Biomedical subjects

J Ostrowski

Publications and source records attributed to J Ostrowski.

At least 19 recordsLinked to original sources

PubMed2006

Functional categories of TP53 mutation in colorectal cancer: results of an International Collaborative Study.

BACKGROUND: Loss of TP53 function through gene mutation is a critical event in the development and progression of many tumour types including colorectal cancer (CRC). In vitro studies have found considerable heterogeneity amongst different TP53 mutants in terms of their transactivating abilities. The aim of this work was to evaluate whether TP53 mutations classified as functionally inactive (< or=20% of wildtype transactivation ability) had different prognostic and predictive values in CRC compared with mutations that retained significant activity. MATERIALS AND METHODS: TP53 mutations within a large, international database of CRC (n = 3583) were classified according to functional status for transactivation. RESULTS: Inactive TP53 mutations were found in 29% of all CRCs and were more frequent in rectal (32%) than proximal colon (22%) tumours (P < 0.001). Higher frequencies of inactive TP53 mutations were also seen in advanced stage tumours (P = 0.0003) and in tumours with the poor prognostic features of vascular (P = 0.006) and lymphatic invasion (P = 0.002). Inactive TP53 mutations were associated with significantly worse outcome only in patients with Dukes' stage D tumours (RR = 1.71, 95%CI 1.25-2.33, P < 0.001). Patients with Dukes' C stage tumours appeared to gain a survival benefit from 5-fluorouracil-based chemotherapy regardless of TP53 functional status for transactivation ability. CONCLUSIONS: Mutations that inactivate the transactivational ability of TP53 are more frequent in advanced CRC and are associated with worse prognosis in this stage of disease.

Adenocarcinoma↗

PubMed2006

Editing of hnRNP K protein mRNA in colorectal adenocarcinoma and surrounding mucosa.

The heterogeneous nuclear ribonucleoprotein K (hnRNP K) protein is an RNA-binding protein involved in many processes that compose gene expression. K protein is upregulated in the malignant processes and has been shown to modulate the expression of genes involved in mitogenic responses and tumorigenesis. To explore the possibility that there are alternative isoforms of K protein expressed in colon cancer, we amplified and sequenced K protein mRNA that was isolated from colorectal cancers as well as from normal tissues surrounding the tumours. Sequencing revealed a single G-to-A base substitution at position 274 that was found in tumours and surrounding mucosa, but not in individuals that had no colorectal tumour. This substitution most likely reflects an RNA editing event because it was not found in the corresponding genomic DNAs. Sequencing of RNA from normal colonic mucosa of patients with prior resection of colorectal cancer revealed only the wild-type K protein transcript, indicating that G274A isoform is tumour related. To our knowledge, this is the first example of an RNA editing event in cancer and its surrounding tissue, a finding that may offer a new diagnostic and treatment marker.

Biomarkers, Tumor↗

PubMed2005

A randomised comparison of treosulfan and carboplatin in patients with ovarian cancer: a study by the Scottish Gynaecological Cancer Trials Group (SGCTG).

The management of older and unfit women with advanced ovarian cancer requires post-operative chemotherapy but many of these patients are not suitable for high-dose cisplatin-based regimes. Carboplatin has been an easier alternative and can be given in the ambulatory setting. Historical data suggests that oral alkylating agents to be just effective with similar efficacy. In this study we have compared platinum-based carboplatin to the alkylating agent treosulfan in a population unfit to receive high-dose cisplatin. The trial randomised patients to either intravenous carboplatin or treosulfan as single agent. The trial was stopped prematurely after the interim analysis showed improved survival and response rates in the carboplatin arm. We conclude that carboplatin is a safe and effective drug in a population that is unfit for high-dose cisplatin. Treosulfan showed limited activity but may be considered along with other oral drugs in limited circumstances. With the exception of myelosuppression, toxicity was mild in both arms. Carboplatin remains the gold standard in this older and less fit group of patients.

