MicroRNA-98 ameliorates doxorubicin-induced cardiotoxicity via regulating caspase-8 dependent Fas/RIP3 pathway

Cardiotoxicity is one of the primary limitations in the clinical use of the anticancer drug doxorubicin (DOX). However, the role of microRNAs (miRNAs) in DOX-induced cardiomyocyte death has not yet been covered. To investigate this, we observed a significant increase in miR-98 expression in neonatal rat ventricular myocytes after DOX treatment, and MTT, LIVE/Dead and Viability/Cytotoxicity staining showed that miR-98 mimic inhibited DOX-induced cell death. This was also confirmed by Flow cytometry and Annexin V-FITC/PI staining. Interestingly, the protein expression of caspase-8 was upregulated by miR-98 mimics during this process, whereas Fas and RIP3 were downregulated. In addition, the effect of miR-98 against the expression of Fas and RIP3 were restored by the specific caspase-8 inhibitor Z-IETD-FMK. Thus, we demonstrate that miR-98 protects cardiomyocytes from DOX-induced injury by regulating the caspase-8-dependent Fas/RIP3 pathway. Our findings enhance understanding of the therapeutic role of miRNAs in the treatment of DOX-induced cardiotoxicity.

HOXA11-AS induces cisplatin resistance by modulating the microRNA-98/PBX3 axis in nasopharyngeal carcinoma

Long non-coding RNA homeobox A11-antisense RNA (HOXA11-AS) has been implicated in cisplatin (DDP) resistance in multiple types of cancer. The purpose of the present study was to investigate the role of HOXA11-AS in DDP-resistant nasopharyngeal carcinoma (NPC) cells. The expression levels of HOXA11-AS were examined using reverse transcription-quantitative PCR. Cell viability was measured using a Cell Counting Kit-8 assay, and a TUNEL assay was utilized to assess cell apoptosis. The expression levels of apoptosis-related factors (Bax and Bcl-2) were detected by western blot analysis. The interaction between microRNA-98 (miR-98) and HOXA11-AS or pre-B-cell leukemia homeobox 3 (PBX3) was demonstrated using bioinformatics analysis, dual-luciferase reporter assays and RNA immunoprecipitation assays. HOXA11-AS and PBX3 expressions levels were upregulated, whereas miR-98 levels were downregulated in DDP-resistant NPC tissues. Patients with NPC with high HOXA11-AS expression had a low survival rate. Knockdown of HOXA11-AS enhanced the DDP sensitivity of DDP-resistant NPC (5-8F/DDP and SUNE1/DDP) cells, which was demonstrated by the accelerated apoptosis. In addition, HOXA11-AS inhibited the expression levels of miR-98 through direct interaction. Furthermore, miR-98 inhibition counteracted the inductive effect of HOXA11-AS-knockdown on the DDP sensitivity of NPC cells. PBX3 was a target of miR-98 and was positively modulated by HOXA11-AS. Overexpression of PBX3 reversed the suppressive effect of HOXA11-AS silencing on the DDP resistance of NPC cells. The data demonstrated that HOXA11-AS enhanced DDP resistance in NPC via the miR-98/PBX3 axis, providing a potential therapeutic target for patients with DDP-resistant NPC.

Diminution of microRNA-98 alleviates renal fibrosis in diabetic nephropathy by elevating Nedd4L and inactivating TGF-β/Smad2/3 pathway

