A Transforming Growth Factor-β and H19 Signaling Axis in Tumor-Initiating Hepatocytes That Regulates Hepatic Carcinogenesis

Galangin promotes cell apoptosis through suppression of H19 expression in hepatocellular carcinoma cells

Background

Galangin has been extensively studied as the antitumor agent in various cancers. However, the effect of galangin in hepatocellular carcinoma (HCC) remains elusive.

Methods

Using RNA sequencing, the differential expression of lncRNA in human HCC cell line with highly metastatic potential (MHCC97H) cells treated with galangin was investigated. Furthermore, H19 expression pattern was also determined in MHCC97H cells following treatment with galangin. In addition, knockdown and overexpression of H19 was performed to analyze the effect of the expression pattern of H19 on cell apoptosis, cell cycle, migration, and invasion in HCC cells. Moreover, the in vivo effect of galangin on tumor development was also determined in nude mice. In order to analyze loss expression of H19 in vivo, clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) was used.

Results

Total of 50 lncRNAs were significantly differentially expressed in MHCC97H cells treated with galangin. Besides, the expression of H19 was markedly reduced following treatment with galangin in MHCC97H cells. Compared to the Control group, the galangin‐treated group inhibited cell migration and invasion. Knockdown of H19 expression showed increased cell apoptosis and decreased invasion. In addition, RNA‐seq data also identified 161 mRNA which was significantly differentially expressed following treatment with galangin. To further determine the underlying mechanism, p53 protein was analyzed. Notably, the results indicated that knockdown of H19 and miR675 induced the expression of p53, eventually promoting cell apoptosis in MHCC97H cells. These results indicated that galangin promoted cell apoptosis through reduced the expression of H19 and miR675 in MHCC97H cells. The in vivo result showed that compared to the Con, tumor growth was remarkably suppressed with loss expression of H19.

Conclusion

Our data suggested that galangin has a crucial role in hepatocarcinogenesis through regulating the expression pattern of H19.

Non-Coding RNAs: Regulating Disease Progression and Therapy Resistance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the primary liver cancer arising from hepatocytes, is a universal health problem and one of the most common malignant tumors. Surgery followed by chemotherapy as well as tyrosine kinase inhibitors (TKIs), such as sorafenib, are primary treatment procedures for HCC, but recurrence of disease because of therapy resistance results in high mortality. It is necessary to identify novel regulators of HCC for developing effective targeted therapies that can significantly interfere with progression of the disease process. Non-coding RNAs (ncRNAs) are an abundant group of versatile RNA transcripts that do not translate into proteins, rather serve as potentially functional RNAs. The role of ncRNAs in regulating diverse aspects of the carcinogenesis process are gradually being elucidated. Recent advances in RNA sequencing technology have identified a plethora of ncRNAs regulating all aspects of hepatocarcinogenesis process and serving as potential prognostic or diagnostic biomarkers. The present review provides a comprehensive description of the biological roles of ncRNAs in disease process and therapy resistance, and potential clinical application of these ncRNAs in HCC.

Macrophages-induced long noncoding RNA H19 up-regulation triggers and activates the miR-193b/MAPK1 axis and promotes cell aggressiveness in hepatocellular carcinoma

Dysregulation of long noncoding RNA (lncRNA) H19 has been implicated in hepatocellular carcinoma (HCC), but the concrete regulatory mechanism is lack of research. We mined gene expression profiles of 457 HCC samples from TCGA and TJMUCH cohorts and further validated in 64 FFPE HCC tissues. LncRNA H19 overexpression in situ was significantly correlated with poor prognosis of HCC patients, which induced EMT, promoted stemness and accelerated invasion of HCC cells in vitro. Co-expression network analysis indicated lncRNA H19 negatively correlated with miR-193b and positively correlated with MAPK1 gene, which implicated that lncRNA H19 served as a sponge molecule to hijack miR-193b and protect MAPK1. Forced overexpression of H19 attenuated miR-193b-mediated inhibition on multiple driver oncogenes (EGFR, KRAS, PTEN and IGF1R) and MAPK1 gene, thus triggered EMT and stem cell transformation in HCC. LncRNA H19 positively correlated with CD68 ⁺ TAMs in situ. TAMs-induced lncRNA H19 promotes HCC aggressiveness via triggering and activating the miR-193b/MAPK1 axis, mediates the crosstalk between HCC and immunological microenvironment, and causes poor clinical outcomes. LncRNA H19 is a valuable predictive biomarker and potential therapeutic target in HCC.

