Effects of nicotine on microRNA-124 expression in bile duct ligation-induced liver fibrosis in rats

BACKGROUND

Nicotine, the main compound of smoking may exert its effects by changing the expression of microRNAs (miRNAs). This study was conducted to further investigate the molecular mechanisms of miRNA-dependent effects of nicotine in an animal model of liver fibrosis.

METHODS

The bile duct ligation (BDL) approach was used to create a model of liver fibrosis. Twenty-four male Wistar rats were used in the study. The effects of nicotine administration on miRNA-124 expression, as well as alpha-smooth muscle actin (liver fibrosis marker) and chemokine ligand 2 (an inflammatory chemokine), were investigated using RT-qPCR. In addition, the mRNA and protein expression of signal transducer and activator of transcription 3 (STAT-3; as a potential target for miRNA-124) were investigated by RT-qPCR and immunofluorescence, respectively. Liver enzyme activity levels were measured using a colorimetric assay. In addition, the effects of nicotine on the process of liver fibrosis were investigated with histological studies.

RESULTS

The development of liver fibrosis in BDL rats and nicotine administration led to a decrease in miRNA-124 expression. The decrease in the expression is accompanied by the increase in the expression of fibrotic and proinflammatory genes. Also, an increase in STAT-3 mRNA and protein expression was observed in the fibrotic rats that received nicotine. In addition, the significant increase in bilirubin and liver enzymes in fibrotic rats worsens with nicotine administration. The results of histological studies also confirm these results.

CONCLUSION

Considering that miRNA-124 is an anti-inflammatory miRNA, it can be concluded that the decrease in its expression due to nicotine exposure leads to an increase in inflammatory processes and subsequently to an increase in liver fibrosis.

MicroRNA-124 conducts neuroprotective effect via inhibiting AK4/ATF3 after subarachnoid hemorrhage

Spontaneous subarachnoid hemorrhage (SAH) accounts for approximately 5% of all cases of stroke. SAH is correlated with elevated rates of mortality and disability. Despite significant advancements in comprehending the pathogenesis and surgical management, efficacious clinical interventions remain restricted, and the prognosis is yet to be enhanced. MicroRNAs play a crucial role in various pathological processes in organisms. Revealing these regulatory processes is conducive to the development of new treatment methods. MicroRNA-124 is highly expressed in the nervous system and has significant research value for SAH. This study aims to explore the role of miR-124 in the early post-SAH period on neural function and verify whether it is involved in the pathological and physiological processes of SAH. In this study, we used methods such as comparing the expression levels of miR-124 in cerebrospinal fluid, establishing a rat SAH model, and a mouse embryonic primary neuron hemoglobin stimulation model to verify the downstream proteins of miR-124 in SAH. Through transfection techniques, we adjusted the expression of this small RNA in Vitro and in Vivo models using miR-124 inhibitor and mimic in the primary neuron hemoglobin stimulation model and rat SAH model, and observed the phenotype. Finally, by consulting the literature and verifying in Vivo and in Vitro methods, AK4 and downstream molecule ATF3 were identified as downstream targets of miR-124.

MicroRNA-124 modulates neuroinflammation in acute methanol poisoning rats via targeting Krüppel-like factor-6

Microglia activation-stimulated neuroinflammation exerts functionally in neurodegenerative diseases like brain injury. Acute methanol poisoning (AMP) is a crucial cause of death and morbidity that possibly leads to neuroinflammation. Studies have manifested that miRNAs can modulate microglia activation to mediate neuroinflammation. Nevertheless, the role of miR-124 in AMP-stimulated neuroinflammation is uncertain. This research was to explore the action of miR-124 in AMP-stimulated neuroinflammation and its molecular mechanism. The study findings indicated that AMP accelerated microglia activation and stimulated inflammation and oxidative stress in brain tissue of rats. MiR-124 expression was lowered in AMP rats, while KLF6 expression was elevated. Elevated miR-124 or repressed KLF6 increased the number of CD206⁺ cells and decreased the number of CD68⁺ cells, as well as restrained inflammation and NF-κB phosphorylation and induced superoxide dismutase, Nrf2/HO-1, and M2 polarization. MiR-124 modulated microglia activation via targeting KLF6. AMP repressed neuronal viability and enhanced neuronal apoptosis. Suppression of miR-124 further promoted AMP-induced damage to neurons, while inhibition of KLF6 turned around this phenomenon. Anyway, our study demonstrated that miR-124 accelerates M2 polarization via targeting KLF6 to ameliorate AMP-stimulated neuronal damage.

