Ectopic expression of the proto-oncogene Mer in pediatric T-cell acute lymphoblastic leukemia.

Published

Journal Article

The Mer receptor tyrosine kinase, cloned from a B-lymphoblastoid library, is the mammalian orthologue of the chicken retroviral oncogene v-eyk and sends antiapoptotic and transforming signals when activated. To determine if Mer expression is ectopic in T-cell acute lymphoblastic leukemia (ALL) and potentially important in leukemogenesis, we analyzed Mer expression in normal human thymocytes and lymphocytes and in pediatric ALL patient samples.Reverse transcription-PCR, flow cytometry, and immunohistochemistry were used to determine expression of Mer in sorted human thymocyte populations, lymphocytes, and lymphocytes activated by phytohemagglutinin or phorbol 12-myristate 13-acetate/ionophore. Mer expression in 34 T-cell ALL (T-ALL) patient samples was evaluated by reverse transcription-PCR, and Mer protein expression in a separate cohort of 16 patient samples was assayed by flow cytometry and Western blot.Mer expression was absent in normal thymocytes or lymphocytes, and in T cells activated with phytohemagglutinin or phorbol 12-myristate 13-acetate/ionophore. In contrast, Jurkat cells and T-ALL patient samples expressed unique 180 to 185 kDa Mer protein glycoforms. Substantial Mer RNA levels were principally observed in a subset of T-ALL patient samples that expressed B220 (P = 0.004) but lacked surface expression of CD3 (P = 0.02) and CD4 (P = 0.006), a phenotypic profile consistent with immature lymphoblasts. In addition, 8 of 16 T-ALL patient samples had Mer protein detected by flow cytometry and Western blot.Transforming Mer signals may contribute to T-cell leukemogenesis, and abnormal Mer expression may be a novel therapeutic target in pediatric ALL therapy.

Full Text

Duke Authors

Cited Authors

  • Graham, DK; Salzberg, DB; Kurtzberg, J; Sather, S; Matsushima, GK; Keating, AK; Liang, X; Lovell, MA; Williams, SA; Dawson, TL; Schell, MJ; Anwar, AA; Snodgrass, HR; Earp, HS

Published Date

  • May 2006

Published In

Volume / Issue

  • 12 / 9

Start / End Page

  • 2662 - 2669

PubMed ID

  • 16675557

Pubmed Central ID

  • 16675557

International Standard Serial Number (ISSN)

  • 1078-0432

Digital Object Identifier (DOI)

  • 10.1158/1078-0432.ccr-05-2208

Language

  • eng