Comparative genetic analysis of inflammatory bowel disease and type 1 diabetes implicates multiple loci with opposite effects
HUMAN MOLECULAR GENETICS
Authors: Wang, Kai; Baldassano, Robert; Zhang, Haitao; Qu, Hui-Qi; Imielinski, Marcin; Kugathasan, Subra; Annese, Vito; Dubinsky, Marla; Rotter, Jerome I.; Russell, Richard K.; Bradfield, Jonathan P.; Sleiman, Patrick M. A.; Glessner, Joseph T.; Walters, Thomas; Hou, Cuiping; Kim, Cecilia; Frackelton, Edward C.; Garris, Maria; Doran, James; Romano, Claudio; Catassi, Carlo; Van Limbergen, Johan; Guthery, Stephen L.; Denson, Lee; Piccoli, David; Silverberg, Mark S.; Stanley, Charles A.; Monos, Dimitri; Wilson, David C.; Griffiths, Anne; Grant, Struan F. A.; Satsangi, Jack; Polychronakos, Constantin; Hakonarson, Hakon
Abstract
Inflammatory bowel disease, including Crohn's disease (CD) and ulcerative colitis (UC), and type 1 diabetes (T1D) are autoimmune diseases that may share common susceptibility pathways. We examined known susceptibility loci for these diseases in a cohort of 1689 CD cases, 777 UC cases, 989 T1D cases and 6197 shared control subjects of European ancestry, who were genotyped by the Illumina HumanHap550 SNP arrays. We identified multiple previously unreported or unconfirmed disease associations, including known CD loci (ICOSLG and TNFSF15) and T1D loci (TNFAIP3) that confer UC risk, known UC loci (HERC2 and IL26) that confer T1D risk and known UC loci (IL10 and CCNY) that confer CD risk. Additionally, we show that T1D risk alleles residing at the PTPN22, IL27, IL18RAP and IL10 loci protect against CD. Furthermore, the strongest risk alleles for T1D within the major histocompatibility complex (MHC) confer strong protection against CD and UC; however, given the multi-allelic nature of the MHC haplotypes, sequencing of the MHC locus will be required to interpret this observation. These results extend our current knowledge on genetic variants that predispose to autoimmunity, and suggest that many loci involved in autoimmunity may be under a balancing selection due to antagonistic pleiotropic effect. Our analysis implies that variants with opposite effects on different diseases may facilitate the maintenance of common susceptibility alleles in human populations, making autoimmune diseases especially amenable to genetic dissection by genome-wide association studies.
A pathway-based approach for identifying biomarkers of tumor progression to trastuzumab-resistant breast cancer
CANCER LETTERS
Authors: Nam, Seungyoon; Chang, Hae Ryung; Jung, Hae Rim; Gim, Youme; Kim, Nam Youl; Grailhe, Regis; Seo, Haeng Ran; Park, Hee Seo; Balch, Curt; Lee, Jinhyuk; Park, Inhae; Jung, So Youn; Jeong, Kyung-Chae; Powis, Garth; Liang, Han; Lee, Eun Sook; Ro, Jungsil; Kim, Yon Hui
Abstract
Although trastuzumab is a successful targeted therapy for breast cancer patients with tumors expressing HER2 (ERBB2), many patients eventually progress to drug resistance. Here, we identified subpathways differentially expressed between trastuzumab-resistant vs. -sensitive breast cancer cells, in conjunction with additional transcriptomic preclinical and clinical gene datasets, to rigorously identify overexpressed, resistance-associated genes. From this approach, we identified 32 genes reproducibly upregulated in trastuzumab resistance. 25 genes were upregulated in drug-resistant JIMT-1 cells, which also downregulated HER2 protein by >80% in the presence of trastuzumab. 24 genes were downregulated in trastuzumab-sensitive SKBR3 cells. Trastuzumab sensitivity was restored by siRNA knockdown of these genes in the resistant cells, and overexpression of 5 of the 25 genes was found in at least one of five refractory HER2 + breast cancer. In summary, our rigorous computational approach, followed by experimental validation, significantly implicate ATF4, CHEK2, ENAH, ICOSLG, and RAD51 as potential biomarkers of trastuzumab resistance. These results provide further proof-of-concept of our methodology for successfully identifying potential biomarkers and druggable signal pathways involved in tumor progression to drug resistance. (C) 2014 The Authors. Published by Elsevier Ireland Ltd. This is an open access article under the CC BYNC-SA license (http://creativecommons.org/licenses/by-nc-sa/3.0/).