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

Mirk/Dyrk1B Kinase Inhibitors in Targeted Cancer Therapy

During the last years, there has been an increased effort in the discovery of selective and potent kinase inhibitors for targeted cancer therapy. Kinase inhibitors exhibit less toxicity compared to conventional chemotherapy, and several have entered the market. Mirk/Dyrk1B kinase is a promising pharmacological target in cancer since it is overexpressed in many tumors, and its overexpression is correlated with patients' poor prognosis. Mirk/Dyrk1B acts as a negative cell cycle regulator, maintaining the survival of quiescent cancer cells and conferring their resistance to chemotherapies. Many studies have demonstrated the valuable therapeutic effect of Mirk/Dyrk1B inhibitors in cancer cell lines, mouse xenografts, and patient-derived 3D-organoids, providing a perspective for entering clinical trials. Since the majority of Mirk/Dyrk1B inhibitors target the highly conserved ATP-binding site, they exhibit off-target effects with other kinases, especially with the highly similar Dyrk1A. In this review, apart from summarizing the data establishing Dyrk1B as a therapeutic target in cancer, we highlight the most potent Mirk/Dyrk1B inhibitors recently reported. We also discuss the limitations and perspectives for the structure-based design of Mirk/Dyrk1B potent and highly selective inhibitors based on the accumulated structural data of Dyrk1A and the recent crystal structure of Dyrk1B with AZ191 inhibitor.

Pathogenic, Total Loss-of-Function DYRK1B Variants Cause Monogenic Obesity Associated With Type 2 Diabetes

OBJECTIVE

Rare variants in DYRK1B have been described in some patients with central obesity, type 2 diabetes, and early-onset coronary disease. Owing to the limited number of conducted studies, the broader impact of DYRK1B variants on a larger scale has yet to be investigated.

RESEARCH DESIGN AND METHODS

DYRK1B was sequenced in 9,353 participants from a case-control study for obesity and type 2 diabetes. Each DYRK1B variant was functionally assessed in vitro. Variant pathogenicity was determined using criteria from the American College of Medical Genetics and Genomics (ACMG). The effect of pathogenic or likely pathogenic (P/LP) variants on metabolic traits was assessed using adjusted mixed-effects score tests.

RESULTS

Sixty-five rare, heterozygous DYRK1B variants were identified and were not associated with obesity or type 2 diabetes. Following functional analyses, 20 P/LP variants were pinpointed, including 6 variants that exhibited a fully inhibitory effect (P/LP-null) on DYRK1B activity. P/LP and P/LP-null DYRK1B variants were associated with increased BMI and obesity risk; however, the impact was notably more pronounced for the P/LP-null variants (effect of 8.0 ± 3.2 and odds ratio of 7.9 [95% CI 1.2-155]). Furthermore, P/LP-null variants were associated with higher fasting glucose and type 2 diabetes risk (effect of 2.9 ± 1.0 and odds ratio of 4.8 [95% CI 0.85-37]), while P/LP variants had no effect on glucose homeostasis.

CONCLUSIONS

P/LP, total loss-of-function DYRK1B variants cause monogenic obesity associated with type 2 diabetes. This study underscores the significance of conducting functional assessments in order to accurately ascertain the tangible effects of P/LP DYRK1B variants.

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.

DYRK1B haploinsufficiency in a Holstein cattle with epilepsy

In this study, epilepsy with focal seizures progressing to generalized seizures was diagnosed in a 6-month-old Holstein heifer. The seizures were characterized by a brief pre-ictal phase with depression and vocalization. During the ictal phase eyelid spasms, tongue contractions, nodding and abundant salivation were observed, rapidly followed by a convulsive phase with bilateral tonic, clonic or tonic-clonic activity and loss of consciousness. Finally, during the postictal phase the heifer was obtunded and disorientated, unable to perceive obstacles and hypermetric, and pressed its head against objects. In the inter-seizure phase, the heifer was clinically normal. Neuropathology revealed axonal degeneration in the brainstem and diffuse astrocytic hypertrophic gliosis. Whole genome sequencing of the affected heifer identified a private heterozygous splice-site variant in DYRK1B (NM_001081515.1: c.-101-1G>A), most likely resulting in haploinsufficiency owing to loss-of-function. This represents a report of a DYRK1B-associated disease in cattle and adds DYRK1B to the candidate genes for epilepsy.

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 FOXO1^Ser329 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.

