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C A Moskaluk

Publications and source records attributed to C A Moskaluk.

At least 19 recordsLinked to original sources
PubMed2006

Evidence for functional ATP-sensitive (K(ATP)) potassium channels in human and equine articular chondrocytes.

OBJECTIVE: Chondrocytes are highly sensitive to variations in extracellular glucose and oxygen levels in the extracellular matrix. As such, they must possess a number of mechanisms to detect and respond to alterations in the metabolic state of cartilage. In other organs such as the pancreas, heart and brain, such detection is partly mediated by a family of potassium channels known as K(ATP) (adenosine 5'-triphosphate-sensitive potassium) channels. Here we investigate whether chondrocytes too express functional K(ATP) channels, which might, potentially, serve to couple metabolic state with cell activity. METHODS: Immunohistochemistry was used to explore K(ATP) channel expression in equine and human chondrocytes. Biophysical properties of equine chondrocyte K(ATP) channels were investigated with patch-clamp electrophysiology. RESULTS: Polyclonal antibodies directed against the K(ATP) Kir6.1 subunit revealed high levels of expression in human and equine chondrocytes mainly in superficial and middle zones of normal cartilage. Kir6.1 was also detected in superficial chondrocytes in osteoarthritic (OA) cartilage. In single-channel electrophysiological studies of equine chondrocytes, we found K(ATP) channels to have a maximum unitary conductance of 47 +/- 9 pS (n=5) and a density of expression comparable to that seen in excitable cells. CONCLUSION: We have shown, for the first time, functional K(ATP) channels in chondrocytes. This suggests that K(ATP) channels are involved in coupling metabolic and electrical activities in chondrocytes through sensing of extracellular glucose and intracellular adenosine triphosphate (ATP) levels. Altered K(ATP) channel expression in OA chondrocytes may result in impaired intracellular ATP sensing and optimal metabolic regulation.

Adenosine Triphosphate↗
PubMed2006

Knockdown of Sox4 expression by RNAi induces apoptosis in ACC3 cells.

Microarray RNA gene expression profiling analysis has shown that Sox4 (Sry-related high mobility group (HMG) box 4) is one of the most upregulated genes in adenoid cystic carcinoma (ACC), relative to non-neoplastic tissue of origin. Here, we show that Sox4 protein is similarly upregulated in ACC by immunohistochemistry of 28 primary cancers and 20 normal tissues. To elucidate the functional significance of these findings, RNA interference (RNAi)-mediated RNA silencing was used to downregulate Sox4 expression in the ACC-derived cell line, ACC3. With confirmed knockdown of Sox4 protein, cell viability was reduced by 51%, with a corresponding increase of apoptosis to 85% as compared to 12% in controls. Apoptosis was confirmed by cell morphology, DNA fragmentation and flow cytometry. Cells could be rescued from the proapoptotic effects of Sox4 RNAi by co-transfection with a construct expressing functional Sox4. Microarray gene expression profiling of RNAi knockdown experiments shows that downregulation of Sox4-modulated expression of critical genes involved in apoptosis and cell cycle control. Overall, our findings suggest that Sox4 contributes to the malignant phenotype of ACC cells by promoting cell survival.

Apoptosis↗
PubMed2006

Overexpression of CEBPbeta correlates with decreased TFF1 in gastric cancer.

