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Biomedical subjects

M Lerman

Publications and source records attributed to M Lerman.

At least 19 recordsLinked to original sources
PubMed2000

Integrin-mediated RON growth factor receptor phosphorylation requires tyrosine kinase activity of both the receptor and c-Src.

Cooperation between integrins and growth factor receptors plays an important role in the regulation of cell growth, differentiation, and survival. The function of growth factor receptor tyrosine kinases (RTKs) can be regulated by cell adhesion to extracellular matrix (ECM) even in the absence of ligand. We investigated the pathway involved in integrin-mediated RTK activation, using RON, the receptor for macrophage-stimulating protein. Adhesion of RON-expressing epithelial cells to ECM caused phosphorylation of RON, which depended on the kinase activity of both RON itself and c-Src. This conclusion is based on these observations: 1) ECM-induced RON phosphorylation was inhibited in cells expressing kinase-inactive c-Src; 2) active c-Src could phosphorylate immunoprecipitated RON from ECM-stimulated cells but not from unstimulated cells; and 3) ECM did not cause RON phosphorylation in cells expressing kinase-dead RON, nor could active c-Src phosphorylate RON immunoprecipitated from these cells. The data fit a pathway in which ECM-induced integrin aggregation causes both c-Src activation and RON oligomerization followed by RON kinase-dependent autophosphorylation; this results in RON becoming a target for activated c-Src, which phosphorylates additional tyrosines on RON. Integrin-induced epidermal growth factor receptor (EGFR) phosphorylation also depended on both EGFR and c-Src kinase activities. This sequence appears to be a general pathway for integrin-dependent growth factor RTK activation.

Animals↗
PubMed2000

Functional properties of a new voltage-dependent calcium channel alpha(2)delta auxiliary subunit gene (CACNA2D2).

We have positionally cloned and characterized a new calcium channel auxiliary subunit, alpha(2)delta-2 (CACNA2D2), which shares 56% amino acid identity with the known alpha(2)delta-1 subunit. The gene maps to the critical human tumor suppressor gene region in chromosome 3p21.3, showing very frequent allele loss and occasional homozygous deletions in lung, breast, and other cancers. The tissue distribution of alpha(2)delta-2 expression is different from alpha(2)delta-1, and alpha(2)delta-2 mRNA is most abundantly expressed in lung and testis and well expressed in brain, heart, and pancreas. In contrast, alpha(2)delta-1 is expressed predominantly in brain, heart, and skeletal muscle. When co-expressed (via cRNA injections) with alpha(1B) and beta(3) subunits in Xenopus oocytes, alpha(2)delta-2 increased peak size of the N-type Ca(2+) currents 9-fold, and when co-expressed with alpha(1C) or alpha(1G) subunits in Xenopus oocytes increased peak size of L-type channels 2-fold and T-type channels 1.8-fold, respectively. Anti-peptide antibodies detect the expression of a 129-kDa alpha(2)delta-2 polypeptide in some but not all lung tumor cells. We conclude that the alpha(2)delta-2 gene encodes a functional auxiliary subunit of voltage-gated Ca(2+) channels. Because of its chromosomal location and expression patterns, CACNA2D2 needs to be explored as a potential tumor suppressor gene linking Ca(2+) signaling and lung, breast, and other cancer pathogenesis. The homologous location on mouse chromosome 9 is also the site of the mouse neurologic mutant ducky (du), and thus, CACNA2D2 is also a candidate gene for this inherited idiopathic generalized epilepsy syndrome.

Amino Acid Sequence↗
PubMed2000

Mesenchymal-epithelial transition in the developing metanephric kidney: gene expression study by differential display.

