Tebufenozide induces G1/S cell cycle arrest and apoptosis in human cells

Tebufenozide is a non-steroidal insect growth regulator and is extensively used to control pests, although it is considered to be safe for mammals and environmentally friendly. However, previous studies have found that tebufenozide is cytotoxic to man, although the exact mechanism remains elusive. This study will investigate the apoptotic molecular mechanisms which result from tebufenozide-induced DNA damage in HeLa cells. Our results demonstrate that tebufenozide could trigger arrest in G1/S phase related to a downregulation of cyclin E and cyclin-dependent kinase (CDK) 2 protein. In addition, Western blotting showed apoptosis was associated with the upregulation of p53, Bax and cleaved-PARP, as well as downregulation of Bcl-2 and PARP. Tebufenozide also regulated changes in mitochondrial permeability and reduced mitochondrial number and intracellular ATP production. Briefly, these results suggest that tebufenozide- induces cell cycle arrest and apoptosis through activating p53 protein in a Bax- and Bcl-2-triggered mitochondrial pathway. This work provides some scientific context for the safe use of tebufenozide in agriculture.     

Luteolin induced G2 phase cell cycle arrest and apoptosis on non-small cell lung cancer cells

In this study, we investigated the underlying molecular mechanism for the potent cell cycle inhibition and pro-apoptotic effect of luteolin (2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-chromenone) on human non-small-cell lung carcinoma cell line A549. MTT assay showed that luteolin had obvious cytotoxicity on A549 with IC₅₀ of 40.2 μM at 48 h. Pro-apoptotic effect of luteolin on A549 cells was demonstrated by Hoechst 33258 staining assay and annexin V-FITC/PI double staining analysis. A great quantity of apoptotic cells and increasing G2 phase cells were observed by flow cytometry. Western blotting assay revealed that luteolin activated JNK, increased Bax, promoted procaspase-9 cleavage and activated caspase-3 at last. Assay using TNFα, an active agent of NF-κB, showed that pretreatment of A549 cells with luteolin could inhibit TNFα induced trans-nuclear of NF-κB. In summary, luteolin displayed a significant cytotoxic effect through cell cycle arrest and apoptosis induction in A549 cells. Pro-apoptotic effect was implemented via activating JNK and inhibiting translocation of NF-κB (p65). These results suggested that luteolin might have therapeutic potential against NSCLC.     

冬凌草甲素诱导胃癌BGC-823细胞凋亡及G2／M细胞周期阻滞作用研究

目的研究冬凌草甲素体外诱导胃癌BGC-823细胞凋亡和细胞周期阻滞的作用，阐明其作用机理，为临床应用提供科学依据。方法用MTT方法测定冬凌草甲素体外抑制BGC-823细胞生长的作用。用共聚焦荧光显微镜和流式细胞仪分别观察诱导凋亡的情况。线粒体膜电位和细胞内钙离子浓度分别用荧光探针标记后流式细胞仪测定。凋亡和细胞周期相关蛋白的表达用Westem blotting进行测定。结果冬凌草甲素对BGC-823细胞的半数生长抑制浓度IC50值为22．21μmol.L^-1，并诱导细胞凋亡，呈现浓度依赖性。此外，能够降低线粒体膜电位，升高细胞内钙离子浓度，激活caspase-3前体。同时，冬凌草甲素能够使得BGC-823细胞阻滞在细胞周期的G2／M期，伴随有cyclin A蛋白的表达下降。在发生凋亡和细胞阻滞之前，观察到p53蛋白的表达增加。结论冬凌草甲素能够诱导BGC-823细胞产生凋亡，并使细胞周期阻滞在G2／M期。其凋亡机理与caspase-3的激活，p53蛋白表达上调及cyclin A表达下调相关。     

Induction of apoptosis and G2/M cell cycle arrest by Gleditsioside E from Gleditsia sinensis in HL-60 cells

Gleditsioside E, a triterpene saponin isolated from Gleditsia sinensis, showed significant cytotoxicity against Bel-7402, BGC-823, HeLa, HL-60 and MCF-7 cell lines. The results of flow cytometry with annexin V-FITC/PI double staining proved that gleditsioside E mainly induced early apoptosis in HL-60 cells. Gleditsioside E treatment resulted in a prominent increase of the G 2 /M population in HL-60 cells, and an accumulation of the sub-G 1 (hypoploid) peak was observed.     

