MicroRNA-138 promotes the progression of multiple myeloma through targeting paired PAX5.

BACKGROUND: Multiple myeloma cancer stem cells (MMSC) have been considered as the leading cause of multiple myeloma (MM) drug resistance and eventual relapse, microRNAs (miRNAs) collectively participate in the progression of MM. However, the pathogenesis of miR-138 in MMSC is still not fully understood. OBJECTIVE: The intention of this study was to investigate the mechanism and role of miR-138 in multiple myeloma. METHOD: Bone marrow samples and peripheral blood from patients and normal controls were collected. Use Magnet-based Cancer Stem Cell Isolation Kit to separate and extract MMSC. Real-time quantitative PCR (RT-qPCR) was carried out to determine mRNA level. Western blot was applied to detect protein levels. MTT and flow cytometry were conducted to examine the proliferation and apoptosis of MMSC. Finally, dual-luciferase reporter gene assays were performed to confirm that paired box 5 (PAX5) is a direct target for miR-138. RESULTS: Compared with normal group, the expression of miR-138 in patients was significantly up-regulated, and the expression of miR-138 was in a negative correlation with PAX5. Additionally, downregulated miR-138 facilitated the apoptosis and inhibited the proliferation of MMSC in vitro and in vivo. Downregulated miR-138 moderated the expression of PAX5, Bcl-2, Bax, and Caspase-3. PAX5 was a direct target of miR-138. CONCLUSION: Taken together, miR-138 plays a carcinogenic role in MM, and miR-138 adjusted the proliferation and apoptosis of MMSC by targeting PAX5. miR-138 has the probability of becoming a new medicinal target for the treatment of MM.

GRHPR, Targeted by miR-138-5p, Inhibits the Proliferation and Metastasis of Hepatocellular Carcinoma Through PI3K/AKT Signaling Pathway.

Background: Hepatocellular carcinoma (HCC) is a highly aggressive cancer. This study aims to elucidate the role of Glyoxylate reductase/hydroxypyruvate reductase (GRHPR) in HCC proliferation and metastasis, along with its molecular mechanism, and to identify miRNAs targeting GRHPR. Materials and Methods: Expression levels of GRHPR and miR-138-5p were assessed using real-time fluorescent quantitative polymerase chain reaction and Western blot techniques. Bioinformatic analysis was employed to identify miRNAs targeting GRHPR, and the results were confirmed via dual-luciferase reporter assays. HCC cell lines overexpressing GRHPR were established to investigate its roles in cell proliferation, migration, and invasion. The biological function of miR-138-5p targeting GRHPR in HCC cells was also evaluated. Furthermore, a xenograft mouse model was utilized to examine the in vivo functions of GRHPR. Results: GRHPR expression was downregulated in HCC, whereas miR-138-5p was upregulated. Overexpression of GRHPR suppressed HCC cell proliferation, migration, and invasion. Conversely, inhibition of GRHPR by miR-138-5p promoted HCC cell proliferation and invasive properties. MiR-138-5p was found to regulate Phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) phosphorylation levels by inhibiting GRHPR expression. Conclusion: This study highlights GRHPR's role as a tumor suppressor in HCC, with its function being regulated by miR-138-5p.

PDL1 targeting by miR-138-5p amplifies anti-tumor immunity and Jurkat cells survival in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) has constituted over 80% of the lung cancer population with a poor prognosis. Over the past decade, immunotherapy has been constructed in the enlargement of immune checkpoint inhibitors as a promising approach for NSCLC treatment. Evading the immune system using the PD-1/PD-L1 axis is an intelligent way for cancers, and T cells cannot respond fully and confront cancer. Recently, the miR-138 was reported as a PD-L1 regulator in NSCLC. However, its inhibitory impact on T-cell exhaustion has not been characterized. The present study aims to impair PD-L1 (B7-H1) expression in Adenocarcinoma cell lines using miR-138-5p and determines how it prevents Jurak cell exhaustion. To gain the purpose, first, 18 highly significant dysregulated miRNAs containing hsa-miR-138 and CD274-mRNA network were detected in NSCLC based on bioinformatics analysis. Moreover, our study revealed a high level of miR-138-5p could make significant changes like PDL1 downregulation, proliferation, and mortality rate in A549/Calu6 cells. We also simulate cancer environmental conditions by culturing Jurak cells and NSCLC cell lines under the influence of stimulator cytokines to show how miR-138-5p survives Jurak cells by targeting PD-L1/PD-1pathway.

