Initiation of apoptosis,cell cycle arrest and autophagy of esophageal cancer cells by dihydroartemisinin

Dihydroartemisinin (DHA) has recently been shown anti-tumor activity in various cancer cells. However, its effect on esophageal cancer remains unclear. In this study, for the first time, we demonstrated that DHA reduced viability of esophageal cancer cells in a dose-dependent manner. The mechanism was at least partially due to DHA induced apoptosis by upregulating the expression of Bax, downregulating Bcl-2, Bcl-xL and Procaspase-3, and increasing caspase-9 activation, induced cell cycle arrest by downregulating cyclin E, CDK2 and CDK4. Furthermore, we firstly found that DHA induced autophagy in cancer cells. We concluded DHA might be a novel agent against esophageal cancer.     

Sonoporation induces apoptosis and cell cycle arrest in human promyelocytic leukemia cells

Despite being a transient biophysical phenomenon, sonoporation is known to disturb the homeostasis of living cells. This work presents new evidence on how sonoporation may lead to antiproliferation effects including cell-cycle arrest and apoptosis through disrupting various cell signaling pathways. Our findings were obtained from sonoporation experiments conducted on HL-60 human promyelocytic leukemia cells (with 1% v/v microbubbles; 1 MHz ultrasound; 0.3 or 0.5MPa peak negative pressure; 10% duty cycle; 1 kHz pulse repetition frequency; 1 min exposure period). Membrane resealing in these sonoporated cells was first verified using scanning electron microscopy. Time-lapse flow cytometry analysis of cellular deoxyribonucleic acid (DNA) contents was then performed at four post-sonoporation time points (4 h, 8 h, 12 h and 24 h). Results indicate that an increasing trend in the apoptotic cell population can be observed for at least 12 h after sonoporation, whilst viable sonoporated cells are found to temporarily accumulate in the G₂/M (gap-2/mitosis) phase of the cell cycle. Further analysis using western blotting reveals that sonoporation-induced apoptosis involves cleavage of poly adenosine diphosphate ribose polymerase (PARP) proteins: a pro-apoptotic hallmark related to loss of DNA repair functionality. Also, mitochondrial signaling seems to have taken part in triggering this cellular event as the expression of two complementary regulators for mitochondrial release of pro-apoptotic molecules, Bcl-2 (B-cell lymphoma 2) and Bax (Bcl-2-associated X), are seen to be imbalanced in sonoporated cells. Furthermore, sonoporation is found to induce cell-cycle arrest through perturbing the expression of various cyclin and Cdk (cyclin-dependent kinase) checkpoint proteins that play an enabling role in cell-cycle progression. These bioeffects should be taken into account when using sonoporation for therapeutic purposes.     

Citral inhibits cell proliferation and induces apoptosis and cell cycle arrest in MCF-7 cells

Many natural components of plants extract are studied for their beneficial effects on health and particularly on carcinogenesis chemoprevention. In this study, we investigated the effect of citral (3,7-dimethyl-2,6-octadienal), a key component of essential oils extracted from several herbal plants, on the proliferation rate, cell cycle distribution, and apoptosis of the human breast cancer cell line MCF-7. The effects of this compound were also tested on cyclo-oxygenase activity. Citral treatment caused inhibition of MCF-7 cell growth (IC₅₀-48 h: 18  ×  10⁻⁵  m ), with a cycle arrest in G₂/M phase and apoptosis induction. Moreover, we observed a decrease in prostaglandin E₂ synthesis 48 h after citral treatment. These findings suggest that citral has a potential chemopreventive effect.     

Matrix metalloproteinase inhibitors cause cell cycle arrest and apoptosis in glomerular mesangial cells

Inflammation is characterized by an excess of cell proliferation often leading to fibrosis and sclerosis with subsequent loss of organ function. We hypothesized that these features may be ameliorated by induction of cell cycle arrest and apoptosis as result of therapy with matrix metalloproteinase (MMP) inhibitors. In our study, mesangial cells and experimental mesangial proliferative glomerulonephritis provided the model of inflammation. First, we investigated the effect of the MMP inhibitor BB-1101 in anti-Thy1.1 nephritis. The numbers of apoptotic glomerular cells in nephritic rats increased about 4 and 6 times as a result of BB-1101 therapy, observed 11 and 14 days after induction of disease, respectively. Subsequently, rat mesangial cells were exposed to an MMP inhibitor in vitro. Fluorescence-activated cell sorter analyses of cells exposed to RO111-3456 demonstrated a dose-dependent cell cycle arrest in the G(0)/G(1) phase associated with increased expression of statin. The cell cycle arrest was followed by apoptosis as investigated by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) biotin nick-end labeling (TUNEL) and acridine orange/ethidium bromide stainings, as well as by annexin V binding. The induction of p53, p21, and bax, but not the Fas/FasL pathway appeared to play an important pathogenetic role. In summary, MMP inhibitors induce cell cycle arrest followed by apoptosis in mesangial cells. These features help to explain the anti-inflammatory effects of these compounds, such as reduction of mesangial cell proliferation and attenuation of extracellular matrix accumulation. In conclusion, induction of cell cycle arrest with subsequent apoptosis may offer new perspectives in the therapy of inflammation even beyond kidney diseases.     

