Long noncoding RNA network: Novel insight into hepatocellular carcinoma metastasis (Review)

Macrophage polarization in hepatocellular carcinoma: a lncRNA-centric perspective on tumor progression and metastasis

Hepatocellular carcinoma (HCC) represents a multifaceted and aggressive cancer frequently associated with chronic inflammation and immune cell activation. The pathogenesis of HCC is influenced by a variety of factors such as long non-coding RNAs (lncRNAs). LncRNAs, a significant class of non-coding RNAs, contribute to the intricate nature of the transcriptome and are extensively distributed across various tissues and cell types in mammals. In HCC, these transcripts are crucial not only for deepening our molecular understanding but also for advancing clinical outcomes, as they serve as both oncogenes and tumor suppressors by dysregulating essential genes and signaling pathways. Additionally, macrophage polarization is crucial in HCC tumor progression. The study explores the role of lncRNAs in hepatocellular carcinoma (HCC) and elucidates the specific molecular mechanisms by which key lncRNAs such as HULC and MALAT1 regulate macrophage polarization in the tumor microenvironment. These lncRNAs modulate cytokine profiles and influence immune regulators including IL-10 and TGF-β, steering macrophages toward an M2-like, pro-tumor phenotype that fosters aggressive tumor characteristics and progression. Mechanistically, these transcripts interact with epigenetic modifiers like EZH2 to alter histone modifications and chromatin accessibility, while also stabilizing mRNAs that encode inflammatory mediators, thereby reinforcing an immunosuppressive response. The clinical implications of these findings are substantial. The detection of such lncRNAs in patient samples offers a minimally invasive diagnostic avenue, while their pivotal role in complex immune cell behavior positions them as promising prognostic biomarkers. Moreover, targeting these lncRNAs may lead to innovative therapeutic strategies aimed at disrupting tumor-supportive inflammatory cascades and restoring an effective antitumor immune response. Understanding the intricate interplay between lncRNA-mediated epigenetic regulation and macrophage polarization not only refines our grasp of HCC progression but also opens new pathways for interventions designed to improve patient outcomes.

MiR-518b Promotes the Tumorigenesis of Hepatocellular Carcinoma by Targeting EGR1 to Regulate PI3K/AKT/mTOR Signaling Pathway

Hepatocellular carcinoma (HCC) is a prevalent malignancy originating from hepatocytes and is characterized by high invasiveness and fatality. Dysregulation of microRNAs (miRNAs) is frequently observed during HCC progression. This study aimed to investigate the role of miR-518b in HCC cell malignancy and tumor growth. MiR-518b expression in HCC cells was measured by RT-qPCR. The proliferative, migratory and invasive capabilities of Hep3B and SNU-387 were assessed by colony formation, wound healing and transwell assays, respectively. RNA immunoprecipitation and luciferase reporter assays were utilized to verify the binding between miR-518b and its target gene, early growth response factor 1 (EGR1). Results revealed that miR-518b was highly expressed while EGR1 was downregulated in HCC cells. Knockdown of miR-518b significantly repressed cell proliferation, migration and invasion. Moreover, miR-518b bound to 3'untranslated region of EGR1 and negatively regulated its expression in HCC cells. EGR1 knockdown counteracted the inhibitory impact of miR-518b inhibition on malignant cell behaviors. In addition, the silencing of EGR1 activated the PI3K/AKT/mTOR signaling in HCC cells, while miR-518b depletion had the opposite effect. Importantly, the suppressive impact of miR-518b on the pathway was rescued by EGR1 knockdown. In vivo experiments demonstrated that inhibition of miR-518b suppressed HCC tumor growth, reduced EGR1 and Ki67 (a proliferation marker) expression, and inactivated the PI3K/AKT/mTOR signaling. In conclusion, miR-518b promotes HCC tumorigenesis by targeting EGR1 and regulating the PI3K/AKT/mTOR signaling pathway.

A negative feedback loop between KLF9 and the EMT program dictates metastasis of hepatocellular carcinoma

