benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone and Adenocarcinoma

Ajoene, a garlic-derived organosulfur compound, exerts anti-tumorigenic effect against various cancers. However, little is known about the biological effect of ajoene on lung adenocarcinoma, an aggressive malignancy with dismal prognosis. We investigated the biological effect of ajoene on lung adenocarcinoma and the underlying pathway. Lung adenocarcinoma cells A549, NCI-H1373, and NCI-H1395, along with the noncancerous lung bronchus cells BEAS-2B, were used. MTT test showed that ajoene (25 μM) reduces viability of lung adenocarcinoma cells but not the noncancerous BEAS-2B cells. Bromodeoxyuridine incorporation assay revealed that ajoene inhibits proliferation of lung adenocarcinoma cells. Treatment of lung adenocarcinoma cells with ajoene enhances apoptosis and ROS generation in a time- and dose-dependent fashion. Abrogation of caspase activation by zVAD-fmk completely prevents the ajoene-induced apoptosis; whereas block of ROS generation by N-acetylcysteine partly abolishes the ajoene-induced apoptosis. ROS-mediated induction of apoptosis contributes partially to the anti-tumorigenic property of ajoene observed, a phenomenon also confirmed by xenograft tumor study. Mitogen activated protein kinases (MAPKs), pivots of ROS-mediated signaling pathway, are activated upon ajoene treatment; Jun-N-terminal kinase (JNK)/p38 activations are required for signaling pathway underlying the ajoene-induced apoptosis. Our results suggest that ROS-mediated activation of JNK/p38 contributes partially to the pro-apoptotic action of ajoene on cells of lung adenocarcinoma. Ajoene may be a promising chemotherapeutic agent for lung adenocarcinoma.

Topics: A549 Cells; Adenocarcinoma; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Caspase Inhibitors; Caspases; Cell Line; Cell Line, Tumor; Cell Survival; Disulfides; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Humans; Immunoblotting; JNK Mitogen-Activated Protein Kinases; Lung Neoplasms; Male; Mice, Nude; p38 Mitogen-Activated Protein Kinases; Reactive Oxygen Species; Signal Transduction; Sulfoxides; Time Factors; Xenograft Model Antitumor Assays

Tanshinone IIA (T2A), a derivative of phenanthrenequinone and also the major active ingredient of Danshen, has been paid extensive attention as a promising cancer therapy for its potential anti-cancer activities. In this study, the apoptosis and autophagy of human prostate cancer PC-3 cells were observed after 5 μM T2A treatment, as well as their relevance. Mitochondrial-dependent apoptosis was firstly detected through morphological observation and biochemical analysis. Meanwhile, 5 μM T2A successfully triggered the autophagy of PC-3 cells, indicated by increased expression of Beclin1, and LC3 II. Validation experiments were conducted to further consolidate T2A's contribution to autophagy: Pretreatment with autophagy inhibitor 3-methyladenine (3-MA) provided protection against autophagy and enhanced T2A-induced apoptosis. Besides, the apoptosis suppressor z-VAD-fmk failed to facilitate the formation of autophagic vacuoles, which also proved the T2A-induced autophagy independent of apoptosis. Moreover, the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) efficiently inhibited the expression of Beclin1, LC3-II, and cleaved caspase-3, which indicated apoptosis and autophagy with dependence on intracellular ROS production. Taken together, these results demonstrated that autophagy is the cytoprotective mechanism in this experimental system, and the ROS resulted from T2A treatment played a critical role in apoptosis and autophagy initiation.

Topics: Abietanes; Acetylcysteine; Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; Autophagy; Beclin-1; Caspase 3; Cell Line, Tumor; Drug Screening Assays, Antitumor; Humans; Male; Microtubule-Associated Proteins; Neoplasm Proteins; Prostatic Neoplasms; Reactive Oxygen Species

The purpose of the study was to evaluate the therapeutic benefit of treatments with carfilzomib (CFZ) and z-VAD-fmk in a mouse model of cancer-induced cachexia. The model of cancer-associated cachexia was generated by injecting murine C26 adenocarcinoma cells into BALB/C mice. CFZ and z-VAD-fmk were administered individually or in combination at 5 and 12 days after inoculation. Changes in body weight, gastrocnemius muscle mass, tumor burden, spontaneous activity, survival, and metabolic profiles were noted. Also evaluated were the circulatory levels of renin and angiotensin II, and levels of apoptotic, proteolytic, and renin-angiotensin system-associated markers and transcription factor 2 (ATF2) in gastrocnemius muscle. The CFZ and z-VAD-fmk treatments were associated with less muscle wasting, reduced tumor burden, modulated metabolism, higher levels of glucose, albumin, and total proteins, and lower levels of triglyceride fatty acids, more spontaneous physical activity, and longer survival in C26-inoculated mice compared with PBS-treated cachectic mice. CFZ and z-VAD-fmk treatments resulted in higher levels of caspase-3 and BAX and lower level of BCL-XL in gastrocnemius muscles and altered the level of proteins in the renin-angiotensin system. The combined treatment administered 5 days after C26 inoculation was more effective than other regimens. Combined treatment with CFZ and z-VAD-fmk early in the development of cachexia was associated with signs of less proteolysis and apoptosis and less severe cachexia in a mouse model of cancer-induced cachexia.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Blotting, Western; Cachexia; Cell Proliferation; Drug Therapy, Combination; Humans; Immunoenzyme Techniques; Male; Mice; Mice, Inbred BALB C; Muscle, Skeletal; Neuroprotective Agents; Oligopeptides; Proteolysis; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Cells, Cultured; Ubiquitination

Anacardic acid (AA) is a constituent of the cashew nut shell and is known as an inhibitor of nuclear factor-κB (NF-κB). We investigated the cytotoxicity of AA on cancer cells and more experiments to reveal the cell death mechanism focused on A549 lung adenocarcinoma cells for our interest in lung cancer. To examine the molecular mechanism of cell death in AA treated A549 cells, we performed experiments such as transmission electron microscopy (TEM), western blot analysis, fluorescence-activated cell sorting (FACS), genomic DNA extraction and staining with 4',6-diamidino-2-phenylindole (DAPI). For the first time we revealed that AA induces caspase-independent apoptosis with no inhibition of cytotoxicity by pan-caspase inhibitor, Z-VAD-fmk, in A549 cells. Our results showed the possibility of mitochondrial-mediated apoptosis through the activation of apoptosis-inducing factor (AIF) and an intrinsic pathway executioner such as cytochrome c. This study will be helpful in revealing the cell death mechanisms and in developing potential drugs for lung cancer using AA.

