UTRN inhibits melanoma growth by suppressing p38 and JNK/c-Jun signaling pathways

Sitong Zhou,Xi Zhang,Huaiyuan Xu,Baiqiang Mei,Shijian Xiang,Lexi Liao,Ronghua Yang,Wen Ouyang,Jiehua Li,Xiaobing Pi

doi:10.1186/s12935-021-01768-4

Abstract

BackgroundUtrophin (UTRN), as a tumor suppressor gene, is involved in various cancer progression. The function of UTRN in the melanoma process and the related molecular mechanisms are still unclear. Herein, we studied the function of UTRN in melanoma growth and the relevant molecular mechanisms.MethodsUsing the GEO database and UCSC Xena project, we compared the expression of UTRN in non-cancerous and melanoma tissues. Immunohistochemistry (IHC) staining, qRT-PCR and Western Blot (WB) were performed to evaluate UTRN expression in clinical samples. A total of 447 cases with UTRN expression data, patient characteristics and survival data were extracted from TCGA database and analyzed. After stable transduction and single cell cloning, the proliferation ability of A375 human melanoma cells was analyzed by Cell Counting Kit‑8 (CCK) and 5‑ethynyl‑2′‑deoxyuridine (EdU) incorporation assays. GSEA was performed to predict the mechanism by which UTRN regulated melanoma growth. Then WB analysis was used to assess the protein expression levels of pathway signaling in overexpression (EXP) melanoma cells. Epac activator 8-pCPT-2′-O-Me-cAMP was then used to evaluate the proliferation ability by activation of p38 and JNK/c-Jun signaling pathways.ResultsData from GEO and UCSC Xena project indicated that UTRN expression was decreased in melanoma. Experiment on clinical samples further confirmed our finding. TCGA results showed that a reduced expression of UTRN in 447 melanoma samples was associated with advanced clinical characteristics (T stage, Clark level, ulceration), shorter survival time and poorer prognosis. In addition, up-regulated UTRN expression inhibited melanoma cell proliferation when compared to control group. MAPK signaling pathway was presented in both KEGG and BioCarta databases by using GSEA tool. WB results confirmed the down-regulated expression of p38, JNK1 and c-Jun in EXP group when compared to control group. Epac activator 8-pCPT-2′-O-Me-cAMP treatment could partially rescue proliferation of tumor cells.ConclusionWe have demonstrated that reduced UTRN predicted poorer prognosis and UTRN inhibited melanoma growth via p38 and JNK1/c-Jun pathways. Therefore, UTRN could serve as a tumor suppressor and novel prognostic biomarker for melanoma patients.

Highlights

Utrophin (UTRN), as a tumor suppressor gene, is involved in various cancer progression
Decreased UTRN expression in melanoma To evaluate UTRN expression in melanoma tissues, we first analyzed UTRN mRNA expression from Gene Expression Omnibus (GEO) database (GSE3189) (Fig. 1a) and UCSC XENA platform (Fig. 1b). These data showed that UTRN mRNA level was significantly lower in melanoma compared with mRNA level in nevus tissues and normal skin
Bioinformatic analysis demonstrated that decreased expression of UTRN in melanoma was associated with advanced clinical characteristic (T stage, Clark level, ulceration), lower survival time and poorer prognosis

Summary

Introduction

Utrophin (UTRN), as a tumor suppressor gene, is involved in various cancer progression. The function of UTRN in the melanoma process and the related molecular mechanisms are still unclear. We studied the function of UTRN in melanoma growth and the relevant molecular mechanisms. Survival rate was associated with tumor characteristics such as Clark level, ulceration and lymph node involvement [4,5,6]. The expression level of UTRN depends on cell type and tumor. UTRN was found to be significantly decreased and associated with progression in lung cancer and colon cancer, which indicated that UTRN could be a potential tumor suppressor gene [7]. The link between UTRN and clinical outcome as well as the molecular functional role of UTRN in melanoma have not been made clear

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