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Biomedical subjects

J Lin

Publications and source records attributed to J Lin.

At least 199 records · Page 11Linked to original sources
PubMed2000

Replication linkage study for prostate cancer susceptibility genes.

BACKGROUND: Since the publication of the first genome screen for prostate cancer (CaP) 5 years ago, over a dozen linkage studies have appeared. Most attention has been directed to chromosome 1, where two separate regions have been identified as harboring a prostate cancer susceptibility locus: HPC1 in the 1q24-25 interval and PCaP in the 1q42.2-43 interval. Linkage analysis of chromosome 16 has also provided evidence of harboring two loci predisposing to CaP. METHODS: We report on a replication linkage study of chromosomes 1 and 16 in 45 new and 4 expanded multiplex CaP families. Multipoint Z-scores were obtained for 30 highly polymorphic short-sequence tandem repeat markers spanning chromosome 1, and 22 markers spanning chromosome 16. RESULTS: The replication sample gave no evidence for a CaP susceptibility locus in the 1q24-25 interval and equivocal evidence for such a locus at 1q42.2-43. With respect to chromosome 16, positive Z-scores were obtained over a contiguous interval covering the entire p arm and the proximal half of the q arm. CONCLUSIONS: The linkage analysis of our replication sample does not support the existence of HPC1, and the evidence for the existence of PCaP remains equivocal. Evidence of a susceptibility locus on 16p remains strong, but the evidence for a susceptibility locus on 16q is weakened.

Chromosomes, Human, Pair 1↗
PubMed2000

Expression of inducible nitric oxide synthase (iNOS) in middle ear epithelial cells by IL-1beta and TNF-alpha.

OBJECTIVE: The importance of nitric oxide (NO) in the development of mucoid middle ear effusion (MMEE) has been reported, but the mechanism regulating NO release is unclear. We hypothesized that middle ear epithelial cells (MEEC) are an important source of NO and that cytokines may be responsible for inducible nitric oxide synthase (iNOS) mRNA expression in middle ear epithelial cells. This study aims to identify and localize iNOS in middle ear epithelium, and to characterize the effects of cytokines IL-1beta and TNF-alpha on the expression and regulation of iNOS in rat middle ear epithelial cells. METHODS: In vitro study: 40 Healthy adult Sprague-Dawley rats weighing 200-250 g were used as donors of MEEC. Cultured MEEC were exposed to IL-1beta (10 ng/ml), TNF-alpha (5 ng/ml) or PBS (negative control) stimulation for 16 h. In vivo study: A total of 45 healthy adult Sprague-Dawley rats weighing 200-250 grams were used for this study. The tympanic bullae were exposed bilaterally by a submandibular approach. Animals were equally divided into three groups and inoculated with either 250 ng of IL-1beta, 250 ng of TNF-alpha or PBS. A PBS group served as control. Expression of iNOS mRNA in MEEC from both in vivo and in vitro studies was determined by RT-PCR using specific primers. Expression of iNOS protein in MEEC was determined by immunocytochemistry and Western blot using specific anti-iNOS antibody. RESULTS: Primary culture of rat MEEC was positively stained by cytokeratin antibody, but not by vimentin, indicating the epithelial origin of the cultured cells. RT-PCR revealed that cultured MEEC without treatment of IL-1 beta or TNF-alpha did not express iNOS mRNA whereas cultured MEEC treated with IL-1beta or TNF-alpha for 16 h expressed iNOS mRNA. Both immunocytochemistry and Western blot demonstrated the expression of iNOS protein in the majority of cultured MEEC treated with IL-1beta or TNF-alpha for 16 h, whereas the expression of iNOS protein was not detectable in MEEC without treatment. Expression of iNOS protein in vivo was observed in middle ear mucosa treated with IL-1beta and TNF-alpha by immunohistochemistry. CONCLUSION: Expression of iNOS mRNA and iNOS protein is induced in MEEC following the treatment of cytokines IL-1beta or TNF-alpha both in vivo and in vitro. The results of the present study demonstrate that rat MEEC possess the capacity to express iNOS after IL-1beta and TNF-alpha stimulation.

Animals↗
PubMed2000

Antiangiogenic gene therapy for cancer via systemic administration of adenoviral vectors expressing secretable endostatin.

