Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum-free mouse embryo cells, cultured in basal nutrient medium supplemented with insulin, transferrin, epidermal growth factor, fibronectin, and high-density lipoprotein, do not exhibit growth crisis, lack detectable chromosomal aberrations, are nontumorigenic in vivo, are dependent on epidermal growth factor for survival, and are growth inhibited by serum or platelet-free plasma. These cells after transfection with the human Ha-ras or rat neu oncogenes no longer required epidermal growth factor for survival, were tumorigenic in vivo, and also proliferated in serum-containing medium. Autocrine activity capable of replacing epidermal growth factor was detected in conditioned medium from ras-transformed cultures, but little such activity was detected in medium from neu-transformed cultures. In addition, the capability of ras or neu-transformed cells to grow in serum-containing medium could not be mimicked in untransformed cells by the addition of growth factors or conditioned medium from transformed cells. These results suggest that the known structural similarity of the neu gene product to the EGF receptor is also reflected in a functional similarity by which the mutationally activated neu protein can replace the ligand-activated EGF receptor. These results also suggest that the ability of ras- and neu-transformed cells to escape the effect of the inhibitory serum activity is a nonautocrine property distinct from the acquisition of EGF autonomy.
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PMID:ras and neu oncogenes reverse serum inhibition and epidermal growth factor dependence of serum-free mouse embryo cells. 197 70

Neonatal rat hepatocytes (NRH) in primary cultures were transformed upon transfection with plasmid pSV 5-neo containing polyoma virus (Py) early region sequences. Clones of cells (Py-NRH) resistant to the antibiotic G418 were obtained after selection in arginine-deficient medium with serum, epidermal growth factor (EGF), transferrin and insulin. They did not undergo senescence during serial subcultivation. One clone (Py-NRH Cl A) harbored a single integrated copy of Py early region sequences and expressed transforming Py genes, hepatocyte-specific transcripts, including albumin, alpha-fetoprotein (AFP) and tyrosine aminotransferase (TAT) mRNAs. Subclones isolated after about 45 cell doublings still contained albumin and AFP, but no TAT mRNAs, indicating that long-term stabilization of liver functions is not necessarily permanent unless selected for (e.g. arginine synthesis). Cells grew unrestricted in medium containing insulin and no longer required EGF. Cells grew in agar, secreted a beta-transforming growth factor-like activity into the medium and were tumorigenic in nude mice. Hybridization studies using v-erbB DNA as a probe showed that Py-NRH, unlike neonatal hepatocytes in primary culture, express the EGF receptor gene at low or undetectable levels. Py-NRH Cl A and a subclone (5A) derived from it, however, contained elevated levels of rat c-neu oncogene-related RNA, whereas levels in another subclone (3A) were low or undetectable. These findings demonstrate that a proto-oncogene was activated after transfection of hepatocytes with DNA tumor virus transforming genes. However, the expression of c-neu oncogene is not related to the maintenance of the transformed state.
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PMID:Transformation of differentiated neonatal rat hepatocytes in primary culture by polyoma virus early region sequences. 283 82

We have previously shown that each of four activated oncogenes (c-myc, neu, ras, and int-2) can serve as transgenic initiators of morphologically distinct adenocarcinomas of the murine mammary gland. Since abnormalities of these oncogenes are found frequently in human breast cancers, such differences are of particular interest. Thus, the distinctiveness of each murine tumor type might reflect a relationship between a specific oncogene and a susceptible target cell or might reflect distinctive changes brought about by the idiosyncratic action of each oncogene. We have identified six genes (two of them novel) expressed in tumors initiated by neu, but usually absent from tumors initiated by c-myc. The expression of these genes (kappa-casein, transferrin, cellular retinol binding protein I (CRBPI), WDNM1, and the two novel ones) cannot be induced in c-myc-initiated tumors by the introduction of an activated neu oncogene nor can their expression be inhibited in neu-initiated tumors by the introduction of c-myc. Therefore, these genes appear to represent markers of a cell type preferentially transformed by neu. Further analysis reveals that the six markers are also expressed by ras-initiated mammary tumors, but not by int-2-initiated tumors suggesting that neu/ras-initiated tumors share a common cellular lineage and/or a common signal transduction pathway. Interestingly, one of the novel marker genes (Mat-8) appears to encode a cell-surface chloride channel and the other, a secreted protein with homologies to glycosyl hydrolases, both of which might be useful for the diagnosis and treatment of specific mammary tumors.
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PMID:neu and ras initiate murine mammary tumors that share genetic markers generally absent in c-myc and int-2-initiated tumors. 797 Jul

