Highly Upregulated In Liver Cancer Research Articles

A DNA-peptide probe coupled mass spectrometry-based method for the detection of LncRNA in hepatocyte and serum samples

Liver cancer, a prominent contributor to cancer-related deaths, necessitates timely identification for successful intervention. In recent years, long non-coding RNAs (lncRNAs) have gained attention as potential biomarkers for liver cancer, and accurate quantification of lncRNA is essential for early diagnosis of liver cancer. However, existing methods for lncRNA detection rely on amplification and labeling techniques, resulting in semi-quantitative or qualitative outcomes. DNA-peptide technology offers a promising alternative. It has successfully translated nucleic acid quantification into peptide quantification, particularly in the context of miRNA analysis. However, the intricate structure of long-chain lncRNAs presents a challenge not encountered with miRNAs, making the design and acquisition of specific DNA-peptide probes for direct quantification more difficult. In this study, a strategy for lncRNA quantification was developed using a DNA-peptide probe coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based quasi-targeted proteomics. The inherent structural complexity of long-chain lncRNAs was overcome by designing DNA-peptide probes based on their unique sequence segments, enabling direct quantification without the need for amplification. Highly upregulated in liver cancer (HULC) was identified as a target lncRNA through bioinformatics analysis using GEO2R online software. Subsequently, the target lncRNA (i.e., HULC), which had been biotinylated and bound to streptavidin agarose beforehand, was hybridized with the probe. Following trypsin digestion, the reporter peptide was released and quantified using LC-MS/MS. Finally, this method was applied to analyze HULC levels in liver cancer cell lines and serum samples, enabling quantitative assessment and early diagnosis. The results demonstrated that liver cancer diagnostics could be enhanced through the integration of mass spectrometry and DNA-peptide probe technology for lncRNA quantification.

LncRNA HULC augments high glucose-associated pancreatic cancer progression and drug resistance by enhancing YAP activity and autophagy.

One of the confounding factors in pancreatic cancer (PC) pathogenesis is hyperglycemia. The molecular mechanism by which high glucose (HG) influences PC severity is poorly understood. Our investigation delved into the impact of lncRNA highly upregulated in liver cancer (HULC) and its interaction with yes-associated protein (YAP) in regulating the fate of pancreatic ductal adenocarcinoma cells (PDAC) under HG-induced conditions. PDAC cells were cultured under normal or HG conditions. We thereafter measured the effect of HG on the viability of PDAC cells, their migration potential and drug resistance properties. The lncRNAs putatively dysregulated in PC and diabetes were shortlisted by bioinformatics analysis followed by wet lab validation of function. HG led to enhanced proliferation and drug refractoriness in PDAC cells. HULC was identified as one of the major deregulated lncRNAs following bioinformatics analysis. HULC was found to regulate the expression of the potent transcriptional regulator - YAP through selective histone modifications at the YAP promoter. siRNA-mediated ablation of HULC resulted in a concurrent decrease in YAP transcriptional activity. Importantly, HULC and YAP were found to co-operatively regulate the cellular homeostatic process autophagy, thus inculcating drug resistance and proliferative potential in PDAC cells. Moreover, inhibition of autophagy or YAP led to a decrease in HULC levels, suggesting the existence of an inter-regulatory feedback loop. We observed that HG triggers aggressive properties in PDAC cells. Mechanistically, up-regulation of lncRNA HULC resulted in activation of YAP and differential regulation of autophagy coupled to increased proliferation of PDAC cells. Inhibition of HULC and YAP may represent a novel therapeutic strategy for PDAC. Furthermore, this study portrays the intricate molecular interplay between HULC, YAP and autophagy in PDAC pathogenesis.

