ZHX2 drives cell growth and migration via activating MEK/ERK signal and induces Sunitinib resistance by regulating the autophagy in clear cell Renal Cell Carcinoma

Liangsong Zhu,Hao Yan,Zongming Lin,Jin Zhang,Rong Ding

doi:10.1038/s41419-020-2541-x

Abstract

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.

Highlights

Introduction Since the tumor suppressor geneVHL was identified as the key point of the Von Hippel-Lindau (VHL) disease in 19931, it has been clearly proved that hypoxia or geneOfficial journal of the Cell Death Differentiation AssociationZhu et al Cell Death and Disease (2020)11:337(ccRCC), and the tyrosine kinase inhibitors (TKIs) that target the VHL substrate hypoxia-inducible factors (HIFs) signal have showed treating benefit in patients with advanced ccRCC
The prognostic analysis showed that the patients with high Zinc fingers and homeoboxes 2 (ZHX2) have worse progression-free survival (PFS) while there was no significant relation with overall survival (OS) (Fig. 1b, c)
Univarivate and multivariate Cox regression analysis showed the higher expression of ZHX2 had independent predictive value for PFS in ccRCC patients. (HR = 0.567, p = 0.035, Supplementary Table S3–S4), which means ZHX2 might act as a tumor promoter that contributed to occurrence and recurrence of ccRCC

Summary

Introduction

Introduction Since the tumor suppressor geneVHL was identified as the key point of the Von Hippel-Lindau (VHL) disease in 19931, it has been clearly proved that hypoxia or geneOfficial journal of the Cell Death Differentiation AssociationZhu et al Cell Death and Disease (2020)11:337(ccRCC), and the tyrosine kinase inhibitors (TKIs) that target the VHL substrate HIF signal have showed treating benefit in patients with advanced ccRCC. Qing Zhang et al.[12] have found that Zinc fingers and homeoboxes 2 (ZHX2) is a novel VHL substrate transcription factor by using a genome-wide human cDNA library strategy; and they reported that depletion of ZHX2 could inhibit the proliferation of VHL-deficient ccRCC cell lines through impairing NF-κB pathway. Lv et al.[16] demonstrated that ZHX2 promoter region was hypermethylated in hepatocellular carcinoma (HCC) samples, suggesting it might functions as a tumor suppressor. Another immunohistochemical research reported that ZHX2 was highly expressed in tumor samples compared to adjacent tissues in HCC patients, and the prognostic analysis showed ZHX2 was associated with poorer outcomes[17], seems it act as an oncogenic biomarker

Methods

Results

Conclusion