Aged↗

PubMed2005

Expression of pendrin in benign and malignant human thyroid tissues.

The Pendred syndrome gene (PDS) encodes a transmembrane protein, pendrin, which is expressed in follicular thyroid cells and participates in the apical iodide transport. Pendrin expression has been studied in various thyroid neoplasms by means of immunohistochemistry (IHC), Western blot and RT-quantitative real-time PCR. The expression was related to the functional activity of the thyroid tissue. Follicular cells of normal, nodular goitre and Graves' disease tissues express pendrin at the apical pole of the thyrocytes. In follicular adenomas, pendrin was detected in cell membranes and cytoplasm simultaneously in 10 out of 15 cases. Pendrin protein was detected in 73.3 and 76.7% of the follicular (FTC) and papillary (PTC) thyroid carcinomas, respectively, where pendrin was solely localised inside the cytoplasm. An extensive intracellular immunostaining of pendrin was observed in six out of 11 (54.5%) of positive FTCs and 19 out of 23 (82%) of PTCs. Focal reactivity was detected in one follicular- and three papillary carcinomas, whereas pendrin protein was absent in three of 15 FTC and four of 30 PTC; mRNA of pendrin was detected in 92.4% of thyroid tumours. The relative mRNA expression of pendrin was lower in cancers than in normal thyroid tissues (P<0.001). The pendrin protein level was found to parallel its mRNA expression, which was not, however, related to the tumour size and tumour stage. In conclusion, pendrin is expressed in the majority of differentiated thyroid tumours with high individual variability but its targeting to the apical cell membrane is affected.

Amino Acid Sequence↗

PubMed2004

The ability of Azolla caroliniana to remove heavy metals (Hg(II), Cr(III), Cr(VI)) from municipal waste water.

The aim of this paper was to investigate the capacity of a small water fern, Azolla caroliniana Willd. (Azollaceae), to purify waters polluted by Hg and Cr. Many plants are capable of accumulating heavy metals (called hyperaccumulators) and one of them is the water fern A. caroliniana. During 12 days of the experiment the fern was grown on the nutrient solution containing Hg2+, Cr3+ and CrO4(2-) ions, each in a concentration 0.1, 0.5 and 1.0 mg dm(-3). The presence of these ions caused a 20-31% inhibition of A. caroliniana growth, the highest in the presence of Hg(II) ions, in comparison to the control. After day 12 of the experiment, metal contents the solution decreased to 0-0.25 mg dm(-3), and this decrease comprised between 74 (Cr3+ 1.0 mg dm(-3) treatment) and 100% (CrO4(2-) 0.1 mg dm(-3) treatment). The fern took a lesser quantity of the metals from 0.1 mg dm(-3) treatments compared to 0.5 and 1.0 mg dm(-3) treatments. In the A. caroliniana tissues the concentration of heavy metals under investigation ranged from 71 to 964 mg kg(-1) dm; the highest level being found for Cr(III) containing nutrient solution.

Biomass↗

PubMed2004

Sclerotherapy with bleomycin for recurrent massive inguinal lymphoceles following partial vulvectomy and bilateral lymphadenectomy-Case report and literature review.

BACKGROUND: Formation of lymphoceles following radical vulvectomy presents a formidable problem that is associated with high degree of morbidity. A variety of approaches have been described in the literature to treat this condition. CASE: An 82-year-old woman developed massive inguinal lymphoceles following partial vulvectomy and inguinal lymphadenectomy for cancer vulva. The lymphoceles involved wide surface areas extending to both flanks, and accumulation of lymph was very rapid at a rate of 1 l daily. The condition failed to respond to continuous drainage and compression for 6 weeks, but responded quickly to sclerotherapy using bleomycin without any significant side effects. CONCLUSION: Intracavitary bleomycin could be used safely and effectively in huge rapidly accumulating lymphoceles.

