Wu Meng, Wang Ying, Wang Yiru, Zhang Mingbo, Luo Yukun, Tang Jie, Wang Zhigang, Wang Dong, Hao Lan, Wang Zhibiao
School of Medicine, Nankai University, Tianjin.
Department of Ultrasound, Chinese PLA General Hospital, Beijing.
Int J Nanomedicine. 2017 Jul 26;12:5313-5330. doi: 10.2147/IJN.S136032. eCollection 2017.
In the current study, we synthesized prostate cancer-targeting poly(lactide--glycolic acid) (PLGA) nanobubbles (NBs) modified using A10-3.2 aptamers targeted to prostate-specific membrane antigen (PSMA) and encapsulated paclitaxel (PTX). We also investigated their impact on ultrasound (US) imaging and therapy of prostate cancer. PTX-A10-3.2-PLGA NBs were developed using water-in-oil-in-water (water/oil/water) double emulsion and carbodiimide chemistry approaches. Fluorescence imaging together with flow cytometry verified that the PTX-A10-3.2-PLGA NBs were successfully fabricated and could specifically bond to PSMA-positive LNCaP cells. We speculated that, in vivo, the PTX-A10-3.2-PLGA NBs would travel for a long time, efficiently aim at prostate cancer cells, and sustainably release the loaded PTX due to the improved permeability together with the retention impact and US-triggered drug delivery. The results demonstrated that the combination of PTX-A10-3.2-PLGA NBs with low-frequency US achieved high drug release, a low 50% inhibition concentration, and significant cell apoptosis in vitro. For mouse prostate tumor xenografts, the use of PTX-A10-3.2-PLGA NBs along with low-frequency US achieved the highest tumor inhibition rate, prolonging the survival of tumor-bearing nude mice without obvious systemic toxicity. Moreover, LNCaP xenografts in mice were utilized to observe modifications in the parameters of PTX-A10-3.2-PLGA and PTX-PLGA NBs in the contrast mode and the allocation of fluorescence-labeled PTX-A10-3.2-PLGA and PTX-PLGA NBs in live small animals and laser confocal scanning microscopy fluorescence imaging. These results demonstrated that PTX-A10-3.2-PLGA NBs showed high gray-scale intensity and aggregation ability and showed a notable signal intensity in contrast mode as well as aggregation ability in fluorescence imaging. In conclusion, we successfully developed an A10-3.2 aptamer and loaded PTX-PLGA multifunctional theranostic agent for the purpose of obtaining US images of prostate cancer and providing low-frequency US-triggered therapy of prostate cancer that was likely to constitute a strategy for both prostate cancer imaging and chemotherapy.
在本研究中，我们合成了靶向前列腺癌的聚乳酸-乙醇酸共聚物（PLGA）纳米气泡（NBs），其用靶向前列腺特异性膜抗原（PSMA）的A10-3.2适配体修饰并包裹了紫杉醇（PTX）。我们还研究了它们对前列腺癌超声（US）成像和治疗的影响。PTX-A10-3.2-PLGA NBs采用水包油包水（水/油/水）双乳液和碳二亚胺化学方法制备。荧光成像结合流式细胞术证实PTX-A10-3.2-PLGA NBs成功制备，并且能够特异性结合PSMA阳性的LNCaP细胞。我们推测，在体内，PTX-A10-3.2-PLGA NBs将长时间循环，有效靶向前列腺癌细胞，并由于增强的通透性、滞留效应和超声触发的药物递送而持续释放负载的PTX。结果表明，PTX-A10-3.2-PLGA NBs与低频超声联合使用在体外实现了高药物释放、低50%抑制浓度和显著的细胞凋亡。对于小鼠前列腺肿瘤异种移植模型，使用PTX-A10-3.2-PLGA NBs联合低频超声实现了最高的肿瘤抑制率，延长了荷瘤裸鼠的生存期，且无明显全身毒性。此外，利用小鼠LNCaP异种移植模型观察了PTX-A10-3.2-PLGA和PTX-PLGA NBs在造影模式下的参数变化以及荧光标记的PTX-A10-3.2-PLGA和PTX-PLGA NBs在活体小动物体内的分布情况，并进行激光共聚焦扫描显微镜荧光成像。这些结果表明PTX-A10-3.2-PLGA NBs显示出高灰度强度和聚集能力，在造影模式下显示出显著的信号强度，在荧光成像中也显示出聚集能力。总之，我们成功开发了一种A10-3.2适配体负载PTX的PLGA多功能诊疗试剂，用于获取前列腺癌的超声图像并提供低频超声触发的前列腺癌治疗，这可能构成一种前列腺癌成像和化疗的策略。
