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Human Mammary Epithelial Cells (human + mammary_epithelial_cell)
Kinds of Human Mammary Epithelial Cells Selected AbstractsCentrosome amplification induced by the antiretroviral nucleoside reverse transcriptase inhibitors lamivudine, stavudine, and didanosineENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 8 2009Mia Yu Abstract In cultured cells, exposure to the nucleoside reverse transcriptase inhibitor (NRTI) zidovudine (AZT) induces genomic instability, cell cycle arrest, micronuclei, sister chromatid exchanges, and shortened telomeres. In previous studies, we demonstrated AZT-induced centrosome amplification (>2 centrosomes/cell). Here, we investigate centrosome amplification in cells exposed to other commonly used NRTIs. Experiments were performed using Chinese Hamster ovary (CHO) cells, and two normal human mammary epithelial cell (NHMEC) strains: M99005 and M98040, which are high and low incorporators of AZT into DNA, respectively. Cells were exposed for 24 hr to lamivudine (3TC), stavudine (d4T), didanosine (ddI), and thymidine, and stained with anti-pericentrin antibody. Dose response curves were performed to determine cytotoxicity and a lower concentration at near plasma levels and a 10 fold higher concentration were chosen for the experiments. In CHO cells, there was a concentration-dependent, significant (P < 0.05) increase in centrosome amplification for each of the NRTIs. In NHMEC strain M99005, an NRTI-induced increase (P < 0.05) in centrosome amplification was observed for the high concentrations of each NRTI and the low doses of 3TC and ddI. In NHMEC strain M98040, the high doses of ddI and d4T showed significant increases in centrosome amplification. Functional viability of amplified centrosomes was assessed by arresting microtubule nucleation with nocodazole. In cells with more than two centrosomes, the ability to recover microtubule nucleation was similar to that of unexposed cells. We conclude that centrosome amplification is a consequence of exposure to NRTIs and that cells with centrosome amplification are able to accomplish cell division. Environ. Mol. Mutagen., 2009. © 2009 Wiley-Liss, Inc. [source] Loss of RAB25 expression in breast cancerINTERNATIONAL JOURNAL OF CANCER, Issue 12 2006Ji-Ming Cheng Abstract A novel breast cancer cell line (RAO-3) was established by transduction of the Q61L mutant RAS into human mammary epithelial cells that were immortalized with catalytic subunit of telomerase (hTERT). The cells displayed anchorage-independent growth and proliferation, and formed human mammary spindle cell carcinoma when injected into nude mice. Chromosome locus 1q22-23 was partially duplicated and inverted on one of the 3 chromosomes present in the cell line. We report here that mutations of chromosome 1q22-23 locus have resulted in the loss of RAB25 expression in the breast cancer cell line. Transduction of RAB25 into the breast cancer cell line arrests anchorage-independent growth. We have also demonstrated loss of RAB25 in human breast tumor tissue. These data suggest that loss of RAB25 might contribute to tumorigenesis of breast cancer, and RAB25 is likely to be an important factor in the development of breast cancer. RAB25 could be used as biological marker of breast cancer and provides a target for gene replacement therapy. © 2006 Wiley-Liss, Inc. [source] TCDD causes suppression of growth and differentiation of MCF10A, human mammary epithelial cells by interfering with their insulin receptor signaling through c-Src kinase and ERK activationJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2005Sujin Park Abstract One of the proposed mechanisms of carcinogenic action of TCDD (=dioxin) on breast cells is that it causes significant inhibition of proper differentiation of mammary duct epithelial cells and thereby increases the number of terminal end buds, which are susceptible to other carcinogens (Fenton et al., Toxicol Sci 2002;67:63,74; Brown et al., Carcinogenesis 1998; 19:1623,1629; Lamartiniere, J Mammary Gland Biol Neoplasia 2002;7:67,76). To address this topic, we selected MCF10A, a line of immortalized normal human breast epithelial cells as an in vitro model. An initial effort was made to optimize the cultural condition of MCF10A cells to promote the cell differentiation effect of insulin. Under this condition, TCDD clearly antagonized the action of insulin only in the presence of cholera toxin that is