scholarly journals Fusion Transcripts of Adjacent Genes: New Insights into the World of Human Complex Transcripts in Cancer

2019 ◽  
Vol 20 (21) ◽  
pp. 5252 ◽  
Author(s):  
Vincenza Barresi ◽  
Ilaria Cosentini ◽  
Chiara Scuderi ◽  
Salvatore Napoli ◽  
Virginia Di Bella ◽  
...  

The awareness of genome complexity brought a radical approach to the study of transcriptome, opening eyes to single RNAs generated from two or more adjacent genes according to the present consensus. This kind of transcript was thought to originate only from chromosomal rearrangements, but the discovery of readthrough transcription opens the doors to a new world of fusion RNAs. In the last years many possible intergenic cis-splicing mechanisms have been proposed, unveiling the origins of transcripts that contain some exons of both the upstream and downstream genes. In some cases, alternative mechanisms, such as trans-splicing and transcriptional slippage, have been proposed. Five databases, containing validated and predicted Fusion Transcripts of Adjacent Genes (FuTAGs), are available for the scientific community. A comparative analysis revealed that two of them contain the majority of the results. A complete analysis of the more widely characterized FuTAGs is provided in this review, including their expression pattern in normal tissues and in cancer. Gene structure, intergenic splicing patterns and exon junction sequences have been determined and here reported for well-characterized FuTAGs. The available functional data and the possible roles in cancer progression are discussed.

2021 ◽  
Vol 22 (22) ◽  
pp. 12178
Author(s):  
Bijay P. Dhungel ◽  
Geoffray Monteuuis ◽  
Caroline Giardina ◽  
Mehdi S. Tabar ◽  
Yue Feng ◽  
...  

Chimeric RNAs are often associated with chromosomal rearrangements in cancer. In addition, they are also widely detected in normal tissues, contributing to transcriptomic complexity. Despite their prevalence, little is known about the characteristics and functions of chimeric RNAs. Here, we examine the genetic structure and biological roles of CLEC12A-MIR223HG, a novel chimeric transcript produced by the fusion of the cell surface receptor CLEC12A and the miRNA-223 host gene (MIR223HG), first identified in chronic myeloid leukemia (CML) patients. Surprisingly, we observed that CLEC12A-MIR223HG is not just expressed in CML, but also in a variety of normal tissues and cell lines. CLEC12A-MIR223HG expression is elevated in pro-monocytic cells resistant to chemotherapy and during monocyte-to-macrophage differentiation. We observed that CLEC12A-MIR223HG is a product of trans-splicing rather than a chromosomal rearrangement and that transcriptional activation of CLEC12A with the CRISPR/Cas9 Synergistic Activation Mediator (SAM) system increases CLEC12A-MIR223HG expression. CLEC12A-MIR223HG translates into a chimeric protein, which largely resembles CLEC12A but harbours an altered C-type lectin domain altering key disulphide bonds. These alterations result in differences in post-translational modifications, cellular localization, and protein–protein interactions. Taken together, our observations support a possible involvement of CLEC12A-MIR223HG in the regulation of CLEC12A function. Our workflow also serves as a template to study other uncharacterized chimeric RNAs.


2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Dawei Chen ◽  
Zhenguo Zhao ◽  
Lu Chen ◽  
Qinghua Li ◽  
Jixue Zou ◽  
...  

