High-intensity focused ultrasound induced apoptosis with caspase 3, 8, and 9/6 activation in rat hepatoma
High-intensity focused ultrasound induced apoptosis with caspase 3, 8, and 9/6 activation in rat hepatoma
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DOI：
10.1007/s10396-009-0234-2
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发表时间：
2009-09
影响因子：
1.8
通讯作者：
N. Hirokawa;K. Koito;F. Okada;N. Kudo;Katsuyuki Yamamoto;K. Fujimoto;M. Nishida;T. Ichimura;M. Hori;T. Satoh;M. Hareyama
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文献类型：
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作者：
N. Hirokawa;K. Koito;F. Okada;N. Kudo;Katsuyuki Yamamoto;K. Fujimoto;M. Nishida;T. Ichimura;M. Hori;T. Satoh;M. Hareyama
本研究旨在探讨高强度聚焦超声(HIFU)在不同照射条件下的抗癌效果及半胱氨酸天冬氨酸氨基转移酶(Caspase)证实的细胞凋亡情况。用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记法(TUNEL)和Hoechst 33258染色检测细胞凋亡，并分别检测caspase 3、8和9/6的活性。结果HIFU可使KDH8皮下肿瘤缩小，存活时间延长(P<；P<0.01)。对于肿瘤控制和长期生存，高强度聚焦超声能量的最低阈值为30W×10W。高强度聚焦超声照射的肿瘤细胞在低于10W×1.0W的S照射条件下表现出明显的凋亡特征，而在培养的KDH8细胞中，低于30W的照射可诱导细胞发生凋亡(P<；P<；0.01)，且随着能量的降低诱导更多的细胞凋亡。Caspase 3、8和9/6在低能条件下被激活(P<；P<；0.01)。Caspase A3、8和9/6在低能条件下被激活(P<；P<；0.01)，且Caspase A3、8和9/6的激活程度明显高于Caspase A9/6(P<；0.01)。结论HIFU在体内和体外诱导肿瘤细胞凋亡是HIFU诱导肿瘤的机制之一，并由Caspase A3、Caspase 8和Caspase 9/6介导，Caspase A8的激活程度明显高于Caspase A9/6，提示HIFU诱导的细胞凋亡途径可能更依赖于线粒体。然而，还需要进一步的检查。
PurposeThe purpose of the present study is to investigate anticancer efficacy and apoptosis confirmed by caspase under several exposure conditions of high-intensity focused ultrasound (HIFU).Materials and methodsTwenty-five rats with KDH-8 hepatoma were treated by HIFU at several acoustic energies to evaluate treatment efficacy. Apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and Hoechst 33258 staining, and caspase 3, 8, and 9/6 activity was respectively assayed.ResultsThe KDH-8 subcutaneous tumors were reduced by HIFU, and these rats survived longer than the nontreatment rats (P< 0.01). The minimal threshold of HIFU energy was 30 W × 1.0 s for tumor control and long-term survival. The tumors exposed to HIFU exhibited marked apoptotic features under conditions of less than 10 W × 1.0 s. In cultured KDH-8 cells, apoptosis was caused at less than 30 W × 1.0 s (P< 0.01), and more was induced as the energy went down. Caspase 3, 8, and 9/6 were more activated at low energy under 10 W × 1.0 s (P< 0.01), and caspase 8, which is death receptor dependent, was significantly more activated than caspase 9/6, which is mitochondria dependent (P< 0.01).ConclusionHIFU-induced apoptosis in vivo and in vitro is one of the mechanisms for tumor control and is mediated by caspase 3, 8, and 9/6. The significantly greater activation of caspase 8 than of caspase 9/6 suggests that the apoptosis pathway induced by HIFU might be more mitochondria dependent than death receptor dependent. However, further examination will be needed.