MicroRNA-1 properties in cancer regulatory networks and tumor biology

Cigarette smoke induces angiogenic activation in the cancer field through dysregulation of an endothelial microRNA

Cigarette smoke (CS) creates a "cancer field" in the lung that promotes malignant transformation. The molecular changes within this field are not fully characterized. We examined the significance of microRNA-1 (miR-1) downregulation as one of these changes. We found that tumor miR-1 levels in three non-small cell lung cancer cohorts show inverse correlations with the smoking burden. Lung MiR-1 levels follow a spatial gradient, have prognostic significance, and correlate inversely with the molecular markers of injury. In CS-exposed lungs, miR-1 is specifically downregulated in the endothelium. Exposure to CS induces angiogenesis by selectively degrading mature miR-1 via a vascular endothelial growth factor-driven pathway. Applying a multi-step molecular screen, we identified angiogenic genes regulated by miR-1 in the lungs of smokers. Knockdown of one of these genes, Notch homolog protein 3, simulates the anti-angiogenic effects of miR-1. These findings suggest that miR-1 can be used as an indicator of malignant transformation.

Microbiome and Mucosal Immunity in the Intestinal Tract

The human bowel is exposed to numerous biotic and abiotic external noxious agents. Accordingly, the digestive tract is frequently involved in malfunctions within the organism. Together with the commensal intestinal flora, it regulates the immunological balance between inflammatory defense processes and immune tolerance. Pathological changes in this system often cause chronic inflammatory bowel diseases including Crohn's disease and ulcerative colitis. This review article highlights the complex interaction between commensal microorganisms, the intestinal microbiome, and the intestinal epithelium-localized local immune system. The main functions of the human intestinal microbiome include (i) protection against pathogenic microbial colonization, (ii) maintenance of the barrier function of the intestinal epithelium, (iii) degradation and absorption of nutrients and (iv) active regulation of the intestinal immunity. The local intestinal immune system consists primarily of macrophages, antigen-presenting cells, and natural killer cells. These cells regulate the commensal intestinal microbiome and are in turn regulated by signaling factors of the epithelial cells and the microbiome. Deregulated immune responses play an important role and can lead to both reduced activity of the commensal microbiome and pathologically increased activity of harmful microorganisms. These aspects of chronic inflammatory bowel disease have become the focus of attention in recent years. It is therefore important to consider the immunological-microbial context in both the diagnosis and treatment of inflammatory bowel diseases. A promising holistic approach would include the most comprehensive possible diagnosis of the immune and microbiome status of the patient, both at the time of diagnostics and during therapy.

Comprehensive Review of Uterine Leiomyosarcoma: Pathogenesis, Diagnosis, Prognosis, and Targeted Therapy

Uterine leiomyosarcoma (uLMS) is the most common subtype of uterine sarcomas. They have a poor prognosis with high rates of recurrence and metastasis. The five-year survival for uLMS patients is between 25 and 76%, with survival rates approaching 10-15% for patients with metastatic disease at the initial diagnosis. Accumulating evidence suggests that several biological pathways are involved in uLMS pathogenesis. Notably, drugs that block abnormal functions of these pathways remarkably improve survival in uLMS patients. However, due to chemotherapy resistance, there remains a need for novel drugs that can target these pathways effectively. In this review article, we provide an overview of the recent progress in ascertaining the biological functions and regulatory mechanisms in uLMS from the perspective of aberrant biological pathways, including DNA repair, immune checkpoint blockade, protein kinase and intracellular signaling pathways, and the hedgehog pathway. We review the emerging role of epigenetics and epitranscriptome in the pathogenesis of uLMS. In addition, we discuss serum markers, artificial intelligence (AI) combined with machine learning, shear wave elastography, current management and medical treatment options, and ongoing clinical trials for patients with uLMS. Comprehensive, integrated, and deeper insights into the pathobiology and underlying molecular mechanisms of uLMS will help develop novel strategies to treat patients with this aggressive tumor.

