MicroRNA-200a Suppresses Cell Invasion and Migration by Directly Targeting GAB1 in Hepatocellular Carcinoma

The underlying mechanism and targeted therapy strategy of miRNAs cross-regulating EMT process through multiple signaling pathways in hepatocellular carcinoma

The consistent notion holds that hepatocellular carcinoma (HCC) initiation, progression, and clinical treatment failure treatment failure are affected by the accumulation of various genetic and epigenetic alterations. MicroRNAs (miRNAs) play an irreplaceable role in a variety of physiological and pathological states. meanwhile, epithelial-mesenchymal transition (EMT) is a crucial biological process that controls the development of HCC. miRNAs regulate the intermediation state of EMTor mesenchymal-epithelial transition (MTE)thereby regulating HCC progression. Notably, miRNAs regulate key HCC-related molecular pathways, including the Wnt/β-catenin pathway, PTEN/PI3K/AKT pathway, TGF-β pathway, and RAS/MAPK pathway. Therefore, we comprehensively reviewed how miRNAs produce EMT effects by multiple signaling pathways and their potential significance in the pathogenesis and treatment response of HCC. emphasizing their molecular pathways and progression in HCC initiation. Additionally, we also pay attention to regulatory mechanisms that are partially independent of signaling pathways. Finally, we summarize and propose miRNA-targeted therapy and diagnosis and defense strategies forHCC. The identification of the mechanism leading to the activation of EMT programs during HCC disease processes also provides a new protocol for the plasticity of distinct cellular phenotypes and possible therapeutic interventions. Consequently, we summarize the latest progress in this direction, with a promising path for further insight into this fast-moving field.

LncRNA AK001796 promotes cell proliferation via acting as a ceRNA of miR-150 in hepatocellular carcinoma

Long non-coding RNA AK001796 was initially identified altered in lung cancer. Recent research showed it could participate in the prognosis of hepatocellular carcinoma (HCC). However, the general biological role of AK001796 and its underlying mechanisms in HCC remain unclear. Here we demonstrated that the expression level of AK001796 in HCC tissues and cell lines was up-regulated. Silencing AK001796 suppressed the proliferation ability of HCC cells. Through dual luciferase reporter assays and loss/gain of functions studies, we identified that AK001796 could bind to miR-150, a star microRNA, promoting HCC proliferation. Furthermore, it was reported that growth factor receptor binding protein 2-associated binder 1 (GAB1) is a target gene of miR-150. Owing to AK001796 being a decoy for miR-150 and binding the same putative sites of miR-150 as GAB1, we presented that inhibition of miR-150 in AK001796 silencing cells reversed the reduction in GAB1. Subsequently, our findings demonstrated that silencing AK001796 can impair phospho-ERK1/2 and phospho-AKT. In conclusion, our investigation revealed that AK001796 promoted proliferation by enhancing phospho-ERK1/2 and phospho-AKT through AK001796/miR-150/GAB1 axis in HCC. These results provided further evidence for the critical roles of AK001796 accumulating HCC and suggested that AK001796 might act as an HCC biomarker in clinical treatment.

Role of microRNA-regulated cancer stem cells in recurrent hepatocellular carcinoma

Among the most common cancers, hepatocellular carcinoma (HCC) has a high rate of tumor recurrence, tumor dormancy, and drug resistance after initial successful chemotherapy or radiotherapy. A small subset of cancer cells, cancer stem cells (CSCs), exhibit stem cell characteristics and are present in various cancers, including HCC. The dysregulation of microRNAs (miRNAs) often accompanies the occurrence and development of HCC. miRNAs can influence tumorigenesis, progression, recurrence, and drug resistance by regulating CSCs properties, which supports their clinical utility in managing and treating HCC. This review summarizes the regulatory effects of miRNAs on CSCs in HCC with a special focus on their impact on HCC recurrence.

miRNAs inspirations in hepatocellular carcinoma: Detrimental and favorable aspects of key performers

