Principle Investigator:
Chuck Stiles Ph.D., Dana-Farber/Brigham & Women’s Cancer Center
Goals and Objectives:
A broad body of work shows that meningiomas do not exhibit the gross chromosome instability that characterizes malignant astrocytomas in adults. Meningiomas are generally wild type for the tumor suppressor genes most commonly mutated in adult Central Nervous System cancers – P53, RB and PTEN. The hypothesis of this project is that the unregulated growth of meningioma reflects a gain-of-function mutation within a single protein kinase (or a small number of protein kinases). Recent insights into the genetics of several other solid tumors suggest that this hypothesis is reasonable.Completion of the human genome project (with concomitant drastic reductions in the cost of high throughput DNA sequencing) makes the hypothesis testable.
Accordingly, this project is to conduct a genome-wide screen for mutations in each of the ~500 protein kinases encoded in the human genome. To complete this screen a tripartite consortium was assembled in 1) Neurosurgery, 2) Molecular genetics/Bioinformatics and 3) Signal Transduction/Drug Discovery.
This project has two specific aims:
- Aim 1 is to isolate DNA of suitable quality for mutation analysis from at least 5 meningiomas. Also needed is matched normal DNA as a control for sequence polymorphisms.
- Aim 2 is to sequence roughly 5,000 exons, covering the entirety of all 90 tyrosine kinases as well as the key portions of all serine/threonine kinases and type 1 PI3 kinases.
These mutations are selected because activated protein kinases are “drugable” targets for chemotherapy. A number of protein kinase inhibitors have been developed and are already in clinical use as for the targeted therapy of other cancers. Examples include Gleevec (for chronic myelogenous leukemia), Iressa (for lung cancer) and herceptin (for breast cancer).
If Dr. Stiles and his team get a “hit” from sequence analysis, we will have no trouble getting a grant from NIH to develop this finding. Likewise, until/unless they are able to detect an activating mutation, there is no chance of NIH funding.
Project Summary and Update as of 9/30/05:
- Ten grade I meningiomas were collected and validated by pathology. Results (Inflammatory features): 1/10 moderate; 4/10 focal, 2/10 none detected; 1/10 unknown
- DNA was extracted and evaluated for quality.
- Six samples were chosen for further analysis based on quality of DNA and on availability of matching blood samples. These samples were sent to the kinome sequencing consortium at DFCI.
- Before sequencing to identify activating point mutations (an expensive and tedious process, the six samples were assessed for the presence of grosser genetic changes such as deletions or amplifications of major chromosome fragments. This was done by a method known as SNP analysis.)
- The SNP analysis showed no gross changes in the DNA of three of the six meningioma samples. These three samples have been excluded from the final sequence analysis. Samples that have no detectable amplifications or deletions in their DNA are precluded because these gross changes insure that their original samples include plenty of tumor tissue in addition to normal surround tissue. If the team does not see deletions or amplifications in the DNA, they worry that the tissue samples are dominated by normal surround tissue.
- Currently, the group is working on gathering additional tumor samples that will pass quality control for sequence analysis. They want to accrue at least six samples and hopefully more.
Project History:
Start Date: October 2004
End Date: September 2006 (project may be extended based on findings)
BSF Funding to Date: $125,000
BSF Current Fiscal Year Funding: Money from previous award is still being spent
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