Investigating Helicobacter pylori-related pyloric hypomotility: functional, histological, and molecular alterations

Multiple theories have been proposed describing the pathogenic mechanisms of Helicobacter pylori (H. pylori)-associated gastric motility disorders. We assessed ex vivo pyloric activity in H. pylori-infected rats, and tried to explore the associated ghrelin hormone alteration and pyloric fibrogenesis. In addition, miR-1 was assessed in pyloric tissue samples, being recently accused of having a role in smooth muscle dysfunction. Ninety adult male Wistar albino rats were assigned into nine groups: 1) control group, 2) sterile broth (vehicle group), 3) amoxicillin control, 4) omeperazole control, 5) clarithromycin control, 6) triple therapy control, 7) H. pylori- group, 8) H. pylori-clarithromycin group, and 9) H. pylori-triple therapy group. Urease enzyme activity was applied as an indicator of H. pylori infection. Ex vivo pyloric contractility was evaluated. Serum ghrelin was assessed, and histological tissue evaluation was performed. Besides, pyloric muscle miR-1 expression was measured. The immunological epithelial to mesenchymal transition (EMT) markers; transforming growth factor β (TGFβ), α-smooth muscle actin (α-SMA), and E-cadherin-3 were also evaluated. By H. pylori infection, a significant (P < 0.001) reduced pyloric contractility index was recorded. The miR-1 expression was decreased (P < 0.001) in the H. pylori-infected group, associated with reduced serum ghrelin, elevated TGFβ, and α-SMA levels and reduced E-cadherin levels. Decreased miR-1 and disturbed molecular pattern were improved by treatment. In conclusion, H. pylori infection was associated with reduced miR-1, epithelial to mesenchymal transition, and pyloric hypomotility. The miR-1 may be a target for further studies to assess its possible involvement in H. pylori-associated pyloric dysfunction, which might help in the management of human H. pylori manifestations and complications.NEW & NOTEWORTHY This work is investigating functional, histopathological, and molecular changes underlying Helicobacter pylori hypomotility and is correlating these with miR-1, whose disturbance is supposed to be involved in smooth muscle dysfunction and cell proliferation according to literature. Epithelial to mesenchymal transition and reduced ghrelin hormone may contribute to H. pylori infection-associated hypomotility. H. pylori infection was associated with reduced pyloric miR-1 expression. Targeting miR-1 could be valuable in the clinical management of pyloric hypofunction.

Analysis of association between MALAT1 haplotype and the severity of normal-tension glaucoma (NTG)

MALAT1, which is disorderly expressed in the growth, invasion, migration and cancer cell apoptosis, was shown to be associated with normal-tension glaucoma (NTG), a type of optic neuropathy. The haplotype in MALAT1 affects its expression and is correlated with human diseases like normal-tension glaucoma (NTG). However, the underlying detailed mechanism remains unclear. In this study, we aimed to analyse the association between MALAT1 haplotype and the severity of NTG in a molecular level. Quantitative real-time PCR, ELISA and luciferase assays were performed to establish the underlying signalling pathways. RNFL thickness, RA and C/D ratio were calculated for NTG patients. Accordingly, GGGT haplotype was demonstrated to be associated with a decreased risk of NTG. The MALAT1 level in serum of NTG patients carrying GGGT haplotype was significantly decreased compared with NTG patients carrying other haplotypes, along with elevated miR-1 expression and diminished IL-6 expression. NTG patients carrying GGGT haplotype had thicker RNFL and RA, but a smaller C/D ratio. Sequence analysis found potential target sites of miR-1 on MALAT1 and IL-6, and luciferase assay confirmed the inhibitory effect of miR-1 on MALAT1 and IL-6 expression. Meanwhile, MALAT1 also down-regulated miR-1 expression and consequently up-regulated IL-6 expression. This study presented evidence for a regulatory network containing MALAT1, miR-1 and IL-6, and further demonstrated the effect of MALAT1 haplotype on the risk and severity of NTG.

