%0 Journal Article %J Nat Genet %D 2021 %T The trans-ancestral genomic architecture of glycemic traits. %A Chen, Ji %A Spracklen, Cassandra N %A Marenne, Gaëlle %A Varshney, Arushi %A Corbin, Laura J %A Luan, Jian'an %A Willems, Sara M %A Wu, Ying %A Zhang, Xiaoshuai %A Horikoshi, Momoko %A Boutin, Thibaud S %A Mägi, Reedik %A Waage, Johannes %A Li-Gao, Ruifang %A Chan, Kei Hang Katie %A Yao, Jie %A Anasanti, Mila D %A Chu, Audrey Y %A Claringbould, Annique %A Heikkinen, Jani %A Hong, Jaeyoung %A Hottenga, Jouke-Jan %A Huo, Shaofeng %A Kaakinen, Marika A %A Louie, Tin %A Marz, Winfried %A Moreno-Macias, Hortensia %A Ndungu, Anne %A Nelson, Sarah C %A Nolte, Ilja M %A North, Kari E %A Raulerson, Chelsea K %A Ray, Debashree %A Rohde, Rebecca %A Rybin, Denis %A Schurmann, Claudia %A Sim, Xueling %A Southam, Lorraine %A Stewart, Isobel D %A Wang, Carol A %A Wang, Yujie %A Wu, Peitao %A Zhang, Weihua %A Ahluwalia, Tarunveer S %A Appel, Emil V R %A Bielak, Lawrence F %A Brody, Jennifer A %A Burtt, Noël P %A Cabrera, Claudia P %A Cade, Brian E %A Chai, Jin Fang %A Chai, Xiaoran %A Chang, Li-Ching %A Chen, Chien-Hsiun %A Chen, Brian H %A Chitrala, Kumaraswamy Naidu %A Chiu, Yen-Feng %A de Haan, Hugoline G %A Delgado, Graciela E %A Demirkan, Ayse %A Duan, Qing %A Engmann, Jorgen %A Fatumo, Segun A %A Gayán, Javier %A Giulianini, Franco %A Gong, Jung Ho %A Gustafsson, Stefan %A Hai, Yang %A Hartwig, Fernando P %A He, Jing %A Heianza, Yoriko %A Huang, Tao %A Huerta-Chagoya, Alicia %A Hwang, Mi Yeong %A Jensen, Richard A %A Kawaguchi, Takahisa %A Kentistou, Katherine A %A Kim, Young Jin %A Kleber, Marcus E %A Kooner, Ishminder K %A Lai, Shuiqing %A Lange, Leslie A %A Langefeld, Carl D %A Lauzon, Marie %A Li, Man %A Ligthart, Symen %A Liu, Jun %A Loh, Marie %A Long, Jirong %A Lyssenko, Valeriya %A Mangino, Massimo %A Marzi, Carola %A Montasser, May E %A Nag, Abhishek %A Nakatochi, Masahiro %A Noce, Damia %A Noordam, Raymond %A Pistis, Giorgio %A Preuss, Michael %A Raffield, Laura %A Rasmussen-Torvik, Laura J %A Rich, Stephen S %A Robertson, Neil R %A Rueedi, Rico %A Ryan, Kathleen %A Sanna, Serena %A Saxena, Richa %A Schraut, Katharina E %A Sennblad, Bengt %A Setoh, Kazuya %A Smith, Albert V %A Sparsø, Thomas %A Strawbridge, Rona J %A Takeuchi, Fumihiko %A Tan, Jingyi %A Trompet, Stella %A van den Akker, Erik %A van der Most, Peter J %A Verweij, Niek %A Vogel, Mandy %A Wang, Heming %A Wang, Chaolong %A Wang, Nan %A Warren, Helen R %A Wen, Wanqing %A Wilsgaard, Tom %A Wong, Andrew %A Wood, Andrew R %A Xie, Tian %A Zafarmand, Mohammad Hadi %A Zhao, Jing-Hua %A Zhao, Wei %A Amin, Najaf %A Arzumanyan, Zorayr %A Astrup, Arne %A Bakker, Stephan J L %A Baldassarre, Damiano %A Beekman, Marian %A Bergman, Richard N %A Bertoni, Alain %A Blüher, Matthias %A Bonnycastle, Lori L %A Bornstein, Stefan R %A Bowden, Donald W %A Cai, Qiuyin %A Campbell, Archie %A Campbell, Harry %A Chang, Yi Cheng %A de Geus, Eco J C %A Dehghan, Abbas %A Du, Shufa %A Eiriksdottir, Gudny %A Farmaki, Aliki Eleni %A Frånberg, Mattias %A Fuchsberger, Christian %A Gao, Yutang %A Gjesing, Anette P %A Goel, Anuj %A Han, Sohee %A Hartman, Catharina A %A Herder, Christian %A Hicks, Andrew A %A Hsieh, Chang-Hsun %A Hsueh, Willa A %A Ichihara, Sahoko %A Igase, Michiya %A Ikram, M Arfan %A Johnson, W Craig %A Jørgensen, Marit E %A Joshi, Peter K %A Kalyani, Rita R %A Kandeel, Fouad R %A Katsuya, Tomohiro %A Khor, Chiea Chuen %A Kiess, Wieland %A Kolcic, Ivana %A Kuulasmaa, Teemu %A Kuusisto, Johanna %A Läll, Kristi %A Lam, Kelvin %A Lawlor, Deborah A %A Lee, Nanette R %A Lemaitre, Rozenn N %A Li, Honglan %A Lin, Shih-Yi %A Lindström, Jaana %A Linneberg, Allan %A Liu, Jianjun %A Lorenzo, Carlos %A Matsubara, Tatsuaki %A Matsuda, Fumihiko %A Mingrone, Geltrude %A Mooijaart, Simon %A Moon, Sanghoon %A Nabika, Toru %A Nadkarni, Girish N %A Nadler, Jerry L %A Nelis, Mari %A Neville, Matt J %A Norris, Jill M %A Ohyagi, Yasumasa %A Peters, Annette %A Peyser, Patricia A %A Polasek, Ozren %A Qi, Qibin %A Raven, Dennis %A Reilly, Dermot F %A Reiner, Alex %A Rivideneira, Fernando %A Roll, Kathryn %A Rudan, Igor %A Sabanayagam, Charumathi %A Sandow, Kevin %A Sattar, Naveed %A Schürmann, Annette %A Shi, Jinxiu %A Stringham, Heather M %A Taylor, Kent D %A Teslovich, Tanya M %A Thuesen, Betina %A Timmers, Paul R H J %A Tremoli, Elena %A Tsai, Michael Y %A Uitterlinden, Andre %A van Dam, Rob M %A van Heemst, Diana %A van Hylckama Vlieg, Astrid %A Van Vliet-Ostaptchouk, Jana V %A Vangipurapu, Jagadish %A Vestergaard, Henrik %A Wang, Tao %A Willems van Dijk, Ko %A Zemunik, Tatijana %A Abecasis, Gonçalo R %A Adair, Linda S %A Aguilar-Salinas, Carlos Alberto %A Alarcón-Riquelme, Marta E %A An, Ping %A Aviles-Santa, Larissa %A Becker, Diane M %A Beilin, Lawrence J %A Bergmann, Sven %A Bisgaard, Hans %A Black, Corri %A Boehnke, Michael %A Eric Boerwinkle %A Böhm, Bernhard O %A Bønnelykke, Klaus %A Boomsma, D I %A Bottinger, Erwin P %A Buchanan, Thomas A %A Canouil, Mickaël %A Caulfield, Mark J %A Chambers, John C %A Chasman, Daniel I %A Chen, Yii-Der Ida %A Cheng, Ching-Yu %A Collins, Francis S %A Correa, Adolfo %A Cucca, Francesco %A de Silva, H Janaka %A Dedoussis, George %A Elmståhl, Sölve %A Evans, Michele K %A Ferrannini, Ele %A Ferrucci, Luigi %A Florez, Jose C %A Franks, Paul W %A Frayling, Timothy M %A Froguel, Philippe %A Gigante, Bruna %A Goodarzi, Mark O %A Gordon-Larsen, Penny %A Grallert, Harald %A Grarup, Niels %A Grimsgaard, Sameline %A Groop, Leif %A Gudnason, Vilmundur %A Guo, Xiuqing %A Hamsten, Anders %A Hansen, Torben %A Hayward, Caroline %A Heckbert, Susan R %A Horta, Bernardo L %A Huang, Wei %A Ingelsson, Erik %A James, Pankow S %A Jarvelin, Marjo-Ritta %A Jonas, Jost B %A Jukema, J Wouter %A Kaleebu, Pontiano %A Kaplan, Robert %A Kardia, Sharon L R %A Kato, Norihiro %A Keinanen-Kiukaanniemi, Sirkka M %A Kim, Bong-Jo %A Kivimaki, Mika %A Koistinen, Heikki A %A Kooner, Jaspal S %A Körner, Antje %A Kovacs, Peter %A Kuh, Diana %A Kumari, Meena %A Kutalik, Zoltán %A Laakso, Markku %A Lakka, Timo A %A Launer, Lenore J %A Leander, Karin %A Li, Huaixing %A Lin, Xu %A Lind, Lars %A Lindgren, Cecilia %A Liu, Simin %A Loos, Ruth J F %A Magnusson, Patrik K E %A Mahajan, Anubha %A Metspalu, Andres %A Mook-Kanamori, Dennis O %A Mori, Trevor A %A Munroe, Patricia B %A Njølstad, Inger %A O'Connell, Jeffrey R %A Oldehinkel, Albertine J %A Ong, Ken K %A Padmanabhan, Sandosh %A Palmer, Colin N A %A Palmer, Nicholette D %A Pedersen, Oluf %A Pennell, Craig E %A Porteous, David J %A Pramstaller, Peter P %A Province, Michael A %A Psaty, Bruce M %A Qi, Lu %A Raffel, Leslie J %A Rauramaa, Rainer %A Redline, Susan %A Ridker, Paul M %A Rosendaal, Frits R %A Saaristo, Timo E %A Sandhu, Manjinder %A Saramies, Jouko %A Schneiderman, Neil %A Schwarz, Peter %A Scott, Laura J %A Selvin, Elizabeth %A Sever, Peter %A Shu, Xiao-Ou %A Slagboom, P Eline %A Small, Kerrin S %A Smith, Blair H %A Snieder, Harold %A Sofer, Tamar %A Sørensen, Thorkild I A %A Spector, Tim D %A Stanton, Alice %A Steves, Claire J %A Stumvoll, Michael %A Sun, Liang %A Tabara, Yasuharu %A Tai, E Shyong %A Timpson, Nicholas J %A Tonjes, Anke %A Tuomilehto, Jaakko %A Tusie, Teresa %A Uusitupa, Matti %A van der Harst, Pim %A van Duijn, Cornelia %A Vitart, Veronique %A Vollenweider, Peter %A Vrijkotte, Tanja G M %A Wagenknecht, Lynne E %A Walker, Mark %A Wang, Ya X %A Wareham, Nick J %A Watanabe, Richard M %A Watkins, Hugh %A Wei, Wen B %A Wickremasinghe, Ananda R %A Willemsen, Gonneke %A Wilson, James F %A Wong, Tien-Yin %A Wu, Jer-Yuarn %A Xiang, Anny H %A Yanek, Lisa R %A Yengo, Loic %A Yokota, Mitsuhiro %A Zeggini, Eleftheria %A Zheng, Wei %A Zonderman, Alan B %A Rotter, Jerome I %A Gloyn, Anna L %A McCarthy, Mark I %A Dupuis, Josée %A Meigs, James B %A Scott, Robert A %A Prokopenko, Inga %A Leong, Aaron %A Liu, Ching-Ti %A Parker, Stephen C J %A Mohlke, Karen L %A Langenberg, Claudia %A Wheeler, Eleanor %A Morris, Andrew P %A Barroso, Inês %K Alleles %K Blood Glucose %K Epigenesis, Genetic %K Gene Expression Profiling %K Genome, Human %K Genome-Wide Association Study %K Glycated Hemoglobin %K Humans %K Multifactorial Inheritance %K Physical Chromosome Mapping %K Quantitative Trait Loci %K Quantitative Trait, Heritable %K White People %X

Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 × 10), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.

%B Nat Genet %V 53 %P 840-860 %8 2021 Jun %G eng %N 6 %1 https://www.ncbi.nlm.nih.gov/pubmed/34059833?dopt=Abstract %R 10.1038/s41588-021-00852-9 %0 Journal Article %J PLoS Genet %D 2019 %T Use of >100,000 NHLBI Trans-Omics for Precision Medicine (TOPMed) Consortium whole genome sequences improves imputation quality and detection of rare variant associations in admixed African and Hispanic/Latino populations. %A Kowalski, Madeline H %A Qian, Huijun %A Hou, Ziyi %A Rosen, Jonathan D %A Tapia, Amanda L %A Shan, Yue %A Jain, Deepti %A Argos, Maria %A Arnett, Donna K %A Avery, Christy %A Barnes, Kathleen C %A Becker, Lewis C %A Bien, Stephanie A %A Bis, Joshua C %A Blangero, John %A Eric Boerwinkle %A Bowden, Donald W %A Buyske, Steve %A Cai, Jianwen %A Cho, Michael H %A Choi, Seung Hoan %A Choquet, Hélène %A Cupples, L Adrienne %A Cushman, Mary %A Daya, Michelle %A de Vries, Paul S %A Ellinor, Patrick T %A Faraday, Nauder %A Fornage, Myriam %A Gabriel, Stacey %A Ganesh, Santhi K %A Graff, Misa %A Gupta, Namrata %A He, Jiang %A Heckbert, Susan R %A Hidalgo, Bertha %A Hodonsky, Chani J %A Irvin, Marguerite R %A Johnson, Andrew D %A Jorgenson, Eric %A Kaplan, Robert %A Kardia, Sharon L R %A Kelly, Tanika N %A Kooperberg, Charles %A Lasky-Su, Jessica A %A Loos, Ruth J F %A Lubitz, Steven A %A Mathias, Rasika A %A McHugh, Caitlin P %A Montgomery, Courtney %A Moon, Jee-Young %A Morrison, Alanna C %A Palmer, Nicholette D %A Pankratz, Nathan %A Papanicolaou, George J %A Peralta, Juan M %A Peyser, Patricia A %A Rich, Stephen S %A Rotter, Jerome I %A Silverman, Edwin K %A Smith, Jennifer A %A Smith, Nicholas L %A Taylor, Kent D %A Thornton, Timothy A %A Tiwari, Hemant K %A Tracy, Russell P %A Wang, Tao %A Weiss, Scott T %A Weng, Lu-Chen %A Wiggins, Kerri L %A Wilson, James G %A Yanek, Lisa R %A Zöllner, Sebastian %A North, Kari E %A Auer, Paul L %A Raffield, Laura M %A Reiner, Alexander P %A Li, Yun %K Adult %K Aged %K Aged, 80 and over %K beta-Globins %K Black or African American %K Computational Biology %K Databases, Genetic %K Female %K Gene Frequency %K Genetic Predisposition to Disease %K Genetics, Population %K Genome-Wide Association Study %K Genotyping Techniques %K Hispanic or Latino %K Humans %K Linkage Disequilibrium %K Male %K Middle Aged %K Precision Medicine %K United States %K Whole Genome Sequencing %X

