Department of Biological Sciences, National University of Singapore, Singapore, Singapore.
Sci Rep. 2019 Jul 23;9(1):10645. doi: 10.1038/s41598-019-46378-3.
Hepatocellular carcinoma (HCC) is one of the most severe cancer types and many genetic and environmental factors contribute to the development of HCC. Androgen receptor (AR) signaling is increasingly recognized as one of the important factors associated with HCC. Previously, we have developed an inducible HCC model in kras transgenic zebrafish. In the present study, to investigate the role of AR in liver tumor development, we specifically knocked out ar gene in the liver of zebrafish via the CRISPR/Cas9 system and the knockout zebrafish was named L-ARKO for liver-specific ar knockout. We observed that liver-specific knockout of ar attenuated liver tumor development in kras transgenic zebrafish at the early stage (one week of tumor induction). However, at the late stage (two weeks of tumor induction), essentially all kras transgenic fish continue to develop HCC irrespective of the absence or presence of ar gene, indicating an overwhelming role of the driver oncogene kras over ar knockout. Consistently, cell proliferation was reduced at the early stage, but not the late stage, of liver tumor induction in the kras/L-ARKO fish, indicating that the attenuant effect of ar knockout was at least in part via cell proliferation. Furthermore, androgen treatment showed acceleration of HCC progression in kras fish but not in kras/L-ARKO fish, further indicating the abolishment of ar signalling. Therefore, we have established a tissue-specific ar knockout zebrafish and it should be a valuable tool to investigate AR signalling in the liver in future.
肝细胞癌（HCC）是最严重的癌症类型之一，许多遗传和环境因素导致 HCC 的发生。雄激素受体（AR）信号通路被认为是与 HCC 相关的重要因素之一。先前，我们在 kras 转基因斑马鱼中开发了一种可诱导的 HCC 模型。在本研究中，为了研究 AR 在肝肿瘤发展中的作用，我们通过 CRISPR/Cas9 系统特异性敲除了斑马鱼肝脏中的 ar 基因，该敲除斑马鱼被命名为 L-ARKO（liver-specific ar knockout，肝脏特异性 ar 敲除）。我们观察到，在 kras 转基因斑马鱼中，肝脏特异性敲除 ar 基因在早期（肿瘤诱导后一周）减弱了肝肿瘤的发展。然而，在晚期（肿瘤诱导后两周），几乎所有的 kras 转基因鱼都继续发展为 HCC，无论是否存在 ar 基因，这表明驱动致癌基因 kras 的作用超过了 ar 敲除。一致地，在 kras/L-ARKO 鱼中，在肝肿瘤诱导的早期阶段而非晚期阶段，细胞增殖减少，表明 ar 敲除的抑制作用至少部分是通过细胞增殖实现的。此外，雄激素处理显示加速了 kras 鱼的 HCC 进展，但对 kras/L-ARKO 鱼没有加速作用，进一步表明 ar 信号通路的阻断。因此，我们建立了一种组织特异性的 ar 敲除斑马鱼，它应该是未来研究 AR 信号通路在肝脏中的一个有价值的工具。