Liposomes (70-100 nm) of 1-palmitoyl-2-oleoylphosphatidylcholine, cholesterol, and poly(ethylene glycol) (PEG)-modified phosphatidylethanolamine (PEG-DSPE) were conjugated to Fab' fragments of a humanized recombinant MAb against the extracellular domain of HER2/neu to create sterically stabilized immunoliposomes (anti-HER2 SL) as a drug carrier targeting HER2-overexpressing cancers. Conjugation employed maleimide-terminated membrane-anchored spacers of two kinds: a short spacer, providing attachment of Fab' close to the liposome bilayer, or a long spacer, with Fab' attachment at the distal terminus of the PEG chain. Confocal microscopy and spectrofluorometry of HER2-overexpressing breast cancer cells incubated with fluorescently labeled anti-HER2 SL prepared with either spacer showed binding of liposomes (8000-23000 vesicles/cell) followed by endocytosis (rate constant ke = 0.012-0.033 min-1) via the coated-pit pathway, evidenced by intracellular acidification and colocalization with transferrin. Uptake of anti-HER2 immunoliposomes by breast cancer cells with low HER2 expression, or after preincubation of cells with free anti-HER2 Fab', was less than 0.2% and 4.3%, respectively, of the uptake by HER2-overexpressing cells. Increasing PEG-DSPE content (up to 5.7 mol %) in anti-HER2-SL prepared with the short spacer decreased liposome-cell binding affinity 60-100-fold, while ke decreased only 2-fold; however, when Fab' fragments were conjugated via a PEG spacer, both binding affinity and ke were unaffected by PEG-DSPE content. Cell binding and internalization of anti-HER2 immunoliposomes increased at higher surface density of conjugated Fab' fragments, reaching plateaus at approximately 40 Fab'/liposome for binding and approximately 10-15 Fab'/liposome for internalization. Uptake of anti-HER2 immunoliposomes correlated with the cell surface density of HER2 and significantly (p < 0.005) correlated with the antiproliferative effect of the targeting antibody but not with the total level of cellular HER2 expression. The results obtained were used to optimize in vivo preclinical studies of anti-HER2 SL loaded with antineoplastic drugs.
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PMID:Sterically stabilized anti-HER2 immunoliposomes: design and targeting to human breast cancer cells in vitro. 899 19

A chemically defined culture medium was developed to support the growth of two distinctly different types of normal human breast epithelial cells (HBEC) derived from reduction mammoplasty. Type I cells expressed luminal epithelial cell markers and were deficient in gap junctional intercellular communication (GJIC), whereas Type II cells expressed basal epithelial cell markers and were efficient in GJIC. In this study, we examined and compared the growth factor and hormone requirements of these two types of cells and a series of cell lines that were obtained by sequential transfection with SV40 DNA (extended lifespan, nontumorigenic), treatment with 5-bromodeoxyuridine (BrdU)/black light (immortal and weakly tumorigenic), and infection of a virus carrying the neu oncogene (highly tumorigenic). Growth of Type I cells was inhibited by withdrawing epidermal growth factor (EGF), hydrocortisone (HC), or insulin (INS) from the culture media, but was enhanced by fetal bovine serum (FBS) supplementation. Growth of Type II cells was inhibited by withdrawal of EGF, HC, or INS from the media, and was inhibited by FBS supplementation. Withdrawal of human transferrin (HT) or 17 beta-estradiol (E2) from the media did not alter the growth of Type I or Type II cells. SV40 transfected Type I cell lines still required EGF, HC, or INS for optimal growth. However, the highly tumorigenic cell line did not show a growth dependence on EGF, HC, or INS but did appear to require HT and 3,3',5-triiodo-D.L. thyronine (T3) for optimal growth. In addition, FBS stimulated the growth of these cell lines. Thus, this study shows that Type I HBEC are distinctly different from Type II HBEC in growth response to FBS and that neoplastically transformed Type I cells could become growth factor and hormone independent.
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PMID:Growth requirements and neoplastic transformation of two types of normal human breast epithelial cells derived from reduction mammoplasty. 915 44

