DYRK2 controls a key regulatory network in chronic myeloid leukemia stem cells

CircCOX6A1 suppresses osteogenic differentiation and aggravates osteoporosis via miR-512-3p/DYRK2 axis

BACKGROUND

Osteoporosis (OP), characterized by compromised bone integrity and increased fracture risk, poses a significant health challenge. Circular RNAs (circRNAs) have emerged as crucial regulators in various pathophysiological processes, prompting investigation into their role in osteoporosis. This study aimed to elucidate the involvement of circCOX6A1 in OP progression and understand its underlying molecular mechanisms. The primary objective was to explore the impact of circCOX6A1 on bone marrow-derived mesenchymal stem cells (BMSCs) and its potential interactions with miR-512-3p and DYRK2.

METHODS

GSE161361 microarray analysis was employed to assess circCOX6A1 expression in OP patients. We utilized in vitro and in vivo models, including BMSC cultures, osteogenic differentiation assays, and an OVX-induced mouse model of OP. Molecular techniques such as quantitative RT-PCR, western blotting, and functional assays like alizarin red staining (ARS) were employed to evaluate circCOX6A1 effects on BMSC proliferation, apoptosis, and osteogenic differentiation. The interaction between circCOX6A1, miR-512-3p, and DYRK2 was investigated through dual luciferase reporter assays, RNA immunoprecipitation, and RNA pull-down assays.

RESULTS

CircCOX6A1 was found to be upregulated in osteoporosis patients, and its expression inversely correlated with osteogenic differentiation of BMSCs. CircCOX6A1 knockdown enhanced osteogenic differentiation, as evidenced by increased mineralized nodule formation and upregulation of osteogenic markers. In vivo, circCOX6A1 knockdown ameliorated osteoporosis progression in OVX mice. Mechanistically, circCOX6A1 acted as a sponge for miR-512-3p, subsequently regulating DYRK2 expression.

CONCLUSION

This study provides compelling evidence for the role of circCOX6A1 in osteoporosis pathogenesis. CircCOX6A1 negatively regulates BMSC osteogenic differentiation through the miR-512-3p/DYRK2 axis, suggesting its potential as a therapeutic target for mitigating OP progression.

Functional Roles of DYRK2 as a Tumor Regulator

The dual-specificity tyrosine phosphorylation-regulated kinase 2 (DYRK2) regulates the induction of apoptosis and DNA repair, metastasis inhibition, cell cycle G1/S transition, protein scaffold stability for E3 ligase complexes, and embryogenesis. Owing to these functions, DYRK2 is thought to regulate tumorigenesis, and its function in cancer has been investigated. Notably, DYRK2 has been reported to function as a tumor suppressor; however, it has also been reported to act as an oncogene in some cancers. This discrepancy makes it difficult to elucidate the conserved functions of DYRK2 in cancer. Here, we reviewed the functions of DYRK2 in various cancers. Patient tissue samples were evaluated for each cancer type. Although some studies have used cell lines and/or xenografts to elucidate the mechanism of DYRK2 function, these studies are not sufficient to understand the role of DYRK2 in cancers. In particular, studies using genetically modified mice would help us to understand the reported functional duality of DYRK2 in cancer.

O-methylated flavonol as a multi-kinase inhibitor of leukemogenic kinases exhibits a potential treatment for acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous disease with poor overall survival characterized by various genetic changes. The continuous activation of oncogenic pathways leads to the development of drug resistance and limits current therapeutic efficacy. Therefore, a multi-targeting inhibitor may overcome drug resistance observed in AML treatment. Recently, groups of flavonoids, such as flavones and flavonols, have been shown to inhibit a variety of kinase activities, which provides potential opportunities for further anticancer applications.

PURPOSE

In this study, we evaluated the anticancer effects of flavonoid compounds collected from our in-house library and investigated their potential anticancer mechanisms by targeting multiple kinases for inhibition in AML cells.

METHODS

The cytotoxic effect of the compounds was detected by cell viability assays. The kinase inhibitory activity of the selected compound was detected by kinase-based and cell-based assays. The binding conformation and interactions were investigated by molecular docking analysis. Flow cytometry was used to evaluate the cell cycle distribution and cell apoptosis. The protein and gene expression were estimated by western blotting and qPCR, respectively.

RESULTS

In this study, an O-methylated flavonol (compound 11) was found to possess remarkable cytotoxic activity against AML cells compared to treatment in other cancer cell lines. The compound was demonstrated to act against multiple kinases, which play critical roles in survival signaling in AML, including FLT3, MNK2, RSK, DYRK2 and JAK2 with IC₅₀ values of 1 - 2 μM. Compared to our previous flavonoid compounds, which only showed inhibitions against MNKs or FLT3, compound 11 exhibited multiple kinase inhibitory abilities. Moreover, compound 11 showed effectiveness in inhibiting internal tandem duplications of FLT3 (FLT3-ITDs), which accounts for 25% of AML cases. The interactions between compound 11 and targeted kinases were investigated by molecular docking analysis. Mechanically, compound 11 caused dose-dependent accumulation of leukemic cells at the G₀/G₁ phase and followed by the cells undergoing apoptosis.

CONCLUSION

O-methylated flavonol, compound 11, can target multiple kinases, which may provide potential opportunities for the development of novel therapeutics for drug-resistant AMLs. This work provides a good starting point for further compound optimization.

Kinase DYRK2 acts as a regulator of autophagy and an indicator of favorable prognosis in gastric carcinoma

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide; therefore, new and more specific molecules for GC are needed. Here, we found that dual specificity tyrosine phosphorylation regulated kinase 2 (DYRK2) may be a specific marker for GC. Immunohistochemistry (IHC) and statistical and bioinformatics analyses were conducted to detect DYRK2 expression in stomach tissues. The role of DYRK2 in GC was analyzed with a nude mouse model and CCK-8, wound healing and Transwell assays. Western blotting and immunofluorescence experiments were also performed to elucidate the relationship between DYRK2 expression and both epithelial-mesenchymal transition (EMT) and autophagy progression. We found that DYRK2 expression in GC tissues was lower than that in benign or normal tissues, and patients with high DYRK2 expression had a good prognosis. The in vitro results showed that DYRK2 expression inhibited the tumorigenic activities of GC, including proliferation, migration, and invasion. By analyzing the expression of EMT markers after altering DYRK2 expression, we observed that DYRK2 inhibits the occurrence of EMT. The nude mouse model revealed that DYRK2 inhibits tumor growth. Finally, we used Western blotting and immunofluorescence assays and found that DYRK2 promotes autophagy. Based on these data, DYRK2 may be a good reference indicator for the clinical diagnosis of GC.

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.