Biomedical subjects

Daniel Birnbaum

Publications and source records attributed to Daniel Birnbaum.

At least 19 recordsLinked to original sources

PubMed2006

FGFR1 and WT1 are markers of human prostate cancer progression.

BACKGROUND: Androgen-independent prostate adenocarcinomas are responsible for about 6% of overall cancer deaths in men. METHODS: We used DNA microarrays to identify genes related to the transition between androgen-dependent and androgen-independent stages in the LuCaP 23.1 xenograft model of prostate adenocarcinoma. The expression of the proteins encoded by these genes was then assessed by immunohistochemistry on tissue microarrays (TMA) including human prostate carcinoma samples issued from 85 patients who had undergone radical prostatectomy. RESULTS: FGFR1, TACC1 and WT1 gene expression levels were associated with the androgen-independent stage in xenografts and human prostate carcinoma samples. MART1 protein expression was correlated with pT2 tumor stages. CONCLUSION: Our results suggest that each of these four genes may play a role, or at least reflect a stage of prostate carcinoma growth/development/progression.

Adenocarcinoma↗

PubMed2006

Frequency, prognostic impact, and subtype association of 8p12, 8q24, 11q13, 12p13, 17q12, and 20q13 amplifications in breast cancers.

BACKGROUND: Oncogene amplification and overexpression occur in tumor cells. Amplification status may provide diagnostic and prognostic information and may lead to new treatment strategies. Chromosomal regions 8p12, 8q24, 11q13, 17q12 and 20q13 are recurrently amplified in breast cancers. METHODS: To assess the frequencies and clinical impact of amplifications, we analyzed 547 invasive breast tumors organized in a tissue microarray (TMA) by fluorescence in situ hybridization (FISH) and calculated correlations with histoclinical features and prognosis. BAC probes were designed for: (i) two 8p12 subregions centered on RAB11FIP1 and FGFR1 loci, respectively; (ii) 11q13 region centered on CCND1; (iii) 12p13 region spanning NOL1; and (iv) three 20q13 subregions centered on MYBL2, ZNF217 and AURKA, respectively. Regions 8q24 and 17q12 were analyzed with MYC and ERBB2 commercial probes, respectively. RESULTS: We observed amplification of 8p12 (amplified at RAB11FIP1 and/or FGFR1) in 22.8%, 8q24 in 6.1%, 11q13 in 19.6%, 12p13 in 4.1%, 17q12 in 9.9%, 20q13Z (amplified at ZNF217 only) in 9.9%, and 20q13Co (co-amplification of two or three 20q13 loci) in 8.5% of cases. The 8q24, 12p13, and 17q12 amplifications were correlated with high grade. The most frequent single amplifications were 8p12 (9.8%), 8q24 (3.3%) and 12p13 (3.3%), 20q13Z and 20q13Co (1.6%) regions. The 17q12 and 11q13 regions were never found amplified alone. The most frequent co-amplification was 8p12/11q13. Amplifications of 8p12 and 17q12 were associated with poor outcome. Amplification of 12p13 was associated with basal molecular subtype. CONCLUSION: Our results establish the frequencies, prognostic impacts and subtype associations of various amplifications and co-amplifications in breast cancers.

Adult↗

PubMed2006

Prognosis and gene expression profiling of 20q13-amplified breast cancers.

PURPOSE: Amplification of chromosomal region 20q13 occurs in breast cancer but remains poorly characterized. EXPERIMENTAL DESIGN: To establish the frequency of 20q13 amplification and select the amplified cases to be studied, we used fluorescence in situ hybridization of bacterial artificial chromosome probes for three 20q13 loci (MYBL2, STK6, ZNF217) on sections of tissue microarrays containing 466 primary carcinoma samples. We used Affymetryx whole-genome DNA microarrays to establish the gene expression profiles of 20q13-amplified tumors and quantitative reverse transcription-PCR to validate the results. RESULTS: We found 36 (8%) 20q13-amplified samples. They were distributed in two types: type 1 tumors showed ZNF217 amplification only, whereas type 2 tumors showed amplification at two or three loci. Examination of the histoclinical features of the amplified tumors showed two strikingly opposite data. First, type 1 tumors were more frequently lymph node-negative tumors but were paradoxically associated with a poor prognosis. Second, type 2 tumors were more frequently lymph node-positive tumors but were paradoxically associated with a good prognosis. Type 1 and type 2 showed different gene expression profiles. No 20q13 gene could be associated with type 1 amplification, whereas several 20q13 genes were overexpressed in type 2 tumors. CONCLUSIONS: Our results suggest that amplified tumors of types 1 and 2 are two distinct entities resulting from two different mechanisms and associated to different prognosis.