Interactions between (mesenchymal) peritubular myoid cells and (epithelial) Sertoli cells play an important role in the control of Sertoli cell function and spermatogenesis. The factors involved, however, have only partially been identified. Heregulins or neu differentiation factors (NDFs) mediate mesenchymal-epithelial interactions in a variety of tissues, but their role in the testis has not been investigated. Here we demonstrate that recombinant human heregulin-alpha (Her-alpha) and Her-beta stimulate transferrin and androgen-binding protein production by cultured rat Sertoli cells up to 2.5-fold. These effects are more pronounced than those of previously identified growth factors active in this assay, such as insulin-like growth factor I and basic fibroblast growth factor. Combination with these factors results in additive effects and in marked morphological changes in the Sertoli cell cultures, including formation of tubule-like structures. Stimulation of androgen-binding protein secretion is paralleled by increased levels of the corresponding messenger RNA. This parallelism was less consistent for transferrin. Semiquantitative RT-PCR indicates that the expression of NDF-alpha and NDF-beta is more pronounced in peritubular cells than in Leydig or Sertoli cells. Conversely, the main receptors for heregulins/NDFs, HER-3 and HER-4, are predominantly expressed in Sertoli cells. A displacement assay confirms the presence of high-affinity binding sites for [125I]Her-beta on intact Sertoli cells and reveals parallel displacement curves for Her-beta, Her-alpha, and concentrated peritubular cell-conditioned medium (PTCM; estimated ED50 values: 1 ng/ml, 50 ng/ml, and 130 microg protein/ml, respectively), indicating that peritubular cells secrete one or more factors able to compete for heregulin receptors. It is concluded that heregulins/NDFs may play a role in mesenchymal-epithelial interactions in the testis. Estimates of the concentrations of heregulins in PTCM, however, make it unlikely that they contribute significantly to the effects observed with low concentrations of PTCM and ascribed to the putative mediator PModS (peritubular factor that modulates Sertoli cell function). Further investigations will be required to define the exact role of heregulins in the testis.
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PMID:Heregulins or neu differentiation factors and the interactions between peritubular myoid cells and Sertoli cells. 1021 74

Oligodendrocytes (OLs), the myelin-producing cells of the central nervous system, segregate different surface subdomains at the plasma membrane as do other differentiated cells such as polarized epithelia and neurons. To generate the complex membrane system that characterizes myelinating OLs, large amounts of membrane proteins and lipids need to be synthesized and correctly targeted. In polarized epithelia, a considerable fraction of apical proteins are transported by an indirect pathway involving a detour to the basolateral membrane before being internalized and transported across the cell to the apical membrane by a process known as transcytosis. The apical recycling endosome (ARE) or its equivalent, the subapical compartment (SAC), of hepatocytes is an intracellular trafficking station involved in the transcytotic pathway. MAL2, an essential component of the machinery for basolateral-to-apical transcytosis, is an ARE/SAC resident protein. Here, we show that, after differentiation, murine oligodendrocyte precursor and human oligodendroglioma derived cell lines, Oli-neu and HOG, respectively, up-regulate the expression of MAL2 and accumulate it in an intracellular compartment, exhibiting a peri-centrosomal localization. In these oligodendrocytic cell lines, this compartment shares some of the main features of the ARE/SAC, such as colocalization with Rab11a, sensitivity to disruption of the microtubule cytoskeleton with nocodazole, and lack of internalized transferrin. Therefore, we suggest that the MAL2-positive compartment in oligodendrocytic cells could be a structure analogous to the ARE/SAC and might have an important role in the sorting of proteins and lipids for myelin assembly during oligodendrocyte differentiation.
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PMID:Characterization of the MAL2-positive compartment in oligodendrocytes. 1968 24