CCAAT element binding protein beta (C/EBPbeta) is an important regulator of cell growth, differentiation and in promoting tumor invasiveness. C/EBPbeta is located on chromosome 20q, which is amplified in many solid tumors including gastric cancers (GC). We sought to characterize the status of C/EBPbeta expression in GCs, which was recently found to repres TFF1 gene. Microarray analysis revealed overexpression of C/EBPbeta in 25 of 27 (93%) GC when compared to 12 normal gastric tissue samples. RT-PCR analysis confirmed the overexpression of C/EBPbeta transcripts in 54 of 59 (91%) GC. In total, 15 of 18 gastric tumors exhibited at least fivefold higher C/EBPbeta transcript levels compared to their corresponding adjacent normal gastric tissue samples. Moreover, immunohistochemistry analysis demonstrated increased nuclear staining of C/EBPbeta in 10 of 13 GC and at least fourfold overexpression of C/EBPbeta in three primary GC compared to adjacent normal gastric tissue. Furthermore, a striking correlation of decreased TFF1 expression with increased C/EBPbeta was observed in the gastric tumors studied. Microarray analysis demonstrated a loss of TFF1 expression in all 27 GC cases examined, of which 25 exhibited high C/EBPbeta expression compared to normal gastric tissue. RT-PCR analysis revealed loss of TFF1 expression in 56 of 59 gastric tumors in which 54 of these tumors exhibited overexpression of C/EBPbeta. Immunohistochemical analysis revealed overexpression of C/EBPbeta in 10 of 13 gastric tumors that exhibited low expression of TFF1 at the protein level. Thus, overexpression of the transcription factor C/EBPbeta in the majority of GCs is a novel finding.

CCAAT-Enhancer-Binding Protein-beta↗
PubMed2004

Establishing a tumour bank: banking, informatics and ethics.

The six divisions of the Cooperative Human Tissue Network in the USA bank and distribute tens of thousands of tissue specimens to researchers annually. Major operational concerns include: maintaining tissue integrity, managing informatics, and protecting patient confidentiality. Increasing molecular genetics testing is also resulting in an increased demand for high-quality nucleic acids.

Confidentiality↗
PubMed2001

Molecular classification of human carcinomas by use of gene expression signatures.

Classification of human tumors according to their primary anatomical site of origin is fundamental for the optimal treatment of patients with cancer. Here we describe the use of large-scale RNA profiling and supervised machine learning algorithms to construct a first-generation molecular classification scheme for carcinomas of the prostate, breast, lung, ovary, colorectum, kidney, liver, pancreas, bladder/ureter, and gastroesophagus, which collectively account for approximately 70% of all cancer-related deaths in the United States. The classification scheme was based on identifying gene subsets whose expression typifies each cancer class, and we quantified the extent to which these genes are characteristic of a specific tumor type by accurately and confidently predicting the anatomical site of tumor origin for 90% of 175 carcinomas, including 9 of 12 metastatic lesions. The predictor gene subsets include those whose expression is typical of specific types of normal epithelial differentiation, as well as other genes whose expression is elevated in cancer. This study demonstrates the feasibility of predicting the tissue origin of a carcinoma in the context of multiple cancer classes.

Carcinoma↗
PubMed2001

Analysis of gene expression identifies candidate markers and pharmacological targets in prostate cancer.

Detection, treatment, and prediction of outcome for men with prostate cancer increasingly depend on a molecular understanding of tumor development and behavior. We characterized primary prostate cancer by monitoring expression levels of more than 8900 genes in normal and malignant tissues. Patterns of gene expression across tissues revealed a precise distinction between normal and tumor samples, and revealed a striking group of about 400 genes that were overexpressed in tumor tissues. We ranked these genes according to their differential expression in normal and cancer tissues by selecting for highly and specifically overexpressed genes in the majority of cancers with correspondingly low or absent expression in normal tissues. Several such genes were identified that act within a variety of biochemical pathways and encode secreted molecules with diagnostic potential, such as the secreted macrophage inhibitory cytokine, MIC-1. Other genes, such as fatty acid synthase, encode enzymes known as drug targets in other contexts, which suggests new therapeutic approaches.

Adenocarcinoma↗
PubMed2001

Inactivation of the E-cadherin gene in sporadic diffuse-type gastric cancer.

