Inhibitions of epithelial to mesenchymal transition and cancer stem cells-like properties are involved in miR-148a-mediated anti-metastasis of hepatocellular carcinoma

Interplay between microRNAs and WNT/β-catenin signalling pathway regulates epithelial-mesenchymal transition in cancer

The WNT/β-catenin signalling implies its significance in maintaining an epithelial cell phenotype, proper cell-cell junctions, and tissue homeostasis. Dysregulation of the members of this pathway involves in the development of cancer and an epithelial-mesenchymal transition (EMT) required for metastasis. Loss of E-cadherin is the major contributor to an EMT process and is largely influenced by the WNT/β-catenin signalling. An E-cadherin/β-catenin complex maintains epithelial integrity and disturbance of this complex and WNT/β-catenin pathway will ultimately lead to the nuclear translocation of β-catenin and transcription of EMT-promoting genes. WNT/β-catenin signalling is controlled by microRNAs (miRNAs), several of which are either up- or downregulated during EMT. The strong association between the expression of the WNT signalling components with miRNAs in the initiation and achievement of an EMT phenotype is suggestive of introducing these miRNAs as therapeutic targets against metastatic tumours. Therefore, this review aims to describe these putative miRNAs in altering the WNT/β-catenin signalling in EMT, and whether targeting them is a useful therapeutic option for human invasive tumours.

Glabridin inhibits cancer stem cell-like properties of human breast cancer cells: An epigenetic regulation of miR-148a/SMAd2 signaling

In breast cancer, the cancer stem cells (CSCs) are thought to be the main cause of metastasis and recurrence. Targeting of CSCs or cancer cells with stem cell-like properties has become a new approach for the treatment of breast cancer. Glabridin (GLA), a phytochemical from the root of Glycyrrhiza glabra, exhibited effective antitumor properties in various human cancer cells. However, the roles of GLA in the regulation of CSC-like properties and the underlying molecular mechanisms remain unclear. Here, we reported that GLA attenuated the CSC-like properties through microRNA-148a (miR-148a)/transforming growth factor beta (TGFβ)-SMAD2 signal pathway in vitro and in vivo. In MDA-MB-231 and Hs-578T breast cancer cell lines, GLA enhanced the expression of miR-148a through DNA demethylation. By targeting of the SMAD2-3'-UTR, miR-148a blocked the expression/activation of SMAD2, and in turn, restored the epithelial characteristics, adhesive abilities, and CSC-like properties. Furthermore, in mouse xenograft models, we also confirmed that GLA attenuated the tumor growth, mesenchymal characteristics, and CSCs-like properties via demethylation-activated miR-148a. Our findings suggested a potential treatment strategy to reduce the CSCs-like properties, and therefore enhance the effectiveness of breast cancer therapy.

miR-148a dependent apoptosis of bladder cancer cells is mediated in part by the epigenetic modifier DNMT1

Urothelial cell carcinoma of the bladder (UCCB) is the most common form of bladder cancer and it is estimated that ~15,000 people in the United States succumbed to this disease in 2013. Bladder cancer treatment options are limited and research to understand the molecular mechanisms of this disease is needed to design novel therapeutic strategies. Recent studies have shown that microRNAs play pivotal roles in the progression of cancer. miR-148a has been shown to serve as a tumor suppressor in cancers of the prostate, colon, and liver, but its role in bladder cancer has never been elucidated. Here we show that miR-148a is down-regulated in UCCB cell lines. We demonstrate that overexpression of miR-148a leads to reduced cell viability through an increase in apoptosis rather than an inhibition of proliferation. We additionally show that miR-148a exerts this effect partially by attenuating expression of DNA methyltransferase 1 (DNMT1). Finally, our studies demonstrate that treating cells with both miR-148a and either cisplatin or doxorubicin is either additive or synergistic in causing apoptosis. These data taken together suggest that miR-148a is a tumor suppressor in UCCB and could potentially serve as a novel therapeutic for this malignancy.

FH535 increases the radiosensitivity and reverses epithelial-to-mesenchymal transition of radioresistant esophageal cancer cell line KYSE-150R

BACKGROUND

Acquired radioresistance has significantly compromised the efficacy of radiotherapy for esophageal cancer. The purpose of this study is to investigate the roles of epithelial-mesenchymal transition (EMT) and the Wnt/β-catenin signaling pathway in the acquirement of radioresistance during the radiation treatment of esophageal cancer.

