Inhibitory Effects Of Isoliquiritigenin On Proliferation Of Human Cervical Cancer Cells In Vitro And In Vivo

lsoliquiritigenin is a simple chalcone derivative and found in licorice, often used in Chinese medicine, and vegetables such as shallot and bean sprouts. It has various biochemical activities such as antioxidative and superoxide scavenging activities, antiplatelet aggregation effect, inhibitory effect on aldose reductase activity. There are also reports on anticarcinogenic activity of isoliquiritigenin. For example, it was reported to have antitumor promoting activity, inhibitory effect on murine colonic tumorigenesis , anti-angiogenic effect. Isoliquiritigenin is restricted due to its limited aqueous solubility, and liposomal carriers, well known for their potential in drug delivery, have been desired to improve drug penetration and avoid the side effects. In the present study, we prepared the isoliquiritigenin liposome, and examined the proliferation inhibitory effect of isoliquiritigenin on the human cervical cancer cell lines in vitro and in vivo. We also investigated the influences on the cell cycle progression and the gene expression that is associated with the cell cycle.Isoliquiritigenin liposome was prepared by a film-ultrasonic technique; The optimum formation was selected by means of Orthogonal design of experiment; The appearance of liposome was observed by transmission electron microscope and its particle size was determined by Particle Size Analyzer; The liposome and free ISL were separated by Sephadex G-25 exclusion chromatography and the encapsulation efficiency were determined; Centrifugal acceleration experiment was served to proved the liposome stability; The growth inhibition of cell proliferation were evaluated by trypan blue exclusion and MTT method; Cell cycle distributions were measured by flow cytometric assay (FCM); RT-PCR was used to analyze the expression of cyclinB1 mRNA; The inhibitory rate in vivo was evaluated in nude mice by means of human cervical cancer CaSki implantation.The result showed that the mean particle size of the isoliquiritigenin liposome wasabout 233.1 nm with the span of 0.74 .The mean encapsulation efficiency reached 82.57% and the liposome was stable. ISL liposome (5~80umol ? L"1) suppressed proliferation of human cervical cancer cells in a concentration- and time- dependent manner, the inhibition rate of HeLa and SiHa cells reached the maximum at d 3 of culure (the inhibition rate was 83.44 % and 96.14 %). The IC50 of HeLa and SiHa cells exposed to ISL liposome for 48h was 34.24 and 29.82umol ? L"1 respectively ( The IC50 of HeLa and SiHa cells exposed to ISL for 48 h was 75.39 and 69.33umol ? L"1, respectively). ISL (10~80umol ? L"1) suppressed proliferation of CaSki cells in a concentration- and time- dependent manner, the IC50 of CaSki cells exposed to ISL for 48h was 19.33umol 'L"1, the inhibition rate of CaSki cells exposed to ISL (20umol 'L'1) was 82.26 % at d 3 of culture; ISL restrained the cell cycle progression at S and G2 / M phase and down-regulated the expression of cyclinBl. ISL was shown to inhibit human xenograft in nude mice with no apparent toxicity to the animals, the inhibition rate reached 84.6 % at 500 mg ?kg"*?d ~l for 10 days.The result suggested that the selected formulation and technology are stable and practical to prepare the liposome. ISL can significantly inhibit proliferation of the human cervical cancer cells and induced cell cycle arrest at the S and G2 / M phase, and this induction was associated with the decreased the expression of cyclinBl mRNA.