Ding Lijuan, Wang Nanya, Wang Qiang, Fan Xia, Xin Yuning, Wang Shudong
Department of Radiation Oncology, the First Hospital of Jilin University, Changchun, 130021, China.
Cancer Center, the First Hospital of Jilin University, Changchun, 130021, China.
Cell Death Discov. 2023 Mar 11;9(1):92. doi: 10.1038/s41420-023-01392-3.
Sorafenib, a multiple-target tyrosine kinase inhibitor, is the standard of care for patients with advanced hepatocellular carcinoma (HCC), but provides limited benefits. Emerging evidences suggest that prolonged sorafenib treatment induces an immunosuppressive HCC microenvironment, but the underling mechanism is undetermined. In the present study, the potential function of midkine, a heparin-binding growth factor/cytokine, was evaluated in sorafenib-treated HCC tumors. Infiltrating immune cells of orthotopic HCC tumors were measured by flow cytometry. Differentially expressed genes in sorafenib-treated HCC tumors were evaluated by transcriptome RNA sequencing. The potential function of midkine were evaluated by western blot, T cell suppression assay, immunohistochemistry (IHC) staining and tumor xenograft model. We found that sorafenib treatment increased intratumoral hypoxia and altered HCC microenvironment towards an immune-resistant state in orthotopic HCC tumors. Sorafenib treatment promoted midkine expression and secretion by HCC cells. Moreover, forced midkine expression stimulated immunosuppressive myeloid-derived suppressor cells (MDSCs) accumulation in HCC microenvironment, while knockdown of midkine exhibited opposite effects. Furthermore, midkine overexpression promoted CD11bCD33HLA-DR MDSCs expansion from human PBMCs, while midkine depletion suppressed this effect. PD-1 blockade showed no obvious inhibition on tumor growth of sorafenib-treated HCC tumors, but the inhibitory effect was greatly enhanced by midkine knockdown. Besides, midkine overexpression promoted multiple pathways activation and IL-10 production by MDSCs. Our data elucidated a novel role of midkine in the immunosuppressive microenvironment of sorafenib-treated HCC tumors. Mikdine might be a potential target for the combination of anti-PD-1 immunotherapy in HCC patients.
索拉非尼是一种多靶点酪氨酸激酶抑制剂，是晚期肝细胞癌（HCC）患者的标准治疗药物，但疗效有限。新出现的证据表明，索拉非尼的长期治疗会诱导免疫抑制性HCC微环境，但其潜在机制尚未明确。在本研究中，我们评估了肝素结合生长因子/细胞因子中期因子在索拉非尼治疗的HCC肿瘤中的潜在作用。通过流式细胞术检测原位HCC肿瘤中浸润的免疫细胞。通过转录组RNA测序评估索拉非尼治疗的HCC肿瘤中差异表达的基因。通过蛋白质免疫印迹、T细胞抑制试验、免疫组织化学（IHC）染色和肿瘤异种移植模型评估中期因子的潜在功能。我们发现，索拉非尼治疗会增加原位HCC肿瘤内的缺氧情况，并使HCC微环境向免疫抵抗状态转变。索拉非尼治疗可促进HCC细胞中期因子的表达和分泌。此外，强制表达中期因子会刺激免疫抑制性骨髓来源的抑制细胞（MDSC）在HCC微环境中的积累，而敲低中期因子则会产生相反的效果。此外，中期因子的过表达促进了人外周血单个核细胞（PBMC）中CD11bCD33HLA-DR MDSC的扩增，而中期因子的缺失则抑制了这种效应。PD-1阻断对索拉非尼治疗的HCC肿瘤生长没有明显抑制作用，但敲低中期因子可大大增强这种抑制作用。此外，中期因子的过表达促进了MDSC的多种信号通路激活和IL-10的产生。我们的数据阐明了中期因子在索拉非尼治疗的HCC肿瘤免疫抑制微环境中的新作用。中期因子可能是HCC患者抗PD-1免疫治疗联合方案的潜在靶点。
