This project will determine the influence of ceramide, ceramide metabolites, and glucosylceramide synthase (GCS) on expression of the multidrug-resistant phenotype, using cancer cells in vitro, and tumor xenographs in vivo, as model systems. GCS catalyzes the formation of glucosylceramide (GC), the building block of higher glycolipids (cerebrosides, gangliosides). Glycolipids such as GC are also substrates for ABC transporter proteins, of which the MDR1 protein, P-glycoprotein (P-gp) is a member. Overexpression of MDR1/P-gp in cells represents a major impediment to effective treatment of many infectious and malignant diseases. Our objective is to improve treatment of disease. If lipids are involved in expression of the MDR1 phenotype, then blocking lipid metabolism at a specific juncture may be a means of limiting multidrug resistance. Many agents - chemotherapy drugs, nitrous oxide, gamma-irradiation - promote an increase in cellular ceramide, which elicits apoptosis. However, high levels of ceramide can also trigger overexpression of GCS due to increased availability of the enzymes lipoidal substrate, leading to elevated levels of GC. Because of the relationship between chemotherapy drugs and ceramide generation, and because high levels of GC are found in multidrug-resistant cancer cells and tumors, we hypothesize that lipids enhance expression of the multidrug-resistant phenotype. This enhancement would dull cellular responses to antibiotics, antitumor agents, and HIV protease inhibitors.
The aims of this proposal are: 1. to determine the influence of GCS on MDR1/P-gp expression;2. to determine the influence of GCS modulation by PPMP, a GCS inhibitor, on MDR1/P-gp expression and response to doxorubicin in an in vitro multidrug-resistant breast tumor xenograft model;3. to determine the influence of lipids (ceramide, glycolipids) on expression of the multidrug-resistant phenotype, 4. to determine the influence of chemotherapy drugs on GCS and MDR1 expression. We have ordered the Aims to facilitate testing of proof of principle.
Aim 1 will demonstrate the power of targeting GCS as an approach to limiting MDR1 expression, using in vitro models.
Aim 2, using animal models, will evaluate the power of targeting GCS as an approach to treating drug resistance, in vivo.
Aims 3 and 4 focus on mechanisms, and their outcomes will not detract from the possible therapeutic value of the study. This is the first study to investigate the influence of lipids on the multidrug-resistant phenotype. The results could lead to improved treatment of HIV/AIDS, malignant disorders, and bacterial and parasitic infectious diseases, as treatment of these diseases is classically hindered by drug resistance.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM077391-03
Application #
7586764
Study Section
Special Emphasis Panel (ZRG1-CB-G (03))
Program Officer
Chin, Jean
Project Start
2007-02-01
Project End
2011-01-31
Budget Start
2009-02-01
Budget End
2010-01-31
Support Year
3
Fiscal Year
2009
Total Cost
$436,967
Indirect Cost
Name
John Wayne Cancer Institute
Department
Type
DUNS #
556074458
City
Santa Monica
State
CA
Country
United States
Zip Code
90404
Morad, Samy A F; Messner, Maria C; Levin, Jonathan C et al. (2013) Potential role of acid ceramidase in conversion of cytostatic to cytotoxic end-point in pancreatic cancer cells. Cancer Chemother Pharmacol 71:635-45
Morad, Samy A F; Cabot, Myles C (2013) Ceramide-orchestrated signalling in cancer cells. Nat Rev Cancer 13:51-65
Barth, Brian M; Shanmugavelandy, Sriram S; Tacelosky, Diana M et al. (2013) Gaucher's disease and cancer: a sphingolipid perspective. Crit Rev Oncog 18:221-34
Morad, Samy A F; Madigan, James P; Levin, Jonathan C et al. (2013) Tamoxifen magnifies therapeutic impact of ceramide in human colorectal cancer cells independent of p53. Biochem Pharmacol 85:1057-65
Morad, Samy A F; Levin, Jonathan C; Shanmugavelandy, Sriram S et al. (2012) Ceramide--antiestrogen nanoliposomal combinations--novel impact of hormonal therapy in hormone-insensitive breast cancer. Mol Cancer Ther 11:2352-61
Flowers, Margaret; Fabrias, Gemma; Delgado, Antonio et al. (2012) C6-ceramide and targeted inhibition of acid ceramidase induce synergistic decreases in breast cancer cell growth. Breast Cancer Res Treat 133:447-58
Gouaze-Andersson, Valerie; Flowers, Margaret; Karimi, Ramin et al. (2011) Inhibition of acid ceramidase by a 2-substituted aminoethanol amide synergistically sensitizes prostate cancer cells to N-(4-hydroxyphenyl) retinamide. Prostate 71:1064-73
Chapman, Jacqueline V; Gouazé-Andersson, Valérie; Karimi, Ramin et al. (2011) P-glycoprotein antagonists confer synergistic sensitivity to short-chain ceramide in human multidrug-resistant cancer cells. Exp Cell Res 317:1736-45
Gouaze-Andersson, Valerie; Cabot, Myles C (2011) Sphingolipid metabolism and drug resistance in hematological malignancies. Anticancer Agents Med Chem 11:891-903
Messner, Maria C; Cabot, Myles C (2011) Cytotoxic responses to N-(4-hydroxyphenyl)retinamide in human pancreatic cancer cells. Cancer Chemother Pharmacol 68:477-87

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