The involvement of FoxO in cell survival and chemosensitivity mediated by Mirk/Dyrk1B in ovarian cancer

Mirk/Dyrk1B controls ventral spinal cord development via Shh pathway

Cross-talk between Mirk/Dyrk1B kinase and Sonic hedgehog (Shh)/Gli pathway affects physiology and pathology. Here, we reveal a novel role for Dyrk1B in regulating ventral progenitor and neuron subtypes in the embryonic chick spinal cord (SC) via the Shh pathway. Using in ovo gain-and-loss-of-function approaches at E2, we report that Dyrk1B affects the proliferation and differentiation of neuronal progenitors at E4 and impacts on apoptosis specifically in the motor neuron (MN) domain. Especially, Dyrk1B overexpression decreases the numbers of ventral progenitors, MNs, and V2a interneurons, while the pharmacological inhibition of endogenous Dyrk1B kinase activity by AZ191 administration increases the numbers of ventral progenitors and MNs. Mechanistically, Dyrk1B overexpression suppresses Shh, Gli2 and Gli3 mRNA levels, while conversely, Shh, Gli2 and Gli3 transcription is increased in the presence of Dyrk1B inhibitor AZ191 or Smoothened agonist SAG. Most importantly, in phenotype rescue experiments, SAG restores the Dyrk1B-mediated dysregulation of ventral progenitors. Further at E6, Dyrk1B affects selectively the medial lateral motor neuron column (LMCm), consistent with the expression of Shh in this region. Collectively, these observations reveal a novel regulatory function of Dyrk1B kinase in suppressing the Shh/Gli pathway and thus affecting ventral subtypes in the developing spinal cord. These data render Dyrk1B a possible therapeutic target for motor neuron diseases.

Up-regulation of microRNA-183 reduces FOXO1 expression in gastric cancer patients with Helicobacter pylori infection

The aim of the study is to detect the expression of FOXO1 mRNA and protein in samples from gastric cancer patients with Helicobacter pylori (H. pylori) infection, and to investigate the relationship between FOXO1 expression and miR-183 expression. Twenty-six gastric cancer patients with H. pylori infection and 26 gastric cancer patients without H. pylori infection were included into experimental group and control group, respectively. Tumor tissues and peripheral blood were collected from all subjects. QRT-PCR was used to determine the expression of miRNA and mRNA. Western blotting was carried out to measure protein expression. Dual luciferase reporter assay was used to identify direct interaction between miRNA and 3'-UTR of mRNA. Cell proliferation was examined by CCK-8 assay. FOXO1 mRNA and protein expression was down-regulated in gastric cancer patients, being possibly related to H. pylori infection. The expression of miR-183 in tumor tissues and serum from gastric cancer patients with H. pylori infection was elevated, and probably regulated the expression of FOXO1 by direct targeting. Stimulation by H. pylori up-regulated the expression of miR-183 in gastric cancer AGS cells, and reduced the levels of FOXO1 mRNA and protein. Inhibition of miR-183 elevated the expression of FOXO1 and suppressed the proliferation of AGS cells. The present study demonstrates that the expression of FOXO1 in tumor tissues and blood from gastric cancer patients with H. pylori infection is significantly down-regulated, and may be related to the up-regulation of miR-183. H. pylori may regulate FOXO1 expression through miR-183 to affect the pathological process of gastric cancer.

Inhibition of DYRK1B suppresses inflammation in allergic contact dermatitis model and Th1/Th17 immune response

Allergic contact dermatitis (ACD) is a type IV hypersensitivity mainly mediated by Th1/Th17 immune response. Topical corticosteroid is currently the first-line treatment for allergic contact dermatitis (ACD) and systemic administration of immunosuppressive drugs are used in patients with severe disseminated cases. However, increased risk of adverse effects has limited their use. Thus, the development of a novel immunosuppressant for ACD with low toxicity is a challenging issue. In this study, we began our study by using a murine contact hypersensitivity (CHS) model of ACD to examine the immunosuppressive effects of DYRK1B inhibition. We found that mice treated with a selective DYRK1B inhibitor show reduced ear inflammation. In addition, a significant reduction of Th1 and Th17 cells in the regional lymph node upon DYRK1B inhibition was observed by FACS analysis. Studies in vitro further revealed that DYRK1B inhibitor does not only suppressed Th1 and Th17 differentiation, but also promotes regulatory T cells (Treg) differentiation. Mechanistically, FOXO1 signaling was enhanced due to the suppression of FOXO1Ser329 phosphorylation in the presence of DYRK1B inhibitor. Therefore, these findings suggest that DYRK1B regulates CD4 T cell differentiation through FOXO1 phosphorylation and DYRK1B inhibitor has a potential as a novel agent for treatment of ACD.

