title: Identification of V-ATPase as a molecular sensor of SOX11-levels and potential therapeutic target for mantle cell lymphoma.
abstract: Mantle cell lymphoma (MCL) is an aggressive disease with short median survival. Molecularly, MCL is defined by the t(11;14) translocation leading to overexpression of the CCND1 gene. However, recent data show that the neural transcription factor SOX11 is a disease defining antigen and several involved signaling pathways have been pin-pointed, among others the Wnt/β-catenin pathway that is of importance for proliferation in MCL. Therefore, we evaluated a compound library focused on the Wnt pathway with the aim of identifying Wnt-related targets that regulate growth and survival in MCL, with particular focus on SOX11-dependent growth regulation.
  
  
  
  An inducible SOX11 knock-down system was used to functionally screen a library of compounds (n = 75) targeting the Wnt signaling pathway. A functionally interesting target, vacuolar-type H(+)-ATPase (V-ATPase), was further evaluated by western blot, siRNA-mediated gene silencing, immunofluorescence, and flow cytometry.
  
  
  
  We show that 15 out of 75 compounds targeting the Wnt pathway reduce proliferation in all three MCL cell lines tested. Furthermore, three substances targeting two different targets (V-ATPase and Dkk1) showed SOX11-dependent activity. Further validation analyses were focused on V-ATPase and showed that two independent V-ATPase inhibitors (bafilomycin A1 and concanamycin A) are sensitive to SOX11 levels, causing reduced anti-proliferative response in SOX11 low cells. We further show, using fluorescence imaging and flow cytometry, that V-ATPase is mainly localized to the plasma membrane in primary and MCL cell lines.
  
  
  
  We show that SOX11 status affect V-ATPase dependent pathways, and thus may be involved in regulating pH in intracellular and extracellular compartments. The plasma membrane localization of V-ATPase indicates that pH regulation of the immediate extracellular compartment may be of importance for receptor functionality and potentially invasiveness in vivo.
authors.affiliation: Department of Immunotechnology, Lund University, Medicon Village, Scheelevägen 8, 223 87, Lund, Sweden.
authors.forename: Venera Kuci
authors.initials: VK
authors.lastname: Emruli
authors.affiliation: Department of Experimental Medical Science, Chemical Biology & Therapeutics, Lund University, Lund, Sweden.
authors.forename: Roger
authors.initials: R
authors.lastname: Olsson
authors.affiliation: Department of Experimental Medical Science, Chemical Biology & Therapeutics, Lund University, Lund, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Ek
authors.affiliation: Department of Immunotechnology, Lund University, Medicon Village, Scheelevägen 8, 223 87, Lund, Sweden. sara.ek@immun.lth.se.
authors.forename: Sara
authors.initials: S
authors.lastname: Ek
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019938:Cyclin D1 / Q000235:genetics; D000077209:Decitabine; D004318:Doxycycline / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D020522:Lymphoma, Mantle-Cell / Q000188:drug therapy*; D018942:Macrolides / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D055751:SOXC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics*; D051153:Wnt Proteins / Q000037:antagonists & inhibitors; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D051176:beta Catenin / Q000037:antagonists & inhibitors
chemical_list: C530104:CCND1 protein, human; C501126:DKK1 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D018942:Macrolides; D008565:Membrane Proteins; D034741:RNA, Small Interfering; C097473:SOX11 protein, human; D055751:SOXC Transcription Factors; D051153:Wnt Proteins; D051176:beta Catenin; C057620:bafilomycin A; D019938:Cyclin D1; D000077209:Decitabine; C036978:concanamycin A; D025262:Vacuolar Proton-Translocating ATPases; D001374:Azacitidine; D004318:Doxycycline
keywords: Mantle cell lymphoma; SOX11; V-ATPase