scholarly journals KRAB domain of ZFP568 disrupts TRIM28-mediated abnormal interactions in cancer cells

NAR Cancer ◽  
2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Janani Kumar ◽  
Gundeep Kaur ◽  
Ren Ren ◽  
Yue Lu ◽  
Kevin Lin ◽  
...  
Keyword(s):  
Dna Binding ◽  
Transposable Elements ◽  
Cancer Cells ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Mcf7 Cells ◽  
Interaction Domain ◽  
Protein Levels ◽  
Krab Domain ◽  
Regulatory Feedback Loop

Abstract Interactions of KRAB (Krüppel-associated box)-associated protein KAP1 [also known as TRIM28 (tripartite motif containing protein 28)] with DNA-binding KRAB zinc finger (KRAB-ZF) proteins silence many transposable elements during embryogenesis. However, in some cancers, TRIM28 is upregulated and interacts with different partners, many of which are transcription regulators such as EZH2 in MCF7 cells, to form abnormal repressive or activating complexes that lead to misregulation of genes. We ask whether a KRAB domain—the TRIM28 interaction domain present in native binding partners of TRIM28 that mediate repression of transposable elements—could be used as a tool molecule to disrupt aberrant TRIM28 complexes. Expression of KRAB domain containing fragments from a KRAB-ZF protein (ZFP568) in MCF7 cells, without the DNA-binding zinc fingers, inhibited TRIM28–EZH2 interactions and caused degradation of both TRIM28 and EZH2 proteins as well as other components of the EZH2-associated polycomb repressor 2 complex. In consequence, the product of EZH2 enzymatic activity, trimethylation of histone H3 lysine 27 level, was significantly reduced. The expression of a synthetic KRAB domain significantly inhibits the growth of breast cancer cells (MCF7) but has no effect on normal (immortalized) human mammary epithelial cells (MCF10a). Further, we found that TRIM28 is a positive regulator of TRIM24 protein levels, as observed previously in prostate cancer cells, and expression of the KRAB domain also lowered TRIM24 protein. Importantly, reduction of TRIM24 levels, by treatment with either the KRAB domain or a small-molecule degrader targeted to TRIM24, is accompanied by an elevated level of tumor suppressor p53. Taken together, this study reveals a novel mechanism for a TRIM28-associated protein stability network and establishes TRIM28 as a potential therapeutic target in cancers where TRIM28 is elevated. Finally, we discuss a potential mechanism of KRAB-ZF gene expression controlled by a regulatory feedback loop of TRIM28–KRAB.

scholarly journals Arsenic hexoxide has differential effects on cell proliferation and genome-wide gene expression in human primary mammary epithelial and MCF7 cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Donguk Kim ◽  
Na Yeon Park ◽  
Keunsoo Kang ◽  
Stuart K. Calderwood ◽  
Dong-Hyung Cho ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Mammary Epithelial ◽  
Mcf7 Cells ◽  
Differential Effects ◽  
Cycle Arrest ◽  
Genome Wide ◽  
Human Mammary Epithelial ◽  
Genome Wide Gene Expression

AbstractArsenic is reportedly a biphasic inorganic compound for its toxicity and anticancer effects in humans. Recent studies have shown that certain arsenic compounds including arsenic hexoxide (AS4O6; hereafter, AS6) induce programmed cell death and cell cycle arrest in human cancer cells and murine cancer models. However, the mechanisms by which AS6 suppresses cancer cells are incompletely understood. In this study, we report the mechanisms of AS6 through transcriptome analyses. In particular, the cytotoxicity and global gene expression regulation by AS6 were compared in human normal and cancer breast epithelial cells. Using RNA-sequencing and bioinformatics analyses, differentially expressed genes in significantly affected biological pathways in these cell types were validated by real-time quantitative polymerase chain reaction and immunoblotting assays. Our data show markedly differential effects of AS6 on cytotoxicity and gene expression in human mammary epithelial normal cells (HUMEC) and Michigan Cancer Foundation 7 (MCF7), a human mammary epithelial cancer cell line. AS6 selectively arrests cell growth and induces cell death in MCF7 cells without affecting the growth of HUMEC in a dose-dependent manner. AS6 alters the transcription of a large number of genes in MCF7 cells, but much fewer genes in HUMEC. Importantly, we found that the cell proliferation, cell cycle, and DNA repair pathways are significantly suppressed whereas cellular stress response and apoptotic pathways increase in AS6-treated MCF7 cells. Together, we provide the first evidence of differential effects of AS6 on normal and cancerous breast epithelial cells, suggesting that AS6 at moderate concentrations induces cell cycle arrest and apoptosis through modulating genome-wide gene expression, leading to compromised DNA repair and increased genome instability selectively in human breast cancer cells.