A novel defined risk signature of endoplasmic reticulum stress-related genes for predicting the prognosis and immune infiltration status of ovarian cancer

Endoplasmic reticulum (ER) stress, as an emerging hallmark feature of cancer, has a considerable impact on cell proliferation, metastasis, invasion, and chemotherapy resistance. Ovarian cancer (OvCa) is one of the leading causes of cancer-related mortality across the world due to the late stage of disease at diagnosis. Studies have explored the influence of ER stress on OvCa in recent years, while the predictive role of ER stress-related genes in OvCa prognosis remains unexplored. Here, we enrolled 552 cases of ER stress-related genes involved in OvCa from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cohorts for the screening of prognosis-related genes. The least absolute shrinkage and selection operator (LASSO) regression was applied to establish an ER stress-related risk signature based on the TCGA cohort. A seven-gene signature revealed a favorable predictive efficacy for the TCGA, International Cancer Genome Consortium (ICGC), and another GEO cohort (P<0.001, P<0.001, and P=0.04, respectively). Moreover, functional annotation indicated that this signature was enriched in cellular response and senescence, cytokines interaction, as well as multiple immune-associated terms. The immune infiltration profiles further delineated an immunologic unresponsive status in the high-risk group. In conclusion, ER stress-related genes are vital factors predicting the prognosis of OvCa, and possess great application potential in the clinic.

FoxO3 might be involved in the inflammatory response of human monocytes to lipopolysaccharide through regulating expression of toll like receptor 4

OBJECTIVE

Previous studies have found that forkhead box o3 S574 phosphorylation status can regulate inflammation by inducing monocytes/macrophages apoptosis, and whether it directly affects the inflammatory response of monocytes has not been demonstrated. The aim of this study was to investigate the role of forkhead box o3 in inflammatory response of monocytes against lipopolysaccharide.

METHODS

THP-1 cells were used to knock down or overexpress forkhead box o3 and its mutants, and then detect the activation of inflammatory cytokines expression and activation of nuclear factor kappa B after lipopolysaccharide treatment.

RESULTS

The present study demonstrated that lipopolysaccharide can up-regulate forkhead box o3 protein expression, especially the non-phosphorylated form at S574, in a post-transcriptional way. Knockdown of forkhead box o3 attenuated lipopolysaccharide mediated nuclear factor kappa B activation and downstream inflammatory cytokines expression. When overexpressing forkhead box o3, only non-phosphorylated S574A forkhead box o3 mutant enhanced lipopolysaccharide induced nuclear factor kappa B activation and inflammatory cytokines expression. Further studies have found that S574A forkhead box o3 may promote toll like receptor 4 expression through binding and accelerating its transcriptional activity from promoter.

CONCLUSION

There might be a positive feedback loop between lipopolysaccharide and forkhead box o3 in monocytes to promote the lipopolysaccharide mediated inflammatory response.

A Bioinformatics Evaluation of the Role of Dual-Specificity Tyrosine-Regulated Kinases in Colorectal Cancer

Simple Summary

The dual-specificity tyrosine-regulated kinase (DYRK) family has been implicated in various diseases, including cancer. However, its role in colorectal cancer has not been elucidated. In this research, we used publicly available web-based tools to investigate DYRKs status in colorectal cancer. Our results showed that among DYRKs, only DYRK1A was upregulated significantly in late tumor stages, and it is associated with poor prognosis for colorectal cancer patients. These finding comprehensively characterized DYRK1A as a potential new therapeutic approach in CRC, especially in late tumor stages.

Abstract

Colorectal cancer (CRC) is the third most common cancer worldwide and has an increasing incidence in younger populations. The dual-specificity tyrosine-regulated kinase (DYRK) family has been implicated in various diseases, including cancer. However, the role and contribution of the distinct family members in regulating CRC tumorigenesis has not been addressed yet. Herein, we used publicly available CRC patient datasets (TCGA RNA sequence) and several bioinformatics webtools to perform in silico analysis (GTEx, GENT2, GEPIA2, cBioPortal, GSCALite, TIMER2, and UALCAN). We aimed to investigate the DYRK family member expression pattern, prognostic value, and oncological roles in CRC. This study shed light on the role of distinct DYRK family members in CRC and their potential outcome predictive value. Based on mRNA level, DYRK1A is upregulated in late tumor stages, with lymph node and distant metastasis. All DYRKs were found to be implicated in cancer-associated pathways, indicating their key role in CRC pathogenesis. No significant DYRK mutations were identified, suggesting that DYRK expression variation in normal vs. tumor samples is likely linked to epigenetic regulation. The expression of DYRK1A and DYRK3 expression correlated with immune-infiltrating cells in the tumor microenvironment and was upregulated in MSI subtypes, pointing to their potential role as biomarkers for immunotherapy. This comprehensive bioinformatics analysis will set directions for future biological studies to further exploit the molecular basis of these findings and explore the potential of DYRK1A modulation as a novel targeted therapy for CRC.

Targeting DYRK1A/B kinases to modulate p21-cyclin D1-p27 signalling and induce anti-tumour activity in a model of human glioblastoma

The dual-specificity tyrosine-regulated kinases DYRK1A and DYRK1B play a key role in controlling the quiescence-proliferation switch in cancer cells. Serum reduction of U87MG 2D cultures or multi-cellular tumour spheroids induced a quiescent like state characterized by increased DYRK1B and p27, and decreased pRb and cyclin D1. VER-239353 is a potent, selective inhibitor of the DYRK1A and DYRK1B kinases identified through fragment and structure-guided drug discovery. Inhibition of DYRK1A/B by VER-239353 in quiescent U87MG cells increased pRb, DYRK1B and cyclin D1 but also increased the cell cycle inhibitors p21 and p27. This resulted in exit from G0 but subsequent arrest in G1. DYRK1A/B inhibition reduced the proliferation of U87MG cells in 2D and 3D culture with greater effects observed under reduced serum conditions. Paradoxically, the induced re-expression of cell cycle proteins by DYRK1A/B inhibition further inhibited cell proliferation. Cell growth arrest induced in quiescent cells by DYRK1A/B inhibition was reversible through the addition of growth-promoting factors. DYRK inhibition-induced DNA damage and synergized with a CHK1 inhibitor in the U87MG spheroids. In vivo, DYRK1A/B inhibition-induced tumour stasis in a U87MG tumour xenograft model. These results suggest that further evaluation of VER-239353 as a treatment for glioblastoma is therefore warranted.

