Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have tested the sensitivity of human MCF-10A mammary epithelial cells and of their transformed derivatives overexpressing an activated c-Ha-ras gene (MCF-10A Ha-ras cells), the c-erbB-2 gene (MCF-10A c-erbB-2 cells) or both genes (MCF-10A HE cells) to different cytotoxic drugs. As compared with parental MCF-10A cells, the transformed cells exhibited an increased sensitivity to topoisomerase I- and topoisomerase II-inhibitors, and to platinum-derivatives with a 2- to 10-fold reduction in IC(50) values. A remarkable difference in sensitivity was observed following treatment with taxanes. While MCF-10A Ha-ras cells showed an increased sensitivity, MCF-10A c-erbB-2 and MCF-10A HE cells exhibited a relative resistance to taxol and taxotere, with an approximately 3.5- to 6.5-fold higher IC(50) as compared with MCF-10A cells suggesting that c-erbB-2 overexpression has a dominant effect compared with an activated c-Ha-ras gene. The type I cAMP-dependent protein kinase (PKAI) is overexpressed in cancer cells. Inhibition of PKAI by antisense oligonucleotides targeting its RIalpha regulatory subunit results in cancer cell growth inhibition. To evaluate the effect of blocking PKAI on MCF-10A cell sensitivity to taxanes, we treated these cells with taxol or taxotere in combination with a PKAI antisense oligonucleotide. Treatment with this agent, but not with a control scramble sequence, was able to overcome the effect of c-erbB-2 overexpression on MCF-10A cell sensitivity to taxol and taxotere, with a 20- to 40-fold shift in the IC(50) values for the 2 drugs.
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PMID:Resistance to taxanes is induced by c-erbB-2 overexpression in human MCF-10A mammary epithelial cells and is blocked by combined treatment with an antisense oligonucleotide targeting type I protein kinase A. 1069 53

To investigate the relationship between oncogene activation and induction of micronuclei by a new non-peptidic mimetic farnesyltransferase inhibitor, RPR-115135, two isogenic cell lines, human colon cancer line HCT-116, which harbors a K-ras mutation, and spontaneously immortalized human breast epithelial cell line MCF-10A, were utilized. HCT-116 cells were transfected with an empty control pCMV vector (clone CMV-2) or with a dominant negative mutated p53 transgene (clone Mu-p53-2) to disrupt p53 function. In both clones RPR-115135 induced a significant increase in the frequency of micronucleation at concentrations that did not affect cell membrane integrity. RPR-115135 produced a significant increase in the ratio of CREST+ to CREST- micronuclei. MCF-10A cells were stably transfected with either c-Ha-ras or c-erbB-2 or both H-ras + c-erbB-2. No induction of micronuclei was observed. No induction of micronuclei was reported in human lymphocytes and in primary spinal cells obtained from 7-day chick embryos. In conclusion, RPR-115135 acts as an aneugenic agent in a complex manner, dependent upon the complement of mutations in cell regulatory genes in tumour cells and this activity may be independent of ras genotype.
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PMID:Induction of micronuclei by a new non-peptidic mimetic farnesyltransferase inhibitor RPR-115135: role of gene mutations. 1150 42

