Overexpression of NIMA-related kinase 2 is associated with poor prognoses in malignant glioma

CCNA2 and NEK2 regulate glioblastoma progression by targeting the cell cycle

Glioblastoma (GBM) is characterized by significant heterogeneity, leading to poor survival outcomes for patients, despite the implementation of comprehensive treatment strategies. The roles of cyclin A2 (CCNA2) and NIMA related kinase 2 (NEK2) have been extensively studied in numerous cancers, but their specific functions in GBM remain to be elucidated. The present study aimed to investigate the potential molecular mechanisms of CCNA2 and NEK2 in GBM. CCNA2 and NEK2 expression and prognosis in glioma were evaluated by bioinformatics methods. In addition, the distribution of CCNA2 and NEK2 expression in GBM subsets was determined using pseudo-time analysis and tricycle position of single-cell sequencing. Gene Expression Omnibus and Kyoto Encyclopedia of Genes and Genome databases were employed and enrichment analyses were conducted to investigate potential signaling pathways in GBM subsets and a nomogram was established to predict 1-, 2- and 3-year overall survival probability in GBM. CCNA2 and NEK2 expression levels were further validated by western blot analysis and immunohistochemical staining in GBM samples. High expression of CCNA2 and NEK2 in glioma indicates poor clinical outcomes. Single-cell sequencing of GBM revealed that these genes were upregulated in a subset of positive neural progenitor cells (P-NPCs), which showed significant proliferation and progression properties and may activate G2M checkpoint pathways. A comprehensive nomogram predicts 1-, 2- and 3-year overall survival probability in GBM by considering P-NPCs, age, chemotherapy and radiotherapy scores. CCNA2 and NEK2 regulate glioblastoma progression by targeting the cell cycle, thus indicating the potential of novel therapy directed to CCNA2 and NEK2 in GBM.

TIMP1/CHI3L1 facilitates glioma progression and immunosuppression via NF-κB activation

Gliomas are highly heterogeneous brain tumours that are resistant to therapies. The molecular signatures of gliomas play a high-ranking role in tumour prognosis and treatment. In addition, patients with gliomas with a mesenchymal phenotype manifest overpowering immunosuppression and sophisticated resistance to treatment. Thus, studies on gene/protein coexpression networks and hub genes in gliomas holds promise in determining effective treatment strategies. Therefore, in this study, we aimed to. Using average linkage hierarchical clustering, 13 modules and 224 hub genes were described. Top ten hub genes (CLIC1, EMP3, TIMP1, CCDC109B, CASP4, MSN, ANXA2P2, CHI3L1, TAGLN2, S100A11), selected from the most meaningful module, were associated with poor prognosis. String analysis, co-immunoprecipitation and immunofluorescence revealed a significant correlation between TIMP1 and CHI3L1. Furthermore, we found, both in vivo and in vitro, that TIMP1 promoted gliomagenesis via CHI3L1 overexpression as well as NF-κB activation. TIMP1 expression correlated with tumour immune infiltration and immune checkpoint-related gene expression. In addition, TIMP1 resulted in immunosuppressive macrophage polarization. In summary, TIMP1/CHI3L1 might be perceived as a diagnostic marker and an immunotherapy target for gliomas.

Proteomic and metabolomic signatures of U87 glioblastoma cells treated with cisplatin and/or paclitaxel

BACKGROUND

Glioblastoma (GBM) is a primary malignancy of the central nervous system and is classified as a grade IV astrocytoma by the World Health Organization (WHO). Although GBM rarely metastasizes, its prognosis remains poor. Moreover, the standard treatment for GBM, temozolomide (TMZ), is associated with chemoresistance, which is a major factor behind GBM-related deaths. Investigating drugs with repurposing potential in the context of GBM is worthwhile to bypass lengthy bench-to-bedside research. The field of omics has garnered significant interest in scientific research because of its potential to delineate the intricate regulatory network underlying tumor development. In particular, proteomic and metabolomic analyses are powerful approaches for the investigation of metabolic enzymes and intermediate metabolites since they represent the functional end of the cancer phenotype.

