Knockdown of long non-coding RNA HOTAIR sensitizes hepatocellular carcinoma cell to cisplatin by suppressing the STAT3/ABCB1 signaling pathway

Deciphering STAT3 signaling potential in hepatocellular carcinoma: tumorigenesis, treatment resistance, and pharmacological significance

Hepatocellular carcinoma (HCC) is considered one of the greatest challenges to human life and is the most common form of liver cancer. Treatment of HCC depends on chemotherapy, radiotherapy, surgery, and immunotherapy, all of which have their own drawbacks, and patients may develop resistance to these therapies due to the aggressive behavior of HCC cells. New and effective therapies for HCC can be developed by targeting molecular signaling pathways. The expression of signal transducer and activator of transcription 3 (STAT3) in human cancer cells changes, and during cancer progression, the expression tends to increase. After induction of STAT3 signaling by growth factors and cytokines, STAT3 is phosphorylated and translocated to the nucleus to regulate cancer progression. The concept of the current review revolves around the expression and phosphorylation status of STAT3 in HCC, and studies show that the expression of STAT3 is high during the progression of HCC. This review addresses the function of STAT3 as an oncogenic factor in HCC, as STAT3 is able to prevent apoptosis and thus promote the progression of HCC. Moreover, STAT3 regulates both survival- and death-inducing autophagy in HCC and promotes cancer metastasis by inducing the epithelial-mesenchymal transition (EMT). In addition, upregulation of STAT3 is associated with the occurrence of chemoresistance and radioresistance in HCC. Specifically, non-protein-coding transcripts regulate STAT3 signaling in HCC, and their inhibition by antitumor agents may affect tumor progression. In this review, all these topics are discussed in detail to provide further insight into the role of STAT3 in tumorigenesis, treatment resistance, and pharmacological regulation of HCC.

Exploring a four-gene risk model based on doxorubicin resistance-associated lncRNAs in hepatocellular carcinoma

Background: Liver cancer is a lethal cancer type among which hepatocellular carcinoma (HCC) is the most common manifestation globally. Drug resistance is a central problem impeding the efficiency of HCC treatment. Long non-coding RNAs reportedly result in drug resistance. This study aimed to identify key lncRNAs associated with doxorubicin resistance and HCC prognosis.

Materials and Methods: HCC samples with gene expression profiles and clinical data were accessed from public databases. We applied differential analysis to identify key lncRNAs that differed between HCC and normal samples and between drug-fast and control samples. We also used univariate Cox regression analysis to screen lncRNAs or genes associated with HCC prognosis. The least absolute shrinkage and selection operator (LASSO) was used to identify the key prognostic genes. Finally, we used receiver operating characteristic analysis to validate the effectiveness of the risk model.

Results: The results of this study revealed RNF157-AS1 as a key lncRNA associated with both doxorubicin resistance and HCC prognosis. Metabolic pathways such as fatty acid metabolism and oxidative phosphorylation were enriched in RNF157-AS1-related genes. LASSO identified four protein-coding genes—CENPP, TSGA10, MRPL53, and BFSP1—to construct a risk model. The four-gene risk model effectively classified HCC samples into two risk groups with different overall survival. Finally, we established a nomogram, which showed superior performance in predicting the long-term prognosis of HCC.

Conclusion: RNF157-AS1 may be involved in doxorubicin resistance and may serve as a potential therapeutic target. The four-gene risk model showed potential for the prediction of HCC prognosis.

Functions and underlying mechanisms of lncRNA HOTAIR in cancer chemotherapy resistance

Chemotherapy has been one of the most important treatments for advanced cancer in recent decades. Although the sensitivity rate of initial chemotherapy is high, patients with chemotherapy resistant tumors, experience tumor recurrence. In recent years, many studies have shown that homeobox transcript antisense intergenic RNA (HOTAIR) is involved in many pathological processes including carcinogenesis. The abnormal regulation of a variety of cell functions by HOTAIR, such as apoptosis, the cell cycle, epithelial-mesenchymal transition, autophagy, self-renewal, and metabolism, is associated with chemotherapy resistance. Therefore, there is an urgent need to understand the biology and mechanism underlying the role of HOTAIR in tumor behavior and its potential as a biomarker for predicting the effect of chemotherapy. In this manuscript, we review the mechanisms underlying HOTAIR-related drug resistance and discuss the limitations of current knowledge and propose potential future directions.

