Treadmill training improves lung function and inhibits alveolar cell apoptosis in spinal cord injured rats

Secondary lung injury after SCI is a major cause of patient mortality, with apoptosis playing a key role. This study aimed to explore the impact of treadmill training and miR145-5p on the MAPK/Erk signaling pathway and apoptosis in rats with complete SCI. SD rats were used to establish T10 segmental complete SCI models and underwent treadmill training 3, 7, or 14 days postinjury. Various techniques including arterial blood gas analysis, lung wet/dry weight ratio, HE staining, immunofluorescence staining, immunohistochemical staining, qRT-PCR, and Western blotting were employed to assess alterations in lung function and the expression levels of crucial apoptosis-related factors. In order to elucidate the specific mechanism, the impact of miR145-5p on the MAPK/Erk pathway and its role in apoptosis in lung cells were confirmed through miR145-5p overexpression and knockdown experiments. Following spinal cord injury (SCI), an increase in apoptosis, activation of the MAPK/Erk pathway, and impairment of lung function were observed in SCI rats. Conversely, treadmill training resulted in a reduction in alveolar cell apoptosis, suppression of the MAPK/Erk pathway, and enhancement of lung function. The gene MAP3K3 was identified as a target of miR145-5p. The influence of miR145-5p on the MAPK/Erk pathway and its impact on apoptosis in alveolar cells were confirmed through the manipulation of miR145-5p expression levels. The upregulation of miR145-5p in spinal cord injury (SCI) rats led to a reduction in MAP3K3 protein expression within lung tissues, thereby inhibiting the MAPK/Erk signaling pathway and decreasing apoptosis. Contrarily, rats with miR145-5p knockdown undergoing treadmill training exhibited an increase in miR145-5p expression levels, resulting in the inhibition of MAP3K3 protein expression in lung tissues, suppression of the MAPK/Erk pathway, and mitigation of lung cell apoptosis. Ultimately, the findings suggest that treadmill training may attenuate apoptosis in lung cells post-spinal cord injury by modulating the MAP3K3 protein through miR145-5p to regulate the MAPK/Erk signaling pathway.

Angioarchitecture and genetic variants of spinal cord cavernous malformations and associated developmental venous anomalies: a case report

Cavernous malformations (CM) have long been considered congenital of central nervous system, while the mechanism of CMs detailed development process associated with genetic factors remains unclear. We reported an uncommon case which suffered spinal cord cavernous malformations. In this work, representative samples were obtained, and the sequenced results were described for the first time. A 9-year-old boy was found oblique shoulder with slightly weakness of left limbs; MRI indicated spinal cord cavernous malformations (CMs) located at the C4-C6 vertebral level. On genetic analysis, a shared mutation of PIK3CA (p.H1047R) in CMs and associated developmental venous anomalies (DVAs) was detected, with a different abundance (2% and 7%, respectively), and a somatic mutation of MAP3K3 (p.I441M) was detected in the CM tissue samples. This case provides better knowledge of the formation history and genetic triggers of the DVA-associated CMs. This evidence allows us to speculate the developmental history of the CM lesion: The DVA with PIK3CA mutation might be genetic precursor, and then the associated CM could be derived from terminal cell population of the DVA by acquiring a somatic mutation in MAP3K3.

XJ-8, a natural compound isolated from Sanguis draxonis, inhibits platelet function and thrombosis by targeting MAP3K3

BACKGROUND

Vascular injury initiates rapid platelet activation, which is critical for haemostasis, while it also causes fatal thrombotic diseases, such as myocardial infarction or ischemic stroke.

OBJECTIVES

To study the inhibitory effects and underlying mechanisms of XJ-8, a natural compound isolated from Sanguis draxonis, on platelet activation and thrombosis.

METHODS

The regulatory effects of XJ-8 on the dense granule release, thromboxane A2 (TxA2 ) synthesis, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by multiple agonists were investigated in in vitro experiments. The effects of XJ-8 on bleeding time and FeCl3 -induced carotid artery thrombosis were also evaluated in in vivo experiments. Furthermore, we investigated the underlying mechanisms by which XJ-8 exerted its pharmacological effects.