Decreasing circ_0014614 promotes the differentiation of bone marrow flineage cells into megakaryocytes in essential thrombocythemia via activiation of miR-138-5p/caspase3 axis.

BACKGROUND: Circular RNAs (circRNA) are pivotal in hematological diseases. Previous study showed that circ_0014614 (circDAP3) was significantly underexpressed in bone marrow-derived exosomes from essential thrombocythemia (ET) patients, affecting the differentiation of bone marrow lineage cells into megakaryocytes. METHODS: Fluorescence in situ hybridization (FISH) was used to display circ_0014614's primary cytoplasmic location in K562 cells. Cytoscape software was used to predict the circRNA-miRNA-mRNA networks, and their expression at the cellular level was detected by Quantitative reverse transcription-polymerase chain reaction (qRT-PCR). qRT-PCR was utilized to detect the expression levels of circ_0014614，miR-138-5p and caspase3 mRNA. Western blot was used to determine the protein levels of GATA-1, RUNX-1, NF-E2, CD41 and caspase3. The proliferation of K562 cells was assessed using the Cell Counting Kit-8 (CCK-8) Assay. Furthermore, the interplay between miR-138-5p and circ_0014614 or caspase3 was elucidated through a Dual-luciferase reporter assay. RESULTS: FISH assay indicated circ_0014614's primary cytoplasmic location in K562 cells. In ET bone marrow and K562 cells, circ_0014614 and caspase3 were down-regulated, whereas miR-138-5p saw a significant surge. Overexpressing circ_0014614 curtailed K562 cells' proliferation and differentiation. Further, circ_0014614 targeted miR-138-5p, with heightened miR-138-5p levels counteracting circ_0014614's inhibition. MiR-138-5p further targeted caspase3, and caspase3 silencing neutralized suppressed miR-138-5p's effects on K562 cell differentiation. CONCLUSION: Circ_0014614 was down-regulated in ET bone marrow and bone marrow lineage cells, and upregulating circ_0014614 can inhibit bone marrow lineage cells' proliferation and differentiation into megakaryocytes. Mechanistically, circ_0014614 functioned as ceRNA via sponging miR-138-5p and alleviated the inhibitory effect of miR-138-5p on its target caspase3, which potentially deters tumor activity in ET.

Circ-Bptf Ameliorates Learning and Memory Impairments via the miR-138-5p/p62 Axis in APP/PS1 Mice.

Alzheimer's disease (AD) is a common age-associated progressive neurodegenerative disorder that is implicated in the aberrant regulation of numerous circular RNAs (circRNAs). Here, we reported that circ-Bptf, a conserved circRNA derived from the Bptf gene, showed an age-dependent decrease in the hippocampus of APP/PS1 mice. Overexpression of circ-Bptf significantly reversed dendritic spine loss and learning and memory impairment in APP/PS1 mice. Moreover, we found that circ-Bptf was predominantly localized to the cytoplasm and upregulated p62 expression by binding to miR-138-5p. Furthermore, the miR-138-5p mimics reversed the decreased expression of p62 induced by the silencing of circ-Bptf. Together, our findings suggested that circ-Bptf ameliorated learning and memory impairments via the miR-138-5p/p62 axis in APP/PS1 mice. It may act as a potential player in AD pathogenesis and therapy.

Sodium tanshinone IIA sulfonate inhibits tumor growth via miR-138 upregulation in intermittent hypoxia-induced xenograft mice.