Most genome-wide association and fine-mapping studies to date have been conducted in individuals of European descent, and genetic studies of populations of Hispanic/Latino and African ancestry are limited. In addition, these populations have more complex linkage disequilibrium structure. In order to better define the genetic architecture of these understudied populations, we leveraged >100,000 phased sequences available from deep-coverage whole genome sequencing through the multi-ethnic NHLBI Trans-Omics for Precision Medicine (TOPMed) program to impute genotypes into admixed African and Hispanic/Latino samples with genome-wide genotyping array data. We demonstrated that using TOPMed sequencing data as the imputation reference panel improves genotype imputation quality in these populations, which subsequently enhanced gene-mapping power for complex traits. For rare variants with minor allele frequency (MAF) < 0.5%, we observed a 2.3- to 6.1-fold increase in the number of well-imputed variants, with 11-34% improvement in average imputation quality, compared to the state-of-the-art 1000 Genomes Project Phase 3 and Haplotype Reference Consortium reference panels. Impressively, even for extremely rare variants with minor allele count <10 (including singletons) in the imputation target samples, average information content rescued was >86%. Subsequent association analyses of TOPMed reference panel-imputed genotype data with hematological traits (hemoglobin (HGB), hematocrit (HCT), and white blood cell count (WBC)) in ~21,600 African-ancestry and ~21,700 Hispanic/Latino individuals identified associations with two rare variants in the HBB gene (rs33930165 with higher WBC [p = 8.8x10-15] in African populations, rs11549407 with lower HGB [p = 1.5x10-12] and HCT [p = 8.8x10-10] in Hispanics/Latinos). By comparison, neither variant would have been genome-wide significant if either 1000 Genomes Project Phase 3 or Haplotype Reference Consortium reference panels had been used for imputation. Our findings highlight the utility of the TOPMed imputation reference panel for identification of novel rare variant associations not previously detected in similarly sized genome-wide studies of under-represented African and Hispanic/Latino populations.

