The role of mitochondrial estrogen receptor β in relapse of breast cancer.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. e12540-e12540
Author(s):  
Tae Hyun Kim ◽  
In-Sung Song ◽  
Jin Han

e12540 Background: Breast cancer is the most common non-skin cancer in women. Breast cancers are heterogeneous, and treatment by subgroup based on hormone receptor and HER2 made a significant difference in clinical outcomes. Several studies have reported that estrogen receptor beta (ERβ) decreases during tumor development in the breast epithelium. However, the role of ERβ in relapse and metastasis of breast cancer is poorly understood. Methods: In this study, we retrospectively studied 30 case breast carcinomas divided luminal, HER2, and triple negative subtype. Among them, patients relapsed within 5 years are 6 cases. The expression of ERβ gene in breast cancer tissues (30 cases) was estimated using a quantitative PCR, and other marker (ERα, HER2, PR etc) was measured anonymously in formalin-fixed paraffin-embedded tumor sections, by using specific antibodies. Results: A low level of ERβ expression and mitochondrial translocation of ERβ was associated with relapse/metastasis of breast cancer. The ERβ depletion resulted in resistance in response to tamoxifen treatment of MCF-7 breast cancer cells. Conversely, the overexpression of mitochondrial ERβ enhanced the cell death by treatment of tamoxifen in MCF-7 cells. We found that ERβ localizes to the mitochondria via the interaction with Grp75 and improves mitochondrial oxygen consumption rate and ATP production in breast cancer cells. Finally, we showed that ERβ level was a low in the breast cancer stem cells (CD24-CD44+ cells) compared with breast non-cancer stem cells (CD24+CD44- cells), whereas ERα level was a high. The overexpression of mitochondrial ERβ contribute to a decrease of sphere formation showing a tumorigenic ability. Conclusions: The mitochondrial ERβ contribute to suppress survival and stemness of cancer stem cells for relapse/metastasis, promising to the development of novel strategies for the treatment of breast cancer patients.

2021 ◽  
Author(s):  
Ningwei Fu ◽  
Ning Fan ◽  
Wenchao Luo ◽  
Lijia Lv ◽  
Jing Li ◽  
...  

Abstract Purpose: TFEB is a key regulator of autophagy-lysosomal biogenesis pathways, while its dysregulation is highly prevalent in various human cancers, but the specific contribution to breast cancer remains poorly understood. The main purpose of this study is to explore the role of TFEB in breast cancer proliferation, metastasis and maintaining breast cancer stem cells (BCSCs) traits, thus uncovering its underlying mechanism.Methods: Bioinformatics, western blotting and immunohistochemical staining were applied to analyze the expression of TFEB in breast cancer. Stable down-regulation TFEB cells were established in MCF-7 and MDA-MB-231 breast cancer cell lines. MTT, clone formation, wound healing, transwell and 3D tumor invasion assays were used to evaluate the proliferation, migration and invasion ability of breast cancer cells. Mammosphere formation, immunocytochemical (ICC) staining were used to detect the effect of down-regulating TFEB on breast cancer stem cells. Results: we demonstrated that higher expression of TFEB was found in breast cancer. TFEB depletion had inhibitory effects on cellular proliferation, migration and invasion of breast cancer cells. Moreover, knockdown TFEB decreased mammosphere formation ability of BCSCs and expression of cancer stem cell markers. Autophagy-lysosomal related proteins were decreased by down regulation of TFEB. Conclusion: we uncovered a critical role of TFEB in breast cancer proliferation and metastasis, and BCSCs self-renewal and stemness. The underlying mechanisms involve in maintaining BCSCs traits, and dysregulating lysosome functions.


2010 ◽  
Vol 13 (2) ◽  
pp. 136 ◽  
Author(s):  
Jia Guo ◽  
Wan-Liang Lu

PURPOSE: The cancer stem cells play an important role in the invasion, metastasis and relapse of cancers as they are resistant to regular chemotherapy. In the present study, stealth liposomal daunorubicin plus tamoxifen was developed for eradicating breast cancer cells together with cancer stem cells. METHODS: Inhibitory effects were performed on the bulk human breast cancer cells (MCF-7), the sorted MCF-7 cancer stem-like cells (side population, SP), and the sorted MCF-7 cancer cells (NSP), respectively. Antitumor activity and TUNEL analysis were evaluated on the MCF-7 xenografts in nude mice. RESULTS: The encapsulation efficiencies of daunorubicin and tamoxifen were 95% and 90%, respectively. The mean particle size of the stealth liposomes was about 100 nm. Breast cancer stem cells were identified by the specific markers CD44+/CD24-, and isolated from bulk MCF-7 cells. When applying stealth liposomal daunorubicin plus tamoxifen, the inhibitory effects on both the breast cancer cells and the cancer stem cells were significantly increased in vitro, respectively. In the MCF-7 xenografts in mice, stealth liposomal daunorubicin plus tamoxifen showed the most favorable antitumor activity due to the passive targeting the tumor tissue and the synergistic effects in eliminating breast cancer cells and cancer stem cells. CONCLUSION: Stealth liposomal daunorubicin plus tamoxifen could have the potentials in eliminating both breast cancer cells and cancer stem cells.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Pramod Darvin ◽  
Varun Sasidharan Nair ◽  
Eyad Elkord

