Identification of Cellular Binding Sites for a Novel Human Anti-Breast Cancer Peptide

2003 ◽  
Author(s):  
Lori A. DeFreest ◽  
James A. Bennett
Keyword(s):  
Breast Cancer ◽  
Binding Sites

scholarly journals AKT Alters Genome-Wide Estrogen Receptor α Binding and Impacts Estrogen Signaling in Breast Cancer

2008 ◽  
Vol 28 (24) ◽  
pp. 7487-7503 ◽  
Author(s):  
Poornima Bhat-Nakshatri ◽  
Guohua Wang ◽  
Hitesh Appaiah ◽  
Nikhil Luktuke ◽  
Jason S. Carroll ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Binding Sites ◽  
Transforming Growth Factor ◽  
Cell Types ◽  
Estrogen Receptor Α ◽  
Estrogen Signaling ◽  
Primary Tumors ◽  
Genome Wide ◽  
Extracellular Signal

ABSTRACT Estrogen regulates several biological processes through estrogen receptor α (ERα) and ERβ. ERα-estrogen signaling is additionally controlled by extracellular signal activated kinases such as AKT. In this study, we analyzed the effect of AKT on genome-wide ERα binding in MCF-7 breast cancer cells. Parental and AKT-overexpressing cells displayed 4,349 and 4,359 ERα binding sites, respectively, with ∼60% overlap. In both cell types, ∼40% of estrogen-regulated genes associate with ERα binding sites; a similar percentage of estrogen-regulated genes are differentially expressed in two cell types. Based on pathway analysis, these differentially estrogen-regulated genes are linked to transforming growth factor β (TGF-β), NF-κB, and E2F pathways. Consistent with this, the two cell types responded differently to TGF-β treatment: parental cells, but not AKT-overexpressing cells, required estrogen to overcome growth inhibition. Combining the ERα DNA-binding pattern with gene expression data from primary tumors revealed specific effects of AKT on ERα binding and estrogen-regulated expression of genes that define prognostic subgroups and tamoxifen sensitivity of ERα-positive breast cancer. These results suggest a unique role of AKT in modulating estrogen signaling in ERα-positive breast cancers and highlights how extracellular signal activated kinases can change the landscape of transcription factor binding to the genome.

scholarly journals LncRNA SNHG6/miR-125b-5p/BMPR1B Axis: A New Therapeutic Target for Triple-Negative Breast Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Yufei Lv ◽  
Xiaohong Lv ◽  
Huike Yang ◽  
Xiuying Qi ◽  
Xiangchen Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Binding Sites ◽  
Luciferase Reporter ◽  
Breast Cancer Cell Lines ◽  
Breast Epithelial Cell ◽  
Ki 67 ◽  
Cancer Data ◽  
Tnbc Cell ◽  
Direct Binding

