scholarly journals Embryonic transcription factor SOX9 drives breast cancer endocrine resistance

2017 ◽  
Vol 114 (22) ◽  
pp. E4482-E4491 ◽  
Author(s):  
Rinath Jeselsohn ◽  
MacIntosh Cornwell ◽  
Matthew Pun ◽  
Gilles Buchwalter ◽  
Mai Nguyen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Cells ◽  
Endocrine Resistance ◽  
Tamoxifen Resistance ◽  
Clinical Samples ◽  
Breast Cancers ◽  
Primary Target ◽  
Metastatic Phenotype ◽  
Clinical Observations ◽  
Tamoxifen Resistant

The estrogen receptor (ER) drives the growth of most luminal breast cancers and is the primary target of endocrine therapy. Although ER blockade with drugs such as tamoxifen is very effective, a major clinical limitation is the development of endocrine resistance especially in the setting of metastatic disease. Preclinical and clinical observations suggest that even following the development of endocrine resistance, ER signaling continues to exert a pivotal role in tumor progression in the majority of cases. Through the analysis of the ER cistrome in tamoxifen-resistant breast cancer cells, we have uncovered a role for an RUNX2–ER complex that stimulates the transcription of a set of genes, including most notably the stem cell factor SOX9, that promote proliferation and a metastatic phenotype. We show that up-regulation of SOX9 is sufficient to cause relative endocrine resistance. The gain of SOX9 as an ER-regulated gene associated with tamoxifen resistance was validated in a unique set of clinical samples supporting the need for the development of improved ER antagonists.

scholarly journals Inhibiting PAD2 enhances the anti-tumor effect of docetaxel in tamoxifen-resistant breast cancer cells

2019 ◽  
Vol 38 (1) ◽  
Author(s):  
Fujun Li ◽  
Lixia Miao ◽  
Teng Xue ◽  
Hao Qin ◽  
Santanu Mondal ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Combination Treatment ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Nuclear Accumulation ◽  
Breast Cancers ◽  
Inhibition Of Proliferation ◽  
Tamoxifen Resistant

Abstract Background Tamoxifen resistance presents a huge clinical challenge for breast cancer patients. An understanding of the mechanisms of tamoxifen resistance can guide development of efficient therapies to prevent drug resistance. Methods We first tested whether peptidylarginine deiminase 2 (PAD2) may be involved in tamoxifen-resistance in breast cancer cells. The effect of depleting or inhibiting PAD2 in tamoxifen-resistant MCF-7 (MCF7/TamR) cells was evaluated both in vitro and in vivo. We then investigated the potential of Cl-amidine, a PAD inhibitor, to be used in combination with tamoxifen or docetaxel, and further explored the mechanism of the synergistic and effective drug regimen of PADs inhibitor and docetaxel on tamoxifen-resistant breast cancer cells. Results We report that PAD2 is dramatically upregulated in tamoxifen-resistant breast cancer. Depletion of PAD2 in MCF7/TamR cells facilitated the sensitivity of MCF7/TamR cells to tamoxifen. Moreover, miRNA-125b-5p negatively regulated PAD2 expression in MCF7/TamR cells, therefore overexpression of miR-125b-5p also increased the cell sensitivity to tamoxifen. Furthermore, inhibiting PAD2 with Cl-amidine not only partially restored the sensitivity of MCF7/TamR cells to tamoxifen, but also more efficiently enhanced the efficacy of docetaxel on MCF7/TamR cells with lower doses of Cl-amidine and docetaxel both in vivo and in vivo. We then showed that combination treatment with Cl-amidine and docetaxel enhanced p53 nuclear accumulation, which synergistically induced cell cycle arrest and apoptosis. Meanwhile, p53 activation in the combination treatment also accelerated autophagy processes by synergistically decreasing the activation of Akt/mTOR signaling, thus enhancing the inhibition of proliferation. Conclusion Our results suggest that PAD2 functions as an important new biomarker for tamoxifen-resistant breast cancers and that inhibiting PAD2 combined with docetaxel may offer a new approach to treatment of tamoxifen-resistant breast cancers.