Forkhead box O1 targeting replication factor C subunit 2 expression promotes glioma temozolomide resistance and survival

Background

Additional mechanisms of temozolomide (TMZ) resistance in gliomas remain uncertain. The aim of this study was to identify another DNA repair mechanism involving forkhead box O1 (FoxO1) and replicator C2 (RFC2) in gliomas.

Methods

We established glioma cells against TMZ, U87R, by exposure to TMZ. Proliferation rate Cell counting kit-8 (CCK8) was used, and epithelial-mesenchymal transition (EMT)-related markers were detected by western blot. The association between FoxO1 and RFC2 was analyzed by heat maps and scatter plot, and Real-time reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were used to detect the effect of FoxO1 on the expression of RFC2. The regulation effect of FoxO1 on RFC2 expression was analyzed by luciferase reporter gene assay. Knockdown of FoxO1/RFC2 was achieved via short hairpin RNA (shRNA), the effect of knockdown on the proliferation was determined by CCK8 assay and colony formation assay, and apoptosis was examined by flow cytometry and immunoblotting.

Results

The TMZ-resistant glioma cell line, U87R, was established. The FoxO1 and RFC2 proteins increased significantly in U87R. The expression of FoxO1 and RFC2 were positively related in glioma tissues. We found that FoxO1 contributes to TMZ resistance and cell survival via regulating the expression of RFC2. Moreover, FoxO1 functions as a transcriptional activator to RFC2 by binding to the promoter of RFC2. Furthermore, knockdown of FoxO1/RFC2 suppressed cell proliferation, TMZ resistance, and induced apoptosis in U87R.

Conclusions

The FoxO1/RFC2 signaling pathway promotes glioma cell proliferation and TMZ resistance, suggesting that the FoxO1/RFC2 pathway may be a potential target for TMZ-resistant glioma therapy.

Dual Specificity Kinase DYRK3 Promotes Aggressiveness of Glioblastoma by Altering Mitochondrial Morphology and Function

Glioblastoma multiforme (GBM) is a malignant primary brain tumor with poor patient prognosis. Although the standard treatment of GBM is surgery followed by chemotherapy and radiotherapy, often a small portion of surviving tumor cells acquire therapeutic resistance and become more aggressive. Recently, altered kinase expression and activity have been shown to determine metabolic flux in tumor cells and metabolic reprogramming has emerged as a tumor progression regulatory mechanism. Here we investigated novel kinase-mediated metabolic alterations that lead to acquired GBM radioresistance and malignancy. We utilized transcriptomic analyses within a radioresistant GBM orthotopic xenograft mouse model that overexpresses the dual specificity tyrosine-phosphorylation-regulated kinase 3 (DYRK3). We find that within GBM cells, radiation exposure induces DYRK3 expression and DYRK3 regulates mammalian target of rapamycin complex 1 (mTORC1) activity through phosphorylation of proline-rich AKT1 substrate 1 (PRAS40). We also find that DYRK3 knockdown inhibits dynamin-related protein 1 (DRP1)-mediated mitochondrial fission, leading to increased oxidative phosphorylation (OXPHOS) and reduced glycolysis. Importantly, enforced DYRK3 downregulation following irradiation significantly impaired GBM cell migration and invasion. Collectively, we suggest DYRK3 suppression may be a novel strategy for preventing GBM malignancy through regulating mitochondrial metabolism.

Minibrain-related kinase/dual-specificity tyrosine-regulated kinase 1B implication in stem/cancer stem cells biology

Dual-specificity tyrosine phosphorylation-regulated kinase 1B (DYRK1B), also known as minibrain-related kinase (MIRK) is one of the best functionally studied members of the DYRK kinase family. DYRKs comprise a family of protein kinases that are emerging modulators of signal transduction pathways, cell proliferation and differentiation, survival, and cell motility. DYRKs were found to participate in several signaling pathways critical for development and cell homeostasis. In this review, we focus on the DYRK1B protein kinase from a functional point of view concerning the signaling pathways through which DYRK1B exerts its cell type-dependent function in a positive or negative manner, in development and human diseases. In particular, we focus on the physiological role of DYRK1B in behavior of stem cells in myogenesis, adipogenesis, spermatogenesis and neurogenesis, as well as in its pathological implication in cancer and metabolic syndrome. Thus, understanding of the molecular mechanisms that regulate signaling pathways is of high importance. Recent studies have identified a close regulatory connection between DYRK1B and the hedgehog (HH) signaling pathway. Here, we aim to bring together what is known about the functional integration and cross-talk between DYRK1B and several signaling pathways, such as HH, RAS and PI3K/mTOR/AKT, as well as how this might affect cellular and molecular processes in development, physiology, and pathology. Thus, this review summarizes the major known functions of DYRK1B kinase, as well as the mechanisms by which DYRK1B exerts its functions in development and human diseases focusing on the homeostasis of stem and cancer stem cells.

