The ligation between ERMAP, galectin-9 and dectin-2 promotes Kupffer cell phagocytosis and antitumor immunity.

Kupffer cells, the liver tissue resident macrophages, are critical in the detection and clearance of cancer cells. However, the molecular mechanisms underlying their detection and phagocytosis of cancer cells are still unclear. Using in vivo genome-wide CRISPR-Cas9 knockout screening, we found that the cell-surface transmembrane protein ERMAP expressed on various cancer cells signaled to activate phagocytosis in Kupffer cells and to control of liver metastasis. ERMAP interacted with ß-galactoside binding lectin galectin-9 expressed on the surface of Kupffer cells in a manner dependent on glycosylation. Galectin-9 formed a bridging complex with ERMAP and the transmembrane receptor dectin-2, expressed on Kupffer cells, to induce the detection and phagocytosis of cancer cells by Kupffer cells. Patients with low expression of ERMAP on tumors had more liver metastases. Thus, our study identified the ERMAP-galectin-9-dectin-2 axis as an 'eat me' signal for Kupffer cells.

SPHK1/S1P/S1PR pathway promotes the progression of peritoneal fibrosis by mesothelial-mesenchymal transition.

Long-term exposure to non-physiologically compatible dialysate inevitably leads to peritoneal fibrosis (PF) in patients undergoing peritoneal dialysis (PD), and there is no effective prevention or treatment for PF. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid produced after catalysis by sphingosine kinase (SPHK) 1/2 and activates signals through the S1P receptor (S1PR) via autocrine or paracrine. However, the role of SPHK1/S1P/S1PR signaling has never been elucidated in PF. In our research, we investigated S1P levels in peritoneal effluents and demonstrated the role of SPHK1/S1P/S1PR pathway in peritoneal fibrosis. It was found that S1P levels in peritoneal effluents were positively correlated with D/P Cr (r = 0.724, p < .001) and negatively correlated with 4 h ultrafiltration volume (r = -0.457, p < .001). S1PR1 and S1PR3 on peritoneal cells were increased after high glucose exposure in vivo and in vitro. Fingolimod was applied to suppress S1P/S1PR pathway. Fingolimod restored mouse peritoneal function by reducing interstitial hyperplasia, maintaining ultrafiltration volume, reducing peritoneal transport solute rate, and mitigating the protein expression changes of fibronectin, vimentin, α-SMA, and E-cadherin induced by PD and S1P. Fingolimod preserved the morphology of the human peritoneal mesothelial cells, MeT-5A, and moderated the mesothelial-mesenchymal transition (MMT) process. We further delineated that SPHK1 was elevated in peritoneal cells after high glucose exposure and suppression of SPHK1 in MeT-5A cells reduced S1P release. Overexpression of SPHK1 in MeT-5A cells increased S1P levels in the supernatant and fostered the MMT process. PF-543 treatment, targeting SPHK1, alleviated deterioration of mouse peritoneal function. In conclusion, S1P levels in peritoneal effluent were correlated with the deterioration of peritoneal function. SPHK1/S1P/S1PR pathway played an important role in PF.

Heterozygous Spink1 c.194+2T>C mutation promotes chronic pancreatitis after acute attack in mice.

BACKGROUND & AIMS: Mutations in genes, including serine protease inhibitor Kazal-type 1 (SPINK1), influence disease progression following sentinel acute pancreatitis event (SAPE) attacks. SPINK1 c.194+2T > C intron mutation is one of the main mutants of SPINK1，which leads to the impairment of SPINK1 function by causing skipping of exon 3. Research on the pathogenesis of SAPE attacks would contribute to the understanding of the outcomes of acute pancreatitis. Therefore, the aim of the study was to clarify the role of SPINK1 c.194+2T > C mutation in the CP progression after an AP attack. METHODS: SAPE attacks were induced in wildtype and SPINK mutant (Spink1 c.194+2T > C) mice by cerulein injection. The mice were sacrificed at 24 h, 14 d, 28 d, and 42 d post-SAPE. Data-independent acquisition (DIA) proteomic analysis was performed for the identification of differentially expressed protein in the pancreatic tissues. Functional analyses were performed using THP-1 and HPSCs. RESULTS: Following SAPE attack, the Spink1 c.194+2T > C mutant mice exhibited a more severe acute pancreatitis phenotype within 24 h. In the chronic phase, the chronic pancreatitis phenotype was more severe in the Spink1 c.194+2T > C mutant mice after SAPE. Proteomic analysis revealed elevated IL-33 level in Spink1 c.194+2T > C mutant mice. Further in vitro analyses revealed that IL-33 induced M2 polarization of macrophages and activation of pancreatic stellate cells. CONCLUSION: Spink1 c.194+2T > C mutation plays an important role in the prognosis of patients following SAPE. Heterozygous Spink1 c.194+2T > C mutation promotes the development of chronic pancreatitis after an acute attack in mice through elevated IL-33 level and the induction of M2 polarization in coordination with pancreatic stellate cell activation.

