title: The prostate metastasis suppressor gene NDRG1 differentially regulates cell motility and invasion.
abstract: Experimental and clinical evidence suggests that N-myc downregulated gene 1 (NDRG1) functions as a suppressor of prostate cancer metastasis. Elucidating pathways that drive survival and invasiveness of NDRG1-deficient prostate cancer cells can help in designing therapeutics to target metastatic prostate cancer cells. However, the molecular mechanisms that lead NDRG1-deficient prostate cancer cells to increased invasiveness remain largely unknown. In this study, we demonstrate that NDRG1-deficient prostate tumors have decreased integrin expression and reduced cell adhesion and motility. Our data indicate that loss of NDRG1 differentially affects Rho GTPases. Specifically, there is a downregulation of active RhoA and Rac1 GTPases with a concomitant upregulation of active Cdc42 in NDRG1-deficient cells. Live cell imaging using a fluorescent sensor that binds to polymerized actin revealed that NDRG1-deficient cells have restricted actin dynamics, thereby affecting cell migration. These cellular and molecular characteristics are in sharp contrast to what is expected after loss of a metastasis suppressor. We further demonstrate that NDRG1-deficient cells have increased resistance to anoikis and increased invasiveness which is independent of its elevated Cdc42 activity. Furthermore, NDRG1 regulates expression and glycosylation of EMMPRIN, a master regulator of matrix metalloproteases. NDRG1 deficiency leads to an increase in EMMPRIN expression with a concomitant increase in matrix metalloproteases and thus invadopodial activity. Using a three-dimensional invasion assay and an in vivo metastasis assay for human prostate xenografts, we demonstrate that NDRG1-deficient prostate cancer cells exhibit a collective invasion phenotype and are highly invasive. Thus, our findings provide novel insights suggesting that loss of NDRG1 leads to a decrease in actin-mediated cellular motility but an increase in cellular invasion, resulting in increased tumor dissemination which positively impacts metastatic outcome.
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Anup
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Mendonca
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: James
authors.initials: J
authors.lastname: Ying
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Hea-Soo
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Verdone
authors.affiliation: Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Jelani C
authors.initials: JC
authors.lastname: Zarif
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Carducci
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Hans
authors.initials: H
authors.lastname: Hammers
authors.affiliation: Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Pienta
authors.affiliation: Prostate Cancer Program, Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Medical Institutions, Baltimore, MD, USA.
authors.forename: Sushant
authors.initials: S
authors.lastname: Kachhap
mesh_terms: D000818:Animals; D023102:Anoikis / Q000502:physiology; D051926:Basigin / Q000378:metabolism; D002448:Cell Adhesion; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D057809:HEK293 Cells; D006801:Humans; D016023:Integrins / Q000172:deficiency; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D051926:Basigin; D018797:Cell Cycle Proteins; D016023:Integrins; D047908:Intracellular Signaling Peptides and Proteins; D020782:Matrix Metalloproteinases; D025521:Tumor Suppressor Proteins; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein; D000099259:N-myc Downstream-Regulated Gene 1 Protein; C497886:BSG protein, human; C581598:Cdc42 protein, mouse; C107953:RAC1 protein, human; C066737:RHOA protein, human
keywords: actin cytoskeleton; matrix metalloproteases; metastasis; prostate cancer