A growing number of antiangiogenesis strategies have been investigated for the treatment of cancer and other angiogenesis-dependent diseases. One of the most promising strategies is to systemically administer one or more antiangiogenic proteins frequently enough to achieve a sufficient long-term steady state level of the protein(s) to achieve the maximum beneficial effect. However, the utility of this strategy is limited because of many technical difficulties, including obtaining both the quantity and quality of the protein(s) necessary for optimal therapeutic benefit. To overcome these difficulties, we hypothesized that a single administration of a replication-defective adenoviral vector expressing a secretable antiangiogenic protein could achieve an optimal long-term systemic concentration. We constructed a recombinant adenoviral vector, Av3mEndo, which encodes a secretable form of murine endostatin. We demonstrated secretion of endostatin from several cell lines transduced with Av3mEndo. Partially purified endostatin secreted from Av3mEndo-transduced mammalian cells was shown to potently inhibit endothelial cell migration in vitro. A single intravenous administration of Av3mEndo in mice was shown to result in (1) prolonged and elevated levels of circulating endostatin, (2) partial inhibition of VEGF-induced angiogenesis in a VEGF implant angiogenesis model, and (3) prolonged survival and in 25% of mice the complete prevention of tumor growth in a prophylactic human colon/liver metastasis xenograft murine model. These results support our contention that adenoviral vector-mediated expression of an antiangiogenic protein(s) represents an attractive therapeutic approach to cancer and other angiogenesis-dependent diseases.

Adenoviridae↗
PubMed2000

An induced proximity model for NF-kappa B activation in the Nod1/RICK and RIP signaling pathways.

Nod1 is an Apaf-1-like molecule composed of a caspase-recruitment domain (CARD), nucleotide-binding domain, and leucine-rich repeats that associates with the CARD-containing kinase RICK and activates nuclear factor kappaB (NF-kappaB). We show that self-association of Nod1 mediates proximity of RICK and the interaction of RICK with the gamma subunit of the IkappaB kinase (IKKgamma). Similarly, the RICK-related kinase RIP associated via its intermediate region with IKKgamma. A mutant form of IKKgamma deficient in binding to IKKalpha and IKKbeta inhibited NF-kappaB activation induced by RICK or RIP. Enforced oligomerization of RICK or RIP as well as of IKKgamma, IKKalpha, or IKKbeta was sufficient for induction of NF-kappaB activation. Thus, the proximity of RICK, RIP, and IKK complexes may play an important role for NF-kappaB activation during Nod1 oligomerization or trimerization of the tumor necrosis factor alpha receptor.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Induction of mucin gene expression in middle ear of rats by tumor necrosis factor-alpha: potential cause for mucoid otitis media.

Mucoid otitis media (MOM) is characterized by viscous fluid, high in mucin concentration, which accumulates in the middle ear cavity. Recent studies suggest that initial infection in the middle ear cleft may be key to the development of MOM. However, factors of the initial infection attributed to the stimulation of mucin production are not clearly understood. This study demonstrated that tumor necrosis factor (TNF)-alpha, a proinflammatory cytokine in mucoid effusion, markedly increased Muc2 mucin mRNA expression in middle ear epithelium, in a time- and dose-dependent manner. Parallel to this was a marked increase in mucin glycoprotein in middle ear fluid. Also, TNF-alpha demonstrated an autocrine and/or paracrine effect on the expression of endogenous TNF-alpha gene in the middle ear, which may contribute to the production of mucin in this study. These findings suggest that TNF-alpha plays an important role in the development of MOM by stimulating mucin metabolism.

Animals↗
PubMed2000

Growth inhibition and modulation of kinase pathways of small cell lung cancer cell lines by the novel tyrosine kinase inhibitor STI 571.