Interaction of two sequence-specific single-stranded DNA-binding proteins with an essential region of the beta-casein gene promoter is regulated by lactogenic hormones

1993 ◽  
Vol 13 (12) ◽  
pp. 7303-7310
Author(s):  
S Altiok ◽  
B Groner
Keyword(s):  
Dna Binding ◽  
Binding Proteins ◽  
Mammary Epithelial Cells ◽  
Dna Binding Proteins ◽  
Binding Activity ◽  
Mammary Epithelial ◽  
Nuclear Proteins ◽  
Single Stranded Dna ◽  
Dna Binding Activity ◽  
Beta Casein

Transcription of the beta-casein gene in mammary epithelial cells is regulated by the lactogenic hormones insulin, glucocorticoids, and prolactin. The DNA sequence elements in the promoter which confer the action of the hormones on the transcriptional machinery and the nuclear proteins binding to this region have been investigated. We found that 221 nucleotides of promoter sequence 5' of the RNA start site are sufficient to mediate the induction of a chloramphenicol acetyltransferase reporter gene in transfected HC11 mammary epithelial cells. Deletion of 5' sequences to position -183 results in a construct with enhanced basal activity which still retains inducibility. A -170 beta-casein promoter-chloramphenicol acetyltransferase construct has very low transcriptional activity, which indicates the presence of a negative regulatory in the region between -221 and -183 and a positive regulatory element between -183 and -170. Band shift analysis showed that the promoter region between -194 and -163 specifically binds two nuclear proteins. The proteins are sequence-specific, single-stranded DNA-binding proteins which exclusively recognize the upper DNA strand and most likely play a repressing role in transcription. DNA binding activity of these nuclear proteins was observed only in nuclear extracts from mammary glands of mice in late pregnancy and postlactation, not during lactation. Hormonal control of the DNA binding activity of these proteins was also observed in the mammary epithelial cell line HC11. Mixing experiments showed that extracts from mammary tissue of lactating mice and from lactogenic hormone-treated HC11 cells contain an activity which can suppress the DNA binding of the single-stranded DNA-binding proteins.2+ identical specificity to the single-stranded DNA.

scholarly journals ZFHX3 Promotes the Proliferation and Tumor Growth of ER-Positive Breast Cancer Cells Likely by Enhancing Stem-Like Features and MYC and TBX3 Transcription

Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3415
Author(s):  
Ge Dong ◽  
Gui Ma ◽  
Rui Wu ◽  
Jinming Liu ◽  
Mingcheng Liu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Growth ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Molecular Mechanisms ◽  
Mammary Epithelial Cells ◽  
Progesterone Receptors ◽  
Mammary Epithelial ◽  
Luciferase Reporter ◽  
Mammosphere Formation

