scholarly journals Modulation of Early Mitotic Inhibitor 1 (EMI1) Depletion on the Sensitivity of PARP Inhibitors in BRCA1 Mutated Triple-Negative Breast Cancer Cells

2020 ◽  
Author(s):  
Dina Moustafa ◽  
Maha R. Abd Elwahed ◽  
Hanaa H. Elsaid ◽  
Jeffrey D. Parvin
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Cytotoxic Drugs ◽  
Breast Cancers ◽  
Cell Viability Assay ◽  
Rad51 Protein ◽  
Chemotherapy Drugs ◽  
Chk1 Inhibitor

AbstractTriple negative breast cancer (TNBC) represents approximately 10–15% of all breast cancers and has a poor outcome as it lacks a receptor target for therapy, and TNBC is frequently associated with a germline mutation of BRCA1. Poly (ADP-ribose) polymerase inhibitor (PARPi) drugs have demonstrated some effectiveness in treating BRCA1 or BRCA2 mutated breast and ovarian cancers but resistance to PARPi is common. Published results found that resistance to Olaparib, a PARPi, can be due to downregulation of EMI1 and the consequent upregulation of the RAD51 recombinase. Using a tissue culture-based cell viability assay, we extended those observations to another PARPi and to other chemotherapy drugs that affect DNA repair or the cell cycle. As we expected, EMI1 downregulation resulted in resistance to another PARPi drug, Talazoparib. EMI1 downregulation also led to resistance to other cytotoxic drugs, Cisplatin and CHK1 inhibitor. Surprisingly, EMI1 depletion also led to resistance to a MEK inhibitor, though this inhibitor blocks cells in G1 phase of the cell cycle and would not be expected to be sensitive to EMI1 levels. Notably, increasing the RAD51 protein expression only partially recapitulated the effects of EMI1 depletion in causing resistance to different PARPi and the other cytotoxic drugs. These results suggest that the downstream effects of EMI1 downregulation that contribute to PARPi resistance are increasing the concentration of RAD51 protein in the cell and blocking mitotic entry. We found that combining CHK1 inhibitor with olaparib results in restoration of sensitivity even when EMI1 expression is downregulated. This combination therapy may be a means to overcome the PARPi resistance in BRCA1-deficient TNBC cells.

scholarly journals Modulation of Early Mitotic Inhibitor 1 (EMI1) depletion on the sensitivity of PARP inhibitors in BRCA1 mutated triple-negative breast cancer cells

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0235025
Author(s):  
Dina Moustafa ◽  
Maha R. Abd Elwahed ◽  
Hanaa H. Elsaid ◽  
Jeffrey D. Parvin
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Parp Inhibitors ◽  
Cytotoxic Drugs ◽  
Breast Cancers ◽  
Cell Viability Assay ◽  
Rad51 Protein ◽  
Chemotherapy Drugs ◽  
Chk1 Inhibitor

Triple negative breast cancer (TNBC) represents approximately 10–15% of all breast cancers and has a poor outcome as it lacks a receptor target for therapy, and TNBC is frequently associated with a germline mutation of BRCA1. Poly (ADP-ribose) polymerase inhibitor (PARPi) drugs have demonstrated some effectiveness in treating BRCA1 or BRCA2 mutated breast and ovarian cancers but resistance to PARPi is common. Published results found that resistance to Olaparib, a PARPi, can be due to downregulation of EMI1 and the consequent upregulation of the RAD51 recombinase. Using a tissue culture-based cell viability assay, we extended those observations to another PARPi and to other chemotherapy drugs that affect DNA repair or the cell cycle. As we expected, EMI1 downregulation resulted in resistance to another PARPi drug, Talazoparib. EMI1 downregulation also led to resistance to other cytotoxic drugs, Cisplatin and CHK1 inhibitor. Notably, increasing the RAD51 protein expression only recapitulated some, but not all, of the effects of EMI1 depletion in conferring to the cell resistance to different PARPi and the other cytotoxic drugs. These results suggest that the downstream effects of EMI1 downregulation that contribute to PARPi resistance are increasing the concentration of RAD51 protein in the cell and blocking mitotic entry. We found that combining CHK1 inhibitor with olaparib results in restoration of sensitivity even when EMI1 expression is downregulated. This combination therapy may be a means to overcome the PARPi resistance in BRCA1-deficient TNBC cells.