BackgroundTriple-negative breast cancer (TNBC) is a significant cause of patient morbidity. The exactly pathobiological features of this condition has yet to be completely elucidated.MethodsBreast cancer data obtained from The Cancer Genome Atlas (TCGA) database were evaluated for lncRNA SNHG6 expression. Normal human breast epithelial cell line (MCF-10A) and other breast cancer cell lines (BT-549, MDA-MB-231, Hs 578t, ZR-75-30, SK-BR-3, MCF-7) were also assessed for lncRNA SNHG6 expressions. Cellular proliferative ability was evaluated with colony formation and CCK-8 assays. The ability of cells to migrate was scrutinized with the wound healing and Boyden chamber cell migration assays. qRT-PCR enabled for detection of lncRNA SNHG6, miR-125b-5p and BMPR1B mRNA expressions. Protein BMPR1B expressions were further assessed using Western Blotting. Direct binding sites between transcripts were determined using dual-luciferase reporter assays. We also constructed a xenograft mouse model to further dissect the vivo implications of lncRNA SNHG6. Ki-67 and c-Caspase-3 expressions were detected using immunohistochemistry staining.ResultsBreast cancer cell lines demonstrated higher lncRNA SNHG6 expressions, particularly TNBC cell lines, in contrast to normal breast epithelial cell lines. This finding coincided with those noted on analysis of TCGA breast cancer data. lncRNA SNHG6 knockdown inhibited TNBC cell proliferation, migration, while promoted cell apoptosis. Furthermore, suppressed lncRNA SNHG6 expressions resulted in lower tumor weights and volumes in a xenograft mouse model, as evidenced by Ki-67 and c-Caspase-3 expression profiles in tumor tissues. miR-125b-5p and lncRNA SNHG6/BMPR1B both possessed direct binding sites for each other which was validated utilizing a dual-luciferase reporter assay. Decreasing lncRNA SNHG6 expression in TNBC cells upregulated miR-125b-5p expression. Another side, inhibiting miR-125b-5p upregulated BMPR1B expression in these cells. Moreover, knocking down lncRNA SNHG6 downregulated BMPR1B expression in TNBC cells, and the finding was rescued in cells which were exposed to miR-125b-5p inhibitor. Downregulating miR-125b-5p mitigated the effect of suppressing lncRNA SNHG6 on TNBC cell proliferation, migration, and apoptosis.ConclusionDownregulation of lncRNA SNHG6 could inhibit TNBC cell proliferative, migratory capabilities and promote apoptosis capability, likely through modulation of the miR-125b-5p/BMPR1B axis. This axis may be targeted in formulating new therapies for TNBC.

scholarly journals Whole-cell uptake and nuclear localization of 1,25-dihydroxycholecalciferol by breast cancer cells (T47 D) in culture

1981 ◽  
Vol 200 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Elizabeth Sher ◽  
John A. Eisman ◽  
Jane M. Moseley ◽  
T. John Martin
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Binding Sites ◽  
Breast Cancer Cells ◽  
Nuclear Translocation ◽  
Vitamin D Metabolites ◽  
Intact Cells ◽  
Cells In Culture

Specific high-affinity receptors for 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] have been described recently in broken-cell preparations of several cultured human breast cancer cell lines including the T47 D line. It was necessary to determine whether intact breast cancer cells in culture would bind 1,25-(OH)2D3 specifically and whether the next step in the proposed scheme of action, i.e. nuclear translocation, occurred. The following results were obtained. (1) Specific uptake of 1,25-(OH)2D3 by T47 D cells occurs in intact cells in culture. (2) The rate of uptake is proportional to medium 1,25-(OH)2D3 concentration but is slow compared with that of other steroid hormones, e.g., oestradiol, under identical conditions. Even at 0.5nm-1,25-(OH)2D3 in the medium, at least 4h are required to reach maximum compared with less than 1h for oestradiol binding. (3) Estimation of binding characteristics by Scatchard analysis indicates a single class of binding sites with Kd of 68pm and 11800 binding sites/cell, which are similar results to those obtained with broken-cell preparations. (4) Inclusion of various vitamin D metabolites in the incubation medium decreased specific binding of 1,25-(OH)2D3 by the intact cells in a manner identical with their effects in the broken-cell preparation and with potencies similar to their potency on Ca2+ transport and bone resorption in vivo. Order of potency was 1,25-(OH)2D3>(24R)-1,24,25-trihydroxycholecalciferol »25-hydroxycholecalciferol>(25R)-24,25-dihydroxycholecalciferol »(25R)-25,26-dihydroxycholecalciferol. (5) In the 1,25-(OH)2D3-depleted state, 80% of the 1,25(OH)2D3 receptor is found in the cytosol fraction of the cells even when the subcellular fractionation is performed under low-salt conditions. By contrast after incubation with [3H]1,25-(OH)2D3, 59% of the specific 1,25-(OH)2D3 binding is found in the partially purified nuclei fraction. These data indicate that nuclear translocation of the receptor–hormone complex takes place in the intact T47 D cell. The results also support the hypothesis that the 1,25-(OH)2D3 receptor is functional in this cultured breast cancer cell line, which may provide a useful model for further study of the early biochemical events in 1,25-(OH)2D3 action.

