early apoptotic cells in HCT-116 increased from 1.99%?±?0.55% to 6.78%?±?2.12%, 23.16%?±?3.87%, and 36.99%?±?3.76%, respectively. The same concentrations of genistein increased the early apoptotic cells in LoVo from 2.56%?±?1.42% to 3.21%?±?1.52%, 18.22%?±?3.56%, and 23.56%?±?3.02%, respectively. Moreover, genistein increased the mRNA and protein levels of Bax, while it inhibited the phosphorylation of Akt in HCT-116 cells.

Conclusion: Genistein inhibited cell proliferation and induced apoptosis of colorectal cancer cells. Genistein induced the mitochondrial pathway of apoptosis in HCT-116 cells by inhibiting phosphorylation of Akt.