Metastasis is the primary cause of death of hepatocellular carcinoma (HCC), while the mechanism underlying this severe disease remains largely unclear. The Kruppel-like factor (KLF) family is one of the largest transcription factor families that control multiple physiologic and pathologic processes by governing the cellular transcriptome. To identify metastatic regulators of HCC, we conducted gene expression profiling on the MHCC97 cell series, a set of subclones of the original MHCC97 that was established by in vivo metastasis selection therefore harbouring differential metastatic capacities. We found that the expression of KLF9, a member of the KLF family, was dramatically repressed in the metastatic progeny clone of the MHCC97 cells. Functional studies revealed overexpression of KLF9 suppressed HCC migration in vitro and metastasis in vivo, while knockdown of KLF9 was sufficient to promote cell migration and metastasis accordingly. Mechanistically, we found the expression of KLF9 can reverse the pro-metastatic epithelial-mesenchymal transition (EMT) program via direct binding to the promoter regions of essential mesenchymal genes, thus repressing their expression. Interestingly, we further revealed that KLF9 was, in turn, directly suppressed by a mesenchymal transcription factor Slug, suggesting an intriguing negative feedback loop between KLF9 and the EMT program. Using clinical samples, we found that KLF9 was not only downregulated in HCC tissue compared to its normal counterparts but also further reduced in the HCC samples of whom had developed metastatic lesions. Together, we established a critical transcription factor that represses HCC metastasis, which is clinically and mechanically significant in HCC therapies.

Role of lncRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is among the deadliest cancer in human malignancies. It is the most common and severe type of primary liver cancer. However, the molecular mechanisms underlying HCC pathogenesis remain poorly understood. Long non-coding RNAs (lncRNAs), a new kind of RNA and epigenetic factors, play a crucial role in tumorigenesis and the progression of HCC. LncRNAs are capable of promoting the autophagy, proliferation, and migration of tumor cells by targeting and modulating the expression of downstream genes in signaling pathways related to cancer; these transcripts modify the activity and expression of various tumor suppressors and oncogenes. LncRNAs could act as biomarkers for treatment approaches such as immunotherapy, chemotherapy, and surgery to effectively treat HCC patients. Improved knowledge regarding the aetiology of HCC may result from an advanced understanding of lncRNAs. Enhanced oxidative stress in the mitochondrial and Endoplasmic reticulum leads to the activation of unfolded protein response pathway that plays a crucial role in the pathophysiology of hepatocellular carcinoma. The mutual regulation between LncRNAs and Endoplasmic reticulum (ER) stress in cancer and simultaneous activation of the unfolded protein response (UPR) pathway determines the fate of tumor cells in HCC. Mitochondria-associated lncRNAs work as essential components of several gene regulatory networks; abnormal regulation of mitochondria-associated lncRNAs may lead to oncogenesis, which provides further insight into the understanding of tumorigenesis and therapeutic strategies.

LncRNA THAP9-AS1 highly expressed in tissues of hepatocellular carcinoma and accelerates tumor cell proliferation

BACKGROUND

Long noncoding RNAs (lncRNAs) are emerging as significant regulators of cancer development. The purposes of study were to analyze the expression levels of long noncoding RNA THAP9-AS1 (THAP9-AS1) in hepatocellular carcinoma (HCC) tissue samples and cell lines, evaluate the clinical significance of THAP9-AS1 in predicting the survival prognosis of HCC patients, and explore the biological function of THAP9-AS1 in regulating tumor progression of HCC.

METHODS

The expression of THAP9-AS1 was determined by quantitative real-time PCR. The determination of HCC cell proliferation was performed using cell counting kit-8 assay. Chi-square test was used to reveal the relationship between THAP9-AS1 and clinicopathological data of HCC patients. Kaplan-Meier method, log-rank test were used to perform analyze the relationship between THAP9-AS1 and prognostic survival in HCC patients. Cox regression was used to evaluate the abilities of THAP9-AS1 to predict survival outcomes in HCC patients.

RESULTS

The expression of THAP9-AS1 were markedly upregulated in HCC tissue and cells. THAP9-AS1 expression was correlated with tumor size, tumor node metastasis (TNM) stage. High THAP9-AS1 expression was associated with poor prognostic survival in HCC patients. THAP9-AS1 was an independent prognostic factor for HCC patients. Overexpression of THAP9-AS1 promoted HCC cell proliferation, silencing THAP9-AS1 inhibited HCC cell proliferation.

CONCLUSION

Aberrantly highly expressed THAP9-AS1 in HCC tissues and cells was associated with tumor size, TNM stage and poor survival prognosis, and promoted HCC cell proliferation. THAP9-AS1 had the potential to serve as independent prognostic biomarker for HCC patients and provide a novel target for HCC patients' prognostic treatment.