RESULTS

XJ-8 not only significantly inhibited the dense granule release, TxA2 synthesis, and aggregation of platelets induced by multiple agonists, but also exerted extending effects on bleeding time and therapeutic effects on thrombotic disease. In addition, XJ-8 selectively and moderately inhibited the activity of mitogen-activated protein kinase kinase kinase 3 (MAP3K3) and the activation of signalling pathways downstream MAP3K3, which play important roles in platelet activation.

CONCLUSION

XJ-8 can inhibit platelet function and thrombosis by targeting MAP3K3 and has potential to be developed into a novel therapeutic agent for the treatment of thrombotic diseases.

CircSETDB1 knockdown inhibits the malignant progression of serous ovarian cancer through miR-129-3p-dependent regulation of MAP3K3

Background

Circular RNA (circRNA) is recently found to participate in the regulation of tumor progression, including ovarian cancer. However, the application of circRNA SET domain bifurcated histone lysine methyltransferase 1 (circSETDB1) as a therapeutic target in serous ovarian cancer (SOC) remains to be elucidated. Herein, circSETDB1 role in SOC malignant progression and underlying mechanism are revealed.

Methods

The expression of circSETDB1, microRNA-129-3p (miR-129-3p) and mitogen-activated protein kinase kinase kinase 3 (MAP3K3) messenger RNA (mRNA) was detected by quantitative real-time polymerase chain reaction. Protein abundance was determined by western blot analysis. Cell proliferation, apoptosis, invasion and migration were demonstrated by cell counting kit-8 and 5-Ethynyl-29-deoxyuridine assays, flow cytometry analysis, transwell invasion assay and wound-healing assay, respectively. The interaction between miR-129-3p and circSETDB1 or MAP3K3 was predicted by online database, and identified by mechanism assays. The effect of circSETDB1 knockdown on tumor formation in vivo was unveiled by mouse model experiment.

Results

CircSETDB1 and MAP3K3 expression were apparently upregulated, whereas miR-129-3p expression was downregulated in SOC tissues and cells in comparison with normal fallopian tube tissues or normal ovarian epithelial cells. CircSETDB1 knockdown inhibited cell proliferation, invasion and migration, but induced cell apoptosis in SOC cells. Additionally, miR-129-3p inhibitor impaired circSETDB1 silencing-mediated SOC malignant progression. MiR-129-3p repressed SOC cell processes via binding to MAP3K3. Furthermore, circSETDB1 knockdown suppressed tumor growth in vivo.

Conclusion

CircSETDB1 silencing repressed SOC malignant progression through miR-129-3p/MAP3K3 pathway. This study supports circSETDB1 as a new therapeutic target for SOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-021-00875-0.

1. CircSETDB1 expression was increased in SOC tissues and cells.

2. CircSETDB1 silencing repressed the malignancy of SOC cells.

3. CircSETDB1 mediated SOC malignant progression by interacting with miR-129-3p.

4. MAP3K3 served as a target gene of miR-129-3p.

5. CircSETDB1 knockdown inhibited tumor formation in vivo.

Circ_0006988 promotes the proliferation, metastasis and angiogenesis of non-small cell lung cancer cells by modulating miR-491-5p/MAP3K3 axis

Circular RNAs (circRNAs) are related to the progression of non-small cell lung cancer (NSCLC). However, the roles and mechanism of circ_0006988 are largely unknown. The levels of circ_0006988, Low-Density Lipoprotein Receptor Class A Domain Containing 3 (LDLRAD3), microRNA-491-5p (miR-491-5p), Mitogen-Activated Protein Kinase Kinase Kinase 3 (MAP3K3) were measured using quantitative real-time polymerase-chain reaction (qRT-PCR) and western blot assay. The characteristic of circ_0006988 was analyzed by RNase R assay and Actinomycin D assay. Functional analyses were processed by Cell Counting Kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, flow cytometry analysis, transwell assay, wound-healing assay and tube formation assay. The interactions between circ_0006988 and miR-491-5p as well as miR-491-5p and MAP3K3 were analyzed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Murine xenograft model assay was processed to verify the function of circ_0006988 in vivo. Immunohistochemistry (IHC) assay was conducted to examine the level of Ki67. Circ_0006988 abundance was increased in NSCLC tissues and cells. Circ_0006988 silencing restrained NSCLC cell proliferation, migration, invasion and angiogenesis, and induced apoptosis. Circ_0006988 sponged miR-491-5p, which directly targeted MAP3K3. MiR-491-5p overexpression repressed NSCLC cell malignant behaviors. MiR-491-5p downregulation or MAP3K3 overexpression reversed the effect of circ_0006988 silencing on NSCLC cell progression. In addition, circ_0006988 knockdown reduced xenograft tumor growth. ssCirc_0006988 contributed to the development of NSCLC by miR-491-5p/MAP3K3 axis.