Topics: Adenocarcinoma; Adenocarcinoma of Lung; Amino Acid Chloromethyl Ketones; Anacardic Acids; Apoptosis; Apoptosis Inducing Factor; Caspase Inhibitors; Caspases; Cell Line, Tumor; Cytochromes c; Enzyme Activation; HEK293 Cells; Hep G2 Cells; Humans; Lung Neoplasms; Mitochondria; NF-kappa B; Signal Transduction

Baohuoside I (also known as Icariside II) is a flavonoid isolated from Epimedium koreanum Nakai. Although Baohuoside I exhibits anti-inflammatory and anti-cancer activities, its molecular targets/pathways in human lung cancer cells are poorly understood. Therefore, in the present study, we investigated the usefulness of Baohuoside I as a potential apoptosis-inducing cytotoxic agent using human adenocarcinoma alveolar basal epithelial A549 cells as in vitro model. The apoptosis induced by Baohuoside I in A549 cells was confirmed by annexin V/propidium iodide double staining, cell cycle analysis and dUTP nick end labeling. Further research revealed that Baohuoside I accelerated apoptosis through the mitochondrial apoptotic pathway, involving the increment of BAX/Bcl-2 ratio, dissipation of mitochondrial membrane potential, transposition of cytochrome c, caspase 3 and caspase 9 activation, degradation of poly (ADP-ribose) polymerase and the over-production of reactive oxygen species (ROS). A pan-caspase inhibitor, Z-VAD-FMK, only partially prevented apoptosis induced by Baohuoside I, while NAC, a scavenger of ROS, diminished its effect more potently. In addition, the apoptotic effect of Baohuoside I was dependent on the activation of ROS downstream effectors, JNK and p38(MAPK), which could be almost abrogated by using inhibitors SB203580 (an inhibitor of p38(MAPK)) and SP600125 (an inhibitor of JNK). These findings suggested that Baohuoside I might exert its cytotoxic effect via the ROS/MAPK pathway.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Carcinoma, Non-Small-Cell Lung; Caspase 3; Caspase Inhibitors; Cell Line, Tumor; Cytochromes c; Drug Screening Assays, Antitumor; Flavonoids; Humans; Lung Neoplasms; MAP Kinase Kinase 4; Membrane Potential, Mitochondrial; Mitochondria; p38 Mitogen-Activated Protein Kinases; Poly(ADP-ribose) Polymerases; Reactive Oxygen Species

Silibinin, a flavonolignan isolated from the milk thistle plant (Silybum marianum), possesses anti-neoplastic properties. In vitro and in vivo studies have recently shown that silibinin inhibits the growth of colorectal cancer (CRC). The present study investigates the mechanisms of silibinin-induced cell death using an in vitro model of human colon cancer progression, consisting of primary tumor cells (SW480) and their derived metastatic cells (SW620) isolated from a metastasis of the same patient. Silibinin induced apoptotic cell death evidenced by DNA fragmentation and activation of caspase-3 in both cell lines. Silibinin enhanced the expression (protein and mRNA) of TNF-related apoptosis-inducing ligand (TRAIL) death receptors (DR4/DR5) at the cell surface in SW480 cells, and induced their expression in TRAIL-resistant SW620 cells normally not expressing DR4/DR5. Caspase-8 and -10 were activated demonstrating the involvement of the extrinsic apoptotic pathway in silibinin-treated SW480 and SW620 cells. The protein Bid was cleaved in SW480 cells indicating a cross-talk between extrinsic and intrinsic apoptotic pathway. We demonstrated that silibinin activated also the intrinsic apoptotic pathway in both cell lines, including the perturbation of the mitochondrial membrane potential, the release of cytochrome c into the cytosol and the activation of caspase-9. Simultaneously to apoptosis, silibinin triggered an autophagic response. The inhibition of autophagy with a specific inhibitor enhanced cell death, suggesting a cytoprotective function for autophagy in silibinin-treated cells. Taken together, our data show that silibinin initiated in SW480 and SW620 cells an autophagic-mediated survival response overwhelmed by the activation of both the extrinsic and intrinsic apoptotic pathways.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents; Apoptosis; Autophagy; BH3 Interacting Domain Death Agonist Protein; Caspase 10; Caspase 3; Caspase 8; Caspase Inhibitors; Cell Line, Tumor; Colonic Neoplasms; Humans; Macrolides; Oligopeptides; Receptors, TNF-Related Apoptosis-Inducing Ligand; Signal Transduction; Silybin; Silymarin; TNF-Related Apoptosis-Inducing Ligand; Up-Regulation

Several studies have shown that curcumin can induce apoptosis and inhibit growth in human tumor cell lines. However, the mechanism is not completely understood yet. The present studies were designed to investigate the effects of curcumin on human A549 lung adenocarcinoma cells lines to better understand its effect on apoptosis and apoptosis-related genes in vitro. Apoptosis induction, mitochondria membrane potential, mitochondria structure, and apoptotic associated gene expression were examined by flow cytometric assay, confocal microscopy, Western blotting and electron microscopy. After treatment with curcumin, percentage of apoptotic cells increased dose- and time-dependently, and morphology observation revealed typical apoptotic features. Our data further indicated that the expression of Bax proteins in A549 cells was increased in a dose-dependent manner, whereas the expression of Bcl-2 was significantly decreased, thus the ratio of Bax/Bcl-2 was increased. The apoptotic process was accompanied by the change of mitochondrial function and structure which led to release of the cytochrome c, and activation of caspase-9 and caspase-3. Furthermore, curcumin also induced a dose-dependent cleavage of PARP. Caspases activation during the course of curcumin-induced apoptosis was additionally confirmed by using a broad-spectrum caspases inhibitor, Z-VAD-fmk. As expected, the inhibitor was able to decrease curcumin-induced apoptosis on A549 cells. These results suggested that mitochondria played an important role in the curcumin-induced apoptosis, and mitochondria membrane potential loss initiated apoptosis via the activation of caspases.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Shape; Curcumin; Cysteine Proteinase Inhibitors; Cytochromes c; Dose-Response Relationship, Drug; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Membrane Potential, Mitochondrial; Microscopy, Confocal; Microscopy, Electron, Transmission; Mitochondria; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Time Factors