Synthetic phosphoethanolamine induces cell cycle arrest and apoptosis in human breast cancer MCF-7 cells through the mitochondrial pathway

Phosphoethanolamine (Pho-s) is a compound involved in phospholipid turnover, acting as a substrate for many phospholipids of the cell membranes. In a recent study, we showed that Pho-s has antitumor effect in the several tumor cells. In this study we evaluated the antitumor activity of synthetic Pho-s on MCF-7 breast cancer cells. Here we demonstrate that Pho-s is cytotoxic to MCF-7 cells in a dose-dependent manner, while it is cytotoxic to MCF10 only at higher concentrations. In addition, Pho-s induces a disruption in mitochondrial membrane potential (Δψm). Furthermore, Pho-s induces mitochondria aggregates in the cytoplasm and DNA fragmentation of MCF-7 cells visualized by confocal microscopy. In agreement with the reduction on Δψm, we showed that Pho-s induces apoptosis followed by an increase in cytochrome c expression and capase-3-like activity in MCF-7 cells. Our results demonstrate that Pho-s induces a cell cycle arrest in the G1 phase through an inhibition of cyclin D1 and stimulates p53. An additional highlight of this study is the finding that Pho-s inhibits Bcl-2, inducing apoptosis through the mitochondrial pathway. Taken together, these results show that Pho-s is a promising compound in the fight against cancer.     

The dietary isothiocyanate sulforaphane targets pathways of apoptosis, cell cycle arrest, and oxidative stress in human pancreatic cancer cells and inhibits tumor growth in severe combined immunodeficient mice

Anticancer effects of the dietary isothiocyanate sulforaphane were investigated in the human pancreatic cancer cell lines MIA PaCa-2 and PANC-1. Sulforaphane-treated cells accumulated in metaphase as determined by flow cytometry [4C DNA content, cyclin A(-), cyclin B1(+), and phospho-histone H3 (Ser(10))(+)]. In addition, treated cells showed nuclear apoptotic morphology that coincided with an activation of caspase-8, loss of mitochondrial membrane potential, and loss of plasma membrane integrity. The initial detection of caspase-3 cleavage occurring in G(2)-M arrest was independent of a change in phospho-cdc2 (Tyr(15)) protein; consequently, sulforaphane treatment combined with UCN-01 had no significant impact on cellular toxicity. Incubations at higher sulforaphane doses (>10 micromol/L) resulted in cleavage of caspase-3 in the G(1) subpopulation, suggesting that the induction of apoptosis and the sulforaphane-induced mitosis delay at the lower dose are independently regulated. Cellular toxicity in MIA PaCa-2, and to a greater extent in PANC-1, was positively correlated with a decrease in cellular glutathione levels, whereas sustained increases in glutathione observed in MIA PaCa-2 cells or the simultaneous incubation with N-acetyl-L-cysteine in PANC-1 cells were associated with resistance to sulforaphane-induced apoptosis. Daily sulforaphane i.p. injections (375 micromol/kg/d for 3 weeks) in severe combined immunodeficient mice with PANC-1 s.c. tumors resulted in a decrease of mean tumor volume by 40% compared with vehicle-treated controls. Our findings suggest that, in addition to the known effects on cancer prevention, sulforaphane may have activity in established pancreatic cancer.     

Proteasome-mediated degradation of cell division cycle 25C and cyclin-dependent kinase 1 in phenethyl isothiocyanate-induced G2-M-phase cell cycle arrest in PC-3 human prostate cancer cells

