Browsing by Author "Lin, Xi"

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    Delineating the molecular and phenotypic spectrum of the SETD1B-related syndrome
    (Elsevier, 2021-11) Weerts, Marjolein J.A.; Lanko, Kristina; Guzmán-Vega, Francisco J.; Jackson, Adam; Ramakrishnan, Reshmi; Cardona-Londoño, Kelly J.; Peña-Guerra, Karla A.; van Bever, Yolande; van Paassen, Barbara W.; Kievit, Anneke; van Slegtenhorst, Marjon; Allen, Nicholas M.; Kehoe, Caroline M.; Robinson, Hannah K.; Pang, Lewis; Banu, Selina H.; Zaman, Mashaya; Efthymiou, Stephanie; Houlden, Henry; Järvelä, Irma; Lauronen, Leena; Määttä, Tuomo; Schrauwen, Isabelle; Leal, Suzanne M.; Ruivenkamp, Claudia A.L.; Barge-Schaapveld, Daniela Q.C.M.; Peeters-Scholte, Cacha M.P.C.D.; Galehdari, Hamid; Mazaheri, Neda; Sisodiya, Sanjay M.; Harrison, Victoria; Sun, Angela; Thies, Jenny; Pedroza, Luis Alberto; Lara-Taranchenko, Yana; Chinn, Ivan K.; Lupski, James R.; Garza-Flores, Alexandra; McGlothlin, Jeffery; Yang, Lin; Huang, Shaoping; Wang, Xiaodong; Jewett, Tamison; Rosso, Gretchen; Lin, Xi; Mohammed, Shehla; Merritt, J. Lawrence, II.; Mirzaa, Ghayda M.; Timms, Andrew E.; Scheck, Joshua; Elting, Mariet W.; Polstra, Abeltje M.; Schenck, Lauren; Ruzhnikov, Maura R.Z.; Vetro, Annalisa; Montomoli, Martino; Guerrini, Renzo; Koboldt, Daniel C.; Mihalic Mosher, Theresa; Pastore, Matthew T.; McBride, Kim L.; Peng, Jing; Pan, Zou; Willemsen, Marjolein; Koning, Susanne; Turnpenny, Peter D.; de Vries, Bert B.A.; Gilissen, Christian; Pfundt, Rolph; Lees, Melissa; Braddock, Stephen R.; Klemp, Kara C.; Vansenne, Fleur; van Gijn, Marielle E.; Quindipan, Catherine; Deardorff, Matthew A.; Hamm, J. Austin; Putnam, Abbey M.; Baud, Rebecca; Walsh, Laurence; Lynch, Sally A.; Baptista, Julia; Person, Richard E.; Monaghan, Kristin G.; Crunk, Amy; Keller-Ramey, Jennifer; Reich, Adi; Elloumi, Houda Zghal; Alders, Marielle; Kerkhof, Jennifer; McConkey, Haley; Haghshenas, Sadegheh; Maroofian, Reza; Sadikovic, Bekim; Banka, Siddharth; Arold, Stefan T.; Barakat, Tahsin Stefan; Medical and Molecular Genetics, School of Medicine
    Purpose: Pathogenic variants in SETD1B have been associated with a syndromic neurodevelopmental disorder including intellectual disability, language delay, and seizures. To date, clinical features have been described for 11 patients with (likely) pathogenic SETD1B sequence variants. This study aims to further delineate the spectrum of the SETD1B-related syndrome based on characterizing an expanded patient cohort. Methods: We perform an in-depth clinical characterization of a cohort of 36 unpublished individuals with SETD1B sequence variants, describing their molecular and phenotypic spectrum. Selected variants were functionally tested using in vitro and genome-wide methylation assays. Results: Our data present evidence for a loss-of-function mechanism of SETD1B variants, resulting in a core clinical phenotype of global developmental delay, language delay including regression, intellectual disability, autism and other behavioral issues, and variable epilepsy phenotypes. Developmental delay appeared to precede seizure onset, suggesting SETD1B dysfunction impacts physiological neurodevelopment even in the absence of epileptic activity. Males are significantly overrepresented and more severely affected, and we speculate that sex-linked traits could affect susceptibility to penetrance and the clinical spectrum of SETD1B variants. Conclusion: Insights from this extensive cohort will facilitate the counseling regarding the molecular and phenotypic landscape of newly diagnosed patients with the SETD1B-related syndrome.
