Glioblastoma multiforme (GBM) is a malignancy of the glial cells in the brain that is 100% fatal. Unlike normal brain tissue, GBM tumor cells exhibit abundant LDL receptors (LDLR), which suggests that the LDLR may be a unique molecular target for delivery of anti-tumor agents to GBM.
The specific aims of this project are: (1) Develop a drug-loaded synthetic low-density lipoprotein (sLDL) by utilizing a synthetic peptide attached to. a lipid microemulsion; and (2) Using GBM cell lines, determine binding, uptake, and cell-killing potential of drug-loaded synthetic LDL. The sLDL will be composed of a synthetic bifunctional peptide, which contains an LDLR binding domain and a lipid binding domain, on the surface of a lipid microemulsion of phospholipid, triglyceride, cholesteryl oleate, and a cytotoxic lipophilic prodrug, paclitaxel oleate (PO). Several initial concentrations of PO will be tested to determine the optimal concentration for incorporation into the microemulsion. Homogeneity and reproducibility of size and composition of the sLDL-PO particle will be determined. The synthetic peptide and paclitaxel oleate will be evaluated to determine that they associate stably on the microemulsion and do not exchange with other lipoproteins, such as the high-density lipoprotein particle, found in the-cerebrospinal fluid. To determine that the particles specifically bind to LDLR, uptake is time- and concentration-dependent, and sLDL-PO localize in cellular lysosomes, sLDL-PO will be tested using three GBM cell lines, SF-767, U-251, and SF-763. These tests will determine if sLDL-PO binds to LDLR and is internalized through receptor mediated endocytosis. sLDL-PO cell-killing potential will be evaluated in three GBM cell lines, using a ce-l proliferation assay to determine if sLDL-PO is more efficient at killing cells than microemulsion-PO or PO alone. This novel particle has the potential to provide a better treatment to individuals suffering from GBM tumors. Relevance: Glioblastoma multiforme (GBM) is the major primary brain tumor in adults and is extremely difficult to treat; thus, median survival time is 1 year. This proposal will develop a unique drug-containing synthetic lipoprotein particle that can target drugs to GBM via a specific receptor. This targeted delivery will be beneficial in bringing high doses of drugs to tumors cells but hot to normal cells. ? ? ?