LINC00665 regulates hepatocellular carcinoma by modulating mRNA via the m6A enzyme

This study aimed to reveal the mechanism by which long noncoding RNAs (lncRNAs) modulate hepatocellular carcinoma (HCC) by regulating mRNA via the N6-methyladenosine (m6A) enzyme. The expression and clinical data of 365 HCC patients and 50 healthy control samples were downloaded from the the Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs (DElncRNAs) and differentially expressed mRNAs (DEmRNAs) screened using limma packages from the R. m6A2Target database were used to predict the relationship between m6A enzyme-lncRNA and m6A enzyme-mRNA. The mRNAs in the lncRNA-m6A enzyme-mRNA network were subjected to enrichment analysis. Cox regression analysis was used to screen for RNAs significantly related to HCC prognosis. The expression of differentially expressed RNAs (DERs) was verified using the TCGA dataset and GSE55092. Eighty-five DElncRNAs and 747 DEmRNAs were identified. The mRNAs in the lncRNA-m6A enzyme-mRNA network were primarily involved in mitotic cell division, the p53 signaling pathway, and the cell cycle. Three lncRNAs and 14 mRNAs were significantly associated with HCC prognosis. Furthermore, the expression of 12 DERs differed significantly between patients in the early and advanced stages. LINC00665 was predicted to regulate 11 mRNAs by modulating IGF2BP1, IGF2BP2, and YTHDF1. Thus, this study provides new insights into the roles of lncRNA and m6A enzymes in HCC.

Modulating microRNAs in cancer: Next-generation therapies

MicroRNAs (miRNAs) are a class of endogenously expressed non-coding regulators of the genome with an ability to mediate a variety of biological and pathological processes. There is growing evidence demonstrating frequent dysregulation of microRNAs in cancer cells, which is associated with tumor initiation, development, migration, invasion, resisting cell death, and drug resistance. Studies have shown that modulation of these small RNAs is a novel and promising therapeutic tool in the treatment of a variety of diseases, especially cancer, due to their broad influence on multiple cellular processes. However, suboptimal delivery of the appropriate miRNA to the cancer sites, quick degradation by nucleases in the blood circulation, and off target effects have limited their research and clinical applications. Therefore, there is a pressing need to improve the therapeutic efficacy of miRNA modulators, while at the same time reducing their toxicities. Several delivery vehicles for miRNA modulators have been shown to be effective in vitro and in vivo. In this review, we will discuss the role and importance of miRNAs in cancer and provide perspectives on currently available carriers for miRNA modulation. We will also summarize the challenges and prospects for the clinical translation of miRNA-based therapeutic strategies.

Mechanisms of Long Non-Coding RNAs in Biological Characteristics and Aerobic Glycolysis of Glioma

Glioma is the most common and aggressive tumor of the central nervous system. The uncontrolled proliferation, cellular heterogeneity, and diffusive capacity of glioma cells contribute to a very poor prognosis of patients with high grade glioma. Compared to normal cells, cancer cells exhibit a higher rate of glucose uptake, which is accompanied with the metabolic switch from oxidative phosphorylation to aerobic glycolysis. The metabolic reprogramming of cancer cell supports excessive cell proliferation, which are frequently mediated by the activation of oncogenes or the perturbations of tumor suppressor genes. Recently, a growing body of evidence has started to reveal that long noncoding RNAs (lncRNAs) are implicated in a wide spectrum of biological processes in glioma, including malignant phenotypes and aerobic glycolysis. However, the mechanisms of diverse lncRNAs in the initiation and progression of gliomas remain to be fully unveiled. In this review, we summarized the diverse roles of lncRNAs in shaping the biological features and aerobic glycolysis of glioma. The thorough understanding of lncRNAs in glioma biology provides opportunities for developing diagnostic biomarkers and novel therapeutic strategies targeting gliomas.

Role of the Inflammatory Response of RAW 264.7 Cells in the Metastasis of Novel Cancer Stem-Like Cells

Background and objectives: Tumor progression and the immune response are intricately linked. Additionally, the presence of macrophages in the microenvironment is essential for carcinogenesis, but regulation of the polarization of M1- and M2-like macrophages and their role in metastasis remain unclear. Based on previous studies, both reactive oxygen species (ROS) and the endoplasmic reticulum (ER) are emerging as key players in macrophage polarization. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, there is limited knowledge regarding how they affect the macrophage-dependent innate host defense. Materials and methods: We detected the levels of ROS, the ability of chemotaxis, the expressions of markers of M1-/M2-like macrophages in RAW264.7 in presence of T2- and T2C-conditioned medium. Results: The results of this study indicated that ROS levels were decreased in RAW 264.7 cells when cultured with T2C-conditioned medium, while there was an improvement in chemotaxis abilities. We also found that the M2-like macrophages were characterized by an elongated shape in RAW 264.7 cells cultured in T2C-conditioned medium, which had increased CD206 expression but decreased expression of CD86 and inducible nitric oxide synthase. Suppression of ER stress shifted polarized M1-like macrophages toward an M2-like phenotype in RAW 264.7 cells cultured in T2C-conditioned medium. Conclusions: Taken together, we conclude that the polarization of macrophages is associated with the alteration of cell shape, ROS accumulation, and ER stress.