scholarly journals CHFR regulates chemoresistance in triple-negative breast cancer through destabilizing ZEB1

2021 ◽  
Vol 12 (9) ◽  
Author(s):  
Hong Luo ◽  
Zhicheng Zhou ◽  
Shan Huang ◽  
Mengru Ma ◽  
Manyu Zhao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Triple Negative Breast Cancer ◽  
Fatty Acid Synthase ◽  
Triple Negative ◽  
Trichostatin A ◽  
Affinity Purification ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Breast Cancers

AbstractFailures to treat triple-negative breast cancer (TNBC) are mainly due to chemoresistance or radioresistance. We and others previously discovered that zinc finger E-box-binding homeobox 1 (ZEB1) is a massive driver causing these resistance. However, how to dynamically modulate the intrinsic expression of ZEB1 during cell cycle progression is elusive. Here integrated affinity purification combined with mass spectrometry and TCGA analysis identify a cell cycle-related E3 ubiquitin ligase, checkpoint with forkhead and ring finger domains (CHFR), as a key negative regulator of ZEB1 in TNBC. Functional studies reveal that CHFR associates with and decreases ZEB1 expression in a ubiquitinating-dependent manner and that CHFR represses fatty acid synthase (FASN) expression through ZEB1, leading to significant cell death of TNBC under chemotherapy. Intriguingly, a small-molecule inhibitor of HDAC under clinical trial, Trichostatin A (TSA), increases the expression of CHFR independent of histone acetylation, thereby destabilizes ZEB1 and sensitizes the resistant TNBC cells to conventional chemotherapy. In patients with basal-like breast cancers, CHFR levels significantly correlates with survival. These findings suggest the therapeutic potential for targeting CHFR-ZEB1 signaling in resistant malignant breast cancers.

scholarly journals Current and emerging treatment options in triple-negative breast cancer

2011 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Omer Dizdar ◽  
Kadri Altundag
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Histological Grade ◽  
Treatment Options ◽  
Growth Factor Receptor ◽  
Immunohistochemical Analysis ◽  
Endocrine Treatment ◽  
Breast Cancers ◽  
Chemotherapy Drugs

Triple-negative breast cancer is defined by the lack of estrogen receptor, progesterone receptor and HER2 expression with immunohistochemical analysis. Triplenegative breast cancers are poorly differentiated, characterized by high histological grade and occur at a younger age. Treatment options are limited as these tumors are naturally resistant to existing targeted therapies, i.e., endocrine treatment and trastuzumab. An improved understanding of the biology of TNBC has led to evaluation of DNA-damaging chemotherapy drugs and targeted agents, including poly (ADP-ribose) polymerase inhibitors, epidermal growth factor receptor inhibitors, angiogenesis inhibitors, etc., in the treatment of TNBC. This review focuses on outlining the current and emerging treatment options in patients with triple-negative breast cancer.

scholarly journals MYBL1 Knockdown in a Triple Negative Breast Cancer Line: Evidence of Down-Regulation of MYBL2, TCF19 and KIF18b Expression

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Player A ◽  
◽  
Abraham N ◽  
Abdulrahman N ◽  
Nsende E ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Cell Cycle ◽  
Cell Line ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Gene Expression Omnibus ◽  
Breast Cancers ◽  
Down Regulation ◽  
Cell Cycle Signaling

