Department of Cardiothoracic Surgery, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-sen University, Shantou, Guangdong 515041, China.
Department of Pathology, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-sen University, Shantou, Guangdong 515041, China.
Biomed Res Int. 2017;2017:9592501. doi: 10.1155/2017/9592501. Epub 2017 Oct 2.
LCN2 is involved in various cellular functions, including transport of small hydrophobic molecules, protection of MMP9 from proteolytic degradation, and regulating innate immunity. LCN2 is elevated in multiple human cancers, frequently being associated with tumor size, stage, and invasiveness. Our previous studies have shown that LCN2 expression could be induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in esophageal squamous cell carcinoma (ESCC) by the binding of five nucleoproteins (MISP, KLF10, KLF15, PPP1R18, and RXR) at a novel TPA-responsive element (TRE), at -152~-60 bp of the 5' flanking region of the promoter. However, much is unknown about whether these proteins can respond to TPA stimulation to regulate LCN2 transactivation and which cell signaling pathways mediate this process. In this study, expression plasmids encoding these five nucleoproteins were stably transfected into EC109 cells. Then, stable transfectant was characterized by a Dual-Luciferase Reporter Assay System. RT-PCR, real-time PCR, western blotting, specific kinase inhibitor treatment, and bioinformatics analyses were applied in this study. We found that MISP, KLF10, KLF15, PPP1R18, and RXR proteins could strongly respond to TPA stimulation and activate LCN2 transcriptional expression. MEK, ERK, JNK, and P38 kinases were involved in the LCN2 transactivation. Furthermore, the MEK-ERK signal pathway plays a major role in this biological process but does not involve PKC signaling.
LCN2 参与多种细胞功能，包括小分子疏水性分子的转运、MMP9 免受蛋白水解降解的保护，以及调节先天免疫。LCN2 在多种人类癌症中升高，通常与肿瘤大小、分期和侵袭性相关。我们之前的研究表明，LCN2 表达可以被 12-O-十四酰佛波醇-13-乙酸酯（TPA）通过五个核蛋白（MISP、KLF10、KLF15、PPP1R18 和 RXR）在食管鳞状细胞癌（ESCC）中诱导，在 5'侧翼区域的-152~-60bp 处结合到一个新的 TPA 反应元件（TRE）上。然而，对于这些蛋白是否可以响应 TPA 刺激来调节 LCN2 的反式激活，以及哪些细胞信号通路介导这一过程，还有很多未知。在这项研究中，编码这五个核蛋白的表达质粒被稳定转染到 EC109 细胞中。然后，通过双荧光素酶报告基因检测系统对稳定转染子进行了特征描述。应用 RT-PCR、实时 PCR、western blot、特定激酶抑制剂处理和生物信息学分析进行了研究。我们发现 MISP、KLF10、KLF15、PPP1R18 和 RXR 蛋白可以强烈响应 TPA 刺激并激活 LCN2 的转录表达。MEK、ERK、JNK 和 P38 激酶参与 LCN2 的反式激活。此外，MEK-ERK 信号通路在这个生物学过程中起着主要作用，但不涉及 PKC 信号。