Loss of the cell adhesion molecule E-cadherin has been observed in a variety of human carcinomas, and germline E-cadherin mutations have been found in several familial cases of diffuse gastric cancer. We sought to determine the prevalence and nature of E-cadherin alterations in "sporadic" gastric carcinomas. We performed comprehensive sequencing of the coding region, loss of heterozygosity (LOH) analysis, and immunohistochemical protein expression determination on 40 sporadic gastric adenocarcinomas. In total, 7 of 25 diffuse-type cancers harbored genetic alterations in the E-cadherin gene. Novel mutations predicted to significantly compromise protein function were found within 4 of these cancers, 2 of which harbored alterations resulting in biallelic inactivation of the gene product. Three diffuse cancers failed to amplify Exon 8 of E-cadherin, suggesting the presence of a homozygous abnormality. Notably, one germline E-cadherin mutation was also identified within these "sporadic" diffuse cancers. Significant gene mutations were not found in the 14 intestinal-type or histologically mixed cancer. Immunohistochemistry revealed aberrant or negative protein expression in seven diffuse-type tumors, four of which correlated with the genetic alterations. Both diffuse and intestinal-type tumors exhibited low rates of LOH, suggesting that allelic loss at the locus is not a common mechanism for E-cadherin inactivation during gastric tumorigenesis. Our observations suggest that inactivation of the E-cadherin gene occurs only in a subset of diffuse-type gastric cancers, as the majority of cases did not contain genetic alterations or identifiable protein abnormalities. Germline E-cadherin alterations, although rare, may underlie some diffuse gastric cancer cases that have important biologic and practical implications

Adenocarcinoma↗
PubMed2001

Genetic differences between adenocarcinomas arising in Barrett's esophagus and gastric mucosa.

BACKGROUND & AIMS: Barrett adenocarcinoma (BA+) and gastric adenocarcinoma comprise a related group of neoplasms that nevertheless have some distinct clinicopathologic characteristics. This study aimed at defining critical molecular abnormalities that may underlie differences between BA+ and gastric adenocarcinomas. METHODS: We used comparative genomic hybridization for the analyses of 34 xenografts of adenocarcinomas that arose from esophageal or gastric origin. RESULTS: All tumors, except one, exhibited DNA copy number alterations. Losses in 4q and 14q and gains at 2p and 17q were more frequent in proximal (esophageal, gastroesophageal junction [GEJ], and cardia) tumors than in distal (body and antrum) tumors (P <or= 0.050). These changes were significantly higher in BA+ compared with distal tumors (P <or= 0.040). In addition, losses in 5q and gains at 20q were significantly higher in BA+ than in distal cancers (P <or= 0.040). Losses in 5q and 8p and gains at 2q, 6p, 12p, and 20q were significantly more frequent in BA+ tumors (P <or= 0.050) than in GEJ and cardiac tumors without associated Barrett's esophagus. Additionally, losses in 14q, which were common in proximal tumors, were more often seen in BA+ (P = 0.100) than in other proximal tumors. CONCLUSIONS: Although these adenocarcinomas share some common genetic alterations, the differences in the DNA copy numbers in BA+ cases suggest that unique genetic alterations may be involved in these cancers' development.

Adenocarcinoma↗
PubMed2001

Antibody blockade of ICAM-1 and VCAM-1 ameliorates inflammation in the SAMP-1/Yit adoptive transfer model of Crohn's disease in mice.

BACKGROUND & AIMS: Integrins (alpha(4) and beta(2)) and their endothelial ligands vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) play key roles in leukocyte recruitment to areas of inflammation. ICAM-1 and VCAM-1 are expressed in inflamed intestinal tissues. This study investigates a possible causative role of adhesion molecules ICAM-1, VCAM-1, and alpha(4) integrins in mediating the inflammatory response in a murine model of Crohn's disease (CD). METHODS: CD4+ mesenteric lymph node cells from SAMP-1/Yit donor mice were adoptively transferred into major histocompatibility complex-matched severe combined immunodeficiency disease mice. Six weeks later, these mice were left untreated or treated for 3 days with monoclonal antibodies (mAbs) to ICAM-1, VCAM-1, or both, and alpha(4), or both ICAM-1 and alpha(4), dexamethasone, or nonblocking isotype control antibodies. On day 4 after treatment, tissues were investigated for expression of ICAM-1, VCAM-1, and for severity of inflammation using a semiquantitative inflammatory score. Dexamethasone treatment resolved all measures of intestinal inflammation. RESULTS: Blocking either ICAM-1, VCAM-1, or alpha(4) integrins had no significant beneficial effect. However, blocking ICAM-1 and alpha(4), or blocking ICAM-1 and VCAM-1, showed a 70% resolution of the active inflammation, but not chronic inflammation. CONCLUSIONS: These findings suggest that blocking ICAM-1 and VCAM-1 may have therapeutic benefit for the acute inflammatory component of Crohn's disease.

