A RING to rule them all? Insights into the Map3k1 PHD motif provide a new mechanistic understanding into the diverse roles of Map3k1

PhenoDriver: interpretable framework for studying personalized phenotype-associated driver genes in breast cancer

Identifying personalized cancer driver genes and further revealing their oncogenic mechanisms is critical for understanding the mechanisms of cell transformation and aiding clinical diagnosis. Almost all existing methods primarily focus on identifying driver genes at the cohort or individual level but fail to further uncover their underlying oncogenic mechanisms. To fill this gap, we present an interpretable framework, PhenoDriver, to identify personalized cancer driver genes, elucidate their roles in cancer development and uncover the association between driver genes and clinical phenotypic alterations. By analyzing 988 breast cancer patients, we demonstrate the outstanding performance of PhenoDriver in identifying breast cancer driver genes at the cohort level compared to other state-of-the-art methods. Otherwise, our PhenoDriver can also effectively identify driver genes with both recurrent and rare mutations in individual patients. We further explore and reveal the oncogenic mechanisms of some known and unknown breast cancer driver genes (e.g. TP53, MAP3K1, HTT, etc.) identified by PhenoDriver, and construct their subnetworks for regulating clinical abnormal phenotypes. Notably, most of our findings are consistent with existing biological knowledge. Based on the personalized driver profiles, we discover two existing and one unreported breast cancer subtypes and uncover their molecular mechanisms. These results intensify our understanding for breast cancer mechanisms, guide therapeutic decisions and assist in the development of targeted anticancer therapies.

JNK Cascade-Induced Apoptosis-A Unique Role in GqPCR Signaling

The response of cells to extracellular signals is mediated by a variety of intracellular signaling pathways that determine stimulus-dependent cell fates. One such pathway is the cJun-N-terminal Kinase (JNK) cascade, which is mainly involved in stress-related processes. The cascade transmits its signals via a sequential activation of protein kinases, organized into three to five tiers. Proper regulation is essential for securing a proper cell fate after stimulation, and the mechanisms that regulate this cascade may involve the following: (1) Activatory or inhibitory phosphorylations, which induce or abolish signal transmission. (2) Regulatory dephosphorylation by various phosphatases. (3) Scaffold proteins that bring distinct components of the cascade in close proximity to each other. (4) Dynamic change of subcellular localization of the cascade's components. (5) Degradation of some of the components. In this review, we cover these regulatory mechanisms and emphasize the mechanism by which the JNK cascade transmits apoptotic signals. We also describe the newly discovered PP2A switch, which is an important mechanism for JNK activation that induces apoptosis downstream of the Gq protein coupled receptors. Since the JNK cascade is involved in many cellular processes that determine cell fate, addressing its regulatory mechanisms might reveal new ways to treat JNK-dependent pathologies.

NOTCH Signaling Limits the Response of Low-Grade Serous Ovarian Cancers to MEK Inhibition

Low-grade serous ovarian cancer (LGSOC) is a rare subtype of epithelial ovarian cancer with high fatality rates in advanced stages due to its chemoresistant properties. LGSOC is characterized by activation of MAPK signaling, and recent clinical trials indicate that the MEK inhibitor (MEKi) trametinib may be a good treatment option for a subset of patients. Understanding MEKi-resistance mechanisms and subsequent identification of rational drug combinations to suppress resistance may greatly improve LGSOC treatment strategies. Both gain-of-function and loss-of-function CRISPR-Cas9 genome-wide libraries were used to screen LGSOC cell lines to identify genes that modulate the response to MEKi. Overexpression of MAML2 and loss of MAP3K1 were identified, both leading to overexpression of the NOTCH target HES1, which has a causal role in this process as its knockdown reversed MEKi resistance. Interestingly, increased HES1 expression was also observed in selected spontaneous trametinib-resistant clones, next to activating MAP2K1 (MEK1) mutations. Subsequent trametinib synthetic lethality screens identified SHOC2 downregulation as being synthetic lethal with MEKis. Targeting SHOC2 with pan-RAF inhibitors (pan-RAFis) in combination with MEKi was effective in parental LGSOC cell lines, in MEKi-resistant derivatives, in primary ascites cultures from patients with LGSOC, and in LGSOC (cell line-derived and patient-derived) xenograft mouse models. We found that the combination of pan-RAFi with MEKi downregulated HES1 levels in trametinib-resistant cells, providing an explanation for the synergy that was observed. Combining MEKis with pan-RAFis may provide a promising treatment strategy for patients with LGSOC, which warrants further clinical validation.

