MicroRNA-2285f regulates milk fat metabolism by targeting MAP2K2 in bovine mammary epithelial cells.

In this study, Holstein dairy cows raised in Ningxia were selected as the research object. Mammary epithelial cells (BMECs) were extracted from the milk of eight Holstein cows with significantly different milk fat expression rates and transcribed for sequencing. Bioinformatics analysis was used to analyse the correlation of fat milk percentage, and the critical miR-2285f regulating milk fat was screened out. The target gene binding sites were predicted, and 293T cells and mammary epithelial cells were used as miRNA and target gene models for functional verification in vitro. The tissue difference of miR-2285f Holstein cows was quantitatively analysed by transfecting miR-2285f mimic and inhibitor. Assay (dual luciferase reporter gene assay) and quantitative real-time PCR (quantitative real-time PCR, qRT-PCR), triglyceride (TAG) detection, oil red O detection of lipid droplets, Western Blot assay, Edu and Flow cytometry, The molecular regulatory effects of miR-2285f and target gene MAP2K2 on milk fat metabolism of Holstein dairy cows were studied. The wild-type vector and mutant vector of map2k2-3'utr were constructed, and double luciferase reporting experiments were conducted to verify that MAP2K2 was one of the target genes of miR-2285f. According to qRT-PCR and Western Blot analysis, miR-2285f mainly regulates the expression of MAP2K2 protein in BMECs at the translation level. Bta-miR-2285f can promote cell proliferation and slow cell apoptosis by regulating MAP2K2. Bta-miR-2285f can promote triglyceride (TAG) and lipid droplet accumulation in mammary epithelial cells by targeting MAP2K2. Bta-miR-2285f can regulate protein levels of fat milk marker gene PPARG by targeting MAP2K2. In conclusion, miR-2285f can target the expression of the MAP2K2 gene, promote the proliferation of dairy mammary epithelial cells, inhibit cell apoptosis and regulate the milk fat metabolism in dairy mammary epithelial cells. The results of this study revealed the function of miR-2285f in regulating the differential expression of fat milk in Holstein dairy cows at the cellular level. They provided a theoretical and experimental basis for analysing the regulation network of milk fat synthesis of Holstein dairy cows and the molecular breeding of dairy cows.

HuR facilitates miR-93-5p-induced activation of MAP3K2 translation via MAP3K2 3'UTR ARE2 in hepatocellular carcinoma.

MicroRNAs (miRNAs) can positively regulate gene expression through an unconventional RNA activation mechanism involving direct targeting 3' untranslated regions (UTRs). Our prior study found miR-93-5p activates mitogen-activated protein kinase kinase kinase 2 (MAP3K2) in hepatocellular carcinoma (HCC) via its 3'UTR. However, the underlying mechanism remains elusive. Here, we identified two candidate AU-rich element (ARE) motifs (ARE1 and ARE2) adjacent to the miR-93-5p binding site located within the MAP3K2 3'UTR using AREsite2. Luciferase reporter and translation assays validated that only ARE2 participated in MAP3K2 activation. Integrative analysis revealed that human antigen R (HuR), an ARE2-associated RNA-binding protein (RBP), physically and functionally interacted with the MAP3K2 3'UTR. Consequently, an HuR-ARE2 complex was shown to facilitate miR-93-5p-mediated upregulation of MAP3K2 expression. Furthermore, bioinformatics analysis and studies of HCC cells and specimens highlighted an oncogenic role for HuR and positive HuR-MAP3K2 expression correlation. HuR is also an enhancing factor in the positive feedback circuit comprising miR-93-5p, MAP3K2, and c-Jun demonstrated in our prior study. The newly identified HuR-ARE2 involvement enriches the mechanism of miR-93-5p-driven MAP3K2 activation and suggests new therapeutic strategies warranted for exploration in HCC.

The SMYD3-MAP3K2 signaling axis promotes tumor aggressiveness and metastasis in prostate cancer.

