DNA-Controlled Encapsulation of Small Molecules in Protein Nanoparticles

A nanoparticle can hold multiple types of therapeutic and imaging agents for disease treatment and diagnosis. However, controlling the storage of molecules in nanoparticles is challenging, because nonspecific intermolecular interactions are used for encapsulation. Here, we used specific DNA interactions to store molecules in nanoparticles. We made nanoparticles containing DNA anchors to capture DNA-conjugated small molecules. By changing the sequences and stoichiometry of DNA anchors, we can control the amount and ratio of molecules with different chemical properties in the nanoparticles. We modified the cytotoxicity of our nanoparticles to cancer cells by changing the ratio of encapsulated drugs (mertansine and doxorubicin). Specifically controlling the storage of multiple types of molecules allows us to optimize the properties of combination drug and imaging nanoparticles.

Abstract LB-218: Profiling kinase inhibition in cancer cell extracts using active-site probes and targeted high resolution, accurate mass spectrometry

Protein kinases are enzymes that play key roles in signal transduction pathways which regulate cellular processes including growth, division, differentiation and metabolism. Kinase inhibitors are essential tools used by researchers to understand kinase function and are also therapeutic compounds used in treating cancer and other diseases. Active-site probes are one technology that can be used to determine the specificity and potency of kinase inhibitors. Desthiobiotin-ATP and -ADP are two nucleotide derivatives that have been shown to selectively label kinase active sites. Using these probes to enrich kinase active-site peptides, we identified over 150 kinases from K562 chronic myelogenous leukemia and A549 lung carcinoma cell extracts using high resolution, accurate mass (HR/AM) spectrometry. We also assessed specificity of kinase inhibitors including staurosporine and wortmannin by determining the relative quantitation of kinase active-site peptides after drug treatment. In addition, we validated kinase inhibitor targets using a parallel Western blot workflow. Overall, kinase inhibition measured using high resolution, accurate mass spectrometry had strong correlation with Western blot data and enabled global profiling of kinase inhibitor target and off-targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-218. doi:10.1158/1538-7445.AM2011-LB-218

Opioid-induced tolerance and dependence in mice is modulated by the distance between pharmacophores in a bivalent ligand series

Given the mounting evidence for involvement of delta opioid receptors in the tolerance and physical dependence of mu opioid receptor agonists, we have investigated the possible physical interaction between mu and delta opioid receptors by using bivalent ligands. Based on reports of suppression of antinociceptive tolerance by the delta antagonist naltrindole (NTI), bivalent ligands [mu-delta agonist-antagonist (MDAN) series] that contain different length spacers, and pharmacophores derived from NTI and the mu agonist oxymorphone, have been synthesized and evaluated by intracerebroventricular (i.c.v.) administration in the tail-flick test in mice. In acute i.c.v. studies, the bivalent ligands functioned as agonists with potencies ranging from 1.6- to 45-fold greater than morphine. In contrast, the monovalent mu agonist analogues were substantially more potent than the MDAN congeners and were essentially equipotent with one another and oxymorphone. Pretreatment with NTI decreased the ED(50) values for MDAN-19 to a greater degree than for MDAN-16 but had no effect on MDAN-21. Chronic i.c.v. studies revealed that MDAN ligands whose spacer was 16 atoms or longer produced less dependence than either morphine or mu monovalent control MA-19. On the other hand, both physical dependence and tolerance were suppressed at MDAN spacer lengths of 19 atoms or greater. These data suggest that physical interaction between the mu and delta opioid receptors modulates mu-mediated tolerance and dependence. Because MDAN-21 was found to be 50-fold more potent than morphine by the i.v. route (i.v.), it offers a previously uncharacterized approach for the development of analgesics devoid of tolerance and dependence.