Circular RNA circ-ITCH inhibits bladder cancer progression by sponging miR-17/miR-224 and regulating p21, PTEN expression

BACKGROUND

Circ-ITCH is a circRNA generated from several exons of itchy E3 ubiquitin protein ligase (ITCH) and tumor suppressor served as a sponge for certain miRNAs targeting their parental transcripts of ITCH. However, the role of circ-ITCH in bladder cancer (BCa) was not reported. In the present study, we investigated the role of circ-ITCH in BCa.

METHODS

Quantitative real-time PCR was used to detect the expression of circ-ITCH and survival analysis was adopted to explore the association between circ-ITCH expression and the prognosis of BCa. BCa cells were stably transfected with lentivirus approach and cell proliferation, migration, invasion, cell cycle and cell apoptosis, as well as tumorigenesis in nude mice were performed to assess the effect of circ-ITCH in BCa. Biotin-coupled probe pull down assay, Biotin-coupled miRNA capture, Fluorescence in situ hybridization and Luciferase reporter assay were conducted to confirm the relationship between the circ-ITCH and the microRNA.

RESULTS

In the present study, we found that circ-ITCH, is down-regulated in BCa tissues and cell lines. BCa patients with low circ-ITCH expression had shortened survival. Enforced- expression of circ-ITCH inhibited cells proliferation, migration, invasion and metastasis both in vitro and in vivo. Mechanistically, we demonstrated that circ-ITCH up-regulates the expression of miR-17 and miR-224 target gene p21 and PTEN through 'sponging' miR-17 and miR-224, which suppressed the aggressive biological behaviors of BCa.

CONCLUSIONS

circ-ITCH acts as a tumor suppressor by a novel circ-ITCH/miR-17, miR-224/p21, PTEN axis, which may provide a potential biomarker and therapeutic target for the management of BCa.

Circular RNA hsa_circ_0004872 inhibits gastric cancer progression via the miR-224/Smad4/ADAR1 successive regulatory circuit

BACKGROUND

Emerging evidence has shown that circular RNAs (circRNAs) play a crucial regulatory role in the occurrence and development of cancer. Exploring the roles and mechanisms of circRNAs in tumorigenesis and progression may help to identify new diagnostic markers and therapeutic targets. In the present study, we investigated the role and regulatory mechanism of hsa_circ_0004872 in gastric cancer (GC).

METHODS

qRT-PCR was used to determine the expression of hsa_circ_0004872 in GC tissues and cells. EdU, CCK-8, transwell and scratch wound healing assays were used to assess the role of hsa_circ_0004872 in GC cell proliferation, invasion and migration, respectively. Subcutaneous and tail vein tumor injections in nude mice were used to assess the role of hsa_circ_0004872 in vivo. RIP assay, biotin-coupled probe pull-down assay, FISH and luciferase reporter assay were performed to confirm the relationship between hsa_circ_0004872 and the identified miRNA. ChIP assay, luciferase reporter assay and western blot were used to determine the direct binding of Smad4 to the promoter of the ADAR1 gene.

RESULTS

In this study, we found that hsa_circ_0004872 was dramatically downregulated in GC tissues compared with adjacent noncancerous tissues. The expression level of hsa_circ_0004872 was associated with tumor size and local lymph node metastasis. Enforced expression of hsa_circ_0004872 inhibited the proliferation, invasion and migration of GC cells, whereas knockdown of hsa_circ_0004872 had the opposite effects. Nude mice experiments showed that ectopic expression of hsa_circ_0004872 dramatically inhibited tumor growth and metastasis in vivo. Moreover, we demonstrated that hsa_circ_0004872 acted as a "molecular sponge" for miR-224 to upregulate the expression of the miR-224 downstream targets p21 and Smad4. Importantly, we found that the RNA-editing enzyme ADAR1 inhibited hsa_circ_0004872 expression and further led to the upregulation of miR-224. Smad4, the downstream target of miR-224, could further affect hsa_circ_0004872 levels by directly binding to the promoter region of ADAR1 to inhibit ADAR1 expression.

CONCLUSIONS

Our findings showed that hsa_circ_0004872 acted as a tumor suppressor in GC by forming a negative regulatory loop consisting of hsa_circ_0004872/miR-224/Smad4/ADAR1. Thus, hsa_circ_0004872 may serve as a potential biomarker and therapeutic target for GC.

Hypoxia-inducible microRNA-224 promotes the cell growth, migration and invasion by directly targeting RASSF8 in gastric cancer

Background

Hypoxia plays an important role in the development of various cancers. MicroRNAs (miRNAs) act as post-transcriptional regulators of gene expression and modulate the tumorigenesis, including gastric cancer. However, the roles and molecular mechanism of miR-224 in gastric cancer under hypoxia remain poorly understood.