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide. HCC initiation, progression, and therapy failure are all influenced by various variables, including microRNAs (miRNAs). miRNAs are short non-coding RNA sequences that modulate target mRNA expression by deteriorating or repressing translation. miRNAs play an imperative role in HCC pathogenesis by triggering the induction of cancer stem cells (CSCs) and their proliferation, while also delaying apoptosis, sustaining the cell cycle, and inspiring angiogenesis, invasion, and metastasis. Additionally, miRNAs modulate crucial HCC-related molecular pathways such as the p53 pathway, the Wnt/β-catenin pathway, VEGFR2, and PTEN/PI3K/AKT pathway. Consequently, the goal of this review was to give an up-to-date overview of oncogenic and tumor suppressor (TS) miRNAs, as well as their potential significance in HCC pathogenesis and treatment responses, highlighting their underpinning molecular pathways in HCC initiation and progression. Similarly, the biological importance and clinical application of miRNAs in HCC are summarized.

The Mechanism of miR-141 Regulating the Proliferation and Metastasis of Liver Cancer Cells by Targeting STAT4

Background

In recent years, it has been reported that miRNA can be used as one of the markers of tumor diagnosis, treatment, and prognosis (including liver cancer), and it plays an important role in tumorigenesis. However, there are still very few studies on the mechanism and role of miR-141 in liver cancer.

Methods

qRT-PCR was used to test the expressions of miR-141 and STAT4 in collected liver cancer tissues and adjacent tissues, cultured liver cancer cell lines MHCC97H, Hep3B, and Huh7, and normal human liver cells HL7702. After processing the results of the qRT-PCR experiment, liver cancer cell MHCC97H which has the lowest expression level was decided to be taken as the research object. miR-NC, miR-141 mimics, si-NC, si-STAT4, miR-141 mimics and pcDNA-NC, and miR-141 mimics and pcDNA-STAT4 were transfected into MHCC97H cells, respectively. The MTT assay was used to detect the proliferation of each group of cells, and the Transwell test was used to detect the effect of miR-141 on cell proliferation, migration, and invasion. The interaction between miR-141 and STAT4 was verified by the dual-luciferase reporter experiment, and the expression level of Cyclin D1 and MMP2 was detected by the western blot.

Results

Compared with normal cell HL7702, the expression level of miR-141 in liver cancer cell lines was relatively low (P < 0.05) and the expression level of STAT4 in liver cancer cell lines was relatively high (P < 0.05) after testing the expression level of STAT4; transfecting miR-141 mimics or Si-SLBP can inhibit cell proliferation, migration, and invasion; dual-luciferase reporter experiments confirmed that miR-141 can specifically bind to the 3′UTR of STAT4; cotransfection of miR-141 mimics and pcDNA-STAT4 can antagonize the effects of miR-141 mimics on cell proliferation, migration, and invasion.

Conclusion

miR-141 can target the STAT4 gene expression to inhibit the proliferation, migration, and invasion of liver cancer cells.

MicroRNA-486-5p Suppresses Lung Cancer via Downregulating mTOR Signaling In Vitro and In Vivo

Lung cancer is one of the central causes of tumor-related deaths globally, of which non-small cell lung cancer (NSCLC) takes up about 85%. As key regulators of various biological processes, microRNAs (miRNAs) have been verified as crucial factors in NSCLC. To elucidate the role of miR-486-5p in the mTOR pathway, we investigated its role in NSCLC and related signaling. Our results confirmed that miR-486-5p was downregulated in most of human NSCLC tissue samples and cell lines. Further study confirmed that it inhibited NSCLC through repression of the mTOR pathway via targeting both ribosomal proteins S6 kinase A1 (RPS6KA1, RSK) and ribosomal proteins S6 kinase B1 (RPS6KB1, p70S6K), which are critical components of the mTOR signaling. Additionally, miR-486-5p impeded tumor growth in vivo and inhibited tumor metastasis through repression of the epithelial-mesenchymal transition (EMT). Taken together, our study verified the role that miR-486-5p exerts in NSCLC, and its expression pattern in the different stages and morphologies of NSCLC makes it a promising biomarker in the early diagnosis of the disease.

