title: Selective reduction of JAK2V617F-dependent cell growth by siRNA/shRNA and its reversal by cytokines.
abstract: 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.
authors: Inserm, Unité 790, Institut Gustave Roussy, Villejuif, France.
authors: Abire
authors: A
authors: Jedidi
authors: Caroline
authors: C
authors: Marty
authors: Charleen
authors: C
authors: Oligo
authors: Laurence
authors: L
authors: Jeanson-Leh
authors: Jean-Antoine
authors: JA
authors: Ribeil
authors: Nicole
authors: N
authors: Casadevall
authors: Anne
authors: A
authors: Galy
authors: William
authors: W
authors: Vainchenker
authors: Jean-Luc
authors: JL
authors: Villeval
mesh_terms: 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*
chemical_list: D018952:Antigens, CD34; D016207:Cytokines; D034741:RNA, Small Interfering; C507924:JAK2 protein, human; D053614:Janus Kinase 2