This Article Full Text Full Text (PDF) Supplementary Data Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ambrogio, C. Articles by Chiarle, R. Search for Related Content PubMed PubMed Citation Articles by Ambrogio, C. Articles by Chiarle, R.

The Anaplastic Lymphoma Kinase Controls Cell Shape and Growth of Anaplastic Large Cell Lymphoma through Cdc42 Activation

¹ Center for Experimental Research and Medical Studies, ² Department of Biomedical Sciences and Human Oncology, and ³ Department of Genetics, Biology, and Biochemistry and Molecular Biotechnology Center, University of Torino, Turin, Italy; ⁴ Department of Cell Biology, Harvard Medical School, Boston, Massachusetts; and ⁵ Department of Pathology and New York Cancer Center, New York University School of Medicine, New York, New York

Requests for reprints: Roberto Chiarle, Department of Biomedical Sciences and Human Oncology, University of Torino, Via Santena 7, 10126 Turin, Italy. Phone: 39-11-633-6860; Fax: 39-11-633-6887; E-mail: roberto.chiarle{at}unito.it.

Key Words: Lymphoma • Anaplastic • ALK • Cdc42 • VAV1

Anaplastic large cell lymphoma (ALCL) is a non-Hodgkin's lymphoma that originates from T cells and frequently expresses oncogenic fusion proteins derived from chromosomal translocations or inversions of the anaplastic lymphoma kinase (ALK) gene. The proliferation and survival of ALCL cells are determined by the ALK activity. Here we show that the kinase activity of the nucleophosmin (NPM)-ALK fusion regulated the shape of ALCL cells and F-actin filament assembly in a pattern similar to T-cell receptor–stimulated cells. NPM-ALK formed a complex with the guanine exchange factor VAV1, enhancing its activation through phosphorylation. VAV1 increased Cdc42 activity, and in turn, Cdc42 regulated the shape and migration of ALCL cells. In vitro knockdown of VAV1 or Cdc42 by short hairpin RNA, as well as pharmacologic inhibition of Cdc42 activity by secramine, resulted in a cell cycle arrest and apoptosis of ALCL cells. Importantly, the concomitant inhibition of Cdc42 and NPM-ALK kinase acted synergistically to induce apoptosis of ALCL cells. Finally, Cdc42 was necessary for the growth as well as for the maintenance of already established lymphomas in vivo. Thus, our data open perspectives for new therapeutic strategies by revealing a mechanism of regulation of ALCL cell growth through Cdc42. [Cancer Res 2008;68(21):8899–907]