known to promote the differentiation of normal human breast epithelial cells. To test the hypothesis that TCDD-induced c-Src kinase activation is casually related to this compound's antagonistic action against insulin, we treated MCF10A cells with two c-Src blocking agents, an anti-Src antisense oligonucleotides blocker and a known specific inhibitor of c-Src kinase, PP-2 and studied the effect of insulin and TCDD on cell proliferation. The results showed that, in cells treated with either of these two c-Src blocking agents, the antagonistic effect of TCDD disappeared. It was also found that agents which specifically block the activation of ERK could also abrogate the action of TCDD to suppress insulin signaling. Together, these results indicate that the mechanism of the antagonistic action of TCDD on insulin signaling is mainly mediated through c-Src signaling through activation of ERK. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:322,331, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20040 [source] Retinoic acid induces expression of the interleukin-1, gene in cultured normal human mammary epithelial cells and in human breast carcinoma linesJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2002Limin Liu Retinoic acid (RA) and its derivatives inhibit the proliferation of normal human mammary epithelial cells (HMEC) and some breast carcinoma lines by mechanisms which are not fully understood. To identify genes that mediate RA-induced cell growth arrest, an HMEC cDNA library was synthesized and subtractive screening was performed. We identified the interleukin-1, (IL-1,) gene as an RA induced gene in HMEC. Northern blot analyses showed that the IL-1, gene was up-regulated as early as 2 h after RA treatment. Results from the treatment of HMEC with cycloheximide and actinomycin D indicated that the regulation of the IL-1, gene by RA occurred at the transcriptional level and that the IL-1, gene is a direct, downstream target gene of RA. To evaluate the effects of IL-1, on cell proliferation, the proliferation of HMEC was measured in the presence of RA or IL-1,, or both. Either RA or IL-1, could significantly inhibit the proliferation of HMEC. However, the addition of soluble IL-1 receptor antagonist (sIL-1ra) to the cell culture medium did not block RA-induced HMEC growth inhibition, whereas sIL-1ra did block the growth inhibition of HMEC by IL-1,. IL-1, expression was not observed in the three carcinoma cell lines, MCF-7, MDA-MB-231, and MDA-MB-468, as compared to the HMEC. Growth curves of the breast carcinoma cell lines showed strong inhibitory effects of RA and IL-1, on the growth of the estrogen receptor (ER) positive MCF-7 cell line, but only a small effect on the ER negative MDA-MB-231 cells. The expression of the IL-1, gene was also transcriptionally activated by RA in normal epithelial cells of prostate and oral cavity. Our results suggest that: (a) the IL-1, gene is a primary target of RA receptors in HMEC; (b) the enhanced expression of the IL-1, gene does not mediate the RA-induced growth arrest of HMEC; and (c) the expression of the IL-1, gene is low or absent in all three human breast carcinoma cell lines examined, but the defect in the IL-1, signaling pathway may be different in ER positive versus ER negative carcinoma cells. © 2002 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] Retinoids and retinoic acid receptors regulate growth arrest and apoptosis in human mammary epithelial cells and modulate expression of CBP/p300MICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2002Eric C. Dietze Abstract Retinoids and retinoic acid receptors (RARs) are important mediators of normal epithelial cell homeostasis. To assess the role of retinoids and RARs in regulating growth arrest and apoptosis in benign and malignant mammary epithelial cells, two model systems were developed: 1) RAR function was suppressed in retinoid-sensitive normal human mammary epithelial cells (HMECs) by the dominant-negative retinoic acid receptor, RAR,403 (DNRAR), and 2) retinoid-resistant MCF-7 breast cancer cells were transduced with a functional RAR,2. Inhibition of RAR function by the DNRAR in HMECs resulted in retinoid-resistance, increased proliferation, and dysregulated growth when cells were cultured in reconstituted extracellular matrix (rECM). Expression of RAR,2 in MCF-7 cells resulted in sensitivity to retinoid-induced growth arrest and apoptosis. The CREB-binding protein (CBP) and the