Method

Real-time PCR and Northern blot assay were used to examine the effects of hypoxia and HIF-1α on miR-224 expression. Luciferase and ChIP assays were performed to determine whether miR-224 was a transcriptional target of HIF-1α. Then MTT, colony formation, in vitro scratch and invasion assays were used to detect the effects of miR-224 on cell growth, migration and invasion under hypoxia, as well as the in vivo animal study. Luciferase assay and Western blot were performed to validate the targets of miR-224. Functional studies were performed to determine the roles of RASSF8 as that of miR-224 under hypoxia. The effects of RASSF8 knockdown on the transcriptional activity and translocation of NF-κB were investigated using Luciferase assay and Western blot, respectively. Finally, the expression levels of miR-224 and RASSF8 were detected using real-time PCR in gastric cancer tissues as well as lymph node metastasis tissues.

Results

We demonstrated that miR-224 was upregulated by hypoxia and HIF-1α. HIF-1α affected miR-224 expression at the transcriptional level. MiR-224 inhibition suppressed cell growth, migration and invasion induced by hypoxia, while miR-224 overexpression resulted in opposite effects. MiR-224 inhibition also suppressed tumor growth in vivo. We then validated that RASSF8 was a direct target of miR-224. RASSF8 overexpression inhibited cell growth and invasion, while RASSF8 knockdown ameliorated the inhibitory effects of miR-224 inhibition on cell growth and invasion. Furthermore, we found that RASSF8 knockdown enhanced the transcriptional activity of NF-κB and p65 translocation, while RASSF8 overexpression resulted in opposite effects. Inhibition of NF-κB activity by PDTC attenuated the effects of RASSF8 knockdown on cell proliferation and invasion. Finally, miR-224 was upregulated in both gastric cancer tissues and lymph node metastasis positive tissues, while RASSF8 expression was opposite to that of miR-224.

Conclusion

These results indicate that hypoxia-inducible miR-224 promotes gastric cancer cell growth, migration and invasion by downregulating RASSF8 and acts as an oncogene, implying that inhibition of miR-224 may have potential as a therapeutic target for patients with hypoxic gastric tumors.

LncRNA-TUSC7/miR-224 affected chemotherapy resistance of esophageal squamous cell carcinoma by competitively regulating DESC1

BACKGROUND

This study aims to clarify the underlying mechanism for the tumor suppressive function of lnc TUSC7 in chemotherapy resistance of esophageal squamous cell carcinoma (ESCC).

METHODS

TUSC7, miR-224 and DESC1 expressions in ESCC tissues and cells were detected by qRT-PCR. Protein level of DESC1, EGFR and p-AKT were observed by Western blot. Overall survival was calculated using the Kaplan-Meier method. Dual-luciferase reporter gene assay and RIP assay were used to comfirm TUSC7 binding to miR-224, and miR-224 binding to DESC1. Cell proliferation, apoptosis, and colony formation was detected by MTT, Flow Cytometry and Colony formation assays.

RESULTS

TUSC7 was downregulated in ESCC tissues and cells, and low TUSC7 indicated worse overall survival. The analysis of bioinformatics softwares showed that TUSC7 specifically bound to miR-224, and we proved miR-224 was upregulated in ESCC and negatively correlated with TUSC7 expression. Overexpression of TUSC7/inhibition of miR-224 suppressed cell proliferation, colony formation and chemotherapy resistance of ESCC cells, and promoted cell apoptosis. In addition, we confirmed that miR-224 specifically bound to DESC1, and negatively correlated with DESC1. TUSC7 suppressed the proliferation and chemotherapy resistance of ESCC cells by increasing DESC1 expression via inhibiting miR-224. We also confirmed DESC1 inhibited chemotherapy resistance of ESCC cells via EGFR/AKT. Finally, in vivo experiments demonstrated that overexpression of TUSC7 decreased tumor growth and chemotherapy resistance.

CONCLUSION

These findings suggested TUSC7 suppressed chemotherapy resistance of ESCC by downregulating miR-224 to modulate DESC1/EGFR/AKT pathway.

miR-224 promotion of cell migration and invasion by targeting Homeobox D 10 gene in human hepatocellular carcinoma

BACKGROUND AND AIM

MicroRNAs (miRNAs) are small noncoding RNA molecules that control target gene expression and are implicated in the regulation of diverse cellular pathways. In our previous research, we have demonstrated that miR-224 was overexpressed in liver cancer cells and tissues, which was an important factor in the regulation of cell migration and invasion. This study aimed to further explore the regulatory mechanism of miR-224 in the migration and invasion in liver cancer cells.

METHODS

A luciferase reporter assay was used to confirm that the HOXD10 gene was a direct target of miR-224. Quantitative reverse transcriptase-polymerase chain reaction, Western blotting, Transwell migration, and Matrigel invasion assays were performed to clarify the molecular mechanism of miR-224 in the regulation of cell migration and invasion in human hepatocellular carcinoma (HCC).

