Co-Delivery of siRNA and Docetaxel to Cancer Cells by NLC for Therapy

Abstract

The present study aims to develop a delivery system that can carry small interference RNA (siRNA) with small-molecule chemotherapeutic drugs, which can be used in cancer treatment. The drug delivery system combines the advantages of a therapeutic agent with two different mechanisms to ensure that it is used efficiently for cancer therapy. In this study, a nanostructured lipid carrier system was prepared, Docetaxel was loaded to these systems, and the Eph siRNA was adsorbed to the outer surface. In addition, DOTAP was added to the lipophilic phase to load a positive charge on the lipidic structure for interaction with the cells. Moreover, characterization, cytotoxicity, and transfection procedures were performed on the whole system. This candidate system was also compared to Taxotere, which is the first approved Docetaxel-containing drug on the market. Given the results, it was determined that the particle size of NLC-DTX was 165.3 ± 3.5 nm, the ζ potential value was 38.2 ± 1.7 mV, and the PDI was 0.187 ± 0.024. Entrapment efficacy of nanoparticles was found to be 92.89 ± 0.21%. It was determined that the lipidic system prepared in vitro release analyses were able to provide sustained release and exhibit cytotoxicity, even at doses lower than the dose used for Taxotere. The formulations prepared had a higher level of effect on cells when compared with pure DTX and Taxotere, but they also exhibited time-dependent cytotoxicity. It was also observed that the use of Eph siRNA together with the chemotherapeutic agent via formulation also contributed to this cell death. The results of the present study indicate that there is a promising carrier system in order to deliver hydrophilic nucleic acids, such as siRNA, together with lipophilic drugs in cancer treatment.

Figure 1

Particle size distribution by intensity of cF2, Cf2-DTX, and cF2-DTX/siRNA (n = 3)

Figure 2

Results of ¹H NMR (A1–A3) and FT-IR (B1–B3) analyses of pure DTX, cF2, and cF-DTX formulations.

Figure 3

Differential scanning calorimetry (DSC) thermograms of Dynasan 116, DTX, DOTAP, cF2, and cF2-DTX.

Figure 4

In vitro release of pure DTX and DTX from Taxotere, cF2 formulations, and siRNA release of siRNA/cF2-DTX complex at physiological pH 7.4 and temperature 37 ± 0.5 °C.

Figure 5

Inhibition results of pure DTX, empty formulation, and DTX-loaded formulations on cells for 24 h (A), 48 h (B), and 72 h (C).

Figure 6

(A) Inhibition results of siRNA EpHA1, A2, and B3 alone and combinations on cells at 24, 48, and 72 h and (B) the effect of siRNA EpHA1/A2/B3 combination on cells after loading into cF2 formulation *The concentration of siRNA to be applied was chosen to be 100 ng/100 μL. In single siRNA applications, the concentration of each siRNA is 100 ng/100 μL; in double combinations, it is 50 ng/100 μL; and in triple combinations, it is 33.3 ng/100 μL each.

Figure 7

siRNA complex binding efficiency (top) of cF2 and cF2-DTX formulations and protective effect against serum degradation over time (bottom) of the cF2-DTX formulation.

Figure 8

Transfection of cF2-DTX on MCF-7, MCF-10A, A549, and Beas-2B cells.