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Doxorubicin (dox) has been used as anti-cancer agent, but there are disadvantages such as rapid excretion, short retention time and cardiotoxicity. For giving lipophilic properties to dox, it was modified with cholesterol derivatives that were validated as a component of liposomal gene delivery. This article describes the synthesis of dox derivatives (lipo-dox A-D), their cytotoxicity and cellular uptake. In A549, HeLa, MCF7 and MDA MB 231 cell lines, lipo-dox A and lipo-dox B substituted at alcohol group showed similar anti-cancer effect as dox, but lipo-dox C and lipo-dox D substituted at amino group did not. As a result, the amino group of dox seems an important site for its cancer cell inhibition. Lipophilic property of lipo-dox A and lipo-dox B induced more accumulation in cells compared to parent drug. Therefore, the newly synthesized lipo-dox A and lipo-dox B would be a good candidate for anti-cancer agent., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Cholesterol-based fluorescent lipids with ether linker were synthesized using NBD (Chol-E-NBD) or Rhodamine B (Chol-E-Rh), and the usefulnesses as fluorescent probes for tracing cholesterol-based liposomes were validated. The fluorescent intensities of liposomes containing these modified lipids were measured and observed under a microscope. Neither compound interfered with the expression of GFP plasmid, and live cell images were obtained without interferences. Changes in the fluorescent intensity of liposomes containing Chol-E-NBD were followed by flow cytometry for up to 24h. These fluorescent lipids could be useful probes for trafficking of cationic liposome-mediated gene delivery., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Recently, cysteine residue incorporation increased liposome-mediated transfection compared to unmodified peptide. Therefore, we designed novel modified SV40 NLS peptides, homodimeric (NLS-CTHD, NLS-NTHD) and closed structure (cyclic NLS), simply using disulfide bond between cysteines to develop more efficient and safe non-viral gene delivery system. The simple mix of NLS-CTHD among these novel transfection enhancing peptides with DNA increased the gene transfer potency of cationic liposomes more efficiently with no additional cytotoxicity., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Five cholesterol-based cationic lipids were newly synthesized based on cholest-5-en-3β-oxyethane-N,N,N-trimethylammonium bromide (Chol-ETA) structure where the cholesterol backbone is linked to cationic head via various lengths of ether-linked carbon spacer. The transfection efficiency of these compounds was increased in order of three (Chol-PRO)

The new cholesterol-based cationic lipids B, C, and D with an ether linked spacer were synthesized by using aminopropyl chain extension with acrylonitrile. The cholesterol-based cationic lipid A with carbamoyl linkage were also synthesized in order to compare the difference in transfection efficiency of the two linkage types. To this end, GFP expression of these cationic lipids was confirmed respectively.