134 research outputs found
erbB-2 antisense oligonucleotides inhibit the proliferation of breast carcinoma cells with erbB-2 oncogene amplification.
Amplification and overexpression of the erbB-2 oncogene is an unfavourable prognostic marker in human breast cancer and occurs in approximately 25% of breast carcinomas. We used erbB-2 antisense oligonucleotides to inhibit the proliferation of human breast cancer cell lines. erbB-2 antisense oligonucleotides (20 microM) inhibited the growth and DNA synthesis of breast cancer cell lines with an amplified erbB-2 gene by up to 60%. Control complementary sense oligonucleotides did not inhibit cellular proliferation at the same concentration but showed inhibitory effects at higher concentrations. There was no specific effect of erbB-2 antisense oligonucleotides on breast cancer cell lines that had no amplification of erbB-2. erbB-2 antisense oligonucleotides reduced erbB-2 protein levels, measured by immunohistochemistry, in a dose-dependent manner. erbB-2 sense oligonucleotides did not decrease the levels of erbB-2 protein. These data indicate that erbB-2 antisense oligonucleotides induce a specific inhibition of erbB-2 protein expression and that erbB-2 gene overexpression is important for the proliferation of the breast cancer cells that have been selected for erbB-2 amplification
-Catenin Binds to the Activation Function 2 Region of the Androgen Receptor and Modulates the Effects of the N-Terminal Domain and TIF2 on Ligand-Dependent Transcription
β-Catenin is a multifunctional molecule that is activated by signaling through WNT receptors. β-Catenin can also enhance the transcriptional activity of some steroid hormone receptors such as the androgen receptor and retinoic acid receptor α. Androgens can affect nuclear translocation of β-catenin and influence its subcellular distribution. Using mammalian two-hybrid binding assays, analysis of reporter gene transcription, and coimmunoprecipitation, we now show that β-catenin binds to the androgen receptor ligand-binding domain (LBD) and modulates the transcriptional effects of TIF2 and the androgen receptor N-terminal domain (NTD). In functional assays, β-catenin bound to androgen receptor only in the presence of ligand agonists, not antagonists. β-Catenin binding to the androgen receptor LBD was independent of and cooperative with the androgen receptor NTD and the p160 coactivator TIF2, both of which bind to the activation function 2 (AF-2) region of the androgen receptor. Different mutations of androgen receptor helix 3 amino acids disrupted binding of androgen receptor NTD and β-catenin. β-Catenin, androgen receptor NTD, and TIF2 binding to the androgen receptor LBD were affected similarly by a subset of helix 12 mutations, but disruption of two sites on helix 12 affected only binding of β-catenin and not of TIF2 or the androgen receptor NTD. Mutational disruption of each of five LXXLL peptide motifs in the β-catenin armadillo repeats did not disrupt either binding to androgen receptor or transcriptional coactivation. ICAT, an inhibitor of T-cell factor 4 (TCF-4), and E-cadherin binding to β-catenin also blocked binding of the androgen receptor LBD. We also demonstrated cross talk between the WNT and androgen receptor signaling pathways because excess androgen receptor could interfere with WNT signaling and excess TCF-4 inhibited the interaction of β-catenin and androgen receptor. Taken together, the data show that β-catenin can bind to the androgen receptor LBD and modulate the effects of the androgen receptor NTD and TIF2 on transcription
Isospin and isospin/strangeness correlations in relativistic heavy ion collisions
A fundamental symmetry of nuclear and particle physics is isospin whose third
component is the Gell-Mann/Nishijima expression I(z)=Q-(B+S)/2 . The role of
isospin symmetry in relativistic heavy ion collisions is studied. An isospin
I(z), strangeness S correlation is shown to be a direct and simple measure of
flavor correlations, vanishing in a Qg phase of uncorrelated flavors in both
symmetric N=Z and asymmetric N not equal to Z systems. By contrast, in a hadron
phase, a I(z)/S correlation exists as long as the electrostatic charge chemical
potential mu(Q)does not equal 0 as in N not equal to Z asymmetric systems. A
parallel is drawn with a Zeeman effect which breaks a spin degeneracyComment: 11 page
Expression analysis onto microarrays of randomly selected cDNA clones highlights HOXB13 as a marker of human prostate cancer