The developing metanephric kidney is a convenient model to study molecular events associated with epithelial cell differentiation. To determine the genes involved in the defining event of this process, namely, the conversion of metanephric mesenchyme to the epithelium of the nephron, we applied differential display (DD) techniques. Explants of rat metanephric mesenchymes were induced to condense ex vivo with fibroblast growth factor 2 (FGF2) or to form tubules with FGF2 and conditioned medium (CM) from a cell line (RUB1) of ureteric bud, the renal inductive tissue. Three time points (6, 24, and 72 h) were chosen to track the dynamics of gene expression during morphogenesis. Seventy-two up- or down-regulated mRNAs were identified, including 36 novel sequences and those of cell cycle regulatory proteins (TGF-beta2, Cyclin D1, p57Kip2), transcription factors (beta-catenin, Sox11, DP1), signaling proteins (SH3-domain binding protein, G-protein-coupled receptor, Ser-Thr protein kinase), cell adhesion molecules (syndecan-4, integrin-beta1), and also gene33, H19, SM20, IGFBP5, MAMA receptor, lectin, keratin, beta-tubulin, calreticulin, GRP78, ERp72, MnSoD, thioredoxin, and others. Some have previously been associated with kidney development and serve as good controls for expected changes, while most have not been linked with kidney epithelial cell differentiation. Using thin sections of embryonic kidney and labeled antisense RNA probes, we applied RNA hybridization to confirm the results of DD and related the expression of these genes to specific cell lineages of the developing kidney. These results provide a window into the events that mediate this critical differentiation process and suggest that a limited number of interrelated events direct the epithelial conversion of metanephric mesenchyme. genesis 27:22-31, 2000. Published 2000 Wiley-Liss, Inc.

Animals↗
PubMed2000

p12(DOC-1), a growth suppressor, associates with DNA polymerase alpha/primase.

p12(DOC-1) is a growth suppressor identified and isolated from normal keratinocytes. Ectopic expression of p12(DOC-1) in squamous carcinoma cells led to the reversion of in vitro transformation phenotypes including anchorage independence, doubling time, and morphology. Here we report that p12(DOC-1) associates with DNA polymerase alpha/primase (pol-alpha:primase) in vitro and in cells. The pol-alpha:primase binding domain in p12(DOC-1) is mapped to the amino-terminal six amino acid (MSYKPN). The biological effect of p12(DOC-1) on pol-alpha:primase was examined using in vitro DNA replication assays. Using the SV40 DNA replication assay, p12(DOC-1) suppresses DNA replication, leveling at approximately 50%. Similar results were obtained using the M13 single-stranded DNA synthesis assay. Analysis of the DNA replication products revealed that p12(DOC-1) affects the initiation step, not the elongation phase. The p12(DOC-1) suppression of DNA replication is likely to be mediated either by a direct inhibitory effect on pol-alpha:primase or by its effect on cyclin-dependent kinase 2 (CDK2), a recently identified p12(DOC-1)-associated protein known to stimulate DNA replication by phosphorylating pol-alpha:primase. p12(DOC-1) suppresses CDK2-mediated phosphorylation of pol-alpha:primase. These data support a role of p12(DOC-1) as a regulator of DNA replication by direct inhibition of pol-alpha:primase or by negatively regulating the CDK2-mediated phosphorylation of pol-alpha:primase.

Amino Acid Sequence↗
PubMed2000

p12(DOC-1) is a novel cyclin-dependent kinase 2-associated protein.

Regulated cyclin-dependent kinase (CDK) levels and activities are critical for the proper progression of the cell division cycle. p12(DOC-1) is a growth suppressor isolated from normal keratinocytes. We report that p12(DOC-1) associates with CDK2. More specifically, p12(DOC-1) associates with the monomeric nonphosphorylated form of CDK2 (p33CDK2). Ectopic expression of p12(DOC-1) resulted in decreased cellular CDK2 and reduced CDK2-associated kinase activities and was accompanied by a shift in the cell cycle positions of p12(DOC-1) transfectants ( upward arrow G(1) and downward arrow S). The p12(DOC-1)-mediated decrease of CDK2 was prevented if the p12(DOC-1) transfectants were grown in the presence of the proteosome inhibitor clasto-lactacystin beta-lactone, suggesting that p12(DOC-1) may target CDK2 for proteolysis. A CDK2 binding mutant was created and was found to revert p12(DOC-1)-mediated, CDK2-associated cell cycle phenotypes. These data support p12(DOC-1) as a specific CDK2-associated protein that negatively regulates CDK2 activities by sequestering the monomeric pool of CDK2 and/or targets CDK2 for proteolysis, reducing the active pool of CDK2.