Small cell lung cancer (SCLC) is an aggressive cancer characterized by several autocrine growth mechanisms including stem cell factor and its receptor c-Kit. In order to arrive at potentially new and novel therapy for SCLC, we have investigated the effects of the tyrosine kinase inhibitor, STI 571, on SCLC cell lines. It has been previously reported that STI 571 does not only inhibit cellular Abl tyrosine kinase activity but also the PDGF receptor and c-Kit tyrosine kinases at similar concentrations (approximately 0.1 microM). There is no expression of the PDGF-receptor, and the Abl kinase is not activated by SCLC, but over 70% of SCLC contain the c-Kit receptor. Utilizing this preliminary data, we have determined that three (NCI-H69, NCI-H146 and NCI-H209) of five (including NCI-H82 and NCI-H249) SCLC cell lines had detectable c-Kit receptors and were inhibited in growth and viability at concentrations 1 - 5 microM of STI 571 after 48 h of treatment. The SCLC cell lines, NCI-H69, NCI-H146 and NCI-H209, showed a dose-response (tested between 0.1 - 10 microM) inhibition of tyrosine phosphorylation of c-Kit as well as in vitro kinase activity (at 5 microM) of c-Kit in response to STI 571. STI 571 inhibited cell motility, as assessed by time-lapsed video microscopy, within 6 h of STI 571 treatment (5 microM). STI 571 also decreased intracellular levels of reactive oxygen species (ROS) by at least 60%, at a concentration (5 microM) that also inhibited cell growth. Cell cycle analysis of STI 571 responsive cells showed that cells were generally slowed in G2/M phase, but there was no arrest at G1/S. A downstream phosphorylation target of c-Kit, Akt, was not phosphorylated in response to stem cell factor in the presence of STI 571. These data imply that STI 571 inhibits growth of SCLC cells through a mechanism that involves inactivation of the tyrosine kinase c-Kit. The effectiveness of STI 571 in this study suggests this drug may be useful in a clinical trial, for patients with SCLC. Oncogene (2000) 19, 3521 - 3528

Animals↗
PubMed2000

The deuterium isotope effect on the NMR signal of the low-barrier hydrogen bond in a transition-state analog complex of chymotrypsin.

The participation of a low-barrier hydrogen bond (LBHB) in the mechanism of action of chymotrypsin introduces a new role for Asp 102 and His 57 in catalysis [C. S. Cassidy, J. Lin, and P. A. Frey (1997) Biochemistry 36, 4576-4584]. It is postulated that the LBHB increases the basicity of His 57-N(epsilon2) in the transition state, thereby facilitating the abstraction of a proton from Ser 195, and stabilizes the tetrahedral intermediate in the acylation step. Evidence for this mechanism includes the downfield chemical shift of the proton bridging His 57 and Asp 102 in transition-state analog complexes and the low deuterium fractionation factors for this proton in the same complexes. We present additional spectroscopic evidence supporting the assignment of an LBHB between His 57 and Asp 102. The tetrahedral addition complex between Ser 195 of chymotrypsin and N-acetyl-l-leucyl-l-phenylalanyl trifluoromethylketone is regarded as a close structural analog of a tetrahedral intermediate. The deuterium NMR signal for the downfield deuteron bridging His 57 and Asp 102 in D(2)O has now been observed as a broad band centered at 17.8 +/- 0.5 ppm. The proton NMR signal in H(2)O is centered at 18.9 +/- 0.05 ppm. The two signals are clearly separated corresponding to a deuterium isotope effect of Delta[delta(H) - delta(D)] = 1.1 +/- 0.5 ppm. Deuterium isotope effects in this range are characteristic of LBHBs, and this observation provides further support for the assignment of the proton bridging His 57 and Asp 102 in transition-state analog complexes as an LBHB.

Binding Sites↗
PubMed2000

Depression of quasiparticle density of states at zero energy in la1. 9Sr0.1Cu1-xZnxO (4)

We have measured low-temperature specific heat C(T,H) of La 1.9Sr 0. 1Cu 1-xZn xO (4) ( x = 0, 0.01, and 0.02) in both zero and applied magnetic fields. A pronounced dip of C/T below 2 K was observed in Zn-doped samples, which is absent in the nominally clean one. If the origin of the dip in C/T is electronic, the quasiparticle density of states N(E) in Zn-doped samples may be depressed below a small energy scale E0. The present data can be well described by the model N(E) = N(0)+alphaE(1/2), with a nonzero N(0) and positive alpha. Magnetic fields depress N(0) and lead to an increase in E0, while leaving the energy dependence of N(E) unchanged. This novel depression of N(E) below E0 in impurity-doped cuprates cannot be reconciled with the semiclassical self-consistent approximation model. Discussions in the framework based on the nonlinear sigma model field theory and other possible explanations are presented.

Journal Article↗
PubMed2000

Genomewide scan for prostate cancer-aggressiveness loci.

