Design, preparation and evaluation of different branched biotin modified liposomes for targeting breast cancer.

A series of liposome ligands (Bio-Chol, Bio-Bio-Chol, tri-Bio-Chol and tetra-Bio-Chol) modified by different branched biotins that can recognize the SMVT receptors over-expressed in breast cancer cells were synthesized. And four liposomes (Bio-Lip, Bio-Bio-Lip, tri-Bio-Lip and tetra-Bio-Lip) modified by above mentioned ligands as well as the unmodified liposome (Lip) were prepared to study the targeting ability for breast cancer. The cytotoxicity study and apoptosis assay of paclitaxel-loaded liposomes showed that tri-Bio-Lip had the strongest anti-proliferative effect on breast cancer cells. The cellular uptake studies on mice breast cancer cells (4T1) and human breast cancer cells (MCF-7) indicated tri-Bio-Lip possessed the strongest internalization ability, which was 5.21 times of Lip, 2.60 times of Bio-Lip, 1.67 times of Bio-Bio-Lip and 1.17 times of tetra-Bio-Lip, respectively. Moreover, the 4T1 tumor-bearing BALB/c mice were used to evaluate the in vivo targeting ability. The data showed the enrichment of liposomes at tumor sites were tri-Bio-Lip > tetra-Bio-Lip > Bio-Bio-Lip > Bio-Lip > Lip, which were consistent with the results of in vitro targeting studies. In conclusion, increasing the density of targeting molecules on the surface of liposomes can effectively enhance the breast cancer targeting ability, and the branching structure and spatial distance of biotin residues may also have an important influence on the affinity to SMVT receptors. Therefore, tri-Bio-Lip could be a promising drug delivery system for targeting breast cancer.

Dual-targeting liposomes with active recognition of GLUT5 and αvß3 for triple-negative breast cancer.

At present, chemo- and radiotherapies remain to be the mainstream methods for treating triple-negative breast cancer (TNBC), which is known for poor prognosis and high rate of mortality. Two types of novel dual-targeting TNBC liposomes (Fru-RGD-Lip and Fru+RGD-Lip) that actively recognize both fructose transporter GLUT5 and integrin αvß3 were designed and prepared in this work. Firstly, a Y-shaped Fru-RGD-chol ligand, where a fructose and peptide Arg-Gly-Asp (RGD) were covalently attached to cholesterol, was designed and synthesized. Then, the Fru-RGD-Lip was constructed by inserting Fru-RGD-chol into liposomes, while Fru+RGD-Lip was obtained by inserting both Fru-chol and RGD-chol (with the molar ratio of 1:1) into liposomes. The particle size, zeta potential, encapsulation efficiency and serum stability of the paclitaxel-loaded liposomes were characterized. The results indicated that the paclitaxel-loaded Fru-RGD-Lip had the strongest growth inhibition against GLUT5 and αvß3 overexpressed MDA-MB-231 and 4T1 cells. The cellular uptake of Fru-RGD-Lip on MDA-MB-231 cells and 4T1 cells was 3.19- and 3.23-fold more than that of the uncoated liposomes (Lip). The uptake of Fru+RGD-Lip was slightly lower, giving a 2.81- and 2.90-fold increase than that of Lip in two cell lines, respectively. The mechanism study demonstrated that the cellular uptake of both dual-targeting liposomes was likely to be recognized and mediated by GLUT5 and αvß3 firstly, then endocytosed through comprehensive pathways in an energy-dependent manner. Moreover, Fru-RGD-Lip displayed the maximum accumulation, which was 2.62-fold higher than that of Lip for instance, at the tumor sites compared to other liposomes using in vivo imaging. Collectively, the liposomes co-modified by fructose and RGD have enormous potential in the development of targeted TNBC treatment, especially the covalently modified Fru-RGD-Lip, making it a promising multifunctional liposome.

Liposomes modified with double-branched biotin: A novel and effective way to promote breast cancer targeting.

