外泌体转移的 p-STAT3 促进结直肠癌细胞获得对 5-FU 的耐药性。
Exosomal transfer of p-STAT3 promotes acquired 5-FU resistance in colorectal cancer cells.
机构信息
Guangdong Institute of Gastroenterology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, Guangdong, China.
Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510655, Guangdong, China.
出版信息
J Exp Clin Cancer Res. 2019 Jul 19;38(1):320. doi: 10.1186/s13046-019-1314-9.
BACKGROUND
Acquired resistance remains a limitation of the clinical use of 5-fluorouracil (5-FU). Because exosomes, are important vesicles participating in intercellular communication, their contribution to the development of acquired 5-FU resistance needs to be elucidated. In this study, we aimed to examine the underlying mechanisms of exosomes from 5-FU resistant cells (RKO/R) in sustaining acquired 5-FU resistance in sensitive cells (RKO/P).
METHODS
Exosomes from a 5-FU-resistant cell line (RKO/R) and its parental cell line RKO/P were isolated and co-cultured with 5-FU-sensitive cells. Real-time cellular analysis (RTCA) and FACS analysis were used to examine cell viability and apoptosis. Exosomal protein profiling was performed using shotgun proteomics. Inhibitors and siRNAs were applied to study the involvement of selected proteins in 5-FU resistance. The effect of exosomal p-STAT3 (Tyr705) on the caspase cascade was examined by western blotting (WB) and high content analysis. Xenograft models were established to determine whether exosomal p-STAT3 can induce 5-FU resistance in vivo.
RESULTS
Our results indicated that exosomes from RKO/R cells significantly promoted cell survival during 5-FU treatment. Proteomics and WB analysis results indicated that GSTP1 and p-STAT3 (Tyr705) were enriched in exosomes from RKO/R cells. Inhibition of p-STAT3 re-sensitized RKO/P cells to 5-FU via caspase cascade. Furthermore, p-STAT3 packaged by exosomes from RKO/R cells increased resistance of tumor cells to 5-FU in vivo.
CONCLUSIONS
Our results reveal a novel mechanism by which p-STAT3-containing exosomes contribute to acquired 5-FU resistance in CRC. This study suggests a new option for potentiating the 5-FU response and finding biomarkers for chemotherapy resistance.
背景
获得性耐药仍然是氟尿嘧啶（5-FU）临床应用的一个限制。由于外泌体是参与细胞间通讯的重要小泡，因此需要阐明它们对获得性 5-FU 耐药性发展的贡献。在这项研究中，我们旨在研究来自 5-FU 耐药细胞（RKO/R）的外泌体在维持敏感细胞（RKO/P）获得性 5-FU 耐药中的潜在机制。
方法
从 5-FU 耐药细胞系（RKO/R）及其亲本细胞系 RKO/P 中分离出外泌体，并与 5-FU 敏感细胞共培养。实时细胞分析（RTCA）和 FACS 分析用于检测细胞活力和细胞凋亡。使用鸟枪法蛋白质组学进行外泌体蛋白谱分析。应用抑制剂和 siRNA 研究选定蛋白质在 5-FU 耐药中的作用。通过 Western blot（WB）和高内涵分析研究外泌体 p-STAT3（Tyr705）对胱天蛋白酶级联的影响。建立异种移植模型以确定外泌体 p-STAT3 是否可以在体内诱导 5-FU 耐药。
结果
我们的结果表明，来自 RKO/R 细胞的外泌体在 5-FU 治疗期间显著促进了细胞存活。蛋白质组学和 WB 分析结果表明，GSTP1 和 p-STAT3（Tyr705）在 RKO/R 细胞的外泌体中富集。抑制 p-STAT3 通过胱天蛋白酶级联使 RKO/P 细胞对 5-FU 重新敏感。此外，来自 RKO/R 细胞的外泌体包装的 p-STAT3 增加了肿瘤细胞对体内 5-FU 的耐药性。
结论
我们的结果揭示了 p-STAT3 包含的外泌体促进 CRC 获得性 5-FU 耐药的新机制。这项研究为增强 5-FU 反应和寻找化疗耐药的生物标志物提供了新的选择。
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