Folate-appended cyclodextrin improves the intratumoral accumulation of existing boron compounds.

In this study, the tumor accumulation and antitumor effect of folate-modified cyclodextrin (ND201) purified with folate receptor (FR) connotated with BSH were examined. ND201 and BSH were stably bound in blood, and the mixing ratio 1:1 was most efficient. ND-BSH showed higher boron concentration (38.5 ppm) than BSH alone (11.25 ppm). The maximum ND-BSH tumor/blood ratio was also markedly higher (6.58) than that of BSH alone (1.04). ND-BSH showed a significant antitumor effect compared with BSH after neutron irradiation.

Synthesis, structure, and evaluation of a ß-cyclodextrin-artificial carbohydrate conjugate for use as a doxorubicin-carrying molecule.

This paper describes the synthesis of a ß-cyclodextrin (ß-CyD) derivative conjugated with a C,C-glucopyranoside containing a benzene unit. Its doxorubicin-inclusion ability and structure are also discussed. SPR analysis revealed that the ß-CyD conjugate had a high inclusion association value of 3.8×10(6)M(-1) for immobilized doxorubicin. NMR structural analysis suggested that its high doxorubicin-inclusion ability was due to the formation of the inclusion complex as a result of the π-π stacking interaction between the benzene ring of the conjugate and the A ring of doxorubicin.

Active Drug Targeting of a Folate-Based Cyclodextrin-Doxorubicin Conjugate and the Cytotoxic Effect on Drug-Resistant Mammary Tumor Cells In Vitro.

Active drug targeting is an effective therapeutic approach for the treatment of malignant cancers and novel types of drug carriers have been developed. In this study, we developed a cyclodextrin (CD)-based novel carrier-drug conjugate, called per-FOL-ß-CD-ss-DOX, which has folic acid (FA) molecules at the end of primary hydroxyl groups of ß-CD and a pH-cleavable spacer with an anticancer drug, doxorubicin (DOX), at the end of secondary hydroxyl groups. This per-FOL-ß-CD-ss-DOX exhibited a significant cellular uptake as compared with the free DOX solution by EMT6/P cells, which activate the expression of folate receptor (FR). Cellular uptake of per-FOL-ß-CD-ss-DOX was significantly inhibited in the presence of FA and was also inhibited at 4°C. The conjugate exhibited remarkable cytotoxic effects in EMT6/AR1 cells, which are resistant to DOX, whereas free DOX solution did not exhibit this effect. These results suggest that per-FOL-ß-CD-ss-DOX can be taken up into cells via FR-related endocytosis and the cleaved DOX derived from it in endosomes could escape the efflux caused by P-glycoprotein, resulting in the cytotoxic effect. Therefore, the drug delivery by per-FOL-ß-CD-ss-DOX may be a useful approach for drug delivery to FR-expressing cells such as drug-resistant malignant cancers.

Design and evaluation of folate-appended α-, ß-, and γ-cyclodextrins having a caproic acid as a tumor selective antitumor drug carrier in vitro and in vivo.

We reported that per-6-folic acid (FA)-appended ß-cyclodextrin (ß-CyD) possessing two caproic acids between FA and a ß-CyD molecule as a spacer (Fol-c2-ß-CyD) could be useful as a promising antitumor drug carrier. However, the effects of the cavity size and the spacer length on the carrier ability are not still known. In this study, we designed and evaluated the FA-appended three kinds of CyDs possessing a caproic acid as a spacer between FA and a CyD molecule (Fol-c1-CyDs) as a tumor targeting carrier for antitumor drugs. The stability constant of the Fol-c1-ß-CyD/doxorubicin (DOX) complex was much higher than those of Fol-c1-α-CyD and Fol-c1-γ-CyD at pH 7.3. Antitumor activity of DOX was increased by the complexation with Fol-c1-ß-CyD, but not with Fol-c1-α-CyD or Fol-c1-γ-CyD in KB cells, a folate receptor-α-positive cell line. Also, Fol-c1-ß-CyD increased antitumor activities of paclitaxel and vinblastine, but not 5-fluorouracil. Furthermore, Fol-c1-ß-CyD accelerated cellular uptake of DOX and inhibited its efflux from KB cells. The Fol-c1-ß-CyD/DOX complex showed much higher antitumor activity than DOX alone after intratumoral and intravenous administrations to tumor-bearing mice with a negligible change of the blood chemistry values. These findings suggest that Fol-c1-ß-CyD could be useful as a tumor-selective carrier for antitumor drugs.

Folate-appended ß-cyclodextrin as a promising tumor targeting carrier for antitumor drugs in vitro and in vivo.