DNM3OS Facilitates Ovarian Cancer Progression by Regulating miR-193a-3p/MAP3K3 Axis

PURPOSE

Long non-coding RNAs (lncRNAs) are essential regulators in the development of ovarian cancer (OC). Nonetheless, the function of lncRNA DNM3 opposite strand/antisense RNA (DNM3OS) in OC remains unclear. This work aimed to investigate the biological roles and underlying mechanisms of DNM3OS in OC.

MATERIALS AND METHODS

Quantitative real-time polymerase chain reaction was conducted to examine DNM3OS, microRNA (miR)-193a-3p, and mitogen-activated protein kinase 3 (MAP3K3) mRNA expression in OC tissues and cell lines. Kaplan-Meier survival analysis was employed to analyze the relationship between DNM3OS expression and the prognosis of OC patients. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine, and transwell experiments were conducted to monitor cell proliferation, migration, and invasion, respectively. Western blot was applied to examine epithelial-mesenchymal transition associated protein (E-cadherin and N-cadherin) expression. Luciferase reporter gene and RNA immunoprecipitation experiments were performed to confirm the relationships among DNM3OS, miR-193a-3p, and MAP3K3. Pearson's correlation analysis was adopted to analyze the correlations among DNM3OS, miR-193a-3p, and MAP3K3 mRNA.

RESULTS

DNM3OS expression was remarkably increased in OC tissues and cell lines, which was associated with the unfavorable prognosis of the patients. DNM3OS overexpression enhanced OC cell proliferation, migration, and invasion; suppressed E-cadherin protein expression; and facilitated N-cadherin protein expression, while the transfection of miR-193a-3p mimics had the opposite effects. DNM3OS directly interacted with miR-193a-3p, and miR-193a-3p targeted MAP3K3 by directly binding to 3'UTR. DNM3OS could up-regulate the expression of MAP3K3 via repressing miR-193a-3p expression.

CONCLUSION

DNM3OS, as an oncogenic lncRNA, increases the malignancy of OC cells via regulation of an miR-193a-3p/MAP3K3 axis.

Concurrent targeting of MAP3K3 and BRD4 by miR-3140-3p overcomes acquired resistance to BET inhibitors in neuroblastoma cells

Neuroblastoma (NB) harboring MYCN amplification is a refractory disease with a poor prognosis. As BRD4, an epigenetic reader belonging to the bromodomain and extra terminal domain (BET) family, drives transcription of MYCN in NB cells, BET inhibitors (BETis) are considered useful for NB therapy. However, clinical trials of BETis suggested that early acquired resistance to BETis limits their therapeutic benefit. MicroRNAs are small non-coding RNAs that mediate post-transcriptional silencing of target genes. We previously identified miR-3140-3p as a potent candidate for nucleic acid therapeutics for cancer, which directly targets BRD4. We demonstrated that miR-3140-3p suppresses tumor cell growth in MYCN-amplified NB by downregulating MYCN and MYC through BRD4 suppression. We established BETi-acquired resistant NB cells to evaluate the mechanism of resistance to BETi in NB cells. We revealed that activated ERK1/2 stabilizes MYCN protein by preventing ubiquitin-mediated proteolysis via phosphorylation of MYCN at Ser62 in BETi-acquired resistant NB cells, thereby attenuating the effects of BETi in these cells. miR-3140-3p efficiently downregulated MYCN expression by directly targeting the MAP3K3-ERK1/2 pathway in addition to BRD4 suppression, inhibiting tumor cell growth in BETi-acquired resistant NB cells. This study suggests that miR-3140-3p has the potential to overcome resistance to BETi in NB.