The role of long non-coding RNA H19 in breast cancer

Breast cancer is the most common malignant tumor in women in the majority of countries, such as China, Britain and Australia, and its morbidity and mortality rates remain very high. Long non-coding RNAs (lncRNAs) are non-coding RNAs (ncRNAs) >200 nucleotides in length that lack open reading frames. LncRNA H19 is a transcription product of the H19 gene, and the aberrant expression of H19 can be demonstrated in various types of tumor cell. The purpose of the present review was to elaborate the role of H19 in breast cancer. H19 can regulate gene expression in breast cancer at multiple levels, including epigenetic, transcriptional and posttranscriptional. The abnormal expression of H19 is closely associated with the tumorigenesis and progression of breast cancer via different underlying molecular mechanisms, such as encoding microRNA-675, competing endogenous RNA regulation and interacting with MYC. A large number of clinical studies have suggested that H19 can serve as a potential biomarker for the diagnosis of breast cancer. High expression levels of H19 increases the drug resistance of breast cancer cells and is associated with poor prognosis within patients with breast cancer. Therefore, serum H19 levels may have momentous significance in the clinical setting.

Non-coding RNAs: Emerging Regulators of Sorafenib Resistance in Hepatocellular Carcinoma

As the first oral multi-target anti-tumor drug proved for the treatment of patients with advanced liver cancer in 2007, sorafenib has changed the landscape of advanced hepatocellular carcinoma (HCC) treatment. However, drug resistance largely hinders its clinical application. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), and long non-coding (lncRNAs), have recently been demonstrated playing critical roles in a variety of cancers including HCC, while the mechanisms of ncRNAs in HCC sorafenib resistance have not been extensively characterized yet. Herein, we summarize the mechanisms of recently reported ncRNAs involved in sorafenib resistance and discuss the potential strategies for their application in the battle against HCC.

Genetic And Epigenetic Regulation Of E-Cadherin Signaling In Human Hepatocellular Carcinoma

E-cadherin is well known as a growth and invasion suppressor and belongs to the large cadherin family. Loss of E-cadherin is widely known as the hallmark of epithelial-to-mesenchymal transition (EMT) with the involvement of transcription factors such as Snail, Slug, Twist and Zeb1/2. Tumor cells undergoing EMT could migrate to distant sites and become metastases. Recently, numerous studies have revealed how the expression of E-cadherin is regulated by different kinds of genetic and epigenetic alteration, which are implicated in several crucial transcription factors and pathways. E-cadherin signaling plays an important role in hepatocellular carcinoma (HCC) initiation and progression considering the highly mutated frequency of CTNNB1 (27%). Combining the data from The Cancer Genome Atlas (TCGA) database and previous studies, we have summarized the roles of gene mutations, chromosome instability, DNA methylation, histone modifications and non-coding RNA in E-cadherin in HCC. In this review, we discuss the current understanding of the relationship between these modifications and HCC. Perspectives on E-cadherin-related research in HCC are provided.

Noncoding RNAs Act as Tumor-Derived Molecular Components in Inducing Premetastatic Niche Formation

Cancer metastasis has been demonstrated as it is the culmination of a cascade of priming steps. Increasing evidence has shown that tumor-derived molecular components (TDMCs) are known as extra cellular vesicle and nonvesicle factors and serve as versatile intercellular communication vehicles which can mediate signaling in the tumor microenvironment while creating the premetastatic niche. Noncoding RNAs (ncRNAs) as one of the TDMCs have been proved in participating in the formation of the premetastatic niche. Understanding the premetastatic niche formation mechanisms through TDMCs, especially ncRNAs may open a new avenue for cancer metastasis therapeutic strategies. In this review, recent findings regarding ncRNAs function were summarized, and then the interaction with the premetastatic niche formation was studied, which highlight the potential of using ncRNAs for cancer diagnosis and therapeutic effect.

