Selective reduction of JAK2V617F-dependent cell growth by siRNA/shRNA and its reversal by cytokines.
The JAK(V617F) mutation is responsible for the majority of breakpoint cluster region (BCR)/Abelson (ABL)-negative myeloproliferative disorders. Ongoing clinical trials of Janus kinase 2 (JAK2) inhibitors in myeloproliferative disorder patients use small molecules targeting both wild-type and mutated JAK2. To selectively target malignant cells, we developed JAK2(V617F)-specific small interfering RNAs or short hairpin RNAs. Expression of these RNAs in cell lines or CD34(+) cells from patients reduced JAK2(V617F)-driven autonomous cell proliferation. Mechanisms of inhibition involved selective JAK2(V617F) protein down-regulation, and consequently, decrease in signal transducer and activator of transcription 5 phosphorylation, cell-cycle progression, and cell survival. However, the addition of high concentrations of cytokines to cell lines or erythropoietin to patient cells greatly reduced growth inhibition. Similarly, the efficacy of a JAK2 small molecule inhibitor on cell line and patient cell proliferation dose dependently decreased with the addition of cytokines. Our results demonstrate that it is possible to specifically target JAK2(V617F) by RNA interference (RNAi) strategies. In addition, cytokines partially reverse the inhibition induced by both RNAi and small molecule approaches. This strongly suggests that patient cytokine levels in current JAK2 inhibitor clinical trials modulate the outcome of these therapies.
Jedidi
Abire
A
Inserm, Unité 790, Institut Gustave Roussy, Villejuif, France.
Marty
Caroline
C
Oligo
Charleen
C
Jeanson-Leh
Laurence
L
Ribeil
Jean-Antoine
JA
Casadevall
Nicole
N
Galy
Anne
A
Vainchenker
William
W
Villeval
Jean-Luc
JL
D018952:Antigens, CD34 / Q000096:biosynthesis; D017209:Apoptosis; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D016207:Cytokines / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism*; D020014:K562 Cells; D009154:Mutation; D010766:Phosphorylation; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism*
D018952:Antigens, CD34; D016207:Cytokines; D034741:RNA, Small Interfering; C507924:JAK2 protein, human; D053614:Janus Kinase 2