Tumor progression through immune evasion is a major challenge in cancer therapy. Recent studies revealed that enhanced PD-L1 expression in cancer stem cells is linked to immune evasion. Understanding the mechanisms behind this PD-L1 overexpression in cancer stem cells is critical for developing more effective strategies for preventing immune evasion and increasing the efficacy of anti-PD-1/PD-L1 therapy. Tumorsphere formation in breast cancer cells enhanced epithelial to mesenchymal transition (EMT), which is evident by increased expression of mesenchymal markers. In this study, we analyzed CpG methylation of PD-L1 promoter in MCF-7 and BT-549 breast cancer cells and tumorspheres derived from them. PD-L1 promoter was significantly hypomethylated in MCF-7 tumorspheres, but not from BT-549 tumorspheres, compared with their cell line counterparts. The active demethylation of PD-L1 promoter was confirmed by the increase in the distribution of 5hmC and decrease in 5mC levels and the upregulation of TET3 and downregulation of DNMTs enzymes in MCF-7 tumorspheres, compared with the cell line. Additionally, we checked the distribution of repressive histones H3K9me3, H3K27me3, and active histone H3K4me3 in the PD-L1 promoter. We found that distribution of repressive histones to the PD-L1 promoter was lower in tumorspheres, compared with cell lines. Moreover, an overexpression of histone acetylation enzymes was observed in tumorspheres suggesting the active involvement of histone modifications in EMT-induced PD-L1 expression. In summary, EMT-associated overexpression of PD-L1 was partially independent of promoter CpG methylation and more likely to be dependent on posttranslational histone modifications.


2019 ◽  
Vol 25 (2) ◽  
pp. 159-169
Author(s):  
Hee-Bin Park ◽  
Yun-Ji Kim ◽  
Seong-Min Lee ◽  
James S. Park ◽  
Keun-Sik Kim

Nutrients ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2839 ◽  
Author(s):  
Laetitia Delort ◽  
Lauriane Bougaret ◽  
Juliette Cholet ◽  
Marion Vermerie ◽  
Hermine Billard ◽  
...  

Obesity, a recognized risk factor for breast cancer in postmenopausal women, is associated with higher mortality rates regardless of menopausal status, which could in part be explained by therapeutic escape. Indeed, adipose microenvironment has been described to influence the efficiency of chemo- and hormonal therapies. Residual cancer stem cells could also have a key role in this process. To understand the mechanisms involved in the reduced efficacy of hormonal therapy on breast cancer cells in the presence of adipose secretome, human adipose stem cells (hMAD cell line) differentiated into mature adipocytes were co-cultured with mammary breast cancer cells and treated with hormonal therapies (tamoxifen, fulvestrant). Proliferation and apoptosis were measured (fluorescence test, impedancemetry, cytometry) and the gene expression profile was evaluated. Cancer stem cells were isolated from mammospheres made from MCF-7. The impact of chemo- and hormonal therapies and leptin was evaluated in this population. hMAD-differentiated mature adipocytes and their secretions were able to increase mammary cancer cell proliferation and to suppress the antiproliferative effect of tamoxifen, confirming previous data and validating our model. Apoptosis and cell cycle did not seem to be involved in this process. The evaluation of gene expression profiles suggested that STAT3 could be a possible target. On the contrary, leptin did not seem to be involved. The study of isolated cancer stem cells revealed that their proliferation was stimulated in the presence of anticancer therapies (tamoxifen, fulvestrant, doxorubicine) and leptin. Our study confirmed the role of adipocytes and their secretome, but above all, the role of communication between adipose and cancer cells in interfering with the efficiency of hormonal therapy. Among the pathophysiological mechanisms involved, leptin does not seem to interfere with the estrogenic pathway but seems to promote the proliferation of cancer stem cells.


2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
S. H. Shahruzaman ◽  
M. F. Mustafa ◽  
S. Ramli ◽  
S. Maniam ◽  
S. Fakurazi ◽  
...  

Breast cancer is the leading cause of cancer death in women in over 100 countries worldwide and accounts for almost 1 in 4 cancer cases among women. Baeckea frutescens of the family Myrtaceae has been used in traditional medicine and is known to possess antibacterial, antipyretic, and cytoprotective properties. In this study, we investigated the role of Baeckea frutescens branches extracts against human breast cancer cells. Baeckea frutescens branches extracts were prepared using Soxhlet apparatus with solvents of different polarity. The selective cytotoxic activity and the glucose consumption rate of Baeckea frutescens branches extracts of various concentrations (20 to 160 ug/ml) at 24-, 48-, and 72-hour time points were studied using MTT and glucose uptake assay. The IC50 values in human breast cancer (MCF-7 and MDA-MB-231) and mammary breast (MCF10A) cell lines were determined. Apoptotic study using AO/PI double staining was performed using fluorescent microscopy. The glucose uptake was measured using 2-NBDG, a fluorescent glucose analogue. The phytochemical screening of major secondary metabolites in plants was performed. This study reports that Baeckea frutescens branches extracts showed potent selective cytotoxic activity against MCF-7 cells compared to MDA-MB-231 cells after 72 hours of treatment. Evidence of early apoptosis which includes membrane blebbing and chromatin condensation was observed after 72 hours of treatment with Baeckea frutescens branches extracts. Interestingly, for the glucose uptake assay, the inhibition was observed as early as 24 hours upon treatment. All Baeckea frutescens extracts showed the presence of major secondary metabolites such as tannin, triterpenoid, flavonoid, and phenol. However, alkaloid level was unable to be determined. The identification of Baeckea frutescens and its possible role in selectively inhibiting glucose consumption in breast cancer cells defines a new role of natural product that can be utilised as an effective agent that regulates metabolic reprogramming in breast cancer.


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