scholarly journals Splicing factors control triple-negative breast cancer cell mitosis through SUN2 interaction and sororin intron retention

Author(s):  
Esmee Koedoot ◽  
Eline van Steijn ◽  
Marjolein Vermeer ◽  
Román González-Prieto ◽  
Alfred C. O. Vertegaal ◽  
...  

Abstract Background Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited therapeutic opportunities. Recently, splicing factors have gained attention as potential targets for cancer treatment. Here we systematically evaluated the role of RNA splicing factors in TNBC cell proliferation. Methods In this study, we performed an RNAi screen targeting 244 individual splicing factors to systematically evaluate their role in TNBC cell proliferation. For top candidates, mechanistic insight was gained using amongst others western blot, PCR, FACS, molecular imaging and cloning. Pulldown followed by mass spectrometry were used to determine protein-protein interactions and patient-derived RNA sequencing data was used relate splicing factor expression levels to proliferation markers. Results We identified nine splicing factors, including SNRPD2, SNRPD3 and NHP2L1, of which depletion inhibited proliferation in two TNBC cell lines by deregulation of sister chromatid cohesion (SCC) via increased sororin intron 1 retention and down-regulation of SMC1, MAU2 and ESPL1. Protein-protein interaction analysis of SNRPD2, SNRPD3 and NHP2L1 identified that seven out of the nine identified splicing factors belong to the same spliceosome complex including novel component SUN2 that was also critical for efficient sororin splicing. Finally, sororin transcript levels are highly correlated to various proliferation markers in BC patients. Conclusion We systematically determined splicing factors that control proliferation of breast cancer cells through a mechanism that involves effective sororin splicing and thereby appropriate sister chromatid cohesion. Moreover, we identified SUN2 as an important new spliceosome complex interacting protein that is critical in this process. We anticipate that deregulating sororin levels through targeting of the relevant splicing factors might be a potential strategy to treat TNBC.

Breast Cancer ◽  
2021 ◽  
Author(s):  
Yingzi Zhang ◽  
Jiao Tian ◽  
Chi Qu ◽  
Yang Peng ◽  
Jinwei Lei ◽  
...  

Abstract Background Recent studies have indicated that serpin peptidase inhibitor, clade A, member 3 (SERPINA3) is a potential marker associated with tumor progression, which connoted that SERPINA3 is related to malignant phenotypes in cancer. However, the biological function of SERPINA3 in breast cancer (BC) remains unclear. Methods Bioinformatics data were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Immunohistochemical staining (IHC) was conducted to determine SERPINA3 expression. With strong aggressive abilities, triple-negative breast cancer (TNBC) cell lines (MDA-MB-231, BT549 and MDA-MB-436) were obtained to examine SERPINA3 expression and functions. Wound healing and Transwell assays were performed to measure cell migration and invasion. Cell Counting Kit-8 (CCK-8) assay was conducted to detect cell proliferation abilities and cell viabilities. Results SERPINA3 was upregulated in BC tissues. Functional assays suggested that overexpression of SERPINA3 significantly promoted cell proliferation, where migration and invasion of TNBC cells were accelerated. Knockdown of SERPINA3 had the opposite effects. These results causing by overexpression of SERPINA3 were also confirmed in non-TNBC cell lines. Overexpression of SERPINA3 remarkably enhanced the epithelial–mesenchymal transition (EMT) by upregulating the EMT markers and EZH2. In addition, the overexpression of SERPINA3 reduced the sensitivity of TNBC cells to cisplatin. Conclusion SERPINA3 can regulate the migration, invasion and EMT of TNBC cells and increased expression of SERPINA3 confers resistance to cisplatin in TNBC cells. We discern it is required for the regulation of BC progression and is a critical target for the clinical treatment of BC.


2020 ◽  
Vol 21 (3) ◽  
pp. 903 ◽  
Author(s):  
Saioa Mendaza ◽  
Ane Ulazia-Garmendia ◽  
Iñaki Monreal-Santesteban ◽  
Alicia Córdoba ◽  
Yerani Ruiz de Azúa ◽  
...  

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype and currently lacks any effective targeted therapy. Since epigenetic alterations are a common event in TNBC, DNA methylation profiling can be useful for identifying potential biomarkers and therapeutic targets. Here, genome-wide DNA methylation from eight TNBC and six non-neoplastic tissues was analysed using Illumina Human Methylation 450K BeadChip. Results were validated by pyrosequencing in an independent cohort of 50 TNBC and 24 non-neoplastic samples, where protein expression was also assessed by immunohistochemistry. The functional role of disintegrin and metalloproteinase domain-containing protein 12(ADAM12) in TNBC cell proliferation, migration and drug response was analysed by gene expression silencing with short hairpin RNA. Three genes (Von Willenbrand factor C and Epidermal Growth Factor domain-containing protein (VWCE), tetraspanin-9 (TSPAN9) and ADAM12) were found to be exclusively hypomethylated in TNBC. Furthermore, ADAM12 hypomethylation was associated with a worse outcome in TNBC tissues and was also found in adjacent-to-tumour tissue and, preliminarily, in plasma from TNBC patients. In addition, ADAM12 silencing decreased TNBC cell proliferation and migration and improved doxorubicin sensitivity in TNBC cells. Our results indicate that ADAM12 is a potential therapeutic target and its hypomethylation could be a poor outcome biomarker in TNBC.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jintao Qian ◽  
Xinhan Lei ◽  
Yue Sun ◽  
Lu Zheng ◽  
Jia Li ◽  
...  