Aberrant activation of Ras/Raf/mitogen-activated protein kinase (MAPK) signaling is frequently linked to metastatic prostate cancer (PCa); therefore, the characterization of modulators of this pathway is critical for defining therapeutic vulnerabilities for metastatic PCa. The lysine methyltransferase SET and MYND domain 3 (SMYD3) methylates MAPK kinase kinase 2 (MAP3K2) in some cancers, causing enhanced activation of MAPK signaling. In PCa, SMYD3 is frequently overexpressed and associated with disease severity; however, its molecular function in promoting tumorigenesis has not been defined. We demonstrate that SMYD3 critically regulates tumor-associated phenotypes via its methyltransferase activity in PCa cells and mouse xenograft models. SMYD3-dependent methylation of MAP3K2 promotes epithelial-mesenchymal transition associated behaviors by altering the abundance of the intermediate filament vimentin. Furthermore, activation of the SMYD3-MAP3K2 signaling axis supports a positive feedback loop continually promoting high levels of SMYD3. Our data provide insight into signaling pathways involved in metastatic PCa and enhance understanding of mechanistic functions for SMYD3 to reveal potential therapeutic opportunities for PCa.

E3 ubiquitin ligase NEDD4L negatively regulates inflammation by promoting ubiquitination of MEKK2.

Aberrant activation of inflammation signaling triggered by tumor necrosis factor α (TNF-α), interleukin-1 (IL-1), and interleukin-17 (IL-17) is associated with immunopathology. Here, we identify neural precursor cells expressed developmentally down-regulated gene 4-like (NEDD4L), a HECT type E3 ligase, as a common negative regulator of signaling induced by TNF-α, IL-1, and IL-17. NEDD4L modulates the degradation of mitogen-activated protein kinase kinase kinase 2 (MEKK2) via constitutively and directly binding to MEKK2 and promotes its poly-ubiquitination. In interleukin-17 receptor (IL-17R) signaling, Nedd4l knockdown or deficiency enhances IL-17-induced p38 and NF-κB activation and the production of proinflammatory cytokines and chemokines in a MEKK2-dependent manner. We further show that IL-17-induced MEKK2 Ser520 phosphorylation is required not only for downstream p38 and NF-κB activation but also for NEDD4L-mediated MEKK2 degradation and the subsequent shutdown of IL-17R signaling. Importantly, Nedd4l-deficient mice show increased susceptibility to IL-17-induced inflammation and aggravated symptoms of experimental autoimmune encephalomyelitis (EAE) in IL-17R signaling-dependent manner. These data suggest that NEDD4L acts as an inhibitor of IL-17R signaling, which ameliorates the pathogenesis of IL-17-mediated autoimmune diseases.

miRNA-338-3p inhibits the migration, invasion and proliferation of human lung adenocarcinoma cells by targeting MAP3K2.

OBJECTIVE: This study aimed to investigate the effects of micro ribonucleic acid (miR)-338-3p on the migration, invasion and proliferation of lung adenocarcinoma (LUAD) cells. METHODS: Bioinformatics analysis was employed to evaluate the function and expression of related genes in lung cancer. Human A549 and NCI-H1299 cells cultured to logarithmic growth stage were assigned to negative control (NC) mimic group, miR-338-3p mimic group (miR-mimic group), NC inhibitor group and miR-338-3p inhibitor group (miR-inhibitor group) treated with or without MAP3K2 overexpression (OE)-lentivirus, or TBHQ or FR180204. Transwell assay, cell colony formation assay, Western blotting and cell-cycle analysis were carried out. RESULTS: Bioinformatics results manifested that miR-338 and MAP3K2 were involved in LUAD. The expression levels of MAP3K2, p-ERK1/2, MMP-2, MMP-3, MMP-9, cyclin A2 and cyclin D1 were increased after addition of miR-338-3p inhibitor, consistent with the raised amount of LUAD cells in migration and invasion experiments and number of colonies formed, as well as the cell cycle, but miR-338-3p mimic reversed these results. Moreover, MAP3K2 overexpression elevated the level of p-ERK1/2. Meanwhile, after treatment with TBHQ or FR180204, the influence of miR-338-3p inhibitor or mimic was also verified. CONCLUSIONS: MiR-338-3p overexpression can modulate the ERK1/2 signaling pathway by targeting MAP3K2, thus inhibiting the migration, invasion and proliferation of human LUAD cells.