FUT4siRNA augments the chemosensitivity of non-small cell lung cancer to cisplatin through activation of FOXO1-induced apoptosis

Background

Increased fucosylation is associated with the chemoresistance phenotype. Meanwhile, fucosyltransferase IV (FUT4) amounts are frequently elevated in lung cancer and may be related to increased chemoresistance.

Methods

In the present work, FUT4’s role in cisplatin-induced apoptosis was assessed in A549 and H1975 cells, respectively. To clarify whether the FUT4 gene attenuates chemosensitivity in tumor cells, we constructed FUT4siRNA and evaluated its effects on cisplatin-induced apoptosis and cell growth inhibition. Cell viability, apoptosis, migration and invasion assay were conducted to investigate cisplatin sensitivity. The activation of EGFR/AKT/FOXO1 signaling were measured by western blot. The translocation of FOXO1 was assessed by IFC using Laser Scanning Confocal Microscope.

Results

We found that FUT4 knockdown dose-dependently increased cisplatin-associated cytotoxicity. Furthermore, FUT4 silencing induced apoptosis and inhibited proliferation in A549 and H1975 cells by suppressing Akt and FOXO1 phosphorylation induced by cisplatin administration, which resulted in nuclear translocation of FOXO1.

Conclusion

These results suggested FUT4 might control chemoresistance to cisplatin in lung cancer by suppressing FOXO1-induced apoptosis.

CD83, a Novel MAPK Signaling Pathway Interactor, Determines Ovarian Cancer Cell Fate

Ovarian cancer is a leading cause of death from gynecologic malignancies worldwide. Although CD83 is widely described as a solid marker for mature dendritic cells, emerging pieces of evidence indicate the expression of membrane protein CD83 by various tumor cells, including ovarian cancer cells. However, the potential role of CD83 in ovarian cancer cell properties and development remains absolutely unknown. By using human CD83 stable overexpression and knockdown sublines of several ovarian cancer cells, we observed that CD83 advanced the growth proliferation, colony formation ability, spheroid formation, and in vivo tumorigenicity of ovarian cancer cells; surprisingly, CD83 limited their migration and invasion potentials. Positive regulation of proliferation/stemness factors (e.g., cyclin-CDKs and KIT/CD44) but negative regulation of matrix metallopeptidases (e.g., MMP1 and 7) by CD83 were revealed by the integrated analysis of transcriptome and proteome. Furthermore, immunoprecipitation-mass spectrometry (IP-MS) and co-immunoprecipitation (Co-IP) first identified the association of CD83 with MAP3K7 (also known as TAK1) and MAP3K7-binding protein TAB1 on the cell membrane. Moreover, CD83 functions through the activation of MAP3K7-MEK1/2-ERK1/2 cascades to further regulate downstream FOXO1/p21/CDK2/CCNB1 and STAT3/DKK1 signaling pathways, thus activating proliferation and spheroid formation of ovarian cancer cells, respectively. Collectively, our findings define a CD83-MAPK pathway in the regulation of proliferation and stemness in ovarian cancer cells, with potential therapeutic applications in blocking their progression.

The DYRK Family of Kinases in Cancer: Molecular Functions and Therapeutic Opportunities

DYRK (dual-specificity tyrosine-regulated kinases) are an evolutionary conserved family of protein kinases with members from yeast to humans. In humans, DYRKs are pleiotropic factors that phosphorylate a broad set of proteins involved in many different cellular processes. These include factors that have been associated with all the hallmarks of cancer, from genomic instability to increased proliferation and resistance, programmed cell death, or signaling pathways whose dysfunction is relevant to tumor onset and progression. In accordance with an involvement of DYRK kinases in the regulation of tumorigenic processes, an increasing number of research studies have been published in recent years showing either alterations of DYRK gene expression in tumor samples and/or providing evidence of DYRK-dependent mechanisms that contribute to tumor initiation and/or progression. In the present article, we will review the current understanding of the role of DYRK family members in cancer initiation and progression, providing an overview of the small molecules that act as DYRK inhibitors and discussing the clinical implications and therapeutic opportunities currently available.

Polymerase independent repression of FoxO1 transcription by sequence-specific PARP1 binding to FoxO1 promoter

Poly(ADP-ribose) polymerase 1 (PARP1) regulates gene transcription in addition to functioning as a DNA repair factor. Forkhead box O1 (FoxO1) is a transcription factor involved in extensive biological processes. Here, we report that PARP1 binds to two separate motifs on the FoxO1 promoter and represses its transcription in a polymerase-independent manner. Using PARP1-knock out (KO) cells, wild-type-PARP1-complemented cells and catalytic mutant PARP1^E988K-reconstituted cells, we investigated transcriptional regulation by PARP1. PARP1 loss led to reduced DNA damage response and ~362-fold resistance to five PARP inhibitors (PARPis) in Ewing sarcoma cells. RNA sequencing showed 492 differentially expressed genes in a PARP1-KO subline, in which the FoxO1 mRNA levels increased up to more than five times. The change in the FoxO1 expression was confirmed at both mRNA and protein levels in different PARP1-KO and complemented cells. Moreover, exogenous PARP1 overexpression reduced the endogenous FoxO1 protein in RD-ES cells. Competitive EMSA and ChIP assays revealed that PARP1 specifically bound to the FoxO1 promoter. DNase I footprinting, mutation analyses, and DNA pulldown FREP assays showed that PARP1 bound to two particular nucleotide sequences separately located at −813 to −826 bp and −1805 to −1828 bp regions on the FoxO1 promoter. Either the PARPi olaparib or the PARP1 catalytic mutation (E988K) did not impair the repression of PARP1 on the FoxO1 expression. Exogenous FoxO1 overexpression did not impair cellular PARPi sensitivity. These findings demonstrate a new PARP1-gene promoter binding mode and a new transcriptional FoxO1 gene repressor.