Progress of HOTAIR-microRNA in hepatocellular carcinoma

The Hox transcript antisense intergenic RNA (HOTAIR) has been identified as a tumor gene, and its expression in HCC is significantly increased. HOTAIR is associated with the proliferation, invasion, metastasis and poor prognosis of HCC. In addition, HOTAIR can also regulate the expression and function of microRNA by recruiting the polycomb repressive complex 2 (PRC2) and competitive adsorption, thus promoting the occurrence and development of HCC. In this review, we discussed the two mechanisms of HOTAIR regulating miRNA through direct binding miRNA and indirect regulation, and emphasized the role of HOTAIR in HCC through miRNA, explained the regulatory pathway of HOTAIR-miRNA-mRNA and introduced the role of this pathway in HCC proliferation, drug resistance, invasion and metastasis.

Long noncoding RNA HOTAIR regulates the invasion and metastasis of prostate cancer by targeting hepaCAM

Background

The role of HOX transcript antisense RNA (HOTAIR) has been proven to be important in tumorigenesis. However, how this molecule promotes metastasis and invasion in PCa is still unclear.

Methods

The relationship between HOTAIR and hepatocellular adhesion molecule (hepaCAM) in PCa was identified by immunohistochemistry, immunofluorescence, plasmid transfection, quantitative real-time PCR and immunoblotting. The regulatory effects of HOTAIR on hepaCAM and MAPK signalling and their key roles in PCa metastasis were investigated in vitro.

Results

The expression of HOTAIR was inversely correlated with hepaCAM in the blood and tissue of PCa patients. Here, hepaCAM was identified as a novel target gene of HOTAIR and was critical for the invasiveness of PCa. HOTAIR recruited PRC2 to the hepaCAM promoter, resulting in high levels of H3K27me3 and the absence of hepaCAM with an abnormally activated MAPK pathway. Both HOTAIR depletion and EZH2 inhibition could induce hepaCAM re-expression with inhibitory MAPK signalling and decrease the invasive and metastatic capabilities of PCa cells.

Conclusions

This study demonstrates that HOTAIR promotes invasion and metastasis of PCa by decreasing the inhibitory effect of hepaCAM on MAPK signalling. Therefore, the HOTAIR/hepaCAM/MAPK axis may provide a new avenue towards therapeutic strategies and prognostic indicators for advanced prostate cancer.

The Underlying Mechanisms of Noncoding RNAs in the Chemoresistance of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal human malignancies. Chemotherapeutic agents, such as sorafenib and lenvatinib, can improve the outcomes of HCC patients. Nevertheless, chemoresistance has become a major hurdle in the effective treatment of HCC. Noncoding RNAs (ncRNAs), including mircoRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), have been demonstrated to participate in the onset and progression of HCC. Moreover, multiple lines of evidence have indicated that ncRNAs also play a pivotal role in HCC drug resistance. ncRNAs can regulate drug efflux and metabolism, glucose metabolism, cellular death pathways, and malignant characteristics in HCC. A deeper understanding of the molecular mechanisms responsible for ncRNA-mediated drug resistance in HCC will provide new opportunities for improving the treatment of HCC. In this review, we summarize recent findings on the molecular mechanisms by which ncRNAs regulate HCC chemoresistance, as well as their potential clinical implications in overcoming HCC chemoresistance.

HOTAIR Promotes Cisplatin Resistance of Osteosarcoma Cells by Regulating Cell Proliferation, Invasion, and Apoptosis via miR-106a-5p/STAT3 Axis

Osteosarcoma (OS) is a common primary malignant bone tumor among adolescences, and the emergence of multidrug resistance poses a huge challenge for clinical treatment of OS. LncRNA HOTAIR (HOX antisense intergenic RNA) has been reported to be associated with many malignancies, including OS. However, the underlying mechanisms of HOTAIR involved in drug resistance in OS are obscure. Our study showed that HOTAIR was upregulated in cisplatin (DDP)-resistant OS tissues and cells. HOTAIR knockdown decreased the DDP resistance, drug resistance-related gene expression, cell proliferation, and invasion and promoted apoptosis of Saos2/DDP, MG-63/DDP, and U2OS/DDP cells. Mechanism researches displayed that miR-106a-5p was downregulated in DDP-resistant OS tissues and cells. MiR-106a-5p directly bound with HOTAIR and was regulated by HOTAIR. Moreover, STAT3 was inhibited by miR-106a-5p at a post-transcriptional level, and the transfection of miR-106a-5p reversed the upregulation of STAT3 caused by HOTAIR overexpression. The increase or decrease of miR-106a-5p suppressed the effect of HOTAIR upregulation or downregulation on DDP resistance, cell proliferation, invasion, and apoptosis of Saos2/DDP, MG-63/DDP, and U2OS/DDP cells. What's more, the transfection of STAT3 siRNA reversed the decrease of DDP resistance, cell proliferation, and invasion and rescued the increase of apoptosis induced by miR-106a-5p inhibition. These data suggested that HOTAIR enhanced DDP resistance of Saos2/DDP, MG-63/DDP, and U2OS/DDP cells by affecting cell proliferation, invasion, and apoptosis via miR-106a-5p/STAT3 axis.