Qntrolling the LncRNA HULC-Tregs-PD-1 axis inhibits immune escape in the tumor microenvironment

BackgroundImmune escape remains a major challenge in the treatment of malignant tumors. Here, we studied the mechanisms underlying immune escape in the tumor microenvironment and identified a potential therapeutic target. MethodsPathological specimens from patients with liver cancer, soft tissue sarcoma, and liver metastasis of colon cancer were subjected to immunohistochemistry analysis to detect the expression of programmed death-1 (PD-1) in the tumor microenvironment (TME). Additionally, the expression of regulatory T cells (Tregs) and long non-coding RNAs (lncRNAs), such as highly upregulated in liver cancer (HULC) was evaluated by fluorescence in situ hybridization, and the relationship between HULC, Treg cells, and PD-1 was determined. The animals were divided into H22 hepatic carcinoma and S180 sarcoma groups. Each group was divided into Foxp3−/-C57BL/6J and C57BL/6J mice. Thereafter, mice were inoculated with 0.1 ml S180 sarcoma cells or 0.1 ml H22 hepatoma cells, at a concentration of 1 × 107/ml. The number of splenic CD4+CD25+Foxp3+ T cells was detected by flow cytometry, and serum interleukin-10 (IL-10) and transforming growth factor β1 (TGF-β1) levels were detected using a Luminex liquid suspension chip. Expression of PD-1, fork head box P3 (Foxp3), and HULC in the TME, were analyzed and the therapeutic effect of inhibiting the lncRNA HULC-Treg-PD-1 axis in malignant tumors was determined. ResultsHigh expression of lncRNA HULC promotes the proliferation of Treg cells and increases PD-1 expression in the tumor microenvironment. The HULC-Treg-PD-1 axis plays an immunosuppressive role and promotes the proliferation of malignant tumors. Knocking out the Foxp3 gene can affect the HULC-Treg-PD-1 axis and reduce PD-1, IL-10, and TGF-β1 expression to control the growth of malignant tumors. ConclusionThe lncRNA HULC-Treg-PD-1 axis promotes the growth of malignant tumors. This axis could be modulated to reduce PD-1, IL-10, and TGF-β1 expression and the subsequent immune escape. The inhibition of immune escape in the tumor microenvironment can be achieved by controlling the LncRNA HULC-Treg-PD-1 axis.

Combinatorial Gene Expression Profiling of Serum HULC, HOTAIR, and UCA1 lncRNAs to Differentiate Hepatocellular Carcinoma from Liver Diseases: A Systematic Review and Meta-Analysis.

Hepatocellular carcinoma (HCC) presents a significant global health challenge due to limited early detection methods, primarily relying on conventional approaches like imaging and alpha-fetoprotein (AFP). Although non-coding RNAs (ncRNAs) show promise as potential biomarkers in HCC, their true utility remains uncertain. We conducted a comprehensive review of 76 articles, analyzing 88 circulating lncRNAs in 6426 HCC patients. However, the lack of a standardized workflow protocol has hampered holistic comparisons across the literature. Consequently, we herein confined our meta-analysis to only a subset of these lncRNAs. The combined analysis of serum highly upregulated in liver cancer (HULC) gene expression with homeobox transcript antisense intergenic RNA (HOTAIR) and urothelial carcinoma-associated 1 (UCA1) demonstrated markedly enhanced sensitivity and specificity in diagnostic capability compared to traditional biomarkers or other ncRNAs. These findings could have substantial implications for the early diagnosis and tailored treatment of HCC.

Roles of long noncoding RNA in triple-negative breast cancer.

Long noncoding RNAs (lncRNAs) play crucial roles in regulating various hallmarks in cancers. Triple-negative (Estrogen receptor, ER; Human epidermal growth factor receptor 2, HER2; Progesterone receptor, PR) breast cancer (TNBC) is the most aggressive form of breast cancers with a poor prognosis and no available molecular targeted therapy. We reviewed the current literature on the roles of lncRNAs in the pathogenesis, therapy resistance, and prognosis of patients with TBNC. LncRNAs are associated with TNBC pathogenesis, therapy resistance, and prognosis. For example, lncRNAs such as small nucleolar RNA host gene 12 (SNHG12), highly upregulated in liver cancer (HULC) HOX transcript antisense intergenic RNA (HOTAIR), lincRNA-regulator of reprogramming (LincRNA-ROR), etc., are aberrantly expressed in TNBC and are involved in the pathogenesis of the disease. LncRNAs act as a decoy, scaffold, or sponge to regulate the expression of genes, miRNAs, and transcription factors associated with pathogenesis and progression of TNBC. Moreover, lncRNAs such as ferritin heavy chain 1 pseudogene 3 (FTH1P3), BMP/OP-responsive gene (BORG) contributes to the therapy resistance property of TNBC through activating ABCB1 (ATP-binding cassette subfamily B member 1) drug efflux pumps by increasing DNA repair capacity or by inducing signaling pathway involved in therapeutic resistance. In this review, we outline the functions of various lncRNAs along with their molecular mechanisms involved in the pathogenesis, therapeutic resistance of TBNC. Also, the prognostic implications of lncRNAs in patients with TNBC is illustrated. Moreover, potential strategies targeting lncRNAs against highly aggressive TNBC is discussed in this review.