Phenethyl isothiocyanate (PEITC), a constituent of many cruciferous vegetables, offers significant protection against cancer in animals induced by a variety of carcinogens. The present study demonstrates that PEITC suppresses proliferation of PC-3 cells in a dose-dependent manner by causing G(2)-M-phase cell cycle arrest and apoptosis. Interestingly, phenyl isothiocyanate (PITC), which is a structural analogue of PEITC but lacks the -CH(2) spacers that link the aromatic ring to the -N=C=S group, neither inhibited PC-3 cell viability nor caused cell cycle arrest or apoptosis. These results indicated that even a subtle change in isothiocyanate (ITC) structure could have a significant impact on its biological activity. The PEITC-induced cell cycle arrest was associated with a >80% reduction in the protein levels of cyclin-dependent kinase 1 (Cdk1) and cell division cycle 25C (Cdc25C; 24 h after treatment with 10 micro M PEITC), which led to an accumulation of Tyr(15) phosphorylated (inactive) Cdk1. On the other hand, PITC treatment neither reduced protein levels of Cdk1 or Cdc25C nor affected Cdk1 phosphorylation. The PEITC-induced decline in Cdk1 and Cdc25C protein levels and cell cycle arrest were significantly blocked on pretreatment of PC-3 cells with proteasome inhibitor lactacystin. A 24 h exposure of PC-3 cells to 10 micro M PEITC, but not PITC, resulted in about 56% and 44% decrease in the levels of antiapoptotic proteins Bcl-2 and Bcl-X(L), respectively. However, ectopic expression of Bcl-2 failed to alter sensitivity of PC-3 cells to growth inhibition or apoptosis induction by PEITC. Treatment of cells with PEITC, but not PITC, also resulted in cleavage of procaspase-3, procaspase-9, and procaspase-8. Moreover, the PEITC-induced apoptosis was significantly attenuated in the presence of general caspase inhibitor and specific inhibitors of caspase-8 and caspase-9. In conclusion, our data indicate that PEITC-induced cell cycle arrest in PC-3 cells is likely due to proteasome-mediated degradation of Cdc25C and Cdk1, and ectopic expression of Bcl-2 fails to confer resistance to PEITC-induced apoptosis. Furthermore, the results of the present study point toward involvement of both caspase-8- and caspase-9-mediated pathways in apoptosis induction by PEITC.     

Isostrychnopentamine,an indolomonoterpenic alkaloid from Strychnos usambarensis,induces cell cycle arrest and apoptosis in human colon cancer cells

Isostrychnopentamine (ISP) is an indolomonoterpenic alkaloid that is present in the leaves of Strychnos usambarensis, a well known African shrub or little tree. The roots contain quaternary alkaloids, which are used to make a curare-like arrow poison. However, tertiary alkaloids isolated from the same plant possess cytotoxic activities against mammalian cells and protozoa. The effect of ISP has been investigated on the growth and viability of HCT-116 colon cancer cells during their exponentially growing phase. ISP induced apoptotic cell death as shown by the translocation of phosphatidylserine from the inner layer to the outer layer of the plasma membrane, chromatin condensation, DNA fragmentation, and caspase-3 and -9 activation. ISP provoked also cell cycle arrest in the G(2)-M phase. We also showed that the expression of p53 was not modified in ISP-treated cells, but that p21 was induced in a p53-independent manner. Finally, we demonstrated that ISP did not affect the catalytic activity of human topoisomerases I and II. In conclusion, ISP, which promotes cell death by a p53-independent apoptotic pathway, could be an interesting lead for cancer chemotherapy.     

Tangeretin induces cell cycle arrest and apoptosis through upregulation of PTEN expression in glioma cells

Tangeretin (TANG), present in peel of citrus fruits, has been shown to various medicinal properties such as chemopreventive and neuroprotective. However, the chemopreventive effect of TANG on glioblastoma cells has not been examined. The present study was designed to explore the anticancer potential of TANG in glioblastoma cells and to investigate the related mechanism. Human glioblastoma U-87MG and LN-18 cells were treated with 45 μM concentration of TANG and cell growth was measured by MTT assay. The cell cycle distribution and cell death were measured by flow cytometry. The expression of cell cycle and apoptosis related genes were analyzed by quantitative RT-PCR and western blot. The cells treated with TANG were significantly increased cell growth suppression and cell death effects than vehicle treated cells. Further, TANG treatment increases G₂/M arrest and apoptosis by modulating PTEN and cell-cycle regulated genes such as cyclin-D and cdc-2 mRNA and protein expressions. Moreover, the ability of TANG to decrease cell growth and to induce cell death was compromised when PTEN was knockdown by siRNA. Taken together, the chemopreventive effect of TANG is associated with regulation of cell-cycle and apoptosis in glioblastoma, thereby attenuating glioblastoma cell growth. Hence, the present findings suggest that TANG may be a therapeutic agent for glioblastoma treatment.     