RESULTS

(i) The expression of miR-224 was strongly upregulated in MHHC97H and MHCC97L cells, and its expression level was significantly associated with cell invasive potential. (ii) The HOXD10 gene was confirmed to be a direct target of miR-224. Compared with normal liver tissues and cells, HOXD10 had lower expression in HCC tissues and cells and inversely regulated HCC cell invasion. (iii) miR-224 promoted expression of the tumor invasion-associated proteins p-PAK4 and MMP-9 by directly targeting HOXD10.

CONCLUSION

Our findings suggest a previously undescribed regulatory pathway in which the miR-224/HOXD10/p-PAK4/MMP-9 signaling pathway contributes to the regulation of cell migration and invasion and provides a new biotarget for HCC treatment.

miR-224 functions as an onco-miRNA in hepatocellular carcinoma cells by activating AKT signaling

microRNAs (miRNAs) are a class of small non-coding RNAs that post-transcriptionally regulate gene expression. Increasing evidence has shown that the deregulation of miRNAs is linked to cancer. The overexpression of miR-224 has been reported in several human cancers. The aim of the present study was to investigate the function of miR-224 in the pathogenetic process of hepatocellular carcinoma (HCC), and the precise mechanism underlying its function. Both gain-of-function and loss-of function assays were conducted through transfection with miR-224 mimics and miR-224 inhibitors in the HepG2 liver carcinoma cell line. The data revealed that miR-224 exerts a significant role in promoting cell proliferation, migration and invasion. Western blot analysis showed that the phosphorylation levels of AKT positively correlated with endogenous levels of miR-224. In addition, results from a dual luciferase reporter assay showed that the expression of the serine/threonine-protein phosphatase 2A 65 kDa regulatory subunit A β isoform (PPP2R1B) is inhibited by miR-224; thus, it appears that PPP2R1B is a candidate target of miR-224 in HCC. These data suggest that miR-224 plays a significant role in HCC, possibly through the activation of the AKT signaling pathway by targeting PPP2R1B.

MicroRNA-224 is implicated in lung cancer pathogenesis through targeting caspase-3 and caspase-7

We recently reported that miR-224 was significantly up-regulated in non-small cell lung cancer (NSCLC) tissues, in particular in resected NSCLC metastasis. We further demonstrated that miR-224 functions as an oncogene in NSCLC by directly targeting TNFAIP1 and SMAD4. However, the biological functions of miR-224 in NSCLC are controversial and underlying mechanisms of miR-224 in the progression and metastasis of lung cancer remain to be further explored. Here we report that caspase3 (CASP3) and caspase7 (CASP7) are previously unidentified targets of miR-224 in NSCLC, and that miR-224 promotes lung cancer cells proliferation and migration in part by directly targeting CASP7 and down-regulating its expression. In addition, miR-224 attenuated TNF-α induced apoptosis by direct targeting of CASP3 resulting in reduction of cleaved PARP1 expression in lung cancer cells. Furthermore, the expression of miR-224 negatively correlates with the expression of CASP7 and CASP3 in tissue samples from patients with lung cancer. Finally, we found that activated NF-κB signaling is involved in the regulation of miR-224 expression in lung cancer. Our study provides new insight in understanding of oncogenic role of miR-224 in the lung cancer pathogenesis and suggests that NF-κB/miR-224/CASP3, 7 pathway could be a putative therapeutic target in lung cancer.

Tumour-suppressive microRNA-224 inhibits cancer cell migration and invasion via targeting oncogenic TPD52 in prostate cancer

Our recent study of the microRNA expression signature of prostate cancer (PCa) revealed that microRNA-224 (miR-224) is significantly downregulated in PCa tissues. Here, we found that restoration of miR-224 significantly inhibits PCa cell migration and invasion. Additionally, we found that oncogenic TPD52 is a direct target of miR-224 regulation. Silencing of the TPD52 gene significantly inhibits cancer cell migration and invasion. Moreover, TPD52 expression is upregulated in cancer tissues and negatively correlates with miR-224 expression. We conclude that loss of tumour-suppressive miR-224 enhances cancer cell migration and invasion in PCa through direct regulation of oncogenic TPD52.

Early diagnostic evaluation of miR-122 and miR-224 as biomarkers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the common lethal types of tumor all over the world. The lethality of HCC accounts for many reasons. One of them, the lack of reliable diagnostic markers at the early stage, in this context, serum miRNAs became promising diagnostic biomarkers. Herein, we aimed to identify the predictive value of two miRNAs (miR-122 and miR-224) in plasma of patients with HCC preceded by chronic HCV infection. Taqman miRNA assays specific for hsa-miR-122 and hsa-miR-224 were used to assess the expression levels of the chosen miRNAs in plasma samples collected from three groups; 40 patients with HCC related to HCV, 40 with CHC patients and 20 healthy volunteers. This study revealed that the mean plasma values of miRNA-122 were significantly lower among HCC group when compared to CHC and control groups (P < 0.001). Whereas, miR-224 mean plasma values were significantly higher among HCC group when compared to both CHC group and control group. Moreover, it was found that miR-122 can predict development of HCC at cut-off value <0.67 (RQ) and (AUC = 0.98, P < 0.001). As regards miR-224, it can predict development of HCC at cut-off value >1.2 (RQ) and (AUC = 0.93, P < 0.001), while the accuracy of AFP to diagnose HCC was (AUC: 0.619; P = 0.06). In conclusion, the expression plasma of miR-122 and miR-224 could be used as noninvasive biomarkers for the early prediction of developing HCC at the early stage.