Neurodevelopmental disorders, immunity, and cancer are connected

Immunity could be viewed as the common factor in neurodevelopmental disorders and cancer. The immune and nervous systems coevolve as the embryo develops. Immunity can release cytokines that activate MAPK signaling in neural cells. In specific embryonic brain cell types, dysregulated signaling that results from germline or embryonic mutations can promote changes in chromatin organization and gene accessibility, and thus expression levels of essential genes in neurodevelopment. In cancer, dysregulated signaling can emerge from sporadic somatic mutations during human life. Neurodevelopmental disorders and cancer share similarities. In neurodevelopmental disorders, immunity, and cancer, there appears an almost invariable involvement of small GTPases (e.g., Ras, RhoA, and Rac) and their pathways. TLRs, IL-1, GIT1, and FGFR signaling pathways, all can be dysregulated in neurodevelopmental disorders and cancer. Although there are signaling similarities, decisive differentiating factors are timing windows, and cell type specific perturbation levels, pointing to chromatin reorganization. Finally, we discuss drug discovery.

Pathogenic Variants in MAP3K1 Cause 46,XY Gonadal Dysgenesis: A Review

Pathogenic variants in the MAP3K1 gene are an important cause of 46,XY non-syndromic partial and complete gonadal dysgenesis, accounting for at least 4% of cases. Inheritance occurs in a sex-limited, autosomal dominant fashion with virtually complete penetrance in 46,XY individuals. 46,XX carriers appear to have normal fertility and no developmental abnormalities. Pathogenic variants occur almost exclusively within known domains of the MAP3K1 protein, facilitating annotation when identified. Where studied, these variants have been modeled to alter the local MAP3K1 folding and surface domains and have been shown to alter interactions with known binding partners. The net effect of these variants is to increase phosphorylation of downstream targets ERK1, ERK2, and p38, resulting in multiple gain-of-function effects interfering with testis determination and enabling ovarian determination.

The Integrated "Multiomics" Landscape at Peak Injury and Resolution From Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) is a significant clinical problem for which the most effective therapy is alcohol abstinence. The two aims of this study were, first, to identify the liver transcriptome, fecal microbiome, and portal serum metabolome at peak injury and during early and late resolution from ALD; and second, to integrate their interactions and understand better the pathogenesis of ALD. To provoke alcohol-induced liver injury, female and male wild-type mice were fed the control or ethanol Lieber-DeCarli diets for 6 weeks. To study early and late resolution, alcohol was withdrawn from the diet and mice were sacrificed after 3 and 14 days, respectively. At peak injury, there was increased signal transducer and activator of transcription (Stat3), Rho-GTPases, Tec kinase and glycoprotein VI (Gp6), and decreased peroxisome proliferator-activated receptor signaling. During resolution from ALD, there was up-regulation of vitamin D receptor/retinoid X receptor, toll-like receptor, p38 and Stat3, and down-regulation of liver X receptor signaling. Females showed significant changes in catabolic pathways, whereas males increased cellular stress, injury, and immune-response pathways that decreased during resolution. The bacterial genus Alistipes and the metabolite dipeptide glycyl-L-leucine increased at peak but decreased during resolution from ALD in both genders. Hepatic induction of mitogen-activated protein kinase (Map3k1) correlated with changes in the microbiome and metabolome at peak but was restored during ALD resolution. Inhibition of MAP3K1 protected from ALD in mice. Conclusion: Alcohol abstinence restores the liver transcriptome, fecal microbiome, and portal serum metabolome in a gender-specific manner. Integration of multiomics data identified Map3k1 as a key gene driving pathogenesis and resolution from ALD.

Implementation of Clinical Phosphoproteomics and Proteomics for Personalized Medicine

The identification of biomarkers for companion diagnostics is revolutionizing the development of treatments tailored to individual patients in different disease areas including cancer. Precision medicine is most frequently based on the detection of genomic markers that correlate with the efficacy of selected targeted therapies. However, since nongenetic mechanisms also contribute to disease biology, there is a considerable interest of using proteomic techniques as additional source of biomarkers to personalize therapies. In this chapter, we describe label-free mass spectrometry methods for proteomic and phosphoproteomic analysis compatible with routine analysis of clinical samples. We also outline bioinformatic pipelines based on statistical learning that use these proteomics datasets as input to quantify kinase activities and predict drug responses in cancer cells.

