DNA Methylation-regulated miR-193a-3p Dictates Resistance of Hepatocellular Carcinoma to 5-Fluorouracil via Repression of SRSF2 Expression
DNA Methylation-regulated miR-193a-3p Dictates Resistance of Hepatocellular Carcinoma to 5-Fluorouracil via Repression of SRSF2 Expression
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DOI：
10.1074/jbc.m111.291229
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发表时间：
2012-02-17
影响因子：
4.8
通讯作者：
Zhu, Jingde
中科院分区：
文献类型：
--
作者：
Ma, Kelong;He, Yinghua;Zhu, Jingde
化疗耐药性阻碍了有效的癌症治疗，并且在治疗前很少可预测，特别是对于肝细胞癌（HCC）。在对8种HCC细胞系对9种化疗药物中的每一种进行耐药性分析后，系统地研究了2种细胞系（QGY-7703作为对5-氟尿嘧啶（5-FU）治疗敏感的细胞系，SMMC-7721作为对5-FU治疗耐药的细胞系），以了解HCC 5-FU耐药性的机制。DNA甲基化和microRNA（miR）水平的基因组分析以及随后的机制研究阐明了DNA甲基化调控的miR-193 a-3 p如何通过抑制富含丝氨酸/丝氨酸的剪接因子2（SRSF 2）表达来决定HCC细胞的5-FU耐药性的新机制。反过来，SRSF 2优先上调caspase 2（CASP 2L）的促凋亡剪接形式，并使HCC细胞对5-FU敏感。在细胞培养物和裸小鼠中，miR-193 a-3 p水平的强制变化逆转了检查的所有表型特征，包括细胞增殖、细胞周期进展和5-FU敏感性。重要的是，siRNA介导的SRSF 2抑制表型复制了QGY-7703中所有miR-193 a-3 p模拟触发的变化。这种新发现的miR 193 a-3 p-SRSF 2轴突出了HCC最佳5-FU治疗所需的一组新的伴随诊断，其涉及分析miR-193 a基因的DNA甲基化状态和miR-193 a-3 p和SRSF 2的表达以及临床样品中caspase 2的促凋亡与抗凋亡剪接形式的相对水平。
Chemoresistance prevents effective cancer therapy and is rarely predictable prior to treatment, particularly for hepatocellular carcinoma (HCC). Following the chemoresistance profiling of eight HCC cell lines to each of nine chemotherapeutics, two cell lines (QGY-7703 as a sensitive and SMMC-7721 as a resistant cell line to 5-fluorouracil (5-FU) treatment) were systematically studied for mechanistic insights underpinning HCC 5-FU chemoresistance. Genomic profiling at both DNA methylation and microRNA (miR) levels and subsequent mechanistic studies illustrate a new mechanism for how DNA methylation-regulated miR-193a-3p dictates the 5-FU resistance of HCC cells via repression of serine/arginine-rich splicing factor 2 (SRSF2) expression. In turn, SRSF2 preferentially up-regulates the proapoptotic splicing form of caspase 2 (CASP2L) and sensitizes HCC cells to 5-FU. Forced changes of miR-193a-3p level reverse all of the phenotypic features examined, including cell proliferation, cell cycle progression, and 5-FU sensitivity, in cell culture and in nude mice. Importantly, the siRNA-mediated repression of SRSF2 phenocopies all of the miR-193a-3p mimic-triggered changes in QGY-7703. This newly identified miR193a-3p-SRSF2 axis highlights a new set of companion diagnostics required for optimal 5-FU therapy of HCC, which involve assaying both the DNA methylation state of the miR-193a gene and the expression of miR-193a-3p and SRSF2 and the relative level of the proapoptotic versus antiapoptotic splicing forms of caspase 2 in clinical samples.