Hypoxia-induced HIF1A activates DUSP18-mediated MAPK14 dephosphorylation to promote hepatocellular carcinoma cell migration and invasion.

BACKGROUND: Hepatocellular Carcinoma (HCC) is recognized as the second leading cause of cancer-associated deaths globally. Hypoxia-inducible factor 1alpha (HIF1A) has been documented to promote HCC cell migration, invasion and cell cycle. Dual specificity phosphatase 18 (DUSP18) has been predicted to be up-regulated in hypoxia and its expression is positively linked to HIF1A expression in HCC cells. However, their function and molecular mechanism have not been investigated in HCC in depth. PURPOSE: This study aimed to uncover the functional roles of HIF1A and DUSP18, as well as relevant mechanisms underlying their regulation in HCC cells. METHODS: RT-qPCR and western blot were performed to examine gene expression. Functional assays were implemented to reveal the regulatory impact of target genes on HCC cells. Mechanism experiments were conducted to analyze gene interaction. RESULTS: DUSP18 was found to have significantly high expression in hypoxia-induced HCC cells. HIF1A promoted HCC cell migration, invasion and cell cycle by transcriptionally activating DUSP18. DUSP18 mediated MAPK14 dephosphorylation to weaken MAPK14 activity, which further inhibited MAPK14-mediated TP53 phosphorylation, consequently promoting multiple biological behaviors of HCC cells. CONCLUSION: Hypoxia-induced HIF1A activates DUSP18 transcription to further promote MAPK14 dephosphorylation, thereby suppressing TP53 phosphorylation and functionally promoting malignant behaviors of HCC cells.

Long non-coding RNA HOMER3-AS1 drives hepatocellular carcinoma progression via modulating the behaviors of both tumor cells and macrophages.

The crosstalk between cancer cells and tumor microenvironment plays critical roles in hepatocellular carcinoma (HCC). The identification of long non-coding RNAs (lncRNAs) mediating the crosstalk might promote the development of new therapeutic strategies against HCC. Here, we identified a lncRNA, HOMER3-AS1, which is over-expressed in HCC and correlated with poor survival of HCC patients. HOMER3-AS1 promoted HCC cellular proliferation, migration, and invasion, and reduced HCC cellular apoptosis. Furthermore, HOMER3-AS1 promoted macrophages recruitment and M2-like polarization. In vivo, HOMER3-AS1 significantly facilitated HCC progression. Mechanism investigations revealed that HOMER3-AS1 activated Wnt/ß-catenin signaling via upregulating HOMER3. Functional rescue experiments revealed that HOMER3/Wnt/ß-catenin axis mediated the roles of HOMER3-AS1 in promoting HCC cellular malignant phenotypes. Furthermore, colony stimulating factor-1 (CSF-1) was also identified as a critical downstream target of HOMER3-AS1. HOMER3-AS1 increased CSF-1 expression and secretion. Blocking CSF-1 reversed the roles of HOMER3-AS1 in inducing macrophages recruitment and M2 polarization. Furthermore, positive correlations between HOMER3-AS1 and HOMER3 expression, HOMER3-AS1 and CSF-1 expression, and HOMER3-AS1 expression and M2-like macrophages infiltration were found in human HCC tissues. In summary, our findings demonstrated that HOMER3-AS1 drives HCC progression via modulating the behaviors of both tumor cells and macrophages, which are dependent on the activation of HOMER3/Wnt/ß-catenin axis and CSF-1, respectively. HOMER3-AS1 might be a promising prognostic and therapeutic target for HCC.

ADORA2A-AS1 Restricts Hepatocellular Carcinoma Progression via Binding HuR and Repressing FSCN1/AKT Axis.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Increasing evidence revealed that long noncoding RNAs (lncRNAs) were frequently involved in various malignancies. Here, we explored the clinical significances, roles, and mechanisms of lncRNA ADORA2A antisense RNA 1 (ADORA2A-AS1) in HCC. METHODS: The clinical significances of ADORA2A-AS1 in HCC were analyzed using RNA sequencing (RNA-seq) data from The Cancer Genome Atlas (TCGA) project. The expressions of ADORA2A-AS1, Fascin Actin-Bundling Protein 1 (FSCN1), Matrix Metallopeptidase 2 (MMP2), and Baculoviral IAP Repeat Containing 7 (BIRC7) in HCC tissues and cells were measured by qRT-PCR. Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), caspase-3 activity assay, transwell migration and invasion assays, and xenograft growth and metastasis experiments were performed to evaluate the roles of ADORA2A-AS1 in HCC. RNA pull-down, RNA immunoprecipitation, qRT-PCR, Western blot, and RNA stability assay were performed to elucidate the mechanisms of ADORA2A-AS1 in HCC. RESULTS: ADORA2A-AS1 was identified as an HCC-related lncRNA, whose low expression was correlated with advanced stage and poor outcome in HCC. Gain- and loss-of functional experiments demonstrated that ADORA2A-AS1 inhibited HCC cell proliferation, induced cell apoptosis, repressed cell migration and invasion, and repressed xenograft growth and metastasis in vivo. Mechanistically, ADORA2A-AS1 competitively bound HuR (Hu Antigen R), repressed the binding of HuR to FSCN1 transcript, decreased FSCN1 transcript stability, and downregulated FSCN1 expression. The expression of FSCN1 was negatively correlated with ADORA2A-AS1 in HCC tissues. Through downregulating FSCN1, ADORA2A-AS1 repressed AKT pathway activation. Functional rescue assays showed that blocking of FSCN1/AKT axis abrogated the roles of ADORA2A-AS1 in HCC. CONCLUSION: Low-expression ADORA2A-AS1 is correlated with poor survival of HCC patients. ADORA2A-AS1 exerts tumor-suppressive roles in HCC via binding HuR and repressing FSCN1/AKT axis.

lncRNA MAGI2-AS3 Exerts Antioncogenic Roles in Hepatocellular Carcinoma via Regulating the miR-519c-3p/TXNIP Axis.

