Long non-coding RNA CASC2 suppresses epithelial-mesenchymal transition of hepatocellular carcinoma cells through CASC2/miR-367/FBXW7 axis

TGF-β1-Induced LINC01094 promotes epithelial-mesenchymal transition in hepatocellular carcinoma through the miR-122-5p/TGFBR2-SAMD2-SMAD3 Axis

Hepatocellular carcinoma (HCC) is a common malignancy with a poor prognosis. It has been proven that long non-coding RNAs (lncRNAs) play an essential role in regulating HCC progression. However, the involvement of LINC01094 in regulating epithelial-mesenchymal transition (EMT) in HCC remains unclear. LINC01094 expression in HCC patients was retrieved from the Cancer Genome Atlas database. Overexpressing and downregulating LINC01094 were conducted to investigate its biological functions using Hep3B, SNU-387, and HuH-7 cells. Western blotting and morphological observation were performed to study the EMT in HCC cells. Transwell assay was adopted to determine the migration and invasion of HCC cells. The underlying mechanism of competitive endogenous RNAs (ceRNAs) was investigated using bioinformatics analysis, quantitative reverse-transcription polymerase chain reaction, and rescue experiments. Elevated LINC01094 expression was observed in HCC and associated with a poor prognosis. Knockdown of LINC01094 expression in SNU-387 and HuH-7 cells could inhibit migration, invasion, and EMT markers. Overexpression of LINC01094 indicated that LINC01094 promoted EMT via the TGF-β/SMAD signaling pathway. The bioinformatics analysis revealed that miR-122-5p was a target of LINC01094. The miRWalk database analysis showed that TGFBR2, SMAD2, and SMAD3 were downstream targets of miR-122-5p. Mechanically, LINC01094 acted as a ceRNA that facilitated HCC metastasis by sponging miR-122-5p to regulate the expression of TGFBR2, SMAD2, and SMAD3. Further, TGF-β1 could enhance the expression of LINC01094, forming a positive feedback loop. TGF-β1-induced LINC01094 expression promotes HCC cell migration and invasion by targeting the miR-122-5p/TGFBR2-SMAD2-SMAD3 axis. LINC01094 may be a potential prognostic biomarker and therapeutic target for HCC metastasis.

Molecular insights and clinical implications for the tumor suppressor role of SCFFBXW7 E3 ubiquitin ligase

FBXW7 is one of the most well-characterized F-box proteins, serving as substrate receptor subunit of SKP1-CUL1-F-box (SCF) E3 ligase complexes. SCFFBXW7 is responsible for the degradation of various oncogenic proteins such as cyclin E, c-MYC, c-JUN, NOTCH, and MCL1. Therefore, FBXW7 functions largely as a major tumor suppressor. In keeping with this notion, FBXW7 gene mutations or downregulations have been found and reported in many types of malignant tumors, such as endometrial, colorectal, lung, and breast cancers, which facilitate the proliferation, invasion, migration, and drug resistance of cancer cells. Therefore, it is critical to review newly identified FBXW7 regulation and tumor suppressor function under physiological and pathological conditions to develop effective strategies for the treatment of FBXW7-altered cancers. Since a growing body of evidence has revealed the tumor-suppressive activity and role of FBXW7, here, we updated FBXW7 upstream and downstream signaling including FBXW7 ubiquitin substrates, the multi-level FBXW7 regulatory mechanisms, and dysregulation of FBXW7 in cancer, and discussed promising cancer therapies targeting FBXW7 regulators and downstream effectors, to provide a comprehensive picture of FBXW7 and facilitate the study in this field.

Long non-coding RNA PXN-AS1 promotes glutamine synthetase-mediated chronic myeloid leukemia BCR::ABL1-independent resistance to Imatinib via cell cycle signaling pathway

BACKGROUND

Chronic myeloid leukemia (CML) is a common hematological malignancy, and tyrosine kinase inhibitors (TKIs) represent the primary therapeutic approach for CML. Activation of metabolism signaling pathway has been connected with BCR::ABL1-independent TKIs resistance in CML cells. However, the specific mechanism by which metabolism signaling mediates this drug resistance remains unclear. Here, we identified one relationship between glutamine synthetase (GS) and BCR::ABL1-independent Imatinib resistance in CML cells.

METHODS

GS and PXN-AS1 in bone marrow samples of CML patients with Imatinib resistance (IR) were screened and detected by whole transcriptome sequencing. GS expression was upregulated using LVs and blocked using shRNAs respectively, then GS expression, Gln content, and cell cycle progression were respectively tested. The CML IR mice model were established by tail vein injection, prognosis of CML IR mice model were evaluated by Kaplan-Meier analysis, the ratio of spleen/body weight, HE staining, and IHC. PXN-AS1 level was blocked using shRNAs, and the effects of PXN-AS1 on CML IR cells in vitro and in vivo were tested the same as GS. Several RNA-RNA tools were used to predict the potential target microRNAs binding to both GS and PXN-AS1. RNA mimics and RNA inhibitors were used to explore the mechanism through which PXN-AS1 regulates miR-635 or miR-635 regulates GS.

RESULTS

GS was highly expressed in the bone marrow samples of CML patients with Imatinib resistance. In addition, the lncRNA PXN-AS1 was found to mediate GS expression and disorder cell cycle in CML IR cells via mTOR signaling pathway. PXN-AS1 regulated GS expression by binding to miR-635. Additionally, knockdown of PXN-AS1 attenuated BCR::ABL1-independent Imatinib resistance in CML cells via PXN-AS1/miR-635/GS/Gln/mTOR signaling pathway.

CONCLUSIONS

Thus, PXN-AS1 promotes GS-mediated BCR::ABL1-independent Imatinib resistance in CML cells via cell cycle signaling pathway.

The clinical significance of long non-coding RNAs MALAT1 and CASC2 in the diagnosis of HCV-related hepatocellular carcinoma

BACKGROUND

Globally, hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death due to a lack of early predictive and/or diagnostic tools. Thus, research for a new biomarker is important. LncRNAs play a functional role in target gene regulation and their deregulation is associated with several pathological conditions including HCC.

OBJECTIVE

This study aimed to explore the diagnostic potential of two LncRNAs MALAT1 and CASC2 in HCC compared to the routinely used diagnostic biomarker.

MATERIALS AND METHODS

The current study is a case-control study carried out at Fayoum University Hospital and conducted on 89 individuals. The study included three groups of 36 HCC patients on top of HCV(HCC/HCV), 33 HCV patients, and 20 healthy volunteers as a control group. All study subjects were subjected to radiological examinations. The determination of CBC was performed by the automated counter and liver function tests by the enzymatic method were performed. In addition, HCV RNA quantification and the expression level of two LncRNAs (MALAT1 and CASC2) were performed by qRT-PCR.

RESULTS

The results revealed a statistically significant difference between study groups regarding liver function tests with a higher mean in HCC/HCV group. Also, serum MALAT1 significantly up-regulated in HCV (11.2±2.8) and HCC/HCV (4.56±1.4) compared to the control group. Besides, serum CASC2 levels in the HCV group were significantly upregulated (14.9±3.6), while, downregulated in the HCC group (0.16± 0.03). Furthermore, The ROC analysis for diagnostic efficacy parameters indicated that CASC2 has higher accuracy (94.6%) and sensitivity (97.2%) for HCC diagnosis than AFP with an accuracy of (90.9%), sensitivity (69.4%), and MALAT1 showed an accuracy of (56.9%), sensitivity (72.2%).

CONCLUSION

Our study results indicated that CASC2 is a promising biomarker and is considered better and could help in HCC diagnosis on top of HCV than MALAT1 and the routine biomarker AFP.

Noncoding RNAs and programmed cell death in hepatocellular carcinoma: Significant role of epigenetic modifications in prognosis, chemoresistance, and tumor recurrence rate

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with a high death rate in the world. The molecular mechanisms related to the pathogenesis of HCC have not been precisely defined so far. Hence, this review aimed to address the potential cross-talk between noncoding RNAs (ncRNAs) and programmed cell death in HCC. All related papers in the English language up to June 2023 were collected and screened. The searched keywords in scientific databases, including Scopus, PubMed, and Google Scholar, were HCC, ncRNAs, Epigenetic, Programmed cell death, Autophagy, Apoptosis, Ferroptosis, Chemoresistance, Tumor recurrence, Prognosis, and Prediction. According to the reports, ncRNAs, comprising long ncRNAs, microRNAs, circular RNAs, and small nucleolar RNAs can affect cell proliferation, migration, invasion, and metastasis, as well as cell death-related processes, such as autophagy, ferroptosis, necroptosis, and apoptosis in HCC by regulating cancer-associated genes and signaling pathways, for example, phosphoinositide 3-kinase/Akt, extracellular signal-regulated kinase/MAPK, and Wnt/β-catenin signaling pathways. It seems that ncRNAs, as epigenetic regulators, can be utilized as biomarkers in diagnosis, prognosis, survival and recurrence rates prediction, chemoresistance, and evaluation of therapeutic response in HCC patients. However, more scientific evidence is suggested to be accomplished to confirm these results.

