Biomedical subjects

Han Chang Kang

Publications and source records attributed to Han Chang Kang.

3 recordsLinked to original sources

PubMed2006

Polymeric gene transfection on insulin-secreting cells: sulfonylurea receptor-mediation and transfection medium effect.

PURPOSE: In vitro transfection of secreting cells is regarded as one strategy for improved cell engineering/ transplantation. Insulin-secreting insulinoma cell lines or pancreatic beta-cells could be genetically engineered using designed polymeric vectors which are safer than viral vectors. This study investigates the effects of the constituents in transfection media on polymeric transfection. METHODS: Polyplexes conjugated with sulfonylurea (SU) were evaluated under different transfection conditions for gene transfection and their effects on cytotoxicity and insulin secretion. Several components in transfection media specifically associated with the insulin secretion pathway were amino acids, vitamins, Ca2+ and K+. The interactions of the polyplexes with insulin were monitored by surface charge and particle size to monitor how insulin as a protein influences transfection. RESULTS: For an insulin-secreting cell line (RINm5F), polyplexes in Ca2+--containing KRH medium (Ca2+(+)KRH) enhanced transfection and did not cause damage to biological functions. When adding amino acids, vitamins, or K+ or depleting Ca2+ from Ca2+(+)KRH, poly(L-lysine)/DNA complexes showed a greater reduction in transfection than SU receptor (SUR)-targeting polyplexes (SU-polyplex). Positively charged polyplexes interacted with insulin, developing a negative surface charge, and these interactions may cause a decrease in transfection. CONCLUSION: The findings suggest that in vitro and ex vivo polymeric transfection of insulin-secreting cells can be modulated and enhanced by adjusting the transfection conditions.

ATP-Binding Cassette Transporters↗

PubMed2005

Polymeric gene carrier for insulin secreting cells: poly(L-lysine)-g-sulfonylurea for receptor mediated transfection.

Ex vivo transfer of therapeutic genes to cells is one of the potential strategies to prolong the life span of cell transplants. However, relatively safe non-viral carriers have not been extensively investigated due to their lower transfection efficiency. In this study, poly(L-lysine)-g-sulfonylurea varying SU content (PLL-SU) was synthesized to promote gene delivery efficacy to an insulin secreting cell line, RINm5F, which is known to express sulfonylurea receptor (SUR). The polymer formed complexes with a model reporter gene of pCMV-Luc (DNA) and the size of resulting particles was around 100 nm. The transfection efficiency of a polymer synthesized with 5 mol% of SU in the reaction feed (PLL-SU5%) to RINm5F cell was at least 5 times higher than that of PLL. The cytotoxicity of PLL-SU5%/DNA complex was equivalent to that of PLL/DNA complex. PLL-SU5% showed less transfection efficiency than PLL to NIH3T3 and HepG2 cells which are SUR negative. In RINm5F cells, the addition of free SU decreased the transfection efficiency of PLL-SU5%/DNA complex, suggesting that the complex shares the same receptors for SU. The PLL-SU5%/DNA complex seems to be internalized via SUR-mediated endocytosis pathway as suggested by vacuolar ATPases inhibition by Bafilomycin A1. It is noted that RINm5F cells treated with PLL-SU5%/DNA complex secreted more insulin than control, untreated cells, suggesting the insulinotropic effect of SU in PLL-SU5%. In conclusion, PLL-SU may be useful for transfer of therapeutic genes into insulin secreting cells.

Animals↗

PubMed2005

Polymeric gene carriers.

Polymeric gene carriers are a potential alternative to using viral vectors. Polymeric carriers have relatively low immunogenicity and cytotoxicity. In addition, polymeric carriers can accommodate large-size DNA, be conjugated with appropriate functionalities, and be administered repeatedly. In spite of these advantages, polymeric gene carriers have some limitations, such as low gene transfection efficiencies and relatively short duration of gene expression. Therefore, extensive research has been conducted toward the development of efficient polymeric carriers. In this review, we discuss current problems associated with polymeric gene carriers and various strategies against transfection barriers in particular, gene stabilization and protection, cellular targeting, endosomal escaping, nuclear targeting, unpackaging, and biocompatibility. Finally, requirements for future polymeric gene carriers are considered. With all these ongoing efforts, polymeric carriers have become one of the promising gene delivery methods for human gene therapy.

Animals↗