METHODS

We chose two of the most widely prescribed anticancer drugs, cisplatin and paclitaxel. To our knowledge, the current literature lacks studies examining their effects on metabolic and proteomic alterations in GBM. We employed the mass spectrometry technological platform 'UHPLC-Q-TOF-MS/MS' to examine the changes in the proteome and metabolome profiles of the U87 cell line with defined concentrations of cisplatin and/or paclitaxel via an untargeted approach.

RESULTS

A total of 1,419 distinct proteins and 90 metabolites were generated, and subsequent analysis was performed. We observed that upon treatment with cisplatin (9.5 μM), U87 cells exhibited apparent efforts to cope with this exogenous stressor, understanding the effect of paclitaxel (5.3 μM) on altering the transport machinery of the cell, and how the combination of cisplatin and/or paclitaxel suggests potential interactions with promising benefits in GBM therapeutics.

CONCLUSION

Our research provides a detailed map of alterations in response to cisplatin and paclitaxel treatment, provides crucial insights into the molecular basis of their action, and paves the way for further research to identify molecular targets for this elusive malignancy.

Siglec15 is a prognostic indicator and a potential tumor-related macrophage regulator that is involved in the suppressive immunomicroenvironment in gliomas

Background

Siglec15 is rising as a promising immunotherapeutic target in bladder, breast, gastric, and pancreatic cancers. The aim of the present study is to explore the prognostic value and immunotherapeutic possibilities of Siglec15 in gliomas using bioinformatics and clinicopathological methods.

Methods

The bioinformatics approach was used to examine Siglec15 mRNA expression in gliomas based on TCGA, CGGA, and GEO datasets. Then, the predictive value of Siglec15 expression on progression-free survival time (PFST) and overall survival time (OST) in glioma patients was comprehensively described.The TCGA database was screened for differentially expressed genes (DEGs) between the high and low Siglec15 expression groups, and enrichment analysis of the DEGs was performed. The Siglec15 protein expression and its prognostic impact in 92 glioma samples were explored using immunohistochemistry Next, the relationships between Siglec15 expression and infiltrating immune cells, immune regulators and multiple immune checkpoints were analysed.

Results

Bioinformatics analyses showed that high Siglec15 levels predicted poor clinical prognosis and adverse recurrence time in glioma patients. In the immunohistochemical study serving as a validation set, Siglec15 protein overexpression was found in 33.3% (10/30) of WHO grade II, 56% (14/25) of WHO grade III, and 70.3% (26/37) of WHO grade IV gliomas respectively. Siglec15 protein overexpression was also found to be an independent prognostic indicator detrimental to the PFST and OST of glioma patients. Enrichment analysis showed that the DEGs were mainly involved in pathways associated with immune function, including leukocyte transendothelial migration, focal adhesion, ECM receptor interaction, and T-cell receptor signaling pathways. In addition, high Siglec15 expression was related to M2 tumor-associated macrophages (TAMs), N2 tumor-infiltrating neutrophils, suppressive tumor immune microenvironment, and multiple immune checkpoint molecules. Immunofluorescence analysis confirmed the colocalization of Siglec15 and CD163 on TAMs.

Conclusion

Siglec15 overexpression is common in gliomas and predicts an adverse recurrence time and overall survival time. Siglec15 is a potential target for immunotherapy and a potential TAMs regulator that is involved in the suppressed immunomicroenvironment in gliomas.

Identification of a novel spirocyclic Nek2 inhibitor using high throughput virtual screening

