Tamoxifen Action in ER-Negative Breast Cancer

Breast cancer is a highly heterogeneous disease. Tamoxifen is a selective estrogen receptor (ER) modulator and is mainly indicated for the treatment of breast cancer in postmenopausal women and postsurgery neoadjuvant therapy in ER-positive breast cancers. Interestingly, 5-10% of the ER-negative breast cancers have also shown sensitivity to tamoxifen treatment. The involvement of molecular markers and/or signaling pathways independent of ER signaling has been implicated in tamoxifen sensitivity in the ER-negative subgroup. Studies reveal that variation in the expression of estrogen-related receptor alpha, ER subtype beta, tumor microenvironment, and epigenetics affects tamoxifen sensitivity. This review discusses the background of the research on the action of tamoxifen that may inspire future studies to explore effective therapeutic strategies for the treatment of ER-negative and triple-negative breast cancers, the latter being an aggressive disease with worse clinical outcome.

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Quadruple-negative breast cancer: novel implications for a new disease

Breast Cancer Research ◽

10.1186/s13058-020-01369-5 ◽

2020 ◽

Vol 22 (1) ◽

Author(s):

Shristi Bhattarai ◽

Geetanjali Saini ◽

Keerthi Gogineni ◽

Ritu Aneja

Keyword(s):

Breast Cancer ◽

Triple Negative ◽

Tumor Biology ◽

Therapeutic Strategies ◽

Future Research ◽

Disease Course ◽

Prognostic Role ◽

Aggressive Disease ◽

Novel Biomarkers

AbstractBased on the androgen receptor (AR) expression, triple-negative breast cancer (TNBC) can be subdivided into AR-positive TNBC and AR-negative TNBC, also known as quadruple-negative breast cancer (QNBC). QNBC characterization and treatment is fraught with many challenges. In QNBC, there is a greater paucity of prognostic biomarkers and therapeutic targets than AR-positive TNBC. Although the prognostic role of AR in TNBC remains controversial, many studies revealed that a lack of AR expression confers a more aggressive disease course. Literature characterizing QNBC tumor biology and uncovering novel biomarkers for improved management of the disease remains scarce. In this comprehensive review, we summarize the current QNBC landscape and propose avenues for future research, suggesting potential biomarkers and therapeutic strategies that warrant investigation.

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Estrogens and Progestogens in Triple Negative Breast Cancer: Do They Harm?

Cancers ◽

10.3390/cancers13112506 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2506

Author(s):

Mark van Barele ◽

Bernadette A. M. Heemskerk-Gerritsen ◽

Yvonne V. Louwers ◽

Mijntje B. Vastbinder ◽

John W. M. Martens ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative ◽

Hormone Replacement ◽

Breast Cancers ◽

Younger Women ◽

Alternative Pathways ◽

Increased Risk ◽

History Of ◽

Hormone Sensitive

Triple-negative breast cancers (TNBC) occur more frequently in younger women and do not express estrogen receptor (ER) nor progesterone receptor (PR), and are therefore often considered hormone-insensitive. Treatment of premenopausal TNBC patients almost always includes chemotherapy, which may lead to premature ovarian insufficiency (POI) and can severely impact quality of life. Hormone replacement therapy (HRT) is contraindicated for patients with a history of hormone-sensitive breast cancer, but the data on safety for TNBC patients is inconclusive, with a few randomized trials showing increased risk-ratios with wide confidence intervals for recurrence after HRT. Here, we review the literature on alternative pathways from the classical ER/PR. We find that for both estrogens and progestogens, potential alternatives exist for exerting their effects on TNBC, ranging from receptor conversion, to alternative receptors capable of binding estrogens, as well as paracrine pathways, such as RANK/RANKL, which can cause progestogens to indirectly stimulate growth and metastasis of TNBC. Finally, HRT may also influence other hormones, such as androgens, and their effects on TNBCs expressing androgen receptors (AR). Concluding, the assumption that TNBC is completely hormone-insensitive is incorrect. However, the direction of the effects of the alternative pathways is not always clear, and will need to be investigated further.