MiR-20a-5p facilitates cartilage repair in osteoarthritis via suppressing mitogen-activated protein kinase kinase kinase 2.

Bone marrow mesenchymal stem cell (BMSC) chondrogenic differentiation contributes to the treatment of osteoarthritis (OA). Numerous studies have indicated that microRNAs (miRNAs) regulate the pathogenesis and development of multiple disorders, including OA. Nevertheless, the role of miR-20a-5p in OA remains obscure. Forty male C57BL/6 mice were divided into four groups and were surgically induced OA or underwent sham surgery in the presence or absence of miR-20a-5p. Flow cytometry was implemented to detect surface markers of BMSCs. Reverse transcription quantitative polymerase chain reaction revealed the upregulation of miR-20a-5p during BMSC chondrogenic differentiation. Western blotting displayed that miR-20a-5p inhibition decreased protein levels of cartilage matrix markers but enhanced those of catabolic and hypertrophic chondrocyte markers in BMSCs. Alcian blue staining, hematoxylin­eosin staining and micro-CT revealed that miR-20a-5p inhibition restrained chondrogenic differentiation and miR-20a-5p overexpression promoted the repair of damaged cartilage and subchondral bone, respectively. Luciferase reporter assay identified that mitogen activated protein kinase kinase kinase 2 (Map3k2) was a target of miR-20a-5p in BMSCs. Moreover, the expression of miR-20a-5p and Map3k2 was negatively correlated in murine cartilage tissues. Knocking down Map3k2 could rescue the suppressive influence of miR-20a-5p inhibition on chondrogenic differentiation of BMSCs. In conclusion, miR-20a-5p facilitates BMSC chondrogenic differentiation and contributes to cartilage repair in OA by suppressing Map3k2.

CircRNA circBACH1 facilitates hepatitis B virus replication and hepatoma development by regulating the miR-200a-3p/MAP3K2 axis.

BACKGROUND: Hepatitis B virus (HBV) is a top contributor to hepatoma. Circular RNAs (circRNAs) have been elucidated to have a close connection with HBV-induced hepatoma. This study aimed to explore the role of circRNA BTB domain and CNC homolog 1 (circBACH1) in HBV replication and hepatoma progression, as well as the potential mechanistic pathway. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed to assess the expression of circBACH1, microRNA (miR)-200a-3p, and mitogen-activated protein kinase kinase kinase 2 (MAP3K2). HBV replication was determined by enzyme-linked immunosorbent assay (ELISA) and qRT-PCR assay. Cell viability and clonogenicity were detected via Cell Counting Kit-8 (CCK-8) assay and colony formation assay, respectively. Cell metastasis was examined by Transwell assay and wound healing assay. Annexing-V/PI staining was employed to monitor cell apoptosis using flow cytometry. Levels of MAP3K2, proliferation- and apoptosis-related proteins were analyzed by Western blotting. Target interaction between miR-200a-3p and circBACH1 or MAP3K2 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The role of circBACH1 in vivo was investigated by xenograft model assay. RESULTS: Expression of circBACH1 and MAP3K2 was increased, while miR-200a-3p expression was decreased in HCC tissues and HBV-transfected hepatoma cells. Depletion of circBACH1 or miR-200a-3p overexpression impeded HBV replication, proliferation, and metastasis in HBV-transfected hepatoma cells. CircBACH1 was able to regulate MAP3K2 expression by sponging miR-200a-3p. CircBACH1 regulated HBV replication and hepatoma progression through the miR-200a-3p/MAP3K2 pathway. Moreover, circBACH1 deficiency hampered tumor growth in vivo. CONCLUSION: CircBACH1 knockdown had inhibitory effects on HBV replication and hepatoma progression, at least partly by modulating the miR-200a-3p/MAP3K2 axis.

