Cy Hyun Kim

Self-assembled nanoparticles of hyaluronic acid/poly(dl-lactide-co-glycolide) block copolymer

We synthesized block copolymer composed of hyaluronic acid (HA) and poly(DL-lactide-co-glycolide) (PLGA) (HAbLG) for antitumor targeting. (1)H NMR was employed to confirm synthesis of block copolymer. At (1)H NMR study, HabLG nanoparticles showed HA intrinsic peaks only at D(2)O, indicating that they contained HA as a hydrophilic outer-shell and PLGA as a inner-core. Anti-tumor activity was studied using CD44-overexpressing HCT-116 human colon carcinoma cells. Addition of doxorubicin (DOX)-incorporated nanoparticles to tumor cells resulted in the expression of a strong red fluorescence color while they expressed very weak fluorescence when CD44 receptor was blocked with free HA. Flow cytometry data also showed similar results, indicating that the fluorescence intensity of tumor cells treated with nanoparticles was significantly decreased when CD44 receptor was blocked. These results indicate that HAbLG nanoparticles were able to target CD44-overexpressing tumor cells via receptor-mediated endocytosis.

Antitumor activity of sorafenib-incorporated nanoparticles of dextran/poly(dl-lactide-co-glycolide) block copolymer

Sorafenib-incoporated nanoparticles were prepared using a block copolymer that is composed of dextran and poly(DL-lactide-co-glycolide) [Dexb LG] for antitumor drug delivery. Sorafenib-incorporated nanoparticles were prepared by a nanoprecipitation-dialysis method. Sorafenib-incorporated Dexb LG nanoparticles were uniformly distributed in an aqueous solution regardless of the content of sorafenib. Transmission electron microscopy of the sorafenib-incorporated Dexb LG nanoparticles revealed a spherical shape with a diameter < 300 nm. Sorafenib-incorporated Dexb LG nanoparticles at a polymer/drug weight ratio of 40:5 showed a relatively uniform size and morphology. Higher initial drug feeding was associated with increased drug content in nanoparticles and in nanoparticle size. A drug release study revealed a decreased drug release rate with increasing drug content. In an in vitro anti-proliferation assay using human cholangiocarcinoma cells, sorafenib-incorporated Dexb LG nanoparticles showed a similar antitumor activity as sorafenib. Sorafenib-incorporated Dexb LG nanoparticles are promising candidates as vehicles for antitumor drug targeting.

Effect of 5-aminolevulinic acid-based photodynamic therapy via reactive oxygen species in human cholangiocarcinoma cells

Cancer cells have been reported to exhibit an enhanced capacity for protoporphyrin IX (PpIX) synthesis facilitated by the administration of 5-aminolevulinic acid (ALA). We investigated the effect of ALA-based photodynamic therapy (PDT) on human cholangiocarcinoma cells (HuCC-T1). Since protoporphyrin IX (PpIX), a metabolite of ALA, can produce reactive oxygen species (ROS) under irradiation and then induce phototoxicity, ALA-based PDT is a promising candidate for the treatment of cholangiocarcinoma. When various concentrations of ALA (0.05–2 mM) were used to treat HuCC-T1 cells for 6 or 24 hours, the intracellular PpIX level increased according to the ALA concentration and treatment time. Furthermore, an increased amount of PpIX in HuCC-T1 cells induced increased production of ROS by irradiation, resulting in increased phototoxicity.

Dextran-b-poly(L-histidine) copolymer nanoparticles for ph-responsive drug delivery to tumor cells

Purpose Nanoparticles based on stimuli-sensitive drug delivery have been extensively investigated for tumor targeting. Among them, pH-responsive drug targeting using pH-sensitive polymers has attracted attention because solid tumors have an acidic environment. A dextran-b-poly(L-histidine) (DexPHS) copolymer was synthesized and pH-responsive nanoparticles were fabricated for drug targeting. Methods and results A DexPHS block copolymer was synthesized by attaching the reductive end of dextran to the amine groups of poly(L-histidine). pH-responsive nanoparticles incorporating doxorubicin were fabricated and studied in HuCC-T1 cholangiocarcinoma cells. Synthesis of DexPHS was confirmed by 1H nuclear magnetic resonance spectroscopy, with specific peaks of dextran and PHS observed at 2–5 ppm and 7.4–9.0 ppm, respectively. DexPHS nanoparticles showed changes in particle size with pH sensitivity, ie, the size of the nanoparticles increased at an acidic pH and decreased at a basic pH. DexPHS block copolymer nanoparticles incorporating doxorubicin were prepared using the nanoprecipitation dialysis method. The doxorubicin release rate was increased at acidic pH compared with basic pH, indicating that DexPHS nanoparticles have pH-sensitive properties and that drug release can be controlled by variations in pH. The antitumor activity of DexPHS nanoparticles incorporating doxorubicin were studied using HuCC-T1 cholangiocarcinoma cells. Viability was decreased in cells treated with nanoparticles at acidic pH, whereas cell viability in response to treatment with doxorubicin did not vary according to changes of pH. Conclusion Our results indicated that DexPHS polymeric micelles are promising candidates for antitumor drug targeting.