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INPP4B promotes PI3Kα-dependent late endosome formation and Wnt/β-catenin signaling in breast cancer

Nature Communications ◽

10.1038/s41467-021-23241-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Samuel J. Rodgers ◽

Lisa M. Ooms ◽

Viola M. J. Oorschot ◽

Ralf B. Schittenhelm ◽

Elizabeth V. Nguyen ◽

...

Keyword(s):

Breast Cancer ◽

Tumor Growth ◽

Breast Cancer Cells ◽

Triple Negative ◽

Akt Signaling ◽

Late Endosome ◽

Breast Cancers ◽

Lysosomal Degradation ◽

Late Endosomes ◽

Mrna And Protein Expression

AbstractINPP4B suppresses PI3K/AKT signaling by converting PI(3,4)P2 to PI(3)P and INPP4B inactivation is common in triple-negative breast cancer. Paradoxically, INPP4B is also a reported oncogene in other cancers. How these opposing INPP4B roles relate to PI3K regulation is unclear. We report PIK3CA-mutant ER+ breast cancers exhibit increased INPP4B mRNA and protein expression and INPP4B increased the proliferation and tumor growth of PIK3CA-mutant ER+ breast cancer cells, despite suppression of AKT signaling. We used integrated proteomics, transcriptomics and imaging to demonstrate INPP4B localized to late endosomes via interaction with Rab7, which increased endosomal PI3Kα-dependent PI(3,4)P2 to PI(3)P conversion, late endosome/lysosome number and cargo trafficking, resulting in enhanced GSK3β lysosomal degradation and activation of Wnt/β-catenin signaling. Mechanistically, Wnt inhibition or depletion of the PI(3)P-effector, Hrs, reduced INPP4B-mediated cell proliferation and tumor growth. Therefore, INPP4B facilitates PI3Kα crosstalk with Wnt signaling in ER+ breast cancer via PI(3,4)P2 to PI(3)P conversion on late endosomes, suggesting these tumors may be targeted with combined PI3K and Wnt/β-catenin therapies.

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The mitotic checkpoint is a targetable vulnerability of carboplatin-resistant triple negative breast cancers

Scientific Reports ◽

10.1038/s41598-021-82780-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Stijn Moens ◽

Peihua Zhao ◽

Maria Francesca Baietti ◽

Oliviero Marinelli ◽

Delphi Van Haver ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative ◽

Breast Cancer Subtype ◽

Mitotic Checkpoint ◽

Breast Cancers ◽

Checkpoint Kinases ◽

Xenograft Models ◽

Potential Strategy ◽

Shrna Screen ◽

Resistant Cells

AbstractTriple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, lacking effective therapy. Many TNBCs show remarkable response to carboplatin-based chemotherapy, but often develop resistance over time. With increasing use of carboplatin in the clinic, there is a pressing need to identify vulnerabilities of carboplatin-resistant tumors. In this study, we generated carboplatin-resistant TNBC MDA-MB-468 cell line and patient derived TNBC xenograft models. Mass spectrometry-based proteome profiling demonstrated that carboplatin resistance in TNBC is linked to drastic metabolism rewiring and upregulation of anti-oxidative response that supports cell replication by maintaining low levels of DNA damage in the presence of carboplatin. Carboplatin-resistant cells also exhibited dysregulation of the mitotic checkpoint. A kinome shRNA screen revealed that carboplatin-resistant cells are vulnerable to the depletion of the mitotic checkpoint regulators, whereas the checkpoint kinases CHEK1 and WEE1 are indispensable for the survival of carboplatin-resistant cells in the presence of carboplatin. We confirmed that pharmacological inhibition of CHEK1 by prexasertib in the presence of carboplatin is well tolerated by mice and suppresses the growth of carboplatin-resistant TNBC xenografts. Thus, abrogation of the mitotic checkpoint by CHEK1 inhibition re-sensitizes carboplatin-resistant TNBCs to carboplatin and represents a potential strategy for the treatment of carboplatin-resistant TNBCs.