Diterpenoid anthraquinones as chemopreventive agents altered microRNA and transcriptome expressions in cancer cells

OBJECTIVE

Cryptotanshinone (CPT) and dihydrotanshinone (DHT) are diterpenoid anthraquinone compounds extracted from traditional Chinese herbal medicine (TCM). Recent studies have shown that CPT regulates the signal transduction pathways via microRNA (miRNA) alterations. However, few studies have investigated the role of DHT in miRNA alterations affecting cell-signaling pathways. This study aimed to investigate the miRNA alterations and post-transcriptional regulation activities of DHT in comparison to CPT.

METHODS

HepG2 and HT-29 cells were treated with DHT or CPT for 72 h. MiRNA, transcription factor encoding mRNA, and downstream gene expression were determined using real-time quantitative PCR. Protein expression was analyzed using western blotting.

RESULTS

The results revealed that CPT and DHT targeted cell proliferation and apoptosis signaling pathways via miR-15a-5p, miR-27a-5p, miR-100-5p, and miR-200a-5p alterations.In silico target predictions showed that downregulation of epidermal growth factor receptor (EGFR) mRNA expression by DHT might also suppress the expression of STAT family proteins and lead to anti-proliferation effects. We also found that, compared to CPT, DHT might possess higher potency in cell growth regulation via multi-miRNA and transcription factor alterations.

CONCLUSION

This study revealed that CPT and DHT targeted cell proliferation and apoptosis signaling pathways via alterations in miRNAs and transcription factors. In addition, the findings of this study suggest that DHT is more potent than CPT in cancer chemopreventive activities. Therefore, DHT at a low dose is a TCM compound with less toxic side effects and may contribute to the development of natural medicine as a potential cancer chemopreventive agent.

Mechanisms and Functions of MiR-200 Family in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common clinically malignant tumors of the digestive system. It ranks the sixth most common malignant tumor in the world and ranks fourth among cancer-related death worldwide. At present, early diagnosis and prognosis monitoring of hepatocellular carcinoma mainly use alpha-fetoprotein combined with ultrasonography, which leads to clinical frequently missed diagnosis or even misdiagnosis. Therefore, seeking specific diagnostic and monitoring molecules of hepatocellular carcinoma are still hot topics in contemporary medical practice. MicroRNA is an endogenous non-coding small RNA that regulates the expression of the target molecule and participates in various biological processes in vivo. The miR-200 family, the most common celebrity family of microRNAs, is commonly lower expression in a variety of cancers and is closely associated with tumorigenesis and outcome, especially hepatocellular carcinoma. This review mainly discusses the expression changes, specific molecular mechanisms, biological functions and clinical values of miR-200 family in hepatocellular carcinoma. Moreover, we highlighted utilization of miR-200 family as molecular biomarkers for early diagnosis, prognostic monitoring and appropriate therapy in hepatocellular carcinoma.

MicroRNA-200a and microRNA-141 have a synergetic effect on the suppression of epithelial-mesenchymal transition in liver cancer by targeting STAT4

MicroRNAs (miRNAs or miRs) are non-coding small RNAs that target specific messenger RNAs to inhibit protein translation. miR-200a and miR-141 function as tumor suppressors by targeting STAT4. These two miRNAs belong to the same family, and their expression is often decreased in various cancer types, but are located on different chromosomes of the human genome. The present study showed that the expression levels of miR-141 and miR-200a in serum and cells of liver cancer are significantly downregulated. The expression levels of miR-141 and miR-200a are closely associated with clinicopathological features of liver cancer, especially metastasis and invasion. It is first reported that STAT4 is the new common target gene of miR-141 and miR-200a. In the present study, miR-141 and miR-200a were confirmed to inhibit the expression of E-cadherin and vimentin synergistically during epithelial-mesenchymal transition to regulate the proliferation, migration and invasion of liver cancer cells by targeting STAT4. Simultaneous overexpression of miR-200a and miR-141 resulted in stronger effects compared with each miRNA alone. In addition, overexpression of STAT4 significantly reversed the tumor suppressive roles of miR-200a and miR-141 in liver cancer cells. These findings enrich the tumor suppressor mechanisms of the miR-200 family, and may also provide new experimental and theoretical basis for the use of miRNAs for early diagnosis, prognosis and thorough treatment of liver cancer.

