Evaluation of the antiangiogenic activity of zinc in renal adenocarcinoma in a hypoxic microenvironment

Abstract

Renal cancer is a common urologic malignancy, and therapeutic options for metastatic disease are limited. Most clear cell renal cell carcinomas (ccRCC) are associated with loss of Von Hippel-Lindau tumor suppressor (VHL) function and deregulation of hypoxia pathways. This deregulation induces angiogenesis, promoting tumor growth and metastasis. Vascular endothelial growth factor (VEGF), a pro-angiogenic factor, is overexpressed in ccRCC, contributing to its aggressive nature. Zinc (Zn), an essential micronutrient, has garnered attention for its potential in cancer therapy. While Zn deficiency increases cancer risk, Zn supplementation exhibits anticancer effects, inhibiting proliferation and migration of some types of cancer. However, conflicting evidence regarding Zn's association with RCC necessitates further research to elucidate its role in renal carcinogenesis. This study aimed to evaluate the effect of Zinc Chloride on angiogenesis regulator genes in ccRCC under normoxic and hypoxic conditions. The MTS (3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium-bromide) assay was used to define cell viability of different Zn concentrations on ccRCC cells. The expression of HIF-1a and VEGF-a genes from the 786-0, 786-0 + Zn, 786-0 hypoxia and 786-0 hypoxia + Zn samples was evaluated by RT-qPCR and Western blot. Cell viability assays demonstrated that 100mM of Zn on ccRCC cells showed a significant inhibitory effect. Gene expression analysis by RT-qPCR comparing 786-0 with and without Zn supplementation, under normoxia and hypoxia conditions, showed decreased levels of HIF-1a - 73.75 ± 20.32% (P<0.001 vs. 786-0); 67.99 ± 4.26% (P<0.001 vs. 786-0 hypoxia) and VEGF-a - 60.72 ± 17.58% (P<0.05 vs. 786-0); 56.62 ± 8.07% (P<0.05 vs. 786-0 hypoxia). Western Blot data corroborated the RT-qPCR results. Zinc Chloride demonstrates an antiangiogenic potential in ccRCC cells. Additional experiments are going to be done to comprehensively understand the pathophysiological mechanisms of Zinc Chloride as a novel treatment for ccRCC.