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Clinical CYP2D6 Genotyping to Personalize Adjuvant Tamoxifen Treatment in ER-Positive Breast Cancer Patients: Current Status of a Controversy

Cancers ◽

10.3390/cancers13040771 ◽

2021 ◽

Vol 13 (4) ◽

pp. 771

Author(s):

Tessa A. M. Mulder ◽

Mirjam de With ◽

Marzia del Re ◽

Romano Danesi ◽

Ron H. J. Mathijssen ◽

...

Keyword(s):

Breast Cancer ◽

Clinical Outcome ◽

Cancer Patients ◽

Plasma Concentrations ◽

Tamoxifen Treatment ◽

Current Status ◽

Endocrine Treatment ◽

Breast Cancer Patients ◽

Er Positive ◽

Positive Breast Cancer

Tamoxifen is a major option for adjuvant endocrine treatment in estrogen receptor (ER) positive breast cancer patients. The conversion of the prodrug tamoxifen into the most active metabolite endoxifen is mainly catalyzed by the enzyme cytochrome P450 2D6 (CYP2D6). Genetic variation in the CYP2D6 gene leads to altered enzyme activity, which influences endoxifen formation and thereby potentially therapy outcome. The association between genetically compromised CYP2D6 activity and low endoxifen plasma concentrations is generally accepted, and it was shown that tamoxifen dose increments in compromised patients resulted in higher endoxifen concentrations. However, the correlation between CYP2D6 genotype and clinical outcome is still under debate. This has led to genotype-based tamoxifen dosing recommendations by the Clinical Pharmacogenetic Implementation Consortium (CPIC) in 2018, whereas in 2019, the European Society of Medical Oncology (ESMO) discouraged the use of CYP2D6 genotyping in clinical practice for tamoxifen therapy. This paper describes the latest developments on CYP2D6 genotyping in relation to endoxifen plasma concentrations and tamoxifen-related clinical outcome. Therefore, we focused on Pharmacogenetic publications from 2018 (CPIC publication) to 2021 in order to shed a light on the current status of this debate.

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Triple negative aggressive phenotype controlled by miR-135b and miR-365: new theranostics candidates

Scientific Reports ◽

10.1038/s41598-021-85746-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Gloria Bertoli ◽

Claudia Cava ◽

Fabio Corsi ◽

Francesca Piccotti ◽

Cristina Martelli ◽

...

Keyword(s):

Breast Cancer ◽

Cell Lines ◽

Triple Negative ◽

Differentially Expressed ◽

Tumor Control ◽

Breast Cancers ◽

Basal Breast Cancer ◽

Therapeutic Molecules ◽

Invasive Capacity ◽

Tnbc Subtype

AbstractTriple negative breast cancer (TNBC) accounts for about a fifth of all breast cancers and includes a diverse group of cancers. The heterogeneity of TNBC and the lack of target receptors on the cell surface make it difficult to develop specific therapeutic treatments. These aspects cause the high negative prognosis of patients with this type of tumor. The analysis of the molecular profiles of TNBC samples has allowed a better characterization of this tumor, supporting the search for new reliable diagnostic markers. To this end, we have developed a bioinformatic approach to integrate networks of genes differentially expressed in basal breast cancer compared to healthy tissues, with miRNAs able to regulate their expression. We studied the role of these miRNAs in TNBC subtype cell lines. We therefore identified two miRNAs, namely miR-135b and miR-365, with a central role in regulating the altered functional pathways in basal breast cancer. These two miRNAs are differentially expressed in human TNBC immunohistochemistry-selected tissues, and their modulation has been shown to play a role in the proliferation of tumor control and its migratory and invasive capacity in TNBC subtype cell lines. From the perspective of personalized medicine, we managed to modulate the expression of the two miRNAs in organotypic cultures, suggesting their possible use as diagnostic and therapeutic molecules. miR-135b and miR-365 have a key role in TNBC, controlling proliferation and invasion. Their detection could be helpful in TNBC diagnosis, while their modulation could become a new therapeutic tool for TNBC.