Down-regulation of long noncoding RNA HULC inhibits the inflammatory response in ankylosing spondylitis by reducing miR-556-5p-mediated YAP1 expression

ObjectiveAnkylosing spondylitis (AS) is a progressive systemic disease characterized by a chronic inflammatory response in the sacroiliac joints and spine. Long noncoding RNAs suggest significant actions in the progression of AS. Therefore, a specific lncRNA, highly upregulated in liver cancer (HULC), was studied here regarding its functions and related mechanisms in AS.MethodsMeasurements of miR-556-5p, HULC, and YAP1 expression were performed on AS cartilage tissues and chondrocytes. The interaction between miR-556-5p and HULC or YAP1 was verified. CCK-8, flow cytometry and enzyme-linked immunosorbent assay were used to evaluate the effects of HULC, miR-556-5p, and YAP1 on the proliferation, apoptosis, and inflammatory response of AS chondrocytes. Furthermore, the action of HULC/miR-556-5p/YAP1 was experimentally observed in AS mice.ResultsHULC and YAP1 levels were augmented, while miR-556-5p levels were suppressed in AS cartilage tissues and chondrocytes. Downregulating HULC or upregulating miR-556-5p stimulated chondrocyte proliferation and inhibited apoptosis and inflammation in AS. miR-556-5p was a downstream factor of HULC, and YAP1 was a potential target of miR-556-5p. The improvement effect of downregulated HULC on AS chondrocytes was saved when YAP1 expression was forced. In addition, silence of HULC improved the pathological injury of spinal cartilage in AS mice by enhancing miR-556-5p-related regulation of YAP1.ConclusionHULC inhibition relieves the inflammatory response in AS by reducing miR-556-5p-mediated YAP1 expression.

Long noncoding RNA HULC regulates the NF-κB pathway and represents a promising prognostic biomarker in liver cancer.

Long noncoding RNAs (lncRNAs) are involved in a diverse array of biological processes. While lncRNAs are commonly upregulated in hepatocellular carcinoma (HCC), the specific regulatory roles they play in this oncogenic context require further study and clarification. Although HULC (lncRNA highly upregulated in liver cancer) is involved in disease pathogenesis, its precise role in this context remains unclear. Here, we have explored the mechanistic relevance of HULC expression by assessing its expression in patient samples. The importance of this lncRNA in the onset and progression of HCC was investigated through in vitro approaches including Western blotting, quantitative PCR, Transwell assays, electron microscopy, wound healing assays, and real-time cell analysis (RTCA). Additionally, the in vivo functions of this lncRNA were assessed using an orthotopic HCC xenograft in nude mouse model system. HULC was identified as a lncRNA that is highly upregulated in human liver tumors. In vitro, HULC was able to promote HCC malignancy, although its excess overexpression also led robust autophagic induction, promoting the increased expression of autophagy-associated genes including LC3 and Beclin-1. At a mechanistic level, HULC was able to promote the phosphorylation of p65 and IkBkB thus enhancing autophagy by increasing LC3II levels in a manner dependent upon the NF-κB pathway. HULC downregulation was also linked to impaired orthotopic HCC tumor growth in vivo. The link between HULC and autophagy may play a role in disease progression. These results suggest that HULC is an oncogenic lncRNA, and may thus offer value as a prognostic biomarker and promoter of HCC development, in addition to being a potential therapeutic target in this cancer type.