NIMA Related Kinase 2 (Nek2) kinase is an attractive target for the development of therapeutic agents for several types of highly invasive cancers. Despite this, no small molecule inhibitor has advanced to the late clinical stages thus far. In this work, we have identified a novel spirocyclic inhibitor (V8) of Nek2 kinase, utilizing a high-throughput virtual screening (HTVS) approach. Using recombinant Nek2 enzyme assays, we show that V8 can inhibit Nek2 kinase activity (IC50 = 2.4 ± 0.2 µM) by binding to the enzyme's ATP pocket. The inhibition is selective, reversible and is not time dependent. To understand the key chemotype features responsible for Nek2 inhibition, a detailed structure-activity relationships (SAR) was performed. Using molecular models of the energy-minimized structures of Nek2-inhibitory complexes, we identify key hydrogen-bonding interactions, including two from the hinge-binding region, likely responsible for the observed affinity. Finally, using cell-based studies, we show that V8 attenuates (a) pAkt/PI3 Kinase signaling in a dose-dependent manner, and (b) proliferative and migratory phenotypes of highly aggressive human MDA-MB-231 breast and A549 lung cancer cell lines. Thus, V8 is an important novel lead compound for the development of highly potent and selective Nek2 inhibitory agents.

Ethnic and racial-specific differences in levels of centrosome-associated mitotic kinases, proliferative and epithelial-to-mesenchymal markers in breast cancers

Molecular epidemiology evidence indicates racial and ethnic differences in the aggressiveness and survival of breast cancer. Hispanics/Latinas (H/Ls) and non-Hispanic Black women (NHB) are at higher risk of breast cancer (BC)-related death relative to non-Hispanic white (NHW) women in part because they are diagnosed with hormone receptor-negative (HR) subtype and at higher stages. Since the cell cycle is one of the most commonly deregulated cellular processes in cancer, we propose that the mitotic kinases TTK (or Mps1), TBK1, and Nek2 could be novel targets to prevent breast cancer progression among NHBs and H/Ls. In this study, we calculated levels of TTK, p-TBK1, epithelial (E-cadherin), mesenchymal (Vimentin), and proliferation (Ki67) markers through immunohistochemical (IHC) staining of breast cancer tissue microarrays (TMAs) that includes samples from 6 regions in the Southeast of the United States and Puerto Rico -regions enriched with NHB and H/L breast cancer patients. IHC analysis showed that TTK, Ki67, and Vimentin were significantly expressed in triple-negative (TNBC) tumors relative to other subtypes, while E-cadherin showed decreased expression. TTK correlated with all of the clinical variables but p-TBK1 did not correlate with any of them. TCGA analysis revealed that the mRNA levels of multiple mitotic kinases, including TTK, Nek2, Plk1, Bub1, and Aurora kinases A and B, and transcription factors that are known to control the expression of these kinases (e.g. FoxM1 and E2F1-3) were upregulated in NHBs versus NHWs and correlated with higher aneuploidy indexes in NHB, suggesting that these mitotic kinases may be future novel targets for breast cancer treatment in NHB women.

Never in Mitosis Kinase 2 regulation of metabolism is required for neural differentiation

Wnt and Hh are known signalling pathways involved in neural differentiation and recent work has shown the cell cycle regulator, Never in Mitosis Kinase 2 (Nek2) is able to regulate both pathways. Despite its known function in pathway regulation, few studies have explored Nek2 within embryonic development. The P19 embryonal carcinoma cell model was used to investigate Nek2 and neural differentiation through CRISPR knockout and overexpression studies. Loss of Nek2 reduced cell proliferation in the undifferentiated state and during directed differentiation, while overexpression increased cell proliferation. Despite these changes in proliferation rates, Nek2 deficient cells maintained pluripotency markers after neural induction while Nek2 overexpressing cells lost these markers in the undifferentiated state. Nek2 deficient cells lost the ability to differentiate into both neurons and astrocytes, although Nek2 overexpressing cells enhanced neuron differentiation at the expense of astrocytes. Hh and Wnt signalling were explored, however there was no clear connection between Nek2 and these pathways causing the observed changes to differentiation phenotypes. Mass spectrometry was also used during wildtype and Nek2 knockout cell differentiation and we identified reduced electron transport chain components in the knockout population. Immunoblotting confirmed the loss of these components and additional studies showed cells lacking Nek2 were exclusively glycolytic. Interestingly, hypoxia inducible factor 1α was stabilized in these Nek2 knockout cells despite culturing them under normoxic conditions. Since neural differentiation requires a metabolic switch from glycolysis to oxidative phosphorylation, we propose a mechanism where Nek2 prevents HIF1α stabilization, thereby allowing cells to use oxidative phosphorylation to facilitate neuron and astrocyte differentiation.

