Fusogenic Liposome for Bladder Tumor Therapy

Andres M Gonzalez Bonet, Purdue University

Abstract

Bladder cancer is the fourth most common cancer in men and eleventh most common in women in the US. Because of its high recurrence rate and long progression interval, improved treatment options are needed. To enable mechanistic and therapeutic aims of Fibronectin Attachment Protein (FAP) binding, novel tris-nitrilotriacetic acid (NTA)-Alexa probes and NTA-PEG-lipids were prepared and tested for their ability to promote bladder cell internalization of His-tagged FAP. Experiments with these unique chemical probes have established the therapeutic potential of FAP as targeting ligand for bladder tumor treatment. Drug delivery systems that can specifically target bladder tumor cells have been designed for the delivery of therapeutic cargo in a programmed manner upon internalization into low pH endosomal compartments. Bladder tumor targeting and internalization requires the integration of many molecular design aspects: drug formulation and packaging, fabrication of nanoparticles with a discrete size, efficient targeting, controllable release and addressing the biological features that are characteristic of bladder tumor cells. Fluorescence microscopy and knockdown experiments, against clathrin or caveolin-1, have shown that FAP is internalized via a clathrin-independent, caveolae-dependent mechanism. This important mechanistic information places a stringent size cutoff of 70 nm for the development of a successful FAP-targeted therapy that is designed to direct the drug or gene carrier system to the caveolar compartment. In addition, the carrier must aid the micro-aggregation of FAP-FBN-Integrin receptor complex to induce internalization. Based on previous findings, our design involves the production of small unilamellar vesicles (SUV, <70 nm in>size) for the proper targeting of the caveolae-mediated endosomal uptake pathway. NTA-PEG-lipids with a high affinity toward His-tagged FAPs have been synthesized for the targeting of bladder tumor cells. The distance between each NTA was calculated to mimic the distance between two antigen binding domains of antibodies that were initially used to crosslink polyclonal anti-FAP antibodies to induce bladder tumor cell uptake. Micro-aggregation of FAP-FBN-Integrin receptor complexes has also been shown to induce the accelerated uptake of these SUV drug carrier. We have developed a novel non-viral system for drug and gene delivery that is safe, efficient and easily processed into targeted nanoparticle formulations. This was achieved by creating a new family of mosquito-borne fusion peptide-based fusogens that promote lipid-mediated membrane fusion, thereby capable of enhancing the bioavailability of the encapsulated cargo when activated within the acidic endosomal environment of target tissues. By using theory, synthetic chemistry, membrane biophysics, and cell biology we have discovered new fusogens that rationally control membrane fusion processes.

Degree

Ph.D.

Advisors

Thompson, Purdue University.

Subject Area

Chemistry

COinS