Examination of the role of peptidylarginine deiminase 2 (PAD2) in gene expression in MCF-7 breast cancer cells
Ontology highlight
ABSTRACT: To investigate the potential role of peptidylarginine deiminase 2 (PAD2) in gene expression, we created stable shRNA scrambled control and PAD2 knockdown MCF-7 breast cancer cell lines. After validating the specific knockdown of PAD2 at the mRNA and protein level, we utilized an Agilent microarray platform to compare the gene expression profile of the two cell lines to generate a candidate list of genes regulated by PAD2. Control and PAD2 knockdown cells were created by stably transfecting shRNA constructs into MCF-7 cells. Stable cells were selected using puromycin and knockdown validate at the mRNA and protein level. Microarray data represents 4 independent biological replicates contain control and PAD2 knockdown samples.
Project description:To investigate the potential role of peptidylarginine deiminase 2 (PAD2) in gene expression, we created stable shRNA scrambled control and PAD2 knockdown MCF-7 breast cancer cell lines. After validating the specific knockdown of PAD2 at the mRNA and protein level, we utilized an Agilent microarray platform to compare the gene expression profile of the two cell lines to generate a candidate list of genes regulated by PAD2.
Project description:To investigate the potential role of peptidylarginine deiminase 2 (PAD2) in gene expression, we created stable shRNA scrambled control and PAD2 knockdown MCF-7 breast cancer cell lines. After validating the specific knockdown of PAD2 at the mRNA and protein level, we utilized an Agilent microarray platform to compare the gene expression profile of the two cell lines to generate a candidate list of genes regulated by PAD2. Control and PAD2 knockdown cells were created by stably transfecting shRNA constructs into MCF-7 cells. Stable cells were selected using puromycin and knockdown validate at the mRNA and protein level. Microarray data represents 4 independent biological replicates contain control and PAD2 knockdown samples.
Project description:Breast cancer (BC) is a serious and widespread disease for which different treatments have been developed. In addition to the classic therapies, the treatment with retinoic acid (RA) is still being clinically investigated. RA reduces cancer cells proliferation and migration, but its molecular mechanism of action is not clear. In tumor development, autophagy promotes cancer cell survival and prevents apoptosis. Small heat shock protein B8 (HSPB8) acts together with its co-chaperone BCL-2 associated athanogene 3 (BAG3) stimulating BC proliferation and migration. We analyzed whether direct correlations exist between RA and HSPB8 or BAG3 and how this may play a role in BC. We measured HSPB8 and BAG3 gene expression in MCF-7 BC cells and we analyzed the potential correlation between the antiproliferative and antimigratory effect of RA with the expression level of HSPB8. We found that in MCF-7 cells RA reduces both HSPB8 and BAG3 gene expression and it alters the mitotic spindle organization. Notably, the effects of RA on HSPB8 levels are exerted at both transcriptional and translational levels. RA effects are possibly mediated by miR-574-5p that targets the HSPB8 transcript. Our results suggest that therapeutic doses of RA can efficiently counteract the adverse effects of HSPB8 in BC progression.
Project description:BACKGROUND:Functional erythropoietin (EPO) signaling is not specific only to erythroid lineages and has been confirmed in several solid tumors, including breast. Three different isoforms of erythropoietin receptor (EPOR) have been reported, the soluble (EPOR-S) and truncated (EPOR-T) forms acting antagonistically to the functional EPOR. In this study, we investigated the effect of human recombinant erythropoietin (rHuEPO) on cell proliferation, early gene response and the expression of EPOR isoforms in the MCF-7 breast cancer cell line. MATERIALS AND METHODS:The MCF-7 cells were cultured with or without rHuEPO for 72 h or 10 weeks and assessed for their growth characteristics, expression of early response genes and different EPOR isoforms. The expression profile of EPOR and EPOR-T was determined in a range of breast cancer cell lines and compared with their invasive properties. RESULTS:MCF-7 cell proliferation after rHuEPO treatment was dependent on the time of treatment and the concentration used. High rHuEPO concentrations (40 U/ml) stimulated cell proliferation independently of a preceding long-term exposure of MCF-7 cells to rHuEPO, while lower concentrations increased MCF-7 proliferation only after 10 weeks of treatment. Gene expression analysis showed activation of EGR1 and FOS, confirming the functionality of EPOR. rHuEPO treatment also slightly increased the expression of the functional EPOR isoform, which, however, persisted throughout the 10 weeks of treatment. The expression levels of EPOR-T were not influenced. There were no correlations between EPOR expression and the invasiveness of MCF-7, MDA-MB-231, Hs578T, Hs578Bst, SKBR3, T-47D and MCF-10A cell lines. CONCLUSIONS:rHuEPO modulates MCF-7 cell proliferation in time- and concentration-dependent manner. We confirmed EGR1, FOS and EPOR as transcription targets of the EPO-EPOR signaling loop, but could not correlate the expression of different EPOR isoforms with the invasiveness of breast cancer cell lines.
