Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:A9QXG9 (bcl-2)
 7,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mature podocytes are regarded as growth-arrested cells with characteristic phenotypic features that underlie their function. To determine the relationship between cell cycle regulation and differentiation, the spatiotemporal expression of cyclin A, cyclin B1, cyclin D1, the cyclin-dependent kinase inhibitors (CKIs) p27 and p57, and markers of differentiating podocytes in developing human kidneys was investigated by immunohistochemistry. In S-shaped body stage, Ki-67, a cell proliferation marker that labels the G1/S/G2/M phase, was expressed in the majority (more than 80%) of presumptive podocytes, along with cyclin A (approximately 20% of the Ki-67-positive cells) and cyclin B1 (less than 5% of Ki-67-positive cells) expression. Among these cells), cyclin D1 and CKIs were markedly down-regulated. At the capillary-loop stage, by contrast, CKIs and cyclin D1 were intensely positive in podocytes, whereas no Ki-67, cyclin B1, or cyclin A expression was seen. Moreover, double-immunolabeling and serial-section analysis provided evidence that CKIs and markers specific for differentiating podocytes, namely PHM-5 (podocalyxin-like protein in humans), synaptopodin (a foot process-related protein), and C3b receptor, were co-expressed at the capillary-loop stage. Podocytes were the only cells within the glomeruli that expressed CKIs at immunohistochemically detectable levels. Furthermore, bcl-2 (an apoptosis inhibitory protein) showed a reciprocal expression pattern to that of CKI. These results suggest that 1) the cell cycle of podocytes is regulated by cyclin and CKIs, 2) CKIs may act to arrest the cell cycle in podocytes at the capillary-loop stage, and 3) the specific cell cycle system in podocytes may be closely correlated with their terminal differentiation in humans.
 ...
PMID:Cell cycle regulation and differentiation in the human podocyte lineage. 981 43

Bcl-2 is present in a cytoplasmic distribution in cells that express high levels of this oncoprotein. In contrast, using immunocytochemistry in cells expressing low levels of bcl-2, such as KB human carcinoma cells, we and others have shown that bcl-2 is present on the surface of mitotic chromosomes. However, monoclonal antibodies reactive with an epitope representing amino acids 41-54 of the bcl-2 sequence did not detect bcl-2 in other phases of the cell cycle. This study extended those earlier findings to determine if bcl-2 was expressed as a cyclin or if this pattern was an artifact of immunocytochemistry. Immunofluorescence studies in several other human cell lines showed the same mitotic distribution of bcl-2. Other studies using flow cytometry also showed selective mitotic phase detection of bcl-2. A comparison of available commercial antibodies showed that, in spite of reactivity with denatured bcl-2 on Western blots, clear reactivity with bcl-2 in fixed cells was found only with those reactive with the (a.a. 41-54) epitope. With RNase protection and Western blot analyses, cells synchronized at various stages of the cell cycle showed constant levels of bcl-2 mRNA and protein. Analysis of bcl-2 using Western blots showed a band with the same apparent molecular weight as that seen in comparison with authentic bcl-2 overexpressed in the cytoplasm. The retention of bcl-2 on chromosomes in unfixed, permeabilized preparations was influenced by protease treatment, phosphate, and pH. Studies using isolated chromosomes showed that much of the bcl-2 in these cells was attached to chromosomes in mitosis, had the expected molecular weight, and was phosphorylated in the same manner as that seen in whole-cell extracts. These results show that bcl-2 is not a cyclin and that the bcl-2 localized on chromosomes is the same molecule seen by immunoblotting. These results suggest that the reactive (a.a. 41-54) epitope present in bcl-2 is somehow modified or masked in interphase.
 ...
PMID:Mitotic chromosomal bcl-2. I. Stable expression throughout the cell cycle and association with isolated chromosomes. 988 50