A MEKK1 - JNK mitogen activated kinase (MAPK) cascade module is active in Echinococcus multilocularis stem cells

Background

The metacestode larval stage of the fox-tapeworm Echinococcus multilocularis causes alveolar echinococcosis by tumour-like growth within the liver of the intermediate host. Metacestode growth and development is stimulated by host-derived cytokines such as insulin, fibroblast growth factor, and epidermal growth factor via activation of cognate receptor tyrosine kinases expressed by the parasite. Little is known, however, concerning signal transmission to the parasite nucleus and cross-reaction with other parasite signalling systems.

Methodology/Principal findings

Using bioinformatic approaches, cloning, and yeast two-hybrid analyses we identified a novel mitogen-activated kinase (MAPK) cascade module that consists of E. multilocularis orthologs of the tyrosine kinase receptor interactor Growth factor receptor-bound 2, EmGrb2, the MAPK kinase kinase EmMEKK1, a novel MAPK kinase, EmMKK3, and a close homolog to c-Jun N-terminal kinase (JNK), EmMPK3. Whole mount in situ hybridization analyses indicated that EmMEKK1 and EmMPK3 are both expressed in E. multilocularis germinative (stem) cells but also in differentiated or differentiating cells. Treatment with the known JNK inhibitor SP600125 led to a significantly reduced formation of metacestode vesicles from stem cells and to a specific reduction of proliferating stem cells in mature metacestode vesicles.

Conclusions/Significance

We provide evidence for the expression of a MEKK1-JNK MAPK cascade module which, in mammals, is crucially involved in stress responses, cytoskeletal rearrangements, and apoptosis, in E. multilocularis stem cells. Inhibitor studies indicate an important role of JNK signalling in E. multilocularis stem cell survival and/or maintenance. Our data are relevant for molecular and cellular studies into crosstalk signalling mechanisms that govern Echinococcus stem cell function and introduce the JNK signalling cascade as a possible target of chemotherapeutics against echinococcosis.

The metacestode larva of the tapeworm E. multilocularis grows infiltrative, like a malignant tumour, within the liver of the host thus causing the lethal disease alveolar echinococcosis. Previous work established that the metacestode senses signals of host hormones and cytokines by expressing surface receptors that share high homology with respective host receptors. However, little is known how these signals are transmitted from the parasite cell surface to the nucleus to alter gene expression. In this work, the authors present a module of several protein kinases that typically transmit cytokine signals from surface receptors to central regulators called mitogen-activated protein kinases (MAPK). The authors demonstrate that this module is active in parasite stem cells, which drive the development of metacestode larva. They also show that inhibitors directed against one component of the module, EmMPK3, affect maintenance and/or survival of stem cells in the metacestode and prevent the formation of metacestode larva from parasite cell cultures. This information facilitates molecular and cellular studies to unravel the complex signalling network that regulate Echinococcus stem cell proliferation in response to host signals. Furthermore, these data could open new ways of anti-parasitic chemotherapy by introducing EmMPK3 as a possible drug target.

Inhibition of circ_0081234 reduces prostate cancer tumor growth and metastasis via miR-1/MAP3K1 axis

INTRODUCTION

Circular RNAs (circRNAs) are crucial regulators in tumor occurrence and progression, and circRNAs are enriched and stable in exosomes. This study aimed to explore the role and potential mechanism of cancer-derived exosomal circ_0081234 in prostate cancer (PCa).

METHODS

Exosomes were extracted using the ExoQuick Precipitation Kit. The levels of circ_0081234, miR-1 and mitogen-activated protein kinase kinase kinase 1 (MAP 3K1) were examined using qRT-PCR or western blot. Cell migration and invasion were evaluated via transwell assay. The protein levels of N-cadherin, Vimentin and E-cadherin were detected by western blot. The interaction between miR-1 and circ_0081234 or MAP 3K1 was verified via dual-luciferase reporter assay and RNA pull-down assay.

