Lipoproteins as drug delivery vehicles for cancer and tumor therapeutics

Lipoproteins are biological lipid carriers play important role in transport of fats within the body.1 These are natural nanoparticles which serve as drug-delivery vehicles due to their small size, long residence time in the circulation.2 Low-density lipoprotein (LDL) carries cholesterol in plasma3 and play important role in its metabolism in normal cells as well as in cancer cells.4 Lipoproteins carry highdrug payload and are used as delivery vehicles for transportation of chemotherapeutic agents. These bear unique targeting capabilities because of their easy transportation to cancer and tumor sites. LDL loaded with r11-DOX is used to treat cancer cells. LDL follows receptor pathway is used to deliver radionucleotides for the treatment of neoplasms and tumors.5 Both liposomes and oil emulsions are also used to carry water-insoluble photosensitizers for treatment of tumors.6 Besides, low-density lipoproteins (LDLs) monoclonal antibodies are also most promising delivery vehicles for anticancer drugs. For delivery of therapeutic agents liposomes bind to some antibody and loaded drug are internalized by into macrophages via the receptor-mediated pathway for modified LDL.7 More specifically, loaded drug is assimilated through receptor-mediated pathway in cancer cells and its rate is much higher than that of normal cells. For transport of drugs to new targets, lipoproteins are bound to ligands. Lipoproteins structure is modified to tag nucleic acids, photosensitizers for therapeutics. These also act as biophysical devices like contrast agents and can be loaded with drugs, LPs and phospholipids. These natural drug nanocarriers escape any interaction with immune cells and reticuloendothelial systems.8 Hence, drugs loaded on LDLs safely transported to tumor cells without loss of their activity.9 After receptor-mediated uptake of drug-lipoprotein complex escape enzyme attack.2 Lipoproteins are safe, biocompatible, biodegradable, nonimmunogenic and successfully carry diverse therapeutic molecules to the site of invasion. Lipoproteins: transport vehicles of lipids