Causal effect between gut microbiota and metabolic syndrome in European population: a bidirectional mendelian randomization study.

BACKGROUND: Observational studies have reported that gut microbiota composition is associated with metabolic syndrome. However, the causal effect of gut microbiota on metabolic syndrome has yet to be confirmed. METHODS: We performed a bidirectional Mendelian randomization study to investigate the causal effect between gut microbiota and metabolic syndrome in European population. Summary statistics of gut microbiota were from the largest available genome-wide association study meta-analysis (n = 13,266) conducted by the MiBioGen consortium. The summary statistics of outcome were obtained from the most comprehensive genome-wide association studies of metabolic syndrome (n = 291,107). The inverse-variance weighted method was applied as the primary method, and the robustness of the results was assessed by a series of sensitivity analyses. RESULTS: In the primary causal estimates, Actinobacteria (OR = 0.935, 95% CI = 0.878-0.996, P = 0.037), Bifidobacteriales (OR = 0.928, 95% CI = 0.868-0.992, P = 0.028), Bifidobacteriaceae (OR = 0.928, 95% CI = 0.868-0.992, P = 0.028), Desulfovibrio (OR = 0.920, 95% CI = 0.869-0.975, P = 0.005), and RuminococcaceaeUCG010 (OR = 0.882, 95% CI = 0.803-0.969, P = 0.009) may be associated with a lower risk of metabolic syndrome, while Lachnospiraceae (OR = 1.130, 95% CI = 1.016-1.257, P = 0.025), Veillonellaceae (OR = 1.055, 95% CI = 1.004-1.108, P = 0.034) and Olsenella (OR = 1.046, 95% CI = 1.009-1.085, P = 0.015) may be linked to a higher risk for metabolic syndrome. Reverse MR analysis demonstrated that abundance of RuminococcaceaeUCG010 (OR = 0.938, 95% CI = 0.886-0.994, P = 0.030) may be downregulated by metabolic syndrome. Sensitivity analyses indicated no heterogeneity or horizontal pleiotropy. CONCLUSIONS: Our Mendelian randomization study provided causal relationship between specific gut microbiota and metabolic syndrome, which might provide new insights into the potential pathogenic mechanisms of gut microbiota in metabolic syndrome and the assignment of effective therapeutic strategies.

Erratum: Linc-KILH potentiates Notch1 signaling through inhibiting KRT19 phosphorylation and promotes the malignancy of hepatocellular carcinoma: Erratum.

[This corrects the article DOI: 10.7150/ijbs.52279.].

Protein disulfide isomerase family member 4 promotes triple-negative breast cancer tumorigenesis and radiotherapy resistance through JNK pathway.

BACKGROUND: Despite radiotherapy ability to significantly improve treatment outcomes and survival in triple-negative breast cancer (TNBC) patients, acquired resistance to radiotherapy poses a serious clinical challenge. Protein disulfide isomerase exists in endoplasmic reticulum and plays an important role in promoting protein folding and post-translational modification. However, little is known about the role of protein disulfide isomerase family member 4 (PDIA4) in TNBC, especially in the context of radiotherapy resistance. METHODS: We detected the presence of PDIA4 in TNBC tissues and paracancerous tissues, then examined the proliferation and apoptosis of TNBC cells with/without radiotherapy. As part of the validation process, xenograft tumor mouse model was used. Mass spectrometry and western blot analysis were used to identify PDIA4-mediated molecular signaling pathway. RESULTS: Based on paired clinical specimens of TNBC patients, we found that PDIA4 expression was significantly higher in tumor tissues compared to adjacent normal tissues. In vitro, PDIA4 knockdown not only increased apoptosis of tumor cells with/without radiotherapy, but also decreased the ability of proliferation. In contrast, overexpression of PDIA4 induced the opposite effects on apoptosis and proliferation. According to Co-IP/MS results, PDIA4 prevented Tax1 binding protein 1 (TAX1BP1) degradation by binding to TAX1BP1, which inhibited c-Jun N-terminal kinase (JNK) activation. Moreover, PDIA4 knockdown suppressed tumor growth xenograft model in vivo, which was accompanied by an increase in apoptosis and promoted tumor growth inhibition after radiotherapy. CONCLUSIONS: The results of this study indicate that PDIA4 is an oncoprotein that promotes TNBC progression, and targeted therapy may represent a new and effective anti-tumor strategy, especially for patients with radiotherapy resistance.