Somatic MAP3K3 mutation defines a subclass of cerebral cavernous malformation

Cerebral cavernous malformations (CCMs) are vascular disorders that affect up to 0.5% of the total population. About 20% of CCMs are inherited because of familial mutations in CCM genes, including CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10, whereas the etiology of a majority of simplex CCM-affected individuals remains unclear. Here, we report somatic mutations of MAP3K3, PIK3CA, MAP2K7, and CCM genes in CCM lesions. In particular, somatic hotspot mutations of PIK3CA are found in 11 of 38 individuals with CCMs, and a MAP3K3 somatic mutation (c.1323C>G [p.Ile441Met]) is detected in 37.0% (34 of 92) of the simplex CCM-affected individuals. Strikingly, the MAP3K3 c.1323C>G mutation presents in 95.7% (22 of 23) of the popcorn-like lesions but only 2.5% (1 of 40) of the subacute-bleeding or multifocal lesions that are predominantly attributed to mutations in the CCM1/2/3 signaling complex. Leveraging mini-bulk sequencing, we demonstrate the enrichment of MAP3K3 c.1323C>G mutation in CCM endothelium. Mechanistically, beyond the activation of CCM1/2/3-inhibited ERK5 signaling, MEKK3 p.Ile441Met (MAP3K3 encodes MEKK3) also activates ERK1/2, JNK, and p38 pathways because of mutation-induced MEKK3 kinase activity enhancement. Collectively, we identified several somatic activating mutations in CCM endothelium, and the MAP3K3 c.1323C>G mutation defines a primary CCM subtype with distinct characteristics in signaling activation and magnetic resonance imaging appearance.

Somatic MAP3K3 and PIK3CA mutations in sporadic cerebral and spinal cord cavernous malformations

Cavernous malformations (CMs) affecting the central nervous system occur in approximately 0.16% to 0.4% of the general population. The majority (85%) of the CMs are in a sporadic form, but the genetic background of sporadic CMs remains enigmatic. Of the 81 patients, 73 (90.1%) patients were detected carrying somatic missense variants in 2 genes: MAP3K3 and PIK3CA by whole-exome sequencing (WES). The mutation spectrum correlated with lesion size (P = 0.001), anatomical distribution (P < 0.001), MRI appearance (P = 0.004) and haemorrhage events (P = 0.006). PIK3CA mutation was a significant predictor of overt haemorrhage events (P = 0.003, OR = 11.252, 95% CI = 2.275-55.648). Enrichment of endothelial cell (EC) population was associated with a higher fractional abundance of the somatic mutations. Overexpression of the MAP3K3 mutation perturbed angiogenesis of EC models in vitro and zebrafish embryos in vivo. Distinct transcriptional signatures between different genetic subgroups of sporadic CMs were identified by single-cell RNA-sequencing (scRNA-seq) and verified by pathological staining. Significant apoptosis in MAP3K3 mutation carriers and overexpression of GDF15 and SERPINA5 in PIK3CA mutation carriers contributed to their phenotype. We identified activating MAP3K3 and PIK3CA somatic mutations in the majority (90.1%) of sporadic CMs and PIK3CA mutations could confer a higher risk for overt haemorrhage. Our data provide insights into genomic landscapes, propose a mechanistic explanation and underscore the possibility of a molecular classification for sporadic CMs.

Late-onset multiple venous malformations confined to the upper limb: link to somatic MAP3K3 mutations

Venous (cavernous) malformations are commonly seen in the upper limb. Almost all venous malformations are congenital. They may be sporadic, familial, or syndromic. Late-onset, multiple venous malformations confined to the upper limb are rare. Lesions present after puberty. All previously reported cases were located subcutaneously and were small in size. The condition is non-hereditary and non-syndromic. We present a unique series of eight patients with this rare condition. Unique features included the presence of large malformations (up to 20 cm in diameter) and the presence of subfascial lesions causing nerve compression. Surgical excision was curative. Mutational analysis in one patient identified a novel somatic MAP3K3 gene mutation (c.1723T > C, p.Tyr 575 His) in the affected veins. The encoded MAP3K3 protein is known to accelerate the RAS pathway of cellular proliferation.Level of evidence: IV.

