No abstract

Abstract. To design and evaluate the potential use of thioalkylated mannose-modified dendrimer (generation 3; G3) conjugates with α-cyclodextrin (Man-S-α-CDE (G3)) as novel antigen-presenting cell (APC)-selective siRNA carriers, we investigated the RNAi effects of siRNA complexes with Man-S-α-CDEs (G3). Man-S-α-CDE (G3, average degree of substitution of mannose (DSM) 4)/siRNA complex had the potent RNAi effects in both NR8383 cells, a rat alveolar macrophage cell line, and JAWSII cells, a mouse dendritic cell line, through adequate physicochemical properties, mannose receptor (MR)-mediated cellular uptake, and efficient phagosomal escape of the siRNA complex. In addition, cytotoxic activities of the siRNA complexes with α-CDE (G3, DS2) and Man-S-α-CDE (G3, DSM4) were almost negligible up to a charge ratio of 100 (carrier/siRNA). Taken together, these results suggest that Man-S-α-CDE (G3, DSM4) has the potential for a novel APC-selective siRNA carrier.

No abstract

NF-κB and its associated pathways are complicatedly concerned about hepatic homeostasis. Discriminating inhibition of NF-κB signaling has been expected to treat various liver diseases including fulminant hepatitis. To clarify the potential use of thioalkylated mannose-appended dendrimer (generation 3; G3) conjugates with α-cyclodextrin with average degree of substitution of mannose (DSM4) (Man-S-α-CDE (G3, DSM4)) as a novel antigen presenting cell (APC)-specific siRNA carrier, we evaluated the RNAi effect of NF-κB p65 siRNA (sip65) complex with Man-S-α-CDE (G3, DSM4) both in vitro and in vivo. Man-S-α-CDE (G3, DSM4)/sip65 complex significantly suppressed NF-κB p65 mRNA expression and nitric oxide (NO) production from lipopolysaccharide (LPS)-stimulated NR8383 cells, a rat alveolar macrophage cell line, by adequate physicochemical properties and mannose receptor-mediated cellular uptake. Intravenous injection of Man-S-α-CDE (G3, DSM4)/sip65 complex extended the survival rate of LPS-induced fulminant hepatitis model mice. In addition, intravenous administration of Man-S-α-CDE (G3, DSM4)/sip65 complex had the potential to induce the in vivo RNAi effect by significant suppression of mRNA expression of NF-κB p65 and inflammatory cytokines in the liver of fulminant hepatitis model mice induced by LPS/d-galactosamine (d-Gal) without any significant side effects. Also, the serum levels of enzymes were significantly attenuated by injection of Man-S-α-CDE (G3, DSM4)/sip65 complex in fulminant hepatitis model mice. Collectively, these results suggest that Man-S-α-CDE (G3, DSM4) has the potential as a novel APC-selective sip65 carrier for the treatment of LPS/d-Gal-induced fulminant hepatitis in mice.

Pancreatic cancer is one of the most difficult cancers to treat largely because of the inability of anticancer drugs to penetrate into the cancer tissue as the result of the dense extracellular matrix (ECM). On the other hand, bromelain is known to degrade the ECM in cancerous tissue. However, the half-life of bromelain in blood is short, leading to its low accumulation in tissues. Recently, we developed a reversible poly­(ethylene glycol) (PEG) modification technology that is able to improve blood retention of proteins without loss of activity and termed it “Self-assembly PEGylation Retaining Activity (SPRA)” technology. Here, we prepared reversible PEGylated bromelain using SPRA technology (SPRA-bromelain) possessing high activity, long blood retention, and high tumor accumulation and evaluated its potential as a drug delivery system for pancreatic cancer. SPRA-bromelain was prepared by mixing adamantane-modified bromelain and multisubstituted-PEGylated β-cyclodextrins (β-CyDs) containing 2 or 20 kDa PEG chains in water. SPRA-bromelain was formed by a host–guest interaction between adamantane and β-CyD (K c > 104 M–1). SPRA-bromelain showed high in vitro gelatin-degrading activity and enhanced not only the accumulation of fluorescein isothiocyanate (FITC)-dextran (2 MDa) in the tumor but also the in vivo antitumor activities of doxorubicin and doxorubicin encapsulated in PEGylated liposomes (DOXIL) after intravenous administration in tumor-bearing mice. These findings suggest that SPRA-bromelain could be a powerful tool for drug delivery in pancreatic cancer.