HULC targets the IGF1R–PI3K-AKT axis in trans to promote breast cancer metastasis and cisplatin resistance

Insulin-like growth factor I receptor (IGF1R) is frequently upregulated in breast cancer. Due to its intrinsic tyrosine kinase activity, aberrant activation of the IGF1R signaling axis may enhance tumor cell proliferation and cancer stemness, causing tumor relapse, metastasis and resistance to chemotherapy. We utilized a chromatin RNA in situ reverse transcription (CRIST) approach to characterize molecular factors that regulate the IGF1R network. We identified lncRNA HULC (Highly Upregulated in Liver Cancer) as a key trans-regulator of IGF1R in breast cancer cells. Loss of HULC suppressed the expression of IGF1R and the activation of its downstream PI3K/AKT pathway, while HULC overexpression activated the axis in breast cancer cells. Using a transcription-associated trap (RAT) assay, we demonstrated that HULC functioned as a nuclear lncRNA and epigenetically activated IGF1R by directly binding to the intragenic regulatory elements of the gene, orchestrating intrachromosomal interactions, and promoting histone H3K9 acetylation. The activated HULC-IGF1R/PI3K/AKT pathway mediated tumor resistance to cisplatin through the increased expression of cancer stemness markers, including NANOG, SOX2, OCT4, CD44 and ALDH1A1. In immunodeficient mice, stimulation of the HULC-IGF1R pathway promoted tumor metastasis. These data suggest that HULC may be a new epigenetic target for IGF1R axis-targeted therapeutic intervention.

Induction of cancer cell stemness in glioma through glycolysis and the long noncoding RNA HULC-activated FOXM1/AGR2/HIF-1α axis

Gliomas are the most common primary intracranial tumor, accounting for more than 70% of brain malignancies. Studies indicate that highly upregulated in liver cancer (HULC), a long noncoding RNA (lncRNA), functions as an oncogene in gliomas. However, the underlying mechanism of HULC in gliomas remains under-studied and was subsequently investigated in the current study. Brain tissues were clinically collected from 50 patients with glioblastoma (GBM) and 35 patients with acute craniocerebral injury, followed by immunohistochemical detection of the expression patterns of Forkhead box M1 (FOXM1), anterior gradient 2 (AGR2), and hypoxia-inducible factor-1α (HIF-1α). After flow cytometry-based sorting of the CD133+ glioma stem cells (GSCs) from the U251 cell line, the obtained cells were subjected to lentivirus infection. Afterwards, the proliferation, stemness, and apoptosis of GSCs were evaluated using sphere formation, immunofluorescence, and flow cytometry assays, respectively. In addition, the interactions among HULC, FOXM1, AGR2, and HIF-1α were identified using RNA immunoprecipitation (RIP), RNA pull-down, Chromatin immunoprecipitation (ChIP), IP, and dual luciferase reporter assays. Last, the specific effects were validated in vivo. HULC was upregulated in GBM tissues and GSCs, which may promote the progression of glioma. On the other hand, silencing of HULC reduced the stemness, inhibited the proliferation, and promoted the apoptosis and differentiation of GSCs. In addition, HULC further stabilized FOXM1 expression in GSCs through ubiquitination, while FOXM1 activated AGR2 transcription to promote HIF-1α expression. Moreover, HULC promoted the glycolysis and stemness of GSCs through its regulation of the FOXM1/AGR2/HIF-1α axis, consequently exacerbating the occurrence and development of glioma. The findings obtained in our study indicate that HULC stabilizes the FOXM1 protein by ubiquitination to upregulate the expression of AGR2 and HIF-1α, which further promote the glycolysis of and maintain the stemness of GSCs, to enhance the tumorigenicity of GSCs, highlighting a novel therapeutic target for glioma.

Long non-coding RNA HULC stimulates the epithelial-mesenchymal transition process and vasculogenic mimicry in human glioblastoma.

BackgroundLong non‐coding RNA (lncRNA) HULC (highly upregulated in liver cancer) is considered as an oncogenic factor for various malignant tumors. This study aimed to reveal the role of lncRNA HULC in the malignant behavior of glioblastoma (GBM) by exploring its effects on the epithelial–mesenchymal transition (EMT) and vasculogenic mimicry (VM) of human GBM.Materials and MethodsThe contents of VM in 27 GBM samples were assessed by immunohistochemistry‐histology and their association with progress‐free survival (PFS) was analyzed. Human GBM SHG44 and U87 cells were manipulated to establish stable lncRNA HULC overexpressing and silencing cells by lentivirus‐based technology. The effects of altered lncRNA HULC on vasculogenic tubular formation, invasion, and EMT process in GBM cells were tested in vitro and the growth of implanted GBM tumors and their EMT process were examined in vivo.ResultsThe numbers of VM were positively associated with disease progression, but negatively with PFS periods of GBM patients. Compared with the control vec cells, lncRNA HULC overexpression significantly increased the tubular formation, invasion, and EMT process of both SHG44 and U87 cells, accompanied by promoting the growth of implanted GBM tumors and EMT process in mice. LncRNA HULC silencing had opposite effects on the tubular formation, invasion, and EMT process as well as tumor growth of GBM cells.ConclusionLncRNA HULC stimulates the EMT process and VM in human GBM, and may be a therapeutic target for intervention of GBM.