Project description:Select changes in microRNA (miRNA) expression correlate with estrogen receptor alpha (ER alpha) expression in breast tumors. miR-21 is higher in ER alpha positive than negative tumors, but no one has examined how estradiol (E(2)) regulates miR-21 in breast cancer cells. Here we report that E(2) inhibits miR-21 expression in MCF-7 human breast cancer cells. The E(2)-induced reduction in miR-21 was inhibited by 4-hydroxytamoxifen (4-OHT), ICI 182 780 (Faslodex), and siRNA ER alpha indicating that the suppression is ER alpha-mediated. ER alpha and ER beta agonists PPT and DPN inhibited and 4-OHT increased miR-21 expression. E(2) increased luciferase activity from reporters containing the miR-21 recognition elements from the 3'-UTRs of miR-21 target genes, corroborating that E(2) represses miR-21 expression resulting in a loss of target gene suppression. The E(2)-mediated decrease in miR-21 correlated with increased protein expression of endogenous miR-21-targets Pdcd4, PTEN and Bcl-2. siRNA knockdown of ER alpha blocked the E(2)-induced increase in Pdcd4, PTEN and Bcl-2. Transfection of MCF-7 cells with antisense (AS) to miR-21 mimicked the E(2)-induced increase in Pdcd4, PTEN and Bcl-2. These results are the first to demonstrate that E(2) represses the expression of an oncogenic miRNA, miR-21, by activating estrogen receptor in MCF-7 cells.
Project description:The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, contributes to carcinogenesis through its role in the regulation of cytochrome P450 1 (CYP1)-catalyzed metabolism of carcinogens. Here, we investigated genetic and epigenetic mechanisms that affect AhR expression. Analyses of the human AHR proximal promoter in MCF-7 human breast cancer cells using luciferase assays and electrophoretic mobility shift assays revealed multiple specificity protein (Sp) 1 binding sequences that are transcriptional activators in vitro. The regulation of AhR expression was evaluated in long-term estrogen exposed (LTEE) MCF-7 cells, which showed increased AhR expression, enhanced CYP1 inducibility, and increased capacity to form DNA adducts when exposed to the dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine. The increased AhR expression in LTEE cells was found not to result from increased mRNA stability, differential RNA processing, or decreased DNA methylation. Analysis of the AHR proximal promoter region using chromatin immunoprecipitation confirmed that enhanced expression of AhR in LTEE cells involves changes in histone modifications, notably decreased trimethylation of histone 3, lysine 27. Upon further examination of the GC-rich Sp1-binding region, we confirmed that it contains a polymorphic (GGGGC)(n) repeat. In a population of newborns from New York State, the allele frequency of (GGGGC)(n) was n = 4 > 5 ? 6, 2. Circular dichroism spectroscopy revealed the ability of sequences of this GC-rich region to form guanine-quadruplex structures in vitro. These studies revealed multiple levels at which AhR expression may be controlled, and offer additional insights into mechanisms regulating AhR expression that can ultimately impact carcinogenesis.
Project description:Estrogens are critical mediators of breast tumorigenesis. This occurs via the action of estrogens on the estrogen receptor (ER), which regulates the transcriptome of breast cancer cells. Despite the long history of the search for estrogen-regulated genes in breast cancer, knowledge of the E2-regulated transcriptome and its effects is incomplete. We used Affymetrix GeneChips to profile the effects of estradiol on the expression of genes in EFF-3, EFM-19 and MCF-7 cells. In addition to many well-characterized estrogen-regulated genes, this identified a novel group of genes that have roles in vesicle trafficking, including exocytosis. Recent evidence in the literature supports a role for vesicle trafficking in tumorigenesis. We focused on five genes (SYTL5, RAB27B, SNX24, GALNT4 and SLC12A2/NKCC1/BSC2) and confirmed their estrogen-regulation using quantitative real-time PCR (qPCR). qPCR also demonstrated that these five genes were expressed in invasive breast carcinoma tissue. Immunohistochemistry showed expression of SYTL5 in cells of normal breast ductal epithelium, ductal carcinoma in-situ (DCIS) and invasive breast carcinoma. The results suggest that a significant effect of estrogens is to regulate the expression of genes that affect diverse aspects of vesicle trafficking including exocytosis.