GAS1 Promotes Ferroptosis of Liver Cells in Acetaminophen-Induced Acute Liver Failure.

Purpose: Acute liver failure (ALF) is a clinically fatal disease that leads to the rapid loss of normal liver function. Acetaminophen (APAP) is a leading cause of drug-induced ALF. Ferroptosis, defined as iron-dependent cell death associated with lipid peroxide accumulation, has been shown to be strongly associated with APAP-induced liver injury. Growth arrest-specific 1 (GAS1) is a growth arrest-specific gene, which is closely related to the inhibition of cell growth and promotion of apoptosis. However, the functional role and underlying mechanism of GAS1 in APAP-induced ferroptosis remain unknown. Methods: We established liver-specific overexpression of GAS1 (GAS1AAV8-OE) mice and the control (GAS1AAV8-vector) mice by tail vein injection of male mice with adeno-associated virus. APAP at 500 mg/kg was intraperitoneally injected into these two groups of mice to induce acute liver failure. The shRNA packaged by the lentivirus inhibits GAS1 gene expression in human hepatoma cell line HepaRG (HepaRG-shNC and HepaRG-shGAS1-2) and primary hepatocytes of mice with liver-specific overexpression of GAS1 were isolated and induced by APAP in vitro to further investigate the regulatory role of GAS1 in APAP-induced acute liver failure. Results: APAP-induced upregulation of ferroptosis, levels of lipid peroxides and reactive oxygen species, and depletion of glutathione were effectively alleviated by the ferroptosis inhibitor, ferrostatin-1, and downregulation of GAS1 expression. GAS1 overexpression promoted ferroptosis-induced lipid peroxide accumulation via p53, inhibiting its downstream target, solute carrier family 7 member 11. Conclusion: Collectively, our findings suggest that GAS1 overexpression plays a key role in aggravating APAP-induced acute liver injury by promoting ferroptosis-induced accumulation of lipid peroxides.

Long noncoding RNA MyD88 functions as a promising diagnostic biomarker in hepatocellular carcinoma.

Background: Hepatocellular carcinoma (HCC) is one of the most frequent malignancies. Alpha-fetoprotein (AFP) has some limitations in diagnosing early HCC. Recently, long noncoding RNAs (lncRNAs) showed great potential as tumor diagnostic biomarkers, and lnc-MyD88 was previously identified as a carcinogen in HCC. Here, we explored its diagnostic value as a plasma biomarker. Materials and methods: Quantitative real-time PCR was adopted to detect lnc-MyD88 expression in plasma samples of 98 HCC patients, 52 liver cirrhosis (LC) patients, and 105 healthy people. The correlation between lnc-MyD88 and clinicopathological factors was analyzed through chi-square test. The receiver operating characteristic (ROC) curve was used to analyze the sensitivity, specificity, Youden index, and area under the curve (AUC) of lnc-MyD88 and AFP alone and in combination for the diagnosis of HCC. The relationship between MyD88 and immune infiltration was analyzed by single sample gene set enrichment analysis (ssGSEA) algorithm. Results: Lnc-MyD88 was highly expressed in plasma samples of HCC and hepatitis B virus (HBV)-associated HCC patients. Lnc-MyD88 had better diagnostic value than AFP in HCC patients using healthy people or LC patients as control (healthy people, AUC: 0.776 vs. 0.725; LC patients, AUC: 0.753 vs. 0.727). The multivariate analysis showed that lnc-MyD88 had great diagnostic value for distinguishing HCC from LC and healthy people. Lnc-MyD88 had no correlation with AFP. Lnc-MyD88 and AFP were independent diagnostic factors for HBV-associated HCC. The AUC, sensitivity, and Youden index of the combined diagnosis of lnc-MyD88 and AFP combined were higher than those of lnc-MyD88 and AFP alone. The ROC curve of lnc-MyD88 for the diagnosis of AFP-negative HCC was plotted with a sensitivity of 80.95%, a specificity of 79.59%, and an AUC value of 0.812 using healthy people as control. The ROC curve also presented its great diagnostic value using LC patients as control (sensitivity: 76.19%, specificity: 69.05%, AUC value: 0.769). Lnc-MyD88 expression was correlated with microvascular invasion in HBV-associated HCC patients. MyD88 was positively correlated with infiltrating immune cells and immune-related genes. Conclusion: The high expression of plasma lnc-MyD88 in HCC is distinct and could be utilized as a promising diagnostic biomarker. Lnc-MyD88 had great diagnostic value for HBV-associated HCC and AFP-negative HCC, and it had higher efficacy in combination with AFP.

