Yang Yunshan, Chen Yinghu, Zhang Fanghui, Zhao Qiyu, Zhong Haijun
Department of Chemotherapy, Zhejiang Cancer Hospital , Hangzhou .
Int J Hyperthermia. 2015;31(5):498-506. doi: 10.3109/02656736.2015.1036384. Epub 2015 May 8.
Tumour-cell-derived exosomes (Exo) have been proposed as a new kind of drug carrier, and heat stress can promote release of exosomes from tumour cells. This study investigated the impact of heat stress on the quantity of doxorubicin in exosomes from the same number of doxorubicin-treated MFC-7 tumour cells and their anti-tumour effects.
Exosomes were isolated from phosphate-buffered saline (Exo), doxorubicin (Exo-Dox) or doxorubicin combined with heat-stress-treated (Exo-Dox-HS) MCF-7 cells. The content of doxorubicin in the exosomes was determined by flow cytometry. The effects of individual types of exosomes on the MCF-7 cell proliferation and apoptosis as well as the tumour growth were determined by MTT assay, flow cytometry and murine xenograft tumour modelling.
We found that the amount of Exo-Dox-HS was higher than that of Exo-Dox from the same number of MCF-7 cells, and Exo-Dox-HS contained higher levels of doxorubicin than Exo-Dox from the same number of cells. Exo-Dox and Exo-Dox-HS, but not Exo or 10 µg/mL doxorubicin, significantly inhibited the MCF-7 cell proliferation and triggered MCF-7 cell apoptosis, associated with increased levels of cleaved caspase-3 and -8 and morphological changes in MCF-7 cells. Treatment with Exo-Dox and Exo-Dox-HS inhibited the growth of implanted breast tumours in mice.
Our study indicated that heat stress increased the quantity of doxorubicin-containing exosomes from tumour cells, and enhanced the anti-tumour effect of exosomes from the doxorubicin-treated tumour cells. Our findings may aid in designing new strategies for cancer therapy by combination of chemotherapy and hyperthermia.
肿瘤细胞衍生的外泌体（Exo）已被提议作为一种新型药物载体，热应激可促进肿瘤细胞释放外泌体。本研究调查了热应激对相同数量阿霉素处理的MFC - 7肿瘤细胞来源的外泌体中阿霉素含量及其抗肿瘤作用的影响。
从磷酸盐缓冲盐水（Exo）、阿霉素（Exo - Dox）或阿霉素联合热应激处理（Exo - Dox - HS）的MCF - 7细胞中分离外泌体。通过流式细胞术测定外泌体中阿霉素的含量。通过MTT法、流式细胞术和小鼠异种移植肿瘤模型确定不同类型外泌体对MCF - 7细胞增殖、凋亡以及肿瘤生长的影响。
我们发现，相同数量的MCF - 7细胞来源的Exo - Dox - HS的量高于Exo - Dox，并且相同数量细胞来源的Exo - Dox - HS所含阿霉素水平高于Exo - Dox。Exo - Dox和Exo - Dox - HS，而非Exo或10μg/mL阿霉素，显著抑制MCF - 7细胞增殖并引发MCF - 7细胞凋亡，这与裂解的caspase - 3和 - 8水平升高以及MCF - 7细胞形态变化有关。Exo - Dox和Exo - Dox - HS处理可抑制小鼠体内植入的乳腺肿瘤生长。
我们的研究表明，热应激增加了肿瘤细胞来源的含阿霉素外泌体的数量，并增强了阿霉素处理的肿瘤细胞来源的外泌体的抗肿瘤作用。我们的发现可能有助于通过化疗与热疗相结合来设计新的癌症治疗策略。