How to design potent and selective DYRK1B inhibitors? Molecular modeling study

DYRK1B protein kinase is an emerging anticancer target due to its overexpression in a variety of cancers and its role in cancer chemoresistance through maintaining cancer cells in the G0 (quiescent) state. Consequently, there is a growing interest in the development of potent and selective DYRK1B inhibitors for anticancer therapy. One of the major off-targets is another protein kinase, GSK3β, which phosphorylates an important regulator of cell cycle progression on the same residue as DYRK1B and is involved in multiple signaling pathways. In the current work, we performed a detailed comparative structural analysis of DYRK1B and GSK3β ATP-binding sites and identified key regions responsible for selectivity. As the crystal structure of DYRK1B has never been reported, we built and optimized a homology model by comparative modeling and metadynamics simulations. Calculation of interaction energies between docked ligands in the ATP-binding sites of both kinases allowed us to pinpoint key residues responsible for potency and selectivity. Specifically, the role of the gatekeeper residues in DYRK1B and GSK3β is discussed in detail, and two other residues are identified as key to selectivity of DYRK1B inhibition versus GSK3β. The analysis presented in this work was used to support the design of potent and selective azaindole-quinoline-based DYRK1B inhibitors and can facilitate development of more selective inhibitors for DYRK kinases.

Phosphorylation and acetylation modifications of FOXO3a: Independently or synergistically?

Forkhead box class O 3a (FOXO3a) is a transcription factor that has emerged as being a tumor suppressor and longevity factor. The precise regulation of FOXO3a transactivation of target genes is achieved via post-translational modifications (PTMs) and specific protein-protein interactions. The multiple types of PTMs that FOXO3a undergoes, including phosphorylation, acetylation, methylation and ubiquitination, serve important roles in directing its subcellular localization and transcription activity, which are central to the integration of insulin/growth factor signaling and oxidative/nutrient stress signaling. The present review summarizes the modifications of FOXO3a that occur via phosphorylation and acetylation. In addition, the synergistic effect of multiple phosphorylations on FOXO3a and the crosstalk between phosphorylation and acetylation in the regulation of FOXO3a are discussed. These discussions may highlight potential strategies for the prevention of cancer and aging.

A dual specificity kinase, DYRK1A, as a potential therapeutic target for head and neck squamous cell carcinoma

Despite advances in clinical management, 5-year survival rate in patients with late-stage head and neck squamous cell carcinoma (HNSCC) has not improved significantly over the past decade. Targeted therapies have emerged as one of the most promising approaches to treat several malignancies. Though tyrosine phosphorylation accounts for a minority of total phosphorylation, it is critical for activation of signaling pathways and plays a significant role in driving cancers. To identify activated tyrosine kinase signaling pathways in HNSCC, we compared the phosphotyrosine profiles of a panel of HNSCC cell lines to a normal oral keratinocyte cell line. Dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A (DYRK1A) was one of the kinases hyperphosphorylated at Tyr-321 in all HNSCC cell lines. Inhibition of DYRK1A resulted in an increased apoptosis and decrease in invasion and colony formation ability of HNSCC cell lines. Further, administration of the small molecular inhibitor against DYRK1A in mice bearing HNSCC xenograft tumors induced regression of tumor growth. Immunohistochemical labeling of DYRK1A in primary tumor tissues using tissue microarrays revealed strong to moderate staining of DYRK1A in 97.5% (39/40) of HNSCC tissues analyzed. Taken together our results suggest that DYRK1A could be a novel therapeutic target in HNSCC.

Role of dual specificity tyrosine-phosphorylation-regulated kinase 1B (Dyrk1B) in S-phase entry of HPV E7 expressing cells from quiescence

The high-risk human papillomavirus (HPV) is the causative agent for cervical cancer. The HPV E7 oncogene promotes S-phase entry from quiescent state in the presence of elevated cell cycle inhibitor p27Kip1, a function that may contribute to carcinogenesis. However, the mechanism by which HPV E7 induces quiescent cells to entry into S-phase is not fully understood. Interestingly, we found that Dyrk1B, a dual-specificity kinase and negative regulator of cell proliferation in quiescent cells, was upregulated in E7 expressing cells. Surprisingly and in contrast to what was previously reported, Dyrk1B played a positive role in S-phase entry of quiescent HPV E7 expressing cells. Mechanistically, Dyrk1B contributed to p27 phosphorylation (at serine 10 and threonine 198), which was important for the proliferation of HPV E7 expressing cells. Moreover, Dyrk1B up-regulated HPV E7. Taken together, our studies uncovered a novel function of Dyrk1B in high-risk HPV E7-mediated cell proliferation. Dyrk1B may serve as a target for therapy in HPV-associated cancers.