Identification of novel factors that affect the onset of idiopathic chronic pancreatitis: The role for microRNA-323b-5p.

BACKGROUND: The c.194+2 T>C variant of serine protease inhibitor Kazal type 1 (SPINK1) is a known genetic risk factor found in Chinese patients with idiopathic chronic pancreatitis (ICP), but the early-onset mechanisms of ICP are still unclear. METHODS: Complementary experimental approaches were used to pursue other potential pathologies in the present study. The serum level of SPINK1 of ICP patients in the Han population in China was detected and verified by an enzyme-linked immunosorbent assay. Next, differentially expressed proteins and microRNAs from plasma samples of early-onset and late-onset ICP patients were screened by proteomic analysis and microarray, respectively. RESULTS: Combined with these advanced methods, the data strongly suggest that the regulatory effects of microRNAs were involved in the early-onset mechanism of the ICP by in vitro experiments. There was no significant difference in the plasma SPINK1 expression between the early-onset ICP and the late-onset patients. However, the expression of plasma glutathione peroxidase (GPx3) in early-onset ICP patients was markedly lower than that in late-onset ICP patients, although the level of hsa-miR-323b-5p was lower in late-onset patients compared to the early-onset ICP group. In vitro experiments confirmed that hsa-miR-323b-5p could increase apoptosis in caerulein-treated pancreatic acinar cells and inhibit the expression of GPx3. CONCLUSIONS: The up-regulated hsa-miR-323b-5p might play a crucial role in the early-onset mechanisms of ICP by diminishing the antioxidant activity through the down-regulation of GPx3.

Tamoxifen exerts anti-peritoneal fibrosis effects by inhibiting H19-activated VEGFA transcription.

BACKGROUND: Peritoneal dialysis (PD) remains limited due to dialysis failure caused by peritoneal fibrosis. Tamoxifen (TAM), an inhibitor of estrogen receptor 1 (ESR1), has been reported to treat fibrosis, but the underlying mechanism remains unknown. In this study, we sought to explore whether tamoxifen played an anti-fibrotic role by affecting transcription factor ESR1. METHODS: ESR1 expression was detected in the human peritoneum. Mice were daily intraperitoneally injected with 4.25% glucose PD dialysate containing 40 mM methylglyoxal for 2 weeks to establish PD-induced peritoneal fibrosis. Tamoxifen was administrated by daily gavage, at the dose of 10 mg/kg. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assay were performed to validate ESR1 bound H19 promoter. Gain-of-function and loss-of-function experiments were performed to investigate the biological roles of H19 on the mesothelial-mesenchymal transition (MMT) of human peritoneal mesothelial cells (HPMCs). Intraperitoneal injection of nanomaterial-wrapped 2'-O-Me-modified small interfering RNA was applied to suppress H19 in the mouse peritoneum. RNA immunoprecipitation and RNA pull-down assays demonstrated binding between H19 and p300. Exfoliated peritoneal cells were obtained from peritoneal dialysis effluent to analyze the correlations between ESR1 (or H19) and peritoneal solute transfer rate (PSTR). RESULTS: ESR1 was increased significantly in the peritoneum after long-term exposure to PD dialysate. Tamoxifen treatment ameliorated high glucose-induced MMT of HPMCs, improved ultrafiltration rate, and decreased PSTR of mouse peritoneum. Tamoxifen reduced the H19 level by decreasing the ESR1 transcription of H19. Depletion of H19 reversed the pro-fibrotic effect of high glucose while ectopic expression of H19 exacerbated fibrotic pathological changes. Intraperitoneal injection of nanomaterial-wrapped 2'-O-Me-modified siRNAs targeting H19 mitigated PD-related fibrosis in mice. RNA immunoprecipitation (RIP) and RNA pull-down results delineated that H19 activated VEGFA expression by binding p300 to the VEGFA promoter and inducing histone acetylation of the VEGFA promoter. ESR1 and H19 were promising targets to predict peritoneal function. CONCLUSIONS: High glucose-induced MMT of peritoneal mesothelial cells in peritoneal dialysis via activating ESR1. In peritoneal mesothelial cells, ESR1 transcribed the H19 and H19 binds to transcription cofactor p300 to activate the VEGFA. Targeting ESR1/H19/VEGFA pathway provided new hope for patients undergoing peritoneal dialysis.

