Down-regulation of lncRNA-ATB inhibits epithelial–mesenchymal transition of breast cancer cells by increasing miR-141-3p expression

2019 ◽  
Vol 97 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Yang Zhang ◽  
Jianyi Li ◽  
Shi Jia ◽  
Yitong Wang ◽  
Ye Kang ◽  
...  

Long noncoding RNA activated by transforming growth factor-beta (lnc-ATB) is abnormally expressed in a number of tumor types. The aim of this study was to investigate the expression of lnc-ATB and miR-141-3p, and to determine whether lnc-ATB can regulate epithelial–mesenchymal transition (EMT) by miR-141-3p in breast cancer. Here, we found that lnc-ATB was highly expressed, whereas there was low expression of miR-141-3p in breast cancer tissues and cells. Knockdown of lnc-ATB in two breast cancer cell lines (MDA-MB-231 and BT549) significantly increased miR-141-3p expression. Down-regulation of lnc-ATB resulted in a morphological change of breast cancer cells from spindle-like to a round shape, and in a remarkable inhibition of cell migration and invasion, which were reversed by miR-141-3p inhibitor. Furthermore, we demonstrated that lnc-ATB knockdown decreased ZEB1, ZEB2, N-cadherin, and vimentin expression, and promoted E-cadherin expression, while miR-141-3p inhibitor could reverse those effects. Moreover, we proved that miR-141-3p directly bound to the 3′ untranslated region (UTR) of ZEB1 and ZEB2 and negatively regulated ZEB1 and ZEB2 expression. Taken together, our results show that knockdown of lnc-ATB significantly inhibits the EMT process of breast cancer cells by increasing the expression of miR-141-3p, indicating that lnc-ATB might serve as a novel therapeutic target for breast cancer.

2020 ◽  
pp. jbc.RA120.016345
Author(s):  
Qiong Wu ◽  
Cheng Zhang ◽  
Keren Zhang ◽  
Qiushi Chen ◽  
Sijin Wu ◽  
...  

GalNAc-type O-glycosylation, initially catalyzed by polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts), is one of the most abundant and complex post-translational modifications of proteins. Emerging evidence has proven that aberrant ppGalNAc-Ts are involved in malignant tumor transformation. However, the exact molecular functions of ppGalNAc-Ts are still unclear. Here, the role of one isoform, ppGalNAc-T4, in breast cancer cell lines was investigated. The expression of ppGalNAc-T4 was found to be negatively associated with migration of breast cancer cells. Loss-of function studies revealed that ppGalNAc-T4 attenuated the migration and invasion of breast cancer cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Correspondingly, transforming growth factor beta (TGF-β) signaling, which is the upstream pathway of EMT, was impaired by ppGalNAc-T4 expression. ppGalNAc-T4 knock-out decreased O-GalNAc modification of TGF-β type Ⅰ and Ⅱ receptor (TβR Ⅰ and Ⅱ) and led to the elevation of TGF-β receptor dimerization and activity. Importantly, a peptide from TβR Ⅱ was first identified as the naked peptide substrate of ppGalNAc-T4 with a higher affinity than ppGalNAc-T2. Further, Ser31, corresponding to the extracellular domain of TβR Ⅱ, was identified as the O-GalNAcylation site upon in vitro glycosylation by ppGalNAc-T4. The O-GalNAc-deficient S31A mutation enhanced TGF-β signaling activity and EMT in breast cancer cells. Together, these results identified a novel mechanism of ppGalNAc-T4-catalyzed TGF-β receptors O-GalNAcylation that suppresses breast cancer cell migration and invasion via the EMT process. Targeting ppGalNAc-T4 may be a potential therapeutic strategy for breast cancer treatment.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jiraporn Kantapan ◽  
Siwaphon Paksee ◽  
Aphidet Duangya ◽  
Padchanee Sangthong ◽  
Sittiruk Roytrakul ◽  
...  