The Effect and Potential Mechanism of microRNA-124 on the Biological Behavior of Colon Cancer Cells

OBJECTIVE

We aimed to investigate the expression of microRNA-124 (miR-124) in colon cancer and its biological function in colon cancer cells as well as its underlying mechanism.

METHODS

Mimic miR-124 and unrelated sequence were transfected into colon cancer HT29 cells, and a blank control group was established with untreated HT29 cells. The expression of miR-124 in each group was detected by qRT-PCR. CCK-8 assay, cell scratch assay, Transwell assay, and flow cytometry were used to detect the effects of miR-124 on cell growth, invasion, migration, and apoptosis in HT29 cells. The expression of TET protein family and related protein was evaluated by Western blot.

RESULTS

miR-124 expression was significantly downregulated in colon cancer HT29 cells (P<0.05). Overexpressed miR-124 suppressed cell proliferation, migration, and invasion, and it promoted the apoptosis of HT29 cells. The significantly increased expression of TET family protein and the reduction of vimentin and MMP2 expression were seen in miR-124-transfected HT29 cells (all P<0.05).

CONCLUSION

The expression of miR-124 inhibited cell proliferation, suppressed tumor cell migration and invasion, and enhanced apoptosis by its regulation of the expression of TET1, TET2, vimentin, and MMP-2 in colon cancer HT29 cells.

A paclitaxel and microRNA-124 coloaded stepped cleavable nanosystem against triple negative breast cancer

Background

Triple negative breast cancer (TNBC) is one of the most biologically aggressive breast cancers and lacks effective treatment options, resulting in a poor prognosis. Therefore, studies aiming to explore new therapeutic strategies for advanced TNBC are urgently needed. According to recent studies, microRNA-124 (miR124) not only inhibits tumour growth but also increases the sensitivity of TNBC to paclitaxel (PTX), suggesting that a platform combining PTX and miR124 may be an advanced solution for TNBC.

Results

Herein, we constructed a stepped cleavable calcium phosphate composite lipid nanosystem (CaP/LNS) to codeliver PTX and miR124 (PTX/miR124-NP). PTX/miR124-NP exhibited superior tumor microenvironment responsive ability, in which the surface PEG layer was shed in the mildly acidic environment of tumor tissues and exposed oligomeric hyaluronic acid (o-HA) facilitated the cellular uptake of CaP/LNS by targeting the CD44 receptor on the surface of tumor cells. Inside tumour cells, o-HA detached from CaP/LNS due to the reduction of disulfide bonds by glutathione (GSH) and inhibited tumour metastasis. Then, PTX and miR124 were sequentially released from CaP/LNS and exerted synergistic antitumour effects by reversing the Epithelial-Mesenchymal Transition (EMT) process in MDA-MB-231 cells. Moreover, PTX/miR124-NP showed significant antitumour efficiency and excellent safety in mice bearing MDA-MB-231 tumours.

Conclusion

Based on these results, the codelivery of PTX and miR124 by the CaP/LNS nanosystem might be a promising therapeutic strategy for TNBC.

CX3CL1/CX3CR1 axis attenuates early brain injury via promoting the delivery of exosomal microRNA-124 from neuron to microglia after subarachnoid hemorrhage

BACKGROUND

Microglial activation-mediated neuroinflammation is a major contributor to early brain injury (EBI) after subarachnoid hemorrhage (SAH). MicroRNA-124 (miR-124) is the most abundant miRNAs in the central nervous system (CNS) and plays a vital role in microglial activation by targeting protein CCAAT-enhancer-binding protein α (C/EBPα). It has been reported that the CX3CL1/CX3CR1 axis is involved in the delivery of miR-124 from neurons to microglia.

METHODS

An experimental rat SAH model was established by injecting autologous arterial blood into the prechiasmatic cistern, and cultured primary neurons and microglia were exposed to oxyhemoglobin to mimic SAH in vitro. We additionally exploited specific expression plasmids encoding CX3CL1 and CX3CR1.