Synergistic Anticancer Effects of Vorinostat and Epigallocatechin-3-Gallate against HuCC-T1 Human Cholangiocarcinoma Cells

The aim of this study was to investigate the effect of the combination of vorinostat and epigallocatechin-3-gallate against HuCC-T1 human cholangiocarcinoma cells. A novel chemotherapy strategy is required as cholangiocarcinomas rarely respond to conventional chemotherapeutic agents. Both vorinostat and EGCG induce apoptosis and suppress invasion, migration, and angiogenesis of tumor cells. The combination of vorinostat and EGCG showed synergistic growth inhibitory effects and induced apoptosis in tumor cells. The Bax/Bcl-2 expression ratio and caspase-3 and -7 activity increased, but poly (ADP-ribose) polymerase expression decreased when compared to treatment with each agent alone. Furthermore, invasion, matrix metalloproteinase (MMP) expression, and migration of tumor cells decreased following treatment with the vorinostat and EGCG combination compared to those of vorinostat or EGCG alone. Tube length and junction number of human umbilical vein endothelial cells (HUVECs) decreased as well as vascular endothelial growth factor expression following vorinostat and EGCG combined treatment. These results indicate that the combination of vorinostat and EGCG had a synergistic effect on inhibiting tumor cell angiogenesis potential. We suggest that the combination of vorinostat and EGCG is a novel option for cholangiocarcinoma chemotherapy.

Ursodeoxycholic acid-conjugated chitosan for photodynamic treatment of HuCC-T1 human cholangiocarcinoma cells.

Chitosan was hydrophobically modified with ursodeoxycholic acid (UDCA) to fabricate nano-photosensitizer for photodynamic therapy (PDT) of HuCC-T1 cholangiocarcinoma cells. Synthesis of UDCA-conjugated chitosan (ChitoUDCA) was confirmed using (1)H NMR spectra. Chlorin E6 (Ce6) was used as a photosensitizer and incorporated into ChitoUDCA nanoparticles through formation of ion complexes. Morphology of Ce6-incorporated ChitoUDCA nanoparticles was observed using TEM and their shapes were spherical with sizes around 200-400 nm. The PDT potential of Ce6-incorporated ChitoUDCA nanoparticles were studied with HuCC-T1 human cholangiocarcinoma cells. The results showed that ChitoUDCA nanoparticles enhances of Ce6 uptake into tumor cells, phototoxicity, and ROS generation compared to Ce6 itself. Furthermore, Ce6-incorporated ChitoUDCA nanoparticles showed quenching in aqueous solution and sensing at tumor cells. We suggest that Ce6-incorporated ChitoUDCA nanoparticles are promising candidates for PDT of cholangiocarcinoma cells.

Preclinical evaluation of sorafenib-eluting stent for suppression of human cholangiocarcinoma cells

Background Cholangiocarcinoma is a malignant tumor arising from the epithelium of the bile ducts. In this study, we prepared sorafenib-loaded biliary stents for potential application as drug-delivery systems for localized treatment of extrahepatic cholangiocarcinoma. Methods A sorafenib-coated metal stent was prepared using an electrospray system with the aid of poly(ɛ-caprolactone) (PCL), and then its anticancer activity was investigated using human cholangiocellular carcinoma (HuCC)-T1 cells in vitro and a mouse tumor xenograft model in vivo. Anticancer activity of sorafenib against HuCC-T1 cells was evaluated by the proliferation test, matrix metalloproteinase (MMP) activity, cancer cell invasion, and angiogenesis assay in vitro and in vivo. Results The drug-release study showed that the increased drug content on the PCL film induced a faster drug-release rate. The growth of cancer cells on the sorafenib-loaded PCL film surfaces decreased in a dose-dependent manner. MMP-2 expression of HuCC-T1 cells gradually decreased according to sorafenib concentration. Furthermore, cancer cell invasion and tube formation of human umbilical vein endothelial cells significantly decreased at sorafenib concentrations higher than 10 mM. In the mouse tumor xenograft model with HuCC-T1 cells, sorafenib-eluting PCL films significantly inhibited the growth of tumor mass and induced apoptosis of tumor cells. Various molecular signals, such as B-cell lymphoma (Bcl)-2, Bcl-2-associated death promoter, Bcl-x, caspase-3, cleaved caspase-3, Fas, signal transducer and activator of transcription 5, extracellular signal-regulated kinases, MMP-9 and pan-janus kinase/stress-activated protein kinase 1, indicated that apoptosis, inhibition of growth and invasion was cleared on sorafenib-eluting PCL films. Conclusion These sorafenib-loaded PCL films are effective in inhibiting angiogenesis, proliferation and invasion of cancer cells. We suggest that sorafenib-loaded PCL film is a promising candidate for the local treatment of cholangiocarcinoma.