MicroRNA-181a restricts human γδ T cell differentiation by targeting Map3k2 and Notch2.

γδ T cells are a conserved population of lymphocytes that contributes to anti-tumor responses through its overt type 1 inflammatory and cytotoxic properties. We have previously shown that human γδ T cells acquire this profile upon stimulation with IL-2 or IL-15, in a differentiation process dependent on MAPK/ERK signaling. Here, we identify microRNA-181a as a key modulator of human γδ T cell differentiation. We observe that miR-181a is highly expressed in patients with prostate cancer and that this pattern associates with lower expression of NKG2D, a critical mediator of cancer surveillance. Interestingly, miR-181a expression negatively correlates with an activated type 1 effector profile obtained from in vitro differentiated γδ T cells and miR-181a overexpression restricts their levels of NKG2D and TNF-α. Upon in silico analysis, we identify two miR-181a candidate targets, Map3k2 and Notch2, which we validate via overexpression coupled with luciferase assays. These results reveal a novel role for miR-181a as critical regulator of human γδ T cell differentiation and highlight its potential for manipulation of γδ T cells in next-generation immunotherapies.

LncRNA-ATB regulates epithelial-mesenchymal transition progression in pulmonary fibrosis via sponging miR-29b-2-5p and miR-34c-3p.

Dysregulation of non-coding RNAs (ncRNAs) has been proved to play pivotal roles in epithelial-mesenchymal transition (EMT) and fibrosis. We have previously demonstrated the crucial function of long non-coding RNA (lncRNA) ATB in silica-induced pulmonary fibrosis-related EMT progression. However, the underlying molecular mechanism has not been fully elucidated. Here, we verified miR-29b-2-5p and miR-34c-3p as two vital downstream targets of lncRNA-ATB. As opposed to lncRNA-ATB, a significant reduction of both miR-29b-2-5p and miR-34c-3p was observed in lung epithelial cells treated with TGF-ß1 and a murine silicosis model. Overexpression miR-29b-2-5p or miR-34c-3p inhibited EMT process and abrogated the pro-fibrotic effects of lncRNA-ATB in vitro. Further, the ectopic expression of miR-29b-2-5p and miR-34c-3p with chemotherapy attenuated silica-induced pulmonary fibrosis in vivo. Mechanistically, TGF-ß1-induced lncRNA-ATB accelerated EMT as a sponge of miR-29b-2-5p and miR-34c-3p and shared miRNA response elements with MEKK2 and NOTCH2, thus relieving these two molecules from miRNA-mediated translational repression. Interestingly, the co-transfection of miR-29b-2-5p and miR-34c-3p showed a synergistic suppression effect on EMT in vitro. Furthermore, the co-expression of these two miRNAs by using adeno-associated virus (AAV) better alleviated silica-induced fibrogenesis than single miRNA. Approaches aiming at lncRNA-ATB and its downstream effectors may represent new effective therapeutic strategies in pulmonary fibrosis.

MEKK2 and MEKK3 orchestrate multiple signals to regulate Hippo pathway.

The Hippo pathway is an evolutionarily conserved signaling pathway that controls organ size in animals via the regulation of cell proliferation and apoptosis. It consists of a kinase cascade, in which MST1/2 and MAP4Ks phosphorylate and activate LATS1/2, which in turn phosphorylate and inhibit YAP/TAZ activity. A variety of signals can modulate LATS1/2 kinase activity to regulate Hippo pathway. However, the full mechanistic details of kinase-mediated regulation of Hippo pathway signaling remain elusive. Here, we report that TNF activates LATS1/2 and inhibits YAP/TAZ activity through MEKK2/3. Furthermore, MEKK2/3 act in parallel to MST1/2 and MAP4Ks to regulate LATS1/2 and YAP/TAZ in response to various signals, such as serum and actin dynamics. Mechanistically, we show that MEKK2/3 interact with LATS1/2 and YAP/TAZ and phosphorylate them. In addition, Striatin-interacting phosphatase and kinase (STRIPAK) complex associates with MEKK3 via CCM2 and CCM3 to inactivate MEKK3 kinase activity. Upstream signals of Hippo pathway trigger the dissociation of MEKK3 from STRIPAK complex to release MEKK3 activity. Our work has uncovered a previous unrecognized regulation of Hippo pathway via MEKK2/3 and provides new insights into molecular mechanisms for the interplay between Hippo-YAP and NF-κB signaling and the pathogenesis of cerebral cavernous malformations.