RESULTS

We observed significant decreases in CX3CL1 and CX3CR1 in the brain tissues of SAH patients. We also observed decreases in the levels of CX3CL1 in neurons and CX3CR1 in microglia after SAH in rats. Moreover, microglia exhibited an activated phenotype with macrophage-like morphology and high levels of CD45 and major histocompatibility complex (MHC) class II after SAH. After overexpression of CX3CL1/CX3CR1, the level of CD45 and MHC class II and the release of inflammatory factors tumor necrosis factor α, interleukin 1α and complement 1q were significantly decreased. There was also increased neuronal degeneration and behavior dysfunction after SAH, both of which were inhibited by CX3CL1/CX3CR1 overexpression. Additionally, we found that the delivery of exosomal miR-124 from neurons to microglia was significantly reduced after SAH, accompanied by an increase in C/EBPα expression, and was inhibited by CX3CL1/CX3CR1 overexpression. In conclusion, the CX3CL1/CX3CR1 axis may play protective roles after SAH by promoting the delivery of exosomal miR-124 to microglia and attenuate microglial activation and neuroinflammation.

CONCLUSIONS

CX3CL1/CX3CR1 axis may be a potential intervention target for the inhibition of SAH-induced EBI by promoting exosome transport of miR-124 to microglia.

Baicalin suppresses renal fibrosis through microRNA-124/TLR4/NF-κB axis in streptozotocin-induced diabetic nephropathy mice and high glucose-treated human proximal tubule epithelial cells

Renal fibrosis is a major pathological event in the development of diabetic nephropathy (DN). Baicalin is a flavonoid glycoside that possesses multiple pharmacological properties including anti-fibrotic activity. In the present study, the effects of baicalin on renal fibrosis along with related molecular basis were investigated in streptozotocin (STZ)-induced DN mouse model and high glucose (HG)-treated HK-2 human proximal tubule epithelial cell model. Renal injury was evaluated through blood urea nitrogen (BUN) and serum creatinine (Scr) levels and urine albumin creatine ratio (ACR). Renal fibrosis was assessed by type IV collagen (COLIV) and fibronectin (FN) protein expression and histopathologic analysis via Masson trichrome staining. Protein levels of COLIV, FN, NF-κB inhibitor alpha (IκBα), phosphorylated IκBα (p-IκBα), p65, phosphorylated p65 (p-p65), and toll-like receptor 4 (TLR4) were measured by western blot assay. MicroRNA-124 (miR-124) and TLR4 mRNA levels were detected by RT-qPCR assay. The interaction of miR-124 and TLR4 was examined by bioinformatics analysis, luciferase reporter assay, and RIP assay. Baicalin or miR-124 attenuated renal injury and fibrosis in STZ-induced DN mice. Baicalin inhibited the increase of COLIV and FN expression induced by HG through upregulating miR-124 in HK-2 cells. TLR4 was a target of miR-124. MiR-124 inhibited TLR4/NF-κB pathway activation and the inactivation of the NF-κB pathway hindered COLIV and FN expression in HG-stimulated HK-2 cells. Baicalin prevented renal fibrosis by increasing miR-124 and inactivating downstream TLR4/NF-κB pathway in DN, hinting the pivotal values of baicalin and miR-124 in the management of DN and renal fibrosis.

Interfering cellular lactate homeostasis overcomes Taxol resistance of breast cancer cells through the microRNA-124-mediated lactate transporter (MCT1) inhibition

Background

Breast cancer, the most common invasive cancer of women, is a malignant neoplasm and the second main cause of cancer death. Resistance to paclitaxel (Taxol), one of the frequently used chemotherapy agents for breast cancer, presents a major clinical challenge. Recent studies revealed that metabolic alterations of cancer cells play important roles in chemo-resistance.

Materials and methods

In this study, Human breast cancer cells, BT474, SKBR3 and MCF7 were used to study the causal relationship between the lactate exporter, MCT1 (SLC16A1)-modulated glucose metabolism and Taxol resistance of breast cancer cells. Taxol resistant breast cancer cells were established. The intracellular lactate and extracellular lactate levels as well glucose uptake and oxygen consumption were measured. MicroRNA-124 expressions were detected by qRT-PCR from both breast cancer patient samples and breast cancer cells. Target of miR-124 was predicted and verified by Western blot and luciferase assay. An xenograft mice model was established and evaluated for the in vivo tumor therapeutic effects of MCT1 inhibitor plus microRNA-124 treatments.