Programmed Death Ligand-1 (PD-L1) Regulated by NRF-2/MicroRNA-1 Regulatory Axis Enhances Drug Resistance and Promotes Tumorigenic Properties in Sorafenib-Resistant Hepatoma Cells

Sorafenib, a multityrosine kinase inhibitor, is a standard treatment for advanced hepatocellular carcinoma (HCC), but the clinical response to sorafenib is seriously limited by drug resistance. Programmed death ligand-1 (PD-L1) is one of the most important inhibitory molecules involved in tumor immune evasion. Recently, it has been reported that PD-L1 could play crucial roles in drug resistance of many kinds of cancers. However, the expression, function, and regulation of PD-L1 in sorafenib-resistant hepatoma cells remain unclear. In this study, we reported that PD-L1 was overexpressed in sorafenib-resistant hepatoma cells, and shRNA-mediated PD-L1 depletion attenuated drug resistance and suppressed the migration, invasion, colony formation, and tumorigenesis in sorafenib-resistant hepatoma cells in vitro and in vivo. Mechanistic investigations indicated that loss of microRNA-1 (miR-1), a tumor-suppressive microRNA, contributed to the PD-L1 upregulation in sorafenib-resistant hepatoma cells, and PD-L1 was a direct regulatory target of miR-1. Further study revealed that an oncogenic transcriptional factor, nuclear factor E2-related factor 2 (NRF-2), was induced in sorafenib-resistant hepatoma cells and inhibited expression of miR-1 in vitro. From molecular mechanism insight back to the functional verification, we eventually demonstrated that miR-1 executed its tumor-suppressive effects on drug resistance and other malignant properties in sorafenib-resistant hepatoma cells partially by PD-L1 inhibition in vitro and in vivo. In conclusion, our data suggested that a NRF-2/miR-1/PD-L1 regulatory axis contributed to the development and maintenance of drug resistance and other tumorigenic properties in sorafenib-resistant hepatoma cells and provided a potential therapeutic target for overcoming sorafenib resistance in HCC.

Downregulation of miR-1 in colorectal cancer promotes radioresistance and aggressive phenotypes

Background: Colorectal cancer (CRC) remains to be one of the most common malignancies worldwide. Various studies have demonstrated that microRNAs (miRs) play a critical role in regulating cancer progression and sensitivity to chemoradiotherapy. miR-1 was found to be aberrantly expressed in CRC. However, it has not been fully elucidated whether miR-1 regulated CRC cell radioresistance. Methods: The expression of miR-1 was detected using quantitative real-time polymerase chain reaction in CRC tissues and cell lines. Colony survival and proliferation were determined using colony formation assay and MTT assay, respectively. Apoptosis and levels of related proteins, Bax and Bcl-2, were detected using flow cytometer assay and western blotting analysis. Migration and invasion were measured using wound healing assay and transwell invasion assay. The levels of invasion-associated proteins, E-cadherin, MMP2 and MMP9, were detected using western blotting analysis. Results: miR-1 was found to be downregulated in CRC tissues and cell lines compared with adjacent normal tissues. In vitro, miR-1 overexpression significantly suppressed colony survival and proliferation, and induced cell apoptosis under irradiation, but no apoptosis was detected without irradiation. Furthermore, miR-1 mimics promoted the expression of Bax and E-cadherin and decreased the expression of Bcl-2, MMP2 and MMP9, and apparently impaired the invasion and migration of CRC cells in synergy with radiotherapy. Conclusion: miR-1 enhanced the radiosensitivity of CRC cells by inducing cell apoptosis and the synergic inhibition of aggressive phenotypes, which may serve as a promising therapeutic target for CRC patients.

Long Noncoding RNA UCA1 Facilitates Endometrial Cancer Development by Regulating KLF5 and RXFP1 Gene Expressions