CircPUM1 promotes hepatocellular carcinoma progression through the miR-1208/MAP3K2 axis.

Hepatocellular carcinoma (HCC) is a common disease with a significant mortality, and there is no effective treatment for advanced patients. Growing evidence indicates that circRNAs are closely related to HCC progression, may be used as biomarkers and targets for the diagnosis and treatment of HCC. Recent researches have shown that circPUM1 may play an oncogene role in a variety of human cancers, but its role in HCC development has not been reported. Our study found that circPUM1 could promote the proliferation, migration and invasion of HCC cells in vitro. In addition, in vivo studies showed that circPUM1 could increase the development of HCC tumours and regulate the expression of EMT-related proteins. Furthermore, we demonstrated that circPUM1 could promote the development of HCC by up-regulating the expression of MAP3K2 via sponging miR-1208. Our study suggested that circPUM1 may be a potential therapeutic target for HCC.

MEKK2 mediates aberrant ERK activation in neurofibromatosis type I.

Neurofibromatosis type I (NF1) is characterized by prominent skeletal manifestations caused by NF1 loss. While inhibitors of the ERK activating kinases MEK1/2 are promising as a means to treat NF1, the broad blockade of the ERK pathway produced by this strategy is potentially associated with therapy limiting toxicities. Here, we have sought targets offering a more narrow inhibition of ERK activation downstream of NF1 loss in the skeleton, finding that MEKK2 is a novel component of a noncanonical ERK pathway in osteoblasts that mediates aberrant ERK activation after NF1 loss. Accordingly, despite mice with conditional deletion of Nf1 in mature osteoblasts (Nf1fl/fl;Dmp1-Cre) and Mekk2-/- each displaying skeletal defects, Nf1fl/fl;Mekk2-/-;Dmp1-Cre mice show an amelioration of NF1-associated phenotypes. We also provide proof-of-principle that FDA-approved inhibitors with activity against MEKK2 can ameliorate NF1 skeletal pathology. Thus, MEKK2 functions as a MAP3K in the ERK pathway in osteoblasts, offering a potential new therapeutic strategy for the treatment of NF1.

MicroRNA-338 in MSCs-derived exosomes inhibits cardiomyocyte apoptosis in myocardial infarction.

OBJECTIVE: Myocardial infarction (MI) is caused by myocardial ischemia and hypoxia, which causes irreversible damage to the myocardium and seriously endangers human health. Exosomes are small, monolayer-structured extracellular vesicles that transport proteins, lipids, mRNAs, and miRNAs between cells. Mesenchymal stem cells (MSCs) can secrete a large number of exosomes and play a role in many pathophysiological processes. The purpose of this paper was to investigate the role of exosomal microRNA-338 (miR-338) in MI and its underlying mechanism of action. MATERIALS AND METHODS: We transfected rat bone marrow-derived MSCs with miR-338 mimic or negative control and extracted exosomes secreted by MSCs. Expression of miR-338 in MSCs, exosomes, and H9c2 cells co-cultured with exosomes was detected by PCR. Then, we treated H9c2 cells with H2O2. We transfected miR-338 inhibitor into H9c2 cells co-cultured with exosomes to further study the function of miR-338. Apoptosis of H9c2 cells were observed by Western blot, flow cytometry, and cell staining. We also established a MI rat model to study the function in vivo and injected exosomes in the myocardium. Seven days later, we used echocardiography to detect the heart function of rats. RESULTS: MiR-338 was upregulated in MSCs transfected with miR-338 mimic, exosomes, and H9c2 cells co-cultured with exosomes. When H9c2 cells were co-cultured with exosomes overexpressing miR-338, the expression of Bax was decreased while the expression of Bcl-2 was increased, and the apoptosis rate was also decreased as shown in flow cytometry, and the amount of caspase3 fluorescence was also decreased. Cardiac function was markedly improved after intramyocardial injection of exosomes overexpressing miR-338 in rats. It was demonstrated using computational tools, Western blot, and Luciferase reporter gene experiments that miR-338 could regulate JNK pathway via targeting MAP3K2. CONCLUSIONS: Exosomal miR-338 can inhibit cardiomyocyte apoptosis and improve cardiac function in rats with myocardial infarction by regulating MAP3K2/JNK signaling pathway.

