scholarly journals miR-221/222 sponge abrogates tamoxifen resistance in ER-positive breast cancer cells through restoring the expression of ERα

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yan Xiu Ouyang ◽  
Jun Feng ◽  
Zun Wang ◽  
Guo Jun Zhang ◽  
Min Chen
Keyword(s):  
Breast Cancer ◽  
Tamoxifen Resistance ◽  
Cancer Cell Line ◽  
Breast Cancer Patients ◽  
Cmv Promoter ◽  
Pulldown Assay ◽  
Er Positive ◽  
Resistant Breast Cancer Cell ◽  
Mcf 7 ◽  
Positive Breast Cancer

AbstractTamoxifen resistance (TamR) prevents ER-positive breast cancer patients from benefitting from endocrine therapy, and miR-221 or miR-222 plays vital roles in inducing TamR. In this study, we designed synthetic sponges to reverse TamR by targeting these two miRs. First, we established a tamoxifen resistant breast cancer cell line (MCF-7TamR), we verified the high expressing level of these two miRs in TamR cells. miR-221 or miR-222 inhibitors rendered MCF-7TamR cells responsive to tamoxifen. Next, we designed a miR-221/222 sponge, which contains total 8 multi-antisense binding sites (MBSs) for these two onco-miRs, and inserted it into CMV promoter- or hTERT promoter-driven expressing vectors. After transfected miR-221/222 sponge expressing vectors into MCF-7TamR cells, we identified a strong interaction between miR-221/222 sponge and endogenous miR-221 or miR-222 by RNA pulldown assay. We also found that miR-221/222 sponge restored the expression of ERα and PTEN, arrested cells in G1 phase, and finally resulted in reduced cell growth and cell migration. Notably, miR-221/222 sponge expressing cells abrogates tamoxifen resistance through restoring the expression of ERα, suggesting that miR-221/222 sponge gene therapy especially driven by tumor specific promoter could provide an effective therapeutic approach against TamR in breast cancer.

scholarly journals miR-200 affects tamoxifen resistance in breast cancer cells through regulation of MYB

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yu Gao ◽  
Wenzhi Zhang ◽  
Chengwen Liu ◽  
Guanghua Li
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Breast Cancer Patients ◽  
Over Expression ◽  
Er Positive ◽  
Emt Markers ◽  
Mcf 7 ◽  
Positive Breast Cancer

AbstractResistance to tamoxifen is a major clinical challenge. Research in recent years has identified epigenetic changes as mediated by dysregulated miRNAs that can possibly play a role in resistance to tamoxifen in breast cancer patients expressing estrogen receptor (ER). We report here elevated levels of EMT markers (vimentin and ZEB1/2) and reduced levels of EMT-regulating miR-200 (miR-200b and miR-200c) in ER-positive breast cancer cells, MCF-7, that were resistant to tamoxifen, in contrast with the naïve parental MCF-7 cells that were sensitive to tamoxifen. Further, we established regulation of c-MYB by miR-200 in our experimental model. C-MYB was up-regulated in tamoxifen resistant cells and its silencing significantly decreased resistance to tamoxifen and the EMT markers. Forced over-expression of miR-200b/c reduced c-MYB whereas reduced expression of miR-200b/c resulted in increased c-MYB We further confirmed the results in other ER-positive breast cancer cells T47D cells where forced over-expression of c-MYB resulted in induction of EMT and significantly increased resistance to tamoxifen. Thus, we identify a novel mechanism of tamoxifen resistance in breast tumor microenvironment that involves miR-200-MYB signaling.

scholarly journals Effect of Wnt5a on drug resistance in estrogen receptor-positive breast cancer

2020 ◽  
Author(s):  
Ai Amioka ◽  
Takayuki Kadoya ◽  
Satoshi Sueoka ◽  
Yoshie Kobayashi ◽  
Shinsuke Sasada ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Poor Prognosis ◽  
Breast Cancer Tissue ◽  
Cancer Tissue ◽  
Breast Cancer Patients ◽  
Mtor Signaling Pathway ◽  
The Poor ◽  
Er Positive ◽  
Mcf 7 ◽  
Positive Breast Cancer

