title: Overexpression of caveolin-1 in lymphoblastoid TK6 cells enhances proliferation after irradiation with clinically relevant doses.
abstract: OBJECTIVE
  The transmembrane protein caveolin-1 (CAV1) is an essential component of caveolae, small membrane invaginations involved in vesicle formation. CAV1 plays a role in signal transduction, tumor suppression and oncogene transformation. Previous studies with CAV1 knockout mice and CAV1 knockdown in pancreatic tumor cells implicated CAV1 in mediating radioresistance. The aim of this work was to test the effect of CAV1 overexpression after irradiation in human cells lacking endogenous CAV1 expression.
  
  
  METHODS
  Human CAV1 was overexpressed in lymphoblastoid TK6 cells (TK6-wt) using a eukaryotic expression plasmid, pCI-CAV1, or a lentiviral SIN (self-inactivating) vector, HR'SIN-CAV1. CAV1 expression was verified in TK6 cells with Western blot analysis or intracellular FACS (fluorescence-activated cell sorting) staining. The effect of CAV1 on proliferation kinetics after irradiation of TK6 cells was measured with a growth assay.
  
  
  RESULTS
  TK6-wt showed no detectable endogenous CAV1 expression. Lentivirally mediated transduction with HR'SIN-CAV1 (TK6-CAV1) resulted in a considerably stronger CAV1 expression in comparison to TK6 cells electroporated with pCI-CAV1. Intracellular FACS analysis showed that 90% of transduced cells expressed CAV1. CAV1 enhanced early proliferation of TK6 cells after irradiation with a dose of 2 Gy, whereas proliferation of unirradiated cells was not affected. CAV1 also protected cells after irradiation with 4 Gy. This radioprotective effect was supported by a reduction of radiation-induced apoptosis.
  
  
  CONCLUSIONS
  A model system for expression of exogenous CAV1 by stable lentiviral transduction of TK6 cells was established. Functional assays demonstrated enhanced early proliferation by CAV1 expression in TK6 cells after irradiation with clinically relevant doses supporting the role of CAV1 as a prosurvival factor.
authors.affiliation: Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany. david.barzan@medma.uni-heidelberg.de.|Klinik für Strahlentherapie und Radioonkologie, UMM, Universitätsmedizin Mannheim, Theodor-Kutzer-Ufer 1-3, 68153, Mannheim, Germany. david.barzan@medma.uni-heidelberg.de.
authors.forename: David
authors.initials: D
authors.lastname: Barzan
authors.affiliation: Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Maier
authors.affiliation: Pharmacology of Cancer Treatment, German Cancer Research Center, Heidelberg, Germany.
authors.forename: W Jens
authors.initials: WJ
authors.lastname: Zeller
authors.affiliation: Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Wenz
authors.affiliation: Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany. carsten.herskind@medma.uni-heidelberg.de.|Klinik für Strahlentherapie und Radioonkologie, UMM, Universitätsmedizin Mannheim, Theodor-Kutzer-Ufer 1-3, 68153, Mannheim, Germany. carsten.herskind@medma.uni-heidelberg.de.
authors.forename: Carsten
authors.initials: C
authors.lastname: Herskind
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000528:radiation effects*; D015153:Blotting, Western; D051242:Caveolin 1 / Q000235:genetics*; D002455:Cell Division / Q000235:genetics / Q000528:radiation effects*; D045744:Cell Line, Tumor; D004307:Dose-Response Relationship, Radiation; D005434:Flow Cytometry; D015870:Gene Expression / Q000235:genetics / Q000528:radiation effects*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D008214:Lymphocytes / Q000378:metabolism / Q000528:radiation effects; D010957:Plasmids; D011835:Radiation Protection; D014161:Transduction, Genetic / Q000379:methods
chemical_list: D051242:Caveolin 1