scholarly journals Inhibition of O-GlcNAc transferase activates tumor-suppressor gene expression in tamoxifen-resistant breast cancer cells

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anna Barkovskaya ◽  
Kotryna Seip ◽  
Lina Prasmickaite ◽  
Ian G. Mills ◽  
Siver A. Moestue ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Suppressor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Breast Cancers ◽  
Number Of Patients ◽  
Tamoxifen Resistant ◽  
Glcnac Transferase

Abstract In this study, we probed the importance of O-GlcNAc transferase (OGT) activity for the survival of tamoxifen-sensitive (TamS) and tamoxifen-resistant (TamR) breast cancer cells. Tamoxifen is an antagonist of estrogen receptor (ERα), a transcription factor expressed in over 50% of breast cancers. ERα-positive breast cancers are successfully treated with tamoxifen; however, a significant number of patients develop tamoxifen-resistant disease. We show that in vitro development of tamoxifen-resistance is associated with increased sensitivity to the OGT small molecule inhibitor OSMI-1. Global transcriptome profiling revealed that TamS cells adapt to OSMI-1 treatment by increasing the expression of histone genes. This is known to mediate chromatin compaction. In contrast, TamR cells respond to OGT inhibition by activating the unfolded protein response and by significantly increasing ERRFI1 expression. ERRFI1 is an endogenous inhibitor of ERBB-signaling, which is a known driver of tamoxifen-resistance. We show that ERRFI1 is selectively downregulated in ERα-positive breast cancers and breast cancers driven by ERBB2. This likely occurs via promoter methylation. Finally, we show that increased ERRFI1 expression is associated with extended survival in patients with ERα-positive tumors (p = 9.2e−8). In summary, we show that tamoxifen-resistance is associated with sensitivity to OSMI-1, and propose that this is explained in part through an epigenetic activation of the tumor-suppressor ERRFI1 in response to OSMI-1 treatment.

scholarly journals Histone methyltransferases regulate the transcriptional expression of ERα and the proliferation of tamoxifen-resistant breast cancer cells

2020 ◽  
Vol 180 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Seung-Su Kim ◽  
Min-Ho Lee ◽  
Mi-Ock Lee
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Chromatin Immunoprecipitation ◽  
Breast Cancer Cells ◽  
Methylation Status ◽  
Endocrine Resistance ◽  
Breast Cancers ◽  
Histone Methyltransferases ◽  
Expression Levels ◽  
Tamoxifen Resistant

Abstract Purpose Although tamoxifen remains the frontline treatment for ERα-positive breast cancers, resistance to this drug limits its clinical efficacy. Most tamoxifen-resistant patients retain ERα expression which may support growth and progression of breast cancers. Therefore, we investigated epigenetic regulation of ERα that may provide a rationale for targeting ERα in these patients. Methods Expression levels of the mixed-lineage leukemia (MLL) family of proteins in tamoxifen-resistant breast cancer cells and publicly available breast cancer patient data sets were analyzed. Histone methylation levels in ERα promoter regions were assessed using chromatin immunoprecipitation. Expression levels of ERα and its target gene were analyzed using western blotting and real-time qPCR. Cell-cycle was analyzed by flow cytometry. Results The expression of MLL3 and SET-domain-containing 1A (SET1A) were increased in tamoxifen-resistant breast cancers. An MLL3 chromatin immunoprecipitation-sequencing data analysis and chromatin immunoprecipitation experiments for MLL3 and SET1A suggested that these proteins bound to enhancer or intron regions of the ESR1 gene and regulated histone H3K4 methylation status. Depletion of MLL3 or SET1A downregulated the expression level of ERα and inhibited the growth of tamoxifen-resistant breast cancer cells. Additional treatment with fulvestrant resulted in a synergistic reduction of ERα levels and the growth of the cells. Conclusions The enhanced expression of MLL3 and SET1A in tamoxifen-resistant breast cancer cells supported the ERα-dependent growth of these cells by increasing ERα expression. Our results suggest that targeting these histone methyltransferases might provide an attractive strategy to overcome endocrine resistance.