A large number of antitumor drug delivery carriers based on passive targeting and/or active targeting have been developed. However, encapsulation of antitumor drugs into these drug carriers is often complicated, and antitumor activities of these targeting systems are not satisfactory. In the present study, we first prepared heptakis-6-folic acid (FA)-appended ß-cyclodextrin (ß-CyD) possessing two caproic acids between FA and a ß-CyD molecule as a spacer (Fol-c(2)-ß-CyD) and evaluated the potential as a novel tumor targeting carrier for antitumor drugs through a complexation. Fol-c(2)-ß-CyD formed an inclusion complex with doxorubicin (DOX) at a 1:1 molar ratio with a markedly high stability constant (>10(6) M(-1)). Cellular uptake of DOX was increased by the addition of Fol-c(2)-ß-CyD in KB cells, a folate receptor-α (FR-α)-positive cell line. Additionally, Fol-c(2)-ß-CyD increased in vitro antitumor activities of antitumor drugs such as DOX, vinblastine (VBL), and paclitaxel (PTX) in KB cells, but not in A549 cells, a FR-α-negative cell line. The complex of DOX with Fol-c(2)-ß-CyD markedly increased antitumor activity of DOX, not only after intratumoral administration but also after intravenous administration to mice subcutaneously inoculated Colon-26 cells, a FR-α-positive cell line. These findings suggest that Fol-c(2)-ß-CyD could be useful as a promising antitumor drug carrier.

Folate-PEG-appended dendrimer conjugate with α-cyclodextrin as a novel cancer cell-selective siRNA delivery carrier.

We previously reported that of the various polyamidoamine (PAMAM) STARBURST dendrimer (generation 3, G3) (dendrimer) conjugates with cyclodextrins (CyDs), the dendrimer (G3) conjugate with α-CyD having an average degree of substitution of 2.4 (α-CDE (G3)) has the greatest potential for a novel carrier for siRNA in vitro and in vivo. To improve the siRNA transfer activity and the lack of target specificity of α-CDE (G3), we prepared folate-polyethylene glycol (PEG)-appended α-CDEs (G3) (Fol-PαCs) with various degrees of substitution of folate (DSF) and evaluated their siRNA transfer activity to folate receptor (FR)-overexpressing cancer cells in vitro and in vivo. Of the three Fol-PαCs (G3, DSF 2, 4 and 7), Fol-PαC (G3, DSF 4) had the highest siRNA transfer activity in KB cells (FR-positive). Fol-PαC (G3, DSF 4) was endocytosed into KB cells through FR. No cytotoxicity of the siRNA complex with Fol-PαC (G3, DSF 4) was observed in KB cells (FR-positive) or A549 cells (FR-negative) up to the charge ratio of 100/1 (carrier/siRNA). In addition, the siRNA complex with Fol-PαC (G3, DSF 4) showed neither interferon response nor inflammatory response. Importantly, the siRNA complex with Fol-PαC (G3, DSF 4) tended to show the in vivo RNAi effects after intratumoral injection and intravenous injection in tumor cells-bearing mice. The FITC-labeled siRNA and TRITC-labeled Fol-PαC (G3, DSF 4) were actually accumulated in tumor tissues after intravenous injection in the mice. In conclusion, the present results suggest that Fol-PαC (G3, DSF 4) could potentially be used as a FR-overexpressing cancer cell-selective siRNA delivery carrier in vitro and in vivo.

In vitro and in vivo gene delivery mediated by Lactosylated dendrimer/alpha-cyclodextrin conjugates (G2) into hepatocytes.

The purpose of this study is to evaluate in vitro and in vivo gene delivery efficiency of polyamidoamine (PAMAM) starburst dendrimer (generation 2, G2) conjugates with alpha-cyclodextrin (alpha-CDE (G2)) bearing lactose (Lac-alpha-CDE) with various degrees of substitution of the lactose moiety (DSL) as a novel hepatocyte-selective carrier in hepatocytes. Lac-alpha-CDE (DSL 2.6) was found to have much higher gene transfer activity than dendrimer, alpha-CDE, Lac-alpha-CDE (DSL 1.2, 4.6, 6.2 and 10.2) and lactosylated dendrimer (Lac-dendrimer, DSL 2.4) in HepG2 cells, which are dependent on the expression of cell-surface asialoglycoprotein receptor (ASGP-R), reflecting the cellular association of the plasmid DNA (pDNA) complexes. The physicochemical properties of pDNA complex with Lac-alpha-CDE (DSL 2.6) were almost comparable to that with alpha-CDE. Lac-alpha-CDE (DSL 2.6) provided negligible cytotoxicity up to a charge ratio of 150 in HepG2 cells. Lac-alpha-CDE (DSL 2.6) provided gene transfer activity higher than jetPEI-Hepatocyte to hepatocytes with much less changes of blood chemistry values 12h after intravenous administration in mice. These results suggest the potential use of Lac-alpha-CDE (DSL 2.6) as a non-viral vector for gene delivery toward hepatocytes.

Syntheses and doxorubicin-inclusion abilities of beta-cyclodextrin derivatives with a hydroquinone alpha-glycoside residue attached at the primary side.

This paper describes syntheses and doxorubicin-inclusion abilities of beta-cyclodextrin (CyD) derivatives with a hydroquinone alpha-glycoside residue attached at the primary side. The hydroquinone glycoside having an alpha-D-glucosidic or 2-acetamido-2-deoxy-alpha-D-glucosidic linkage became a useful component for providing an alpha-D-glucose- or 2-acetamido-2-deoxy-alpha-D-glucose-beta-CyD conjugate. The surface plasmon resonance analyses of these beta-CyD derivatives for the anticancer agent, doxorubicin, indicated that they had excellent inclusion associations on the order of 10(5 m)-1 for the immobilized doxorubicin.

