scholarly journals Killing the second messenger: targeting loss of cell cycle control in endocrine-resistant breast cancer

2011 ◽  
Vol 18 (4) ◽  
pp. C19-C24 ◽  
Author(s):  
Carol A Lange ◽  
Douglas Yee
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Control ◽  
Endocrine Resistance ◽  
Cell Cycle Checkpoint ◽  
Regulatory Subunit ◽  
Breast Cancers ◽  
Checkpoint Control ◽  
Estrogen Synthesis

The majority (∼70%) of breast cancers are steroid hormone receptor (SR) positive at the time of diagnosis. Endocrine therapies that target estrogen receptor α (ERα) action (tamoxifen, toremifene, fulvestrant) or estrogen synthesis (aromatase inhibitors: letrozole, anastrozole, exemestane; or ovarian suppression) are a clinical mainstay. However, up to 50% of SR+ breast cancers exhibit de novo or acquired resistance to these clinical interventions. Mechanisms of resistance to endocrine therapies often include upregulation and/or activation of signal transduction pathways that input to cell cycle regulation. Cyclin D1, the regulatory subunit of cyclin-dependent protein kinases four and six (CDK4/6) serves as a convergence point for multiple signaling pathways. In a recent paper entitled ‘Therapeutically Activating Retinoblastoma (RB): Reestablishing Cell Cycle Control in Endocrine Therapy-Resistant Breast Cancer’, Thangavel et al. reported maintenance of cyclin D1 expression and RB phosphorylation in the face of ER ablation in multiple breast cancer cell line models of endocrine resistance. RB-dysfunction defined a unique gene signature that was associated with luminal B-type breast cancer and predictive of poor response to endocrine therapies. Notably, a new CDK4/6 inhibitor (PD-0332991) was capable of inducing growth arrest by a mechanism that was most consistent with cellular senescence. In this review, these findings are discussed in the context of SRs as important mediators of cell cycle progression, and the frequent loss of cell cycle checkpoint control that typifies breast cancer progression. These studies provide renewed hope of effectively stabilizing endocrine-resistant breast cancers using available complementary (to endocrine-based therapies) cytostatic agents in the form of CDK4/6 inhibitors.

scholarly journals Progress with palbociclib in breast cancer: latest evidence and clinical considerations

2016 ◽  
Vol 9 (2) ◽  
pp. 83-105 ◽  
Author(s):  
Andrea Rocca ◽  
Alessio Schirone ◽  
Roberta Maltoni ◽  
Sara Bravaccini ◽  
Lorenzo Cecconetto ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Randomized Clinical Trials ◽  
Cell Cycle Control ◽  
Endocrine Resistance ◽  
Cyclin D ◽  
Breast Cancers ◽  
Her2 Positive ◽  
Cycle Progression

Deregulation of the cell cycle is a hallmark of cancer, and research on cell cycle control has allowed identification of potential targets for anticancer treatment. Palbociclib is a selective inhibitor of the cyclin-dependent kinases 4 and 6 (CDK4/6), which are involved, with their coregulatory partners cyclin D, in the G1-S transition. Inhibition of this step halts cell cycle progression in cells in which the involved pathway, including the retinoblastoma protein (Rb) and the E2F family of transcription factors, is functioning, although having been deregulated. Among breast cancers, those with functioning cyclin D-CDK4/6-Rb-E2F are mainly hormone-receptor (HR) positive, with some HER2-positive and rare triple-negative cases. Deregulation results from genetic or otherwise occurring hyperactivation of molecules subtending cell cycle progression, or inactivation of cell cycle inhibitors. Based on results of randomized clinical trials, palbociclib was granted accelerated approval by the US Food and Drug Administration (FDA) for use in combination with letrozole as initial endocrine-based therapy for metastatic disease in postmenopausal women with HR-positive, HER2-negative breast cancer, and was approved for use in combination with fulvestrant in women with HR-positive, HER2-negative advanced breast cancer with disease progression following endocrine therapy. This review provides an update of the available knowledge on the cell cycle and its regulation, on the alterations in cyclin D-CDK4/6-Rb-E2F axis in breast cancer and their roles in endocrine resistance, on the preclinical activity of CDK4/6 inhibitors in breast cancer, both as monotherapy and as partners of combinatorial synergic treatments, and on the clinical development of palbociclib in breast cancer.