Hepatocellular carcinoma (HCC): Epidemiology, etiology and molecular classification

Hepatocellular carcinoma (HCC), the primary malignancy of hepatocytes, is a diagnosis with bleak outcome. According to National Cancer Institute's SEER database, the average five-year survival rate of HCC patients in the US is 19.6% but can be as low as 2.5% for advanced, metastatic disease. When diagnosed at early stages, it is treatable with locoregional treatments including surgical resection, Radio-Frequency Ablation, Trans-Arterial Chemoembolization or liver transplantation. However, HCC is usually diagnosed at advanced stages when the tumor is unresectable, making these treatments ineffective. In such instances, systemic therapy with tyrosine kinase inhibitors (TKIs) becomes the only viable option, even though it benefits only 30% of patients, provides only a modest (~3months) increase in overall survival and causes drug resistance within 6months. HCC, like many other cancers, is highly heterogeneous making a one-size fits all option problematic. The selection of liver transplantation, locoregional treatment, TKIs or immune checkpoint inhibitors as a treatment strategy depends on the disease stage and underlying condition(s). Additionally, patients with similar disease phenotype can have different molecular etiology making treatment responses different. Stratification of patients at the molecular level would facilitate development of the most effective treatment option. With the increase in efficiency and affordability of "omics"-level analysis, considerable effort has been expended in classifying HCC at the molecular, metabolic and immunologic levels. This review examines the results of these efforts and the ways they can be leveraged to develop targeted treatment options for HCC.

Molecular and Functional Roles of MicroRNAs in the Progression of Hepatocellular Carcinoma-A Review

Liver cancer is the fourth leading cause of cancer deaths globally, of which hepatocellular carcinoma (HCC) is the major subtype. Viral hepatitis B and C infections, alcohol abuse, and metabolic disorders are multiple risk factors for liver cirrhosis and HCC development. Although great therapeutic advances have been made in recent decades, the prognosis for HCC patients remains poor due to late diagnosis, chemotherapy failure, and frequent recurrence. MicroRNAs (miRNAs) are endogenous, non-coding RNAs that regulate various molecular biological phenomena by suppressing the translation of target messenger RNAs (mRNAs). miRNAs, which often become dysregulated in malignancy, control cell proliferation, migration, invasion, and development in HCC by promoting or suppressing tumors. Exploring the detailed mechanisms underlying miRNA-mediated HCC development and progression can likely improve the outcomes of patients with HCC. This review summarizes the molecular and functional roles of miRNAs in the pathogenesis of HCC. Further, it elucidates the utility of miRNAs as novel biomarkers and therapeutic targets.

Human Cytomegalovirus miR-US5-2 Downregulation of GAB1 Regulates Cellular Proliferation and UL138 Expression through Modulation of Epidermal Growth Factor Receptor Signaling Pathways

Human cytomegalovirus (HCMV) causes significant disease in immunocompromised individuals, including transplant patients. HCMV establishes latency in hematopoietic stem cells in the bone marrow. The mechanisms governing latency and reactivation of viral replication are complex and not fully understood. HCMV-encoded miRNAs are small regulatory RNAs that reduce protein expression. In this study, we found that the HCMV miRNA miR-US5-2 targets the epidermal growth factor receptor (EGFR) adaptor protein GAB1 which directly affects downstream cellular signaling pathways activated by EGF. Consequently, miR-US5-2 blocks the EGF-mediated proliferation of human fibroblasts. Early growth response gene 1 (EGR1) is a transcription factor activated by EGFR signaling that regulates expression of HCMV UL138. We show that miR-US5-2 regulates UL138 expression through GAB1-mediated downregulation of the signaling pathways that lead to EGR1 expression. These data suggest that miR-US5-2, through downregulation of GAB1, could play a critical role during reactivation from latency by reducing proliferation and UL138 expression.

