Cancer-specific gene silencing through therapeutic siRNA delivery with B vitamin-based nanoassembled low-molecular-weight hydrogelators.

This paper describes the synthesis, characterization, and in vitro and in vivo siRNA transfection ability of B vitamin-based cationic clickable bolaamphiphiles (VBs). Our VBs derived from vitamins B2, B3, B5, B6, and B7 formed nanoassembled low-molecular-weight hydrogelators (LMWGs, vitagels). The vitagels VB2, VB6, and VB7 (derived from vitamins B2, B6, and B7, respectively) facilitated delivery of small interfering RNAs (siRNA), efficiently silencing gene expression specifically into cancer cell lines; in addition, the LMWGs derived from vitamins B3, B5, and B6 were biocompatible. An ex vivo study in a mouse model revealed that the siRNA delivered by the vitagel VB7 was located primarily at the site of the tumor. The gene silencing efficiency of vascular endothelial growth factor siRNA delivered by vitagels was dependent on the nature of the vitamin headgroup, the N/P ratio, and, interestingly, the hydrogelation properties of the VBs.

Tissue specific delivery of estrone-conjugated siRNAs.

An estrone phosphoramidite, synthesized in a single step, was directly incorporated at the 5' ends of small interfering RNAs (siRNAs). The resulting estrone-conjugated siRNAs readily pass through cellular membranes and down-regulate the target protein, and show specific distributions in vivo.

Complexation and conjugation approaches to evaluate siRNA delivery using cationic, hydrophobic and amphiphilic peptides.

In this study, we used solid phase synthesis to prepare three kinds of peptides and then formulated their peptide-siRNA complexes and peptide-siRNA conjugates. Both the complexation and conjugation systems were nontoxic and allowed the delivery of siRNA into the cytoplasm without the need for any transfection agents and with subsequent inhibition of gene expression.

Identification and Analysis of the Chloroplast rpoC1 Gene Differentially Expressed in Wild Ginseng.

Panax ginseng is a well-known herbal medicine in traditional Asian medicine, and wild ginseng is widely accepted to be more active than cultivated ginseng in chemoprevention. However, little has actually been reported on the difference between wild ginseng and cultivated ginseng. Thus, to identify and analyze those differences, we used suppressive subtraction hybridization (SSH) sequences with microarrays, realtime polymerase chain reaction (PCR), and reverse transcription PCRs (RT-PCRs). One of the clones isolated in this research was the chloroplast rpoC1 gene, a ß subunit of RNA polymerase. Real-time RT-PCR results showed that the expression of the rpoC1 gene was significantly upregulated in wild ginseng as compared to cultivated ginseng, so, we conclude that the rpoC1 gene may be one of the important markers of wild ginseng.

Evaluation of physicochemical properties, skin permeation and accumulation profiles of salicylic acid amide prodrugs as sunscreen agent.

Various amide prodrugs of salicylic acid were synthesised, and their physicochemical properties including lipophilicity, chemical stability and enzymatic hydrolysis were investigated. In vivo skin permeation and accumulation profiles were also evaluated using a combination of common permeation enhancing techniques such as the use of a supersaturated solution of permeants in an enhancer vehicle, a lipophilic receptor solution, removal of the stratum corneum and delipidisation of skin. Their capacity factor values were proportional to the degree of carbon-carbon saturation in the side chain. All these amides were highly stable in acetonitrile and glycerine. Amide prodrugs were converted to salicylic acid both in hairless mouse liver and skin homogenates. N-dodecyl salicylamide (C12SM) showed the lowest permeation of salicylic acid in skin compared to the other prodrugs, probably due to its low aqueous solubility. It had a high affinity for the stratum corneum and its accumulation was restricted to only the uppermost layer of skin. Thus, this amide prodrug could be a safer topical sunscreen agent with minimum potential for systemic absorption.

Evaluation of salicylic acid fatty ester prodrugs for UV protection.

The purpose of this study was to investigate the physicochemical properties and in vitro evaluation of fatty ester prodrugs of salicylic acid for ultraviolet (UV) protection. The physicochemical properties such as lipophilicity, chemical stability and enzymatic hydrolysis were investigated with the following fatty ester prodrugs of salicylic acid: octanoyl (C8SA), nonanoyl (C9SA), decanoyl (C10SA), lauroyl (C12SA), myristoyl (C14SA) and palmitoyl oxysalicylate (C16SA). Furthermore, their skin permeation and accumulation were evaluated using a combination of common permeation enhancing techniques such as the use of a lipophilic receptor solution, removal of stratum corneum and delipidization of skin. Their k' values were proportional to the degree of carbon-carbon saturation in the side chain. All these fatty esters were highly stable in 2-propanol, acetonitrile and glycerin, but unstable in methanol and ethanol. They were relatively unstable in liver and skin homogenates. In particular, C16SA was mostly hydrolyzed to its parent compound in hairless mouse liver and skin homogenates, suggesting that it might be converted to salicylic acid after its topical administration. In the skin permeation and accumulation study, C16SA showed the poorest permeation in all skins, suggesting that it could not be permeated in the skin. Furthermore, C14SA and C16SA were less accumulated in delipidized skin compared with normal skin or stripped skin, suggesting that these esters had relatively strong affinities for lipids compared with the other prodrugs in the skin. C16SA showed significantly higher dermal accumulation in all skins compared with its parent salicylic acid. Thus, the palmitoyl oxysalicylate (C16SA) might be a potential candidate for UV protection due to its absence of skin permeation, smaller uptake in the lipid phase and relatively lower skin accumulation.

Cationic nucleolipids as efficient siRNA carriers.

We synthesized five novel uridine-based cationic nucleolipids, introducing basic amino acid residues at the 5' position of uridine, through 1,3-dipolar cycloaddition, and hydrophobic alkyl moieties at the 2' and 3' positions, through carbamate linkages. Their lipoplexes delivered siRNAs efficiently to cells, in vitro, without any severe toxicity.

Hemin inhibits hypertensive rat vascular smooth muscle cell proliferation through regulation of cyclin D and p21.

We tested the hypothesis that HO-1 (heme oxygenase-1) activity varied between vascular smooth muscle cells (VSMC) in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. HO-1 levels were measured under baseline and hemin-stimulated conditions and cell proliferation was monitored. Basal HO-1 levels in untreated cells were lower in SHR compared to WKY rats. Treatment with hemin increased HO-1 mRNA and protein levels in the cells obtained from WKY rats compared to that of SHR rats. However, hemin-treatment showed a greater inhibitory effect on VSMC proliferation in SHR rats than in WKY rats. Tin protoporphyrin IX (SnPPIX) showed a greater reversal of the anti-proliferative effect of hemin on cells from SHR rats than WKY. Similarly, VSMC proliferation from SHR was significantly inhibited in VSMC transfected with the HO-1 gene. These inhibitory effects were associated with cell cycle arrest in the G1 phase. The level of cyclin D, and cyclin dependent kinase inhibitor p21 was higher in SHR cells progressing through the G1 phase. Treatment of the cells with hemin down-regulated the expression of cyclin D and up-regulated that of p21. These results indicate that hemin, an HO-1 inducer, may play a more critical role in VSMC proliferation in SHR than WKY.