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Query: UMLS:C0242379 (lung cancer)
 71,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied the subcellular localization and expression levels of proteasomes during apoptosis in a lung cancer cell line. Apoptosis was induced by exposing the cells to 200 microM olomoucine, a specific cyclin-dependent kinase inhibitor. The morphological changes characteristic for apoptotic cells were visible: the cells reduced in size, the chromatin condensed and the membranes became convoluted. As the process continued, the nuclei became fragmented, and the cells broke up into cytoplasmic vesicles and apoptotic bodies. Immunocytochemically, apoptotic cells were detected by the ability to bind annexin V at their surface. During the initial stages of apoptosis, proteasomes were present in the nucleus as well as in the cytoplasm. Upon increased chromatin condensation, nuclear proteasomes were found predominantly surrounding the chromatin, while the chromatin itself remained devoid of staining. That the proteasomes persisted relatively long in the apoptotic cells was shown by immunoblotting of non-denaturing gels, which indicated that both 20S and 26S proteasomes were present in apoptotic cells. In immunofluoresence microscopy the proteasome fluorescence intensity of apoptotic cells seemed higher than that of non-apoptotic cells. These differences in intensity were even more pronounced after Triton X-100 extraction. Flow cytometry revealed that the absolute levels of proteasome staining in cells were decreased after Triton X-100 extraction. However, no differences in staining levels were detected between apoptotic and non-apoptotic cells. A relative increase of proteasome concentration through cell shrinkage or a concentration in certain cell compartments may be the origin of the apparently increased signal that was seen in immunofluorescence microscopy. Furthermore, proteasomes were clearly detectable in the apoptotic bodies and cytoplasmic vesicles at the time immunocytochemical reactivity for cytokeratins and lamins had diminished to a large extent. Immunoblotting of denaturing polyacrylamide gels confirmed the results obtained by flow cytometry. The proteasome content was retained only partially in the cells after Triton X-100 extraction, while the intermediate filaments were not detectable anymore in the apoptotic cells.
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PMID:Subcellular localization of proteasomes in apoptotic lung tumor cells and persistence as compared to intermediate filaments. 883 9

During apoptosis, one of the first membrane changes that can be detected is exposure of phosphatidylserine residues at the outer plasma membrane leaflet, while early apoptosis is also accompanied by changes in the cytoskeletal organization. In this study we investigated the relationship between these two phenomena during olomoucine- and roscovitin-induced apoptosis in human lung cancer and neuroblastoma cell lines. Loss of membrane asymmetry was detected by biotin-labeled or FITC-labeled annexin V binding to negatively charged phosphatidylserine, while cytoskeletal components were visualized by immunocytochemistry. The apoptotic, annexin V-positive, cells were analyzed by flow cytometry, confocal scanning laser microscopy, and Western blotting. We report that cytokeratin and vimentin aggregation in early apoptosis occurs simultaneously with phosphatidylserine exposure and chromatin condensation. In contrast to these intermediate filament proteins, which were disassembled and proteolytically cleaved in early apoptosis, microfilaments and microtubuli were not proteolytically degraded but were found to be present as aggregated filaments in the apoptotic bodies. We also show that loss of membrane asymmetry and cytokeratin aggregation are independent processes, since N-ethylmaleimide-induced phosphatidylserine exposure does not cause cytokeratin disassembly. Vice versa, phorbol 12-myristate 13-acetate-induced cytokeratin filament aggregation does not result in phosphatidylserine exposure.
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PMID:Plasma membrane alterations and cytoskeletal changes in apoptosis. 929 67

