结直肠癌是影响胃肠道的最常见恶性肿瘤之一。肝转移是大约 50% 结直肠癌患者中存在的一种并发症，是一个值得关注的问题。最近，研究揭示了miR-455在肿瘤发病机制中的关键作用。然而，miR-455对结直肠癌肝转移进展的影响仍存在争议。作为骨形态发生蛋白 (BMP) 的拮抗剂，Gremlin 1 (GREM1) 可能会影响器官发生、身体模式和组织分化。然而，miR-455在结直肠癌肝转移中调控GREM1的作用以及miR-455/GREM1轴如何影响肿瘤免疫微环境尚不清楚。生物信息学分析表明miR-455/GREM1轴在肠癌肝转移中发挥着至关重要的作用并预测其可能的机制。为了研究miR-455/GREM1轴对结直肠癌细胞增殖、侵袭和迁移的影响，我们在体外进行了集落形成实验、伤口愈合实验和Transwell实验。双荧光素酶报告基因测定和 RNA Pull-down 测定证实了 miR-455 和 GREM1 之间可能存在的调节作用。体内建立结直肠癌肝转移（CRLM）小鼠模型，探讨miR-455/GREM1轴对肿瘤生长和巨噬细胞极化的影响。采用免疫荧光（IF）和实时定量聚合酶链反应（qRT-PCR）检测巨噬细胞极化标志物。通过酶联免疫吸附试验（ELISA）检测培养液上清液中的细胞因子。我们发现与原发肿瘤相比，肝转移瘤中miR-455和BMP6表达增加，GREM1表达减少。 miR-455/GREM1轴通过受影响的PI3K/AKT通路促进结直肠癌细胞增殖、迁移、侵袭。此外，下调GREM1可增强MC38细胞系中BMP6的表达，诱导巨噬细胞M2极化，并促进CRLM模型小鼠的肝转移生长。这些数据表明miR-455/GREM1轴通过影响PI3K/AKT促进结直肠癌进展和肝转移途径并诱导 M2 巨噬细胞极化。这些结果为 CRLM 的未来研究和治疗提供了宝贵的见解和方向。© 2024。作者。

Colorectal cancer is among the most common malignant tumors affecting the gastrointestinal tract. Liver metastases, a complication present in approximately 50% of colorectal cancer patients, are a considerable concern. Recently, studies have revealed the crucial role of miR-455 in tumor pathogenesis. However, the effect of miR-455 on the progression of liver metastases in colorectal cancer remains controversial. As an antagonist of bone morphogenetic protein(BMP), Gremlin 1 (GREM1) may impact organogenesis, body patterning, and tissue differentiation. Nevertheless, the role of miR-455 in regulating GREM1 in colorectal cancer liver metastases and how miR-455/GREM1 axis influences tumour immune microenvironment is unclear.Bioinformatics analysis shows that miR-455/GREM1 axis plays crucial role in liver metastasis of intestinal cancer and predicts its possible mechanism. To investigate the impact of miR-455/GREM1 axis on the proliferation, invasion, and migration of colorectal cancer cells, colony formation assay, wound healing and transwell assay were examined in vitro. The Dual-Luciferase reporter gene assay and RNA pull-down assay confirmed a possible regulatory effect between miR-455 and GREM1. In vivo, colorectal cancer liver metastasis(CRLM) model mice was established to inquiry the effect of miR-455/GREM1 axis on tumor growth and macrophage polarization. The marker of macrophage polarization was tested using immunofluorescence(IF) and quantitative real-time polymerase chain reaction(qRT-PCR). By enzyme-linked immunosorbent assay (ELISA), cytokines were detected in culture medium supernatants.We found that miR-455 and BMP6 expression was increased and GREM1 expression was decreased in liver metastase compared with primary tumor. miR-455/GREM1 axis promotes colorectal cancer cells proliferation, migration, invasion via affected PI3K/AKT pathway. Moreover, downregulating GREM1 augmented BMP6 expression in MC38 cell lines, inducing M2 polarization of macrophages, and promoting liver metastasis growth in CRLM model mice.These data suggest that miR-455/GREM1 axis promotes colorectal cancer progression and liver metastasis by affecting PI3K/AKT pathway and inducing M2 macrophage polarization. These results offer valuable insights and direction for future research and treatment of CRLM.© 2024. The Author(s).