Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin 13 receptor (IL-13R)-targeted cytotoxin, IL13-PE38QQR, composed of IL-13 and a mutated form of Pseudomonas exotoxin (PE), is found to be highly and specifically cytotoxic to human solid cancer cell lines. However, the mechanism of tumor cell death mediated by IL-13 toxin is still not known. To elucidate the mechanism, we utilized four head and neck cancer cell lines (SCC-25, HN12, KCCT873, and YCUM911), which express high levels of IL-13R, and IL-13 toxin is highly cytotoxic to these cells. We observed chromatin condensation and DNA fragmentation, indicating apoptotic cell death, after treatment with IL-13 toxin, as determined by bis-benzimide staining and DNA ladder assays. However, IL-13 did not induce cell death. Flow cytometric analysis suggested that these cancer cell lines increased the sub-G1/G0 phase DNA population in a dose- and time-dependent manner (ranged between 10 and 30%) after treatment with IL-13 toxin. By Western blot analysis, cleavage of caspase-3 and PARP was observed after treatment with a high concentration of IL-13 toxin, also suggesting apoptotic cell death. In addition, the results of immunofluorescence and RT-PCR assays showed that the apoptosis-regulator, Bcl-2 was downregulated after treatment with IL-13 toxin, while Bax was upregulated. Moreover, significant nitrite production was detected in the HN12 cell line after treatment with IL-13 toxin for 48--96 h. Taken together, our results suggest that IL-13 toxin-induced cytotoxicity is at least partially mediated by the apoptosis and nitric oxide pathways. This information may be useful in developing specific approaches where apoptotic bodies from tumor cells may be used to pulse antigen-presenting cells for immunotherapy of cancer.
 ...
PMID:Apoptotic pathways of cell death induced by an interleukin-13 receptor-targeted recombinant cytotoxin in head and neck cancer cells. 1186 21

Exposure of pulmonary airways to environmental toxins and allergens may cause proliferation of airway epithelial cells and mucous cell metaplasia (MCM); however, it is unclear to what extent proliferating cells differentiate into mucus-storing cells and contribute to MCM. Our previous studies demonstrated that Bcl-2, an inhibitor of apoptosis with cell cycle regulatory functions, is expressed in metaplastic mucous cells. The purpose of the present study was to investigate the number of metaplastic mucous cells that are derived from proliferating epithelial cells and whether Bcl-2 has a role in cell cycle entry in these cells. Rats were intratracheally instilled with 100 microg of LPS from Pseudomonas aeruginosa in 500 microl of saline, and proliferating airway cells were labeled with bromodeoxyuridine (BrdU) by implanting a subcutaneous osmotic pump 24 h before instillation. The volume of stored mucosubstance and the number of mucous cells were increased 10- and 3-fold, respectively, from 24-48 h after instillation. The number of total epithelial cells per millimeter of basal lamina increased, and the number of serous cells per millimeter of basal lamina decreased during this time. Approximately 50% of Alcian blue-periodic acid Schiff-stained mucous cells were labeled with BrdU at 48 h after instillation, suggesting that one-half of the secretory cells were derived from proliferating cells. Furthermore, 50% of the Bcl-2-positive mucous cells were BrdU negative and therefore derived from nonproliferating, preexisting cells. Our findings demonstrate that preexisting and proliferating cells differentiate into mucous cells and compose LPS-induced metaplasia and that Bcl-2 does not have cell cycle regulatory function in these cells.
 ...
PMID:DNA synthesis and Bcl-2 expression during development of mucous cell metaplasia in airway epithelium of rats exposed to LPS. 1452 29

