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ErbB2 Expression (erbb2 + expression)
Selected AbstractsDifferent expression of P14ARF defines two groups of breast carcinomas in terms of TP73 expression and TP53 mutational statusGENES, CHROMOSOMES AND CANCER, Issue 2 2001Gemma Domínguez In 95 breast carcinomas, we investigated P14ARF and TP73 mRNA expression and their relationship to TP53 mutations, determined by an immunohistochemical method, studying several clinicopathologic features of the tumors. P14ARF and TP73 mRNA levels were determined by semiquantitative reverse transcription polymerase chain reaction (RT-PCR), using ,-actin as a control. P14ARF was overexpressed in 19% of the cases and underexpressed in 24%. TP73 was overexpressed in 22% of the tumors, and normal levels were found in the remaining 78%. The analysis of TP53 showed positive immunostaining in 38% of cases. The association of P14ARF and TP73 overexpression was statistically significant, as was the association between positive TP53 staining and TP73 overexpression. P14ARF was related to TP53 only in those cases in which there was low expression of P14ARF. Concomitant overexpression of P14ARF and TP73 was statistically related to positive TP53 immunostaining. The analysis of concomitant P14ARF and TP73 overexpression and clinicopathologic parameters of the tumors showed a statistically significant difference with respect to peritumoral vessel invasion (P = 0.01), lymph node metastasis (P = 0.03), negative ERBB2 expression (P = 0.005), and more advanced pathologic stages (P = 0.03). These results suggest that overexpression of P14ARF and TP73 could be implicated in breast carcinoma tumorigenesis and, ultimately, in the phenotypic features of these lesions. © 2001 Wiley-Liss, Inc. [source] Induction or suppression of expression of cytochrome C oxidase subunit II by heregulin , 1 in human mammary epithelial cells is dependent on the levels of ErbB2 expressionJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2002Yanbo Sun The ErbB family of receptor kinases is composed of four members: epidermal growth factor receptor (EGFR/ErbB1), ErbB2/neu, ErbB3, and ErbB4. Amplification of the ErbB2/neu is found in about 30% of breast cancer patients and is associated with a poor prognosis. Heregulin (HRG) activates the ErbB2 via induction of heterodimerization with ErbB3 and ErbB4 receptors. With suppression subtractive hybridization, we demonstrated that the expression of cytochrome c oxidase subunit II (COXII) is HRG-responsive. Two nontransformed human mammary epithelial cell lines, the HB2 and the HB2ErbB2 (the HB2 engineered to overexpress ErbB2), displayed an opposite response to HRG-mediated regulation. HRG upregulated mRNA expression of COXII in the HB2 cells, but suppressed COXII expression in the HB2ErbB2 cells. A human breast cancer cell line (T47D), which expresses ErbB2 at a level similar to that of the HB2 cells, also responded to HRG by increasing COXII mRNA levels. Therefore, HRG regulation of COXII expression depends on the levels of ErbB2 expression. Furthermore, the expression of COXII was inversely correlated to the levels of ErbB2, i.e., the cells overexpressing ErbB2 exhibited lower COXII levels. HRG-evoked signal transduction differed between the cells with normal ErbB expression and the cells overexpressing ErbB2. The activation of both ERK and PI3-K was essential for HRG regulation of COXII, i.e., blockage of either pathway eliminated HRG-mediated alteration. This is the first report demonstrating that the expression of mitochondria-encoded COXII is HRG-responsive. The levels of ErbB2 expression are decisive for the diverse biological activities of HRG. © 2002 Wiley-Liss, Inc. [source] ErbB2 and EGFR are downmodulated during the differentiation of 3T3-L1 preadipocytes,,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2003Eleonora Pagano Abstract The expression of receptors belonging to the epidermal growth factor receptor subfamily has been largely studied these last years in epithelial cells mainly as involved in cell proliferation and malignant progression. Although much work has focused on the role of these growth factor receptors in the differentiation of a variety of tissues, there is little information in regards to normal stromal cells. We investigated erbB2 expression in the murine fibroblast cell line Swiss 3T3L1, which naturally or hormonally induced undergoes adipocyte differentiation. We found that the Swiss 3T3-L1 fibroblasts express erbB2, in addition to EGFR, and in a quantity comparable to or even greater than the breast cancer cell line T47D. Proliferating cells increased erbB2 and EGFR levels when reaching confluence up to 4- and 10-fold, respectively. This expression showed a significant decrease when growth-arrested cells were stimulated to differentiate with dexamethasone and isobutyl-methylxanthine. Differentiated cells presented a decreased expression of both erbB2 and EGFR regardless of whether the cells were hormonally or spontaneously differentiated. EGF stimulation of serum-starved cells increased erbB2 tyrosine phosphorylation and retarded erbB2 migration in SDS,PAGE, suggesting receptor association and activation. Heregulin-,1 and -,1, two EGF related factors, had no effect on erbB2 or EGFR phosphorylation. Although 3T3-L1 cells expressed heregulin, its specific receptors, erbB3 and erbB4, were not found. This is the first time in which erbB2 is reported to be expressed in an adipocytic cell line which does not depend on non EGF family growth factors (thyroid hormone, growth hormone, etc.) to accomplish adipose differentiation. Since erbB2 and EGFR expression were downmodulated as differentiation progressed it is conceivable that a mechanism of switching from a mitogenic to a differentiating signaling pathway may be involved, through regulation of the expression of these growth factor receptors. © 2003 Wiley-Liss, Inc. [source] | ||||||||||