Aged↗

PubMed2003

Nuclear shift of hnRNP K protein in neoplasms and other states of enhanced cell proliferation.

The heterogeneous nuclear ribonucleoprotein K (hnRNP K), is a ubiquitously expressed protein that interacts with signal transducers, proteins that modulate gene expression and selective RNA and DNA motifs. K protein is modified in response to extracellular signals and directly regulates rates of transcription and translation. We used serum-treated hepatocyte culture, liver after partial hepatectomy and hepatic neoplasms as systems to compare expression, subcellular distribution and tyrosine phosphorylation of K protein in quiescent and dividing cells. The results show that expression of K protein mRNA was increased in states of enhanced proliferation. Levels of nuclear K protein were also higher in proliferating compared to resting cells. In contrast, levels of cytoplasmic K protein were the same or lower in dividing compared to quiescent cells. States of enhanced proliferation were also associated with increased levels of K protein tyrosine phosphorylation. Nuclear shift of K protein in dividing cells may reflect involvement of K protein in signalling multiple events that regulate expression of genes in proliferating cells.

Cell Culture Techniques↗

PubMed2003

Do altering in ornithine decarboxylase activity and gene expression contribute to antiproliferative properties of COX inhibitors?

Two isoforms of cyclooxygenase (COX) participate in growth control; COX-1 is constitutively expressed in most cells, and COX-2 is an inducible enzyme in response to cellular stimuli. An induction of COX-2 found in neoplastic tissues results in increased cell growth, inhibition of apoptosis, activation of angiogenesis, and decreased immune responsiveness. Although both COX-1 and COX-2 inhibitors are suppressors of cell proliferation and appear to be chemopreventive agents for tumorigenesis, the molecular mechanisms mediating antiproliferative effect of COX inhibitors are still not well defined. This study contrasts and compares the effects of aspirin and celecoxib, inhibitors of COX-1 and COX-2, in rat hepatoma HTC-IR cells. The following were assessed: cell proliferation and apoptosis, ornithine decarboxylase (ODC) activity, and pattern expression of three immediate-early genes, c-myc, Egr-1, and c-fos. We have shown that the treatment of hepatocytes in vitro with the selective COX-2 inhibitor, celecoxib, was associated with induction of apoptosis and complete inhibition of cellular proliferation. Aspirin exhibited a small antiproliferative effect that was not associated with apoptosis. Treatment with celecoxib produced dose- and time-dependent decrease in ODC activity. In addition, at higher drug concentration the decrease in ODC activity was greater in proliferating than in resting cells. Much lesser inhibitory effect on ODC activity was observed in aspirin-treated cells. The two COX inhibitors did not change c-myc expression, significantly decreased the expression of Egr-1, and differentially altered expression of c-fos; aspirin did not change, but celecoxib dramatically decreased the levels of c-fos-mRNA. Our study revealed that celecoxib and aspirin share the ability to inhibit ODC activity and alter the pattern of immediate-early gene expression. It seems that some of the observed effects are likely to be related to COX-independent pathways. The precise mechanisms of action of COX inhibitors should be defined before using these drugs for cancer chemopreventive therapy.

Animals↗

PubMed2001

The retinoic acid receptor antagonist, BMS453, inhibits normal breast cell growth by inducing active TGFbeta and causing cell cycle arrest.