Abstract BackgroundIt was previously reported by us that Wnt5a-positive breast cancer can be classified as estrogen receptor (ER)-positive breast cancer and its prognosis is worse than that of Wnt5a-negative breast cancer. Herein, the molecular mechanisms underlying the poor prognosis of Wnt5a-positive breast cancer patients were examined. MethodsA total of 151 consecutive ER-positive breast cancer patients who underwent resection between January 2011 and February 2014 were enrolled. DNA microarray and pathway analyses were performed conducted using MCF-7 cells stably expressing Wnt5a (MCF-7/Wnt5a(+)). Based on the results, cell viability and drug sensitivity assays as well as mutation analysis , were performed using culture cells and breast cancer tissue. The relationship between Wnt5a and the PI3K–AKT–mTOR signaling pathway was examined.ResultsThe relapse-free survival rate in patients with Wnt5a-positive breast cancer was significantly lower than that in patients with Wnt5a-negative breast cancer ( P = 0.047). DNA microarray data indicated that only the cytochrome P450 (CYP) pathway was significantly upregulated in MCF-7/Wnt5a(+) cells ( P = 0.0440). MCF-7/Wnt5a(+) cells showed reduced sensitivity to the metabolic substrates of CYP, tamoxifen ( P < 0.001), and paclitaxel ( P < 0.001). PIK3CA mutations were unrelated to Wnt5a expression in breast cancer tissue and culture cells.ConclusionsIn ER-positive breast cancer, Wnt5a upregulated the CYP metabolic pathway; additionally, it inhibited the sensitivity to tamoxifen and paclitaxel, which constitute the standard treatment options for ER-positive breast cancer. Wnt5a could be involved in the poor prognosis of ER-positive breast cancer independently of the PI3K–AKT–mTOR signaling pathway.

scholarly journals Cytotoxic Effects of Hellebrigenin and Arenobufagin Against Human Breast Cancer Cells

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu Zhang ◽  
Bo Yuan ◽  
Baolin Bian ◽  
Haiyu Zhao ◽  
Anna Kiyomi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cancer Cell Line ◽  
Therapeutic Strategies ◽  
Expression Level ◽  
Cycle Arrest ◽  
Er Positive ◽  
Mcf 7 ◽  
Positive Breast Cancer

Development of new therapeutic strategies for breast cancer is urgently needed due to the sustained emergence of drug resistance, tumor recurrence and metastasis. To gain a novel insight into therapeutic approaches to fight against breast cancer, the cytocidal effects of hellebrigenin (Helle) and arenobufagin (Areno) were investigated in human estrogen receptor (ER)-positive breast cancer cell line MCF-7 and triple-negative breast cancer cell line MDA-MB-231. Helle exhibited more potent cytotoxicity than Areno in both cancer cells, and MCF-7 cells were more susceptible to both drugs in comparison with MDA-MB-231 cells. Apoptotic-like morphological characteristics, along with the downregulation of the expression level of Bcl-2 and Bcl-xL and the upregulation of the expression level of Bad, were observed in Helle-treated MCF-7 cells. Helle also caused the activation of caspase-8, caspase-9, along with the cleavage of poly(ADP-ribose) polymerase in MCF-7 cells. Helle-mediated necrosis-like phenotype, as evidenced by the increased propidium iodide (PI)-positive cells was further observed. G2/M cell cycle arrest was also induced by Helle in the cells. Upregulation of the expression level of p21 and downregulation of the expression level of cyclin D1, cyclin E1, cdc25C and survivin were observed in MCF-7 cells treated with Helle and occurred in parallel with G2/M arrest. Autophagy was triggered in MCF-7 cells and the addition of wortmannin or 3-MA, two well-known autophagy inhibitors, slightly but significantly rescued the cells. Furthermore, similar alterations of some key molecules associated with the aforementioned biological phenomena were observed in MDA-MB-231 cells. Intriguingly, the numbers of PI-positive cells in Helle-treated MCF-7 cells were significantly reduced by wortmannin and 3-MA, respectively. In addition, Helle-triggered G2/M arrest was significantly corrected by wortmannin, suggesting autophagy induction contributed to Helle-induced cytotoxicity of breast cancer cells by modulating necrosis and cell cycle arrest. Collectively, our results suggested potential usefulness of both Helle and Areno in developing therapeutic strategies to treat patients with different types of breast cancer, especially ER-positive breast cancer.

scholarly journals Autoantibodies Specific to ERα are Involved in Tamoxifen Resistance in Hormone Receptor Positive Breast Cancer