RESULTS

Circ_0081234 level was increased in PC a tissues with spinal metastasis (SM) in comparison to primary PCa tissues without SM. Exosomal circ_0081234 promoted the migration, invasion and epithelial-mesenchymal transition (EMT) of PCa cells. Knockdown of circ_0081234 blocked PCa cell progression via regulating miR-1. In addition, miR-1 overexpression suppressed PCa cell progression by repressing MAP 3K1. Moreover, circ_0081234 increased MAP 3K1 level via sponging miR-1. Depletion of circ_0081234 inhibited tumor growth in vivo.

CONCLUSION

Exosomal circ_0081234 promoted migration, invasion and EMT of PCa cells by regulating the miR-1/MAP 3K1 axis.

Silencing MAP3K1 expression inhibits the proliferation of goat hair follicle stem cells

The Yangtze River Delta White Goat is the only goat breed in the world that can produce superior-quality brush hair. Previous studies have shown that some genes are expressed differentially in the skin tissues between the goats produced superior-quality and normal-quality brush hair. Studies also have shown that different gene play varied roles in regulating the proliferation and apoptosis of hair follicle stem cells. However, the biological function of MAP3K1 (mitogen-activated protein kinase kinase kinase 1) gene in hair follicle stem cells is not fully understood. This study aims to investigate the role of MAP3K1 knockdown during the proliferation and apoptosis of hair follicle stem cells. RT-qPCR and Western blot were used to detect mRNA gene and protein expression level, CCK-8 and EdU assays were used to detect cell proliferation, and cell cycle and apoptosis were detected by flow cytometry. The results showed that the MAP3K1 expression level was significantly higher in the skin tissue of produced superior-quality brush hair than that in produced normal-quality brush hair. Moreover, functional studies indicated that si-MAP3K1 significantly inhibits the proliferation of hair follicle stem cells that came from a superior goat and promotes its apoptosis. Based on aforementioned assays, we speculated that MAP3K1 might play a regulatory effect in superior-quality brush hair traits.

Association Study of MAP3K1 SNPs and Risk Factors with Susceptibility to Esophageal Squamous Cell Carcinoma in a Chinese Population: A Case-Control Study

Purpose

The aim of this study was to screen the predisposed population and explore possible interactions between genetic polymorphisms and risk factors involved in the tumorigenesis and progression of ESCC (esophageal squamous cell carcinoma), in hope of identifying possible therapeutic targets along the way.

Patients and Methods

Cases (1043) and controls (1315) were enrolled to evaluate the possible association between MAP3K1 SNPs and ESCC risk. Subgroup analyses include MAP3K1 variants, gender, age, smoking and drinking status.

Results

Among all three single locus polymorphisms of MAP3K1, only the heterozygote genotype of rs702689 AG is shown to be associated with increased risk for developing ESCC (OR=1.272, 95% confidence interval=1.061–1.525, p=0.009). Moreover, stratified analysis results observed altered susceptibility among patients with exposure to risk factors combined with certain genetic variant to ESCC.

Conclusion

This study reveals that MAP3K1 rs702689 AG genotype might facilitate the tumorigenesis in ESCC, particularly among women, patients who were over 63y and those who never drink nor smoke.

The Oviductal Extracellular Vesicles' RNA Cargo Regulates the Bovine Embryonic Transcriptome

Oviductal extracellular vesicles (oEVs) are emerging as key players in the gamete/embryo–oviduct interactions that contribute to successful pregnancy. Various positive effects of oEVs on gametes and early embryos have been found in vitro. To determine whether these effects are associated with changes of embryonic gene expression, the transcriptomes of embryos supplemented with bovine fresh (FeEVs) or frozen (FoEVs) oEVs during in vitro culture compared to controls without oEVs were analyzed by low-input RNA sequencing. Analysis of RNA-seq data revealed 221 differentially expressed genes (DEGs) between FoEV treatment and control, 67 DEGs for FeEV and FoEV treatments, and minor differences between FeEV treatment and control (28 DEGs). An integrative analysis of mRNAs and miRNAs contained in oEVs obtained in a previous study with embryonic mRNA alterations pointed to direct effects of oEV cargo on embryos (1) by increasing the concentration of delivered transcripts; (2) by translating delivered mRNAs to proteins that regulate embryonic gene expression; and (3) by oEV-derived miRNAs which downregulate embryonic mRNAs or modify gene expression in other ways. Our study provided the first high-throughput analysis of the embryonic transcriptome regulated by oEVs, increasing our knowledge on the impact of oEVs on the embryo and revealing the oEV RNA components that potentially regulate embryonic development.

