Effect Of Sonodynamic Therapy On Plasma Membrane Structure And Function Of Ascites S180 Tumor Cell

At present, tumor is one of the mainly vital diseases threatening people's health though the investigations of antitumor have been carrying on hundreds years. Tumor becomes the second killer in West and China except for coronary heart disease and cardiovascular disease but is the primacy for mortality. There are lots of antitumor therapies in recent years as actinotheraphy, chemotherapeutics, surgical, and ultrasound is paied more and more attention since it has obvious biologic effect in antitumor. Applications of ultrasound refer to high intensity focus ultrasound therapy, heat therapy and sonodynamic therapy. Sonodynamic Therapy (SDT) is a new anti-tumor therapy brought forward by Japanese scholars Umemura et al in 1989 to kill cancer cells by synergistic effects of ultrasound (US) and hematoporphyrin (HpD). This therapy isbased on the US that can penetrate deep into the tissue and activate HpD which wasaccumulated in tumor. Because of possessing excellent pertinency, penetration abilityand no wound for normal tissues, the therapy has advantages for curing deep cancers. From then on, Scholars have been investigating this therapy for decades extensively and deeply, including the mechanism such as cayatition, singlet oxygen, hydroxide radicals, alkyl oxygen radicals, choice of sonosensitizer such as antitumor drug, porphyrin, and other compounds, morphologic changes after SDT treatment showing there are tow effect models: necrosis and apoptosis, and other histochemistry studies. But for the biologic approaches and mechanism that SDT inhibits tumor growth and induces tumor apoptosis, it is lack of investigation and only a few studies indicate that SDT can initiate plasma membrane Lipid peroxidation to arouse cell damage. It is short of study about integral proteins which are close to cell proliferation and apoptosis.In this dissertation, 1.8MHz, 2W/cm~2 is used to study the effect of sonodynamic therapy on plasma membrane structure and function of ascites S180 tumor cell on the background of international research development and our previous results and this r-esearch is supported by national natural science foundation of China, graduate student innovation foundation of shaanxi normal university, student innovation foundation of college of life sciences. Presently, the results got as follow: 1. Effect on integral proteins: EGFR, Ras, Fas, FasL exhibited intensive positivelabeling on SI80 cells in CT and H groups with no changes as time goes on using a polyclonal antibody against aim protein to label proteins expression;In US groups, EGFR, Fas, FasL showed decrease expression at lhr, 3hrs, 5hrs after ultrasound treatment besides Ras with no changes;Markedly reduced expression were observed in UH groups at lhr (PO.01) with different decline degree. At 3hrs and 5hrs, EGFR, Ras and FasL decreased continually whereas Fas retained at certain level. Fujimoto's plumbi nitrate detect enzyme activity. As the same, activity of Adenylate cyclase and Guanylate cyclase showed significant decrease after ultrasound-activated hematoporphyrin treatment with prolonging time in UH groups (PO.01) whereas CT, H groups had no changes and US groups declined little. UH groups had better inhibition effect than US groups and HpD alone had no effect. These results indicate that SDT enhances the effect of single ultrasound evidently, restrains the expression of integral proteins and the activity of enzyme. The mechanism of SDT inhibiting tumor growth are: blocking growth signal pathway made up by EGFR and Ras to slow down tumor proliferation, inactivating Adenylate cyclase and Guanylate cyclase to disturb metabolism, reducing FasL expression to abate immunity escape of tumor cells thereby cancer will be destroyed by immunity cells in body, and Fas may initiates apoptosis to inhibit cancer.2. Effect on lipid: TBA detection, colorimetry and fluorescence polarization were used for lipid peroxidation, free fatty acid concentration and membrane fluidity studies. Ultrasound alone could initiate lipid peroxidation and lecithoid configuration degradation resulting in membrane fluidity decline. Ultrasound combined with HpD could enhance ultrasonic efficiency obviously. HpD alone had no effect. After SDT treated, the negative correlation between membrane fluidity declining and lipid peroxidation, lecithoid configuration degradation was seen, and lecithoid configuration degradation may play an important role. According to the results, SDT can elevate the degree of lipid peroxidation, enhance lecithoid configuration degradation evidently to drop the membrane fluidity, consequently, the membrane function is impacted and tumor growth was inhibited availably.3. Inducement of tumor cell apoptosis: Fas and FasL exhibited intensive positive labeling on SI80 cells. Reduced expression was observed in UH group after lh and 3h when treatment of ultrasound plus hematoporphyrin finished. After 5h, FasL decreased continually whereas Fas retaiiied at high level. Caspase-8 showed significant expression after lh when treatment completed while caspase-3 had no obvious change and arrivedIVat peak at same time after 3h then reduced together. AV-PI double stain elucidate that there were plenty of apoptosis cells observed after lh, and cells enter terminal apoptosis after 3h in UH group whereas part cells began apoptosis after 3h in U group. CT and H group are nearly no stained. Fas/FasL system has important function in SDT. Fas may initiate apoptosis induced by SDT and reduced FasL restrain the immunity escape of tumor cells. As consequences, tumor cells can be destroyed by immunity cells in body.