Cells ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 750 ◽  
Author(s):  
Angela Maselli ◽  
Stefania Parlato ◽  
Rossella Puglisi ◽  
Carla Raggi ◽  
Massimo Spada ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Growth ◽  
Cancer Patients ◽  
Tamoxifen Resistance ◽  
Breast Cancer Patients ◽  
Hormone Receptor Positive ◽  
Molecular Events ◽  
Therapeutic Decisions ◽  
Er Positive ◽  
Positive Breast Cancer

Tamoxifen resistance is a major hurdle in the treatment of estrogen receptor (ER)-positive breast cancer. The mechanisms of tamoxifen resistance are not fully understood although several underlying molecular events have been suggested. Recently, we identified autoantibodies reacting with membrane-associated ERα (anti-ERα Abs) in sera of breast cancer patients, able to promote tumor growth. Here, we investigated whether anti-ERα Abs purified from sera of ER-positive breast cancer patients could contribute to tamoxifen resistance. Anti-ERα Abs inhibited tamoxifen-mediated effects on cell cycle and proliferation in MCF-7 cells. Moreover, anti-ERα Abs hampered the tamoxifen-mediated reduction of tumor growth in SCID mice xenografted with breast tumor. Notably, simvastatin-mediated disaggregation of lipid rafts, where membrane-associated ERα is embedded, restored tamoxifen sensitivity, preventing anti-ERα Abs effects. In conclusion, detection of serum anti-ERα Abs may help predict tamoxifen resistance and concur to appropriately inform therapeutic decisions concerning hormone therapy in ER-positive breast cancer patients.

scholarly journals The Utility of SOX2 and AGR2 Biomarkers as Early Predictors of Tamoxifen Resistance in ER-Positive Breast Cancer Patients

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yomna Zamzam ◽  
Yosra Abdelmonem Zamzam ◽  
Marwa Aboalsoud ◽  
Heba Harras
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Tamoxifen Resistance ◽  
Tamoxifen Treatment ◽  
Time To Failure ◽  
Breast Cancer Patients ◽  
Early Predictors ◽  
Er Positive ◽  
Group 1 ◽  
Positive Breast Cancer

Background. Despite the undeniable benefit of tamoxifen therapy for ER-positive breast cancer patients, approximately one-third of those patients either do not respond to tamoxifen or develop resistance. Thus, it is a crucial step to identify novel, reliable, and easily detectable biomarkers indicating resistance to this drug. Objective. The aim of this work is to explore SOX2 and AGR2 biomarker expression in the tumor tissue of ER-positive breast cancer patients in combination with the evaluation of serum AGR2 level of these patients in order to validate these biomarkers as early predictors of tamoxifen resistance. Methods. This study was conducted on 224 ER-positive breast cancer patients. All patients were primarily subjected to serum AGR2 levelling by ELISA and their breast cancer tissue immunostained for SOX2 and AGR2. After 5 years of follow-up, the patients were divided into 3 groups: group 1 was tamoxifen sensitive and groups 2 and 3 were tamoxifen resistant. Time to failure of tamoxifen treatment was considered the time from the beginning of tamoxifen therapy to the time of discovery of breast cancer recurrence or metastases (in months). Results. SOX2 and AGR2 biomarkers expression and serum AGR2 level were significantly higher in groups 2 and 3 in comparison to group 1, while the relationship between Her2 neu expression and Ki67 index in the 3 different groups was statistically nonsignificant. Lower SOX2 and AGR2 expression and low AGR2 serum levels in the studied patients of groups 2 and 3 were significantly associated with longer time-to-failure of tamoxifen treatment. According to the ROC curve, the combined use of studied markers validity was with a sensitivity of 100%, specificity of 96%, PPV 96%, and NPV 100% ( p < 0.001 ; AUC: 0.984). Conclusions. Integrated use of SOX2 and AGR2 biomarkers with serum AGR2 assay holds a promising hope for their future use as predictive markers for early detection of tamoxifen resistance in ER-positive breast cancer patients.

scholarly journals OCT1 Is a Poor Prognostic Factor for Breast Cancer Patients and Promotes Cell Proliferation via Inducing NCAPH

2021 ◽  
Vol 22 (21) ◽  
pp. 11505
Author(s):  
Takuya Ogura ◽  
Kotaro Azuma ◽  
Junichiro Sato ◽  
Keiichi Kinowaki ◽  
Ken-Ichi Takayama ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Proliferation ◽  
Prognostic Factor ◽  
Disease Free Survival ◽  
Breast Cancer Patients ◽  
Clinical Value ◽  
Poor Prognostic Factor ◽  
Er Positive ◽  
Mcf 7 ◽  
Positive Breast Cancer