Extracellular miR-224 as a prognostic marker for clear cell renal cell carcinoma

Exosome-miRNAs (exo-miR) have recently been identified as modulators of cancer progression and distant metastasis. We previously found that intracellular miR-224 is up-regulated and significantly related to cancer invasion and metastasis in clear cell renal cell carcinoma (ccRCC). We therefore investigated the role of exosome miR-224 in ccRCC and explored the interaction between intra- and extracellular miR-224 in renal cell carcinoma. To validate the method for isolating exosomes from blood samples or cell culture media, we examined exosome morphology using transmission electron microscope (TEM). We investigated the relationship between exo-miR-224 expression and patient prognosis in 108 ccRCC patients. We isolated exosomes from a metastatic renal cancer cell line and tested their effects on a primary renal cancer cell line with several functional analyses. We found that the high expression level exo-miR-224 group has significantly shorter progression-free survival, cancer-specific survival, and overall survival compared with the low expression group. In multivariate analysis, a high level of exo-miR-224 was a significant risk factor related to all prognoses investigated. After adding exosomes from a metastatic RCC cell line to a primary RCC cell line, cell proliferation and invasion were increased while the percentage of apoptotic cells was significantly decreased. Intracellular levels of miR-224 were significantly up-regulated in the primary renal cancer cell line. Extracellular miR-224 in exosomes impacts on patient prognosis and is a potential prognostic biomarker for ccRCC patients.

Autophagy-preferential degradation of MIR224 participates in hepatocellular carcinoma tumorigenesis

Autophagy and microRNA (miRNA) are important regulators during cancer cell tumorigenesis. Impaired autophagy and high expression of the oncogenic microRNA MIR224 are prevalent in hepatocellular carcinoma (HCC); however, the relationship between the 2 phenomena remains elusive. In this study, we are the first to reveal that autophagy selectively regulates MIR224 expression through an autophagosome-mediated degradation system. Based on this finding, we further demonstrated that in hepatitis B virus (HBV)-related HCC, aberrant autophagy (low autophagic activity) results in accumulation of MIR224 and decreased expression of the target gene Smad4, which leads to increased cell migration and tumor formation. Preferential recruitment of MIR224 into the autophagosome was clearly demonstrated by a) miRNA in situ hybridization under confocal microscopy, and b) immunogold labeling of MIR224 under electron microscopy compared with a ubiquitously expressed microRNA MIRlet7e/let-7. Furthermore, we found that off-label use of amiodarone, an antiarrhythmic agent, effectively suppressed HCC tumorigenesis through autophagy-mediated MIR224 degradation both in vitro and in vivo. In summary, we identified amiodarone as a new autophagy inducer, which may provide an alternative approach in HCC therapy through a novel tumor suppression mechanism.

Post-transcriptional Regulation of PCSK9 by miR-191, miR-222, and miR-224

Since proprotein convertase subtilisin kexin 9 (PCSK9) discovery, a gene involved in LDL metabolism regulation and cardiovascular diseases (CVD), many therapeutic strategies have been introduced for direct targeting of PCSK9. The main goal of these strategies has been to reduce PCSK9 protein level either by application of antibodies or inhibition of its production. In this study, we have tried to discover microRNAs (miRNAs) which can target, and hence regulate, PCSK9 expression. Using bioinformatics tools, we selected three microRNAs with binding sites on 3′-UTR of PCSK9. The expression level of these miRNAs was examined in three different cell lines using real-time RT-PCR. We observed a reciprocal expression pattern between expression level of miR-191, miR-222, and miR-224 with that of PCSK9. Accordingly, the expression levels were highest in Huh7 cells which expressed the lowest level of PCSK9, compared to HepG2 and A549 cell lines. PCSK9 mRNA level also showed a significant decline in HepG2 cells transfected with the vectors overexpressing the aforementioned miRNAs. Furthermore, the miRNAs target sites were cloned in psiCHECK-2 vector, and a direct interaction of the miRNAs and the PCSK9 3′-UTR putative target sites was investigated by means of luciferase assay. Our findings revealed that miR-191, miR-222, and miR-224 can directly interact with PCSK9 3′-UTR and regulate its expression. In conclusion, our data introduces a role for miRNAs to regulate PCSK9 expression.