METTL16 promotes hepatocellular carcinoma progression through downregulating RAB11B-AS1 in an m6A-dependent manner.

BACKGROUND: The molecular mechanisms driving hepatocellular carcinoma (HCC) remain largely unclear. As one of the major epitranscriptomic modifications, N6-methyladenosine (m6A) plays key roles in HCC. The aim of this study was to investigate the expression, roles, and mechanisms of action of the RNA methyltransferase methyltransferase-like protein 16 (METTL16) in HCC. METHODS: The expression of METTL16 and RAB11B-AS1 was determined by RT-qPCR. The regulation of RAB11B-AS1 by METTL16 was investigated by RNA immunoprecipitation (RIP), methylated RIP (MeRIP), and RNA stability assays. In vitro and in vivo gain- and loss-of-function assays were performed to investigate the roles of METTL16 and RAB11B-AS1. RESULTS: METTL16 was upregulated in HCC, and its increased expression was correlated with poor prognosis of HCC patients. METTL16 promoted HCC cellular proliferation, migration, and invasion, repressed HCC cellular apoptosis, and promoted HCC tumoral growth in vivo. METTL16 directly bound long noncoding RNA (lncRNA) RAB11B-AS1, induced m6A modification of RAB11B-AS1, and decreased the stability of RAB11B-AS1 transcript, leading to the downregulation of RAB11B-AS1. Conversely to METTL16, RAB11B-AS1 is downregulated in HCC, and its decreased expression was correlated with poor prognosis of patients with HCC. Furthermore, the expression of RAB11B-AS1 was negatively correlated with METTL16 in HCC tissues. RAB11B-AS1 repressed HCC cellular proliferation, migration, and invasion, promoted HCC cellular apoptosis, and inhibited HCC tumoral growth in vivo. Functional rescue assays revealed that overexpression of RAB11B-AS1 reversed the oncogenic roles of METTL16 in HCC. CONCLUSIONS: This study identified the METTL16/RAB11B-AS1 regulatory axis in HCC, which represented novel targets for HCC prognosis and treatment.

SLC38A4 functions as a tumour suppressor in hepatocellular carcinoma through modulating Wnt/ß-catenin/MYC/HMGCS2 axis.

BACKGROUND: Many molecular alterations are shared by embryonic liver development and hepatocellular carcinoma (HCC). Identifying the common molecular events would provide a novel prognostic biomarker and therapeutic target for HCC. METHODS: Expression levels and clinical relevancies of SLC38A4 and HMGCS2 were investigated by qRT-PCR, western blot, TCGA and GEO datasets. The biological roles of SLC38A4 were investigated by functional assays. The downstream signalling pathway of SLC38A4 was investigated by qRT-PCR, western blot, immunofluorescence, luciferase reporter assay, TCGA and GEO datasets. RESULTS: SLC38A4 silencing was identified as an oncofetal molecular event. DNA hypermethylation contributed to the downregulations of Slc38a4/SLC38A4 in the foetal liver and HCC. Low expression of SLC38A4 was associated with poor prognosis of HCC patients. Functional assays demonstrated that SLC38A4 depletion promoted HCC cellular proliferation, stemness and migration, and inhibited HCC cellular apoptosis in vitro, and further repressed HCC tumorigenesis in vivo. HMGCS2 was identified as a critical downstream target of SLC38A4. SLC38A4 increased HMGCS2 expression via upregulating AXIN1 and repressing Wnt/ß-catenin/MYC axis. Functional rescue assays showed that HMGCS2 overexpression reversed the oncogenic roles of SLC38A4 depletion in HCC. CONCLUSIONS: SLC38A4 downregulation was identified as a novel oncofetal event, and SLC38A4 was identified as a novel tumour suppressor in HCC.

LncRNA-ATB participates in the regulation of calcium oxalate crystal-induced renal injury by sponging the miR-200 family.