LINC00540 promotes sorafenib resistance and functions as a ceRNA for miR-4677-3p to regulate AKR1C2 in hepatocellular carcinoma

Sorafenib resistance is one of the main causes of poor prognosis in patients with advanced hepatocellular carcinoma (HCC). Long noncoding RNAs (lncRNAs) function as suppressors or oncogenic factors during tumor progression and drug resistance. Here, to identify therapeutic targets for HCC, the biological mechanisms of abnormally expressed lncRNAs were examined in sorafenib-resistant HCC cells. Specifically, we established sorafenib-resistant HCC cell lines (Huh7-S and SMMC7721-S), which displayed an epithelial-mesenchymal transition (EMT) phenotype. Transcriptome sequencing (RNA-Seq) was performed to established differential lncRNA expression profiles for sorafenib-resistant cells. Through this analysis, we identified LINC00540 as significantly up-regulated in sorafenib-resistant cells and a candidate lncRNA for further mechanistic investigation. Functionally, LINC00540 knockdown promoted sorafenib sensitivity and suppressed migration, invasion, EMT and the activation of PI3K/AKT signaling pathway in sorafenib-resistant HCC cells, whereas overexpression of LINC00540 resulted in the opposite effects in parental cells. LINC00540 functions as a competing endogenous RNA (ceRNA) by competitively binding to miR-4677-3p , thereby promoting AKR1C2 expression. This is the first study that demonstrates a role for LINC00540 in enhancing sorafenib resistance, migration and invasion of HCC cells through the LINC00540/miR-4677-3p/AKR1C2 axis, suggesting that LINC00540 may represent a potential therapeutic target and prognosis biomarker for HCC.

The role of long non-coding RNA in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent liver malignancy with complex etiology and generally poor prognosis. Recently, long non-coding RNAs (lncRNAs), non-protein-coding RNA molecules exceeding 200 nucleotides, have emerged as pivotal players in HCC, influencing its initiation, progression, invasion, and metastasis. These lncRNAs modulate gene expression at epigenetic, transcriptional, and post-transcriptional levels, actively participating in the pathological and physiological processes of HCC. Understanding the intricate relationship between lncRNAs and HCC is important for improving prognosis and reducing mortality. This review summarizes advancements in elucidating the role of lncRNAs in HCC pathogenesis.

Long Non-Coding RNA Dancr Affects Myocardial Fibrosis in Atrial Fibrillation Mice via the MicroRNA-146b-5p/Smad5 Axis

Objectives

Atrial fibrillation (AF) is the most frequent arrhythmia, and myocardial fibrosis (MF) has a close association with atrial remodeling and leads to AF. This study aimed to explore the function of the long non-coding RNA (lncRNA) differentiation antagonizing non-protein coding RNA (Dancr)/microRNA (miR)-146b-5p/Smad5 axis on MF in AF mice.

Methods

AF mouse models were established. Overexpression Dancr lentivirus was injected into AF mice to increase Dancr expression in myocardial tissues. LncRNA Dancr, miR-146b-5p, and Smad5 expression levels and inflammatory factors (IL-18 and TNF-α) in the myocardial tissues were measured. MF was measured and the expression levels of MF-related genes (COL1A1, α-SMA, and FN1) were detected. In addition, in vitro HL-1 cell rapid pacing models were constructed, and after lncRNA Dancr and miR-146b-5p-related construct transfection, cell viability and cell apoptosis were determined.

Results

LncRNA Dancr up-regulation ameliorated MF in the AF mice, reduced IL-18 and TNF-α expression levels in myocardial tissues, and decreased COL1A1, α-SMA, and FN1 expression levels. The in vitro HL-1 cell rapid pacing models suggested that miR-146b-5p overexpression reversed the inhibitory effects of lncRNA Dancr overexpression on MF in HL-1 cells, and Smad5 interference reversed the ameliorative effects of miR-146b-5p interference on MF in HL-1 cells.

Conclusions

LncRNA Dancr can sponge miR-146b-5p to promote Smad5 expression, thereby delaying MF in AF mice.

lncRNA MSTRG4710 Promotes the Proliferation and Differentiation of Preadipocytes through miR-29b-3p/IGF1 Axis

Obesity, a major global health issue, is increasingly associated with the integral role of long non-coding RNA (lncRNA) in adipogenesis. Recently, we found that lncRNA-MSTRG4710 was highly expressed in the liver of rabbits fed a high-fat diet, but whether it is involved in lipid metabolism remains unclear. A series of experiments involving CCK-8, EDU, qPCR, and Oil Red O staining demonstrated that the overexpression of MSTRG4710 stimulated the proliferation and differentiation of preadipocytes while its knockdown inhibited these processes. Bioinformatics analysis showed that miR-29b-3p was a potential target gene of MSTRG4710, and IGF1 was a downstream target gene of miR-29b-3p. Luciferase reporter gene analysis and qPCR analysis confirmed that miR-29b-3p was a potential target gene of MSTRG4710, and miR-29b-3p directly targeted the 3'UTR of IGF1. The overexpression of miR-29b-3p was observed to regulate IGF1 protein and mRNA levels negatively. Additionally, a total of 414 known differentially expressed genes between the miR-29b-3p mimic, miR-29b-3p negative control (NC), siMSTRG4710, and siMSTRG4710-NC group were screened via transcriptome sequencing technology. The GO- and KEGG-enriched pathways were found to be related to lipid metabolism. The study also established that miR-29b-3p targets IGF1 to inhibit preadipocyte proliferation and differentiation. Notably, IGF1 knockdown significantly reduced preadipocyte proliferation and differentiation. Furthermore, co-transfection of pcDNA3.1(+)-MSTRG4710 and mimics into rabbit preadipocytes revealed that the mimics reversed the promotional effect of pcDNA3.1(+)-MSTRG4710. In conclusion, these results uncover that MSTRG4710 positively regulated cell proliferation and adipogenesis by the miR-29b-3p/IGF1 axis. Our findings might provide a new target for studying adipogenesis in rabbit preadipocytes and obesity.

Decoding hepatocarcinogenesis from a noncoding RNAs perspective

Being a leading lethal malignancy worldwide, the pathophysiology of hepatocellular carcinoma (HCC) has gained a lot of interest. Yet, underlying mechanistic basis of the liver tumorigenesis is poorly understood. The role of some coding genes and their respective translated proteins, then later on, some noncoding RNAs (ncRNAs) such as microRNAs have been extensively studied in context of HCC pathophysiology; however, the implication of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in HCC is indeed less investigated. As a subclass of the ncRNAs which has been elusive for long time ago, lncRNAs was found to be involved in plentiful cellular functions such as DNA, RNA, and proteins regulation. Hence, it is undisputed that lncRNAs dysregulation profoundly contributes to HCC via diverse etiologies. Accordingly, lncRNAs represent a hot research topic that requires prime focus in HCC. In this review, the authors discuss breakthrough discoveries involving lncRNAs and circRNAs dysregulation that have contributed to the contemporary concepts of HCC pathophysiology and how these concepts could be leveraged as potential novel diagnostic and prognostic HCC biomarkers. Further, this review article sheds light on future trends, thereby discussing the pathological roles of lncRNAs and circRNAs in HCC proliferation, migration, and epithelial-to-mesenchymal transition. Along this line of reasoning, future recommendations of how these targets could be exploited to achieve effective HCC-related drug development is highlighted.

The expression of lncRNAs CASC2, NEAT1, LINC00299 in breast cancer tissues and their relationship with the XBP1 splicing rate in Iranian patients during 2014-2019: A cross-sectional study

Background and Aims

Breast cancer is a leading cause of incidence and mortality in women globally. Identifying new molecular markers can aid in cancer diagnosis, targeted therapy, and treatment monitoring. This study aimed to measure the expression of the X-box binding protein 1 (XBP1) gene, an index of the unfolded protein response (UPR), and long noncoding RNAs (lncRNAs), including Nuclear Enriched Abundant Transcript 1 (NEAT1), Cancer Susceptibility Candidate 2 (CASC2), and Long Intergenic Nonprotein Coding RNA 299 (LINC00299), as possible regulators of the UPR pathway.

Methods

Total RNA was extracted from 40 samples of breast tumor tissues and their respective controls. The expression level of lncRNAs CASC2, NEAT1, and LINC00299 was quantified using reverse transcription-polymerase chain reaction (RT-PCR). The ratio of the spliced form of XBP1 to its unspliced form (XBP1u) was determined by PCR and electrophoresis.

