Responsive luminescence lanthanide bioprobes for imaging and inhibition of overexpressed proteins in cancer

The dimeric viral oncoprotein, Epstein-Barr nuclear antigen 1 (EBNA1), is known to be responsible for the development of EBV (Epstein-Barr virus)-related malignancies and the maintenance of EBV episome. Given that carcinogenesis of EBV-associated carcinoma is symbiotically connected with EBV infection and EBNA1 can function (e.g. replication, DNA binding and transactivation) only upon dimerization (formation of the active form), recent studies (including our related findings) have demonstrated that a fluorescent probe consisting of a chromophore and an EBNA1-specific molecule which hampers the dimer formation can be exploited for the imaging and inhibition of latent EBV-infected cells simultaneously. However, these studies with small organic molecules are only available in cytoplasm with limited responsive signal changes, board emissions, short lifetimes and low signal-to-noise ratios; practically unachievable also is the real- time function evaluation of EBNA1 using peptides on their own.

In this project, we would like to provide a novel strategy with lanthanide luminescence to study (image) the regulation of EBNA1 dimizerimation and interfere the growth of EBV- associated tumor cells. Long emission lifetime with time-resolved microsopy had already illustrated such advantages on improving the signal-to-noise ratio for molecular imaging. As justified by our recent publications on responsive luminescent lanthanide materials towards various biological tasks in solution/in vitro/in vivo, our research team has thorough experience in lanthanide coordination chemistry, spectroscopy, peptide chemistry, and in vitro biological applications. Therefore, we aim to develop luminescent EBNA1-specific lanthanide bio-probes with high selectivity towards EBNA1 and capability of handicapping the dimerization for in vitro imaging and inhibition of EBNA1 as anti-EBV-related carcinoma agents.

To further support our work here, we had performed a string of proof-of-concept experiments to consolidate our hypotheses: (1) several EBNA1-specific europium complexes with tailor-made synthetic peptides had been prepared which can be excited in the visible, even in near-infrared, region, to give responsive fingerprint europium emission to EBNA1; (2) strong binding and high selecticity twoward EBNA1; and (3) they are cell-permeable with different subcellular localizations for EBNA1 in vitro imaging and inhibition. This proposal will pave the way for the development of new- generation responsive lanthanide complexes conjugated with organic chromophores and EBNA1-specific peptides as dual probes with both imaging and anti-tumor properties. Making a success of this research can bring to society a more powerful tool (especially able to combine multi-photon and time-resolved technology) to unveil the mystery and understand the very roles of EBNA1 in EBV-associated carcinoma for further cancer diagnosis, therapy, and research.