Berberine, a natural product, induces G1-phase cell cycle arrest and caspase-3-dependent apoptosis in human prostate carcinoma cells

Berberine, a naturally occurring isoquinoline alkaloid, has been shown to possess anti-inflammatory and antitumor properties in some in vitro systems. Here, we report that in vitro treatment of androgen-insensitive (DU145 and PC-3) and androgen-sensitive (LNCaP) prostate cancer cells with berberine inhibited cell proliferation and induced cell death in a dose-dependent (10-100 micromol/L) and time-dependent (24-72 hours) manner. Treatment of nonneoplastic human prostate epithelial cells (PWR-1E) with berberine under identical conditions did not significantly affect their viability. The berberine-induced inhibition of proliferation of DU145, PC-3, and LNCaP cells was associated with G1-phase arrest, which in DU145 cells was associated with inhibition of expression of cyclins D1, D2, and E and cyclin-dependent kinase (Cdk) 2, Cdk4, and Cdk6 proteins, increased expression of the Cdk inhibitory proteins (Cip1/p21 and Kip1/p27), and enhanced binding of Cdk inhibitors to Cdk. Berberine also significantly (P < 0.05-0.001) enhanced apoptosis of DU145 and LNCaP cells with induction of a higher ratio of Bax/Bcl-2 proteins, disruption of mitochondrial membrane potential, and activation of caspase-9, caspase-3, and poly(ADP-ribose) polymerase. Pretreatment with the pan-caspase inhibitor z-VAD-fmk partially, but significantly, blocked the berberine-induced apoptosis, as also confirmed by the comet assay analysis of DNA fragmentation, suggesting that berberine-induced apoptosis of human prostate cancer cells is mediated primarily through the caspase-dependent pathway. The effectiveness of berberine in checking the growth of androgen-insensitive, as well as androgen-sensitive, prostate cancer cells without affecting the growth of normal prostate epithelial cells indicates that it may be a promising candidate for prostate cancer therapy.     

RNAi targeting CXCR4 inhibits tumor growth through inducing cell cycle arrest and apoptosis

CXC chemokine receptor 4 (CXCR4) is involved in many human malignant tumors and plays an important role in tumor growth and metastasis. To explore the effects of CXCR4 expression on the malignant cells of oral squamous cell carcinoma (OSCC), Tca8113 and SCC-9 cell lines, as well as their xenograft models, of nude mice were used to detect cancer cell proliferation alteration. This study also examined the corresponding molecular mechanism after CXCR4 knockdown using a recombinant lentiviral vector expressing small interference RNA (siRNA) for CXCR4. RNA interference-mediated knockdown of CXCR4 in highly aggressive (Tca8113 and SCC-9) tumor cells significantly inhibited the proliferation of the two cell lines in vitro and in vivo. The expression levels of >1,500 genes involved in cell cycle, apoptosis, and multiple signaling pathways were also altered. These results provide new evidence of CXCR4 as a promising tumor gene therapeutic target.     

特拉唑嗪对前列腺癌细胞生长的影响

目的研究α1肾上腺素受体拮抗剂特拉唑嗪（高特灵）对激素非依赖性前列腺癌PC-3细胞生长的影响。方法不同浓度特拉唑嗪加入PC-3细胞。以MTr法检测细胞生长抑制率,并采用流式细胞术（FcM）检测细胞凋亡和细胞周期变化。结果15-50μmol／L特拉唑嗪作用24—96h,癌细胞生长部分受抑制;25、50μmol/L特拉唑嗪作用48h,部分细胞呈现凋亡特征性形态学改变。两项指标与对照组均有差异。结论特拉唑嗪通过诱导凋亡抑制激素非依赖性前列腺癌PC-3细胞生长,呈剂量依赖关系,临床上有望用于治疗激素非依赖性前列腺癌。     

Molecular analysis for prostate cancer

The molecular and biochemical mechanisms contributing to the development and progression of prostate carcinogenesis are still unknown. Recent technologies such as, real-time PCR, microarray, and laser capture microdissection, have accelerated the study of the molecular events involved in prostate cancer. The expression and function of numerous genes have been shown to be altered in prostate cancer. Such gene regulations are involved in cell cycle, signal transduction pathways, or gene expression. Analysis of the genes during prostate cancer progression has provided a better understanding of the basis of the disease. This review summarises current knowledge of the molecular analysis for prostate cancer.     

Molecular targets in cancer therapy

OBJECTIVES: To review selected pharmacologic agents that target key cellular processes along with their mechanisms of action and adverse events. Nursing implications including what patients and families need to know, administration issues, and management of common toxicities will be reviewed. DATA SOURCES: Research articles, clinical trials, abstracts, and book chapters. CONCLUSION: Knowledge of complex biology and biochemistry regulating normal and abnormal cellular function obtained over the past 30 years is starting to be used clinically for new therapies to treat cancer. By targeting what makes cancer unique, these therapies are able to spare more healthy or normal cells than the standard treatments, such as radiation and chemotherapy. Several molecular targeting agents are now in use and even more are under study as cancer treatments. IMPLICATIONS FOR NURSING PRACTICE: Oncology nurses must understand the principles underlying targeted treatments and their potential benefits to provide adequate patient education and care.     