AbstractEmerging evidence has demonstrated that alternative splicing has a vital role in regulating protein function, but how alternative splicing factors can be regulated remains unclear. We showed that the PPM1G, a protein phosphatase, regulated the phosphorylation of SRSF3 in hepatocellular carcinoma (HCC) and contributed to the proliferation, invasion, and metastasis of HCC. PPM1G was highly expressed in HCC tissues compared to adjacent normal tissues, and higher levels of PPM1G were observed in adverse staged HCCs. The higher levels of PPM1G were highly correlated with poor prognosis, which was further validated in the TCGA cohort. The knockdown of PPM1G inhibited the cell growth and invasion of HCC cell lines. Further studies showed that the knockdown of PPM1G inhibited tumor growth in vivo. The mechanistic analysis showed that the PPM1G interacted with proteins related to alternative splicing, including SRSF3. Overexpression of PPM1G promoted the dephosphorylation of SRSF3 and changed the alternative splicing patterns of genes related to the cell cycle, the transcriptional regulation in HCC cells. In addition, we also demonstrated that the promoter of PPM1G was activated by multiple transcription factors and co-activators, including MYC/MAX and EP300, MED1, and ELF1. Our study highlighted the essential role of PPM1G in HCC and shed new light on unveiling the regulation of alternative splicing in malignant transformation.


Author(s):  
Mingyi Zhou ◽  
Zhuo Yang ◽  
Danbo Wang ◽  
Peng Chen ◽  
Yong Zhang

Abstract Background As a novel type of non-coding RNA, circular RNAs (circRNAs) play a critical role in the initiation and development of various diseases, including cancer. However, the exact function of circRNAs in human cervical cancer remains largely unknown. Methods We identified the circRNA signature of upregulated circRNAs between cervical cancer and paired adjacent normal tissues. Using two different cohorts and GEO database, a total of six upregulated circRNAs were identified with a fold change > 2, and P < 0.05. Among these six circRNAs, hsa_circ_0072088 (circZFR) was the only exonic circRNA significantly overexpressed in cervical cancer. Functional experiments were performed to investigate the biological function of circZFR. CircRNA pull-down, circRNA immunoprecipitation (circRIP) and Co-immunoprecipitation (Co-IP) assays were executed to investigate the molecular mechanism underlying the function of circZFR. Results Functionally, circZFR knockdown represses the proliferation, invasion, and tumor growth. Furthermore, circRNA pull-down experiments combined with mass spectrometry unveil the interactions of circZFR with Single-Stranded DNA Binding Protein 1 (SSBP1). Mechanistically, circZFR bound with SSBP1, thereby promoting the assembly of CDK2/cyclin E1 complexes. The activation of CDK2/cyclin E1 complexes induced p-Rb phosphorylation, thus releasing activated E2F1 leading to cell cycle progression and cell proliferation. Conclusion Our findings provide the first evidence that circZFR is a novel onco-circRNA and might be a potential biomarker and therapeutic target for cervical cancer patients.


2021 ◽  
Vol 10 ◽  
Author(s):  
Wenhua Xu ◽  
Wenna Yang ◽  
Chunfeng Wu ◽  
Xiaocong Ma ◽  
Haoyu Li ◽  
...  

Enolase 1 (ENO1) is an oxidative stress protein expressed in endothelial cells. This study aimed to investigate the correlation of ENO1 with prognosis, tumor stage, and levels of tumor-infiltrating immune cells in multiple cancers. ENO1 expression and its influence on tumor stage and clinical prognosis were analyzed by UCSC Xena browser, Gene Expression Profiling Interactive Analysis (GEPIA), The Cancer Genome Atlas (TCGA), and GTEx Portal. The ENO1 mutation analysis was performed by cBio Portal, and demonstrated ENO1 mutation (1.8%) did not impact on tumor prognosis. The relationship between ENO1 expression and tumor immunity was analyzed by Tumor Immune Estimation Resource (TIMER) and GEPIA. The potential functions of ENO1 in pathways were investigated by Gene Set Enrichment Analysis. ENO1 expression was significantly different in tumor and corresponding normal tissues. ENO1 expression in multiple tumor tissues correlated with prognosis and stage. ENO1 showed correlation with immune infiltrates including B cells, CD8+ and CD4+ T cells, macrophages, neutrophils, and dendritic cells, and tumor purity. ENO1 was proved to be involved in DNA replication, cell cycle, apoptosis, glycolysis process, and other processes. These findings indicate that ENO1 is a potential prognostic biomarker that correlates with cancer progression immune infiltration.


