scholarly journals A DOCK1 Gene-Derived Circular RNA Is Highly Expressed in Luminal Mammary Tumours and Is Involved in the Epithelial Differentiation, Growth, and Motility of Breast Cancer Cells

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5325
Author(s):  
Mami Kurosaki ◽  
Mineko Terao ◽  
Dawei Liu ◽  
Adriana Zanetti ◽  
Luca Guarrera ◽  
...  

Circular RNAs are regulatory molecules involved in numerous cellular processes and may be involved in tumour growth and diffusion. Here, we define the expression of 15 selected circular RNAs, which may control the process of epithelial-to-mesenchymal transition, using a panel of 18 breast cancer cell lines recapitulating the heterogeneity of these tumours and consisting of three groups according to the mesenchymal/epithelial phenotype. A circular RNA from the DOCK1 gene (hsa_circ_0020397) shows low/undetectable levels in triple-negative mesenchymal cell lines, while its content is high in epithelial cell lines, independent of estrogen receptor or HER2 positivity. RNA-sequencing experiments performed on the triple-negative/mesenchymal MDA-MB-231 and MDA-MB-157 cell lines engineered to overexpress hsa_circ_0020397 demonstrate that the circRNA influences the expression of 110 common genes. Pathway analysis of these genes indicates that overexpression of the circular RNA differentiates the two mesenchymal cell lines along the epithelial pathway and increases cell-to-cell adhesion. This is accompanied by growth inhibition and a reduction in the random/directional motility of the cell lines. The upregulated AGR2, ENPP1, and PPP1R9A genes as well as the downregulated APOE, AQP3, CD99L2, and IGFBP4 genes show an opposite regulation by hsa_circ_0020397 silencing in luminal CAMA1 cells. The results provide novel insights into the role played by specific circular RNAs in the generation/progression of breast cancer.

2021 ◽  
Author(s):  
Ozge ALVUR ◽  
Hakan KUCUKSAYAN ◽  
Yasemin BAYGU ◽  
Nilgun KABAY ◽  
Yasar GOK ◽  
...  

Abstract Breast cancer is a heterogeneous disease which has distinct subtypes and therefore development of novel targeting treatments to fight aganist breast cancer is needed. Although autophagy and apoptosis considered as the major programmed cell death mechanisms are among the current target mechanisms, there are some difficulties in clinical treatment such as the development of drug resistance and cancer recurrence. Therefore it is important that illumination of distinctive mechanisms between cancer types for development novel treatment strategies. In this study, we examined the anti-proliferative effects of the triazole linked galactose substituted dicyano compound (hereafter referred to as the dicyano compound (the DC)) on two different breast cancer cell lines, MDA-MB-231 and MCF-7. We determined that response of each cell lines to the DC was different, since autophagy was induced in MDA-MB-231 and apoptosis was induced in MCF-7. For this reason, we hypothesized that these different responses may be due to the different characteristics of the cells and evaluated effects of aggresiveness degrees of both cell lines on response to the DC. As a result of our analysis, we determined that c-Myc regulation in both cell lines was different upon the DC treatment depending on expression of Twist, an epithelial-to-mesenchymal transition (EMT) mediator. Therefore, we suggest that Twist/c-Myc axis may have a role in different response to the DC-induced cell death pathways in breast cancer subtypes.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Xinyu Deng ◽  
Morris Kohanfars ◽  
Huan Ming Hsu ◽  
Puneet Souda ◽  
Joe Capri ◽  
...  

