The long non-coding RNA AK023948 enhances tumor progression in hepatocellular carcinoma

Non-coding RNA mediated regulation of PI3K/Akt pathway in hepatocellular carcinoma: Therapeutic perspectives

Hepatocellular carcinoma (HCC) is among the primary reasons for fatalities caused by cancer globally, highlighting the need for comprehensive knowledge of its molecular aetiology to develop successful treatment approaches. The PI3K/Akt system is essential in the course of HCC, rendering it an intriguing candidate for treatment. Non-coding RNAs (ncRNAs), such as long ncRNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are important mediators of the PI3K/Akt network in HCC. The article delves into the complex regulatory functions of ncRNAs in influencing the PI3K/Akt system in HCC. The study explores how lncRNAs, miRNAs, and circRNAs impact the expression as well as the function of the PI3K/Akt network, either supporting or preventing HCC growth. Additionally, treatment strategies focusing on ncRNAs in HCC are examined, such as antisense oligonucleotide-based methods, RNA interference, and small molecule inhibitor technologies. Emphasizing the necessity of ensuring safety and effectiveness in clinical settings, limitations, and future approaches in using ncRNAs as therapies for HCC are underlined. The present study offers useful insights into the complex regulation system of ncRNAs and the PI3K/Akt cascade in HCC, suggesting possible opportunities for developing innovative treatment approaches to address this lethal tumor.

LINC00478-derived novel cytoplasmic lncRNA LacRNA stabilizes PHB2 and suppresses breast cancer metastasis via repressing MYC targets

BACKGROUND

Metastasis is the predominant cause of mortality in patients with breast cancer. Long noncoding RNAs (lncRNAs) have been shown to drive important phenotypes in tumors, including invasion and metastasis. However, the lncRNAs involved in metastasis and their molecular and cellular mechanisms are still largely unknown.

METHODS

The transcriptional and posttranscriptional processing of LINC00478-associated cytoplasmic RNA (LacRNA) was determined by RT-qPCR, semiquantitative PCR and 5'/3' RACE. Paired-guide CRISPR/cas9 and CRISPR/dead-Cas9 systems was used to knock out or activate the expression of LacRNA. Cell migration and invasion assay was performed to confirm the phenotype of LacRNA. Tail vein model and mammary fat pad model were used for in vivo study. The LacRNA-PHB2-cMyc axis were screened and validated by RNA pulldown, mass spectrometry, RNA immunoprecipitation and RNA-seq assays.

RESULTS

Here, we identified a novel cytoplasmic lncRNA, LacRNA (LINC00478-associated cytoplasmic RNA), derived from nucleus-located lncRNA LINC00478. The nascent transcript of LINC00478 full-length (LINC00478_FL) was cleaved and polyadenylated, simultaneously yielding 5' ends stable expressing LacRNA, which is released into the cytoplasm, and long 3' ends of nuclear-retained lncRNA. LINC00478_3'RNA was rapidly degraded. LacRNA significantly inhibited breast cancer invasion and metastasis in vitro and in vivo. Mechanistically, LacRNA physically interacted with the PHB domain of PHB2 through its 61-140-nt region. This specific binding affected the formation of the autophagy degradation complex of PHB2 and LC3, delaying the degradation of the PHB2 protein. Unexpectedly, LacRNA specifically interacted with PHB2, recruited c-Myc and promoted c-Myc ubiquitination and degradation. The negatively regulation of Myc signaling ultimately inhibited breast cancer metastasis. Furthermore, LacRNA and LacRNA-mediated c-Myc signaling downregulation are significantly associated with good clinical outcomes, take advantage of these factors we constructed a prognostic predict model.

CONCLUSION

Therefore, our findings propose LacRNA as a potential prognostic biomarker and a new therapeutic strategy.

Epigenetic Regulation of Hepatocellular Carcinoma Progression through the mTOR Signaling Pathway

Hepatocellular carcinoma (HCC), the most common type of primary liver cancer, is an aggressive tumor with a high mortality rate because of the limited systemic and locoregional treatment modalities. The development and progression of HCC depend on epigenetic changes that result in the activation or inhibition of some signaling pathways. The mTOR signaling pathway is essential for many pathophysiological processes and is considered a major regulator of cancer. Increasing evidence has shown that epigenetics plays a key role in HCC biology by regulating the mTOR signaling pathway. Therefore, epigenetic regulation through the mTOR signaling pathway to diagnose and treat HCC will become a very promising strategy.

LINC00221 silencing prevents the progression of hepatocellular carcinoma through let-7a-5p-targeted inhibition of MMP11

Background

Microarray profiles of hepatocellular carcinoma (HCC) identified that long intergenic noncoding RNA 00221 (LINC00221) was upregulated. Herein, we aimed to identify the functional significance and underlying mechanisms of LINC00221 in HCC.

