The First Clinical Medical College of Jinan University, Guangdong 530632, China; Department of Orthopedics, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi 533000, China; Guangxi Clinical Medical Research Center for Hepatobiliary Diseases, Baise, Guangxi 533000, China; Guangxi Zhuang Autonomous Region Engineering Research Center for Biomaterials in Bone and Joint Degenerative Diseases, Baise, Guangxi 533000,China.
The First Clinical Medical College of Jinan University, Guangdong 530632, China; Guangxi Clinical Medical Research Center for Hepatobiliary Diseases, Baise, Guangxi 533000, China; Department of Gastroenterology, Affiliated Hospital of Youjiang Medical University for Nationalities, No.18 Zhongshan 2nd Road, Baise, 533000, Guangxi Province, China.
Int J Biol Macromol. 2024 Nov;281(Pt 3):136459. doi: 10.1016/j.ijbiomac.2024.136459. Epub 2024 Oct 11.
Hepatocellular carcinoma (HCC) is characterized by a complex tumor microenvironment (TME), and long non-coding RNAs (lncRNAs) MEG3 emerged as regulators of macrophage polarization with a negative relationship with colony-stimulating factor 1 (CSF-1). Few studies are on the interplay among MEG3, CSF-1, T helper cells (Th), and the programmed cell death protein 1 and its ligands (PD-1/PD-Ls) in TME of HCC.MEG3 expression in THP-1 macrophages, monitored polarization, and PD-1/PD-Ls expression were through flow cytometry, WB, and RT-qPCR. In co-cultures, the interaction of MEG3, macrophage, and HCC was assayed by ELISA. The invasive and migratory of HCC were assessed through experiments such as CCK-8, clonogenic assay, wound healing, and Transwell. A xenograft mouse model of HCC was established, administered with MEG3 overexpression (OE) or knockdown (KD) constructs, and monitored tumor growth. In vitro, MEG3 OE induced a robust M1 macrophage phenotype, evidenced by elevated expression of M1 markers and a significant increase in Th1 cytokines, with a concomitant decrease in Th2 cytokines. This was paralleled by reduced CSF-1 and PD-1/PD-Ls expression. In contrast, MEG3 KD promoted an M2 phenotype with increased CSF-1 and PD-1/PD-Ls expression, and an upregulation of Th2 cytokines. MEG3 OE inhibited the growth, invasion, and migration of HCC, while the opposite was observed when MEG3 was downregulated. In vivo, MEG3 OE resulted in significantly reduced tumor growth, with decreased PD-1/PD-Ls expression on macrophages and enhanced Th1 response. Conversely, MEG3 KD promoted tumor growth with increased PD-1/PD-Ls and a Th2-skewed immune response. MEG3 modulates the TME by affecting TAMs through CSF-1, thereby influencing the balance of Th1/Th2 cells and altering the expression of PD-1/PD-L1s. This study demonstrates that targeting MEG3 is an effective therapeutic strategy for HCC.
肝细胞癌（HCC）的特点是肿瘤微环境（TME）复杂，长链非编码 RNA（lncRNA）MEG3 作为巨噬细胞极化的调节剂出现，与集落刺激因子 1（CSF-1）呈负相关。目前很少有研究涉及 MEG3、CSF-1、辅助性 T 细胞（Th）和程序性细胞死亡蛋白 1 及其配体（PD-1/PD-Ls）在 HCC 的 TME 中的相互作用。通过流式细胞术、WB 和 RT-qPCR 监测 THP-1 巨噬细胞中的 MEG3 表达、极化和 PD-1/PD-Ls 表达。在共培养物中，通过 ELISA 检测 MEG3、巨噬细胞和 HCC 的相互作用。通过 CCK-8、集落形成实验、划痕愈合和 Transwell 实验评估 HCC 的侵袭和迁移。建立 HCC 的异种移植小鼠模型，给予 MEG3 过表达（OE）或敲低（KD）构建体，并监测肿瘤生长。在体外，MEG3 OE 诱导出强大的 M1 巨噬细胞表型，表现为 M1 标志物表达升高，Th1 细胞因子显著增加，同时 Th2 细胞因子减少。这与 CSF-1 和 PD-1/PD-Ls 表达降低相对应。相反，MEG3 KD 促进了 M2 表型，CSF-1 和 PD-1/PD-Ls 表达增加，Th2 细胞因子上调。MEG3 OE 抑制 HCC 的生长、侵袭和迁移，而 MEG3 下调则相反。在体内，MEG3 OE 导致肿瘤生长明显减少，巨噬细胞上的 PD-1/PD-Ls 表达降低，Th1 反应增强。相反，MEG3 KD 促进肿瘤生长，PD-1/PD-Ls 增加，Th2 免疫反应偏向。MEG3 通过 CSF-1 调节 TME，从而影响 TAMs，影响 Th1/Th2 细胞的平衡，并改变 PD-1/PD-L1s 的表达。本研究表明，靶向 MEG3 是治疗 HCC 的有效策略。