METHODS

We previously established a radioresistant cell line (KYSE-150R) from the KYSE-150 cell line (a human cell line model for esophageal squamous cell carcinoma) with a gradient cumulative irradiation dose. In this study, the expression of EMT phenotypes and the Wnt/β-catenin signaling pathway proteins were examined by real-time PCR, western blot and immunofluorescence in the KYSE-150R cells. The KYSE-150R cells were then treated with a β-Catenin/Tcf inhibitor FH535. The expressions of nuclear and cytoplasmic β-catenin and EMT markers in KYSE-150R cells were assessed at both mRNA and protein level after FH535 treatment. The radiosensitization effect of FH535 on KYSE-150R was evaluated by CCK8 analysis and a colony forming assay. DNA repair capacities was detected by the neutral comet assays.

RESULTS

KYSE-150R cell line displayed obvious radiation resistance and had a stable genetic ability. EMT phenotype was presented in the KYSE-150R cells with decreased E-cadherin and increased snail and twist expressions. The up-regulated expressions of Wnt/β-catenin signaling pathway proteins (Wnt1, FZD1-4, GSK3β, CTNNB1 and Cyclin D1), the increased phosphorylation of GSK3β, and the decreased phosphorylation of β-catenin were observed in KYSE-150R cells compared with KYSE-150 cells, implicating the activation of the Wnt pathway in KYSE-150R cells. The expression of nuclear β-catenin and nuclear translocation of β-catenin from the cytoplasm was decreased after FH535 treatment. FH535 also reversed EMT phenotypes by increasing E-cadherin expression. The cell proliferation rates of KYSE-150R were dose-dependent and the radiation survival fraction was significantly decreased upon FH535 treatment. Neutral comet assays indicated that FH535 impairs DNA double stranded break repair in KYSE-150R cells.

CONCLUSIONS

Acquisition of radioresistance and EMT in esophageal cancer cells is associated with the activation of the Wnt/β-catenin pathway. EMT phenotypes can be reduced and the radiosensitivity of esophageal cancer cells can be enhanced by inhibiting the Wnt/β-catenin pathway with FH535 treatment.

microRNA-148a dysregulation discriminates poor prognosis of hepatocellular carcinoma in association with USP4 overexpression

Hepatocellular carcinoma (HCC) is classified as a poor prognostic tumor, and becomes frequently aggressive. MicroRNAs emerge as key contributors to tumor progression. This study investigated whether miR-148a dysregulation differentiates poor prognosis of HCC, exploring new targets of miR-148a. miR-148a dysregulation discriminated not only the overall survival and recurrence free survival rates of HCC, but the microvascular invasion. In the human HCC samples, ubiquitin specific protease 4 (USP4) and sphingosine 1-phosphate receptor 1 (S1P1) were up-regulated as the new targets of miR-148a. USP4 and S1P1 were up-regulated in mesenchymal-type liver-tumor cells with miR-148a dysregulation, facilitating migration and proliferation of tumor cells. The inverse relationship between miR-148a and the identified targets was verified in a tumor xenograft model. In the analysis of human samples, the expression of USP4, but not S1P1, correlated with the decrease of miR-148a. In a heterotropic patient-derived HCC xenograft model, USP4 was also overexpressed in G1 and G2 tumors when miR-148a was dysregulated, reflecting the closer link between miR-148a and USP4 for a shift in the expansion phase of tumorgraft. In conclusion, miR-148a dysregulation affects the poor prognosis of HCC. Of the identified targets of miR-148a, USP4 overexpression may contribute to HCC progression towards more aggressive feature.

Regulatory MiR-148a-ACVR1/BMP circuit defines a cancer stem cell-like aggressive subtype of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the third most common cancer in Asia. HCC has heterogeneous etiologic and molecular profiles and a varied response to therapeutics. The high recurrence rate and curtailed survival in this cancer are attributed to its resistance to therapy. The ultimate goal is to develop a more effective personalized therapeutic strategy for HCC, but the first step is to develop a system for classifying the disease on the basis of molecular biomarkers. To that end, we performed mRNA and microRNA (miRNA) expression profiling in 100 HCC tissues. Clustering analysis of informative genes identified two robust subtypes, which were validated by an independent dataset. The subtype characterized by a cancer stem cell-like signature was clinically aggressive and associated with poor survival. Integrated analysis of miRNA and mRNA expression in this subtype showed that miR-148a was expressed at a significantly lower level in these tumors than in the other subtype. MiR-148a has been shown to directly suppress the expression of activin A receptor type 1 (ACVR1), a key receptor in the signaling pathway of the bone morphogenetic proteins (BMPs), which regulate many stem cell markers as well as the clinically important cytokine interleukin-8 (IL-8). Increased expression of ACVR1 and its downstream genes EPCAM, CD24, CD90, and IL-8 was associated with shorter survival in a larger cohort of 227 HCC cases. Introduction of miR-148a resulted in suppressed tumor phenotypes both in vitro and in vivo.