土贝母苷甲诱导HeLa细胞周期阻滞和凋亡

目的 :研究土贝母苷甲 (下称苷甲 )抗肿瘤作用的机制 ,探索它对细胞周期和细胞凋亡的影响。方法 :采用MTT法检测苷甲对细胞生长的抑制作用 ;采用流式细胞术 ,光学、荧光和电子显微镜 ,以及DNA琼脂糖凝胶电泳检查和分析苷甲对细胞周期和细胞凋亡的影响 ;采用蛋白免疫印迹法检测凋亡相关基因bcl 2和bax表达的变化。结果 :苷甲对HeLa细胞的生长有强抑制作用 ,其 2 4、4 8和 72h的IC50 值分别为 35 .7,2 3.6 ,17.4 μmol·L-1。在苷甲的作用下 ,细胞周期阻滞在G2 M期 ,细胞在形态学和生物化学上都出现了细胞凋亡的典型证据。蛋白免疫印迹结果揭示bcl 2下调 ,bax过表达。结论 :苷甲诱导的细胞周期阻滞和凋亡在苷甲的抗肿瘤效果中可能起着重要作用 ,而苷甲诱导的细胞凋亡与bcl 2的下调及bax的过表达密切相关。     

Induction of germline cell cycle arrest and apoptosis by sodium arsenite in Caenorhabditis elegans

The nematode Caenorhabditis elegans has been shown to be a model organism in studying aquatic toxicity. Although epidemiological studies have shown that arsenic is teratogenic and carcinogenic to humans, the lethality assay indicated that C. elegans is less sensitive to inorganic arsenic than any other organisms that have been tested thus far. In the present study, we used the more malleable germline of C. elegans as an in vivo system to investigate the genotoxic effects of arsenite. After animals were exposed to sodium arsenite at concentrations ranging from 1 microM to 0.5 mM, mitotic germ cells and germline apoptosis were scored after DAPI staining and acridine orange vital staining, respectively. DMSO rescue experiments were performed by exposing C. elegans to 0.01 mM arsenite in the presence of DMSO (0.1%) for 24 h, and reactive oxygen species (ROS) were semiquantified by CM-H(2)DCFDA vital staining. The results indicated that arsenic exposure reduced the brood size of C. elegans and caused mitotic cell cycle arrest and germline apoptosis, which, to some extent, exhibited a concentration- and time-dependent manner. The addition of 0.1% DMSO completely rescued arsenic-induced cell cycle arrest and partially suppressed germline apoptosis. Furthermore, treatment of animals with arsenite at a dose of 0.01 mM significantly increased ROS production in the intestine, which could be reduced by DMSO treatment. The present study also indicated that C. elegans might be used as an in vivo model system to study the mechanisms of arsenic-induced genotoxic effects.     

Artesunate induces G0/G1 cell cycle arrest and iron-mediated mitochondrial apoptosis in A431 human epidermoid carcinoma cells

The anticancer effects of artesunate (ART) have been well documented. However, its potential against skin cancer has not been explored yet. Herein we reported that 60 μmol/l ART effectively inhibited A431 (human epidermoid carcinoma cells) growth but not that of HaCaT (normal human keratinocyte cells). Our results revealed that ART induced cell cycle arrest at G0/G1 phase through the downregulation of cyclin A1, cyclin B, cyclin D1, Cdk2, Cdk4, and Cdk6. This correlated with the upregulation of p21 and p27. The 5-bromodeoxyuridine incorporation assay also indicated that ART treatment reduced DNA synthesis in a time-dependent manner. Furthermore, ART induced mitochondrial apoptosis, as evidenced by annexin V/propidium iodide staining and western blot analysis. Interestingly, ART-induced apoptosis diminished under iron-deficient conditions but intensified under iron-overload conditions. Taken together, these findings demonstrated the potential of ART in treating skin cancer through the induction of G0/G1 cell cycle arrest and iron-mediated mitochondrial apoptosis and supported further investigations in other test systems.     