PURPOSE: We studied the functions of sodium tanshinone IIA sulfonate (TSA) in inducing tumor growth in obstructive sleep apnea (OSA)-mimicking intermittent hypoxia (IH) xenograft mice and the underlying potential molecular mechanism. METHODS: RNA sequencing was conducted to screen the differentially expressed microRNAs in cell lines exposed to IH with or without TSA treatment. As part of the 5-week in vivo study, we treated xenograft mice with 8-h IH once daily. TSA and miR-138 inhibitors or mimics were administrated appropriately. In addition, we performed real-time quantitative polymerase chain reaction (RT-PCR), Western blotting, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), microvessel density (MVD), and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays. RESULTS: RNA sequencing and RT-PCR results demonstrated that TSA increased the levels of miR-138 under IH conditions in vitro. TSA reduced the IH-stimulated high levels of hypoxia-induced factor-1α and vascular endothelial growth factor. Furthermore, IH contributed to high tumor migration, invasion, MVD, and low apoptosis. TSA attenuated IH-mediated tumor proliferation, migration, invasion, MVD, and increased apoptosis, whereas miR-138 inhibitor interrupted the effect of TSA on treating IH-induced tumor behaviors. CONCLUSIONS: OSA mimicking IH facilitates tumor growth and reduces miR-138 levels. TSA inhibits IH-induced tumor growth by upregulating the expression of miR-138.

Suppression of ZNF205-AS1/EGR4 positive feedback loop attenuates cisplatin resistance of non-small cell lung cancer cells via targeting miR-138-5p/OCT4 pathway.

Background: Long non-coding RNAs (lncRNAs) are frequently reported to involve in the onset and development of non-small cell lung cancer (NSCLC). Cisplatin (DDP) resistance continues to pose a daunting challenge for improving the prognosis of NSCLC patients. The current study intends to elucidate the molecular mechanisms underlying the function of lncRNA ZNF205 AS1/early growth response 4 (EGR4) positive feedback loop in DDP resistance of NSCLC. Methods: A series of assays, including real-time polymerase chain reaction (PCR), western blotting, flow cytometry, and dual-luciferase reporter, were performed to evaluate the effect of ZNF205-AS1/EGR4 loop in the established DDP-resistant A549 cell line and its progenitor A549 cell line. Immunohistochemistry (IHC) technique was conducted to investigate the expression pattern of EGR4 and octamer-binding protein 4 (OCT4) in NSCLC tissues. RNA pull-down assay was carried out to evaluate the interaction between miR-138-5p and EGR4 and OCT4. Transwell assay and wound healing assay was used to evaluate the invasive and migratory potential of cells subject to various treatment. The protein levels of Bcl2, Bax, Cl-caspase 3, Cl-PARP and OCT4 were measured in western blotting assay. Results: The levels of ZNF205-AS1, EGR4 and OCT4 were notably upregulated in post-chemotherapy DDP-resistant lung specimens, as opposed to those pre-chemotherapy, and in A549/DDP cells than the progenitor DDP-sensitive A549 cells. In contrast, the level of miR-138-5p was significantly reduced in A549/DDP cells (P<0.05). Luciferase reporter assay confirmed the interaction between ZNF205-AS1 and miRNA-138-5p. Protein-RNA interaction was validated between miR-138-5p, EGR4 and OCT4. The higher chemosensitivity of DDP-resistant cells induced by the loss-of-function of ZNF205-AS1 could be diminished by a miR-138-5p inhibitor. Conclusions: Our data demonstrated that miR-138-5p/OCT4 functions as a downstream effector of the ZNF205-AS1/EGR4 positive feedback loop and mediates resistance of NSCLC cells to DDP. Our work sheds light on the therapeutic strategies for NSCLC with DDP chemoresistance.

miR-138-5p ameliorates intestinal barrier disruption caused by acute superior mesenteric vein thrombosis injury by inhibiting the NLRP3/HMGB1 axis.