We have previously shown that a retinoic acid receptor (RAR) antagonist BMS453, which does not activate RAR-dependent gene transcription in breast cells, inhibits normal breast cell growth. In this study we have investigated the mechanisms by which this retinoid receptor antagonist inhibits cell growth. Both all trans retinoic acid (atRA) and BMS453 inhibited the proliferation of normal breast cell growth without significantly inducing apoptosis. Both retinoids caused a G1 block in the cell cycle with an increase in the proportion of cells in G0/G1 and a decrease in the proportion of cells in S phase. We then investigated the effects of the retinoids on molecules that regulate the G1 to S transition. These studies demonstrated that both atRA and BMS453 induce Rb hypophosphorylation and decrease CDK2 kinase activity. We then studied the effect of the retinoids on the expression of CDK inhibitors. atRA and BMS453 increased total p21 protein levels and CDK2-bound p21 protein, but did not change CDK4-bound p21. These results suggest that atRA and BMS453 increase p21, decrease CDK2 kinase activity, which in turn leads to hypophosphorylation of Rb and G1 arrest. Because transforming growth factor beta (TGFbeta) has been proposed as a mediator of retinoid-induced growth inhibition, we next investigated whether TGFbeta mediates the anti-proliferative effect of atRA and BMS453 in normal breast cells. These studies showed that atRA and BMS453 increased total TGFbeta activity by 3-5-fold. However, BMS453 increased active TGFbeta activity by 33-fold while atRA increased active TGFbeta activity by only threefold. These results suggest that BMS453 treatment induces conversion of latent TGFbeta to active TGFbeta. To investigate whether this increase in active TGFbeta mediates the anti-proliferative effects of these retinoids, a TGFbeta-blocking antibody was used in an attempt to prevent retinoid-induced growth inhibition. Results from these experiments showed that the anti-TGFbeta antibody prevented the inhibition of cell proliferation induced by BMS453, but did not prevent the inhibition of cell proliferation induced by atRA. These results demonstrate that BMS453 inhibits breast cell growth predominantly through the induction of active TGFbeta, while atRA inhibits growth through other mechanisms. These results suggest that retinoid analogs that increase active TGFbeta may be promising agents for the prevention of breast cancer.

Blotting, Western↗

PubMed2001

RACK1 protein interacts with Helicobacter pylori VacA cytotoxin: the yeast two-hybrid approach.

The VacA toxin is the major virulence factor of Helicobacter pylori. The studies on VacA intracellular expression suggest that it interacts with cytosolic proteins and that this interaction contributes significantly to vacuolization. The aim of this study was to identify the host protein(s) that interacts with the VacA protein. We used the fragments of VacA protein fused with GAL4-BD as the baits in the yeast two-hybrid approach. The yeast transformed with plasmids encoding bait proteins were screened with human gastric mucosa cDNA library, encoded C-terminal fusion proteins with GAL4-AD. Three independent His-beta-Gal-positive clones were identified in VacA-b1 screen; they matched two different lengths of cDNA encoding RACK1 protein. The specific activity of beta-galactosidase found in the yeast expressing both VacA-b1 and RACK1 fusion proteins was 12-19 times higher compared to all negative controls used. VacA is capable of binding the RACK1 in vitro as was confirmed by the pull-down assay with GST fusion VacA protein and [(35)S]Met-labeled RACK1 protein fragments.

Bacterial Proteins↗

PubMed2001

Insulin alters heterogeneous nuclear ribonucleoprotein K protein binding to DNA and RNA.

The interaction of the multimodular heterogeneous nuclear ribonucleoprotein (hnRNP) K protein with many of its protein and nucleic acid partners is regulated by extracellular signals. Acting as a docking platform, K protein could link signal-transduction pathways to DNA- and RNA-directed processes such as transcription, mRNA processing, transport, and translation. Treatment of hepatocyte culture with insulin increased K protein tyrosine phosphorylation. Insulin altered K protein interaction with RNA and DNA in vitro. Administration of insulin into mice had similar effects on K protein in liver. Coimmunoprecipitations of RNA with K protein revealed preferential in vivo K protein binding of a subset of transcripts, including the insulin-inducible c-fos mRNA. These results suggest a class of insulin pathways that signal nucleic acid-directed processes that involve K protein.

Animals↗

PubMed2001

Mutations, methylation and expression of CDKN2a/p16 gene in colorectal cancer and normal colonic mucosa.

