Improved delivery of Mcl-1 and survivin siRNA combination in breast cancer cells with additive siRNA complexes.

This study aimed at investigating the influence of commercial transfection reagents (Prime-Fect, Leu-Fect A, and Leu-Fect C) complexed with different siRNAs (CDC20, HSP90, Mcl-1 and Survivin) in MDA-MB-436 breast cancer cells and the impact of incorporating an anionic additive, Trans-Booster, into siRNA formulations for improving in vitro gene silencing and delivery efficiency. Gene silencing was quantitatively analyzed by real-time RT-PCR while cell proliferation and siRNA uptake were evaluated by the MTT assay and flow cytometry, respectively. Amongst the investigated siRNAs and transfection reagents, Mcl-1/Prime-Fect complexes showed the highest inhibition of cell viability and the most effective siRNA delivery. The effect of various formulations on transfection efficiency showed that the additive with 1:1 ratio with siRNA was optimal achieving the lowest cell viability compared to untreated cells and negative control siRNA treatment (p < 0.05). Furthermore, the combination of Mcl-1 and survivin siRNA suppressed the growth of MDA-MB-436 cells more effectively than treatment with the single siRNAs and resulted in cell viability as low as ~ 20% (vs. non-treated cells). This aligned well with the induction of apoptosis as analyzed by flow cytometry, which revealed higher apoptotic cells with the combination treatment group. We conclude that commercial transfection reagents formulated with Mcl-1/Survivin siRNA combination could serve as a potent anti-proliferation agent in the treatment of breast cancers.

A Polyplex in a Shell: The Effect of Poly(aspartic acid)-Mediated Calcium Carbonate Mineralization on Polyplexes Properties and Transfection Efficiency.

Mineralization by exposure of organic templates to supersaturated solutions is used by many living organisms to generate specialized materials to perform structural or protective functions. Similarly, it was suggested that improved robustness acquired through mineralization under natural conditions could be an important factor for virus survival outside of a host for better transfection of cells. Here, inspired by this fact, we developed a nonviral tricomponent polyplex system for gene delivery capable of undergoing mineralization. First, we fabricated anionic polyplexes carrying pDNA by self-assembly with a lipid-modified cationic polymer and coating by poly(aspartic acid). Then, we submitted the polyplexes to a two-step mineralization reaction to precipitate CaCO3 under various supersaturations. We carried out detailed morphological studies of the mineralized polyplexes and identified which parameters of the fabrication process were influential on transfection efficiency. We found that mineralization with CaCO3 is efficient in promoting transfection efficiency as long as a certain Ca2+/CO32- lower limit ratio is respected. However, calcium incubation can also be used to achieve similar effects at higher concentrations depending on polyplex composition, probably due to the formation of physical cross-links by calcium binding to poly(aspartic acid). We proposed that the improved robustness and transfection efficiency provided by means of mineralization can be used to expand the possible applications of polyplexes in gene therapy.