Long noncoding RNA HULC contributes to paclitaxel resistance in ovarian cancer via miR-137/ITGB8 axis.

Long noncoding RNA (lncRNA) highly upregulated in liver cancer (HULC) has been reported to be implicated in chemoresistance. However, the potential mechanism of HULC in paclitaxel (PTX)-resistant ovarian cancer (OC) remains undefined. The expression of RNAs and proteins was measured by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot assay. The PTX resistance and apoptotic rate were assessed via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. Furthermore, the interaction between miR-137 and HULC or integrin beta-8 (ITGB8) was predicted by miRcode and starBase v2.0 and then verified by dual luciferase reporter and RNA pull-down assays. In addition, the xenograft mice model was established to explore the effects of HULC in vivo. HULC was significantly upregulated and miR-137 was downregulated in PTX-resistant OC tissues and cells. Also, the HULC depletion suppressed tumor growth and PTX resistance in PTX-treated mice. miR-137 was verified as a target of HULC and directly targeted ITGB8. And HULC knockdown downregulated ITGB8 expression by targeting miR-137. miR-137 inhibitor or ITGB8 overexpression mitigated the suppressive impacts of HULC knockdown on PTX resistance. Collectively, HULC modulated ITGB8 expression to promote PTX resistance of OC by sponging miR-137.

Antifouling lipid membrane coupled with silver nanoparticles for electrochemical detection of nucleic acids in biological fluids

Electrochemical method capable of detecting specific nucleic acids in complex fluid will undoubtedly advance the diagnosis of many kinds of diseases. Herein, by coupling lipid membrane with silver nanoparticles (AgNPs), we develop a new electrochemical method for sensitive and reliable detection of nucleic acids in biological fluids. The advantages of lipid membrane especially its excellent antifouling ability is employed to enhance the applicability of the method in complex environment; while the significant solid-state Ag/AgCl response of AgNPs is used to ensure the detection sensitivity of the method. The core of this method's workflow is the target-induced Y-shape structure formation, which results in the recruitment of AgNPs to the electrode surface, producing considerable electrochemical responses used for target nucleic acid detection. Taking highly upregulated in liver cancer (HULC), a liver cancer-related long non-coding RNA as a model target, the method exhibits high sensitivity, specificity, and reproducibility with a detection limit of 0.42 fM. Moreover, the method displays desirable usability in biological fluids such as serum, which will be of great potential in clinical diagnosis.

LncRNA highly upregulated in liver cancer regulates imatinib resistance in chronic myeloid leukemia via the miR-150-5p/MCL1 axis.

Chronic myeloid leukemia (CML) is a type of myeloproliferative neoplasm. Aberrant expression of long noncoding RNA highly upregulated in liver cancer (HULC) has been implicated in tumor progression, including CML. This study aimed to investigate the role of HULC in CML. The levels of HULC, miR-150-5p and myeloid cell leukemia 1 (MCL1) were examined by quantitative real-time PCR or western blot assay. Cell counting kit-8 assay was used to detect cell viability and half inhibition concentration. Cell apoptosis was monitored by flow cytometry and western blot. The interaction among HULC, miR-150-5p and MCL1 was validated by dual-luciferase reporter assay. The expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT) and phosphorylation-AKT was evaluated using western blot assay. HULC and MCL1 were upregulated, whereas miR-150-5p was downregulated in bone marrow mononuclear cells of CML patients and CML cells. HULC overexpression increased imatinib resistance in K562 cells, and HULC depletion enhanced imatinib sensitivity in imatinib-resistant cells (K562-R). Mechanically, HULC was a sponge of miR-150-5p. HULC contributed to imatinib resistance through regulation of miR-150-5p. MCL1 bound to miR-150-5p and reversed the effect of HULC on imatinib resistance. HULC regulated the PI3K/AKT pathway via the miR-150-5p/MCL1 axis. These findings indicated that HULC enhanced imatinib resistance in CML by modulating the miR-150-5p/MCL1 axis, providing a promising biomarker for CML.