This study was aimed to evaluate the apoptotic effects of thiosulfinates purified from Allium tuberosum L. on PC-3 human prostate cancer cells, and to elucidate detailed apoptosis mechanisms. Thiosulfinates significantly decrease viable cell numbers in dose- and time-dependent manners by apoptotic cell death via DNA fragmentation, chromatin condensation, and an increased sub-G1 phase. Apoptosis induced by thiosulfinates is associated with the activation of initiator caspase-8 and -9, and the effector caspase-3. In this study, thiosulfinates stimulated Bid cleavage, indicating that the apoptotic action of caspase-8-mediated Bid cleavage leads to the activation of caspase-9. Thiosulfinates decreased the expression of the anti-apoptotic protein Bcl-2 and increased the expression of the pro-apoptotic protein Bax. Thiosulfinates also increased the expression of AIF, a caspase-independent mitochondrial apoptosis factor, in PC-3 cells. These results indicate that thiosulfinates from A. tuberosum L. inhibit cell proliferation and induce apoptosis in PC-3 cells, which may be mediated via both caspase-dependent and -independent pathways.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; Apoptosis Inducing Factor; bcl-2-Associated X Protein; Caspase Inhibitors; Caspases; Cell Growth Processes; Cell Line, Tumor; Chive; Collagen Type XI; Drug Screening Assays, Antitumor; Enzyme Activation; Enzyme Inhibitors; Humans; Male; Mitochondria; Plant Extracts; Prostatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Sulfinic Acids

Increasing evidence demonstrated that denbinobin, isolated from Ephemerantha lonchophylla, exert cytotoxic effects in cancer cells. The purpose of this study was to investigate whether denbinobin induces apoptosis and the apoptotic mechanism of denbinobin in human lung adenocarcinoma cells (A549). Denbinobin (1-20microM) caused cell death in a concentration-dependent manner. Flow cytometric analysis and annexin V labeling demonstrated that denbinobin increased the percentage of apoptotic cells. A549 cells treated with denbinobin showed typical characteristics of apoptosis including morphological changes and DNA fragmentation. Denbinobin induced caspase 3 activation, and N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD-fmk), a broad-spectrum caspase inhibitor, prevented denbinobin-induced cell death. Denbinobin induced the loss of the mitochondrial membrane potential and the release of mitochondrial apoptotic proteins including cytochrome c, second mitochondria derived activator of caspase (Smac), and apoptosis-inducing factor (AIF). In addition, denbinobin-induced Bad activation was accompanied by the dissociation of Bad with 14-3-3 and the association of Bad with Bcl-xL. Furthermore, denbinobin induced Akt inactivation in a time-dependent manner. Transfection of A549 cells with both wild-type and constitutively active Akt significantly suppressed denbinobin-induced Bad activation and cell apoptosis. These results suggest that Akt inactivation, followed by Bad activation, mitochondrial dysfunction, caspase 3 activation, and AIF release, contributes to denbinobin-induced cell apoptosis.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Anthraquinones; Antineoplastic Agents, Phytogenic; Apoptosis; Apoptosis Inducing Factor; Apoptosis Regulatory Proteins; bcl-Associated Death Protein; Caspase 3; Caspase Inhibitors; Cell Count; Cell Line, Tumor; Cell Survival; Cysteine Proteinase Inhibitors; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Intracellular Signaling Peptides and Proteins; Lung Neoplasms; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Membranes; Mitochondrial Proteins; Oncogene Protein v-akt; Phenanthrenes

The rate of gossypol-induced apoptosis does not correlate very well with the same dose of gossypol-induced cell growth inhibition, indicating an anti-proliferative effect of gossypol. Using a co-immunoprecipitation assay, it was observed that the level of Bcl-X(L) protein bound to Bax was clearly lower than that of Bcl-2 protein at 5 micro M of gossypol treatment, and the level of Bim protein bound to Bcl-X(L) was lowered at 20 micro M of gossypol treatment for 24 h, implicating that gossypol inhibits the heterodimerization of Bcl-X(L) with Bax and Bim. Gossypol-induced apoptosis is partly suppressed by as low as 0.5 micro M, but not abolished by as high as 50 micro M of a broad range caspase inhibitor, Z-VAD-FMK, suggesting that gossypol-induced apoptosis is both caspase-dependent and -independent. Furthermore, the release of apoptosis inducing factor (AIF), which triggers caspase-independent apoptosis, from mitochondria to cytosol was observed in PC-3 cells exposed to gossypol treatment. In conclusion, gossypol inhibits the proliferation and induces apoptosis in PC-3 cells. Gossypol-induced apoptosis is, at least, through inhibiting the heterodimerization of Bcl-X(L)/Bcl-2 with pro-apoptosis molecules, followed by a caspase-dependent and -independent process which involves the release of AIF from the mitochondria to cytosol.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Apoptosis; Apoptosis Inducing Factor; Apoptosis Regulatory Proteins; bcl-2-Associated X Protein; Bcl-2-Like Protein 11; bcl-X Protein; Caspase Inhibitors; Caspases; Cell Line, Tumor; Cell Proliferation; Contraceptive Agents, Male; Cysteine Proteinase Inhibitors; Dose-Response Relationship, Drug; Gossypol; Humans; Male; Membrane Proteins; Prostatic Neoplasms; Protein Binding; Proto-Oncogene Proteins

Prostate cancer is one of the most common cancers in men, with more than 500,000 new worldwide cases reported annually, resulting in 200,000 deaths of mainly older men in developed countries. Existing treatments have not proved very effective in managing prostate cancer, and continuing efforts therefore are ongoing to explore novel targets and strategies for future therapies. LAPSER1 has been identified as a candidate tumor suppressor gene in prostate cancer, but its true functions remain unknown. We report here that LAPSER1 colocalizes to the centrosomes and midbodies in mitotic cells with gamma-tubulin, MKLP1, and p80 katanin, and is involved in cytokinesis. Moreover, RNAi-mediated disruption of LAPSER1, which is accompanied by the mislocalization of p80 katanin, results in malformation of the central spindle. Significantly, the enhanced expression of LAPSER1 induces binucleation and renders the cells resistant to oncogenic transformation. In cells transformed by the v-Fps oncogene, overexpressed LAPSER1 induces abortive cytokinesis, followed by mitotic catastrophe in a p80 katanin-dependent manner. Cells that are rescued from this apoptotic pathway with Z-VAD-fmk display karyokinesis. These results suggest that LAPSER1 participates in cytokinesis by interacting with p80 katanin, the disruption of which may potentially cause genetic instability and cancer.

