Liposome-based codelivery of celecoxib and doxorubicin hydrochloride as a synergistic dual-drug delivery system for enhancing the anticancer effect.

Combination therapy with conventional chemotherapeutic drugs strongly demonstrates a good approach to reduce cytotoxicity, resistance, and the dose of the potent anticancer drugs. The purpose of this research was to design and characterize liposome incorporating celecoxib (CEL) and doxorubicin hydrochloride (DOX) and investigate the anti-tumor efficacy of this combination on different tumor cells. A simple comparison study had been performed for liposomes formulation using thin-film hydration method and pH-gradient method. HSPC-incorporated liposomes were chosen for encapsulation of both CEL and DOX. The formulations showed small particle size and polydispersity index with high encapsulation efficiency. DOX/CEL liposomes displayed the strongest cytotoxicity against B16 and MGC80-3 cells in comparison to the corresponding drug solutions. By incorporation of both agents, a significant reduction in IC50 from 0.927 to 0.198 µg/ml and from 0.81 to 0.535 µg/ml against B16 cells and MGC80-3 cells, respectively, was observed. CEL also significantly improved the intracellular retention and accumulation of DOX in vitro. Our data suggest that the developed liposomal formulation proved to be the most effective formulative strategy as a dual drug delivery system for incorporation of both doxorubicin HCL and CEL and could be considered a useful tool for enhancing the therapeutic efficacy of the anticancer drug.

Fabrication of pH/Reduction Sensitive Polyethylene Glycol-Based Micelles for Enhanced Intracellular Drug Release.

At present, the drug is still difficult to release completely and quickly only with single stimulation. In order to promote the rapid release of polymeric micelles at tumor site, pH/reduction sensitive polymers (PCT) containing disulfide bonds and orthoester groups were synthesized. The PCT polymers can self-assemble in water and entrap doxorubicin to form drug-loaded micelles (DOX/PCT). In an in vitro drug release experiment, the cumulative release of DOX/PCT micelles in the simulated tumor microenvironment (pH 5.0 with GSH) reached (89.7 ± 11.7)% at 72 h, while it was only (16.7 ± 6.1)% in the normal physiological environment (pH 7.4 without GSH). In addition, pH sensitive DOX loaded micellar system (DOX/PAT) was prepared as a control. Furthermore, compared with DOX/PAT micelles, DOX/PCT micelles showed the stronger cytotoxicity against tumor cells to achieve an effective antitumor effect. After being internalized by clathrin/caveolin-mediated endocytosis and macropinocytosis, DOX/PCT micelles were depolymerized in intercellular acidic and a reductive environment to release DOX rapidly to kill tumor cells. Additionally, DOX/PCT micelles had a better inhibitory effect on tumor growth than DOX/PAT micelles in in vivo antitumor activity studies. Therefore, pH/reduction dual sensitive PCT polymers have great potential to be used as repaid release nanocarriers for intercellular delivery of antitumor drugs.

Redox-responsive biocompatible nanocarriers based on novel heparosan polysaccharides for intracellular anticancer drug delivery.

Heparosan is a natural precursor of heparin biosynthesis in mammals. It is stable in blood circulation but can be degraded in lysosomes, showing good biocompatibility and long circulation features. So heparosan can be designed as anticancer drug carriers to increase tumor selectivity and improve the therapeutic effect. A novel redox-sensitive heparosan-cystamine-vitamin E succinate (KSV) micelle system was constructed for intracellular delivery of doxorubicin (DOX). Simultaneously, the redox-insensitive heparosan-adipic acid dihydrazide-vitamin E succinate copolymer (KV) was synthesized as control. DOX-loaded micelles (DOX/KSV) with an average particle size of 90-120 nm had good serum stability and redox-triggered depolymerization. In vitro drug release test showed that DOX/KSV micelles presented obvious redox-triggered release behavior compared with DOX/KV. Cytotoxicity and cell uptake were investigated using MGC80-3 tumor cells and COS7 fibroblast-like cells. The cell survival rate of blank micelles was more than 90%, and the cytotoxicity of DOX/KSV in MGC80-3 cells was higher than in COS7 cells, indicating that the carrier has better biocompatibility and less toxicity side effect. The cytotoxicity of DOX/KSV against MGC80-3 cells was significantly greater than that of free DOX and DOX/KV. Furthermore, compared with DOX/KV in MGC80-3 cells, DOX/KSV micelles uptook more anticancer drugs and then released DOX faster into the cell nucleus. The micelles were endocytosed by multiple pathways, but clathrin-mediated endocytosis was the main pathway. Therefore, heparosan polysaccharide could be a potential option as anticancer carrier for enhancing efficacy and mitigating toxicity.