MicroRNA-224 regulates self-renewal of mouse spermatogonial stem cells via targeting DMRT1

MicroRNAs (miRs) play a key role in the control of gene expression in a wide array of tissue systems, where their functions include the regulation of self-renewal, cellular differentiation, proliferation and apoptosis. However, the function and mechanisms of individual miRs in regulating spermatogonial stem cell (SSC) homeostasis remain unclear. In the present study, we report for the first time that miR-224 is highly expressed in mouse SSCs. Functional assays using miRNA mimics and inhibitors reveal that miR-224 is essential for differentiation of SSCs. Mechanistically, miR-224 promotes differentiation of SSCs via targeting doublesex and Mab-3-related transcription factor 1 (DMRT1). Moreover, WNT/β-catenin signalling pathway is involved in miR-224-mediated regulation of SSCs self-renewal. We further demonstrate that miR-224 overexpression increases the expression of GFRα1 and PLZF, accompanied by the down-regulation of DMRT1 in mouse testes. Our findings provide novel insights into molecular mechanisms regulating differentiation of SSCs and may have important implications for regulating male reproduction.

A retrospective study of NENs and miR-224 promotes apoptosis of BON-1 cells by targeting PCSK9 inhibition

Neuroendocrine neoplasms (NENs) represent relatively rare tumors. The lack of diagnostic, therapeutic method and prognostic factors makes them a challenge to us. We retrospectively reviewed the data of 205 NENs patients among which 157 cases were followed-up. Proprotein convertase subtilisin/kexin 9 (PCSK9), a regulator of low density lipoprotein cholesterol (LDL-C), was confirmed as a target gene of microRNA-224. We found an increased incidence of NENs from 2012 to 2015. Women were usually diagnosed at earlier stages than men (P < 0.05). Tumor grading was associated with primary tumor site, especially esophagus and cardia NENs all at G3 (P <0.001). Age, tumor grading and LDL-C levels were independent risk factors of digestive NENs. Low LDL-C level was significantly correlated with survival rate and median overall survival (OS, P < 0.05). MicroRNA-224 agomir and PCSK9 siRNA could promote apoptosis and suppress proliferation, invasion of BON-1 cells (P < 0.05), but increase the level of glucocorticoid (GC, P < 0.05). Taken together, age, tumor grading and LDL-C level are independent risk factors of NENs. The miR-224/PCSK9/GC axis binds to tumorigenesis and prognosis of pancreatic NENs (p-NENs).

MicroRNA-224 promotes the sensitivity of osteosarcoma cells to cisplatin by targeting Rac1

Osteosarcoma is the most common primary bone tumour in children and adolescents. Accumulating evidence has shown that microRNAs (miRNAs) participate in the development of almost all types of cancer. Here, we investigated the role of miR‐224 in the development and progression of osteosarcoma. We demonstrated that miR‐224 was down‐regulated in osteosarcoma cell lines and tissues. Lower miR‐224 levels were correlated with shorter survivalin osteosarcoma patients. Furthermore, overexpression of miR‐224 suppressed osteosarcoma cell proliferation, migration and invasion and contributed to the increased sensitivity of MG‐63 cells to cisplatin. We identified Rac1 as a direct target gene of miR‐224 in osteosarcoma. Rac1 expression was up‐regulated in the osteosarcoma cell lines and tissues, and there was an inverse correlation between Rac1 and miR‐224 expression in osteosarcoma tissues. Furthermore, rescuing Rac1 expression decreased the sensitivity of miR‐224‐overexpressing MG‐63 cells to cisplatin. We also demonstrated that ectopic expression of Rac1 promoted the proliferation, migration and invasion of miR‐224‐overexpressing MG‐63 cells. These data suggest that miR‐224 plays a tumour suppressor role in the development of osteosarcoma and is related to the sensitivity of osteosarcoma to cisplatin.

MicroRNA-224 targets ERG2 and contributes to malignant progressions of meningioma

MicroRNA-224 is overexpressed in various malignant tumors with poor prognosis, which plays a critical role in biological processes including cell proliferation, apoptosis and several developmental and physiological progressions. However, the potential association between miR-224 and clinical outcome in patients with meningiomas remains unknown. Here, we investigate miR-224 expression and biological functions in meningiomas. MiR-224 expression was measured by Northern blot analysis and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in meningioma and normal brain tissues. Kaplan-Meier analysis and Cox regression analysis were used to exam its correlation with clinicopathological features and prognostic value. The biological effects of miR-224 on the cell proliferation and apoptosis in meningioma cells were examined by MTT assay and apoptosis assay. We found the expression levels of miR-224 were significantly higher in meningioma tissues than that in normal brain, positively correlated with advanced pathological grade. Kaplan-Meier analysis indicated that meningioma patients with low miR-224 expression exhibited significantly prolonged overall and recurrence-free survival. Furthermore, we demonstrated that ERG2 was an identical candidate target gene of MiR-224 in vitro. Our results indicated that downregulation of miR-224 suppressed cell growth and resulted in the enhancement of cell apoptosis through activation of the ERG2-BAK-induced apoptosis pathway. Our findings imply the miR-224 expression could predict the overall survival and recurrence-free survival of patients with meningioma and it might be a promising therapeutic target for treating malignant meningiomas.

