Bo Sun Kang

Polyethyleneimine-associated polycaprolactone-Superparamagnetic iron oxide nanoparticles as a gene delivery vector

This study describes the synthesis of novel gene delivery vector with low toxicity and high transfection efficiency for magnetofection. The rational design of magnetofection vector called PPMag (PEI-associated polycaprolactone (PCL)-SPIONs) composed of oleic acid (OA) stabilized superparamagnetic iron oxide nanoparticles (SPPIONs) prepared by thermolysis of iron oleate with a combination of hydrophobic PCL and proton absorbing polymer polyethyleneimine (PEI) (PEI-PCL-SPIONs) is described. Encapsulation of amphiphilic PEI with SPIONs not only improves water dispersity of SPIONs, but also allows nucleic acid (NA) condensation and endosomal/lysosomal escape via proton sponge effect after internalization in cells. MTT cytotoxicity assay showed that cell viability was improved compared to conventional PEI-SPIONs. The luciferase activity of magneto-polyplexes treated cells significantly improved compared to both controls revealed that transfection efficiency of PPMag- pCIKlux polyplexes group was improved compared to naked pCIKlux group. The application underneath of a rare earth magnet significantly improve the transfection efficiency (i.e., the luciferase activity doubles) compared to cells without magnet, indicating that sedimentation induced by magnetic field plays important role in accumulation of magneto-polyplexes on cell surfaces. The results demonstrate that PPMag can be used as a novel gene transfection vector to improve transfection efficiency.

Therapeutic effects of dihydroartemisinin and transferrin against glioblastoma

BACKGROUND/OBJECTIVES Artemisinin, a natural product isolated from Gaeddongssuk (artemisia annua L.) and its main active derivative, dihydroartemisinin (DHA), have long been used as antimalarial drugs. Recent studies reported that artemisinin is efficacious for curing diseases, including cancers, and for improving the immune system. Many researchers have shown the therapeutic effects of artemisinin on tumors such as breast cancer, liver cancer and kidney cancer, but there is still insufficient data regarding glioblastoma (GBM). Glioblastoma accounts for 12-15% of brain cancer, and the median survival is less than a year, despite medical treatments such as surgery, radiation therapy, and chemotherapy. In this study, we investigated the anti-cancer effects of DHA and transferrin against glioblastoma (glioblastoma multiforme, GBM). MATERIALS/METHODS This study was performed through in vitro experiments using C6 cells. The toxicity dependence of DHA and transferrin (TF) on time and concentration was analyzed by MTT assay and cell cycle assay. Observations of cellular morphology were recorded with an optical microscope and color digital camera. The anti-cancer mechanism of DHA and TF against GBM were studied by flow cytometry with Annexin V and caspase 3/7. RESULTS MTT assay revealed that TF enhanced the cytotoxicity of DHA against C6 cells. An Annexin V immune-precipitation assay showed that the percentages of apoptosis of cells treated with TF, DHA alone, DHA in combination with TF, and the control group were 7.15 ± 4.15%, 34.3 ± 5.15%, 66.42 ± 5.98%, and 1.2 ± 0.15%, respectively. The results of the Annexin V assay were consistent with those of the MTT assay. DHA induced apoptosis in C6 cells through DNA damage, and TF enhanced the effects of DHA. CONCLUSION The results of this study demonstrated that DHA, the derivative of the active ingredient in Gaeddongssuk, is effective against GBM, apparently via inhibition of cancer cell proliferation by a pharmacological effect. The role of transferrin as an allosteric activator in the GBM therapeutic efficacy of DHA was also confirmed.