Objective: Long noncoding RNA urothelial carcinoma associated 1 (UCA1) was found to facilitate endometrial cancer cell metastasis, and high UCA1 expression predicted endometrial cancer development and patients' worsened outcomes. This research aimed to investigate the cancer promoting role and mechanism of UCA1 in endometrial cancer. Materials and Methods: Around 64 endometrioid adenocarcinoma patients' tissue specimens were analyzed by qRT-PCR. Primary endometrial cancer cell culture was established in vitro. UCA1 overexpression or knockdown was executed by adenoviral transduction. Cell proliferation, apoptosis, colony formation, transwell invasion, and epithelia-to-mesenchymal transition of primary endometrial cancer cells were assessed. Interactions among UCA1, microRNAs (miRNAs), and mRNAs were investigated by luciferase reporter assay and argonaute 2 (AGO2)-RNA immunoprecipitation. Nude mouse xenograft assay was used to explore the role of UCA1 in endometrial cancer in vivo. Results: UCA1 was significantly upregulated in endometrial cancer tissues compared to normal tissues. High expression of UCA1 associated with endometrial cancer progression and patients' decreased survival. Overexpressing UCA1 significantly increased the malignancy of primary endometrial cancer cells in vitro, while UCA1 knockdown showed opposite effect. Kruppel-like factor 5 (KLF5) and relaxin like family peptide receptor 1 (RXFP1) were found as two UCA1 co-expressing genes in endometrial cancer. UCA1 increased the malignancy of endometrial cells partially through KLF5, and it increased the relaxin 2-induced endometrial cancer cell metastasis through RXFP1. UCA1 reduced the si-RNA-induced silencing of KLF5 and RXFP1 genes in endometrial cancer cells. MiR-143-3p and miR-1-3p were found to interact with both UCA1 and KLF5 mRNA. In addition, knockdown of UCA1 suppressed tumor growth in endometrial cancer in vivo. Conclusion: UCA1 might facilitate endometrial cancer development by upregulating KLF5 and RXFP1 gene expression by sponging miR-143-3p and miR-1-3p.

miR-4792 Inhibits Acute Myeloid Leukemia Cell Proliferation and Invasion and Promotes Cell Apoptosis by Targeting Kindlin-3

It has been reported that kindlin-3 expression is closely associated with progression of many cancers and microRNA (miRNA) processing. However, the effects and precise mechanisms of kindlin-3 in acute myeloid leukemia (AML) have not been well clarified. Our study aimed to explore the interaction between kindlin-3 and miR-4792 in AML. In our study, we found that the expression of kindlin-3 was dramatically increased in AML samples and cell lines, and the miR-4792 level was significantly downregulated. Interestingly, the low miR-4792 level was closely associated with upregulated kindlin-3 expression in AML samples. Moreover, introduction of miR-4792 dramatically suppressed proliferation and invasion and induced apoptosis of AML cells. We demonstrated that miR-4792 could directly target kindlin-3 by using both bioinformatics analysis and luciferase reporter assay. In addition, kindlin-3 silencing had similar effects with miR-4792 overexpression on AML cells. Overexpression of kindlin-3 in AML cells partially reversed the inhibitory effects of miR-4792 mimic. miR-4792 inhibited cell proliferation and invasion and induced apoptosis of AML cells by directly downregulating kindlin-3 expression, and miR-4792 targeting kindlin-3 was responsible for the regulation of the proliferation, invasion, and apoptosis of AML cells.

Overexpression of MicroRNA-1 in Prostate Cancer Cells Modulates the Blood Vessel System of an In Vivo Hen's Egg Test-Chorioallantoic Membrane Model

BACKGROUND/AIM

In prostate cancer (PC), the formation of new blood vessels is stimulated by hypoxic conditions, androgens, and a number of molecular factors including microRNAs. MicroRNA-1 (miR-1) has been characterized in some tumor entities as anti-angiogenic, but this has not yet been investigated in PC.

MATERIALS AND METHODS

PC cells stably overexpressing miR-1 (LNCaP-miR-1) were incubated on an in vivo hen's egg test-chorioallantoic membrane (HET-CAM) model and compared to maternal LNCaP cells. Cell growth, blood vessel organisation, and total blood vessel area were analysed.

RESULTS

Both matrigel-embedded LNCaP and LNCaP-miR-1 cells formed compact tumor-like cell aggregates on the CAM of the HET-CAM model. Although not quantifiable, bleeding of the CAM and remodelling of the blood vessel network in the CAM indicated an influence of miR-1 on the vascular system. The statistically significant decrease in the total surface area of blood vessels in the visible CAM section to 79.4% of control cells demonstrated the antiangiogenic properties of miR-1 for the first time.

