Since the discovery of neural stem cells, a connection between these cells and the origin of brain tumors has been theorized. The recent discovery by us and others of brain tumor stem cells and their close phenotypic relationship to neural stem cells has prompted us to explore proliferative mechanisms that are in common between neural stem cells and brain tumors. We have previously found that maternal embryonic leucine zipper kinase (MELK), a serine-threonine kinase, is a marker for and regulates the proliferation of self- renewing neural progenitors (neural stem cells) in developing mouse brain. We have also found that MELK expression correlates with brain tumor grade and survival and that it is a """"""""hub"""""""" gene, 1 whose expression predicts the expression of numerous other cell cycle genes. We hypothesize that MELK is an important regulator of brain tumor proliferation, mediates the self-renewal of brain tumor stem cells, and serves as a marker for brain tumor stem cells. However, further studies are needed to determine if MELK and its putative molecular pathway will serve as targets for brain tumor therapy. This proposal will address these issues. We will first perform experiments to determine whether MELK mediates the proliferation of brain tumor cell lines, focusing on medulloblastoma and glioblastoma multiforme (GBM). These tumors were chosen because they are common, and there is strong preliminary evidence supporting the hypothesis that MELK regulates their function. Also, since the presence of brain tumor stem cells in medulloblastoma has been questioned, it will be important to determine whether MELK functions in a different capacity in these tumors compared to GBM. We will establish the mechanisms underlying MELK effects by determining MELK's role in regulating the cell cycle, the genes that mediate its function, and whether this function is mediated by its kinase domain or the domain critical for a function in RNA processing. We will also determine whether MELK function is critical for brain tumor cell line proliferation in the in vivo environment of the brain. To determine whether MELK is expressed by cancer stem cells, we will first test whether it is expressed by sphere-forming multipotent progenitors derived from tumors and then whether these progenitors are capable of tumor initiation. We will then determine the role of MELK in brain tumor stem cells in vitro and in vivo. Through these studies, we will determine whether MELK or its functional pathway is an appropriate target for novel therapies of brain tumors. Lay summary: A study of stem cell genes will lead to promising new treatments for brain tumors. This application focuses on a gene, MELK, that is a critical regulator of the proliferation (division) of normal neural stem cells and is expressed by brain tumors. We will determine the function of MELK in brain tumor cells (glioma and medulloblastoma) and whether it is important for the proliferation of tumor-causing """"""""cancer stem cells"""""""". If MELK is important for these functions, then it becomes a target for potential treatments. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS052563-01A1
Application #
7105726
Study Section
Drug Discovery and Molecular Pharmacology Study Section (DMP)
Program Officer
Fountain, Jane W
Project Start
2006-04-27
Project End
2009-02-28
Budget Start
2006-04-27
Budget End
2007-02-28
Support Year
1
Fiscal Year
2006
Total Cost
$252,515
Indirect Cost
Name
University of California Los Angeles
Department
Pharmacology
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Laks, Dan R; Oses-Prieto, Juan A; Alvarado, Alvaro G et al. (2018) A molecular cascade modulates MAP1B and confers resistance to mTOR inhibition in human glioblastoma. Neuro Oncol 20:764-775
Garrett, Matthew; Sperry, Jantzen; Braas, Daniel et al. (2018) Metabolic characterization of isocitrate dehydrogenase (IDH) mutant and IDH wildtype gliomaspheres uncovers cell type-specific vulnerabilities. Cancer Metab 6:4
Mai, Wilson X; Gosa, Laura; Daniels, Veerle W et al. (2017) Cytoplasmic p53 couples oncogene-driven glucose metabolism to apoptosis and is a therapeutic target in glioblastoma. Nat Med 23:1342-1351
Senese, Silvia; Lo, Yu-Chen; Gholkar, Ankur A et al. (2017) Microtubins: a novel class of small synthetic microtubule targeting drugs that inhibit cancer cell proliferation. Oncotarget 8:104007-104021
Ludwig, Kirsten; Kornblum, Harley I (2017) Molecular markers in glioma. J Neurooncol 134:505-512
Laks, Dan R; Ta, Lisa; Crisman, Thomas J et al. (2016) Inhibition of Nucleotide Synthesis Targets Brain Tumor Stem Cells in a Subset of Glioblastoma. Mol Cancer Ther 15:1271-8
Shoemaker, Lorelei D; Kornblum, Harley I (2016) Neural Stem Cells (NSCs) and Proteomics. Mol Cell Proteomics 15:344-54
Laks, Dan R; Crisman, Thomas J; Shih, Michelle Y S et al. (2016) Large-scale assessment of the gliomasphere model system. Neuro Oncol 18:1367-78
Nathanson, David A; Gini, Beatrice; Mottahedeh, Jack et al. (2014) Targeted therapy resistance mediated by dynamic regulation of extrachromosomal mutant EGFR DNA. Science 343:72-6
Minata, Mutsuko; Gu, Chunyu; Joshi, Kaushal et al. (2014) Multi-kinase inhibitor C1 triggers mitotic catastrophe of glioma stem cells mainly through MELK kinase inhibition. PLoS One 9:e92546

Showing the most recent 10 out of 24 publications