We and others have recently found that activating mutations in the serine/threonine kinase BRAF may be found in as many as half of all pediatric low grade astrocytomas (LGA). The overarching goals of these studies are to characterize the role of mutant BRAF in these tumors and to identify other mutations that drive the formation of both low- and high-grade pediatric astrocytomas. Specifically, we propose to:
Aim One : Use new """"""""paraffin-friendly"""""""" genomic technologies to identify oncogenic mutations in pediatric astrocytomas. The ability to interrogate formaldehyde-fixed, paraffin-embedded archival tissues expands the available sample sets of these infrequent pediatric tumors by a factor of ten or more relative to fresh frozen tumor collections. We will use these technologies on a unique set of over 1000 archival tumor samples to address two important unresolved questions in the field. Specifically, (i) what are the recurrent mutations or amplifications in pediatric astrocytomas that lack BRAF mutations? and (ii) What are the mutations that co-occur with BRAF mutations? Aim Two: Use functional approaches to identify mutations that cooperate with activated BRAF in pediatric astrocytomas. Similarto what has been found in BRAF-mutant melanoma, we anticipate that other mutations cooperate with mutated BRAF in pediatric astrocytomas. We will use both candidate and unbiased approaches to identify such mutations through the transformation of neural progenitor cells.
Aim Three : identify """"""""druggable"""""""" signal generators that function upstream and downstream of BRAF n transformed neural progenitors. In the fullness of time, small molecule inhibitors of BRAF may be used for the treatment of BRAF mutant pediatric LGAs. However, multiple protein kinases have been shown to be co-activated in high-grade adult gliomas, and this is also likely to be the case in mutant BRAF-transformed pediatric astrocytomas. In this Aim, we will conduct kinome-wide genetic screens for kinases that can substitute for activated BRAF to dysregulate the proliferation of normal neural progenitor cells. This information will help define genes that may drive pediatric astrocytomas that lack BRAF mutations as well as defining potential mechanisms of resistance to the inhibition of BRAF. All three specific aims are supported by an Innovative Neuro Pathology Core and by shared technologies and reagents from Projects Two and Three.

Public Health Relevance

Many pediatric brain tumors can be initially treated by surgery, chemotherapy and/or radiotherapy. However, the clinical side-effects ofthese treatments in growing children can be significant. Moreover, these tumors frequently recur and eventually fail to respond to standard treatment protocols. Thus, there is an urgent need for targeted therapeutics for these tumors. This project will identify and characterize promising targets that are ripe for translational studies to develop targeted therapeutics for children with pediatric brain tumors.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Program Projects (P01)
Project #
5P01CA142536-02
Application #
8376545
Study Section
Special Emphasis Panel (ZCA1-RPRB-O)
Project Start
Project End
Budget Start
2012-02-01
Budget End
2013-01-31
Support Year
2
Fiscal Year
2012
Total Cost
$376,751
Indirect Cost
$129,721
Name
Dana-Farber Cancer Institute
Department
Type
DUNS #
076580745
City
Boston
State
MA
Country
United States
Zip Code
02215
Ni, Jing; Xie, Shaozhen; Ramkissoon, Shakti H et al. (2017) Tyrosine receptor kinase B is a drug target in astrocytomas. Neuro Oncol 19:22-30
Zhang, Jing; Gao, Xueliang; Schmit, Fabienne et al. (2017) CRKL Mediates p110?-Dependent PI3K Signaling in PTEN-Deficient Cancer Cells. Cell Rep 20:549-557
Sun, Yu; Alberta, John A; Pilarz, Catherine et al. (2017) A brain-penetrant RAF dimer antagonist for the noncanonical BRAF oncoprotein of pediatric low-grade astrocytomas. Neuro Oncol 19:774-785
Zhou, Jing; Tien, An-Chi; Alberta, John A et al. (2017) A Sequentially Priming Phosphorylation Cascade Activates the Gliomagenic Transcription Factor Olig2. Cell Rep 18:3167-3177
Zhao, Xuesong; Pak, Ekaterina; Ornell, Kimberly J et al. (2017) A Transposon Screen Identifies Loss of Primary Cilia as a Mechanism of Resistance to SMO Inhibitors. Cancer Discov 7:1436-1449
Ilic, Nina; Birsoy, K?vanç; Aguirre, Andrew J et al. (2017) PIK3CA mutant tumors depend on oxoglutarate dehydrogenase. Proc Natl Acad Sci U S A 114:E3434-E3443
Pak, Ekaterina; Segal, Rosalind A (2016) Hedgehog Signal Transduction: Key Players, Oncogenic Drivers, and Cancer Therapy. Dev Cell 38:333-44
Stevens, Mark M; Maire, Cecile L; Chou, Nigel et al. (2016) Drug sensitivity of single cancer cells is predicted by changes in mass accumulation rate. Nat Biotechnol 34:1161-1167
Ni, Jing; Ramkissoon, Shakti H; Xie, Shaozhen et al. (2016) Combination inhibition of PI3K and mTORC1 yields durable remissions in mice bearing orthotopic patient-derived xenografts of HER2-positive breast cancer brain metastases. Nat Med 22:723-6
Edwards, Amanda L; Meijer, Dimphna H; Guerra, Rachel M et al. (2016) Challenges in Targeting a Basic Helix-Loop-Helix Transcription Factor with Hydrocarbon-Stapled Peptides. ACS Chem Biol 11:3146-3153

Showing the most recent 10 out of 57 publications