Breast Neoplasms↗

PubMed2006

Proteomics of breast cancer: principles and potential clinical applications.

Progresses in screening, early diagnosis, prediction of aggressiveness and of therapeutic response or toxicity, and identification of new targets for therapeutic will improve survival of breast cancer. These progresses will likely be accelerated by the new proteomic techniques. In this review, we describe the different techniques currently applied to clinical samples of breast cancer and the most important results obtained with the two most popular proteomic approaches in translational research (tissue microarrays and SELDI-TOF).

Breast Neoplasms↗

PubMed2006

Direct and heterologous approaches to identify the LET-756/FGF interactome.

BACKGROUND: Fibroblast growth factors (FGFs) are multifunctional proteins that play important roles in cell communication, proliferation and differentiation. However, many aspects of their activities are not well defined. LET-756, one of the two C. elegans FGFs, is expressed throughout development and is essential for worm development. It is both expressed in the nucleus and secreted. RESULTS: To identify nuclear factors associated with LET-756, we used three approaches. First, we screened a two-hybrid cDNA library derived from mixed stages worms and from a normalized library, using LET-756 as bait. This direct approach allowed the identification of several binding partners that play various roles in the nucleus/nucleolus, such as PAL-1, a transcription regulator, or RPS-16, a component of the small ribosomal subunit. The interactions were validated by co-immunoprecipitation and determination of their site of occurrence in mammalian cells. Second, because patterns of protein interactions may be conserved throughout species, we searched for orthologs of known mammalian interactors and measured binary interaction with these predicted candidates. We found KIN-3 and KIN-10, the orthologs of CK2alpha and CK2beta, as new partners of LET-756. Third, following the assumption that recognition motifs mediating protein interaction may be conserved between species, we screened a two-hybrid cDNA human library using LET-756 as bait. Among the few FGF partners detected was 14-3-3beta. In support of this interaction we showed that the two 14-3-3beta orthologous proteins, FTT-1 and FTT-2/PAR-5, interacted with LET-756. CONCLUSION: We have conducted the first extensive search for LET-756 interactors using a multi-directional approach and established the first interaction map of LET-756/FGF with other FGF binding proteins from other species. The interactors identified play various roles in developmental process or basic biochemical events such as ribosome biogenesis.

14-3-3 Proteins↗

PubMed2006

Gene expression profiling shows medullary breast cancer is a subgroup of basal breast cancers.

Medullary breast cancer (MBC) is a rare but enigmatic pathologic type of breast cancer. Despite features of aggressiveness, MBC is associated with a favorable prognosis. Morphologic diagnosis remains difficult in many cases. Very little is known about the molecular alterations involved in MBC. Notably, it is not clear whether MBC and ductal breast cancer (DBC) represent molecularly distinct entities and what genes/proteins might account for their differences. Using whole-genome oligonucleotide microarrays, we compared gene expression profiles of 22 MBCs and 44 grade III DBCs. We show that MBCs are less heterogeneous than DBCs. Whereas different molecular subtypes (luminal A, luminal B, basal, ERBB2-overexpressing, and normal-like) exist in DBCs, 95% MBCs display a basal profile, similar to that of basal DBCs. Supervised analysis identified gene expression signatures that discriminated MBCs from DBCs. Discriminator genes are associated with various cellular processes related to MBC features, in particular immune reaction and apoptosis. As compared with MBCs, basal DBCs overexpress genes involved in smooth muscle cell differentiation, suggesting that MBCs are a distinct subgroup of basal breast cancer with limited myoepithelial differentiation. Finally, MBCs overexpress a series of genes located on the 12p13 and 6p21 chromosomal regions known to contain pluripotency genes. Our results contribute to a better understanding of MBC and of mammary oncogenesis in general.

Adult↗

PubMed2006

Intracellular trafficking of LET-756, a fibroblast growth factor of C. elegans, is controlled by a balance of export and nuclear signals.

