Upregulation of the cycline kinase subunit CKS2 increases cell proliferation rate in gastric cancer. J Cancer Res Clin Oncol. 2009;135:761-769. [PMID: 19034516 DOI: 10.1007/s00432-008-0510-3]

Biological functions and therapeutic potential of CKS2 in human cancer

The incidence of cancer is increasing worldwide and is the most common cause of death. Identification of novel cancer diagnostic and prognostic biomarkers is important for developing cancer treatment strategies and reducing mortality. Cyclin-dependent kinase subunit 2 (CKS2) is involved in cell cycle and proliferation processes, and based on these processes, CKS2 was identified as a cancer gene. CKS2 is expressed in a variety of tissues in the human body, but its abnormal expression is associated with cancer in a variety of systems. CKS2 is generally elevated in cancer, plays a role in almost all aspects of cancer biology (such as cell proliferation, invasion, metastasis, and drug resistance) through multiple mechanisms regulating certain important genes, and is associated with clinicopathological features of patients. In addition, CKS2 expression patterns are closely related to cancer type, stage and other clinical variables. Therefore, CKS2 is considered as a tool for cancer diagnosis and prognosis and may be a promising tumor biomarker and therapeutic target. This article reviews the biological function, mechanism of action and potential clinical significance of CKS2 in cancer, in order to provide a new theoretical basis for clinical molecular diagnosis, molecular targeted therapy and scientific research of cancer.

Prognostic significance of cyclin-dependent kinase subunit 2 (CKS2) in malignant tumours: a meta-analysis and bioinformatic analysis

OBJECTIVES

This study aimed to systematically elucidate the prognostic significance of cyclin-dependent kinase subunit 2 (CKS2) expression in various cancers and its correlation with their clinicopathological characteristics.

DESIGN

In this meta-analysis and bioinformatic analysis, articles were identified through searches of multiple databases and meta-analysed according to the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. Data from The Cancer Genome Atlas were examined using UCSC Xena tools to further confirm the prognostic effect of CKS2.

DATA SOURCES

The PubMed, Embase, Web of Science and Cochrane Library databases were searched for articles published from their inception to 1 January 2023, using a combination of subject terms and free words, including 'CKS2', 'cancer', 'tumor', 'neoplasm', 'carcinoma', 'malignancy' and 'prognosis'.

ELIGIBILITY CRITERIA

The analysis included cohort or case-control studies, reported in English, with malignancy diagnoses confirmed by pathological methods, available HRs and 95% CIs for overall survival (OS) or extractable Kaplan-Meier curves, and a sample size of ≥20 patients. Reviews, commentaries, letters, conference reports, case reports, in vitro and animal studies, studies of CKS2 gene variants, studies with sample cases from public databases and studies with unavailable survival or duplicated data were excluded.

DATA EXTRACTION AND SYNTHESIS

Two researchers independently screened the articles, extracted the data and evaluated the quality of included studies using the Newcastle-Ottawa Scale. Meta-analysis and bioinformatic analyses were performed using the STATA and R software, respectively.

RESULTS

The analysis included 13 retrospective studies encompassing 1348 cases across 10 cancer types. Nine studies involving 1124 patients examined the correlation between CKS2 expression levels and OS. A fixed-effects model analysis revealed a significant association between high CKS2 expression and reduced OS (HR=2.27, 95% CI=1.87 to 2.77, p<0.001). Furthermore, high CKS2 expression was significantly associated with advanced tumour stage (relative risk (RR) = 1.82, 95% CI=1.57 to 2.11, p<0.001), lymph node metastasis (RR=1.68, 95% CI=1.38 to 2.04, p<0.001), larger tumour size (RR=1.60, 95% CI=1.27 to 2.03, p<0.001) and lower differentiation grade (RR=1.57, 95% CI=1.29 to 1.90, p<0.001). CKS2 expression levels were not significantly correlated with patients' age (RR=1.11, 95% CI=0.99 to 1.26, p=0.071) or sex (RR=0.98, 95% CI=0.90 to 1.07, p=0.653). An assessment of the articles showed no significant publication bias, confirming the robustness of these findings. The bioinformatic analysis further confirmed CKS2 upregulation in the examined cancer types and its association with poor OS in glioma (HR=1.97, 95% CI=1.78 to 2.18, p=3.70×10-42), liver hepatocellular carcinoma (HR=1.56, 95% CI=1.31 to 1.86, p=3.50×10-7) and lung adenocarcinoma (HR=1.27, 95% CI=1.10 to 1.48, p=1.70×10-3).