2020 ◽  
pp. 1-8
Author(s):  
Yunfeng Zhao ◽  
Cherie Ann Nathan ◽  
Chunjing Zhang ◽  
Hongyan Du ◽  
Manikandan Panchatcharam ◽  
...  

Background: New adjuvant therapies for human head and neck (H&N) cancer to improve the quality of life of the patients are in great demand. Our early studies have demonstrated that uncoupling protein 2 (UCP2) is upregulated in the tumor tissues of H&N cancer compared to the adjacent normal tissues; however, the role of UCP2 in H&N cancer has not been studied. Objective: In this manuscript, we aim to examine whether UCP2 contributes to H&N cancer progression in vitro. Methods: We generated UCP2 stable knockdown H&N cancer cells and detected the effects of UCP2 inhibition on cell proliferation, migration, invasion, 3D spheroid formation, and the sensitivity to a chemodrug treatment. Results: Knockdown of UCP2 suppressed the progression of H&N cancer in vitro, which might be mediated via the following mechanism: 1) increased the G1 phase whereas decreased the S phase of the cell cycle, which could be mediated by suppression of the G1/S regulators including CDK4/6 and cyclin D1. 2) Decreased mitochondrial oxygen consumption, ATP production, and lactate formation, which is consistent with the downregulation of c-Myc. 3) FAK may serve as the upstream signaling molecule, and its action was mediated by Akt and ERK. Conclusions: Our studies first demonstrate that targeting UCP2 may suppress H&N cancer progression in vitro.


2021 ◽  
Vol 11 (9) ◽  
pp. 1707-1713
Author(s):  
Jun Wan ◽  
Jian Wang ◽  
Qiurong Huang ◽  
Guanggui Ding ◽  
Xiean Ling

Lung cancer is a most common cancer worldwide. Tumor-associated macrophage (TAM) is known a key effector cell in tumor microenvironment. Meanwhile, STAT6 is crucial to cancer development. We aimed to determine the interaction between STAT6 and TAMs in lung cancer. In this work, firstly, we established mouse model of lung cancer. Then, immunofluorescence was performed to determine STAT6 and CD206 level in lung cancer tissue and adjacent normal tissues as well as model mice. RT-qPCR was applied to detect differentiation of macrophage and determine related gene expression. After treatment of siRNA of STAT6 or STAT6 inhibitor (AS1517499), Transwell assay and MTT were used to determine cell proliferation and migration. STAT6 was upregulated in lung cancer tissues while arginase was more active in M2 macrophage rather than M1 macrophage. Transfection of si-STAT6 not only decreased differentiation in M2 macrophage but also inhibited proliferative, migratory and invasive ability of cancer cells while AS1517499 led to reduced tumor growth. STAT6 inhibition caused decreased expression of M2 macrophages. Similarly, intratumoral T cell markers showed that CD8+T cell gene expression and CD4-mediated T cell marker FoxP3 was increased slightly. Taken altogether, macrophage-STAT6 promotes cell migration and proliferation in lung cancer.


2020 ◽  
Vol 35 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Mingzhu Lin ◽  
Yinyan Li ◽  
Jianfeng Xian ◽  
Jinbin Chen ◽  
Yingyi Feng ◽  
...  