Long non‐coding RNA HULC protects against atherosclerosis via inhibition of PI3K/AKT signaling pathway

AbstractStudies on the roles of long non‐coding RNA in atherosclerosis (AS) have been extensively explored. However, the action of lncRNA highly upregulated in liver cancer (HULC) in AS still needs in‐depth investigations. Hence, this study is launched towards the translation of HULC‐oriented mechanism in AS. Mouse AS models were established by high cholesterol and high fat feeding. AS mice were injected with restored HULC or phosphatidylinositide 3‐kinase/protein kinase B (PI3K/AKT) signaling pathway inhibitor to explore their roles in AS. Blood lipid, inflammation and oxidative stress were detected as well as HULC, PI3K, phosphated‐PI3K (p‐PI3K), AKT, p‐AKT, and aortic vascular cell apoptosis were determined. HULC was poorly expressed, p‐PI3K and p‐AKT were highly expressed in AS. HULC inhibited the PI3K/AKT signaling pathway. In AS, by inhibition of PI3K/AKT signaling pathway, restored HULC restrained atherosclerotic plaque formation, alleviated aortic intimal damage and reduced collagen fiber content in aorta, down‐regulated blood lipid levels, and inhibited inflammation, oxidative stress and aortic vascular cell apoptosis. Our study elucidates that HULC alleviates AS via inhibition of the PI3K/AKT signaling pathway, which provides a potential biomarker for treatment of AS.

Potential role of lncRNA HULC/miR‑128‑3p/RAC1axis in the inflammatory response during LPS‑induced sepsis in HMEC‑1 cells.

Sepsis is a serious clinical condition characterized by systemic inflammation. The long noncoding RNA (lncRNA) highly upregulated in liver cancer (HULC) was validated to partake in the development of sepsis. The present study aimed to investigate the potential mechanism of HULC in lipopolysaccharide (LPS)-induced sepsis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis was employed to examine the expression of HULC, microRNA (miR)-128-3p, Rac family small GTPase 1 (RAC1) and pro-inflammatory factors [IL-6, TNF-α, intercellular adhesion molecule (ICAM1) and vascular cell adhesion molecule (VCAM1)] in the serum of patients with sepsis or LPS-induced human dermal microvascular endothelial cells (HMEC-1). Flow cytometry and western blot assays were performed to detect cell apoptosis. The targeted relationship among HULC, miR-128-3p and RAC1 was confirmed by a dual-luciferase reporter assay, RNA binding protein immunoprecipitation (RIP) assay and RNA pull-down assay. HULC and RAC1 were found to be upregulated, and miR-128-3p was downregulated in the serum of patients with sepsis and LPS-stimulated HMEC-1 cells. LPS promoted apoptosis and inflammation, which were decreased by silencing of HULC. HULC targeted miR-128-3p and negatively regulated its expression. HULC knockdown protected HMEC-1 cells from LPS-induced injury by upregulating miR-128-3p. RAC1 was a target of miR-128-3p, and gain of RAC1 also relieved the silencing of HULC-mediated suppressive effects on apoptosis and inflammation in LPS-stimulated HMEC-1 cells. In conclusion, HULC knockdown partially reversed LPS-induced sepsis via the regulation of miR-128-3p/RAC1 axis.

