Remarkable inhibitory effects of hybrid liposomes on growth of human colon cancer cells through induction of cell cycle arrest along with apoptosis

BACKGROUND Hybrid liposomes can be prepared by simply sonicating a mixture of vesicular and micellar molecules in buffer solutions. In this study, we investigated the effects of hybrid liposomes on the growth of human colon cancer cells in vitro. METHODS Hybrid liposomes (HL-n, n = 21, 23, 25) composed of L-α-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene(n) dodecyl ethers (C(12)(EO)(n), n = 21, 23, 25) were prepared by the sonication method and their inhibitory effects on growth of human colon cancer HCT116 cells were examined in vitro. RESULTS Significant growth inhibition of HCT116 cells was observed in the presence of HL-n. The fifty percent inhibitory concentration (IC(50)) of HL-n was less than half that of DMPC liposomes. Furthermore, fluorescence microscopic and flow cytometric analyses indicated that the markedly inhibitory effects of HL-n on the growth of HCT116 cells could be attained through the induction of cell cycle arrest at the G(0)/G(1) phase along with apoptotic cell death. CONCLUSION It was found for the first time that HL-n can induce both cell cycle arrest and apoptosis in colon cancer cells. The findings in this study should contribute to novel chemotherapy for colon cancer.