The status of CDKN2a gene, coding for p16 and p19ARF proteins, was examined in 55 colorectal cancers. Polymerase chain reaction (PCR), single stranded conformational polymorphism and sequencing revealed 1 case of CDKN2a mutation. Methylation-specific PCR detected p16 locus methylation in 37 (73%) of 51 normal samples and 29 (53%) of 55 cancers (P=0.035). p16 transcript absence (assessed by reverse transcription-polymerase chain reaction) was noted in 10 (45%) of 22 normal samples and four (14%) of 29 cancers (P=0.012) and correlated with gene methylation (P=0.036). The decreasing frequency of p16 silencing in cancer comparing to normal mucosa does not support the postulated role of p16 in colorectal carcinogenesis.

Carrier Proteins↗

PubMed2001

Peptide analog of fibronectin that inhibits cell migration and ERK 1/2 activity.

Two analogs of the peptide mimicking the 1977-1991 C- terminal part of fibronectin have been synthesized and tested. AWLI simulated human fibronectin fragment 1977-1991, whereas AWLII hybridized to both RGD and 1977-1991 fragments. AWLI and AWLII peptides inhibited the migration of the ovarian carcinoma cell line OVP10 regardless of the presence RGD. AWLI peptide inhibited spontaneous and fibronectin-activated cell migration and ERK1/2 activity. Neither AWLI nor fibronectin induced changes in FAK proteins, as could be judged from Western blots. In conclusion, it seems that the C-terminal fragment of fibronectin inhibits ERK1/2-dependent (random) migration of ovarian carcinoma cells.

Amino Acid Sequence↗

PubMed2001

Acquired aorta-pulmonary artery fistula: diagnosis by multiple imaging modalities.

Acquired communication between the aorta and the pulmonary artery is a rare phenomenon. We describe two patients with a thoracic aortic aneurysm in whom the diagnosis of a communication with the pulmonary artery was first made on transthoracic echocardiography and then more completely elucidated by means of multiple imaging modalities: transesophageal echocardiography, epiaortic ultrasound, computed tomography, and magnetic resonance imaging. Representative images from these complementary studies are presented. A successful repair of the fistula was subsequently accomplished in both patients.

Aged↗

PubMed2001

[Postero-medial release in surgical treatment of congenital clubfeet: a comment to Turco's method based on personal experience].

Complete correction of congenital clubfeet by conservative treatment is often impossible. Surgical treatment plays a major role in treatment of this deformity. At the Department of Pediatric Orthopedics in Lublin between 1970 and 1999 1041 children (1253 feet) were treated surgically with Turco's method, in the authors' own modification. The paper presents the technically optimal procedure, the range of tendon elongation. The way the wound is closed is particularly stressed, as well as the need to achieve muscle balance, along with a description of proper post-op care. The material was analysed as a whole, although particular attention was given to three periods: 1970-1975, 1980-1985, 1990-1995. The results were assessed according to the Turco classification, the Magone classification in accordance with the injunctions of the Scientific Committee Meeting of the Pediatric Section of the Polish Orthopedic Society held in Poznan. Good and very good results were achieved in 65-67% of the cases, while satisfactory and bad results were found in 23-30% of the cases.

Adolescent↗

PubMed2000

Role of tyrosine phosphorylation in the regulation of the interaction of heterogenous nuclear ribonucleoprotein K protein with its protein and RNA partners.