Breast cancer is a common malignancy, but the understanding of its cellular and molecular mechanisms is limited. ZFHX3, a transcription factor with many homeodomains and zinc fingers, suppresses prostatic carcinogenesis but promotes tumor growth of liver cancer cells. ZFHX3 regulates mammary epithelial cells’ proliferation and differentiation by interacting with estrogen and progesterone receptors, potent breast cancer regulators. However, whether ZFHX3 plays a role in breast carcinogenesis is unknown. Here, we found that ZFHX3 promoted the proliferation and tumor growth of breast cancer cells in culture and nude mice; and higher expression of ZFHX3 in human breast cancer specimens was associated with poorer prognosis. The knockdown of ZFHX3 in ZFHX3-high MCF-7 cells decreased, and ZFHX3 overexpression in ZFHX3-low T-47D cells increased the proportion of breast cancer stem cells (BCSCs) defined by mammosphere formation and the expression of CD44, CD24, and/or aldehyde dehydrogenase 1. Among several transcription factors that have been implicated in BCSCs, MYC and TBX3 were transcriptionally activated by ZFHX3 via promoter binding, as demonstrated by luciferase-reporter and ChIP assays. These findings suggest that ZFHX3 promotes breast cancer cells’ proliferation and tumor growth likely by enhancing BCSC features and upregulating MYC, TBX3, and others.

scholarly journals Screening antiproliferative drug for breast cancer from bisbenzylisoquinoline alkaloid tetrandrine and fangchinoline derivatives by targeting BLM helicase

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Wangming Zhang ◽  
Shuang Yang ◽  
Jinhe Liu ◽  
Linchun Bao ◽  
He Lu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Binding ◽  
Small Molecules ◽  
Cancer Cells ◽  
Small Molecule ◽  
Breast Cancer Cells ◽  
Dna Unwinding ◽  
Protein Levels ◽  
Blm Helicase ◽  
Bisbenzylisoquinoline Alkaloids

Abstract Background The high expression of BLM (Bloom syndrome) helicase in tumors involves its strong association with cell expansion. Bisbenzylisoquinoline alkaloids own an antitumor property and have developed as candidates for anticancer drugs. This paper aimed to screen potential antiproliferative small molecules from 12 small molecules (the derivatives of bisbenzylisoquinoline alkaloids tetrandrine and fangchinoline) by targeting BLM642–1290 helicase. Then we explore the inhibitory mechanism of those small molecules on proliferation of MDA-MB-435 breast cancer cells. Methods Fluorescence polarization technique was used to screen small molecules which inhibited the DNA binding and unwinding of BLM642–1290 helicase. The effects of positive small molecules on the ATPase and conformation of BLM642–1290 helicase were studied by the malachite green-phosphate ammonium molybdate colorimetry and ultraviolet spectral scanning, respectively. The effects of positive small molecules on growth of MDA-MB-435 cells were studied by MTT method, colony formation and cell counting method. The mRNA and protein levels of BLM helicase in the MDA-MB-435 cells after positive small molecule treatments were examined by RT-PCR and ELISA, respectively. Results The compound HJNO (a tetrandrine derivative) was screened out which inhibited the DNA binding, unwinding and ATPase of BLM642–1290 helicase. That HJNO could bind BLM642–1290helicase to change its conformationcontribute to inhibiting the DNA binding, ATPase and DNA unwinding of BLM642–1290 helicase. In addition, HJNO showed its inhibiting the growth of MDA-MB-435 cells. The values of IC50 after drug treatments for 24 h, 48 h and 72 h were 19.9 μmol/L, 4.1 μmol/L and 10.9 μmol/L, respectively. The mRNA and protein levels of BLM helicase in MDA-MB-435 cells increased after HJNO treatment. Those showed a significant difference (P < 0.05) compared with negative control when the concentrations of HJNO were 5 μmol/L and 10 μmol/L, which might contribute to HJNO inhibiting the DNA binding, ATPase and DNA unwinding of BLM helicase. Conclusion The small molecule HJNO was screened out by targeting BLM642–1290 helicase. And it showed an inhibition on MDA-MB-435 breast cancer cells expansion.

scholarly journals Dual Epigenetic Regulation of ERα36 Expression in Breast Cancer Cells