MicroRNA-224 is Readily Detectable in Urine of Individuals with Diabetes Mellitus and is a Potential Indicator of Beta-Cell Demise

MicroRNA (miRNA) are a class of non-coding, 19–25 nucleotide RNA critical for network-level regulation of gene expression. miRNA serve as paracrine signaling molecules. Using an unbiased array approach, we previously identified elevated levels of miR-224 and miR-103 to be associated with a monogenic form of diabetes; HNF1A-MODY. miR-224 is a novel miRNA in the field of diabetes. We sought to explore the role of miR-224 as a potential biomarker in diabetes, and whether such diabetes-associated-miRNA can also be detected in the urine of patients. Absolute levels of miR-224 and miR-103 were determined in the urine of n = 144 individuals including carriers of a HNF1A mutation, participants with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM) and normal controls. Expression levels were correlated with clinical and biochemical parameters. miR-224 was significantly elevated in the urine of carriers of a HNF1A mutation and participants with T1DM. miR-103 was highly expressed in urine across all diabetes cohorts when compared to controls. For both miR-224 and-103, we found a significant correlation between serum and urine levels (p < 0.01). We demonstrate that miRNA can be readily detected in the urine independent of clinical indices of renal dysfunction. We surmise that the differential expression levels of miR-224 in both HNF1A-MODY mutation carriers and T1DM may be an attempt to compensate for beta-cell demise.

Induction of autophagy promotes the growth of early preneoplastic rat liver nodules

Although inhibition of autophagy has been implicated in the onset and progression of cancer cells, it is still unclear whether its dysregulation at early stages of tumorigenesis plays an oncogenic or a tumor suppressor role. To address this question, we employed the Resistant-Hepatocyte rat model to study the very early stages of hepatocellular carcinoma (HCC) development. We detected a different autophagy-related gene expression and changes in the ultrastructural profile comparing the most aggressive preneoplastic lesions, namely those positive for the putative progenitor cell marker cytokeratin-19 (KRT-19) with the negative ones. The ultrastructural and immunohistochemical analyses of KRT-19-positive preneoplastic hepatocytes showed the presence of autophagic vacuoles which was associated with p62, Ambra1 and Beclin1 protein accumulation suggesting that a differential modulation of autophagy occurs at early stages of the oncogenesis in KRT-19-positive vs negative lesions. We observed an overall decrease of the autophagy-related genes transcripts and a strong up-regulation of miR-224 in the KRT-19-positive nodules. Interestingly, the treatment with the autophagy inducer, Amiodarone, caused a marked increase in the proliferation of KRT-19 positive preneoplastic lesions associated with a strong increase of their size; by contrast, Chloroquine, an inhibitor of the autophagic process, led to their reduction. These results show that autophagy modulation is a very early event in hepatocarcinogenesis and is restricted to a hepatocytes subset in the most aggressive preneoplastic lesions. Our findings highlight the induction of autophagy as a permissive condition favouring cancer progression indicating in its inhibition a therapeutic goal to interfere with the development of HCC.

Elevated miR-33a and miR-224 in steatotic chronic hepatitis C liver biopsies

AIM: To assess the expression of selected microRNAs (miRNA) in hepatitis C, steatotic hepatitis C, noninfected steatotic and normal liver tissues.

METHODS: The relative expression levels of miR-21, miR-33a, miR-96, miR-122, miR-125b, miR-221 and miR-224 were determined in 76 RNA samples isolated from 18 non-steatotic and 28 steatotic chronic hepatitis C (CHC and CHC-Steatosis, respectively) cases, 18 non-infected, steatotic liver biopsies of metabolic origin (Steatosis) and 12 normal formalin-fixed paraffin-embedded liver tissues using TaqMan MicroRNA Assays. All CHC biopsy samples were obtained prior to initiating therapy. Patients’ serum biochemical values, which included glucose, triglyceride, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), alkaline phosphatase (AP), were obtained and correlated with relative miRNA expression.

