scholarly journals Alternative splicing in neuroblastoma generates RNA-fusion transcripts and is associated with vulnerability to spliceosome inhibitors

2019 ◽  
Author(s):  
Yao Shi ◽  
Vilma Rraklli ◽  
Eva Maxymovitz ◽  
Shuijie Li ◽  
Isabelle Westerlund ◽  
...  

AbstractThe paucity of recurrent mutations has hampered efforts to understand and treat neuroblastoma. Alternative splicing and splicing-dependent RNA-fusions represent mechanisms able to increase the gene product repertoire but their role in neuroblastoma remains largely unexplored. Through analysis of RNA-sequenced neuroblastoma we here show that elevated expression of splicing factors is a strong predictor of poor clinical outcome. Furthermore, we identified >900 primarily intrachromosomal fusions containing canonical splicing sites. Fusions included transcripts from well-known oncogenes, were enriched for proximal genes and in chromosomal regions commonly gained or lost in neuroblastoma. As a proof-of-principle that these fusions can generate altered gene products, we characterized a ZNF451-BAG2 fusion, generating a truncated BAG2-protein which inhibited retinoic acid-induced differentiation. Spliceosome inhibition impeded neuroblastoma fusion expression, induced apoptosis and inhibited xenograft tumor growth. Our findings elucidate a splicing-dependent mechanism producing altered gene products in neuroblastoma and suggest that the spliceosome is a tractable therapeutical target.

2021 ◽  
Author(s):  
Yao Shi ◽  
Juan Yuan ◽  
Vilma Rraklli ◽  
Eva Maxymovitz ◽  
Miriam Cipullo ◽  
...  

Abstract The paucity of recurrent mutations has hampered efforts to understand and treat neuroblastoma. Alternative splicing and splicing-dependent RNA-fusions represent mechanisms able to increase the gene product repertoire but their role in neuroblastoma remains largely unexplored. Here we investigate the presence and possible roles of aberrant splicing and splicing-dependent RNA-fusion transcripts in neuroblastoma. In addition, we attend to establish whether the spliceosome can be targeted to treat neuroblastoma. Through analysis of RNA-sequenced neuroblastoma we show that elevated expression of splicing factors is a strong predictor of poor clinical outcome. Furthermore, we identified >900 primarily intrachromosomal fusions containing canonical splicing sites. Fusions included transcripts from well-known oncogenes, were enriched for proximal genes and in chromosomal regions commonly gained or lost in neuroblastoma. As a proof-of-principle that these fusions can generate altered gene products, we characterized a ZNF451-BAG2 fusion, producing a truncated BAG2-protein which inhibited retinoic acid induced differentiation. Spliceosome inhibition impeded neuroblastoma fusion expression, induced apoptosis and inhibited xenograft tumor growth. Our findings elucidate a splicing-dependent mechanism generating altered gene products in neuroblastoma and show that the spliceosome is a potential target for clinical intervention.


1992 ◽  
Vol 267 (10) ◽  
pp. 7139-7147
Author(s):  
D.M. Rothstein ◽  
H Saito ◽  
M Streuli ◽  
S.F. Schlossman ◽  
C Morimoto

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yan Ouyang ◽  
Kaide Xia ◽  
Xue Yang ◽  
Shichao Zhang ◽  
Li Wang ◽  
...  

AbstractAlternative splicing (AS) events associated with oncogenic processes present anomalous perturbations in many cancers, including ovarian carcinoma. There are no reliable features to predict survival outcomes for ovarian cancer patients. In this study, comprehensive profiling of AS events was conducted by integrating AS data and clinical information of ovarian serous cystadenocarcinoma (OV). Survival-related AS events were identified by Univariate Cox regression analysis. Then, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis were used to construct the prognostic signatures within each AS type. Furthermore, we established a splicing-related network to reveal the potential regulatory mechanisms between splicing factors and candidate AS events. A total of 730 AS events were identified as survival-associated splicing events, and the final prognostic signature based on all seven types of AS events could serve as an independent prognostic indicator and had powerful efficiency in distinguishing patient outcomes. In addition, survival-related AS events might be involved in tumor-related pathways including base excision repair and pyrimidine metabolism pathways, and some splicing factors might be correlated with prognosis-related AS events, including SPEN, SF3B5, RNPC3, LUC7L3, SRSF11 and PRPF38B. Our study constructs an independent prognostic signature for predicting ovarian cancer patients’ survival outcome and contributes to elucidating the underlying mechanism of AS in tumor development.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 130
Author(s):  
Flavia Zita Francies ◽  
Sheynaz Bassa ◽  
Aristotelis Chatziioannou ◽  
Andreas Martin Kaufmann ◽  
Zodwa Dlamini

Gynaecological cancers are attributed to the second most diagnosed cancers in women after breast cancer. On a global scale, cervical cancer is the fourth most common cancer and the most common cancer in developing countries with rapidly increasing mortality rates. Human papillomavirus (HPV) infection is a major contributor to the disease. HPV infections cause prominent cellular changes including alternative splicing to drive malignant transformation. A fundamental characteristic attributed to cancer is the dysregulation of cellular transcription. Alternative splicing is regulated by several splicing factors and molecular changes in these factors lead to cancer mechanisms such as tumour development and progression and drug resistance. The serine/arginine-rich (SR) proteins and heterogeneous ribonucleoproteins (hnRNPs) have prominent roles in modulating alternative splicing. Evidence shows molecular alteration and expression levels in these splicing factors in cervical cancer. Furthermore, aberrant splicing events in cancer-related genes lead to chemo- and radioresistance. Identifying clinically relevant modifications in alternative splicing events and splicing variants, in cervical cancer, as potential biomarkers for their role in cancer progression and therapy resistance is scrutinised. This review will focus on the molecular mechanisms underlying the aberrant splicing events in cervical cancer that may serve as potential biomarkers for diagnosis, prognosis, and novel drug targets.


Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1517-1529 ◽  
Author(s):  
James M Burnette ◽  
Allyson R Hatton ◽  
A Javier Lopez

Abstract Alternatively spliced Ultrabithorax mRNAs differ by the presence of internal exons mI and mII. Two approaches were used to identify trans-acting factors required for inclusion of these cassette exons. First, mutations in a set of genes implicated in the control of other alternative splicing decisions were tested for dominant effects on the Ubx alternative splicing pattern. To identify additional genes involved in regulation of Ubx splicing, a large collection of deficiencies was tested first for dominant enhancement of the haploinsufficient Ubx haltere phenotype and second for effects on the splicing pattern. Inclusion of the cassette exons in Ubx mRNAs was reduced strongly in heterozygotes for hypomorphic alleles of hrp48, which encodes a member of the hnRNP A/B family and is implicated in control of P-element splicing. Significant reductions of mI and mII inclusion were also observed in heterozygotes for loss-of-function alleles of virilizer, fl(2)d, and crooked neck. The products of virilizer and fl(2)d are also required for Sxl autoregulation at the level of splicing; crooked neck encodes a protein with structural similarities to yeast-splicing factors Prp39p and Prp42p. Deletion of at least five other loci caused significant reductions in the inclusion of mI and/or mII. Possible roles of identified factors are discussed in the context of the resplicing strategy for generation of alternative Ubx mRNAs.


BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Pihua Han ◽  
Jingjun Zhu ◽  
Guang Feng ◽  
Zizhang Wang ◽  
Yanni Ding

Abstract Background Breast cancer (BRCA) is one of the most common cancers worldwide. Abnormal alternative splicing (AS) frequently observed in cancers. This study aims to demonstrate AS events and signatures that might serve as prognostic indicators for BRCA. Methods Original data for all seven types of splice events were obtained from TCGA SpliceSeq database. RNA-seq and clinical data of BRCA cohorts were downloaded from TCGA database. Survival-associated AS events in BRCA were analyzed by univariate COX proportional hazards regression model. Prognostic signatures were constructed for prognosis prediction in patients with BRCA based on survival-associated AS events. Pearson correlation analysis was performed to measure the correlation between the expression of splicing factors (SFs) and the percent spliced in (PSI) values of AS events. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were conducted to demonstrate pathways in which survival-associated AS event is enriched. Results A total of 45,421 AS events in 21,232 genes were identified. Among them, 1121 AS events in 931 genes significantly correlated with survival for BRCA. The established AS prognostic signatures of seven types could accurately predict BRCA prognosis. The comprehensive AS signature could serve as independent prognostic factor for BRCA. A SF-AS regulatory network was therefore established based on the correlation between the expression levels of SFs and PSI values of AS events. Conclusions This study revealed survival-associated AS events and signatures that may help predict the survival outcomes of patients with BRCA. Additionally, the constructed SF-AS networks in BRCA can reveal the underlying regulatory mechanisms in BRCA.


2021 ◽  
Vol 8 ◽  
Author(s):  
Ingmar Rieger ◽  
Vasileia Tsintari ◽  
Mathis Overkamp ◽  
Falko Fend ◽  
Charles D. Lopez ◽  
...  

Alternative splicing is a common physiologic mechanism to generate numerous distinct gene products from one gene locus, which can result in unique gene products with differing important functional outcomes depending on cell context. Aberrant alternative splicing is a hallmark of cancer that can contribute to oncogenesis and aggressiveness of the disease as well as resistance to therapy. However, aberrant splicing might also result in novel targets for cancer therapy. ASPP2 is a haplo-insufficient tumor suppressor, that functions through both p53-dependent as well as p53-independent mechanisms to enhance cell death after stress. Interestingly, the common human tumor TP53 mutations result in a loss of the binding sites to ASPP2, leading to impaired induction of apoptosis. Vice versa, attenuation of ASPP2 has been described to be associated with high-risk disease, therapy failure and poor clinical outcome especially in tumors harboring the TP53 wildtype (WT) isoform. We have recently identified a novel, dominant-negative splicing variant of ASPP2, named ASPP2κ, with oncogenic potential. Exon-skipping results in a reading-frame shift with a premature translation stop, omitting most of the ASPP2 C-terminus - which harbors the p53-binding domain. Consequently, the ASPP2-p53 interaction is abrogated, which in part impacts on oncogenesis, aggressiveness of disease and response to therapy. Since ASPP2κ has been shown in hematologic malignancies to promote tumorigenesis, we further wished to determine if aberrant ASPP2κ expression plays a role in human solid tumors. In this report, we find that ASPP2κ is frequently expressed in human colorectal tumors (CRC). Using ASPP2κ overexpressing and interference CRC models, we demonstrate a functional role of ASPP2κ in contributing to oncogenesis and resistance to therapy in CRC by 1) enhancing proliferation, 2) promoting cell migration and, 3) conferring resistance to chemotherapy induced apoptosis. Our findings have far-reaching consequences for future diagnostic and therapeutic strategies for ASPP2κ expressing colorectal cancer patients and provide proof-of-principle to further explore ASPP2κ as potential predictive marker and target for therapy in clinical trials.


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