Mannosylated Cationic Copolymers for Gene Delivery to Macrophages.

Macrophages are desirable targets for gene therapy of cancer and other diseases. Cationic diblock copolymers of polyethylene glycol (PEG) and poly-L-lysine (PLL) or poly{N-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} (pAsp(DET)) are synthesized and used to form polyplexes with a plasmid DNA (pDNA) that are decorated with mannose moieties, serving as the targeting ligands for the C type lectin receptors displayed at the surface of macrophages. The PEG-b-PLL copolymers are known for its cytotoxicity, so PEG-b-PLL-based polyplexes are cross-linked using reducible reagent dithiobis(succinimidyl propionate) (DSP). The cross-linked polyplexes display low toxicity to both mouse embryonic fibroblasts NIH/3T3 cell line and mouse bone marrow-derived macrophages (BMMΦ). In macrophages mannose-decorated polyplexes demonstrate an ≈8 times higher transfection efficiency. The cross-linking of the polyplexes decrease the toxicity, but the transfection enhancement is moderate. The PEG-b-pAsp(DET) copolymers display low toxicity with respect to the IC-21 murine macrophage cell line and are used for the production of non-cross-linked pDNA-contained polyplexes. The obtained mannose modified polyplexes exhibit ca. 500-times greater transfection activity in IC-21 macrophages compared to the mannose-free polyplexes. This result greatly exceeds the targeting gene transfer effects previously described using mannose receptor targeted non-viral gene delivery systems. These results suggest that Man-PEG-b-pAsp(DET)/pDNA polyplex is a potential vector for immune cells-based gene therapy.

Cytotoxic diterpenoids from Salvia yunnanensis.

Forty-six abietane type diterpenoids possessing nine different fused ring systems were characterized from the roots of Salvia yunnanensis, six of which (salyunnanins A-F, 1-6) had different nor-abietane, homo-abietane, seco-abietane, and normal abietane architectures. Their structures were elucidated by comprehensive NMR and MS spectroscopic analyses. The inhibitory activities of these isolates against six human tumor lines were tested in vitro. Several of the compounds exhibited substantial cytotoxicity with IC50 values of 0.86-10.1µM.

Polyelectrolyte Nanogels Decorated with Monoclonal Antibody for Targeted Drug Delivery.

Novel surface-functionalized cross-linked nanogels were developed as a platform to allow conjugation of monoclonal antibodies (mAb) for targeted drug delivery. Well-defined diblock copolymers of poly(ethylene glycol)-b-poly(methacrylic acid) (PEG-b-PMA) with PEG terminal aldehyde functionality were synthesized by atom transfer radical polymerization (ATRP) and characterized by GPC and (1)H NMR. These copolymers were used to prepare nanogels via condensation of PEG-b-PMA with Ca(2+) ions into micelle-like aggregates, cross-linking of the PMA/Ca(2+) cores and removal of Ca(2+) ions. The resulting nanogels represent highly swollen spherical polyelectrolyte particles with free terminal aldehyde functionalities at the nonionic PEG chains. A reductive amination reaction between aldehyde groups and amino groups of mAb resulted in effective conjugation to the nanogels of mAb CC49 against tumor-associated glycoprotein 72 (TAG-72). The mAb retained the binding affinity to bovine submaxillary mucin after conjugation as shown by surface plasmon resonance (SPR). Therefore, aldehyde functionalized nanogels can be linked to mAb using a simple, one-step approach. They may have potential for targeted delivery of diagnostic and therapeutic agents to tumors.