Objective: Abundant evidence has illustrated that long non-coding RNA (lncRNA) plays a vital role in the regulation of tumor development and progression. Ectopic expression of a novel lncRNA, termed lnc-AGER-1, has been discovered in cancers, and this lncRNA was reported to exert an anti-tumor effect. However, its biological mechanism remains unelucidated in colorectal cancer. Methods: A total of 159 paired colorectal cancer specimens and adjacent tissues was applied to detect the expression of lnc-AGER-1 by the quantitative Real-time PCR (qRT-PCR), and a series of functional assays was executed to uncover the role of this lncRNA on colorectal cancer. Results: We found that the expression of lnc-AGER-1 in the tumor tissues was significantly down-regulated, while compared with adjacent normal tissues (0.0115 ± 0.0718 vs. 0.0347 ± 0.157; P < 0.0001). Also, lnc-AGER-1 was observably associated with clinical T status (r = −0.184, P = 0.024). Patients with advanced T status exerted a significantly lower level of lnc-AGER-1 than those with early T status (20.0% vs. 40.7%, P = 0.021). Over-expression of lnc-AGER-1 inhibited cell proliferation and migration efficiency, and induced cell cycle arrest at the G0/G1 phase, and promoted cell apoptosis. Further research proved that lnc-AGER-1 altered the expression of its neighbor gene, AGER, through acting as a competing endogenous RNA for miR-182 in colorectal cancer. Conclusion: lnc-AGER-1 has a suppressive role in colorectal cancer development via modulating AGER, which may serve as a target for colorectal cancer diagnosis and treatment.


BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Yi Hu ◽  
Yan Ma ◽  
Jie Liu ◽  
Yanlin Cai ◽  
Mengmeng Zhang ◽  
...  

Abstract Background Cervical cancer (CC), causing significant morbidity and mortality worldwide, is one of the most common gynecological malignancies in women. SFN has been reported as a potential prognostic marker with apparent high expression in tumors. Nevertheless, the function mechanism of SFN is not clear yet in CC. Methods The relative expressions of RNAs were detected by real-time quantitative PCR (RT-qPCR). Colony formation assay, EdU stained assay and CCK-8 assay were to check cell proliferation ability in CC. Flow cytometry and apoptosis related proteins analysis were used to measure cells apoptosis capacity. Luciferase reporter assay and RNA pull down assay were to verify the molecular mechanism. Results SFN was highly expressed in CC tissues and CC cell lines compared with normal tissues and normal cell line. After interfering SFN, cell proliferation, migration and invasion ability was inhibited as well as cell apoptosis ability was promoted. In subsequence, miR-383-5p exhibited conspicuous low expression in CC tissues. And miR-383-5p was found to bind to SFN and have anti-cancerous effects in CC. Moreover, LINC01128 displayed remarkable high expression in CC tissues. Besides, LINC01128 shortage could reduce the expression of SFN at mRNA and protein levels. And the affinity between LINC01128 and miR-383-5p was verified. In the end, it was proved that LINC01128 could enhance cell proliferation, migration and invasion as well as inhibit cell apoptosis by binding with miR-383-5p and upregulating SFN. Conclusion LINC01128 expedited cells cellular process in CC by binding with miR-383-5p to release SFN. Graphical Abstract


2019 ◽  
Vol 48 (4) ◽  
pp. 1886-1904 ◽  
Author(s):  
Jihane Basbous ◽  
Antoine Aze ◽  
Laurent Chaloin ◽  
Rana Lebdy ◽  
Dana Hodroj ◽  
...  

Abstract Imbalance in the level of the pyrimidine degradation products dihydrouracil and dihydrothymine is associated with cellular transformation and cancer progression. Dihydropyrimidines are degraded by dihydropyrimidinase (DHP), a zinc metalloenzyme that is upregulated in solid tumors but not in the corresponding normal tissues. How dihydropyrimidine metabolites affect cellular phenotypes remains elusive. Here we show that the accumulation of dihydropyrimidines induces the formation of DNA–protein crosslinks (DPCs) and causes DNA replication and transcriptional stress. We used Xenopus egg extracts to recapitulate DNA replication invitro. We found that dihydropyrimidines interfere directly with the replication of both plasmid and chromosomal DNA. Furthermore, we show that the plant flavonoid dihydromyricetin inhibits human DHP activity. Cellular exposure to dihydromyricetin triggered DPCs-dependent DNA replication stress in cancer cells. This study defines dihydropyrimidines as potentially cytotoxic metabolites that may offer an opportunity for therapeutic-targeting of DHP activity in solid tumors.


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