Abstract Background Radioresistance can pose a significant obstacle to the effective treatment of breast cancers. Epithelial–mesenchymal transition (EMT) is a critical step in the acquisition of stem cell traits and radioresistance. Here, we investigated whether Maprang seed extract (MPSE), a gallotannin-rich extract of seed from Bouea macrophylla Griffith, could inhibit the radiation-induced EMT process and enhance the radiosensitivity of breast cancer cells. Methods Breast cancer cells were pre-treated with MPSE before irradiation (IR), the radiosensitizing activity of MPSE was assessed using the colony formation assay. Radiation-induced EMT and stemness phenotype were identified using breast cancer stem cells (CSCs) marker (CD24−/low/CD44+) and mammosphere formation assay. Cell motility was determined via the wound healing assay and transwell migration. Radiation-induced cell death was assessed via the apoptosis assay and SA-β-galactosidase staining for cellular senescence. CSCs- and EMT-related genes were confirmed by real-time PCR (qPCR) and Western blotting. Results Pre-treated with MPSE before irradiation could reduce the clonogenic activity and enhance radiosensitivity of breast cancer cell lines with sensitization enhancement ratios (SERs) of 2.33 and 1.35 for MCF7 and MDA-MB231cells, respectively. Pretreatment of breast cancer cells followed by IR resulted in an increased level of DNA damage maker (γ-H2A histone family member) and enhanced radiation-induced cell death. Irradiation induced EMT process, which displayed a significant EMT phenotype with a down-regulated epithelial marker E-cadherin and up-regulated mesenchymal marker vimentin in comparison with untreated breast cancer cells. Notably, we observed that pretreatment with MPSE attenuated the radiation-induced EMT process and decrease some stemness-like properties characterized by mammosphere formation and the CSC marker. Furthermore, pretreatment with MPSE attenuated the radiation-induced activation of the pro-survival pathway by decrease the expression of phosphorylation of ERK and AKT and sensitized breast cancer cells to radiation. Conclusion MPSE enhanced the radiosensitivity of breast cancer cells by enhancing IR-induced DNA damage and cell death, and attenuating the IR-induced EMT process and stemness phenotype via targeting survival pathways PI3K/AKT and MAPK in irradiated breast cancer cells. Our findings describe a novel strategy for increasing the efficacy of radiotherapy for breast cancer patients using a safer and low-cost natural product, MPSE.


2014 ◽  
Vol 60 (3) ◽  
pp. 322-331 ◽  
Author(s):  
E.A. Avilova ◽  
O.E. Andreeva ◽  
V.A. Shatskaya ◽  
M.A. Krasilnikov

The main goal of this work was to study the intracellular signaling pathways responsible for the development of hormone resistance and maintaining the autonomous growth of breast cancer cells. In particular, the role of PAK1 (p21-activated kinase 1), the key mitogenic signaling protein, in the development of cell resistance to estrogens was analyzed. In vitro studies were performed on cultured breast cancer cell lines: estrogen-dependent estrogen receptor (ER)-positive MCF-7 cells and estrogen-resistant ER-negative HBL-100 cells. We found that the resistant HBL-100 cells were characterized by a higher level of PAK1 and demonstrated PAK1 involvement in the maintaining of estrogen-independent cell growth. We have also shown PAK1 ability to up-regulate Snail1, one of the epithelial-mesenchymal transition proteins, and obtained experimental evidence for Snail1 importance in the regulation of cell proliferation. In general, the results obtained in this study demonstrate involvement of PAK1 and Snail1 in the formation of estrogen-independent phenotype of breast cancer cells showing the potential role of both proteins as markers of hormone resistance of breast tumors.


2021 ◽  
Author(s):  
zhuo Chen ◽  
jing Wu ◽  
liang Wang ◽  
hua Zhao ◽  
jie He

Abstract Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. More and more studies have shown that the tumor immune microenvironment (TME) of TNBC is closely related to its poor prognosis and early metastasis. We try to explain how tumor-associate macrophages (TAMs), an important component of the TME, function in the matrix of TNBC. Therefore, we induced THP-1 cells to become M1-TAMs and M2-TAMs, investigated their influence on breast cancer cells. 82 TNBC paraffin samples were made into tissue microarrays. The expression of macrophages makers were measured by immunohistochemistry. Scratch assay, Transwell assay, CCK-8 cell proliferation assay were performed in the co-culture system of breast cancer cells lines and macrophages to observe the invasion and proliferation ability of breast cancer cell lines. Western Blot (WB) was performed to detect the expression of E-cadherin (CDH1) and N-cadherin (CDH2). M2-TAMs were more numerous than M1-TAMs in the matrix of TNBC cancer nests and associated with poor prognosis. M2-TAMs promoted the invasion, migration and proliferation of TNBC cells. M1-TAMs had inhibitory effects. In MCF-7 cells, WB showed a decrease in CDH1 and an increase in CDH2. In MDA-MB-231 cells and BT549 cells, CDH2 expression was reduced and CDH1 expression was increased. All of the above results were statistically significant, p < 0.001. M2-TAMs were more numerous in TNBC and associated with poor prognosis. M2-TAMs promoted the invasion, migration and proliferation of breast cancer cells. The mechanism may be related to the epithelial-mesenchymal transition (EMT).


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