%B PLoS Genet %V 15 %P e1008500 %8 2019 Dec %G eng %N 12 %1 https://www.ncbi.nlm.nih.gov/pubmed/31869403?dopt=Abstract %R 10.1371/journal.pgen.1008500 %0 Journal Article %J JAMA Oncol %D 2016 %T Diagnostic Yield of Clinical Tumor and Germline Whole-Exome Sequencing for Children With Solid Tumors. %A Parsons, D Williams %A Roy, Angshumoy %A Yang, Yaping %A Wang, Tao %A Scollon, Sarah %A Bergstrom, Katie %A Kerstein, Robin A %A Gutierrez, Stephanie %A Petersen, Andrea K %A Bavle, Abhishek %A Lin, Frank Y %A López-Terrada, Dolores H %A Monzon, Federico A %A Hicks, M John %A Eldin, Karen W %A Quintanilla, Norma M %A Adesina, Adekunle M %A Mohila, Carrie A %A Whitehead, William %A Jea, Andrew %A Vasudevan, Sanjeev A %A Nuchtern, Jed G %A Ramamurthy, Uma %A McGuire, Amy L %A Hilsenbeck, Susan G %A Reid, Jeffrey G %A Donna M Muzny %A Wheeler, David A %A Berg, Stacey L %A Chintagumpala, Murali M %A Eng, Christine M %A Richard A Gibbs %A Plon, Sharon E %X

IMPORTANCE: Whole-exome sequencing (WES) has the potential to reveal tumor and germline mutations of clinical relevance, but the diagnostic yield for pediatric patients with solid tumors is unknown.

OBJECTIVE: To characterize the diagnostic yield of combined tumor and germline WES for children with solid tumors.

DESIGN: Unselected children with newly diagnosed and previously untreated central nervous system (CNS) and non-CNS solid tumors were prospectively enrolled in the BASIC3 study at a large academic children's hospital during a 23-month period from August 2012 through June 2014. Blood and tumor samples underwent WES in a certified clinical laboratory with genetic results categorized on the basis of perceived clinical relevance and entered in the electronic health record.

MAIN OUTCOMES AND MEASURES: Clinical categorization of somatic mutations; frequencies of deleterious germline mutations related to patient phenotype and incidental medically-actionable mutations.

RESULTS: Of the first 150 participants (80 boys and 70 girls, mean age, 7.4 years), tumor samples adequate for WES were available from 121 patients (81%). Somatic mutations of established clinical utility (category I) were reported in 4 (3%) of 121 patients, with mutations of potential utility (category II) detected in an additional 29 (24%) of 121 patients. CTNNB1 was the gene most frequently mutated, with recurrent mutations in KIT, TSC2, and MAPK pathway genes (BRAF, KRAS, and NRAS) also identified. Mutations in consensus cancer genes (category III) were found in an additional 24 (20%) of 121 tumors. Fewer than half of somatic mutations identified were in genes known to be recurrently mutated in the tumor type tested. Diagnostic germline findings related to patient phenotype were discovered in 15 (10%) of 150 cases: 13 pathogenic or likely pathogenic dominant mutations in adult and pediatric cancer susceptibility genes (including 2 each in TP53, VHL, and BRCA1), 1 recessive liver disorder with hepatocellular carcinoma (TJP2), and 1 renal diagnosis (CLCN5). Incidental findings were reported in 8 (5%) of 150 patients. Most patients harbored germline uncertain variants in cancer genes (98%), pharmacogenetic variants (89%), and recessive carrier mutations (85%).

