Suna Özbaş-Turan

Plasmid DNA-loaded chitosan/TPP nanoparticles for topical gene delivery

Topical application of plasmid DNA represents an attractive route of gene delivery. Although chitosan (CS) has been widely investigated as a gene-carrier, there is very limited information about the skin application of CS-based systems for DNA. This study evaluated pDNA-loaded chitosan nanoparticles (CS-NPs) for skin gene delivery. NPs were prepared by inducing the gelation of CS upon interaction with sodium tripolyphosphate. pSV-β-Gal was used as a reporter gene. The size, surface charge, and the other in vitro characteristics of CS-NPs were examined. Primary human dermal fibroblast cells (HDF) and mouse fibroblast NIH 3T3 cell lines (ATCC CCL-92) were used for in vitro transfection studies. In in vivo study, CS-NPs were applied to the skin of baby and adult Sprague Dawley rats by spreading on the shaved area of the back of animals. During a week animals were sacrificed and skin biopsies were taken for β-Gal expression. β-galactosidase enzyme activity was determined spectrophotometrically at 420 nm. The distribution of β-galactosidase expressing cells within the skin tissue was observed by X-gal histochemical method. β-galactosidase was continuously expressed at the nanoparticle-treated skin during the 7 days. High and continuous β-Gal expressions were obtained with CS-NPs, although it was low in the first day. When a comparison was made between the data of baby and adult rats, markedly high transfection were measured in the skin samples of the baby rats. NPs protected pDNA against the enzyme and serum attacks. In conclusion, CS-NPs showed in vivo transfection potential in rats for skin gene delivery.

Synthesis, Cytotoxicity, and Pro-Apoptosis Activity of Etodolac Hydrazide Derivatives as Anticancer Agents

Etodolac hydrazide and a novel series of etodolac hydrazide‐hydrazones 3–15 and etodolac 4‐thiazolidinones 16–26 were synthesized in this study. The structures of the new compounds were determined by spectral (FT‐IR, 1H NMR, 13C NMR, HREI‐MS) methods. Some selected compounds were determined at one dose toward the full panel of 60 human cancer cell lines by the National Cancer Institute (NCI, Bethesda, USA). 2‐(1,8‐Diethyl‐1,3,4,9‐tetrahydropyrano[3,4‐b]indole‐1‐yl)acetic acid[(4‐chlorophenyl)methylene]hydrazide 9 demonstrated the most marked effect on the prostate cancer cell line PC‐3, with 58.24% growth inhibition at 10−5 M (10 µM). Using the MTT colorimetric method, compound 9 was evaluated in vitro against the prostate cell line PC‐3 and the rat fibroblast cell line L‐929, for cell viability and growth inhibition at different doses. Compound 9 exhibited anticancer activity with an IC50 value of 54 µM (22.842 µg/mL) against the PC‐3 cells and did not display any cytotoxicity toward the L‐929 rat fibroblasts, compared to etodolac. In addition, this compound was evaluated for caspase‐3 and Bcl‐2 activation in the apoptosis pathway, which plays a key role in the treatment of cancer.

Differences between Solution and Membrane Forms of Chitosan on the In Vitro Activity of Fibroblasts.

BACKGROUND Chitosan, a linear polysaccharide, has been recently used in biomedical applications. In vitro studies have demonstrated its effect on cellular growth and its stimulatory action on cellular layer formation. AIMS The present study aims to compare the proliferative effects of chitosan in two forms, membranous and solution forms, on Swiss 3T3 mouse embryonic fibroblasts. STUDY DESIGN In vitro study. METHODS Three experimental groups were formed: cells were cultured in a normal medium without chitosan (Control Group); cells were cultured either in a medium containing 2.0% chitosan in membranous form (Membrane Group) or chitosan solution at a concentration of 2.0% (Solution Group). Two different methods were used in the experiments: cells cultured on the medium containing chitosan in solution or membranous forms (method 1); and chitosan solution or membranous forms were added into the medium containing previously cultured cells (method 2). RESULTS Scanning electron microscopic investigations of the experimental groups revealed cells with well-defined cellular projections, intact cellular membranes and tight intercellular junctions. They were especially prominent in the membrane group of method 1 and in the membrane and solution groups of method 2. Mouse monoclonal anti-collagen 1 primary antibody was used to indicate collagen synthesis. Prominent collagen synthesis was detected in the membrane groups on the 10(th) day of culture for both methods. Bromodeoxyuridine (BrdU) and MTT assays were performed in order to assess cellular proliferation and viability, respectively. BrdU labelling tests indicated a higher proliferation index in the membrane group of method 1 on the 5(th) and 10(th) days. For the second method, the membranous form on the 10(th) day and solution form on the 5(th) day were the most effective groups in terms of cellular proliferation. MTT results reflected a high cellular viability in method 1 on the 5(th) day of treatment with the membranous form, whereas cellular viability was highest in the solution form of method 2 on the 5(th) day. CONCLUSION The membranous form of chitosan induced a significant proliferative effect and increased the ratio of cell-to-cell junctions of Swiss 3T3 mouse embryonic fibroblasts. Conveniently, the solution form also resulted in enhanced cell proliferation and viability compared to the control group. As the solution form is easy to prepare and apply to cells compared to the membrane form, the application of Chitosan directly to media appears to be a convenient alternative for tissue engineering approaches.