The heterogeneous nuclear ribonucleoprotein K protein recruits a diversity of molecular partners and may act as a docking platform involved in such processes as transcription, RNA processing, and translation. We show that K protein is tyrosine-phosphorylated in vitro by Src and Lck. Treatment with H(2)O(2)/Na(3)VO(4), which induces oxidative stress, stimulated tyrosine phosphorylation of K protein in cultured cells and in intact livers. Tyrosine phosphorylation increased binding of Lck and the proto-oncoprotein Vav to K protein in vitro. Oxidative stress increased the association of K protein with Lck and Vav, suggesting that tyrosine phosphorylation regulates the ability of K protein to recruit these effectors in vivo. Translation-based assay showed that K protein is constitutively bound to many mRNAs in vivo. Native immunoprecipitated K protein-mRNA complexes were disrupted by tyrosine phosphorylation, suggesting that the in vivo binding of K protein to mRNA may be responsive to the extracellular signals that activate tyrosine kinases. This study shows that tyrosine phosphorylation of K protein regulates K protein-protein and K protein-RNA interactions. These data are consistent with a model in which functional interaction of K protein is responsive to changes in the extracellular environment. Acting as a docking platform, K protein may bridge signal transduction pathways to sites of nucleic acid-dependent process such as transcription, RNA processing, and translation.

HeLa Cells↗

PubMed2000

p53 protein accumulation and p53 gene mutation in colorectal cancer.

Comparison of immunohistochemical methods for detection of protein p53 accumulation and molecular techniques for analysis p53 gene mutation in colorectal cancer is presented. Thirty eight patients were included: all underwent surgery without preoperative treatment. Sex of patients, tumor localisation, macro and microscopic type of cancer and staging according to Astler-Coller and Jass classifications were evaluated. Protein p53 accumulation was detected by the streptavidin-biotin method using DO-7 (Dako) antibody. The number of cells stained were classified semiquanititatively according to a scoring system: (-)no positive cells, (+) : 10-30% positive cells, (++) : 40-70% positive cells, (+++) : >70% positive cells. For all cancer samples, exons 5 to 9 of p53 gene were amplified from isolated genomic DNA. PCR products were subjected to single standed conformational polymorphism analysis. All product were also directly sequenced on ABI PRISM 377 apparatus using fluorescent dideoxyterminators chemistry. The protein p53 accumulation was detected in 53% (20/38), whereas p53 gene mutation was seen in 55% (21/38). Among them, 15 patients (39%) with overexpression showed mutation in exon 5-8 gene p53. Discrepancies between results were noted in 29%. In conclusion, the necessity of both methods immunohistochemical and molecular is indicated for the objective evaluation of functional and structural status of p53 gene and protein.

Adult↗

PubMed2000

Treatment of mice with EGF and orthovanadate activates cytoplasmic and nuclear MAPK, p70S6k, and p90rsk in the liver.

BACKGROUND/AIMS: Although signal transduction pathways activated by EGF have been extensively studied in cultured cells, few such studies have been done in whole animals. In this study, activation of hepatic kinases, phosphatases, and DNA-binding activity of AP-1 was examined after intraperitoneal injections of either EGF or sodium orthovanadate into mice. METHODS: Cytoplasmic and nuclear proteins, extracted from isolated hepatocytes or whole liver tissue, were immunoprecipitated with either anti-ERK1/2, anti-70S6k, or anti-p90rsk antibodies and kinase activities were measured using specific substrates. Kinase protein levels was evaluated by Western blot analysis. AP-1 DNA binding activity was measured by electrophoretic mobility shift assay. RESULTS: Systemic administration of EGF induced simultaneous increase in the activities of cytoplasmic and nuclear MAPK, p70S6k, and p90rsk. MAPK and p70S6k were more potently activated in the cytosol while p90rsk activation was more pronounced in the nucleus. Orthovanadate also activated these kinases but to a much lesser degree than EGF. In vitro phosphatase assays showed that neither EGF nor orthovanadate induced measurable changes in phosphatase activities. EGF, but not orthovanadate, activated nuclear AP-1 DNA-binding activity in intact liver, indicating that activation of MAPK, p70S6k, and p90rsk by orthovanadate is not sufficient to activate this transcription factor. CONCLUSION: These observations provide groundwork for future studies to examine the role of EGF-induced kinase cascades and transcription factors in liver regeneration and other growth factor-mediated hepatic processes.

Animals↗