Ultrsound-mediated Destruction Of Oxygen And Paclitaxel Loaded Lipid Microbubbles For The Treatment Of Transplanted Ovarian Cancer Xenografts

PART ONE: THE STUDY ON THE IMAGING AND DRUGDELIVERY OF OXYGEN AND PACLITAXEL LOADEDLIPID MICROBUBBLES IN VIVOSECTION ONETHE STUDY ON THE IMAGING OF OXYGEN ANDPACLITAXEL LOADED LIPID MICROBUBBLES INTRANSPLANTED OVARIAN CANCER XENOGRAFTSObjectives: To investigate the imaging of oxygen and paclitaxelloaded lipid microbubbles in SKOV3ovarian cancer xenografts.Methods: Paclitaxel loaded lipid microbubbls(PLMBs) and oxygenand paclitaxel loaded microbubbles(OPLMBs) were synthesized bymechanical vibration method. The cell suspension derived from SKOV3were inoculated subcutaneously in nude mice to establish human epithelial ovarian carcinoma models. Six model nude mice were randomly dividedinto three groups:(a)Saline group,(b) paclitaxel loaded lipid microbubbles(PLMBs),(c)oxygen and paclitaxel loaded lipid microbubbles (OPLMBs),with0.2ml saline and the corresponding lipid microbubbles being injectedinto the tail vein.The ultrasound images of tumors were observedcontinuously before and after injection within20minutes.Results: The intensity of tumor area in group (b) and (c) began toincrease about3seconds and reached maximum in5seconds.It lastedabout10min,then disappeared gradually.There was no significantdifference between the two groups before and after the injection. Tumor’sdomain echo of group (a) had no significant change before and afterinjection.Conclusions: SKOV3ovarian cancer xenografts can be imaged byPLMBs and OPLMBsSECTION TWOULTRASOUND-MEDIATED OXYGEN AND PACLITAXELLOADED LIPID MICROBUBBLES DESTRUCTION FORDRUG AND OXYGEN RELEASE IN VIVOObjectives: To explore the posibility of ultrasound-mediated oxygenand paclitaxel loaded lipid microbubbles for drug release and downregeulation of HIF-1α protein and P-glycoprotein expression. Methods:35model rats were randomly divided into seven groups:(a)paclitaxel (PTX),(b)paclitaxel loaded lipid microbubbles group (PLMBs),(c) oxygen and paclitaxel loaded lipid microbubbles group (OPLMBs)(d)paclitaxel plus ultrasound group (PTX+US),(e) paclitaxel loaded lipidmicrobubbles plus ultrasound group (PLMBs+US),(f)oxygen andpaclitaxel loaded lipid microbubbles plus ultrasound group (OPLMBs+US),(g)Saline group.5mice in each group. Mice in each group weretreated correspondingly once a day at a dose of20mg/kg for7consecutivedays. Four hours after the last treatment, mice were sacrificed, tumors andtested organs(The heart, liver,spleen, lung, kidney) were collected. Drugconcentrations in various organs were detected by HPLC.The expression ofHIF-1α and P-glycoprotein were assayed by Western Blot.Results: The drug concentrations in tumor tissue of PLMBs+USgroup and OPLMBs+US group were279±77.89μg/g and300.60±93.18μg/g,respectivly, which was significantly higher than the other groups(p <0.05), but there was no significant difference between those two groups(p>0.05). The paclitaxel concentration in liver and spleen weresignificantly higher in PLMBs group and OPLMBs group than PTX group,(p<0.05), ultrasound exposure did not have an effect on the drugconcentrations in liver and spleen. Compared with the Saline controlgroup, the HIF-1α protein and P-glycoprotein expression weresignificantly decreased in all the treatment groups, but the expression was the lowest in OPLMBs+US group (P<0.05)．Conclusions: Ultrasound-mediated oxygen and paclitaxel loaded lipidmicrobubbles destruction enhancing the deposition of paclitaxel in thetumor tissue and down regeulation of HIF-1α protein andP-glycoprotein expression in the tumor.PART TWO: ULTRSOUND-MEDIATED DESTRUCTIONOF OXYGEN AND PACLITAXEL LOADED LIPIDMICROBUBBLES FOR THE SUPPRESSING OFTRANSPLANTED OVARIAN CANCER XENOGRAFTSObjectives: To explore the posibility of ultrasound-mediateddestruction of OPLMBs in treatment ovarian cancer xenografts.Methods: The35modeling mice were randomly divided into7groups:(a)control group (Saline),(b) paclitaxel (PTX),(c) non-drug-loadedmicrobubbles plus ultrasound group (MBs+US),(d) paclitaxel loaded lipidmicrobubbles(PLMBs),(e) oxygen and paclitaxel loaded lipidmicrobubbles(OPLMBs),(f) paclitaxel loaded lipid microbubbles plusultrasound group (PLMBs+US),(g)oxygen and paclitaxel loaded lipidmicrobubbles plus ultrasound group(OPLMBs+US),5mice each group.PTX was administered once a day at a dose of20mg/kg for7consecutivedays. For treatment groups (c),(f), and (g), ultrasound exposure wasperformed immediately post-injection. Tumor diameter was measured once a day until the8th day after treatment. All mice were sacrificed24hoursafter the last day of treatment and the tumors were harvested. Tumor masseswere weighed and the tissue specimens were dissected. The tumor apoptosiswas detected by using TdT mediatedd UTP nick end labeling (TUNEL)method.The expression of VEGF was detected by immunohistochemicaltechnique.Results: Compared with the Saline control group, the tumor masseswere significantly decreased in all the treatment group, but the mass wasthe lowest in OPLMBs+US group(P<0.05). TUNEL andimmunohistochemical analyses of the dissected tumor tissue furtherconfirmed the increased tumor apoptosis and reduced VEGF exprssion inOPLMBs+US group (P<0.05).Conclusion: Ultrasound mediated OPLMBs destruction couldsignificantly inhibit human ovarian cancer SKOV3xenografts growth andinduce tumor apoptosis as well as decrease VEGF expression.