Stealth monoolein-based nanocarriers for delivery of siRNA to cancer cells

Abstract

This work describes two stealth functionalization strategies for the stabilization of the previously validated dioctadecyldimethylammonium bromide (DODAB):monoolein (MO) siRNA-lipoplexes. These nanocarriers are capable of efficiently incorporating and delivering siRNA molecules to cells in order to silence genes whose expression is implicated in a pathological condition. The main objective was to functionalize these nanocarriers with a coating conferring protection to siRNA in blood without compromising its efficient delivery to cancer cells, validating the potential of DODAB:MO (2:1) siRNA-lipoplexes as therapeutic vectors. We show that the stealth strategy is determinant to achieve a stable and efficient nanocarrier, and that DODAB:MO mixtures have a very promising potential for systemic siRNA delivery to leukemic cells.

Counter ions and constituents combination affect DODAX : MO nanocarriers toxicity in vitro and in vivo

“…In this study we evaluated the effect of cationic liposomes' composition on the viability of several human cell lines, exploiting both the influence of the counter ion (Br − or Cl − ) in the cationic surfactant and the fraction of cationic/neutral lipid of DODAX : MO liposomes, previously validated for nucleic acid delivery (Silva et al 2011(Silva et al , 25 2012(Silva et al , 34 2014 Oliveira et al 2014, 23 2015, 31 Lopes et al 2015 30 ). Our aim was to obtain a comprehensive perspective of the toxicity profile of DODAX : MO liposomes and to understand how changing the lipid mixture influenced cells (metabolism, proliferation, cell death), tissues and organisms.…”

Lipid-based Nanocarriers for siRNA Delivery: Challenges, Strategies and the Lessons Learned from the DODAX: MO Liposomal System

“…However, for high PEG densities, siRNA becomes bound to the outer surface of the liposomes, making them susceptible to premature release into the blood stream [125]. An alternative method is to form the siRNA-lipoplexes with non-PEGylated cationic liposomes and then proceed to the PEG grafting of the formed lipoplexes -the post-PEGylation alternative [116]. This allows a better protection of the siRNA inside the lipid bilayers while taking advantage of the PEG shielding effect necessary for systemic administration.…”

“…These are presumed to be MO-rich domains alternating with DODAB-rich domains (with multilamellar organization), supporting the existence of inverted structures in the liposomal system. The formulation DODAB:MO was first proposed as a non-viral gene delivery system in 2010 by Real Oliveira et al [174], and more recently DODAB:MO and DODAC:MO liposomes were also validated for siRNA delivery [100,116,164] MO-based formulations form small sized siRNAlipoplexes with positive surface charge, were highly internal-ized by the cells and able to silence expression of the model protein eGFP [100]. Nevertheless, the different DO-DAX:MO membrane properties strongly influenced liposomes' bio-interface, defining stability and interaction with cellular models (Fig.…”

The Versatile Dioctadecyldimethylammonium Bromide

“…The approach of combining important biomolecules such as proteins or nucleic acids with DODAB and further stabilizing the hybrids with hydrophilic polymers has been very useful for several biomedical and biotechnological applications. For instance, the delivery of DNA plasmids or small interference RNA (siRNA) to cells requires nanocarrier stability after in vivo administration though too strong stabilization can decrease the carrier efficiency; after characterizing DODAB/monoolein/pDNA or siRNA lipoplexes [88,89], the nanocarriers were pegylated and tested for stability in serum and gene silencing in cultured cancer cells with promising results: pegylation avoided siRNA dissociation from the nanocarriers in human serum and improved transfection efficiency [90]. Stable lipoplexes of small size (100-160 nm) with a positive surface charge (>+45 mV) were readily internalized by human non-small cell lung carcinoma (H1299) cells and were efficient in promoting gene silencing.…”