The aggressiveness of prostate cancer (PCa) varies widely: some tumors progress to invasive, potentially life-threatening disease, whereas others stay latent for the remainder of an individual's lifetime. The mechanisms resulting in this variability are not yet understood, but they are likely to involve both genetic and environmental influences. To investigate genetic factors, we conducted a genomewide linkage analysis of 513 brothers with PCa, using the Gleason score, which reflects tumor histology, as a quantitative measure of PCa aggressiveness. To our knowledge, this is the first time that a measure of PCa aggressiveness has been directly investigated as a quantitative trait in a genomewide scan. We employed a generalized multipoint Haseman-Elston linkage-analysis approach that regresses the mean-corrected cross product between the brothers' Gleason scores on the estimated proportion of alleles shared by brothers identical by descent at each marker location. Our results suggest that candidate regions on chromosomes 5q, 7q, and 19q give evidence for linkage to PCa-aggressiveness genes. In particular, the strongest signals detected in these regions were at the following markers (with corresponding P values): for chromosome 5q31-33, between markers D5S1480 and D5S820 (P=.0002); for chromosome 7q32, between markers D7S3061 and D7S1804 (P=.0007); and, for chromosome 19q12, at D19S433 (P=.0004). This indicates that one or more of these candidate regions may contain genes that influence the progression of PCa from latent to invasive disease. Identification of such genes would be extremely valuable for elucidation of the mechanism underlying PCa progression and for determination of treatment in men in whom this disease has been diagnosed.

Adult↗
PubMed2000

ATM phosphorylates p95/nbs1 in an S-phase checkpoint pathway.

The rare diseases ataxia-telangiectasia (AT), caused by mutations in the ATM gene, and Nijmegen breakage syndrome (NBS), with mutations in the p95/nbs1 gene, share a variety of phenotypic abnormalities such as chromosomal instability, radiation sensitivity and defects in cell-cycle checkpoints in response to ionizing radiation. The ATM gene encodes a protein kinase that is activated by ionizing radiation or radiomimetic drugs, whereas p95/nbs1 is part of a protein complex that is involved in responses to DNA double-strand breaks. Here, because of the similarities between AT and NBS, we evaluated the functional interactions between ATM and p95/nbs1. Activation of the ATM kinase by ionizing radiation and induction of ATM-dependent responses in NBS cells indicated that p95/nbs1 may not be required for signalling to ATM after ionizing radiation. However, p95/nbs1 was phosphorylated on serine 343 in an ATM-dependent manner in vitro and in vivo after ionizing radiation. A p95/nbs1 construct mutated at the ATM phosphorylation site abrogated an S-phase checkpoint induced by ionizing radiation in normal cells and failed to compensate for this functional deficiency in NBS cells. These observations link ATM and p95/nbs1 in a common signalling pathway and provide an explanation for phenotypic similarities in these two diseases.

Ataxia Telangiectasia↗
PubMed2000

Human glucose-6-phosphate dehydrogenase (G6PD) gene transforms NIH 3T3 cells and induces tumors in nude mice.

The main physiological function of glucose-6-phosphate dehydrogenase (G6PD) is to produce NADPH and ribose 5-phosphate, which are essential for reductive biosynthesis and nucleic acid synthesis. In normal cells, G6PD expression is tightly controlled; however, in many tumors, regulation of its expression is altered, resulting in a significant increase in G6PD activity. To investigate the potential role of G6PD in tumorigenesis, we transfected NIH 3T3 cells with human G6PD cDNA. Cells overexpressing G6PD showed altered cell morphology and exhibited tumorigenic properties. In contrast to the control cells or cells transfected with mutated G6PD cDNA, G6PD-overexpressing cells were not contact inhibited and exhibited anchorage-independent growth. They divided more quickly and induced rapidly growing, large fibrosarcomas in nude mice. Moreover, the induced tumorigenic properties were positively correlated with the level of G6PD activity. Interestingly, treatment with buthionine SR-sulfoximine (BSO), a glutathione depletion agent, decreased the colony-forming efficiency of G6PD-overexpressing cells in soft agar, which implicates that alteration of the redox balance may be involved in G6PD-induced tumorigenesis. A comparative analysis of the expression level of G6PD in a variety of human cancer cell lines was also performed. Northern- and Western-blot analyses revealed that G6PD was particularly overexpressed in human esophageal cancer cell lines. Our observations indicate that G6PD may act as a potential oncogene, whose overexpression plays a critical role in neoplastic transformation.

3T3 Cells↗
PubMed2000

Functional alpha-fragment of beta-galactosidase can be expressed from the mobile group I intron PpLSU3 embedded in yeast pre-ribosomal RNA derived from the chromosomal rDNA locus.

