Emam Sherif E, Ando Hidenori, Abu Lila Amr Selim, Kobayashi Shinya, Shimizu Taro, Okuhira Keiichiro, Ishima Yu, Ishida Tatsuhiro
Department of Pharmacokinetics and Biopharmaceutics, Institute of Biomedical Sciences, Tokushima University.
Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Zagazig University.
Biol Pharm Bull. 2018;41(7):1078-1083. doi: 10.1248/bpb.b18-00202.
Modulation of tumor immunity is a known factor in the antitumor activity of many chemotherapeutic agents. Exosomes are extracellular nanometric vesicles that are released by almost all types of cells, which includes cancer cells. These vesicles play a crucial role in tumor immunity. Many in vitro studies have reproduced the aggressive secretion of exosomes following treatment with conventional anticancer drugs. Nevertheless, how chemotherapeutic agents including nanomedicines such as Doxil affect the in vivo secretion of exosomes is yet to be elucidated. In this study, the effect of intravenous injection of either free doxorubicin (DXR) or liposomal DXR formulation (Doxil) on exosome secretion was evaluated in BALB/c mice. Exosomes were isolated from serum by using an ExoQuick™ kit. Free DXR treatment markedly increased serum exosome levels in a post-injection time-dependent manner, while Doxil treatment did not. Exosomal size distribution and marker protein expressions (CD9, CD63, and TSG101) were studied. The physical/biological characteristics of treatment-induced exosomes were comparable to those of control mice. Interestingly, splenectomy significantly suppressed the copious exosomal secretions induced by free DXR. Collectively, our results indicate that conventional anticancer agents induce the secretion of circulating exosomes, presumably via stimulating immune cells of the spleen. As far as we know, this study represents the first report indicating that conventional chemotherapeutics may induce exosome secretion which might, in turn, contribute partly to the antitumor effect of chemotherapeutic agents.
肿瘤免疫调节是许多化疗药物抗肿瘤活性的一个已知因素。外泌体是几乎所有类型细胞（包括癌细胞）释放的细胞外纳米级囊泡。这些囊泡在肿瘤免疫中起关键作用。许多体外研究已重现了用传统抗癌药物处理后外泌体的大量分泌。然而，包括多柔比星脂质体（如多西紫杉醇）在内的化疗药物如何影响外泌体的体内分泌尚待阐明。在本研究中，评估了静脉注射游离多柔比星（DXR）或多柔比星脂质体制剂（多西紫杉醇）对BALB/c小鼠外泌体分泌的影响。使用ExoQuick™试剂盒从血清中分离外泌体。游离DXR处理后血清外泌体水平呈注射后时间依赖性显著增加，而多西紫杉醇处理则没有。研究了外泌体大小分布和标记蛋白表达（CD9、CD63和TSG101）。处理诱导的外泌体的物理/生物学特性与对照小鼠的相当。有趣的是，脾切除术显著抑制了游离DXR诱导的大量外泌体分泌。总体而言，我们的结果表明，传统抗癌药物可能通过刺激脾脏免疫细胞诱导循环外泌体的分泌。据我们所知，本研究是首次表明传统化疗药物可能诱导外泌体分泌，这反过来可能部分有助于化疗药物的抗肿瘤作用的报告。
