title: Cell adhesion induces p27Kip1-associated cell-cycle arrest through down-regulation of the SCFSkp2 ubiquitin ligase pathway in mantle-cell and other non-Hodgkin B-cell lymphomas.
abstract: Mounting evidence suggests that dynamic interactions between a tumor and its microenvironment play a critical role in tumor development, cell-cycle progression, and response to therapy. In this study, we used mantle cell lymphoma (MCL) as a model to characterize the mechanisms by which stroma regulate cell-cycle progression. We demonstrated that adhesion of MCL and other non-Hodgkin lymphoma (NHL) cells to bone marrow stromal cells resulted in a reversible G(1) arrest associated with elevated p27(Kip1) and p21 (WAF1) proteins. The adhesion-mediated p27(Kip1) and p21 increases were posttranslationally regulated via the down-regulation of Skp2, a subunit of SCF(Skp2) ubiquitin ligase. Overexpression of Skp2 in MCL decreased p27(Kip1), whereas inhibition of Skp2 by siRNA increased p27(Kip1) and p21 levels. Furthermore, we found cell adhesion up-regulated Cdh1 (an activating subunit of anaphase-promoting complex [APC] ubiquitin ligase), and reduction of Cdh1 by siRNA induced Skp2 accumulation and hence p27(Kip1) degradation, thus implicating Cdh1 as an upstream effector of the Skp2/p27(Kip1) signaling pathway. Overall, this report, for the first time, demonstrates that cell-cell contact controls the tumor cell cycle via ubiquitin-proteasome proteolytic pathways in MCL and other NHLs. The understanding of this novel molecular pathway may prove valuable in designing new therapeutic approaches for modifying tumor cell growth and response to therapy.
authors.affiliation: Department of Interdisciplinary Oncology and Experimental Therapeutics Program, H. Lee Moffitt Cancer Center and Research Institute at the University of South Florida, Tampa, FL 33613, USA.
authors.forename: Tint
authors.initials: T
authors.lastname: Lwin
authors.forename: Lori A
authors.initials: LA
authors.lastname: Hazlehurst
authors.forename: Sophie
authors.initials: S
authors.lastname: Dessureault
authors.forename: Raymond
authors.initials: R
authors.lastname: Lai
authors.forename: Wenlong
authors.initials: W
authors.lastname: Bai
authors.forename: Eduardo
authors.initials: E
authors.lastname: Sotomayor
authors.forename: Lynn C
authors.initials: LC
authors.lastname: Moscinski
authors.forename: William S
authors.initials: WS
authors.lastname: Dalton
authors.forename: Jianguo
authors.initials: J
authors.lastname: Tao
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D015703:Antigens, CD; D001854:Bone Marrow Cells / Q000378:metabolism* / Q000473:pathology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016193:G1 Phase / Q000187:drug effects / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016393:Lymphoma, B-Cell / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D020522:Lymphoma, Mantle-Cell / Q000201:enzymology* / Q000235:genetics / Q000473:pathology / Q000628:therapy; D008954:Models, Biological; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism / Q000494:pharmacology; D044786:S-Phase Kinase-Associated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; C493956:CDKN1A protein, human; C436291:CDKN1B protein, human; D015820:Cadherins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; D044786:S-Phase Kinase-Associated Proteins; D025801:Ubiquitin; D050760:Cyclin-Dependent Kinase Inhibitor p27; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D046988:Proteasome Endopeptidase Complex