Mechanism of action of paclitaxel for treating glioblastoma based on single-cell RNA sequencing data and network pharmacology

Paclitaxel is an herbal active ingredient used in clinical practice that shows anti-tumor effects. However, its biological activity, mechanism, and cancer cell-killing effects remain unknown. Information on the chemical gene interactions of paclitaxel was obtained from the Comparative Toxicogenomics Database, SwishTargetPrediction, Binding DB, and TargetNet databases. Gene expression data were obtained from the GSE4290 dataset. Differential gene analysis, Kyoto Encyclopedia of Genes and Genomes, and Gene Ontology analyses were performed. Gene set enrichment analysis was performed to evaluate disease pathway activation; weighted gene co-expression network analysis with diff analysis was used to identify disease-associated genes, analyze differential genes, and identify drug targets via protein-protein interactions. The Molecular Complex Detection (MCODE) analysis of critical subgroup networks was conducted to identify essential genes affected by paclitaxel, assess crucial cluster gene expression differences in glioma versus standard samples, and perform receiver operator characteristic mapping. To evaluate the pharmacological targets and signaling pathways of paclitaxel in glioblastoma, the single-cell GSE148196 dataset was acquired from the Gene Expression Omnibus database and preprocessed using Seurat software. Based on the single-cell RNA-sequencing dataset, 24 cell clusters were identified, along with marker genes for the two different cell types in each cluster. Correlation analysis revealed that the mechanism of paclitaxel treatment involves effects on neurons. Paclitaxel may affect glioblastoma by improving glucose metabolism and processes involved in modulating immune function in the body.

One shoot, three birds: Targeting NEK2 orchestrates chemoradiotherapy, targeted therapy, and immunotherapy in cancer treatment

Combinational therapy has improved the cancer therapeutic landscape but is associated with a concomitant increase in adverse side reactions. Emerging evidence proposes that targeting one core target with multiple critical roles in tumors can achieve combined anti-tumor effects. This review focuses on NEK2, a member of serine/threonine kinases, with broad sequence identity to the mitotic regulator NIMA of the filamentous fungus Aspergillus nidulans. Elevated expression of NEK2 was initially found to promote tumorigeneses through abnormal regulation of the cell cycle. Subsequent studies report that NEK2 is overexpressed in a broad spectrum of tumor types and is associated with tumor progression and therapeutic resistance. Intriguingly, NEK2 has recently been revealed to mediate tumor immune escape by stabilizing the expression of PD-L1. Targeting NEK2 is thus becoming a promising approach for cancer treatment by orchestrating chemoradiotherapy, targeted therapy, and immunotherapy. It represents a novel strategy for inducing combined anti-cancer effects using a mono-agent.

NEK2 enhances malignancies of glioblastoma via NIK/NF-κB pathway

Glioblastoma (GBM) is one of the most lethal primary brain tumor with a poor median survival less than 15 months. Despite the development of the clinical strategies over the decades, the outcomes for GBM patients remain dismal due to the strong proliferation and invasion ability and the acquired resistance to radiotherapy and chemotherapy. Therefore, developing new biomarkers and therapeutic strategies targeting GBM is in urgent need. In this study, gene expression datasets and relevant clinical information were extracted from public cancers/glioma datasets, including TCGA, GRAVENDEEL, REMBRANDT, and GILL datasets. Differentially expressed genes were analyzed and NEK2 was picked as a candidate gene for subsequent validation. Human tissue samples and corresponding data were collected from our center and detected by immunohistochemistry analysis. Molecular biological assays and in vivo xenograft transplantation were performed to confirm the bioinformatic findings. High-throughput RNA sequencing, followed by KEGG analysis, GSEA analysis and GO analysis were conducted to identify potential signaling pathways related to NEK2 expression. Subsequent mechanism assays were used to verify the relationship between NEK2 and NF-κB signaling. Overall, we identified that NEK2 is significantly upregulated in GBM and the higher expression of NEK2 exhibited a poorer prognosis. Functionally, NEK2 knockdown attenuated cell proliferation, migration, invasion, and tumorigenesis of GBM while NEK2 overexpression promoted the GBM progression. Furthermore, High-throughput RNA sequencing and bioinformatics analysis indicated that NEK2 was positively related to the NF-κB signaling pathway in GBM. Mechanically, NEK2 activated the noncanonical NF-κB signaling pathway by phosphorylating NIK and increasing the activity and stability of NIK. In conclusion, NEK2 promoted the progression of GBM through activation of noncanonical NF-κB signaling, indicating that NEK2- NF-κB axis could be a potential drug target for GBM.

