466 K-ras and Aryl Hydrocarbon Receptor Expression in Triple Negative Breast Cancers

2012 ◽  
Vol 48 ◽  
pp. 144
Author(s):  
J. Lee ◽  
W. Kim ◽  
W. Lee ◽  
J. Lee
Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2559 ◽  
Author(s):  
Donovan ◽  
Selmin ◽  
Doetschman ◽  
Romagnolo

Triple negative breast cancers (TNBC) are the most aggressive and lethal breast cancers (BC). The aryl hydrocarbon receptor (AHR) is often overexpressed in TNBC, and its activation results in the epigenetic silencing of BRCA1, which is a necessary factor for the transcriptional activation of estrogen receptor (ER)α. The dietary isoflavone genistein (GEN) modulates BRCA1 CpG methylation in BC cells. The purpose of this study was to investigate the effect of GEN on BRCA1 epigenetic regulation and AHR activity in vivo and TNBC cells. Mice were administered a control or GEN-enriched (4 and 10 ppm) diet from gestation through post-natal day 50. Mammary tissue was analyzed for changes in BRCA1 regulation and AhR activity. TNBC cells with constitutively hypermethylated BRCA1 (HCC38) and MCF7 cells were used. Protein levels and mRNA expression were measured by Western blot and real-time PCR, respectively. BRCA1 promoter occupancy and CpG methylation were analyzed by chromatin immunoprecipitation and methylation-specific PCR, respectively. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. GEN administered in the diet dose-dependently decreased basal Brca1 methylation and AHR activity in the mammary gland of adult mice. HCC38 cells were found to overexpress constitutively active AHR in parallel with BRCA1 hypermethylation. The treatment of HCC38 cells with GEN upregulated BRCA1 protein levels, which was attributable to decreased CpG methylation and AHR binding at BRCA1 exon 1a. In MCF7 cells, GEN prevented the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-dependent localization of AHR at the BRCA1 gene. These effects were consistent with those elicited by control AHR antagonists galangin (GAL), CH-223191, and α-naphthoflavone. The pre-treatment with GEN sensitized HCC38 cells to the antiproliferative effects of 4-hydroxytamoxifen. We conclude that the dietary compound GEN may be effective for the prevention and reversal of AHR-dependent BRCA1 hypermethylation, and the restoration of ERα-mediated response, thus imparting the sensitivity of TNBC to antiestrogen therapy.


Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 763 ◽  
Author(s):  
Justin M Brown ◽  
Marie-Claire D Wasson ◽  
Paola Marcato

Treatment decisions for breast cancer are based on staging and hormone receptor expression and include chemotherapies and endocrine therapy. While effective in many cases, some breast cancers are resistant to therapy, metastasize and recur, leading to eventual death. Higher percentages of tumor-initiating cancer stem cells (CSCs) may contribute to the increased aggressiveness, chemoresistance, and worse outcomes among breast cancer. This may be particularly true in triple-negative breast cancers (TNBCs) which have higher percentages of CSCs and are associated with worse outcomes. In recent years, increasing numbers of long non-coding RNAs (lncRNAs) have been identified as playing an important role in breast cancer progression and some of these have been specifically associated within the CSC populations of breast cancers. LncRNAs are non-protein-coding transcripts greater than 200 nucleotides which can have critical functions in gene expression regulation. The preclinical evidence regarding lncRNA antagonists for the treatment of cancer is promising and therefore, presents a potential novel approach for treating breast cancer and targeting therapy-resistant CSCs within these tumors. Herein, we summarize the lncRNAs that have been identified as functionally relevant in breast CSCs. Furthermore, our review of the literature and analysis of patient datasets has revealed that many of these breast CSC-associated lncRNAs are also enriched in TNBC. Together, this suggests that these lncRNAs may be playing a particularly important role in TNBC. Thus, certain breast cancer-promoting/CSC-associated lncRNAs could be targeted in the treatment of TNBCs and the CSCs within these tumors should be susceptible to anti-lncRNA therapy.


