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MCF10A Cells (mcf10a + cell)
Selected AbstractsRoles of JNK-1 and p38 in selective induction of apoptosis by capsaicin in ras -transformed human breast epithelial cellsINTERNATIONAL JOURNAL OF CANCER, Issue 4 2003Hye-Jung Kang Abstract Efforts have been made to develop a chemoprevention strategy that selectively triggers apoptosis in malignant cancer cells. Previous studies showed that capsaicin, the major pungent ingredient of red pepper, had differential effect between normal and transformed cells. As an approach to unveil the molecular mechanism by which capsaicin selectively induces apoptosis in transformed cells, we investigated the effect of capsaicin in nontransformed and ras -transformed cells of a common origin: parental (MCF10A) and H- ras -transformed (H- ras MCF10A) human breast epithelial cells. Here, we show that capsaicin selectively induces apoptosis in H- ras -transformed cells but not in their normal cell counterparts. The capsaicin-induced apoptosis, which is dependent on ras transformation, involves the activity of DEVDase (caspase-3 like). In H - ras MCF10A cells, capsaicin treatment markedly activated c-Jun N-terminal protein kinase (JNK)-1 and p38 matigen-activated protein kinase (MAPK) while it deactivated extracellular signal-regulated protein kinases (ERKs). The use of kinase inhibitors and overexpression of dominant-negative forms of MAPKs demonstrated a role of JNK-1 and p38, but not that of ERKs, in apoptosis induced by capsaicin in H- ras -transformed MCF10A cells. Based on the present study, we propose that capsaicin selectively induces apoptosis through modulation of ras -downstream signaling molecules in ras -activated MCF10A cells. Taken in conjunction with the fact that uncontrolled ras activation is probably the most common genetic defect in human cancer cells, our finding may be critical to the chemopreventive potential of capsaicin and for developing a strategy to induce tumor cell-specific apoptosis. © 2002 Wiley-Liss, Inc. [source] Studies on the mechanism of rapid activation of protein tyrosine phosphorylation activities, particularly c-Src kinase, by TCDD in MCF10AJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 6 2005Olga Mazina Abstract While the process of the Ah receptor activation leading to cytochrome P450 induction has been well studied, the mechanism and the process through which the Ah receptor activates tyrosine kinases, within a few minutes of its ligand binding, is not known. Previously, it was reported by Tannheimer et al. (Carcinogenesis 1998; 19:1291,1297) that TCDD causes rapid induction of tyrosine phosphorylation activities in the MCF10A human mammary epithelial cell line. To study the mechanistic aspect of this phenomenon, particularly that occurs within a few minutes after administration, we first studied the effect of insulin on MCF10A under serum free conditions with added EGF. The addition of insulin induced a rapid (5 min) tyrosine phosphorylation on several 160,190 kDa proteins which was followed by significant dephosphorylation activities on these proteins by 15 min. TCDD increased the rate of tyrosine phosphorylation on those proteins but at 15 min, the level of phosphorylation was still high. When insulin and TCDD were added together, the ability of insulin to induce de-phosphorylation by 15 min disappeared. Such an action of TCDD was accompanied by an increase in the titer of the activated form of Src kinase (i.e. c-Src protein with 418 tyrosine phosphorylation), and a concomitant decrease in the level of 529 tyrosine phosphorylated form (an inactivated form). The TCDD-induced activation of c-Src could be blocked by pretreated MCF10A cells with antisense oligonucleotides against c-src or with a specific inhibitor of Src kinase, PP-2. These results support the conclusion that c-Src kinase is at least one of the earliest and the most upstream components of toxic signaling of the Ah-receptor activated by TCDD through the post-transcriptional process. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:313,321, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20041 [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] Grape seed proanthocyanidin suppression of breast cell carcinogenesis induced by chronic exposure to combined 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyreneMOLECULAR CARCINOGENESIS, Issue 5 2010Xiaoyu Song Abstract Breast cancer is the most common type of cancer among women in northern America and northern Europe; dietary prevention is a cost-efficient strategy to reduce the risk of this disease. To identify dietary components for the prevention of human breast cancer associated with long-term exposure to environmental carcinogens, we studied the activity of grape seed proanthocyanidin extract (GSPE) in suppression of cellular carcinogenesis induced by repeated exposures to low doses of environmental carcinogens. We used combined carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P), at picomolar concentrations, to repeatedly treat noncancerous, human breast epithelial MCF10A cells to induce cellular acquisition of cancer-related properties of reduced dependence on growth factors, anchorage-independent growth, and acinar-conformational disruption. Using these properties as biological target endpoints, we verified the ability of GSPE to suppress combined NNK- and B[a]P-induced precancerous cellular carcinogenesis and identified the minimal, noncytotoxic concentration of GSPE required for suppressing precancerous cellular carcinogenesis. We also identified that hydroxysteroid-11-beta-dehydrogenase 2 (HSD11B2) may play a role in NNK- and B[a]P-induced precancerous cellular carcinogenesis, and its expression may act as a molecular target endpoint in GSPE's suppression of precancerous cellular carcinogenesis. And, the ability of GSPE to reduce gene expression of cytochrome-P450 enzymes CYP1A1 and CYP1B1, which can bioactivate NNK and B[a]P, possibly contributes to the preventive mechanism for GSPE in suppression of precancerous cellular carcinogenesis. Our model system with biological and molecular target endpoints verified the value of GSPE for the prevention of human breast cell carcinogenesis induced by repeated exposures to low doses of multiple environmental carcinogens. © 2010 Wiley-Liss, Inc. [source] Precancerous carcinogenesis of human breast epithelial cells by chronic exposure to benzo[a]pyreneMOLECULAR CARCINOGENESIS, Issue 5 2008Nalin Siriwardhana Abstract To understand carcinogenesis of human breast epithelial cells induced by chronic exposure to environmental pollutants, we studied biological and molecular changes in progression of cellular carcinogenesis induced by accumulated exposures to the potent environmental carcinogen benzo[a]pyrene (B[a]P). Increasing exposures of human breast epithelial MCF10A cells to B[a]P at picomolar concentrations resulted in cellular transformation from a noncancerous stage to precancerous substages, in which cells acquired the cancerous abilities of a reduced dependence on growth factors, anchorage-independent growth, and disruption in acini formation on reconstituted basement membranes. Using cDNA microarrays, we detected seven upregulated genes related to human cancers in B[a]P-transformed MCF10A cells. Using this model, we verified that green tea catechin significantly (P,<,0.05) suppressed B[a]P-induced carcinogenesis. Our studies indicate that this cellular model may serve as a cost-efficient, in vitro system, mimicking the chronic carcinogenesis of breast cells that likely occurs in early stages of carcinogenesis in vivo, to identify agents that inhibit cellular carcinogenesis. © 2007 Wiley-Liss, Inc. [source] Positioning, displacement, and localization of cells using ultrasonic forcesBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2005Albrecht Haake Abstract This paper presents a method and a device to position and displace cells. The cells are suspended in a fluid layer trapped between the device and an arbitrary surface such as an object slide or a wafer. The device vibrates at ultrasonic frequencies causing a pressure field in the fluid layer. This pressure field results in a force-field capable of positioning cells. Depending on the way in which the device is excited a 2-D or 3-D force-field can be generated, positioning the cells in lines or points respectively. Furthermore, it is possible to subsequently displace the cells with micrometer accuracy. This has been demonstrated using HL60 and MCF10A cells, and can be achieved without causing damage to the cells. Copyright © 2005 Wiley Periodicals, Inc. [source] | ||||||||||