Transforming growth factor-beta1 (TGF-beta1) acts directly on haemopoietic progenitor cells to regulate their growth. To investigate a possible link between the action of TGF-beta1 and cell death regulators such as bcl-2, we utilized Ba/F3 cells, the interleukin-3 (IL-3)-dependent growth of which could be modulated by TGF-beta1, as well as haemopoietic progenitor cells. We demonstrate here that up-regulation of bcl-2 protein (Bcl-2) as well as that of an inhibitor of cyclin/cyclin-dependent kinase complex, p27, was associated with TGF-beta1-induced deceleration of the cell-cycling of haemopoietic progenitor cells and Ba/F3 cells. The data from cell-cycle analysis of Ba/F3 cells showed that TGF-beta1 retarded the G1 to S phase transition. Analysis of cells with the potential to express Bcl-2 in an inducible manner indicated that up-regulation of Bcl-2 was sufficient for not only an increase in the level of p27 but also to inhibit the cell growth. Using c-kit-overexpressing cells, we observed that the potential of TGF-beta1 to up-regulate the expression of Bcl-2 and p27 could be counteracted by the c-kit ligand, stem cell factor. These results demonstrate that Bcl-2 exerts an essential function in the regulation of G1 to S phase transition of haemopoietic cells by TGF-beta1.
 ...
PMID:Possible involvement of bcl-2 in regulation of cell-cycle progression of haemopoietic cells by transforming growth factor-beta1. 1023 23

p21((WAF1/SDII/CIP1)) (p21) arrests cell growth by inhibiting cyclin-depend kinases. To explore the potential of using p21 for the gene therapy of cervical cancer, we infected human papillomavirus (HPV)-positive cervical cancer cells (HeLa, SiHa, and Z172) and HPV-negative cervical cancer cells (C33A) with recombinant adenovirus encoding p21 cDNA. The results revealed that effective inhibition of cell growth could be achieved by sense p21 adenovirus but not antisense p21 adenovirus infection and occurred through apoptosis as measured by DNA fragmentation and chromatin condensation. Apoptosis was also observed in xenografts of human cervical cancer cells infected with sense p21 adenovirus, as confirmed by in situ terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL). The apoptosis was not prevented by overexpression of the bcl-2 transgene. To sum up, the apoptotic effect suggests that p21 should be a tumoricidal agent instead of a tumoristatic agent in preventing cervical cancers. In addition, our report substantiates the combination of the high efficiency of adenovirus vector-mediated gene delivery and the apoptotic effect of p21.
 ...
PMID:Adenovirus-mediated p21((WAF1/SDII/CIP1)) gene transfer induces apoptosis of human cervical cancer cell lines. 1023 60

We had previously shown that the drug undecylprodigiosin (UP) blocks human lymphocyte proliferation in vitro. We have now investigated the mechanism of action of a new analogue of UP, PNU156804, which shows a more favorable activity profile than UP in mice. We demonstrate here that the biological effect of PNU156804 in vitro is indistinguishable from UP: PNU156804 blocks human T cell proliferation in mid-late G1, as determined by cell cycle analysis, expression of cyclins, and cyclin-dependent kinases and retinoblastoma phosphorylation. In addition, we show that PNU156804 does not block significantly the induction of either IL-2 or IL-2R alpha- and gamma-chains but inhibits IL-2-dependent T cell proliferation. We have investigated several molecular pathways that are known to be activated by IL-2 in T cells. We show that PNU156804 does not inhibit c-myc and bcl-2 mRNA induction. On the other hand, PNU156804 efficiently inhibits the activation of the NF-kappa B and AP-1 transcription factors. PNU156804 inhibition of NF-kappa B activation is due to the inhibition of the degradation of I kappa B-alpha and I kappa B-beta. PNU156804 action is restricted to some signaling pathways; it does not affect NF-kappa B activation by PMA in T cells but blocks that induced by CD40 cross-linking in B lymphocytes. We conclude that the prodigiosin family of immunosuppressants is a new family of molecules that show a novel target specificity clearly distinct from that of other immunosuppressive drugs such as cyclosporin A, FK506, and rapamycin.
 ...
PMID:New immunosuppressive drug PNU156804 blocks IL-2-dependent proliferation and NF-kappa B and AP-1 activation. 1035 54