Results

Low toxic Taxol treatments promoted cellular glucose metabolism and intracellular lactate accumulation with upregulated lactate dehydrogenase-A (LDHA) and MCT1 expressions. By establishing Taxol resistant breast cancer cell line, we found Taxol resistant cells exhibit upregulated LDHA and MCT1 expressions. Furthermore, glucose consumption, lactate production and intracellular ATP were elevated in Taxol resistant MCF7 cells compared with their parental cells. The miR-124, a tumor suppressive miRNA, was significantly downregulated in Taxol resistant cells. Luciferase assay and q-RT-PCR showed MCT1 is a direct target of miR-124 in both breast cancer cell lines and patient specimens. Moreover, co-treatment of breast cancer cells with either MCT1 inhibitor or miR-124 plus Taxol led to synergistically cytotoxic effects. Importantly, based on in vitro and in vivo results, inhibition of MCT1 significantly sensitized Taxol resistant cells. Finally, rescue experiments showed restoration of MCT1 in miR-124 overexpressing cells promoted Taxol resistance.

Conclusions

This study reveals a possible role of miRNA-214-mediated Taxol resistance, contributing to identify novel therapeutic targets against chemoresistant breast cancers.

MicroRNA-124 Enhances Dopamine Receptor Expression and Neuronal Proliferation in Mouse Models of Parkinson's Disease via the Hedgehog Signaling Pathway by Targeting EDN2

Recent studies have elaborated on the concept that a number of microRNAs (miRNAs) have a potential effect on the pathogenesis and development of Parkinson's disease (PD). PD is recognized as a common progressive bradykinetic disorder that results from the death of dopaminergic neurons in the substantia nigra. The purpose of this study was to explore whether microRNA-124 (miR-124) affected dopamine receptor (DAR) expression and neuronal proliferation and apoptosis in the 1-methyl-4-pheny-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse models of PD. The targeting relationship of miR-124 and EDN2 was confirmed through bioinformatic predictions and dual-luciferase reporter assay. The expression of miR-124 and EDN2 was altered to assess their effect on the expression of DAR in the substantia nigra and isolated neurons, as well as the neuronal proliferation and apoptosis rate. The obtained results implied that the treatments of miR-124 mimic and si-EDN2 resulted in elevated expressions of Glil, SHH, PTCH1, DAT, DRD1, and DRD2. However, these treatments facilitated neuronal proliferation and suppressed neuronal apoptosis, corresponding to reduced expression of caspase-3 and Bax, as well as increased levels of Bcl-2 expression. These results were discovered to be achieved through the activation of the Hedgehog signaling pathway. With this taken into account, our study demonstrated that miR-124 overexpression promoted DAR expression and neuronal proliferation and suppressed neuronal apoptosis by downregulating EDN2 via activating the Hedgehog signaling pathway.

MicroRNA-124 Prevents H2O2-Induced Apoptosis and Oxidative Stress in Human Lens Epithelial Cells via Inhibition of the NF-κB Signaling Pathway

AIM

To investigate the regulation of microRNA-124 -(miRNA-124) on NF-κB pathway from H2O2-induced apoptosis and oxidative stress in human lens epithelial cells (hLEC).

METHODS

The MTT (3-[4, 5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay was used to detect hLEC -viability. HLECs were divided into Blank, H2O2, mimics (miRNA-124 mimics) + H2O2, NC+ H2O2, pyrrolidine dithiocarbamate (PDTC; NF-κB signaling pathway inhibitor) + H2O2, and inhibitors (miRNA-124 inhibitors) + PDTC + H2O2 groups. Quantitative real-time polymerase chain reaction and Western blot were employed to detect mRNA and protein expressions, Dichloro-dihydro-fluorescein diacetate to measure reactive oxygen species (ROS) production, and AnnexinV-FITC/PI staining to determine cell apoptosis. The mitochondrial membrane potential (MMP) was detected by fluorescence probe JC-1.

RESULTS

The H2O2-induced hLEC showed reductions in cell viability with decreased miRNA-124 but increased p-p65 in a dose-/time-dependent manner. Furthermore, ROS production, malondialdehyde content, Bax and Caspase-3 expressions, and cell apoptosis were elevated in H2O2-induced hLEC, whereas the activities of superoxide dismutase and glutathione peroxidase, Bcl-2 expression, MMP, as well as the mitochondrial energy metabolism genes were reduced. Additionally, miRNA-124 mimics and PDTC both decreased the p-p65 and reversed the cytotoxicity in H2O2-induced hLEC.

CONCLUSION

MiRNA-124 prevents H2O2-induced oxidative stress and apoptosis in hLEC through suppressing the activation of the NF-κB pathway.

