Calcium-Carbonate Nanocapsules Improve the Efficacy of BEZ235 in Lymphoma a Cell Line: A Promising New Technology of Drug Delivery

Nanotechnology is a promising branch of the medical field, directed to improve diagnostic and therapeutics strategies, applying nanovectors as drug delivery systems. Efficient encapsulation of anticancer drugs in nanocolloids and microcapsules was recently developed by G. Ciccarella research group (1). Based on our collaboration with the Nantional Nanotechnology Laboratory of the University of Salento and our previous experience with target therapies, we encapsulated BEZ235, a phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin inhibitor (mTOR). BEZ235 efficiently blocks the dysfunctional activation of the PI3K/mTOR pathway in cellular and in vivo settings, thus inhibiting the growth and proliferation of various cancer cells, and phase I/II clinical trials were open in solid cancer. However the scarse solubility limited further development of this promising compound. In order to overcome the solubility issue BEZ235-loaded nanocapsules were generated by the stepwise adsorption of oppositely charged polyelectrolytes into biocompatible CaCO3 cores. First nanocapsules were tested for biocompatibility. The exposition of lymphoma cell lines to empty nanocapsules up to 48 hours, did not induce any cititoxicity, confirming their biocompatibility. Second, encapsulated BEZ235 was compared with free-drug to test the cytotoxicity in a T lymphoma cell line (HUT78) by MTT assay (Fig. 1). The results suggested that nanoencapsulated-BEZ235 was extremely efficient compared with free-BEZ235, reaching IC50 just after 5 hours of exposure compared with an IC65% at 48 hours with the free drug. A validated LC-MS/MS method was developed in order to quantify intracellular concentration of BEZ235 over time. Intracellular concentration of BEZ235 in the lymphoma cell line was consistent with biological results since the internalization kinetic and efficiency was increased by the coating. In order to confirm that the encapsuled-BEZ235 was still effective on cell apoptosis, we tested free BEZ and encapsulated BEZ235 at a concentration of 1µM in T cell lymphoma cell lines. Encapsulated-BEZ235 induced apoptosis evidenced by the cleavage of caspase 8, 9 and 3 at an earlier time point compared with free BEZ235 and at significantly lower concentration.