Regulation of epidermal growth factor (EGF) receptor (EGFR) signaling is critical for the replication of human cytomegalovirus (HCMV) as well as latency and reactivation in CD34⁺ hematopoietic progenitor cells. HCMV microRNAs (miRNAs) provide a means to modulate the signaling activated by EGF through targeting components of the EGFR signaling pathways. Here, we demonstrate that HCMV miR-US5-2 directly downregulates the critical EGFR adaptor protein GAB1 that mediates activation and sustained signaling through the phosphatidylinositol 3-kinase (PI3K) and MEK/extracellular signal-regulated kinase (ERK) pathways and cellular proliferation in response to EGF. Expression of HCMV UL138 is regulated by the transcription factor early growth response gene 1 (EGR1) downstream of EGFR-induced MEK/ERK signaling. We show that by targeting GAB1 and attenuating MEK/ERK signaling, miR-US5-2 indirectly regulates EGR1 and UL138 expression, which implicates the miRNA in critical regulation of HCMV latency.

IMPORTANCE Human cytomegalovirus (HCMV) causes significant disease in immunocompromised individuals, including transplant patients. HCMV establishes latency in hematopoietic stem cells in the bone marrow. The mechanisms governing latency and reactivation of viral replication are complex and not fully understood. HCMV-encoded miRNAs are small regulatory RNAs that reduce protein expression. In this study, we found that the HCMV miRNA miR-US5-2 targets the epidermal growth factor receptor (EGFR) adaptor protein GAB1 which directly affects downstream cellular signaling pathways activated by EGF. Consequently, miR-US5-2 blocks the EGF-mediated proliferation of human fibroblasts. Early growth response gene 1 (EGR1) is a transcription factor activated by EGFR signaling that regulates expression of HCMV UL138. We show that miR-US5-2 regulates UL138 expression through GAB1-mediated downregulation of the signaling pathways that lead to EGR1 expression. These data suggest that miR-US5-2, through downregulation of GAB1, could play a critical role during reactivation from latency by reducing proliferation and UL138 expression.

Functional Link between miR-200a and ELK3 Regulates the Metastatic Nature of Breast Cancer

Triple-negative breast cancer (TNBC) refers to breast cancer that does not have receptors for estrogen, progesterone, and HER2 protein. TNBC accounts for 10–20% of all cases of breast cancers and is characterized by its metastatic aggressiveness, poor prognosis, and limited treatment options. Here, we show that the metastatic nature of TNBC is critically regulated by a functional link between miR-200a and the transcription factor ELK3. We found that the expression levels of miR-200a and the ELK3 mRNA were negatively correlated in the luminal and TNBC subtypes of breast cancer cells. In vitro experiments revealed that miR-200a directly targets the 3’ untranslated region (UTR) of the ELK3 mRNA to destabilize the transcripts. Furthermore, ectopic expression of miR-200a impaired the migration and invasion of TNBC cells by reducing the expression level of the ELK3 mRNA. In in vivo studies, transfection of MDA-MB 231 cells (a claudin-low TNBC cell type) with exogenous miR-200a reduced their extravasation into the lung during 48 h after tail vein injection, and co-transfection of the cells with an expression plasmid harboring ELK3 that lacked an intact 3’UTR recovered their extravasation ability. Overall, our findings provide evidences that miR-200a and ELK3 is functionally linked to regulate invasive characteristics of breast cancers.

The mechanistic, diagnostic and therapeutic novel nucleic acids for hepatocellular carcinoma emerging in past score years

Despite The Central Dogma states the destiny of gene as 'DNA makes RNA and RNA makes protein', the nucleic acids not only store and transmit genetic information but also, surprisingly, join in intracellular vital movement as a regulator of gene expression. Bioinformatics has contributed to knowledge for a series of emerging novel nucleic acids molecules. For typical cases, microRNA (miRNA), long noncoding RNA (lncRNA) and circular RNA (circRNA) exert crucial role in regulating vital biological processes, especially in malignant diseases. Due to extraordinarily heterogeneity among all malignancies, hepatocellular carcinoma (HCC) has emerged enormous limitation in diagnosis and therapy. Mechanistic, diagnostic and therapeutic nucleic acids for HCC emerging in past score years have been systematically reviewed. Particularly, we have organized recent advances on nucleic acids of HCC into three facets: (i) summarizing diverse nucleic acids and their modification (miRNA, lncRNA, circRNA, circulating tumor DNA and DNA methylation) acting as potential biomarkers in HCC diagnosis; (ii) concluding different patterns of three key noncoding RNAs (miRNA, lncRNA and circRNA) in gene regulation and (iii) outlining the progress of these novel nucleic acids for HCC diagnosis and therapy in clinical trials, and discuss their possibility for clinical applications. All in all, this review takes a detailed look at the advances of novel nucleic acids from potential of biomarkers and elaboration of mechanism to early clinical application in past 20 years.

