Skip to Content
Merck
  • Distinct Acute Lymphoblastic Leukemia (ALL)-associated Janus Kinase 3 (JAK3) Mutants Exhibit Different Cytokine-Receptor Requirements and JAK Inhibitor Specificities.

Distinct Acute Lymphoblastic Leukemia (ALL)-associated Janus Kinase 3 (JAK3) Mutants Exhibit Different Cytokine-Receptor Requirements and JAK Inhibitor Specificities.

The Journal of biological chemistry (2015-10-09)
Elisabeth Losdyck, Tekla Hornakova, Lorraine Springuel, Sandrine Degryse, Olga Gielen, Jan Cools, Stefan N Constantinescu, Elisabetta Flex, Marco Tartaglia, Jean-Christophe Renauld, Laurent Knoops
ABSTRACT

JAK1 and JAK3 are recurrently mutated in acute lymphoblastic leukemia. These tyrosine kinases associate with heterodimeric cytokine receptors such as IL-7 receptor or IL-9 receptor, in which JAK1 is appended to the specific chain, and JAK3 is appended to the common gamma chain. Here, we studied the role of these receptor complexes in mediating the oncogenic activity of JAK3 mutants. Although JAK3(V674A) and the majority of other JAK3 mutants needed to bind to a functional cytokine receptor complex to constitutively activate STAT5, JAK3(L857P) was unexpectedly found to not depend on such receptor complexes for its activity, which was induced without receptor or JAK1 co-expression. Introducing a mutation in the FERM domain that abolished JAK-receptor interaction did not affect JAK3(L857P) activity, whereas it inhibited the other receptor-dependent mutants. The same cytokine receptor independence as for JAK3(L857P) was observed for homologous Leu(857) mutations of JAK1 and JAK2 and for JAK3(L875H). This different cytokine receptor requirement correlated with different functional properties in vivo and with distinct sensitivity to JAK inhibitors. Transduction of murine hematopoietic cells with JAK3(V674A) led homogenously to lymphoblastic leukemias in BALB/c mice. In contrast, transduction with JAK3(L857P) induced various types of lymphoid and myeloid leukemias. Moreover, ruxolitinib, which preferentially blocks JAK1 and JAK2, abolished the proliferation of cells transformed by the receptor-dependent JAK3(V674A), yet proved much less potent on cells expressing JAK3(L857P). These particular cells were, in contrast, more sensitive to JAK3-specific inhibitors. Altogether, our results showed that different JAK3 mutations induce constitutive activation through distinct mechanisms, pointing to specific therapeutic perspectives.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Monoclonal Anti-β-Actin antibody produced in mouse, clone AC-15, ascites fluid
Sigma-Aldrich
MISSION® esiRNA, targeting mouse Thbd
Sigma-Aldrich
MISSION® esiRNA, targeting human THBD
Sigma-Aldrich
MISSION® esiRNA, targeting human JAK1
Sigma-Aldrich
MISSION® esiRNA, targeting mouse Jak1
Sigma-Aldrich
MISSION® esiRNA, targeting mouse Mcl1
Sigma-Aldrich
MISSION® esiRNA, targeting human MCL1