CONCLUSION

MiR-1 had a tumor-suppressive and anti-angiogenic effect in an in vivo PC model. In the clinic, miR-1-mediated anti-angiogenesis would result in reduced tumor supply and increased hypoxic stress inside the tumor. Thus, miR-1 restoration by nucleic acid-based miR-1 mimetics would represent a promising option for future PC therapy.

The Clinical Significance of Changes in the Expression Levels of MicroRNA-1 and Inflammatory Factors in the Peripheral Blood of Children with Acute-Stage Asthma

This study assessed the changes and clinical significance of microRNA-1 (miR-1) and inflammatory factors in the peripheral blood of children with acute-stage asthma. 100 children with acute-stage asthma (study group) and 100 healthy children (control group) were enrolled. For all enrolled children, the peripheral blood levels of miR-1, interleukin-4 (IL-4), IL-5, IL-8, tumor necrosis factor-alpha (TNF-α), and interferon-γ (IFN-γ) were measured. The relative expression levels of miR-1 and IFN-γ in the peripheral blood of children in the study group were significantly lower than those in the control group, whereas expression levels of IL-4, IL-5, IL-8, and TNF-α were significantly higher. Moreover, these levels changed to a greater extent in patients with severe disease (P < 0.05). Further analyses showed that the miR-1 expression level positively correlated with IFN-γ and negatively correlated with IL-4, IL-5, IL-8, and TNF-α expression levels (P < 0.05). ROC curve analysis to identify diagnostic specificity and sensitivity showed that, for diagnosing exacerbation in asthma, the area under the curve (AUC) for miR-1 was the highest (AUC = 0.900, P < 0.05) of all tested markers; this held true for diagnosing severe asthma as well (AUC = 0.977, P < 0.05). Compared to healthy children, children with acute-stage asthma had a low miR-1 expression level and a Th1/Th2 imbalance in their peripheral blood. The changes were closely related, became more exaggerated with an increase in disease severity, and could be used as auxiliary variables for diagnosing asthma exacerbation and evaluating disease severity.

MALAT1 silencing suppresses prostate cancer progression by upregulating miR-1 and downregulating KRAS

Background

Prostate cancer (PC) is the second leading cause of cancer-related deaths among men. Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) performed as an oncogene in multiple cancers including PC. However, the molecular mechanisms of MALAT1 implicated in PC progression have not been thoroughly elaborated.

Materials and methods

Reverse transcription-quantitative polymerase chain reaction assay was used to detect the expressions of MALAT1 and microRNA-1 (miR-1). Protein levels of cleaved poly (ADP-ribose) polymerase, cleaved caspase-3, BAX, bcl-2, and KRAS were determined using a western blot assay. Cell proliferation was assessed by colony formation and MTS assays. Cell migration capacity was examined by transwell migration assay (Corning Incorporated, Corning, NY, USA). Apoptosis rate was measured by flow cytometry via double staining of annexin V-FITC and propidium iodide. Luciferase and RNA immunoprecipitation assays were employed to explore the relationship among miR-1, MALAT1, and KRAS.

Results

MALAT1 expression was upregulated and miR-1 expression was downregulated in PC tissues and cell lines. MALAT1 knockdown inhibited cell proliferation and migration, and promoted cell apoptosis in androgen receptor-negative DU145 and PC3 cells. Molecular mechanism explorations disclosed that MALAT1 acted as a molecular sponge of miR-1 in DU145 cells. Moreover, miR-1 downregulation partly abrogated MALAT1 silencing-mediated anti-proliferative, antimigratory, and proapoptotic effects in DU145 and PC3 cells. Further investigation revealed that KRAS was a target of miR-1 in DU145 cells. MALAT1 acted as a competing endogenous RNA of miR-1, resulting in the increase of KRAS expression in DU145 and PC3 cells. Furthermore, miR-1 overexpression hampered proliferation and migration and promoted apoptosis in DU145 and PC3 cells, while these effects were markedly weakened following KRAS upregulation.