Topics: Adenocarcinoma; Adenosine Triphosphatases; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Bone Neoplasms; Cell Line; Cell Line, Transformed; Cell Line, Tumor; Cell Transformation, Viral; Centrosome; CHO Cells; Cricetinae; Cricetulus; Cytokinesis; Fusion Proteins, gag-onc; Genes, Tumor Suppressor; Humans; Katanin; Leucine Zippers; Male; Membrane Proteins; Microtubule-Associated Proteins; Oncogene Protein p21(ras); Oncogene Proteins v-abl; Osteosarcoma; Polyploidy; Prostatic Neoplasms; Protein Subunits; Protein-Tyrosine Kinases; Rats; Recombinant Fusion Proteins; RNA Interference; RNA, Small Interfering; Spindle Apparatus; Subcellular Fractions; Tubulin; Tumor Suppressor Proteins

The present study was undertaken to gain insights into the molecular mechanism of apoptosis induction by phenethyl isothiocyanate (PEITC) using prostate cancer cell lines derived from transgenic adenocarcinoma mouse prostate (TRAMP) mice (TRAMP-C1 and TRAMP-C2).. The viability of TRAMP-C1 and TRAMP-C2 cells was reduced significantly in the presence of PEITC in a concentration-dependent manner as determined by sulforhodamine B and trypan blue dye exclusion assays. Treatment of TRAMP-derived cells with PEITC revealed features characteristic of apoptosis induction, including appearance of subdiploid cells (determined by flow cytometry), cytoplasmic histone-associated DNA fragmentation (determined by an ELISA assay), and cleavage of caspase-3 (determined by immunoblotting). The PEITC-induced apoptosis in TRAMP-derived cells was associated with a marked increase in the level of proapoptotic protein Bak and/or a decrease in the levels of antiapoptotic protein Mcl-1 or Bcl-xL and disruption of mitochondrial membrane potential. The SV40 immortalized mouse embryonic fibroblasts derived from Bak and Bax double knockout mice were significantly more resistant to PEITC-induced DNA fragmentation compared with wild-type or Bak-/- mouse embryonic fibroblasts. The PEITC-induced apoptosis in both cell lines was significantly attenuated in the presence of caspase inhibitors zVAD-fmk, zLEHD-fmk, and zIETD-fmk. Oral administration of PEITC (9 or 12 micromol PEITC/d, Monday-Friday) significantly retarded growth of TRAMP-C1 xenografts in nude mice without causing weight loss or any other side effects.. The results of the present study indicate that caspase-dependent apoptosis by PEITC is mediated by Bak and Bax proteins.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Caspase Inhibitors; Caspases; Cell Line, Tumor; Cell Survival; Cysteine Proteinase Inhibitors; Dose-Response Relationship, Drug; Immunoblotting; Intracellular Membranes; Isothiocyanates; Male; Membrane Potentials; Membrane Proteins; Mice; Mice, Knockout; Mice, Transgenic; Mitochondria; Neoplasms; Plant Preparations; Prostatic Neoplasms; Proto-Oncogene Proteins c-bcl-2; Vegetables

Colon epithelial cells have a defined life span and undergo terminal differentiation as they mature and migrate to the luminal surface. The differentiation process can be induced in cultured colon cancer cells by sodium butyrate, which induces expression of various differentiation markers followed subsequently by cell death. In the present study, HT29 colorectal carcinoma cells were shown to undergo butyrate-induced caspase activation that was mainly produced through a mitochondrial pathway. Inhibition of caspase activation, either by peptide pan caspase inhibitor Z-VAD-FMK, by caspase 9 inhibitor Z-LEHD-FMK, or by overexpression of Bcl-XL, also inhibited the expression of differentiation markers. These findings suggest (a) that terminal differentiation of HT29 colon carcinoma cells is tightly linked to caspase activation and (b) that increased expression of anti-apoptotic members of the Bcl-2 family of proteins, as well as other inhibitors of caspase activation, has the potential to inhibit terminal differentiation and thereby may contribute to the progression of colon cancer.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Apoptosis; bcl-X Protein; Butyrates; Caspase Inhibitors; Caspases; Cell Line, Tumor; Cell Survival; Cell Transformation, Neoplastic; Colonic Neoplasms; Enzyme Activation; Humans; Oligopeptides; Proto-Oncogene Proteins c-bcl-2

LIGHT is a new member of the tumor necrosis factor superfamily, which binds to lymphotoxin beta receptor, herpes virus entry mediator, or TR6. This work was carried out to elucidate the molecular mechanism of LIGHT-sensitized, interferon gamma (IFNgamma)-mediated apoptosis of MDA-MB-231 cells. It was revealed that LIGHT treatment resulted in down-regulation of anti-apoptosis Bcl-2 family member: Bcl-2, Bcl-X(L), Bag-1, and Mcl-1; up-regulation of pro-apoptosis Bcl-2 family member: Bak and Ser (112)-phosphor-Bad; down-regulation of pro-apoptosis Bcl-2 member Bax; the other pro-apoptosis member Bid remains unaltered. LIGHT treatment also resulted in activation of caspase-3, caspase-6, caspase-7, caspase-8, caspase-9, DFF45, and PARP. However, caspase activation and caspase activity, especially caspase-3 activity, is not required for LIGHT-induced apoptosis of MDA-MB-231 cells, since caspase-3 inhibitor, benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone, and a broad range caspase inhibitor, benzyloxycarbonyl-val-ala-asp-fluoromethylketone failed to block the apoptosis induced by LIGHT and IFNgamma in MDA-MB-231 cells. In summary, LIGHT-sensitized IFNgamma-mediated apoptosis of MDA-MB-231 cells is probably through down-regulation of anti-apoptosis Bcl-2 family members; it could be caspase (especially caspase-3)-independent, even though extensive caspase activation was observed.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Apoptosis; Apoptosis Regulatory Proteins; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; bcl-X Protein; BH3 Interacting Domain Death Agonist Protein; Breast Neoplasms; Carrier Proteins; Caspases; Cysteine Proteinase Inhibitors; DNA-Binding Proteins; Enzyme Activation; Female; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Humans; Interferon-gamma; Membrane Proteins; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Oligopeptides; Poly(ADP-ribose) Polymerases; Proteins; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Transcription Factors; Tumor Cells, Cultured; Tumor Necrosis Factor Ligand Superfamily Member 14; Tumor Necrosis Factor-alpha

Apoptosis induced by DNA-damaging agents or radiation mainly proceeds through death receptor-independent caspase activation. The release of mitochondrial apoptogenic proteins, such as cytochrome c, into the cytoplasm leading to Apaf1-dependent activation of caspase-9 is a key event in this pathway. The permeability of the mitochondrial outer membrane is regulated by the various pro- and antiapoptotic Bcl-2 family proteins, and it is thought that DNA damage triggers apoptosis through the downregulation of antiapoptotic Bcl-2. Using murine embryonic fibroblasts (MEF) deficient and proficient in Apaf1, we show that DNA-damaging agents and radiation lead to a decline in Bcl-2 protein only in wt MEF, but not in apaf1(-/-) MEF, which are defective in the activation of effector caspases and apoptosis. In contrast, the induction of proapoptotic Noxa, the activation of Bax, the cytoplasmic release of cytochrome c, as well as a drop of the mitochondrial transmembrane potential Deltapsim are equally observed in wt and apaf1(-/-) MEF following DNA damage. Moreover, the loss of Bcl-2 protein occurring in wt MEF can be prevented by caspase inhibition. Hence, the activation of proapoptotic Bcl-2 family proteins rather than the downregulation of antiapoptotic Bcl-2 mediates the primary signal in the DNA damage-induced release of mitochondrial apoptogenic proteins in MEF.