The superfamily of fibroblast growth factors (FGF), which counts 22 members in humans, exerts many functions during animal development and adult life. LET-756 is one of the two FGFs of the nematode C. elegans. Re-introduction of LET-756 in a null mutant strain restores viability, allowing the study of structural requirements for LET-756 trafficking and function. LET-756 protein has several regions and motifs, including a non-classical internal motif required for secretion. We show here that a main difference in the wild-type LET-756 molecule and a truncated molecule that mimics a partial loss-of-function mutant lies on subnuclear expression. Using Cos-1 cells and rescue activity we show that: (i) nuclear localization is due to various redundant NLS, one of them acting as a nucleolar localization signal; (ii) nuclear LET-756 is addressed to the speckles by a stretch of glutamine residues; (iii) nuclear LET-756 is trafficking between speckles and nucleoli; (iv) in the nucleolus, LET-756 is associated with proteins of the rRNA splicing compartment; (v) changing LET-756 secretion signal prevents its nuclear localization. We propose that LET-756 exerts its functions through a balance between secreted and nuclear forms due to two opposite addressing signals, (i) synergy of several NLS and (ii) attenuated secretion signal.

Animals↗

PubMed2006

[Genetic factors and colorectal cancers development: therapeutic impact].

Colorectal tumorigenesis is associated with the progressive increase of epithelium dysplasia and wall invasion. These criteria are evaluated through histological staging, that enables a reliable estimation of patient prognosis, and is the best tool for therapeutic decision. Adjuvant chemotherapy is systematically proposed in case of lymph nodes and/or distant metastases (stages III and IV respectively). Its benefit in stage II tumors however remains unclear. Independently of the nature of the treatment, one third of all stage II-III tumors will metastasize. One important element to improve our tools for therapeutic decision is the identification of prognostic parameters, independent of the histological and morphological classifications. In a preliminary study, we allelotyped a series of 401 colon tumors and have shown that 5q and 8p allelic status were significantly predictive of the patients evolution. As a first approach, analysis of 47 tumors using microarray expression measures has allowed to validate the strong correlation between RNA levels and genomic status (i.e. mutation and allelic status) of known genes (APC, SMAD4, TP53, MLH1). We are now planning to characterize a series of 185 stage II-III colon tumors at both genomic and transcriptomic levels, in combination with the clinicopathological findings. Disease-free patients were followed at least 3 years after surgical resection. A tight collaboration of 5 departments of digestive oncology allowed to collect all clinical and biological resources for this project. Depending on our findings, correlations will be made between gene expression levels and somatic mutations of the coreesponding genes. Real time RT-PCR and immunohistochemical analyses will be performed on selected genes. Finally, biological mechanisms will be investigated to look for new therapeutic targets.

Colorectal Neoplasms↗

PubMed2006

Gene expression profiling and clinical outcome in breast cancer.

Pathologic and clinical heterogeneity of breast cancer reflects the poorly documented, complex, and combinatory molecular basis of the disease and is in part responsible for therapeutic failures. The DNA microarray technique allows the analysis of RNA expression of several thousands of genes simultaneously in a sample. There are multiple potential applications of the technique in cancer research. A number of recent studies have shown the promising role of gene expression profiling in breast cancer by identifying new prognostic subclasses unidentifiable by conventional parameters and new prognostic and/or predictive gene signatures, whose predictive impact is superior to conventional histoclinical prognostic factors. In this review we describe current use of DNA microarrays in the prognosis of breast cancer. We also discuss issues that need to be addressed in the near future to allow the method to reach its full potential.

Breast Neoplasms↗

PubMed2005

Oncogenic tyrosine kinase of malignant hemopathy targets the centrosome.

Myeloproliferative disorders (MPD) are malignant diseases of hematopoietic progenitor cells. Many MPDs result from a chromosomal translocation that creates a fusion gene encoding a chimeric kinase. The fibroblast growth factor receptor 1 (FGFR1)-MPD is characterized by the fusion of the FGFR1 kinase with various partners, including FOP. We show here that both normal FOP and FOP-FGFR1 fusion kinase localize to the centrosome. The fusion kinase encounters substrates at the centrosome where it induces strong phosphorylation on tyrosine residues. Treatment with FGFR1 kinase inhibitor SU5402 abolishes FOP-FGFR1-induced centrosomal phosphorylation and suppresses the proliferative and survival potentials of FOP-FGFR1 Ba/F3 cells. We further show that FOP-FGFR1 allows cells to overcome G1 arrest. Therefore, the FOP-FGFR1 fusion kinase targets the centrosome, activates signaling pathways at this organelle, and sustains continuous entry in the cell cycle. This could represent a potential new mechanism of oncogenic transformation occurring specifically at the centrosome.

Animals↗

PubMed2005

Junctional recruitment of mammalian Scribble relies on E-cadherin engagement.

