Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China.
Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Cell Death Dis. 2020 May 7;11(5):337. doi: 10.1038/s41419-020-2541-x.
Zinc fingers and homeoboxes 2 (ZHX2) was found as a novel VHL substrate target, and acted as an oncogenic driver in ccRCC. However, the detailed mechanism of ZHX2 in ccRCC development remains elusive, and no research has focused on studying ZHX2 in drug resistance yet. A tissue microarray with 358 ccRCC samples was used to determine the expression of ZHX2 in ccRCC patients. VHL-deficient cell line 786-O and VHL-normal cell line CAKI-1 was used for lineage reprogramming by transfecting with lentivirus. The in vitro and in vivo experiments were performed with these new cell lines to determine the mechanism of ZHX2 in ccRCC development and drug resistance. Immunohistochemistry analysis showed that ZHX2 was not highly expressed in ccRCC tumor tissues, only 33.2% (119/358) patients have high ZHX2 expression. However, high ZHX2 was significantly associated with advanced Fuhrman grade (p = 0.004), and proved to be an independent prognosis factor for progression-free survival (p = 0.0003), while there is no significant correlation with overall survival. We further discovered that ZHX2 overexpression could increase VEGF secretion and transcriptional activate the MEK/ERK1/2 and promote its downstream targets. We also found ZHX2 overexpression induce Sunitinib resistance though activating autophagy and the combination treatment of Sunitinib and Chloroquine could significantly rescue the phenomenon. In summary, these results indicate that ZHX2 drivers cell growth, migration though increase VEGF expression, and transcriptional activate MEK/ERK1/2 signaling pathway, and could induce Sunitinib resistance by regulating self-protective autophagy, these may provide new insight in advanced ccRCC treatment.
锌指和同源盒 2（ZHX2）被发现是一种新型的 VHL 底物靶标，并在 ccRCC 中充当致癌驱动因子。然而，ZHX2 在 ccRCC 发展中的详细机制仍然难以捉摸，并且没有研究专注于研究 ZHX2 在耐药性方面的作用。使用包含 358 例 ccRCC 样本的组织微阵列来确定 ccRCC 患者中 ZHX2 的表达。使用 VHL 缺陷细胞系 786-O 和 VHL 正常细胞系 CAKI-1 通过转染慢病毒进行谱系重编程。使用这些新细胞系进行体外和体内实验，以确定 ZHX2 在 ccRCC 发展和耐药性中的作用机制。免疫组织化学分析表明，ZHX2 在 ccRCC 肿瘤组织中表达不高，只有 33.2%（119/358）的患者有高 ZHX2 表达。然而，高 ZHX2 与高级 Fuhrman 分级显著相关（p=0.004），并被证明是无进展生存期的独立预后因素（p=0.0003），而与总生存期无显著相关性。我们进一步发现，ZHX2 过表达可以增加 VEGF 的分泌，并转录激活 MEK/ERK1/2 及其下游靶标。我们还发现，ZHX2 过表达通过激活自噬诱导舒尼替尼耐药，而舒尼替尼和氯喹联合治疗可以显著挽救这种现象。总之，这些结果表明，ZHX2 通过增加 VEGF 表达驱动细胞生长和迁移，并转录激活 MEK/ERK1/2 信号通路，通过调节自保护自噬诱导舒尼替尼耐药，这可能为晚期 ccRCC 的治疗提供新的思路。