Blotting, Western↗
PubMed1999

Analysis of NotI linking clones isolated from human chromosome 3 specific libraries.

We have partially sequenced more than 1000 NotI linking clones isolated from human chromosome 3-specific libraries. Of these clones, 152 were unique chromosome 3-specific clones. The clones were precisely mapped using a combination of fluorescence in situ hybridization (FISH) and hybridization to somatic cell or radiation hybrids. Two- and three-color FISH was used to order the clones that mapped to the same chromosomal region, and in some cases, chromosome jumping was used to resolve ambiguous mapping. When this NotI restriction map was compared with the yeast artificial chromosome (YAC) based chromosome 3 map, significant differences in several chromosome 3 regions were observed. A search of the EMBL nucleotide database with these sequences revealed homologies (90-100%) to more than 100 different genes or expressed sequence tags (ESTs). Many of these homologies were used to map new genes to chromosome 3. These results suggest that sequencing NotI linking clones, and sequencing CpG islands in general, may complement the EST project and aid in the discovery of all human genes by sequencing random cDNAs. This method may also yield information that cannot be obtained by the EST project alone; namely, the identification of the 5' ends of genes, including potential promoter/enhancer regions and other regulatory sequences

Animals↗
PubMed1999

Protective function of von Hippel-Lindau protein against impaired protein processing in renal carcinoma cells.

The absence of functional von Hippel-Lindau (VHL) tumor suppressor gene leads to the development of neoplasias characteristic of VHL disease, including renal cell carcinoma (RCC). Here, we compared the sensitivity of RCC cells lacking VHL gene function with that of RCC cells expressing the wild-type VHL gene (wtVHL) after exposure to various stresses. While the response to most treatments was not affected by the VHL gene status, glucose deprivation was found to be much more cytotoxic for RCC cells lacking VHL gene function than for wtVHL-expressing cells. The heightened sensitivity of VHL-deficient cells was not attributed to dissimilar energy requirements or to differences in glucose uptake, but more likely reflects a lesser ability of VHL-deficient cells to handle abnormally processed proteins arising from impaired glycosylation. In support of this hypothesis, other treatments which act through different mechanisms to interfere with protein processing (i.e., tunicamycin, brefeldin A, and azetidine) were also found to be much more toxic for VHL-deficient cells. Furthermore, ubiquitination of cellular proteins was elevated in VHL-deficient cells, particularly after glucose deprivation, supporting a role for the VHL gene in ubiquitin-mediated proteolysis. Accordingly, the rate of elimination of abnormal proteins was lower in cells lacking a functional VHL gene than in wtVHL-expressing cells. Thus, pVHL appears to participate in the elimination of misprocessed proteins, such as those arising in the cell due to the unavailability of glucose or to other stresses.

Apoptosis↗
PubMed1998

Homozygous deletions at 3p12 in breast and lung cancer.

We have constructed a physical map of the region homozygously deleted in the U2020 cell line at 3p12, including the location of putative CpG islands. Adjacent to one of these islands, we have identified and cloned a new gene (DUTT1) and used probes from this gene to detect two other homozygous deletions occurring in lung and breast carcinomas: the smallest deletion is within the gene itself and would result in a truncated protein. The DUTT1 gene is a member of the neural cell adhesion molecule family, although its widespread expression suggests it plays a less specialized role compared to other members of the family.

Breast Neoplasms↗
PubMed1998

Computerized polymorphic marker identification: experimental validation and a predicted human polymorphism catalog.

