Trauma Surgery Department, Tianjin First Central Hospital, Tianjin, China.
Burn, Frostbite and Tissue Function Reconstruction Institute, Characteristic Medical Center of PAP, Tianjin, China.
Folia Neuropathol. 2024;62(2):156-170. doi: 10.5114/fn.2024.140806.
Glioma is one of the most commonly tumours which occurs in the central nervous system and accounts for nearly 80% of brain tumours, with a significantly high mortality and morbidity. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are used as EGFR targeted therapy in various types of solid tumours; however, effective treatment for glioma is still limited. Osimertinib is an irreversible, oral third-generation TKI that targets the mutation at T790M, which causes cancer cells to acquire resistance to drugs. Osimertinib could be effective in the treatment of EGFR mutations with minimal effects on the activity of wild-type EGFR. Absent in melanoma 2 (AIM2) is highly expressed in glioma cells, promoting the maturation of pro-cancer cytokines and contributing to progression of glioma. However, the secretion of pro-cancer cytokines of tumour cells has been regarded as the resistance mechanism to EGFR-TKIs, including osimertinib. A high level of these cytokines also indicates a shorter progression-free survival (PFS). As AIM2 regulates the secretion of pro-cancer cytokines, we thought inhibition of AIM2 may contribute to the therapeutic effect of EGFR-TKIs.
We first established AIM2 inhibition and overexpression in cells. Then, the viability rate of cells was calculated by cell counting kit-8 (CCK-8) method, and apoptotic ratio of cells were measured by flow cytometry. The expression of inflammatory-related genes was detected using quantitative polymerase chain reaction (qPCR), concentrations of inflammatory-related factors were measured using enzyme-linked immunosorbent assay (ELISA). The expression of Wnt/b-catenin and EGFR/Ras/Mitogen-activated protein kinase kinase 1 (MEK) signalling pathway components was detected using western blotting.
We found that inhibition of AIM2 enlarged the effect of osimertinib on the upregulation of inflammatory gene expression and secretion of these genes, increasing apoptosis. In addition, we also found that AIM2 could enhance the effect of osimertinib on reducing the expression of the Wnt/b-catenin and EGFR/Ras/MEK signalling pathways, resulting in the inhibition of cellular proliferation, and exerting an anti-tumour effect. These effects were also observed using in vivo experiments.
AIM2 presents a potential therapeutic target in treatment of glioma.
脑胶质瘤是中枢神经系统最常见的肿瘤之一，约占脑肿瘤的 80%，死亡率和发病率都很高。表皮生长因子受体（EGFR）酪氨酸激酶抑制剂（TKIs）被用作各种实体肿瘤的 EGFR 靶向治疗药物；然而，对脑胶质瘤的有效治疗仍然有限。奥希替尼是一种不可逆的、口服的第三代 TKI，针对导致癌细胞对药物产生耐药性的 T790M 突变。奥希替尼可能对野生型 EGFR 活性的影响最小，对 EGFR 突变有效。缺失在黑色素瘤 2（AIM2）中在神经胶质瘤细胞中高度表达，促进致癌细胞因子的成熟，并有助于神经胶质瘤的进展。然而，肿瘤细胞的致癌细胞因子的分泌一直被认为是 EGFR-TKIs 的耐药机制，包括奥希替尼。这些细胞因子的高水平也预示着无进展生存期（PFS）更短。由于 AIM2 调节致癌细胞因子的分泌，我们认为抑制 AIM2 可能有助于 EGFR-TKIs 的治疗效果。
我们首先在细胞中建立 AIM2 的抑制和过表达。然后，通过细胞计数试剂盒-8（CCK-8）法计算细胞存活率，通过流式细胞术测量细胞凋亡率。使用定量聚合酶链反应（qPCR）检测炎症相关基因的表达，使用酶联免疫吸附测定（ELISA）测量炎症相关因子的浓度。使用 Western blot 检测 Wnt/b-catenin 和 EGFR/Ras/丝裂原活化蛋白激酶激酶 1（MEK）信号通路成分的表达。
我们发现，抑制 AIM2 扩大了奥希替尼对上调炎症基因表达和这些基因分泌的作用，增加了细胞凋亡。此外，我们还发现 AIM2 可以增强奥希替尼对降低 Wnt/b-catenin 和 EGFR/Ras/MEK 信号通路表达的作用，从而抑制细胞增殖，发挥抗肿瘤作用。在体内实验中也观察到了这些作用。
AIM2 是治疗脑胶质瘤的潜在治疗靶点。