Tumor cells traverse the basement membrane zone and gain access to the underlying mesenchyme to eventually form metastases. Laminin 5 is a major component of the basement membrane and connects keratinocytes at the level of hemidesmosomes to the mesenchyme. Underneath invading tumor cells anti-laminin 5 staining is diminished, and laminin 5 degradation products can stimulate cell migration and epidermal growth factor (EGF) receptor signaling. To investigate laminin 5 expression in parental HaCaT and tumorigenic c-Ha-ras-transformed HaCaT II-4rt keratinocytes, the cells were cultivated under monolayer and organotypic culture conditions. In monolayer cultures, HaCaT and c-Ha-ras-transformed HaCaT II-4rt keratinocytes secreted comparable amounts of laminin 5. After 7 days of organotypic cultures, collagen IV, beta4-integrin, nidogen and laminin 5 were detected along the epithelial-mesenchymal interface of parental HaCaT keratinocytes, while staining for these proteins was patchy or absent in the organotypic cultures with c-Ha-ras-transformed HaCaT II-4rt cells. Immunoblotting analysis confirmed absence of laminin 5 deposition in organotypic cultures of c-Ha-ras-transformed HaCaT II-4rt while the protein was detected in organotypic cultures of HaCaT keratinocytes. Surprisingly, however, the alpha3 and gamma2 laminin chain transcripts were strongly induced in c-Ha-ras-transformed HaCaT II-4rt cells by organotypic culture conditions, indicating that invasive epidermal tumor cells retain high mRNA levels for laminin 5 chains and suggesting an autocrine/paracrine induction of the laminin chain mRNAs. Moreover, as laminin 5 was absent in organotypic cultures of c-Ha-ras-transformed HaCaT II-4rt cells, it suggests immediate degradation of the protein. Degradation products may further contribute to the malignant phenotype by enhancing cellular migration and EGF-receptor activation.
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PMID:Expression of laminin 5 by parental and c-Ha-ras-transformed HaCaT keratinocytes in organotypic cultures. 1646 Aug 39

MCF-10A cells are a spontaneously immortalized, nontransformed human mammary epithelial cell line that contains two normal p53 alleles and produces a normal p53 protein. We have recently shown that overexpression of several genes that are important for normal mammary gland development and for neoplastic transformation, such as transforming growth factor alpha, c-Ha-rns or c-erbB-2, leads to in vitro transformation of these cells (Ciardiello et al: Mol Carcinogen 6: 43-52, 1992). To investigate the neoplastic potential of mutated forms of the p53 gene on MCF-10A cells, we have constructed two expression vector plasmids containing two p53 mutants that were isolated from human primary breast carcinomas. Overexpression of either mutant p53 gene confers on MCF-10A cells the ability to grow in serum-free medium in monolayer culture and to form colonies in semi-solid medium. Furthermore, to determine whether a mutated p53 gene may cooperate with a point mutated c-Ha-ras and/or the normal c-erbB-2 protooncogenes in the transformation of these cells, we generated clones of MCF-10A cells that overexpress a combination of these gene pruducts. Although these cells were able to grow with a higher cloning efficiency in soft agar, none of the cell lines was tumorigenic when injected subcutaneously into immunodeficient mice.
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PMID:Effects of mutant p53 genes on transformation of human mammary epithelial-cells. 2156 22

We reported recently that azatyrosine inhibits the growth of c-Ha-ras, c-raf or c-erbB-2-transformed NIH3T3 cells and converts the transformed cells to cells with a normal phenotype. To analyze the mode of action of azatyrosine, we examined the effects of azatyrosine on the synthesis of macromolecules. Azatyrosine had no obvious inhibitory effects on the synthesis of DNA, RNA and protein in c-erbB-2-transformed cells. Furthermore, azatyrosine inhibited cell growth but did not interrupt the cell cycle at any specific stage. Thus, the mode of action of azatyrosine appeared to be different from that of typical anticancer drugs. Moreover, we found that azatyrosine was incorporated into proteins instead of tyrosine. The simultaneous presence of a high concentration of tyrosine inhibited the conversion to a normal phenotype of transformed cells by azatyrosine. These results strongly suggest that incorporation of azatyrosine into proteins might convert the transformed cells to cells with a normal phenotype. The analysis of azatyrosine-containing proteins by two-dimensional electrophoresis revealed that the mobilities of some proteins differed from those of the corresponding tyrosine-containing proteins. An alteration in molecular structure of the proteins that include azatyrosine residues might be associated with the ability of azatyrosine to convert transformed cells to cells with a normal phenotype.
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PMID:Azatyrosine is incorporated into proteins instead of tyrosine residues, with the resultant conversion of transformed cells to cells with a normal phenotype. 2159 24


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