[Show abstract][Hide abstract] ABSTRACT: Polymeric micelles have been proven to be a promising nano-sized system for drug delivery. Understanding its in vivo behaviors at the whole body, tissue and cellular levels is critical for translating this drug delivery system into clinical practice. In this study, the 14.5nm micelles made of polyethylene glycol-phosphatidylethanolamine (PEG-PE) for delivery of doxorubicin and vinorelbine were investigated. Using confocal and two-photon microscopy imaging of live mice or tissue sections, we observed that after systemically administration, the fluorescently labeled PEG-PE micelles encapsulating doxorubicin migrated through blood vessels in entirety into the interstitial tissue, collected by lymphatic vessels, and accumulated in lymph nodes. Importantly, encapsulated drugs such as vinorelbine (Nanovin), preferentially accumulate in lymph nodes when compared to the free drugs. Moreover, the in vivo bioluminescent imaging showed that Nanovin significantly reduced lymph node metastasis rate (P<0.05) in 4T1-luc2 murine breast tumor bearing mice. Finally, we observed that Nanovin enhanced antitumor activity against primary tumors and lung metastases while having low toxicity in various 4T1 tumor models. This study suggests that PEG-PE micelle is a promising drug delivery system for the treatment of lymphatic metastases, and may also have important applications in other lymphatic system-related diseases.
[Show abstract][Hide abstract] ABSTRACT: Metastasis is the main cause of death in cancer patients. To improve the outcomes of patients undergoing a surgery, new adjuvant therapies that can effectively inhibit metastases have to be developed. Studies have shown that flavonoid naringenin, a natural product that is mainly present in grapes and citrus, may contribute to cancer prevention. It has many advantages compared to traditional chemotherapeutic drugs, such as low toxicity. To determine whether naringenin can also inhibit metastases, a breast cancer resection model that mimics clinical situations was established. We found that orally administered naringenin significantly decreased the number of metastatic tumor cells in the lung and extended the life span of tumor resected mice. Flow cytometry analysis revealed that T cells displayed enhanced antitumor activity in naringenin treated mice, with an increased proportion of IFN-γ and IL-2 expressing T cells. In vitro studies further demonstrated that relief of immunosuppression caused by regulatory T cells might be the fundamental mechanism of metastasis inhibition by naringenin. These results indicate that orally administered naringenin can inhibit the outgrowth of metastases after surgery via regulating host immunity. Thus, naringenin can be an ideal surgical adjuvant therapy for breast cancer patients.
[Show abstract][Hide abstract] ABSTRACT: Polymeric micelles had been used as an efficacious carrier system for anti-cancer drug delivery. However, it is not clear whether the molecular mechanism of drug encapsulated in micelles is same as free drug. In this study, the mechanism of vinorelbine loaded in glycol-phosphatidylethanolamine (PEG-PE) micelles (M-Vino) on tumor cells was investigated. Compared with free vinorelbine (Free Vino), M-Vino was more effective in inhibiting the growth of tumor cells in vitro, inducing G(2)/M phase arrest and apoptosis of tumor cells. M-Vino showed a faster entry and higher accumulation in 4T1 cells than free vinorelbine. Therefore, M-Vino destabilized microtubules, induced cell death, and enhanced its cytotoxicity through more intercellular accumulation of vinorelbine.
[Show abstract][Hide abstract] ABSTRACT: To investigate the self-assembly of polyethylene glycol (PEG)-phosphatidylethanolamine (PE) conjugate with water-soluble drugs (doxorubicin hydrochloride, vinorelbine tartrate and vincristine sulfate) and give insight into the mechanism of formation and mode of interaction of the drug with PEG-PE as well as the general principles of self-assembly using pegylated lipid micelles.
One-step self-assembly method to prepare drug-loaded micelles was developed. The micelles were characterized by dynamic light scattering, transmission electron microscopy, encapsulation efficiency, and release study. NMR was used to study molecular assembly of PEG-PE with doxorubicin.
Doxorubicin hydrochloride and vinorelbine tartrate were entrapped into micelles with high efficiency of >99.0% at molar ratios of 1:1 and 2:1 of PEG-PE to drugs, respectively. Drug loading did not measurably perturb either the geometry or the size. It was found that electrostatic interaction and hydrophobic forces are responsible for the intercalation of drugs into PEG-PE micelles. NMR data revealed that the anthracycline ring of doxorubicin was inserted between PE phospholipids, and its amino sugar located in the outer shell of micelle between PEG chains.
Based on our results, the structure and self-assembly mechanism of water-soluble drugs encapsulated in PEG-PE micelles were proposed.
Full-text · Article · Feb 2010 · Pharmaceutical Research