2019 ◽  
Vol 20 (11) ◽  
pp. 2637 ◽  
Author(s):  
Charlène Thiebaut ◽  
Amand Chesnel ◽  
Jean-Louis Merlin ◽  
Maelle Chesnel ◽  
Agnès Leroux ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Mammary Epithelial Cells ◽  
Methylation Status ◽  
Acquired Resistance ◽  
Good Prognosis ◽  
Mammary Epithelial ◽  
Endogenous Expression ◽  
Epigenetic Modulation

Breast cancer remains the major cause of cancer-induced morbidity and mortality in women. Among the different molecular subtypes, luminal tumors yet considered of good prognosis often develop acquired resistance to endocrine therapy. Recently, misregulation of ERα36 was reported to play a crucial role in this process. High expression of this ERα isoform was associated to preneoplastic phenotype in mammary epithelial cells, disease progression, and enhanced resistance to therapeutic agents in breast tumors. In this study, we identified two mechanisms that could together contribute to ERα36 expression regulation. We first focused on hsa-miR-136-5p, an ERα36 3’UTR-targeting microRNA, the expression of which inversely correlated to the ERα36 one in breast cancer cells. Transfection of hsa-miR136-5p mimic in MCF-7 cells resulted in downregulation of ERα36. Moreover, the demethylating agent decitabine was able to stimulate hsa-miR-136-5p endogenous expression, thus indirectly decreasing ERα36 expression and counteracting tamoxifen-dependent stimulation. The methylation status of ERα36 promoter also directly modulated its expression level, as demonstrated after decitabine treatment of breast cancer cell and confirmed in a set of tumor samples. Taken together, these results open the way to a direct and an indirect ERα36 epigenetic modulation by decitabine as a promising clinical strategy to counteract acquired resistance to treatment and prevent relapse.

Breast Cancer Diagnosed by MRI Using Mesoporous TiO2-Coated (Fe3O4) Nanoparticles

2020 ◽  
Vol 20 (10) ◽  
pp. 6561-6567 ◽  
Author(s):  
Bo Zheng ◽  
Minghua Xue ◽  
Xinyi Zhang ◽  
Ning Tian ◽  
Dongmei Wang
Keyword(s):  
Breast Cancer ◽  
Glucose Metabolism ◽  
Cancer Cells ◽  
Mammary Epithelial Cells ◽  
Glucose Consumption ◽  
Mammary Epithelial ◽  
Blue Staining ◽  
Human Mammary Epithelial ◽  
Significant Uptake ◽  
Mcf 7

Objective: This study aimed to determine the effects of dimer captosuccinic acid-coated Fe3O4 (super paramagnetic) nanoparticles (NP) on 2-deoxy-d-glucose in targeted cancer cells with high rates of glucose metabolism. Methods: We prepared Fe3O4@DMSA NP and 2-DG-conjugated Fe3O4@DMSA NP, γ-FE, O, and @DMSA-DG NP. Glucose consumption in MDA-MB-231 and MCF-7 breast cancer cells was determined using γ-Fe2O3@DMSA NP or Fe3O4@DMSA-DG NP, and absorption was tested using Prussian blue staining, ultraviolet colorimetry, and magnetic resonance imaging. Results: Glucose consumption was the highest in MDA-MB-231, and the lowest in human mammary epithelial cells (HMEPiC). The significant uptake of Fe2O3@DMSA-DG NP by MDA-MB-231 and MCF-7 cells within two hours was inhibited by glucose. The uptake of Fe3O4@DMSA-DG NP was significantly higher in MDA-MB-231 than in MCF-7 cells, whereas Fe3O4@DMSA NP was not obviously uptaken by either cell line. Absorption was also not evident in HMEPiC incubated with Fe3O4@DMSA-DG NP and Fe3O4@DMSA NP. Conclusions: The tumor targeting efficacy of 2-DG coated Fe3O4@DMSA NP was improved over Fe3O4,@DMSA NP in cancer cells with high rates of glucose metabolism.

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