Inhibition of SMYD2 suppresses tumor progression by down-regulating microRNA-125b and attenuates multi-drug resistance in renal cell carcinoma
Inhibition of SMYD2 suppresses tumor progression by down-regulating microRNA-125b and attenuates multi-drug resistance in renal cell carcinoma
复制标题
抑制 SMYD2 通过下调 microRNA-125b 抑制肿瘤进展并减弱肾细胞癌的多药耐药性
作者：
Yan Libin;Ding Beichen;Liu Haoran;Zhang Yangjun;Zeng Jin;Hu Junhui;Yao Weimin;Yu Gan;An Ruihua;Chen Zhiqiang;Ye Zhangqun;Xing Jinchun;Xiao Kefeng;Wu Lily;Xu Hua
SMYD 2是一种组蛋白甲基转移酶，据报道是一种重要的表观遗传调节因子。本研究旨在探讨SMYD 2作为肾透明细胞癌（ccRCC）预后指标的作用，并探讨其在肿瘤发生和多药耐药中的作用。研究方法：收集了来自中国三家医院的186例ccRCC患者的肿瘤标本、临床病理信息和预后结果，进行SMYD 2免疫组织化学染色、Kaplan-Meier分析和考克斯比例风险回归分析。microRNA（miRNA）微阵列分析鉴定了SMYD 2敲除或用SMYD 2抑制剂AZ 505处理的肾癌细胞中差异表达的miRNA。通过细胞功能测定和小鼠异种移植实验确定SMYD 2和候选SMYD 2介导的miRNA对肾癌细胞增殖、迁移、克隆形成和致瘤性的影响。计算5种抗癌药物（顺铂、阿霉素、氟尿嘧啶、多西他赛和舒尼替尼）在AZ 505处理和对照细胞中的半抑制浓度（IC 50），并验证SMYD 2抑制对P-糖蛋白（P-gP）表达和多药耐药的影响。结果：SMYD 2在ccRCC中呈高表达，并作为癌基因发挥作用。高SMYD 2表达与高TNM分期（P = 0.007）和早期肿瘤复发（P = 0.032）相关。SMYD 2独立预测总生存率（P = 0.022）和无病生存率（P = 0.048）较差。AZ 505抑制SMYD 2与miR-125 b启动子区的结合（基于染色质免疫沉淀测定），并通过抑制SMYD 2/miR-125 b/DKK 3途径抑制ccRCC细胞迁移和侵袭。在体外和体内，SMYD 2和miR-125 b抑制通过P-gP抑制与抗癌药物协同作用。结论：这些发现表明SMYD 2在ccRCC的发展中起重要作用，并可能成为RCC治疗和预后的潜在生物标志物。
SMYD2 is a histone methyltransferase that has been reported to be an important epigenetic regulator. This study aims to investigate SMYD2 as a prognostic indicator of clear cell renal cell carcinoma (ccRCC) and explore its role in tumorigenesis and multi-drug resistance. Methods: Tumor specimens, clinicopathologic information, and prognostic outcomes of 186 ccRCC patients from three hospitals in China were collected for SMYD2 immunohistochemistry staining, Kaplan-Meier analysis, and Cox proportional hazards-regression analysis. MicroRNA (miRNA)-microarray profiling identified differentially expressed miRNAs in renal cancer cells subjected to SMYD2 knockdown or treatment with the SMYD2 inhibitor AZ505. The effects of SMYD2 and candidate SMYD2-mediated miRNAs on renal cancer cell proliferation, migration, clonogenicity, and tumorigenicity were determined via cell-function assays and murine xenograft experiments. The half-inhibitory concentrations (IC50) of five antineoplastic drugs (cisplatin, doxorubicin, fluorouracil, docetaxel, and sunitinib) in AZ505-treated and control cells were calculated, and the effects of SMYD2 inhibition on P-glycoprotein (P-gP) expression and multiple-drug resistance were verified. Results: SMYD2 was overexpressed and acted as an oncogene in ccRCC. High SMYD2 expression correlated with a high TNM stage (P = 0.007) and early tumor relapse (P = 0.032). SMYD2 independently predicted a worse overall survival (P = 0.022) and disease-free survival (P = 0.048). AZ505 inhibited the binding of SMYD2 to the miR-125b promoter region (based on chromatin immunoprecipitation assays) and suppressed ccRCC cell migration and invasion by inhibiting the SMYD2/miR-125b/DKK3 pathway. SMYD2 and miR-125b inhibition acted synergistically with anticancer drugs via P-gP suppression in vitro and in vivo. Conclusions: These findings suggested that SMYD2 plays an important role in ccRCC development and could be a potential biomarker for the treatment and prognosis of RCC.