Classification of Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma Based on Radiomic Analysis.

INTRODUCTION: Considering the narrow window of surgery, early diagnosis of liver cancer is still a fundamental issue to explore. Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICCA) are considered as two different types of liver cancer because of their distinct pathogenesis, pathological features, prognosis, and responses to adjuvant therapies. Qualitative analysis of image is not enough to make a discrimination of liver cancer, especially early-stage HCC or ICCA. METHODS: This retrospective study developed a radiomic-based model in a training cohort of 122 patients. Radiomic features were extracted from computed tomography (CT) scans. Feature selection was operated with the least absolute shrinkage and operator (LASSO) logistic method. The support vector machine (SVM) was selected to build a model. An internal validation was conducted in 89 patients. RESULTS: In the training set, the AUC of the evaluation of the radiomics was 0.855 higher than for radiologists at 0.689. In the valuation cohorts, the AUC of the evaluation was 0.847 and the validation was 0.659, which indicated that the established model has a significantly better performance in distinguishing the HCC from ICCA. CONCLUSION: We developed a radiomic diagnosis model based on CT image that can quickly distinguish HCC from ICCA, which may facilitate the differential diagnosis of HCC and ICCA in the future.

The cancer-testis lncRNA lnc-CTHCC promotes hepatocellular carcinogenesis by binding hnRNP K and activating YAP1 transcription.

Cancer-testis (CT) genes participate in the initiation and progression of cancer, but the role of CT-associated long non-coding RNAs (CT-lncRNAs) in hepatocellular carcinoma (HCC) is still elusive. Here, we discovered a conserved CT-lncRNA, named lnc-CTHCC, which was highly expressed in the testes and HCC. A lnc-CTHCC-knockout (KO) mouse model further confirmed that the global loss of lnc-CTHCC inhibited the occurrence and development of HCC. In vitro and in vivo assays also showed that lnc-CTHCC promoted HCC growth and metastasis. Mechanistically, lnc-CTHCC bound to heterogeneous nuclear ribonucleoprotein K (hnRNP K), which was recruited to the YAP1 promoter for its activation. Additionally, the N6-methyladenosine (m6A) modification was mediated by N6-adenosine-methyltransferase 70-kDa subunit (METTL3) and recognized by insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1)/IGF2BP3, which maintained lnc-CTHCC stability and increased its expression in HCC. Together, our results show that lnc-CTHCC directly binds to hnRNP K and promotes hepatocellular carcinogenesis and progression by activating YAP1 transcription, suggesting that lnc-CTHCC is a potential biomarker and therapeutic target of HCC.

ASRGL1 Correlates With Immune Cell Infiltration in Hepatocellular Carcinoma and Can Serve as a Prognostic Biomarker.