MicroRNA-124 regulates the expression of MEKK3 in the inflammatory pathogenesis of Parkinson's disease

Background

Parkinson’s disease (PD) is the most prevalent neurodegenerative disorder that is characterised by selective loss of midbrain dopaminergic (DA) neurons. Chronic inflammation of the central nervous system is mediated by microglial cells and plays a critical role in the pathological progression of PD. Brain-specific microRNA-124 (miR-124) expression is significantly downregulated in lipopolysaccharide (LPS)-treated BV2 cells and in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD. However, whether abnormal miR-124 expression could regulate the activation of microglia remains poorly understood.

Methods

BV2 cells were activated by exposure to LPS, and the expression levels of miR-124, mitogen-activated protein kinase kinase kinase 3 (MEKK3), and the nuclear factor of kappaB (NF-κB) p-p65 were analysed. Over-expression and knockdown studies of miR-124 were performed to observe the effects on MEKK3/NF-κB signalling pathways, and the induction of pro-inflammatory and neurotoxic factors was assessed. In addition, a luciferase reporter assay was conducted to confirm whether MEKK3 is a direct target of miR-124. Meanwhile, production of miR-124, MEKK3, and p-p65; midbrain DA neuronal death; or activation of microglia were analysed when treated with or without miR-124 in the MPTP-induced model of PD.

Results

We found that the knockdown of MEKK3 could inhibit the activation of microglia by regulating NF-κB expression. Over-expression of miR-124 could effectively attenuate the LPS-induced expression of pro-inflammatory cytokines and promote the secretion of neuroprotective factors. We also first identified a unique role of miR-124 in mediating the microglial inflammatory response by targeting MEKK3/NF-κB signalling pathways. In the microglial culture supernatant (MCS) transfer model, over-expression of the miR-124 or knockdown of MEKK3 in BV2 cells prevented SH-SY5Y from apoptosis and death. Moreover, MEKK3 and p-p65 were abundantly expressed in the midbrain. Furthermore, their expression levels increased and microglial activation was observed in the MPTP-induced model of PD. In addition, exogenous delivery of miR-124 could suppress MEKK3 and p-p65 expression and attenuate the activation of microglia in the substantia nigra pars compacta of MPTP-treated mice. miR-124 also could prevent MPTP-dependent apoptotic midbrain DA cell death in a MPTP-induced PD model.

Conclusions

Taken together, our data suggest that miR-124 can inhibit neuroinflammation in the development of PD by regulating the MEKK3/NF-κB signalling pathways and implicate miR-124 as a potential therapeutic target for regulating the inflammatory response in PD.

A MicroRNA-124 Polymorphism is Associated with Fracture Healing via Modulating BMP6 Expression

BACKGROUND

miR-124-3p has been reported to be involved in the pathogenesis of many diseases by modulating a variety of signaling pathways. In this study, we aimed to understand the impact of miR-124-3p expression level on the fracture healing in the patients of metaphyseal fracture of distal tibia, who received minimal invasive percutaneous plate osteosynthesis.

METHODS

We firstly collected 195 patients of metaphyseal fracture of distal tibia, and the genotype of rs531564 was determined: GG (n=124) and GC+CC (n=71). We collected information of the participants including age, gender, total in-hospital time, smoking and alcohol consumption. Subsequently, we searched the miRNA database online to identify the possible binding sequence of miR-124-3p located within the 3'-UTR of the target gene. We did correlation analysis and luciferase to understand the regulatory relationship between miR-124-3p and BMP6. Meanwhile, we also conducted real time PCR and western blotting analysis to study the mRNA and protein expression level of BMP6 in different genotype groups. We then treated the cells with scramble control, miR-124-3p mimics, BMP6 siRNA and miR-124-3p inhibitors to investigate the influence of miR-124-3p on the expression of BMP6, viability and apoptosis of cells.

RESULTS

Total in-hospital time was significantly longer in GC+CC group than GG group. MiR-124-3p was up-regulated in GG group than GC and CC groups. BMP6 was virtual target of miR-124-3p. There existed negative regulatory relationship betweenmiR-124-3p and BMP6. The mRNA and protein expression level of BMP6 decreased in GG group. MiR-124-3p decreased the expression of BMP6. MiR-124-3p negatively interfered with the viability of cells and BMP6 positively interfered with the viability of cells. MiR-124-3p reduced apoptosis and BMP6 promoted apoptosis.