BECN2 (beclin 2)-mediated non-canonical autophagy in innate immune signaling and tumor development

BECN2 (beclin 2) is a newly identified mammalian-specific macroautophagy/autophagy family member, and plays a critical role in the control of obesity and insulin sensitivity. However, its role in innate immune signaling and inflammation remains elusive. In our recent study, we show that BECN2 functions as a negative regulator in innate immune signaling and tumor development through non-canonical autophagy. Loss of Becn2 causes splenomegaly, lymphadenopathy, elevated proinflammatory cytokine production and spontaneous lymphoma development in mice. Mechanistically, BECN2 mediates the degradation of MAP3K7/TAK1 and MAP3K3/MEKK3 through an ATG9A- and ULK1-dependent but ATG16L1-BECN1-MAP1LC3B/LC3B-independent autophagy pathway to control systemic inflammation. BECN2 interacts with MAP3K7 and MAP3K3 through the engagement of ATG9A⁺ vesicles upon ULK1 activation, and promotes the fusion of MAP3K3- or MAP3K7-associated ATG9A⁺ vesicles with phagophores for subsequent degradation. Our findings have identified a previously unrecognized role of BECN2 in innate immune signaling and tumor development through non-canonical autophagy, thus providing a potential target for inflammatory disease and cancer therapy.

MiR-212-3p suppresses high-grade serous ovarian cancer progression by directly targeting MAP3K3

MicroRNAs (miRNAs) are small regulatory non-coding RNAs that have been reported to play an important role in the tumorigenesis of many cancers. In addition, miRNAs might serve as new promising biomarkers for diagnosis and prognosis and as effective therapeutic targets for patients with such malignancies. Accordingly, the dysregulation of miR-212-3p has been reported in a variety of human cancers. However, its biological functions and molecular mechanisms high-grade serous ovarian cancer (HGSOG) remain unknown. In this study, we demonstrated that miR-212-3p interacts with MAP3K3 based on bioinformatics-based predictions. Further, MAP3K3 was identified as a direct target gene of miR-212-3p in HGSOC. In addition, overexpression of miR-212-3p in HGSOC inhibited cell proliferation, colony formation, invasion, and migration. In contrast MAP3K3 mitigated the suppressive effects of miR-212-3p on HGSOC cell proliferation, invasion, and migration. Furthermore, miR-212-3p was significantly downregulated in HGSOC tissues compared to expression in normal fallopian tube tissues and was inversely associated with MAP3K3 levels. Accordingly, low miR-212-3p expression was also correlated with poor prognosis for HGSOC patients. In conclusion, miR-212-3p might act as a suppressor of HGSOC carcinogenesis by directly targeting MAP3K3. Therefore, this miRNA could be a novel and effective target for the treatment of patients with HGSOC.

Long non-coding RNA CDKN2B-AS1 promotes osteosarcoma by increasing the expression of MAP3K3 via sponging miR-4458

Osteosarcoma (OS) is the most common primary malignant bone tumor worldwide. Recently, several studies have shown that the long non-coding RNA (lncRNA) CDKN2B-AS1 plays a critical role in several cancers. However, the function and underlying mechanism of CDKN2B-AS1 in OS development remains elusive. In this study, we firstly assessed the expression of CDKN2B-AS1 in OS tissues and cells, showing that CDKN2B-AS1 expression were remarkably upregulated in OS tissues and cells. Moreover, CDKN2B-AS1 knockdown suppressed cell proliferation, migration, and EMT progress in OS. Interestingly, we found and proved that CDKN2B-AS1 could sponge miR-4458 in OS cells. Moreover, MAP3K3 was certified as a downstream target of miR-4458 in OS. Besides, MAP3K3 was negatively regulated by miR-4458 and positively regulated by CDKN2B-AS1. More importantly, overexpression of MAP3K3 could partly counteract the effect of CDKN2B-AS1 suppression on the biological behavior of OS cells. Also, the in vivo experiments further testified that CDKN2B-AS1 accelerated tumor growth in OS. Our results suggested that CDKN2B-AS1 facilitated OS progression by sponging miR-4458 to enhance MAP3K3 expression, which provides a novel insight into improving diagnostic and therapeutic strategies for patients with OS.