CONCLUSIONS

Elevated CKS2 expression is associated with poor prognosis in a subset of malignant tumours, highlighting its potential as a prognostic marker.

PROSPERO REGISTRATION NUMBER

CRD42023394038.

Construction of hub transcription factor-microRNAs-messenger RNA regulatory network in recurrent implantation failure

PURPOSE

Recurrent implantation failure (RIF) affects up to 10% of in vitro fertilization (IVF) patients worldwide. However, the pathogenesis of RIF remains unclear. This study was aimed at identifying hub transcription factors (TFs) of RIF in bioinformatics approaches.

METHODS

The GSE111974 (mRNA), GSE71332 (miRNA), and GSE103465 (mRNA) datasets were downloaded from the Gene Expression Omnibus database from human endometrial tissue using R version 4.2.1 and used to identify differentially expressed TFs (DETFs), differentially expressed miRNAs, and differentially expressed genes for RIF, respectively. DETFs were subjected to functional enrichment analysis and the protein-protein interaction network analysis using the Search Tool for the Retrieval of Interacting Genes (version 11.5) database. Hub TFs were identified using the cytoHubb plug-in, after which a hub TF-miRNA-mRNA network was constructed using Cytoscape v3.8.2.

RESULTS

Fifty-seven DETFs were identified, in which Gene Ontology analysis revealed to be mainly involved in the regulation of transcription. Kyoto Encyclopedia of Genes and Genomes pathway analysis suggested that DETFs were enriched in transcriptional misregulation in cancer, aldosterone synthesis and secretion, AMPK signaling pathway, and cGMP-PKG signaling pathway. EOMES, NKX2-1, and POU5F1 were identified as hub TFs, and a hub TF-miRNA-mRNA regulatory network was constructed using these three hub TFs, four miRNAs, and four genes.

CONCLUSION

Collectively, we identified three promising molecular biomarkers for the diagnosis of RIF, which may further be potential therapeutic targets. This study provides novel insights into the molecular mechanisms underlying RIF. However, further experiments are required to verify these results.

Comprehensive analysis of the progression mechanisms of CRPC and its inhibitor discovery based on machine learning algorithms

Background: Almost all patients treated with androgen deprivation therapy (ADT) eventually develop castration-resistant prostate cancer (CRPC). Our research aims to elucidate the potential biomarkers and molecular mechanisms that underlie the transformation of primary prostate cancer into CRPC. Methods: We collected three microarray datasets (GSE32269, GSE74367, and GSE66187) from the Gene Expression Omnibus (GEO) database for CRPC. Differentially expressed genes (DEGs) in CRPC were identified for further analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA). Weighted gene coexpression network analysis (WGCNA) and two machine learning algorithms were employed to identify potential biomarkers for CRPC. The diagnostic efficiency of the selected biomarkers was evaluated based on gene expression level and receiver operating characteristic (ROC) curve analyses. We conducted virtual screening of drugs using AutoDock Vina. In vitro experiments were performed using the Cell Counting Kit-8 (CCK-8) assay to evaluate the inhibitory effects of the drugs on CRPC cell viability. Scratch and transwell invasion assays were employed to assess the effects of the drugs on the migration and invasion abilities of prostate cancer cells. Results: Overall, a total of 719 DEGs, consisting of 513 upregulated and 206 downregulated genes, were identified. The biological functional enrichment analysis indicated that DEGs were mainly enriched in pathways related to the cell cycle and metabolism. CCNA2 and CKS2 were identified as promising biomarkers using a combination of WGCNA, LASSO logistic regression, SVM-RFE, and Venn diagram analyses. These potential biomarkers were further validated and exhibited a strong predictive ability. The results of the virtual screening revealed Aprepitant and Dolutegravir as the optimal targeted drugs for CCNA2 and CKS2, respectively. In vitro experiments demonstrated that both Aprepitant and Dolutegravir exerted significant inhibitory effects on CRPC cells (p < 0.05), with Aprepitant displaying a superior inhibitory effect compared to Dolutegravir. Discussion: The expression of CCNA2 and CKS2 increases with the progression of prostate cancer, which may be one of the driving factors for the progression of prostate cancer and can serve as diagnostic biomarkers and therapeutic targets for CRPC. Additionally, Aprepitant and Dolutegravir show potential as anti-tumor drugs for CRPC.