Adoptive Transfer↗
PubMed2001

Th1-type responses mediate spontaneous ileitis in a novel murine model of Crohn's disease.

We describe here the immunologic characterization of a new mouse strain, SAMP1/Yit, which spontaneously develops a chronic intestinal inflammation localized to the terminal ileum. The resulting ileitis bears a remarkable resemblance to human Crohn's disease. This strain of mice develops discontinuous, transmural inflammatory lesions in the terminal ileum with 100% penetrance by 30 weeks of age. The intestinal inflammation is characterized by massive infiltration of activated CD4+ and CD8alpha(+)TCRalphabeta(+) T cells into the lamina propria and is accompanied by a dramatic decrease in the intraepithelial lymphocyte CD8alpha(+)TCRgammadelta(+)/CD8alpha(+)TCRalphabeta(+) ratio. The results of adoptive transfer experiments strongly suggest that CD4+ T cells that produce a Th1-like profile of cytokines, e.g., IFN-gamma and TNF, mediate the intestinal inflammation found in SAMP1/Yit mice. In addition, pretreatment of adoptive transfer recipients with a neutralizing anti-TNF antibody prevents the development of intestinal inflammation, suggesting that TNF plays an important role in the pathogenesis of intestinal inflammation in this model. To our knowledge, these data provide the first direct evidence that Th1-producing T cells mediate intestinal inflammation in a spontaneous animal model of human Crohn's disease.

Adoptive Transfer↗
PubMed1999

IL-18, a novel immunoregulatory cytokine, is up-regulated in Crohn's disease: expression and localization in intestinal mucosal cells.

IL-18, a novel immunoregulatory cytokine with potent IFN-gamma-inducing activities, may play an important role in Th1-mediated chronic inflammatory disorders. The aim of the present study was to characterize the expression and localization of IL-18 in colonic specimens and isolated mucosal cell populations from patients with Crohn's disease (CD), a prototypic Th1-mediated disorder. Using a semiquantitative RT-PCR protocol, IL-18 mRNA transcripts were found to be increased in freshly isolated intestinal epithelial cells (IEC) and lamina propria mononuclear cells (LPMC) from CD compared with ulcerative colitis (UC) and noninflamed control (cont) patients, and were more abundant in IEC compared with LPMC. Immunohistochemical analysis of surgically resected colonic tissues localized IL-18 to both LPMC (specifically, macrophages and dendritic cells) as well as IEC. Staining was more intense in CD compared with UC and cont, and in involved (inv) vs noninvolved (n inv) areas. Western blot analysis revealed that an 18. 3-kDa band, consistent with both recombinant and mature human IL-18 protein, was found predominantly in CD vs UC intestinal mucosal biopsies; a second band of 24 kDa, consistent with the inactive IL-18 precursor, was detected in n inv areas from both CD and UC biopsies and was the sole form found in noninflamed cont. To our knowledge, this report is the first describing increased expression of IL-18 in a human Th1-mediated chronic inflammatory disease. In addition, our studies further support the concept that IEC and dendritic cells may possess important immunoregulatory functions in both normal, as well as pathological, mucosal immunity.

Adjuvants, Immunologic↗
PubMed1999

Allelotype of gastric adenocarcinoma.