CONCLUSION

These data proved the expression of miR-124-3p was associated with the healing of metaphyseal fracture of distal tibia, and could be recognized as a biomarker to predict the healing of metaphyseal fracture of distal tibia.

MicroRNA-124 upregulation inhibits proliferation and invasion of osteosarcoma cells by targeting sphingosine kinase 1

Increasing evidence has confirmed that the dysregulation of microRNAs (miRNAs) contributes to the proliferation and invasion of human cancers. Previous studies have shown that the dysregulation of miR-124 is in numerous cancers. However, the roles of miR-124 in human osteosarcoma (OS) have not been well clarified. Therefore, this study was to investigate the biological functions and molecular mechanisms of miR-124 in OS cell lines, discussing whether it could be a therapeutic biomarker of OS in the future. In this study, our results demonstrated that miR-124 was down-regulated in OS cell lines and tissues. Furthermore, the low level of miR-124 was associated with increased expression of Sphingosine kinase 1 (SPHK1) in OS cells and tissues. Up-regulation of miR-124 significantly inhibited cell proliferation, invasion, and MMP-2 and -9 expressions of OS cells. Bioinformatics analysis predicted that the SPHK1 was a potential target of miR-124. Further study by luciferase reporter assay demonstrated that miR-124 could directly target SPHK1. Overexpression of SPHK1 in OS cells transfected with miR-124 mimic partially reversed the inhibitory of miR-124. In conclusion, miR-124 inhibited cell proliferation and invasion in OS cells by downregulation of SPHK1, and that downregulation of SPHK1 was essential for the miR-124-inhibited cell invasion and in OS cells.

Nicotine protects against DSS colitis through regulating microRNA-124 and STAT3

Although it is generally believed that nicotine accounts for the beneficial effect of smoking on ulcerative colitis, the underlying mechanisms remain not well understood. Our previous finding that nicotine inhibits inflammatory responses through inducing miR-124 prompted us to ask whether the miRNA is involved in the protective action of nicotine against UC. Our present study found that miR-124 expression is upregulated in colon tissues from UC patients and DSS colitis mice. Nicotine treatment further augmented miR-124 expression in lymphocytes isolated from human ulcerative colonic mucosa and ulcerative colon tissues from DSS mice, both in infiltrated lymphocytes and epithelial cells. Moreover, knockdown of miR-124 significantly diminished the beneficial effect of nicotine on murine colitis and IL-6-treated Caco-2 colon epithelial cells. Further analysis indicated that nicotine inhibited STAT3 activation in vivo and in IL-6 treated Caco-2 cells and Jurkat human T lymphocytes, in which miR-124 knockdown led to increased activation of STAT3. Blocking STAT3 activity alone is beneficial for DSS colitis and also abolished nicotine's protective effect in this model. These data indicate that nicotine exerts its protective action in UC through inducing miR-124 and inhibiting STAT3, and suggest that the miR-124/STAT3 system is a potential target for the therapeutic intervention of UC.

KEY MESSAGE

Nicotine upregulates miR-124 expression in ulcerative colon tissues and cells. MiR-124 is required for the protective role of nicotine in DSS colitis mice and epithelial cells. The protective effect of nicotine in murine DSS colitis depends on blocking STAT3 activation. MiR-124 mediates the inhibitory role of nicotine on STAT3/p-STAT3. Targeting miR-124 and STAT3 represents a novel approach for treating ulcerative colitis.

Combined Effect of Metastasis-Related MicroRNA, miR-34 and miR-124 Family, Methylation on Prognosis of Non-Small-Cell Lung Cancer

BACKGROUND

Many patients with non-small-cell lung cancer (NSCLC) still develop tumor metastasis and recurrence after pulmonary resection and are the primary causes of lung cancer treatment failure and death. MicroRNAs (miRs) have central roles during tumor metastasis and many miR genes are potentially subjected to control by DNA methylation in multiple tumor types. Recently, miR-34 and miR-124 have been demonstrated as potential regulators of the metastasis process in several cancer types.

MATERIALS AND METHODS

We studied the methylation status of miR-34 and miR-124 families in 157 patients with NSCLC using methylation-specific polymerase chain reaction and evaluated the clinical effect of their methylation on the patients' prognosis.

