title: The multidrug transporter P-glycoprotein: a mediator of melanoma invasion?
abstract: Malignant melanoma shows high levels of intrinsic drug resistance associated with a highly invasive phenotype. In this study, we investigated the role of the drug transporter P-glycoprotein (Pgp) in the invasion potential of drug-sensitive (M14 WT, Pgp-negative) and drug-resistant (M14 ADR, Pgp-positive) human melanoma cells. Coimmunoprecipitation experiments assessed the association of Pgp with the adhesion molecule CD44 in multidrug resistant (MDR) melanoma cells, compared with parental ones. In MDR cells, the two proteins colocalized in the plasma membrane as visualized by confocal microscopy and immunoelectron microscopy on ultrathin cryosections. MDR melanoma cells displayed a more invasive phenotype compared with parental cells, as demonstrated by quantitative transwell chamber invasion assay. This was accomplished by a different migration strategy adopted by resistant cells ("chain collective") previously described in tumor cells with high metastatic capacity. The Pgp molecule, after stimulation with specific antibodies, appeared to cooperate with CD44, through the activation of ERK1/2 and p38 mitogen-activated protein kinase (MAPK) proteins. This activation led to an increase of metalloproteinase (MMP-2, MMP-3, and MMP-9) mRNAs, and proteolytic activities, which are associated with an increased invasive behavior. RNA interference experiments further demonstrated Pgp involvement in migration and invasion of resistant melanoma cells. A link was identified between MDR transporter Pgp, and MAPK signaling and invasion.
authors.affiliation: Department of Technology and Health, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Marisa
authors.initials: M
authors.lastname: Colone
authors.forename: Annarica
authors.initials: A
authors.lastname: Calcabrini
authors.forename: Laura
authors.initials: L
authors.lastname: Toccacieli
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Bozzuto
authors.forename: Annarita
authors.initials: A
authors.lastname: Stringaro
authors.forename: Massimo
authors.initials: M
authors.lastname: Gentile
authors.forename: Maurizio
authors.initials: M
authors.lastname: Cianfriglia
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ciervo
authors.forename: Michele
authors.initials: M
authors.lastname: Caraglia
authors.forename: Alfredo
authors.initials: A
authors.lastname: Budillon
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Meo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arancia
authors.forename: Agnese
authors.initials: A
authors.lastname: Molinari
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis / Q000378:metabolism; D047468:Immunoprecipitation; D020930:MAP Kinase Kinase Kinases; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism / Q000473:pathology*; D009361:Neoplasm Invasiveness; D034622:RNA Interference; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D018960:Hyaluronan Receptors; D020930:MAP Kinase Kinase Kinases; D020782:Matrix Metalloproteinases