scholarly journals Transcriptional coregualtor NUPR1 maintains tamoxifen resistance in breast cancer cells

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Lingling Wang ◽  
Jiashen Sun ◽  
Yueyuan Yin ◽  
Yanan Sun ◽  
Jinyi Ma ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Critical Role ◽  
Endocrine Resistance ◽  
Autophagic Flux ◽  
Physical Interaction ◽  
Premature Senescence ◽  
Breast Cancers ◽  
Transcriptional Coregulator

AbstractTo support cellular homeostasis and mitigate chemotherapeutic stress, cancer cells must gain a series of adaptive intracellular processes. Here we identify that NUPR1, a tamoxifen (Tam)-induced transcriptional coregulator, is necessary for the maintenance of Tam resistance through physical interaction with ESR1 in breast cancers. Mechanistically, NUPR1 binds to the promoter regions of several genes involved in autophagy process and drug resistance such as BECN1, GREB1, RAB31, PGR, CYP1B1, and regulates their transcription. In Tam-resistant ESR1 breast cancer cells, NUPR1 depletion results in premature senescence in vitro and tumor suppression in vivo. Moreover, enforced-autophagic flux augments cytoplasmic vacuolization in NUPR1-depleted Tam resistant cells, which facilitates the transition from autophagic survival to premature senescence. Collectively, these findings suggest a critical role for NUPR1 as a transcriptional coregulator in enabling endocrine persistence of breast cancers, thus providing a vulnerable diagnostic and/or therapeutic target for endocrine resistance.

scholarly journals Poly-ADP-Ribosylation of Estrogen Receptor-Alpha by PARP1 Mediates Antiestrogen Resistance in Human Breast Cancer Cells

Cancers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 43 ◽  
Author(s):  
Nicholas Pulliam ◽  
Jessica Tang ◽  
Weini Wang ◽  
Fang Fang ◽  
Riddhi Sood ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Oxidative Stress ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Tamoxifen Resistance ◽  
Tamoxifen Treatment ◽  
Dependent Manner ◽  
Tamoxifen Resistant

Therapeutic targeting of estrogen receptor-α (ERα) by the anti-estrogen tamoxifen is standard of care for premenopausal breast cancer patients and remains a key component of treatment strategies for postmenopausal patients. While tamoxifen significantly increases overall survival, tamoxifen resistance remains a major limitation despite continued expression of ERα in resistant tumors. Previous reports have described increased oxidative stress in tamoxifen resistant versus sensitive breast cancer and a role for PARP1 in mediating oxidative damage repair. We hypothesized that PARP1 activity mediated tamoxifen resistance in ERα-positive breast cancer and that combining the antiestrogen tamoxifen with a PARP1 inhibitor (PARPi) would sensitize tamoxifen resistant cells to tamoxifen therapy. In tamoxifen-resistant vs. -sensitive breast cancer cells, oxidative stress and PARP1 overexpression were increased. Furthermore, differential PARylation of ERα was observed in tamoxifen-resistant versus -sensitive cells, and ERα PARylation was increased by tamoxifen treatment. Loss of ERα PARylation following treatment with a PARP inhibitor (talazoparib) augmented tamoxifen sensitivity and decreased localization of both ERα and PARP1 to ERα-target genes. Co-administration of talazoparib plus tamoxifen increased DNA damage accumulation and decreased cell survival in a dose-dependent manner. The ability of PARPi to overcome tamoxifen resistance was dependent on ERα, as lack of ERα-mediated estrogen signaling expression and showed no response to tamoxifen-PARPi treatment. These results correlate ERα PARylation with tamoxifen resistance and indicate a novel mechanism-based approach to overcome tamoxifen resistance in ER+ breast cancer.

