scholarly journals Unravelling the RNA-Binding Properties of SAFB Proteins in Breast Cancer Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Elaine Hong ◽  
Andrew Best ◽  
Hannah Gautrey ◽  
Jas Chin ◽  
Anshuli Razdan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
High Throughput Sequencing ◽  
Rna Binding ◽  
Open Reading Frames ◽  
Rna Recognition Motif ◽  
Binding Properties ◽  
Intergenic Regions ◽  
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Scaffold attachment factor B1 (SAFB1) and SAFB2 proteins are oestrogen (ER) corepressors that bind to and modulate ER activity through chromatin remodelling or interaction with the basal transcription machinery. SAFB proteins also have an internal RNA-recognition motif but little is known about the RNA-binding properties of SAFB1 or SAFB2. We utilised crosslinking and immunoprecipitation (iCLIP) coupled with high-throughput sequencing to enable a transcriptome-wide mapping of SAFB1 protein-RNA interactions in breast cancer MCF-7 cells. Analysis of crosslinking frequency mapped to transcript regions revealed that SAFB1 binds to coding and noncoding RNAs (ncRNAs). The highest proportion of SAFB1 crosslink sites mapped to ncRNAs, followed by intergenic regions, open reading frames (ORFs), introns, and 3′ or 5′ untranslated regions (UTR). Furthermore, we reveal that SAFB1 binds directly to RNA and its binding is particularly enriched at purine-rich sequences not dissimilar to the RNA-binding motifs for SR proteins. Using RNAi, we also show, for the first time, that single depletion of either SAFB1 or SAFB2 leads to an increase in expression of the other SAFB protein in both MCF-7 and MDA-MD231 breast cancer cells.

Oncogenic p95HER2 regulates Na+–HCO3− cotransporter NBCn1 mRNA stability in breast cancer cells via 3′UTR-dependent processes*

2016 ◽  
Vol 473 (21) ◽  
pp. 4027-4044 ◽  
Author(s):  
Andrej Gorbatenko ◽  
Christina W. Olesen ◽  
Nathalie Loebl ◽  
Haraldur H. Sigurdsson ◽  
Carolina Bianchi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Rna Binding ◽  
Growth Factor Receptor ◽  
Luciferase Reporter ◽  
Central Position ◽  
Reporter Expression ◽  
General Role ◽  
Mcf 7

The Na+–HCO3– cotransporter NBCn1 (SLC4A7) is up-regulated in breast cancer, important for tumor growth, and a single nucleotide polymorphism (SNP), rs4973768, in its 3′ untranslated region (3′UTR) correlates with increased breast cancer risk. We previously demonstrated that NBCn1 expression and promoter activity are strongly increased in breast cancer cells expressing a constitutively active oncogenic human epidermal growth factor receptor 2 (HER2) (p95HER2). Here, we address the roles of p95HER2 in regulating NBCn1 expression via post-transcriptional mechanisms. p95HER2 expression in MCF-7 cells reduced the rate of NBCn1 mRNA degradation. The NBCn1 3′UTR down-regulated luciferase reporter expression in control cells, and this was reversed by p95HER2, suggesting that p95HER2 counteracts 3′UTR-mediated suppression of NBCn1 expression. Truncation analyses identified three NBCn1 3′UTR regions of regulatory importance. Mutation of putative miRNA-binding sites (miR-374a/b, miR-200b/c, miR-29a/b/c, miR-488) in these regions did not have significant impact on 3′UTR activity. The NBCn1 3′UTR interacted directly with the RNA-binding protein human antigen R (HuR), and HuR knockdown reduced NBCn1 expression. Conversely, ablation of a distal AU-rich element increased 3′UTR-driven reporter activity, suggesting complex regulatory roles of these sites. The cancer-associated SNP variant decreased reporter expression in T-47D breast cancer cells, yet not in MCF-7, MDA-MB-231 and SK-BR-3 cells, arguing against a general role in regulating NBCn1 expression. Finally, p95HER2 expression increased total and plasma membrane NBCn1 protein levels and decreased the rate of NBCn1 protein degradation. Collectively, this is the first work to demonstrate 3′UTR-mediated NBCn1 regulation, shows that p95HER2 regulates NBCn1 expression at multiple levels, and substantiates the central position of p95HER2–NBCn1 signaling in breast cancer.

scholarly journals OR09-06 HNRNPA2B1 Mediates Endocrine-Sensitivity and Alters PSAT1 in Breast Cancer Cells

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Carolyn M Klinge ◽  
Kellianne M Piell ◽  
Bran F Clem ◽  
Belinda J Petri
Keyword(s):  
Breast Cancer ◽  
Growth Inhibition ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Rna Binding ◽  
Cell Junction ◽  
Breast Cancer Patients ◽  
Mirna Regulation ◽  
Luminal A ◽  
Mcf 7

