Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

M1 clone S6 myeloid leukemic cells do not express detectable p53 protein. When stably transfected with a temperature-sensitive mutant of p53, these cells undergo rapid cell death upon induction of wild-type (wt) p53 activity at the permissive temperature. This process has features of apoptosis. In a number of other cell systems, wt p53 activation has been shown to induce a growth arrest. Yet, wt 53 fails to induce a measurable growth arrest in M1 cells, and cell cycle progression proceeds while viability is being lost. There exists, however, a relationship between the cell cycle and p53-mediated death, and cells in G1 appear to be preferentially susceptible to the death-inducing activity of wt p53. In addition, p53-mediated M1 cell death can be inhibited by interleukin-6. The effect of the cytokine is specific to p53-mediated death, since apoptosis elicited by serum deprivation is refractory to interleukin-6. Our data imply that p53-mediated cell death is not dependent on the induction of a growth arrest but rather may result from mutually incompatible growth-regulatory signals.
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PMID:p53-mediated cell death: relationship to cell cycle control. 844 87

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3), a seco-steroid hormone with potential antitumoral activities, has been recently reported to exert cytotoxic effects on C6 glioma cells. However, the molecular mechanisms which trigger this cell death remain unknown. We show here that this 1,25(OH)2D3-induced cell death is dependent upon protein synthesis and is accompanied by the expression of c-myc, p53, and gadd45 genes. Two other genes, coding for interleukin-6 and vaso-endothelial growth factor, are also upregulated after addition of 1,25(OH)2D3. This programmed cell death can be suppressed when cells are treated with forskolin, a drug which increases intracellular cAMP concentration, or with genistein, an inhibitor of tyrosine protein kinases. However, in spite of the demonstration of fragmented DNA in 1,25(OH)2D3-treated cells, the C6.9 cells used in this study do not show the classical morphological features of apoptosis. These results provide the first evidence for the existence of a programmed cell death triggered by 1,25(OH)2D3 in glioma cells and may provide a basis for the development of new therapeutic strategies. In addition, these data also suggest that the treatment of C6.9 cells with 1,25(OH)2D3 may be a useful model to study the molecular mechanisms involved in the programmed cell death of a cell of glial origin.
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PMID:1,25-Dihydroxyvitamin D3 induces programmed cell death in a rat glioma cell line. 895 66

Hepatoma Hep3B cell lines stably expressing a temperature-sensitive p53 species (p53-Val-135) displayed a reduced response to interleukin-6 (IL-6) when cultured at the wild-type (wt) p53 temperature (Wang, L., Rayanade, R., Garcia, D., Patel, K., Pan, H., and Sehgal, P. B. (1995) J. Biol. Chem. 270, 23159-23165). We now report that in such cultures IL-6 caused a rapid (20-30 min) and marked loss of cellular immunostaining for STAT3 and STAT5, but not for STAT1. The loss of STAT3 and STAT5 immunostaining was transient (lasted 120 min) and tyrosine kinase-dependent, and even though the loss was blocked by the proteasome inhibitors MG132 and lactacystin it was not accompanied by changes in cellular levels of STAT3 and STAT5 proteins suggesting that IL-6 triggered a rapid masking but not degradation of these transcription factors. STAT3 and STAT5 masking was accompanied by a reduction in IL-6-induced nuclear DNA-binding activity. The data suggest that p53 may influence Jak-STAT signaling through a novel indirect mechanism involving a wt p53-dependent gene product which upon cytokine addition is activated into a "STAT-masking factor" in a proteasome-dependent step.
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PMID:Proteasome- and p53-dependent masking of signal transducer and activator of transcription (STAT) factors. 903 May 16

Interleukin-6 (IL-6) is a growth factor for multiple myeloma (MM) cells and can inhibit MM cell apoptosis. Our recent studies show that IL-6 facilitates MM cell growth via phosphorylation of retinoblastoma protein (pRB); however, the effects of IL-6 on those cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors (CDIs) that are known to regulate phosphorylation of pRB have not been defined in MM cells. In the present report, we cultured MM cell lines and patient cells with IL-6 and/or dexamethasone (Dex) and characterized changes in cell cycle; expression and association of cyclins, CDKs, and CDIs; and phosphorylation of pRB. Dex induced G1 growth arrest in MM cells, whereas IL-6 facilitated G1 to S phase transition; moreover, the effect of Dex was blocked by IL-6. p21WAF1 (p21) protein was constitutively expressed in the majority of MM cells independent of the status of p53. Its expression was upregulated by Dex and downregulated by IL-6; again, IL-6 inhibited the increase in p21 triggered by Dex. These alterations in p21 expression in MM cells were associated with changes in p21 binding to CDK2, CDK4, and CDK6; CDK2, CDK4, and CDK6 kinase activities; and phosphorylation of pRB. In contrast, expression of G1 cell cycle regulatory proteins, including p27KIP1, cyclin D2, and cyclin E, was not altered in MM cells cultured with Dex and/or IL-6. Finally, interferon-gamma (IFN-gamma) also induced G1 growth arrest and upregulated p21 protein expression; as with Dex, affects of IFN-gamma were inhibited by IL-6. Our results therefore show that changes in cell cycle distribution in MM cells triggered by Dex, IL-6, and IFN-gamma correlate with changes in p21 protein expression and implicate p21 in the coupling of Dex-, IL-6-, and IFN-gamma-related signals to G1 cell cycle regulation in MM cells.
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PMID:Interleukin-6 overcomes p21WAF1 upregulation and G1 growth arrest induced by dexamethasone and interferon-gamma in multiple myeloma cells. 920 63