Downregulation of transcription factor TCTP elevates microRNA-200a expression to restrain Myt1L expression, thereby improving neurobehavior and oxidative stress injury in cerebral palsy rats

Transcription factors have already been proposed to work on some human diseases. Yet the role of translationally controlled tumor protein (TCTP) in cerebral palsy (CP) remains elusive. This study intends to examine the mechanism of TCTP on CP by regulating microRNA-200a (miR-200a).CP models of rats were established referring to the internationally recognized improved hypoxic ischemic encephalopathy modeling method. The neuroethology of rats, ultrastructure and pathological condition in brain tissues of rats were observed through several assays. The expression of TCTP, miR-200a, myelin transcription factor 1-like (Myt1L), tyrosine hydroxylase (TH) and inducible nitric oxide synthase (iNOS) along with apoptosis in brain tissues of rats was detected. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in brain tissues of rats were determined. The binding site between miR-200a and Myt1L was analyzed.TCTP and Myt1L were overexpressed and miR-200a was under-expressed in CP rats. Elevated miR-200a ameliorated neurobehavior of CP rats and pathological injury in brain tissues. Elevated miR-200a up-regulated TH, GSH, GSH-Px, and SOD levels, down-regulated iNOS, ROS, MDA, TNF-α, and IL-6 levels, and attenuated neuronal apoptosis in brain tissues of CP rats. Myt1L was a target gene of miR-200a.Altogether, our study suggested that diminution of transcription factor TCTP up-regulates miR-200a to limit Myt1L expression, thereby improving neurobehavior and oxidative stress injury in CP rats.

Downregulation of CENPK suppresses hepatocellular carcinoma malignant progression through regulating YAP1

Background

Several studies have found that centromere protein K (CENPK) is overexpressed in several tumour types and promotes tumor progression. However, there has been little research on the role of CENPK in the progression of hepatocellular carcinoma (HCC).

Materials and methods

The expression of CENPK in HCC tissues was quantified by Western blot and quantitative real-time PCR. Cells were transfected with lentiviral plasmids containing shRNA sequences targeting CENPK and YAP1 to silence the expression of CENPK and YAP1. Cell Counting Kit-8 assay, colony formation assay, wound healing assay, and transwell invasion assay were performed to evaluate cell growth, migration, and invasion of HCC cells. Tumorigenicity assay was used to detect the effect of CENPK on the growth of HCC cells. Western blot assay was performed to investigate the expression of epithelial-mesenchymal transition (EMT) markers and YAP1.

Results

Compared to that in adjacent non-tumor tissues, CENPK was aberrantly upregulated in HCC tumor tissues. Furthermore, CENPK knockdown significantly inhibited proliferation, migration, invasion, and EMT progression in HCC cells. Mechanistically, we identified that YAP1 was responsible for the tumor-suppressive effects of CENPK knockdown in the HCC cells. The inhibitory effects of CENPK silencing on cell proliferation, migration, invasion, and EMT were partially reversed by the restoration of YAP1 expression.

Conclusion

Our results suggested that the CENPK-YAP1-EMT axis plays a critical role in regulating HCC malignant progression, indicating the role of this axis as a potential therapeutic target for HCC.