Background: Acute superior mesenteric venous thrombosis (ASMVT) decreases junction-associated protein expression and intestinal epithelial cell numbers, leading to intestinal epithelial barrier disruption. Pyroptosis has also recently been found to be one of the important causes of mucosal barrier defects. However, the role and mechanism of pyroptosis in ASMVT are not fully understood. Methods: Differentially expressed microRNAs (miRNAs) in the intestinal tissues of ASMVT mice were detected by transcriptome sequencing (RNA-Seq). Gene expression levels were determined by RNA extraction and reverse transcription-quantitative PCR (RT-qPCR). Western blot and immunofluorescence staining analysis were used to analyze protein expression. H&E staining was used to observe the intestinal tissue structure. Cell Counting Kit-8 (CCK-8) and fluorescein isothiocyanate/propidine iodide (FITC/PI) were used to detect cell viability and apoptosis, respectively. Dual-luciferase reporter assays prove that miR-138-5p targets NLRP3. Results: miR-138-5p expression was downregulated in ASMVT-induced intestinal tissues. Inhibition of miR-138-5p promoted NLRP3-related pyroptosis and destroyed tight junctions between IEC-6 cells, ameliorating ASMVT injury. miR-138-5p targeted to downregulate NLRP3. Knockdown of NLRP3 reversed the inhibition of proliferation, apoptosis, and pyroptosis and the decrease in tight junction proteins caused by suppression of miR-138-5p; however, this effect was later inhibited by overexpressing HMGB1. miR-138-5p inhibited pyroptosis, promoted intestinal epithelial tight junctions and alleviated ASMVT injury-induced intestinal barrier disruption via the NLRP3/HMGB1 axis.

Kaempferol and nicotiflorin ameliorated alcohol-induced liver injury in mice by miR-138-5p/SIRT1/FXR and gut microbiota.

Aims: Excessive alcohol consumption can lead to alcoholic liver diseases (ALDs). Tetrastigma hemsleyanum Diels et Gilg is a rare Chinese medicinal herb. Tetrastigma hemsleyanum Diels et Gilg has been validated to be highly effective for treating hepatitis. Kaempferol and nicotiflorin are two highly representative flavonoids, which have exhibit therapeutic effects on liver disease. Therefore, the protective mechanism of kaempferol and nicotiflorin on alcohol-induced liver injury were investigated. Main methods: Forty mice were used in this study. After treatment of Kaempferol and nicotiflorin, serum and liver were collected and used for determination of biochemical indicators, H&E staining, and molecular detection. The interaction of miRNAs from serum extracellular vehicles (EVs) with mRNAs and 16S rRNA sequencing of gut microbiota were also investigated. Key findings: The results showed that kaempferol and nicotiflorins significantly ameliorated alcohol-induced liver damage and observably regulated gut microbiota. Specifically, the levels of malondialdehyde (MDA) and CYP2E1 in the liver significantly reduced, and the activity of superoxide dismutase (SOD) and glutathione (GSH) in the liver evidently increased. They also significantly relieved liver oxidative stress and lipid accumulation by suppressing miR-138-5p expression, inversely enhancing deacetylase silencing information regulator 2 related enzyme-1 (SIRT1) levels and then decreasing farnesoid X receptor (FXR) acetylation, which then modulated Nrf2 and SREBP-1c signaling pathways to regulate oxidative stress and lipid metabolism induced by alcohol. Significance: Kaempferol and nicotiflorin reduced alcohol-induced liver damage by enhancing alcohol metabolism and reducing oxidative stress and lipid metabolism. The intestinal microorganism disorder was also ameliorated after oral kaempferol and nicotiflorin.

Evaluation of MMP-13 and Micro RNA-138 as prognostic biomarkers for breast cancer in Egyptian women patients.

BACKGROUND: Elevated serum levels of MMP-13 are linked to tumor growth and metastasis, while miR-138 dysregulation is observed in breast cancer cases. The aim of this study is to investigate the expression of miR-138 and MMP-13 levels as potential biomarkers for the prognosis of breast cancer. PATIENTS AND METHOD: In this retrospective case-control study, 119 female subjects were recruited and divided into three groups. MMP-13 level was measured using Enzyme Linked Immunosorbent Assay (ELISA), while real-time PCR technique was employed to quantify miR-138 expression. RESULTS: Both non-metastatic and metastatic groups showed significantly higher levels of serum MMP-13 compared to other groups. MMP-13 levels are significantly increased among patients with advanced tumor size, lymph node metastasis, and triple-negative breast cancer cases. An inverse significant association between MMP-13 levels and response to treatment was observed. Expression of miR-138 underwent a significant down-regulation in breast cancer patients, and a statistically significant association was established between miR-138 expression and triple-negative breast cancer cases. A positive association was detected between the increase in miR-138 expression and the good response to treatment. The expression of miR-138 was inversely correlated with the MMP-13 levels. CONCLUSION: MMP-13 levels were significantly higher in breast cancer, especially in advanced cases, suggesting its role in promoting tumor invasion and metastasis. MiR-138 was down-regulated in breast cancer, especially in triple-negative breast cancer patients, rendering it a promising biomarker for triple-negative breast cancer. Modulation of miR-138 expression and MMP-13 levels may represent therapeutic targets for breast cancer.