Methods and results

Human HCC samples had increased expression of LINC00221. Effects of LINC00221 on HCC cellular functions were analyzed using gain- and loss-function approaches. LINC00221 knockdown repressed HCC cell growth, migration, and invasion and enhanced their apoptosis. This anti-tumor effect was validated in vivo. Online prediction showed the potential binding relationship between LINC00221 and let-7a-5p, as well as that between let-7a-5p and matrix metalloproteinase 11 (MMP11). The results of luciferase, RNA immunoprecipitation, and RNA pull-down assays identified that LINC00221 interacted with let-7a-5p to increase expression of MMP11. Furthermore, we demonstrated that LINC00221 silencing increased let-7a-5p and inhibited MMP11 expression, thereby delaying the progression of HCC in vitro.

Conclusions

Silencing of LINC00221 could prevent HCC progression via upregulating let-7a-5p and downregulating MMP11. As such, LINC00221 inhibition presents a promising antitumor strategy for the treatment of HCC.

Long noncoding RNA PTCSC1 drives esophageal squamous cell carcinoma progression through activating Akt signaling

Long noncoding RNAs (lncRNAs) have critical roles in various malignancies. However, the specific expression and roles of lncRNA PTCSC1 in esophageal squamous cell carcinoma (ESCC) are still unknown. Here, we identified that lncRNA PTCSC1 was elevated in ESCC tissues and cell lines compared with adjacent noncancerous tissues and normal esophageal epithelial cell line, respectively. Enhanced expression of PTCSC1 facilitated ESCC cells proliferation and migration in vitro and ESCC xenograft growth in vivo. Conversely, deficiency of PTCSC1 suppressed ESCC cells proliferation and migration in vitro and ESCC tumor growth in vivo. Furthermore, PTCSC1 was found to activate Akt signaling in ESCC cells. Blocking Akt signaling with MK-2206 abolished the pro-proliferative and pro-migratory roles of PTCSC1. In summary, our findings demonstrated PTCSC1 as an oncogenic lncRNA in ESCC via activating Akt signaling and suggested that targeting PTCSC1 represents a promising therapeutic strategy against ESCC.

PI3K/AKT/mTOR pathway-related long non-coding RNAs: roles and mechanisms in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide with high prevalence and lethality. The oncogenic phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a classic dysregulated pathway involved in the pathogenesis of HCC. However, the underlying mechanism for how PI3K/AKT/mTOR pathway aberrantly activates HCC has not been entirely elucidated. The recognition of the functional roles of long non-coding RNAs (lncRNAs) in PI3K/AKT/mTOR signaling axis sheds light on a new dimension to our understanding of hepatocarcinogenesis. In this review, we comprehensively summarize 67 dysregulated PI3K/AKT/mTOR pathway-related lncRNAs in HCC. Many studies have indicated that the 67 dysregulated lncRNAs show oncogenic or anti-oncogenic effects in HCC by regulation on epigenetic, transcriptional and post-transcriptional levels and they play pivotal roles in the initiation of HCC in diverse biological processes like proliferation, metastasis, drug resistance, radio-resistance, energy metabolism, autophagy and so on. Besides, many of these lncRNAs are associated with clinicopathological features and clinical prognosis in HCC, which may provide a potential future application in the diagnosis and therapy of HCC.

SEMA3F Promotes Liver Hepatocellular Carcinoma Metastasis by Activating Focal Adhesion Pathway

Previous studies have shown that semaphorin-3F (SEMA3F) functions as a tumor suppressor in several tumor types. However, the role of SEMA3F in the metastasis and prognosis of liver hepatocellular carcinoma (LIHC) remains unknown. In this study, by performing bioinformatics analysis on the transcriptome profiles from The Cancer Genome Atlas (TCGA), we demonstrated that SEMA3F was significantly upregulated in LIHC tissues, compared with normal controls. Moreover, the expression value of SEMA3F was positively correlated with patients' pathological stages and tumor metastasis, predicting a poor overall survival. Besides, SEMA3F expression level was negatively correlated with its methylation level, but positively correlated with its gene copy number. Differential expression analysis of LIHC samples with high or low SEMA3F expression values suggested that 983 genes were differentially expressed, among which 723 genes were upregulated and 260 genes were downregulated. Furthermore, enrichment analysis of differentially expressed genes revealed that SEMA3F was involved in the activation of focal adhesion pathway, which induced tumor metastasis. Taken together, our results suggested that the oncogenic function of SEMA3F promoted hepatocellular carcinoma metastasis by activating focal adhesion pathway.

Long noncoding RNA MAFG-AS1 promotes proliferation, migration and invasion of hepatocellular carcinoma cells through downregulation of miR-6852

Long noncoding RNAs (lncRNAs) have been shown to participate in the development and progression of a number of different types of cancer, including hepatocellular carcinoma (HCC). A recent report has indicated that lncRNA MAFG-antisense 1 (AS1) promotes colorectal cancer. However, the role of MAFG-AS1 in other types of cancer remains unclear. The aim of the present study was to examine the effect of lncRNA MAFG-AS1 in HCC. Based on The Cancer Genome Atlas database and reverse transcription-quantitative PCR results, it was determined that lncRNA MAFG-AS1 expression was increased in HCC tissues and cell lines. Following knockdown of lncRNA MAFG-AS1, a Cell Counting Kit-8 assay and Transwell assay demonstrated that the proliferation, migration and invasion of HCC cell lines were significantly inhibited. It was additionally demonstrated that there was a negative regulatory association between lncRNA MAFG-AS1 and miR-6852. Inhibition of miR-6852 increased proliferation, migration and invasion of HCC cell lines. LncRNA MAFG-AS1 promoted HCC development by dampening miR-6852 function and may thus be a novel target for treating patients with HCC.