The Role of MicroRNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers, leading to the second cancer-related death in the global. Although the treatment of HCC has greatly improved over the past few decades, the survival rate of patients is still quite low. Thus, it is urgent to explore new therapies, especially seek for more accurate biomarkers for early diagnosis, treatment and prognosis in HCC. MicroRNAs (miRNAs), small noncoding RNAs, are pivotal participants and regulators in the development and progression of HCC. Great progress has been made in the studies of miRNAs in HCC. The key regulatory mechanisms of miRNAs include proliferation, apoptosis, invasion, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, drug resistance and autophagy in HCC. And exosomal miRNAs also play important roles in proliferation, invasion, metastasis, and drug resistance in HCC by regulating gene expression in the target cells. In addition, some miRNAs, including exosomal miRNAs, can be as potential diagnostic and prediction markers in HCC. This review summarizes the latest researches development of miRNAs in HCC in recent years.

Role of microRNAs in the main molecular pathways of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignant neoplasia. HCC is characterized by a poor prognosis. The need to find new molecular markers for its diagnosis and prognosis has led to a progressive increase in the number of scientific studies on this topic. MicroRNAs (miRNAs) are small non-coding RNA that play a role in almost all main cellular pathways. miRNAs are involved in the regulation of expression of the major tumor-related genes in carcinogenesis, acting as oncogenes or tumor suppressor genes. The aim of this review was to identify papers published in 2017 investigating the role of miRNAs in HCC tumorigenesis. miRNAs were classified according to their role in the main molecular pathways involved in HCC tumorigenesis: (1) mTOR; (2) Wnt; (3) JAK/STAT; (4) apoptosis; and (5) MAPK. The role of miRNAs in prognosis/response prediction was taken into consideration. Bearing in mind that the analysis of miRNAs in serum and other body fluids would be crucial for clinical management, the role of circulating miRNAs in HCC patients was also investigated. The most represented miRNA-regulated pathway in HCC is mTOR, but apoptosis, Wnt, JAK/STAT or MAPK pathways are also influenced by miRNA expression levels. These miRNAs could thus be used in clinical practice as diagnostic, prognostic or therapeutic targets for HCC treatment.

The progress of circular RNAs in various tumors

Circular RNAs (circRNAs), a novel type of non-coding RNAs, presented as covalently closed continuous loops. Recent researches had found that circRNAs could function as microRNA sponges, regulators of gene transcription and encoding proteins. They were relatively stable and expressed widely in cytoplasm, which played important roles in carcinogenesis of cancers, such as esophageal cancer, gastric cancer, colorectal cancer, hepatocarcinoma, bladder cancer, glioma, breast cancer, osteosarcoma and so on. Furthermore, they were involved in many biological functions, like cell proliferation, drug resistance, cell cycle, invasion and metastasis. Therefore, the further studies were meaningful on the mechanism of cancers and circRNAs. In the review, we will summarize the current biogenesis of circRNAs and the roles of them in various cancers, which might be a novel biomarker and therapeutic avenue.

NAC1 promotes the migration of prostate cancer cells and participates in osteoclastogenesis by negatively regulating IFNβ

Nucleus accumbens-associated protein 1 (NAC1), a transcriptional co-regulator, is overexpressed in advanced prostate cancer. However, the NAC1-regulated transcriptome has not been completely explored. In the present study, the functional silencing of NAC1 blocked the migration of prostate cancer cells and suppress osteoclastogenesis. The present study also determined that NAC1 was overexpressed in the highly aggressive prostate cancer cell lines PC-3, DU-145 and LNCaP. NAC1 small interfering RNA treatment of DU-145 cells decreased cell migration, but interestingly had no significant effects on cell proliferation. Furthermore, microarray analysis showed that a group of genes may be associated with the development of prostate cancer after NAC1 knockdown, including interferon-β (IFNβ), which is reported to be involved in osteoclastogenesis, an important factor affecting bone metastasis. The mechanisms of NAC1 function were further explored by co-culture studies using PC-3 and RAW264.7 osteoclast precursor cells, which demonstrated that silencing NAC1 downregulated the genes associated with the activation of osteoclasts. Furthermore, it was revealed that NAC1 had the ability to affect the release of IFNβ into the extracellular environment. Together, these findings indicated that NAC1 promoted cell migration, and that NAC1 may have a key role in osteoclastogenesis.