A computational system for the prediction of polymorphic loci directly and efficiently from human genomic sequence was developed and verified. A suite of programs, collectively called POMPOUS (polymorphic marker prediction of ubiquitous simple sequences) detects tandem repeats ranging from dinucleotides up to 250 mers, scores them according to predicted level of polymorphism, and designs appropriate flanking primers for PCR amplification. This approach was validated on an approximately 750-kilobase region of human chromosome 3p21.3, involved in lung and breast carcinoma homozygous deletions. Target DNA from 36 paired B lymphoblastoid and lung cancer lines was amplified and allelotyped for 33 loci predicted by POMPOUS to be variable in repeat size. We found that among those 36 predominately Caucasian individuals 22 of the 33 (67%) predicted loci were polymorphic with an average heterozygosity of 0.42. Allele loss in this region was found in 27/36 (75%) of the tumor lines using these markers. POMPOUS provides the genetic researcher with an additional tool for the rapid and efficient identification of polymorphic markers, and through a World Wide Web site, investigators can use POMPOUS to identify polymorphic markers for their research. A catalog of 13,261 potential polymorphic markers and associated primer sets has been created from the analysis of 141,779,504 base pairs of human genomic sequence in GenBank. This data is available on our Web site (pompous.swmed.edu) and will be updated periodically as GenBank is expanded and algorithm accuracy is improved.

Computer Communication Networks↗
PubMed1998

The DUTT1 gene, a novel NCAM family member is expressed in developing murine neural tissues and has an unusually broad pattern of expression.

A new member of the NCAM family mapping to 3p12 has been isolated and predicted to be arranged in five immunoglobulin-like domains and three fibronectin-like domains which are particularly homologous to L1. There is a transmembrane domain and a long cytoplasmic region with no detectable homology to other sequences. Although less closely related to DCC, another family member, both share a loop of positively charged amino acids within the first immunoglobulin domain, unique to these two members of this very large gene family. Preliminary studies of expression in mouse embryos support an inferred role in neural development, but the observation of widespread gene expression in adult human tissues indicates that this protein has additional functions to those performed in neural cells.

Amino Acid Sequence↗
PubMed1998

Inherited carcinomas of the kidney.

Studies of families with inherited carcinomas have provided powerful tools to identify the genes involved in the pathogenesis of human cancers. In this review, we summarize the clinical, pathological, and genetic characteristics of the inherited carcinomas of the kidney. We emphasize the observation that different genes predispose to histologically different types of renal carcinoma. Hereditary papillary renal carcinoma, a recently described inherited disorder, is discussed in detail along with the predisposing gene, the MET protooncogene. The data support a classification of renal carcinomas based on molecular genetics.

Adenocarcinoma, Clear Cell↗
PubMed1998

Medical, cognitive, emotional, and behavioral outcomes in school-age children conceived by in-vitro fertilization.

Assessed long-term effects of assisted reproduction technologies of in-vitro fertilization (IVF) and related techniques of embryo transfer (ET) on children's adjustment. 51 school-age Israeli children conceived by IVF/ET were compared with 51 control-matched children conceived spontaneously. The assessment included a comprehensive medical evaluation, a psychological examination, teachers' reports, parents' reports, and children's self-reports. As compared with controls, IVF/ET children did not reveal significant differences in physical and neurological status or on cognitive measures of IQ, visual-motor coordination, visual memory, and verbal comprehension. Nevertheless, the IVF/ET children were scored lower by teachers on measures of socioemotional adjustment in school and on self-report measures of anxiety, aggression, and depression. Among IVF/ET children, the tendency to be at a greater risk for emotional disturbances was exacerbated among boys and among children whose parents were older.

Affective Symptoms↗
PubMed1996

Germline mutations in the Von Hippel-Lindau disease (VHL) gene in families from North America, Europe, and Japan.

Germline mutation analysis was performed in 469 VHL families from North America, Europe, and Japan. Germline mutations were identified in 300/469 (63%) of the families tested; 137 distinct intragenic germline mutations were detected. Most of the germline VHL mutations (124/137) occurred in 1-2 families; a few occured in four or more families. The common germline VHL mutations were: delPhe76, Asn78Ser, Arg161Stop, Arg167Gln, Arg167Trp, and Leu178Pro. In this large series, it was possible to compare the effects of identical germline mutations in different populations. Germline VHL mutations produced similar cancer phenotypes in Caucasian and Japanese VHL families. Germline VHL mutations were identified that produced three distinct cancer phenotypes: (1) renal carcinoma without pheochromocytoma, (2) renal carcinoma with pheochromocytoma, and (3) pheochromocytoma alone. The catalog of VHL germline mutations with phenotype information should be useful for diagnostic and prognostic studies of VHL and for studies of genotype-phenotype correlations in VHL.

