Functional Analysis of Serum Long Noncoding RNAs in Patients with Atrial Fibrillation.

Objectives: Long noncoding RNAs (lncRNAs) are closely related to diverse diseases. However, its role in atrial fibrillation (AF) pathogenesis needs further exploration. Design: We performed microarray analysis on the serum samples from 70 healthy volunteers and 70 AF patients. This study was aimed at detecting the levels of serum lncRNAs and mRNAs and bioinformatically analyze them to establish potential marker(s) for AF diagnosis. Receiver operating curve (ROC) and area under the curve (AUC) were employed to address the AF diagnostic power of lncRNAs. Results: In the AF serum samples, 753 lncRNAs and 802 mRNAs (p ≤ 0.05; fold change ≥ 2) were upregulated, and 315 lncRNAs and 153 mRNAs were downregulated, as opposed to healthy serum samples. Using bioinformatic analysis, we analyzed the top 4 differentially expressed (DE) lncRNAs, namely, NR-001587, NR-015407, NR-038455, and NR-038894, and found that the PI3K-AKT cell proliferation signaling pathway was most affected. This was in accordance with our functional analysis of DE mRNAs and adjacent lncRNAs. Notably, the elevated serum NR-001587 levels were strongly associated with AF incidence. Conclusions: Our work highlights the role of lncRNAs in AF pathogenesis and provides a novel serum biomarker for AF diagnosis.

Lipid metabolism in cancer progression and therapeutic strategies.

Dysregulated lipid metabolism represents an important metabolic alteration in cancer. Fatty acids, cholesterol, and phospholipid are the three most prevalent lipids that act as energy producers, signaling molecules, and source material for the biogenesis of cell membranes. The enhanced synthesis, storage, and uptake of lipids contribute to cancer progression. The rewiring of lipid metabolism in cancer has been linked to the activation of oncogenic signaling pathways and cross talk with the tumor microenvironment. The resulting activity favors the survival and proliferation of tumor cells in the harsh conditions within the tumor. Lipid metabolism also plays a vital role in tumor immunogenicity via effects on the function of the noncancer cells within the tumor microenvironment, especially immune-associated cells. Targeting altered lipid metabolism pathways has shown potential as a promising anticancer therapy. Here, we review recent evidence implicating the contribution of lipid metabolic reprogramming in cancer to cancer progression, and discuss the molecular mechanisms underlying lipid metabolism rewiring in cancer, and potential therapeutic strategies directed toward lipid metabolism in cancer. This review sheds new light to fully understanding of the role of lipid metabolic reprogramming in the context of cancer and provides valuable clues on therapeutic strategies targeting lipid metabolism in cancer.

Insulin-like growth factor 1-induced enolase 2 deacetylation by HDAC3 promotes metastasis of pancreatic cancer.

Enolase 2 (ENO2) is a key glycolytic enzyme in the metabolic process of glycolysis, but its potential function in pancreatic ductal adenocarcinoma (PDAC) is unclear. In this study, we observed a significant overexpression of ENO2 in PDAC tissues, and its expression was correlated with metastasis and poor prognosis in PDAC patients. K394 was identified as a major acetylation site in ENO2 that regulates its enzymatic activity, cell metabolism and PDAC progression. Knockdown of ENO2 suppressed tumor growth and liver metastasis in PDAC. Re-expression of wild-type (WT) ENO2, but not the K394 acetylation mimetic mutant, could reverse the decreased tumor malignancy. We further characterized histone deacetylase 3 (HDAC3) and P300/CBP-associated factor (PCAF) as the potential deacetylase and acetyltransferase for ENO2, respectively. HDAC3-mediated deacetylation was shown to lead to ENO2 activation and enhancement of glycolysis. Importantly, insulin-like growth factor-1 (IGF-1) was found to decrease K394 acetylation and stimulate ENO2 activity in a dose- and time-dependent manner. The PI3K/AKT/mTOR pathway facilitated the phosphorylation of HDAC3 on S424, which promoted K394 deacetylation and activation of ENO2. Linsitinib, an oral small-molecule inhibitor of IGF-1R, could inhibit IGF-1-induced ENO2 deacetylation by HDAC3 and the PI3K/AKT/mTOR pathway. Furthermore, linsitinib showed a different effect on the growth and metastasis of PDAC depending on the overexpression of WT versus K394-mutant ENO2. Our results reveal a novel mechanism by which acetylation negatively regulates ENO2 activity in the metastasis of PDAC by modulating glycolysis. Blockade of IGF-1-induced ENO2 deacetylation represents a promising strategy to prevent the development of PDAC.

STMN1 upregulation mediates hepatocellular carcinoma and hepatic stellate cell crosstalk to aggravate cancer by triggering the MET pathway.

STMN1 has been regarded as an oncogene and its upregulation is closely associated with malignant behavior and poor prognosis in multiple cancers. However, the detailed functions and underlying mechanisms of STMN1 are still largely unknown in hepatocellular carcinoma (HCC) development. Herein, we analyzed STMN1 expression and the related clinical significance in HCC by using well-established Protein Atlas, The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cancer databases. Analysis indicated that STMN1 was highly expressed in HCC and closely associated with vascular invasion, higher histological grade, advanced clinical grade and shorter survival time in HCC patients. Overexpressing and silencing STMN1 in HCC cell lines showed that STMN1 could regulate cell proliferation, migration, drug resistance, cancer stem cell properties in vitro as well as tumor growth in vivo. Further experiments showed that STMN1 mediated intricate crosstalk between HCC and hepatic stellate cells (HSC) by triggering the hepatocyte growth factor (HGF)/MET signal pathway. When HSC were cocultured with HCC cells, HSC secreted more HGF to stimulate the expression of STMN1 in HCC cells. Mutually, STMN1 upregulation in HCC cells facilitated HSC activation to acquire cancer-associated fibroblast (CAF) features. The MET inhibitor crizotinib significantly blocked this crosstalk and slowed tumor growth in vivo. In conclusion, our findings shed new insight on STMN1 function, and suggest that STMN1 may be used as a potential marker to identify patients who may benefit from MET inhibitor treatment.

Osteopontin promotes metastasis of intrahepatic cholangiocarcinoma through recruiting MAPK1 and mediating Ser675 phosphorylation of ß-Catenin.

The incidence and mortality of intrahepatic cholangiocarcinoma (ICC) are increasing worldwide in recent decades. Osteopontin (OPN) plays an important role in cancer metastasis, but its functional mechanism in ICC is not clear yet. In this study, we found that OPN level was elevated both in plasma and tumor tissues of ICC patients, which was closely related to a shorter overall survival (OS) and high probability of tumor relapse after curative resection. The gain- and loss-of-function studies determined that OPN could promote ICC growth and metastasis. OPN selectively interacted with ß-Catenin and knockdown of ß-Catenin abrogated the effects induced by OPN. OPN recruited MAPK1 and activated MEK-MAPK1 pathway to mediate the S675 phosphorylation of ß-Catenin and nucleus accumulation, which induced the activation of Wnt signaling. Moreover, a significant correlation between OPN and ß-Catenin was found in ICC tissues. OPN, ß-Catenin, and their combination were independent prognostic indicator for ICC patients. In conclusion, OPN promotes ICC progression through recruiting MAPK1 and activating the Wnt/ß-Catenin pathway and can serve as a novel prognostic marker and therapeutic target for ICC.