BackgroundLiver tumor initiating cells (TICs) have self-renewal and differentiation properties, accounting for tumor initiation, metastasis and drug resistance. Long noncoding RNAs are involved in many physiological and pathological processes, including tumorigenesis. DNA copy number alterations (CNA) participate in tumor formation and progression, while the CNA of lncRNAs and their roles are largely unknown.MethodsLncRNA CNA was determined by microarray analyses, realtime PCR and DNA FISH. Liver TICs were enriched by surface marker CD133 and oncosphere formation. TIC self-renewal was analyzed by oncosphere formation, tumor initiation and propagation. CRISPRi and ASO were used for lncRNA loss of function. RNA pulldown, western blot and double FISH were used to identify the interaction between lncRNA and CTNNBIP1.ResultsUsing transcriptome microarray analysis, we identified a frequently amplified long noncoding RNA in liver cancer termed linc00210, which was highly expressed in liver cancer and liver TICs. Linc00210 copy number gain is associated with its high expression in liver cancer and liver TICs. Linc00210 promoted self-renewal and tumor initiating capacity of liver TICs through Wnt/β-catenin signaling. Linc00210 interacted with CTNNBIP1 and blocked its inhibitory role in Wnt/β-catenin activation. Linc00210 silencing cells showed enhanced interaction of β-catenin and CTNNBIP1, and impaired interaction of β-catenin and TCF/LEF components. We also confirmed linc00210 copy number gain using primary hepatocellular carcinoma (HCC) samples, and found the correlation between linc00210 CNA and Wnt/β-catenin activation. Of interest, linc00210, CTNNBIP1 and Wnt/β-catenin signaling targeting can efficiently inhibit tumor growth and progression, and liver TIC propagation.ConclusionWith copy-number gain in liver TICs, linc00210 is highly expressed along with liver tumorigenesis. Linc00210 drives the self-renewal and propagation of liver TICs through activating Wnt/β-catenin signaling. Linc00210 interacts with CTNNBIP1 and blocks the combination between CTNNBIP1 and β-catenin, driving the activation of Wnt/β-catenin signaling. Linc00210-CTNNBIP1-Wnt/β-catenin axis can be targeted for liver TIC elimination.

Background: To investigate the role of focal adhesion kinase (FAK)-mediated signaling in hypoxia-induced cardiac fibroblasts (CFs) differentiation and cardiac fibrosis post-myocardial infarction (MI) on a mice model. Methods: CFs of neonatal C57BL/6 mice were treated under normoxic, hypoxic, or hypoxic+PP2 (known as a Src kinase family inhibitor) conditions. Gene expressions of FAK, alpha-smooth muscle actin (α-SMA) and collagen type I alpha 1 (Col1α1), or α-SMA and vimentin levels were performed by RT-PCR and immunofluorescence staining, respectively. Thirty mice were surgically treated into Sham (n=7) and MI (n=23) groups; and FAK inhibitor PF-562271 was given to six survivor MI mice (as PF group, from 15 survivors). Heart function and collagenous tissues were examined by echocardiography, as well as by Masson‘s trichrome and Sirius red staining, respectively. Type I collagen, FAK protein, mTOR, ERK1/2, AKT, P70S6K and phospho-FAK levels were also analyzed. Results: FAK inhibition with PP2 significantly decreased CFs differentiation and collagen synthesis under hypoxia treatment. In vivo, PF-562271 treatment resulted in fibrosis attenuation; however, deteriorated heart function of MI mice could not be significantly improved. PF-562271 may affect phospho-mTOR (p<0.05), phospho-ERK1/2 (p<0.01), phospho-AKT (p<0.001) and phospho-P70S6K (p<0.05) to exert its benefits. FAK can be activated either under hypoxia in CFs or MI in a mouse model to promote fibrosis. However, pharmacological inhibition of FAK can attenuate fibrosis response. Conclusion: This study provides novel evidence that FAK inhibition may become a promising pharmaceutical strategy to attenuate fibrosis post-MI.

Objectives: To investigate ghrelin levels in patients with idiopathic pulmonary arterial hypertension (IPAH) and the association of ghrelin with N-terminal brain natriuretic peptide (N-BNP), endothelin-1 (ET-1) and nitric oxide (NO). Methods: Plasma ghrelin, N-BNP, ET-1 and NO were measured, and echocardiography was performed in 20 IPAH patients and in 20 control subjects matched for age, sex and body mass index. Results: Plasma ghrelin and NT-proBNP levels were significantly higher in IPAH patients compared with values in control subjects (p < 0.05). In IPAH patients, ghrelin levels correlated positively with N-BNP (r = 0.616, p = 0.004), NO (r = 0.464, p = 0.039), right ventricle diameter (RVD; r = 0.485, p = 0.030) and pulmonary arterial systolic pressure (PASP; r = 0.591, p = 0.006). N-BNP levels correlated positively with RVD (r = 0.551, p = 0.012) and ET-1 (r = 0.451, p = 0.046). Conclusions: Plasma ghrelin levels were elevated in IPAH. Increased ghrelin levels correlated positively with N-BNP, PASP, RVD and NO, and N-BNP levels correlated positively with RVD and ET-1. Pulmonary vascular pathology is a complex imbalance of opposing forces. Ghrelin may not only provide a novel prognostic biomarker for IPAH but also be a potential new therapeutic strategy.

Liver tumor initiating cells (TICs), a small subset cells in tumor bulk, are responsible for liver tumor initiation, metastasis, and relapse. However, the regulatory mechanism of liver TICs remains largely unknown. Here we found a long noncoding RNA lncAPC, locating near from APC locus, was highly expressed in liver cancer and liver TICs. LncAPC was required for liver TIC self-renewal. Silencing and overexpressing lncAPC showed impaired and enhanced sphere formation capacity of liver TICs, respectively. By recruiting EZH2 to APC promoter, LncAPC inhibits APC transcription and thus drives the activation of Wnt/β-catenin signaling. Attenuate binding between EZH2 and APC promoter was observed upon lncAPC knockdown. What is more, lncAPC-EZH2-APC axis can be targeted to eliminate liver TICs. Altogether, LncAPC promotes liver TIC self-renewal through EZH2-dependent APC transcriptional inhibition.