Recently, considerable progress has been made in understanding of the biology and treatment of multiple myeloma. Molecular genetic abnormalities such as bcl-2,c-myc, ras, p53, and Rb genes have been identified in this disease and are related to a poor prognosis. Cytokine studies have revealed that interleukin-6 is a potent growth factor for myeloma cells and is also responsible for the progressive bone resorption together with interleukin-1 beta and tumor necrosis factor. Myeloablative chemotherapy followed by allogeneic or autologous hematopoietic stem cell transplantation has increased the incidence of complete remission. However, relapses are still observed because of drug resistance of tumor cells. Immunotherapeutic approaches targeting to cell surface antigens and interleukin-6 signals are being developed to further eliminate myeloma cells. Translating new biological advances into treatment protocols is essential to improve the prognosis of multiple myeloma.
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PMID:Multiple myeloma: new aspects of biology and treatment. 959

Strategies that enable E1-defective recombinant adenoviruses to selectively undergo replication in neoplastic tissue may be useful for future investigations or therapies of malignancies. A growing body of evidence suggests that some molecular alterations commonly associated with malignancies, such as p53 mutations, can modify the specific E1 requirements for replication of human serotype adenoviruses. In the studies reported here, a panel of human non-small cell lung cancer cell lines with previously defined p53 status were characterized for basal interleukin-6 (IL-6) and bcl-2 content because previous studies have indicated both proteins can functionally substitute for the replication requirements provided by native E1 viral proteins. Cell lines were infected with E1-defective adenovirus 5 and simultaneously transfected with different combinations of E1 plasmids, or a bcl-2 expression plasmid, and adenovirus present in the cells was quantified 6 days later. These assays demonstrated that E1A with both 19- and 55-kDa E1B-encoding plasmids were required for maximal adenoviral replication, independent of the varying p53/IL-6/basal bcl-2 phenotypes of the host cell lines. E1A was required for maximal replication enablement, independent of the basal IL-6 content of these cell lines, and exogenous IL-6 also did not obviate the E1A requirement. Interestingly, the bcl-2 expression plasmid did not consistently substitute for the 19-kDa expression plasmid in the context of this replication complementation assay. These results suggest that (1) basal levels of IL-6 greater than that present in these cell lines are necessary for functional replacement of the E1A replication function and (2) bcl-2 does not predictably substitute for the 19-kDa E1B replication function in the context of trans complementation.
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PMID:trans E1 component requirements for maximal replication of E1-defective recombinant adenovirus. 972 Dec 48

A unique subclone of a bone marrow-derived stromal cell line, BMS2.4, produces soluble factors that inhibit proliferation of several types of hematopoietic cell lines. An understanding of these molecules may be informative about negative regulatory circuits that can potentially limit blood cell formation. We used expression cloning to identify interleukin-6 (IL-6) as one factor that suppressed growth of a pre-B-cell variant line, 1A9-M. Moreover, IL-6 induced macrophage-differentiation and apoptosis of 1A9-M cells. During this process, IL-6 downregulated expression of BCL2 in 1A9-M cells and stimulated BCL-XL expression, but had no effect on p53, Bax, or Bak gene expression. Mechanisms for transduction of IL-6-induced signals were then evaluated in IL-6-stimulated 1A9-M cells. Whereas the signal transducer and activator of transcription 3 (Stat3) was phosphorylated and activated, there was no effect on either Stat1 or Stat5. The importance of BCL2 and Stat3 on IL-6-induced macrophage-differentiation and apoptosis was studied with 1A9-M cells expressing human BCL2 or a dominant-negative form of Stat3, respectively. IL-6-induced apoptosis, but not macrophage-differentiation, was blocked by continuously expressed BCL2. A dominant-negative form of Stat3 inhibited both macrophage-differentiation and apoptosis induced by IL-6. However, diminished Stat3 activity did not prevent IL-6-induced downregulation of the BCL2 gene. Therefore, activation of Stat3 is essential for IL-6-induced macrophage-differentiation and programmed cell death in this model. Whereas overexpression of BCL2 abrogates the apoptotic response, Stat3-independent signals appear to downregulate expression of the BCL2 gene.
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PMID:Both Stat3-activation and Stat3-independent BCL2 downregulation are important for interleukin-6-induced apoptosis of 1A9-M cells. 994 78