Results

The results showed a 2.8-fold increase in the ratio of XBP1s/u in breast cancer tissues compared to adjacent nonmalignant samples (p < 0.05). Additionally, the level of lncRNAs NEAT1, CASC2, and LINC00299 in breast tumor tissues increased significantly by twofold, 1.5-fold, and 2.3-fold, respectively, compared to adjacent nonmalignant samples (p < 0.05).

Conclusions

Based on the association between the expression of lncRNAs CASC2, LINC00299, and NEAT1 and the XBP1s/u ratio, these lncRNAs could be potential regulators of the UPR pathway. Also, CASC2 and NEAT1 genes could be suggested as suitable biomarkers to distinguish cancerous tissue from noncancerous breast tissue due to their significant increase in expression in cancerous samples compared to adjacent noncancerous.

Differentially expressed non-coding RNAs and their regulatory networks in liver cancer

The vast majority of human transcriptome is represented by various types of small RNAs with little or no protein-coding capability referred to as non-coding RNAs (ncRNAs). Functional ncRNAs include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), which are expressed at very low, but stable and reproducible levels in a variety of cell types. ncRNAs regulate gene expression due to miRNA capability of complementary base pairing with mRNAs, whereas lncRNAs and circRNAs can sponge miRNAs off their target mRNAs to act as competitive endogenous RNAs (ceRNAs). Each miRNA can target multiple mRNAs and a single mRNA can interact with several miRNAs, thereby creating miRNA-mRNA, lncRNA-miRNA-mRNA, and circRNA-miRNA-mRNA regulatory networks. Over the past few years, a variety of differentially expressed miRNAs, lncRNAs, and circRNAs (DEMs, DELs, and DECs, respectively) have been linked to cancer pathogenesis. They can exert both oncogenic and tumor suppressor roles. In this review, we discuss the recent advancements in uncovering the roles of DEMs, DELs, and DECs and their networks in aberrant cell signaling, cell cycle, transcription, angiogenesis, and apoptosis, as well as tumor microenvironment remodeling and metabolic reprogramming during hepatocarcinogenesis. We highlight the potential and challenges in the use of differentially expressed ncRNAs as biomarkers for liver cancer diagnosis and prognosis.

The Role of FBXW7 in Gynecologic Malignancies

The F-Box and WD Repeat Domain Containing 7 (FBXW7) protein has been shown to regulate cellular growth and act as a tumor suppressor. This protein, also known as FBW7, hCDC4, SEL10 or hAGO, is encoded by the gene FBXW7. It is a crucial component of the Skp1-Cullin1-F-box (SCF) complex, which is a ubiquitin ligase. This complex aids in the degradation of many oncoproteins, such as cyclin E, c-JUN, c-MYC, NOTCH, and MCL1, via the ubiquitin-proteasome system (UPS). The FBXW7 gene is commonly mutated or deleted in numerous types of cancer, including gynecologic cancers (GCs). Such FBXW7 mutations are linked to a poor prognosis due to increased treatment resistance. Hence, detection of the FBXW7 mutation may possibly be an appropriate diagnostic and prognostic biomarker that plays a central role in determining suitable individualized management. Recent studies also suggest that, under specific circumstances, FBXW7 may act as an oncogene. There is mounting evidence indicating that the aberrant expression of FBXW7 is involved in the development of GCs. The aim of this review is to give an update on the role of FBXW7 as a potential biomarker and also as a therapeutic target for novel treatments, particularly in the management of GCs.

Hypoxia-induced lncRNA MRVI1-AS1 accelerates hepatocellular carcinoma progression by recruiting RNA-binding protein CELF2 to stabilize SKA1 mRNA

BACKGROUND

Long non-coding RNAs (lncRNAs) perform a vital role during the progression of hepatocellular carcinoma (HCC). Here, we aimed to identify a novel lncRNA involved in HCC development and elucidate the underlying molecular mechanism.

METHODS

The RT-qPCR and TCGA dataset analysis were applied to explore the expressions of MRVI1-AS1 in HCC tissues and cell lines. Statistical analysis was applied to analyze the clinical significance of MRVI1-AS1 in HCC. The functions of MRVI1-AS1 in HCC cells metastasis and growth were explored by transwell assays, wound healing assay, MTT assay, EdU assay, the intravenous transplantation tumor model, and the subcutaneous xenograft tumor model. Microarray mRNA expression analysis, dual luciferase assays, and actinomycin D treatment were used to explore the downstream target of MRVI1-AS1 in HCC cells. RIP assay was applied to assess the direct interactions between CELF2 and MRVI1-AS1 or SKA1 mRNA. Rescue experiments were employed to validate the functional effects of MRVI1-AS1, CELF2, and SKA1 on HCC cells.

RESULTS

MRVI1-AS1 was found to be dramatically upregulated in HCC and the expression was strongly linked to tumor size, venous infiltration, TNM stage, as well as HCC patients' outcome. Cytological experiments and animal experiments showed that MRVI1-AS1 promoted HCC cells metastasis and growth. Furthermore, SKA1 was identified as the downstream targeted mRNA of MRVI1-AS1 in HCC cells, and MRVI1-AS1 increased SKA1 expression by recruiting CELF2 protein to stabilize SKA1 mRNA. In addition, we found that MRVI1-AS1 expression was stimulated by hypoxia through a HIF-1-dependent manner, which meant that MRVI1-AS was a direct downstream target gene of HIF-1 in HCC.

CONCLUSION

In a word, our findings elucidated that hypoxia-induced MRVI1-AS1 promotes metastasis and growth of HCC cells via recruiting CELF2 protein to stabilize SKA1 mRNA, pointing to MRVI1-AS1 as a promising clinical application target for HCC therapy.

FBXW7 attenuates tumor drug resistance and enhances the efficacy of immunotherapy

FBXW7 (F-box and WD repeat domain containing 7) is a critical subunit of the Skp1-Cullin1-F-box protein (SCF), acting as an E3 ubiquitin ligase by ubiquitinating targeted protein. Through degradation of its substrates, FBXW7 plays a pivotal role in drug resistance in tumor cells and shows the potential to rescue the sensitivity of cancer cells to drug treatment. This explains why patients with higher FBXW7 levels exhibit higher survival times and more favorable prognosis. Furthermore, FBXW7 has been demonstrated to enhance the efficacy of immunotherapy by targeting the degradation of specific proteins, as compared to the inactivated form of FBXW7. Additionally, other F-box proteins have also shown the ability to conquer drug resistance in certain cancers. Overall, this review aims to explore the function of FBXW7 and its specific effects on drug resistance in cancer cells.

LncRNA CASC2 Regulate Cell Proliferation and Invasion by Targeting miR-155/SOCS1 Axis in Hepatocellular Carcinoma

Long noncoding RNAs (lncRNAs) have been reported to be involved in the development and progression of various human malignancies. However, the role of lncRNA CASC2 in hepatocellular carcinoma (HCC) remains mostly unknown. The aim of this study was to investigate the potential roles and underlying mechanisms of CASC2 in HCC progression. We found that CASC2 expressions were downregulated in HCC tissue samples and cell lines. The clinical assays revealed that lower levels of CASC2 were associated with the TNM stage, lymph node metastasis, and a poorer prognosis specific to HCC patients. Overexpression of CASC2 inhibited the proliferating, migratory, and invasion capacity of HCC cells. Bioinformatics analysis and the luciferase reporter assay revealed that CASC2 worked as a molecular sponge for miR-155. And CASC2 could upregulate SOCS1 expression by inhibiting miR-155 expression in HCC cells. Furthermore, SOCS1 inhibition partially inverses the suppression effect of cell proliferation, migration, and invasion regulated by CASC2 in Huh7 and HepG2 cells. Taken together, our findings identified CASC2 as a tumor suppressor to inhibit HCC development by regulating the miR-155/SOCS1 axis, and CASC2 might be a potential therapeutic target of HCC for future clinical treatment.

Epigenetic inhibition of lncRNA GMDS-AS1 by methyltransferase ESET promoted cell viability and metastasis of hepatocellular carcinoma

BACKGROUND

Long noncoding RNA (lncRNAs) GMDS-AS1 has been reported as a tumor regulator in tumor growth and metastasis, but its effect in hepatocellular carcinoma (HCC) remains unclear. ESET, a histone H3K9 methyl-transferase, is involved in epigenomic regulation of tumor progression in multiple cancers. However, the correlation between ESET and lncRNA in HCC is less reported.

METHODS

Quantitative real-time PCR (qRT-PCR) was taken to determine the expression of ESET and GMDS-AS1. Western blot was taken to determine the target protein levels of ESET and GMDS-AS1. Online database and bioinformatics analysis were used to screen abnormally expressed genes. Luciferase assay was performed to confirm the binding of GMDS-AS1 and PSMB1. Ki67 and Edu were used for evaluated the proliferation of tumor cells. ChIP assay was performed to verify the relationship between H3K9me1 and lncRNA GMDS-AS1 promoter. Transwell was taken to determine the migration and invasion ability of tumor cells. CCK-8 was used for determining the viability of tumor cells. Flow cytometry was performed to detect the cell cycle of tumor cells.

