Clinical Skills Learning Center, School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R. China.
Mol Med Rep. 2013 Oct;8(4):1017-22. doi: 10.3892/mmr.2013.1643. Epub 2013 Aug 16.
In this study, we aimed to investigate changes in the expression of human Clock (hClock), a gene at the core of the circadian gene family, in colorectal carcinomas (CRCs) and to discuss the possible effects. Previous studies have revealed that the disruption of circadian rhythms is one of the endogenous factors that contribute to the initiation and development of CRCs. However, the underlying molecular changes to the circadian genes associated with CRCs have not been explored. Immunofluorescence and quantitative polymerase chain reaction (qPCR) analysis of the hCLOCK protein and gene expression were performed in 30 cases of CRC. The hCLOCK protein was expressed in all specimens obtained from 30 CRC patients. Higher levels of hCLOCK expression were observed in human CRC tissues compared with the paired non-cancerous tissues. hCLOCK expression was significantly higher in poorly differentiated, or late-stage, Dukes' grade tumors and in 64.3% of tumor cases with lymph node metastasis. The hClock gene was expressed in all specimens. A significantly higher expression of hClock was found in human CRC cases compared with paired non-cancerous tissues. There was a strong positive linear correlation between hClock gene expression and protein expression in human CRCs. A strong positive linear correlation was also found between hClock gene expression and ARNT, HIF-1α and VEGF expression in human CRCs. There was no significant correlation between hClock and Bak, Bax, Bid, tumor necrosis factor receptor I (TNFR I) and TNFR II. The circadian gene hClock was stably expressed in human colorectal mucosa and was important in regulating the expression of downstream clock-controlled genes. hCLOCK may interact with HIF-1α/ARNT and activate VEGF to stimulate tumor angiogenesis and metastasis.
在这项研究中，我们旨在研究核心生物钟基因家族中的人类时钟（hClock）基因在结直肠癌（CRC）中的表达变化，并探讨其可能的影响。先前的研究表明，昼夜节律紊乱是CRC 发生和发展的内在因素之一。然而，与 CRC 相关的生物钟基因的潜在分子变化尚未得到探索。我们对 30 例 CRC 患者的 hCLOCK 蛋白和基因表达进行了免疫荧光和定量聚合酶链反应（qPCR）分析。hCLOCK 蛋白在 30 例 CRC 患者的所有标本中均有表达。与配对的非癌组织相比，人 CRC 组织中 hCLOCK 的表达水平更高。hCLOCK 表达在分化差、晚期 Dukes' 级肿瘤和 64.3%有淋巴结转移的肿瘤病例中显著更高。hClock 基因在所有标本中均有表达。与配对的非癌组织相比，人 CRC 病例中 hClock 的表达明显更高。hClock 基因在人 CRC 中的表达与蛋白表达之间存在很强的正线性相关性。hClock 基因在人 CRC 中的表达与 ARNT、HIF-1α 和 VEGF 的表达之间也存在很强的正线性相关性。hClock 与 Bak、Bax、Bid、肿瘤坏死因子受体 I（TNFR I）和 TNFR II 之间没有显著相关性。昼夜节律基因 hClock 在人结直肠黏膜中稳定表达，在调节下游时钟控制基因的表达中起重要作用。hCLOCK 可能与 HIF-1α/ARNT 相互作用并激活 VEGF，从而刺激肿瘤血管生成和转移。