Conclusion

MALAT1 knockdown inhibited proliferation and migration and facilitated apoptosis by upregulating miR-1 and downregulating KRAS in androgen receptor-negative PCa cells, providing a new insight into the molecular basis of MALAT1 and a potential biomarker or therapeutic target for suppressing castration-resistant PC.

miR-133b, a particular member of myomiRs, coming into playing its unique pathological role in human cancer

MicroRNAs, a family of single-stranded and non-coding RNAs, play a crucial role in regulating gene expression at posttranscriptional level, by which it can mediate various types of physiological and pathological process in normal developmental progress and human disease, including cancer. The microRNA-133b originally defined as canonical muscle-specific microRNAs considering their function to the development and health of mammalian skeletal and cardiac muscles, but new findings coming from our group and others revealed that miR-133b have frequently abnormal expression in various kinds of human cancer and its complex complicated regulatory networks affects the tumorigenicity and development of malignant tumors. Very few existing reviews on miR-133b, until now, are principally about its role in homologous cluster (miR-1, −133 and -206s), however, most of constantly emerging new researches now are focused mainly on one of them, so In this article, to highlight the unique pathological role of miR-133b playing in tumor, we conduct a review to summarize the current understanding about one of the muscle-specific microRNAs, namely miR-133b, acting in human cancer. The review focused on the following four aspects: the overview of miR-133b, the target genes of miR-133b involved in human cancer, the expression of miR-133b and regulatory mechanisms leading to abnormal expression of miR-133b.

MicroRNA-1 and MicroRNA-21 Individually Regulate Cellular Growth of Non-malignant and Malignant Renal Cells

BACKGROUND/AIM

Due to its poor prognosis, it is increasingly necessary to understand the biology of renal cell cancer (RCC). Therefore, we investigated the role of microRNAs miR-1 and miR-21 in the growth of RCC cells compared to that of non-malignant renal cells.

MATERIALS AND METHODS

Four malignant cell lines (Caki-1, 786-O, RCC4, A498) were examined regarding their cell growth, microRNA and telomerase expression, and were compared to non-malignant RC-124 renal cells.

RESULTS

Inconsistencies appeared in the panel of RCC cells regarding antiproliferative and proliferative properties of miR-1 and miR-21, respectively. Notably, and most likely due to immortaliziation, non-malignant RC-124 cells exhibited telomerase expression and activity.

CONCLUSION

miR-1 and miR-21 functionality in cancer progression, particularly in tumor growth, may be more dependent on the individual cellular context and may reflect RCC heterogeneity. Thus, both microRNAs, in combination with other stratifying biomarkers, may be useful in terms of RCC diagnosis, prognosis, or treatment response.

High altitude and pre-eclampsia: Adaptation or protection

Adaptive genes of high altitude can also be protective in diseases like preeclampsia, hypertension, and diabetes mellitus, Alzheimer, Parkinson Disease and Cancer, which may result from deregulation of hypoxia pathway. The example of pre-eclampsia and normal pregnancy were studied to see if the hypoxia-induced disorders can be dragged towards adaptation. Here, we analyse the genetic variants that are known to be associated with adaptation to high altitude hypoxia. Our results demonstrated that the genetic variants of EPAS1, ADAM9, and EGLN1 increased approximately three-fold in the cases of preeclampsia compared to normal pregnancy. This may suggest the ability of the hypoxic cells of preeclampsia to respond to the high selective pressure of hypoxia with a higher degree of genetic variability, which can lead to adaptation. Signs of "acclimatisation" were seen both in cases and controls but with higher frequencies in controls. This can be a new approach that follows patients' genetic selection and susceptibility of individuals for adaptability, which could be enhanced by drug development.

Downregulation of miR-1 enhances tumorigenicity and invasiveness in oral squamous cell carcinomas

BACKGROUND/PURPOSE

Cumulative evidence suggest that microRNAs (miRNAs) function as biosignatures of oral squamous cell carcinomas (OSCC). However, the functional roles of miR-1 as well as its downstream targets in the regulation of tumorigenicity in OSCC remain unclear.