PpLSU3, a mobile group I intron found in the ribo-somal RNA genes of Physarum polycephalum, encodes the I-PpoI homing endonuclease. This enzyme represents one of the rare cases in nature where a protein is expressed from an RNA polymerase I transcript. Our previous results showed that the full length intron, but not a further processed species, is the messenger for I-PpoI, implying a role of the untranslated region (UTR) in gene expression. To study the function of the 3'-UTR in expression of the endonuclease and in splicing of the intron, we replaced the I-PpoI gene in PpLSU3 with the gene for the alpha-fragment of Escherichia coli beta-galactosidase, and then integrated this chimeric intron into all the chromosomal rDNA repeats of yeast. The resulting cells synthesized functional alpha-fragment, as evidenced by a complementation assay analogous to that used in E.coli. The beta-galactosidase activity thus provides an unusual and potentially valuable readout for Pol I transcription from chromosomal rDNA. This is the first example in which a eucaryotic homing endonuclease gene has been successfully replaced by a heterologous gene. Using deletion mutagenesis and a novel randomization approach with the alpha-fragment as a reporter, we found that a small segment of the 3'-UTR dramatically influences both splicing and protein expression.

3' Untranslated Regions↗
PubMed2000

An oral vaccine against NMDAR1 with efficacy in experimental stroke and epilepsy.

The brain is generally considered immunoprivileged, although increasing examples of immunological responses to brain antigens, neuronal expression of major histocompatibility class I genes, and neurological autoimmunity have been recognized. An adeno-associated virus (AAV) vaccine generated autoantibodies that targeted a specific brain protein, the NR1 subunit of the N-methyl-D-aspartate (NMDA) receptor. After peroral administration of the AAV vaccine, transgene expression persisted for at least 5 months and was associated with a robust humoral response in the absence of a significant cell-mediated response. This single-dose vaccine was associated with strong anti-epileptic and neuroprotective activity in rats for both a kainate-induced seizure model and also a middle cerebral artery occlusion stroke model at 1 to 5 months following vaccination. Thus, a vaccination strategy targeting brain proteins is feasible and may have therapeutic potential for neurological disorders.

Administration, Oral↗
PubMed2000

Physical, chemical, and biological evaluations of P760: a new gadolinium complex characterized by a low rate of interstitial diffusion.

An original gadolinium chelate, termed P760, which diffuses through the vascular endothelium but at a much lower rate than nonspecific agents (NSA), is described. P760 is a gadolinium macrocyclic compound based on a DOTA structure that is substituted by hydrophilic bulky groups branched on the amino-carboxylic residues. The molecular weight is 5293, and the molecular volume, measured by light scattering, is 30 times higher (11.5 nm3) than that of gadolinium (Gd)-DOTA (0.38 nm3). The increase in molecular volume and weight has two consequences: a) higher relaxivity (r1; 24.7 mM-1.s-1 compared with 3.4 mM-1.s-1 for Gd-DOTA at 20 Mhz, 37 degrees C); and b) a lengthening of its transport rate through the endothelium. P760 presents a peculiar pharmacokinetic profile: at early times post injection, the blood concentrations are higher than those of Gd-DOTA, but after 20 minutes, the blood concentrations are equal for the two compounds. The body clearances of the products are identical (i.e., glomerular filtration rate). P760 molecules are large enough to have a restricted diffusion through the endothelium but, conversely, small enough to pass freely through the glomerular membrane. This limited extravasation has been observed in rabbits by magnetic resonance angiography or in investigations of tumor permeability. Further experimental imaging studies are needed to define the clinical interest of such properties.

Animals↗
PubMed2000

Expression and localization of rab escort protein isoforms in parotid acinar cells from rat.