Induction of cell cycle arrest and apoptosis in human non-small cell lung cancer A549 cells by casuarinin from the bark of Terminalia arjuna Linn

Casuarinin, a hydrolyzable tannin isolated from the bark of Terminalia arjuna Linn. (Combretaceae), inhibits human non-small cell lung cancer A549 cells by blocking cell cycle progression in the G0/G1 phase and inducing apoptosis. Enzyme-linked immunosorbent assay showed that the G0/G1 phase arrest is due to p53-dependent induction of p21/WAF1. An enhancement in Fas/APO-1 and the two forms of Fas ligand (FasL), membrane-bound FasL and soluble FasL, might be responsible for the apoptotic effect induced by casuarinin. Our study reports here for the first time that the induction of p53 and the activity of the Fas/FasL apoptotic system may participate in the antiproliferative activity of casuarinin in A549 cells.     

Carboxyamido-triazole inhibits proliferation of human breast cancer cells via G(2)/M cell cycle arrest and apoptosis

Carboxyamido-triazole (CAI), a voltage-independent calcium channel inhibitor, has been shown to be able to induce growth inhibition and apoptosis in cancer cells. In the present study, we demonstrate that CAI significantly inhibits proliferation of cultured MCF-7 human breast cancer cells in a dose-dependent manner with an IC(50) of approximately 26 microM. Reduced proliferation of MCF-7 cells in the presence of CAI correlated with accumulation of cells in G(2)/M phase and induction of apoptosis. A treatment of MCF-7 cells with 30 microM CAI caused a time-dependent decrease in the levels of proteins that regulate G(2)/M progression, including Cdk1, Cyclin B1, and Cdc25C. A simultaneous increase in the expression of p21 protein was observed. We also demonstrated a concurrent decrease of the mitochondrial membrane potential (DeltaPsi(m)), and down-regulation of anti-apoptotic protein Bcl-2. In conclusion, it seems reasonable to hypothesize that the antitumor effect of CAI in MCF-7 cells is based on G(2)/M cell cycle arrest and inducing apoptosis.     

鱼藤素诱导肺癌细胞凋亡和细胞周期阻滞的分子机制

目的探究鱼藤素是否能够阻滞细胞周期和细胞迁移,抑制非小细胞肺癌细胞的增殖。方法鱼藤素(1. 5625、3. 125、6. 25、12. 5、25、50μmol·L~(-1))处理H1299细胞不同时间后,CCK-8法检测细胞存活率,划痕实验测定划痕宽度及愈合率;鱼藤素(1. 5、3、6μmol·L~(-1))处理24 h,PI单染测定细胞周期,Annexin V-FITC/PI双染检测凋亡率,q PCR检测药物处理后的H1299细胞中CDK4、CDK6和CCND1的基因表达情况。结果鱼藤素能够降低H1299细胞的存活率,作用24、48、72 h的IC50值分别为(5. 47±0. 97)、(4. 01±0. 45)、(2. 86±0. 19)μmol·L~(-1),并抑制细胞的迁移与愈合能力。PI单染流式细胞术检测到其能阻滞细胞周期,使细胞阻滞在G0/G1期,流式双染实验测得其可诱导细胞的凋亡,q PCR发现鱼藤素可下调CDK4、CDK6和CCND1的基因表达。结论鱼藤素可抑制H1299细胞的增殖,抑制细胞的运动迁移能力,阻滞细胞周期,诱导细胞凋亡,且鱼藤素可通过下调细胞周期调控系统中的CDK4、CDK6、CCND1基因表达来调控细胞周期,达到抗肿瘤作用。     

