Cellular Vesicles: New Insights in Engineering Methods, Interaction with Cells and Potential for Brain Targeting.

Cellular vesicles (CVs) have been proposed as alternatives to exosomes for targeted drug delivery. CVs, prepared from human embryonic kidney 293 cells (HEK-293), C57BL/6 mouse B16F10 skin melanoma cells (B16F10), and immortalized human cerebral microvascular endothelial cells (hCMEC/D3) by liposome technology methods, were characterized for morphology, cytotoxicity, and cell uptake properties. CV brain-targeting potential was evaluated in vitro on the hCMEC/D3 blood-brain barrier (BBB) model, and in vivo/ex vivo. CV sizes were between 135 and 285 nm, and the ζ-potential was negative. The dehydration-rehydration method conferred highest calcein loading and latency to CVs compared with other methods. The increased calcein leakage from CVs when compared with liposomes indicated their poor integrity, which was increased by pegylation. The in vivo results confirmed lower liver uptake by PEG-CVs (compared with nonpegylated) proving that the calcein integrity test is useful for prediction of CV biodistribution, as used for liposomes. The cell uptake of homologous origin CVs was not always higher compared with that of non-homologous. Nevertheless, CVs from hCMEC/D3 demonstrated the highest BBB permeability (in vitro) compared with OX-26 targeted liposomes, and brain localization (in vivo). CVs from hCMEC/D3 cells grown in different media demonstrated decreased interaction with brain cells and brain localization. Significant differences in proteome of the two latter CV types were identified by proteomics, suggesting a potential methodology for identification of organotropism-determining CV components.

Mono and dually decorated nanoliposomes for brain targeting, in vitro and in vivo studies.

PURPOSE: Mono- and dual-decorated (DUAL) liposomes (LIP) were prepared, by immobilization of MAb against transferrin (TfR[OX26 or RI7217]) and/or a peptide analogue of ApoΕ3 (APOe) -to target low-density lipoprotein receptor(LPR)-, characterized physicochemically and investigated for BBB-targeting, in-vitro and in-vivo. METHODS: Human microvascular endothelial cells (hCMEC/D3) were used as BBB model, and brain targeting was studied by in-vivo imaging of DiR-labelled formulations (at two doses and surface ligand densities), followed by ex-vivo organ imaging. RESULTS: LIP diameter was between 100 nm and 150 nm, their stability was good and they were non-cytotoxic. LIP uptake and transport across the hCMEC/D3 cell monolayer was significantly affected by decoration with APOe or MAb, the DUAL exerting an additive effect. Intact vesicle-transcytosis was confirmed by equal transport of hydrophilic and lipophilic labels. In-vivo and ex-vivo results confirmed MAb and DUAL-LIP increased brain targeting compared to non-targeted PEG-LIPs, but not for APOe (also targeting ability of DUAL-LIP was not higher than MAb-LIP). The contradiction between in-vitro and in-vivo results was overruled when in-vitro studies (uptake and monolayer transport) were carried out in presence of serum proteins, revealing their important role in targeted-nanoformulation performance. CONCLUSIONS: A peptide analogue of ApoΕ3 was found to target BBB and increase the targeting potential of TfR-MAb decorated LIP, in-vitro, but not in-vivo, indicating that different types of ligands (small peptides and antibodies) are affected differently by in-vivo applying conditions. In-vitro tests, carried out in presence of serum proteins, may be a helpful predictive "targetability" tool.

Liposomal cisplatin combined with paclitaxel versus cisplatin and paclitaxel in non-small-cell lung cancer: a randomized phase III multicenter trial.

BACKGROUND: Liposomal cisplatin is a new formulation developed to reduce the systemic toxicity of cisplatin while simultaneously improving the targeting of the drug to the primary tumor and to metastases by increasing circulation time in the body fluids and tissues. The primary objectives were to determine nephrotoxicity, gastrointestinal side-effects, peripheral neuropathy and hematological toxicity and secondary objectives were to determine the response rate, time to tumor progression (TTP) and survival. PATIENTS AND METHODS: Two hundred and thirty-six chemotherapy-naive patients with inoperable non-small-cell lung cancer were randomly allocated to receive either 200 mg/m² of liposomal cisplatin and 135 mg/m² paclitaxel (arm A) or 75 mg/m² cisplatin and 135 mg/m² paclitaxel (arm B), once every 2 weeks on an outpatient basis. Two hundred and twenty-nine patients were assessable for toxicity, response rate and survival. Nine treatment cycles were planned. RESULTS: Arm A patients showed statistically significant lower nephrotoxicity, grade 3 and 4 leucopenia, grade 2 and 3 neuropathy, nausea, vomiting and fatigue. There was no significant difference in median and overall survival and TTP between the two arms; median survival was 9 and 10 months in arms A and B, respectively, and TTP was 6.5 and 6 months in arms A and B, respectively. CONCLUSIONS: Liposomal cisplatin in combination with paclitaxel has been shown to be much less toxic than the original cisplatin combined with paclitaxel. Nephrotoxicity in particular was negligible after liposomal cisplatin administration. TTP and survival were similar in both treatment arms.