Topics: Adenocarcinoma; Adenoviridae; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Apoptotic Protease-Activating Factor 1; Caspase Inhibitors; Caspases; Cell Transplantation; Dactinomycin; DNA Damage; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Enzyme Activation; Enzyme Inhibitors; Etoposide; Fibroblasts; Gene Deletion; Humans; Mice; Mice, SCID; Pancreatic Neoplasms; Proteins; Proto-Oncogene Proteins c-bcl-2; Transplantation, Heterologous; Tumor Cells, Cultured; Ultraviolet Rays

Progesterone (P4) has been implicated as a protective factor for epithelial ovarian cancers, yet little is known about its mechanism of action. We previously reported that pregnancy-equivalent doses of P4 inhibited the growth of normal and malignant human ovarian surface epithelial (HOSE) cells. Here, we investigated how P4-induced cell death in two immortalized normal (HOSE 642, HOSE 12-12) and two malignant (OVCA 429, OVCA 432) HOSE cell lines. The exposure of HOSE or OVCA cell cultures to 10(-6) M P4 induced time-dependent increases in early and late apoptotic cells and activation of caspase-8 and -3, but not that of caspase-9. A general caspase inhibitor Z-VAD effectively blocked the P4-induced cell death in a dose-dependent manner. Comparable levels of Fas mRNA and protein were expressed in HOSE and OVCA cell lines, and these levels were unaffected by P4. In contrast, levels of FasL mRNA and protein were higher in OVCA cells than in HOSE cells. Interestingly, the hormone enhanced levels of FasL mRNA and protein in HOSE cells, but lowered their levels in OVCA cells. The exposure of HOSE or OVCA cells to an activating anti-Fas antibody induced cell loss, whereas treatment of cells with a blocking anti-FasL antibody reduced the P4-induced cell loss. Cotreatment of cells with the activating anti-Fas antibody and P4 produced additive effects on cell loss. These results reveal for the first time that P4 induces apoptosis in HOSE and OVCA cells via activation of a caspase-8-initiated Fas/FasL signaling pathway. They also demonstrate differential P4-regulation of FasL expression between HOSE and OVCA cells.

Topics: Adenocarcinoma; Adult; Amino Acid Chloromethyl Ketones; Apoptosis; Caspase 8; Caspase 9; Caspases; Cell Division; Dose-Response Relationship, Drug; Drug Therapy, Combination; Enzyme Activation; Enzyme Inhibitors; Epithelial Cells; Fas Ligand Protein; Female; Gene Expression Regulation, Neoplastic; Humans; Membrane Glycoproteins; Middle Aged; Ovarian Neoplasms; Ovary; Progesterone; Signal Transduction; Tumor Cells, Cultured

We have found that omega-hydroxy palmitic acid (16-hydroxy palmitic acid, omega-HPA) has both cell growth inhibiting and cell death inducing actions on human lung adenosquamous carcinoma cell line H596 and adenocarcinoma cell line A549. Further, these effects were dose- and time-dependent in both cell lines. However, in squamous carcinoma cell line H226, omega-HPA had no cytotoxic effect. On the other hand, in the human small cell lung carcinoma (SCLC) cell line H128, this compound showed weak cytotoxicity. The sensitivity toward omega-HPA was higher in H596 cells than in A549 cells. In both H596 and A549 cells, cell growth was inhibited to 24.4 and 9.4%, respectively, by treatment with 100 microM omega-HPA for 12 h. In the 24 h treatment cells, growth inhibition was increased to 100 and 38.1%, respectively. In cytotoxicity experiments, the number of dead cells increased with incubation times in the presence of omega-HPA: on three days incubation with 100 microM omega-HPA, viability was 0 and 13.5%, respectively, in H596 and A549 cells. Further, the fragmentation of DNA to oligonucleosomal-sized ladder fragments, which is an index of apoptosis, was observed in both cell lines on treatment with omega-HPA. Therefore, it is assumed that these cell deaths induced by omega-HPA, were apoptosis in these cell lines. Since the number of dead cells following treatment with omega-HPA decreased by treatment with omega-HPA in combination with Z-VAD-fmk, a caspase family inhibitor, it is thought that apoptotic cell death was related to caspase activity.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents, Phytogenic; Apoptosis; Carcinoma; Carcinoma, Adenosquamous; Carcinoma, Squamous Cell; Caspase Inhibitors; Cell Division; Cell Line; Cell Survival; Cysteine Proteinase Inhibitors; DNA Fragmentation; DNA, Neoplasm; Dose-Response Relationship, Drug; Humans; Lung Neoplasms; Palmitic Acids; Time Factors; Tumor Cells, Cultured

All-trans-retinoic acid and 9-cis-retinoic acid have been reported to have inhibitory effects on pancreatic adenocarcinoma cells and we have shown that this is partly due to induction of apoptosis. In this study, the mechanisms whereby 9-cis-retinoic acid induces apoptosis in these cells were investigated. An involvement of the Bcl-2 family of proteins was shown, such that 9-cis-retinoic acid causes a decrease in the Bcl-2/Bax ratio. Overexpression of Bcl-2 also resulted in inhibition of apoptosis induced by 9-cis-retinoic acid. Furthermore, two broad-range caspase inhibitors blocked DNA fragmentation induced by 9-cis-retinoic acid, but had no effect on viability defined by mitochondrial activity. Using synthetic retinoids, which bind selectively to specific retinoic acid receptor subtypes, we further established that activation of retinoic acid receptor-gamma is essential for induction of apoptosis. Only pan-retinoic acid receptor and retinoic acid receptor-gamma selective agonists reduced viability and a cell line expressing very low levels of retinoic acid receptor-gamma is resistant to the effects of 9-cis-retinoic acid. A retinoic acid receptor-beta/gamma selective antagonist also suppressed the cytotoxic effects of 9-cis-retinoic acid in a dose-dependent manner. This study provides important insight into the mechanisms involved in suppression of pancreatic tumour cell growth by retinoids. Our results encourage further work evaluating the clinical use of receptor subtype selective retinoids in pancreatic carcinoma.

