The long-term objectives of the project are the study of isoprenoid biosynthesis in relation to cell proliferation, and the development of new approaches to cancer chemotherapy based on inhibition of the regulatory enzyme in the isoprenoid pathway, 3hydroxy3methylglutaryl coenzyme A (HMG-CoA) reductase. This enzyme catalyzes the formation of mevalonate, an essential precursor of sterols and other isoprenoids such as ubiquinone, dolichol, and newly discovered isoprenoid proteins. The activity of HMGCoA reductase is elevated in many types of tumors, and data from the preceding project period showed that an inhibitor of this enzyme, mevinolin, suppresses the growth of subcutaneous neuroblastoma in mice. Continued evaluation of mevinolin during the next project period will establish whether this compound can suppress tumor growth in rat brain tumor models such as intracerebral C-6 glioma and intracisternal Walker 256 carcinoma. Several criteria will be used to assess the efficacy of mevinolin, including survival curves and clonogenic assays of residual tumors. Histological studies of normal brain, and colonyforming assays of bone marrow cells will identify potential toxic side effects of mevinolin. The results of these studies will indicate whether phaseI clinical trials of mevinolin are warranted. Cultured neuroblastoma and LM cells will be used in basic studies to determine why blocking mevalonate synthesis leads to arrest of cell cycling. These studies will focus specifically on a novel class of proteins which are modified post- translationally with isoprenoid prosthetic groups derived from mevalonate. One of these proteins, which is localized in the nucleus, will be purified by isoelectric focusing and SDSgel electrophoresis, and a monoclonal antibody will be raised by standard mouse hybridoma technology. The antibody will then be used to determine (1) whether the highmolecular weight nuclear isoprenoid protein is related antigenically to the lowermolecular weight isoprenoid proteins found in other subcellular compartments, (2) whether suppression of mevalonate synthesis by mevinolin results in a decreased synthesis of the polypeptide portion of the isoprenoid protein,, (3) whether the synthesis of the nuclear isoprenoid protein occurs during a specific phase of the cell cycle, and (4) whether the nuclear isoprenoid protein exhibits properties of a DNAbinding protein. These studies will provide new insight into the mechanism underlying the mevalonate requirement for cell growth.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
7R01CA034569-05
Application #
3172292
Study Section
Pathology B Study Section (PTHB)
Project Start
1987-09-01
Project End
1989-12-31
Budget Start
1987-09-01
Budget End
1987-12-31
Support Year
5
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Geisinger Medical Center
Department
Type
DUNS #
City
Danville
State
PA
Country
United States
Zip Code
17822
Overmeyer, Jean H; Kaul, Aparna; Johnson, Erin E et al. (2008) Active ras triggers death in glioblastoma cells through hyperstimulation of macropinocytosis. Mol Cancer Res 6:965-77
Kaul, Aparna; Overmeyer, Jean H; Maltese, William A (2007) Activated Ras induces cytoplasmic vacuolation and non-apoptotic death in glioblastoma cells via novel effector pathways. Cell Signal 19:1034-43
Johnson, Erin E; Overmeyer, Jean H; Gunning, William T et al. (2006) Gene silencing reveals a specific function of hVps34 phosphatidylinositol 3-kinase in late versus early endosomes. J Cell Sci 119:1219-32
Ding, Jane; Soule, Gwendolyn; Overmeyer, Jean H et al. (2003) Tyrosine phosphorylation of the Rab24 GTPase in cultured mammalian cells. Biochem Biophys Res Commun 312:670-5
Maltese, William A; Soule, Gwendolyn; Gunning, William et al. (2002) Mutant Rab24 GTPase is targeted to nuclear inclusions. BMC Cell Biol 3:25
Overmeyer, J H; Wilson, A L; Maltese, W A (2001) Membrane targeting of a Rab GTPase that fails to associate with Rab escort protein (REP) or guanine nucleotide dissociation inhibitor (GDI). J Biol Chem 276:20379-86
Erdman, R A; Shellenberger, K E; Overmeyer, J H et al. (2000) Rab24 is an atypical member of the Rab GTPase family. Deficient GTPase activity, GDP dissociation inhibitor interaction, and prenylation of Rab24 expressed in cultured cells. J Biol Chem 275:3848-56
Sheridan, K M; Maltese, W A (1998) Expression of Rab3A GTPase and other synaptic proteins is induced in differentiated NT2N neurons. J Mol Neurosci 10:121-8
Wilson, A L; Erdman, R A; Castellano, F et al. (1998) Prenylation of Rab8 GTPase by type I and type II geranylgeranyl transferases. Biochem J 333 ( Pt 3):497-504
Overmeyer, J H; Wilson, A L; Erdman, R A et al. (1998) The putative ""switch 2"" domain of the Ras-related GTPase, Rab1B, plays an essential role in the interaction with Rab escort protein. Mol Biol Cell 9:223-35

Showing the most recent 10 out of 39 publications