MiR-194 regulates nasopharyngeal carcinoma progression by modulating MAP3K3 expression

Despite the recent development of treatment strategies for nasopharyngeal carcinoma, the effective management of this disease remains a challenging clinical problem. A better understanding of the regulatory roles of miR‐194 and mitogen‐activated protein kinase kinase kinase 3 (MAP3K3) in the nasopharyngeal‐carcinoma‐related gene network is required to address this issue. Here, we measured relative expression of miR‐194 in human nasopharyngeal carcinoma tissues and normal epithelial tissues by quantitative real time PCR. We transfected cultured CNE‐1 and C666‐1 cells with miR‐194 mimics, and then examined the effects on cell proliferation, cell migration and invasion. Luciferase reporter assay was used to validate the putative binding between miR‐194 and MAP3K3. We then examined the effect of knockdown and overexpression of MAP3K3 on cell tumorigenesis. Expression of miR‐194 is significantly down‐regulated in nasopharyngeal carcinoma specimens and tumor cell lines when compared with normal controls. In addition, miR‐194 suppressed tumor cell proliferation and viability, as well as migration and invasion of carcinoma cells. We found that miR‐194 binds the 3′ untranslated region of MAP3K3, and knockdown of miR‐194 inhibited nasopharyngeal carcinoma cell proliferation, migration and invasion. In accordance, overexpression of MAP3K3 reversed the inhibitory effects of miR‐194 in carcinoma cells. This study suggests that expression of miR‐194 is down‐regulated in nasopharyngeal carcinoma, and that miR‐194 can directly target MAP3K3 to regulate tumor progression. Given the pivotal involvement of MAP3K3 in nasopharyngeal carcinoma development, targeting miR‐194 may be a novel strategy for the treatment of nasopharyngeal carcinoma.

MiroRNA-188 Acts as Tumor Suppressor in Non-Small-Cell Lung Cancer by Targeting MAP3K3

Non-small cell lung cancer (NSCLC) is the most prevalent form of lung cancer. MicroRNAs have been increasingly implicated in NSCLC and may serve as novel therapeutic targets to combat cancer. Here we investigated the functional implication of miR-188 in NSCLC. We first analyzed miR-188 expression in both NSCLC clinical samples and cancer cell lines. Next we investigated its role in A549 and H2126 cells with cell proliferation, migration, and apoptosis assays. To extend the in vitro study, we employed both xenograft model and LSL- K-ras G12D lung cancer model to examine the role of miR-188 in tumorigenesis. Last we tested MAP3K3 as miR-188 target in NSCLC model. MiR-188 expression was significantly downregulated at the NSCLC tumor sites and lung cancer cells. In vitro transfection of miR-188 reduced cell proliferation and migration potential and promoted cell apoptosis. In xenograft model, miR-188 inhibited tumor growth derived from cancer cells. Intranasal miR-188 administration reduced tumor formation in NSCLC animal model. MAP3K3 was validated as direct target of miR-188. Knocking down MAP3K3 in mice also inhibited tumorigenesis in LSL- K-ras G12D model. Our results demonstrate that miR-188 and its downstream target MAP3K3 could be a potential therapeutic target for NSCLC.

MAP3K3 overexpression is associated with poor survival in ovarian carcinoma

Mitogen-activated protein kinase kinase kinase 3 (MAP3K3) is ubiquitously expressed in numerous tissues and is activated by various extracellular stimuli to regulate processes, such as cell proliferation and differentiation. Recent studies have identified potentially pathologic conditions of MAP3K3 as an oncogene that promotes tumor progression and metastasis in a number of malignancies. However, the clinical significance of MAP3K3 expression in ovarian carcinoma (OC) remains unclear. In this study, the correlation between MAP3K3 expression and OC prognosis was assessed by immunohistochemistry. MAP3K3 overexpression was observed in 59.1% (55/93) of OCs and was significantly associated with histological type and grade, chemotherapy response, and challenge model (P < .05, respectively). MAP3K3 overexpression was also used as an independent prognostic marker for decreased disease-free survival and overall survival. In OC cell lines, MAP3K3 expression was evaluated by Western blot analysis, quantitative real-time polymerase chain reaction, and immunofluorescence. High MAP3K3 expression is significantly detected in SKOV3, C13*, and A2780 cells. All these findings suggested that MAP3K3 overexpression is an independent poor prognostic indicator of OC and can be a clinically effective biomarker of OC.