Integrated Bioinformatics Investigation of Novel Biomarkers of Uterine Leiomyosarcoma Diagnosis and Outcome

Uterine leiomyosarcomas (uLMS) have a poor prognosis and a high percentage of recurrent disease. Bioinformatics has become an integral element in rare cancer studies by overcoming the inability to collect a large enough study population. This study aimed to investigate and highlight crucial genes, pathways, miRNAs, and transcriptional factors (TF) on uLMS samples from five Gene Expression Omnibus datasets and The Cancer Genome Atlas Sarcoma study. Forty-one common differentially expressed genes (DEGs) were enriched and annotated by the DAVID software. With protein-protein interaction (PPI) network analysis, we selected ten hub genes that were validated with the TNMplotter web tool. We used the USCS Xena browser for survival analysis. We also predicted TF-gene and miRNA-gene regulatory networks along with potential drug molecules. TYMS and TK1 correlated with overall survival in uLMS patients. Finally, our results propose further validation of hub genes (TYMS and TK1), miR-26b-5p, and Sp1 as biomarkers of pathogenesis, prognosis, and differentiation of uLMS. Regarding the aggressive behavior and poor prognosis of uLMS, with the lack of standard therapeutic regimens, in our opinion, the results of our study provide enough evidence for further investigation of the molecular basis of uLMS occurrence and its implication in the diagnosis and therapy of this rare gynecological malignancy.

CKS2 Promotes the Growth in Non-Small-Cell Lung Cancer by Downregulating Cyclin-Dependent Kinase Inhibitor

INTRODUCTION/OBJECTIVE

This study aimed to explore the expression of cyclin-dependent kinase subunit 2 (CKS2) in tissues and cells in non-small-cell lung cancer (NSCLC) and the function mechanism of CKS2 in NSCLC cell growth and tumorigensis.

METHODS

After transfecting NCI-H2170 cells with short-hair RNA (shRNA), an shCKS2 gene-silencing model was established. The cells were divided into a shRNA group and shNC group. For overexpression cell lines, we used the same method to establish the NCI-H2170-CKS2 cell lines. Cell Count Kit-8 assay and colony formation assay were used to determine cell viability and cell growth, respectively. Propidium iodide staining was used to determine cell cycle progression. The mRNA expression of CKS2 and protein expression of CKS2, p21, p53, and PTEN were determined by RT-qPCR and Western blotting, respectively. The expression of CKS2, p53, and Ki67 in tissues was determined by immunohistochemical stain. The in vivo tumorigenesis assays were used to determine the ability of CKS2 in tumor growth.

RESULTS

The results of RT-qPCR and Western blotting assay revealed that CKS2 upregulated expression in NSCLC tissues and cells. The results of the CCK-8 assay revealed that the shRNA group exhibited significantly lower cell viability and foci formation than the empty plasmid group, while CKS2 overexpression induces cell growth and cell cycle progression. The result of nude mice suggested that CKS2 knockdown expression suppressed tumorigenesis in the in vivo animal model.

CONCLUSIONS

Our study suggests that CKS2 could be a biomarker in the progression and prognosis of NSCLC.

LINC00657/miR-26a-5p/CKS2 ceRNA network promotes the growth of esophageal cancer cells via the MDM2/p53/Bcl2/Bax pathway

LncRNA LINC00657 has oncogenic or anti-carcinoma roles in different cancers, and yet its detailed molecular mechanism in esophageal cancer (EC) remains unclear. In addition, competitive endogenous RNA (ceRNA) regulatory lncRNA–miRNA–mRNA networks are critical for tumorigenesis and progression. Hence, the present study explored the roles of LINC00657 in EC and identified its relevant ceRNA network. We first detected the expression of LINC00657 in EC. Then, we applied starBase and TargetScan websites to find miR-26a-5p binding to LINC00657 and obtain CKS2 as a target of miR-26a-5p. The roles of LINC00657, miR-26a-5p or CKS2 in the proliferation, migration, invasion, and apoptosis of EC cells were respectively assessed by CCK-8, wound healing assay, transwell invasion assay, and flow cytometry. The changes of the MDM2/p53/Bcl2/Bax pathway were measured via Western blot. The results revealed that LINC00657 showed an aberrant high expression in EC cells, which promoted the growth of EC cells. Additionally, LINC00657 functioned as a sponge of miR-26a-5p, and LINC00657 negatively mediated miR-26a-5p to regulate the growth of EC cells. Furthermore, CKS2 was observed as a direct target of miR-26a-5p, and CKS2 controlled the growth of EC cells via the MDM2/p53/Bcl2/Bax pathway. Moreover, there was a positive correlation between LINC00657 and CKS2. LINC00657 knockdown inhibited CKS2 expression to suppress the proliferation, migration, and invasion of EC cells and induced apoptosis via regulating the MDM2/p53/Bcl2/Bax pathway. Collectively, LINC00657/miR-26a-5p/CKS2 ceRNA network could promote the progression of EC, which is good for understanding the molecular mechanism of EC and offers novel biomarkers for EC diagnosis and therapy.

