Project description:Pancreatic cancer is among the deadliest cancers that affects almost 54,000 patients in United States alone, with 90% of them succumbing to the disease. Lack of early detection is considered to be the foremost reason for such dismal survival rates. Our study shows that resident gut microbiota is altered at the early stages of tumorigenesis much before development of observable tumors in a spontaneous, genetically engineered mouse model for pancreatic cancer. In the current study, we analyzed the microbiome of in a genetic mouse model for PDAC (KRASG12DTP53R172HPdxCre or KPC) and age-matched controls using WGS at very early time points of tumorigenesis. During these time points, the KPC mice do not show any detectable tumors in their pancreas. Our results show that at these early time points, the histological changes in the pancreas correspond to a significant change in certain gut microbial population. Our predictive metabolomic analysis on the identified bacterial species reveal that the primary microbial metabolites involved in progression and development of PDAC tumors are involved in polyamine metabolism.
Project description:We harvested and sequenced the spontaneous pancreatic tumor generated by a 6-month-old KPC mouse (KrasLSL-G12D; Trp53LSL-R172H; Ptf1a-Cre).
2022-10-04 | GSE202651 | GEO
Project description:KPC variants in Pseudomonas aeruginosa
Project description:We have conducted a genome-wide analysis of spontaneous copy number variation (CNV) in the laboratory mouse. We used high resolution microarrays to identify 38 CNVs between 14 colonies of the C57BL/6 strain spanning ~967 generations of inbreeding, and examined these loci in 12 additional strains. It is clear from our results that many CNVs arise through a highly non-random process: 18 of 38 were the product of recurrent mutation, and rates of change vary roughly four orders of magnitude across different loci. These recurrent CNVs are distributed throughout the genome, affect 43 genes, and fluctuate in copy number over mere hundreds of generations, observations that raise questions about their contribution to natural variation. Keywords: Representational oligonucleotide microarray analysis, comparative genomic hybridization, DNA copy number variation, structural variation, inbred mice, spontaneous mutation rate
Project description:We have conducted a genome-wide analysis of spontaneous copy number variation (CNV) in the laboratory mouse. We used high resolution microarrays to identify 38 CNVs between 14 colonies of the C57BL/6 strain spanning ~967 generations of inbreeding, and examined these loci in 12 additional strains. It is clear from our results that many CNVs arise through a highly non-random process: 18 of 38 were the product of recurrent mutation, and rates of change vary roughly four orders of magnitude across different loci. These recurrent CNVs are distributed throughout the genome, affect 43 genes, and fluctuate in copy number over mere hundreds of generations, observations that raise questions about their contribution to natural variation. Keywords: comparative genomic hybridization, DNA copy number variation, structural variation, inbred mice, spontaneous mutation rate
Project description:To investigate the transcriptomic effects of iASPP deletion or p53 mutation in the KRASG12D background Pdx1-Cre was used to delete iASPP in oncogenic KRASG12D expressing (KC) background to generate KC;iASPPΔ8/Δ8 mice. KC and KC;iASPPΔ8/Δ8 mice were then crossed with mice containing a p53R172H allele (equivalent to human p53 hotspot mutation R175H) to generate KPC and KPC;iASPPΔ8/Δ8 cohorts. Primary cell cultures were then derived from pancreatic ductal adenocarcinoma tissue for RNA-seq.
Project description:Gene copy-number variation, which provides the raw material for the evolution of novel genes, is surprisingly widespread in natural populations. Experimental evolution studies have demonstrated an extremely high spontaneous rate of origin of gene duplications. When organisms are suboptimally adapted to their environment, gene duplication may compensate for reduced fitness by amplifying promiscuous activity of a gene, or increasing dosage of a suboptimal gene. The overarching goal of this study is to inverstigate whether CNVs constitute a common mechanism of adaptive genetic change during compensatory evolution and to further characterize the role of natural selection in dictating their evolutionary spread at a population-genomic level. Outcrossing populations of C. elegans with low fitness were evolved for >200 generations and the frequencies of CNVs in these populations were analyzed by oligonucleotide array comparative genome hybridization, quantitative PCR, and single-worm PCR. Multiple duplications and deletions were detected in intermediate to high frequencies and several lines of evidence suggest that the changes in frequency were adaptive. 1) Many copy-number changes reached high frequency, were near fixation, or were fixed in a short time. 2) Many independent duplications and deletions in high frequency harbor overlapping regions which likely include genes that are under selection for either higher or lower rates of expression. 3) The size spectrum of deuplications and deletions in the adaptive recovery populations is significantly larger than that of spontaneous copy-number variants in mutation accumulation experiments. This is expected if larger CNVs are more likely to encompass genes that are being selected for altered gene dosage. Out results validate the great potential borne by gene copy-number changes for compensatory evolution and adaptation. Experimental genome evolution of copy-number variants in 25 experimental lines compared to 5 ancestral control lines.