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Repositioning metformin and propranolol for colorectal and triple negative breast cancers treatment

Scientific Reports ◽

10.1038/s41598-021-87525-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

L. E. Anselmino ◽

M. V. Baglioni ◽

F. Malizia ◽

N. Cesatti Laluce ◽

C. Borini Etichetti ◽

...

Keyword(s):

Breast Cancer ◽

Side Effects ◽

Triple Negative ◽

Epithelial Mesenchymal Transition ◽

Drug Repositioning ◽

Combined Treatment ◽

Alternative Therapy ◽

Breast Cancers ◽

Mesenchymal Transition ◽

Tumor Types

AbstractDrug repositioning refers to new uses for existing drugs outside the scope of the original medical indications. This approach fastens the process of drug development allowing finding effective drugs with reduced side effects and lower costs. Colorectal cancer (CRC) is often diagnosed at advanced stages, when the probability of chemotherapy resistance is higher. Triple negative breast cancer (TNBC) is the most aggressive type of breast cancer, highly metastatic and difficult to treat. For both tumor types, available treatments are generally associated to severe side effects. In our work, we explored the effect of combining metformin and propranolol, two repositioned drugs, in both tumor types. We demonstrate that treatment affects viability, epithelial-mesenchymal transition and migratory potential of CRC cells as we described before for TNBC. We show that combined treatment affects different steps leading to metastasis in TNBC. Moreover, combined treatment is also effective preventing the development of 5-FU resistant CRC. Our data suggest that combination of metformin and propranolol could be useful as a putative adjuvant treatment for both TNBC and CRC and an alternative for chemo-resistant CRC, providing a low-cost alternative therapy without associated toxicity.

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The Roles of DNA Demethylases in Triple-Negative Breast Cancer

Pharmaceuticals ◽

10.3390/ph14070628 ◽

2021 ◽

Vol 14 (7) ◽

pp. 628

Author(s):

Shoghag Panjarian ◽

Jean-Pierre J. Issa

Keyword(s):

Breast Cancer ◽

Dna Methylation ◽

Tumor Suppressor Genes ◽

Hormone Receptors ◽

Triple Negative ◽

Breast Cancers ◽

Therapeutic Implications ◽

High Propensity ◽

Dna Methylation Profile

Triple-negative breast cancers (TNBCs) are very heterogenous, molecularly diverse, and are characterized by a high propensity to relapse or metastasize. Clinically, TNBC remains a diagnosis of exclusion by the lack of hormone receptors (Estrogen Receptor (ER) and Progesterone Receptor (PR)) as well as the absence of overexpression and/or amplification of HER2. DNA methylation plays an important role in breast cancer carcinogenesis and TNBCs have a distinct DNA methylation profile characterized by marked hypomethylation and lower gains of methylations compared to all other subtypes. DNA methylation is regulated by the balance of DNA methylases (DNMTs) and DNA demethylases (TETs). Here, we review the roles of TETs as context-dependent tumor-suppressor genes and/or oncogenes in solid tumors, and we discuss the current understandings of the oncogenic role of TET1 and its therapeutic implications in TNBCs.

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TrkA Interacts with and Phosphorylates STAT3 to Enhance Gene Transcription and Promote Breast Cancer Stem Cells in Triple-Negative and HER2-Enriched Breast Cancers

Cancers ◽

10.3390/cancers13102340 ◽

2021 ◽

Vol 13 (10) ◽

pp. 2340

Author(s):

Angelina T. Regua ◽

Noah R. Aguayo ◽

Sara Abu Jalboush ◽

Daniel L. Doheny ◽

Sara G. Manore ◽

...