Adrenal Gland Neoplasms↗
PubMed1994

Development of children born after ovarian superovulation induced by long-acting gonadotropin-releasing hormone agonist and menotropins, and by in vitro fertilization.

The use of a gonodotropin-releasing hormone (Gn-RH) agonist in an in vitro fertilization (IVF) program raises the question of any influence on the physical, neurologic, and mental development of the children. We compared the development of children born after long-acting Gn-RH agonist treatment with that of children born after spontaneous pregnancies. Children from singleton pregnancies and > or = 28 months of age were examined by a pediatric neurologist and a psychologist who did not know to which group the children belonged. The General Cognitive Index test was used. Each group included 30 children. Five children cooperated only partly. Physical and neurologic findings were normal in all children, except that one in the group born after in vitro fertilization had diffuse hypotonia, attention-deficit hyperactivity disorder, and hyperactivity. The General Cognitive Index for the 26 children in the study group and the 29 children in the control group who fully cooperated were 102 +/- 13.3 and 106 +/- 13.5, respectively (p = 0.37). The verbal perception, motor, and memory indexes were not significantly different. We conclude that the long-acting Gn-RH agonist had no clinically identifiable influence on the development of these children.

Adult↗
PubMed1994

Hereditary papillary renal cell carcinoma.

We describe a 3 generation family with members affected with papillary renal cell carcinoma, an uncommon histological type of renal cell carcinoma. Multiple tumors of varying size were present in both kidneys of affected family members. The disorder was not linked to polymorphic markers on chromosome 3p and there was no loss of heterozygosity at loci on 3p in renal tumors. The results suggest the presence of a renal cell carcinoma gene not located on 3p that predisposes to renal cell carcinoma with a distinct histological appearance. The inherited disorder in this family appears to be different from recognized hereditary cancer syndromes.

Adolescent↗
PubMed1994

Biological and environmental correlates of developmental outcome of prematurely born infants in early adolescence.

Examined the role of biological factors (birth weight and perinatal medical complications) and psychosocial factors (maternal attitudes, paternal involvement, mother's personal state, marital adjustment, family relations, and socioeconomic status) in predicting long-term outcome of 90 Israeli adolescents born prematurely at very low birth weight (VLBW). As compared with 90 adolescents born full-term at normal birth weight (NBW), the VLBW children scored lower on all measures except reading comprehension. IQ, visual-motor coordination, and hyperactive behavior were predicted by both biological and psychosocial variables, visual memory by biological variables, and reading comprehension by psychosocial variables. The findings support chiefly the main effects model of developmental psychopathology (i.e., biological and psychosocial variables are additive in predicting outcomes), but also the interactional model (e.g., SES was influential in predicting visual-motor coordination and hyperactive behavior in the VLBW group but not in the NBW group).

Adolescent↗
PubMed1994

Administration of half-dose theophylline together with ketotifen to asthmatic children--a double-blind, placebo-controlled study.

Administration of theophylline to asthmatic children is frequently associated with an adverse influence on their behavior. The efficacy and behavioral effects of the administration of high-dose theophylline (T) and ketotifen (K) in various combinations were evaluated prospectively in a double-blind, placebo controlled study in 55 children with moderately severe perennial asthma. During a baseline period of 2 weeks, theophylline (serum level of 10-20 micrograms/ml) was administered to all the children. After this period the patients were randomly allocated into four comparable groups. The children were treated during a 12-week period with: T+K-Placebo (T group); T+K (T+K group); half-dose T+K (T/2 + K group); or placebo of both T and K (P group). During the 12-week treatment period, as compared to the baseline period, only the three groups of children who received active therapy (T+P, T+K, T/2 + K) showed a similar reduction in the number of days with asthmatic symptomatology, improvement of the total asthmatic symptoms score, and increased PEFR. The behavioral activity of the children (assessed by the Conner's rating scale) improved significantly only in the groups receiving placebo or T/2 + K. The results of this study suggest that a combination therapy of half the recommended therapeutic dose of theophylline with ketotifen can be clinically as effective as therapy with a full dose of theophylline, but with significantly less adverse behavioral effects.

Asthma↗