Radiolysis, Photolysis and Sonolysis of Cells

工作概述：声动力疗法是一种很有前景的新型癌症治疗方式，它基于声敏器和超声联合杀伤细胞的协同作用。超声波可以深入组织，并可以聚焦在肿瘤的一个小区域，以激活无毒分子（如卟啉），从而最大限度地减少不良的副作用。实验证据表明，声敏化是由于在热坍缩空化泡内部或附近的声敏化剂被化学激活，通过在水气界面直接热解敏化剂或通过水的热解形成氢原子和羟基自由基的反应而形成敏化剂衍生自由基。来自声敏剂的自由基（主要以碳为中心）与氧反应形成过氧基和烷氧基自由基。与在空化泡内通过热解形成的OH自由基和H原子不同，烷氧基和过氧基自由基在生物介质中与有机化合物的反应活性要低得多，因此它们到达细胞关键部位的可能性更高。研究了超声（47 kHz）和卟啉镓衍生物类似物（ATX-70）对悬浮在细胞培养基中的人白血病细胞HL-525和HL-60的协同溶解作用。有机表面活性剂优先在空化泡的气/液界面积聚并分解，产生二次自由基，并扩散到体溶液中。本研究中使用的卟啉镓类似物具有两个n-烷基侧链（ATX-Cx，其中x =碳原子数，范围从x = 2到x = 12）。通过改变正烷基链长，从而改变ATX-Cx衍生物的表面活性剂性质，确定了与ATX-Cx衍生物在气/液界面上积聚有关的细胞杀伤。在ATX-Cx存在下进行声溶后，观察到碳中心自由基的产率与细胞杀伤有很强的相关性。这些结果支持了超声和ATX-Cx对HL-525和HL-60细胞的协同作用的声化学机制的假设。超声诱导U937细胞凋亡和低渗培养基裂解的研究支持非致死性低渗可以增强超声诱导的细胞杀伤的假设。偶氮双氯化物（2-氨基丙烷）对超声诱导的U937细胞杀伤有增强作用。这些发现提示温度依赖性自由基发生器在超声治疗癌症中的临床潜力。声动力治疗的机制可能没有一个通用的机制，而可能受到多种因素的影响，包括生物模型的性质、声敏剂和超声参数。小川,r;近藤,t;森h;赵,Q.L.;福田,美国;溶解气体对超声介导的体外基因转染的影响。超声与超声化学，9,197-203,2002.2。Feril第2;近藤,t;Umemura,美国;立花,k;Manalo A.H.;声波和抗肿瘤药物：一种增强联合抗癌治疗的可能性。已婚顾客。超声（日本），29,173-187,2002.3。Sostaric， J.Z.和Riesz， P.：空化气泡气/液界面表面活性剂的吸附：超声化学中超声强度无关频率效应。期刊。化学。[j] .中国生物医学工程学报，2009,31(2):537- 548。三好:;Sostaric J.Z.;表面活性剂溶液的声化学与用超声波和卟啉杀死人白血病细胞的关系。免费Rad. Biol。医学杂志，34,710-719,2003。

Summary of work:Sonodynamic therapy is a promising new modality for cancer treatment based on the synergistic effects of cell killing by a combination of sonosensitzer and ultrasound. Ultrasound can penetrate deeply into tissue and can be focused in a small region of tumor to activate non-toxic molecules (e.g. porphyrins ) thus minimizing undesirable side effects. The experimental evidence suggests that sonosensitization is due to the chemical activation of sonosensitizers inside or in close vicinity of hot collapsing cavitation bubbles to form sensitizer-derived radicals either by direct pyrolysis of the sensitizer at the water-gas interface or due to the reactions of hydrogen atoms and hydroxyl radicals formed by the pyrolysis of water. The free radicals derived from the sonosensitizer (mostly carbon-centered) react with oxygen to form peroxyl and alkoxyl radicals. Unlike OH radicals and H atoms which are formed by pyrolysis inside cavitation bubbles, the reactivity of alkoxyl and peroxyl radicals with organic compounds in biological media is much lower and hence they have a higher probability of reaching critical cellular sites.The synergistic effect of ultrasound (47 kHz) and analogues of gallium-porphyrin derivatives (ATX-70) on cytolysis of human leukemia cells (HL-525 and HL-60) suspended in a cell culture medium were studied. Organic surfactants preferentially accumulate and subsequently decompose at the gas/solution interface of cavitation bubble, producing secondary radicals that can diffuse to the bulk solution. The gallium porphyrin analogues used in the current study possessed two n-alkyl side chains (ATX-Cx, where x = number of carbon atoms, ranging from x = 2 to x = 12). By varying the n-alkyl chain length, thereby modifying the surfactant properties of the ATX-Cx derivatives, cell killing in relation to the accumulation of the ATX-Cx derivatives at the gas/solution interface of cavitation bubbles was determined. Following sonolysis in the presence of the ATX-Cx, a strong correlation for the yield of carbon centered radicals and cell killing was observed. These results support the hypothesis that a sonochemical mechanism is responsible for the synergistic effect of ultrasound and ATX-Cx on HL-525 and HL-60 cells. Studies of the ultrasound-induced apoptosis and lysis of U937 cells by a hypotonic medium support the hypothesis that non-lethal hypotonia can enhance ultrasound-induced cell-killing. Ultrasound-induced killing of U937 cells was enhanced by azobis(2-amidinopropane)dihydrochloride. These findings suggest the clinical potential of temperature-dependent free radical generators in cancer therapy by ultrasound. The mechanism of sonodynamic therapy is probably not governed by a universal mechanism, but may be influenced by multiple factors including the nature of the biological model, the sonosensitizer and the ultrasound prameters.1.Ogawa, R.; Kondo, T.; Mori, H.; Zhao, Q.L.; Fukuda, S.; Riesz, P.: Effects of dissolved gases on ultrasound mediated in vitro gene transfection. Ultrasonics Sonochemistry, 9, 197-203, 2002.2.Feril, L.B.; Kondo, T.; Umemura, S.; Tachibana, K.; Manalo, A.H.; Riesz, P.: Sound waves and antineoplastic drugs: The possibility of an enhanced combined anticancer therapy. J.Med.Ultrasonics(Japan), 29, 173-187, 2002.3.Sostaric, J.Z. and Riesz, P.: Adsorption of surfactants at the gas/solution interface of cavitation bubbles: An ultrasound intensity independent frequency effect in sonochemistry. J. Phys. Chem. B., 106, 12537-12548, 2002.4.Miyoshi, N.; Sostaric, J.Z.; Riesz, P.: Correlation between sonochemistry of surfactant solutions and human leukemia cell killing by ultrasound and porphyrins. Free Rad. Biol. Med., 34, 710-719, 2003.