Gastric adenocarcinoma is a leading cause of cancer mortality world-wide. Yet, the underlying molecular events important in the development of this cancer are largely undefined. Thus, we performed a comprehensive survey for allelic loss on our panel of xenografted human gastric carcinomas. Contaminating normal stromal cells of primary cancers often limit mutational analyses. Xenografted samples of our gastric carcinomas provided optimally enriched tumors for neoplasia that clearly and sensitively demonstrated genetic alterations. Additionally, total absence of allelic signals in these xenografted samples confirmed true loss of alleles rather than just allelic imbalance. Analysis of at least two highly polymorphic microsatellite markers per nonacrocentric chromosomal arm in our xenografted human gastric carcinomas demonstrated significant loss of heterozygosity well above background levels at 3p, 4p, 5q, 8p, 9p, 13q, 17p, and 18q. Several of these loci represent novel findings of significant loss in gastric cancers. On chromosome 17p, p53 is known to be inactivated either by mutation or deletion in a majority of gastric carcinomas. The critical target(s) of inactivation in gastric cancers at these other loci remain to be characterized.

Adenocarcinoma↗
PubMed1999

Mutations of c-kit JM domain are found in a minority of human gastrointestinal stromal tumors.

The c-kit gene encodes a transmembrane receptor kinase (KIT) which is expressed in the majority of human gastrointestinal stromal tumors (GISTs), a subtype of gastrointestinal mesenchymal neoplasms. A previous study identified mutations in the juxtamembrane (JM) domain of c-kit in five of six GISTs (Science 279: 577, 1998). To better define the frequency and spectrum of c-kit gene mutations in mesenchymal neoplasms of the GI tract that had been characterized for KIT protein expression, we examined archived tissue samples for mutations in the JM domain by PCR amplification and DNA sequencing. c-kit JM domain mutations were found in nine of 56 mesenchymal tumors (46 GISTs, eight leiomyomas, two leiomyosarcomas) and occurred exclusively in GISTs (21%). Seven of the nine mutations consisted of intragenic deletions of one to 19 codons. There was one insertion mutation that added 12 codons and one missense mutation (Val560Asp). None of the mutations disrupted the downstream reading frame of the gene. The single missense mutation (Val560Asp) is very similar to the only other missense mutation reported in GISTs (Val599Asp). Of the 46 GISTs, 43 were strongly positive for KIT protein expression and negative for diffuse expression of desmin. Neither KIT expression nor gene mutations were found in gastrointestinal leiomyomas or leiomyosarcomas. We conclude that mutation of the c-kit JM domain does not occur in gastrointestinal mesenchymal neoplasms with well developed-smooth muscle differentiation, and is restricted to GISTs. However, since these mutations are only found in a minority of GISTs, further investigation into the mechanisms of c-kit gene activation in this group of neoplasms is warranted.

Amino Acid Sequence↗
PubMed1999

Origin of microsatellite instability in gastric cancer.

Microsatellite instability (MSI) is observed in 13-44% of gastric carcinoma. The etiology of MSI in gastric carcinoma has not been clearly defined. To assess the role of mismatch repair in the development of MSI in gastric cancer, expression of hMSH2 and hMLH1 was explored. We examined 117 gastric carcinomas for MSI and observed instability at one or more loci in 19 (16%) of these tumors. Of the 19 tumors with MSI, nine exhibited low-rate MSI (MSI-L) with instability at <17% of loci, whereas the remaining 10 exhibited high-rate MSI (MSI-H) with instability at >33% of loci examined. Immunohistochemical staining for hMLH1 and hMSH2 was performed on eight of the tumors with MSI-H, five with MSI-L, and 15 tumors without MSI. All eight tumors with MSI-H showed loss of staining for either hMLH1 (n = 5) or hMSH2 (n = 3). In contrast, tumors with MSI-L or without MSI all showed normal hMSH2 and hMLH1 protein expression patterns. Moreover, all eight of the tumors with MSI-H also showed instability at BAT-26, whereas none of the MSI-L tumors or tumors without instability showed instability at BAT-26. These findings suggest that the majority of high-level MSI in gastric cancer is associated with defects of the mismatch repair pathway. Although larger studies are needed, BAT-26 appears to be a sensitive and specific marker for the MSI-H phenotype in gastric carcinoma.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Mapping of genetic deletions on the long arm of chromosome 4 in human esophageal adenocarcinomas.