In a strategy aimed at identifying novel markers of human prostate cancer, we performed expression analysis using microarrays of clones randomly selected from a cDNA library prepared from the LNCaP prostate cancer cell line. Comparisons of expression profiles in primary human prostate cancer, adjacent normal prostate tissue, and a selection of other (nonprostate) normal human tissues, led to the identification of a set of clones that were judged as the best candidate markers of normal and/or malignant prostate tissue. DNA sequencing of the selected clones revealed that they included 10 genes that had previously been established as prostate markers: NKX3.1, KLK2, KLK3 (PSA), FOLH1 (PSMA), STEAP2, PSGR, PRAC, RDH11, Prostein and FASN. Following analysis of the expression patterns of all selected and sequenced genes through interrogation of SAGE databases, a further three genes from our clone set, HOXB13, SPON2 and NCAM2, emerged as additional candidate markers of human prostate cancer. Quantitative RT–PCR demonstrated the specificity of expression of HOXB13 in prostate tissue and revealed its ubiquitous expression in a series of 37 primary prostate cancers and 20 normal prostates. These results demonstrate the utility of this expression-microarray approach in hunting for new markers of individual human cancer types
A SEARCH FOR RETROVIRUS INFECTION IN SYSTEMIC LUPUS-ERYTHEMATOSUS AND RHEUMATOID-ARTHRITIS
Evidence for retroviral infection in general and human immunodeficiency virus (HIV) infection in particular was sought in freshly isolated peripheral blood T cells, B cells, and monocyte-macrophages from patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) and also in T cell and B cell lines established from the same source. Similar cells isolated from rheumatoid synovial membrane were also examined. The strategy used for the detection of virus was cocultivation with susceptible cell lines looking for syncytia formation, reverse transcriptase production, and nucleic acid hybridisation with HIV cDNA probes. No evidence for infection was obtained
The progestational and androgenic properties of medroxyprogesterone acetate: gene regulatory overlap with dihydrotestosterone in breast cancer cells
INTRODUCTION: Medroxyprogesterone acetate (MPA), the major progestin used for oral contraception and hormone replacement therapy, has been implicated in increased breast cancer risk. Is this risk due to its progestational or androgenic properties? To address this, we assessed the transcriptional effects of MPA as compared with those of progesterone and dihydrotestosterone (DHT) in human breast cancer cells. METHOD: A new progesterone receptor-negative, androgen receptor-positive human breast cancer cell line, designated Y-AR, was engineered and characterized. Transcription assays using a synthetic promoter/reporter construct, as well as endogenous gene expression profiling comparing progesterone, MPA and DHT, were performed in cells either lacking or containing progesterone receptor and/or androgen receptor. RESULTS: In progesterone receptor-positive cells, MPA was found to be an effective progestin through both progesterone receptor isoforms in transient transcription assays. Interestingly, DHT signaled through progesterone receptor type B. Expression profiling of endogenous progesterone receptor-regulated genes comparing progesterone and MPA suggested that although MPA may be a somewhat more potent progestin than progesterone, it is qualitatively similar to progesterone. To address effects of MPA through androgen receptor, expression profiling was performed comparing progesterone, MPA and DHT using Y-AR cells. These studies showed extensive gene regulatory overlap between DHT and MPA through androgen receptor and none with progesterone. Interestingly, there was no difference between pharmacological MPA and physiological MPA, suggesting that high-dose therapeutic MPA may be superfluous. CONCLUSION: Our comparison of the gene regulatory profiles of MPA and progesterone suggests that, for physiologic hormone replacement therapy, the actions of MPA do not mimic those of endogenous progesterone alone. Clinically, the complex pharmacology of MPA not only influences its side-effect profile; but it is also possible that the increased breast cancer risk and/or the therapeutic efficacy of MPA in cancer treatment is in part mediated by androgen receptor
Drivers of Health Care Expenditure: Does Baumol's Cost Disease Loom Large?
