Ultrasound and microbubbles can induce apoptosis of tumor cells. However, the effects of ultrasound and microbubbles (USMB) combined with chemotherapy on in vivo tumors have rarely been studied. This research is to evaluate the efficacy of targeted USMB and chemotherapeutic drugs on apoptosis and inhibition of hepatic carcinoma cells in nude mice. We also summarize case reports of its clinical application. It was divided into three parts: First, the subcutaneous hepatic tumors of nude mice were irradiated with ultrasound (20 kHz, 2 W/cm², 40% duty cycle) and SonoVue microbubbles injected to the tail vein of the mice followed by chemotherapy comprising cisplatin, mitomycin, and 5-fluorouracil. The apoptosis of hepatoma cells was examined by TUNEL staining, and the expression of the Bax and Bcl-2 proteins in the tumor tissues was detected by immunohistochemistry. The microvasculature of the tumor tissues was observed by transmission electron microscope. Second, orthotopic hepatic tumors in nude mice were irradiated by USMB and chemotherapy. The therapeutic effects were evaluated by magnetic resonance imaging. Third, the malignant tumors in three patients were treated with USMB and chemotherapy. Our results showed that microbubbles focused by low-frequency US ruptured microvessel walls, through which more chemotherapy drugs entered into the carcinoma cells, thus enhancing cell apoptosis, increasing Bax protein expression, and decreasing Bcl-2 expression. The survival period of the nude mice in the USMB and chemotherapy group was the longest, compared with the control, USMB, and chemotherapy (χ²=29.37, P < 0.0001). Magnetic resonance imaging examinations revealed the tumor volumes in nude mice decreased after USMB and chemotherapy (t = 3.91, P = 0.0173). In clinical cases, after USMB and chemotherapy, the diameters of tumors decreased and the symptoms of the patients were relieved. Targeted low-frequency ultrasound combined with chemotherapy can promote tumor cell apoptosis, inhibit tumor growth, and relieve clinical symptoms of patients.

Impact statement

The novelty of this research is that we used ultrasound cavitation to enhance the effects of chemotherapy in the subcutaneous and orthotopic hepatic carcinomas in nude mice. Case reports of the effects of the targeting ultrasound cavitation and chemotherapy on malignant tumors in clinical patients were also examined. We found that low-frequency ultrasound cavitation combined with chemotherapy is effective in the inhibition of tumor growth to some extent.

中文翻译：

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超声空化增强化疗：体内研究和临床应用。

超声和微泡可诱导肿瘤细胞凋亡。然而，超声和微泡（USMB）联合化疗对体内肿瘤的影响却鲜有研究。本研究旨在评估靶向USMB和化疗药物对裸鼠肝癌细胞凋亡和抑制的疗效。我们还总结了其临床应用的病例报告。分为三部分：首先，对裸鼠皮下肝肿瘤进行超声（20 kHz，2 W/cm ²，40% 占空比）和 SonoVue 微泡注射到小鼠的尾静脉，然后进行包含顺铂、丝裂霉素和 5-氟尿嘧啶的化疗。TUNEL染色检测肝癌细胞凋亡情况，免疫组化检测肿瘤组织中Bax和Bcl-2蛋白的表达。通过透射电子显微镜观察肿瘤组织的微血管系统。其次，通过USMB和化学疗法照射裸鼠的原位肝肿瘤。通过磁共振成像评估治疗效果。第三，3例患者恶性肿瘤均采用USMB联合化疗。我们的结果表明，低频US聚焦的微泡破裂了微血管壁，更多的化疗药物通过微血管壁进入癌细胞，从而增强细胞凋亡，增加 Bax 蛋白表达，降低 Bcl-2 表达。与对照组、USMB和化疗组相比，USMB组和化疗组裸鼠存活时间最长（χ² = 29.37，P  < 0.0001）。磁共振成像检查显示，USMB 和化疗后裸鼠的肿瘤体积减少（t = 3.91，P  = 0.0173）。在临床病例中，经USMB和化疗后，肿瘤直径缩小，患者症状减轻。靶向低频超声联合化疗可促进肿瘤细胞凋亡，抑制肿瘤生长，缓解患者临床症状。

影响陈述

这项研究的新颖之处在于我们使用超声空化来增强化疗对裸鼠皮下和原位肝癌的影响。还检查了靶向超声空化和化疗对临床患者恶性肿瘤的影响的病例报告。我们发现低频超声空化联合化疗在一定程度上有效抑制肿瘤生长。