Topics: Adenocarcinoma; Alitretinoin; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Aspartic Acid; bcl-2-Associated X Protein; Cysteine Proteinase Inhibitors; DNA Fragmentation; Drug Resistance; Fatty Acids, Unsaturated; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Humans; Mice; Mitochondria; Neoplasm Proteins; Pancreatic Neoplasms; Protein Isoforms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Receptors, Retinoic Acid; Recombinant Fusion Proteins; Retinoic Acid Receptor gamma; Retinoid X Receptors; Retinoids; Transcription Factors; Transfection; Tretinoin; Tumor Cells, Cultured

The HT29 adenocarcinoma is a common model of epithelial cell differentiation and colorectal cancer and its death is an oft-analyzed response to TNF family receptor signaling. The death event itself remains poorly characterized and here we have examined the involvement of caspases using pan-caspase inhibitors. zVAD-fmk did not block death of HT29 cells in response to activation of the Fas, TRAIL, TNF, TWEAK and LTbeta receptors. The secondary induction of TNF or the other known bona fide death inducing ligands did not account for death following LTbeta receptor activation indicating that TNF family receptors can trigger a caspase-independent death pathway regardless of the presence of canonical death domains in the receptor. To provide a frame of reference, the phenotype of HT29 death was compared to four other TNF family receptor triggered death events; Fas induced Jurkat cell apoptosis, TNF/zVAD induced L929 fibroblast necrosis, TNF induced death of WEHI 164 fibroblastoid cells and TNF/zVAD induced U937 death. The death of HT29 and U937 cells under these conditions is an intermediate form with both necrotic and apoptotic features. The efficient coupling of TNF receptors to a caspase-independent death event in an epithelial cell suggests an alternative approach to cancer therapy.

Topics: Active Transport, Cell Nucleus; Adenocarcinoma; Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Caspase Inhibitors; Caspases; Colorectal Neoplasms; Enzyme Inhibitors; Epithelial Cells; fas Receptor; Humans; Lymphotoxin beta Receptor; Mice; Microscopy, Electron; Mitochondria; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor; Tumor Cells, Cultured; TWEAK Receptor

Despite the high frequency of prostate cancer, therapeutic options for advanced disease are limited to chemotherapy, radiation or hormonal therapy and eventually fail in all patients. Therefore, alternative approaches need to be developed. We previously reported that FTY720, a metabolite from Isaria sinclarii, is a unique antitumor agent for an androgen-independent prostate cancer cell line and requires caspase-3 activation in apoptosis. In our study, we have evaluated the effect of FTY720 on a family of mitogen-activated protein kinases (MAPKs), focal adhesion kinase (FAK), mitochondrial transmembrane potential, caspase-9 and caspase-8 and analyzed the expression of some cell-cycle regulator proteins in DU145 cells in order to understand the various antitumor effects of FTY720. Apoptosis was quantified by phosphatidylserine exposure. Activation of MAPKs, cleavage of caspase-9 and caspase-8, status of cyclin-dependent kinases (CDKs) and Cip1/p21, a cyclin-dependent kinase inhibitor, were evaluated by Western blot analysis, in addition to FAK and phospho-FAK immunoprecipitation and cell-cycle analysis by FACScan. We found that in DU145 cells, 40 microM FTY720 caused activation of p38 MAPK and the upstream kinase MKK3/MKK6 but not SAPK/JNK. Mitochondrial transmembrane potential, FAK and ERK1/2 were reduced while caspase-9 and caspase-8 were cleaved. The p38-specific inhibitor had no effect on apoptosis induced by FTY720, whereas z-VAD.FMK, a broad-spectrum caspase inhibitor, did not inhibit the p38 MAPK activation. An amount of 20 microM FTY720 resulted in G(1) arrest and a decrease of CDK2 as well as CDK4, whereas it induced Cip1/p21. FTY720 may exert anticarcinogenic effects against prostate cancer cells possibly involving modulation of mitogenic signaling, cell-cycle regulators, induction of G(1) arrest and apoptotic death in DU145 cells.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents; Apoptosis; Caspase Inhibitors; Caspases; Cell Cycle; Cell Cycle Proteins; Cysteine Proteinase Inhibitors; Enzyme Inhibitors; Fingolimod Hydrochloride; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Humans; Kinetics; Male; MAP Kinase Kinase 3; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Mitogens; p38 Mitogen-Activated Protein Kinases; Propylene Glycols; Prostatic Neoplasms; Protein-Tyrosine Kinases; Signal Transduction; Sphingosine; Tumor Cells, Cultured

To investigate the role of the mitochondrial pathway in JTE-522-induced apoptosis and to investigate the relationship between cytochrome C release, caspase activity and loss of mitochondrial membrane potential (Deltapsim).. Cell culture, cell counting, ELISA assay, TUNEL, flow cytometry, Western blot and fluorometric assay were employed to investigate the effect of JTE-522 on cell proliferation and apoptosis in AGS cells and related molecular mechanism.. JTE-522 inhibited the growth of AGS cells and induced the apoptosis. Caspases 8 and 9 were activated during apoptosis as judged by the appearance of cleavage products from procaspase and the caspase activities to cleave specific fluorogenic substrates. To elucidate whether the activation of caspases 8 and 9 was required for the apoptosis induction, we examined the effect of caspase-specific inhibitors on apoptosis. The results showed that caspase inhibitors significantly inhibited the apoptosis induced by JTE-522. In addition, the membrane translocation of Bax and cytosolic release of cytochrome C accompanying with the decrease of the uptake of Rhodamin 123, were detected at an early stage of apoptosis. Furthermore, Bax translocation, cytochrome C release, and caspase 9 activation were blocked by Z-VAD.fmk and Z-IETD-CHO.. The present data indicate a crucial association between activation of caspases 8, 9, cytochrome C release, membrane translocation of Bax, loss of Deltapsim and JTE-522-induced apoptosis in AGS cells.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; bcl-2-Associated X Protein; Benzenesulfonates; Caspase Inhibitors; Caspases; Cyclooxygenase Inhibitors; Cysteine Proteinase Inhibitors; Cytochrome c Group; Enzyme Activation; Humans; In Situ Nick-End Labeling; Membrane Potentials; Mitochondria; Oxazoles; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Stomach Neoplasms; Tumor Cells, Cultured

The molecular basis for the sensitivity of tumor cells to chemopreventive natural food compounds and commonly used chemotherapeutic agents is not well understood, not least because studies are frequently confounded by the diversity among cell lines or rely on experimental protein overexpression. Here we investigated the effects of n-butyrate, a cancer-preventive short-chain fatty acid produced by anaerobic bacteria in the gastrointestinal tract, on the human wild-type p53 and p21 expressing HCT116 colon carcinoma cell line and on HCT116 cells with either p53 or p21 alleles inactivated by homologous recombination. The effects of n-butyrate were then compared with those elicited by cytotoxic drugs and the natural chemopreventive phytoalexin of wine and grapes, resveratrol. We document that physiological concentrations of n-butyrate stimulate p21 expression and induce apoptosis independently of p53, and that the absence of p21 increases apoptosis drastically. The apoptosis is mediated through the mitochondria and is accompanied by mitochondrial proliferation and membrane potential changes. Adriamycin, etoposide, cisplatinum, colcemid and resveratrol induce distinct cellular responses; however, absence of p21 favors apoptosis-induction by adriamycin, etoposide and colcemid. Thus, control of p21 expression may support chemoprevention and certain tumor therapies.