Abstract Higher expression of the RNA binding protein HNRNPA2B1 (Heterogeneous Nuclear Ribonucleoprotein A2/B1), a reader of the N(6)-methyladenosine (m6A) mark in transcribed RNA, is found in endocrine-resistant, estrogen receptor (ERα)+ LCC9 and LY2 breast cancer cells derived from MCF-7 endocrine-sensitive luminal A cells (1). HNRNPA2B1 interacts with DGCR8 in the DROSHA complex to promote processing of pri-miRNAs to pre-miRNAs. We identified HNRNPA2B1-regulated miRNAs by RNA seq and target pathways, including serine family amino acid metabolic processes, TGFβ signaling, response to estrogen, and cell junction by MetaCore enrichment pathway analysis (1). Stable 4.5-fold overexpression of HNRNPA2B1 in MCF-7 cells (MCF-7-A2B1 cells) results in ablation of growth inhibition by 4-hydroxytamoxifen (4-OHT) and fulvestrant. This was not due to loss or decrease of ERα; in fact, ERα was increased ~ 1.6-fold. Conversely, transient knockdown of HNRNPA2B1 expression in LCC9 and LY2 cells sensitized the cells to growth inhibition by 4-OHT and fulvestrant, without changing ESR1 expression. MCF-7-A2B1 cells showed increased migration, reduced E-cadherin and increased vimentin, suggestive of EMT; however, they exhibited reduced clonogenic survival. Follow-up on the identification of HNRNPA2B1-miRNA regulation of the serine pathway revealed higher expression of phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase (PSAT1) transcripts and proteins in LCC9, LY2, and MCF-7-A2B1 compared to MCF-7 cells. We identified two miRNAs, miR-424-5p and miR-145-5p downregulated in MCF-7-A2B1 cells that directly targeted the PSAT1 3’UTR in dual luciferase assays. Lower miR-424-5p and miR-145-5p in endocrine-resistant LCC9 and LY2 correlate with increased PSAT1 and higher PSAT1 is associated with reduced overall and metastasis-free survival in breast cancer patients. Overall, our data suggest a role for increased HNRNPA2B1 in tamoxifen-resistance. Reference: (1) Klinge CM, Piell KM, Tooley CS, Rouchka EC. HNRNPA2/B1 is upregulated in endocrine-resistant LCC9 breast cancer cells and alters the miRNA transcriptome when overexpressed in MCF-7 cells. Sci. Rep. 2019; 9:9430.

Mechanism research on the lupeol treatment on MCF-7 breast cancer cells based on cell metabonomics

2014 ◽  
Vol 32 (3) ◽  
pp. 278
Author(s):  
Dongdong SHI ◽  
Yuanyuan KUANG ◽  
Guiming WANG ◽  
Zhangxiao PENG ◽  
Yan WANG ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Mechanism Research ◽  
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Anticancer Potential of Calli Versus Seedling Extracts Derived from Rosmarinus officinalis and Coleus hybridus

2020 ◽  
Vol 21 (14) ◽  
pp. 1528-1538
Author(s):  
Sarah Albogami ◽  
Hadeer Darwish ◽  
Hala M. Abdelmigid ◽  
Saqer Alotaibi ◽  
Ahmed Nour El-Deen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Transcriptional Profiling ◽  
Significant Inhibition ◽  
Rosmarinus Officinalis ◽  
Crude Extracts ◽  
Incidence And Mortality ◽  
Mcf 7

Background: In Saudi Arabia, the incidence and mortality rates of breast cancer are high. Although current treatments are effective, breast cancer cells develop resistance to these treatments. Numerous studies have demonstrated that active compounds in plant extracts, such as the phenolic compound Rosmarinic Acid (RA), exert anti-cancer effects. Objective: We investigated the anticancer properties of methanolic crude extracts of seedlings and calli of Rosmarinus officinalis and Coleus hybridus, two Lamiaceae species. Methods: MCF-7 human breast cancer cells were treated with methanolic crude extracts obtained from plant calli and seedlings generated in vitro, and cell proliferation was evaluated. Transcriptional profiling of the seedling and callus tissues was also conducted. Results: The mRNA expression levels of RA genes were higher in C. hybridus seedlings than in R. officinalis seedlings, as well as in C. hybridus calli than in R. officinalis calli, except for TAT and C4H. In addition, seedling and callus extracts of both R. officinalis and C. hybridus showed anti-proliferative effects against MCF-7 cells after 24 or 48 h of treatment. Discussion: At a low concentration of 10 μg/mL, C. hybridus calli and seedling extracts showed the most significant anti-proliferative effects after 24 and 48 h of exposure (p < 0.01); controls (doxorubicin) also showed significant inhibition, but lesser than that observed with C. hybridus (p < 0.05). Results with R. officinalis callus and seedling extracts did not significantly differ from those with untreated cells. Conclusion: Methanolic extracts of R. officinalis and C. hybridus are potentially valuable options for breast cancer treatment.

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