Synergistic effects of 5-aminolevulinic acid based photodynamic therapy and celecoxib via oxidative stress in human cholangiocarcinoma cells.

5-Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) has the potential to kill cancer cells via apoptotic or necrotic signals that are dependent on the generation of intracellular reactive oxygen species (ROS). Celecoxib is an anti-inflammatory drug that induces intracellular ROS generation. We investigated whether the combined application of celecoxib and ALA-PDT improved the efficacy of PDT in human cholangiocarcinoma cells and in tumor bearing mice. In vitro, combined treatment of celecoxib and ALA-PDT increased phototoxicity and intracellular ROS levels after irradiation with 0.75 J/cm2 when compared to ALA-PDT alone. Even though ROS levels increased with 0.25 J/cm2 of irradiation, it did not influence phototoxicity. When heme oxygenase-1, a defensive protein induced by oxidative stress, was inhibited in the combined treatment group, phototoxicity was increased at both 0.25 J/cm2 and 0.75 J/cm2 of irradiation. We identified the combined effect of ALA-PDT and celecoxib through the increase of oxidative stress such as ROS. In vivo, about 40% tumor growth inhibition was observed with combined application of ALA-PDT and celecoxib when compared to ALA-PDT alone. The combined application of ALA-PDT and celecoxib could be an effective therapy for human cholangiocarcinoma. Moreover, use of a heme oxygenase-1 inhibitor with PDT could play an important role for management of various tumors involving oxidative stress.

Effect of surfactant on 5-aminolevulinic acid uptake and PpIX generation in human cholangiocarcinoma cell.

Photodynamic therapy (PDT) is a palliative therapy and has been used to cure cholangiocarcinoma (CC), which has a poor prognosis and limited available curative therapy. PDT was shown to improve the median survival time of advanced-stage patients. Recently, 5-aminolevulinic acid (ALA) has been used as a pro-photosensitizer, which can be transferred to intercellular protoporphyrin IX (PpIX), which is a strong photosensitizer, via the heme pathway. The main limitation of using ALA in PDT is the hydrophilic properties of ALA, which results in low cellular uptake. In this study, non-ionic surfactants, pluronic F68 (PF68) and Tween 80 (TW80), were used to address this limitation. The human CC cell line, HuCC-T1, was cotreated with ALA and different concentrations of surfactants for 4h. The effect of surfactants was evaluated by monitoring the uptake of ALA, the fluorescence intensity of PpIX, and the cell survival rate after suitable light irradiation. Cotreatment with the surfactant resulted in an increased intracellular ALA level, PpIX formation, and phototoxicity.

Aminolevulinic acid derivatives-based photodynamic therapy in human intra- and extrahepatic cholangiocarcinoma cells.

Hexyl-aminolevulinic acid (HALA) was compared with aminolevulinic acid (ALA) in terms of improving ALA-based photodynamic therapy (PDT) for human intra- and extrahepatic cholangiocarcinoma (CCA) HuCC-T1 and SNU1196 cells. Because of the different uptake mechanisms of HALA, a relatively higher amount of protoporphyrin IX (PpIX) was induced in the both CCA cell types at low concentrations of HALA. Furthermore, higher expression of porphobilinogen deaminase, coproporphyrinogen III oxidase, and protoporphyrinogen oxidase, the key enzymes for synthesizing PpIX in the heme biosynthetic pathway, facilitated the exuberant generation of PpIX in HuCC-T1 cells. PpIX accumulation with ALA was markedly different between the two CCA cell types. Even at lower concentrations of ALA, SNU1196 cell successfully synthesized PpIX, due to the higher expression of the ALA transporter, mammalian H (+)/peptide co-transporter PEPT1. Considering the difference of PEPT1 or key enzyme expression, HALA could be a very effective substitute for ALA in doing PDT for cure of CCA.