Release Kinetic Studies of Docetaxel- Loaded Nanodroplets in Human Prostate Cancer Cell Model
R Gupta*, D Cvetkovic, F Chen, L Chen, C Ma, Fox Chase Cancer Center, Philadelphia, PASU-E-U-3 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: In continuation with our earlier studies showing less cell toxicity with docetaxel-loaded nanodroplets when compared to free docetaxel, the purpose of this study was to investigate the release kinetics of docetaxel-loaded nanodroplets using human prostate cancer LNCaP cells.
Methods:Cell proliferation/cytotoxicity of docetaxel-loaded nanodroplets and free docetaxel were assessed by Cell proliferation reagent WST-1 (Roche). LNCaP cells (5x103 /well) were seeded in 96-well plates. After 24 hours, adhered cells were exposed to free docetaxel and encapsulated docetaxel (in separate experiments) at 37°C for different time intervals (2 min, 5 min, 15min, 30 min, 1h, 3h, 6h, 12 h, and 3 days). The docetaxel concentration of 100nM was chosen to be consistent with our published data and in vivo experiments. After specific time points, cells were washed with phosphate buffer saline and fresh media with serum was added. Cells were then allowed to grow for 3 days at 37°C and assay was performed using WST-1 (Fig.1). The development of orange color was read 3h after addition of WST-1 reagent at 450nm on the Envision 2102 Multilabel Reader (Fig.2). The data were expressed as a percentage of untreated/control cells. The experiments were repeated two times.
Results:Cell viability was ~50% when incubated with docetaxel-loaded nanodroplets for 2 minutes; it decreased to ~30% until 1h, stabilized up to 6 h (~ 30%) and then again increased to ~42% up to 3 days. However, for same equivalent concentration of free docetaxel, only ~20% cells survived irrespective of their incubation time (Fig.3).
Conclusion:The results indicated that the release of docetaxel from nanodroplets is time dependent. These studies will be helpful in elucidating the mechanism(s) of interaction/uptake of encapsulated docetaxel by cancer cells and further help in designing in vivo experiments for prostate cancer therapy using pHIFU and encapsulated docetaxel.