RESULTS

Methylation was detected in 30.6% for miR-34a, 40.8% for miR-34b/c, 30.6% for miR-124-1, 49.7% for miR-124-2, and 51.6% for miR-124-3 in NSCLC tissue. miR-34b/c methylation was significantly associated with age, gender, smoking status, histologic type, and pathologic stage. miR-34b/c, miR-124-2, and miR-124-3 methylation were significantly associated with worse survival in all patients (adjusted hazard ratio [HR_adj] for miR-34b/c, 3.34; 95% confidence interval [CI], 1.95-5.74; P < .0001; HR_adj for miR-124-2, 1.99; 95% CI, 1.19-3.32; P = .009; and HR_adj for miR-124-3, 2.10; 95% CI, 1.24-3.55; P = .006). When miR-34b/c and miR-124-3 methylation were combined, overall survival decreased as the number of methylations increased (P_trend < .0001).

CONCLUSION

These findings suggest that miR-34 and miR-124 loci methylation could be a tumor-associated frequent event during NSCLC tumorigenesis and could be used as powerful markers for the prognosis of patients with NSCLC.

Paeoniflorin inhibits human gastric carcinoma cell proliferation through up-regulation of microRNA-124 and suppression of PI3K/Akt and STAT3 signaling

AIM: To examine the potential anti-tumor activity of paeoniflorin in the human gastric carcinoma cell line MGC-803.

METHODS: Cell viability and cytotoxic effects in MGC-803 cells were analyzed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assay, respectively. Cell apoptosis of MGC-803 cells was measured using flow cytometry, DAPI staining assay and caspase-3 activity assay. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression of microRNA-124 (miR-124) in response to paeoniflorin. The expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), phospho-Akt (p-Akt) and phospho-signal transducer and activator of transcription 3 (p-STAT3) were also measured by quantitative RT-PCR and Western blot analysis in normal, miR-124 and anti-miR-124 over-expressing MGC-803 cells, treated with paeoniflorin.

RESULTS: Paeoniflorin was found to inhibit MGC-803 cell viability in a dose-dependent manner. Paeoniflorin treatment was associated with the induction of apoptosis and caspase-3 activity in MGC-803 cells. Paeoniflorin treatment significantly increased miR-124 levels and inhibited the expression of PI3K, Akt, p-Akt and p-STAT3 in MGC-803 cells. Interestingly, the over-expression of miR-124 inhibits PI3K/Akt and phospho-STAT3 expressions in MGC-803 cells. PI3K agonist (IGF-1, 1 μg/10 μL) or over-expression of STAT3 reversed the effect of paeoniflorin on the proliferation of MGC-803 cells. Over-expression of anti-miR-124 in MGC-803 cells reversed paeoniflorin-induced up-regulation.

CONCLUSION: In summary, the in vitro data suggest that paeoniflorin is a potential novel therapeutic agent against gastric carcinoma, which inhibits cell viability and induces apoptosis through the up-regulation of miR-124 and suppression of PI3K/Akt and STAT3 signaling.

MicroRNA-124 targets CCNA2 and regulates cell cycle in STHdh(Q111)/Hdh(Q111) cells

Mutation in huntingtin (HTT) gene causes Huntington's disease (HD). Expression of many micro RNAs is known to alter in cell, animal models and brains of HD patients, but their cellular effects are not known. Here, we show that expression of microRNA-124 (miR-124) is down regulated in HD striatal mutant STHdh(Q111)/Hdh(Q111) cells, a cell model of HD compared to STHdh(Q7)/Hdh(Q7) cells. STHdh(Q7)/Hdh(Q7) and STHdh(Q111)/Hdh(Q111) cells express endogenously full length wild type and mutant HTT respectively. We confirmed this result in R6/2 mouse, an animal model of HD, expressing mutant HTT. Gene Ontology terms related to cell cycle were enriched significantly with experimentally validated targets of miR-124. We observed that expression of Cyclin A2 (CCNA2), a putative target of miR-124 was increased in mutant STHdh(Q111)/Hdh(Q111) cells and brains of R6/2 mice. Fraction of cells in S phase was higher in asynchronously growing mutant STHdh(Q111)/Hdh(Q111) cells compared to wild type STHdh(Q7)/Hdh(Q7) cells and could be altered by exogenous expression or inhibition of miR-124. Exogenous expression or knock down of CCNA2, a target of miR-124, also alters proportion of cells in S phase of HD cell model. In summary, decreased miR-124 expression could increase CCNA2 in cell and animal model of HD and is involved in deregulation of cell cycle in STHdh(Q111)/Hdh(Q111) cells.