LncRNA HULC shRNA disinhibits miR-377-5p to suppress the growth and invasion of hepatocellular carcinoma in vitro and hepatocarcinogenesis in vivo

BackgroundAberrant expression of up-regulated long non-coding RNA [LncRNA highly upregulated in liver cancer (HULC)] has been observed to play an important regulatory role in the development of multiple human diseases. However, the molecular mechanism underlying the role of HULC and miR-377-5p in HCC needs to be urgently explored.MethodsThe mRNA and protein expression levels of HULC were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot in hepatocellular carcinoma (HCC) cell line HB611, HepG2 and H22, respectively. HULC-shRNA was transfected into HepG-2 cells, which were randomly divided into the control, shRNA-NC, and sh-HULC groups. The correlation between HULC and miR-377-5p was analyzed by performing a luciferase reporter assay. The targeting relationship between miR-377-5p and hypoxia-inhibitory factor-1α (HIF-1α) was also investigated using a luciferase reporter assay. Sh-HULC and miR-377-5p inhibitors were transfected either alone or together into HepG2 cells, and which were divided into the control group, the sh-HULC group, the miR-377-5p inhibitor, and the sh-HULC + inhibitor group for subsequent experiments. HepG2 cell proliferation and invasion were measured by 5-Ethynyl-2-Deoxyuridine (EdU) staining and Transwell invasion assay, respectively. Western plot was carried out to detect the protein expression levels of Ki67, PCNA, E-cadherin, and N-cadherin. Tumor xenograft mouse models were established to confirm the effect of HULC down-regulation on the development of HCC in vivo.ResultsThe mRNA and protein expression levels of HULC were markedly increased, whereas the mRNA expression levels of miR-377-5p were decreased in HCC cell lines. HepG2 cell proliferation and invasion were suppressed in the Sh-HULC group, while miR-377-5p showed the opposite. Further experiments exhibited that miR-377-5p was targeted by HULC, and an negative correlation between HULC and miR-377-5p was observed. Importantly, the in vivo experiments indicated that down-regulation of HULC could inhibit tumor growth. Taken together, our research demonstrated that down-regulation of HULC plays an anti-cancer role through restrainingHepG2 cell proliferation and invasion.ConclusionsIn summary, our in vitro and in vivo findings confirmed HULC to play a role in the progression of HCC, with the underlying mechanism possibly involving the miR-377-5p/HIF-1α pathway.

Interference of miR-107 with Atg12 is inhibited by HULC to promote metastasis of hepatocellular carcinoma.

Highly upregulated in liver cancer (HULC) had a significant predictive effect on tumor growth and metastasis of hepatocellular carcinoma (HCC); however, the mechanisms of HULC on HCC still need to be clarified. We attempted to determine the roles of HULC and miR‐107 in autophagy and invasion of HCC. HULC siRNA reduced the level of autophagy. The impact of HULC siRNA on invasion can be reversed by activating autophagy in HCC cell lines. Further studies on HULC and autophagy were conducted. An interacting sequence between HULC and miR‐107, as well as miR‐107 and Atg12, was predicted by software. The relationship of each pair of molecules was confirmed by luciferase reporter assays. The negative impacts of miR‐107 on autophagy and invasion were proved in HCC cell lines. The inhibitor of miR‐107‐promoted invasion can also be reversed by Atg12 siRNA. The changes of miR‐107, Atg12, epithelial‐mesenchymal transition, and autophagy in transplanted tumors of mouse models also confirmed the results in HCC cell lines. Finally, we find that HULC acts as an endogenous sponge, which abolishes the binding of miR‐107 on the Atg12 3′‐UTR and promotes autophagy and metastasis of HCC.

Liver X receptor inhibits the growth of hepatocellular carcinoma cells via regulating HULC/miR-134-5p/FOXM1 axis

Hepatocellular carcinoma (HCC) is one of the most common malignancies with a high rate of mortality. Highly upregulated in liver cancer (HULC), the specifically overexpressed long non-coding RNA in human HCC, plays important roles in promoting the growth and metastasis of HCC cells. So downregulating HULC will be benefit to HCC treatment. The nuclear receptor LXR (liver X receptor), consist of α and β isoforms, exerts significant anti-HCC effects, but the corresponding mechanisms are not well known, especially, it's unclear whether LXR is involved in the regulation of HULC. In this study, we found that LXR inhibited HCC cell growth by downregulating HULC, and LXRα (but not LXRβ) caused HULC downregulation. Luciferase reporter assays showed that LXR suppressed transcriptional activity of HULC gene promoter, and chromatin immunoprecipitation assays revealed that LXRα (but not LXRβ) bound to HULC promoter region. Furthermore, LXR increased miR-134-5p while decreased FOXM1 by reducing HULC. Additionally, HULC upregulated FOXM1 via sequestrating miR-134-5p, and miR-134-5p downregulated FOXM1 by targeting 3′-UTR of its mRNA. The in vivo experiments showed that LXR repressed the growth of HCC xenografts, and decreased HULC and FOXM1 while increased miR-134-5p in the xenografts. In summary, these findings for the first time demonstrate that LXR inhibits HCC cell growth by modulating HULC/miR-134-5p/FOXM1 axis, suggesting that the pathway LXR/HULC/miR-134-5p/FOXM1 may serve as a novel target for HCC treatment.