BACKGROUND: LncRNA-ATB is a long noncoding RNA (lncRNA) activated by transforming growth factor ß (TGF-ß) and it has important biological functions in tumours and nontumour diseases. Meanwhile, TGF-ß is the most critical regulatory factor in the process of nephrotic fibrosis and calcium oxalate (CaOx) crystal-induced renal injury. The present study aimed to investigate the biological function and mechanism of lncRNA-ATB in CaOx crystal-induced renal injury. METHODS: The expression level of lncRNA-ATB was detected by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), the expression levels of epithelial-mesenchymal transition (EMT) markers, TGF-ß1 and Kidney Injury Molecule-1 (KIM-1) were detected by qRT-PCR, immunofluorescence staining or western blot analysis, cell proliferation was measured with a CCK-8 kit, cell apoptosis was measured by flow cytometry and TUNEL staining, and cell injury was detected with the Cytotoxicity lactate dehydrogenase (LDH) Assay kit and the expression level of KIM-1. RESULTS: The expression levels of lncRNA-ATB and TGF-ß1 were significantly increased in HK-2 cells after coincubation with calcium oxalate monohydrate (COM). COM stimulation caused significant injury in the HK-2 cells, induced cell apoptosis, inhibited cell proliferation, and induced EMT changes. After COM stimulation, the expression levels of the epithelial cell markers E-cadherin and zonula occludens (ZO)-1 in HK-2 cells significantly decreased, whereas the levels of the mesenchymal cell markers N-cadherin, vimentin and α-smooth muscle actin (α-SMA) significantly increased. Interference with lncRNA-ATB expression significantly relieved the COM-induced cell injury, cell apoptosis, proliferation inhibition, and EMT changes. The expression levels of the microRNA-200 (miR-200) family in the HK-2 cells after coincubation with COM were significantly decreased. MiR-200a mimics relieved the COM-induced cell injury, apoptosis, proliferation inhibition, and EMT changes, whereas miR-200a inhibitors abolished the lncRNA-ATB interference-induced relief of the COM-induced cell injury, apoptosis, proliferation inhibition, and EMT. CONCLUSION: LncRNA-ATB promoted the COM-induced cell injury, cell apoptosis, proliferation inhibition, and EMT to participate in the process of CaOx crystal-induced renal injury by sponging miR-200s.

METTL14 suppresses the metastatic potential of hepatocellular carcinoma by modulating N6 -methyladenosine-dependent primary MicroRNA processing.

N6 -Methyladenosine (m6 A) modification has been implicated in many biological processes. However, its role in cancer has not been well studied. Here, we demonstrate that m6 A modifications are decreased in hepatocellular carcinoma, especially in metastatic hepatocellular carcinoma, and that methyltransferase-like 14 (METTL14) is the main factor involved in aberrant m6 A modification. Moreover, METTL14 down-regulation acts as an adverse prognosis factor for recurrence-free survival of hepatocellular carcinoma and is significantly associated with tumor metastasis in vitro and in vivo. We confirm that METTL14 interacts with the microprocessor protein DGCR8 and positively modulates the primary microRNA 126 process in an m6 A-dependent manner. Further experiments show that microRNA 126 inhibits the repressing effect of METTL14 in tumor metastasis. CONCLUSION: These studies reveal an important role of METTL14 in tumor metastasis and provide a fresh view on m6 A modification in tumor progression. (Hepatology 2017;65:529-543).

Long noncoding RNA MRCCAT1 promotes metastasis of clear cell renal cell carcinoma via inhibiting NPR3 and activating p38-MAPK signaling.

