Functional RNAi screen targeting cytokine and growth factor receptors reveals oncorequisite role for interleukin-2 gamma receptor in JAK3-mutation-positive leukemia

• Published in: Oncogene Vol. 34; no. 23; pp. 2991 - 2999
• Main Authors: Agarwal, A, MacKenzie, R J, Eide, C A, Davare, M A, Watanabe-Smith, K, Tognon, C E, Mongoue-Tchokote, S, Park, B, Braziel, R M, Tyner, J W, Druker, B J
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04-06-2015; Nature Publishing Group
• Subjects: 631/1647/1407/505; 631/67/1990/283; 692/420/755; Acute myeloid leukemia; Animals; Apoptosis; Binding Sites; Cell Biology; Cell Line, Tumor; Cell receptors; Cell Transformation, Neoplastic - genetics; Cytokines; Development and progression; Genetic aspects; Growth factor receptors; Growth factors; Health aspects; Human Genetics; Humans; Identification and classification; Interleukin 2; Interleukin Receptor Common gamma Subunit - antagonists & inhibitors; Interleukin Receptor Common gamma Subunit - genetics; Interleukin Receptor Common gamma Subunit - metabolism; Internal Medicine; Janus kinase; Janus Kinase 3 - genetics; Janus Kinase 3 - metabolism; Leukemia; Leukemia - genetics; Leukemia - metabolism; Leukemia - pathology; MAP kinase; Medicine; Medicine & Public Health; Mice; Molecular Sequence Data; Mutants; Mutation; Myeloid leukemia; Oncology; original-article; Pathogenesis; Phosphorylation; Properties; RNA interference; RNA, Small Interfering - pharmacology; RNA-mediated interference; Signal Transduction; Stat5 protein; Tumorigenesis
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/onc.2014.243

To understand the role of cytokine and growth factor receptor-mediated signaling in leukemia pathogenesis, we designed a functional RNA interference (RNAi) screen targeting 188 cytokine and growth factor receptors that we found highly expressed in primary leukemia specimens. Using this screen, we identified interleukin-2 gamma receptor (IL2Rγ) as a critical growth determinant for a JAK3
A572V
mutation-positive acute myeloid leukemia cell line. We observed that knockdown of IL2Rγ abrogates phosphorylation of JAK3 and downstream signaling molecules, JAK1, STAT5, MAPK and pS6 ribosomal protein. Overexpression of IL2Rγ in murine cells increased the transforming potential of activating JAK3 mutations, whereas absence of IL2Rγ completely abrogated the clonogenic potential of JAK3
A572V
, as well as the transforming potential of additional JAK3-activating mutations such as JAK3
M511I
. In addition, mutation at the IL2Rγ interaction site in the FERM domain of JAK3 (Y100C) completely abrogated JAK3-mediated leukemic transformation. Mechanistically, we found IL2Rγ contributes to constitutive JAK3 mutant signaling by increasing JAK3 expression and phosphorylation. Conversely, we found that mutant, but not wild-type JAK3, increased the expression of IL2Rγ, indicating IL2Rγ and JAK3 contribute to constitutive JAK/STAT signaling through their reciprocal regulation. Overall, we demonstrate a novel role for IL2Rγ in potentiating oncogenesis in the setting of JAK3-mutation-positive leukemia. In addition, our study highlights an RNAi-based functional assay that can be used to facilitate the identification of non-kinase cytokine and growth factor receptor targets for inhibiting leukemic cell growth.