MiR-138-5p Inhibits Thyroid Cancer Cell Growth and Stemness by Targeting TRPC5/Wnt/ß-Catenin Pathway.

MicroRNAs play a key role in the pathogenesis of many types of cancer, including thyroid cancer (TC). MiR-138-5p has been confirmed to be abnormally expressed in TC tissues. However, the role of miR-138-5p in TC progression and its potential molecular mechanism need to be further explored. In this study, quantitative real-time PCR was used to examine miR-138-5p and TRPC5 expression, and western blot analysis was performed to examine the protein levels of TRPC5, stemness-related markers, and Wnt pathway-related markers. Dual-luciferase reporter assay was used to assess the interaction between miR-138-5p and TRPC5. Cell proliferation, stemness, and apoptosis were examined using colony formation assay, sphere formation assay, and flow cytometry. Our data showed that miR-138-5p could target TRPC5 and its expression was negatively correlated with TRPC5 expression in TC tumor tissues. MiR-138-5p decreased proliferation, stemness, and promoted gemcitabine-induced apoptosis in TC cells, and this effect could be reversed by TRPC5 overexpression. Moreover, TRPC5 overexpression abolished the inhibitory effect of miR-138-5p on the activity of Wnt/ß-catenin pathway. In conclusion, our data showed that miR-138-5p suppressed TC cell growth and stemness via the regulation of TRPC5/Wnt/ß-catenin pathway, which provided some guidance for studying the potential function of miR-138-5p in TC progression.

LncRNA MIR217HG aggravates pressure-overload induced cardiac remodeling by activating miR-138/THBS1 pathway.

AIM: Cardiac hypertrophy and fibrosis are associated with cardiac remodeling and heart failure. We have previously shown that miRNA-217, embedded within the third intron of MIR217HG, aggravates pressure overload-induced cardiac hypertrophy by targeting phosphatase and tensin homolog. However, whether the MIR217HG transcript itself plays a role in cardiac remodeling remains unknown. METHODS: Real-time PCR assays and RNA in situ hybridization were performed to detect MIR217HG expression. Lentiviruses and adeno-associated viruses with a cardiac-specific promoter (cTnT) were used to control MIR217HG expression in vitro and in vivo. Transverse aortic constriction (TAC) surgery was performed to develop cardiac remodeling models. Cardiac structure and function were analyzed using echocardiography and invasive pressure-volume analysis. KEY FINDINGS: MIR217HG expression was increased in patients with heart failure. MIR217HG overexpression aggravated pressure-overload-induced myocyte hypertrophy and fibrosis both in vivo and in vitro, whereas MIR217HG knockdown reversed these phenotypes. Mechanistically, MIR217HG increased THBS1 expression by sponging miR-138. MiR-138 recognized the 3'UTR of THBS1 and repressed THBS1 expression in the absence of MIR217HG. Silencing THBS1 expression reversed MIR217HG-induced cardiac hypertrophy and remodeling. CONCLUSION: MIR217HG acts as a potent inducer of cardiac remodeling that may contribute to heart failure by activating the miR-138/THBS1 pathway.

[Retracted] Effects of miR­138­5p and miR­204­5p on the migration and proliferation of gastric cancer cells by targeting EGFR.