Although active targeting liposomes with cancer-specific ligands can bind and internalize into cancer cells, only a few high-efficiency liposomes have been developed so far because traditional single branched ligand modified liposomes generally failed to deliver adequate therapeutic payload. In this paper, we broke the traditional design concept and synthesized the double branched biotin modified cholesterol (Bio2-Chol) for the first time. On this basis, different biotin density modified liposomes ((Bio-Chol)Lip, (Bio-Chol)2Lip and (Bio2-Chol)Lip) were successfully prepared and used as active targeting drug delivery systems for the treatment of breast cancer. The in vitro and in vivo breast cancer-targeting ability of these liposomes were systemically studied using paclitaxel (PTX) as the model drug. And the uptake mechanism of (Bio2-Chol)Lip was investigated. The results showed that (Bio2-Chol)Lip had the best breast cancer-targeting ability compared with naked paclitaxel, unmodified Lip, (Bio-Chol)Lip and (Bio-Chol)2Lip. In particular, the relative uptake efficiency (RE) and concentration efficiency (CE) of (Bio2-Chol)Lip were respectively enhanced by 5.61- and 5.06-fold compared to that of naked paclitaxel. Both distribution data and pharmacokinetic parameters suggested that the double branched biotin modified liposome ((Bio2-Chol)Lip) is a very promising drug delivery carrier for breast cancer.

Liposomes actively recognizing the glucose transporter GLUT1 and integrin αv ß3 for dual-targeting of glioma.

The treatment of glioma is a great challenge because of the existence of the blood-brain barrier (BBB). In order to develop an efficient glioma-targeting drug delivery system to greatly improve the brain permeability of anti-cancer drugs and target glioma, a novel glioma-targeted glucose-RGD (Glu-RGD) derivative was designed and synthesized as ligand for preparing liposomes to effectively deliver paclitaxel (PTX) to cross the BBB and target glioma. The liposomes were prepared and characterized for particle size, zeta potential, encapsulation efficiency, release profile, stability, hemolysis, and cell cytotoxicity. Also, the Glu-RGD modified liposomes showed superior targeting ability in in vitro and in vivo evaluation as compared to naked PTX, non-coated, singly modified liposomes and liposomes co-modified by physical blending. The relative uptake efficiency and concentration efficiency were enhanced by 4.41- and 4.72-fold compared to that of naked PTX, respectively. What is more, the Glu-RGD modified liposomes also displayed the maximum accumulation of DiD-loaded liposomes at tumor sites compared to the other groups in in vivo imaging. All the results in vitro and in vivo suggested that Glu-RGD-Lip would be a potential delivery system for PTX to treat integrin αv ß3 -overexpressing tumor-bearing mice.

Ascorbic acid-modified brain-specific liposomes drug delivery system with "lock-in" function.

In this study, a novel brain targeting ascorbic acid (AA) derivative with "lock-in" function was designed and synthesized as a liposome ligand to prepare novel liposomes to achieve the effective delivery of drug formulations to brain via glucose transporter 1 (GLUT1) and the Na+-dependent vitamin C transporter (SVCT2). The liposome was prepared and characterized in terms of the particle size, zeta potential, encapsulation efficiency, release profile, stability, hemolysis and cell cytotoxicity. The preliminary evaluation in vivo demonstrated that the AA-thiamine disulfide system (TDS)-coated liposome had an improved targeting ability and significantly increased the brain concentration of docetaxel (DTX) as compared to the naked docetaxel, the non-coated and the AA-coated liposomes. The relative uptake efficiency and concentration efficiency were enhanced by 3.24- and 5.62-fold compared to that of the naked docetaxel, respectively. Both distribution data and pharmacokinetic parameters suggested that the ascorbic acid thiamine disulfide delivery system was a promising carrier to enhance central nervous system (CNS) drug's delivery ability into brain.

Dual-targeting for brain-specific drug delivery: synthesis and biological evaluation.

Ibuprofen is one of the most potent non-steroid anti-inflammatory drugs (NSAIDs) and plays an important role in the treatment of neurodegenerative diseases. However, its poor brain penetration and serious side effects at therapeutic doses, has hindered its further application. Thus, it is of great interest to develop a carrier-mediated transporter (CMT) system that is capable of more efficiently delivering ibuprofen into the brain at smaller doses to treat neurodegenerative diseases. In this study, a dual-mediated ibuprofen prodrug modified by glucose (Glu) and vitamin C (Vc) for central nervous system (CNS) drug delivery was designed and synthesized in order to effectively deliver ibuprofen to brain. Ibuprofen could be released from the prepared prodrugs when incubated with various buffers, mice plasma and brain homogenate. Also, the prodrug showed superior neuroprotective effect in vitro and in vivo than ibuprofen. Our results suggest that chemical modification of therapeutics with warheads of glucose and Vc represents a promising and efficient strategy for the development of brain-targeting prodrugs by utilizing the endogenous transportation mechanism of the warheads.

First synthesis of 22-oxa-chenodeoxycholic acid analogue.

In this study, we report the first synthesis of 22-oxa-chenodeoxycholic acid analogue via androstenedione and progesterone, in 11 and 8 steps with overall yields of 6.4% and 12.7%, respectively. We anticipate this will help to facilitate the development of new drugs.