Vascular endothelial growth inhibitor 174 and its functional domains inhibit epithelial-mesenchymal transition in renal cell carcinoma cells in vitro

Abstract

The present study was carried out to investigate the effects of vascular endothelial growth inhibitor 174 (VEGI174) and its functional domains (V7 and V8) on epithelial‑mesenchymal transition (EMT) in renal cell carcinoma (RCC) cells in vitro. The RCC cell lines A498 and 786‑O were used in this study. Based on our preliminary study, we selected full‑length VEGI174 and its functional domains (V7 and V8) as the target genes in this study. Plasmids containing VEGI174, V7 or V8 transgenes were constructed and transfected into A498 and 786‑O cell lines. Cytological activity was tested during cell culture. Quantitative PCR and western blot analysis were performed to determine the expression levels of EMT markers (E‑cadherin, vimentin, β‑catenin and Slug). Overexpression of VEGI174, V7 or V8 did not have a significant influence on cell viability (P>0.05). The mRNA level of E‑cadherin was significantly upregulated, while that of vimentin was downregulated in A498VEGIexp, A498V7exp, A498V8exp, 786‑OVEGIexp, 786‑OV7exp and 786‑OV8exp cells compared with the cells containing the empty plasmid controls (P<0.05). The western blot results showed that changes in protein expression levels were consistent with the changes in mRNA expression. Both the mRNA and protein expression levels of β‑catenin and Slug were downregulated in the A498VEGIexp, A498V7exp, A498V8exp, 786‑OVEGIexp, 786‑OV7exp and 786‑OV8exp cells. In conclusion, overexpression of VEGI174, V7 or V8 inhibited EMT in A498 and 786‑O cells. Notably, V7 and V8 are two effective functional domains of VEGI174 that have the potential to be studied for peptide synthesis and the treatment of RCC.

VEGI174 protein and its functional domain peptides exert antitumour effects on renal cell carcinoma

“…In addition, Chew et al (14) demonstrated that overexpression of VEGI abrogates xenograft tumour progression by reducing tumour growth rate and microvessel density. It has also been demonstrated that overexpression of VEGI inhibits RCC cell motility, EMT, vascular endothelial tube formation and tumour growth (21)(22)(23)(24). Furthermore, VEGI participates in regulating the biological functions of several tumour cell lines, including breast carcinoma (MCF-7), cervical carcinoma (HeLa) and myeloid tumour (U-937 and ML-1a) cell lines (34,35).…”

“…The present study was approved by the ethics committee of Beijing Institute for Cancer Research (Beijing, China). Based on the human VEGI sequence (GenBank: NC_000009.12; https://www.ncbi.nlm.nih.gov/genbank/), eight different segments (V1-V8) were designed that encode the VEGI174 functional extracellular domains (23). In our prestudies, the full-length human VEGI174 and functional domain (V1-V8) genes were respectively cloned into mammalian expression plasmid vectors (pEF/His TOPO TA; Invitrogen; Thermo Fisher Scientific, Inc., Waltham, MA, USA) and were then transfected into human umbilical vein endothelial cells (HUVECs; American Type Culture Collection, Manassas, VA, USA).…”

“…VEGI is highly expressed in kidney, bladder, prostate, lung, breast and colon tissues (16)(17)(18)(19)(20)(21). Our previous studies revealed that overexpression of VEGI174 significantly inhibited RCC cell proliferation, motility, adhesion and epithelial-mesenchymal transition (EMT) in vitro and in vivo (21)(22)(23)(24). Taken together, these previous data suggested that VEGI174 exerts inhibitory effects on RCC; therefore, it may be valuable to be further study VEGI174 with regards to RCC treatment.…”