Alterations in the cell cycle checkpoint pathway in breast cancer.

2015 ◽  
Vol 33 (28_suppl) ◽  
pp. 126-126
Author(s):  
Gargi Dan Basu ◽  
Tracey White ◽  
Janine R LoBello ◽  
Ahmet Kurdoglu ◽  
Subha Krishnan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cyclin D1 ◽  
Exome Sequencing ◽  
Genetic Alterations ◽  
Cell Cycle Checkpoint ◽  
Her2 Status ◽  
Her2 Positive ◽  
Cell Cycle Pathway ◽  
Tnbc Subtype

126 Background: Breast cancer is a molecularly diverse disease with molecular subtypes defined by ER, PR and HER2 status. Dysregulation of the cell cycle pathway through activation of cyclin D1 and/or inactivation of CDKN2A is a mechanism of tumor progression in breast cancer and drugs targeting CDK4/6 is undergoing investigation in this disease with promising preliminary results. We investigated several key genetic alterations in cell cycle regulatory proteins in advanced breast cancer patient samples to identify potential targets for cell cycle related treatment options. Methods: A comprehensive genomic profiling was performed on 37 breast cancer samples with the majority being metastatic. Testing included targeted exome sequencing of 562 genes in tumor and paired normal DNA. Results: Patients’ ages ranged from 27-66 years. Analysis of cell cycle regulatory genes revealed focal amplification of cyclin D1/D2 or CDKN2A loss in 9/37 (24%) of cases, of which, 45% were hormone receptor (HR) positive, HER2 negative, 33% were HR positive, HER2 positive and 22% were triple negative (TNBC) subtype. Loss of RB1 was analyzed since it negatively regulates response to CDK4/6 inhibitors. Loss of RB1 was noted in 4/37 (10.8%) of cases, all of which were TNBCs. Only a single TNBC with RB1 loss had concurrent CDK4 amplification and loss of CDKN2A. No evidence of CCNE1 amplification was found in any samples. Incidence of CDK4 and CDK6 amplification was found in samples with cyclin D1 amplification or CDKN2A loss. Our cohort included a single male TNBC patient who harbored cyclin D1 amplification as well as CDKN2A loss. Overall, amplification of cyclin D1, cyclin D2, CDK4 and CDK6 was found in 16%, 5.4%, 2.7% and 2.7% respectively. Loss of CDKN2A was noted in 5.4% of tumors profiled. Conclusions: Exome sequencing identified subsets of patients with mutated cell cycle associated genes that may benefit from CDK 4/6 inhibitors. Our data suggests loss of RB1 is more frequent in TNBC subtype which may confer resistance to CDK4/6 inhibitors. Our analysis suggests that in addition to HR positive, HER2 negative patients, a subset of HR positive, HER2 positive patients could be sensitive to CDK4/6 inhibitors due to activation of the cell cycle pathway as evidenced by mutations in key genes.

scholarly journals Proline rich 11 (PRR11) overexpression amplifies PI3K signaling and promotes antiestrogen resistance in breast cancer

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kyung-min Lee ◽  
Angel L. Guerrero-Zotano ◽  
Alberto Servetto ◽  
Dhivya R. Sudhan ◽  
Chang-Ching Lin ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Cells ◽  
Endocrine Resistance ◽  
Poor Response ◽  
Regulatory Subunit ◽  
Antiestrogen Resistance ◽  
Breast Cancers ◽  
Pi3k Inhibitors ◽  
Highly Sensitive ◽  
Causal Genes