MicroRNAs (miRNAs) have already been documented to function in diabetic nephropathy (DN), yet little research has focused on the role of miR-98 in this disease. Here, we discuss the mechanism of miR-98 on the renal fibrosis in DN. Recombinant adeno-associated virus carrying miR-98 inhibitor or Nedd4L overexpression plasmid was injected into DN modeled rats to explore their roles in DN. Renal tubular epithelial cell injury models (NRK-52E cells) were induced by high glucose (HG). HG-treated NRK-52E cells were transfected with miR-98 inhibitor or Nedd4L overexpression plasmid for further verification. MiR-98 was upregulated, Nedd4L was downregulated and TGF-β/Smad2/3 signaling was activated in kidney tissues of DN rats and HG-treated NRK-52E cells. miR-98 targeted Nedd4L mRNA 3'UTR. MiR-98 depletion and Nedd4L overexpression inactivated TGF-β/Smad2/3 signaling pathway, alleviated pathological damage and fibrosis, ameliorated inflammation, and depressed cell apoptosis of kidney tissues of DN rats. MiR-98 depletion and Nedd4L overexpression inactivated TGF-β/Smad2/3 signaling pathway, strengthened viability, and limited apoptosis of HG-treated renal tubular epithelial cells. Nedd4L overexpression reversed the effect of up-regulating miR-98 on DN rats and HG-treated renal tubular epithelial cells. Altogether, we find that miR-98 is upregulated in kidney tissues of DN rats, and miR-98 diminution and Nedd4L elevation attenuate renal fibrosis through inactivation of the TGF-β/Smad2/3 pathway, which provides a novel therapy for DN.

MicroRNA-98 Inhibits Hepatic Stellate Cell Activation and Attenuates Liver Fibrosis by Regulating HLF Expression

Liver fibrosis is a major endpoint of patients with chronic liver diseases. The molecular mechanisms behind liver fibrosis remain largely unknown. Many studies have indicated the role of microRNA (miRNA) in hepatic tumorigenesis. But the role of miRNA in liver fibrosis is little known. Activated hepatic stellate cells (HSCs) can secret extracellular matrix proteins (ECM) and are the major contributors to liver fibrosis/cirrhosis. Here, a microarray assay of quiescent and transforming growth factor β1 (TGF-β1) activated HSCs indicated that miR-98 might play a crucial role in liver fibrosis. We found that miR-98 was significantly downregulated in activated HSCs. miR-98 overexpression inhibited HSCs activation. Furthermore, we hypothesized that miR-98 regulated hepatic leukemia factor (HLF) expression by binding to the 3′ UTR of its mRNA directly, as evidenced by luciferase reporter assay. HLF overexpression increased HSCs activation by inducing hypoxia inducible factor-1 alpha (HIF-1α) expression, resulting in the activation of TGF-β/Smad2/3 signaling pathway. Besides, low expression of miR-98 was also found in liver tissues from various fibrotic murine models, including carbon tetrachloride (CCl₄), bile duct ligation (BDL), and high-fat diet (HFD)-induced liver fibrosis. miR-98 overexpression in vivo by ago-miR-98 injection could attenuate CCl₄-, BDL-, and HFD-induced murine hepatic fibrosis. Meanwhile, miR-98 overexpression suppressed HLF expression and reduced fibrosis marker expression. Collectively, our study demonstrates that miR-98 suppress HSCs activation by targeting HLF directly and interacting with HIF-1α/TGF-β/Smad2/3 signaling pathway, which may be an effective therapeutic target for liver fibrosis.

MicroRNA-98-5p regulates the proliferation and apoptosis of A549 cells by targeting MAP4K3

Non-small cell lung cancer (NSCLC) is a primary subtype of lung cancer that is accompanied by a high incidence rate and poor prognosis. The primary treatment for NSCLC is chemotherapy, which has low effectiveness and high toxicity. Thus, novel targeted therapy has drawn much attention in recent years. MicroRNAs (miRs) serve important roles in multiple cancer types. In the current study, a decrease in miR-98-5p and an increase in mitogen-activated protein kinase kinase kinase kinase 3 (MAP4K3) was observed in NSCLC tumor tissues compared with normal tissues. miR-98-5p was predicted to target positions 1,056-1,063 of the MAP4K3 3'-untranslated region (UTR). The binding sites between miR-98-5p and the 3'-UTR of MAP4K3 messenger RNA were supported by the results of a dual-luciferase reporter assay. Compared with the control and miR-negative control (NC) groups, miR-98-5p mimic significantly reduced cell proliferation and increased apoptosis in NSCLC cells. In addition, miR-98-5p mimic reduced the expression of MAP4K3 and mammalian target of rapamycin while increasing the expression of cleaved caspase-3 compared with the control group and miR-NC groups. In conclusion, miR-98-5p may inhibit the progression of NSCLC via targeting of MAP4K3.

