Linker for Activation of T-cell Family Member2 (LAT2) a Lipid Raft Adaptor Protein for AKT Signaling, Is an Early Mediator of Alkylphospholipid Anti-leukemic Activity


Autoria(s): Thome, Carolina H.; Santos, Guilherme A. dos; Ferreira, Germano A.; Scheucher, Priscila S.; Izumi, Clarice; Leopoldino, Andreia M.; Simao, Ana Maria; Ciancaglini, Pietro; Oliveira, Kleber T. de; Chin, Alice; Hanash, Samir M.; Falcao, Roberto P.; Rego, Eduardo M.; Greene, Lewis J.; Faca, Vitor M.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/09/2013

20/09/2013

2012

Resumo

Lipid rafts are highly ordered membrane domains rich in cholesterol and sphingolipids that provide a scaffold for signal transduction proteins; altered raft structure has also been implicated in cancer progression. We have shown that 25 mu M 10-(octyloxy) decyl-2-(trimethylammonium) ethyl phosphate (ODPC), an alkylphospholipid, targets high cholesterol domains in model membranes and induces apoptosis in leukemia cells but spares normal hematopoietic and epithelial cells under the same conditions. We performed a quantitative (SILAC) proteomic screening of ODPC targets in a lipid-raft-enriched fraction of leukemic cells to identify early events prior to the initiation of apoptosis. Six proteins, three with demonstrated palmitoylation sites, were reduced in abundance. One, the linker for activation of T-cell family member 2 (LAT2), is an adaptor protein associated with lipid rafts in its palmitoylated form and is specifically expressed in B lymphocytes and myeloid cells. Interestingly, LAT2 is not expressed in K562, a cell line more resistant to ODPC-induced apoptosis. There was an early loss of LAT2 in the lipid-raft-enriched fraction of NB4 cells within 3 h following treatment with 25 mu M ODPC. Subsequent degradation of LAT2 by proteasomes was observed. Twenty-five mu M ODPC inhibited AKT activation via myeloid growth factors, and LAT2 knockdown in NB4 cells by shRNA reproduced this effect. LAT2 knockdown in NB4 cells also decreased cell proliferation and increased cell sensitivity to ODPC (7.5X), perifosine (3X), and arsenic trioxide (8.5X). Taken together, these data indicate that LAT2 is an early mediator of the anti-leukemic activity of alkylphospholipids and arsenic trioxide. Thus, LAT2 may be used as a target for the design of drugs for cancer therapy. Molecular & Cellular Proteomics 11: 10.1074/mcp.M112.019661, 1898-1912, 2012.

FAPESP [07/58649-1, 2011/07387-2, 2011/09718-6]

FAPESP

FINEP

FINEP

CNPq

CNPq

CAPES

CAPES

Identificador

MOLECULAR & CELLULAR PROTEOMICS, BETHESDA, v. 11, n. 12, Special Issue, pp. 1898-1912, DEC, 2012

1535-9476

http://www.producao.usp.br/handle/BDPI/33552

10.1074/mcp.M112.019661

http://dx.doi.org/10.1074/mcp.M112.019661

Idioma(s)

eng

Publicador

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

BETHESDA

Relação

MOLECULAR & CELLULAR PROTEOMICS

Direitos

closedAccess

Copyright AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Palavras-Chave #COMPARATIVE GENOMIC HYBRIDIZATION #CANCER-CELLS #ANTICANCER ALKYLPHOSPHOLIPIDS #IN-VITRO #PROTEOMICS-ANALYSIS #ANTITUMOR-ACTIVITY #STATISTICAL-MODEL #MULTIPLE-MYELOMA #DUAL INHIBITION #PATHWAY #BIOCHEMICAL RESEARCH METHODS
Tipo

article

original article

publishedVersion