Topics: Adenocarcinoma; Alleles; Amino Acid Chloromethyl Ketones; Anticarcinogenic Agents; Antineoplastic Agents; Apoptosis; Benzothiazoles; Butyrates; Cisplatin; Colonic Neoplasms; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Cysteine Proteinase Inhibitors; Demecolcine; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Fluorouracil; Gene Expression Regulation, Neoplastic; Genes, p53; Humans; Intracellular Membranes; Membrane Potentials; Mitochondria; Neoplasm Proteins; Recombination, Genetic; Resveratrol; Stilbenes; Thiazoles; Toluene; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The antiarrhythmic amiodarone (AM) and its metabolite desethylamiodarone (Des) are known to cause AM-induced pulmonary toxicity, but the mechanisms underlying this disorder remain unclear. We hypothesized that AM might cause AM-induced pulmonary toxicity in part through the induction of apoptosis or necrosis in alveolar epithelial cells (AECs). Two models of type II pneumocytes, the human AEC-derived A549 cell line and primary AECs isolated from adult Wistar rats, were incubated with AM or Des for 20 h. Apoptotic cells were determined by morphological assessment of nuclear fragmentation with propidium iodide on ethanol-fixed cells. Necrotic cells were quantitated by loss of dye exclusion. Both AM and Des caused dose-dependent necrosis starting at 2.5 and 0.1 microg/ml, respectively, in primary rat AECs and at 10 and 5 microg/ml in subconfluent A549 cells (P < 0.05 and P < 0.01, respectively). AM and Des also induced dose-dependent apoptosis beginning at 2.5 microg/ml in the primary AECs (P < 0.05 for both compounds) and at 10 and 5 microg/ml, respectively, in the A549 cell line (P < 0.01). The two compounds also caused significant net cell loss (up to 80% over 20 h of incubation) by either cell type at drug concentrations near or below the therapeutic serum concentration for AM. The cell loss was not due to detachment but was blocked by the broad-spectrum caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone. Furthermore, the angiotensin-converting enzyme inhibitor captopril (500 ng/ml) and the angiotensin-receptor antagonist saralasin (50 microg/ml) significantly inhibited both the induction of apoptosis and net cell loss in response to AM. These results are consistent with recent work from this laboratory demonstrating potent inhibition of apoptosis in human AECs by captopril (Uhal BD, Gidea C, Bargout R, Bifero A, Ibarra-Sunga O, Papp M, Flynn K, and Filippatos G. Am J Physiol Lung Cell Mol Physiol 275: L1013-L1017, 1998). They also suggested that the accumulation of AM and/or its primary metabolite Des in lung tissue may induce cytotoxicity of AECs that might be inhibitable by angiotensin-converting enzyme inhibitors or other antagonists of the renin-angiotensin system.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Amiodarone; Angiotensin-Converting Enzyme Inhibitors; Animals; Apoptosis; Captopril; Cysteine Proteinase Inhibitors; Cytotoxins; Dose-Response Relationship, Drug; Enzyme Inhibitors; Epithelial Cells; Humans; In Vitro Techniques; Lung Neoplasms; Male; Pulmonary Alveoli; Rats; Rats, Wistar; Renin-Angiotensin System; Tumor Cells, Cultured

We investigated the mechanism of mitomycin C (MMC)-induced apoptosis in SNU-16 human gastric adenocarcinoma cells. Caspase-8 and caspase-3 were activated in MMC-treated cells whereas caspase-1 was not activated, and cytochrome c was released from mitochondrial membrane to cytosol suggesting that caspase-9 was activated during the MMC-induced apoptotic process. Protein kinase C (PKC) delta was cleaved to its characteristic 40 kDa fragment in a caspase-3-dependent manner; on the other hand PKC zeta was cleaved to approximately 40 kDa independently of caspase-3 in the drug-induced apoptosis of the cells. Incubation with z-DEVD-fmk and benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD-fmk) almost completely abrogated MMC-induced DNA fragmentation, indicating that activation of these caspases was crucially involved in MMC-induced apoptosis. Activation of caspase-8 in response to Fas triggering by recruitment of caspase-8 to the Fas has also been found, however, MMC did not induce FasL and Fas expression, as evidenced by reverse transcriptase-polymerase chain reaction and Western blotting. Taken together, these findings indicate that MMC-induced apoptosis in SNU-16 cells was mediated by caspase-8, caspase-9, and caspase-3 activation independently of FasL/Fas interactions.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antibiotics, Antineoplastic; Apoptosis; Caspase 3; Caspase 8; Caspase 9; Caspase Inhibitors; Caspases; Cell Death; Cysteine Proteinase Inhibitors; Enzyme Activation; fas Receptor; Humans; Mitomycin; Oligopeptides; Stomach Neoplasms; Time Factors; Tumor Cells, Cultured

Caspase-8 plays an essential role in apoptosis triggered by death receptors. Through the cleavage of Bid, a proapoptotic Bcl-2 member, it further activates the mitochondrial cytochrome c/Apaf-1 pathway. Because caspase-8 can be processed also by anticancer drugs independently of death receptors, we investigated its exact role and order in the caspase cascade. We show that in Jurkat cells either deficient for caspase-8 or overexpressing its inhibitor c-FLIP apoptosis mediated by CD95, but not by anticancer drugs was inhibited. In the absence of active caspase-8, anticancer drugs still induced the processing of caspase-9, -3 and Bid, indicating that Bid cleavage does not require caspase-8. Overexpression of Bcl-x(L) prevented the processing of caspase-8 as well as caspase-9, -6 and Bid in response to drugs, but was less effective in CD95-induced apoptosis. Similar responses were observed by overexpression of a dominant-negative caspase-9 mutant. To further determine the order of caspase-8 activation, we employed MCF7 cells lacking caspase-3. In contrast to caspase-9 that was cleaved in these cells, anticancer drugs induced caspase-8 activation only in caspase-3 transfected MCF7 cells. Thus, our data indicate that, unlike its proximal role in receptor signaling, in the mitochondrial pathway caspase-8 rather functions as an amplifying executioner caspase.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents; Apoptosis; bcl-X Protein; BH3 Interacting Domain Death Agonist Protein; Breast Neoplasms; Carrier Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 3; Caspase 8; Caspase 9; Caspases; Cysteine Proteinase Inhibitors; Enzyme Activation; Enzyme Precursors; Etoposide; fas Receptor; Humans; Intracellular Signaling Peptides and Proteins; Jurkat Cells; Mitochondria; Mitomycin; Neoplasm Proteins; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Tumor Cells, Cultured