RESULTS

The expression of GMDS-AS1 was decreased and the expression of ESET was increased in HCC. GMDS-AS1 inhibition contributed to tumor development, and this effect was closely related to epigenetic inhibition of GMDS-AS1 by ESET. PSMB1, a downstream target of GMDS-AS1, promoted the tumor proliferation and was negatively regulated by GMDS-AS1.

CONCLUSION

Our result demonstrates anti-tumorigenic traits of lncRNA GMDS-AS1 in HCC and explains its pattern of regulation mediated by ESET. Our work unmasked an essential role of GMDS-AS1 in HCC progression and detected a novel pathway for ESET to promote HCC.

Long Non-Coding RNAs as Novel Targets for Phytochemicals to Cease Cancer Metastasis

Metastasis is a multi-step phenomenon during cancer development leading to the propagation of cancer cells to distant organ(s). According to estimations, metastasis results in over 90% of cancer-associated death around the globe. Long non-coding RNAs (LncRNAs) are a group of regulatory RNA molecules more than 200 base pairs in length. The main regulatory activity of these molecules is the modulation of gene expression. They have been reported to affect different stages of cancer development including proliferation, apoptosis, migration, invasion, and metastasis. An increasing number of medical data reports indicate the probable function of LncRNAs in the metastatic spread of different cancers. Phytochemical compounds, as the bioactive agents of plants, show several health benefits with a variety of biological activities. Several phytochemicals have been demonstrated to target LncRNAs to defeat cancer. This review article briefly describes the metastasis steps, summarizes data on some well-established LncRNAs with a role in metastasis, and identifies the phytochemicals with an ability to suppress cancer metastasis by targeting LncRNAs.

Long non-coding RNAs (lncRNAs) in hepatocellular carcinoma progression: Biological functions and new therapeutic targets

Liver is an important organ in body that performs vital functions such as detoxification. Liver is susceptible to development of cancers, and hepatocellular carcinoma (HCC) is among them. 75-85% of liver cancer cases are related to HCC. Therefore, much attention has been directed towards understanding factors mediating HCC progression. LncRNAs are epigenetic factors with more than 200 nucleotides in length located in both nucleus and cytoplasm and they are promising candidates in cancer therapy. Directing studies towards understanding function of lncRNAs in HCC is of importance. LncRNAs regulate cell cycle progression and growth of HCC cells, and they can also induce/inhibit apoptosis in tumor cells. LncRNAs affect invasion and metastasis in HCC mainly by epithelial-mesenchymal transition (EMT) mechanism. Revealing the association between lncRNAs and downstream signaling pathways in HCC is discussed in the current manuscript. Infectious diseases can affect lncRNA expression in mediating HCC development and then, altered expression level of lncRNA is associated with drug resistance and radio-resistance. Biomarker application of lncRNAs and their role in prognosis and diagnosis of HCC are also discussed to pave the way for treatment of HCC patients.

LncRNA RPPH1 acts as a molecular sponge for miR-122 to regulate Wnt1/β-catenin signaling in hepatocellular carcinoma

This study aimed to explore the role of lncRNA RPPH1 in hepatocellular carcinoma. The expression of RPPH1 and miR-122 was determined by Real-time PCR. Cell proliferation and colony formation assays were employed to monitor cell growth in vitro. Wound healing and Transwell assays were applied to detect cell migration and invasion. A dual-luciferase reporter assay was used to verify the interaction between RPPH1 and miR-122. The in vivo function of RPPH1 was illustrated by xenograft tumor models. The results showed that the expression of RPPH1 was markedly upregulated in human HCC specimens and cell lines compared to normal controls. However, the trend of miR-122 was the opposite. RPPH1 facilitates the proliferation, migration, and invasion of HCC cells and synchronously suppresses cell apoptosis. The dual-luciferase assay confirmed the relationship between RPPH1 and miR-122. Rescue experiments showed that RPPH1 acted as a competing endogenous RNA (ceRNA) by sponging miR-122 in HCC cells. Moreover, RPPH1 positively regulated the expression of Wnt1 and its downstream targets through miR-122. Our study demonstrates for the first time that RPPH1 promotes HCC progression via the miR-122/Wnt1/β-catenin axis, which may represent a valuable therapeutic target for patients with HCC.

The roles of lncRNA functions and regulatory mechanisms in the diagnosis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent and deadly type of liver cancer. While the underlying molecular mechanisms are poorly understood, it is documented that lncRNAs may play key roles. Many HCC-associated lncRNAs have been linked to HBV and HCV infection, mediating gene expression, cell growth, development, and death. Studying the regulatory mechanisms and biological functions of HCC-related lncRNAs will assist our understanding of HCC pathogenesis as well as its diagnosis and management. Here, we address the potential of dysregulated lncRNAs in HCC as diagnostic and therapeutic biomarkers, and we evaluate the oncogenic or tumor-suppressive properties of these lncRNAs.

Value of biomarkers in epithelial-mesenchymal transition models of liver cancer under different interventions: a meta-analysis

Aim: A meta-analysis was conducted to evaluate the effectiveness of crucial biomarkers in HepG2 cells during epithelial-mesenchymal transformation induced by multiple interventions. Methods: PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wan Fang Data and VIP databases were systematically searched from inception to 14 June 2020, by two independent reviewers. Results: A total of 58 studies were included in the meta-analysis. E-cadherin, N-cadherin and vimentin performed well under medicinal interventions. E-cadherin worked well under genetic interventions. E-cadherin and N-cadherin also performed significantly well under tumor microenvironment interventions. Under ncRNA interventions, the expression of E-cadherin significantly changed. Conclusion: Different sets of biomarkers should be selected under various interventions based on their performance.

Hypoxia-induced LINC00674 facilitates hepatocellular carcinoma progression by activating the NOX1/mTOR signaling pathway

The hypoxic tumor microenvironment, a fundamental feature of solid tumors, drives hepatocellular carcinoma (HCC) progression through regulating the transcriptional activities of protein-coding and noncoding genes. However, long noncoding RNA (lncRNA)-mediated HCC progression in hypoxic microenvironment remains largely unknown yet. In this study, we found that LINC00674 was upregulated under hypoxic conditions in a HIF-1-dependent manner, and the occupancy of HIF-1 to HRE of LINC00674 gene promoter was essential for its transcription. In addition, LINC00674 level was increased in HCC cell lines and tissues. Clinically, statistical analysis showed that LINC00674 expression was significantly associated with tumor size, venous infiltration, tumor stage and poor prognosis of HCC. Functionally, loss-of-function assays revealed that LINC00674 knockdown inhibited the migration, proliferation and invasion of HCC cells. Furthermore, LINC00674 silencing prominently repressed the mTOR signaling pathway. LINC00674 overexpression-enhanced HCC cell proliferation, migration and invasion were markedly abolished by an mTOR inhibitor rapamycin. NADPH oxidase 1 (NOX1) was positively regulated by LINC00674 in HCC cells. NOX1 knockdown markedly reversed LINC00674-upregulated the p-mTOR level and HCC cells' malignant behaviors. Finally, we found that LINC00674 knockdown attenuated the growth of HCC cells in vivo. Our finding demonstrated that LINC00674 was a new HIF-1 target gene, and hypoxia-induced LINC00674 exerted a pro-proliferative and pro-metastatic role in HCC, possibly by activating the NOX1/mTOR signaling pathway. This study suggested LINC00674 as a promising therapeutic target for HCC.

The functions of long noncoding RNAs on regulation of F-box proteins in tumorigenesis and progression

Accumulated evidence has revealed that F-box protein, a subunit of SCF E3 ubiquitin ligase complexes, participates in carcinogenesis and tumor progression via targeting its substrates for ubiquitination and degradation. F-box proteins could be regulated by cellular signaling pathways and noncoding RNAs in tumorigenesis. Long noncoding RNA (lncRNA), one type of noncoding RNAs, has been identified to modulate the expression of F-box proteins and contribute to oncogenesis. In this review, we summarize the role and mechanisms of multiple lncRNAs in regulating F-box proteins in tumorigenesis, including lncRNAs SLC7A11-AS1, MT1JP, TUG1, FER1L4, TTN-AS1, CASC2, MALAT1, TINCR, PCGEM1, linc01436, linc00494, GATA6-AS1, and ODIR1. Moreover, we discuss that targeting these lncRNAs could be helpful for treating cancer via modulating F-box protein expression. We hope our review can stimulate the research on exploration of molecular insight into how F-box proteins are governed in carcinogenesis. Therefore, modulation of lncRNAs is a potential therapeutic strategy for cancer therapy via regulation of F-box proteins.

