Yanbin Cai

Nuclear delivery and accumulation are very important for many anticancer drugs that interact with DNA or its associated enzymes in the nucleus. However, it is very difficult for neutrally and negatively charged anticancer drugs such as 10-hydroxycamptothecine (HCPT). Here we report a simple strategy to construct supramolecular nanomedicines for nuclear delivery of dual synergistic anticancer drugs. Our strategy utilizes the coassembly of a negatively charged HCPT-peptide amphiphile and the positively charged cisplatin. The resulting nanomaterials behave as the "Trojan Horse" that transported soldiers (anticancer drugs) across the walls of the castle (cell and nucleus membranes). Therefore, they show improved inhibition capacity to cancer cells including the drug resistant cancer cell and promote the synergistic tumor suppression property in vivo. We envision that our strategy of constructing nanomaterials by metal chelation would offer new opportunities to develop nanomedicines for combination chemotherapy.

We herein describe the tandem molecular self-assembly of a peptide derivative (1) that is controlled by a combination of enzymatic and chemical reactions. In phosphate-buffered saline (PBS), compound 1 self-assembles first into nanoparticles by phosphatase and then into nanofibers by glutathione. Liver cancer cells exhibit higher concentrations of both phosphatase and GSH than normal cells. Therefore, the tandem self-assembly of 1 also occurs in the liver cancer cell lines HepG2 and QGY7703; compound 1 first forms nanoparticles around the cells and then forms nanofibers inside the cells. Owing to this self-assembly mechanism, compound 1 exhibits large ratios for cellular uptake and inhibition of cell viability between liver cancer cells and normal liver cells. We envision that using both extracellular and intracellular reactions to trigger tandem molecular self-assembly could lead to the development of supramolecular nanomaterials with improved performance in cancer diagnostics and therapy.

It is challenging to construct high-performing excimer-based luminescent analytic tools at low molecular concentrations. We report that enzyme-instructed self-assembly (EISA) enables the monomer-excimer transition of a coumarin dye (Cou) at low molecular concentrations, and the resulting higher ordered luminescent supramolecular assemblies (i.e., nanofibers) efficiently record the spatiotemporal details of alkaline phosphatase (ALP) activity in vitro and in vivo. Cou was conjugated to short self-assembly peptides with a hydrophilic ALP-responsive group. By ALP triggering, EISA actuated a nanoparticles-nanofibers transition at low peptide concentrations followed by monomer-excimer transition of Cou. Analysis of structure-property relationships revealed that the self-assembly motif was a prerequisite for peptides to induce the monomer-excimer transition of Cou. Luminescent supramolecular nanofibers of pYD (LSN-pYD) illuminated the intercellular bridge of cancer cells and distinguished cancer cells (tissues) from normal cells (tissues) efficiently and rapidly, promising potential use for the early diagnosis of cancer. This work extends the functions of EISA and provides a new application of supramolecular chemistry.

Curcumin (Cur), a phenolic anti-oxidant compound obtained from Curcuma longa plant, possesses a variety of therapeutic properties. However, it is suffered from its low water solubility and low bioavailability property, which seriously restricts its clinical application. In this study, we developed a glycyrrhetinic acid (GA) modified curcumin supramolecular pro-gelator (GA-Cur) and a control compound Nap-Cur by replacing GA with the naphthylacetic acid (Nap). Both compounds showed good water solubility and could form supramolecular gels by disulfide bond reduction triggered by glutathione (GSH) in vitro. Both formed gels could sustainedly release Cur in buffer solutions. We also investigated the cytotoxicity of pro-gelators to HepG2 cells by a MTT assay and determined the cellular uptake behaviours of them by fluorescence microscopy and LC-MS. Due to the over expression of GA receptor in liver cancer cells, our pro-gelator of GA-Cur showed an enhanced cellular uptake and better inhibition capacity to liver tumor cells than Nap-Cur. Therefore, the GA-Cur could significantly inhibit HepG2 cell growth. Our study provides a novel nanomaterial for liver tumor chemotherapy.