Are Ski and SnoN Involved in the Tumorigenesis of Oral Squamous Cell Carcinoma Through Smad4?

MicroRNA-195-5p inhibits the progression of hemangioma via targeting SKI

Hemangioma (HA), which is characterized by aberrant endothelial cell proliferation in blood vessels, is a common tumor during infancy. MicroRNAs (miRNAs/miRs) collectively participate in the development of HA; however, the potential roles of miR-195-5p in HA are not completely understood. The aim of the present study was to investigate the roles of miR-195-5p in HA. In the present study, miR-195-5p was found to be downregulated in HA cells, such as the XPTS-1 human infantile hemangioma-derived endothelial cell line and the EOMA hemangioendothelioma cell line. Overexpression of miR-195-5p was shown to suppress HA cell viability, colony formation and proliferation, and induced HA cell apoptosis. Furthermore, miR-195-5p downregulated Bcl-2 expression and upregulated Bax and Bcl-2 expression levels. V-ski sarcoma viral oncogene homolog (SKI) was identified as a target of miR-195-5p. Co-transfection of miR-195-5p mimics and SKI 3'-untranslated region wild-type decreased HA cell luciferase activity. SKI overexpression alleviated the miR-195-5p-induced decrease in HA cell proliferation and increased HA cell apoptosis. In addition, the regulatory role of miR-195-5p on the expression of Bcl-2, Bax and poly(ADP-ribose) polymerase was reversed by SKI. Collectively, the results of the present study demonstrated that miR-195-5p suppressed HA progression and its effects were mediated via SKI. Therefore, the miR-195-5p/SKI axis may represent a novel therapeutic target for HA.

Ski: Double roles in cancers

The Ski (Sloan-Kettering Institute) is an evolutionarily conserved protein that plays a dual role as an oncoprotein and tumor suppressor gene in the development of human cancer. The Ski oncogene was first identified as a transforming protein of the avian Sloan-Kettering retrovirus in 1986. Since its discovery, Ski has been identified as a carcinogenic regulator in a variety of malignant tumors. Later, it was reported that Ski regulates the occurrence and development of some cancers by acting as an oncogene. Ski mediates the proliferation, differentiation, metastasis, and invasion of numerous cancer cells through various mechanisms. Several studies have shown that Ski expression is correlated with the clinical characteristics of cancer patients and is a promising biomarker and therapeutic target for cancer. In this review, we summarize the mechanisms and potential clinical implications of Ski in dimorphism, cancer occurrence, and progression in various types of cancer.