Discipline: Biological Sciences
Subcategory: Cancer Research
Philomena Nwanze - North Carolina Central University
Co-Author(s): Jennifer K. Ocasio, Caroline Glezil, and Timothy R. Gershon, University of North Carolina at Chapel Hill, NC
Medulloblastoma is the most common malignant pediatric brain tumor and results from a disorder of normal brain development. Though there is an intensive three-step treatment, 20% of children still die from the tumor. The 80% who do survive suffer from cognitive impairment and lower quality of life emphasizing the need to develop targeted and less toxic treatments. In this project we focused on two models, one that completely lacks GSK-3 (GSK deletion/DKO) and one that has a mutated beta-catenin (β-ctnn) receptor allowing it to be constitutively active (β-ctnn activation). Knowing that cortical progenitors proliferate and differentiate in response to WNT signaling, we hypothesized that GSK-3 and β-ctnn in the WNT signaling pathway play a role in regulating the Shh pathway and that there is a molecular difference between GSK-3 deletion and β-Ctnn activation models. We conducted microarray analysis in mice and found that genes such as AXIN2, WIF1, and LEF1 were differentially regulated by GSK-3 and β-Ctnn. Using embedded sections for immunohistochemistry (IHC) and cerebellar tissue samples for Western Blot (WB), we were able to validate that WIF1 is up-regulated in both genotype mice that contain constitutively active β-ctnn and GSK deletion/DKO genotypes, while LEF1 is up-regulated in mice with GSK-3 deletion. Overall, our findings suggest that cerebellar hypoplasia differences between the two models may be due to differential gene expression in the WNT signaling pathway. From these results we can further investigate WIF1 and LEF1 and test for their effectiveness in targeted therapies for Medulloblastoma.
Funder Acknowledgement(s): NCCU-LCCC Partnership grant U54 CA156735 from NCI/NIH.
Faculty Advisor: Tim Gershon, firstname.lastname@example.org
Role: I analyzed microarray data from mice using R and excel to find genes that are differentially regulated by GSK-3 and β-Ctnn. I also used embedded sections for immunohistochemistry (IHC) and cerebellar tissue samples for Western Blot (WB), to validate if WIF1 is up-regulated in both genotype mice that contain constitutively active β-ctnn and GSK deletion/DKO genotypes, and if LEF1 is up-regulated in mice with GSK-3 deletion.