In order to study the biological activities of tea preparations and purified tea polyphenols, their growth inhibitory effects were investigated using four human cancer cell lines. Growth inhibition was measured by [3H]thymidine incorporation after 48 h of treatment. The green tea catechins (-)-epigallocatechin-3-gallate (EGCG) and (-)-epigallocatechin (EGC) displayed strong growth inhibitory effects against lung tumor cell lines H661 and H1299, with estimated IC50 values of 22 microM, but were less effective against lung cancer cell line H441 and colon cancer cell line HT-29 with IC50 values 2- to 3-fold higher. (-)-Epicatechin-3-gallate, had lower activities, and (-)-epicatechin was even less effective. Preparations of green tea polyphenols and theaflavins had higher activities than extracts of green tea and decaffeinated green tea. The results suggest that the growth inhibitory activity of tea extracts is caused by the activities of different tea polyphenols. Exposure of H661 cells to 30 microM EGCG, EGC or theaflavins for 24 h led to the induction of apoptosis as determined by an annexin V apoptosis assay, showing apoptosis indices of 23, 26 and 8%, respectively; with 100 microM of these compounds, the apoptosis indices were 82, 76 and 78%, respectively. Incubation of H661 cells with EGCG also induced a dose-dependent formation of H2O2. Addition of H2O2 to H661 cells caused apoptosis in a manner similar to that caused by EGCG. The EGCG-induced apoptosis in H661 cells was completely inhibited by exogenously added catalase (50 units/ml). These results suggest that tea polyphenol-induced production of H2O2 may mediate apoptosis and that this may contribute to the growth inhibitory activities of tea polyphenols in vitro.
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PMID:Inhibition of growth and induction of apoptosis in human cancer cell lines by tea polyphenols. 960 Mar 45

Expression levels of gangliosides and glycosyltransferase genes responsible for their syntheses in human lung cancer cell lines and a normal bronchial epithelial cell line were analyzed. Both non-small cell lung cancers and small cell lung cancers (SCLCs) mainly expressed G(M2) and G(M1), whereas only SCLCs expressed b-series gangliosides, such as G(D2), G(D1b), and G(T1b). Accordingly, many SCLC cell lines showed up-regulation of the G(D3) synthase gene. Consequently, we introduced G(D3) synthase cDNA into a SCLC line with low expression of b-series gangliosides and analyzed the effects of newly expressed gangliosides on tumor phenotypes. The transfectant cells expressing high levels of G(D2) and G(D3) exhibited markedly increased growth rates and strongly enhanced invasion activities. Addition of anti-G(D2) monoclonal antibodies into the culture medium of these cells resulted in the marked growth suppression of G(D2)-expressing cell lines with reduced activation levels of mitogen-activated protein kinases but not of nonexpressants, suggesting that G(D2) plays important roles in cell proliferation. Moreover, G(D2)-expressing cells treated with anti-G(D2) antibodies showed features of apoptotic cell death at 30 min after addition of antibodies, i.e., shrinkage of cytoplasm, binding of Annexin V, and staining with propidium iodide, followed by DNA fragmentation. This G(D2)-mediated apoptosis was associated with caspase-3 activation and partly inhibited by a caspase inhibitor, z-Val-Ala-Asp-fluoromethyl ketone. The finding that anti-G(D2) antibodies suppressed the cell growth and induced apoptosis of SCLC cells strongly suggested the usefulness of G(D2) as a target for the therapy of disastrous cancer, although the precise mechanisms for apoptosis remain to be clarified.
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PMID:Ganglioside G(D2) in small cell lung cancer cell lines: enhancement of cell proliferation and mediation of apoptosis. 1135 51

Our objective was to compare different methods for studying programmed cell death in adherent H460 non-small lung cancer cells of moderate clonogenic radiosensitivity. The major effect of gamma-radiation was found to be the release of cells from the substratum. The different methods gave complementary and unexpected information: a) with the TUNEL method, a few non-apoptotic cells were found in the culture medium; b) with the flow cytometry after propidium iodide labeling, some hypodiploid cells which remained attached to the substratum were apoptotic, as demonstrated by the effect of a caspase inhibitor; c) with the annexin V labeling, the detached cells were demonstrated either necrotic or very late apoptotic; d) the mitochondria transmembrane potential (deltapsim), measurements demonstrated that the mitochondria were implicated in cell death induced by gamma-radiation. These data illustrate the need to use several complementary methods in the study of apoptosis in adherent cells exposed to gamma-radiation.
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PMID:Comparison of methods used to study cell death in an adherent tumoral cell line with moderate clonogenic radiosensitivity. 1184 80