RESULTS: When compared with control non-infected liver samples, miR-122 and miR-221 levels were reduced in CHC-Steatosis (P < 0.03) and in CHC, CHC-Steatosis and Steatosis (P < 0.01). Alternatively, the expression of miR-33a and miR-224 were elevated in CHC-Steatosis and Steatosis in comparison to control tissue (P < 0.01). The levels of miR-33a and miR-224 in CHC-Steatosis (P < 0.02) and miR-224 in Steatosis (P < 0.001) were increased in comparison to CHC samples. By contrast, the expression of miR-21 did not differ statistically between diseased and normal liver samples. Levels of miR-33a correlated negatively with serum AST and AP levels in Steatosis as well as with necroinflammatory grade in CHC, whereas miR-21 correlated positively with AST in Steatosis and displayed negative correlation with triglyceride level in CHC-Steatosis. In contrast, miRNA levels were not correlated with ALT, GGT, cholesterol levels or fibrosis stage.

CONCLUSION: Differences in miRNA expression were observed between CHC and steatotic CHC, CHC and steatotic liver, but not between steatotic CHC and steatotic liver of metabolic origin.

Amiodarone promotes cancer cell death through elevated truncated SRSF3 and downregulation of miR-224

Amiodarone is a widely used class III antiarrhythmic agent which prolongs the action potential and refractory period by blockage of several types of myocardial potassium channels. Emerging evidence suggests that amiodarone sensitize tumor cells in response to chemotherapy. Nevertheless, little is known about the underlying molecular mechanism. To gain further insight, we demonstrated that amiodarone accumulated the population of a premature termination codon-containing isoform of serine and arginine rich splicing factor 3 (SRSF3-PTC) without increasing alternative spliced p53 beta isoform. Amiodarone enhanced reactive oxygen species production and increased cell apoptosis, whereas reduced DNA damage. Moreover, amiodarone suppressed miR-224 and increased its target COX-2 expression. Taken together, our results suggested amiodarone caused cancer cell death might be through increased SRSF3-PTC and miR-224 reduction in a p53-independent manner.

MicroRNA-224 Induces G1/S Checkpoint Release in Liver Cancer

Profound changes in microRNA (miR) expression levels are frequently found in liver cancers compared to the normal liver. In this study, we evaluate the expression of miR-224 in human HCC and CCA, as well as its downstream targets and affected pathways. We show that miR-224 is upregulated in a large cohort of human CCA, similar to its upregulation in human HCC. For the purpose of studying the roles of miR-224 in HCC and CCA, we enforced miR-224 expression in cells. mRNA arrays followed by Ingenuity Pathway Analysis (IPA)-identified putative molecules and pathways downstream of miR-224. Phenotypically, we report that enforced expression of miR-224 increases the growth rate of normal cholangiocytes, CCA cell lines, and HCC cell lines. In addition, we identified, in an unbiased fashion, that one of the major biologic processes affected by miR-224 is Gap1 (G1) to Synthesis (S) transition checkpoint release. We next identified p21, p15, and CCNE1 as downstream targets of miR-224 and confirmed the coordinated downregulation results in the increased phosphorylation of Retinoblastoma (Rb) with resulting G1/S checkpoint release. Our data suggest that miR-224 is a master regulator of cell cycle progression, and that its overexpression results in G1/S checkpoint release followed by accelerated cell growth.

Selenium nanoparticles prevents lead acetate-induced hypothyroidism and oxidative damage of thyroid tissues in male rats through modulation of selenoenzymes and suppression of miR-224

Selenium nanoparticles (Se-NPs) are customizable drug delivery vehicles that show good bioavailability, higher efficacy and lower toxicity than ordinary Se. Pre-treatment of male rats with these NPs has been recently shown to exert a protective effect against chromium-induced thyroid dysfunction. This study, therefore, aimed to investigate and characterize the potential protective mechanism of Se-NPs against lead (Pb) acetate-induced thyrotoxicity. We found that prophylactic and concurrent treatment of Pb acetate-exposed rats with Nano-Se (0.5 mg/kg, i.p) for 15 wk significantly alleviated the decrease in free triiodothyronine (fT3) and free thyroxine (fT4) levels as well as fT3/fT4 ratio% and the increase in thyroid stimulating hormone (TSH) levels to approach control values. This was accompanied by a reduction in the accumulation of Pb in serum and thyroid tissues as well as maintenance of thyroidal pro-oxidant/antioxidant balance and iodothyronine deiodinase type 1 (ID1), an essential enzyme for metabolizing of T4 into active T3, gene expression. Surprisingly, miR-224, a direct complementary target of ID1 mRNA, expression in the thyroid tissues was significantly down-regulated in Nano-Se-pre- and co-treated Pb acetate intoxicated animals. Such changes in miR-224 expression were negatively correlated with the changes in ID1 gene expression and serum fT3 level. These results suggest that Se-NPs can rescue from Pb-induced impairment of thyroid function through the maintenance of selenoproteins and down-regulation of miR-224.

miR-224 Controls Human Colorectal Cancer Cell Line HCT116 Proliferation by Targeting Smad4