Members of the LAP protein family, LET-413 in Caenorhabditis elegans, Scribble in Drosophila melanogaster, and Erbin, Lano, Densin-180 and hScrib in mammals, have conserved structural features. LET-413 and Scribble are junctional proteins involved in establishing and maintaining epithelial cell polarity. scribble also behaves as a neoplastic tumor suppressor gene. We show here that, in epithelial cells, hScrib is recruited at cell-cell junctions in an E-cadherin-dependent manner as shown by calcium switch assays in MDCK cells, re-expression of E-cadherin in MDA-231 cells treated by 5-Aza-2'-deoxycytidine (5Aza), and siRNA experiments. hScrib is restricted at the basolateral membrane of epithelial cells by its LRR domain, and is enriched in Triton X-100-insoluble fractions. In breast cancers, most lobular tumors did not express hScrib and E-cadherin while ductal tumors had a less frequent downregulation of hScrib. Our data provide additional insights on the modalities of recruitment of hScrib at the cell-cell junctions, and establish a potential link between the E-cadherin and hScrib tumor suppressors.

Animals↗

PubMed2005

Acute yohimbine increases laboratory-measured impulsivity in normal subjects.

BACKGROUND: State-dependent changes in impulsivity may be related to norepinephrine. To examine possible relationships between norepinephrine and acute changes in impulsivity, we measured effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on laboratory-measured impulsivity in healthy subjects without psychiatric or substance-use disorders. METHODS: Impulsivity was assessed using the Immediate and Delayed Memory Tasks (IMT-DMT), derived from the Continuous Performance Test, before and after placebo or two doses of yohimbine, given 4 days apart. Blood pressure was monitored, and psychiatric symptoms were measured using self-rated visual analog scales. RESULTS: Yohimbine was associated with a dose-related increase in impulsive IMT commission errors, with an increase of > 50% relative to baseline at the higher dose. The activation factor of the Internal State Scale was increased at the same dose. CONCLUSIONS: These results are consistent with increased impulsivity in normal subjects given yohimbine, possibly related to increased norepinephrine.

Adrenergic alpha-Antagonists↗

PubMed2005

Gene expression profiling identifies molecular subtypes of inflammatory breast cancer.

Breast cancer is a heterogeneous disease. Comprehensive gene expression profiles obtained using DNA microarrays have revealed previously indistinguishable subtypes of noninflammatory breast cancer (NIBC) related to different features of mammary epithelial biology and significantly associated with survival. Inflammatory breast cancer (IBC) is a rare, particular, and aggressive form of disease. Here we have investigated whether the five molecular subtypes described for NIBC (luminal A and B, basal, ERBB2 overexpressing, and normal breast-like) were also present in IBC. We monitored the RNA expression of approximately 8,000 genes in 83 breast tissue samples including 37 IBC, 44 NIBC, and 2 normal breast samples. Hierarchical clustering identified the five subtypes of breast cancer in both NIBC and IBC samples. These subtypes were highly similar to those defined in previous studies and associated with similar histoclinical features. The robustness of this classification was confirmed by the use of both alternative gene set and analysis method, and the results were corroborated at the protein level. Furthermore, we show that the differences in gene expression between NIBC and IBC and between IBC with and without pathologic complete response that we have recently reported persist in each subtype. Our results show that the expression signatures defining molecular subtypes of NIBC are also present in IBC. Obtained using different patient series and different microarray platforms, they reinforce confidence in the expression-based molecular taxonomy but also give evidence for its universality in breast cancer, independently of a specific clinical form.

Adenocarcinoma↗

PubMed2005

Protein expression profiling identifies subclasses of breast cancer and predicts prognosis.

Breast cancer is a heterogeneous disease whose evolution is difficult to predict by using classic histoclinical prognostic factors. Prognostic classification can benefit from molecular analyses such as large-scale expression profiling. Using immunohistochemistry on tissue microarrays, we have monitored the expression of 26 selected proteins in more than 1,600 cancer samples from 552 consecutive patients with early breast cancer. Both an unsupervised approach and a new supervised method were used to analyze these profiles. Hierarchical clustering identified relevant clusters of coexpressed proteins and clusters of tumors. We delineated protein clusters associated with the estrogen receptor and with proliferation. Tumor clusters correlated with several histoclinical features of samples, including 5-year metastasis-free survival (MFS), and with the recently proposed pathophysiologic taxonomy of disease. The supervised method identified a set of 21 proteins whose combined expression significantly correlated to MFS in a learning set of 368 patients (P < 0.0001) and in a validation set of 184 patients (P < 0.0001). Among the 552 patients, the 5-year MFS was 90% for patients classified in the "good-prognosis class" and 61% for those classified in the "poor-prognosis class" (P < 0.0001). This difference remained significant when the molecular grouping was applied according to lymph node or estrogen receptor status, as well as the type of adjuvant systemic therapy. In multivariate analysis, the 21-protein set was the strongest independent predictor of clinical outcome. These results show that protein expression profiling may be a clinically useful approach to assess breast cancer heterogeneity and prognosis in stage I, II, or III disease.