scholarly journals An H3K4me3 reader, BAP18 as an adaptor of COMPASS-like core subunits co-activates ERα action and associates with the sensitivity of antiestrogen in breast cancer

2020 ◽  
Vol 48 (19) ◽  
pp. 10768-10784
Author(s):  
Ge Sun ◽  
Chunyu Wang ◽  
Shengli Wang ◽  
Hongmiao Sun ◽  
Kai Zeng ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Progression ◽  
Binding Sites ◽  
Estrogen Receptor Alpha ◽  
Target Genes ◽  
Regulatory Element ◽  
Therapy Resistance ◽  
Ctcf Binding ◽  
Promoter Regions ◽  
Positive Breast Cancer

Abstract Estrogen receptor alpha (ERα) signaling pathway is essential for ERα-positive breast cancer progression and endocrine therapy resistance. Bromodomain PHD Finger Transcription Factor (BPTF) associated protein of 18kDa (BAP18) has been recognized as a crucial H3K4me3 reader. However, the whole genomic occupation of BAP18 and its biological function in breast cancer is still elusive. Here, we found that higher expression of BAP18 in ERα-positive breast cancer is positively correlated with poor prognosis. ChIP-seq analysis further demonstrated that the half estrogen response elements (EREs) and the CCCTC binding factor (CTCF) binding sites are the significant enrichment sites found in estrogen-induced BAP18 binding sites. Also, we provide the evidence to demonstrate that BAP18 as a novel co-activator of ERα is required for the recruitment of COMPASS-like core subunits to the cis-regulatory element of ERα target genes in breast cancer cells. BAP18 is recruited to the promoter regions of estrogen-induced genes, accompanied with the enrichment of the lysine 4-trimethylated histone H3 tail (H3K4me3) in the presence of E2. Furthermore, BAP18 promotes cell growth and associates the sensitivity of antiestrogen in ERα-positive breast cancer. Our data suggest that BAP18 facilitates the association between ERα and COMPASS-like core subunits, which might be an essential epigenetic therapeutic target for breast cancer.

Occupied and unoccupied type II estrogen binding sites in human breast cancer

1987 ◽  
Vol 26 (2) ◽  
pp. 219-226 ◽  
Author(s):  
M.T.P. Lopes ◽  
M.H. Liberato ◽  
A. Widman ◽  
M.M. Brentani
Keyword(s):  
Breast Cancer ◽  
Binding Sites ◽  
Human Breast Cancer ◽  
Type Ii ◽  
Human Breast ◽  
Estrogen Binding

scholarly journals Lectin-binding properties of human breast cancer cell lines and human milk with particular reference to Helix pomatia agglutinin.

1995 ◽  
Vol 43 (3) ◽  
pp. 275-281 ◽  
Author(s):  
U Schumacher ◽  
E Adam ◽  
S A Brooks ◽  
A J Leathem
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Binding Sites ◽  
Lectin Binding ◽  
Helix Pomatia ◽  
Breast Cancer Cell Lines ◽  
Human Breast ◽  
Membrane Glycoproteins ◽  
Tissue Sections ◽  
Helix Pomatia Agglutinin

Several studies have shown binding of a variety of lectins to breast cancer cells in tissue sections. In particular, binding of the lectin from the Roman snail, Helix pomatia agglutinin (HPA), to breast cancer cells is linked with a poor prognosis. The molecular basis for lectin binding to metastatic breast cancers is not known. To elucidate this in a model system, lectin-binding patterns of seven human breast cancer cell lines were investigated, their cell membranes were isolated, and HPA binding was assessed. In addition, the influence of fixation and processing on lectin-binding sites was also investigated. Binding of lectins to the tumor cells was very heterogeneous between and within the different cell lines and was influenced by fixation and processing. However, some cell lines showed HPA-binding sites both in vivo and in tissue sections. Analysis of the isolated cell membrane glycoproteins from these cell lines on Western blots revealed that HPA can bind to several membrane glycoproteins. In contrast, human milk shows only one major milk glycoprotein that is HPA-positive. Therefore, a switch in glycosylation appears to be taking place during the transformation to a metastatic phenotype.

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