Oral Presentation Advances in Neuroblastoma Research Congress 2016

A small molecule kinome inhibitor screen identifies the TGF-beta-activated kinase 1 (TAK1) as a target for combination therapy in MYC-driven neuroblastoma (#23)

Monika Podkowa 1 , Daniel A Morgenstern 2 , Ivette Valencia-Sama 3 , Ruoshi Shi 1 , Rboin M Hallet 3 , David R Kaplan 4 , Meredith Irwin 5
  1. Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
  2. Oncology, Great Ormond Street, London, England
  3. Cell Biology Program, Hospital for Sick Children, Toronto, ON, Canada
  4. Neurosciences and Mental Health, Hospital for Sick Children, Toronto, ON, Canada
  5. Division of Hematology-Oncology, Hospital for Sick Children, Toronto, ON, Canada

MYCN amplification (MYCNA) and/or high levels of c-MYC expression predict recurrence and poor outcome for loco-regional and metastatic neuroblastoma. Although recent studies have identified novel agents, including bromodomain and aurora kinase inhibitors, which demonstrate selective activity in MYCNA neuroblastoma, there is a need to identify agents to enhance the efficacy of these drugs in MYC-expressing relapsed neuroblastoma.

We performed a high throughput screen with a unique collection of 480 kinase inhibitors to identify alterations in signaling pathways that regulate survival and differentiation of neuroblastoma. Hits were defined as compounds (2umol/L) with >75% inhibition of metabolic activity relative to control. Top hits included novel drugs and inhibitors of kinases previously implicated in neuroblastoma, including PLK1, cdks/cyclins, Chk1/wee1, aurora A/B, and PI3K/Akt/mTOR. To prioritize candidates with efficacy we compared our results with published shRNA screens. The serine threonine MAP kinase kinase kinase (MAP3K7) family protein TAK1 emerged as a potential novel regulator of neuroblastoma survival.

 Two TAK1 inhibitors (AZ-TAK1 and 5z-7-oxozeanol) demonstrated in vitro efficacy across a panel of 11 cell lines representing a range of genetic profiles (including 2 primary MYCNA lines).  For AZ-TAK1 the IC50 ranged from 0.28- >10uM. The lowest IC50 was detected in cells with MYCNA or high c-myc and sensitivity correlated with levels of induced MYCN in SHEP-tet cells. The level of phospho-TAK1 was highest in cells with low IC50 and was inhibited by treatment with AZ-TAK1. Pharmacologic inhibition or TAK1 knockdown led to apoptosis, and in certain cases differentiation. As a single agent AZ-TAK1 suppressed tumor growth in mice with neuroblastoma xenografts. In vitro combination studies also demonstrated additive and synergistic activities with other agents that suppress MYCN expression and signaling including JQ-1 and MLN8327. These results suggest TAK1 may be a relevant target for combination therapy in relapsed tumors with high MYC activity.