Fig. 6

Cellular uptake, intracellular distribution, and cytotoxicity of nanoparticle-paclitaxel–small interfering RNA (NP-TAX–siRNA). a Cellular uptake of NP-TAX–siRNA. Confocal microscopic images of MCF-7 cells treated with NP-TAX–siRNA for 6 h. Cell nucleuses (blue) were stained by DAPI, cytomembrane was labeled with DiO green fluorescence, and siRNA was labeled with Cy5 red fluorescence. b and c Gene silencing ability of NP-TAX–siRNA. MCF-7 cells were treated with free metadherin (MTDH)-siRNA and NP-TAX–siRNA in serum-free media for 6 h. After 48 h, the mRNA levels of MTDH were measured by real-time polymerase chain reaction (RT-PCR) (b). The expression of MTDH protein was analyzed by Western blot (c). d and e Cell viability of MCF-7 (d) and MDA-MB-435S (e) breast cancer cells was measured by using Cell Counting Kit (CCK) assay. Cells were incubated with different drug formulations (Saline, Blank NPs, Free siRNA, Free TAX, NP-siRNA, NP-TAX, and NP-TAX–siRNA) at 37 °C for 48 h. The cell viability of saline was set as 100%. Each bar represents the mean ± standard deviation of three replicates. *P <0.05