The lncRNA ZEB2-AS1 is upregulated in gastric cancer and affects cell proliferation and invasion via miR-143-5p/HIF-1α axis

Background

Growing evidence has implicated the important role of the long non-coding RNAs (lncRNAs) in gastric cancer progression. In this study, we examined the expression of lncRNA zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) in gastric cancer tissues and elucidated the molecular mechanisms underlying ZEB2-AS1-mediated gastric cancer progression.

Methods

Quantitative real-time PCR measured the gene expression level; CCK-8, colony formation and cell invasion assays determined gastric cancer cell proliferation, growth and invasion, respectively; the xenograft nude mice model was used to determine in vivo tumor growth; Bioinformatics analysis and luciferase reporter assay determined the downstream targets of ZEB2-AS1 and miR-143-5p. The expression of ZEB2-AS1 was upregulated in gastric cancer cell lines.

Results

Knockdown of ZEB2-AS1 suppressed gastric cancer cell proliferation, growth and invasion, and also suppressed in vivo tumor growth in the nude mice. Overexpression of ZEB2-AS1 potentiated gastric cancer cell proliferation, growth and invasion. Bioinformatics analysis and luciferase reporter assay showed that miR-143-5p was a direct target of ZEB2-AS1 and was negatively regulated by ZEB2-AS1. Furthermore, hypoxia-inducible factor-1α (HIF-1α) was found to be a target of miR-143-5p and was negatively regulated by miR-143-5p. The rescue in vitro assays showed that the effects of ZEB2-AS1 overexpression on gastric cancer cell proliferation, growth and invasion was mediated via miR-143-5p/HIF-1α. ZEB2-AS1 and HIF-1α was upregulated in gastric cancer tissues, while miR-143-5p was down-regulated; and ZEB2-AS1 expression level was inversely correlated with miR-143-5p expression level, and positively correlated with HIF-1α mRNA expression level; while miR-143-5p expression level was inversely correlated with HIF-1α expression level. High ZEB2-AS1 expression level was correlated with poor differentiation, lymph node metastasis and distant metastasis.

Conclusion

Collectively, our results indicated that ZEB2-AS1 was up-regulated in gastric cancer tissues and cells and promoted cell proliferation and metastasis through miR-143-5p/HIF-1α pathway, which may provide a promising target for treatment of gastric cancer.

Downregulation of lncRNA OGFRP1 inhibits hepatocellular carcinoma progression by AKT/mTOR and Wnt/β-catenin signaling pathways

Introduction

Increasing evidence demonstrates that long noncoding RNAs (lncRNAs) play important roles in the progression of hepatocellular carcinoma (HCC) by regulating gene expression. However, the identification of functional lncRNAs in HCC remains insufficient. Our study aimed to investigate the function of lncRNA OGFRP1, which has not been functionally researched before, in Hep3B and HepG2 cells.

Methods

lncRNA OGFRP1 in HCC cells was down-regulated by using RNAi technology. Quantitative real-time polymerase chain reaction was used to determine the mRNA expression of lncRNA OGFRP1. Cell proliferation was examined by CCK8 and clone formation assays. Cell cycle and apoptosis were analyzed by flow cytometry. Cell migration and invasion were assessed by using Scratch assay and transwell assay, respectively. Protein expression of signaling pathways was determined by using Western blot.

Results

Cell proliferation of Hep3B was significantly inhibited by down-regulation of lncRNA OGFRP1 (P<0.05). Moreover, siOGFRP1 transfection induced Hep3B cell cycle arrest and apoptosis by regulating the expression of related proteins. Cell migration and invasion of Hep3B were also significantly inhibited by down-regulation of lncRNA OGFRP1. Wnt/β-catenin signaling pathway, involved in epithelial–mesenchymal transition (EMT), was inactivated by lncRNA OGFRP1 downregulation, including decreased expression of Wnt3a, β-catenin, N-cadherin and vimentin and increased expression of E-cadherin. We also found that the inhibitory effect of lncRNA OGFRP1 knockdown on Hep3B was mediated by the AKT/mTOR signaling pathway and IGF-1, an AKT signaling activator, could rescue the cellular phenotype. However, knockdown of lncRNA OGFRP1 did not influence cell proliferation, migration and invasion in HepG2 cells.

Conclusion

We found that downregulation of lncRNA OGFRP1 suppressed the proliferation and EMT of HCC Hep3B cells through AKT and Wnt/β-catenin signaling pathways. However, lncRNA OGFRP1 exhibited a differentiated function in different HCC cell lines, which required further study in the future.