Kansler, Email: ude.gniretteknaols@erelsnak. Akanksha Verma, Email: ude.llenroc.dem@1003vka. Erin M. progression and drug resistance for cross-species genomic analysis in melanoma. Zebrafish transgenic tumors are initiated with just 2 genetic lesions, BRAFV600E and p53-/-, yet take 4C6 months to appear, at which time whole genome sequencing demonstrated 3,000 new mutations. An additional 4-month exposure to the BRAF inhibitor vemurafenib resulted in a highly drug resistant tumor that showed 3 additional new DNA mutations in the genes BUB1B, PINK1, and COL16A1. These genetic changes in drug resistance are accompanied by a massive reorganization of the transcriptome, with differential RNA expression of over 800 genes, centered on alterations in cAMP and PKA signaling. By comparing both the DNA and mRNA changes to a large panel of human melanomas, we find that there is a highly significant enrichment of these alterations in human patients with vemurafenib resistant disease. Conclusions Our results suggest that targeting of alterations that are conserved between zebrafish and humans may offer new avenues for therapeutic intervention. The approaches described here will be broadly applicable to the diverse array H-1152 dihydrochloride of cancer models available in the zebrafish, which can be used to inform human cancer genomics. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3518-8) contains supplementary material, which is available to authorized users. strong class=”kwd-title” Keywords: Cancer, Zebrafish, Drug-resistance, Melanoma Background Large-scale advances in genomic profiling of human cancers has enabled the identification of thousands of new potential genetic and epigenetic targets [1]. In melanoma, this effort has been complicated by the relatively high background mutation rate induced by ultraviolet light (UV) [2]. This is further complicated by recent observations that even seemingly normal skin harbors large mutational burdens due to UV, [3], making it difficult to discern which events are truly pathogenic versus those that occur simply as bystanders. Along with ultraviolet light, human melanomas also exhibit tremendous inter-patient heterogeneity. This is likely due to several factors: 1) a variety of genes can act as initiating events (i.e. BRAF, NRAS, c-Kit), 2) a lack of knowledge of the cell of origin of individual tumors, and 3) individual germline variation in DNA repair mechanisms. As the tumors evolve under drug therapy (i.e. BRAF inhibitors or immunotherapy), each of these factors make it increasingly challenging to identify key genomic events promoting such evolution. Evaluating genetic evolution in melanoma will be facilitated by Rabbit Polyclonal to Transglutaminase 2 models which faithfully recapitulate the human disease, yet allow for precise control over the above variables. This will allow for identification of core mutational events and mechanisms that are intrinsic to melanoma, and not simply due to the background effects of UV radiation. Towards this end, we and others have previously H-1152 dihydrochloride developed several zebrafish models of melanoma [4C7] H-1152 dihydrochloride that show remarkable similarity to the human disease at histological, functional and genomic levels [8]. The zebrafish has emerged as an important new model in cancer biology because of its unique capabilities in terms of transgenesis, genetic manipulation, unbiased screens and in vivo imaging [9]. The advantages of evaluating cancer evolution in models such as the fish is that we can rigorously control the cell of tumor initiation, use genetically well-defined oncogenic initiating events and the fish spontaneously develop melanoma in a well-defined germline background. One limitation of using these transgenic models of malignancy is a lack of computational H-1152 dihydrochloride methods for assessing the tumor genomes over time and space. We previously utilized an exome-sequencing approach to determine genes under selection in these melanomas [8], but did not address mutation rates genome-wide or how this changes during the emergence of drug resistance. Such an approach will become necessary to truly capitalize within the advantages of the zebrafish malignancy models. Here, we utilize a transgenic zebrafish melanoma to define genetic events that happen in the weeks after the initiation of BRAFV600E manifestation, and determine H-1152 dihydrochloride how these tumors develop under drug selection having a BRAF inhibitor, as schematically shown in Fig.?1. These data reveal a amazing amount of genetic evolution that occurs in the absence of UV damage, which can be further augmented after these melanomas become resistant to BRAF inhibitors. These data suggest that the mechanisms leading to genomic instability in melanoma may not solely be due to a straightforward mutagenic insult such as UV, and likely reflects properties of the melanoma cell itself. Open in a separate windowpane Fig. 1 Schematic representation of experimental strategy. Fish with the genotype mitfa-BRAFV600E+/+;p53-/-;mitfa-/- are completely devoid of melanocytes due to.
