Development of multi-functional biomaterials for cancer diagnosis and therapy

Abstract

Cancer is one of the leading causes of death worldwide despite great efforts to find new cures. Accurate diagnosis of cancer and therapy are both crucial in treating cancer. Various nanomaterials have been developed for diagnosis and therapy due to several advantages, such as high loading of cargo, increased retention time in vivo due to larger sizes, enhanced permeability and retention effects and feasibility of conjugating various functional moieties. Even so, limitations also exist as nanomaterials are mostly made of non-biodegradable inorganic material, and hence are not biocompatible. To overcome the shortcomings of nanomaterials, we have developed multi-functional biomaterials for cancer diagnosis and therapy.

In chapter 1, we focused on the development of a DNA probe set capable of comprehensive detection of exon 19 deletion mutation in non-small cell lung cancer. The DNA probe set, consisting of a molecular beacon and an oligo-quencher, was able to detect various deletion mutation types with high sensitivity. By detecting mutations in real-time PCR with extracted genomic DNA and in situ fluorescence imaging of cancer cells, diagnosis of exon 19 deletion mutation in non-small cell lung cancer was achieved.

In chapter 2, we developed a simple genetically encoded protein particle that targets cells in response to tumor microenvironment pH 6.5. The protein particle was produced by fusing a fluorescent mCherry protein and a fusogenic GALA peptide to the N and C-term, respectively, of a self-assembling ferritin core protein. pH sensitive cell targeting was verified with fluorescence activated cell sorting (FACS) and confocal cell imaging of various cancer cell lines. Furthermore, by fusing a translocation domain (TDP) of Pseudomonas aeruginosa exotoxin, mCherry proteins were delivered specifically to cells in response to the acidic pH 6.5.

In chapter 3, we developed a method to construct supramolecular protein assemblies using protein-ligand interactions in a programmable manner. The assemblies were constructed through a sequential growth from SpyCatcher/Tag and SnoopCatcher/Tag pair monomers. From just small monomeric proteins, assemblies as large as viruses were produced. Using fluorescent and therapeutic proteins as cargo, along with cell receptor binding domain and TDP domain, cell specific intracellular protein delivery was achieved. Cargos attached to the protein assembly showed enhanced cellular binding and thus increased therapeutic effects when compared to the monomeric forms.

In conclusion, we demonstrated the utility and potential of biomolecular nanostructures as biocompatible materials with high functionality for cancer diagnosis and therapy.