Mutations in MAP3K1 that cause 46,XY disorders of sex development disrupt distinct structural domains in the protein

Missense mutations in the gene, MAP3K1, are a common cause of 46,XY gonadal dysgenesis, accounting for 15-20% of cases [Ostrer, 2014, Disorders of sex development (DSDs): an update. J. Clin. Endocrinol. Metab., 99, 1503-1509]. Functional studies demonstrated that all of these mutations cause a protein gain-of-function that alters co-factor binding and increases phosphorylation of the downstream MAP kinase pathway targets, MAPK11, MAP3K and MAPK1. This dysregulation of the MAP kinase pathway results in increased CTNNB1, increased expression of WNT4 and FOXL2 and decreased expression of SRY and SOX9. Unique and recurrent pathogenic mutations cluster in three semi-contiguous domains outside the kinase region of the protein, a newly identified N-terminal domain that shares homology with the Guanine Exchange Factor (residues Met164 to Glu231), a Plant HomeoDomain (residues Met442 to Trp495) and an ARMadillo repeat domain (residues Met566 to Glu862). Despite the presence of the mutation clusters and clinical data, there exists a dearth of mechanistic insights behind the development imbalance. In this paper, we use structural modeling and functional data of these mutations to understand alterations of the MAP3K1 protein and the effects on protein folding, binding and downstream target phosphorylation. We show that these mutations have differential effects on protein binding depending on the domains in which they occur. These mutations increase the binding of the RHOA, MAP3K4 and FRAT1 proteins and generally decrease the binding of RAC1. Thus, pathologies in MAP3K1 disrupt the balance between the pro-kinase activities of the RHOA and MAP3K4 binding partners and the inhibitory activity of RAC1.

Transcriptome analysis of MAPK signaling pathway and associated genes to angiogenesis in chicken erythrocytes on response to thiram-induced tibial lesions

This study was planned to investigate TD (Tibial dyschondroplasia) on the potential MAPK signaling pathway and angiogenesis related genes. Forty-eight broilers were allotted into control (C) and treatment (T) groups of 2, 6 and 15 days as C1, C2, C3, T1, T2 and T3. The histopathology results revealed that tibiotarsus bone of chickens had more lesions on day 6 (T2 group). The chondrocytes were disordered, and the size, shape and proliferation were affected. Transcriptome results revealed that differentially expressed genes (DEGs) identified were 63, 1026, 623, 130, 141 and 146 in C1 (2 days control vs 6 days control); C2 (2 days control vs 15 days control); C3 (6 days control vs 15 days control); T1 (2 days treatment vs 6 days treatment); T2 (2 days treatment vs 15 days treatment) and T3 (6 days treatment vs 15 days treatment) groups respectively. Whereas, 10 angiogenesis related-genes RHOC, MEIS2, BAIAP2, TGFBI, KLF2, CYR61, PTPN11, PLXNC1, HSPH1 and NRP2 were downregulated on day 6 in the treatment group. The pathway which was found enriched in the control and treatment groups was MAPK signaling pathway. Therefore selected 10 MAPK signaling pathway-related genes RAC2, MAP3K1, PRKCB, FLNB, IL1R1, PTPN7, RPS6KA, MAP3K6, GNA12 and HSPA8 which were found significantly downregulated in the treatment group on day 6. It is concluded that angiogenesis and MAPK signaling pathway related genes has an essential role in TD, as those top screened genes found downregulated in the thiram fed chickens when TD observed severed on day 6.

Gene expression profiling of the early pathogenesis of wooden breast disease in commercial broiler chickens using RNA-sequencing