We identified a novel mouse gene, mRTVP-1, as a p53 target gene using differential display PCR and extensive promoter analysis. The mRTVP-1 protein has 255 amino acids and differs from the human RTVP-1 (hRTVP-1) protein by two short in-frame deletions of two and nine amino acids. RTVP-1 mRNA was induced in multiple cancer cell lines by adenovirus-mediated delivery of p53 and by gamma irradiation or doxorubicin both in the presence and in the absence of endogenous p53. Analysis of RTVP-1 expression in nontransformed and transformed cells further supported p53-independent gene regulation. Using luciferase reporter and electrophoretic mobility shift assays we identified a p53 binding site within intron 1 of the mRTVP-1 gene. Overexpression of mRTVP-1 or hRTVP-1 induced apoptosis in multiple cancer cell lines including prostate cancer cell lines 148-1PA, 178-2BMA, PC-3, TSU-Pr1, and LNCaP, a human lung cancer cell line, H1299, and two isogenic human colon cancer cell lines, HCT116 p53(+/+) and HCT116 p53(-/-), as demonstrated by annexin V positivity, phase-contrast microscopy, and in selected cases 4',6'-diamidino-2-phenylindole staining and DNA fragmentation. Deletion of the signal peptide from the N terminus of RTVP-1 reduced its apoptotic activities, suggesting that a secreted and soluble form of RTVP-1 may mediate, in part, its proapoptotic activities.
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PMID:mRTVP-1, a novel p53 target gene with proapoptotic activities. 1197 68

Many therapeutically active anticancer treatments exert their effect by the induction of apoptosis and necrosis. Serial biopsies in breast cancer patients have suggested that response to therapy correlates with early posttreatment increases in tumor apoptotic index. Radiolabeled technetium Tc 99m-recombinant human (rh) annexin V provides a noninvasive technique for imaging treatment-induced cell death. Annexin V is a naturally occurring human protein that binds avidly to membrane-associated phosphatidylserine (PS). PS is normally found only on the inner leaflet of the cell membrane double layer, but it is actively transported to the outer layer as an early event in apoptosis and becomes available for annexin binding. Annexin also gains access to PS as a result of the membrane fragmentation associated with necrosis. In vitro studies of apoptosis using fluorescein annexin have shown good correlation with assessments of apoptosis documented by nuclear DNA degradation and caspase activation. In vivo localization of intravenously administered Tc 99m-annexin V has been demonstrated in numerous preclinical models of apoptosis, including anti-Fas-mediated hepatic apoptosis, rejection of allogeneic heterotopic cardiac allografts, cyclophosphamide treatment of murine lymphoma, cyclophosphamide-induced apoptosis in bone marrow, and leukocyte apoptosis associated with abscess formation. Scintigraphic studies in humans using Tc 99m-rh annexin V have demonstrated the feasibility of imaging cell death in acute myocardial infarction, in tumors with a high apoptotic index, and in response to anti-tumor chemotherapy of non-small cell lung cancer, small-cell lung cancer, breast cancer, lymphoma, and sarcoma. Increased localization of Tc 99m-rh annexin V within 1 to 3 days of chemotherapy has been noted in some, but not all, subjects with these tumors. To date, most subjects showing increased Tc 99m-rh annexin V uptake after the first course of chemotherapy have shown objective clinical responses. A single site study in 15 subjects with 1-year follow-up has suggested that increased posttreatment Tc 99m-rh annexin uptake is associated with improved time to progression of disease and survival time. In vivo imaging of cell death may have the potential to improve the treatment of cancer patients by allowing rapid, objective, patient-by-patient assessment of the efficacy of tumor cell killing.
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PMID:Monitoring apoptosis in real time. 1199 52

The synthetic retinoid fenretinide [N-(4-hydroxyphenyl)retinamide, 4-HPR] has demonstrated growth inhibition and induction of apoptosis of various malignant cells, including lung cancer cell lines. 4-HPR is now being investigated in several clinical trials. In our study, we show that 4-HPR inhibits growth on a broad panel of lung cancer cell lines (12/12 small cell lung cancer and 9/12 nonsmall cell lung cancer cell lines), including cell lines unresponsive to all-trans-retinoic acid (ATRA). 4-HPR revealed a higher potency than ATRA in inhibiting cell growth with IC(50) values ranging from 3.3-8.5 microM. Furthermore, 4-HPR induces apoptosis in lung cancer cell lines as proven by TUNEL and annexin V assay. Despite this, we observed stimulation of growth in 2 SCLC cell lines at 1 microM 4-HPR. In advance to the clinical application of 4-HPR, we demonstrate that growth inhibition is reversible after removal of 4-HPR and that long-term application is necessary. Through long-term stimulation with 4-HPR, we cultivated 3 resistant cell lines that were still inhibited by 4-HPR after several weeks, however, exhibited almost no apoptosis. These cell lines exhibited morphologic changes, which in the case of the SCLC cell lines suggested differentiation. Our data show that 4-HPR inhibits growth in lung cancer cell lines by varying mechanisms including (i) cytostasis, (ii) apoptosis and (iii) presumably, differentiation. In contrast, the observed growth stimulation, reversibility of growth inhibition and development of resistance to apoptosis make successful cancer therapy uncertain and may limit clinical application of 4-HPR in lung cancer patients, although its inhibitory effects last over several weeks.
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PMID:Is growth inhibition and induction of apoptosis in lung cancer cell lines by fenretinide [N-(4-hydroxyphenyl)retinamide] sufficient for cancer therapy? 1212