Purpose: The MYBL1 gene is a strong transcriptional activator, associated with cell cycle signaling and differentiation. Data show the gene is overexpressed in triple negative breast cancers. Considering the possibility that MYBL1 might be involved in events associated with the pathogenesis of these cancers, we sought to identify genes associated with MYBL1 expression in triple negative breast cancer. Methods: shRNA lentiviral knockdown was used to down-regulate the MYBL1 gene. Microarray analyses were used to identify genes either directly or indirectly affected by targeting MYBL1 knockdown. Data analyses was performed utilizing Affymetrix TAC 4.0, Chip X transcription factor analyses, Target Scan miRNA analyses, and STRING analyses was used to determine protein: protein interaction and pathway analyses. Web Gestalt and Gene Ontology were used to determine pathway and gene-set enrichments. Publicly available patient and cell line datasets were retrieved and processed using resources available in Gene Expression Omnibus and Oncomine. The polymerase chain reaction and western analyses were used to determine transcript and protein levels, respectively. Results: Knockdown of MYBL1 in a triple negative breast cell line led to down-regulation of MYBL2, TCF19, KIF18b along with an enrichment of cell cycle signaling genes. Gene expression analyses show that MYBL1, MYBL2, TCF19 and KIF18b display a similar pattern of expression in breast cell lines and many of the archival patient datasets examined. Conclusion: TNBC is a heterogeneous subtype, so these data suggest that cancers that over-express MYBL1, express MYBL2, TCF19 and KIF18b. Bioinformatic analyses suggest MYBL1 regulates MYBL2 which leads to regulation of TCF19 and KIF18b.

scholarly journals Current and emerging treatment options in triple-negative breast cancer

2011 ◽  
pp. 5-13
Author(s):  
Omer Dizdar ◽  
Kadri Altundag
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Histological Grade ◽  
Treatment Options ◽  
Growth Factor Receptor ◽  
Immunohistochemical Analysis ◽  
Endocrine Treatment ◽  
Breast Cancers ◽  
Chemotherapy Drugs

Triple-negative breast cancer is defined by the lack of estrogen receptor, progesterone receptor and HER2 expression with immunohistochemical analysis. Triplenegative breast cancers are poorly differentiated, characterized by high histological grade and occur at a younger age. Treatment options are limited as these tumors are naturally resistant to existing targeted therapies, i.e., endocrine treatment and trastuzumab. An improved understanding of the biology of TNBC has led to evaluation of DNA-damaging chemotherapy drugs and targeted agents, including poly (ADP-ribose) polymerase inhibitors, epidermal growth factor receptor inhibitors, angiogenesis inhibitors, etc., in the treatment of TNBC. This review focuses on outlining the current and emerging treatment options in patients with triple-negative breast cancer.

Improving the efficacy of chemotherapy drugs for the treatment of triple-negative breast cancers.

2012 ◽  
Vol 30 (27_suppl) ◽  
pp. 107-107
Author(s):  
Behyar Zoghi ◽  
Peter Ravdin
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
High Throughput ◽  
Triple Negative Breast Cancer ◽  
Breast Cancer Cells ◽  
Triple Negative ◽  
Expression Profiles ◽  
Breast Cancers ◽  
Efficient Treatment ◽  
Chemotherapy Drugs

107 Background: Approximately 15-20% of all breast cancers account for triple-negative breast cancers that exhibit aggressive, distinct metastatic pattern and poor prognosis. More than 50% of patients with triple negative breast cancers develop chemoresistance and do not respond to chemotherapeutic drugs, leading to early relapse and shorter survival. Understanding the mechanisms underlying such resistance is therefore crucial for the development of new, efficacious cancer drugs. Methods: Through high-throughput miRNA inhibitor library screens, we have identified miRNA inhibitors that sensitize resistant triple negative breast cancer cells to paclitaxel, a drug commonly used to treat triple negative breast cancers. Results: Through high-throughput miRNA inhibitor library screens, we have identified miRNA inhibitors that sensitize resistant triple negative breast cancer cells to paclitaxel, a drug commonly used to treat triple negative breast cancers. Since miRNAs are endogenously expressed and can be easily manipulated using synthetic oligoribonucleotides, we believe that they represent more attractive targets than the single gene or gene product that is the target of conventional cancer treatments that are typically prone to drug resistance. Supporting this, we have recently demonstrated that miRNAs can be systemically delivered to treat breast cancer lung metastasis without any hepatotoxicity. In addition to being a potent therapeutic regimen, our preliminary analyses reveal that miRNAs can be bonafide early prognostic markers to monitor treatment response to specific drugs in triple-negative breast cancers. Conclusions: Taken together, these findings suggest that miRNA can serve as potent therapeutic adjuvants and although the data content of miRNA profiles is far less than that of gene expression profiles, by virtue of their ability to modulate entire spectrum of genes and pathways miRNAs have potential to be better classifiers for the prognosis and response to treatment of cancers. We believe that the identification of miRNAs that mediate chemoresistance could lead to more efficient treatment selection at the patient level and an improved response rates at the population level.