Paramagnetic Gd2O3 Nanoparticle-Based Targeting Theranostic Agent for C6 Rat Glioma Cell

This study aimed to synthesize theranostic agent targeting C6 rat glioma cell, which was based on the dextran coated paramagnetic gadolinium oxide nanoparticles D-PGONs conjugated with folic acid FA or paclitaxel PTX. The D-PGONs were synthesized by the in situ coprecipitation method, and the average value of the size distribution was 2.9 nm. FTIR spectroscopy was fulfilled to confirm the conjugations of FA or PTX with D-PGONs. The bioprotective effects of dextran coating and chemotherapeutic effect of PTX in the C6 glioma cell were evaluated by the MTT assay. The differences in uptakes between the synthesized theranostic agents into C6 cells were observed by confocal laser scanning microscopy. In addition, the magnetic contrast enhancement with different concentration of the synthesized agent was compared by the T1-weighted MRI imaging. It was experimentally shown that the synthesized theranostic agent targets C6 cells due to the ligand-receptor-mediated endocytosis and provides enhancement in MR contrast depending on the concentration due to the paramagnetic property of gadolinium nanoparticle. In addition, it was shown by the results of MTT assay that the synthesized nanocomposites were more effective in reducing cell viability than bare gadolinium nanoparticles. In conclusion, it was shown that FA and PTX conjugated D-PGONs could be used as the theranostic agent with paramagnetism and chemotherapeutic property.

Radioprotective effects of delphinidin on normal human lung cells against proton beam exposure

BACKGROUND/OBJECTIVES Exposure of the normal lung tissue around the cancerous tumor during radiotherapy causes serious side effects such as pneumonitis and pulmonary fibrosis. Radioprotectors used during cancer radiotherapy could protect the patient from side effects induced by radiation injury of the normal tissue. Delphinidin has strong antioxidant properties, and it works as the driving force of a radioprotective effect by scavenging radiation-induced reactive oxygen species (ROS). However, no studies have been conducted on the radioprotective effect of delphinidin against high linear energy transfer radiation. Therefore, this study was undertaken to evaluate the radioprotective effects of delphinidin on human lung cells against a proton beam. MATERIALS/METHODS Normal human lung cells (HEL 299 cells) were used for in vitro experiments. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay assessed the cytotoxicity of delphinidin and cell viability. The expression of radiation induced cellular ROS was measured by the 2′-7′-dicholordihydrofluorescein diacetate assay. Superoxide dismutase activity assay and catalase activity assay were used for evaluating the activity of corresponding enzymes. In addition, radioprotective effects on DNA damage-induced cellular apoptosis were evaluated by Western blot assay. RESULTS Experimental analysis, including cell survival assay, MTT assay, and Western blot assay, revealed the radioprotective effects of delphinidin. These include restoring the activities of antioxidant enzymes of damaged cells, increase in the levels of pro-survival protein, and decrease of pro-apoptosis proteins. The results from different experiments were compatible with each to provide a substantial conclusion. CONCLUSION Low concentration (2.5 µM/mL) of delphinidin administration prior to radiation exposure was radioprotective against a low dose of proton beam exposure. Hence, delphinidin is a promising shielding agent against radiation, protecting the normal tissues around a cancerous tumor, which are unintentionally exposed to low doses of radiation during proton therapy.

Targeting chemo-proton therapy on C6 cell line using superparamagnetic iron oxide nanoparticles conjugated with folate and paclitaxel

Abstract Purpose: This report presents novel nanoparticle-based drug delivery system (NPDDS) aiming to targeting chemo-proton therapy (TCPT) to improve the therapeutic efficacy on brain cancer treatments. Materials and methods: A NPDDS, superparamagnetic iron oxide nanoparticles conjugated with folate and paclitaxel, was synthesized and applied to C6 brain cancer cell line that was prepared for TCPT. The characterization of NPDDS was analyzed by transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy. The uptake of NPDDS into the cytoplasm of C6 cells was observed by confocal laser scanning microscopy (CLSM). The therapeutic efficacy of proton beam was quantitatively evaluated by flow cytometry and clonogenic assay at various radiation dose. Results: NPDDS was synthesized in the uniform size distribution with a mean diameter of 5.44 ± 0.70 nm, and it showed no significant cytotoxicity at the concentration lower than 200 ng/mL. Radiosensitization enhancement factors of PTX, D-SPIONs and FA-PTX-D-SPIONs were 1.35, 1.16 and 1.52, respectively. Conclusions: It was demonstrated that TCPT improved the therapeutic efficacy of the proton beam therapy when the synthesized novel NPDDS was administrated. The improvement in therapeutic efficacy was achieved by the synergetic effect of drug delivery increased by FA, radiosensitivity increased by PTX and absorption of proton energy increased by SPIONs.