Uteroglobin is a secretory protein synthesized by most epithelia, including the respiratory tract. It has strong anti-inflammatory properties that appear to be related to the inhibition of phospholipase A2. Recent experimental evidence indicates that uteroglobin has an inhibitory effect on the proliferation and invasion of cancer cells. We investigated the effects of the adenovirus-uteroglobin (ad-UG) transduction on the growth of lung cancer cell lines, which did not express the uteroglobin gene. Upon transduction of ad-UG, the rate of cell growth and the ability to produce colonies in soft agar were evaluated. Cell cycle analysis, Western blot for cell cycle-related proteins and annexin V staining for apoptosis were carried out to see if they were associated with the changes in cell growth. All the tested lung cancer cell lines did not express the uteroglobin gene. The growth rates, and colony-forming ability of transformed cells, were significantly inhibited by the induction of uteroglobin gene expression. The DNA histogram showed that the cell fraction of the G2/M phase was increased, and this G2/M phase arrest was related to a decrease of cdk1 and cyclin A. However, a fraction of apoptotic cells were same as the control. From these results, uteroglobin is thought to have an inhibitory effect on the growth of lung cancer cells. This suggests a potential role for uteroglobin in gene therapy for lung cancer.
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PMID:Inhibitory effect of adenovirus-uteroglobin transduction on the growth of lung cancer cell lines. 1267 1

In the past 10 years, FDG-PET has become an important imaging modality in NSCLC. Its indication in the assessment of lung nodules and staging is based on large prospective experience, further supported by some meta-analyses. This evidence has important consequences for patient management, which recently was proved in a randomized trial that showed a reduction in the number of futile thoracotomies by preoperative PET. The use of FDG-PET could become more widespread when commercial isotope distributors are able to deliver FDG so that an on-site cyclotron is no longer a prerequisite. FDG has a half-life of 110 minutes, so a practical distribution radius of 200 km should be feasible. Current indications for PET in the staging of newly diagnosed NSCLC are mainly the patients who are considered to be candidates for radical treatment. The technique does not have a clinical indication in other patients--for example, when metastatic lymph nodes are detected at clinical examination, when a simple ultrasound study already points to diffuse hepatic metastases, or in cases of poor performance status. PET also has prognostic value; it can be used for the evaluation of response or restaging after radiotherapy or chemotherapy and for early detection of relapse. The combination of CT and PET improves radiotherapy planning and it is to be expected that combined CT-PET-guided planning devices will further refine three-dimensional conformal radiotherapy. Finally, a whole new field of application of PET in molecular biology using new radiopharmaceutics is in development. FDG, with its possibility to study tumor glucose metabolism, has paved the way for PET in clinical oncology. It is hoped that PET examinations with new molecular tracers will allow ever better specificity and become sufficiently reliable and manageable to evaluate receptors, transport proteins, and intracellular enzymes so that very early response monitoring during chemotherapy or radiotherapy, evaluation of novel molecular-targeted lung cancer therapies, or even gene therapy becomes possible. New tracers that have showed their promise in early clinical studies include 18F-fluorothymidine (a proliferation marker that might give better specificity in the assessment of solitary pulmonary nodules or better accuracy in the evaluation of early response), (99m)Tc-Annexin V (Apomate; an apoptosis-imaging agent that could be correlated with overall and progression-free survival in phase I data), or 18F-fluoromisonidazole (which can be used to quantify regional hypoxia in human tumors with PET).
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PMID:Positron emission tomography in the management of non-small cell lung cancer. 1500 93


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