Genes of the month: H3.3 histone genes: H3F3A and H3F3B

Histones constitute the chief protein component of DNA. They help to maintain chromatin structure and regulate gene expression. The long double-stranded DNA molecule winds around histone octamers to form nucleosomes which serve the purpose of compacting DNA within the confines of the nuclear membrane. There are five major types of histones, namely H1/H5, H2, H3 and H4. H3.3 is a subtype of H3 histone and can be encoded either by the H3F3A or H3F3B genes independently. Amino acids such as lysine and arginine found in the histone tails are sites of post-translational modifications (PTMs) such as methylation and acetylation. These PTMs in histones are involved in the regulation of gene expression by chromatin remodelling and by controlling DNA methylation patterns. Mutations in histone genes can affect sites of PTMs causing changes in local and global DNA methylation status. These effects are directly linked to neoplastic transformation by altered gene expression. Recurrent H3.3 histone mutations are increasingly identified in several malignancies and developmental disorders. The following review attempts to shed light on the diseases associated with H3.3 histone mutations.

Competing Endogenous RNA Networks in Glioma

Gliomas are the most common and malignant primary brain tumors. Various hallmarks of glioma, including sustained proliferation, migration, invasion, heterogeneity, radio- and chemo-resistance, contribute to the dismal prognosis of patients with high-grade glioma. Dysregulation of cancer driver genes is a leading cause for these glioma hallmarks. In recent years, a new mechanism of post-transcriptional gene regulation was proposed, i.e., "competing endogenous RNA (ceRNA)." Long non-coding RNAs, circular RNAs, and transcribed pseudogenes act as ceRNAs to regulate the expression of related genes by sponging the shared microRNAs. Moreover, coding RNA can also exert a regulatory role, independent of its protein coding function, through the ceRNA mechanism. In the latest glioma research, various studies have reported that dysregulation of certain ceRNA regulatory networks (ceRNETs) accounts for the abnormal expression of cancer driver genes and the establishment of glioma hallmarks. These achievements open up new avenues to better understand the hidden aspects of gliomas and provide new biomarkers and potential efficient targets for glioma treatment. In this review, we summarize the existing knowledge about the concept and logic of ceRNET and highlight the emerging roles of some recently found ceRNETs in glioma progression.

Potential new targets and drugs related to histone modifications in glioma treatment

Glioma accounts for 40-50% of craniocerebral tumors, whose outcome rarely improves after standard treatment. The development of new therapeutic targets for glioma treatment has important clinical significance. With the deepening of research on gliomas, recent researchers have found that the occurrence and development of gliomas is closely associated with histone modifications, including methylation, acetylation, phosphorylation, and ubiquitination. Additionally, evidence has confirmed the close relationship between histone modifications and temozolomide (TMZ) resistance. Therefore, histone modification-related proteins have been widely recognized as new therapeutic targets for glioma treatment. In this review, we summarize the potential histone modification-associated targets and related drugs for glioma treatment. We have further clarified how histone modifications regulate the pathogenesis of gliomas and the mechanism of drug action, providing novel insights for the current clinical glioma treatment. Herein, we have also highlighted the limitations of current clinical therapies and have suggested future research directions and expected advances in potential areas of disease prognosis. Due to the complicated glioma pathogenesis, in the present review, we have acknowledged the limitations of histone modification applications in the related clinical treatment.