CONCLUSIONS AND RELEVANCE: Tumor and germline WES revealed mutations in a broad spectrum of genes previously implicated in both adult and pediatric cancers. Combined reporting of tumor and germline WES identified diagnostic and/or potentially actionable findings in nearly 40% of newly diagnosed pediatric patients with solid tumors.

%B JAMA Oncol %V 2 %P 616-624 %8 2016 May 01 %G eng %N 5 %1 https://www.ncbi.nlm.nih.gov/pubmed/26822237?dopt=Abstract %R 10.1001/jamaoncol.2015.5699 %0 Journal Article %J Genome Med %D 2014 %T Obtaining informed consent for clinical tumor and germline exome sequencing of newly diagnosed childhood cancer patients. %A Scollon, Sarah %A Bergstrom, Katie %A Kerstein, Robin A %A Wang, Tao %A Hilsenbeck, Susan G %A Ramamurthy, Uma %A Richard A Gibbs %A Eng, Christine M %A Chintagumpala, Murali M %A Berg, Stacey L %A McCullough, Laurence B %A McGuire, Amy L %A Plon, Sharon E %A Parsons, D Williams %X

BACKGROUND: Effectively educating families about the risks and benefits of genomic tests such as whole exome sequencing (WES) offers numerous challenges, including the complexity of test results and potential loss of privacy. Research on best practices for obtaining informed consent (IC) in a variety of clinical settings is needed. The BASIC3 study of clinical tumor and germline WES in an ethnically diverse cohort of newly diagnosed pediatric cancer patients offers the opportunity to study the IC process in the setting of critical illness. We report on our experience for the first 100 families enrolled, including study participation rates, reasons for declining enrollment, assessment of clinical and demographic factors that might impact study enrollment, and preferences of parents for participation in optional genomics study procedures.

METHODS: A specifically trained IC team offered study enrollment to parents of eligible children for procedures including clinical tumor and germline WES with results deposited in the medical record and disclosure of both diagnostic and incidental results to the family. Optional study procedures were also offered, such as receiving recessive carrier status and deposition of data into research databases. Stated reasons for declining participation were recorded. Clinical and demographic data were collected and comparisons made between enrolled and non-enrolled patients.

RESULTS: Over 15 months, 100 of 121 (83%) eligible families elected to enroll in the study. No significant differences in enrollment were detected based on factors such as race, ethnicity, use of Spanish interpreters and Spanish consent forms, and tumor features (central nervous system versus non-central nervous system, availability of tumor for WES). The most common reason provided for declining enrollment (10% of families) was being overwhelmed by the new cancer diagnosis. Risks specific to clinical genomics, such as privacy concerns, were less commonly reported (5.5%). More than 85% of parents consented to each of the optional study procedures.

CONCLUSIONS: An IC process was developed that utilizes a specialized IC team, active communication with the oncology team, and an emphasis on scheduling flexibility. Most parents were willing to participate in a clinical germline and tumor WES study as well as optional procedures such as genomic data sharing independent of race, ethnicity or language spoken.

