The Fourth Department of Medical Oncology, Harbin Medical University Cancer Hospital, 150 Haping Road, Harbin, 150040, China.
Department of Gynecology, Harbin Medical University Cancer Hospital, Harbin Medical University, 150 Haping Road, Harbin, 150040, China.
Cell Commun Signal. 2018 Jul 31;16(1):43. doi: 10.1186/s12964-018-0254-x.
The highly refractory nature of non-small cell lung cancer (NSCLC) to chemotherapeutic drugs is an important factor resulting in its poor prognosis. Recent studies have revealed that tumour necrosis factor alpha-induced protein 8 (TNFAIP8) is involved in various biological and pathological processes of cells, but their underlying mechanisms in processes ranging from cancer development to drug resistance have not been fully elucidated.
TNFAIP8 expression in clinical NSCLC samples was examined through immunohistochemistry (IHC). After adjusting for patients' characteristics with propensity score matching, Kaplan-Meier analysis and Cox regression analysis were performed for comparison of patients' survival according to the TNFAIP8 level. Lentiviral transfection with TNFAIP8-specific shRNAs was used to establish stable TNFAIP8 knockdown (TNFAIP8 KD) NCI-H460, A549 and cis-diamminedichloroplatinum II resistant A549 (A549/cDDP) cell lines. Cell proliferation and viability were assessed by CCK-8 assay. Cell cycle was examined by flow cytometry. Multiple pathways regulated by TNFAIP8 KD were revealed by microarray analysis.
We found that high TNFAIP8 expression was associated with advanced pT stage, advanced pTNM stage, lymph node metastasis and unfavourable survival in NSCLC patients. TNFAIP8 shRNAs reduced in vitro cancer cell proliferation and in vivo tumor growth. Additionally, TNFAIP8 KD increased the sensitivity of NSCLC cells to cisplatin in vitro and in vivo. Conversely, up-regulation of TNFAIP8 promoted the proliferation and drug resistance to cisplatin of NSCLC cells. TNFAIP8 influences cancer progression pathways involving the MDM2/p53 pathway. Indeed, we observed that TNFAIP8 KD mediated the MDM2 downregulation and the p53 ubiquitination, thereby decreasing the degradation of p53 protein. shRNA p53 reversed TNFAIP8 shRNA-mediated regulation of cell proliferation, cell cycle, cisplatin sensitivity, and expression levels of RAD51, a DNA repair gene.
Our work uncovers a hitherto unappreciated role of TNFAIP8 in NSCLC proliferation and cisplatin chemoresistance that is mediated through the MDM2/p53 pathway. These findings might offer potential therapeutic targets for reversing cisplatin resistance in NSCLC patients with high TNFAIP8 expression.
非小细胞肺癌（NSCLC）对化疗药物的高度耐药性是导致其预后不良的重要因素。最近的研究表明，肿瘤坏死因子-α诱导蛋白 8（TNFAIP8）参与了细胞的各种生物学和病理过程，但它们在从癌症发展到耐药性的过程中的潜在机制尚未完全阐明。
通过免疫组织化学（IHC）检测临床 NSCLC 样本中的 TNFAIP8 表达。通过倾向评分匹配调整患者特征后，根据 TNFAIP8 水平比较患者的生存情况，进行 Kaplan-Meier 分析和 Cox 回归分析。使用 TNFAIP8 特异性 shRNA 的慢病毒转染建立稳定的 TNFAIP8 敲低（TNFAIP8 KD）NCI-H460、A549 和顺铂耐药 A549（A549/cDDP）细胞系。通过 CCK-8 测定评估细胞增殖和活力。通过流式细胞术检查细胞周期。通过微阵列分析揭示 TNFAIP8 KD 调节的多个途径。
我们发现，TNFAIP8 高表达与 NSCLC 患者的晚期 pT 期、晚期 pTNM 期、淋巴结转移和不良生存相关。TNFAIP8 shRNA 降低了体外癌细胞增殖和体内肿瘤生长。此外，TNFAIP8 KD 增加了 NSCLC 细胞对顺铂的体外和体内敏感性。相反，TNFAIP8 的上调促进了 NSCLC 细胞对顺铂的增殖和耐药性。TNFAIP8 影响涉及 MDM2/p53 途径的癌症进展途径。事实上，我们观察到 TNFAIP8 KD 介导了 MDM2 的下调和 p53 的泛素化，从而减少了 p53 蛋白的降解。shRNA p53 逆转了 TNFAIP8 shRNA 介导的细胞增殖、细胞周期、顺铂敏感性和 DNA 修复基因 RAD51 表达水平的调节。
我们的工作揭示了 TNFAIP8 在 NSCLC 增殖和顺铂化疗耐药性中的作用，该作用是通过 MDM2/p53 途径介导的。这些发现可能为逆转高 TNFAIP8 表达的 NSCLC 患者对顺铂的耐药性提供潜在的治疗靶点。