microRNA-93-5p promotes hepatocellular carcinoma progression via a microRNA-93-5p/MAP3K2/c-Jun positive feedback circuit.

Cumulative evidence suggests that microRNAs (miRNAs) promote gene expression in cancers. However, the pathophysiologic relevance of miRNA-mediated RNA activation in hepatocellular carcinoma (HCC) remains to be established. Our previous miRNA expression profiling in seven-paired HCC specimens revealed miR-93-5p as an HCC-related miRNA. In this study, miR-93-5p expression was assessed in HCC tissues and cell lines by quantitative real-time PCR and fluorescence in situ hybridization. The correlation of miR-93-5p expression with survival and clinicopathological features of HCC was determined by statistical analysis. The function and potential mechanism of miR-93-5p in HCC were further investigated by a series of gain- or loss-of-function experiments in vitro and in vivo. We identified that miR-93-5p, overexpressed in HCC specimens and cell lines, leads to poor outcomes in HCC cases and promotes proliferation, migration, and invasion in HCC cell lines. Mechanistically, rather than decreasing target mRNA levels as expected, miR-93-5p binds to the 3'-untranslated region (UTR) of mitogen-activated protein kinase kinase kinase 2 (MAP3K2) to directly upregulate its expression and downstream p38 and c-Jun N-terminal kinase (JNK) pathway, thereby leading to cell cycle progression in HCC. Notably, we also demonstrated that c-Jun, a downstream effector of the JNK pathway, enhances miR-93-5p transcription by targeting its promoter region. Besides, downregulation of miR-93-5p significantly retarded tumor growth, while overexpression of miR-93-5p accelerated tumor growth in the HCC xenograft mouse model. Altogether, we revealed a miR-93-5p/MAP3K2/c-Jun positive feedback loop to promote HCC progression in vivo and in vitro, representing an RNA-activating role of miR-93-5p in HCC development.

MicroRNA-335 inhibits the growth, chemo-sensitivity, and metastasis of human breast cancer cells by targeting MAP3K2.

PURPOSE: Molecular mechanism of breast cancer (BC) is relatively unknown and its metastasis is highly complicated. In this context, the characterization of miR-335 was undertaken in (BC). METHODS: qRT-PCR was carried out to analyze the expression of miR-335 in three different (BC) cell lines and normal epithelial breast cell line. Cell proliferation, survival, and viability of (BC) cells were estimated by MTT assay, clonogenic colony forming, and DAPI staining methods, respectively. Target identification of miR-335 was made through online bioinformatics and validated through the correlation of gene expression, western blotting experiments, and luciferase reporter assay. Cell migration and invasion were analyzed through transwell chamber assay. RESULTS: miR-335 is downregulated in (BC) cells and has inhibitory effect on cell growth, which was manifested as decline in cell survival and loss of cancer cell viability . Further, the chemo-sensitivity of (BC) cells to paclitaxel and doxorubicin was seen to be enhanced under miR-335 overexpression. miR-335 also inhibited the migration and invasion of cancer cells. MAP3K2 was shown to be the target gene of miR-335 and the silencing of MAP3K2 was seen to mimic the growth inhibitory effect of miR-335. The overexpression of MAP3K2 reversed the growth inhibition in miR-335 mimics-transfected BC cells. CONCLUSION: miR-335 has growth inhibitory effect against BC and negatively regulates the cell migration and invasion along with enhancement of chemo-sensitivity of cancer cells.