Checking NEKs: Overcoming a Bottleneck in Human Diseases

In previous years, several kinases, such as phosphoinositide 3-kinase (PI3K), mammalian target of rapamycin (mTOR), and extracellular-signal-regulated kinase (ERK), have been linked to important human diseases, although some kinase families remain neglected in terms of research, hiding their relevance to therapeutic approaches. Here, a review regarding the NEK family is presented, shedding light on important information related to NEKs and human diseases. NEKs are a large group of homologous kinases with related functions and structures that participate in several cellular processes such as the cell cycle, cell division, cilia formation, and the DNA damage response. The review of the literature points to the pivotal participation of NEKs in important human diseases, like different types of cancer, diabetes, ciliopathies and central nervous system related and inflammatory-related diseases. The different known regulatory molecular mechanisms specific to each NEK are also presented, relating to their involvement in different diseases. In addition, important information about NEKs remains to be elucidated and is highlighted in this review, showing the need for other studies and research regarding this kinase family. Therefore, the NEK family represents an important group of kinases with potential applications in the therapy of human diseases.

Circular RNA circPITX1 knockdown inhibits glycolysis to enhance radiosensitivity of glioma cells by miR-329-3p/NEK2 axis

Background

Numerous circular RNAs (circRNAs) have been recognized as vital modulators of human malignancies, including glioma. Whereas, the functional role of circRNA Pituitary Homeo Box 1 (circPITX1) in the radioresistance of glioma cells remains largely uncertain.

Methods

Quantitative real-time PCR (qRT-PCR) or western blot analysis was employed to examine the expression of circPITX1, microRNA (miR)-329-3p and NIMA-related kinase 2 (NEK2). 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to determine cell viability. Glycolysis was assessed by commercial kits and western blot analysis. Colony formation assay was conducted to analyze cell survival and clonogenicity capacity. The relationship among circPITX1, miR-329-3p and NEK2 was confirmed via dual-luciferase reporter assay. The in vivo function of circPITX1 was evaluated by tumor xenograft assay.

Results

Expression of circPITX1 and NEK2 was up-regulated in glioma tissues and cells, while miR-329-3p exhibited reverse trend. CircPITX1 knockdown repressed viability, glycolysis and colony formation, but promoted radiosensitivity of glioma cells, as well as inhibited tumor growth in vivo. MiR-329-3p was a target miRNA of circPITX1 and miR-329-3p deficiency reversed knockdown of circPITX1-mediated glycolysis inhibition and radioresistance reduction. MiR-329-3p exerted inhibitory effects on glycolysis and radioresistance of glioma cells by targeting NEK2. CircPITX1 facilitated NEK2 expression by sponging miR-329-3p. Glycolytic inhibitor 2-deoxy-d-glucose (2-DG) disposition weakened the promoted impact on glycolysis caused by circPITX1.

Conclusion

CircPITX1 knockdown reduced glycolysis to contribute to radiosensitivity in glioma through miR-329-3p/NEK2 axis, providing a possible mechanism of circPITX1 in the development of glioma.

Integrated Analysis To Identify Molecular Biomarkers Of High-Grade Serous Ovarian Cancer

Purpose

Ovarian cancer is the leading cause of gynecologic cancer-related death worldwide. Early diagnosis of ovarian cancer can significantly improve patient prognosis. Hence, there is an urgent need to identify key diagnostic and prognostic biomarkers specific for ovarian cancer. Because high-grade serous ovarian cancer (HGSOC) is the most common type of ovarian cancer and accounts for the majority of deaths, we identified potential biomarkers for the early diagnosis and prognosis of HGSOC.

Methods

Six datasets (GSE14001, GSE18520, GSE26712, GSE27651, GSE40595, and GSE54388) were downloaded from the Gene Expression Omnibus database for analysis. Differentially expressed genes (DEGs) between HGSOC and normal ovarian surface epithelium samples were screened via integrated analysis. Hub genes were identified by analyzing protein-protein interaction (PPI) network data. The online Kaplan-Meier plotter was utilized to evaluate the prognostic roles of these hub genes. The expression of these hub genes was confirmed with Oncomine datasets and validated by quantitative real-time PCR and Western blotting.

