scholarly journals Adipocytes Under Obese-Like Conditions Change Cell Cycle Distribution and Phosphorylation Profiles of Breast Cancer Cells: The Adipokine Receptor CAP1 Matters

2021 ◽  
Vol 11 ◽  
Author(s):  
Malin Bergqvist ◽  
Karin Elebro ◽  
Signe Borgquist ◽  
Ann H. Rosendahl

BackgroundObesity and associated metabolic conditions impact adipocyte functionality with potential consequences for breast cancer risk and prognosis, but contributing mechanisms remain to be understood. The adipokine receptor adenylyl cyclase-associated protein-1 (CAP1) has been implicated in the progression of breast cancer, but results are conflicting and the underlying molecular mechanisms are still unknown. In this study, molecular and cellular effects in breast cancer cells by stimulation of adipocytes under normal or obese-like conditions, and potential involvement of CAP1, were assessed.Material and MethodsEstrogen receptor (ER)-positive T47D and ER-negative MDA-MB-231 breast cancer cells were exposed to adipocyte-secretome from adipocytes placed under pressures mimicking normal and obese-like metabolic conditions. Changes in phosphorylated kinase proteins and related biological pathways were assessed by phospho-antibody array and PANTHER analysis, cell proliferation were investigated through sulforhodamine B, cell cycle distribution by flow cytometry. Functional effects of CAP1 were subsequently examined following small interfering (si)RNA-mediated knockdown.ResultsProtein phosphorylations involved in important biological processes were enriched in T47D breast cancer cells in response to adipocyte secretome from obese-like compared with normal conditions. The obesity-associated adipocyte secretome further stimulated cell proliferation and a shift from cell cycle G1-phase to S- and G2/M-phase was observed. Silencing of CAP1 decreased cell proliferation in both T47D and MDA-MB-231 cells, and reduced the obesity-associated secretome-induction of phosphoproteins involved in cell proliferation pathways.ConclusionsThese results indicate that the adipocyte secretome and CAP1 are mechanistically important for the proliferation of both ER-positive and ER-negative breast cancer cells, and potential signaling mediators were identified. These studies provide biological insight into how obesity-associated factors could affect breast cancer.

2021 ◽  
Vol 13 (1) ◽  
pp. 17-29
Author(s):  
Emann M Rabie ◽  
Sherry X Zhang ◽  
Andreas P Kourouklis ◽  
A Nihan Kilinc ◽  
Allison K Simi ◽  
...  

Abstract Metastasis, the leading cause of mortality in cancer patients, depends upon the ability of cancer cells to invade into the extracellular matrix that surrounds the primary tumor and to escape into the vasculature. To investigate the features of the microenvironment that regulate invasion and escape, we generated solid microtumors of MDA-MB-231 human breast carcinoma cells within gels of type I collagen. The microtumors were formed at defined distances adjacent to an empty cavity, which served as an artificial vessel into which the constituent tumor cells could escape. To define the relative contributions of matrix degradation and cell proliferation on invasion and escape, we used pharmacological approaches to block the activity of matrix metalloproteinases (MMPs) or to arrest the cell cycle. We found that blocking MMP activity prevents both invasion and escape of the breast cancer cells. Surprisingly, blocking proliferation increases the rate of invasion but has no effect on that of escape. We found that arresting the cell cycle increases the expression of MMPs, consistent with the increased rate of invasion. To gain additional insight into the role of cell proliferation in the invasion process, we generated microtumors from cells that express the fluorescent ubiquitination-based cell cycle indicator. We found that the cells that initiate invasions are preferentially quiescent, whereas cell proliferation is associated with the extension of invasions. These data suggest that matrix degradation and cell proliferation are coupled during the invasion and escape of human breast cancer cells and highlight the critical role of matrix proteolysis in governing tumor phenotype.


2005 ◽  
Vol 34 (2) ◽  
pp. 535-551 ◽  
Author(s):  
J G Moggs ◽  
T C Murphy ◽  
F L Lim ◽  
D J Moore ◽  
R Stuckey ◽  
...  

