Research Of Anti-tumor Activity Of Paclitaxel Long-circulating Thermo-sensitive Liposome On Lewis Lung Cancer Mice Models

Objective: To explore paclitaxel long-circulating thermosensitive liposomes(PLTL)’s cytotoxic effects and the ability to induce apoptosis to mouse Lewis lung cancer cells subjected to local hyperthermia on cell level and in vivo animals. To discover PLTL’s inhibiting effects against tumor growth in tumor-bearing animals. Enhanced delivery of paclitaxel to a solid tumor subjected to local hyperthermia was achieved by using long-circulating, thermosensitive liposomes(TSL) and provide scientific experimental basis for further development and utilization of new dosage form of paclitaxel.Methods: In vitro experiment: 1, To cultivate mouse Lewis lung cancer cells in vitro. Mouse Lewis lung cancer cells were treated with paclitaxel(PTX), paclitaxel thermosensitive liposomes(PTL) and PLTL at different concentrations,after adding drug, heating the cell culture plate to temperatures of up to 42.5±0.5 degrees 1 hour immediately, then put it back to in a humidified incubator containing 5% CO2 at 37?C and continue to culture for 24 h, 48 h and 72 h, the cell growth rate wasdetected by MTT assay. 2, Lewis lung cancer cells were treated with PTX, PTL and PLTL at containing 10μg/ml paclitaxel for 72 h,after adding drug, heating the cell culture plate to temperatures of up to(42.5±0.5) degrees 1 hour immediately, then put it back to in a humidified incubator containing 5% CO2 at 37?C and continue to culture for 72 h and the cell apoptosis was detected by flow cytometry. In vivo experiment: 1,By using C57BL/6 mice as model animals and mouse Lewis lung cancer cells were inoculated into the C57BL/6 mice. 2,To treat the Lewis solid tumor-bearing mice with PTX, PTL and PLTL to a solid tumor subjected to local hyperthermia, respectively. 3,Observe the life state of mice during the treatment, the tumor volumes were determined everyday, draw the tumor growth curve of tumor, the tumor quality were determined and calculate the tumor weight inhibition rate of tumor. 4,The tumor tissue fixed, sectioned and stained with a HE staining kit. The morphology of the cells was observed under an optical microscope. 5, Detection and quantification of cell apoptosis by flow cytometry and TUNEL Assay. 6,Analysis on the survival time of tumor-bearing mice and draw survival curves of tumor-bearing mice.Results: In vitro experiment: 1, The inhibition of different drugs on the tumor cells by the MTT method, PLTL and PTX can inhibit the growth of tumors, and the inhibition rate of PTX, PTL, and PLTL on Lewis lung cancer cells is concentration and time-dependent.But, there is no significant difference between PTL and PLTL, p>0.05. 2,Detect cell apoptosis by flow cytometry, PLTL and PTL can induced cell apoptosis and to achieve thermal characteristics. In vivo experiment: 1,C57BL/6 mice from PTL and PLTL treatment group have shown no adverse reactions, and this is the same as mice from saline treatment group. However, C57BL/6 mice injected with clinical PTX have shown adverse reactions including screaming, biting and agitations. According to the tumor growth curve, the inhibition ratio of paclitaxel long circulating thermosensitive liposomes group is the best. 2,Observed by pathology, through the long circulating thermosensitive liposome active targeting treatment, medicine nanoparticles could reach tumor tissue to achieve tumor Inhibition and cause inflammation response. 3,Detect cell apoptosis by flow cytometry and TUNEL Assay, the inhibition of PLTL is best, the inhibition rate is in order: PLTL> PTL > PTX. 4,Survival experiments show that, PLTL can reduce drug side effects, prolong the survival time.Conclusions: 1,The inhibition on Lewis lung cancer cells of PTX, PTL and PLTL is concentration and time-dependent. 2, The effect of PLTL is better than PTX and PTL. The treatment effect on Lewis lung cancer is most obvious, PLTL can reduce drug side effects, prolong the survival time. PLTL to a solid tumor subjected to local hyperthermia can significantly enhance the antitumor activity of paclitaxel, obviously improves the bioavailability of paclitaxel.3,PLTL induce cell apoptosis to achieve tumor inhibition.