Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.
Department of Graduate School, Anhui Medical University, Hefei 230032, China.
Cells. 2022 Nov 30;11(23):3857. doi: 10.3390/cells11233857.
Currently, exosomes derived from Cancer-associated fibroblast (CAF) have reportedly been involved in regulating hepatocellular carcinoma (HCC) tumour microenvironment (TME). LIM domain and actin binding 1 (LIMA1) is an actin-binding protein that is involved in controlling the biological behaviour and progression of specific solid tumours. We aimed to determine the effect of LIMA1 and exosome-associated miR-20a-5p in HCC development. LIMA1 and miR-20a-5p expression levels were examined by real-time quantitative PCR (qRT-PCR), western blotting or immunohistochemistry (IHC). Functional experiments, including Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) assays, colony formation assays, wound healing assays, and Transwell invasion assays, were performed to investigate the effect of LIMA1 and miR-20a-5p. A dual-luciferase reporter gene assay was performed to confirm the interaction of miR-20a-5p and LIMA1. Exosomes were characterised by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting. We noted that LIMA1 was downregulated in human HCC tissues and cells and remarkably correlated with overall survival (OS) and recurrence-free survival (RFS). LIMA1 overexpression suppressed HCC cell proliferation and metastasis in vitro and in vivo, while LIMA1 knockdown had the opposite effects. A mechanistic investigation showed that LIMA1 inhibited the Wnt/β-catenin signalling pathway by binding to BMI1 and inducing its destabilisation. Additionally, we found that LIMA1 expression in HCC cells could be suppressed by transferring CAF-derived exosomes harbouring oncogenic miR-20a-5p. In summary, LIMA1 is a tumour suppressor that inhibits the Wnt/β-catenin signalling pathway and is downregulated by CAF-derived exosomes carrying oncogenic miR-20a-5p in HCC.
目前，已有报道称源自癌相关成纤维细胞（CAF）的外泌体参与调控肝细胞癌（HCC）肿瘤微环境（TME）。LIM 结构域和肌动蛋白结合蛋白 1（LIMA1）是一种肌动蛋白结合蛋白，参与调控特定实体瘤的生物学行为和进展。本研究旨在探究 LIMA1 和外泌体相关 miR-20a-5p 在 HCC 发生发展中的作用。采用实时定量 PCR（qRT-PCR）、western blot 或免疫组化（IHC）检测 LIMA1 和 miR-20a-5p 的表达水平。通过细胞计数试剂盒-8（CCK-8）、5-乙炔基-2'-脱氧尿苷（EdU）检测、集落形成实验、划痕愈合实验和 Transwell 侵袭实验进行功能实验，以研究 LIMA1 和 miR-20a-5p 的作用。通过双荧光素酶报告基因实验证实 miR-20a-5p 与 LIMA1 之间的相互作用。采用透射电子显微镜（TEM）、纳米颗粒跟踪分析（NTA）和 western blot 对 exosomes 进行鉴定。研究结果表明，LIMA1 在人 HCC 组织和细胞中表达下调，且与总生存期（OS）和无复发生存期（RFS）显著相关。LIMA1 过表达可抑制 HCC 细胞在体外和体内的增殖和转移，而 LIMA1 敲低则具有相反的作用。机制研究表明，LIMA1 通过与 BMI1 结合并诱导其不稳定来抑制 Wnt/β-catenin 信号通路。此外，我们发现 HCC 细胞中的 LIMA1 表达可通过转染携带致癌性 miR-20a-5p 的 CAF 衍生外泌体来抑制。综上所述，LIMA1 是一种肿瘤抑制因子，可抑制 Wnt/β-catenin 信号通路，并且在 HCC 中可被携带致癌性 miR-20a-5p 的 CAF 衍生外泌体下调。
