Induced Apoptosis (induced + apoptosi)

Distribution by Scientific Domains

Selected Abstracts

Morphological irregularities and features of resistance to apoptosis in the dcp-1/pita double mutated egg chambers during Drosophila oogenesis

CYTOSKELETON, Issue 1 2005
Ioannis P. Nezis
Abstract In the present study, we demonstrate the most novel characteristic morphological features of Drosophila egg chambers lacking both dcp-1 and pita functions in the germline cells. Dcp-1 is an effector caspase and it has been previously shown to play an important role during Drosophila oogenesis [McCall and Steller, 1998 : Science 279 : 230,234; Laundrie et al., 2003 : Genetics 165 : 1881,1888; Peterson et al., 2003 : Dev Biol 260 : 113,123]. The completion of sequencing and annotation of the Drosophila genome has revealed that the dcp-1 gene is nested within an intron of another distinct gene, called pita, a member of the C2H2 zinc finger protein family that regulates transcriptional initiation. The dcp-1,/,/pita,/, nurse cells exhibit euchromatic nuclei (delay of apoptosis) during the late stages of oogenesis, as revealed by conventional light and electron microscopy. The phalloidin-FITC staining discloses significant defects in actin cytoskeleton arrangement. The actin bundles fail to organize properly and the distribution of actin filaments in the ring canals is changed compared to the wild type. The oocyte and the chorion structures have been also modified. The oocyte nucleus is out of position and the chorion appears to contain irregular foldings, while the respiratory filaments obtain an altered morphology. The dcp-1,/,/pita,/, egg chambers do not exhibit the rare events of spontaneously induced apoptosis, observed for the wild type flies, during mid-oogenesis. Interestingly, the mutated egg chambers are protected by staurosporine-induced apoptosis in a percentage of 40%, strongly suggesting the essential role of dcp-1 and/or pita during mid-oogenesis. Cell Motil. Cytoskeleton 60:14,23, 2005. 2004 Wiley-Liss, Inc. [source]

COX-2 inhibits Fas-mediated apoptosis in cholangiocarcinoma cells

HEPATOLOGY, Issue 3 2002
Ugochukwu C. Nzeako
Fas expression has been shown to negatively regulate the progression of cholangiocarcinoma cells in xenografts. However, many human cholangiocarcinomas express Fas, suggesting these cancers have developed mechanisms to inhibit Fas-mediated apoptosis. Cyclooxygenase-2 (COX-2), which generates prostanoids, is expressed by many cholangiocarcinomas. Therefore, our aim was to determine whether COX-2 expression inhibits death receptor,mediated apoptosis in KMBC cells, a cholangiocarcinoma cell line. These cells express messenger RNA for the death receptors Fas, tumor necrosis factor receptor 1 (TNF-R1), death receptor 4 (DR4), and DR5. Agonists for these death receptors, CH-11, TNF-,, and TRAIL all induced apoptosis. However, COX-2, whether induced by proinflammatory cytokines or transient transfection, only significantly inhibited Fas-mediated apoptosis. The COX-2 inhibitor NS-398 restored Fas-mediated apoptosis in COX-2 transfected cells. Prostaglandin E2 reduced apoptosis and mitochondrial depolarization after treatment with the Fas agonist CH-11. Of a variety of antiapoptotic proteins examined, COX-2/prostaglandin E2 only increased expression of Mcl-1, an antiapoptotic member of the Bcl-2 family. In conclusion, these data suggest that prostanoid generation by COX-2 specifically inhibits Fas-mediated apoptosis, likely by up-regulating Mcl-1 expression. Pharmacologic inhibition of COX-2 may be useful in augmenting Fas-mediated apoptosis of cholangiocarcinoma cells. [source]

Synthesis and in-vitro antitumour activity of new naphthyridine derivatives on human pancreatic cancer cells