Following the publication of the above paper, it was drawn to the Editor's attention by a concerned reader that the numerous immunohistochemical images shown in Fig. 1D on p. 2626 exhibited a number of overlaps comparing among the data panels, such that data which were intended to show the results from differently performed experiments were likely to have been derived from a smaller number of original sources. A subsequent independent investigation of the data in this paper in the Editorial Office also revealed that certain of the cell migration and invasion assay data shown in Fig. 4A on p. 2629 were strikingly similar to data that had previously appeared in a couple of already published papers written by different authors at different research institutes.  Owing to the fact that the contentious data in Fig. 4 in the above article had already been published prior to its submission to Oncology Reports, in addition to the matter of several panels in Fig. 1D showing overlapping data, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 39: 2624-2634, 2018; DOI: 10.3892/or.2018.6389].

Icariin promotes osteogenic differentiation through the mmu_circ_0000349/mmu-miR-138-5p/Jumonji domain-containing protein-3 axis.

Circular RNAs (circRNAs) regulate Jumonji domain-containing protein-3 (JMJD3) by sponging with microRNAs (miRNAs). This study aimed to investigate the role of icariin on specific circRNA/miRNA/JMJD3 axis in osteogenic differentiation of MC3T3-E1 cells. CircRNA sequencing was performed on the MC3T3-E1 cells induced by osteogenic differentiation medium for 1 d (negative control (NC) group) and 14 d (osteogenesis group). And mmu_circ_0000349 was verified using Sanger sequencing, ribonuclease R degradation, and actinomycin D assay. The function of mmu_circ_0000349 was validated by detecting the expressions of osteogenic differentiation markers, alkaline phosphatase (ALP), and runt-related transcription (RUNX2), via real-time quantitative PCR (qPCR) and Western blotting or ALP and alizarin red staining assay. Dual luciferase reporter gene assay confirmed the relationship between mmu_circ_0000349 and mmu-miR-138-5p (or mmu-miR-138-5p and JMJD3). Meanwhile, the JMJD3 binding to mmu_circ_0000349 was screened using an RNA pull-down assay. qPCR and Western blotting confirmed the effect of icariin on the mmu_circ_0000349/mmu-miR-138-5p/JMJD3 axis and osteogenic differentiation. As MC3T3-E1 osteogenic differentiation progressed, the JMJD3 expression level increased. A total of 361 circRNAs exhibited differences between the NC and osteogenesis groups. After validation, mmu_circ_0000349 was further analyzed as it exhibited the largest expression. And mmu_circ_0000349 was identified as a stable circular structure. Overexpression of mmu_circ_0000349 increased the expression levels of ALP and RUNX2, enhanced ALP activity, and increased the number of mineralized nodules; contrarily, inhibition of mmu_circ_0000349 exerted opposite effects. The data also confirmed that mmu_circ_0000349 regulated JMJD3 by sponging with mmu-miR-138-5p. With the increase in icariin concentration and time for treatment, the expression levels of mmu_circ_0000349, JMJD3, ALP, and RUNX2 also increased, whereas that of mmu-miR-138-5p decreased. In conclusion, Icariin promoted osteogenic differentiation by regulating the mmu_circ_0000349/mmu-miR-138-5p/JMJD3 pathway. Therefore, this provides a theoretical basis for the treatment of diseases related to osteogenic differentiation.

Overexpression of MicroRNA-138 Affects the Proliferation and Invasion of Urothelial Carcinoma Cells by Suppressing SOX9 Expression.

SRY-box transcription factor 9 (SOX9) is important for sexual differentiation, chondrogenic differentiation, and cell proliferation in cancer. It acts as a target molecule of microRNA (miR)-138 in various tumors and is associated with tumor development and growth. In this study, we analyzed the functions of miR-138 and SOX9 in urothelial carcinoma. SOX9 was highly expressed in invasive urothelial carcinoma tissues. miR-138 precursor transfection of T24 and UMUC2 cells significantly decreased SOX9 expression, indicating that SOX9 is a miR-138 target in urothelial carcinoma. Moreover, miR-138 precursor or SOX9 small interfering RNA (siRNA) transfection decreased the proliferation of urothelial carcinoma cell lines. To further confirm that miR-138-SOX9 signaling is involved in cell proliferation and invasion, urothelial carcinoma cells were transfected with the miR-138 precursor or SOX9 siRNA. This transfection reduced the proliferation and invasion of cells via the promotion of autophagy and apoptosis and G0/G1 cell cycle arrest. These results suggest that miR-138-SOX9 signaling modulates the growth and invasive potential of urothelial carcinoma cells.