Derma roller® microneedles-mediated transdermal delivery of doxorubicin and celecoxib co-loaded liposomes for enhancing the anticancer effect.

The topical delivery of chemotherapeutics is a promising approach for the management of skin disorders. However, diverse pharmaceutical strategies are essential to allow penetration of large quantities of drugs to tumor tissue. Herein, an attempt was made to investigate the use of Derma roller® microneedles in combination with doxorubicin HCl (DOX) and celecoxib (CEL) co-loaded liposomes as a potential therapeutic approach for the management of melanoma. DOX/CEL co-loaded liposomes/Gels were prepared and characterized. The results showed that microneedle pretreatment with liposomes gel increased DOX penetration into the skin approximately 2-fold compared with the passive delivery. Both CEL liposomes and DOX liposomes caused significant growth inhibition on B16 cells. Besides, DOX/CEL co-loaded liposome was found more cytotoxic than DOX/CEL solution and single drug loaded liposome. The transdermal delivery of DOX/CEL co-loaded liposome successfully inhibited subcutaneous melanoma in female BALB/nude mice, and the co-administration of DOX/CEL with liposomes was better and significantly enhanced the antitumor effect more than single-drug-loaded liposomes. Furthermore, Dermarollers treatment prior to gel application strongly improved the tumor inhibition rate. DOX/CEL co-loaded liposome delivery via microneedles is a promising strategy for skin tumor treatment with targeting inhibition efficiency and negligible side effects.

Elucidation of cellular uptake and intracellular trafficking of heparosan polysaccharide-based micelles in various cancer cells.

Heparosan polysaccharide, known as a heparin precursor, can be used in drug delivery systems due to its good biocompatibility and anti-cancer effect. But few studies on the cellular uptake mechanism of heparosan polysaccharide-based nanocarrier have been investigated. Therefore, the intracellular trafficking and the uptake mechanism of heparosan-based micelles by different tumor cells were investigated in this study. Heparosan-cholesterol amphipathic conjugates (KC) were constructed and doxorubicin (DOX) was loaded to prepare DOX/KC micelles. Different cancer cells were selected to find out the influence on DOX/KC uptake. There was an obvious difference in cytotoxicity and cellular uptake of DOX/KC in various cancer cells. Interestingly, DOX/KC micelles exhibited the strongest cytotoxicity against MGC80-3 cells and displayed highly cellular uptake by B16 cells. The results of the uptake mechanism showed that the internalization of DOX/KC micelles into MGC80-3 cells and A549 cells was mainly through clathrin-mediated endocytosis and macropinocytosis, while micropinocytosis, clathrin-mediated endocytosis and clathrin/caveolae -independent multi-pathways all contributed to the uptake of micelles in B16 cells. Furthermore, after being internalized by MGC80-3 cells, DOX/KC could escape from the lysosome and simultaneously be transported into the nucleus and mitochondria resulting in the greatest cytotoxicity. These results indicate that heparosan-based drug delivery systems may have different uptake and subcellular distribution behavior in tumor cells, and they will achieve the maximum efficacy only in specific kind of cancers.

Designing heparan sulfate-based biocompatible polymers and their application for intracellular stimuli-sensitive drug delivery.

Heparan sulfate (HS) is a kind of natural polysaccharides with good biocompatibility. And as drug carriers, it has some advantages compared to heparin. However, the preparation of HS is cumbersome and difficult, which limits its application in drug delivery. Here, we use modern separation technique combined with chromatography to establish a new preparation method of HS. The molecular weight and degree of dispersion of HS were (1.03 × 104 ±â€¯107) kDa and 1.106, respectively. HS also showed low anticoagulation activity in comparison with heparin. Subsequently, novel redox-sensitive heparan sulfate-cystamine-vitamin E succinate (HS-SS-VES, HSV) micelles were designed to increase tumor selectivity and improve the therapeutic effect of doxorubicin (DOX). DOX-loaded HSV micelles (DOX/HSV) with spherical morphology had average particle size of 90-120 nm and good redox-triggered release behavior. The cell viabilities of blank micelles were >90% in both human breast cancer (MCF7) cells and African green monkey SV40-transformed kidney fibroblast (COS7) cells. However, the cytotoxicity of DOX/HSV in MCF7 cells was higher than that of COS7 cells. Flow cytometry analyses and confocal laser scanning microscopy observation indicated that DOX/HSV micelles were internalized by endocytosis, and then the drug was released quickly and entered the nuclei of tumor cells. The results demonstrate that high-purity HS can be prepared and has the potential to be further used for drug delivery in antitumor applications.