BACKGROUND: Recent evidences showed that long noncoding RNAs (lncRNAs) are frequently dysregulated and play important roles in various cancers. Clear cell renal cell carcinoma (ccRCC) is one of the leading cause of cancer-related death, largely due to the metastasis of ccRCC. However, the clinical significances and roles of lncRNAs in metastatic ccRCC are still unknown. METHODS: lncRNA expression microarray analysis was performed to search the dysregulated lncRNA in metastatic ccRCC. quantitative real-time PCR was performed to measure the expression of lncRNAs in human ccRCC samples. Gain-of-function and loss-of-function experiments were performed to investigate the biological roles of lncRNAs on ccRCC cell proliferation, migration, invasion and in vivo metastasis. RNA pull-down, RNA immunoprecipitation, chromatin immunoprecipitation, and western blot were performed to explore the molecular mechanisms underlying the functions of lncRNAs. RESULTS: The microarray analysis identified a novel lncRNA termed metastatic renal cell carcinoma-associated transcript 1 (MRCCAT1), which is highly expressed in metastatic ccRCC tissues and associated with the metastatic properties of ccRCC. Multivariate Cox regression analysis revealed that MRCCAT1 is an independent prognostic factor for ccRCC patients. Overexpression of MRCCAT1 promotes ccRCC cells proliferation, migration, and invasion. Depletion of MRCCAT1 inhibites ccRCC cells proliferation, migration, and invasion in vitro, and ccRCC metastasis in vivo. Mechanistically, MRCCAT1 represses NPR3 transcription by recruiting PRC2 to NPR3 promoter, and subsequently activates p38-MAPK signaling pathway. CONCLUSIONS: MRCCAT1 is a critical lncRNA that promotes ccRCC metastasis via inhibiting NPR3 and activating p38-MAPK signaling. Our results imply that MRCCAT1 could serve as a prognostic biomarker and therapeutic target for ccRCC.

Systemic genome screening identifies the outcome associated focal loss of long noncoding RNA PRAL in hepatocellular carcinoma.

UNLABELLED: Systemic analyses using large-scale genomic profiles have successfully identified cancer-driving somatic copy number variations (SCNVs) loci. However, functions of vast focal SCNVs in "protein-coding gene desert" regions are largely unknown. The integrative analysis of long noncoding RNA (lncRNA) expression profiles with SCNVs in hepatocellular carcinoma (HCC) led us to identify the recurrent deletion of lncRNA-PRAL (p53 regulation-associated lncRNA) on chromosome 17p13.1, whose genomic alterations were significantly associated with reduced survival of HCC patients. We found that lncRNA-PRAL could inhibit HCC growth and induce apoptosis in vivo and in vitro through p53. Subsequent investigations indicated that the three stem-loop motifs at the 5' end of lncRNA-PRAL facilitated the combination of HSP90 and p53 and thus competitively inhibited MDM2-dependent p53 ubiquitination, resulting in enhanced p53 stability. Additionally, in vivo lncRNA-PRAL delivery efficiently reduced intrinsic tumors, indicating its potential therapeutic application. CONCLUSIONS: lncRNA-PRAL, one of the key cancer-driving SCNVs, is a crucial stimulus for HCC growth and may serve as a potential target for antitumor therapy.

Aldolase B inhibits metastasis through Ten-Eleven Translocation 1 and serves as a prognostic biomarker in hepatocellular carcinoma.

BACKGROUND: Downregulation of Aldolase B (ALDOB) has been reported in hepatocellular carcinoma. However, its clinical significance and its role in pathogenesis of HCC remain largely unknown. METHODS: We analyzed the expression of ALDOB and its clinical features in a large cohort of 313 HCC patients using tissue microarray and immunohistochemistry. Moreover, the function of stably overexpressed ALDOB in HCC cells was explored in vitro and in vivo. Gene expression microarray analysis was performed on ALDOB-overexpressing SMMC7721 cells to elucidate its mechanism of action. RESULTS: ALDOB downregulation in HCC was significantly correlated with aggressive characteristics including absence of encapsulation, increased tumor size (>5 cm) and early recurrence. ALDOB downregulation was indicative of a shorter recurrence-free survival (RFS) and overall survival (OS) for all HCC patients and early-stage HCC patients (BCLC 0-A and TNM I stage patients). Multiple analyses revealed that ALDOB downregulation was an independent risk factor of RFS and OS. Stable expression of ALDOB in HCC cell lines reduced cell migration in vitro and inhibited lung metastasis, intrahepatic metastasis, and reduced circulating tumor cells in vivo. Mechanistically, we found that cells stably expressing ALDOB show elevated Ten-Eleven Translocation 1 (TET1) expression. Moreover, ALDOB expressing cells have higher levels of methylglyoxal than do control cells, which can upregulate TET1 expression. CONCLUSION: The downregulation of ALDOB could indicate a poor prognosis for HCC patients, and therefore, ALDOB might be considered a prognostic biomarker for HCC, especially at the early stage. In addition, ALDOB inhibits the invasive features of cell lines partly through TET1 expression.

Oncofetal long noncoding RNA PVT1 promotes proliferation and stem cell-like property of hepatocellular carcinoma cells by stabilizing NOP2.