The forkhead transcription factor FOXO1 mediates cisplatin resistance in gastric cancer cells by activating phosphoinositide 3-kinase/Akt pathway

BACKGROUND

Cisplatin (CDDP) is one of the most important chemotherapeutic agents in the treatment of advanced gastric cancer, but its efficacy is limited by CDDP resistance. Because the transcription factor FOXO1 is related to chemoresistance in various cancer cells, we investigated the function of FOXO1 in CDDP resistance in human gastric cancer cells.

METHODS

Human gastric cancer cell lines MKN45 and SNU-601 were used. FOXO1 activation was modulated by transfection of FOXO1 AAA mutant gene or FOXO1 shRNA. The effects of FOXO1 on cell growth and CDDP cytotoxicity were assessed by crystal violet assay. Protein expressions of FOXO1, p110α, pAkt, and Akt were analyzed by Western blotting, and FOXO1 mRNA expression was evaluated by semiquantitative reverse transcription-polymerase chain reaction. FOXO1 activity was determined by luciferase reporter assay, and cell apoptosis was assessed by DAPI staining and Western blotting for PARP cleavage.

RESULTS

Cisplatin treatment induced FOXO1 expression and activation in both gastric cancer cell lines. FOXO1 overexpression increased the CDDP resistance without changes in cell growth, whereas FOXO1 silencing enhanced CDDP cytotoxicity along with apoptotic characteristics. Both constitutive and CDDP-induced FOXO1 activations were accompanied by an increase in p110α and pAkt expression. Furthermore, Akt inhibition by LY294002 treatment restored the CDDP cytotoxicity that was suppressed by FOXO1 overexpression.

CONCLUSION

FOXO1 inhibits CDDP-induced apoptosis in gastric cancer cells via activating PI3K/Akt pathway. Thus, FOXO1 may be an useful pharmacological indicator to predict CDDP efficacy in gastric cancer treatment.

Investigating the utility of clinical outcome-guided mutual information network in network-based Cox regression

BACKGROUND

Network-based approaches have recently gained considerable popularity in high- dimensional regression settings. For example, the Cox regression model is widely used in expression analysis to predict the survival of patients. However, as the number of genes becomes substantially larger than the number of samples, the traditional Cox or L2-regularized Cox models are still prone to noise and produce unreliable estimations of regression coefficients. A recent approach called the network-based Cox (Net-Cox) model attempts to resolve this issue by incorporating prior gene network information into the Cox regression. The Net-Cox model has shown to outperform the models that do not use this network information.

RESULTS

In this study, we demonstrate an alternative network construction method for the outcome-guided gene interaction network, and we investigate its utility in survival analysis using Net-Cox regression as compared with conventional networks, such as co-expression or static networks obtained from the existing knowledgebase. Our network edges consist of gene pairs that are significantly associated with the clinical outcome. We measure the strength of this association using mutual information between the gene pair and the clinical outcome. We applied this approach to ovarian cancer patients' data in The Cancer Genome Atlas (TCGA) and compared the predictive performance of the proposed approach with those that use other types of networks.

CONCLUSIONS

We found that the alternative outcome-guided mutual information network further improved the prediction power of the network-based Cox regression. We expect that a modification of the network regularization term in the Net-Cox model could further improve its prediction power because the properties of our network edges are not optimally reflected in its current form.

Mirk/dyrk1B kinase is upregulated following inhibition of mTOR

The PI3K/PTEN/Akt/mTOR/p70S6K pathway is one of the most frequently deregulated signaling pathways in solid tumors and has a functional role in drug resistance. However, targeting this pathway leads to compensatory activation of several mediators of cell survival. Expression of the reactive oxygen species-controlling kinase Mirk/dyrk1B was increased severalfold by the mammalian target of rapamycin (mTOR) inhibitors RAD001, WYE354 and rapamycin, with less effect by the Akt inhibitors AZD5363 and MK-2206. Upregulation of Mirk messenger RNA (mRNA) expression was mediated by cyclic AMP response element binding protein (CREB) binding to two sites in the Mirk promoter upstream of the transcription start site and one site within exon 4. Depletion of CREB reduced Mirk expression, whereas depletion of mTOR increased it. Moreover, hydroxytamoxifen activation of an Akt-estrogen receptor construct blocked an increase in Mirk mRNA and protein. Addition of a Mirk/dyrk1B kinase inhibitor increased the sensitivity of Panc1 pancreatic cancer cells and three different ovarian cancer cell lines to the mTOR inhibitor RAD001. Targeting Mirk kinase could improve the utility of mTOR inhibitors and so presents an attractive drug target.

FoxO3a and disease progression

The Forkhead box O (FoxO) family has recently been highlighted as an important transcriptional regulator of crucial proteins associated with the many diverse functions of cells. So far, FoxO1, FoxO3a, FoxO4 and FoxO6 proteins have been identified in humans. Although each FoxO family member has its own role, unlike the other FoxO families, FoxO3a has been extensively studied because of its rather unique and pivotal regulation of cell proliferation, apoptosis, metabolism, stress management and longevity. FoxO3a alteration is closely linked to the progression of several types of cancers, fibrosis and other types of diseases. In this review, we will examine the function of FoxO3a in disease progression and also explore FoxO3a’s regulatory mechanisms. We will also discuss FoxO3a as a potential target for the treatment of several types of disease.