Induction of G1 cell cycle arrest and cyclin D1 down-regulation in response to pericarp extract of Baneh in human breast cancer T47D cells

Background and the purpose of the study

Natural products from plants have an important role in the development and production of new drugs mainly for cancer therapy. More recently, we have shown that the pericarp methanolic extract of Pistacia atlantica sub kurdica (with local name of Baneh) as a rich source of active biological components with high antioxidant and radical scavenging activities, has ability to cease proliferation and induce apoptosis in T47D human breast cancer cells. The present study aimed to clarify whether Baneh extract able to alter cell cycle progression of T47D cells or not.

Methods

In order to study the possible effect of Baneh extract on cell cycle of T47D cells, we evaluated cell cycle distribution and its regulatory proteins by flow cytometry and western blot analysis respectively.

Results

Baneh extract induced G₀/G₁ cell cycle arrest in conjunction with a marked decrease in expression of cyclin D1 and cdk4 that was strongly dependent on time of exposure. In parallel, Dox-treated T47D cells in early time points were accumulated on S phase, but after 48 h cell cycle progression was inhibited on G₂/M. Dox promoted striking accumulation of cyclin B1 rapidly and enhanced cyclin A abundance.

Conclusion

Taken together, our results establish that the antitumor activity of the pericarp extract of Baneh partly is mediated via cell cycle arrest and downregulation of cyclin D1 and cdk4 expression. These findings warrant further evaluation regarding the mechanism(s) of action of this promising anticancer agent.     

Induction of apoptosis and cell cycle arrest by pericarp polyphenol-rich extract of Baneh in human colon carcinoma HT29 cells

Plants as important source of natural active components with anticancer effects commonly are different in structure and biological properties. The pericarp of Pistacia atlantica sub kurdica with local name of Baneh, a rich source of active phytochemicals, contains noticeable amounts of polyphenolic compounds, flavonoids and anthocyanins. Therefore, the antiproliferative, apoptosis induction and cell cycle alterations of Baneh were evaluated in human colon carcinoma HT29 cells. The Baneh extract (0.7 mg/ml) resulted in 50% growth inhibition similar to 500 nM of Doxorubicin (Dox) in HT29 cells after 72 h. The down-regulation of cyclin A protein by Baneh extract induced S phase delay in cell cycle progression of HT29 cells. Unlike the Baneh extract, Dox showed G2/M accumulation of HT29 cells which was associated with an increase in cyclin A and cyclin B1 protein expression. Furthermore, the induction of apoptosis following Baneh extract and Dox treatment in HT29 cells was confirmed by DNA fragmentation and translocation of phosphatidylserine. The morphological characteristics of apoptosis were also observed in HT29 cells exposed to the Baneh extract and Dox. These results suggest that due to the existence of bioactive components, methanolic extract of the Baneh has significant cytotoxic effects against human colon carcinoma HT29 cells.     

Induction of apoptosis and cell-cycle arrest in human colon cancer cells by meclizine.

Meclizine (MEC), a histamine H1 antagonist, is used for the treatment of motion sickness and vertigo. In this study, we demonstrate that MEC dose-dependently induced apoptosis in human colon cancer cell lines (COLO 205 and HT 29 cells). Results of a DNA ladder assay revealed that DNA ladders appeared with MEC treatment in COLO 205 cells at dosage of >50 microM. In addition, the total cell number decreased dose-dependently after treatment with MEC in COLO 205 and HT 29 cells. Using flow cytometry, the percentage of COLO 205 cells arrested at G0/G1 phase increased dose-dependently. Analysis of changes in cell-cycle arrest-associated proteins with Western blotting showed that p53 and p21 were upregulated after treatment with MEC. The kinase activities of cyclin-dependent kinase 2 (CDK2) and CDK4 were suppressed in MEC-treated cells. As for apoptosis, MEC may induce upregulation of p53 and downregulation of Bcl-2, thus causing the release of cytochrome C from mitochondria and the translocation of apoptosis-inducing factor (AIF) to the nucleus. This resulted in the activation of caspase 3, 8, and 9. Our results provide the molecular basis of MEC-induced apoptosis and cell-cycle arrest in human colon cancer cells.     