UNLABELLED: Many protein-coding oncofetal genes are highly expressed in murine and human fetal liver and silenced in adult liver. The protein products of these hepatic oncofetal genes have been used as clinical markers for the recurrence of hepatocellular carcinoma (HCC) and as therapeutic targets for HCC. Herein we examined the expression profiles of long noncoding RNAs (lncRNAs) found in fetal and adult liver in mice. Many fetal hepatic lncRNAs were identified; one of these, lncRNA-mPvt1, is an oncofetal RNA that was found to promote cell proliferation, cell cycling, and the expression of stem cell-like properties of murine cells. Interestingly, we found that human lncRNA-hPVT1 was up-regulated in HCC tissues and that patients with higher lncRNA-hPVT1 expression had a poor clinical prognosis. The protumorigenic effects of lncRNA-hPVT1 on cell proliferation, cell cycling, and stem cell-like properties of HCC cells were confirmed both in vitro and in vivo by gain-of-function and loss-of-function experiments. Moreover, mRNA expression profile data showed that lncRNA-hPVT1 up-regulated a series of cell cycle genes in SMMC-7721 cells. By RNA pulldown and mass spectrum experiments, we identified NOP2 as an RNA-binding protein that binds to lncRNA-hPVT1. We confirmed that lncRNA-hPVT1 up-regulated NOP2 by enhancing the stability of NOP2 proteins and that lncRNA-hPVT1 function depends on the presence of NOP2. CONCLUSION: Our study demonstrates that the expression of many lncRNAs is up-regulated in early liver development and that the fetal liver can be used to search for new diagnostic markers for HCC. LncRNA-hPVT1 promotes cell proliferation, cell cycling, and the acquisition of stem cell-like properties in HCC cells by stabilizing NOP2 protein. Regulation of the lncRNA-hPVT1/NOP2 pathway may have beneficial effects on the treatment of HCC.

H19 inhibits RNA polymerase II-mediated transcription by disrupting the hnRNP U-actin complex.

BACKGROUND: H19 was one of the earliest identified, and is the most studied, long noncoding RNAs. It is presumed that H19 is essential for regulating development and disease conditions, and it is associated with carcinogenesis for many types. However the biological function and regulatory mechanism of this conserved RNA, particularly with respect to its effect on transcription, remain largely unknown. METHODS: We performed RNA pulldown, RNA immunoprecipitation and deletion mapping to identify the proteins that are associated with H19. In addition, we employed EU (5-ethynyl uridine) incorporation, immunoprecipitation and Western blotting to investigate the functional aspects of H19. RESULTS: Our research further verifies that H19 is bound to hnRNP U, and this interaction is located within the 5' 882 nt region of H19. Moreover, H19 disrupts the interaction between hnRNP U and actin, which inhibits phosphorylation at Ser5 of the RNA polymerase II (Pol II) C-terminal domain (CTD), consequently preventing RNA Pol II-mediated transcription. We also showed that hnRNP U is essential for H19-mediated transcription repression. CONCLUSIONS: In this study, we demonstrate that H19 inhibits RNA Pol II-mediated transcription by disrupting the hnRNP U-actin complex. GENERAL SIGNIFICANCE: These data suggest that H19 regulates general transcription and exerts wide-ranging effects in organisms.

Long noncoding RNAs associated with liver regeneration 1 accelerates hepatocyte proliferation during liver regeneration by activating Wnt/ß-catenin signaling.

UNLABELLED: In recent years, long noncoding RNAs (lncRNAs) have been investigated as a new class of regulators of biological function. A recent study reported that lncRNAs control cell proliferation in hepatocellular carcinoma (HCC). However, the role of lncRNAs in liver regeneration and the overall mechanisms remain largely unknown. To address this issue, we carried out a genome-wide lncRNA microarray analysis during liver regeneration in mice after 2/3 partial hepatectomy (PH) at various timepoints. The results revealed differential expression of a subset of lncRNAs, notably a specific differentially expressed lncRNA associated with Wnt/ß-catenin signaling during liver regeneration (an lncRNA associated with liver regeneration, termed lncRNA-LALR1). The functions of lncRNA-LALR1 were assessed by silencing and overexpressing this lncRNA in vitro and in vivo. We found that lncRNA-LALR1 enhanced hepatocyte proliferation by promoting progression of the cell cycle in vitro. Furthermore, we showed that lncRNA-LALR1 accelerated mouse hepatocyte proliferation and cell cycle progression during liver regeneration in vivo. Mechanistically, we discovered that lncRNA-LALR1 facilitated cyclin D1 expression through activation of Wnt/ß-catenin signaling by way of suppression of Axin1. In addition, lncRNA-LALR1 inhibited the expression of Axin1 mainly by recruiting CTCF to the AXIN1 promoter region. We also identified a human ortholog RNA of lncRNA-LALR1 (lncRNA-hLALR1) and found that it was expressed in human liver tissues. CONCLUSION: lncRNA-LALR1 promotes cell cycle progression and accelerates hepatocyte proliferation during liver regeneration by activating Wnt/ß-catenin signaling. Pharmacological intervention targeting lncRNA-LALR1 may be therapeutically beneficial in liver failure and liver transplantation by inducing liver regeneration.

