scholarly journals Cyclin D1 triggers autonomous growth of breast cancer cells by governing cell cycle exit.

1996 ◽  
Vol 16 (6) ◽  
pp. 2554-2560 ◽  
Author(s):  
R M Zwijsen ◽  
R Klompmaker ◽  
E B Wientjens ◽  
P M Kristel ◽  
B van der Burg ◽  
...  

Cyclin D1 controls G1-associated processes, including G0-to-G1 and G1-to-S transitions. This study demonstrates a novel aspect of cyclin D1 as a regulator of the transition between G1 and G0. Overexpression of cyclin D1 in MCF7 breast tumor cells resulted in a continued proliferation under low-serum conditions, whereas nonoverexpressing cells ceased to grow. This difference in growth was due to a reduced exit from G1 to G0 in cyclin D1-overexpressing cells. Our data therefore suggest a model in which cyclin D1 overexpression in tumor cells is responsible for hyperproliferation under growth factor-deprived conditions.

Author(s):  
Tatiane Renata Fagundes ◽  
Bruna Bortoleti ◽  
Priscila Camargo ◽  
Vírgínia Concato ◽  
Fernanda Tomiotto-Pellissier ◽  
...  

Background: Conventional therapies for breast cancer is still a challenge due to use of cytotoxic drugs not highly effective with major adverse effects. Thiohydantoins, are biologically active heterocyclic compounds reported by several biological activities, including anticarcinogenic properties, i.e., this work aimed to assess the use of thiohydantoin as a potential antitumor agent against MCF-7 breast cancer cells. Methods: MTT and neutral red assays were used to assess the possible cytotoxic activity of compounds against MCF-7 cells. Cell volume measurement and analysis were performed by flow cytometry, fluorescence analysis was carried out to determine patterns of cell death induced by thiohydantoins. Results: The treatment with micromolar doses of thiohydantoins promoted a decrease in the viability of MCF-7 breast tumor cells. Also were observed the increase in ROS and NO production, reduction in cell volume, loss of membrane integrity, mitochondrial depolarization, and increased fluorescence for annexin V and caspase-3. These findings indicate cell death by apoptosis and increased formation of autophagic vacuoles and stopping the cell cycle in the G1/ G0 phase. Conclusions: Our results indicate that thiohydantoins are cytotoxic to breast tumor cells, and this effect is linked to the increase in ROS production. This phenomenon changes tumorigenic pathways, that lead to a halt of the cell cycle in G1/G0, an important checkpoint for DNA errors, which may have altered the process by which cells produce energy, causing a decrease in mitochondrial viability and thus leading to the apoptotic process. Furthermore, the results indicate increased autophagy, a vital process linked to a decrease in lysosomal viability and considered as a cell death and tumor suppression mechanism.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Qing Ma ◽  
Yang Gao ◽  
Pei Xu ◽  
Kai Li ◽  
Xiaolong Xu ◽  
...  

Background. Breast cancer (BC) is one of the most common malignant tumors in women around the world. Atorvastatin (ATO) was found to be associated with a decreased risk of recurrence and mortality in cancer. But the exact mechanism of its carcinostatic effects is unclear. The expression level of Ras homolog family member B (RhoB) in breast cancer cells was found to be upregulated after being treated with ATO. Thus, we conjecture that altered expression of RhoB induced by ATO may be decisive for the migration and progression of breast cancer. Methods. The effects of ATO on breast tumor cells in vivo and in vitro were detected by clone formation assay, CCK-8 assay, flow cytometry, wound healing, transwell assays, tumor xenograft model, and immunohistochemistry. Distribution of RhoB in different breast cancer tissues and its influence on prognosis were analyzed using the data from TCGA or GEO databases. The relationship between RhoB and PTEN/AKT pathway was detected by Western blotting and RT-qPCR. Results. ATO inhibits proliferation, invasion, EMT, and PTEN/AKT pathway and promotes apoptosis in breast tumor cells. In addition, ATO inhibits the volume and weight of breast tumor in tumor-bearing mice and upregulated RhoB in tumor tissues. The expression of RhoB in mRNA and protein level was upregulated in statin-treated breast cancer cells and downregulated in cancer tissues. Low expression of RhoB links with poor prognosis in patients with breast cancer (HR = 0.74[0.66–0.83], p =7e−8, log-rank test). Further research found that RhoB inhibits the proliferation, invasion, EMT, and PTEN/AKT signal pathway in breast tumor cells. Conclusions. The exact mechanism of ATO’s carcinostatic effects in breast cancer is related to downregulating PTEN/AKT pathway via promoting RhoB. Our study also demonstrates the potential applicability of RhoB as a therapeutic target for breast cancer.


Endocrinology ◽  
2008 ◽  
Vol 149 (8) ◽  
pp. 3799-3808 ◽  
Author(s):  
Lidia Albanito ◽  
Diego Sisci ◽  
Saveria Aquila ◽  
Elvira Brunelli ◽  
Adele Vivacqua ◽  
...  