BACKGROUND: The enzyme L-asparaginase (ASRGL1) catalyzes the hydrolysis of L-asparagine (Asn) to L-aspartic acid (Asp) and ammonia. Numerous studies have shown a strong correlation between ASRGL1 expression and tumorigenesis. However, the expression and biological function of ASRGL1 in hepatocellular carcinoma (HCC) are still unclear. METHODS: We explored the mRNA expression of ASRGL1 in HCC using the HCCDB, Oncomine, and TIMER 2.0 databases. Western blotting and immunohistochemical analyses were also used to determine the mRNA expression of ASRGL1 in HCC. LinkedOmics was used to analyze the genes co-expressed with ASRGL1 and regulators including kinases, miRNAs, and transcription factors. The Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the co-expressed genes were also investigated using LinkedOmics. The correlation between ASRGL1 expression and immune infiltrates was analyzed using the TIMER 2.0 and Gene Expression Profiling Interactive Analysis (GEPIA) databases. The effects of ASRGL1 expression on patient outcome were investigated using the UALCAN and GEPIA databases, and the Kaplan-Meier plotter. c-Bioportal was used to explore the mutations of ASRGL1 in HCC. RESULTS: Compared with the adjacent tissues, ASRGL1 was upregulated in HCC. High ASRGL1 expression in HCC indicated poor relapse-free survival, progression-free survival, disease-specific survival, and overall survival. The expression of ASRGL1 was significantly correlated with infiltrating levels of B cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells in HCC. CONCLUSION: Our findings suggest that ASRGL1 is overexpressed in HCC and that ASRGL1 expression was significantly correlated with immune infiltration in HCC and prognosis. Therefore, ASRGL1 may serve as a biomarker for the early diagnosis and treatment of HCC.

Linc-KILH potentiates Notch1 signaling through inhibiting KRT19 phosphorylation and promotes the malignancy of hepatocellular carcinoma.

Long noncoding RNAs (LncRNAs) are emerging as crucial regulators in the pathophysiological process of various tumors, including HCC. Here, we identify a novel lncRNA Linc-KILH (KRT19 interacting long noncoding RNA in hepatocellular carcinoma), which is significantly up-regulated in HCC tissues and positively correlated with larger tumor size, severer microvascular invasion, more intrahepatic metastasis and decreased survival of HCC patients. Silence of Linc-KILH remarkably inhibited the proliferation and metastasis abilities of KRT19-positive HCC cells in vitro and in vivo. Mechanistically, Linc-KILH interacts with KRT19 and then inhibits the phosphorylation of KRT19 on Ser35, thereby, enhancing the translocation of KRT19 from cytoplasm to membrane in KRT19 positive HCC cells. Additionally, we validated that KRT19 interacts with ß-catenin but not RAC1 in HCC cells. Linc-KILH enhanced the interaction between ß-catenin and KRT19 in cytoplasm and promoted the nuclear translocation of ß-catenin in HCC cells. Furthermore, Linc-KILH could enhance the promoting function of KRT19 on Notch1 signaling with the existence of KRT19 in HCC cells. Collectively, we revealed that Linc-KILH exerts a vital function in KRT19 positive HCC progression and may likely be developed into an effective therapeutic target for HCC.

LncRNA loc339803 acts as CeRNA of miR-30a-5p to promote the migration and invasion of hepatocellular carcinoma cells.

