Identification and characterization of a novel peptide interacting with cAMP-responsive elements binding and cAMP-responsive elements modulator in mouse liver

A Novel Biomarker Driving Poor-Prognosis Liver Cancer: Overexpression of the Mitochondrial Calcium Gatekeepers

Several studies have indicated the biological role of mitochondrial Ca²⁺ uptake in cancer pathophysiology; however, its implications in predicting the prognosis of hepatocellular carcinoma (HCC) are not yet fully understood. Here, we collected tumor specimens and adjacent normal liver tissues from 354 confirmed HCC patients and analyzed the levels of cyclic adenosine monophosphate (cAMP) responsive element binding protein 1 (CREB), mitochondrial calcium uniporter (MCU), mitochondrial calcium uptake 1 and 2 (MICU1, MICU2) using bioinformatics, qRT-PCR, and immunohistochemistry (IHC), and their relationship with clinicopathological characteristics and prognosis. HCC patients with low CREB/MICU1 and high MCU/MICU2 expression exhibited poor survival rate and prognosis in overall survival (OS) and disease-free survival (DFS) analyses. Low CREB/MICU1 and low MICU1 alone indicated poor prognosis in stage I/II and III/IV patients, respectively. In the poor differentiation/undifferentiation group, low expression of MICU1 indicated poor clinical outcomes. Low CREB/MICU1 expression suggested poor outcomes in patients with or without hepatitis B virus (HBV) infection and poor prognosis in the HCV infection group. In the non- hepatitis C virus (HCV) infection group, low MCU1 indicated a poor prognosis. Multivariate analysis demonstrated that CREB and MICU1 expression showed prognostic significance. This study demonstrates the prognostic significance of CREB, MCU, MICU1, and MICU2, in predicting HCC outcomes. Low CREB/MICU1 and high MCU/MICU2 in HCC tissues are associated with poor prognosis, thus offering a novel perspective in the clinical management for HCC patients.

Overexpression of activating transcription factor 3 exerts suppressive effects in HepG2 cells

The present study observed and compared the biological behaviour of HepG2 cells prior and subsequent to the overexpression of activating transcription factor 3 (ATF3). Experiments investigating the cytological function by which ATF3 affects liver cancer cells were also performed. MTT, Transwell and flow cytometry assays were used to observe and detect the biological behaviour of HepG2 cells with and without lentivirus (LV)-ATF3-enhanced green fluorescent protein (EGFP) infection. The effects of ATF3 overexpression on cell proliferation, migration, apoptosis and cell cycle progression were evaluated. The LV-ATF3-EGFP overexpression vector was successfully constructed, and the HepG2 cells were successfully infected with the vector. Following ATF3 overexpression, cell proliferation was decreased, the rate of cell apoptosis was accelerated and cell cycle progression was slowed (P<0.05). There were no marked changes in cell migration (P>0.05), although there was a trend towards a gradual decrease. In conclusion, ATF3 exerted suppressive effects in HepG2 cells, potentially by inhibiting cancer cell growth, accelerating cell apoptosis, and blocking cell cycle progression. Intervention targeting ATF3 expression may represent a novel approach for the prevention and treatment of human liver cancer.

Hepatocyte odd protein shuttling (HOPS) is a bridging protein in the nucleophosmin-p19 Arf network

Nucleophosmin (NPM), a ubiquitously and abundantly expressed protein, occurs in the nucleolus, shuttling between the nucleoplasm and cytoplasm. The NPM gene is mutated in almost 30% of human acute myeloid leukemia cells. NPM interacts with p53 and p19(Arf), directs localization of p19(Arf) in the nucleolus and protects the latter from degradation. Hepatocyte odd protein shuttling (HOPS) is also a ubiquitously expressed protein that moves between the nucleus and cytoplasm. Within the nucleus of resting cells, HOPS overexpression causes cell cycle arrest in G0/G1. HOPS knockdown causes centrosome hyperamplification leading to multinucleated cells and the formation of micronuclei. We demonstrate a direct interaction of HOPS with NPM and p19(Arf), resulting in a functionally active trimeric complex. NPM appeared to regulate HOPS half-life, which, in turn, stabilized p19(Arf) and controlled its localization in the nucleolus. These findings suggest that HOPS acts as a functional bridge in the interaction between NPM and p19(Arf), providing new mechanistic insight into how NPM and p19(Arf) will oppose tumor cell proliferation.