MIR205HG acts as a ceRNA to expedite cell proliferation and progression in lung squamous cell carcinoma via targeting miR-299-3p/MAP3K2 axis.

INTRODUCTION: Long noncoding RNAs (lncRNAs) have been associated with many types of cancers, but their molecular mechanisms in lung squamous cell carcinoma (LUSC) have not been fully studied. Therefore, the current study investigated the regulation role of microRNA-205 host gene (MIR205HG) in LUSC and recognized the target genes managed by this lncRNA. METHODS: MIR205HG expression was assessed by the quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The effects of silenced MIR205HG on cell biological behaviors were detected by colony formation assay, transwell assay, flow cytometry analysis and western blot analysis. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized to proof the binding relationship between miR-299-3p and MIR205HG/mitogen-activated protein kinase kinase kinase 2 (MAP 3 K2). RESULTS: The expression levels of MIR205HG in LUSC tissues and cell lines were obviously up-regulated. Down-regulation of MIR205HG expression remarkably reduced cell proliferation, migration and epithelial-to-mesenchymal transition (EMT) progression, whereas promoted cell apoptosis. MIR205HG could bind with miR-299-3p and down-regulation of MIR205HG elevated miR-299-3p expression. MAP 3 K2 acted as the target gene of miR-299-3p and was up-regulated by MIR205HG overexpression. Overexpressing MAP 3 K2 could counteract the effects of down-regulating MIR205HG on LUSC progression to some degree. CONCLUSION: MIR205HG acts as a competing endogenous RNA (ceRNA) to expedite cell proliferation and progression via targeting miR-299-3p in LUSC.

Long noncoding RNA MYLK-AS1 promotes growth and invasion of hepatocellular carcinoma through the EGFR/HER2-ERK1/2 signaling pathway.

The epidermal growth factor receptor (EGFR) family members EGFR and HER2 play pivotal roles in oncogenesis and tumor progression. Anticancer drugs targeting EGFR and HER2 have been developed. Long noncoding RNAs (lncRNAs) have been reported to regulate cancer development and progression through signaling pathways. However, lncRNAs that regulate EGFR and HER2 expression remain unknown. Here, we show that lncRNA myosin light chain kinase-antisense RNA 1 (MYLK-AS1) promotes EGFR and HER2 expression and activates their downstream signaling pathway. MYLK-AS1 increases hepatocellular carcinoma (HCC) cell proliferation, migration, and invasion in vitro. Consistently, MYLK-AS1 knockdown hinders tumor growth in vivo. Mechanistically, MYLK-AS1 enhances HCC cell proliferation, migration, and invasion through stimulating the EGFR/HER2-extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. In addition, MYLK-AS1 is overexpressed in HCC patients and negatively correlated with HCC prognosis. Thus, MYLK-AS1 is an upstream regulator of EGFR/HER2, and acts as an oncogene, suggesting an additional target for cancer therapeutics.

IL-17 alters the mesenchymal stem cell niche towards osteogenesis in cooperation with osteocytes.

Bone remodeling is a strictly regulated dynamic process that cycles between bone formation and resorption, and interleukin-17 (IL-17) critically orchestrates the activation and differentiation of both osteoblasts and osteoclasts. Mesenchymal stem cells (MSCs) within their native environment receive biochemical stimuli from surrounding cells that influences their differentiation into bone precursors, while the roles of osteocytes in regulating the osteogenic differentiation of MSCs remain unclear. This study investigated the specific roles of IL-17 signaling cascades and osteocyte-specific pathways in the osteogenesis of MSCs. Using a transwell coculture (CC) system, we explored the effects of osteocytes and osteoblasts on the osteogenesis of MSCs with and without IL-17 supplementation. A polycaprolactone (PCL) three-dimensional (3D) culture model was used to evaluate their osteogenic potential in the presence of osteocytes and IL-17. Notably, IL-17 induced osteogenesis in MSCs, which could be attenuated by blocking IL-17 receptor A. The osteogenic differentiation of MSCs promoted by IL-17 was further enhanced by CC with osteocytes. Moreover, proinflammatory cytokines IL-6 and IL-1ß played an important role in IL-17-dependent differentiation, via the phosphorylation of AKT, signal transducer and activator of transcription 3, and extracellular signal-regulated kinase 1/2 signaling pathways in the MSC niche. The present study confirms a synergistic effect of osteocytes and IL-17 in the production of biochemical signals to stimulate the osteogenic differentiation of MSCs, which could be further promoted in the PCL 3D-scaffold. These findings provide important insight into the mechanisms of MSCs activation and osteogenic differentiation within the native stem cell niche, and suggest a possible role of IL-17 in bone tissue engineering.

