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.