Abstract Background Growing evidence has demonstrated that long non-coding RNAs (lncRNAs) can function as modulators in the development of triple-negative breast cancer (TNBC). However, the function of lncRNA small nucleolar RNA host gene 8 (SNHG8) in TNBC remains unclear. Therefore, our study aimed at investigating the role of SNHG8 in the proliferation and migration of TNBC cells. Methods SNHG8 expression was evaluated using RT-qPCR assay. Cell proliferation and migration were assessed by EdU, colony formation and Transwell assays. The levels of proteins related to EMT process were examined by western blot assay. The interaction among SNHG8, miR-335-5p and pygopus family PHD finger 2 (PYGO2) was detected by RIP assay, RNA pull down assay and luciferase reporter assay. Results SNHG8 expression was significantly up-regulated in TNBC cells. SNHG8 silencing obviously inhibited TNBC cell proliferation, migration and EMT process. Moreover, SNHG8 acted as a sponge to sequester miR-335-5p in TNBC cells. Besides, PYGO2 was proven as a target gene of miR-335-5p, and SNHG8 promoted TNBC cell proliferation, migration and EMT process through regulating miR-335-5p and PYGO2. Conclusions Totally, our study indicated that SNHG8 promoted TNBC cell proliferation and migration by regulating the miR-335-5p/PYGO2 axis.


2020 ◽  
pp. 096032712097902
Author(s):  
Lining Wei ◽  
Xiangping Wang ◽  
Min Luo ◽  
Hongzhi Wang ◽  
Hao Chen ◽  
...  

Triple-negative breast cancer (TNBC) accounts for approximately 10–20% of all breast cancers and is one of the leading causes of mortality among females. Radiotherapy is essential during the treatment of breast cancer. Growing evidence has indicated that peptidyl arginine deiminase-4 (PAD4) inhibitor can alleviate the development of multiple cancers, including breast cancer, through inhibiting cell proliferation. GSK484 is considered to be a highly potent PAD4-selective inhibitors. However, the potential role and mechanism of GSK484 in TNBC remain unclear. In this study, we intended to explore the effects of GSK484 on the radiosensitivity of TNBC cell lines (MDA-MB-231 and BT-549). We found that the pretreatment of GSK484 enhanced irradiation (IR)-induced inhibitory effects on cell proliferation, migration and invasion. Besides, our findings revealed that GSK484 facilitated TNBC cell apoptosis. IR treatment-induced increase of the protein level of ATG5 and ATG7, and decrease of p62 protein level were countervailed by GSK484. In addition, GSK484 enhanced DNA damage induced by IR. Moreover, in vivo experiments demonstrated that the combined treatment of IR and GSK484 showed an obvious decline of tumor growth in contrast to IR-alone or GSK484-alone treatment. Overall, GSK484 may serve as a radiosensitizer of TNBC through inhibiting IR-induced autophagy.


2021 ◽  
Author(s):  
Hao Sun ◽  
Hongjun Huo ◽  
Xiaoyan Hao ◽  
Juanyun Li ◽  
Zishan Yuan

Abstract BackgroundAlthought lncRNA SEMA3B-AS1 was known to be involved in the development of many types of cancer, the role of SEMA3B-AS1 in triple-negative breast cancer (TNBC) remains unknown. This study was to investigate the role and underlying mechanism of SEMA3B-AS1 in TNBC.The mRNA expression of SEMA3B-AS1, miR-545 and CDK4 in TNBC tissues and non-cancer tissues of TNBC patients (n = 69) was detected by RT-qPCR. The protein expression of CDK4 was detected by Western blot. Cell proliferation were evaluated by CCK-8 assay.ResultsWe found that the expression of SEMA3B-AS1 was downregulated in TNBC tissues. The expression of SEMA3B-AS1 was positively correlated with the expression of miR-545 and inversely correlated with the expression of CDK4. Overexpression of SEMA3B-AS1 or miR-545 resulted in the downregulation of CDK4. Moreover, miR-545 inhibitor attenuated the effect of SEMA3B-AS1 overexpression on CDK4 expression. SEMA3B-AS1 overexpression also resulted in the upregulation of miR-545. Overexpression of SEMA3B-AS1 or miR-545 decreased the rate of TNBC cell proliferation, while overexpression of CDK4 increased the rate of TNBC cell proliferation. In addition, miR-545 inhibitor attenuated the effect of SEMA3B-AS1 overexpression on cell proliferation.Interaction between SEMA3B-AS1 and CDK4 mediated by miR-545 regulates the proliferation of TNBC cells.


2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Sugang Ma ◽  
Hui Wei ◽  
Chunyan Wang ◽  
Jixia Han ◽  
Xiumin Chen ◽  
...  