Results

A total of 103 DEGs in patients with HGSOC-28 upregulated genes and 75 downregulated genes-were successfully screened. Enrichment analyses revealed that the upregulated genes were enriched in cell division and cell proliferation and that the downregulated genes mainly participated in the Wnt signaling pathway and various metabolic processes. Ten hub genes were associated with HGSOC pathogenesis. Seven overexpressed hub genes were partitioned into module 1 of the PPI network, which was enriched in the cell cycle and DNA replication pathways. Survival analysis revealed that MELK, CEP55 and KDR expression levels were significantly correlated with the overall survival of HGSOC patients (P < 0.05). The RNA and protein expression levels of these hub genes were validated experimentally.

Conclusion

Based on an integrated analysis, we propose the further investigation of MELK, CEP55 and KDR as promising diagnostic and prognostic biomarkers of HGSOC.

microRNA-138 induces cell survival and reduces WNT/β-catenin signaling of osteoarthritis chondrocytes through NEK2

Osteoarthritis (OA) is a degenerative joint disease characterized by joint pain, stiffness, and function degeneration with high incidence. Recent studies have been inspired based on the association between microRNAs (miRs) and therapeutic research of OA. Hence, the present study evaluates the effects of miR-138 on chondrocyte proliferation, differentiation, and apoptosis through the WNT/β-catenin signaling pathway in mice with OA by binding to NIMA-related kinase 2 (NEK2). Appropriate dataset was selected from the Gene Expression Omnibus database, and differentially expressed genes and potential miRNAs that could regulate NEK2 were explored. A mouse model of OA was established. The expressions of miR-138, NEK2, β-catenin, GSK3β, Bcl-2, Bcl-2-associated X protein (Bax), p53, MMP-13, Col2, and Aggrecan and the phosphorylation levels of β-catenin were determined by the reverse transcription quantitative polymerase chain reaction and Western blot analysis. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and flow cytometry were employed to detect cell proliferation and apoptosis, respectively. The potential functional role of NEK2 was revealed to be related to the WNT/β-catenin signaling pathway, and miR-138 was the putative regulator of NEK2. miR-138 expression was downregulated while expressions of NEK2 and β-catenin as well as the phosphorylation levels of β-catenin were upregulated in mice with OA. The chondrocytes treated with miR-138 mimic and siRNA-NEK2 exhibited reduced expressions of NEK2, β-catenin, MMP-13, Bax, and p53 and elevated expressions of Col2, Aggrecan, and Bcl-2 as well as phosphorylation levels of β-catenin along with enhanced chondrocytes' proliferation and suppressed cell apoptosis. Overexpression of miR-138 induces cell survival and reduces WNT/β-catenin signaling of OA chondrocytes through NEK2. © 2019 IUBMB Life, 71(9):1355-1366, 2019.

CGK062, a small chemical molecule, inhibits cancer upregulated gene 2‑induced oncogenesis through NEK2 and β‑catenin

The mechanisms through which cancer‑upregulated gene 2 (CUG2), a novel oncogene, affects Wnt/β‑catenin signaling, essential for tumorigenesis, are unclear. In this study, we aimed to elucidate some of these mechanisms in A549 lung cancer cells. Under the overexpression of CUG2, the protein levels and activity of β‑catenin were evaluated by western blot analysis and luciferase assay. To examine a biological consequence of β‑catenin under CUG2 overexpression, cell migration, invasion and sphere formation assay were performed. The upregulation of β‑catenin induced by CUG2 overexpression was also accessed by xenotransplantation in mice. We first found that CUG2 overexpression increased β‑catenin expression and activity. The suppression of β‑catenin decreased cancer stem cell (CSC)‑like phenotypes, indicating that β‑catenin is involved in CUG2‑mediated CSC‑like phenotypes. Notably, CUG2 overexpression increased the phosphorylation of β‑catenin at Ser33/Ser37, which is known to recruit E3 ligase for β‑catenin degradation. Moreover, CUG2 interacted with and enhanced the expression and kinase activity of never in mitosis gene A‑related kinase 2 (NEK2). Recombinant NEK2 phosphorylated β‑catenin at Ser33/Ser37, while NEK2 knockdown decreased the phosphorylation of β‑catenin, suggesting that NEK2 is involved in the phosphorylation of β‑catenin at Ser33/Ser37. Treatment with CGK062, a small chemical molecule, which promotes the phosphorylation of β‑catenin at Ser33/Ser37 through protein kinase C (PKC)α to induce its degradation, reduced β‑catenin levels and inhibited the CUG2‑induced features of malignant tumors, including increased cell migration, invasion and sphere formation. Furthermore, CGK062 treatment suppressed CUG2‑mediated tumor formation in nude mice. Taken together, the findings of this study suggest that CUG2 enhances the phosphorylation of β‑catenin at Ser33/Ser37 by activating NEK2, thus stabilizing β‑catenin. CGK062 may thus have potential for use as a therapeutic drug against CUG2‑overexpressing lung cancer cells.