MicroRNA-98 attenuates cardiac ischemia-reperfusion injury through inhibiting DAPK1 expression

Cardiovascular ischemic disease is a large class of diseases that are harmful to human health. The significant role of microRNAs (miRNAs) in terms of controlling cardiac injury has been reported in latest studies. MiR-98 is very important in regulating the apoptosis, the differentiation, the growth as well as the metastasis of cells. Nevertheless, the effect of miR-98 in the cardiac ischemia reperfusion (I/R) injury has rarely been investigated. In the current research, we found that the miR-98 expression was down-regulated in the cardiomyocytes subjected to hypoxia/reoxygenation (H/R) and in the myocardium of the I/R rats. In addition, over-expression of miR-98 could significantly reduce the myocardial oxidative stress and ischemic injury as well as cell apoptosis. In agreement, similar findings were demonstrated in H9c2 cells subjected to H/R injury. Bioinformatic analysis using MiRanda and TargetScan and luciferase activity assay confirmed death-associated protein kinase 1 (DAPK1) as a direct target of miR-98. These findings suggest that miR-98 may be exploited as a novel molecular marker or therapeutic target for myocardial I/R injury. © 2018 IUBMB Life, 71(1):166-176, 2019.

microRNA-98 inhibits the proliferation, invasion, migration and promotes apoptosis of breast cancer cells by binding to HMGA2

Breast cancer is a major contributor leading to cancer death in females worldwide. The aim of the present study was to investigate the effects of microRNA-98 (miR-98) on the processes of cell proliferation, invasion, migration and apoptosis by binding to high-mobility group AT-hook 2 (HMGA2) in breast cancer. Breast cancer tissues and adjacent normal tissues were collected from 112 patients suffering from breast cancer. The target relationship between miR-98 and HMGA2 was verified by in connection with the bioinformatics website as well as a dual-luciferase reporter assay, both of which provided evidence indicating that HMGA2 was a target gene of miR-98. Human breast cancer MDA-MB-231 cells were treated with miR-98 mimics, miR-98 inhibitors, siRNA-HMGA2 or miR-98 inhibitors + siRNA-HMGA2. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry methods were performed to determine cell proliferation, cell cycle and apoptosis, respectively, while a Transwell assay was employed to detect cell migration and invasion. Breast cancer tissues exhibited decreased miR-98 expression, while increased expression levels of HMGA2 were recorded. The mRNA and protein expressions of HMGA2, cell proliferation, cells at the S phase, cell migration, invasion, expressions of matrix metalloproteinase (MMP)2 as well as MMP9 were all reduced in response to miR-98 mimics or siRNA-HMGA2, while a contradictory trend was observed in the miR-98 inhibitors group. In conclusion, the results of the study demonstrate that miR-98 inhibits cell proliferation, migration and invasion, while acting to promote apoptosis by negatively regulating HMGA2 in breast cancer.

MicroRNA-98 acts as a tumor suppressor in hepatocellular carcinoma via targeting SALL4. Oncotarget. 2016;7:74059-74073. [PMID: 27677076 PMCID: PMC5342035 DOI: 10.18632/oncotarget.12190]