Background: Better understanding the molecular mechanisms responsible for the genesis and progression of colorectal cancer would help advance the novel therapeutics. miR-224 has been identified to be elevated in colorectal cancer and promote human colorectal cancer cell line SW480 proliferation and invasion. However, the effect of miRNAs on cancer cell proliferation could be significantly changeable among different cell lines. HCT116 is a commonly used cell line for colorectal cancer study and the target gene responsible for the function of miR-224 in its proliferation is unclear. Methods: miR-224 expression was determined by quantitative reverse transcription polymerase chain reactions (PCRs) in human colorectal cancer tissues compared with their corresponding matched peritumoral tissues. HCT116 cell viability and cell proliferation were determined by CCK-8, EdU incorporation assays and flow cytometry for cell cycle. Target gene of miR-224 was confirmed by Western blots and siRNA for Smad4. Results: miR-224 was significantly increased by 29.49 fold in colorectal cancer tissues compared with their corresponding matched peritumoral tissues based on 12 colorectal cancer patients. miR-224 mimic significantly increased HCT116 cell viability, EdU positive cells rate, and decreased G1 phase cell population and increased S phase cell population. miR-224 inhibitor had opposite effects. Smad4 could be negatively regulated by miR-224 in HCT116 cells and was responsible for its effects in proliferation. Conclusion: miR-224 mediates HCT116 cell proliferation by targeting Smad4.

miR-224 Affects Mammary Epithelial Cell Apoptosis and Triglyceride Production by Downregulating ACADM and ALDH2 Genes

MicroRNAs (miRNAs) are small noncoding RNA molecules that involve in various biological functions by regulating the expressions of target genes. In recent years, many researchers have demonstrated that miR-224 played an important role in regulating lipid metabolism. Therefore, in this study, the target genes of miR-224 were verified and the regulatory role of miR-224 was confirmed in lipid metabolism. In this study, bioinformatics methods were used for primarily predicting the target gene of miR-224 and dual-luciferase reporter system was used for further verify the relationship between miR-224 and its target gene. Then, the miR-224 mimics, miR-224 inhibitor, and miRNA-ShNC were transfected into mammary epithelial cells (MECs), respectively, and the expression of miR-224 and its target genes was detected by quantitative real-time polymerase chain reaction and Western blot. Furthermore, the triglyceride production and cell apoptosis were detected by triglyceride mensuration reagent kit using flow cytometry. The results showed that ACADM and ALDH2 were predicted to be the target genes of miR-224, primarily by bioinformatics analysis. We founded that miR-224 could recognize with ACADM-3'UTR and ALDH2-3'UTR, indicating that the target sites existed in 3'UTR of ACADM and ALDH2. And then, the expressions of miR-224 had negative trend with the levels of ACADM and ALDH2, suggesting that miR-224 could downregulate the expressions of ACADM and ALDH2. Finally, the triglyceride production decreased and apoptosis rate increased after the overexpression of miR-224 in MECs. The above results indicated that miR-224 regulating target genes in lipid metabolism might be used as a new pathway for better breeding.

miR-224 aggravates cancer-associated fibroblast-induced progression of non-small cell lung cancer by modulating a positive loop of the SIRT3/AMPK/mTOR/HIF-1α axis

OBJECTIVES

Cancer-associated fibroblast (CAF) is among the most important tumor-host microenvironment components by affecting tumor progression. This study explored the role of miR-224 in CAF-induced non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

A CAF-NSCLC cell co-culture model was established, and the miR-224 expression in CAF was detected by reverse transcription-polymerase chain reaction (RT-PCR). Gain- and loss- of experiments of miR-224 were implemented to verify the effects of CAF on NSCLC cell proliferation, invasion, and epithelial-mesenchymal transition (EMT), and endothelial cell (EC) angiogenesis. Overexpressing genetic or pharmacological interventions were performed to explore the potential mechanisms of Sirtuins 3/AMP-activated protein kinase/mammalian target of rapamycin/hypoxia-inducible factor-1α (SIRT3/AMPK/mTOR/HIF-1α).

RESULTS

CAF enhanced the malignant phenotype of NSCLC cells and induced EC angiogenesis. miR-224 was significantly altered in CAFs. miR-224 up-regulation exacerbated NSCLC development mediated by CAFs, while miR-224 inhibition mostly reversed CAF-induced effects. Mechanistically, miR-224 targeted the 3'-untranslated regions (UTR) of SIRT3 mRNA, thereby inhibiting SIRT3/AMPK and activating mTOR/HIF-1α. Forced overexpression of SIRT3 up-regulated AMPK and inactivated mTOR/HIF-1α, while inhibiting HIF-1α markedly up-regulated SIRT3/AMPK and reduced mTOR phosphorylation. Interestingly, both Sirt1 overexpression and HIF-1α inhibition repressed miR-224 levels and miR-224-mediated promotive effects in NSCLC.

CONCLUSION

The miR-224-SIRT3/AMPK/mTOR/HIF-1α axis formed a positive feedback loop in modulating CAF-induced carcinogenic effects on NSCLC.