Because of the absence of a clear therapeutic target for triple negative breast cancer (TNBC), conventional chemotherapy is the only available systemic treatment option for these patients. Despite chemotherapy treatment, TNBC patients still have worse prognosis when compared with other breast cancer patients. The study is to investigate unique phosphorylated proteins expressed in chemoresistant TNBC cell lines. In the current study, twelve TNBC cell lines were subjected to drug sensitivity assays against chemotherapy drugs docetaxel, doxorubicin, gemcitabine, and cisplatin. Based on their half maximal inhibitory concentrations, four resistant and two sensitive cell lines were selected for further analysis. The phosphopeptides from these cells were enriched with TiO2 beads and fractionated using strong cation exchange. 1,645 phosphoprotein groups and 9,585 unique phosphopeptides were identified by a high throughput LC-MS/MS system LTQ-Orbitrap. The phosphopeptides were further filtered with Ascore system and 1,340 phosphoprotein groups, 2,760 unique phosphopeptides, and 4,549 unique phosphosites were identified. Our study suggested that differentially phosphorylated Cdk5, PML, AP-1, and HSF-1 might work together to promote vimentin induced epithelial to mesenchymal transition (EMT) in the drug resistant cells. EGFR and HGF were also shown to be involved in this process.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Farzaneh Darbeheshti ◽  
Elham Zokaei ◽  
Yaser Mansoori ◽  
Sima Emadi Allahyari ◽  
Zeeba Kamaliyan ◽  
...  

Abstract Background Circular RNAs (circRNAs) have been implicated in the initiation and development of breast cancer as functional non-coding RNAs (ncRNA). The roles of circRNAs as the competing endogenous RNAs (ceRNAs) to sponge microRNAs (miRNAs) have also been indicated. However, the functions of circRNAs in breast cancer have not been totally elucidated. This study aimed to explore the clinical implications and possible roles of circ_0044234 in carcinogenesis of the most problematic BC subtype, triple negative breast cancer (TNBC), which are in desperate need of biomarkers and targeted therapies. Methods The importance of circ_0044234 as one of the most dysregulated circRNAs in TNBC was discovered through microarray expression profile analysis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to confirm the downregulation of circ_0044234 in triple negative tumors and cell lines versus non-triple negative ones. The bioinformatics prediction revealed that circ_0044234 could act as an upstream sponge in the miR-135b/GATA3 axis, two of the most dysregulated transcripts in TNBC. Results Our experimental investigation of circ_0044234 expressions in various BC subtypes as well as cell lines reveals that TNBC expresses circ_0044234 at a substantially lower level than non-TNBC. The ROC curve analysis indicates that it could be applied as a discriminative biomarker to identify TNBC from other BC subtypes. Moreover, circ_0044234 expression could be an independent prognostic biomarker in BC. Interestingly, a substantial inverse expression correlation was detected between circ_0044234 and miR-135b-5p as well as between miR-135b-5p and GATA3 in breast tumors. Conclusions The possible clinical usefulness of circ_0044234 as a promising distinct biomarker and upcoming therapeutic target for TNBC have been indicated in this research. Our comprehensive approach revealed the potential circ_0044234/miR135b-5p/GATA3 ceRNA axis in TNBC.


2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Xinxing Wang ◽  
Bingjian Xue ◽  
Yujie Zhang ◽  
Guangcheng Guo ◽  
Xin Duan ◽  
...  

AbstractAn increasing amount of evidence has proven the vital role of circular RNAs (circRNAs) in cancer progression. However, there remains a dearth of knowledge on the function of circRNAs in triple-negative breast cancer (TNBC). Utilizing a circRNA microarray dataset, four circRNAs were identified to be abnormally expressed in TNBC. Among them, circBACH2 was most significantly elevated in TNBC cancerous tissues and its high expression was positively correlated to the malignant progression of TNBC patients. In normal human mammary gland cell line, the overexpression of circBACH2 facilitated epithelial to mesenchymal transition and cell proliferation. In TNBC cell lines, circBACH2 knockdown suppressed the malignant progression of TNBC cells. Mechanistically, circBACH2 sponged miR-186-5p and miR-548c-3p, thus releasing the C-X-C chemokine receptor type 4 (CXCR4) expression. The interference of miR-186-5p/miR-548c-3p efficiently promoted the cell proliferation, migration, and invasion suppressed by circBACH2 knockdown in the TNBC cell lines. Finally, circBACH2 knockdown repressed the growth and lung metastasis of TNBC xenografts in nude mice. In summary, circBACH2 functions as an oncogenic circRNA in TNBC through a novel miR-186-5p/miR-548c-3p/CXCR4 axis.


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