Molecular Changes in Tamoxifen-Resistant Breast Cancer: Relationship Between Estrogen Receptor, HER-2, and p38 Mitogen-Activated Protein Kinase

2005 ◽  
Vol 23 (11) ◽  
pp. 2469-2476 ◽  
Author(s):  
M. Carolina Gutierrez ◽  
Simone Detre ◽  
Stephen Johnston ◽  
Syed K. Mohsin ◽  
Jiang Shou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Protein Kinase ◽  
Tamoxifen Resistance ◽  
Mitogen Activated Protein Kinase ◽  
Clinical Samples ◽  
Strong Correlations ◽  
Mitogen Activated Protein ◽  
Her 2 ◽  
Tamoxifen Resistant

Purpose To evaluate growth factor receptor cross talk with the estrogen receptor (ER) in paired clinical breast cancer specimens and in a xenograft model before tamoxifen and at tumor progression as a possible mechanism for tamoxifen resistance. Methods Specimen pairs from 39 patients were tissue arrayed and stained for ER, progesterone receptor (PgR), Bcl-2, c-ErbB2 (HER-2), and phosphorylated (p) p38 mitogen-activated protein kinase (MAPK), p-ERK1/2 MAPK, and p-Akt. Xenograft MCF-7 tumors before and after tamoxifen resistance were assessed for levels of p-p38. Results Pretreatment, there were strong correlations between ER, PgR, and Bcl-2, and an inverse correlation between ER and HER-2. These correlations were lost in the tamoxifen- resistant tumors and replaced by strong correlations between ER and p-p38 and p-ERK. ER expression was lost in 17% of resistant tumors. Three (11%) of the 26 tumors originally negative for HER-2 became amplified and/or overexpressed at resistance. All ER-positive tumors that overexpressed HER-2 originally or at resistance expressed high levels of p-p38. In the pretreatment and tamoxifen-resistant specimens, there were strong correlations between p-p38 and p-ERK. In the tamoxifen-resistant xenograft tumors, like the clinical samples, there was a striking increase in p-p38. Conclusion The molecular pathways driving tumor growth can change as the tumor progresses. Crosstalk between ER, HER-2, p38, and ERK may contribute to tamoxifen resistance and may provide molecular targets to overcome this resistance.

scholarly journals LAMP3 is involved in tamoxifen resistance in breast cancer cells through the modulation of autophagy

2014 ◽  
Vol 21 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Anika Nagelkerke ◽  
Anieta M Sieuwerts ◽  
Johan Bussink ◽  
Fred C G J Sweep ◽  
Maxime P Look ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mrna Expression ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Tamoxifen Treatment ◽  
Breast Cancer Patients ◽  
Mcf7 Cells ◽  
First Line ◽  
Tamoxifen Resistant

Lysosome-associated membrane protein 3 (LAMP3) is a member of the LAMP-family of proteins, which are involved in the process of autophagy. Autophagy is induced by tamoxifen in breast cancer cells and may contribute to tamoxifen resistance. In this study, the significance of LAMP3 for tamoxifen resistance in breast cancer was examined. The methods employed included use of clonogenic assays to assess the survival of MCF7 breast cancer cells with LAMP3 knockdown after tamoxifen treatment and of quantitative real-time PCR of LAMP3 to evaluate its predictive value for first-line tamoxifen treatment in patients with advanced breast cancer. Results show that tamoxifen treatment of MCF7 cells induced LAMP3 mRNA expression. LAMP3 knockdown in these cells increased tamoxifen sensitivity. Evaluation of expression of the autophagy markers, LC3B and p62, after LAMP3 knockdown showed increased expression levels, indicating that cells with LAMP3 knockdown have a suppressed ability to complete the autophagic process. In addition, knockdown of autophagy-associated genes resulted in sensitization to tamoxifen. Next, tamoxifen-resistant MCF7 cells were cultured. These cells had a sevenfold higher LAMP3 mRNA expression, showed elevated basal autophagy levels, and could be significantly resensitized to tamoxifen by LAMP3 knockdown. In patients treated with first-line tamoxifen for advanced disease (n=304), high LAMP3 mRNA expression was associated with shorter progression-free survival (P=0.003) and shorter post-relapse overall survival (P=0.040), also in multivariate analysis. Together, these results indicate that LAMP3 contributes to tamoxifen resistance in breast cancer. Tamoxifen-resistant cells are resensitized to tamoxifen by the knockdown of LAMP3. Therefore, LAMP3 may be clinically relevant to countering tamoxifen resistance in breast cancer patients.