Emerging roles and potential clinical applications of long non-coding RNAs in hepatocellular carcinoma

Hepatocellular carcinoma is one of the most common highly malignant tumors in humans, as well as the leading cause of cancer-related death worldwide. Growing evidence has indicated that lncRNAs are implicated in different molecular mechanisms, including interactions with DNA, RNA, or protein, so that to regulate the gene expression at epigenetic, transcriptional, or posttranscriptional level. Moreover, the mechanism of action of lncRNA is closely related to its subcellular localization. An increasing number of studies have certified that lncRNA plays a significant biological function in the occurrence and development of hepatocellular carcinoma, such as involving in cell proliferation, metastasis, apoptosis, ferroptosis, autophagy, and reprogramming of energy metabolism. As a result, lncRNA has great potential as a novel biomarker for diagnosis or therapeutics of hepatocellular carcinoma. In this review, we highlight the correlation between subcellular localization of lncRNA and its mechanism of action, discuss the biological roles of lncRNA and the latest research advances in hepatocellular carcinoma, and emphasize the potential of lncRNA as a therapeutic target for advanced patients of hepatocellular carcinoma.

Recent Insight on Regulations of FBXW7 and Its Role in Immunotherapy

SCF^FBXW7 E3 ubiquitin ligase complex is a crucial enzyme of the ubiquitin proteasome system that participates in variant activities of cell process, and its component FBXW7 (F-box and WD repeat domain–containing 7) is responsible for recognizing and binding to substrates. The expression of FBXW7 is controlled by multiple pathways at different levels. FBXW7 facilitates the maturity and function maintenance of immune cells via functioning as a mediator of ubiquitination-dependent degradation of substrate proteins. FBXW7 deficiency or mutation results in the growth disturbance and dysfunction of immune cell, leads to the resistance against immunotherapy, and participates in multiple illnesses. It is likely that FBXW7 coordinating with its regulators and substrates could offer potential targets to improve the sensitivity and effects of immunotherapy. Here, we review the mechanisms of the regulation on FBXW7 and its tumor suppression role in immune filed among various diseases (mostly cancers) to explore novel immune targets and treatments.

Non-coding RNAs regulating epithelial-mesenchymal transition: Research progress in liver disease

Chronic liver injury could gradually progress to liver fibrosis, cirrhosis, and even hepatic carcinoma without effective treatment. The massive production and activation of abnormal cell differentiation is vital to the procession of liver diseases. Epithelial-mesenchymal transformation (EMT) is a biological process in which differentiated epithelial cells lose their epithelial characteristics and acquire mesenchymal cell migration capacity. Emerging evidence suggests that EMT not only occurs in the process of hepatocellular carcinogenesis, but also appears in liver cells transforming to myofibroblasts, a core event of liver disease. Non-coding RNA (ncRNA) such as microRNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA) are important regulatory factors in EMT, which can regulate target gene expression by binding with RNA single-stranded. Various studies had shown that ncRNA regulation of EMT plays a key role in liver disease development, and many effective ncRNAs have been identified as promising biomarkers for the diagnosis and treatment of liver disease. In this review, we focus on the relationship between the different ncRNAs and EMT as well as the specific molecular mechanism in the liver diseases to enrich the pathological progress of liver diseases and provide reference for the treatment of liver diseases.

Identification of an Epithelial-Mesenchymal Transition-Related Long Non-coding RNA Prognostic Signature to Determine the Prognosis and Drug Treatment of Hepatocellular Carcinoma Patients

Introduction

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with poor prognosis. Epithelial–mesenchymal transition (EMT) is crucial for cancer progression and metastasis. Thus, we aimed to construct an EMT-related lncRNA signature for predicting the prognosis of HCC patients.

Methods

Cox regression analysis and LASSO regression method were used to build an EMT-related lncRNAs risk signature based on TCGA database. Kaplan-Meier survival analysis was conducted to compare the overall survival (OS) in different risk groups. ROC curves and Cox proportional-hazards analysis were performed to evaluate the performance of the risk signature. RT-qPCR was conducted in HCC cell lines and tissue samples to detect the expression of some lncRNAs in this risk model. Furthermore, a nomogram involving the risk score and clinicopathological features was built and validated with calibration curves and ROC curves. In addition, we explored the association between risk signature and tumor immunity, somatic mutations status, and drugs sensitivity.

Results

Twelve EMT-related lncRNAs were obtained to construct the prognostic risk signature for patients with HCC. The Kaplan-Meier curve analysis revealed that patients in the high-risk group had worse overall survival (OS) than those in low-risk group. ROC curves and Cox regression analysis suggested the risk signature could predict HCC survival exactly and independently. The prognostic value of the risk model was confirmed in the testing and entire groups. We also found AC099850.3 and AC092171.2 were highly expressed in HCC cells and HCC tissues. The nomogram could accurately predict survival probability of HCC patients. Gene set enrichment analysis (GSEA) and gene ontology (GO) analysis showed that cancer-related pathways and cell division activity were enriched in high-risk group. The SNPs showed that the prevalence of TP53 mutations was significantly different between high- and low-risk groups; the TP53 mutations and the high TMB were both associated with a worse prognosis in patients with HCC. We also observed widely associations between risk signature and drugs sensitivity in HCC.

Conclusion

A novel EMT-related lncRNAs risk signature, including 12 lncRNAs, was established and identified in patients with HCC, which can accurately predict the prognosis of HCC patients and may be used to guide individualized treatment in the clinical practice.

FBXW7 and the Hallmarks of Cancer: Underlying Mechanisms and Prospective Strategies

FBXW7, a member of the F-box protein family within the ubiquitin–proteasome system, performs an indispensable role in orchestrating cellular processes through ubiquitination and degradation of its substrates, such as c-MYC, mTOR, MCL-1, Notch, and cyclin E. Mainly functioning as a tumor suppressor, inactivation of FBXW7 induces the aberrations of its downstream pathway, resulting in the occurrence of diseases especially tumorigenesis. Here, we decipher the relationship between FBXW7 and the hallmarks of cancer and discuss the underlying mechanisms. Considering the interplay of cancer hallmarks, we propose several prospective strategies for circumventing the deficits of therapeutic resistance and complete cure of cancer patients.

Clinical significance of FBXW7 loss of function in human cancers

FBXW7 (F-Box and WD Repeat Domain Containing 7) (also referred to as FBW7 or hCDC4) is a component of the Skp1-Cdc53 / Cullin-F-box-protein complex (SCF/β-TrCP). As a member of the F-box protein family, FBXW7 serves a role in phosphorylation-dependent ubiquitination and proteasome degradation of oncoproteins that play critical role(s) in oncogenesis. FBXW7 affects many regulatory functions involved in cell survival, cell proliferation, tumor invasion, DNA damage repair, genomic instability and telomere biology. This thorough review of current literature details how FBXW7 expression and functions are regulated through multiple mechanisms and how that ultimately drives tumorigenesis in a wide array of cell types. The clinical significance of FBXW7 is highlighted by the fact that FBXW7 is frequently inactivated in human lung, colon, and hematopoietic cancers. The loss of FBXW7 can serve as an independent prognostic marker and is significantly correlated with the resistance of tumor cells to chemotherapeutic agents and poorer disease outcomes. Recent evidence shows that genetic mutation of FBXW7 differentially affects the degradation of specific cellular targets resulting in a distinct and specific pattern of activation/inactivation of cell signaling pathways. The clinical significance of FBXW7 mutations in the context of tumor development, progression, and resistance to therapies as well as opportunities for targeted therapies is discussed.

All-Ion Monitoring-Directed Low-Abundance Protein Quantification Reveals CALB2 as a Key Promoter in Hepatocellular Carcinoma Metastasis

Because of the wide abundance range of the proteome, achieving high-coverage quantification of low-abundance proteins is always a major challenge. In this study, a complete pipeline focused on all-ion monitoring (AIM) is first constructed with the concept of untargeted parallel-reaction monitoring, including the seamless connection of protein sample preparation, liquid chromatography mass spectrometry (LC-MS) acquisition, and algorithm development to enable the in-depth quantitative analysis of low-abundance proteins. This pipeline significantly improves the reproducibility and sensitivity of sample preparation and LC-MS acquisition for low-abundance proteins, enabling all the precursors ions fragmented and collected. Contributed by the advantages of the AIM method with all the target precursor acquisition by the data-dependent acquisition (DDA) approach, together with the ability of data-independent acquisition to fragment all precursor ions, the quantitative accuracy and precision of low-abundance proteins are greatly enhanced. As a proof of concept, this pipeline is employed to discover the key differential proteins in the mechanism of hepatocellular carcinoma (HCC) metastasis. On the basis of the superiority of AIM, an extremely low-abundance protein, CALB2, is proposed to promote HCC metastasis in vitro and in vivo. We also reveal that CALB2 activates the TRPV2-Ca²⁺-ERK1/2 signaling pathway to induce HCC cell metastasis. In summary, we provide a universal AIM pipeline for the high-coverage quantification of low-abundance functional proteins to seek novel insights into the mechanisms of cancer metastasis.