Adult↗

PubMed2005

An evolutionary history of the FGF superfamily.

Fibroblast growth factors (FGF) are associated with multiple developmental and metabolic processes in triploblasts, and perhaps also in diploblasts. The evolution of the FGF superfamily has accompanied the major morphological and functional innovations of metazoan species. The study of FGFs throughout species shows that the FGF superfamily can be subdivided in eight families in present-day organisms and has evolved through phases of gene duplications and gene losses. At least two major expansions of the superfamily can be recognized: a first expansion increased the number of FGFs from one or few archeo-FGFs to eight proto-FGFs, prototypic of the eight families. A second expansion, which took place during euchordate evolution, is associated with genome duplications. It increased the number of members in the families. Subsequent losses reduced that number to the present-day figures.

Animals↗

PubMed2005

A pair as a minimum: the two fibroblast growth factors of the nematode Caenorhabditis elegans.

Fibroblast growth factors (FGFs) regulate many important developmental and homeostatic physiological events. The FGF superfamily contains several families. In this review, we present recent findings on the two FGFs of the nematode Caenorhabditis elegans from both functional and phylogenic points of view. C. elegans has a single FGFR (EGL-15) with two functionally exclusive isoforms, and two FGFs (LET-756 and EGL-17), which play distinct roles: an essential function for the former, and guidance of the migrating sex myoblasts for the latter. Regulation of homeostasis by control of the fluid balance could be the basis for the essential function of LET-756. Phylogenetic and functional studies suggest that LET-756, like vertebrate FGF9, -16, and -20, belongs to the FGF9 family, whereas EGL-17, like vertebrate FGF8, -17, and -18, could be included in the FGF8 family.

Animals↗

PubMed2005

ETV6 gene rearrangements in invasive breast carcinoma.

The ETV6/TEL gene encodes a transcription factor frequently rearranged in several types of cancer. We looked for ETV6 rearrangements in invasive breast cancer using fluorescence in situ hybridization (FISH) of BAC probes on sections of tissue microarrays containing 632 tumor samples. Of these samples, signal of sufficient quality for screening by FISH was obtained for 356. Five cases (one lobular, one nontypical secretory, one mixed, and two ductal carcinomas) showed ETV6 rearrangement.

Adenocarcinoma↗

PubMed2005

FGF6 regulates muscle differentiation through a calcineurin-dependent pathway in regenerating soleus of adult mice.

Important functions in myogenesis have been proposed for FGF6, a member of the fibroblast growth factor family accumulating almost exclusively in the myogenic lineage, but its precise role in vivo remains mostly unclear. Here, using FGF6 (-/-) mice and rescue experiments by injection of recombinant FGF6, we dissected the functional role of FGF6 during in vivo myogenesis. We found that the appearance of myotubes was accelerated during regeneration of the soleus of FGF6 (-/-) mice versus wild type mice. This accelerated differentiation was correlated with increased expression of differentiation markers such as CdkIs and calcineurin, as well as structural markers such as MHCI and slow TnI. We showed that an elevated transcript level for calcineurin Aalpha subunit correlated with a positive regulation of calcineurin A activity in regenerating soleus of the FGF6 (-/-) mice. Cyclin D1 and calcineurin were up- and down-regulated, respectively in a dose-dependent manner upon injection of rhFGF6 in regenerating soleus of the mutant mice. We showed an increase of the number of slow oxidative (type I) myofibers, whereas fast oxidative (type IIa) myofibers were decreased in number in regenerating soleus of FGF6 (-/-) mice versus that of wild type mice. In adult soleus, the number of type I myofibers was also higher in FGF6 (-/-) mice than in wild type mice. Taken together these results evidenced a specific phenotype for soleus of the FGF6 (-/-) mice and led us to propose a model accounting for a specific dose-dependent effect of FGF6 in muscle regeneration. At high doses, FGF6 stimulates the proliferation of the myogenic stem cells, whereas at lower doses it regulates both muscle differentiation and muscle phenotype via a calcineurin-signaling pathway.

Age Factors↗