Estrogen receptor (ER)-negative breast carcinomas do not respond to hormone therapy, making their effective treatment very difficult. The re-expression of ERα in ER-negative MDA-MB-231 breast cancer cells has been used as a model system, in which hormone-dependent responses can be restored. Paradoxically, in contrast to the mitogenic activity of 17β-estradiol (E2) in ER-positive breast cancer cells, E2 suppresses proliferation in ER-negative breast cancer cells in which ERα has been re-expressed. We have used global gene expression profiling to investigate the mechanism by which E2 suppresses proliferation in MDA-MB-231 cells that express ERα through adenoviral infection. We show that a number of genes known to promote cell proliferation and survival are repressed by E2 in these cells. These include genes encoding the anti-apoptosis factor SURVIVIN, positive cell cycle regulators (CDC2, CYCLIN B1, CYCLIN B2, CYCLIN G1, CHK1, BUB3, STK6, SKB1, CSE1 L) and chromosome replication proteins (MCM2, MCM3, FEN1, RRM2, TOP2A, RFC1). In parallel, E2-induced the expression of the negative cell cycle regulators KIP2 and QUIESCIN Q6, and the tumour-suppressor genes E-CADHERIN and NBL1. Strikingly, the expression of several of these genes is regulated in the opposite direction by E2 compared with their regulation in ER-positive MCF-7 cells. Together, these data suggest a mechanism for the E2-dependent suppression of proliferation in ER-negative breast cancer cells into which ERα has been reintroduced.


Oncogene ◽  
2009 ◽  
Vol 29 (2) ◽  
pp. 285-296 ◽  
Author(s):  
N H Thoennissen ◽  
J O'Kelly ◽  
D Lu ◽  
G B Iwanski ◽  
D T La ◽  
...  

Author(s):  
Mayu Ono ◽  
Takaaki Oba ◽  
Tomohiro Shibata ◽  
Ken-ichi Ito

Abstract Purpose Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are widely used for the treatment of advanced estrogen receptor (ER)-positive breast cancer. To develop a treatment strategy for cancers resistant to CDK4/6 inhibitors, here, we established palbociclib-resistant sublines and analyzed their resistance mechanisms. Methods Palbociclib-resistant sublines were established from T47D and MCF7 cells. Sensitivity to other drugs was assessed via the WST assay. Altered expression/phosphorylation of proteins related to signal transduction and cell cycle regulation was examined using western blotting. Copy number alterations and mutations in the retinoblastoma (RB1) gene were also analyzed. Results Although an increase in CDK6 and decrease in retinoblastoma protein (Rb) expression/phosphorylation were commonly observed in the resistant sublines, changes in other cell cycle-related proteins were heterogeneous. Upon extended exposure to palbociclib, the expression/phosphorylation of these proteins became altered, and the long-term removal of palbociclib did not restore the Rb expression/phosphorylation patterns. Consistently a copy number decrease, as well as RB1 mutations were detected. Moreover, although the resistant sublines exhibited cross-resistance to abemaciclib, their response to dinaciclib was the same as that of wild-type cells. Of note, the cell line exhibiting increased mTOR phosphorylation also showed a higher sensitivity to everolimus. However, the sensitivity to chemotherapeutic agents was unchanged in palbociclib-resistant sublines. Conclusion ER-positive breast cancer cells use multiple molecular mechanisms to survive in the presence of palbociclib, suggesting that targeting activated proteins may be an effective strategy to overcome resistance. Additionally, palbociclib monotherapy induces mutations and copy number alterations in the RB1 gene.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Stéphane Zingue ◽  
Abel Joël Gbaweng Yaya ◽  
Julia Cisilotto ◽  
Larissa Vanelle Kenmogne ◽  
Emmanuel Talla ◽  
...  

Abyssinone V-4′ methyl ether (AVME) isolated from Erythrina droogmansiana was recently reported to exhibit anti-mammary tumor effect in mice. The present work was therefore aimed at elucidating its cellular and molecular mechanisms. To achieve our goal, the cytotoxicity of AVME against tumoral and non-tumoral cell lines was evaluated by resazurin reduction test; flow cytometry allowed us to evaluate the cell cycle and mechanisms of cell death; the mitochondrial transmembrane potential, reactive oxygen species (ROS) levels, and caspase activities as well as apoptosis-regulatory proteins (Bcl-2 and Bcl-XL) were measured in MDA-MB-231 cells. Further, the antimetastatic potential of AVME was evaluated by invasion assay. AVME exhibited cytotoxic effects in all tested tumor cell lines and induced a significant increase in the percentage of MDA-MB-231 cells at G2/M and S phases of the cell cycle in a concentration-dependent manner. AVME also induced apoptosis in MDA-MB-231 cells, which was accompanied by the activation of caspase-3 and caspase-9 and downregulation of Bcl-2 and Bcl-XL proteins. Moreover, AVME suppressed cancer cell invasion by the inhibition of the metalloproteinase-9 activity. Findings from this study suggest that AVME has anti-breast cancer activities expressed through mitochondrial proapoptotic pathway including impairment of aggressive behaviors of breast cancer cells.


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