scholarly journals ASPP2κ Is Expressed In Human Colorectal Carcinoma And Promotes Chemotherapy Resistance And Tumorigenesis

2021 ◽  
Vol 8 ◽  
Author(s):  
Ingmar Rieger ◽  
Vasileia Tsintari ◽  
Mathis Overkamp ◽  
Falko Fend ◽  
Charles D. Lopez ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Chemotherapy Resistance ◽  
Human Tumor ◽  
Exon Skipping ◽  
Predictive Marker ◽  
Hematologic Malignancies ◽  
Response To Therapy ◽  
Dominant Negative ◽  
Gene Products ◽  
Resistance To Therapy

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.

scholarly journals Thioredoxin Reductase Mediates Cell Death Effects of the Combination of Beta Interferon and Retinoic Acid

1998 ◽  
Vol 18 (11) ◽  
pp. 6493-6504 ◽  
Author(s):  
Edward R. Hofman ◽  
Madanamohan Boyanapalli ◽  
Daniel J. Lindner ◽  
Xiao Weihua ◽  
Bret A. Hassel ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinoic Acid ◽  
Cell Growth ◽  
Growth Regulation ◽  
Growth Promotion ◽  
Thioredoxin Reductase ◽  
Human Tumor ◽  
Dominant Negative ◽  
Gene Products

ABSTRACT Interferons (IFNs) and retinoids are potent biological response modifiers. By using JAK-STAT pathways, IFNs regulate the expression of genes involved in antiviral, antitumor, and immunomodulatory actions. Retinoids exert their cell growth-regulatory effects via nuclear receptors, which also function as transcription factors. Although these ligands act through distinct mechanisms, several studies have shown that the combination of IFNs and retinoids synergistically inhibits cell growth. We have previously reported that IFN-β–all-trans-retinoic acid (RA) combination is a more potent growth suppressor of human tumor xenografts in vivo than either agent alone. Furthermore, the IFN-RA combination causes cell death in several tumor cell lines in vitro. However, the molecular basis for these growth-suppressive actions is unknown. It has been suggested that certain gene products, which mediate the antiviral actions of IFNs, are also responsible for the antitumor actions of the IFN-RA combination. However, we did not find a correlation between their activities and cell death. Therefore, we have used an antisense knockout approach to directly identify the gene products that mediate cell death and have isolated several genes associated with retinoid-IFN-induced mortality (GRIM). In this investigation, we characterized one of the GRIM cDNAs, GRIM-12. Sequence analysis suggests that the GRIM-12 product is identical to human thioredoxin reductase (TR). TR is posttranscriptionally induced by the IFN-RA combination in human breast carcinoma cells. Overexpression of GRIM-12 causes a small amount of cell death and further enhances the susceptibility of cells to IFN-RA-induced death. Dominant negative inhibitors directed against TR inhibit its cell death-inducing functions. Interference with TR enzymatic activity led to growth promotion in the presence of the IFN-RA combination. Thus, these studies identify a novel function for TR in cell growth regulation.

Expression of RHD and RHCE gene products using retroviral transduction of K562 cells establishes the molecular basis of Rh blood group antigens

Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2968-2973 ◽  
Author(s):  
JS Smythe ◽  
ND Avent ◽  
PA Judson ◽  
SF Parsons ◽  
PG Martin ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Gene Transfer ◽  
Molecular Basis ◽  
Exon Skipping ◽  
K562 Cells ◽  
Blood Group Antigens ◽  
Gene Products ◽  
Retroviral Transduction ◽  
Direct Demonstration ◽  
Rh Blood Group

Retroviral-mediated gene transfer using cDNA transcripts of the RHD and RHCE genes resulted in the isolation of K562 clones expressing D and G or c and E antigens, respectively. These results represent the first direct demonstration that the RHD gene encodes the D and G antigens and the RHCE gene encodes the c and E antigens. Both c and E antigens were expressed after transduction of K562 cells with a single cDNA, indicating that the c antigen does not arise by alternative splicing (exon skipping) of the product of the RHCE gene, as has been suggested.

scholarly journals Alternative splicing landscapes in Arabidopsis thaliana across tissues and stress conditions highlight major functional differences with animals

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Guiomar Martín ◽  
Yamile Márquez ◽  
Federica Mantica ◽  
Paula Duque ◽  
Manuel Irimia
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Alternative Splicing ◽  
Stress Responses ◽  
Target Genes ◽  
Intron Retention ◽  
Single Gene ◽  
Exon Skipping ◽  
Environmental Response ◽  
Biotic Stresses