homologous protein p300 are tightly regulated, rate-limiting integrators of diverse signaling pathways and are recruited during retinoid-mediated transcriptional activation. The relationship between retinoid receptor expression, growth regulation, and transcriptional regulation of CBP/p300 is poorly understood. Inhibition of RAR function in HMECs by DNRAR suppressed expression of CBP/p300 and expression of RAR,2 in MCF-7 cells promoted induction of CBP/p300 when cells were treated with 1.0 ,M all- trans -retinoic acid (ATRA). These results suggest that ATRA and RARs regulate growth arrest of HMECs and modulate CBP/p300 protein expression. Since CBP and p300 are normally present in limiting amounts, their regulation by ATRA and RARs may be an important element in the control of transcriptional activation of genes regulating growth arrest and apoptosis. Microsc. Res. Tech. 59:23,40, 2002. © 2002 Wiley-Liss, Inc. [source] Improved proteome coverage by using high efficiency cysteinyl peptide enrichment: The human mammary epithelial cell proteomePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2005Tao Liu Abstract Automated multidimensional capillary liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been increasingly applied in various large scale proteome profiling efforts. However, comprehensive global proteome analysis remains technically challenging due to issues associated with sample complexity and dynamic range of protein abundances, which is particularly apparent in mammalian biological systems. We report here the application of a high efficiency cysteinyl peptide enrichment (CPE) approach to the global proteome analysis of human mammary epithelial cells (HMECs) which significantly improved both sequence coverage of protein identifications and the overall proteome coverage. The cysteinyl peptides were specifically enriched by using a thiol-specific covalent resin, fractionated by strong cation exchange chromatography, and subsequently analyzed by reversed-phase capillary LC-MS/MS. An HMEC tryptic digest without CPE was also fractionated and analyzed under the same conditions for comparison. The combined analyses of HMEC tryptic digests with and without CPE resulted in a total of 14,416 confidently identified peptides covering 4294 different proteins with an estimated 10%,gene coverage of the human genome. By using the high efficiency CPE, an additional 1096 relatively low abundance proteins were identified, resulting in 34.3% increase in proteome coverage; 1390,proteins were observed with increased sequence coverage. Comparative protein distribution analyses revealed that the CPE method is not biased with regard to protein Mr,, pI, cellular location, or biological functions. These results demonstrate that the use of the CPE approach provides improved efficiency in comprehensive proteome-wide analyses of highly complex mammalian biological systems. [source] Latent transforming growth factor binding protein 4 (LTBP-4) is downregulated in human mammary adenocarcinomas in vitro and in vivo,APMIS, Issue 6 2007SUSANNE MAUEL Transforming growth factor beta (TGF-ß) is able to inhibit proliferation of epithelial cells and is involved in the carcinogenesis of human mammary tumours. Three latent transforming growth factor-ß binding proteins (LTBP-1, -3 and -4) are involved in TGF-ß function. The aim of the study was to analyze the expression profiles of TGF-ß 1 and 2 and LTBP-4 in human mammary carcinoma cell lines as well as in human mammary tumours. Expression analysis was performed at the transcription and protein level under in vivo and in vitro conditions. LTBP-4 expression was quantitatively analysed in human carcinomas of the mammary gland and in healthy mammary tissues of the same patients. Downregulation of LTBP-4 in all investigated human mammary tumours compared to normal tissues could be demonstrated. Results also revealed that protein levels of TGF-ß 1 are downregulated and of TGF-ß 2 are upregulated in human mammary carcinoma cell lines compared to primary (normal) human mammary epithelial cells. LTBP-4 reduction in neoplasms leads to a possible decrease of TGF-ß 1 extracellular deposition with reduced TGF-ß 1 bioavailability. TGF-ß 2 was upregulated, which indicates a possible compensatory mechanism. This study demonstrated a possible functional role of LTBP-4 for TGF-ß bioavailability with respect to carcinogenesis of human mammary tumours in vivo and in vitro. [source] | ||||||||||||||||