%B Genome Med %V 6 %P 69 %8 2014 %G eng %N 9 %1 https://www.ncbi.nlm.nih.gov/pubmed/25317207?dopt=Abstract %R 10.1186/s13073-014-0069-3 %0 Journal Article %J J Natl Cancer Inst %D 2011 %T Loss of Rho GDIα and resistance to tamoxifen via effects on estrogen receptor α. %A Barone, Ines %A Brusco, Lauren %A Gu, Guowei %A Selever, Jennifer %A Beyer, Amanda %A Covington, Kyle R %A Tsimelzon, Anna %A Wang, Tao %A Hilsenbeck, Susan G %A Chamness, Gary C %A Andò, Sebastiano %A Fuqua, Suzanne A W %K Animals %K Antineoplastic Agents, Hormonal %K Breast Neoplasms %K Cell Line, Tumor %K Down-Regulation %K Drug Resistance, Neoplasm %K Enzyme Activation %K Estrogen Antagonists %K Estrogen Receptor alpha %K Female %K Gene Expression Regulation, Neoplastic %K Gene Silencing %K Genome-Wide Association Study %K Guanine Nucleotide Dissociation Inhibitors %K Histone Deacetylases %K Humans %K Immunoblotting %K Immunohistochemistry %K Immunoprecipitation %K Mice %K Mice, Nude %K Neoplasm Recurrence, Local %K Odds Ratio %K Phenotype %K Plasmids %K Protein Array Analysis %K Random Allocation %K Repressor Proteins %K Retrospective Studies %K rho GTP-Binding Proteins %K rho Guanine Nucleotide Dissociation Inhibitor alpha %K rho-Specific Guanine Nucleotide Dissociation Inhibitors %K RNA, Small Interfering %K Secondary Prevention %K Selective Estrogen Receptor Modulators %K Signal Transduction %K Tamoxifen %K Time Factors %K Transcriptional Activation %K Transplantation, Heterologous %K Tumor Stem Cell Assay %X

BACKGROUND: Estrogen receptor (ER) α is a successful therapeutic target in breast cancer, but patients eventually develop resistance to antiestrogens such as tamoxifen.

METHODS: To identify genes whose expression was associated with the development of tamoxifen resistance and metastasis, we used microarrays to compare gene expression in four primary tumors from tamoxifen-treated patients whose breast cancers did not recur vs five metastatic tumors from patients whose cancers progressed during adjuvant tamoxifen treatment. Because Rho guanine dissociation inhibitor (GDI) α was underexpressed in the tamoxifen-resistant group, we stably transfected ERα-positive MCF-7 breast cancer cells with a plasmid encoding a short hairpin (sh) RNA to silence Rho GDIα expression. We used immunoblots and transcription assays to examine the role of Rho GDIα in ER-related signaling and growth of cells in vitro and as xenografts in treated nude mice (n = 8-9 per group) to examine the effects of Rho GDIα blockade on hormone responsiveness and metastatic behavior. The time to tumor tripling as the time in weeks from randomization to a threefold increase in total tumor volume over baseline was examined in treated mice. The associations of Rho GDIα and MTA2 levels with tamoxifen resistance were examined in microarray data from patients. All statistical tests were two-sided.

RESULTS: Rho GDIα was expressed at lower levels in ERα-positive tumors that recurred during tamoxifen treatment than in ERα-positive tamoxifen-sensitive primary tumors. MCF-7 breast cancer cells in which Rho GDIα expression had been silenced were tamoxifen-resistant, had increased Rho GTPase and p21-activated kinase 1 activity, increased phosphorylation of ERα at serine 305, and enhanced tamoxifen-induced ERα transcriptional activity compared with control cells. MCF-7 cells in which Rho GDIα expression was silenced metastasized with high frequency when grown as tumor xenografts. When mice were treated with estrogen or estrogen withdrawal, tripling times for xenografts from cells with Rho GDIα silencing were similar to those from vector-containing control cells; however, tripling times were statistically significantly faster than control when mice were treated with tamoxifen (median tripling time for tumors with Rho GDIα small interfering RNA = 2.34 weeks; for control tumors = not reached, hazard ratio = 4.13, 95% confidence interval = 1.07 to 15.96, P = .040 [adjusted for multiple comparisons, P = .119]). Levels of the metastasis-associated protein MTA2 were also increased upon Rho GDIα silencing, and combined Rho GDIα and MTA2 levels were associated with recurrence in 250 tamoxifen-treated patients.

CONCLUSION: Loss of Rho GDIα enhances metastasis and resistance to tamoxifen via effects on both ERα and MTA2 in models of ERα-positive breast cancer and in tumors of tamoxifen-treated patients.

%B J Natl Cancer Inst %V 103 %P 538-52 %8 2011 Apr 06 %G eng %N 7 %1 https://www.ncbi.nlm.nih.gov/pubmed/21447808?dopt=Abstract %R 10.1093/jnci/djr058