Different cellular receptors mediate the biological effects induced by estrogens. In addition to the classical nuclear estrogen receptors (ERs)-α and -β, estrogen also signals through the seven-transmembrane G-protein-coupled receptor (GPR)-30. Using as a model system SkBr3 and BT20 breast cancer cells lacking the classical ER, the regulation of GPR30 expression by 17β-estradiol, the selective GPR30 ligand G-1, IGF-I, and epidermal growth factor (EGF) was evaluated. Transient transfections with an expression plasmid encoding a short 5′-flanking sequence of the GPR30 gene revealed that an activator protein-1 site located within this region is required for the activating potential exhibited only by EGF. Accordingly, EGF up-regulated GPR30 protein levels, which accumulated predominantly in the intracellular compartment. The stimulatory role elicited by EGF on GPR30 expression was triggered through rapid ERK phosphorylation and c-fos induction, which was strongly recruited to the activator protein-1 site found in the short 5′-flanking sequence of the GPR30 gene. Of note, EGF activating the EGF receptor-MAPK transduction pathway stimulated a regulatory loop that subsequently engaged estrogen through GPR30 to boost the proliferation of SkBr3 and BT20 breast tumor cells. The up-regulation of GPR30 by ligand-activated EGF receptor-MAPK signaling provides new insight into the well-known estrogen and EGF cross talk, which, as largely reported, contributes to breast cancer progression. On the basis of our results, the action of EGF may include the up-regulation of GPR30 in facilitating a stimulatory role of estrogen, even in ER-negative breast tumor cells.


Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1285 ◽  
Author(s):  
Mohr ◽  
Gross ◽  
Sezgin ◽  
Steudel ◽  
Ruth ◽  
...  

KCa3.1 K+ channels reportedly contribute to the proliferation of breast tumor cells and may serve pro-tumor functions in the microenvironment. The putative interaction of KCa3.1 with major anti-cancer treatment strategies, which are based on cytotoxic drugs or radiotherapy, remains largely unexplored. We employed KCa3.1-proficient and -deficient breast cancer cells derived from breast cancer-prone MMTV-PyMT mice, pharmacological KCa3.1 inhibition, and a syngeneic orthotopic mouse model to study the relevance of functional KCa3.1 for therapy response. The KCa3.1 status of MMTV-PyMT cells did not determine tumor cell proliferation after treatment with different concentrations of docetaxel, doxorubicin, 5-fluorouracil, or cyclophosphamide. KCa3.1 activation by ionizing radiation (IR) in breast tumor cells in vitro, however, enhanced radioresistance, probably via an involvement of the channel in IR-stimulated Ca2+ signals and DNA repair pathways. Consistently, KCa3.1 knockout increased survival time of wildtype mice upon syngeneic orthotopic transplantation of MMTV-PyMT tumors followed by fractionated radiotherapy. Combined, our results imply that KCa3.1 confers resistance to radio- but not to chemotherapy in the MMTV-PyMT breast cancer model. Since KCa3.1 is druggable, KCa3.1 targeting concomitant to radiotherapy seems to be a promising strategy to radiosensitize breast tumors.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 641
Author(s):  
Kaitlin M. Branch ◽  
Erica C. Garcia ◽  
Yin Maggie Chen ◽  
Matthew McGregor ◽  
Mikayla Min ◽  
...  

Breast cancer is the leading cause of cancer deaths among women worldwide. There are many known risk factors for breast cancer, but the role of infectious disease remains unclear. Human cytomegalovirus (HCMV) is a widespread herpesvirus that usually causes little disease. Because HCMV has been detected in breast tumor biopsy samples and is frequently transmitted via human breast milk, we investigated HCMV replication in breast tumor cells. Four human breast cancer cell lines with different expression profiles for the key diagnostic markers of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), were infected with a bacterial artificial chromosome-derived HCMV clinical strain TB40/E tagged with green fluorescent protein (GFP). Fluorescence microscopy confirmed that all four breast cancer cell lines supported virus entry. RNA was isolated from infected cells and the expression of immediate early (UL123), early (UL54), and late (UL111A) genes was confirmed using PCR. Viral proteins were detected by immunoblotting, and viral progeny were produced during the infection of breast tumor cells, as evidenced by subsequent infection of fibroblasts with culture supernatants. These results demonstrate that breast tumor cells support productive HCMV infection and could indicate that HCMV replication may play a role in breast cancer progression.


Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 442 ◽  
Author(s):  
Yu-Dong Zhou ◽  
Jun Li ◽  
Lin Du ◽  
Fakhri Mahdi ◽  
Thuy Le ◽  
...  

Breast tumors reprogram their cellular metabolism, nutrient uptake, and utilization-associated biochemical processes. These processes become further transformed as genetically predisposed metastatic breast tumor cells colonize specific organs. Breast tumor cells often metastasize to the brain, bone, lung and liver. Massagué and colleagues isolated organotropic subclones and established organ-specific gene signatures associated with lung-, bone-, and brain-specific metastatic triple-negative breast cancer (TNBC) MDA-MB-231 cells. Using these genetically characterized metastatic subclones specific to lung (LM4175), bone (BoM1833), and brain (BrM-2a), we evaluated marine natural products for the ability to differentially suppress metastatic breast cancer cells in a target organ-dependent manner. Psammaplin-based histone deacetylase (HDAC) inhibitors were found to differentially inhibit HDAC activity, induce activation of hypoxia-inducible factor-1 (HIF-1), and disrupt organotropic metastatic TNBC subclone growth. Further, psammaplins distinctly suppressed the outgrowth of BoM1833 tumor spheroids in 3D-culture systems. Similar results were observed with the prototypical HDAC inhibitor trichostatin A (TSA). These organotropic tumor cell-based studies suggest the potential application of HDAC inhibitors that may yield new directions for anti-metastatic breast tumor research and drug discovery.


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