MiR-138-5p Upregulation during Neuronal Maturation Parallels with an Increase in Neuronal Survival.

Neuronal maturation is a process that plays a key role in the development and regeneration of the central nervous system. Although embryonic brain development and neurodegeneration have received considerable attention, the events that govern postnatal neuronal maturation are less understood. Among the mechanisms influencing such neuronal maturation processes, apoptosis plays a key role. Several regulators have been described to modulate apoptosis, including post-transcriptional regulation by microRNAs. This study aimed to analyze endogenous expression changes of miR-138-5p, as well as its main validated pro-apoptotic target caspase3, during the maturation of neuronal cultures and their response under apoptotic challenge. Our results point out that the observed opposite expression of miR-138-5p and its target caspase3 might modulate apoptosis favoring neuronal survival at distinct maturation stages. The unchanged expression of miR-138-5p in mature neurons contrasts with the significant downregulation in immature neurons upon apoptotic stimulation. Similarly, immunoblot and individual cellular assays confirmed that during maturation, not only the expression but processing of CASP-3 and caspase activity is reduced after apoptotic stimulation which results in a reduction of neuronal death. Further studies would be needed to determine a more detailed role of miR-138-5p in apoptosis during neuronal maturation and the synergistic action of several microRNAs acting cooperatively on caspase3 or other apoptotic targets.

The extract from Portulaca oleracea L. rehabilitates skin photoaging via adjusting miR-138-5p/Sirt1-mediated inflammation and oxidative stress.

Photoaging is the main form of external skin aging, and ultraviolet radiation is the main cause. Long-term ultraviolet radiation can cause oxidative stress, inflammation, immune responses, and skin cell apoptosis. Therefore, it is necessary to explore active products from plants to treat skin photoaging. C57BL/6J mice were randomly divided into control, model, and purslane (Portulaca oleracea L.) extract-treated groups (150, 300, and 600 mg/kg). Ultraviolet (UV) radiation induces skin photoaging. Histopathological changes in the skin were observed by hematoxylin and eosin (H&E), Masson's trichrome, and toluidine staining. Levels of hydroxyproline (HYP), hyaluronic acid (HA), collagen I (COL1), catalase (CAT), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) were measured. UVB-induced BJ and HaCaT cells were used to evaluate the effects of the crude extract. The effects of the purslane extract on miR-138-5p/Sirt1 signaling were then tested. The results showed that the purslane extract significantly increased cell viability in UVB-induced cells and decreased oxidative damage and inflammation. In addition, the extract affected the miR-138-5p levels in vivo and in vitro, and increased the levels of the target gene Sirt1. In UVB-induced cells, purslane extract significantly altered the expression levels of genes or proteins associated with miR-138-5p/Sirt1 signaling. Inflammation and oxidative damage were significantly enhanced when miR-138-5p was overexpressed, and the expression levels of the genes and proteins were reversed by the extract. Co-transfection with the miR-138-5p inhibitor and si-Sirt1 showed the same effects as the extract on the signal. Similar results have been observed in mice. In summary, purslane extract showed potent protective effects against skin photoaging by regulating the miR-138-5p/Sirt1 axis and should be used as a natural product for skin care.

MicroRNA-138: an emerging regulator of skeletal development, homeostasis, and disease.