Design, synthesis and evaluation of D-galactose-beta-cyclodextrin conjugates as drug-carrying molecules.

Several kinds of D-galactose-beta-cyclodextrin conjugates having a phenyl group in the spacers between the D-galactose and beta-cyclodextrin were designed and synthesized as drug-carrying molecules. Their evaluation as drug-carrying molecules was done by measuring the molecular interactions with the anticancer agent, doxorubicin, and with the d-galactose-binding peanut lectin using an SPR optical biosensor. The SPR analyses showed that these conjugates had remarkably high inclusion associations of 10(5) approximately 10(7)M(-1) levels for the immobilized doxorubicin. Their association constants for immobilized peanut lectin were at the level of 10(4) approximately 10(5)M(-1), as we expected. These conjugates will be useful drug-carrying models which can site-specifically carry doxorubicin to the cells containing D-galactose-binding lectin.

Beta-cyclodextrin conjugates with glucose moieties designed as drug carriers: their syntheses, evaluations using concanavalin A and doxorubicin, and structural analyses by NMR spectroscopy.

Three kinds of beta-cyclodextrin derivatives conjugated with glucose moieties, which were expected as models for a drug carrier targeting the drug delivery systems, were designed and synthesized from beta-cyclodextrin and the natural product, 4-hydroxyphenyl-beta-D-glucopyranoside called arbutin. Arbutin was used because it had a phenyl group with a hydroxyl function which could be used to link the glucose moiety to beta-cyclodextrin. The evaluations of these conjugates as the drug-carrying molecules were done by investigating the molecular interactions with the carbohydrate-binding Concanavalin A (Con A) lectin and the anticancer agent, doxorubicin (DXR), using an SPR optical biosensor. The association constants of the conjugates with immobilized Con A were 2.0 x 10(3) approximately 8.8 x 10(3) M(-1). The result showed that the Con A bound to the glucose moieties from arbutin in the conjugates with prospective association constants. The inclusion associations of the conjugates with immobilized DXR reached 2.2 x 10(5) approximately 1.4 x 10(8) M(-1). The extremely high inclusion associations for DXR suggested their potential abilities as drug-carrying molecules for carrying DXR. The NMR analyses indicated that the phenyl group of the conjugates greatly served to increase the inclusion associations for DXR. In their DXR inclusion complexes, the formation of the stacking complexes by the pi;-pi interactions between the phenyl groups and the included DXR also enhanced their inclusion abilities for DXR.

Improvement of gene delivery mediated by mannosylated dendrimer/alpha-cyclodextrin conjugates.

The purpose of this study is to evaluate in vitro and in vivo gene delivery efficiency of polyamidoamine (PAMAM) starburst dendrimer (generation 2, G2) conjugate with alpha-cyclodextrin (alpha-CDE conjugate (G2)) bearing mannose (Man-alpha-CDE conjugates) with the various degrees of substitution of the mannose moiety (DSM) as a novel non-viral vector in a variety of cells. Man-alpha-CDE conjugates (DSM 3.3 and 4.9) were found to have much higher gene transfer activity than dendrimer, alpha-CDE conjugate and Man-alpha-CDE conjugates (DSM 1.1 and 8.3) in various cells, which are independent of the expression of cell surface mannose receptors. Cellular association of pDNA complexes with dendrimer, alpha-CDE conjugate and Man-alpha-CDE conjugate (DSM 3.3) and their cytotoxic effects differed only very slightly. Surface plasmon resonance study demonstrated that the specific binding activity of Man-alpha-CDE conjugates to concanavalin A was not very strong. Much more conjugation of the mannose moiety to alpha-CDE conjugates provided unfavorable physicochemical properties of pDNA complexes for gene transfer, e.g. the low interaction with pDNA, the low enzymatic stability of pDNA and the lack of pDNA compaction. Man-alpha-CDE conjugate (DSM 3.3) provided gene transfer activity higher than dendrimer and alpha-CDE conjugate in kidney 12 h after intravenous injection in mice. These results suggest the potential use of Man-alpha-CDE conjugate (DSM 3.3) as a non-viral vector.

Synthesis of mono-glucose-branched cyclodextrins with a high inclusion ability for doxorubicin and their efficient glycosylation using Mucor hiemalis endo-beta-N-acetylglucosaminidase.

The mono-glucose-branched cyclodextrins having an appropriate spacer between the beta-cyclodextrin and a glucose moiety were synthesized from beta-cyclodextrin and arbutin. They had the significantly high association constants for doxorubicin, the anticancer agent, in the range of 10(5)-10(6)M(-1), and worked as highly reactive glycosyl acceptors for the transglycosylation reaction by endo-beta-N-acetylglucosaminidase of Mucor hiemalis to produce sialo-complex type oligosaccharide-branched cyclodextrins in the high yields of 65-67%.