MicroRNAs (miRs) are involved in the development and progression of hepatocellular carcinoma (HCC), but the regulatory mechanism of miR-98 in HCC still remains unclear. Here we found that miR-98 was significantly downregulated in HCC tissues compared to matched adjacent normal tissues (ANTs). Low miR-98 expression was associated with tumor size, metastasis, portal vein tumor embolus, and poor overall survival. Ectopic expression of miR-98 decreased the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of HCC cells. SALL4 was identified as a novel target of miR-98, and the protein expression of SALL4 was inhibited by miR-98 in HCC cells. Overexpression of SALL4 reversed the suppressive effects of miR-98 on the malignant phenotypes of HCC cells. Besides, SALL4, upregulated in HCC tissues compared to the matched ANTs, was inversely correlated to the miR-98 levels in HCC tissues. In addition, overexpression of miR-98 markedly suppressed the tumor growth as well as tumor-induced death in nude mice. In summary, miR-98 plays a suppressive role in the proliferation, migration, invasion and EMT of HCC cells, partly at least, via directly inhibition of SALL4. Therefore, the miR-98/SALL4 axis may become a promising therapeutic target for HCC.

MiR-98 Promotes Apoptosis of Glioma Cells via Suppressing IKBKE/NF-κB Pathway

The inhibitor of kappa B kinase epsilon is overexpressed in glioma and plays antiapoptotic role via activating nuclear factor-kappa B. microRNA-98 can suppress glioma, modulate the activities of nuclear factor-kappa B, and bind to the 3′-untranslated region of inhibitor of kappa B kinase epsilon messenger RNA. This study was aimed to investigate the modulation of inhibitor of kappa B kinase epsilon/nuclear factor-kappa B by microRNA-98 in glioma. The results indicated that microRNA-98 was downregulated in glioma cell lines and human glioma tissues. Overexpression of microRNA-98 in U87MG and T98G glioma cells significantly increased the apoptosis induced by ultraviolet irradiation and suppressed nuclear factor-kappa B luciferase activity, nuclear factor-kappa B p50 subunit expression, and B-cell lymphoma-2 (Bcl-2) expression in glioma cells. Silencing inhibitor of kappa B kinase epsilon decreased the expression of nuclear factor-kappa B p50 subunit and the luciferase activity of nuclear factor-kappa B, while the nuclear factor-kappa B activity could be significantly retrieved when inhibitor of kappa B kinase epsilon was expressed in microRNA-98-transfected cells. These findings indicated that microRNA-98 could promote apoptosis of glioma cells via inhibiting inhibitor of kappa B kinase epsilon/nuclear factor-kappa B signaling and presented a novel regulatory pathway of microRNA-98 by direct suppression of inhibitor of kappa B kinase epsilon/nuclear factor-kappa B expression in glioma cells.

MicroRNA-98 rescues proliferation and alleviates ox-LDL-induced apoptosis in HUVECs by targeting LOX-1

Oxidized low-density lipoprotein (ox-LDL) is a major and critical mediator of atherosclerosis, and the underlying mechanism is thought to involve the ox-LDL-induced dysfunction of endothelial cells (ECs). MicroRNAs (miRNAs), which are a group of small non-coding RNA molecules that post-transcriptionally regulate the expression of target genes, have been associated with diverse cellular functions and the pathogenesis of various diseases, including atherosclerosis. miRNA-98 (miR-98) has been demonstrated to be involved in the regulation of cellular apoptosis; however, the role of miR-98 in ox-LDL-induced dysfunction of ECs and atherosclerosis has yet to be elucidated. Therefore, the present study aimed to investigate the role of miR-98 in ox-LDL-induced dysfunction of ECs and the underlying mechanism. It was demonstrated that miR-98 expression was markedly downregulated in ox-LDL-treated human umbilical vein ECs (HUVECs) and that miR-98 promoted the proliferation and alleviated apoptosis of HUVECs exposed to ox-LDL. In addition, the results demonstrated that lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) was a direct target of miR-98 in HUVECs, as indicated by a luciferase assay. The results of the present study suggested that miR-98 may inhibit the uptake of toxic ox-LDL, maintain HUVEC proliferation and protect HUVECs against apoptosis via the suppression of LOX-1.