Keyword(s):

Breast Cancer ◽

Stem Cells ◽

Cancer Stem Cells ◽

Gene Transcription ◽

Target Genes ◽

Triple Negative ◽

Breast Cancer Stem Cells ◽

Breast Cancers ◽

Co Activation ◽

Stat3 Phosphorylation

JAK2–STAT3 and TrkA signaling pathways have been separately implicated in aggressive breast cancers; however, whether they are co-activated or undergo functional interaction has not been thoroughly investigated. Herein we report, for the first time that STAT3 and TrkA are significantly co-overexpressed and co-activated in triple-negative breast cancer (TNBC) and HER2-enriched breast cancer, as shown by immunohistochemical staining and data mining. Through immunofluorescence staining–confocal microscopy and immunoprecipitation–Western blotting, we found that TrkA and STAT3 co-localize and physically interact in the cytoplasm, and the interaction is dependent on STAT3-Y705 phosphorylation. TrkA–STAT3 interaction leads to STAT3 phosphorylation at Y705 by TrkA in breast cancer cells and cell-free kinase assays, indicating that STAT3 is a novel substrate of TrkA. β-NGF-mediated TrkA activation induces TrkA–STAT3 interaction, STAT3 nuclear transport and transcriptional activity, and the expression of STAT3 target genes, SOX2 and MYC. The co-activation of both pathways promotes breast cancer stem cells. Finally, we found that TNBC and HER2-enriched breast cancer with JAK2–STAT3 and TrkA co-activation are positively associated with poor overall metastasis-free and organ-specific metastasis-free survival. Collectively, our study uncovered that TrkA is a novel activating kinase of STAT3, and their co-activation enhances gene transcription and promotes breast cancer stem cells in TNBC and HER2-enriched breast cancer.

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Relationship Between Plasma Estradiol Levels and Estrogen-Responsive Gene Expression in Estrogen Receptor–Positive Breast Cancer in Postmenopausal Women

Journal of Clinical Oncology ◽

10.1200/jco.2009.23.9616 ◽

2010 ◽

Vol 28 (7) ◽

pp. 1161-1167 ◽

Cited By ~ 75

Author(s):

Anita K. Dunbier ◽

Helen Anderson ◽

Zara Ghazoui ◽

Elizabeth J. Folkerd ◽

Roger A'Hern ◽

...

Keyword(s):

Breast Cancer ◽

Gene Expression ◽

Estrogen Receptor ◽

Postmenopausal Women ◽

Multivariable Analysis ◽

Independent Set ◽

Breast Cancers ◽

Plasma Estradiol ◽

Er Positive ◽

Positive Breast Cancer

Purpose To determine whether plasma estradiol (E2) levels are related to gene expression in estrogen receptor (ER)–positive breast cancers in postmenopausal women. Materials and Methods Genome-wide RNA profiles were obtained from pretreatment core-cut tumor biopsies from 104 postmenopausal patients with primary ER-positive breast cancer treated with neoadjuvant anastrozole. Pretreatment plasma E2 levels were determined by highly sensitive radioimmunoassay. Genes were identified for which expression was correlated with pretreatment plasma E2 levels. Validation was performed in an independent set of 73 ER-positive breast cancers. Results The expression of many known estrogen-responsive genes and gene sets was highly significantly associated with plasma E2 levels (eg, TFF1/pS2, GREB1, PDZK1 and PGR; P < .005). Plasma E2 explained 27% of the average expression of these four average estrogen-responsive genes (ie, AvERG; r = 0.51; P < .0001), and a standardized mean of plasma E2 levels and ER transcript levels explained 37% (r, 0.61). These observations were validated in an independent set of 73 ER-positive tumors. Exploratory analysis suggested that addition of the nuclear coregulators in a multivariable analysis with ER and E2 levels might additionally improve the relationship with the AvERG. Plasma E2 and the standardized mean of E2 and ER were both significantly correlated with 2-week Ki67, a surrogate marker of clinical outcome (r = −0.179; P = .05; and r = −0.389; P = .0005, respectively). Conclusion Plasma E2 levels are significantly associated with gene expression of ER-positive breast cancers and should be considered in future genomic studies of ER-positive breast cancer. The AvERG is a new experimental tool for the study of putative estrogenic stimuli of breast cancer.

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