Background: Hepatocellular carcinoma (HCC), a most common malignant tumor, has an unfavorable clinical outcome. Emerging evidence has demonstrated that long noncoding RNAs (lncRNAs) play an important role in the carcinogenesis and progression of HCC. However, the clinical significances and the biological roles of most lncRNAs in HCC remain poorly understood. Methods: The expression levels of lncRNA loc339803 in HCC tissues and cell lines were determined by quantitative real-time polymerase chain reaction (qRT-PCR) assay. The cellular sublocalization of loc339803 was determined by fluorescence in situ hybridization and nuclear and cytoplasmic RNA isolation assay. Western blot, CCK-8, Edu, colony formation, migration and invasion assays were used to investigate the roles of loc339803 in HCC progression in vitro. A mouse model for lung metastasis was constructed to evaluate the role of loc339803 in HCC development in vivo. The correlations among loc339803, miR-30a-5p and SNAIL1 were validated by qRT-PCR and a dual- luciferase reporter assay. Results: The expression of loc339803 was upregulated in HCC tissues and cell lines, and positively correlated with tumor size, advanced tumor stage, higher serum AFP level and poor prognosis of HCC patients. Loc339803 can promote the migration and invasion of HCC cells in vivo and in vitro. Further studies demonstrated that loc339803 functioned as a competing endogenous RNA (ceRNA) by directly binding to miR-30a-5p, thus up-regulating the expression of SNAIL1, a target gene of miR-30a-5p. Moreover, miR-30a-5p upregulation blocked the enhanced migration and invasion of HCC cells induced by loc339803 overexpression. Conclusions: Loc339803 may be oncogenic in HCC and associated with poor clinical outcomes. LncRNA loc339803 might promote the invasion and migration of HCC cells through regulating miR-30a-5p/ SNAIL1 axis.

Circ_0075829 facilitates the progression of pancreatic carcinoma by sponging miR-1287-5p and activating LAMTOR3 signalling.

Pancreatic cancer (PC) is a leading cause of cancer-related mortality globally. Though increasing evidence has demonstrated that circular RNAs (circRNAs) are linked to the development and progression of cancers, the biological functions of circRNAs in PC remain largely unexplored so far. Based on previous studies, Hsc_circ_0075829 (circ_0075829) was screened out and then further identified in PC clinical specimens and cell lines by real-time PCR. After the stability tests, a series of in vitro and in vivo functional experiments were performed to investigate the role of circ_0075829 in PC development. Furthermore, fluorescent in situ hybridization (FISH), bioinformatics tools, dual-luciferase assays and rescue experiments were conducted to clarify the regulatory mechanisms of circ_0075829 in SW1990 and BxPC-3 cells. Compared with paracancerous tissues, the expression of circ_0075829 was increased in PC tissues, which was positively correlated with the clinical features of PC. Knockdown of circ_0075829 significantly suppressed the proliferative, migratory and invasive rates of SW1990 and BxPC-3 cells both in vitro and in vivo. Bioinformatics analysis and dual-luciferase reporter gene assay indicated that circ_0075829 could bind to miR-1287-5p. Mechanism research and rescue experiments demonstrated that circ_0075829 could regulate the LAMTOR3/p-ERK signalling pathway via sponging miR-1287-5p in PC cell lines. Our data reveal that the circ_0075829 could facilitate the proliferation and metastasis of PC through circ_0075829/miR-1287-5p/LAMTOR3 axis.

lncRNA PCBP1-AS1 Aggravates the Progression of Hepatocellular Carcinoma via Regulating PCBP1/PRL-3/AKT Pathway.

