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)

A retrovirus containing a neu oncogene was introduced into a Fischer F344 rat liver epithelial cell line (WB-F344) to study the effect of the expression of neu oncoprotein on gap junctional intercellular communication (GJIC), the ability to form colonies in soft agar and the ability to form tumors in rat liver by these cells. After viral infection, five different neu-transduced epithelial clones were randomly selected for further analysis. Southern blot analysis of HindIII-digested genomic DNA hybridized with a neu-specific probe indicated that the neu oncogene carried by the retrovirus was integrated into different chromosomal locations in the five different neu-transduced WB cell lines. Using the fluorescence recovery after photobleaching (FRAP) assay, we found that GJIC was significantly reduced in neu-transduced WB clones, compared with control virus-infected and parental WB cells. Western blot analysis of connexin 43 in the neu-transduced cell lines showed altered phosphorylation patterns compared with the normal WB-rat liver cell line. Confocal image analysis of the neu-transduced cells showed that the connexin 43 protein, as detected by fluorescent immunostaining, was localized in the cell nucleus. The neu-transduced WB cell lines also acquired the ability to grow in soft agar. Furthermore, cells from three of the five neu-transduced cell lines, when injected into the liver of Fischer F344 rats through the portal vein, were highly tumorigenic (multiple focal hepatic tumors developed within 2 weeks). Cells derived from the tumor were shown to be G-418 resistant, demonstrating that the tumor was derived from the injected WB-neu cells. The results of this study demonstrate that the expression of the neu oncogene is able to block GJIC and to induce tumorigenicity in the rat liver WB-F344 cell line.
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PMID:Inhibition of gap junctional intercellular communication and malignant transformation of rat liver epithelial cells by neu oncogene. 785 63

Clones of rat liver epithelial cells genotypically altered by mutation or by a variety of oncogenes were analyzed by microinjection-dye transfer, immunofluorescence confocal microscopy, and western blotting to determine at what level and to what degree these transformations disrupted gap-junctional intercellular communication (GJIC) mediated by connexin 43 (Cx43). Compared with normal rat liver epithelial cells, cells neoplastically transformed by src, neu, ras, and myc/ras all displayed reduced degrees of GJIC, reduced levels of membrane-associated Cx43 plaques, and hypophosphorylation of Cx43. Confocal analysis further demonstrated that the Cx43 protein was localized, at least in part, to the nucleus rather than to the plasma membrane in the src- and neu-transformed cells, but not in the ras- and myc/ras-transformed cells. Nuclei isolated from WB-neu cells showed substantially higher levels of Cx43 on western blotting than did nuclei from WB-neo control cells, supporting the idea that the nuclear-localized immunopositive material detected by confocal microscopy was Cx43 protein. In a GJIC-deficient mutant rat liver epithelial cell line containing normal numbers of plasma membrane-localized Cx43 plaques that appeared to be reduced in size, the Cx43 protein was also found to be hypophosphorylated. Cells overexpressing myc, on the other hand, displayed a normal degree of GJIC, increased levels of plasma membrane-localized Cx43 plaques, and hyperphosphorylation of the Cx43 protein. Cells expressing raf, previously shown to be GJIC competent, showed Cx43 immunostaining patterns similar to those in normal cells, whereas a cell line established from a tumor induced by injection of these raf-expressing cells into a mouse showed a marked reduction in GJIC and plasma membrane-associated Cx43 immunostaining. These data suggest that altered localization of the gap-junction protein Cx43, mediated in part by changes in the phosphorylation of this protein, contributes to the disruption of GJIC in neoplastically transformed rat liver epithelial cells.
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PMID:Localization and function of the connexin 43 gap-junction protein in normal and various oncogene-expressing rat liver epithelial cells. 878 63

Several lines of evidence suggest that stem cells are major targets for carcinogens. A normal human breast epithelial cell type was previously shown to possess stem cell characteristics. Further cell lines were derived following sequential transfection with SV40 large T-antigen (immortal, non-tumorigenic M13SV1 cells), exposure to X-rays (weakly tumorigenic M13SV1R2 cells), and ectopic expression of c-erbB2/neu (highly tumorigenic M13SV1R2N1 cells). We evaluated some characteristics of these cells and their susceptibility to the breast carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). Compared to M13SV1 cells, the two untreated tumorigenic cell lines displayed higher levels of connexin 43 expression and NF-kappaB nuclear translocation, and a higher frequency of fhit loss. The baseline nuclear translocation of AP-1 and pCREB was particularly evident in M13SV1R2N1 cells and was further enhanced by DMBA treatment, indicating an interaction between c-erbB2/neu and DMBA-induced signalling. Treatment with DMBA did neither affect the baseline fhit loss nor p53 mutation, whereas it increased NF-kappaB nuclear translocation, the proportion of apoptotic cells, and the levels of connexin 43, common 4977-bp mitochondrial DNA deletion, and bulky adducts to nuclear DNA. DMBA-treated M13SV1 cells underwent significant oxidative DNA damage and exhibited the highest DNA adduct levels, while they had the lowest apoptotic rate. Co-treatment of cells with N-acetylcysteine (NAC) attenuated DMBA-induced toxicity and DNA alterations, particularly in M13SV1 cells. Thus, the immortal cell line derived from the normal human adult breast stem cell without further tumorigenic progression is the most susceptible both to DMBA-related alterations and to the protective effects of NAC.
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PMID:Induction by 7,12-dimethylbenz(a)anthracene of molecular and biochemical alterations in transformed human mammary epithelial stem cells, and protection by N-acetylcysteine. 1686 67