Rab proteins are geranylgeranylated on their carboxyl terminal cysteine motifs by geranylgeranyltransferase II (GGTase). Rab escort protein (REP) is required to present Rab proteins to GGTase. REP may remain bound to newly isoprenylated Rab proteins and present them to their target membrane. Other studies have shown that Rab proteins cycle between the membrane and cytosolic compartments and that cytosolic Rab proteins are complexed with rab-GDI. In the present study, we examined the expression and localization of REP isoforms in parotid acinar cells. Although both REP isoforms, REP-1 and REP-2, were detected in parotid cytosol, REP-2 was the predominant isoform. Subcellular fractionation revealed that approximately 42% of cellular REP-2 is membrane-associated. REP-2 was partially removed from parotid membranes with 1 M NaCl or Na(2)CO(3), indicating that REP-2 is a peripheral membrane protein. Membrane-associated REP-2 did not colocalize with Rab3D on secretory granule membranes. However, density gradient centrifugation revealed that membrane-associated REP-2 and Rab3D colocalize on low- and high-density membrane fractions in parotid acinar cells. Isoproterenol, an agent which induces amylase release from parotid glands, caused a shift in both REP-2 and Rab3D to less dense membrane fractions. When acinar cell cytosol was fractionated by gel filtration chromatography, Rab3D eluted exclusively with REP, not rab-GDI. In contrast, Rab1B and Rab5 eluted with both REP and Rab-GDI. Colocalization of Rab3D and REP-2 on acinar cell membranes suggests that REP-2 plays a role in delivering Rab3D to parotid membranes and may regulate guanine nucleotide binding to membrane-associated Rab3D. In addition, unlike other Rab proteins, cytosolic Rab3D appears to associate exclusively with REP, not rab-GDI in parotid acinar cells.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Preliminary screening of some traditional Zulu medicinal plants for antineoplastic activities versus the HepG2 cell line.

Aqueous and methanol extracts of nine traditional Zulu medicinal plants, Cissus quandrangularis L., Cyphostemma flaviflorum (Sprague) Descoings, Cyphostemma lanigerum (Harv.) Descoings ex Wild & Drum, Cyphostemma natalitium (Szyszyl.) J. v. d. Merwe, Cyphostemma sp., Rhoicissus digitata (L. F.) Gilg & Brandt, Rhoicissus rhomboidea (E. Mey. Ex harv.) Planch, Rhoicissus tomentosa (Lam.) Wild & Drum, R. tridentata (L. F.) Wild & Drum and Rhoicissus tridentata (L. F.) Wild & Drum subsp. cuneifolia (Eckl. & Zeyh.) N. R. Urton, all belonging to the Vitaceae family, were evaluated to determine their therapeutic potentials as antineoplastic agents. The antiproliferative activity in vitro against HepG2 cells was determined. Twenty-two of the twenty-seven crude plant extracts showed activities ranging from 25% to 97% inhibition of proliferation when compared with the control which showed no inhibitory activity. Higher degrees of growth inhibition were found in aqueous root extracts in comparison with the methanol extracts of the same plant parts. The results show potential antineoplastic activity, indicating some scientific validation for traditional usage.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Constitutive activation of stat 3 oncogene product in human ovarian carcinoma cells.

OBJECTIVE: Stat 3 functions in transducing signals from the cell's surface to its nucleus and activation of gene transcription. Aberrations of Stat 3 in breast cancer have raised the possibility of its contribution to oncogenesis. Our goal was to examine ovarian cancer cell lines to determine whether Stat 3 plays a relevant role in ovarian carcinogenesis. METHODS: Protein lysates were extracted from normal ovarian surface epithelial cells and malignant cells. Western blotting techniques were performed with phosphorylation-independent or phosphorylation-specific Stat 3 (tyrosine 705) antibody. Confirmation of Stat 3 activation was determined by a luciferase reporter driven by a promoter containing Stat 3-specific binding sites. Bcl-x(L) and cyclin D(1) were also analyzed by Western blotting. RESULTS: MDAH 2774, OV-1063, Caov-3, and O.C. 22819 expressed high levels of phosphorylated Stat 3. In contrast, A2780 and normal ovarian surface epithelial cells had little Stat 3 phosphorylation recognized. Confirmation of persistent activation of Stat 3 activity was shown by transfection of cells with a Stat 3 luciferase reporter. Potential downstream mediators of Stat 3 including Bcl-x(L) and cyclin D(1) were also evaluated. In cells expressing activated Stat 3, high levels of both Bcl-x(L) and cyclin D(1) were detected, whereas in A2780 cells, which did not express activated Stat 3, only low levels of Bcl-x(L) and cyclin D(1) were expressed. CONCLUSIONS: Constitutive activation of Stat 3 is present in ovarian cancer lines but not in normal ovarian surface epithelial cells. Activation of Stat 3 is a common event during oncogenic transformation upstream to both Bcl-x(L) and cyclin D(1). The relationship of this aberrancy of ovarian carcinoma harboring activated Stat 3 deserves further investigation.

Cell Transformation, Neoplastic↗