Recent Progress in Characterizing Long Noncoding RNAs in Cancer Drug Resistance

Drug resistance is an important cause of failure in cancer chemotherapies. A large number of long noncoding RNAs (lncRNAs) have been found to be related to drug resistance in cancers. Therefore, lncRNAs provide potential targets for cancer therapies. The lncRNAs involved in cancer drug resistance are attracting interest from an increasing number of researchers. This review summarizes the latest research on the mechanisms and functions of lncRNAs in cancer drug resistance and envisages their future developments and therapeutic applications. This research suggests that lncRNAs regulate drug resistance through multiple mechanisms. LncRNAs do not affect drug resistance directly; usually, they do so by regulating the expression of some intermediate regulatory factors. In addition, lncRNAs exhibit a diversity of functions in cancer drug resistance. The overexpression of most lncRNAs promotes drug resistance, while a few lncRNAs have inhibitory effects.

Long non-coding RNA TPTEP1 inhibits hepatocellular carcinoma progression by suppressing STAT3 phosphorylation

BACKGROUND

Hepatocellular carcinoma (HCC) is still the most common cause of tumor-related death worldwide and accumulating studies report that long non-coding RNAs (LncRNAs) are closely related with HCC development, metastasis and prognosis. Cisplatinum, a well-known chemotherapeutic drug, has been widely used for treatment of numerous human cancers including HCC. This study aimed to investigate the differential expressions of LncRNAs in HCC cells treated with cisplatinum and its underlying mechanism.

METHODS

The differential expressions of LncRNAs in HCC cells treated with cisplatinum were determined by RNA-seq. The roles of TPTEP1 in HCC development by applying gene function gain and loss analysis in MHCC97H and QYG-7703 cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR), cell proliferation, colony formation, cell invasion and flow cytometry assays. The underlying mechanism of TPTEP1 sensitizing hepatocellular carcinoma cells to cisplatinum was examined by RNA-pull down, western blotting, subcellular fractionation, RNA immunoprecipitation and dual luciferase reporter assays. The effect of TPTEP1 on tumorigenesis in vivo was performed with a subcutaneous xenograft mouse model of HCC. In addition, TPTEP1 expression was detected in clinical tumor tissue samples by qRT-PCR.

RESULTS

LncRNA TPTEP1 was highly expressed in cisplatinum-treated HCC cells, which sensitizes hepatocellular carcinoma cell to cisplatinum-induced apoptosis. TPTEP1 overexpression inhibited, while TPTEP1 knockdown promoted HCC cell proliferation, tumorigenicity and invasion. Furthermore, TPTEP1 exerted its tumor suppressing activities by interacting with signal transducer and activator of transcription 3 (STAT3) to inhibit its phosphorylation, homodimerization, nuclear translocation and down-stream genes transcription. Moreover, TPTEP1 overexpression obviously inhibits tumor masses in vivo in a subcutaneous xenograft mouse model of HCC and TPTEP1 is frequently downregulated in HCC tissues, compared to its corresponding pre-tumor tissues.

CONCLUSION

LncRNA TPTEP1 inhibits hepatocellular carcinoma cells progression by affecting IL-6/STAT3 signaling. Taken together, our findings suggest a tumor suppressing role of TPTEP1 in HCC progression and provide a novel understanding of TPTEP1 during the chemotherapy for HCC.

Epitranscriptomic Signatures in lncRNAs and Their Possible Roles in Cancer

In contrast to the amazing exponential growth in knowledge related to long non-coding RNAs (lncRNAs) involved in cell homeostasis or dysregulated pathological states, little is known so far about the links between the chemical modifications occurring in lncRNAs and their function. Generally, ncRNAs are post-transcriptional regulators of gene expression, but RNA modifications occurring in lncRNAs generate an additional layer of gene expression control. Chemical modifications that have been reported in correlation with lncRNAs include m⁶A, m⁵C and pseudouridylation. Up to date, several chemically modified long non-coding transcripts have been identified and associated with different pathologies, including cancers. This review presents the current level of knowledge on the most studied cancer-related lncRNAs, such as the metastasis associated lung adenocarcinoma transcript 1 (MALAT1), the Hox transcript antisense intergenic RNA (HOTAIR), or the X-inactive specific transcript (XIST), as well as more recently discovered forms, and their potential roles in different types of cancer. Understanding how these RNA modifications occur, and the correlation between lncRNA changes in structure and function, may open up new therapeutic possibilities in cancer.

Epithelial Mesenchymal and Endothelial Mesenchymal Transitions in Hepatocellular Carcinoma: A Review

PURPOSE

To present a comprehensive review of the literature data, published between 2000 and 2019 on the PubMed and Web of Science databases, in the field of the tumor microenvironment in hepatocellular carcinoma (HCC). All the data were combined with the personal experiences of the authors.