Abstract The 17q23 amplicon is associated with poor outcome in ER+ breast cancers, but the causal genes to endocrine resistance in this amplicon are unclear. Here, we interrogate transcriptome data from primary breast tumors and find that among genes in 17q23, PRR11 is a key gene associated with a poor response to therapeutic estrogen suppression. PRR11 promotes estrogen-independent proliferation and confers endocrine resistance in ER+ breast cancers. Mechanistically, the proline-rich motif-mediated interaction of PRR11 with the p85α regulatory subunit of PI3K suppresses p85 homodimerization, thus enhancing insulin-stimulated binding of p110-p85α heterodimers to IRS1 and activation of PI3K. PRR11-amplified breast cancer cells rely on PIK3CA and are highly sensitive to PI3K inhibitors, suggesting that PRR11 amplification confers PI3K dependence. Finally, genetic and pharmacological inhibition of PI3K suppresses PRR11-mediated, estrogen-independent growth. These data suggest ER+/PRR11-amplified breast cancers as a novel subgroup of tumors that may benefit from treatment with PI3K inhibitors and antiestrogens.

scholarly journals Significance of Targeting VEGFR-2 and Cyclin D1 in Luminal-A Breast Cancer

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4606
Author(s):  
Ashraf N. Abdalla ◽  
Amal Qattan ◽  
Waleed H. Malki ◽  
Imran Shahid ◽  
Mohammad Akbar Hossain ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cyclin D1 ◽  
New Drugs ◽  
Breast Cancers ◽  
Breast Cancer Patients ◽  
Mcf7 Cells ◽  
Hsp90 Inhibition ◽  
Luminal A

The hormonal luminal-A is the most pre-dominant sub type of breast cancer (BC), and it is associated with a high level of cyclin D1 in Saudi patients. Tamoxifen is the golden therapy for hormonal BC, but resistance of cancer cells to tamoxifen contributes to the recurrence of BC due to many reasons, including high levels of AIB1 and cyclin D1. Overcoming drug resistance could be achieved by exploring alternative targetable therapeutic pathways and new drugs or combinations. The objective of this study was to determine the differentially enriched pathways in 12 samples of Saudi women diagnosed with luminal-A using the PamChip peptide microarray-based kinase activity profiling, and to compare the activity of HAA2020 and dinaciclib with tamoxifen in singles and combinations in the MCF7 luminal-A cell line. Our results of network and pathway analysis of the 12 samples highlighted the importance of VEGFR and CDKs in promoting luminal-A breast cancer. The activation of VEGF signaling via VEGFR-2 leads to activation of PI3K/AKT kinases and an increase of cell survival, and leads to activation of Hsp90, which induces the phosphorylation of FAK1, resulting in cytoskeleton remodeling. PLC-gamma 1 is also activated, leading to FAK-2 and PKC activation. Notably, the G1/S cell cycle phases and phosphorylation processes contribute to the top seven tumorigenesis processes in the 12 samples. Further, the MTT combination of HAA2020 and dinaciclib showed the best combination index (CI), was more clonogenic against MCF7 cells compared to the other combinations, and it also showed the best selectivity index (SI) in normal MRC5 cells. Interestingly, HAA2020 and dinaciclib showed a synergistic apoptotic and G1 cell cycle effect in MCF7 cells, which was supported by their synergistic CDK2, cyclin D1, and PCNA inhibition activities. Additionally, the combination showed VEGFR-2 and Hsp90 inhibition activities in MCF7 cells. The results show the significance of targeting VEGFR-2 and cyclin D1 in Saudi luminal-A breast cancer patients, and the effect of combining HAA2020 and dinaciclib on those targets in the MCF7 model. It also warrants further preclinical and in vivo investigations for the combination of HAA2020 and dinaciclib as a possible future second-line treatment for luminal-A breast cancers.

