Hepatocellular carcinoma (HCC) is one of the most frequently occurring cancers of the liver and accounts for approximately 500,000 deaths every year worldwide. Cyclin 01 is a key cyclin that drives hepatocyte cell cycle progression, and overexpression is often associated with uncontrolled hepatocyte proliferation leading to the development of cancerous nodules, characteristic of HCC.

In recent years, small interfering RNA (siRNA)-mediated gene silencing is beginning to show substantial promise as a new treatment modality for multiple cancers and liposome nanoparticles have emerged as the vehicles of choice for targeted drug delivery of siRNA. However, the effective therapeutic use of siRNAs critically depends on the efficient packaging and enrichment of biologically active, gene-specific siRNA molecules into Iiposome nanoparticles. Moreover, it is important to enhance the specificity and efficiency of siRNA delivery to tumor tissue, by appropriately 'flagging' the liposome surface with molecular tags which discretely recognize the target tumors, in order to minimize the non-specific toxic effects.

The goal of this proposal is to apply nanotechnology to develop effective therapeutics in the management of hepatocellular carcinoma. Specific Aim 1. To develop asymmetric liposome nanoparticles to enhance the packaging efficiency of siRNAs. siRNAs, targeting cyclin D1, will be packaged into asymmetric Iiposomes. Anionic liposomes have low packaging efficiency because siRNAs are negatively charged. Cationic Iiposomes have low delivery efficiency because of their electrostatic interactions with other cells and biomolecules along the delivery path. Asymmetric liposomes with cationic lipids on the inner layer and neutral lipids on the outer layer can achieve high packaging and delivery efficiency simultaneously. Specific Aim 2. To develop asymmetric liposome nanoparticles 'flagged' to target tumor cells. Overexpression of Glypican 3 at the cell surface is a characteristic feature of HCC. Taking advantage of the specificity antigen-antibody interaction at the tumor cell surface, liposomal surface will be flagged with anti-Glypican 3 antibodies to facilitate tumor cell-targeted delivery of siRNA. Specific Aim 3. To characterize the efficacy of targeted delivery of siRNA packaged into asymmetric liposome nanoparticles. The efficacy of siRNA delivery and function will be tested in vitro in a human hepatoma cell line (HepG2). The effects on cyclin 01 expression and cell proliferation will be compared to non-liver derived cell lines which do not express Glypican 3. The findings from these studies will set the stage for future analyses in vivo in a mouse model of hepatocellular carcinoma, which is beyond the scope of the current proposal.