Noncoding microRNAs are powerful epigenetic regulators of cellular processes by their ability to target and suppress expression of numerous protein-coding mRNAs. This multitargeting function is a unique and complex feature of microRNAs. It is now well-described that microRNAs play important roles in regulating the development and homeostasis of many cell/tissue types, including those that make up the skeletal system. In this review, we focus on microRNA-138 (miR-138) and its effects on regulating bone and cartilage cell differentiation and function. In addition to its reported role as a tumor suppressor, miR-138 appears to function as an inhibitor of osteoblast differentiation. This review provides additional information on studies that have attempted to alter miR-138 expression in vivo as a means to dampen ectopic calcification or alter bone mass. However, a review of the published literature on miR-138 in cartilage reveals a number of contradictory and inconclusive findings with respect to regulating chondrogenesis and chondrocyte catabolism. This highlights the need for more research in understanding the role of miR-138 in cartilage biology and disease. Interestingly, a number of studies in other systems have reported miR-138-mediated effects in dampening inflammation and pain responses. Future studies will reveal if a multifunctional role of miR-138 involving suppression of ectopic bone, inflammation, and pain will be beneficial in skeletal conditions such as osteoarthritis and heterotopic ossification.

MiR-138-5p improves the chemosensitivity of MDA-MB-231 breast cancer cell line to paclitaxel.

BACKGROUND: Chemotherapy is a predominant strategy for breast cancer (BC) treatment and paclitaxel (PTX) has been known as a conventional chemotherapeutic drug. However, insensitivity of BC cells to PTX limits the anti-tumor effects of this agent. MicroRNAs are closely related to BC which are suggested as therapeutic factors in the combination therapy of BC. We examined the possible efficacy of miR-138-5p restoration in combination with PTX to impove BC treatment. METHODS: The human breast cancer cell line MDA-MB-231 was transfected with miR-138-5p mimics and treated with PTX, in a combined or separate manner. The MTT assay was accomplished to determine inhibitory doses of PTX. Annexin V/PI assay and DAPI staining were applied to evaluate apoptosis. Flow cytometry was applied to determine cells arrested in different phases of the cell-cycle. Expression levels of molecular factors involved in cell migration, proliferation, apoptosis, and cell cycle were determined via western blotting and qRT-PCR. RESULTS: MiR-138-5p combined with PTX suppressed cell migration via modulating MMP2, E-cadherin, and vimentin and sustained colony formation and proliferation by downregulation of the PI3K/AKT pathway. qRT-PCR showed that miR-138-5p increases BC chemosensitivity to PTX by regulating the apoptosis factors, including Bcl-2, Bax, Caspase 3, and Caspase 9. Moreover, miR-138-5p restoration and paclitaxel therapy combined arrest the cells in the sub-G1 and G1 phases of cell cycle by regulating p21, CCND1, and CDK4. CONCLUSIONS: Restored miR-138-5p intensified the chemosensitivity of MDA-MB-231 cell line to PTX, and the combination of miR-138-5p with PTX might represent a novel approach in BC treatment.

Brucea javanica oil inhibits tongue squamous cell invasion and metastasis by regulating miR-138-EZH2 pathway.

Tongue squamous cell carcinoma (TSCC) is one of the most common malignant tumors of head and neck. Its incidence is on the rise, and the proportion of young patients is gradually increasing, which is prone to tumor recurrence and metastasis. At present, there is no effective method to completely treat TSCC. Studies have shown that brucea javanica oil (BJO) has good antitumor activity against lung cancer and gastrointestinal tumors, but its therapeutic effect on TSCC is not clear. We have previously confirmed that oleic acid, the main component of BJO, can induce apoptosis of TSCC and reduce its invasion and metastasis ability. However, the anticancer effect and mechanism of BJO in TSCC remain unclear. In order to further explore the effects of BJO on the biological characteristics of TSCC cells, we studied the effects of different concentrations of BJO on the migration, invasion ability and epithelial mesenchymal transition (EMT) progression of TSCC cells and the possible mechanisms through in vitro experiments. We found that BJO could inhibit the invasion and metastasis of TSCC and up-regulate miR-138. After BJO treatment, the expression of E-cad was significantly increased, while the expression of EZH2, Slug, p-ERK1/2 and Vimentin was significantly decreased. EZH2 is a miR-138 target gene involved in TSCC. BJO inhibits TSCC invasion and metastasis by regulating the miR-138-EZH2 pathway. In vivo experiments have also well demonstrated the targeting effect of this pathway. This study provides a new therapeutic strategy for the treatment of TSCC.