Abstract Background Alternative splicing (AS) is a widespread regulatory mechanism in multicellular organisms. Numerous transcriptomic and single-gene studies in plants have investigated AS in response to specific conditions, especially environmental stress, unveiling substantial amounts of intron retention that modulate gene expression. However, a comprehensive study contrasting stress-response and tissue-specific AS patterns and directly comparing them with those of animal models is still missing. Results We generate a massive resource for Arabidopsis thaliana, PastDB, comprising AS and gene expression quantifications across tissues, development and environmental conditions, including abiotic and biotic stresses. Harmonized analysis of these datasets reveals that A. thaliana shows high levels of AS, similar to fruitflies, and that, compared to animals, disproportionately uses AS for stress responses. We identify core sets of genes regulated specifically by either AS or transcription upon stresses or among tissues, a regulatory specialization that is tightly mirrored by the genomic features of these genes. Unexpectedly, non-intron retention events, including exon skipping, are overrepresented across regulated AS sets in A. thaliana, being also largely involved in modulating gene expression through NMD and uORF inclusion. Conclusions Non-intron retention events have likely been functionally underrated in plants. AS constitutes a distinct regulatory layer controlling gene expression upon internal and external stimuli whose target genes and master regulators are hardwired at the genomic level to specifically undergo post-transcriptional regulation. Given the higher relevance of AS in the response to different stresses when compared to animals, this molecular hardwiring is likely required for a proper environmental response in A. thaliana.

scholarly journals PER2 Circadian Oscillation Sensitizes Esophageal Cancer Cells to Chemotherapy

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 266
Author(s):  
Juan Alfonso Redondo ◽  
Romain Bibes ◽  
Alizée Vercauteren Drubbel ◽  
Benjamin Dassy ◽  
Xavier Bisteau ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Circadian Rhythm ◽  
Survival Rate ◽  
Circadian Clock ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Human Cancer ◽  
Response To Therapy ◽  
Circadian Oscillation ◽  
Resistance To Therapy

Esophageal squamous cell carcinoma (eSCC) accounts for more than 85% cases of esophageal cancer worldwide and the 5-year survival rate associated with metastatic eSCC is poor. This low survival rate is the consequence of a complex mechanism of resistance to therapy and tumor relapse. To effectively reduce the mortality rate of this disease, we need to better understand the molecular mechanisms underlying the development of resistance to therapy and translate that knowledge into novel approaches for cancer treatment. The circadian clock orchestrates several physiological processes through the establishment and synchronization of circadian rhythms. Since cancer cells need to fuel rapid proliferation and increased metabolic demands, the escape from circadian rhythm is relevant in tumorigenesis. Although clock related genes may be globally repressed in human eSCC samples, PER2 expression still oscillates in some human eSCC cell lines. However, the consequences of this circadian rhythm are still unclear. In the present study, we confirm that PER2 oscillations still occur in human cancer cells in vitro in spite of a deregulated circadian clock gene expression. Profiling of eSCC cells by RNAseq reveals that when PER2 expression is low, several transcripts related to apoptosis are upregulated. Consistently, treating eSCC cells with cisplatin when PER2 expression is low enhances DNA damage and leads to a higher apoptosis rate. Interestingly, this process is conserved in a mouse model of chemically-induced eSCC ex vivo. These results therefore suggest that response to therapy might be enhanced in esophageal cancers using chronotherapy.

scholarly journals A survey of computational methods in transcriptome-wide alternative splicing analysis

2015 ◽  
Vol 6 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Jianbo Wang ◽  
Zhenqing Ye ◽  
Tim H.-M. Huang ◽  
Huidong Shi ◽  
Victor Jin
Keyword(s):  
Alternative Splicing ◽  
Experimental Validation ◽  
Gene Diversity ◽  
Exon Skipping ◽  
Differential Splicing ◽  
Sequencing Data ◽  
Future Directions ◽  
Specific Analysis ◽  
Software Implementations ◽  
Expected Outcomes

AbstractAlternative splicing is widely recognized for its roles in regulating genes and creating gene diversity. Consequently the identification and quantification of differentially spliced transcripts is pivotal for transcriptome analysis. Here, we review the currently available computational approaches for the analysis of RNA-sequencing data with a focus on exon-skipping events of alternative splicing and discuss the novelties as well as challenges faced to perform differential splicing analyses. In accordance with operational needs we have classified the software tools, which may be instrumental for a specific analysis based on the experimental objectives and expected outcomes. In addition, we also propose a framework for future directions by pinpointing more extensive experimental validation to assess the accuracy of the software predictions and improvements that would facilitate visualizations, data processing, and downstream analyses along with their associated software implementations.

