Please use this identifier to cite or link to this item: http://ahro.austin.org.au/austinjspui/handle/1/11179
Title: Nonsense mediated decay resistant mutations are a source of expressed mutant proteins in colon cancer cell lines with microsatellite instability.
Authors: Williams, David S;Bird, Matthew J;Jorissen, Robert N;Yu, Yen Lin;Walker, Franscesa;Zhang, Hui Hua;Nice, Edouard C;Burgess, Antony W
Affiliation: Epithelial Biochemistry Laboratory, Ludwig Institute for Cancer Research, Melbourne Branch, Parkville, Victoria, Australia. David.Williams@austin.org.au
Issue Date: 31-Dec-2010
Citation: Plos One 2010; 5(12): e16012
Abstract: Frameshift mutations in microsatellite instability high (MSI-High) colorectal cancers are a potential source of targetable neo-antigens. Many nonsense transcripts are subject to rapid degradation due to nonsense-mediated decay (NMD), but nonsense transcripts with a cMS in the last exon or near the last exon-exon junction have intrinsic resistance to nonsense-mediated decay (NMD). NMD-resistant transcripts are therefore a likely source of expressed mutant proteins in MSI-High tumours.Using antibodies to the conserved N-termini of predicted mutant proteins, we analysed MSI-High colorectal cancer cell lines for examples of naturally expressed mutant proteins arising from frameshift mutations in coding microsatellites (cMS) by immunoprecipitation and Western Blot experiments. Detected mutant protein bands from NMD-resistant transcripts were further validated by gene-specific short-interfering RNA (siRNA) knockdown. A genome-wide search was performed to identify cMS-containing genes likely to generate NMD-resistant transcripts that could encode for antigenic expressed mutant proteins in MSI-High colon cancers. These genes were screened for cMS mutations in the MSI-High colon cancer cell lines.Mutant protein bands of expected molecular weight were detected in mutated MSI-High cell lines for NMD-resistant transcripts (CREBBP, EP300, TTK), but not NMD-sensitive transcripts (BAX, CASP5, MSH3). Expression of the mutant CREBBP and EP300 proteins was confirmed by siRNA knockdown. Five cMS-bearing genes identified from the genome-wide search and without existing mutation data (SFRS12IP1, MED8, ASXL1, FBXL3 and RGS12) were found to be mutated in at least 5 of 11 (45%) of the MSI-High cell lines tested.NMD-resistant transcripts can give rise to expressed mutant proteins in MSI-High colon cancer cells. If commonly expressed in primary MSI-High colon cancers, MSI-derived mutant proteins could be useful as cancer specific immunological targets in a vaccine targeting MSI-High colonic tumours.
Internal ID Number: 21209843
URI: http://ahro.austin.org.au/austinjspui/handle/1/11179
DOI: 10.1371/journal.pone.0016012
URL: http://www.ncbi.nlm.nih.gov/pubmed/21209843
Type: Journal Article
Subjects: Cell Line, Tumor
Codon, Nonsense
Colonic Neoplasms.genetics
Computational Biology.methods
DNA Repair
Epitope Mapping
Frameshift Mutation
Gene Expression Regulation, Neoplastic
Genome
HLA-A Antigens.genetics
Humans
Microsatellite Instability
Microsatellite Repeats
Mutation
Protein Structure, Tertiary
Appears in Collections:Journal articles

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