Overexpression of lncRNA HULC Attenuates Myocardial Ischemia/reperfusion Injury in Rat Models and Apoptosis of Hypoxia/reoxygenation Cardiomyocytes via Targeting miR-377-5p through NLRP3/Caspase‑1/IL‑1β Signaling Pathway Inhibition

ABSTRACT Objective Acute myocardial infarction (AMI) is characterized by myocardial tissue necrosis and activation of inflammatory response. This study aims to elucidate the potential mechanism underlying the protective effects of long non-coding RNA (lncRNA) highly up-regulated in liver cancer (HULC) against myocardial ischemia/reperfusion (I/R) injury in rat models and apoptosis of cardiomyocytes. Methods We firstly established rat models of myocardial I/R injury and rat cardiomyocyte (H9c2 cells) models of hypoxia/reoxygenation (H/R) injury. Sprague-Dawley (SD) neonatal rats were randomized into four groups: sham, I/R, I/R+ microRNA (miR) −377-5p mimic, and I/R+ miR-377-5p antagomir, respectively. Then, histopathological examination was applied. Apoptosis was evaluated by transferase-mediated dUTP nick end labeling (TUNEL) staining. Cell vitality was measured using MTT assay. The concentrations of creatine kinase MB (CK-MB), cardiac troponin I (cTnI), interleukin (IL) −6 (IL-6), and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). The expression of Cleaved-Caspase-3, Caspase-3, NOD-like receptor P3 (NLRP3), Caspase-1, and IL-1β was analyzed by immunohistochemical (IHC) or Western blot analysis. Results We found that HULC was downregulated and miR-377-5p was upregulated in IR-injured myocardial tissue and the H/R-induced H9c2 cell. Overexpression of miR-377-5p increased myocardial dysfunction and apoptosis and activated formation and secretion of IL-6 and TNF-α. The preprocessing of miR-377-5p silencing emerged opposite results. Strikingly, dual luciferase reporter assay showed that HULC was a sponge of miR-377-5p. Subsequently, mechanism experiments revealed that NLRP3/Caspase‑1/IL‑1β was a target axis of miR-377-5p. In vitro, the protective effect of HULC overexpression on H9c2 cell viability and inflammation was offset by miR-377-5p silencing. Finally, rescue assay suggested that HULC-miR-377-5p -NLRP3/Caspase‑1/IL‑1β axis regulated the apoptosis and inflammation of H/R-induced H9c2 cells. Conclusions Overall, these results indicate that the protective effect of HULC against myocardial I/R injury and H/R cardiomyocyte apoptosis partially relies on the inhibition of NLRP3/Caspase‑1/IL‑1β signaling pathway.

Interactome analysis reveals that lncRNA HULC promotes aerobic glycolysis through LDHA and PKM2

Interacting with proteins is a crucial way for long noncoding RNAs (lncRNAs) to exert their biological responses. Here we report a high throughput strategy to characterize lncRNA interacting proteins in vivo by combining tobramycin affinity purification and mass spectrometric analysis (TOBAP-MS). Using this method, we identify 140 candidate binding proteins for lncRNA highly upregulated in liver cancer (HULC). Intriguingly, HULC directly binds to two glycolytic enzymes, lactate dehydrogenase A (LDHA) and pyruvate kinase M2 (PKM2). Mechanistic study suggests that HULC functions as an adaptor molecule that enhances the binding of LDHA and PKM2 to fibroblast growth factor receptor type 1 (FGFR1), leading to elevated phosphorylation of these two enzymes and consequently promoting glycolysis. This study provides a convenient method to study lncRNA interactome in vivo and reveals a unique mechanism by which HULC promotes Warburg effect by orchestrating the enzymatic activities of glycolytic enzymes.