scholarly journals The Anticancer Effects of Flavonoids through miRNAs Modulations in Triple-Negative Breast Cancer

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1212
Author(s):  
Getinet M. Adinew ◽  
Equar Taka ◽  
Patricia Mendonca ◽  
Samia S. Messeha ◽  
Karam F. A. Soliman
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Progression ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Therapeutic Potential ◽  
Biological Activities ◽  
Therapeutic Option ◽  
Mesenchymal Transition ◽  
Anticancer Effects

Triple- negative breast cancer (TNBC) incidence rate has regularly risen over the last decades and is expected to increase in the future. Finding novel treatment options with minimum or no toxicity is of great importance in treating or preventing TNBC. Flavonoids are new attractive molecules that might fulfill this promising therapeutic option. Flavonoids have shown many biological activities, including antioxidant, anti-inflammatory, and anticancer effects. In addition to their anticancer effects by arresting the cell cycle, inducing apoptosis, and suppressing cancer cell proliferation, flavonoids can modulate non-coding microRNAs (miRNAs) function. Several preclinical and epidemiological studies indicate the possible therapeutic potential of these compounds. Flavonoids display a unique ability to change miRNAs’ levels via different mechanisms, either by suppressing oncogenic miRNAs or activating oncosuppressor miRNAs or affecting transcriptional, epigenetic miRNA processing in TNBC. Flavonoids are not only involved in the regulation of miRNA-mediated cancer initiation, growth, proliferation, differentiation, invasion, metastasis, and epithelial-to-mesenchymal transition (EMT), but also control miRNAs-mediated biological processes that significantly impact TNBC, such as cell cycle, immune system, mitochondrial dysregulation, modulating signaling pathways, inflammation, and angiogenesis. In this review, we highlighted the role of miRNAs in TNBC cancer progression and the effect of flavonoids on miRNA regulation, emphasizing their anticipated role in the prevention and treatment of TNBC.

scholarly journals Triple-Negative Breast Cancer: Adjuvant Therapeutic Options

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Ayca Gucalp ◽  
Tiffany A. Traina
Keyword(s):  
Breast Cancer ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Growth Factor Receptor ◽  
Progesterone Receptors ◽  
Cytotoxic Chemotherapy ◽  
Breast Cancers ◽  
Targeted Agents ◽  
Increased Risk ◽  
Disproportionate Number

Triple-negative breast cancer (TNBC), a subtype distinguished by negative immunohistochemical assays for expression of the estrogen and progesterone receptors (ER/PR) and human epidermal growth factor receptor-2(HER2) represents 15% of all breast cancers. Patients with TNBC generally experience a more aggressive clinical course with increased risk of disease progression and poorer overall survival. Furthermore, this subtype accounts for a disproportionate number of disease-related mortality in part due to its aggressive natural history and our lack of effective targeted agents beyond conventional cytotoxic chemotherapy. In this paper, we will review the epidemiology, risk factors, prognosis, and the molecular and clinicopathologic features that distinguish TNBC from other subtypes of breast cancer. In addition, we will examine the available data for the use of cytotoxic chemotherapy in the treatment of TNBC in both the neoadjuvant and adjuvant setting and explore the ongoing development of newer targeted agents.

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