Prognostic significance of NEK2 in human solid tumors: a systematic review and meta-analysis

A consensus about the prognostic role of NIMA-related kinase 2 (NEK2) expression in various solid tumors has not been made yet. Thus, this meta-analysis aimed to systematically assess the prognostic role of NEK2 expression in patients with solid tumors. The eligible studies were identified through searching PubMed, Web of Science, and EMBASE. The hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were used to evaluate the link between NEK2 overexpression and overall survival (OS) and disease-free survival/recurrence-free survival (DFS/RFS) of patients with solid tumors. A total of 17 studies with 4897 patients were included in this meta-analysis. Among these studies, all of them explored the association between NEK2 expression and OS of patients with solid tumors. Our pooled analysis indicated that NEK2 overexpression was significantly related to adverse OS (HR = 1.66; 95% CI: 1.38–2.00; P = 0.001). Additionally, there were six studies with 854 patients that investigated the association between NEK2 expression and DFS/RFS. Our pooled result indicated that there was a substantial relationship between NEK2 overexpression and poorer DFS/RFS (HR = 2.00; 95% CI: 1.61–2.48; P = 0.003). In conclusion, our meta-analysis indicated that NEK2 may be a useful predictor of prognosis and an effective therapeutic target in solid tumors. Nevertheless, more high-quality studies are warranted to further support our conclusions because of several limitations in our meta-analysis.

NIMA-related kinase 2 overexpression is associated with poor survival in cancer patients: a systematic review and meta-analysis

Objective

NIMA-related kinase 2 (NEK2) has been reported to be overexpressed in various types of cancer and correlated with poor prognosis. The role(s) of NEK2 in cancer, however, is still uncertain. The aim of this study was to evaluate the prognostic value of NEK2 in human tumors.

Methods

A comprehensive literature search was performed for PubMed, Embase, Web of Science, and CNKI databases, and eligible studies were included based on the inclusion and exclusion criteria. A meta-analysis of the included studies was then carried out.

Results

Fifteen studies with 3,280 cancer patients were included in the present meta-analysis. All publications were of moderate to high quality, and had no significant heterogeneity (I^2=46%, P=0.03) or publication bias was discovered. The results showed that a high NEK2 level was associated with shorter overall survival (OS) in patients with various types of cancers (pooled HR=1.72, 95% CI 1.49–2.00, P<0.00001). However, the disease-free survival (DFS) had no significant association with NEK2 level (HR=1.13, 95% CI: 0.29–4.38, P=0.85). In the subgroup analyses, high NEK2 level was correlated with an increased risk of poor OS in patients with hepatocellular carcinoma (HR=1.62, 95% CI: 1.25–2.10, P=0.02) and lung cancer (HR=2.18, 95% CI: 1.40–3.38, P=0.0005). However, other factors, including sample size, follow-up period, HR estimation method, and country, also affect the association between NEK2 expression and OS. Analysis of clinicopathological parameters further showed that increased NEK2 level was correlated with younger age, male gender, better tumor differentiation, and lower number of tumor nodules.

Conclusion

The results of this study indicated that increased expression of NEK2 was associated with unfavorable survival of cancer patients and that NEK2 could be used as a prognostic predictor for cancers.