Long non-coding RNA OIP5-AS1 suppresses microRNA-92a to augment proliferation and metastasis of ovarian cancer cells through upregulating ITGA6

OBJECTIVE

Recently, long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been identified as essential biomarkers during development of malignancies. This study was performed to study the roles of lncRNA opa-interacting protein 5 antisense transcript 1 (OIP5-AS1) and miR-92a in ovarian cancer (OC).

METHODS

OIP5-AS1, miR-92a and integrin alpha 6 (ITGA6) expression in OC tissues and cells was assessed. The screened OC cells were respectively with OIP5-AS1-, miR-92a- and ITGA6-related vectors or oligonucleotides . The viability, migration, invasion and apoptosis of the cells were determined and the levels of epithelial-mesenchymal transition (EMT)-related proteins were also measured. The interactions between OIP5-AS1 and miR-92a, and between miR-92a and ITGA6 were confirmed.

RESULTS

OIP5-AS1 and ITGA6 were upregulated while miR-92a was downregulated in OC. Inhibited OIP5-AS1 or downregulated ITGA6 or elevated miR-92a repressed EMT, viability, migration and invasion, and promoted apoptosis of OC cells. OIP5-AS1 as a competing endogenous RNA interacted with miR-92a to regulate ITGA6. These effects that induced by silenced OIP5-AS1 could be reversed by miR-92a inhibition while those that induced by up-regulated miR-92a were reduced by restored ITGA6.

CONCLUSION

OIP5-AS1 silencing promoted miR-92a to repress proliferation and metastasis of OC cells through inhibiting ITGA6.

Long non‑coding RNA LINC00238 suppresses the malignant phenotype of liver cancer by sponging miR‑522

Long non‑coding RNAs can regulate the malignant tumor phenotype either as tumor suppressors or oncogenes. The present study investigated the underlying mechanism of LINC00238 in liver cancer. LINC00238 was identified as a downregulated molecule in The Cancer Genome Atlas liver hepatocellular carcinoma dataset through Gene Expression Profiling Interactive Analysis software. Through gain‑ and loss‑of‑function experiments, LINC00238 was confirmed as a tumor suppressor that could not only decrease cell viability, migration and invasion in vitro, but also tumorigenesis and tumor metastasis in vivo. By cytoplasmic and nuclear RNA isolation, LINC00238 was confirmed to be predominantly cytoplasmic. Mechanistically, RNA pull‑down assays showed that LINC00238 sponged microRNA (miR)‑522 and then reversed the inhibitory effects on two downstream targets, secreted frizzled related protein 2 and dickkopf1. Collectively, LINC00238 was identified as a tumor suppressor that acts via sponging miR‑522 followed by silencing of downstream targets, suggesting that LINC00238 may have a key role in suppressing the malignant phenotype of liver cancer cells.

The lncRNA CASC2 Modulates Hepatocellular Carcinoma Cell Sensitivity and Resistance to TRAIL Through Apoptotic and Non-Apoptotic Signaling

The immune cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been widely concerned as a tumor therapy because of its ability of selective triggering cancer cell apoptosis; nevertheless, hepatocellular carcinoma (HCC) exhibits acquired resistance to TRAIL-induced apoptosis. In the present study, tumor-suppressive lncRNA cancer susceptibility candidate 2 (CASC2) was downregulated in HCC tissues and cell lines; HCC patients with lower CASC2 expression predicted a shorter overall survival rate. In vitro, CASC2 overexpression dramatically repressed HCC cell proliferation and inhibited cell apoptosis; in vivo, CASC2 overexpression inhibited subcutaneous xenotransplant tumor growth. CASC2 affected the caspase cascades and NF-κB signaling in TRAIL-sensitive [Huh-7 (S) and HCCLM3 (S)] or TRAIL-resistant cell lines [Huh-7 (R) and HCCLM3 (R)] in different ways. In Huh-7 (S) and HCCLM3 (S) cells, CASC2 affected cell apoptosis through the miR-24/caspase-8 and miR-221/caspase-3 axes and the caspase cascades. miR-18a directly targeted CASC2 and RIPK1. In Huh-7 (R) and HCCLM3 (R) cells, CASC2 affected cell proliferation through the miR-18a/RIPK1 axis and the NF-κB signaling. RELA bound to CASC2 promoter region and inhibited CASC2 transcription. In conclusion, CASC2 affects cell growth mainly via the miR-24/caspase-8 and miR-221/caspase-3 axes in TRAIL-sensitive HCC cells; while in TRAIL-resistant HCC cells, CASC2 affects cell growth mainly via miR-18a/RIPK1 axis and the NF-κB signaling. These outcomes foreboded that CASC2 could be a novel therapeutic target for further study of HCC-related diseases.

Identification of Epithelial Mesenchymal Transition-Related lncRNAs Associated with Prognosis and Tumor Immune Microenvironment of Hepatocellular Carcinoma

Purpose. The long noncoding RNAs (lncRNAs) play the important role in tumor occurrence and progression, and the epithelial to mesenchymal transition (EMT) is the critical process for tumor migration. However, the role of EMT-related lncRNA in hepatocellular carcinoma (HCC) has not been elucidated. Methods. In this study, we selected the EMT-related lncRNAs in HCC by using data from The Cancer Genome Atlas database (TCGA). Two prognostic models of the overall survival (OS) and relapse-free survival (RFS) were constructed and validated through Cox regression model, Kaplan-Meier analysis, and the receiver-operating characteristic (ROC) curves. The unsupervised clustering analysis was utilized to investigate the association between EMT-lncRNAs with tumor immune microenvironment. ESTIMATE algorithm and gene set enrichment analysis (GSEA) were used to estimate tumor microenvironment and associated KEGG pathways. Results. Two EMT-related lncRNA prognostic models of OS and RFS were constructed. Kaplan-Meier curves showed the dismal prognosis of OS and RFS in the group with high-risk score. The ROC curves and AUC values in two prognostic models indicated the discriminative value in the training set and validation set. Patients with HCC were clustered into two subgroups according the unsupervised clustering analysis. Lnc-CCNY-1 was selected as the key lncRNA. GSVA analysis showed that lnc-CCNY-1 was negatively associated with peroxisome proliferator-activated receptor (PPAR) signaling pathway and positively correlated with CELL cycle pathway. Conclusion. Two EMT-related lncRNA prognostic models of OS and RFS were constructed to discriminate patients and predict prognosis of HCC. EMT-related lncRNAs may play a role on prognosis of HCC by influencing the immune microenvironment. Lnc-CCNY-1 was selected as the key EMT-related lncRNA for further exploration.

HIF-1α-activated long non-coding RNA KDM4A-AS1 promotes hepatocellular carcinoma progression via the miR-411-5p/KPNA2/AKT pathway

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with poor clinical outcomes. Long non-coding RNAs (lncRNAs) are extensively involved in the tumorigenesis and progression of HCC. However, more investigations should be carried out on novel lncRNAs and their effects on HCC. Here we identified a novel lncRNA KDM4A-AS1, which was aberrantly overexpressed in HCC tissues, associated with unfavorable clinical features and poor prognosis of patients. KDM4A-AS1 promoted HCC cell proliferation, migration, and invasion in vitro and contributed to HCC growth and lung metastasis in vivo. Mechanistically, KDM4A-AS1 was inversely modulated by miR-411-5p at the post-transcriptional level and facilitated Karyopherin α2 (KPNA2) expression by competitively binding miR-411-5p, thereby activating the AKT pathway. KPNA2 silencing, miR-411-5p overexpression, and AKT inhibitor (MK2206) consistently reversed KDM4A-AS1-enhanced proliferation, mobility, and EMT of HCC cells. KDM4A-AS1 was identified as a novel hypoxia-responsive gene and transactivated by hypoxia-inducible factor 1α (HIF-1α) in HCC cells. In turn, KDM4A-AS1 regulated HIF-1α expression through the KPNA2/AKT signaling pathway. Hence, this study revealed a novel hypoxia-responsive lncRNA, KDM4A-AS1, which contributed to HCC growth and metastasis via the KDM4A-AS1/KPNA2/HIF-1α signaling loop. Our findings provide a promising prognostic and therapeutic target for HCC.

The role of non-coding RNAs in chemotherapy for gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, hepatic, esophageal, and pancreatic tumors, are responsible for large numbers of deaths around the world. Chemotherapy is the most common approach used to treat advanced GI cancer. However, chemoresistance has emerged as a critical challenge that prevents successful tumor elimination, leading to metastasis and recurrence. Chemoresistance mechanisms are complex, and many factors and pathways are involved. Among these factors, non-coding RNAs (ncRNAs) are critical regulators of GI tumor development and subsequently can induce resistance to chemotherapy. This occurs because ncRNAs can target multiple signaling pathways, affect downstream genes, and modulate proliferation, apoptosis, tumor cell migration, and autophagy. ncRNAs can also induce cancer stem cell features and affect the epithelial-mesenchymal transition. Thus, ncRNAs could possibly act as new targets in chemotherapy combinations to treat GI cancer and to predict treatment response.