The alphav integrin subunit is highly expressed in osteoclasts where it dimerizes with beta1 and beta3 subunits to form receptors for vitronectin and bone sialoproteins. Inhibition of osteoclast adhesion and function has previously been achieved by alphavbeta3 antibodies or Arg-Gly-Asp-containing peptides which have the disadvantages of blocking a single receptor type, or of being rather nonspecific, respectively. Here we show that alphav integrin expression in rabbit osteoclasts can be inhibited by partially phosphorothioated antisense oligodeoxynucleotide (ODN) spanning the adenine-uracil-guanine (AUG) translational start site of the human/rabbit alphav gene, a procedure which offers the advantage of affecting all the alphav receptors with high efficiency. The alphav antisense ODN caused a dose-dependent, substrate-specific reduction of osteoclast adhesion and bone resorption. Control ODNs, such as sense, inverted, and mismatch, were without effect, providing evidence of specificity of the antisense reagent. It is likely as a consequence of loss of substrate interaction, the antisense ODN induced osteoclast retraction and apoptosis, increase of the cyclin/cyclin-dependent kinase complex inhibitor p21WAF1/CIP1, and inhibition of the cell survival gene, bcl-2. Although the expression of the cell death-promoting gene, bax, remained unchanged, a reduction of the bcl-2/bax ratio, known to underlie the intracellular signal to apoptosis, was observed. This finding led us to hypothesize that these changes could provide a link between reduction of alphav synthesis and osteoclast programmed death. In conclusion, this study provides novel insights into the use of alphav antisense ODN as an efficacious mechanism for blocking osteoclast function and underscores for the first time the involvement of integrins in bone cell apoptosis. In vivo studies may verify potential application of this ODN as alternative therapy for bone diseases.
 ...
PMID:Oligodeoxynucleotide targeted to the alphav gene inhibits alphav integrin synthesis, impairs osteoclast function, and activates intracellular signals to apoptosis. 1057 87

The aim of this study was to assess the clinical significance and potential prognostic value of the expression of a panel of surface markers, proliferating, suppressor and oncogenic proteins in diffuse large B-cell lymphomas (DLBCL). Biopsies were collected from 158 patients with DLBCL and analyzed immunohistochemically for p53, p21/WAF1, bcl-2, cyclin-D1, bcl-6, mdr, CD5, CD30, epithelial membrane antigen (EMA), Ki-67 and c-myc positive tumor cells. Among these, 76 young and middle-aged patients (20-65 years) were selected to investigate the relationship between protein expression, clinical features, and survival. Survival analysis showed that advanced stage, high lactic dehydrogenase level, and high International Prognostic Index (IPI) were poor prognostic factors associated with a shorter overall survival (OS) and disease-free survival (DFS) times. A high p53 expression and low bcl-6 expression were associated with a shorter DFS time. The histological variant type, cyclin-D1+ CD5+ DLBCL, positive epithelial membrane antigen (EMA+) CD30- DLBCL, high bcl-2 expression, and low Ki-67 proliferation activity tended to be associated with worse survival, but the correlations were not statistically significant. In the multivariate analysis, the most significant factors were age, followed by IPI and last p53. The expression of p21/WAF1, mdr, and c-myc proteins did not influence OS and DFS. The expression of p53 and bcl-6 proteins may be useful prognostic indicators in DLBCL. Cyclin-D1+ CD5+ or EMA+ CD30- DLBCL tended to predict a worse survival and may probably bear a significant prognostic value worthy of consideration. Overall, clinical factors appeared to be more important than biologic parameters in determining the prognosis of diffuse large B-cell lymphomas.
 ...
PMID:Prognostic clinicopathologic factors, including immunologic expression in diffuse large B-cell lymphomas. 1063 24

Kaposi's sarcoma (KS) is a skin disease characterised by spindle cells proliferation and neovascularisation which, in 1994, was associated with a new Gammaherpesvirinae, named human herpesvirus 8 (HHV8). The HHV8 genome, containing more than 140 kilobases, includes genes encoding structural proteins and enzymes, and some homologues to cellular genes which could have been captured in host cells during viral evolution. Several HHV8 proteins interfere with the host cellular cycle either by inhibiting apoptosis or by positive regulation of the cell cycle (viral cyclin or v-cyclin, v-bcl-2, v-FLIP). HHV8 also contains potential oncogenes (v-IRF and v-GPCR, which promote angiogenesis, in particular the secretion of VEGF) as well as homologues of human cytokines and chemokines (v-IL6, v-MIP). HHV8 is clearly associated with KS, multicentric Castleman disease and primary effusion lymphoma. Most of the cells are infected by latent virus, resulting in persistent infection of the lesions. Only a minority of infected cells yield infectious viral particles, and their role in the development of KS and other associated diseases has not been clearly established. The molecular mechanisms and cofactors involved in the physiopathology of this infection have yet to be identified.
 ...
PMID:[Kaposi's disease and HHV8: a new model of virus-induced tumorigenesis]. 1096 29