Chitosan Nanoparticles in Gene Delivery

Gene therapy is a new alternative treatment method that involves the internalization of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) into target cells to either express or suppress the production of endogenous proteins.

Comparison of VEGF gene silencing efficiencies of chitosan and protamine complexes containing shRNA

VEGF is an angiogenic factor promoting the proliferation and migration of endothelial cells. Inhibition of VEGF by RNAi mechanism is one of the novel and the most important strategies in antiangiogenesis therapy. In this study, the tumor silencing efficiency of ternary complexes after addition of protamine to chitosan complexes containing VEGF targeting shRNA was investigated. Besides chitosan, protamine is an effective gene delivery material. Binary and ternary complexes consisting of chitosan, protamine, and shRNA were prepared to target VEGF, their morphology, size, and zeta potential of the complexes being measured. The average size of the complexes was between 173 and 284 nm and zeta potential was between +10 and 16 mV. In the ternary complexes, size decreased as the chitosan ratio increased; however, its molecular weight had no effect on the size of complexes. HeLa, HEK293, and MCF‐7 cell lines were used for in vitro transfection. VEGF was assayed by ELISA. A higher silencing effect was obtained using ternary complexes. Transgene expression was increased by adding protamine to chitosan complexes. Gene inhibition values in cell lines followed the rank HEK293>HeLa>MCF‐7. The addition of protamine to the chitosan/shRNA (VEGF) complexes increased the knockdown of VEGF genes in the cell lines, and no cytotoxicity was found after the complexes had been incorporated into the cells.

Gene Suppression with Chitosan Nanoparticles

The first tool in gene therapy is DNA internalization for genetic deficiencies, and another tool is used to suppress the biosynthesis of protein by the introduction of antisense oligonucleotides (ASOs) or small interfering ribonucleic acid (siRNAs). ASOs and siRNAs represent an exciting new area for the pharmaceutical industry. These molecules can knock down the expression of target genes through the use of RNA interference (RNAi) pathway.

Effects of different forms of chitosan on intercellular junctions of mouse fibroblasts in vitro.

Chitosan is a linear polysaccharide that has many biomedical applications. We compared the effects of chitosan, in both solution and membranous form, on intercellular adhesion of Swiss 3T3 mouse fibroblasts. Cells were grown as spheroidal cell cultures. Some control cell spheroids were cultured without chitosan and two experimental groups were cultured with chitosan. Chitosan in solution was used for one experimental group and chitosan in membranous form was used for the other. For each group, intercellular adhesion was investigated on days 5 and 10 of culture. Transmission electron microscopy revealed well-defined cellular projections that were more prominent in cells exposed to either membranous or solution forms of chitosan than to the chitosan-free control. Immunocytochemical staining of ICAM-1 and e-cadherin was used to determine the development of intercellular junctions. Compared to the weakly stained control, strong reactions were observed in both chitosan exposed groups at both 5 and 10 days. Cells were treated with 5-bromo-2-deoxyuridine (BrdU) and incubated with anti-BrdU primary antibody to assess proliferation. Both the solution and membranous forms of chitosan increased proliferation at both 5 and 10 days. Cellular viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The MTT assay indicated high cell viability; maximum viability was obtained with the solution form of chitosan at day 5. Chitosan exposure increased the number of intercellular junctions and showed a significant proliferative effect on 3T3 mouse fibroblasts.

594. PDGF-D Inhibition by Using Chitosan:siRNA Complexes in Breast Cancer Model of Rat

Cancers are characterized by the uncontrolled cell growth and angiogenesis. Expression of growth factors like platelet-derived growth factor (PDGF), an angiogenic molecule, increased in many types of human tumors incluiding breast cancer. PDGFs have been implicated in the pathogenesis and angiogenesis of different tumor types.