Prevention of calpain-dependent degradation of STK38 by MEKK2-mediated phosphorylation.

Serine-threonine kinase 38 (STK38) is a member of the protein kinase A (PKA)/PKG/PKC-family implicated in the regulation of cell division and morphogenesis. However, the molecular mechanisms underlying STK38 stability remain largely unknown. Here, we show that treatment of cells with either heat or the calcium ionophore A23187 induced STK38 degradation. The calpain inhibitor calpeptin suppressed hyperthermia-induced degradation or the appearance of A23187-induced cleaved form of STK38. An in vitro cleavage assay was then used to demonstrate that calpain I directly cleaves STK38 at the proximal N-terminal region. Deletion of the N-terminal region of STK38 increased its stability against hyperthermia. We further demonstrated that the MAPKK kinase (MAP3K) MEKK2 prevented both heat- and calpain-induced cleavage of STK38. MEKK2 knockdown enhanced hyperthermia-induced degradation of STK38. We performed an in vitro MEKK2 assay and identified the key regulatory site in STK38 phosphorylated by MEKK2. Experiments with a phosphorylation-defective mutant demonstrated that phosphorylation of Ser 91 is important for STK38 stability, as the enzyme is susceptible to degradation by the calpain pathway unless this residue is phosphorylated. In summary, we demonstrated that STK38 is a calpain substrate and revealed a novel role of MEKK2 in the process of STK38 degradation by calpain.

LncRNA FOXD3-AS1 promotes proliferation, invasion and migration of cutaneous malignant melanoma via regulating miR-325/MAP3K2.

PURPOSE: The aim was to study the mechanism of LncRNA FOXD3-AS1 in cutaneous melanoma. METHODS: FOXD3-AS1 levels in 47 pairs of melanoma samples were detected. We used qRT-PCR to detect FOXD3-AS1, miR-325 and MAP3K2 expression in different staging samples and cutaneous melanoma cell lines. We used Kaplan-Meier curve to analyze survival rate in patients with FOXD3-AS1 high and low expression. Sh-FOXD3-AS1, miR-325, miR-325 inhibitor and oeMAP3K2 were transfected. The proliferation of A375 and SK-MEL-1 was detected by CCK8 and EdU labeling assay and cell clone formation assay. Dual luciferase reporter assay and pull down assay was used to confirm the binding site of FOXD3-AS1, miR-325 and MAP3K2. Flow cytometry was applied to detect the effect of lncRNA on cell cycle. The migration and invasion ability were detected by transwell assay. RESULTS: LncRNA FOXD3-AS1 highly expressed in cutaneous melanoma cells and tissues. Patients with highly expressed LncRNA FOXD3-AS1 were always with shorter overall survival time. When LncRNA FOXD3-AS1 was knockdown, proliferation, invasion and migration of cutaneous malignant melanoma, and tumor weight was inhibited, and cell cycle was arrested. LncRNA FOXD3-AS1 negatively regulated the expression of miR-325, and then improved the level of MAP3K2. MiR-325 was with similarly effects on above biological process, and MAP3K2 overexpression could rescue the influence of sh-FOXD3-AS1. Tumor volume and weight were measured to confirm the effect of sh-FOXD3-AS1 in vivo. CONCLUSION: LncRNA FOXD3-AS1 could promote proliferation, invasion and migration of cutaneous malignant melanoma via regulating miR-325/MAP3K2 axis.