Licochalcone B inhibits growth of bladder cancer cells by arresting cell cycle progression and inducing apoptosis

To examine the mechanisms by which licochalcone B (LCB) inhibits the proliferation of human malignant bladder cancer cell lines (T24 and EJ) in vitro and antitumor activity in vivo in MB49 (murine bladder cancer cell line) tumor model. Exposure of T24 or EJ cells to LCB significantly inhibited cell lines proliferation in a concentration-dependent and time-dependent manner, and resulted in S phase arrest in T24 or EJ cells, respectively. LCB treatment decreased the expression of cyclin A, cyclin-dependent kinase (CDK1 and CDK2) mRNA, cell division cycle 25 (Cdc25A and Cdc25B) protein. In addition, LCB treatment down-regulated Bcl-2 and survivin expression, enhanced Bax expression, activated caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) protein. Consistently, the tumorigenicity of LCB-treated MB49 cells was limited significantly by using the colony formation assay in vitro and the MB49 tumor model performed in C57BL/6 mice in vivo. These findings provide support for the use of LCB in chemoprevention and bladder cancer therapy.     

紫草素促进食管癌细胞凋亡及细胞周期阻滞的作用机制研究

目的研究紫草素促进食管癌细胞凋亡及细胞周期阻滞的作用及机制。方法 2019年 1月至 2020年 6月期间开展细胞实验,培养食管癌 Eca109细胞,分为不含药物杜氏改良 Eagle培养基( DMEM)处理的对照组,含不同剂量紫草素 DMEM处理的紫草素组,含 2.0 μmol/L紫草素和 10 μg/L胰岛素样生长因子 -1(IGF-1)DMEM处理的 2.0 μmol/L紫草素 +10μg/L IGF-1组。检测细胞凋亡率、细胞周期及凋亡基因活化的胱天蛋白酶 -3(cleaved caspase-3)、细胞周期蛋白 D1(cyclin D1)、磷酸化磷酸肌醇 3激酶( PI3K)、蛋白激酶 B(AKT)的表达量。结果 0.5 μmol/L紫草素组、 1.0 μmol/L紫草素组、 2.0 μmol/L紫草素组的细胞凋亡率、细胞周期 G1期比例、 cleaved caspase-3的表达量［ 0.5 μmol/L紫草素组( 0.64±0.14)、 1.0 μmol/L紫草素组( 0.81±0.19)、2.0 μmol/L紫草素组( 1.02±0.24)］高于对照组 0.41±0.07,细胞周期 S期、 G2期比例及 cyclin D1［0.5 μmol/L紫草素组( 0.80±0.16)、 1.0 μmol/L紫草素组( 0.68±0.13)、 2.0 μmol/L紫草素组( 0.45±0.09)］、 p-PI3K、p-AKT表达量低于对照组［ cyclin D1表达量(0.91±0.18)］(P<0.05); 2.0 μmol/L紫草素 +10 μg/L IGF-1组的细胞凋亡率、细胞周期 G1期比例、 cleaved caspase-3的表达量低于 2.0 μmol/L紫草素组,细胞周期 G2期比例及 cyclin D1、p-PI3K、p-AKT表达量高于 2.0 μmol/L紫草素组( P<0.05)。结论紫草素具有促进食管癌细胞凋亡及细胞周期阻滞的作用,该作用与抑制 PI3K/AKT通路激活有关。