scholarly journals miR-489 confines uncontrolled estrogen signaling through a negative feedback mechanism and regulates tamoxifen resistance in breast cancer

2020 ◽  
Author(s):  
Mithil Soni ◽  
Ozge Saatci ◽  
Yogin Patel ◽  
Manikanda Raja Keerthi Raja ◽  
Xinfeng Liu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cell Lines ◽  
Tamoxifen Resistance ◽  
Resistant Cell ◽  
Estrogen Signaling ◽  
Breast Cancers ◽  
Tamoxifen Resistant ◽  
Hormonal Therapies

Abstract Background Approximately 75% of diagnosed breast cancer tumors are Estrogen receptor (ER) positive tumors and are associated with better prognosis due to their response to hormonal therapies. However, around 40% of patients relapse after hormonal therapies. In the current study, we aimed to evaluate miR-489 as a novel molecular target to combat tamoxifen resistance.Methods Genomic analysis of gene expression profiles in primary breast cancers and tamoxifen resistant cell lines unveiled the potential role of miR-489 in regulation of estrogen signaling and development of tamoxifen resistance. We manipulated miR-489 expression in breast cancer cell lines by transient transfection of miR-489 mimic or establishment of knockout cell lines using the CRISPR/Cas9 system to study the reciprocal regulation of miR-489 and estrogen/ER signaling pathways. Cell proliferation, tumor sphere formation assay and flow cytometry analysis were conducted to investigate the role of miR-489 on estrogen-induced cell proliferation, cancer stem cells expansion and development of tamoxifen resistance.Results miR-489 expression was significantly downregulated in tamoxifen-resistant cell lines. Low levels of miR-489 were associated with poor clinical outcomes in patients with hormone treatment. In vitro analysis showed that loss of miR-489 expression promoted tamoxifen resistance while overexpression of miR-489 in tamoxifen-resistant cells restored tamoxifen sensitivity. Mechanistically, we found that miR-489 is an estrogen regulated miRNA that negatively regulated estrogen receptor signaling by using at least the following two mechanisms: i) modulation of ER phosphorylation status by inhibiting MAPK and AKT kinase activities; ii) regulation of nucleus to cytosol translocation of estrogen receptor α (ERα) by decreasing p38 expression and consequently ER phosphorylation. In addition, miR-489 could break the positive feed-forward loop between estrogen-ERα axis and p38 MAPK in breast cancer cells which was necessary for its function as transcription factor.Conclusion Our study unveiled the underlying molecular mechanism by which miR-489 regulates estrogen signaling pathway through a negative feedback loop and uncovered its role in the development of and overcoming tamoxifen resistance in breast cancers.

scholarly journals HDAC5-mediated deacetylation and nuclear localisation of SOX9 is critical for tamoxifen resistance in breast cancer

2019 ◽  
Vol 121 (12) ◽  
pp. 1039-1049 ◽  
Author(s):  
Yue Xue ◽  
Wenwen Lian ◽  
Jiaqi Zhi ◽  
Wenjuan Yang ◽  
Qianjin Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Nuclear Translocation ◽  
Tamoxifen Resistance ◽  
Nuclear Localisation ◽  
Tamoxifen Resistant ◽  
Factor C ◽  
Positive Breast Cancer