Plumbagin induces ROS-mediated apoptosis and cell cycle arrest and inhibits EMT in human cervical carcinoma cells

Plumbagin, an important phytochemical from the roots of the medicinal plant Plumbago zeylanica L. has shown many biological activities. The roots of this plant have been in use in the Indian system of medicine for more than twenty five centuries for treatments of various ailments. It has shown anticancer activities, however, the anticancer and anti-metastatic effects of plumbagin are largely unknown against cervical cancer cells. Herein, we investigated the molecular alterations associated with plumbagin-mediated inhibition of growth, survival and epithelial to mesenchymal transition of human cervical cancer SiHa and HeLa cells. Plumbagin (1–4 μM) caused a significant decrease in the cell viability and increased the cell death in SiHa and Hela cells after 24 and 48 h. Plumbagin also caused strong G2/M and S-G2/M phase cell cycle arrest in SiHa and HeLa cells, respectively which was accompanied by a decrease in the expression of cyclin and CDK levels. The expression levels of both mRNAs and proteins of cyclin B1, A and E2 and CDK 1 and 2 decreased after 24 and 48 h. Plumbagin strongly induced apoptosis along with increased ratio of Bax : Bcl2 and cleavage of caspase 3, 9, and PARP. Plumbagin caused a significant increase in reactive oxygen species generation which mediated cell death as it was attenuated by pre-treatment with N-acetyl cysteine. Additionally, we also report for the first time that plumbagin possesses an anti-metastatic effect at non-cytotoxic doses that was accompanied by the modulation of MMP-2, 9, E-cadherin, N-cadherin, β-catenin and vimentin. Taken together, our findings suggest that plumbagin has strong anticancer and anti-metastatic effects against human cervical cancer cells.

Proposed mechanism of action of plumbagin in human cervical carcinoma SiHa and HeLa cells.     

Indirubin-3-monooxime induced cell cycle arrest and apoptosis in Hep-2 human laryngeal carcinoma cells

The commercially available analogue of indirubin, indirubin-3-oxime, is known for its antitumor activities. To further establish its role in anticancer activity, we tested its potential against human laryngeal carcinoma cell line (Hep-2). We investigated the molecular mechanisms of indirubin-induced apoptosis and growth arrest in human laryngeal carcinoma cells. Upon treatment with indirubin-3-monooxime, a time dependent inhibition of cell growth was observed and cells developed many hallmark features of apoptosis. The increase of chromatin condensation after treatment with indirubin-3-oxime identified by staining with chromatin stain Hoechst 333258 indicates apoptosis. The observed increase in DNA fragmentation after indirubin-3-oxime in DNA gel electrophoresis indicates the apoptotic feature exhibited by the drug. Flow cytometric analysis confirmed that indirubin increased populations of apoptotic phase G1. Indirubin-3-oxime-induced growth inhibition was associated with induction of Cdk inhibitor p21, inhibition of cyclin D1 and activation of caspase-3. We conclude that indirubin-3-oxime induces cell death and apoptosis in human laryngeal carcinoma cells.     

Induction of cell cycle arrest and apoptosis by 5-fluorouracil in laryngeal cancer cells containing HPV16 E6 and E7 oncoproteins

ObjectiveTo investigate the cytotoxic effect of 5-fluorouracil (5Fu) on HPV16-associated laryngeal cancer cells.Design and methodsCytotoxicity assay and TUNEL assay were used to assess the effect of 5Fu on laryngeal cancer cells transfected with HPV16 E6 or E7.Results5Fu induced apoptosis in the cells either with or without HPV16 in a dose- and time-dependent manner. 5Fu caused the accumulation of active pRb and p21^WAF1/CIP1, together with an increase in Bak and Bax expression and a decrease in Bcl-2 levels in all the transfected cells. G₁/S phase cell cycle arrest was associated with the antiproliferation activity of 5Fu. 5Fu also presented some effects on the E6 and E7 oncoproteins.ConclusionsHPV16 E6 and E7 oncoproteins do not prevent 5Fu-medicated apoptosis and G₁/S cell arrest in laryngeal cancers. The sensitivity of 5Fu treatment is associated with the decrease of Bcl-2 and/or the increase in Bak and p21^WAFI/CIP1.