Loss of the long arm of chromosome 4 has been identified previously as a common occurrence in adenocarcinomas of the esophagus and gastroesophageal junction by relatively low resolution genetic surveys. To better define the extent of 4q deletion in these neoplasms we isolated DNA from 29 primary carcinomas using microdissection, and used DNA obtained from xenografts of 14 carcinomas grown in immunodeficient mice in an assay of loss of heterozygosity of 25 polymorphic microsatellite markers distributed along the chromosomal arm. Two carcinomas exhibited widespread microsatellite instability and were excluded from deletion mapping. In the remaining 41 carcinomas, loss of heterozygosity was detected in 33 (80%). Twenty-three cancers showed complete or extensive reduction to homozygosity along the length of the long arm. Ten cancers had smaller discrete areas of loss and were principally useful in discerning three non-overlapping areas of consensus genetic deletion. Area 1 centered on marker D4S1534 at 4q21.1-22, area 2 centered on marker D4S620 at 4q32-33, and area 3 centered on marker D4S426 at 4q35. No known tumor suppressor genes map to these loci, but the frequent deletion of these areas in gastroesophageal carcinomas and in other carcinomas suggests that undiscovered tumor suppressor genes may reside here.

Adenocarcinoma↗
PubMed1999

Activating c-kit gene mutations in human germ cell tumors.

The c-kit gene encodes a tyrosine kinase receptor (KIT) that is required in normal spermatogenesis and is expressed in seminomas and dysgerminomas, a subset of human germ cell tumors (GCTs). To determine whether activating mutations of the c-kit gene occur in GCTs, primary tissue samples of 33 testicular and ovarian tumors were examined for mutations in the juxtamembrane and phosphotransferase domains by polymerase chain reaction amplification and DNA sequencing. A novel missense mutation (D816H) was found in the phosphotransferase domain in tumors of seminoma/dysgerminoma differentiation. The c-kit alleles in nonneoplastic tissues from these patients were wild type, suggesting that the mutant alleles were acquired and selected for during malignant transformation. In cell transfection experiments, the D816H mutant protein was a constitutively activated kinase and was constitutively phosphorylated on tyrosine residues. This is the first description of an activating c-kit mutation in GCTs and is evidence that the KIT signal transduction pathway is important in the pathogenesis of neoplasms with seminoma differentiation.

Amino Acid Substitution↗
PubMed1999

Analysis of chromosome 9p21 deletion and p16 gene mutation in salivary gland carcinomas.

The chromosomal locus 9p21 contains the p16(INK4a/CDKN2/MTS1) tumor suppressor gene that has been implicated in a variety of tumor types, including carcinomas of the head and neck, esophagus, and pancreas. To determine whether the loss of this gene is involved in salivary gland cancers, 35 carcinomas and paired nonneoplastic specimens were analyzed for loss of heterozygosity (LOH) of polymorphic genetic markers located in the region of interest. Five types of salivary gland tumors were studied: mucoepidermoid carcinoma, salivary duct carcinoma, adenoid cystic carcinoma, acinic cell carcinoma, and polymorphous low-grade adenocarcinoma. Seven of 9 salivary duct carcinomas showed LOH of 1 or more polymorphic markers. In 1 case of salivary duct carcinoma with LOH, we confirmed a deletion of bp 240-254 within exon 2. In addition, another salivary duct carcinoma showed a homozygous deletion of p16 in differential polymerase chain reaction analysis. Loss of heterozygosity was found in 1 of 10 adenoid cystic carcinomas and 1 of 8 mucoepidermoid carcinomas and was absent in the remaining subtypes. No mutations in exon 1 or exon 2 or homozygous deletion of p16 were found in these 2 particular neoplasms with LOH. These results suggest that inactivation of p16 is important in the development or progression of at least some salivary duct carcinomas, but we found no evidence that its alteration plays a role in the other subtypes examined.

Adenocarcinoma↗