Prolonged retention of liposomes in the pleural cavity of normal mice and high tumor distribution in mice with malignant pleural effusion, after intrapleural injection.

Background: Intrapleural administration of compounds is a lung targeted, innovative therapeutic strategy for mesothelioma, which can be refined as a route for drug delivery that minimizes the potential for systemic toxicity. However, little is currently known about the retention of liposomal drugs at the site, after such topical administration. Purpose: To evaluate the retention of liposomes in lungs following intrapleural injection, and how this might be modulated by liposome properties and disease progression. Methods: DiR-incorporating liposomes with various lipid compositions and sizes were prepared, characterized (for size distribution and zeta potential) and injected intrapleurally in normal mice and mice with malignant pleural effusion (MPE). DiR retention in pleural cavity was followed by biofluorescence imaging. Results: Experimental results demonstrate that liposome size and PEG-coating, have a significant effect on residence time in the pleural cavity; negative surface charge does not. More than 20% liposomal-DiR is retained 24 d post-injection (in some cases), indicating the high potential towards localized diseases. Ex-vivo liposomal-DiR signal in tumors of MPE mice was similar to signal in liver, suggesting high tumor targeting potential of intrapleurally injected liposomes. Finally, no difference was noticed in liposomal-DiR retention between tumor-inoculated (MPE) and healthy mice, indicating the stability of liposomes in the presence of effusion (in MPE mice). Conclusion: The current study provides novel insights for using liposomes by intrapleural administration for the treatment of lung diseases.

Comparison of liposomal cisplatin versus cisplatin in non-squamous cell non-small-cell lung cancer.

PURPOSE: Liposomal cisplatin was developed to reduce the systemic toxicity of cisplatin, particularly the nephrotoxicity, and it has been used in combination with other agents in pancreatic and head and neck cancers and non-small-cell lung cancer (NSCLC). Our objective was to compare the effectiveness of lipoplatin combined with paclitaxel versus cisplatin with paclitaxel in advanced non-squamous NSCLC. METHODS: During 2007-2010, 202 patients with non-squamous NSCLC (stage IIIB and IV) were recruited from the two participating institutions and divided into two arms: Arm A was treated with liposomal cisplatin 200 mg/m(2) combined with paclitaxel 135 mg/m(2) and Arm B with cisplatin 75 mg/m(2) in combination with paclitaxel 135 mg/m(2), repeated every 2 weeks. The number of cycles administered was 632 (Arm A) and 640 (Arm B), totaling 1,272. RESULTS: A partial response was achieved by 59.22% of Arm A patients versus 42.42% of Arm B, and the difference was statistically significant (P 0.036). The median survival time in months was 10 for Arm A and 8 for Arm B (P 0.1551). After 18 months, the number of surviving patients was double for Arm A versus Arm B. CONCLUSION: Liposomal cisplatin in combination with paclitaxel produces a statistically significantly higher response rate than cisplatin combined with paclitaxel in non-squamous NSCLC.

Paclitaxel and gemcitabine vs. paclitaxel and pegylated liposomal doxorubicin in advanced non-nasopharyngeal head and neck cancer. An efficacy and cost analysis randomized study conducted by the Hellenic Cooperative Oncology Group.

BACKGROUND: The prognosis of patients with recurrent and/or metastatic head and neck cancer (HNC) is poor. Median survival of these patients following chemotherapy is in the range of 6 to 9 months. In the present randomized phase III trial we compared two new combinations containing new drugs with proven activity in phase II studies with patients with HNC. PATIENTS AND METHODS: From November 1999 until November 2004, 166 eligible patients with HNC were enrolled in the study. They were treated with paclitaxel 175 mg/m(2) on day 1 and gemcitabine 1000 mg/m(2) on days 1 and 8 every 3 weeks (group A, 85 patients) or with paclitaxel, as in group A, and pegylated liposomal doxorubicin 40 mg/m(2) on day 1 every 4 weeks (group B, 81 patients). RESULTS: There was no significant difference in response rate (20% versus 29%, P = 0.21), time to disease progression (median; 4.4 months versus 6.0 months, P = 0.09) and survival (median; 8.6 months versus 11.05 months, P = 0.25). Both regimens were generally well tolerated. The most frequently reported side effect, apart from alopecia, was neutropenia. Overall, there was no significant difference in severe toxicity between the two treatment arms. CONCLUSIONS: The present study could not demonstrate a survival benefit with either regimen. Both treatments were well tolerated. Randomized studies comparing each of the two regimens with standard chemotherapy are warranted.