Emerging role of long noncoding RNAs in recurrent hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most frequent types of liver cancer and is characterized by a high recurrence rate. Recent studies have proposed that long non-coding RNAs (lncRNAs) are potential biomarkers in several recurrent tumor types. It is now well understood that invasion, migration, and metastasis are important factors for tumor recurrence. Moreover, some of the known risk factors for HCC may affect the expression levels of several types of lncRNAs and thus affect the recurrence of liver cancer through lncRNA regulation. In this paper, we review the biological functions, molecular mechanisms, and roles of lncRNAs in HCC and summarize current knowledge about lncRNAs as potential biomarkers in recurrent HCC.

The role of ceRNA-mediated diagnosis and therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide due to its high degree of malignancy, high incidence, and low survival rate. However, the underlying mechanisms of hepatocarcinogenesis remain unclear. Long non coding RNA (lncRNA) has been shown as a novel type of RNA. lncRNA by acting as ceRNA can participate in various biological processes of HCC cells, such as tumor cell proliferation, migration, invasion, apoptosis and drug resistance by regulating downstream target gene expression and cancer-related signaling pathways. Meanwhile, lncRNA can predict the efficacy of treatment strategies for HCC and serve as a potential target for the diagnosis and treatment of HCC. Therefore, lncRNA serving as ceRNA may become a vital candidate biomarker for clinical diagnosis and treatment. In this review, the epidemiology of HCC, including morbidity, mortality, regional distribution, risk factors, and current treatment advances, was briefly discussed, and some biological functions of lncRNA in HCC were summarized with emphasis on the molecular mechanism and clinical application of lncRNA-mediated ceRNA regulatory network in HCC. This paper can contribute to the better understanding of the mechanism of the influence of lncRNA-mediated ceRNA networks (ceRNETs) on HCC and provide directions and strategies for future studies.

LncRNA TMEM220-AS1 suppresses hepatocellular carcinoma cell proliferation and invasion by regulating the TMEM220/β-catenin axis

Long non-coding RNAs (lncRNAs) are critical drivers and suppressors of human hepatocellular carcinoma (HCC). The downregulation of transmembrane protein 220 antisense RNA 1 (TMEM220-AS1) is correlated with poor prognosis in HCC. Nevertheless, the role of TMEM220-AS1 in HCC and the underlying mechanism remains unclear. In this study, TMEM220-AS1 levels were markedly reduced in HCC tissues compared with noncancerous tissues. TMEM220-AS1 downregulation was confirmed in HCC cell lines. TMEM220-AS1 expression was associated with tumor stage, venous infiltration, tumor size, and survival of HCC patients. TMEM220-AS1 overexpression suppressed the migration, invasion, and proliferation of HCC cells. Interestingly, ectopic expression of TMEM220-AS1 increased TMEM220 levels in HCC cells. Decreased TMEM220 levels were observed in HCC tissues and cell lines. TMEM220 expression was positively correlated with TMEM220-AS1 levels in HCC tissue samples and TMEM220 downregulation was significantly correlated with reduced patient survival. TMEM220 overexpression suppressed HCC cell proliferation and mobility. TMEM220 knockdown eliminated the suppressive effect of TMEM220-AS1 in HCCLM3 cells. Mechanistically, TMEM220 overexpression reduced the nuclear accumulation of β-catenin and decreased MYC, Cyclin D1, and Snail1 mRNA levels in HCCLM3 cells. BIO, a GSK3β inhibitor, eliminated TMEM220-induced Wnt/β-catenin pathway inactivation and inhibited HCC cell proliferation and mobility. In conclusion, TMEM220-AS1 and TMEM220 were expressed at low levels in HCC patients. TMEM220-AS1 inhibited the malignant behavior of HCC cells by enhancing TMEM220 expression and subsequently inactivating the Wnt/β-catenin pathway.

Long Non-coding RNA LINC01503 Promotes Gastric Cardia Adenocarcinoma Progression via miR-133a-5p/VIM Axis and EMT Process

BACKGROUND

LINC01503 has been reported to act as a candidate oncogenic lncRNA in several types of human cancer. However, the functions and underlying mechanisms of LINC01503 in gastric cardia adenocarcinoma (GCA) remain unclear.

AIMS

To investigate the roles and underlying mechanisms of LINC01503 in GCA progression.

MATERIALS AND METHODS

Gene expressions were detected by quantitative real-time PCR (qRT-PCR). Gain-of-function assays were performed to evaluate the function of LINC01503 in gastric cancer cells. Bioinformatics analysis, luciferase reporter assay, and RIP assay were performed to identify associations among LINC01503, miR-133a-5p, and VIM.

RESULTS

The expression level of LINC01503 was significantly elevated in GCA tissues and cell lines. High expression of LINC01503 was correlated with lymph node metastasis, TNM stage, and poor prognosis of GCA patients. Knockdown of LINC01503 significantly reduced proliferation, migration, and invasion ability in GC cells. LINC01503 might function as a competing endogenous RNA (ceRNA) via sponging miR-133a-5p to upregulate the expression of VIM. Furthermore, overexpression of LINC01503 promoted the progression of epithelial mesenchymal transition (EMT) in vitro.

CONCLUSION

LINC01503 serves as an oncogenic lncRNA to promote GCA progression via affecting LINC01503/miR-133a-5p/VIM axis and EMT process. LINC01503 not only has a critical role in GCA progression but also provide a novel potential biomarker in predicting prognosis for GCA patients.

Long non-coding RNA TMCC1-AS1 predicts poor prognosis and accelerates epithelial-mesenchymal transition in liver cancer

Long non-coding RNA transmembrane and coiled-coil domain family 1 antisense RNA 1 (TMCC1-AS1) has been frequently reported to be associated with prognosis in patients with liver cancer (LC). However, the biological role of TMCC1-AS1 in LC in vitro remains unclear. The expression levels of TMCC1-AS1 in primary tumor tissues and LC cell lines were determined using reverse transcription-quantitative PCR. The associations between TMCC1-AS1 expression and the clinicopathological factors of patients with LC were statistically analyzed using the χ² test. The role of TMCC1-AS1 in LC prognosis was assessed using Kaplan-Meier curves and proportional hazards model (Cox) analysis. Cell proliferation was determined by Cell Counting Kit-8 and colony formation assays. Transwell assays were performed to determine migration and invasion. TMCC1-AS1 expression was found to be significantly upregulated in LC tissues and cell lines compared with the corresponding controls. High TMCC1-AS1 expression was associated with advanced TNM stage and lymph node metastasis. Furthermore, high TMCC1-AS1 expression predicted poor survival in patients with LC. Knockdown of TMCC1-AS1 significantly inhibited the proliferation, migration and invasion of HepG2 and SNU-182 cells, while overexpression of TMCC1-AS1 had the opposite effect in HepG2 and SNU-182 cells. At the molecular level, downregulation of TMCC1-AS1 expression resulted in increased E-cadherin expression and decreased proliferating cell nuclear antigen, Ki67, N-cadherin and Vimentin expression in HepG2 cells. Overexpression of TMCC1-AS1 had the opposite effects on these factors in SNU-182 cells. In conclusion, the present findings indicated that TMCC1-AS1 might be considered as a novel oncogene, which promotes cell proliferation and migration, and may be a potential therapeutic target for LC.

The Role of Long Non-Coding RNA and microRNA Networks in Hepatocellular Carcinoma and Its Tumor Microenvironment

Hepatocellular carcinoma (HCC) is a common liver malignancy with high morbidity and poor prognosis. Long non-coding RNAs (lncRNAs) are involved in crucial biological processes of tumorigenesis and progression, and play four major regulatory roles, namely signal, decoy, guide, and scaffold, to regulate gene expression. Through these processes, lncRNAs can target microRNAs (miRNAs) to form lncRNA and miRNA networks, which regulate cancer cell proliferation, metastasis, drug resistance, and the tumor microenvironment. Here, we summarize the multifaceted functions of lncRNA and miRNA networks in the pathogenesis of HCC, the potential use of diagnostic or prognostic biomarkers, and novel therapeutic targets in HCC. This review also highlights the regulatory effects of lncRNA and miRNA networks in the tumor microenvironment of HCC.

