Development of Target-Specific Gold Nanoclusters for Assessment of Cancer Progression and Inhibition of Cancer Cell Proliferation

The glucose metabolic rate in cancer cells is a crucial piece of information for the cancer progression. In this proposal, a feasible method to monitor processes of oncogenic mutations will be developed and demonstrated. The fluorescent gold nanoclusters conjugated with glucose (glucose-AuNCs) will be synthesized as a cancer-targeting probe for glucose transporters (Gluts) overexpressed U-87 MG cancer cells, which can be observed under confocal microscopy. The structural and optical characterizations of fluorescent glucose-AuNCs will be confirmed by transmission electron microscope (TEM), inductively coupled plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS) and matrix-assisted laser desorption ionization-time of flight mass (MALDI-TOF-MS). The MTT assay will be executed to examine the biocompatibility of water-soluble glucose-AuNCs before further biomedical applications. To demonstrate the target-specific ability of glucose-AuNCs, the Gluts overexpressed human malignant glioma cell line (U-87 MG) and normal human fetal glial cell line (SVG p12) will be used to investigate the target-specific fluorescence imaging by using AuNCs and glucose-AuNCs as fluorescent contrast agents. The glucose metabolic cleavage of glucose-AuNCs by glycolytic enzymes from U-87 MG cancer cell will be measured by fluorescence change of glucose-AuNCs. The fluorescence change based on the integrated area under fluorescence spectra (At) of glucose-AuNCs will be plotted as a function of different reaction time (t) with glycolytic enzymes. The fitted curve of At versus t will be simulated to explain the kinetics of glucose metabolic cleavage rate of glucose-AuNCs by glycolytic enzymes. The rate constant k could be utilized to determine the glucose metabolic rate of glucose-AuNCs for the quantitative analysis of cancer progression. Furthermore, the unique fluorescent probes of gold nanoclusters conjugated with 2A3 (2A3-AuNCs) will be developed for assessment of cancer progression and inhibition of cancer cell proliferation. We plan to use one-pot hydrothermal synthesis with our homemade 2A3 antibody to prepare 2A3-AuNCs. After preparation of 2A3-AuNCs, we will apply target-specific 2A3-AuNCs as fluorescent probes to target CEACAM6 overexpressed pancreatic cancer. After binding with CEACAM6, the fluorescence changes of 2A3-AuNCs will be measured and calculated to simulate their kinetics for assessment of pancreatic cancer progression by time-lapse confocal fluorescence microscopy. The 2A3 antibody has also shown the ability to inhibit cancer cell proliferation. Therefore, the fluorescence imaging and fluorescence change of 2A3-AuNCs will be applied to study their possibility for inhibition of pancreatic cancer cell proliferation. Eventually, we hope that we will be able to develop a practical application of target-specific AuNCs as a fluorescent probe for assessment of cancer progression and inhibition of cancer cell proliferation.