TGF-β-Mediated Epithelial-Mesenchymal Transition and Cancer Metastasis

Transforming growth factor β (TGF-β) is a secreted cytokine that regulates cell proliferation, migration, and the differentiation of a plethora of different cell types. Consistent with these findings, TGF-β plays a key role in controlling embryogenic development, inflammation, and tissue repair, as well as in maintaining adult tissue homeostasis. TGF-β elicits a broad range of context-dependent cellular responses, and consequently, alterations in TGF-β signaling have been implicated in many diseases, including cancer. During the early stages of tumorigenesis, TGF-β acts as a tumor suppressor by inducing cytostasis and the apoptosis of normal and premalignant cells. However, at later stages, when cancer cells have acquired oncogenic mutations and/or have lost tumor suppressor gene function, cells are resistant to TGF-β-induced growth arrest, and TGF-β functions as a tumor promotor by stimulating tumor cells to undergo the so-called epithelial-mesenchymal transition (EMT). The latter leads to metastasis and chemotherapy resistance. TGF-β further supports cancer growth and progression by activating tumor angiogenesis and cancer-associated fibroblasts and enabling the tumor to evade inhibitory immune responses. In this review, we will consider the role of TGF-β signaling in cell cycle arrest, apoptosis, EMT and cancer cell metastasis. In particular, we will highlight recent insights into the multistep and dynamically controlled process of TGF-β-induced EMT and the functions of miRNAs and long noncoding RNAs in this process. Finally, we will discuss how these new mechanistic insights might be exploited to develop novel therapeutic interventions.

Opposing roles and potential antagonistic mechanism between TGF-β and BMP pathways: Implications for cancer progression

The transforming growth factor β (TGF-β) superfamily participates in tumour proliferation, apoptosis, differentiation, migration, invasion, immune evasion and extracellular matrix remodelling. Genetic deficiency in distinct components of TGF-β and BMP-induced signalling pathways or their excessive activation has been reported to regulate the development and progression of some cancers. As more in-depth studies about this superfamily have been conducted, more evidence suggests that the TGF-β and BMP pathways play an opposing role. The cross-talk of these 2 pathways has been widely studied in kidney disease and bone formation, and the opposing effects have also been observed in some cancers. However, the antagonistic mechanisms are still insufficiently investigated in cancer. In this review, we aim to display more evidences and possible mechanisms accounting for the antagonism between these 2 pathways, which might provide some clues for further study in cancer.

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Describe the basics of TGF-β and BMP signalling

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Summarize the potential mechanisms accounting for the antagonism between TGF-β and BMP pathways

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Provide some evidence about the antagonistic effects between pathways observed in some cancers

lncRNA A1BG-AS1 suppresses proliferation and invasion of hepatocellular carcinoma cells by targeting miR-216a-5p

Extensive evidence indicate that long noncoding RNAs (lncRNAs) regulates the tumorigenesis and progression of hepatocellular carcinoma (HCC). However, the expression and biological function of lncRNA A1BG antisense RNA 1 (A1BG-AS1) were poorly known in HCC. Here, we found the underexpression of A1BG-AS1 in HCC via analysis of The Cancer Genome Atlas database. Further analyses confirmed that A1BG-AS1 expression in HCC was markedly lower than that in noncancerous tissues based on our HCC cohort. Clinical association analysis revealed that low A1BG-AS1 expression correlated with poor prognostic features, such as microvascular invasion, high tumor grade, and advanced tumor stage. Follow-up data indicated that low A1BG-AS1 level evidently correlated with poor clinical outcomes of HCC patients. Moreover, forced expression of A1BG-AS1 repressed proliferation, migration, and invasion of HCC cells in vitro. Conversely, A1BG-AS1 knockdown promoted these malignant behaviors in HepG2 cells. Mechanistically, A1BG-AS1 functioned as a competing endogenous RNA by directly sponging miR-216a-5p in HCC cells. Notably, miR-216a-5p restoration rescued A1BG-AS1 attenuated proliferation, migration and invasion of HCCLM3 cells. A1BG-AS1 positively regulated the levels of phosphatase and tensin homolog and SMAD family member 7, which were reduced by miR-216a-5p in HCC cells. Altogether, we conclude that A1BG-AS1 exerts a tumor suppressive role in HCC progression.