METTL14 downregulation drives S100A4+ monocyte-derived macrophages via MyD88/NF-κB pathway to promote MAFLD progression.

Without intervention, a considerable proportion of patients with metabolism-associated fatty liver disease (MAFLD) will progress from simple steatosis to metabolism-associated steatohepatitis (MASH), liver fibrosis, and even hepatocellular carcinoma. However, the molecular mechanisms that control progressive MAFLD have yet to be fully determined. Here, we unraveled that the expression of the N6-methyladenosine (m6A) methyltransferase METTL14 is remarkably downregulated in the livers of both patients and several murine models of MAFLD, whereas hepatocyte-specific depletion of this methyltransferase aggravated lipid accumulation, liver injury, and fibrosis. Conversely, hepatic Mettl14 overexpression alleviated the above pathophysiological changes in mice fed on a high-fat diet (HFD). Notably, in vivo and in vitro mechanistic studies indicated that METTL14 downregulation decreased the level of GLS2 by affecting the translation efficiency mediated by YTHDF1 in an m6A-depedent manner, which might help to form an oxidative stress microenvironment and accordingly recruit Cx3cr1+Ccr2+ monocyte-derived macrophages (Mo-macs). In detail, Cx3cr1+Ccr2+ Mo-macs can be categorized into M1-like macrophages and S100A4-positive macrophages and then further activate hepatic stellate cells (HSCs) to promote liver fibrosis. Further experiments revealed that CX3CR1 can activate the transcription of S100A4 via CX3CR1/MyD88/NF-κB signaling pathway in Cx3cr1+Ccr2+ Mo-macs. Restoration of METTL14 or GLS2, or interfering with this signal transduction pathway such as inhibiting MyD88 could ameliorate liver injuries and fibrosis. Taken together, these findings indicate potential therapies for the treatment of MAFLD progression.

Epigenetic activation of the MiR-200 family contributes to H19-mediated metastasis suppression in hepatocellular carcinoma.

Although numerous long non-coding RNAs (lncRNAs) have been identified in mammals, many of their biological roles remain to be characterized. Early reports suggest that H19 contributes to carcinogenesis, including hepatocellular carcinoma (HCC). Examination of the Oncomine resource showed that most HCC cases express H19 at a level that is comparable with the liver, with a tendency toward lower expression. This is consistent with our previous microarray data and indicates a more complicated role of H19 in HCC that needs to be characterized. In this study, the expression level of H19 was assessed in different regions of HCC patients' liver samples. Loss- and gain-of-function studies on this lncRNA in the HCC cell lines, SMMC7721 and HCCLM3, were used to characterize its effects on gene expression and to assess its effect on HCC metastasis both in vitro and in vivo. In this study, we show that H19 was underexpressed in intratumoral HCC tissues (T), as compared with peritumoral tissues (L). Additionally, low T/L ratio of H19 predicted poor prognosis. H19 suppressed HCC progression metastasis and the expression of markers of epithelial-to-mesenchymal transition. Furthermore, H19 associated with the protein complex hnRNP U/PCAF/RNAPol II, activating miR-200 family by increasing histone acetylation. The results demonstrate that H19 can alter the miR-200 pathway, thus contributing to mesenchymal-to-epithelial transition and to the suppression of tumor metastasis. These data provide an explanation for the hitherto puzzling literature on the relationship between H19 and cancer, and could suggest the development of combination therapies that target H19 and the miR-200 family.

The histone deacetylase 4/SP1/microrna-200a regulatory network contributes to aberrant histone acetylation in hepatocellular carcinoma.