CONCLUSION

We identified a clinically aggressive stem cell-like subtype of HCC that is characterized by an miR-148a-ACVR1-BMP-Wnt circuit. We propose that miR-148a may serve as a prognostic biomarker and therapeutic target for this subtype of HCC.

MiR-155 targets TP53INP1 to regulate liver cancer stem cell acquisition and self-renewal

In liver cancer, miR-155 up-regulation can regulate cancer-cell invasion. However, whether miR-155 expression is associated with liver cancer stem cells (CSCs) remains unknown. Here, we show that miR-155 expression is up-regulated in tumor spheres. Knock-down of miR-155 resulted in suppression of tumor sphere formation, through a decrease in the proportion of CD90(+) and CD133(+) CSCs and in the expression of Oct4, whereas miR-155 overexpression had the opposite effect. TP53INP1 was determined to be involved in the CSCs-like properties that were regulated by miR-155. Thus, miR-155 may play an important role in promoting the generation of stem cell-like cells and their self-renewal by targeting the gene TP53INP1.

Decreased expression and clinical significance of miR-148a in hepatocellular carcinoma tissues

Background

Aberrant expression of microRNA-148a (miR-148a) has been reported in several types of malignancies. However, its expression and clinicopathological significance in hepatocellular carcinoma (HCC) has not been entirely clarified. Our objective was to investigate the clinicopathological contribution of the miR-148a expression in HCC formalin-fixed paraffin-embedded (FFPE) tissues.

Methods

Eighty-nine HCC and their para-cancerous liver tissues were recruited. Total mRNA including miRNA was isolated and miR-148a expression was determined by using real time RT-qPCR. Furthermore, the relationship between the miR-148a level and clinicopathological features was explored.

Results

Significantly lower miR-148a expression in HCC tissues was observed than that in adjacent noncancerous hepatic tissues. miR-148a expression was also correlated to clinical TNM stage, metastasis, status of capsular infiltration and numbers of tumor nodes.

Conclusions

Underexpression of miR-148a might be associated with HCC tumorigenesis and deterioration of HCC. miR-148a might act as a suppressor miRNA of HCC and it therefore has a potential role in prognosis of HCC patients.

Progresses in research of miR-148a in digestive system cancers

MicroRNAs (miRNAs) are a class of small non-protein-coding RNAs, which are often aberrantly expressed in the progression of various malignant tumors. Digestive system cancers are major causes of death all over the world. The finding of miRNAs provides a new direction for the diagnosis and therapy of digestive system cancers. Recent studies have demonstrated that miR-148a is aberrantly down-regulated in various digestive system cancers, including gastric cancer, hepatocellular cancer, pancreatic cancer and colorectal cancer. MiR-148a play a crucial role in the progression of these tumors as a tumor suppressor gene. This article will review the progress in research of miR-148a in digestive system cancers.

MicroRNAs associated with HBV infection and HBV-related HCC

Hepatitis B virus (HBV) infection is a global problem and a major risk factor for hepatocellular carcinoma (HCC). microRNAs (miRNAs) comprise a group of small noncoding RNAs regulating gene expression at the posttranslational level, thereby participating in fundamental biological processes, including cell proliferation, differentiation, and apoptosis. In this review, we summarize the roles of miRNAs in HBV infection, the recently identified mechanism underlying dysregulation of miRNAs in HBV-associated HCC, and their association with hepatocarcinogenesis. Moreover, we discuss the recent advances in the use of circulating miRNAs in the early diagnosis of HCC as well as therapies based on these aberrantly expressed miRNAs.

The repressive effect of miR-148a on TGF beta-SMADs signal pathway is involved in the glabridin-induced inhibition of the cancer stem cells-like properties in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide. Current standard practices for treatment of HCC are less than satisfactory because of cancer stem cells (CSCs)-mediated post-surgical recurrence. For this reason, targeting the CSCs or the cancer cells with CSCs-like properties has become a new approach for the treatment of HCC. GLA exhibits anti-tumor effects in that it attenuates the proliferation, migration, invasion, and angiogenesis of human cancer cells. However, the functions of GLA in the regulation of CSCs-like properties in HCC cells, and the molecular mechanisms underlying in remain obscure. Here we found that GLA attenuated the CSCs-like properties by the microRNA-148a (miR-148a)-mediated inhibition of transforming growth factor beta (TGF-β)/SMAD2 signal pathway in HCC cell lines (HepG2, Huh-7, and MHCC97H). Indeed, GLA inhibited the activations/expressions of both TGFβ-induced and the endogenous SMAD2. Further, GLA improved the expression of miR-148a in a dose/time-dependent manner. MiR-148a, which targeted the SMAD2-3'UTR, decreased the expression and function of SMAD2. Knockdown of miR-148a abolished the GLA-induced inhibition of TGF-β/SMAD2 signal pathway and the CSCs-like properties in HCC cells. Our study found a novel mechanism that GLA inhibits the CSCs-like properties of HCC cells by miR-148a-mediated inhibition of TGF-β/SMAD2 signal pathway, which may help to identify potential targets for the therapies of HCC.

