19:10 - 21:00
Room: Ishikawa Ongakudō Interchange Hall
Poster Session
Targeting the IL-7R pathway in leukemia
Scott Durum1, Julie Hixon1, Emilee Senkevitch1, Sarah Cramer1, Joao Barata2, Scott Walsh1, Wenqing Li1
1National Cancer Institute, National Instiutes of Health, Frederick MD, United States, 2University of Lisbon, Lisbon, Portugal

Acute lymphoblastic leukemia, derived from immature T or B cells, is the most common cancer in children. Current chemotherapeutic regimen are effective in over 80% of T-ALL, but the failure rate and the harshness of current treatments makes new approaches desirable. We and others have recently identified gain-of-function mutations in IL-7R alpha which serve as driver oncogenes in T cell acute lymphoblastic leukemia (T-ALL) cooperating with Ras pathway mutations. Most of the IL-7R alpha mutations contain cysteine insertions that create homodimers. These signal independently of IL-7 or the gamma-c chain of the IL-7 receptor, constitutively activating Jak1. Two approaches have been undertaken to target the IL-7R pathway in T-ALL: inhibition of Jak1, and development of monoclonal antibodies (MAbs) against IL-7R alpha. Ruxolitinib is a recently FDA approved inhibitor of Jak1, and we show it is an effective inhibitor of cells driven by mutant IL-7Ralpha in vitro and in immunodeficient mice and its effect is augmented by venetoclax, a Bcl-2 inhibitor. Two novel mouse MAbs were developed that are directed against two different epitopes on human IL-7Ralpha, and they recognize both mutant and WT proteins. MAbs were chimerized with human IgG1 to optimize antibody-dependent cell mediated cytotoxicity (ADCC). These MAbs were highly effective in ADCC assays, mediating NK cell killing of T-ALL cells harboring mutant IL-7R alpha, and in xenografts of patient T-ALL cells with mutant or WT IL-7R. These approaches are being developed as new therapeutics for acute lymphoblastic leukemia, most of which use the IL-7R pathway either through normal ligand signaling or mutations in the pathway.


Reference:
Tu-P14-14
Session:
Poster Session 14 “Cytokines in cancer development and antitumor immune therapy”
Presenter/s:
Scott Durum
Presentation type:
Poster Presentation
Room:
Ishikawa Ongakudō Interchange Hall
Date:
Tuesday, 31 October 2017
Time:
19:10 - 21:00
Session times:
19:10 - 21:00