Gut epithelial apoptosis is increased in human studies and animal models of noninfectious inflammation and sepsis. Elevated intestinal cell death appears to be physiologically significant in sepsis. Previous studies demonstrate that overexpression of the antiapoptotic protein Bcl-2 in the gut epithelium of transgenic mice is associated with improved survival from Pseudomonas aeruginosa pneumonia and cecal ligation and puncture. The functional significance of elevated gut apoptosis in noninfectious inflammation has not been examined. We hypothesized that intestinal apoptosis would be detrimental to survival in noninfectious critical illness. To address this issue, acute lung injury (ALI) was induced with intratracheal injection of lipopolysaccharide (LPS, 800 microg) in wild-type (WT) FVB/N mice and transgenic mice that overexpress Bcl-2 in their intestinal epithelium. Guts were harvested at 12, 24, 48, and 72 h and assessed for apoptosis by both hematoxylin and eosin and active caspase-3 staining in 100 contiguous crypts. ALI increased gut epithelial apoptosis 12 h after LPS instillation compared with shams (P < 0.01), whereas overexpression of Bcl-2 decreased intestinal apoptosis compared with WT animals with ALI when assayed by active caspase-3 (P < 0.05). Plasma levels of tumor necrosis factor alpha, interleukin (IL)-6, and IL-10 were similar between WT and transgenic animals with ALI, both of which had elevated IL-10 levels at 12 h and elevated IL-6 levels at 24 h compared with sham animals. In a separate experiment, transgenic and WT animals with ALI were followed for mortality to determine whether gut overexpression of Bcl-2 conferred a survival advantage. Survival at 10 days was 73% in WT animals (n = 33) and 65% in Bcl-2 animals (n = 23, P = ns). These results indicate that while gut epithelial apoptosis is elevated in multiple models of critical illness, prevention of intestinal cell death by overexpression of Bcl-2 is associated with a disparate survival effect between sepsis and noninfectious inflammation.
 ...
PMID:Bcl-2 inhibits gut epithelial apoptosis induced by acute lung injury in mice but has no effect on survival. 1456 Jan 8

In past studies, we showed that T cells transduced with retroviral diphtheria immunotoxin (IT) target genes could serve as vehicles for delivering IT to tumors in vivo. We took advantage of the observation that antigen-specific T cells are able to penetrate tumors to design an approach delivering combined cellular and humoral therapy directly to the tumor site. To improve tumor specificity, we selected interleukin (IL)-3 as a ligand because its receptor is selectively overexpressed on myeloid leukemia progenitors. Because Bcl-2 family proteins show structural similarity to diphtheria toxin (DT), we constructed a unique retroviral IT using Bax, a proapoptotic member of the Bcl-2 family, in place of DT. Bax was chosen because several studies showed that its transduction induces lethal apoptosis in different cancers. The retroviral construct for gene therapy included IL-3 positioned downstream of its 80 amino acid leader, and permitted cotranslational protein synthesis of hybrid IL-3/human Bax fusion protein. Other vectors were constructed with IL-3 fused to DT or Pseudomonas exotoxin. Retroviral vectors were used to transiently transduce C8, a CD4(+) T cell clone that specifically recognized FBL-3, a lethal myeloid leukemia. Supernatants collected from transduced cells showed proapoptotic activity and selectively inhibited FBL-3 cells in vitro. Intraperitoneal injection of transduced but not nontransduced C8 into mice with subcutaneous tumors or systemic cancer significantly inhibited tumor growth. These results indicate that retroviral IT made with IL-3 and various toxic proteins may be useful in patients with acute myelogenous leukemia (AML). Furthermore, the Bax construct may be particularly useful as a nonimmunogenic substitute for bacterial toxins in retIT.
 ...
PMID:Retroviral immunotoxin gene therapy of leukemia in mice using leukemia-specific T cells transduced with an interleukin-3/Bax fusion protein gene. 1467 Jan 29

