Date Completed: 3/25/09
Faculty Name: Corinne E. Griguer, Ph.D.
UAB Department: Surgery (Neurosurgery)
UAB School: Medicine
Campus Address: 1032 THT
Campus Zip: 0006
Telephone: 934-7227
Email Address: cgriguer@uab.edu
Office Fax: 975-7667
Research Progr/am Area: Neuro-Oncology
Project Title: Bioenergetics and Intrinsic Chemoresistance in Malignant Gliomas
Project Status: Already up-and-running
Proposed Start Date: April 13
Proposed End Date: August 28
Number of Weeks of Internship: 16
Number of Interns: 1
Other faculty, staff, or graduate students who may help supervise intern: G. Yancey Gillespie, Ph.D.
Expected Number of Work Hours Per Week: 37.5 hours
Expected Work Schedule for Intern: Flexible, intern can largely set his or her own schedule
Number of hours that preceptor will personally supervise or work with intern: 40
Category of Research: Laboratory Research
Cancer Research: Brain
Project Description: Glioblastoma multiforme (GBM) is the most lethal primary brain tumor with a median survival of 12-15 months. The combined approach of surgery, radiation and chemotherapy achieves substantial tumor cyto-reduction, but resistance and relapse remain as the primary causes of poorly effective regimes. Drug export at the tumor cell level is thought to be involved in intrinsic chemo-resistance of brain tumors. Simultaneous resistance of malignant cells to several anti-neoplastic agents that are structurally and functionally unrelated is known as multi-drug resistance (MDR) [1]. Malfunctions of mitochondria have been associated with development of many diseases including cancer [2-4]. However, any causal relation between mitochondrial dysfunction and development of MDR in brain tumors is unclear and will be studied here. Arguments in favor of the concept that mitochondrial dysfunction promotes expression of the MDR in gliomas are as follows: (i) high frequencies of mitochondrial DNA (mtDNA) alterations in glioma [5]; (ii) mtDNA-depleted cancer cells exhibit increased tumorigenicity [6-8]; (iii), MDR is a major cause of glioma chemotherapy failure [1]; (iv) depletion of mtDNA induces resistance to chemotherapy [9, 10]; and, (v) treatment with DNA-intercalating agents preferentially damage mtDNA [11].
This laboratory has made several key observations that provide the basis for further investigation: (1) mtDNA depleted (?0) glioma cells display increased tumorigenicity [8]; (2) ?0 cells are resistant to temozolomide (TMZ) [unpublished]; (3) Affymetrix analyses showed significant increases of transcripts coding for Major Vault Protein (MVP) in ?0 cells [unpublished]; (4) MVP protein expression is also up-regulated in ?0 cells [unpublished]; (5) Treatment of glioma cells with TMZ leads to a decrease in mitochondrial membrane potential and up-regulation of MVP [unpublished]; (6) TMZ-resistant glioma cells showed decreased mitochondrial function and increased MVP expression [unpublished].
The ?0 glioma model will be studied to determine how chemo-resistance develops in glioma cells. It represents loss-of-function of oxidation phosphorylation (OxPhos) so we can test intrinsic chemo-resistance. We believe that, in this model of intrinsic chemo-resistance, mitochondrial dysfunction plays a central role.
This research project will determine whether mtDNA depletion decreases cytotoxicity of DNA intercalating agents and increases expression of MDR-associated proteins. To determine whether mitochondrial dysfunction results in increased MDR response, 3 different studies will be performed: compare the relative sensitivities of 3 different human glioma cells (U251MG, U105MG, D54MG) and their isogenic derivatives, ?0 cells (mtDNA depleted) to the cytotoxic effects of TMZ and carmustine (BCNU); measure the effects on cell growth, survival, clonogenicity, apoptosis and cell cycle distribution; quantify the extent and patterns of expression of major MDR proteins involved in chemo-resistance in glioma [1], including p-glycoprotein (MDR1), Major Resistant Protein (MRP), Breast Cancer Resistant Protein (BCRP) and MVP. Trans-mitochondrial cybrids of the ?0 cell lines (mitochondrial function is restored to parental levels) will be used as "repaired" isogenic controls.
Intern's Anticipated Duties:
Duty 1: Conducting cytotoxicity assays in vitro with different glioma cell lines under different experimental conditions
Duty 2: Detecting changes in expression of selected proteins by glioma cells under different glioma conditions
Duty 3: Using siRNA methods to determine the role of specific proteins in development of chemoresistance of malignant glioma cells
Preceptor will provide intern with access to the following: office or desk space, computer and printer, laboratory work bench space, equipment needed to complete the project, supplies needed to complete the project
Likelihood of authoring publications: Very Likely
Background, education, experience, or expertise preferred: Cell Biology; Molecular Biology; Neurosciences; Pharmacology
This faculty member has been a CaRES Preceptor for two summers.
Intern 1: Trey McClugage