METHODS

miRNAs RT-PCR analysis was performed to identify miR-1 as a putative candidate on mediating invasiveness of OSCC cells. Consequently, we elucidated the tumorigenicity of OSCC cells with miR-1 downregulation or overexpression, respectively. Finally, miR-1 on OSCC tumor tissues was examined.

RESULTS

miR-1 levels were significantly downregulated in the malignant OSCC cells. Overexpression of miR-1 significantly reduced migration/invasiveness of OSCC cells. In addition, overexpression of miR-1 decreased cancer stem cells properties. Conversely, downregulation of miR-1 promotes migration and invasiveness in OSCC cells. We have shown that miR-1 is able to target Slug, suppressing their expression. Clinically, lower miR-1 expression was found in patients with advanced nodal metastasis OSCC.

CONCLUSION

miR-1 as novel biosignatures in OSCC lymph node metastatic patients, supporting the development of novel strategies for OSCC treatment.

microRNA-539 suppresses tumor growth and tumorigenesis and overcomes arsenic trioxide resistance in hepatocellular carcinoma

AIMS

Dysregulation of microRNAs (miRNAs) plays a critical role in tumor growth and progression. In this study, we sought to explore the expression and biological roles of miR-539 in hepatocellular carcinoma (HCC).

MAIN METHODS

The expression of miR-539 in human HCC tissues and cell lines was examined. The effects of miR-539 overexpression on cell growth, tumorigenicity, arsenic trioxide resistance of HCC cells were determined. The signaling pathways involved in the action of miR-539 in HCC were also investigated.

KEY FINDINGS

miR-539 was downregulated in HCC tissues and cells, relative to corresponding controls. Overexpression of miR-539 inhibited HCC cell viability and colony formation in vitro and impaired tumorigenesis of HCC cells in vivo. Transfection with miR-539 mimic significantly induced apoptosis in HepG2 cells, which was coupled with reduced expression of anti-apoptotic proteins Bcl-2 and Bcl-xL and decreased phosphorylation of Stat3. Overexpression of a constitutively active form of Stat3 partially blocked miR-539-mediated apoptosis. Enforced expression of miR-539 resensitized arsenic trioxide-resistant HCC cells to arsenic trioxide. Intratumoral delivery of miR-539 mimic significantly retarded the growth of xenograft tumors from arsenic trioxide-resistant HCC cells by about 35%, compared to delivery of control miRNA (P<0.05). In combination with arsenic trioxide, miR-539 mimic yielded about 80% decrease in tumor burden.

SIGNIFICANCE

miR-539 functions as a tumor suppressor in HCC and reexpression of this miRNA offers a potential therapeutic strategy for this disease.

miR-1 Inhibits Cell Growth, Migration, and Invasion by Targeting VEGFA in Osteosarcoma Cells

microRNAs (miRNAs) are small noncoding RNAs and have been shown to play a crucial role in the osteosarcoma (OS) tumorigenesis and progression. VEGFA is a key regulator of angiogenesis and plays an important role in regulation of tumor metastasis. The objective of this study was to determine whether VEGFA was involved in miR-1-mediated suppression of proliferation, migration, and invasion of OS cells. The expression levels of miR-1 were significantly lower in OS tumor tissues than those in adjacent normal tissues and in SAOS-2 and U2OS cell lines compared to a normal osteoblast (NHOst) cell line. VEGFA was upregulated in OS tumor tissues and SAOS-2 and U2OS cell lines. The results of CCK-8 assay and transwell assay showed that miR-1 acted as a tumor suppressor by inhibiting cell proliferation, migration, and invasion in U2OS cells. Dual luciferase reporter assay demonstrated that VEGFA was a direct and functional target gene of miR-1. miR-1 directly inhibits the protein expression of VEGFA via its 3'-UTR. Knockdown of VEGFA by siRNA inhibited proliferation, migration, and invasion of U2OS cells. Our study suggested the potential inhibitory function of miR-1 in OS cell proliferation, migration, and invasion via inhibiting VEGFA.