Synthesis, characterization and evaluation of transfection efficiency of dexamethasone conjugated poly(propyleneimine) nanocarriers for gene delivery#.

CONTEXT: Polypropylenimine (PPI), a cationic dendrimer with defined structure and positive surface charge, is a potent non-viral vector. Dexamethasone (Dexa) conveys to the nucleus through interaction with its intracellular receptor. OBJECTIVE: This study develops efficient and non-toxic gene carriers through conjugation of Dexa at various percentages (5, 10 and 20%) to the fourth and the fifth generation PPIs (PPIG4s and PPIG5s). MATERIALS AND METHODS: The 21-OH group of Dexa (0.536 mmol) was modified with methanesulfonyl chloride (0.644 mmol) to activate it (Dexa-mesylate), and then it was conjugated to PPIs using Traut's reagent. After dialysis (48 h) and lyophilization, the physicochemical characteristics of products (PPI-Dexa) including zeta potential, size, buffering capacity and DNA condensing capability were investigated and compared with unmodified PPIs. Moreover, the cytotoxicity and transfection activity of the Dexa-modified PPIs were assessed using Neuro2A cells. RESULTS: Transfection of PPIG4 was close to PEI 25 kDa. Although the addition of Dexa to PPIG4s did not improve their transfection, their cytotoxicity was improved; especially in the carrier to DNA weight ratios (C/P) of one and two. The Dexa conjugation to PPIG5s enhanced their transfection at C/P ratio of one in both 5% (1.3-fold) and 10% (1.6-fold) Dexa grafting, of which the best result was observed in PPIG5-Dexa 10% at C/P ratio of one. DISCUSSION AND CONCLUSIONS: The modification of PPIs with Dexa is a promising approach to improve their cytotoxicity and transfection. The higher optimization of physicochemical characteristics, the better cell transfection and toxicity will be achieved.

Cytotoxic evaluation of different fractions of Salvia chorassanica Bunge on MCF-7 and DU 145 cell lines.

Because of antimicrobial, antioxidant, and anticancer potential, Salvia chorassanica Bunge (Lamiaceae) has been considered as a popular herb in Iranian traditional medicine. Previous studies have shown remarkable cytotoxic properties of the methanol, n-hexane and dichloromethane extract of S. chorassanica on human cervical cancer cells. To seek the therapeutic potentials of S. chorassanica, this study was undertaken to evaluate the cytotoxic activities of various extracts of this plant on human breast MCF-7 and prostate cancer DU 145 cells. The DU 145 cells were exposed to different concentrations of plant extracts (1-200 µg/ml). Cytotoxic activities were examined using alamarBlue(®) assay and apoptosis was assessed by acridine orange/propodium iodide double staining and evaluation of DNA fragmentation by flow cytometry. Our findings indicated that n-hexane and dichloromethane extracts had more cytotoxic activities against DU 145 and MCF-7 cell lines compared with other extracts (P<0.05). The acridine orange/propodium iodide staining showed apoptogenic properties of n-hexane and dichloromethane extracts which was consequently confirmed by flow cytometric histogram that exhibited an increase in sub-G1 peak in treated cells as compared with untreated cancer cell lines. Taken together, these observations demonstrated cytotoxic effects of S. chorassanica extracts on MCF-7 and DU 145 cell lines which is most likely exerted via apoptosis cell death. Therefore, further investigations on S. chorassanica extracts as potential chemotherapeutic agents are warranted.