Wooden Breast Disease (WBD), a myopathy in commercial broiler chickens characterized by abnormally firm consistency of the pectoral muscle, impacts the poultry industry negatively due to severe reduction in meat quality traits. To unravel the molecular profile associated with the onset and early development of WBD in broiler chickens, we compared time-series gene expression profiles of Pectoralis (P.) major muscles between unaffected and affected birds from a high-breast-muscle-yield, purebred broiler line. P. major biopsy samples were collected from the cranial and caudal aspects of the muscle belly in birds that were raised up to 7 weeks of age (i.e. market age). Three subsets of biopsy samples comprising 6 unaffected (U) and 10 affected (A) from week 2 (cranial) and 4 (caudal), and 4U and 11A from week 3 (cranial) were processed for RNA-sequencing analysis. Sequence reads generated were processed using a suite of bioinformatics programs producing differentially expressed (DE) genes for each dataset at fold-change (A/U or U/A) >1.3 and False Discovery Ratio (FDR) <0.05 (week 2: 41 genes; week 3: 618 genes and week 4: 39 genes). Functional analysis of DE genes using literature mining, BioDBnet and IPA revealed several biological processes and pathways associated with onset and progress of WBD. Top among them were dysregulation of energy metabolism, response to inflammation, vascular disease and remodeling of extracellular matrix. This study reveals that presence of molecular perturbations involving the vasculature, extracellular matrix and metabolism are pertinent to the onset and early pathogenesis of WBD in commercial meat-type chickens.

Functional significance of co-occurring mutations in PIK3CA and MAP3K1 in breast cancer

The PI3Kα signaling pathway is frequently hyper-activated in breast cancer (BrCa), as a result of mutations/amplifications in oncogenes (e.g. HER2), decreased function in tumor suppressors (e.g. PTEN) or activating mutations in key components of the pathway. In particular, activating mutations of PIK3CA (~45%) are frequently found in luminal A BrCa samples. Genomic studies have uncovered inactivating mutations in MAP3K1 (13-20%) and MAP2K4 (~8%), two upstream kinases of the JNK apoptotic pathway in luminal A BrCa samples. Further, simultaneous mutation of PIK3CA and MAP3K1 are found in ~11% of mutant PIK3CA tumors. How these two alterations may cooperate to elicit tumorigenesis and impact the sensitivity to PI3K and AKT inhibitors is currently unknown. Using CRISPR gene editing we have genetically disrupted MAP3K1 expression in mutant PIK3CA cell lines to specifically create in vitro models reflecting the mutational status of PIK3CA and MAP3K1 in BrCa patients. MAP3K1 deficient cell lines exhibited ~2.4-fold increased proliferation rate and decreased sensitivity to PI3Kα/δ(AZD8835) and AKT (AZD5363) inhibitors (~2.61 and ~5.23-fold IC₅₀ increases, respectively) compared with parental control cell lines. In addition, mechanistic analysis revealed that MAP3K1 disruption enhances AKT phosphorylation and downstream signaling and reduces sensitivity to AZD5363-mediated pathway inhibition. This appears to be a consequence of deficient MAP3K1-JNK signaling increasing IRS1 stability and therefore promoting IRS1 binding to p85, resulting in enhanced PI3Kα activity. Using 3D-MCF10A-PI3Kα^H1047R models, we found that MAP3K1 depletion increased overall acinar volume and counteracted AZD5363-mediated reduction of acinar growth due to enhanced proliferation and reduced apoptosis. Furthermore, in vivo efficacy studies revealed that MAP3K1-deficient MCF7 tumors were less sensitive to AKT inhibitor treatment, compared with parental MCF7 tumors. Our study provides mechanistic and in vivo evidence indicating a role for MAP3K1 as a tumor suppressor gene at least in the context of PIK3CA-mutant backgrounds. Further, our work predicts that MAP3K1 mutational status may be considered as a predictive biomarker for efficacy in PI3K pathway inhibitor trials.

MicroRNA profiles of BMSCs induced into osteoblasts with osteoinductive medium

MicroRNA (miRNA) plays an important role in cell differentiation and functions as a regulator. Therefore, miRNA is important in the process of bone marrow mesenchymal stem cells (BMSCs) being induced into osteoblasts. In this study, mouse BMSCs were induced with osteoinductive medium, the indices related to osteoblastic differentiation were assayed, including alkaline phosphatase, the deposit of calcium and protein levels of osteocalcin. Using miRNA microarray and reverse transcription-quantitative polymerase chain reaction analyses, differentially expressed miRNAs in the cells, which were induced with osteoinductive medium, were selected and identified. The target genes of the differentially expressed miRNAs were then predicted using bioinformatics analysis. The results revealed that osteoinductive medium promoted osteoblastic differentiation of BMSCs, and let-7c-5p, miR-181c-3p, miR-3092-3p and miR-5132-3p were identified as differentially expressed miRNAs in the cells treated with osteoinductive medium for 14 and 21 days. Certain target genes and signal pathways related to osteoblastic differentiation of the four miRNAs were predicted. These findings indicated the four differently expressed miRNAs may be potential regulators of osteoblastic differentiation, providing a basis for further study on the regulation of miRNAs in the osteogenic differentiation of BMSCs.