Project description:Vascular endothelial growth factor (VEGF)165 is one of the most abundant and potent angiogenic factors in both physiological and pathological conditions. However, the function and mechanism of VEGF165 in tumors and their environment remain to be elucidated. In the present study, a lentivirus vector (LV) that contained the VEGF165-enhanced green fluorescent protein (EGFP) fusion gene was constructed and transfected into the human breast cancer cell line MCF-7. Following transfection, the expression of VEGF165 in MCF-7 cells was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Further cellular localization of VEGF165 was observed through fluorescence microscopy. The titer of the recombinant lentivirus was 5.44×107 TU/ml in the LV-VEGF165-EGFP group and 5.00×108 TU/ml in the LV-EGFP negative control group. RT-qPCR and western blotting demonstrated that the expression of VEGF165 was significantly increased in the LV-VEGF165-EGFP group compared with the control group. The present study lays the foundation for in vitro and in vivo studies on tumor cell derived-VEGF165. Furthermore, the present fusion gene expression vector may provide a potential approach for gene therapy treatment of cancer and other diseases that require regulation of angiogenesis.
Project description:Elevated expression of chemokine receptors in tumors has been reported in many instances and is related to a number of survival advantages for tumor cells including abnormal activation of prosurvival intracellular pathways. In this work we demonstrated an inverse correlation between expression levels of p53 tumor suppressor and CXCR5 chemokine receptor in MCF-7 human breast cancer cell line. Lentiviral transduction of MCF-7 cells with p53 shRNA led to elevated CXCR5 at both mRNA and protein levels. Functional activity of CXCR5 in p53-knockdown MCF-7 cells was also increased as shown by activation of target gene expression and chemotaxis in response to B-lymphocyte chemoattractant CXCL13. Using deletion analysis and site-directed mutagenesis of the cxcr5 gene promoter and enhancer elements, we demonstrated that p53 appears to act upon cxcr5 promoter indirectly, by repressing the activity of NFκB transcription factors. Using chromatin immunoprecipitation and reporter gene analysis, we further demonstrated that p65/RelA was able to bind the cxcr5 promoter in p53-dependent manner and to directly transactivate it when overexpressed. Through the described mechanism, elevated CXCR5 expression may contribute to abnormal cell survival and migration in breast tumors that lack functional p53.
Project description:Topotecan is a clinically active anticancer agent for the management of various human tumors. While the principal mechanism of tumor cell killing by topotecan is due to its interactions with topoisomerase I and formation of DNA double-strand breaks, recent studies suggest that mechanisms involving generation of reactive free radicals and induction of oxidative stress may play a significant role in topotecan-dependent tumor cell death. We have shown that topotecan generates a topotecan radical following one-electron oxidation by a peroxidase-hydrogen peroxide system which reacts with reduced glutathione and cysteine, forming the glutathiyl and cysteinyl radicals, respectively. While little is known how these events are involved in topotecan-induced tumor cell death, we have now examined the effects of topotecan short (1 h) and long (24 h) exposure on global gene expression patterns using gene expression microarray analysis in human breast MCF-7 cancer cells, a wild-type p53 containing cell line. We show here that topotecan treatment significantly down-regulated estrogen receptor alpha (ERα/ESR1) and antiapoptotic BCL2 genes in addition to many other p53-regulated genes. Furthermore, 8-oxoguanine DNA glycosylase (OGG1), ferredoxin reductase (FDXR), methionine sulfoxide reductase (MSR), glutathione peroxidases (GPx), and glutathione reductase (GSR) genes were also differentially expressed by topotecan treatment. The differential expression of these genes was observed in a wild-type p53-containing breast ZR-75-1 tumor cell line following topotecan treatment. The involvement of reactive oxygen free radical sensor genes, the oxidative DNA damage (OGG1) repair gene and induction of pro-apoptotic genes suggest that reactive free radical species play a role in topotecan-induced tumor cell death.