Anhui Provincial Key Laboratory of Tumor Evolution and Intelligent Diagnosis and Treatment, Bengbu medical university, 2600 Donghai Avenue, Bengbu, Anhui 233030, China; Department of Life Sciences, Bengbu Medical University, Anhui 233030, China.
Anhui Provincial Key Laboratory of Tumor Evolution and Intelligent Diagnosis and Treatment, Bengbu medical university, 2600 Donghai Avenue, Bengbu, Anhui 233030, China; School of Laboratory Medicine, Bengbu Medical University, Anhui 233030, China.
Int Immunopharmacol. 2024 Dec 25;143(Pt 1):113261. doi: 10.1016/j.intimp.2024.113261. Epub 2024 Sep 30.
Tumor cells can escape immune surveillance by changing their own escape or expressing abnormal genes and proteins, resulting in unlimited proliferation and invasive growth of cells. These changes are related to microRNAs (miRNAs), which reduce the killing effect of immune cells, devastate the immune response, and interfere with apoptosis through the aberrant expression of relevant miRNAs. In the preliminary phase of this study, miRNAs in clinical plasma exosomes of colorectal cancer patients were differentially analyzed by RNA sequencing technology, and miR-372-5p derived from extracellular vesicles (sEVs) was found to be a key signaling molecule mediating the regulation of macrophages by colorectal cancer (CRC). miRNA-372-5p is upregulated in colorectal cancer patient tissues and serum, as well as colorectal cancer cell lines and their exosomes. Subsequently, we found that macrophages could take up sEV secreted by colorectal cancer cells HCT116, affecting the expression of the immune checkpoint PD-L1, resulting in the generation of a tumor-immunosuppressive microenvironment and suppression of T cell activation in CRC. Gene enrichment mapping and database revealed that miR-372-5p regulates PD-L1 expression in colorectal cancer through the homologous phosphatase-tensin (PTEN)-phosphatidylinositol 3-kinase-protein kinase B (AKT)-nuclear factor-κB (NF-κB) pathway. Further studies confirmed that miRNA-372-5p-treated macrophages co-cultured with T cells affected the regulation of PD-L1 expression through the PTEN/AKT/NF-κB signaling pathway, resulting in decreased CD3CD8 T cell activity, decreased cytokine IL-2 and increased IFN-γ. And miRNA-372-5p could down-regulate the expression of PD-L1 in HCT116 through the PTEN/AKT/NF-κB pathway, inhibit tumor cell proliferation and promote apoptosis. Conclusion: Colorectal cancer cell-derived exosome miR-372-5p can be phagocytosed by colorectal cancer and macrophage cells, regulate the expression of PD-L1 in colorectal cancer cells and macrophages by targeting the PTEN/AKT/NF-κB pathway, and induce the immunosuppressive microenvironment of CRC to promote CRC development. This suggests that inhibiting the secretion of HCT116-specific sEV-miR-372-5p or targeting PD-L1 in tumor-associated macrophages could be a novel approach for CRC treatment and possibly a sensitizing approach for CRC anti-PD-L1 therapy.
肿瘤细胞可以通过改变自身的逃逸或表达异常基因和蛋白来逃避免疫监视，导致细胞的无限增殖和侵袭性生长。这些变化与 microRNAs（miRNAs）有关，miRNAs 通过异常表达相关 miRNAs 降低免疫细胞的杀伤作用，破坏免疫反应，并干扰细胞凋亡。在本研究的初步阶段，通过 RNA 测序技术对结直肠癌患者临床血浆外泌体中的 miRNAs 进行了差异分析，发现源自细胞外囊泡（sEVs）的 miR-372-5p 是一种关键的信号分子，介导结直肠癌（CRC）中巨噬细胞的调节。miR-372-5p 在结直肠癌患者组织和血清以及结直肠癌细胞系及其外泌体中上调。随后，我们发现巨噬细胞可以摄取结直肠癌细胞 HCT116 分泌的 sEV，影响免疫检查点 PD-L1 的表达，导致肿瘤免疫抑制微环境的产生，并抑制 CRC 中 T 细胞的激活。基因富集图谱和数据库显示，miR-372-5p 通过同源磷酸酶 - 张力蛋白（PTEN）- 磷脂酰肌醇 3-激酶 - 蛋白激酶 B（AKT）- 核因子-κB（NF-κB）通路调节结直肠癌中的 PD-L1 表达。进一步的研究证实，用 miRNA-372-5p 处理的与 T 细胞共培养的巨噬细胞通过 PTEN/AKT/NF-κB 信号通路影响 PD-L1 表达的调节，导致 CD3+CD8+T 细胞活性降低、细胞因子 IL-2 减少和 IFN-γ增加。miRNA-372-5p 可以通过 PTEN/AKT/NF-κB 通路下调 HCT116 中 PD-L1 的表达，抑制肿瘤细胞增殖并促进细胞凋亡。结论：结直肠癌细胞来源的外泌体 miR-372-5p 可被结直肠癌细胞和巨噬细胞吞噬，通过靶向 PTEN/AKT/NF-κB 通路调节结直肠癌细胞和巨噬细胞中 PD-L1 的表达，诱导 CRC 的免疫抑制微环境，促进 CRC 的发展。这表明抑制 HCT116 特异性 sEV-miR-372-5p 的分泌或靶向肿瘤相关巨噬细胞中的 PD-L1 可能是结直肠癌治疗的一种新方法，也可能是结直肠癌抗 PD-L1 治疗的一种增敏方法。