The novel synthetic retinoid 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) has been shown to induce apoptosis in various tumor cell lines including human non-small cell lung carcinoma (NSCLC) cells, which are resistant to the natural all-trans retinoic acid and to many synthetic receptor-selective retinoids. Although the mechanism of this effect was not elucidated, it was found to be independent of nuclear retinoid receptors. In the present study, we analysed the mechanisms by which CD437 induces apoptosis in two human NSCLC cell lines: H460 with wild-type p53 and H1792 with mutant p53. Both cell lines underwent apoptosis after exposure to CD437, although the cell line with wild-type p53 (H460) was more sensitive to the induction of apoptosis. CD437 increased the activity of caspase in both cell lines, however, the effect was much more pronounced in the H460 cells. The caspase inhibitors (Z-DEVD-FMK and Z-VAD-FMK) suppressed CD437-induced CPP32-like caspase activation and apoptosis in both cell lines. CD437 induced the expression of the p53 gene and its target genes, p21, Bax, and Killer/DR5, only in the H460 cells. These results suggest that CD437-induced apoptosis is more extensive in NSCLC cells that express wild-type p53, possibly due to the involvement of the p53 regulated genes Killer/DR5, and Bax although CD437 can also induce apoptosis by means of a p53-independent mechanism. Both pathways of CD437-induced apoptosis appear to involve activation of CPP32-like caspase.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Carcinoma, Large Cell; Carcinoma, Non-Small-Cell Lung; Caspase 3; Caspase Inhibitors; Cell Cycle; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Cysteine Proteinase Inhibitors; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Humans; Lung Neoplasms; Neoplasm Proteins; Oligopeptides; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Retinoids; Tumor Cells, Cultured

In this study we investigated the signalling requirements for TNF-induced cytotoxicity modulated by the methyltransferase inhibitor S-adenosyl-L-homocysteine (AdoHcy) using the TNF-sensitive human breast carcinoma MCF7 cells and its established TNF-resistant clones (R-A1 and clone 1001). Our data indicate that inhibition of methylation reactions by adenosine plus homocysteine, which are known to condense within cells to AdoHcy, markedly potentiated TNF-induced cytotoxicity in MCF7 cells and rendered related TNF-resistant variants, TNF-sensitive by a mechanism independent from the ceramide pathway. We demonstrated that the dominant-negative derivative of FADD (FADD-DN) blocked methylation inhibition/TNF-induced cell death. Moreover, TNF-mediated cytotoxicity modulated by AdoHcy was blocked by the ICE-inhibiting peptide z-VAD-fmk, suggesting that an ICE-like protease is required for the methylation inhibition/TNF-inducible death pathway. In conclusion, these results suggest that the methyltransferase inhibitor AdoHcy potentiates TNF-induced cytotoxicity in MCF7 cells and renders TNF-resistant MCF7 clones, TNF-sensitive via the ceramide independent pathway and that FADD and the ICE-like protease are likely necessary components in transducing methylation inhibition/TNF signals for cell death.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Apoptosis; Arabidopsis Proteins; Breast Neoplasms; Caspase Inhibitors; Ceramides; Cysteine Proteinase Inhibitors; DNA (Cytosine-5-)-Methyltransferases; DNA Methylation; Drug Resistance; Fatty Acid Desaturases; Female; Humans; Recombinant Fusion Proteins; S-Adenosylhomocysteine; Tumor Necrosis Factor-alpha

Recent works from this laboratory demonstrated potent inhibition of Fas-induced apoptosis in alveolar epithelial cells (AECs) by the angiotensin-converting enzyme (ACE) inhibitor captopril [B. D. Uhal, C. Gidea, R. Bargout, A. Bifero, O. Ibarra-Sunga, M. Papp, K. Flynn, and G. Filippatos. Am. J. Physiol. 275 (Lung Cell. Mol. Physiol. 19): L1013-L1017, 1998] and induction of dose-dependent apoptosis in AECs by purified angiotensin (ANG) II [R. Wang, A. Zagariya, O. Ibarra-Sunga, C. Gidea, E. Ang, S. Deshmukh, G. Chaudhary, J. Baraboutis, G. Filippatos and B. D. Uhal. Am. J. Physiol. 276 (Lung Cell. Mol. Physiol. 20): L885-L889, 1999]. These findings led us to hypothesize that the synthesis and binding of ANG II to its receptor might be involved in the induction of AEC apoptosis by Fas. Apoptosis was induced in the AEC-derived human lung carcinoma cell line A549 or in primary AECs isolated from adult rats with receptor-activating anti-Fas antibodies or purified recombinant Fas ligand, respectively. Apoptosis in response to either Fas activator was inhibited in a dose-dependent manner by the nonthiol ACE inhibitor lisinopril or the nonselective ANG II receptor antagonist saralasin, with maximal inhibitions of 82 and 93% at doses of 0.5 and 5 microg/ml, respectively. In both cell types, activation of Fas caused a significant increase in the abundance of mRNA for angiotensinogen (ANGEN) that was unaffected by saralasin. Transfection with antisense oligonucleotides against ANGEN mRNA inhibited the subsequent induction of Fas-stimulated apoptosis by 70% in A549 cells and 87% in primary AECs (both P < 0.01). Activation of Fas increased the concentration of ANG II in the serum-free extracellular medium 3-fold in primary AECs and 10-fold in A549 cells. Apoptosis in response to either Fas activator was completely abrogated by neutralizing antibodies specific for ANG II (P < 0.01), but isotype-matched nonimmune immunoglobulins had no significant effect. These data indicate that the induction of AEC apoptosis by Fas requires a functional renin-angiotensin system in the target cell. They also suggest that therapeutic control of AEC apoptosis is feasible through pharmacological manipulation of the local renin-angiotensin system.

Topics: Adenocarcinoma; Amino Acid Chloromethyl Ketones; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Antibodies; Antisense Elements (Genetics); Apoptosis; Cysteine Proteinase Inhibitors; Enzyme-Linked Immunosorbent Assay; Fas Ligand Protein; fas Receptor; Fibrosis; Gene Expression; Humans; Lisinopril; Lung Neoplasms; Male; Membrane Glycoproteins; Neutralization Tests; Peptidyl-Dipeptidase A; Pulmonary Alveoli; Rats; Rats, Wistar; Receptors, Angiotensin; Renin-Angiotensin System; RNA, Messenger; Signal Transduction; Transfection; Tumor Cells, Cultured