Ginseng is a medicinal herb widely used in Asian countries, and many of its pharmacological actions are attributed to the ginsenosides. In a study of the anti-proliferative activity of ginsenosides using human prostate carcinoma LNCaP cell line, ginsenoside Rg3 displayed growth inhibitory activity. The cells lost its adherent property after incubation in the presence of 250 microM of ginsenoside for 48h. The expression of biomarker genes, including prostate specific antigen (PSA), androgen receptor (AR) and 5alpha-reductase (5alphaR), and that of the proliferating cell nuclear antigen (PCNA), were suppressed. Ginsenoside Rg3 induced classic apoptotic morphology and interfered with the expression of apoptosis-related genes, bcl-2 and caspase-3, in LNCaP cells, as demonstrated by fluorescence microscopy, flow cytometry and reverse transcriptase-polymerase chain reaction. Taken our results together, we suggested that ginsenoside Rg3 activated the expression of cyclin-kinase inhibitors, p21 and p27, arrested LNCaP cells at G1 phase, and subsequently inhibited cell growth through a caspase3-mediated apoptosis mechanism.
 ...
PMID:Anti-proliferative effect of ginseng saponins on human prostate cancer cell line. 1097 98

Monocytoid B cells (MBCs) are a subset of B cells that may be recognized in several reactive and tumoral lymph node conditions, including toxoplasmic lymphadenitis, infectious mononucleosis, and Hodgkin's lymphoma. Although this is a commonly observed cell population, which has even given its name to a type of lymphoma, MBC lymphoma, scarcely any information is available about the function and characteristics of this cell type. A relationship with marginal zone (MZ) B lymphocytes has been claimed for MBCs, but this has not yet been fully proven. Indeed, specific markers for MBCs are still lacking, which has made it difficult to analyze their relationship with other B cell subpopulations and confirm the existence of tumors deriving from this B cell subset. We used a panel of cell cycle markers to explore the characteristics of MBCs and their relationship with MZ B cells, nodal MZ lymphoma, and splenic MZ lymphoma. We therefore compared the phenotypic profile of MBCs in different conditions with normal MZ B cells within the spleen and mesenteric lymph nodes, with a group of seven cases of nodal MZ/MBC lymphoma and another group of five cases of splenic MZ lymphoma. MBCs were mainly in the G(0) to G(1) phases, as deduced from the presence of a proportion of between 10 and 35% Ki67-positive cells, whereas very low expression was observed with cyclin A and cyclin B staining. Nests of MBCs were clearly labeled by the expression of p21(WAF1), a cyclin-dependent kinase inhibitor (CKI), rarely detectable in benign lymphocytes, and by cyclin E. Basically all MBCs were bcl-2-negative, and high cyclin D2 and cyclin D3 were also detected in these cells, at proportions and intensities above expected levels, when the percentage of proliferating cells was taken into account. p27(KIP1) expression was characterized by homogeneous reactivity, higher than that observed in other B cell populations with a relatively high-growth fraction. Immunoglobulin staining showed undetectable light and heavy chains. However, splenic MZ cells, nodal MZ lymphoma, and splenic MZ lymphoma showed a distinct expression of IgM and bcl-2, with high p27 (KIP1) nuclear expression and undetectable or low levels of cyclin A, B, E, or D, or p21(WAF1) expression. The data from this study show an unexpected immunophenotype in MBCs, different from the one observed in splenic and lymph node MZ B cells. This suggests that either MBCs are a unique B cell population from a distinct cell lineage, or if related to MZ cells, they would represent a definite differentiation stage characterized by a distinctive immunophenotype. They also show so-called MZ/MBC lymphoma to be more closely related to lymph node and splenic MZ B cells, as they do not share the most distinctive features of MBCs.
 ...
PMID:Unique phenotypic profile of monocytoid B cells: differences in comparison with the phenotypic profile observed in marginal zone B cells and so-called monocytoid B cell lymphoma. 1129 May 54


<< Previous 1 2 3 4 5 6 7 Next >>