The MAPK hypothesis: immune-regulatory effects of MAPK-pathway genetic dysregulations and implications for breast cancer immunotherapy

With the advent of checkpoint inhibition, immunotherapy has revolutionized the clinical management of several cancers, but has demonstrated limited efficacy in mammary carcinoma. Transcriptomic profiling of cancer samples defined distinct immunophenotypic categories characterized by different prognostic and predictive connotations. In breast cancer, genomic alterations leading to the dysregulation of mitogen-activated protein kinase (MAPK) pathways have been linked to an immune-silent phenotype associated with poor outcome and treatment resistance. These aberrations include mutations of MAP3K1 and MAP2K4, amplification of KRAS, BRAF, and RAF1, and truncations of NF1. Anticancer therapies targeting MAPK signaling by BRAF and MEK inhibitors have demonstrated clear immunologic effects. These off-target properties could be exploited to convert the immune-silent tumor phenotype into an immune-active one. Preclinical evidence supports that MAPK-pathway inhibition can dramatically increase the efficacy of immunotherapy. In this review, we provide a detailed overview of the immunomodulatory impact of MAPK-pathway blockade through BRAF and MEK inhibitions. While BRAF inhibition might be relevant in melanoma only, MEK inhibition is potentially applicable to a wide range of tumors. Context-dependent similarities and differences of MAPK modulation will be dissected, in light of the complexity of the MAPK pathways. Therapeutic strategies combining the favorable effects of MAPK-oriented interventions on the tumor microenvironment while maintaining T-cell function will be presented. Finally, we will discuss recent studies highlighting the rationale for the implementation of MAPK-interference approaches in combination with checkpoint inhibitors and immune agonists in breast cancer.

Downregulation of PKCζ/Pard3/Pard6b is responsible for lung adenocarcinoma cell EMT and invasion

Atypical protein kinase C ζ (PKCζ) forms an apico-basal polarity complex with Partitioning Defective (Pard) 3 and Pard6 to regulate normal epithelial cell apico-basolateral polarization. The dissociation of the PKCζ/Pard3/Pard6 complex is essential for the disassembly of the tight/adherens junction and epithelial-mesenchymal transition (EMT) that is critical for tumor spreading. Loss of cell polarity and epithelial organization is strongly correlated with malignancy and tumor progression in some other cancer types. However, it is unclear whether the PKCζ/Pard3/Pard6 complex plays a role in the progression of non-small-cell lung cancer (NSCLC). We found that hypoxia downregulated the PKCζ/Pard3/Pard6 complex, correlating with induction of lung cancer cell migration and invasion. Silencing of the PKCζ/Pard3/Pard6 polarity complex components induced lung cancer cell EMT, invasion, and colonization in vivo. Suppression of Pard3 was associated with altered expression of genes regulating wound healing, cell apoptosis/death and cell motility, and particularly upregulation of MAP3K1 and fibronectin which are known to contribute to lung cancer progression. Human lung adenocarcinoma tissues expressed less Pard6b and PKCζ than the adjacent normal tissues and in experimental mouse lung adenocarcinoma, the levels of Pard3 and PKCζ were also decreased. In addition, we showed that a methylation locus in the gene body of Pard3 is positively associated with the expression of Pard3 and that methylation of the Pard3 gene increased cellular sensitivity to carboplatin, a common chemotherapy drug. Suppression of Pard3 increased chemoresistance in lung cancer cells. Together, these results suggest that reduced expression of PKCζ/Pard3/Pard6 contributes to NSCLC EMT, invasion, and chemoresistance.