Heme oxygenase (HO) is well known as the rate-limiting enzyme in the oxidative degradation of heme to biliverdin, carbon monoxide (CO), and iron. Based on recent evidence that overexpression of HO-1 confers protection against various types of cell and tissue injury by regulating apoptotic cell death or cytokine expression profiles, the present study was performed to examine whether the transfer of exogenous HO-1 cDNA in the lung would provide therapeutic effect in a murine model of lung inflammation induced by Pseudomonas aeruginosa. HO-1 overexpression clearly attenuated neutrophil influx and decreased numbers of apoptotic bronchial epithelial cells. Interestingly, the overexpression of Bcl-2, a known antiapoptotic factor, was observed and thought to be the mechanism that inhibits bronchial epithelial cellular apoptosis. It is thus suggested that HO-1 overexpression is useful for treating P. aeruginosa-associated lung inflammation by attenuating neutrophil influx and apoptotic cell death.
 ...
PMID:Pseudomonas aeruginosa-induced neutrophilic lung inflammation is attenuated by adenovirus-mediated transfer of the heme oxygenase 1 cDNA in mice. 1501 36

The death of individual cells is a frequent and physiological event in the mammalian immune system and most often occurs by apoptosis. It is becoming increasingly clear that cell death is also induced during bacterial infections. Here we report that, in addition to the apoptotic form already established, a necrosis-like form of cell death is induced by pyogenic bacteria (Enterobacteriaceae, Pseudomonas, enterococci) in mouse macrophages. Necrosis could be separated from apoptosis as it did not require phagocytosis of bacteria and occurred when apoptosis was inhibited by caspase blockade or by Bcl-2. Furthermore, ligands that stimulate Toll-like receptors were also found to have the capacity to induce necrosis. Strikingly, this form of cell death was sufficient for the uptake of dead cells by either mouse bone marrow-derived DC or a cell line derived from DC, possibly by virtue of the externalization of phosphatidylserine. Since the loading with bacteria-carrying cells is likely to impact on DC function, this form of necrosis may have a previously unsuspected role in the development of an immune response.
 ...
PMID:Necrosis-like cell death induced by bacteria in mouse macrophages. 1511 80

Pseudomonas exotoxin (PE)-containing immunotoxins (ITs) act by arresting protein synthesis and promoting apoptosis, but the mechanisms of the induced apoptosis and the relationship to protein synthesis inhibition is not well elucidated. We studied these effects in MA-11 human breast cancer cells treated with 425.3PE, an unmodified PE covalently linked to the 425.3 antibody, which targets the EGF receptor. This IT induced efficient inhibition of protein synthesis with simultaneous induction of apoptosis. Thus, treatment of cells with 10 ng/ml of IT for 5 hr caused 85% inhibition of protein synthesis in parallel with caspase-3, -8 and -9 activation and PARP inactivation. Even after 72 hr of IT treatment, preincubation with the broad-spectrum caspase inhibitor z-VAD-FMK caused a significant increase in cell survival without affecting IT-induced protein synthesis inhibition. Interestingly, a combination of z-VAD-FMK and the cathepsin B/L inhibitor z-FA-FMK prevented completely IT-induced cell death in MA-11 cells after 24 hr, indicating that cathepsin activation may be important for optimal induction of IT-induced cell death. IT treatment caused after 2.5 hr a significant decrease in the level of the antiapoptotic protein Mcl-1 but not of Bcl-2 and Bcl-XL. Furthermore, Mcl-1 expression was not sensitive to caspase inhibitors but was totally prevented by the lactacystin proteasome inhibitor, suggesting that IT-induced apoptosis may be triggered by a reduction in the Mcl-1 level. Mitochondrial membrane potential (DeltaPsi mito) decreased concurrently with caspase activation, showing the involvement of DeltaPsi mito as a regulator of IT-induced apoptosis. Our results demonstrate that 425.3PE-mediated cell death involves simultaneous induction of apoptosis and protein synthesis inhibition in MA-11 cells, thus contributing to an understanding of the mechanisms involved in IT-induced apoptosis.
 ...
PMID:Downregulation of the antiapoptotic MCL-1 protein and apoptosis in MA-11 breast cancer cells induced by an anti-epidermal growth factor receptor-Pseudomonas exotoxin a immunotoxin. 1538 75

