Challenges and opportunities in the delivery of cancer therapeutics

In Search of Effective Anticancer Agents-Novel Sugar Esters Based on Polyhydroxyalkanoate Monomers

Cancer is one of the deadliest illness globally. Searching for new solutions in cancer treatments is essential because commonly used mixed, targeted and personalized therapies are sometimes not sufficient or are too expensive for common patients. Sugar fatty acid esters (SFAEs) are already well-known as promising candidates for an alternative medical tool. The manuscript brings the reader closer to methods of obtaining various SFAEs using combined biological, chemical and enzymatic methods. It presents how modification of SFAE's hydrophobic chains can influence their cytotoxicity against human skin melanoma and prostate cancer cell lines. The compound's cytotoxicity was determined by an MTT assay, which followed an assessment of SFAEs' potential metastatic properties in concentrations below IC50 values. Despite relatively high IC50 values (63.3-1737.6 μM) of the newly synthesized SFAE, they can compete with other sugar esters already described in the literature. The chosen bioactives caused low polymerization of microtubules and the depolymerization of actin filaments in nontoxic levels, which suggest an apoptotic rather than metastatic process. Altogether, cancer cells showed no propensity for metastasis after treating them with SFAE. They confirmed that lactose-based compounds seem the most promising surfactants among tested sugar esters. This manuscript creates a benchmark for creation of novel anticancer agents based on 3-hydroxylated fatty acids of bacterial origin.

Development of vorinostat-loaded solid lipid nanoparticles to enhance pharmacokinetics and efficacy against multidrug-resistant cancer cells

PURPOSE

To investigate whether delivery of a histone deacetylase inhibitor, vorinostat (VOR), by using solid lipid nanoparticles (SLNs) enhanced its bioavailability and effects on multidrug-resistant cancer cells.

METHODS

VOR-loaded SLNs (VOR-SLNs) were prepared by hot homogenization using an emulsification-sonication technique, and the formulation parameters were optimized. The cytotoxicity of the optimized formulation was evaluated in cancer cell lines (MCF-7, A549, and MDA-MB-231), and pharmacokinetic parameters were examined following oral and intravenous (IV) administration to rats.

RESULTS

VOR-SLNs were spherical, with a narrowly distributed average size of ~100 nm, and were physically stable for 3 months. Drug release showed a typical bi-phasic pattern in vitro, and was independent of pH. VOR-SLNs were more cytotoxic than the free drug in both sensitive (MCF-7 and A549) and resistant (MDA-MB-231) cancer cells. Importantly, SLN formulations showed prominent cytotoxicity in MDA-MB-231 cells at low doses, suggesting an ability to effectively counter the P-glycoprotein-related drug efflux pumps. Pharmacokinetic studies clearly demonstrated that VOR-SLNs markedly improved VOR plasma circulation time and decreased its elimination rate constant. The areas under the VOR concentration-time curve produced by oral and IV administration of VOR-SLNs were significantly greater than those produced by free drug administration. These in vivo results clearly highlighted the remarkable potential of SLNs to augment the bioavailability of VOR.

CONCLUSIONS

VOR-SLNs successfully enhanced the oral bioavailability, circulation half-life, and chemotherapeutic potential of VOR.

Pre-Clinical Evaluation of rHDL Encapsulated Retinoids for the Treatment of Neuroblastoma

Despite major advances in pediatric cancer research, there has been only modest progress in the survival of children with high risk neuroblastoma (NB) (HRNB). The long term survival rates of HRNB in the United States are still only 30-50%. Due to resistance that often develops during therapy, development of new effective strategies is essential to improve the survival and overcome the tendency of HRNB patients to relapse subsequent to initial treatment. Current chemotherapy regimens also have a serious limitation due to off target toxicity. In the present work, we evaluated the potential application of reconstituted high density lipoprotein (rHDL) containing fenretinide (FR) nanoparticles as a novel approach to current NB therapeutics. The characterization and stability studies of rHDL-FR nanoparticles showed small size (<40 nm) and high encapsulation efficiency. The cytotoxicity studies of free FR vs. rHDL/FR toward the NB cell lines SK-N-SH and SMS-KCNR showed 2.8- and 2-fold lower IC50 values for the rHDL encapsulated FR vs. free FR. More importantly, the IC50 value for retinal pigment epithelial cells (ARPE-19), a recipient of off target toxicity during FR therapy, was over 40 times higher for the rHDL/FR as compared to that of free FR. The overall improvement in in vitro selective therapeutic efficiency was thus about 100-fold upon encapsulation of the drug into the rHDL nanoparticles. These studies support the potential value of this novel drug delivery platform for treating pediatric cancers in general, and NB in particular.