Irene Banti
Abstract Objectives The aim of the study was to evaluate the antitumour effect in vitro of newly synthesized 7-substituted 2,3-dihydro-1,8-naphthyridines. Methods Characterization tools included cell viability assay, caspase 3/7 induction, DNA fragmentation, fibroblast growth factor type 1 receptor kinase inhibition, and in-vitro antiangiogenic analysis. Key findings Treatment of MIA PaCa-2 human pancreatic cancer cells with test compounds showed time- and concentration-dependent cytotoxicity with IC50 values in the micromolar range. Compounds with an aminoalkyl or a diaminoalkyl side chain at the 7-position exhibited remarkable cytotoxicity, whereas the presence of a methyl group or a cyclic amine in the same position led to a significant decrease in their biological activity. Cytotoxicity screening demonstrated that the most active was compound 11 (mean 50% inhibition of cell proliferation (IC50) 11 ,M). This compound had an in-vitro antitumour efficacy superior to 5-fluorouracil (the lowest cell viability value after treatment (Emax) 0.2% and 19%, respectively) and proved to be less toxic than 5-fluorouracil against non-cancerous human oral epithelial cells. In addition, compound 11 induced apoptosis in MIA PaCa-2 cells and it was able to promote antiangiogenic effects in vitro. Finally, its cytotoxicity was enhanced in pancreatic cancer cells stimulated with fibroblast growth factor, while no substantial effect was observed on human bronchial smooth muscle cells stimulated with the same growth factor. Conclusions These findings suggest that 1,8-naphthyridine derivatives are a promising class of compounds in cancer research. In particular, the antitumour activity of compound 11 is worth further investigation. [source]

Cytotoxic activity of an octadecenoic acid extract from Euphorbia kansui (Euphorbiaceae) on human tumour cell strains

Farong Yu
We have investigated the cytotoxic and antitumour activity of an octadecenoic acid extract, mainly containing oleic and linoleic acids, from Euphorbia kansui on human gastric (SGC-7901), hepatocellular carcinoma (BEL-7402), and leukaemia (HL-60) tumour cell strains. Significant and dose-dependent antiproliferation effects were observed on tumour cells from the dose of 3.2 ,g mL,1, which were comparable with or better than those of the common antitumour agent 5-fluorouracil. Results from the clone formation assay and flow cytometry indicated that the mixture of octadecenoic acids resulted in a dose-dependent reduction in the number of tumour cells and significantly inhibited cell proliferation, with induced apoptosis and G0/G1 phase cell cycle arrest. Also, the octadecenoic acids could not only cause cell apoptosis/necrosis but also functionally and structurally damage the tumour cell membrane and cell ultra-structures. These observations encourage further clinical evaluation of the inhibitory effects of octadecenoic acids on various forms of cancer. [source]

Induction of apoptosis of RAW 264.7 cells by the cytostatic macrolide apicularen A

JangJa Hong
ABSTRACT In RAW 264.7 cells, a mouse leukaemic monocyte cell line, apicularen A decreased cell growth and survival as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in a concentration-dependent manner at 10,1000 nM. Apicularen B, an N -acetyl-glucosamine glycoside of apicularen A, was 10,100-fold less effective than apicularen A. Apicularen A induced a DNA ladder, an increase in the percentage of sub-G1 cells and annexin V-binding cells, and promoted the activation of caspase as revealed by the cleavage of poly(ADP-ribose) polymerase, indicating that apicularen A induced apoptosis in RAW 264.7 cells. In addition, apicularen A phosphorylated p44/42 mitogen-activated protein kinase (MAPK) and p38 MAPK. The p44/42 MAPK inhibitor PD98059 rescued the cells from apicularen-induced decrease in cell growth and survival as determined by the MTT assay, while the p38 MAPK inhibitor SB203580 augmented the effect of apicularen A. This suggested the activation of p44/42 MAPK to be pro-apoptotic and the activation of p38 MAPK anti-apoptotic in apicularen A-treated RAW 264.7 cells. [source]

Thimerosal induces apoptosis and G2/M phase arrest in human leukemia cells,

Kyung Jin Woo
Abstract Thimerosal is an organomercury compound with sulfhydryl-reactive properties. The ability of thimerosal to act as a sulfhydryl group is related to the presence of mercury. Due to its antibacterial effect, thimerosal is widely used as preservatives and has been reported to cause chemically mediated side effects. In the present study, we showed that the molecular mechanism of thimerosal induced apoptosis in U937 cells. Thimerosal was shown to be responsible for the inhibition of U937 cells growth by inducing apoptosis. Treatment with 2.5,5 M thimerosal but not thiosalicylic acid (structural analog of thimerosal devoid of mercury) for 12 h produced apoptosis, G2/M phase arrest, and DNA fragmentation in a dose-dependent manner. Treatment with caspase inhibitor significantly reduced thimerosal-induced caspase 3 activation. In addition, thimerosal-induced apoptosis was attenuated by antioxidant Mn (III) meso-tetrakis (4-benzoic acid) porphyrin (Mn-TBAP). These data indicate that the cytotoxic effect of thimerosal on U937 cells is attributable to the induced apoptosis and that thimerosal-induced apoptosis is mediated by reactive oxygen species generation and caspase-3 activation. 2006 Wiley-Liss, Inc. [source]