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    Preclinical characterization of the CDK4/6 inhibitor LY2835219: in-vivo cell cycle-dependent/independent anti-tumor activities alone/in combination with gemcitabine
    (Springer, 2014) Gelbert, Lawrence M.; Cai, Shufen; Lin, Xi; Sanchez-Martinez, Concepcion; del Prado, Miriam; Lallena, Maria Jose; Torres, Raquel; Ajamie, Rose T.; Wishart, Graham N.; Flack, Robert Steven; Neubauer, Blake Lee; Young, Jamie; Chan, Edward M.; Iversen, Philip; Cronier, Damien; Kreklau, Emiko; de Dios, Alfonso; Pediatrics, School of Medicine
    The G1 restriction point is critical for regulating the cell cycle and is controlled by the Rb pathway (CDK4/6-cyclin D1-Rb-p16/ink4a). This pathway is important because of its inactivation in a majority of human tumors. Transition through the restriction point requires phosphorylation of retinoblastoma protein (Rb) by CDK4/6, which are highly validated cancer drug targets. We present the identification and characterization of a potent CDK4/6 inhibitor, LY2835219. LY2835219 inhibits CDK4 and CDK6 with low nanomolar potency, inhibits Rb phosphorylation resulting in a G1 arrest and inhibition of proliferation, and its activity is specific for Rb-proficient cells. In vivo target inhibition studies show LY2835219 is a potent inhibitor of Rb phosphorylation, induces a complete cell cycle arrest and suppresses expression of several Rb-E2F-regulated proteins 24 hours after a single dose. Oral administration of LY2835219 inhibits tumor growth in human tumor xenografts representing different histologies in tumor-bearing mice. LY2835219 is effective and well tolerated when administered up to 56 days in immunodeficient mice without significant loss of body weight or tumor outgrowth. In calu-6 xenografts, LY2835219 in combination with gemcitabine enhanced in vivo antitumor activity without a G1 cell cycle arrest, but was associated with a reduction of ribonucleotide reductase expression. These results suggest LY2835219 may be used alone or in combination with standard-of-care cytotoxic therapy. In summary, we have identified a potent, orally active small-molecule inhibitor of CDK4/6 that is active in xenograft tumors. LY2835219 is currently in clinical development.
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    Rnd3/RhoE Modulates HIF1α/VEGF Signaling by Stabilizing HIF1α and Regulates Responsive Cardiac Angiogenesis
    (American Heart Association, 2016-03) Yue, Xiaojing; Yang, Tingli; Lin, Xi; Yang, Xiangsheng; Yi, Xin; Jiang, Xuejun; Li, Xiaoyan; Li, Tianfa; Guo, Junli; Dai, Yuan; Shi, Jianjian; Wei, Lei; Youker, Keith A.; Torre-Amione, Guillermo; Yu, Yanhong; Andrade, Kelsey C.; Chang, Jiang; Department of Pediatrics, IU School of Medicine
    The insufficiency of compensatory angiogenesis in the heart of patients with hypertension contributes to heart failure transition. The hypoxia-inducible factor 1α-vascular endothelial growth factor (HIF1α-VEGF) signaling cascade controls responsive angiogenesis. One of the challenges in reprograming the insufficient angiogenesis is to achieve a sustainable tissue exposure to the proangiogenic factors, such as HIF1α stabilization. In this study, we identified Rnd3, a small Rho GTPase, as a proangiogenic factor participating in the regulation of the HIF1α-VEGF signaling cascade. Rnd3 physically interacted with and stabilized HIF1α, and consequently promoted VEGFA expression and endothelial cell tube formation. To demonstrate this proangiogenic role of Rnd3 in vivo, we generated Rnd3 knockout mice. Rnd3 haploinsufficient (Rnd3(+/-)) mice were viable, yet developed dilated cardiomyopathy with heart failure after transverse aortic constriction stress. The poststress Rnd3(+/-) hearts showed significantly impaired angiogenesis and decreased HIF1α and VEGFA expression. The angiogenesis defect and heart failure phenotype were partially rescued by cobalt chloride treatment, a HIF1α stabilizer, confirming a critical role of Rnd3 in stress-responsive angiogenesis. Furthermore, we generated Rnd3 transgenic mice and demonstrated that Rnd3 overexpression in heart had a cardioprotective effect through reserved cardiac function and preserved responsive angiogenesis after pressure overload. Finally, we assessed the expression levels of Rnd3 in the human heart and detected significant downregulation of Rnd3 in patients with end-stage heart failure. We concluded that Rnd3 acted as a novel proangiogenic factor involved in cardiac responsive angiogenesis through HIF1α-VEGFA signaling promotion. Rnd3 downregulation observed in patients with heart failure may explain the insufficient compensatory angiogenesis involved in the transition to heart failure.