title: Proteomic analysis reveals a novel role for the actin cytoskeleton in vincristine resistant childhood leukemia--an in vivo study.
abstract: Intrinsic or acquired resistance to vincristine (VCR), an antimicrotubule agent used in the treatment of childhood acute lymphoblastic leukemia (ALL), is a major clinical problem. Using a clinically relevant NOD/SCID mouse xenograft model of ALL, we established that alterations in the actin and tubulin cytoskeleton are involved in in vivo VCR resistance. Altered protein expression between VCR-sensitive ALL xenografts, and xenografts with intrinsic or acquired VCR resistance, was identified using 2-D DIGE coupled with MS. Of the 19 proteins displaying altered expression, 11 are associated with the actin cytoskeleton. Altered expression of the actin- and/or tubulin-binding proteins gelsolin, moesin, ezrin, tropomyosin, CAP-G, HSP27, HSP70, TCP-1, and stathmin were associated with in vivo VCR resistance. The actin-regulating protein gelsolin was increased in both acquired and resistant leukemia as confirmed by immunoblotting and gene expression. The major cytoskeletal protein, gamma-actin, was down-regulated in the VCR-resistant leukemia xenografts; in contrast, there was no significant change in beta-actin expression. This study provides the first evidence for a role of the actin cytoskeleton in intrinsic and acquired in vivo antimicrotubule drug resistance in childhood leukemia and highlights the power of 2-D DIGE for the discovery of resistance markers, pharmacoproteomics, and signaling pathways in cancer.
authors.affiliation: Children's Cancer Institute Australia for Medical Research, Randwick, NSW, Australia.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Verrills
authors.forename: Natalia L
authors.initials: NL
authors.lastname: Liem
authors.forename: Tracy Y E
authors.initials: TY
authors.lastname: Liaw
authors.forename: Brian D
authors.initials: BD
authors.lastname: Hood
authors.forename: Richard B
authors.initials: RB
authors.lastname: Lock
authors.forename: Maria
authors.initials: M
authors.lastname: Kavallaris
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use*; D002648:Child; D003599:Cytoskeleton / Q000737:chemistry / Q000378:metabolism*; D019008:Drug Resistance, Neoplasm; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D051379:Mice; D016513:Mice, SCID; D008868:Microtubule Proteins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000378:metabolism; D020543:Proteome / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014183:Transplantation, Heterologous; D014750:Vincristine
chemical_list: D000199:Actins; D000972:Antineoplastic Agents, Phytogenic; D008868:Microtubule Proteins; D020543:Proteome; D014750:Vincristine