BACKGROUND: Hepatocellular carcinoma (HCC) is a very belligerent primary liver tumor with high metastatic potential. Aberrant expression of lncRNAs drives tumorous invasion and metastasis. Whether lncRNAs engage mechanisms of liver cancer metastasis remains largely unexplored. PATIENTS AND METHODS: We collected HCC tissues from the tumors and their adjacent normal samples in the Chinese population and analyzed the levels of lncRNAs by microarray analysis. The gain- and loss-of-function analysis demonstrated that PCBP1-AS1 accelerated tumorous growth and metastasis in vivo and in vitro. Moreover, we used RNA-pulldown assay to show that PCBP1-AS1 physically interacted with polyC-RNA-binding protein 1 (PCBP1); meanwhile, PCBP1-AS1 was indeed detected in RIP with the PCBP1 antibody. Mechanistically, we first explored the relationship between PCBP1-AS1 and PCBP1 in HCC cell lines. RESULTS: Here we show that PCBP1-AS1, identified by microarray analysis on pre- and post-operative HCC plasma specimens, was highly expressed in human HCC, clinically verified as a prometastatic factor and markedly associated with poor prognosis in patients with hepatocellular carcinoma. PCBP1-AS1 was negatively related with PCBP1 at the messenger RNA and protein expression levels. PCBP1-AS1 triggered PRL-3 and AKT in HCC tumor cells. Additionally, the double knockout of PCBP1 and PCBP1-AS1 abolished the PCBP1-AS1-induced PRL-3-AKT signalling pathway activation. CONCLUSION: The upregulation of PCBP1-AS1 enhances proliferation and metastasis in HCC, thus regulating the PCBP1-PRL-3-AKT signalling pathway.

The Down-Regulation of SUZ12 Accelerates the Migration and Invasion of Liver Cancer Cells via Activating ERK1/2 Pathway.

The suppressor of zest 12 (SUZ12), an essential subunit of the transcription polycomb repressive complex 2 (PRC2), has been found to be involved in HBV X-induced oncogenic transformation in hepatocellular carcinoma (HCC). However, the specific function of SUZ12 has not yet been determined in the pathogenesis of migration and invasion of HBV-associated HCC. Here, our results showed that SUZ12 was significantly down-regulated in HBV-related HCC tissues compared with adjacent non-tumor tissues by immunohistochemical and Western blot assays. The 5-years survival rate was worse in patients with low expression level of SUZ12. SUZ12 silencing increased the migration and invasion of HCC cells, and its overexpression impaired HCC cells migration and invasion. Knockdown of SUZ12 activated ERK1/2 pathway and increased MMP9 (matrix metallopeptidase 9) and MMP2 (matrix metallopeptidase 2) expression, whereas SUZ12 overexpression had opposite effects. Specific ERK1/2 inhibitor (SCH772984) significantly decreased HCC cells migration and invasion caused by SUZ12 shRNA. Thus, the liver cancer-down-regulated SUZ12 accelerated the invasion and metastasis of HCC cells. These effects might be associated with deregulation of SUZ12 activating ERK1/2, MMP2 and MMP9 in HCC cells.

LncRNA-uc002mbe.2 Interacting with hnRNPA2B1 Mediates AKT Deactivation and p21 Up-Regulation Induced by Trichostatin in Liver Cancer Cells.

Long non-coding RNAs (lncRNAs) have been implicated in liver carcinogenesis. We previously showed that the induction of lncRNA-uc002mbe.2 is positively associated with the apoptotic effect of trichostatin A (TSA) in hepatocellular carcinoma (HCC) cells. The current study further analyzed the role of uc002mbe.2 in TSA-induced liver cancer cell death. The level of uc002mbe.2 was markedly increased by TSA in the cytoplasm of HCC cells. Knockdown of uc002mbe.2 prohibited TSA-induced G2/M cell cycle arrest, p21 induction, and apoptosis of Huh7 cells and reversed the TSA-mediated decrease in p-AKT. RNA pull-down and RNA-binding protein immunoprecipitation (RIP) assays revealed that TSA induced an interaction between uc002mbe.2 and heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) in Huh7 cells. This interaction mediated AKT deactivation and p21 induction in liver cancer cells. In an athymic xenograft mouse model, knockdown of uc002mbe.2 significantly prohibited the TSA-mediated reduction in tumor size and weight. In addition, the ability of TSA to reduce hnRNPA2B1 and p-AKT levels and induce p21 in the xenograft tumors was prevented by uc002mbe.2 knockdown. Therefore, the interaction of uc002mbe.2 and hnRNPA2B1 in mediating AKT deactivation and p21 induction is involved in the cytostatic effect of trichostatin in liver cancer cells.