Octamer transcription factor 1 (OCT1) is a transcriptional factor reported to be a poor prognostic factor in various cancers. However, the clinical value of OCT1 in breast cancer is not fully understood. In the present study, an immunohistochemical study of OCT1 protein was performed using estrogen receptor (ER)-positive breast cancer tissues from 108 patients. Positive OCT1 immunoreactivity (IR) was associated with the shorter disease-free survival (DFS) of patients (p = 0.019). Knockdown of OCT1 inhibited cell proliferation in MCF-7 breast cancer cells as well as its derivative long-term estrogen-deprived (LTED) cells. On the other hand, the overexpression of OCT1 promoted cell proliferation in MCF-7 cells. Using microarray analysis, we identified the non-structural maintenance of chromosomes condensin I complex subunit H (NCAPH) as a novel OCT1-taget gene in MCF-7 cells. Immunohistochemical analysis showed that NCAPH IR was significantly positively associated with OCT1 IR (p < 0.001) and that positive NCAPH IR was significantly related to the poor DFS rate of patients (p = 0.041). The knockdown of NCAPH inhibited cell proliferation in MCF-7 and LTED cells. These results demonstrate that OCT1 and its target gene NCAPH are poor prognostic factors and potential therapeutic targets for patients with ER-positive breast cancer.

scholarly journals miR-449a Suppresses Tamoxifen Resistance in Human Breast Cancer Cells by Targeting ADAM22

2018 ◽  
Vol 50 (1) ◽  
pp. 136-149 ◽  
Author(s):  
Jun Li ◽  
Mingjie Lu ◽  
Jiao Jin ◽  
Xiyi Lu ◽  
Tongpeng Xu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Luciferase Assay ◽  
Protein Protein Interaction ◽  
Er Positive ◽  
Tamoxifen Resistant ◽  
Mcf 7 ◽  
Positive Breast Cancer

Background/Aims: Most of estrogen receptor positive breast cancer patients respond well initially to endocrine therapies, but often develop resistance during treatment with selective estrogen receptor modulators (SERMs) such as tamoxifen. Altered expression and functions of microRNAs (miRNAs) have been reportedly associated with tamoxifen resistance. Thus, it is necessary to further elucidate the function and mechanism of miRNAs in tamoxifen resistance. Methods: Tamoxifen sensitivity was validated by using Cell Counting Kit-8 in tamoxifen-sensitive breast cancer cells (MCF-7, T47D) and tamoxifen-resistant cells (MCF-7/TAM, T47D/ TAM). Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression level of miR-449a in tamoxifen-sensitive/-resistant cells and patient serums. Dual-luciferase assay was used to identify the binding of miR-449a and predicted gene ADAM22. The expression level of ADAM22 was determined by qRT-PCR and western blotting in miR-449a +/- breast cancer cells. Subsequently, rescue experiments were carried out to identify the function of ADAM22 in miR-449a-reduced tamoxifen resistance. Finally, Gene ontology (GO) and Protein-protein interaction analyses were performed to evaluate the potential mechanisms of ADAM22 in regulating tamoxifen resistance. Results: MiR-449a levels were downregulated significantly in tamoxifen-resistant breast cancer cells when compared with their parental cells, as well as in clinical breast cancer serum samples. Overexpression of miR-449a re-sensitized the tamoxifen-resistant breast cancer cells, while inhibition of miR-449a conferred tamoxifen resistance in parental cells. Luciferase assay identified ADAM22 as a direct target gene of miR-449a. Additionally, silencing of ADAM22 could reverse tamoxifen resistance induced by miR-449a inhibition in ER-positive breast cancer cells. GO analysis results showed ADAM22 was mainly enriched in the biological processes of cell adhesion, cell differentiation, gliogenesis and so on. Protein-protein interaction analyses appeared that ADAM22 might regulate tamoxifen resistance through PPARG, LGI1, KRAS and LYN. Conclusion: Decreased miR-449a causes the upregulation of ADAM22, which induces tamoxifen resistance of breast cancer cells. These results suggest that miR-449a, functioning by targeting ADAM22, contributes to the mechanisms underlying breast cancer endocrine resistance, which may provide a potential therapeutic strategy in ER-positive breast cancers.

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