Mirk kinase inhibition targets ovarian cancer ascites

The Mirk/dyrk1B gene is commonly amplified or upregulated in ovarian cancers, and Mirk is an active kinase in these cancers. Mirk mediates cancer cell survival by decreasing toxic ROS levels through maintaining expression of a series of antioxidant genes, possibly through its transcriptional activator functions. Mirk has the unusual property of being most active in quiescent cancer cells because of marked transcriptional downregulation by Akt/mTOR signaling and by MEK/erk signaling in cycling cells. Metastatic ovarian cancer cells form ascites, non-adherent multicellular aggregates floating within the peritoneal fluid. Most ascites cancer cells are in a reversible quiescent, dormant state, suggesting that Mirk might be expressed in these quiescent cells and thus a therapeutic target. The current studies show that ovarian cancer cell line spheroids that mimic ascites cancer spheroids were largely quiescent in G0/G1, and enriched in Mirk and the quiescence proteins, p130/Rb2 and the CDKI p27. Mirk kinase inhibition in spheroids made from established cell lines and in patient-derived ascites cancer cell spheroids reduced spheroid volume, disrupted spheroid structure to single cells, increased apoptosis, and decreased cell numbers. Earlier studies had shown that the mTOR inhibitor RAD001 increased transcription of the Mirk/dyrk1B gene, so treatments combined RAD001 with the most active Mirk kinase inhibitor. The number of ascites cells from 9 patients was reduced a similar amount by cisplatin, Mirk kinase inhibition or RAD001, but reduced substantially more, about 90%, by concurrent treatment with both the Mirk kinase inhibitor EHT5372 and RAD001. Addition of RAD001 increased the amount of toxic ROS induced by Mirk kinase inhibition. Two ascites samples taken one month apart gave similar drug responses, showing reproducibility of the techniques. Thus Mirk/dyrk1B kinase may be a therapeutic target in ovarian cancer ascites.

Design and synthesis of a library of lead-like 2,4-bisheterocyclic substituted thiophenes as selective Dyrk/Clk inhibitors

The Dyrk family of protein kinases is implicated in the pathogenesis of several diseases, including cancer and neurodegeneration. Pharmacological inhibitors were mainly described for Dyrk1A so far, but in fewer cases for Dyrk1B, Dyrk2 or other isoforms. Herein, we report the development and optimization of 2,4-bisheterocyclic substituted thiophenes as a novel class of Dyrk inhibitors. The optimized hit compounds displayed favorable pharmacokinetic properties and high ligand efficiencies, and inhibited Dyrk1B in intact cells. In a larger selectivity screen, only Clk1 and Clk4 were identified as additional targets of compound 48, but no other kinases frequently reported as off-targets. Interestingly, Dyrk1A is implicated in the regulation of alternative splicing, a function shared with Clk1/Clk4; thus, some of the dual inhibitors might be useful as efficient splicing modulators. A further compound (29) inhibited Dyrk1A and 1B with an IC50 of 130 nM, showing a moderate selectivity over Dyrk2. Since penetration of the central nervous system (CNS) seems possible based on the physicochemical properties, this compound might serve as a lead for the development of potential therapeutic agents against glioblastoma. Furthermore, an inhibitor selective for Dyrk2 (24) was also identified, which might be are suitable as a pharmacological tool to dissect Dyrk2 isoform-mediated functions.

miR-153 supports colorectal cancer progression via pleiotropic effects that enhance invasion and chemotherapeutic resistance

Although microRNAs (miRNA) have been broadly studied in cancer, comparatively less is understood about their role in progression. Here we report that miR-153 has a dual role during progression of colorectal cancer by enhancing cellular invasiveness and platinum-based chemotherapy resistance. miRNA profiling revealed that miR-153 was highly expressed in a cellular model of advanced stage colorectal cancer. Its upregulation was also noted in primary human colorectal cancer compared with normal colonic epithelium and in more advanced colorectal cancer stages compared with early stage disease. In colorectal cancer patients followed for 50 months, 21 of 30 patients with high levels of miR-153 had disease progression compared with others in this group with low levels of miR-153. Functional studies revealed that miR-153 upregulation increased colorectal cancer invasiveness and resistance to oxaliplatin and cisplatin both in vitro and in vivo. Mechanistic investigations indicated that miR-153 promoted invasiveness indirectly by inducing matrix metalloprotease enzyme 9 production, whereas drug resistance was mediated directly by inhibiting the Forkhead transcription factor Forkhead box O3a (FOXO3a). In support of the latter finding, we found that levels of miR-153 and FOXO3a were inversely correlated in matched human colorectal cancer specimens. Our findings establish key roles for miR-153 overexpression in colorectal cancer progression, rationalizing therapeutic strategies to target expression of this miRNA for colorectal cancer treatment.