According to Baumol (1993) health care epitomises Baumol's cost disease. Sectors that suffer from Baumol's cost disease are characterised by slow productivity growth due to a high labour coefficient. As a result, unit costs of these sectors rise inexorably if the respective wages increase with productivity growth of the progressive industries such as manufacturing. Thus, according to Baumol (1993) the secular rise in health-care expenditure has been unavoidable. This present paper demonstrates that health care is contracted by Baumol's cost disease, but only to a minor extent. Consequently, policy-makers have more leeway to curbever-increasing health-care expenditure than is suggested by Baumol (1993) and other authors. In addition, we test the implications of Baumol's cost disease for health care by avoiding the well-known flaws in constructing medical price indices. Therefore, the adjusted Baumol variable derived in this paper is also extremely appropriate to test the validity of Baumol's cost diseases of other service industries such as education or the live performing arts. Additionally, our analysis suggests that health care is rather a necessity than a luxury at the national level, which conflicts with macroeconomic evidence provided in the relevant literature
Triptolide Inhibits the Proliferation of Prostate Cancer Cells and Down-Regulates SUMO-Specific Protease 1 Expression
Recently, traditional Chinese medicine and medicinal herbs have attracted more attentions worldwide for its anti-tumor efficacy. Celastrol and Triptolide, two active components extracted from the Chinese herb Tripterygium wilfordii Hook F (known as Lei Gong Teng or Thunder of God Vine), have shown anti-tumor effects. Celastrol was identified as a natural 26 s proteasome inhibitor which promotes cell apoptosis and inhibits tumor growth. The effect and mechanism of Triptolide on prostate cancer (PCa) is not well studied. Here we demonstrated that Triptolide, more potent than Celastrol, inhibited cell growth and induced cell death in LNCaP and PC-3 cell lines. Triptolide also significantly inhibited the xenografted PC-3 tumor growth in nude mice. Moreover, Triptolide induced PCa cell apoptosis through caspases activation and PARP cleavage. Unbalance between SUMOylation and deSUMOylation was reported to play an important role in PCa progression. SUMO-specific protease 1 (SENP1) was thought to be a potential marker and therapeutical target of PCa. Importantly, we observed that Triptolide down-regulated SENP1 expression in both mRNA and protein levels in dose-dependent and time-dependent manners, resulting in an enhanced cellular SUMOylation in PCa cells. Meanwhile, Triptolide decreased AR and c-Jun expression at similar manners, and suppressed AR and c-Jun transcription activity. Furthermore, knockdown or ectopic SENP1, c-Jun and AR expression in PCa cells inhibited the Triptolide anti-PCa effects. Taken together, our data suggest that Triptolide is a natural compound with potential therapeutic value for PCa. Its anti-tumor activity may be attributed to mechanisms involving down-regulation of SENP1 that restores SUMOylation and deSUMOyaltion balance and negative regulation of AR and c-Jun expression that inhibits the AR and c-Jun mediated transcription in PCa
Advances in estrogen receptor biology: prospects for improvements in targeted breast cancer therapy
Estrogen receptor (ER) has a crucial role in normal breast development and is expressed in the most common breast cancer subtypes. Importantly, its expression is very highly predictive for response to endocrine therapy. Current endocrine therapies for ER-positive breast cancers target ER function at multiple levels. These include targeting the level of estrogen, blocking estrogen action at the ER, and decreasing ER levels. However, the ultimate effectiveness of therapy is limited by either intrinsic or acquired resistance. Identifying the factors and pathways responsible for sensitivity and resistance remains a challenge in improving the treatment of breast cancer. With a better understanding of coordinated action of ER, its coregulatory factors, and the influence of other intracellular signaling cascades, improvements in breast cancer therapy are emerging
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