miR-4417 Targets Tripartite Motif-Containing 35 (TRIM35) and Regulates Pyruvate Kinase Muscle 2 (PKM2) Phosphorylation to Promote Proliferation and Suppress Apoptosis in Hepatocellular Carcinoma Cells

Abstract

BackgroundMicroRNAs (miRNAs) are a class of small non-coding RNAs that are strongly involved in various types of carcinogenesis, including hepatocellular carcinoma (HCC). This study aimed to clarify whether miR-4417 promotes HCC growth by targeting TRIM35 and regulating PKM2 phosphorylation.Material/MethodsOnline software, including TargetScan and miRanda, was used to predict the potential target of miR-4417. Real-Time PCR (qRT-PCR) and Western blot assays were performed to detect the expression levels of mRNA and protein, respectively. Cell proliferation was measured by MTT assay and apoptosis in A549 cells was examined by flow cytometry.ResultsBioinformatics reveal that TRIM35 mRNA contains 1 conserved target site of miR-4417. High level of miR-4417 and low levels of TRIM35 mRNA and protein were observed in HCC cells compared with a normal liver cell line. Biological function analysis showed that miR-4417 inhibitor inhibits cell proliferation and promotes apoptosis in HCC cells. Furthermore, we verified that TRIM35 is a functional target of miR-4417 by use of luciferase reporter assay, and TRIM35 overexpressing showed an elevation of proliferation and a reduction of apoptosis in HCC cells. We subsequently investigated whether miR-4417 and TRIM35 regulate HCC cell proliferation and apoptosis through PKM2 Y105 phosphorylation, and the results supported our speculation that miR-4417 targets TRIM35 and regulates the Y105 phosphorylation of PKM2 to promote hepatocarcinogenesis.ConclusionsOur findings indicate that miR-4417 may function as an oncogene in HCC and is a potential alternative therapeutic target for this deadly disease.

PKM2, function and expression and regulation

“…Similar to: miRNA-29b [89], miRNA-99a [90], miRNA-133b [91], miRNA-145 [92], miRNA-148a [93], miRNA-152 [93, 94], miRNA-290 [95], miRNA-326 [96], miRNA-338-3P [97], miRNA-340 [98], miRNA-369 [99], miRNA-371 [95], miR-379 [100], miRNA-675 [101], miRNA-4417 etc. [102]. While these miRNAs are targeted to the splicing factors PTBP1, hnRNPA1, and hnRNPA2, [103] the expression of PKM mRNA is shifted from PKM1 to PKM2, and the expression of PKM2 is increased [104].…”

Bioinformatics identification of microRNAs involved in�polycystic ovary syndrome based on microarray data

“…In addition, a previous study revealed that OTU deubiquitinase 5 suppression via hsa-miR-4417 and hsa-miR-6782 could maintain the viability of tumor cells and suppress programmed cell death (52). Song et al (53) demonstrated that, in hepatocellular carcinoma cells, miR-4417 can promote proliferation and suppress apoptosis by targeting tripartite motif-containing 35 and regulating the phosphorylation of pyruvate kinase muscle. Furthermore, the present study identified 935 target genes using four databases.…”

Roles of Thyroid Hormone-Associated microRNAs Affecting Oxidative Stress in Human Hepatocellular Carcinoma

“…One possibility is that the thyroid hormone induces miR-214 to suppress Bim expression through negatively regulating the transcription factor Forkhead box protein O1 (FoxO1) to avoid liver cell apoptosis and ROS-induced stress [110]. In addition to miR-214, there are many miRNAs that have the potential to affect the apoptosis of liver cancer cells, such as miR-155, miR-4417, miR-199a, and miR-122 [59,77,115,116]. Among them, the expression levels of miR-199a and miR-122 are associated with thyroid hormone and oxidative stress (Table 2 and Table 3) [27].…”