Abstract Background The study was designed to elucidate the association and functional roles of miR-26b-5p and c-MYC binding protein (MYCBP) in triple-negative breast cancer (TNBC). Method Luciferase reporter assay was used to confirm the relationship between miR-26b-5p and MYCBP in TNBC cells. The expression levels of miR-26b-5p and MYCBP in tissue specimens and cell lines were determined using reverse transcription-quantitative PCR. Cell proliferation, migration and invasion were assessed using CCK-8 assay, colony formation and transwell assay. Results We first observed that miR-26b-5p directly targets the 3′-UTR of MYCBP to inhibit MYCBP expression in MDA-MB-468 and BT-549 cells. The expression of miR-26b-5p was inversely correlated with MYCBP expression in TNBC tissues. We further demonstrated that MYCBP knockdown suppressed the proliferation, migration and invasion of TNBC cells. Furthermore, MYCBP overexpression counteracted the suppressive effect of miR-26b-5p on TNBC cell behaviors. Western blot analysis demonstrated that the E-cadherin protein level was increased, while protein levels of N-cadherin and vimentin were decreased in cells transfected with miR-26b-5p, which were all reversed by ectopic expression of MYCBP. Conclusions In summary, our findings revealed the tumor suppressive role of miR-26b-5p in regulating TNBC cell proliferation and mobility, possibly by targeting MYCBP.


2020 ◽  
Author(s):  
Di Wu ◽  
Hongyao Jia ◽  
Zhiru Zhang ◽  
Sijie Li

Abstract Background: Currently, long non-coding RNAs (lncRNAs) have been validated to exert critical influence on the malignant progression of triple-negative breast cancer (TNBC). LncRNA long intergenic non-protein coding RNA 504 (LINC00504) has been recently reported as a tumor facilitator in the cellular processes of several cancers. However, its function in TNBC remains unknown.Methods: CCK-8 and colony formation assays were used to detect the cell viability and proliferation in TNBC. Flow cytometry analysis was utilized to measure the cycle and apoptosis of TNBC cells. The levels of key proteins associated with cell apoptosis or the β-catenin pathway were detected through western blot analysis. The activity of the Wnt/β-catenin signaling pathway was measured by the TOP/FOP flash assay. ChIP assay was conducted to confirm the binding between LINC00504 and its transcription factor signal transducer and activator of transcription 3 (STAT3). RIP and luciferase reporter assays were used to detect and verify the interaction among LINC00504 and its downstream molecule.Results: LncRNA LINC00504 was upregulated in TNBC, and silenced LINC00504 suppressed cell proliferation and triggers cell cycle arrest at G0/G1 stage and cell apoptosis in TNBC cells. STAT3 can transcriptionally activate LINC00504 and LINC00504 served as a molecular sponge of microRNA (miR-4379). Kallikrein related peptidase 4 (KLK4) was the target gene of miR-4379 and activates the Wnt/β-catenin pathway. LINC00504 upregulated KLK4 via competitively binding with miR-4379 to activate the Wnt/β-catenin pathway in TNBC. The suppression on TNBC cell proliferation and the promotion on TNBC cell cycle arrest and apoptosis under LINC00504 knockdown were rescued by miR-4379 depletion or KLK4 overexpression.Conclusions: The LINC00504/miR-4379/KLK4 axis promotes cell growth and cell cycle progression as well as suppresses cell apoptosis through activating the Wnt/β-catenin pathway.


2017 ◽  
Vol 26 (3) ◽  
pp. 178-82 ◽  
Author(s):  
Bantari W.K. Wardhani ◽  
Meidi U. Puteri ◽  
Yukihide Watanabe ◽  
Melva Louisa ◽  
Rianto Setiabudy ◽  
...  

Background: Triple negative breast cancer (TNBC) tends to grow more rapidly and has poorer prognosis compared to others. High expression of transmembrane prostate androgen-induced protein (TMEPAI) correlates with poor prognosis in TNBC patients. However, the mechanistic role of TMEPAI in tumorigenic remains unknown. This study aimed to knock-out TMEPAI in TNBC cell line to determine its function further in cells proliferation.Methods: CRISPR-Cas9 has been used previously to knock-out TMEPAI in Hs857T TNBC cell line. Hs587T TNBC parental cell line (wild-type/WT) and TMEPAI knock out Hs 586T cell lines were cultured in Dulbecco’s modified eagle medium (DMEM) supplemented with 10% fetal bovine serum, 1% penicillin-streptomycin and amphotericin B. Both cell lines were seeded in 24-well plates and counted every two days, then proliferation rates were plotted. Afterwards, total RNA were isolated from the cells and Ki-67, and TGF-β mRNA expression levels as proliferation markers were determined.Results: Cell proliferation rates as displayed in growth curve plots showed that WT-TMEPAI cell line grew more rapidly than KO-TMEPAI. In accordance, mRNA expression levels of  Ki-67 and TGF-β  were significantly decreased KO-TMEPAI as compare to TMEPAI-WT.Conclusion: Knock-out of TMEPAI attenuates cell proliferation in TNBC.


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