Graduation Date

Spring 2022

Document Type

Thesis

Program

Master of Science degree with a major in Biology

Committee Chair Name

Amy Sprowles

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Brigitte Blackman

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Mark Wilson

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Anne Marie Barrette

Fourth Committee Member Affiliation

Community Member or Outside Professional

Subject Categories

Biology

Abstract

Asymmetric cell division and migration are critical for neural stem cell differentiation and brain development. When these processes are dysregulated in neural progenitor cells (NPCs), developmental defects and diseases like glioma can result. Lgl1 is a tumor suppressor gene that was first characterized in Drosophila neuroblasts (Strand et al., 1994). It is best known for its regulation of asymmetric cell division through its association with the Par complex. The PI3K/AKT signaling cascade is involved in cellular migration and is also regulated by Par signaling. Unpublished data from the Sprowles laboratory suggests a potential role of Lgl1 in migration and other cellular processes regulated through mTOR/AKT signaling. To investigate this further, we used targeted drugs to manipulate various components of the mTOR/AKT and PTEN/PI3K pathways in genetically matched Lgl1-/- and Lgl1+/+ P30 primary cell lines isolated from the subventricular zone (SVZ) and corpus collosum (CC) of mice to interrogate their roles in migration (spheroid migration assay). Immunocytochemistry experiments on these same cell lines revealed the loss of Lgl1 resulted in various phosphorylation changes in pAKT T308 and pAKT S473 in the two cell types, representative of both neural stem cells (SVZ) and neural progenitor cells (cultured as OPCs), suggesting the loss of Lgl1 impacts the regulation of the mTOR/AKT pathway. Additionally, our data suggested a functional association between LGL1 and to PI3K, as we found that the most dramatic differences in protrusion number were found in the drug condition linked to PI3K inhibition. Overall, loss of Lgl1 appears to result in a more cancer-like phenotype with an increase in migration and changes in localization of signaling molecules. Our findings suggest that changes in AKT phosphorylation are a key link between LGL1 and the migratory defects we observed and pointed to a model in which PI3K dysregulation resulted in migration and morphological differences between genotypes. Further studies could investigate downstream expression patterns of cell survival and proliferation markers, transcriptomics, and explore these patterns through immunohistochemistry. These findings could be applied to understanding glioblastoma progression and how loss of cell polarity molecules affects cancer properties.

Citation Style

APA

APLAC_33633.pdf (196 kB)
APLAC Protocol for Animal Use

Available for download on Saturday, April 01, 2023

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