Tumor Mutation Burden-Associated LINC00638/miR-4732-3p/ULBP1 Axis Promotes Immune Escape via PD-L1 in Hepatocellular Carcinoma

Tumor mutation burden (TMB) is associated with immune infiltration, while its underlying mechanism in hepatocellular carcinoma (HCC) remains unclear. A long noncoding RNA (lncRNA)-related competitive endogenous RNA (ceRNA) network can regulate various tumor behaviors, and research about its correlation with TMB and immune infiltration is warranted. Data were downloaded from TCGA and ArrayExpress databases. Cox analysis and machine learning algorithms were employed to establish a lncRNA-based prognostic model for HCC. We then developed a nomogram model to predict overall survival and odds of death for HCC patients. The association of this prognostic model with TMB and immune infiltration was also analyzed. In addition, a ceRNA network was constructed by using DIANA-LncBasev2 and the starBase database and verified by luciferase reporter and colocalization analysis. Multiplex immunofluorescence was applied to determine the correlation between ULBP1 and PD-L1. An eight-lncRNA (SLC25A30-AS1, HPN-AS1, LINC00607, USP2-AS1, HCG20, LINC00638, MKLN1-AS and LINC00652) prognostic score model was constructed for HCC, which was highly associated with TMB and immune infiltration. Next, we constructed a ceRNA network, LINC00638/miR-4732-3p/ULBP1, that may be responsible for NK cell infiltration in HCC with high TMB. However, patients with high ULBP1 possessed a poorer prognosis. Using multiplex immunofluorescence, we found a significant correlation between ULBP1 and PD-L1 in HCC, and patients with high ULBP1 and PD-L1 had the worst prognosis. In brief, the eight-lncRNA model is a reliable tool to predict the prognosis of HCC patients. The LINC00638/miR-4732-3p/ULBP1 axis may regulate immune escape via PD-L1 in HCC with high TMB.

Implications of FBXW7 in Neurodevelopment and Neurodegeneration: Molecular Mechanisms and Therapeutic Potential

The ubiquitin-proteasome system (UPS) mediated protein degradation is crucial to maintain quantitive and functional homeostasis of diverse proteins. Balanced cellular protein homeostasis controlled by UPS is fundamental to normal neurological functions while impairment of UPS can also lead to some neurodevelopmental and neurodegenerative disorders. Functioning as the substrate recognition component of the SCF-type E3 ubiquitin ligase, FBXW7 is essential to multiple aspects of cellular processes via targeting a wide range of substrates for proteasome-mediated degradation. Accumulated evidence shows that FBXW7 is fundamental to neurological functions and especially implicated in neurodevelopment and the nosogenesis of neurodegeneration. In this review, we describe general features of FBXW7 gene and proteins, and mainly present recent findings that highlight the vital roles and molecular mechanisms of FBXW7 in neurodevelopment such as neurogenesis, myelination and cerebral vasculogenesis and in the pathogenesis of some typical neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and Huntington’s disease. Additionally, we also provide a prospect on focusing FBXW7 as a potential therapeutic target to rescue neurodevelopmental and neurodegenerative impairment.

Emerging roles of a pivotal lncRNA SBF2-AS1 in cancers

Long non-coding RNAs refer to transcripts over 200 nt in length that lack the ability to encode proteins, which occupy the majority of the genome and play a crucial role in the occurrence and development of human diseases, especially cancers. SBF2-AS1, a newly identified long non-coding RNA, has been verified to be highly expressed in diversiform cancers, and is involved in processes promoting tumorigenesis, tumor progression and tumor metastasis. Moreover, upregulation of SBF2-AS1 expression was significantly related to disadvantageous clinicopathologic characteristics and indicated poor prognosis. In this review, we comprehensively summarize the up-to-date knowledge of the detailed mechanisms and underlying functions of SBF2-AS1 in diverse cancer types, highlighting the potential of SBF2-AS1 as a diagnostic and prognostic biomarker and even a therapeutic target.

LncRNA CASC2 is involved in the development of chronic obstructive pulmonary disease via targeting miR-18a-5p/IGF1 axis

AIMS

Chronic obstructive pulmonary disease (COPD) is a systemic disease. Several long non-coding RNAs (lncRNAs) have been identified to be aberrantly expressed in COPD patients. This study investigated the role of lncRNA cancer susceptibility candidate 2 (CASC2) in COPD, as well as its potential mechanism.

METHODS

Fifty smokers with COPD and another 50 smokers without COPD were recruited. Receiver operating characteristic curve was constructed to assess the diagnostic value of CASC2 in COPD patients. 16HBE cells were treated with cigarette smoke extract (CSE) to establish a cell model. qRT-PCR was used for the measurement of mRNA levels. The cell viability and apoptosis were detected by using Cell Counting Kit-8 and flow cytometry assay. Enzyme-linked immunosorbent assay was performed to detect the levels of proinflammatory cytokines. Luciferase reporter assay was performed for the target gene analysis.

RESULTS

Serum CASC2 was dramatically decreased in COPD patients compared with smokers without COPD, and was positively associated with FEV1 (forced expiratory volume in one second). Serum CASC2 was overexpressed in severe COPD patients, and had the diagnostic accuracy to distinguish COPD patients from smokers. CASC2 overexpression alleviated CSE-induced apoptosis and inflammation in 16HBE cells. CASC2 functions as a ceRNA of miR-18a-5p. Upregulation of miR-18a-5p reversed the influence of CASC2 on cell apoptosis and inflammation in 16HBE cells. IGF1 was the target gene of miR-18a-5p.

CONCLUSION

CASC2 was downregulated in COPD patients and it might be a promising biomarker for the disease diagnosis. Overexpression of CASC2 might inhibit the bronchial epithelial cell apoptosis and inflammation via targeting miR-18a-5p/IGF1 axis.The reviews of this paper are available via the supplemental material section.

F-box proteins in cancer stemness: An emerging prognostic and therapeutic target

Cancer is a complex heterogenic disease with significant therapeutic challenges. The presence of cancer stem cells (CSCs) in cancer tissue orchestrates tumor growth, progression, and metastasis, the tumor heterogeneity, disease relapse, and therapeutic resistance. Hence, it is imperative to explore how progenitor or cancer-initiating cells acquire stemness features and reprogram different biological mechanisms to maintain their sustained oncogenicity. Interestingly, deregulation of F-box proteins (FBPs) is crucial for cancer stemness features, including drug resistance and disease relapse. In this review, we highlight recent updates on the clinical significance of targeting FBPs in cancer therapy, with emphasis on eliminating CSCs and associated therapeutic challenges. Moreover, we also discuss novel strategies for the selective elimination of CSCs by targeting FBPs.

LncRNA HCP5 promotes malignant cell behaviors in esophageal squamous cell carcinoma via the PI3K/AKT/mTOR signaling

The role of lncRNA HCP5 in esophageal squamous cell carcinoma (ESCC) remains unknown despite its involvement in different malignancies. MTT assay, EdU assay, TUNEL assay, transwell assay, and sphere formation assay were conducted to reveal ESCC cell viability, proliferation, apoptosis, migration, invasion, and stemness characteristics. FISH and subcellular fraction assays were performed to reveal the subcellular location of HCP5 in ESCC cells. Luciferase reporter assay and RIP assay were conducted to explore the downstream axis of HCP5. Our findings revealed that HCP5 expression was at a higher level in ESCC tissues and cells compared to that in control tissues and cells. Additionally, HCP5 promoted ESCC cellular activities by promoting proliferation, migration, invasion ability and stemness characteristics of ESCC cells as well as suppressing cell apoptosis. Furthermore, we found that HCP5 bound with miR-139-5p to upregulate PDE4A via the competing endogenous RNA network in ESCC cells. Importantly, HCP5 was discovered to stimulate the PI3K/AKT/mTOR signaling by regulating the downstream target genes. Finally, rescue assays indicated that HCP5 promoted ESCC cell growth by activating the PDE4A-medaited PI3K/AKT/mTOR pathway. HCP5 promotes ESCC cellular development by modulating the miR-139-5p/PDE4A pathway and stimulating the PI3K/AKT/mTOR signaling pathway, which may be conducive for the improvement of ESCC treatment.

The Landscape of lncRNAs in Hepatocellular Carcinoma: A Translational Perspective

LncRNAs are emerging as relevant regulators of multiple cellular processes involved in cell physiology as well as in the development and progression of human diseases, most notably, cancer. Hepatocellular carcinoma (HCC) is a prominent cause of cancer-related death worldwide due to the high prevalence of causative factors, usual cirrhotic status of the tumor-harboring livers and the suboptimal benefit of locoregional and systemic therapies. Despite huge progress in the molecular characterization of HCC, no oncogenic loop addiction has been identified and most genetic alterations remain non-druggable, underscoring the importance of advancing research in novel approaches for HCC treatment. In this context, long non-coding RNAs (lncRNAs) appear as potentially useful targets as they often exhibit high tumor- and tissue-specific expression and many studies have reported an outstanding dysregulation of lncRNAs in HCC. However, there is a limited perspective of the potential role that deregulated lncRNAs may play in HCC progression and aggressiveness or the mechanisms and therapeutic implications behind such effects. In this review, we offer a clarifying landscape of current efforts to evaluate lncRNA potential as therapeutic targets in HCC using evidence from preclinical models as well as from recent studies on novel oncogenic pathways that show lncRNA-dependency.