Abstract Background Tamoxifen resistance remains a significant clinical challenge for the therapy of ER-positive breast cancer. It has been reported that the upregulation of transcription factor SOX9 in ER+ recurrent cancer is sufficient for tamoxifen resistance. However, the mechanisms underlying the regulation of SOX9 remain largely unknown. Methods The acetylation level of SOX9 was detected by immunoprecipitation and western blotting. The expressions of HDACs and SIRTs were evaluated by qRT-PCR. Cell growth was measured by performing MTT assay. ALDH-positive breast cancer stem cells were evaluated by flow cytometry. Interaction between HDAC5 and SOX9 was determined by immunoprecipitation assay. Results Deacetylation is required for SOX9 nuclear translocation in tamoxifen-resistant breast cancer cells. Furthermore, HDAC5 is the key deacetylase responsible for SOX9 deacetylation and subsequent nuclear translocation. In addition, the transcription factor C-MYC directly promotes the expression of HDAC5 in tamoxifen resistant breast cancer cells. For clinical relevance, high SOX9 and HDAC5 expression are associated with lower survival rates in breast cancer patients treated with tamoxifen. Conclusions This study reveals that HDAC5 regulated by C-MYC is essential for SOX9 deacetylation and nuclear localisation, which is critical for tamoxifen resistance. These results indicate a potential therapy strategy for ER+ breast cancer by targeting C-MYC/HDAC5/SOX9 axis.

scholarly journals Narciclasine Targets STAT3 via Distinct Mechanisms in Tamoxifen-Resistant Breast Cancer Cells

2021 ◽  
Author(s):  
Chao Lv ◽  
Yun Huang ◽  
Rui Huang ◽  
Qun Wang ◽  
Hongwei Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Sh2 Domain ◽  
Breast Cancers ◽  
Stat3 Phosphorylation ◽  
Er Positive ◽  
Tamoxifen Resistant ◽  
Mcf 7 ◽  
Positive Breast Cancer

Abstract Background: Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in multiple malignant tumors. Compared with regular estrogen receptor (ER)-positive breast cancers, the patients with tamoxifen-resistant breast cancers often exhibit higher level of STAT3 phosphorylation. Narciclasine (Nar) possesses strong inhibiting effects against a variety of cancer cells, however, the underlying antitumor target(s)/mechanism(s) remains barely understood. Methods: Targets prediction of narciclasine was performed by combining connectivity map (CMAP) and drug affinity responsive target stability (DARTS) strategy. Molecular and biochemical methods were used to elucidate the distinct mechanisms of narciclasine targeting STAT3. The narciclasine nano-delivery system was synthesized by thin film hydration method. Xenograft models were established to determine antitumor activity of narciclasine and its liposome in vivo.Results: In this study, we successfully identified the STAT3 was the direct target of Nar through the combination strategies of CMAP and DARTS. In ER-positive breast cancer cells, Nar could suppress phosphorylation, activation, dimerization, and nuclear translocation of STAT3 by directly binding with the STAT3 SH2 domain. Additionally, Nar could also specifically promote total STAT3 degradation via proteasome pathway and reduce the STAT3 protein stability in tamoxifen-resistant breast cancer cells (MCF-7/TR). This distinct mechanism of Nar targeting STAT3 was mainly attributed to the various levels of reactive oxygen species (ROS) in regular and tamoxifen-resistant ER-positive breast cancer cells. Meanwhile, Nar loaded nanoparticles could markedly decrease the protein levels of STAT3 in tumor sites, resulting in significant MCF-7/TR xenograft tumor regression without obvious toxicity. Conclusions: Our findings successfully highlight the STAT3 as the direct therapeutic target of Nar in ER-positive breast cancer cells, especially Nar leaded STAT3 degradation as a promising strategy for the tamoxifen-resistant breast cancer treatment.

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