UNLABELLED: As an important epigenetic mechanism, histone acetylation modulates the transcription of many genes and plays important roles in hepatocellular carcinoma (HCC). Aberrations in histone acetylation have been observed in HCC, but the factors that contribute to the aberrations have not been fully elucidated. MicroRNAs (miRNAs), which are noncoding RNAs that regulate gene expression, are involved in important epigenetic mechanisms. In this study, we determined that miR-200a and the level of histone H3 acetylation at its promoter were reduced in human HCC tissues in comparison with adjacent noncancerous hepatic tissues. Furthermore, our results suggested that the histone deacetylase 4 (HDAC4) inhibited the expression of miR-200a and its promoter activity and reduced the histone H3 acetylation level at the mir-200a promoter through a Sp1-dependent pathway. Interestingly, we observed that the miR-200a directly targeted the 3'-untranslated region of the HDAC4 messenger RNA and repressed expression of HDAC4. Therefore, miR-200a ultimately induced its own transcription and increased the histone H3 acetylation level at its own promoter. Through targeting HDAC4, miR-200a also induced the up-regulation of total acetyl-histone H3 levels and increased the histone H3 acetylation level at the p21(WAF/Cip1) promoter. Finally, we determined that miR-200a inhibited the proliferation and migration of HCC cells in vivo and in vitro. CONCLUSION: Our findings suggest that the HDAC4/Sp1/miR-200a regulatory network induces the down-regulation of miR-200a and the up-regulation of HDAC4 in HCC. As a result, down-regulation of miR-200a enhances the proliferation and migration of HCC cells and induces aberrant histone acetylation in HCC. These findings highlight a potential therapeutic approach in targeting the HDAC4/Sp1/miR-200a regulatory network for the treatment of HCC.

Long noncoding RNA high expression in hepatocellular carcinoma facilitates tumor growth through enhancer of zeste homolog 2 in humans.

UNLABELLED: In recent years, long noncoding RNAs (lncRNAs) have been shown to have critical regulatory roles in cancer biology. However, the contributions of lncRNAs to hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remain largely unknown. Differentially expressed lncRNAs between HBV-related HCC and paired peritumoral tissues were identified by microarray and validated using quantitative real-time polymerase chain reaction. Liver samples from patients with HBV-related HCC were analyzed for levels of a specific differentially expressed lncRNA High Expression In HCC (termed lncRNA-HEIH); data were compared with survival data using the Kaplan-Meier method and compared between groups by the log-rank test. The effects of lncRNA-HEIH were assessed by silencing and overexpressing the lncRNA in vitro and in vivo. The expression level of lncRNA-HEIH in HBV-related HCC is significantly associated with recurrence and is an independent prognostic factor for survival. We also found that lncRNA-HEIH plays a key role in G(0) /G(1) arrest, and further demonstrated that lncRNA-HEIH was associated with enhancer of zeste homolog 2 (EZH2) and that this association was required for the repression of EZH2 target genes. CONCLUSIONS: Together, these results indicate that lncRNA-HEIH is an oncogenic lncRNA that promotes tumor progression and leads us to propose that lncRNAs may serve as key regulatory hubs in HCC progression.

Antisense lncRNA LDLRAD4-AS1 promotes metastasis by decreasing the expression of LDLRAD4 and predicts a poor prognosis in colorectal cancer.

Long noncoding RNAs (lncRNAs) have been revealed to play critical roles in tumor initiation and progression. The antisense lncRNA LDLRAD4-AS1 is the longest lncRNA of LDLRAD4, and its expression levels, cellular localization, precise function, and mechanism in colorectal cancer (CRC) remain unknown. In this study, we observed that lncRNA LDLRAD4-AS1 was located in the nucleus of CRC cells and that lncRNA LDLRAD4-AS1 was upregulated in most CRC specimens and cell lines. Overexpression of lncRNA LDLRAD4-AS1 was correlated with poor prognosis in CRC patients. LncRNA LDLRAD4-AS1 upregulation enhanced the migration and invasion of CRC cells in vitro and facilitated CRC metastasis in vivo. Mechanistic investigations suggested that lncRNA LDLRAD4-AS1 could decrease the expression of LDLRAD4 by disrupting the stability of LDLRAD4 mRNA, resulting in epithelial-to-mesenchymal transition (EMT) through upregulating Snail, thereby promoting metastasis in CRC. Our results demonstrated a previously unrecognized LDLRAD4-AS1-LDLRAD4-Snail regulatory axis involved in epigenetic and posttranscriptional regulation that contributes to CRC progression and metastasis.