Open Access Short Communication and polyoxyethylene(20) sorbitan monolaurate (Tween 20) including antitumor drugs such as 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) have been observed on the growth of glioma cells in vivo . On the other hand, HL composed of DMPC and polyoxyethylene(n)dodecyl ethers (C 12 (EO) n) without any drugs have remarkable inhibitory effects on the growth of various tumor cells including leukemia, lymphoma and colorectal cancer along with apoptosis in vitro , in vivo[8,9] and clinical applications[10,11]. In this study, we examined the inhibitory effects of hybrid liposomes (HL) composed of DMPC and C 12 (EO) 25 on the growth of human prostate cancer cells in vitro. Hybrid liposomes (HL) are nanosized liposomal particles (Figure 1 A) and can be prepared by sonication of a mixture containing 90 mol% DMPC (NOF, Japan) and 10 mol% C 12 (EO) n (n = 25: Nikko Chemicals, Japan) in 5% glucose solution as described previously . The liposomes composed of DMPC alone (DMPC liposomes) were prepared in the same manner as described above. The sample solutions were sterilized using a membrane filter with 0.20 μm pore size. Figure 1B shows the time course of the hydrodynamic diameter (d hy) change for HL using an electrophoretic light scattering spectrophotometer (ELS-Z, Otsuka Electronics, Osaka, Japan). The mean d hy of HL was about 33 nm in diameter with a single and narrow distribution and was stable for 35 days, though d hy of DMPC liposomes gradually increased with time. It is worthy to note that HL having size under 100 nm in diameter could avoid the reticular endothelial system in vivo  and thus should be appropriate for the intravenous administration in vivo and clinical applications. First, we examined the 50% inhibitory concentration (IC 50) of HL on the growth of human prostate (DU145 and PC-3) cancer cells with WST-8 assay [12-14]. The cells (5.0 × 10 4 viable cells/ ml) were seeded into 96 well plates and incubated for 48 hrs in humidified 5% CO 2 at 37 ° C in the presence or absence of HL. Subsequently, the WST-8 solution (Dojindo Laboratories, Japan) was added to each well. After 3 hrs, the absorption at 450 nm was measured with VersaMax Microplate Reader (Molecular Abstract Hybrid liposomes (HL) can be prepared by simply ultrasonicating a mixture of vesicular and micellar molecules in buffer solutions, and contain no organic solvent unlike conventional liposomes. HL have remarkable inhibitory effects on the growth of various tumor cells including leukemia, lymphoma and colorectal cancer along with apoptosis in vitro, in vivo and clinical applications. In this study, we examined the inhibitory effects of HL the growth of human prostate cancer (DU145 and PC-3) cells in vitro. HL composed of L-α-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene (25) dodecyl ethers (C 12 (EO) 25) having nano-sized liposomal particles were produced. Markedly inhibitory effects of HL on the growth of DU145 and PC-3 cells were obtained for the first time. It is noteworthy that HL induced apoptotic death of DU145 and PC-3 cells through activation of caspase-3. This study suggests that HL could be a promising novel agent for the treatment of prostate cancer.
Ueoka, R. (2015). Hybrid Nanoparticles Inhibit Growth of Human Prostate Cancer Cells by Induction of Apoptosis. SOJ Pharmacy & Pharmaceutical Sciences. https://doi.org/10.15226/2374-6866/1/3/00117