INTRODUCTION: Our work was aimed to explore the mechanisms of MAGI2 antisense RNA 3 (MAGI2-AS3) in regulating hepatocellular carcinoma (HCC) carcinogenesis. METHODS: MAGI2-AS3, microRNA-519c-3p (miR-519c-3p), and thioredoxin interacting protein (TXNIP) levels in HCC were detected by the RT-qPCR method. Cell proliferation and apoptosis rate were measured using Cell Counting Kit-8 assay and flow cytometry assay. Relationship between MAGI2-AS3, TXNIP, and miR-519c-3p were analyzed via luciferase activity assay, RNA pull-down assay, and RNA immunoprecipitation assay. Mouse xenograft models of HCC were conducted to explore the roles of MAGI2-AS3 in vivo. RESULTS: MAGI2-AS3 levels were elevated, and miR-519c-3p decreased in HCC. MAGI2-AS3 overexpression inhibits while its knockdown stimulates HCC cell growth through miR-519c-3p. Moreover, miR-519c-3p overexpression stimulates HCC cell growth. MAGI2-AS3 serves as competing endogenous RNA (ceRNA) of miR-519c-3p to regulate TXNIP in HCC. And, TXNIP upregulation weakened the influence of MAGI2-AS3 knockdown on HCC cell behaviors. Additionally, MAGI2-AS3 overexpression suppressed HCC tumor growth in vivo. CONCLUSION: MAGI2-AS3 inhibits HCC tumorigenesis through miR-519c-3p/TXNIP axis in vitro and in vivo, indicating MAGI2-AS3 plays a crucial role in HCC development.

SNHG17 Serves as an Oncogenic lncRNA by Regulating the miR-361-3p/STC2 Axis in Rectal Cancer.

Long noncoding RNA (lncRNA) have been reported to be crucial regulators for carcinogenesis, including rectal cancer. This work aimed to explore the roles and associated mechanisms of small nucleolar RNA host gene 17 (SNHG17) in rectal cancer. A quantitative real-time polymerase chain reaction was performed to measure the expression level of SNHG17 in rectal cancer tissues and cells. Cell counting kit-8 (CCK-8) assay and flow cytometry assay were conducted to measure the biological roles of SNHG17 in rectal cancer. In addition, luciferase activity reporter assay, RNA immunoprecipitation (RIP) assay, and rescue experiments were conducted to explore the mechanisms of SNHG17 in rectal cancer. The upregulation status of SNHG17 was identified in rectal cancer tissues and cells. Functionally, knockdown the expression of SNHG17 inhibits rectal cancer cell proliferation via stimulating cell apoptosis. In vivo assay showed that the knockdown of SNHG17 inhibits tumor growth. Furthermore, we showed that microRNA-361-3p (miR-361-3p) has decreased expression in tumor tissues and cells, and SNHG17 functions as a sponge for miR-361-3p. The upregulation status of stanniocalcin 2 (STC2) was also found in rectal cancer, and the knockdown of STC2 hinders cancer progression. In conclusion, lncRNA SNHG17 functions as an oncogenic lncRNA in rectal cancer by regulating the miR-361-3p/STC2 axis.

IGF2BP2 Promotes Liver Cancer Growth Through an m6A-FEN1-Dependent Mechanism.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in China. N6-methyladenosine (m6A) plays an important role in posttranscriptional gene regulation. METTL3 and IGF2BP2 are key genes in the m6A signal pathway and have recently been shown to play important roles in cancer development and progression. In our work, higher METTL3 and IGF2BP2 expression were found in HCC tissues and were associated with a poor prognosis. In addition, IGF2BP2 overexpression promoted HCC proliferation in vitro and in vivo. Mechanistically, IGF2BP2 directly recognized and bound to the m6A site on FEN1 mRNA and enhanced FEN1 mRNA stability. Overall, our study revealed that METTL3 and IGF2BP2, acting as an oncogene, maintained FEN1 expression through an m6A-IGF2BP2-dependent mechanism in HCC cells, and indicated a potential biomarker panel for prognostic prediction in liver cancer.

SNHG5 functions as competitive RNA with miR-23c to regulate HMGB2 expression in hepatocellular carcinoma.

Emerging evidence demonstrated long non-coding RNA (lncRNA) small nucleolar RNA host gene 5 (SNHG5) participates in the tumorigenesis. The aim of this work was to characterize the expression and biology roles of SNHG5 in hepatocellular carcinoma (HCC). Expression level of SNHG5 in HCC cells was analyzed with RT-qPCR. Cell proliferation rate, cell cycle distribution, and cell migration ability was analyzed with cell counting kit-8 assay, flow cytometry, and wound-healing assay, respectively. Targets prediction were performed at LncBase V2.0 and TargetScan. SNHG5 was found elevated expression in HCC cell lines. In vitro functional experiments showed knockdown of SNHG5 inhibits cell proliferation and migration, while overexpression of SNHG5 exerted opposite effects. Mechanism studies showed SNHG5 functions as competitive endogenous RNA (ceRNA) for microRNA-23c (miR-23c) to promote high mobility group box 2 (HMGB2) expression. miR-23c was downregulated, while HMGB2 was upregulated in HCC tissues and cells. We revealed SNHG5 could exert an oncogenic role in HCC via regulating miR-23c/HMGB2 axis. Targeting SNHG5 might be a novel therapeutic measure to suppresses HCC progression.