Department of General Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an City 710004, Shaanxi, China.
Department of Anesthesiology and Operation, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an City 710004, Shaanxi, China.
Int Immunopharmacol. 2024 Sep 10;138:112282. doi: 10.1016/j.intimp.2024.112282. Epub 2024 Jun 26.
Hypoxia is a hallmark of solid tumors. Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment, and CAF-derived exosomes are involved in cancer genesis and progression. Here, this work investigated the role and mechanism of exosomal circHIF1A derived from hypoxia-induced CAFs in hepatocellular carcinoma (HCC) tumorigenesis. CAFs isolated from fresh HCC tissues were incubated in normoxia or hypoxia condition (N/CAFs or H/CAFs), and then the exosomes from N/CAFs or H/CAFs were isolated for functional analysis. Cell proliferation, migration and invasion were analyzed by cell counting kit-8, colony formation, and transwell assays. Immune evasion was evaluated by measuring the cytotoxicity and viability of CD8T cells. qRT-PCR and western blotting analyses were used for the level measurement of genes and proteins. The binding between Hu antigen R (HuR) and circHIF1A or Programmed death ligand 1 (PD-L1) was analyzed by RNA immunoprecipitation assay. Functionally, we found that CAFs, especially CAFs under hypoxic stress (H/CAFs), promoted the proliferation, migration, invasion and EMT progression in HCC cells, as well as induced immune escape by suppressing CD8T cell cytotoxicity and activity in an exosome-dependent manner. H/CAFs-derived exosomes showed highly expressed circHIF1A, and could secrete circHIF1A into HCC cells via exosomes. The oncogenic effects of H/CAFs-secreted exosomes were abolished by circHIF1A knockdown. Mechanistically, circHIF1A interacted with HuR to stabilize PD-L1 expression in HCC cells. Meanwhile, circHIF1A silencing suppressed HCC cell proliferation, mobility and immune escape by regulating PD-L1 expression. In all, exosomal circHIF1A derived from hypoxic-induced CAFs promoted the proliferation, migration, invasion, EMT progression and immune escape in HCC cells by up-regulating PD-L1 expression in a HuR-dependent manner.
缺氧是实体瘤的一个标志。癌症相关成纤维细胞(CAFs)是肿瘤微环境的重要组成部分,CAF 衍生的外泌体参与癌症的发生和进展。在这里,这项工作研究了来自缺氧诱导的 CAFs 的外泌体 circHIF1A 在肝细胞癌(HCC)肿瘤发生中的作用和机制。从新鲜 HCC 组织中分离的 CAFs 在常氧或低氧条件下孵育(N/CAFs 或 H/CAFs),然后分离 N/CAFs 或 H/CAFs 的外泌体进行功能分析。通过细胞计数试剂盒-8、集落形成和 Transwell 分析来分析细胞增殖、迁移和侵袭。通过测量 CD8T 细胞的细胞毒性和活力来评估免疫逃逸。qRT-PCR 和 Western blot 分析用于测量基因和蛋白质的水平。通过 RNA 免疫沉淀测定分析 Hu 抗原 R(HuR)与 circHIF1A 或程序性死亡配体 1(PD-L1)之间的结合。功能上,我们发现 CAFs,特别是缺氧应激下的 CAFs(H/CAFs),以依赖外泌体的方式促进 HCC 细胞的增殖、迁移、侵袭和 EMT 进展,并通过抑制 CD8T 细胞的细胞毒性和活性诱导免疫逃逸。H/CAFs 衍生的外泌体显示出高度表达的 circHIF1A,并可以通过外泌体将 circHIF1A 分泌到 HCC 细胞中。circHIF1A 敲低消除了 H/CAFs 分泌的外泌体的致癌作用。机制上,circHIF1A 与 HuR 相互作用,稳定 HCC 细胞中 PD-L1 的表达。同时,circHIF1A 沉默通过调节 PD-L1 表达抑制 HCC 细胞的增殖、迁移和免疫逃逸。总之,来自缺氧诱导的 CAFs 的外泌体 circHIF1A 通过依赖 HuR 的方式上调 PD-L1 表达,促进 HCC 细胞的增殖、迁移、侵袭、EMT 进展和免疫逃逸。
Clin Exp Med. 2025-4-24
Adv Sci (Weinh). 2025-3