Analysis of DYRK1B, PPARG, and CEBPB Expression Patterns in Adipose-Derived Stem Cells from Patients Carrying DYRK1B R102C and Healthy Individuals During Adipogenesis

Background: Metabolic syndrome (MetS) is a group of signs and symptoms that are associated with a higher risk of type 2 diabetes mellitus and cardiovascular diseases. The major risk factor for developing MetS is abdominal obesity, which is caused by an increase in adipocyte size or quantity. Increased adipocyte quantity is a result of differentiation of stem cells into adipose tissue. Numerous studies have investigated the expression of key transcription factors, including PPARG and CEBPB during adipocyte differentiation in murine cells such as 3T3-L1 cell lines. To better understand the expression changes during the process of fat accumulation in adipose-derived stem cells (ASCs), we compared the expression of DYRK1B, PPARG, and ẟB in ASCs between the patient (harboring DYRK1B R102C) and control (healthy individuals) groups. Methods: Gene expression was evaluated on the eighth day before induction and days 1, 5, and 15 postinduction. The pluripotent capacity of ASCs and the potential for differentiation into adipocytes were confirmed by flow cytometry analysis of surface markers (CD34, CD44, CD105, and CD90), and Oil Red O staining, respectively. The Expression of DYRK1B, PPARG, and CEBPB were assessed by real-time-polymerase chain reaction in patients and normal individuals. The effects of AZ191, a potent small molecule inhibitor on DYRK1B and CEBPB expression in patients' samples were studied. Result: The expression of DYRK1B kinase and transcription factors (CEBPB and PPARG) are higher in ASCs harboring DYRK1B R102C compared with noncarriers on days 5 and 15 during adipocyte differentiation. These proteins may be helpful to elucidate the mechanisms underlying obesity and obesity-related disorders like MetS. Furthermore, the new compound AZ191 exhibited inhibitory activity toward DYRK1B and CEBPB. We suggest that AZ191 may be helpful in defining the potential roles of DYRK1B and CEBPB in adipogenesis.

Dual-Specificity, Tyrosine Phosphorylation-Regulated Kinases (DYRKs) and cdc2-Like Kinases (CLKs) in Human Disease, an Overview

Dual-specificity tyrosine phosphorylation-regulated kinases (DYRK1A, 1B, 2-4) and cdc2-like kinases (CLK1-4) belong to the CMGC group of serine/threonine kinases. These protein kinases are involved in multiple cellular functions, including intracellular signaling, mRNA splicing, chromatin transcription, DNA damage repair, cell survival, cell cycle control, differentiation, homocysteine/methionine/folate regulation, body temperature regulation, endocytosis, neuronal development, synaptic plasticity, etc. Abnormal expression and/or activity of some of these kinases, DYRK1A in particular, is seen in many human nervous system diseases, such as cognitive deficits associated with Down syndrome, Alzheimer's disease and related diseases, tauopathies, dementia, Pick's disease, Parkinson's disease and other neurodegenerative diseases, Phelan-McDermid syndrome, autism, and CDKL5 deficiency disorder. DYRKs and CLKs are also involved in diabetes, abnormal folate/methionine metabolism, osteoarthritis, several solid cancers (glioblastoma, breast, and pancreatic cancers) and leukemias (acute lymphoblastic leukemia, acute megakaryoblastic leukemia), viral infections (influenza, HIV-1, HCMV, HCV, CMV, HPV), as well as infections caused by unicellular parasites (Leishmania, Trypanosoma, Plasmodium). This variety of pathological implications calls for (1) a better understanding of the regulations and substrates of DYRKs and CLKs and (2) the development of potent and selective inhibitors of these kinases and their evaluation as therapeutic drugs. This article briefly reviews the current knowledge about DYRK/CLK kinases and their implications in human disease.

Resveratrol and Its Analogs: Potent Agents to Reverse Epithelial-to-Mesenchymal Transition in Tumors

Epithelial-to-mesenchymal transition (EMT), a complicated program through which polarized epithelial cells acquire motile mesothelial traits, is regulated by tumor microenvironment. EMT is involved in tumor progression, invasion and metastasis via reconstructing the cytoskeleton and degrading the tumor basement membrane. Accumulating evidence shows that resveratrol, as a non-flavonoid polyphenol, can reverse EMT and inhibit invasion and migration of human tumors via diverse mechanisms and signaling pathways. In the present review, we will summarize the detailed mechanisms and pathways by which resveratrol and its analogs (e.g. Triacetyl resveratrol, 3,5,4'-Trimethoxystilbene) might regulate the EMT process in cancer cells to better understand their potential as novel anti-tumor agents. Resveratrol can also reverse chemoresistance via EMT inhibition and improvement of the antiproliferative effects of conventional treatments. Therefore, resveratrol and its analogs have the potential to become novel adjunctive agents to inhibit cancer metastasis, which might be partly related to their blocking of the EMT process.