MET 抑制剂通过稳定 PD-L1 促进肝脏肿瘤逃避免疫反应。
MET Inhibitors Promote Liver Tumor Evasion of the Immune Response by Stabilizing PDL1.
机构信息
Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai, People's Republic of China.
Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
出版信息
Gastroenterology. 2019 May;156(6):1849-1861.e13. doi: 10.1053/j.gastro.2019.01.252. Epub 2019 Jan 31.
BACKGROUND & AIMS: Inhibitors of MET have not produced satisfactory outcomes in trials of patients with liver cancer. We investigated the mechanisms of liver tumor resistance to MET inhibitors in mice.
METHODS
We tested the effects of MET inhibitors tivantinib and capmatinib in the mouse hepatocellular carcinoma (HCC) cell line HCA-1 and in immune-competent and immunodeficient mice with subcutaneous tumors grown from this cell line. Tumors were collected from mice and tumor cells were analyzed by time-of-flight mass cytometry. We used short hairpin RNAs to weaken expression of MET in Hep3B, SK-HEP-1, HA59T, and HA22T liver cancer cell lines and analyzed cells by immunoblot, immunofluorescence, and immunoprecipitation assays. Mass spectrometry was used to assess interactions between MET and glycogen synthase kinase 3β (GSK3B), and GSK3B phosphorylation, in liver cancer cell lines. C57/BL6 mice with orthotopic tumors grown from Hep1-6 cells were given combinations of capmatinib or tivantinib and antibodies against programmed cell death 1 (PDCD1; also called PD1); tumors were collected and analyzed by immunofluorescence. We analyzed 268 HCCsamples in a tissue microarray by immunohistochemistry.
RESULTS
Exposure of liver cancer cell lines to MET inhibitors increased their expression of PD ligand 1 (PDL1) and inactivated cocultured T cells. MET phosphorylated and activated GSK3B at tyrosine 56, which decreased the expression of PDL1 by liver cancer cells. In orthotopic tumors grown in immune-competent mice, MET inhibitors decreased the antitumor activity of T cells. However, addition of anti-PD1 decreased orthotopic tumor growth and prolonged survival of mice compared with anti-PD1 or MET inhibitors alone. Tissue microarray analysis of HCC samples showed an inverse correlation between levels of MET and PDL1 and a positive correlation between levels of MET and phosphorylated GSK3B.
CONCLUSIONS
In studies of liver cancer cell lines and mice with orthotopic tumors, MET mediated phosphorylation and activated GSK3B, leading to decreased expression of PDL1. Combined with a MET inhibitor, anti-PD1 and anti-PDL1 produced additive effect to slow growth of HCCs in mice.
背景与目的
MET 抑制剂在肝癌患者的临床试验中并未取得令人满意的结果。我们研究了 MET 抑制剂在小鼠肝癌肿瘤中的耐药机制。
方法
我们在小鼠肝癌细胞系 HCA-1 及其衍生的皮下肿瘤的免疫功能正常和免疫缺陷小鼠中，检测 MET 抑制剂 tivantinib 和 capmatinib 的作用。从小鼠肿瘤中收集肿瘤细胞，通过飞行时间质谱细胞术进行分析。我们使用短发夹 RNA 减弱 Hep3B、SK-HEP-1、HA59T 和 HA22T 肝癌细胞系中 MET 的表达，并通过免疫印迹、免疫荧光和免疫沉淀实验分析细胞。质谱法用于评估 MET 与糖原合酶激酶 3β（GSK3β）之间的相互作用，以及 GSK3β 在肝癌细胞系中的磷酸化作用。从小鼠肝癌细胞系 Hep1-6 衍生的原位肿瘤中，C57/BL6 小鼠接受 capmatinib 或 tivantinib 与程序性细胞死亡蛋白 1（PDCD1；也称为 PD1）抗体的联合治疗；收集肿瘤并通过免疫荧光进行分析。我们通过免疫组化分析了组织微阵列中的 268 个 HCC 样本。
结果
肝癌细胞系暴露于 MET 抑制剂后，其 PD 配体 1（PDL1）表达增加，并使共培养的 T 细胞失活。MET 使 GSK3β 在酪氨酸 56 位磷酸化并激活，从而降低肝癌细胞的 PDL1 表达。在免疫功能正常的小鼠中，MET 抑制剂降低了 T 细胞的抗肿瘤活性。然而，与单独使用抗 PD1 或 MET 抑制剂相比，添加抗 PD1 可减少原位肿瘤的生长并延长小鼠的生存时间。HCC 样本的组织微阵列分析显示，MET 水平与 PDL1 呈负相关，而 MET 水平与磷酸化 GSK3β 呈正相关。
结论
在肝癌细胞系和原位肿瘤小鼠的研究中，MET 介导的磷酸化和激活 GSK3β 导致 PDL1 表达降低。与 MET 抑制剂联合使用，抗 PD1 和抗 PDL1 可协同作用，减缓 HCC 在小鼠中的生长。
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