As a low molecular weight redox protein elaborated from the pathogenic bacteria Pseudomonas aeruginosa, azurin is one of representative bacterial products applied in the treatment of tumour. We found that the growth of U2OS cells was significantly inhibited by azurin in a dose-dependent manner with the IC(50) value of 114.54+/-7.65 mgl(-1). But the growth of MG63 cells or L02 cells was almost not inhibited by azurin (P<0.05). Moreover, when treated with azurin, U2OS cells showed typical apoptotic morphological features observed by fluorescent microscopy (AO and Hoechst 33258) and transmission electron microscopy. Typical DNA "ladder" bands were also observed. The apoptosis rate was 35.8% tested by fluorescence-activated cell sorter (Annexin-V-FITC(+)/PI(-)) and the cell-cycle arrested in G(1) phase. But no apoptotic features were observed in control cells. The down-regulation of Bcl-2 (an inhibitor of apoptosis) were detected in U2OS cells when azurin was added for 24h. In contrast, the level of Bax and caspase-3 were significantly up-regulated. So we concluded that azurin could selectively induce apoptosis of human osteosarcoma U2OS cells and the induction of apoptosis by azurin was closely associated with down-regulation of Bcl-2, up-regulation of Bax and activation of caspase-3.
 ...
PMID:Bacterial redox protein azurin induce apoptosis in human osteosarcoma U2OS cells. 1602 99

This report reviews and integrates our recent clinical and laboratory findings of the effects of daily (DW)/overnight (EW) contact lens wear on corneal epithelial homeostasis. In a prospective, double-masked human clinical study, three lens types (high and hyper Dk/t soft; hyper Dk/t RGP) were used to assess the effects of daily and overnight lens wear on corneal epithelial thickness, cell surface size, Pseudomonas aeruginosa (PA) binding to exfoliated epithelial cells and exfoliation rates. Concomitantly, we studied in a rabbit model, the effects of overnight lens wear on corneal epithelial surface cell viability (live/dead assay, TUNEL-labeling, Annexin-V staining, Bcl-2 expression), basal cell proliferation and migration patterns. The comprehensive results obtained yield important new insights on both the normal homeostasis of the corneal epithelium and the biological changes induced by contact lens wear.
 ...
PMID:Corneal epithelial homeostasis following daily and overnight contact lens wear. 1630 76

Pseudomonas aeruginosa is a gram-negative opportunistic pathogen that is cytotoxic towards a variety of eukaryotic cells. To investigate the effect of this bacterium on monocyte, we infected human U937 cells with the P. aeruginosa strain in vitro. To explore the expression of Bcl-2 and Bax as well as caspase-3/9 activation in the apoptosis of human U937 cells induced by P. aeruginosa, Hoechst 33258 staining and Giemsa staining as well as Flow cytometry analysis were used to determine the rate of apoptosis, and the expressions of Bcl-2 and Bax were assayed by RT-PCR and Western blotting respectively. Bax protein conformation change was assayed by immunoprecipitation. Cytochrome c release was measured by Western blotting. Moreover, exposure of U937 cells to P. aeruginosa measured caspase-3/9 activity. It was found that the apoptosis of human U937 cells could be induced by Pseudomonas aeruginosa in a dose- and time-dependent manner. Also, there were a tendency of alterations with an increased expression level of Bax and a reduced expression level of Bcl-2, increased levels of cytochrome c release, and also with an increased activation of caspase-3/9 and Bax protein conformation change. For the evaluation of the role of caspases, caspase-3/9 inhibitors Z-DEVD-FMK and Z-LEHD-FMK respectively were used. The results were further confirmed by the observation that the caspase inhibitors Z-DEVD-FMK and Z-LEHD-FMK blocked P. aeruginosa-induced U937 apoptosis. It is concluded that P. aeruginosa can induce apoptosis with an up-regulated expression of Bax and a down-regulated expression of Bcl-2, which resulted in increased levels of cytochrome c release and increased caspase-3 and -9 in human U937 cells.
 ...
PMID:Role of Bcl-2 family members in caspase-3/9-dependent apoptosis during Pseudomonas aeruginosa infection in U937 cells. 1841 81


1 2 3 4 Next >>