microRNA-122 regulates hypoxia-inducible factor-1 and vimentin in hepatocytes and correlates with fibrosis in diet-induced steatohepatitis

BACKGROUND & AIMS

miR-122 is the most abundant miRNA in the liver particularly in hepatocytes where it targets cholesterol metabolism. Steatosis, a key component of non-alcoholic fatty liver disease, is regulated by hypoxia-inducible factor-1α (HIF-1α). Here, we hypothesized that reduced miR-122 has a pathogenic role in steatohepatitis.

METHODS

miR-122 and its target genes were evaluated in mouse livers and/or isolated hepatocytes after methionine-choline-deficient (MCD) or methionine-choline-supplemented (MCS) diet.

RESULTS

Liver and hepatocyte miR-122 expression was significantly decreased in steatohepatitis. A maximum reduction in miR-122 occurred at the fibrosis stage (8 weeks of MCD diet). MAP3K3, a miR-122 target gene, was induced at all stages of non-alcoholic steatohepatitis (NASH; 3-8 weeks) only at the mRNA level. Increased NF-κB activation was found in MCD diet-fed mice and MAP3K3 regulated the NF-κB DNA binding in naive hepatocytes. HIF-1α mRNA and DNA binding and expression of the HIF-1α target gene, profibrotic lysyl oxidase, was increased in advanced steatohepatitis (8 weeks). In addition, increase in vimentin and Sirius red staining (liver fibrosis) was found at 8 weeks of MCD diet. Using miR-122 overexpression and inhibition approaches, we confirmed that HIF-1α, vimentin and MAP3K3 are novel miR-122 targets in hepatocytes. We report transcriptional repression of miR-122 in NASH. Decreased liver miR-122 was associated with elevated circulating miR-122 in both exosome-rich and protein-rich serum fractions.

CONCLUSIONS

Our novel data suggest that decreased liver miR-122 contributes to upregulation of modulators of tissue remodelling (HIF-1α, vimentin and MAP3K3) and might play a role in NASH-induced liver fibrosis.

Amplification and over-expression of MAP3K3 gene in human breast cancer promotes formation and survival of breast cancer cells

Gene amplifications in the 17q chromosomal region are observed frequently in breast cancers. An integrative bioinformatics analysis of this region nominated the MAP3K3 gene as a potential therapeutic target in breast cancer. This gene encodes mitogen-activated protein kinase kinase kinase 3 (MAP3K3/MEKK3), which has not yet been reported to be associated with cancer-causing genetic aberrations. We found that MAP3K3 was amplified in approximately 8-20% of breast cancers. Knockdown of MAP3K3 expression significantly inhibited cell proliferation and colony formation in MAP3K3-amplified breast cancer cell lines MCF-7 and MDA-MB-361 but not in MAP3K3 non-amplified breast cancer cells. Knockdown of MAP3K3 expression in MAP3K3-amplified breast cancer cells sensitized breast cancer cells to apoptotic induction by TNFα and TRAIL, as well as doxorubicin, VP-16 and fluorouracil, three commonly used chemotherapeutic drugs for treating breast cancer. In addition, ectopic expression of MAP3K3, in collaboration with Ras, induced colony formation in both primary mouse embryonic fibroblasts and immortalized human breast epithelial cells (MCF-10A). Combined, these results suggest that MAP3K3 contributes to breast carcinogenesis and may endow resistance of breast cancer cells to cytotoxic chemotherapy. Therefore, MAP3K3 may be a valuable therapeutic target in patients with MAP3K3-amplified breast cancers, and blocking MAP3K3 kinase activity with a small molecule inhibitor may sensitize MAP3K3-amplified breast cancer cells to chemotherapy.