Mirk/dyrk1B Kinase in Ovarian Cancer

Mirk/dyrk1B kinase is expressed in about 75% of resected human ovarian cancers and in most ovarian cancer cell lines with amplification in the OVCAR3 line. Mirk (minibrain-related kinase) is a member of the Minibrain/dyrk family of related serine/threonine kinases. Mirk maintains cells in a quiescent state by stabilizing the CDK inhibitor p27 and by inducing the breakdown of cyclin D isoforms. Mirk also stabilizes the DREAM complex, which maintains G0 quiescence by sequestering transcription factors needed to enter cycle. By entering a quiescent state, tumor cells can resist the nutrient deficiencies, hypoxic and acidic conditions within the tumor mass. Mirk maintains the viability of quiescent ovarian cancer cells by reducing intracellular levels of reactive oxygen species. CDKN2A-negative ovarian cancer cells treated with a Mirk kinase inhibitor escaped G0/G1 quiescence, entered cycle with high ROS levels and underwent apoptosis. The ROS scavenger N-acetyl cysteine reduced the extent of cancer cell loss. In contrast, the Mirk kinase inhibitor slightly reduced the fraction of G0 quiescent diploid epithelial cells and fibroblasts, and the majority of the cells pushed into cycle accumulated in G2 + M. Apoptotic sub-G0/G1 cells were not detected. Thus, normal cells were spared because of their expression of CDK inhibitors that blocked unregulated cycling and Mirk kinase inhibitor-treated normal diploid cells were about as viable as untreated controls.

Mirk/Dyrk1B mediates G0/G1 to S phase cell cycle progression and cell survival involving MAPK/ERK signaling in human cancer cells

Background

Mirk/Dyrk1B contributes to G0 arrest by destabilization of cyclin D1 and stabilization of p27kip1 to maintain the viability of quiescent human cancer cells, and it could be negatively regulated by mitogenic-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling. This study was performed to investigate the effect of Mirk/Dyrk1B on cell cycle and survival of human cancer cells involving MAPK/ERK signaling.

Methods

The correlations between Mirk/Dyrk1B expression and active ERK1/2 detected by western blot in both ovarian cancer and non-small cell lung cancer (NSCLC) cells were analyzed by simple regression. Mirk/Dyrk1B unique phosphopeptides with sites associated with Mirk/Dyrk1B protein were isolated and quantitated by liquid chromatography coupled to tandem mass/mass spectrometry (LC-MS/MS) proteomics analysis. The human cancer cells were treated with small interfering RNAs (siRNAs) and/or U0126, an inhibitor of MEK for indicated duration, followed by investigating the alterations of cell cycle and apoptosis as well as related proteins examined by flow cytometry and Western blot, respectively.

Results

Our study demonstrated the widely expressed Mirk/Dyrk1B proteins in the human cancer cells were positively correlated with the levels of activated ERK1/2. Moreover, Mirk/Dyrk1B protein expressions consistent with the tyrosine autophosphorylated levels in the human cancer cells were increased by U0126 or growth factor-depleted culture. Conversely, knockdown of Mirk/Dyrk1B by siRNA led to up-regulated activation of c-Raf-MEK-ERK1/2 pathway and subsequent changes in cell cycle proteins (cyclin D1, p27kip1), accompanied by increased growth rate and cells from G0/G1 into S of cell cycle which could be blocked by U0126 in a dose-dependent manner, indicating Mirk/Dyrk1B may sequester MAPK/ERK pathway, and vice versa. Whereas, combined Mirk siRNA and U0126 induced cell apoptosis in the human cancer cells.

Conclusions

These data together show that Mirk/Dyrk1B mediates cell cycle and survival via interacting with MAPK/ERK signals and simultaneous inhibition of both pathways may be a novel therapeutic target for human cancer.

An aqueous extract of Fagonia cretica induces DNA damage, cell cycle arrest and apoptosis in breast cancer cells via FOXO3a and p53 expression

BACKGROUND

Plants have proved to be an important source of anti-cancer drugs. Here we have investigated the cytotoxic action of an aqueous extract of Fagonia cretica, used widely as a herbal tea-based treatment for breast cancer.

METHODOLOGY/PRINCIPAL FINDINGS

Using flow cytometric analysis of cells labeled with cyclin A, annexin V and propidium iodide, we describe a time and dose-dependent arrest of the cell cycle in G0/G1 phase of the cell cycle and apoptosis following extract treatment in MCF-7 (WT-p53) and MDA-MB-231 (mutant-p53) human breast cancer cell lines with a markedly reduced effect on primary human mammary epithelial cells. Analysis of p53 protein expression and of its downstream transcription targets, p21 and BAX, revealed a p53 associated growth arrest within 5 hours of extract treatment and apoptosis within 24 hours. DNA double strand breaks measured as γ-H2AX were detected early in both MCF-7 and MDA-MB-231 cells. However, loss of cell viability was only partly due to a p53-driven response; as MDA-MB-231 and p53-knockdown MCF-7 cells both underwent cell cycle arrest and death following extract treatment. p53-independent growth arrest and cytotoxicity following DNA damage has been previously ascribed to FOXO3a expression. Here, in MCF-7 and MDA-MB-231 cells, FOXO3a expression was increased significantly within 3 hours of extract treatment and FOXO3 siRNA reduced the extract-induced loss of cell viability in both cell lines.

CONCLUSIONS/SIGNIFICANCE

Our results demonstrate for the first time that an aqueous extract of Fagonia cretica can induce cell cycle arrest and apoptosis via p53-dependent and independent mechanisms, with activation of the DNA damage response. We also show that FOXO3a is required for activity in the absence of p53. Our findings indicate that Fagonia cretica aqueous extract contains potential anti-cancer agents acting either singly or in combination against breast cancer cell proliferation via DNA damage-induced FOXO3a and p53 expression.