A Large Set of miRNAs Is Dysregulated from the Earliest Steps of Human Hepatocellular Carcinoma Development

Hepatocellular carcinoma (HCC) typically results from a stepwise process characterized by the development of premalignant lesions, such as low- or high-grade dysplastic nodules (LGDNs and HGDNs, respectively), in a cirrhotic setting. MicroRNAs (miRNAs) are small noncoding RNAs involved in post-transcriptional regulation of gene expression that can act as oncogenes or tumor suppressors. Whether and which miRNAs are involved in the early stages of HCC development remains elusive. Here, small-RNA sequencing was applied to profile miRNA expression in 55 samples (cirrhotic nodules; CNs), LGDNs, HGDNs, early HCCs, and small progressed HCCs, obtained from 17 patients bearing HCCs of different etiologies. An miRNA expression signature of 62 miRNAs distinguishing small progressed HCCs from matched CNs was identified. Interestingly, 52 of these miRNAs discriminated CNs from LGDNs/HGDNs, regardless of etiology, and remained modified along the tumorigenic process. Functional analysis of the predicted mRNA targets of deregulated miRNAs identified common modifications between the early and late stages of HCC development likely involved in the stepwise process of HCC development. Our results demonstrate that miRNA deregulation happens very early in HCC in humans, implying their crucial role in the tumorigenic process. The identification of miRNAs discriminating CNs from neoplastic nodules may have relevant translational implications in early diagnosis.

Involvement of miR-451 in resistance to paclitaxel by regulating YWHAZ in breast cancer

MicroRNAs (miRNAs) have been identified as major post-transcriptional regulators of the initiation and progression of human cancers, including breast cancer. However, the detail role of miR-451 has not been fully elucidated in breast cancer. In this study, we aimed to investigate the biological role and molecular mechanisms of miR-451 in drug resistance in breast cancer cell lines and in xenograft model. We show that miR-451 is decreased in human breast cancer specimens and in paclitaxel-resistant (PR) cells. Ectopic expression of miR-451 could inhibit the cell migration and invasion, promoted apoptosis, induced cell-cycle arrest Furthermore, tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ) was identified as a direct target of miR-451. Remarkably, the expression of YWHAZ is inversely correlated with the level of miR-451 in human breast cancer samples. Co-treatment with miR-451 mimics and YWHAZ-siRNA significantly enhanced YWHAZ knockdown in both SKBR3/PR and MCF-7/PR cells Moreover, miR-451 markedly inhibited expression of β-catenin via YWHAZ and subsequently inhibited downstream gene cyclin D1, c-Myc expression. The results of xenograft model in vivo showed that intratumor injection of miR-451 agomir induced a tumor-suppressive effect in SKBR3/PR drug-resistant xenograft model. Taken together, our findings suggested that miR-451 might be considered as important and potential target in paclitaxel-resistant breast cancer treatment.

Knockdown of Gab1 Inhibits Cellular Proliferation, Migration, and Invasion in Human Oral Squamous Carcinoma Cells

Grb2-associated binder 1 (Gab1) is often aberrant in cancerous cells and tissues, whose alteration is responsible for aggressive phenotypes. In this study, we examined the Gab1 expression in human oral squamous cell carcinoma (OSCC) tissues and investigated the cellular and molecular effect of Gab1 on migration, invasion, and cell growth of the OSCC cell lines SCC15 and SCC25. We found that Gab1 was overexpressed in OSCC tissues and cells, which is related to the protein levels of various molecules associated with cellular proliferation, migration, and invasion. Functional assays identified that Gab1 overexpression promoted cell proliferation and invasion of OSCC cells and inhibited cell apoptosis in the SCC15 and SCC25 cell lines. On the other hand, Gab1 silencing affected the proliferation and invasion of OSCC cells and induced cell apoptosis. Western blot assay identified that Gab1 overexpression suppressed the expression of Cdc20 homolog 1 (Cdh1) and then promoted cell invasion in OSCC cells. Furthermore, Gab1-mediated Cdh1 downregulation was significantly reversed when the cells were subjected to an inhibitor of p-Akt. In conclusion, these results suggested that Gab1 induced malignant progression of OSCC cells probably via activation of the Akt/Cdh1 signaling pathway. Thus, Gab1 may be a potential therapeutic target in the treatment of OSCC patients.