Expression of sialidase Neu2 in leukemic K562 cells induces apoptosis by impairing Bcr-Abl/Src kinases signaling

Cristina Tringali, Barbara Lupo, Luigi Anastasia, Nadia Papini, Eugenio Monti, Roberto Bresciani, Guido Tettamanti, Bruno Venerando

Research output: Contribution to journalArticlepeer-review

Abstract

Chronic myeloid leukemia is a hematopoietic stem cell cancer, originated by the perpetually "switched on" activity of the tyrosine kinase Bcr-Abl, leading to uncontrolled proliferation and insensitivity to apoptotic stimuli. The genetic phenotype of myeloid leukemic K562 cells includes the suppression of cytosolic sialidase Neu2. Neu2 transfection in K562 cells induced a marked decrease (-30% and -80%) of the mRNA of the antiapoptotic factors Bcl-XL and Bcl-2, respectively, and an almost total disappearance of Bcl-2 protein. In addition, gene expression and activity of Bcr-Abl underwent a 35% diminution, together with a marked decrease of Bcr-Abl-dependent Src and Lyn kinase activity. Thus, the antiapoptotic axis Bcr-Abl, Src, and Lyn, which stimulates the formation of Bcl-XL and Bcl-2, was remarkably weakened. The ultimate consequences of these modifications were an increased susceptibility to apoptosis of K562 cells and a marked reduction of their proliferation rate. The molecular link between Neu2 activity and Bcr-Abl signaling pathway may rely on the desialylation of some cytosolic glycoproteins. In fact, three cytosolic glycoproteins, in the range 45-66 kDa, showed a 50-70% decrease of their sialic acid content upon Neu2 expression, supporting their possible role as modulators of the Bcr-Abl complex.

Original languageEnglish
Pages (from-to)14364-14372
Number of pages9
JournalJournal of Biological Chemistry
Volume282
Issue number19
DOIs
Publication statusPublished - May 11 2007

ASJC Scopus subject areas

  • Biochemistry

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