MicroRNA-98 regulates osteogenic differentiation of human bone mesenchymal stromal cells by targeting BMP2

To study the effects of microRNA‐98 (miR‐98) on human bone mesenchymal stromal cells (hBMSCs). The patients undergoing hip arthroplasty were selected by inclusion/exclusion criteria for this study. The extracted hBMSCs were detected of osteogenic differentiation by alizarin red S staining, and of cell phenotype by flow cytometry. Bioinformatics, dual luciferase report, western blotting, RT‐PCR and immunoblotting were used in our study. The hBMSCs were divided into miR‐98 mimics, miR‐98 negative control (NC), miR‐98 inhibitors, Mock and miR‐98 inhibitors + siBMP2 groups. Human bone mesenchymal stromal cells were extracted and purified in vitro and had specific cytological morphology, surface markers and abilities of self‐renewal and differentiation. Compared with the NC group and Mock group, the miR‐98 mimics group showed increased miR‐98 level while the miR‐98 inhibitors group decreased miR‐98 level (both P < 0.01). Dual luciferase reporter showed BMP2 was the target gene of miR‐98. The levels of mRNA and protein expression of BMP2, protein expression of RUNX2, alkaline phosphatase activity and osteocalcin content significantly decreased in the miR‐98 mimics group while increased in the miR‐98 inhibitors group and showed no changes in the NC group and Mock group (all P < 0.05). The miR‐98 mimics group showed obviously declined stained red particles and the miR‐98 inhibitors group showed opposite result. After lowering the expression of miR‐98, osteogenic differentiation ability of hBMSCs rose, which was weakened by the transfection with siBMP2. miR‐98 may regulate osteogenic differentiation of hBMSCs by targeting BMP2.

MiR-98 promotes chondrocyte apoptosis by decreasing Bcl-2 expression in a rat model of osteoarthritis

Altered expression of miRNA-98 (miR-98) has been reported in osteoarthritis (OA) patients, while its role and underlying mechanisms remain elusive. In the present study, a rat model of OA was established using modified Hulth method, and the expression level of miR-98 and its effect on cartilage degradation and cell apoptosis in OA rats were examined. The results showed that up-regulated miR-98 was observed in OA rats, and knockdown of miR-98 in OA rats resulted in an inhibitory effect on cartilage degradation and chondrocyte apoptosis. Then the potential apoptosis associated genes regulated by miR-98 were screened and examined in cartilage tissues. The target gene of miR-98 was validated by luciferase reporter assay. The data showed that the increased miR-98 was accompanied with a reduced expression of Bcl-2 at both mRNA and protein levels. Furthermore, the silencing of miR-98 in OA rats prevented the down-regulation of Bcl-2 in cartilage tissues. Finally, the luciferase reporter assay validated that Bcl-2 was the target gene of miR-98. In this study, we found that miR-98 might promote chondrocyte apoptosis and cartilage degradation by down-regulating Bcl-2 expression in the pathogenesis of OA, suggesting that miR-98 can be a potential target for the treatment of OA.

[microRNA-98 and microRNA-143 in nasal and paranasal sinus carcinomas and its clinical significance]

Objective:To investigate the role and clinical significance of the expression of microRNA-98(miRNA-98)and microRNA-143(miRNA-143)in development and progression of nasal and paranasal sinus carcinomas.Method:The expression miRNA-98 and miRNA-143 was detected by Real time PCR metheod in the 53 nasal and paranasal sinus carcinomas and 50 nasal polyp tissues and 20 cases of normal muscosa.The expression of miRNA-98 was analyzed in nasal and paranasal sinus carcinomas with different clinicopathogical parameters.Result:The expression of miRNA-98 in nasal and paranasal sinus carcinomas was obvious higher than that in inflammation of the nasal polyp tissues and normal muscosa,which had statistical significant difference(P<0.05).There was a positive correlation between miRNA-98 expression and TNM staging ,lymph node metastasis;but not pathological grade.The expression of miRNA-143 in nasal and paranasal sinus carcinomas was obvious lower than that in nasal polyp tissues and normal muscosa,which had statistical significant difference(P<0.05).Conculusion:miRNA-98 highly expressed in nasal and paranasal sinus carcinomas,miRNA-143 lowly expressed in nasal and paranasal sinus carcinomas.