2010 ◽  
Vol 321 (2) ◽  
pp. 253-257 ◽  
Author(s):  
Georg Kretzschmar ◽  
Anja Papke ◽  
Oliver Zierau ◽  
Frank Josef Möller ◽  
Svjetlana Medjakovic ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Mariana A. Callero ◽  
Andrea I. Loaiza-Pérez

Many estrogen-receptor- (ER-) expressing breast cancers become refractory to ER-based therapies. New antitumor drugs like aminoflavone (AF) and benzothiazoles (Bzs) have been developed and have exquisite antitumor activity in ER+MCF-7 and T47D cells and in a MCF-7 nude mouse model. ER(−) breast cancer cells like MDA-MB-231 are less susceptible. We previously found in MCF-7 cells that these drugs activate the aryl hydrocarbon receptor (AhR) via translocation to the nucleus, induction of AhR-specific DNA binding activity, and expression of CYP1A1, whose transcription is controlled by the AhR-ARNT transcription factor. CYP1A1 metabolizes AF and Bz to a species which directly or after further metabolism damages DNA. In contrast an AhR-deficient variant of MCF-7 or cells with predominantly nuclear AhR expression, such as MDA-MB 231, are resistant. Thus, these drugs, unlike other neoplastic agents, require AhR-mediated signaling to cause DNA damage. This is a new treatment strategy for breast cancers with intact AhR signaling.


2015 ◽  
Vol 33 (28_suppl) ◽  
pp. 159-159
Author(s):  
Nathaniel L. Jones ◽  
Joanne Xiu ◽  
Sandeep K. Reddy ◽  
Jason Dennis Wright ◽  
William M. Burke ◽  
...  

159 Background: “Triple negative” has been used to characterize a subtype of breast cancer that lacks estrogen, progesterone, and HER2 receptor expression. They are aggressive cancers with limited treatment options. It’s unknown if similar phenotype found in other cancer types, like endometrial cancer, harbor similar molecular alterations and prognosis. We aim to compare molecular features between TNEC and TNBC. Methods: A total of 3133 endometrial cancer samples were evaluated by Caris Life Sciences (Phoenix, AZ) from Mar, 2011 to Jul, 2014 by multiplatform profiling, which included a combination of sequencing (Sanger or NGS), protein expression (IHC), and/or gene amplification (CISH or FISH). 545 TNEC and 2049 TNBC were identified based on reported pathology and compared using Fisher exact tests. Results: Compared to an incidence of 15-20% TNBC in breast cancer, 17% (545/3133) TNEC was seen in our cohort, of which 13% were endometrioid, 22% serous, 26% carcinosarcoma, 7% clear cell, and 22% other. Compared with TNBC, TNEC showed 1.9 exonic mutations per case while TNBC showed 1.2 mutations per case. As shown in the table, AR expression is lower in TNEC than TNBC. TP53 mutation was common in both but more frequent in TNBC. While BRCA1/2 mutation rates were similar, low MGMT and ERCC1 were more common in TNEC, suggesting increased aberrant DNA repair. DNA synthesis protein expression was higher in TNEC including TS, RRM1, and TOPO2A, although TNBC had higher TOPO1. PD-1 expression was more common in TNEC suggesting immune pathway involvement. PI3K/AKT/mTor, MAPK and Wnt pathways were more involved in TNEC with greater PTEN, PIK3CA, FBXW7, KRAS and CTNNB1 mutations. Conclusions: Our study reveals significantly higher overall mutation rates in TNEC than TNBC, and specifically higher activations of multiple molecular pathways including PI3K/Akt/mTor, MAPK and Wnt. Further studies are warranted to validate these findings in clinical trials.


FEBS Journal ◽  
2013 ◽  
Vol 280 (24) ◽  
pp. 6681-6690 ◽  
Author(s):  
Natalie Stobbe-Maicherski ◽  
Sandra Wolff ◽  
Christian Wolff ◽  
Josef Abel ◽  
Ulrich Sydlik ◽  
...  

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