DESIGN

From 1002 representative papers, we selected 86 representative publications which included data on epithelial-to-mesenchymal transition (EMT), angiogenesis, cancer stem-like cells (CSCs), and molecular background of chemoresistance or resistance to radiotherapy.

RESULTS

Although the central event concerns activation of the Wnt/β-catenin pathway, other signal pathways, such as c-Met/HGF/Snail, Notch-1/NF-κB, TGF-β/SMAD, and basic fibroblast growth factor-related signaling, play a role in the EMT of HCC cells. This pathway is targeted by specific miRNAs and long noncoding RNAs, as explored in this paper. A central player in the tumor microenvironment proved to be the CSCs which can be marked by CD133, CD44, CD90, EpCAM, and CD105. CSCs can induce resistance to cytotoxic therapy or, alternatively, can be synthesized, de novo, after chemo- or radiotherapy, especially after transarterial chemoembolization- or radiofrequency ablation-induced hypoxia. The circulating tumor cells proved to have epithelial, intermediate, or mesenchymal features; their properties have a critical prognostic role.

CONCLUSION

The metastatic pathway of HCC seems to be related to the Wnt- or, rather, TGFβ1-mediated inflammation-angiogenesis-EMT-CSCs crosstalk link. Molecular therapy should target this molecular axis controlling the HCC microenvironment.

Non-coding RNA in drug resistance of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has been one of the most highly lethal cancers. The acquisition of drug resistance accounts for the majority of poor effects of chemotherapy in HCC. Non-coding RNAs (ncRNAs) including miRNAs, long ncRNAs (lncRNAs), and circular RNA (circRNA) have been well-documented to participate in cancer occurrence and progression. Recently, multiple studies have highlighted the key roles of ncRNAs in chemoresistance of HCC. In addition, accumulating evidence has demonstrated that they can serve as biomarkers in diagnosis, treatment, and prognosis of HCC. In this review, we first overviewed up-to-date findings regarding miRNA and lncRNA in drug resistance of HCC, then summarized specific mechanisms that they modulate chemoresistance of HCC, and finally discussed their potential clinical application in overcoming the obstacle of HCC chemoresistance in the future.

High LINC01605 expression predicts poor prognosis and promotes tumor progression via up-regulation of MMP9 in bladder cancer

The advent of high-throughput sequencing methods has facilitated identification of novel long non-coding RNAs (lncRNAs), which have been demonstrated to play an important role in multiple tumors. Moreover, with the assistance of bioinformatics analysis, LINC01605 has been found to be up-regulated in bladder cancer (BC) tissues compared with normal tissues. Hence, the present study was to explore its specific biological role and related mechanism in BC. The relative expression level of LINC01605 was measured in a cohort of BC tissues with matched normal tissues as well as human BC cell lines by quantitative real-time PCR (qRT-PCR). Survival analysis was performed to explore the relationship between LINC01605 expression and the prognosis of BC patients. The biological function of LINC01605 was studied in vitroand in vivo, by means of CCK-8 assay, colony formation assay, transwell assay, and tumor xenografts mice model. LINC01605 was found to be frequently highly expressed in both human BC cells and tissues. Survival analysis indicated that high LINC01605 expression was associated with higher histological grade and clinical stages. In addition, down-regulated LINC01605 in BC cells could significantly inhibit the abilities of proliferation, migration, and invasion in vitro and knockdown of LINC01605 in subcutaneous xenograft tumor model could impede tumorigenesis in vivo. Mechanistically, LINC01605 could activate epithelial–mesenchymal transition (EMT) signaling pathway and promote the expression of matrix metallopeptidase (MMP) 9 (MMP9). In summary, our results shed light on that LINC01605, as a new prognostic biomarker, could promote the proliferation, migration, and invasion of BC cells via activating EMT signaling pathway and up-regulating MMP9 expression.

A Systematic Review of Long Noncoding RNAs in Hepatocellular Carcinoma: Molecular Mechanism and Clinical Implications

Hepatocellular carcinoma (HCC) has the second highest mortality rate worldwide among all cancers. Previous studies have revealed the significant involvement of long noncoding RNAs (lncRNAs) in numerous human cancers including HCC. Both oncogenic and tumor repressive lncRNAs have been identified and implicated in the complex process of hepatocarcinogenesis. They can be further explored as prospective diagnostic, prognostic, and therapeutic markers for HCC. An in-depth understanding of lncRNAs' mechanism in HCC is therefore required to fully explore their potential role. In the current review, we will concentrate on the underlying function, molecular mechanisms, and potential clinical implications of lncRNA in HCC.