scholarly journals Alternative splicing of synaptotagmins involving transmembrane exon skipping

FEBS Letters ◽  
1999 ◽  
Vol 460 (3) ◽  
pp. 417-422 ◽  
Author(s):  
Molly Craxton ◽  
Michel Goedert
Keyword(s):  
Alternative Splicing ◽  
Exon Skipping

Abstract 344: Finding the Achilles’ heel of Muscle Giant---TALEN-mediated Gene-editing in Zebrafish Titin

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Yu-Huan Shih ◽  
Xiaolei Xu
Keyword(s):  
Alternative Splicing ◽  
Gene Editing ◽  
Muscle Development ◽  
Exon Skipping ◽  
Transcription Activator ◽  
Detailed Characterization ◽  
A Domains ◽  
Underlying Mechanisms ◽  
Sarcomere Assembly

Background: TITIN (TTN) has more than 300 exons and encodes a gigantic protein that is crucial for heart and muscle development. Mutations in TTN caused a variety of human diseases including cardiomyopathy and muscular dystrophy. Recently, dilated cardiomyopathy-associated mutations on TTN have been found more frequently in exons encoding A-band domains but less in exons encoding the N-terminal Z-disc domains, suggesting that mutations in different exons of TTN cause distinct consequences. To elucidate the underlying mechanisms, we leveraged the Transcription Activator-Like Effects Nuclease (TALEN) technology in zebrafish to introduce truncating mutations in different exons of ttn, and then study their effects on heart and somites. Results: We generated truncational mutations in different exons of zebrafish titins encoding Z-disc, N2B, Novex-3, and A domains, respectively. Because zebrafish contains two titin homologues, ttna and ttnb, we introduced mutations in both genes at the corresponding loci. While both Z-disc and A band mutations on ttna disrupted sarcomere assembly in heart and somites, Z-disc or A band mutations on ttnb only affect somites without affecting the heart. Interestingly, a Z-disc mutation on ttna resulted in milder phenotypes than an A-band mutation, while a Z-disc mutation on ttnb generated severer phenotypes than an A-band mutation. No phenotype was observed in the homozygous fish in either ttna-novex-3 or ttnb-N2B mutant fish. Conclusions: A spectrum of truncational mutations in ttna and ttnb has been generated in zebrafish using the TALEN technology. Mutations in different exons result in different phenotypes. Detailed characterization of these mutants and double mutants will be presented, which shall elicit distinct contribution of alternative splicing and exon skipping as two candidate mechanisms during pathogenesis of Titinopathies.

scholarly journals MBNL1 alternative splicing isoforms play opposing roles in cancer

2018 ◽  
Vol 1 (5) ◽  
pp. e201800157 ◽  
Author(s):  
Tommaso Tabaglio ◽  
Diana HP Low ◽  
Winnie Koon Lay Teo ◽  
Pierre Alexis Goy ◽  
Piotr Cywoniuk ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Gene Function ◽  
Dominant Negative ◽  
Individual Gene ◽  
Cancer Types ◽  
Splicing Isoforms ◽  
Isoform Switching ◽  
And Migration

The extent of and the oncogenic role played by alternative splicing (AS) in cancer are well documented. Nonetheless, only few studies have attempted to dissect individual gene function at an isoform level. Here, we focus on the AS of splicing factors during prostate cancer progression, as these factors are known to undergo extensive AS and have the potential to affect hundreds of downstream genes. We identified exon 7 (ex7) in the MBNL1 (Muscleblind-like 1) transcript as being the most differentially included exon in cancer, both in cell lines and in patients' samples. In contrast, MBNL1 overall expression was down-regulated, consistently with its described role as a tumor suppressor. This observation holds true in the majority of cancer types analyzed. We first identified components associated to the U2 splicing complex (SF3B1, SF3A1, and PHF5A) as required for efficient ex7 inclusion and we confirmed that this exon is fundamental for MBNL1 protein homodimerization. We next used splice-switching antisense oligonucleotides (AONs) or siRNAs to compare the effect of MBNL1 splicing isoform switching with knockdown. We report that whereas the absence of MBNL1 is tolerated in cancer cells, the expression of isoforms lacking ex7 (MBNL1 Δex7) induces DNA damage and inhibits cell viability and migration, acting as dominant negative proteins. Our data demonstrate the importance of studying gene function at the level of alternative spliced isoforms and support our conclusion that MBNL1 Δex7 proteins are antisurvival factors with a defined tumor suppressive role that cancer cells tend to down-regulate in favor of MBNL +ex7 isoforms.

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