Proapoptotic lipid nanovesicles: Synergism with paclitaxel in human lung adenocarcinoma A549 cells Nitin Joshi, Thanigaivel Shanmugam, Anubhav Kaviratna, Rinti Banerjee ⁎ WRCBB, Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai-400076, India abstract article info Article history: Received 28 January 2011 Accepted 17 July 2011 Available online 23 July 2011 Keywords: Lung cancer Proapoptotic lipid nanovesicles Paclitaxel Phosphatidylserine Aerosol Combination chemotherapy The present study focuses on the development and evaluation of phosphatidylserine based proapoptotic lipid nanovesicles (PSN-PTX) as aerosols for synergistic activity with paclitaxel against lung cancer. PSN-PTX showed a unimodal size distribution of the particles (100–200 nm), negative surface charge of -29 mV and high encapsulation efficiency of paclitaxel (82%) with 19% of it releasing in 48 h. PSN-PTX was found to be highly surface active as compared to Taxol®, marketed formulation of paclitaxel, whose surface activity was found to be detrimental for pulmonary mechanics. PSN-PTX also showed high airway patency in capillary surfactometer unlike Taxol®, suggesting its ability to mimic pulmonary surfactant functions. High deposition of PSN-PTX in lower impingement chamber of twin impinger upon nebulization suggested it to be capable of reaching the terminal regions of the lungs. Nanovesicles showed facilitated and ATP dependent active uptake by A549 cells. The combination of phosphatidylserine nanovesicles and paclitaxel as PSN-PTX enhanced cytotoxicity in A549 cell line showing an IC 50 of 18 nM which is10-50 folds less than the IC 50 values observed for blank phosphtidylserine nanovesicles and paclitaxel alone. Further, the combination index was found to be less than one which indicates a synergism of the two components. DNA fragmentation study showed that blank phosphatidylserine nanovesicles induce apoptosis in A549 cells and hence behave as proapoptotic nanovesicles in the combination therapy. Overall, these studies suggest the therapeutic potential and advantages of combination chemotherapy of proapoptotic lipid nanovesicles with encapsulated paclitaxel and their feasibility for aerosol administration in the treatment of lung cancer. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Lung cancer constitutes the maximum percentage of deaths among those caused by different cancers in the world [1]. The traditional treatment methods include surgical resection, radiation treatment and chemotherapy, especially in advanced cases. Inspite of all these existing treatment regimens, the survival rates of lung cancer patients remain poor [2]. Chemotherapy leads to high systemic toxicity and poor bioavailability of the chemotherapeutic agents owing to their non specific depositions. Moreover, since the development of cancer or any neoplasm involves multiple and parallel occurring molecular mecha- nisms and pathways, single agent chemotherapy doesn't offer much advantage to the patient. In order to circumvent these problems associated with conventional chemotherapy, a better and advanced therapeutic system is required, that can be efficiently and specifically targeted to the lungs with the maximum tolerable dosage, can be retained and can offer a more efficacious treatment by combining the therapeutic potential of multiple active agents resulting in a synergistic cytotoxic effect. Liposomes or lipid nanovesicles as drug carriers have been studied extensively and have been proven to be efficient for the delivery of several antineoplastic agents. In this paper, we developed lipid nanovesicles which are proapoptotic i.e. capable of promoting and inducing apoptosis by themselves, and determined whether they can result in synergistic combination chemotherapy with paclitaxel against human non small cell lung adenocarcinoma cells. The proapoptotic nature of the nanovesicles is attributed to phosphatidylserine, an apoptosis inducing lipid which has been incorporated as one of the main components in the nanovesicle. The formulation therefore was designed with the aim of combination chemotherapy of phosphatidylserine and paclitaxel. Paclitaxel is a potent anticancer drug used for the first line treatment of lung cancer. It is a diterpenoid pseudoalkaloid and has a unique mechanism of action which involves the stabilization of microtubules resulting in a mitotic arrest in the G2M phase of cell cycle [3]. Taxol®, the current dosage form of paclitaxel comprises of paclitaxel associated with 50:50 (v/v) Cremophor® EL (polyoxyethylated castor oil) and dehydrated alcohol, to increase the solubility. However, this Cremophor® EL based paclitaxel formulation is marked by serious complications causing severe anaphylactoid hypersensitivity reactions, neurotoxicity, cardiotoxicity, nephrotoxicity, hyperlipidaemia, abnormal lipoprotein patterns, erythro- cyte aggregation, and peripheral neuropathy [4]. Owing to its highly Journal of Controlled Release 156 (2011) 413–420 ⁎ Corresponding author at: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai-400067, India. Tel.: + 91 22 2576 7868 (Direct), 2572 2545x7868; fax: + 91 22 2572 3480. E-mail address: rinti@iitb.ac.in (R. Banerjee). 0168-3659/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jconrel.2011.07.025 Contents lists available at ScienceDirect Journal of Controlled Release journal homepage: www.elsevier.com/locate/jconrel NANOMEDICINE