Integration of genomics, metagenomics, and metabolomics to identify interplay between susceptibility alleles and microbiota in adenoma initiation
BMC CANCER
Authors: Moskowitz, Jacob E.; Doran, Anthony G.; Lei, Zhentian; Busi, Susheel B.; Hart, Marcia L.; Franklin, Craig L.; Sumner, Lloyd W.; Keane, Thomas M.; Amos-Landgraf, James M.
Abstract
BackgroundColorectal cancer (CRC) is a multifactorial disease resulting from both genetic predisposition and environmental factors including the gut microbiota (GM), but deciphering the influence of genetic variants, environmental variables, and interactions with the GM is exceedingly difficult. We previously observed significant differences in intestinal adenoma multiplicity between C57BL/6J-Apc(Min) (B6-Min/J) from The Jackson Laboratory (JAX), and original founder strain C57BL/6JD-Apc(Min) (B6-Min/D) from the University of Wisconsin.MethodsTo resolve genetic and environmental interactions and determine their contributions we utilized two genetically inbred, independently isolated Apc(Min) mouse colonies that have been separated for over 20 generations. Whole genome sequencing was used to identify genetic variants unique to the two substrains. To determine the influence of genetic variants and the impact of differences in the GM on phenotypic variability, we used complex microbiota targeted rederivation to generate two Apc mutant mouse colonies harboring complex GMs from two different sources (GMJAX originally from JAX or GMHSD originally from Envigo), creating four Apc(Min) groups. Untargeted metabolomics were used to characterize shifts in the fecal metabolite profile based on genetic variation and differences in the GM.ResultsWGS revealed several thousand high quality variants unique to the two substrains. No homozygous variants were present in coding regions, with the vast majority of variants residing in noncoding regions. Host genetic divergence between Min/J and Min/D and the complex GM additively determined differential adenoma susceptibility. Untargeted metabolomics revealed that both genetic lineage and the GM collectively determined the fecal metabolite profile, and that each differentially regulates bile acid (BA) metabolism. Metabolomics pathway analysis facilitated identification of a functionally relevant private noncoding variant associated with the bile acid transporter Fatty acid binding protein 6 (Fabp6). Expression studies demonstrated differential expression of Fabp6 between Min/J and Min/D, and the variant correlates with adenoma multiplicity in backcrossed mice.ConclusionsWe found that both genetic variation and differences in microbiota influences the quantitiative adenoma phenotype in Apc(Min) mice. These findings demonstrate how the use of metabolomics datasets can aid as a functional genomic tool, and furthermore illustrate the power of a multi-omics approach to dissect complex disease susceptibility of noncoding variants.
Fatty acid binding protein 7 may be a marker and therapeutic targets in clear cell renal cell carcinoma
BMC CANCER
Authors: Nagao, Kazuhiro; Shinohara, Nachi; Smit, Frank; de Weijert, Mirjam; Jannink, Sander; Owada, Yuji; Mulders, Peter; Oosterwijk, Egbert; Matsuyama, Hideyasu
Abstract
Background: To identify potential therapeutic target in clear cell renal cell carcinoma (ccRCC), we performed a transcriptome analysis. Our analysis showed that fatty acid binding protein 7 (FABP7) has the highest mean differential overexpression in ccRCC compared to normal kidney. We aimed to investigate the significance of FABP7 in ccRCC. Methods: Immunohistochemical staining for 40 advanced ccRCC cases was performed to investigate correlation between clinicopathological parameters and FABP7. They were composed of 40-83 years old cases with 33 male, 22 cases with pT = 3, 19 cases with M1, and 16 cases with grade 3. The effect of gene knockdown was analysed by a cell viability assay and invasion assay in FABP7-overexpressing cell lines (SKRC7 and SKRC10). Results: Our immunohistochemical analysis showed that higher FABP7 expression significantly correlated with distant metastasis and poor cancer-specific survival (CSS; both p < 0.05). Functional suppression of FABP7 significantly inhibited SKRC10 cell growth (p < 0.05) and resulted in a significant reduction of the invasive potential (p < 0.01), but did not cause growth inhibition of SKRC7 cells. We found that The Cancer Genome Atlas Research Network (TCGA) database shows FABP6 and 7 as equally overexpressed in the FABP family. Functional suppression of fatty acid binding protein 6 (FABP6) resulted in significant growth inhibition of SKRC7 cells (p < 0.005). Conclusions: Functional suppression of FABP7 significantly reduced cell viability and invasive potential in a ccRCC cell line. FABP7 may play a role in progression in some metastatic ccRCCs. The suppressed function may be compensated by another FABP family member.