In human ovarian carcinomas, the p53 tumor-suppressor gene is frequently mutated. Interleukin-6 (IL-6) in these tumors is known to stimulate tumor-cell proliferation. In order to evaluate the effect of several p53 phenotypes on the IL-6 promoter activity, the human ovarian wild-type (wt)-p53 cell line A2780 was stably transfected with an empty plasmid (CMV) or (m)-175-, m-248- or m-273-p53. Electrophoretic mobility-shift assays revealed differences in activator protein-1 (AP-1) DNA-binding activity in the various clones. The CMV and m-273 clone had comparable amounts of AP-1. The m-175 clone displayed the least and m-248 the most pronounced AP-1 binding. Supershift analysis of AP-1/DNA complexes with antibodies against the AP-1 sub-units, c-Fos, FosB, Fra-1, Fra-2, c-Jun, JunB, and JunD, revealed that the AP-1/DNA complexes in the various clones had different compositions. Fra proteins were basically present only in m-175 and m-248 AP-1. IL-6-promoter activity was evaluated in the presence and absence of the AP-1 binding site which showed that the m-175-transfected clone has a transcriptional suppressing AP-1, whereas the CMV and the m-273 clones have an activating AP-1. Exposure of the p53 clones to tumor-necrosis factor-alpha (TNF-alpha) clearly altered the AP-1/DNA complex composition. IL-6-promoter activity was enhanced by TNF-alpha irrespective of the presence of an AP-1 binding site, while the degree of activation differed in the various clones, being most pronounced in the m-175 and m-248 clones. The results demonstrate that the basic and activated IL-6-promoter activity is differently regulated in the various p53 clones, possibly due to alterations in the AP-1 composition.
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PMID:Differential regulation of IL-6 promoter activity in a human ovarian-tumor cell line transfected with various p53 mutants: involvement of AP-1. 1018 25

Recent advances in the biology of multiple myeloma cell growth and survival have suggested new avenues for treatment and potential cure of this disease. Adhesion molecules on the myeloma cell surface mediate their localization in the bone marrow via binding to extracellular matrix proteins and stromal cells. Stromal cell to tumor cell contact and the secretion of transforming growth factor by tumor cells triggers interleukin-6 secretion from stromal cells and paracrine tumor cell growth. CD40 activation of myeloma cells changes their cell surface phenotype, triggers autocrine interleukin-6 secretion, and can regulate myeloma cell cycle in a p53-dependent fashion. Interleukin-6 is both a growth and survival factor for myeloma cells, and delineation of the signaling cascades mediating its effects permits the development of novel therapies either to interrupt growth or trigger apoptosis. New immune therapies offer the opportunity to treat minimal residual disease after stem cell transplantation, thereby improving outcome. Selected donor lymphocyte infusions after allografting and infusion of activated autologous T cells following autografting are examples of adoptive immunotherapy. Myeloma cell to dendritic cell fusions have been used in a vaccination strategy both to prevent and treat myeloma in an animal model, providing the rationale for similar clinical trials in humans. For the first time, a variety of novel treatment strategies derived from advances in understanding the disease pathogenesis offer the potential to achieve long-term disease-free survival in patients with multiple myeloma.
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PMID:Advances in the biology of multiple myeloma: therapeutic applications. 1052 90

Cyclooxygenase (COX)-2 levels are elevated in several types of human cancer tissues. Nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit both the COX-1 and COX-2 protein, the two enzymes that convert arachidonic acids to prostaglandins. Regular use of such NSAIDs significantly reduces the risk and spread of some cancers. The objective of this study was to elucidate the molecular pathology of neoplasms that overexpress COX-2. Epidemiological data and clinical studies were analyzed and compared with results of studies of human tumor tissues, animal models, and cultured tumor cells. COX-2, but not COX-1, is highly expressed in human colon carcinoma, squamous cell carcinoma of the esophagus, and skin cancer. COX-2 is inducible by oncogenes ras and scr, interleukin-1, hypoxia, benzo[a]pyrene, ultraviolet light, epidermal growth factor, transforming growth factor beta, and tumor necrosis factor alpha. Dexamethasone, antioxidants, and tumor-suppressor protein p53 suppress COX-2 expression. COX-2 synthesizes prostaglandin E2 (PGE2) which stimulates bcl-2 and inhibits apoptosis, and induces interleukin-6 (IL-6) which enhances haptoglobin synthesis. PGE2 is associated with tumor metastases, IL-6 with cancer cell invasion, and haptoglobin with implantation and angiogenesis. Drastic reduction in polyp number results from COX-2 gene knockout as well as from selective COX-2 inhibition in a mouse model of human familial adenomatous polyposis. Nonselective NSAIDs, for instance aspirin, and selective COX-2 inhibitors such as celecoxib (SC-58635) and NS-398 suppress azoxymethane-induced colon carcinogenesis in rats. Aspirin, indomethacin, and ibuprofen decrease cultured lung cancer cell proliferation. Selective inhibition of COX-2 is preferable to nonselective inhibition. It reduces cancer cell proliferation, induces cancer cell apoptosis, and spares COX-1-induced cytoprotection of the gastrointestinal tract.
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PMID:Molecular pathology of cyclooxygenase-2 in neoplasia. 1067 79


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