MESP1-knockdown inhibits the proliferation and epithelial mesenchymal transition of hepatocellular carcinoma and enhances the tumor-suppressive effect of 5-fluorouracil

Primary liver hepatocellular carcinoma (HCC) is the third most deadly malignancy worldwide,in part, because it is often diagnosed at an advanced stage. Thus, molecular markers are needed to aid in the early diagnosis and treatment of HCC. Expression of abnormal mesoderm posterior-1 (MESP1) promotes tumorigenesis; however,its role in the regulation of HCC proliferation, apoptosis,and invasion is unknown. Here,we analyzed data in The Cancer Genome Atlas (TCGA)and Genotype Tissue Expression (GTEx) databases on the pan-cancer expression of MESP1 and its relationship with clinical characteristics and prognosis of patients with HCC. The expression of MESP1 was measured in 48 HCC tissues using immunohistochemical staining,and the results were correlated with clinical stage, tumor differentiation, tumor size,and metastasis. MESP1 expression was downregulated using small interfering RNA (siRNA) in the HCC cell lines HepG2 and Hep3B,and cell viability, proliferation,cell cycle, apoptosis,and invasion were analyzed. Finally,we also evaluated the tumor suppression effect of MESP1 downregulation combined with 5-fluorouracil (5-FU) treatment. Our results showed that MESP1 is a pan-oncogene associated with poor prognosis in patients with HCC. siRNA-induced downregulation of MESP1 expression in HepG2 and Hep3B cells exhibited downregulation of β-catenin and GSK3β expression 48h after transfection, along with an increase in apoptosis rate, arrest in the G1-S phase,and a decrease in mitochondrial membrane potential. Moreover,the expression levels of c-Myc, PARP1, bcl2, Snail1, MMP9, and immune checkpoint genes (TIGIT, CTLA4,LAG3,CD274,and PDCD1) were downregulated, while those of caspase3 and E-cadherin were upregulated. Tumor cells also showed decreased migration ability. Furthermore, siRNA interference of MESP1 expression combined with 5-FU-treatment of HCC cells significantly enhanced the G1-S phase block and apoptosis. MESP1 showed an aberrant high expression in HCC and was associated with poor clinical outcomes; therefore, MESP1 may be a potential target for the diagnosis and treatment of HCC.