Interaction Between Haematoporphyrin,Microbubble And Cisplatin Under High Intensity Ultrasound Field

Background and ObjectiveChemotherapy combined with ultrasound is a clinically effective tumor therapy.The high intensity focused utrasound(HIFU) technology has obtained great improvement over these years.Ultrasound can expanse vascular and accelerate blood circulation to increase the concentration of drugs in tumor tissues;It catalysis these chemotherapy drugs to react with deoxyribonucleic acid of tumor cells to rise chemotherapy efficacy;besides, it inhibites deoxyribonucleic acid reparation as well as multi-drug resistant P-glucoprotein so as to augment cells sensitivity towards these drugs and decrease/reverse drug resistance.Sonodynamic therapy(SDT),following operation,radiotherapy and chemotherapy,is a newly emerging tumor treatment regimen with characteristics such as non-invasive,low cytotoxicity and selective killing.YU proposed "sonosensitizer-antitumor drug-ultrasound" regime is a new resistant tumor therapy of great potential which we should research on.Several solid tumors treatment including the ovarian cancer could benefit from this regime.While studying the acoustic contrast agent,researchers found it could realize targeted drug releasing as a drug carrier thus attract wide attention in the professional level.It not only produces destructive biological effects on tumor tissues by ultrasound-induced rupture pulse,but also has synergistic effect with cytotoxic drugs by targeted releasing.In conclusion,"sonosensitizer-antitumor drug-ultrasound" regime might be a new anticancer therapy in clinical application.However,sonochemistry studies pointed out:ultrasonic cavitation and its production free radicals might breakdown/alter molecular structures of anticancer drugs and affect chemical reaction rate/process,which will result in unexpected therapeutic efficacy from combination treatment. Sonosensitizers have definite intensified effect on cavitation.Microbubbls enhanced ultrasonic cavitation lead to large mounts of free radicals,whose previous investigations was based on relatively lower intensity and cannot provide more references.When study cytotoxicity of anticancer drugs in the high intensity focused ultrasound with the presence of sonosensitizer haematoporphyrin and microbubble,we have to investigate their interactions.In our research,we investigated if there were large mounts of free radicals produced in the interaction between HIFU,microbubble, haematoporphyrin and cisplatin and explored whether they exerted negative effects on molecular structure of cisplatin as well as its antitumor efficacy. Method(1) Free radical production was determined by starch-KI method in the presence of microbubble,haematoporphyrin and cisplatin in HIFU.(2) MTT was used to detect survival rate of human ovarian cancer cell line HO8910 with cisplatin after the interaction;HPLC was used simultaneously to observe whether there was any molecular alteration or not.Result(1) Except DDP US60s group,other treatment groups receiving radiation for 60 second-HP US60s,Microbubble US60s,DDP+HP US60s, DDP+Microbubble US60s,DDP+HP+Microbubble US60s have relatively higher UV absorbance than the control group US60s in 555nm(P＜0.05,P＜0.05,P＜0.05,P＜0.05,P＜0.05,P＜0.05),indicating interaction between cisplatin,microbubble,haematoporphyrin in HIFU could create large mounts of free radicals which was similar in these treatment groups receiving radiation for 120 second.With prolonged radiation duration, radicals production increased:DDP+HP+Microbubble US120s brought about significantly larger mounts of radicals than DDP+HP+Microbubble US60s group(P＜0.05).(2) In 72h treatment groups,there was no statistical differences of cell inhibition rate in DDP group,DDP+US60s group and DDP+US120s group(P＞0.05,P＞0.05),DDP+Hp group, DDP+Hp+US60s group and DDP+Hp+US120s group(P＞0.05,P＞0.05), DDP+Microbubble group,DDP+Microbubble+US60s group and DDP+ Microbubble+US120s group(P＞0.05,P＞0.05) respectively,neither in DDP+Hp+Microbubble group,DDP+Hp+Microbubble+US60s group and DDP+Hp+Microbubble+US120s group(P＞0.05,P＞0.05).We conducted molecular structure analysis of cisplatin by HPLC and observed no obvious peak area ratio differences among these groups.ConclusionHaematoporphyrin and contrast agents could enhance ultrasonic cavitation,but neither impair the potency of cisplatin under high intensity ultrasound field.