miR-567-PIK3AP1-PI3K/AKT-c-Myc 反馈环路调节胃癌的肿瘤生长和化疗耐药性。

A miR-567-PIK3AP1-PI3K/AKT-c-Myc feedback loop regulates tumour growth and chemoresistance in gastric cancer.

机构信息

Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.

Department of General Surgery, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, China.

出版信息

EBioMedicine. 2019 Jun;44:311-321. doi: 10.1016/j.ebiom.2019.05.003. Epub 2019 May 9.

DOI:10.1016/j.ebiom.2019.05.003

PMID:31078520

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6603849/

Abstract

BACKGROUND

Gastric cancer (GC) ranks the fifth most common cancer, and chemotherapy is one of the most common treatments for GC. However, chemoresistance limits the effectiveness of chemotherapy and leads to treatment failure. This study aims to investigate the biological effect of miR-567 on gastric tumourigenesis and chemoresistance and reveal the possible mechanism.

METHODS

We measured the expression of miR-567 in 37 paired normal and stomach tumour specimens, as well as GC cell lines by Real-time PCR. The functional effects of miR-567 were validated using in vitro and in vivo assays. Dual-luciferase report assays and Chromatin immunoprecipitation (ChIP) assay were conducted for target evaluation, western blot assay was used to confirm the relationships.

FINDINGS

Our data showed that miR-567 was downregulated in gastric tissues and gastric cancer cells compared with normal tissues and gastric epithelial cells. In vitro, Gain- and lose-of-function assays showed miR-567 not only weakened cells proliferative ability, but also sensitized GC cells to 5-FU and oxaliplatin. In vivo, miR-567 overexpression significantly repressed the tumourigenesis of GC cells compared with the vector control. Mechanistic analysis showed that PIK3AP1 activated AKT phosphorylation in GC. Meanwhile, miR-567 directly targeted PIK3AP1 to inactivate PI3K/AKT/c-Myc pathway and c-Myc inversely regulated miR-567 expression, thus forming a miR-567-PIK3AP1- PI3K/AKT-c-Myc feedback loop explaining the function of miR-567.

INTERPRETATION

Our studies revealed that miR-567 acts as a tumour suppressor gene and suppresses GC tumorigenesis and chemoresistance via a miR-567-PIK3AP1- PI3K/AKT-c-Myc feedback loop. These results suggest that miR-567 may serve as a target for chemoresistance and a potential prognostic biomarker for GC.

摘要

背景

胃癌（GC）是第五大常见癌症，化疗是 GC 的最常见治疗方法之一。然而，化疗耐药限制了化疗的有效性并导致治疗失败。本研究旨在探讨 miR-567 对胃癌发生和化疗耐药的生物学影响，并揭示可能的机制。

方法

我们通过实时 PCR 测量了 37 对正常和胃肿瘤标本以及 GC 细胞系中 miR-567 的表达。通过体外和体内实验验证了 miR-567 的功能效应。进行双荧光素酶报告实验和染色质免疫沉淀（ChIP）实验以评估靶标，并用 Western blot 实验验证了这些关系。

发现

我们的数据表明，与正常组织和胃上皮细胞相比，miR-567 在胃组织和胃癌细胞中下调。体外实验中，Gain 和 Loss of Function 实验表明，miR-567 不仅削弱了细胞的增殖能力，还使 GC 细胞对 5-FU 和奥沙利铂敏感。体内实验中，与载体对照组相比，miR-567 过表达显著抑制了 GC 细胞的肿瘤发生。机制分析表明，PIK3AP1 激活了 GC 中 AKT 的磷酸化。同时，miR-567 直接靶向 PIK3AP1 以失活 PI3K/AKT/c-Myc 通路，而 c-Myc 则反向调节 miR-567 的表达，从而形成 miR-567-PIK3AP1-PI3K/AKT-c-Myc 反馈环，解释了 miR-567 的功能。