Downstream targets of growth factor and oestrogen signalling and endocrine resistance: the potential roles of c-Myc, cyclin D1 and cyclin E

2005 ◽  
Vol 12 (Supplement_1) ◽  
pp. S47-S59 ◽  
Author(s):  
Alison J Butt ◽  
Catriona M McNeil ◽  
Elizabeth A Musgrove ◽  
Robert L Sutherland
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Cyclin E ◽  
Endocrine Resistance ◽  
Cycle Progression ◽  
Er Positive ◽  
Oestrogen Signalling

Antioestrogen therapy is a highly effective treatment for patients with oestrogen-receptor (ER)-positive breast cancer, emphasising the central role of oestrogen action in the development and progression of this disease. However, effective antioestrogen treatment is often compromised by acquired endocrine resistance, prompting the need for a greater understanding of the down-stream mediators of oestrogen action that may contribute to this effect. Recent studies have demonstrated a critical link between oestrogen’s mitogenic effects and cell cycle progression, particularly at the G1 to S transition where key effectors of oestrogen action are c-Myc and cyclin D1, which converge on the activation of cyclin E-cdk2. These components are rapidly upregulated in response to oestrogen, and can mimic its actions on cell cycle progression, including re-initiating cell proliferation in antioestrogen-arrested cells. Here we review the roles of c-Myc, cyclin D1 and cyclin E in oestrogen action and endocrine resistance, and identify their potential as markers of disease progression and endocrine responsiveness, and as novel therapeutic targets in endocrine-resistant breast cancer.

scholarly journals Acetylation of MORC2 by NAT10 regulates cell-cycle checkpoint control and resistance to DNA-damaging chemotherapy and radiotherapy in breast cancer

2020 ◽  
Vol 48 (7) ◽  
pp. 3638-3656 ◽  
Author(s):  
Hong-Yi Liu ◽  
Ying-Ying Liu ◽  
Fan Yang ◽  
Lin Zhang ◽  
Fang-Lin Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Dna Damage ◽  
Target Genes ◽  
Cyclin B1 ◽  
Chemotherapeutic Agents ◽  
Cell Cycle Checkpoint ◽  
Checkpoint Control ◽  
G2 Checkpoint ◽  
Cycle Checkpoint

Abstract MORC family CW-type zinc finger 2 (MORC2) is an oncogenic chromatin-remodeling enzyme with an emerging role in DNA repair. Here, we report a novel function for MORC2 in cell-cycle checkpoint control through an acetylation-dependent mechanism. MORC2 is acetylated by the acetyltransferase NAT10 at lysine 767 (K767Ac) and this process is counteracted by the deacetylase SIRT2 under unperturbed conditions. DNA-damaging chemotherapeutic agents and ionizing radiation stimulate MORC2 K767Ac through enhancing the interaction between MORC2 and NAT10. Notably, acetylated MORC2 binds to histone H3 phosphorylation at threonine 11 (H3T11P) and is essential for DNA damage-induced reduction of H3T11P and transcriptional repression of its downstream target genes CDK1 and Cyclin B1, thus contributing to DNA damage-induced G2 checkpoint activation. Chemical inhibition or depletion of NAT10 or expression of an acetylation-defective MORC2 (K767R) forces cells to pass through G2 checkpoint, resulting in hypersensitivity to DNA-damaging agents. Moreover, MORC2 acetylation levels are associated with elevated NAT10 expression in clinical breast tumor samples. Together, these findings uncover a previously unrecognized role for MORC2 in regulating DNA damage-induced G2 checkpoint through NAT10-mediated acetylation and provide a potential therapeutic strategy to sensitize breast cancer cells to DNA-damaging chemotherapy and radiotherapy by targeting NAT10.

scholarly journals MCM3 upregulation confers endocrine resistance in breast cancer and is a predictive marker of diminished tamoxifen benefit

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Sanne Løkkegaard ◽  
Daniel Elias ◽  
Carla L. Alves ◽  
Martin V. Bennetzen ◽  
Anne-Vibeke Lænkholm ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Patients ◽  
Endocrine Therapy ◽  
Endocrine Resistance ◽  
Predictive Marker ◽  
Endocrine Treatment ◽  
Breast Cancer Patients ◽  
Minichromosome Maintenance ◽  
Primary Tumors

AbstractResistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in the cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317), and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Interestingly, the MCM3 levels did not affect the efficacy of growth inhibitory by CDK4/6 inhibitors. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic marker adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.

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.

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