JNK Signaling: Regulation and Functions Based on Complex Protein-Protein Partnerships

The c-Jun N-terminal kinases (JNKs), as members of the mitogen-activated protein kinase (MAPK) family, mediate eukaryotic cell responses to a wide range of abiotic and biotic stress insults. JNKs also regulate important physiological processes, including neuronal functions, immunological actions, and embryonic development, via their impact on gene expression, cytoskeletal protein dynamics, and cell death/survival pathways. Although the JNK pathway has been under study for >20 years, its complexity is still perplexing, with multiple protein partners of JNKs underlying the diversity of actions. Here we review the current knowledge of JNK structure and isoforms as well as the partnerships of JNKs with a range of intracellular proteins. Many of these proteins are direct substrates of the JNKs. We analyzed almost 100 of these target proteins in detail within a framework of their classification based on their regulation by JNKs. Examples of these JNK substrates include a diverse assortment of nuclear transcription factors (Jun, ATF2, Myc, Elk1), cytoplasmic proteins involved in cytoskeleton regulation (DCX, Tau, WDR62) or vesicular transport (JIP1, JIP3), cell membrane receptors (BMPR2), and mitochondrial proteins (Mcl1, Bim). In addition, because upstream signaling components impact JNK activity, we critically assessed the involvement of signaling scaffolds and the roles of feedback mechanisms in the JNK pathway. Despite a clarification of many regulatory events in JNK-dependent signaling during the past decade, many other structural and mechanistic insights are just beginning to be revealed. These advances open new opportunities to understand the role of JNK signaling in diverse physiological and pathophysiological states.

Genetic insights into Map3k-dependent proliferative expansion of T cells

Mapks are important regulators of T cell proliferative expansion and cell cycle progression. Detailed genetic analysis of unconventional iNKT cells in both Map3k1(ΔKD) and Lck(Cre/+)Map3k1(f/f) mice demonstrated that Mekk1 (encoded by Map3k1) signaling activates Mapks to regulate Cdkn1b (encoding p27(Kip1)) expression and p27(Kip1)-dependent proliferative expansion in response to antigen. Mekk1 signaling and activation of E3 ubiquitin ligase Itch, by a phosphorylation-dependent conformational change, is also an important regulatory mechanism for the control of T helper cell cytokine production. Cdkn1b expression is regulated by Mekk1-dependent signaling in differentiated Th17 cells. Mekk1 is one of the 19 Ste11-like Map3ks, and Mekk1 signaling regulates iNKT cell proliferative expansion in response to glycolipid antigens and T cell homeostasis in the liver. Tak1 (encoded by Map3k7), a related Map3k to Mekk1, similarly regulates the proliferative expansion and homeostasis of T cells in the liver, and this illustrates the importance of multiple Map3ks for mammalian Mapk signaling.

Identification of NR5A1 Mutations and Possible Digenic Inheritance in 46,XY Gonadal Dysgenesis

The phenotypic spectrum of patients carrying NR5A1 mutations ranges from 46,XY gonadal dysgenesis to male infertility. Phenotypic variability could be due to digenic or oligogenic inheritance of pathogenic variants in other testis-determining genes. Here, exome sequencing identified 2 pathogenic de novo NR5A1 mutations in 2 patients with 46,XY gonadal dysgenesis, p.Q206Tfs*20 and p.Arg313Cys. The latter patient also carried a missense mutation in MAP3K1. Our data extend the number of NR5A1 gene mutations associated with gonadal dysgenesis. The combination of an NR5A1 mutation with a MAP3K1 variant may explain the phenotypic variability associated with NR5A1 mutations.

T-Cell-Specific Deletion of Map3k1 Reveals the Critical Role for Mekk1 and Jnks in Cdkn1b-Dependent Proliferative Expansion

MAPK signaling is important for T lymphocyte development, homeostasis, and effector responses. To better understand the role of Mekk1 (encoded by Map3k1) in T cells, we conditionally deleted Map3k1 in Lck^Cre/+Map3k1^f/f mice, and these display larger iNKT cell populations within the liver, spleen, and bone marrow. Mekk1 signaling controls splenic and liver iNKT cell expansion in response to glycolipid antigen. Lck^Cre/+Map3k1^f/f mice have enhanced liver damage in response to glycolipid antigen. Mekk1 regulates Jnk activation in iNKT cells and binds and transfers Lys63-linked poly-ubiquitin onto Carma1. Map3k1 is critical for the regulation of p27^Kip1 (encoded by Cdkn1b).

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iNKT cell expansion is aberrant in Lck^Cre/+Map3k1^f/f mice

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Lck^Cre/+Map3k1^f/f mice have enhanced liver damage in response to glycolipids

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Mekk1 regulates TCR-dependent Jnk activation

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Mekk1 regulates p27^Kip1 expression to regulate proliferation