MicroRNA-148a is silenced by hypermethylation and interacts with DNA methyltransferase 1 in hepatocellular carcinogenesis

In general, microRNAs, a class of small (~21 nucleotide) non-coding RNAs, negatively regulate the expression of their target genes. Dysregulation of miRNAs is a common feature in human cancers, but this phenomenon has not been studied extensively in hepatocellular carcinoma (HCC). miR‑148a, a member of the miR-148/152 family, has been found to be downregulated in several tumor types and has been suggested to be a tumor suppressor gene; however, its function in HCC remains unclear. Herein, we describe the epigenetic regulation of miR-148a and its impact on HCC cells. We found that, due to the hypermethylation of its CpG island, miR-148a undergoes methylation-mediated silencing in HCC cell lines. Additionally, DNMT1, the DNA methyltransferase that maintains methylation patterns, is aberrantly upregulated in HCC cell lines, and its overexpression is responsible for hypermethylation of the miR-148a promoter. Intriguingly, the expression of DNMT1, which is a target of miR-148a, is inversely correlated with the expression of miR-148a in HCC cells. These results lead us to propose the existence of a negative feedback regulatory loop between miR-148a and DNMT1 in HCC. Importantly, we demonstrate that the overexpression of miR-148a significantly inhibits HCC cell proliferation and cell cycle progression. Our results suggest the existence of a novel miR-148a-DNMT1 regulatory circuit and indicate that miR-148a acts as a tumor suppressor during hepatocellular carcinogenesis. These results may provide a promising alterative strategy for the therapeutic treatment of HCC.

Cellular reprogramming and hepatocellular carcinoma development

Hepatocellular carcinoma (HCC) is one of the most common cancers, and is also the leading cause of death worldwide. Studies have shown that cellular reprogramming contributes to chemotherapy and/or radiotherapy resistance and the recurrence of cancers. In this article, we summarize and discuss the latest findings in the area of cellular reprogramming in HCC. The aberrant expression of transcription factors OCT4, KLF4, SOX2, c-MYC, NANOG, and LIN28 have been also observed, and the expression of these transcription factors is associated with unfavorable clinical outcomes in HCC. Studies indicate that cellular reprogramming may play a critical role in the occurrence and recurrence of HCC. Recent reports have shown that DNA methylation, miRNAs, tumor microenvironment, and signaling pathways can induce the expression of stemness transcription factors, which leads to cellular reprogramming in HCC. Furthermore, studies indicate that therapies based on cellular reprogramming could revolutionize HCC treatment. Finally, a novel therapeutic concept is discussed: reprogramming control therapy. A potential reprogramming control therapy method could be developed based on the reprogramming demonstrated in HCC studies and applied at two opposing levels: differentiation and reprogramming. Our increasing understanding and control of cellular programming should facilitate the exploitation of this novel therapeutic concept and its application in clinical HCC treatment, which may represent a promising strategy in the future that is not restricted to liver cancer.

Correlation between expression of CDC25A and Doppler ultrasound features in primary hepatocellular carcinoma

AIM: To investigate the expression of cell division cycle 25A (CDC25A) in primary hepatocellular carcinoma (PHC) and to explore its relationship with Doppler ultrasound imaging features.

METHODS: The expression of CDC25A in 86 PHC specimens and matched tumor-adjacent tissue specimens was detected by RT-PCR and Western blot. The imaging features of PHC was analyzed by Doppler ultrasound.

RESULTS: CDC25A was found to be overexpressed in 75.58% (65/86) of PHC cases (P < 0.05). The expression of CDC25A protein was significantly correlated with Doppler ultrasound imaging features including tumor size, blood flow grade, resistance index (RI) and portal vein invasion (all P < 0.05), but not with the number of liver tumor nodes (P > 0.05).

CONCLUSION: CDC25A may play an important role in the development and metastasis of PHC. Detection of CDC25A expression combined with ultrasound imaging may be used clinically for evaluation of treatment response and prognosis in PHC patients.