Identification of potential and novel target genes in pituitary prolactinoma by bioinformatics analysis

Pituitary prolactinoma is one of the most complicated and fatally pathogenic pituitary adenomas. Therefore, there is an urgent need to improve our understanding of the underlying molecular mechanism that drives the initiation, progression, and metastasis of pituitary prolactinoma. The aim of the present study was to identify the key genes and signaling pathways associated with pituitary prolactinoma using bioinformatics analysis. Transcriptome microarray dataset GSE119063 was downloaded from Gene Expression Omnibus (GEO) database. Limma package in R software was used to screen DEGs. Pathway and Gene ontology (GO) enrichment analysis were conducted to identify the biological role of DEGs. A protein-protein interaction (PPI) network was constructed and analyzed by using HIPPIE database and Cytoscape software. Module analyses was performed. In addition, a target gene-miRNA regulatory network and target gene-TF regulatory network were constructed by using NetworkAnalyst and Cytoscape software. Finally, validation of hub genes by receiver operating characteristic (ROC) curve analysis. A total of 989 DEGs were identified, including 461 up regulated genes and 528 down regulated genes. Pathway enrichment analysis showed that the DEGs were significantly enriched in the retinoate biosynthesis II, signaling pathways regulating pluripotency of stem cells, ALK2 signaling events, vitamin D3 biosynthesis, cell cycle and aurora B signaling. Gene Ontology (GO) enrichment analysis showed that the DEGs were significantly enriched in the sensory organ morphogenesis, extracellular matrix, hormone activity, nuclear division, condensed chromosome and microtubule binding. In the PPI network and modules, SOX2, PRSS45, CLTC, PLK1, B4GALT6, RUNX1 and GTSE1 were considered as hub genes. In the target gene-miRNA regulatory network and target gene-TF regulatory network, LINC00598, SOX4, IRX1 and UNC13A were considered as hub genes. Using integrated bioinformatics analysis, we identified candidate genes in pituitary prolactinoma, which might improve our understanding of the molecular mechanisms of pituitary prolactinoma.

Identification of NDRG Family Member 4 (NDRG4) and CDC28 Protein Kinase Regulatory Subunit 2 (CKS2) as Key Prognostic Genes in Adrenocortical Carcinoma by Transcriptomic Analysis

BACKGROUND Adrenocortical carcinoma (ACC) is an aggressive cancer with heterogeneous outcomes. In this study, we aimed to investigate genomic and prognostic features of ACC. MATERIAL AND METHODS Clinical, pathologic, and transcriptomic data from 2 independent datasets derived from ACC samples (TCGA-ACC dataset, GEO-GSE76021 dataset) were collected. Weighted gene co-expression network analysis (WGCNA) and survival analyses were performed to identify prognostic genes. Pathway analysis was performed for mechanistic analysis. xCell deconvolution was performed for tumor microenvironment analysis. RESULTS In the TCGA-ACC cohort, WGCNA identified a prognostic module of 5408 genes. Differential expression analysis identified 1969 genes that differed in expression level between long-term and short-term survivors. Univariate Cox regression model analysis identified 8393 genes with prognostic value. The intersection of these gene sets included 820 prognostic genes. Similar protocols were performed for the GSE76021 dataset, and 5 candidate genes were identified. Further intersection of these genes finally identified NDRG4 and CKS2 as key prognostic genes. Multivariate Cox regression model analysis validated the prognostic value of NDRG4 (HR=0.61, 95% CI 0.46-0.80) and CKS2 (HR=2.52, 95% CI 1.38-4.60). Moreover, NDRG4 and CKS2 expression predicted survival in patients treated with mitotane (P<0.001). Further mechanism exploration found an association between CKS2 and DNA mismatch repair pathways. Moreover, NDRG4 positively correlated with CD8⁺ T cell infiltration, while CKS2 negatively correlated with it. CONCLUSIONS We identified NDRG4 and CKS2 expression as key prognostic genes in ACC, which may help in risk stratification of ACC. Moreover, a close relationship was found between CKS2 and mismatch repair pathways. Moreover, immune cell infiltration differed according to NDRG4 and CKS2 expression.

Differential gene expression in peritumoral brain zone of glioblastoma: role of SERPINA3 in promoting invasion, stemness and radioresistance of glioma cells and association with poor patient prognosis and recurrence

PURPOSE

Glioblastoma (GBM) is a highly invasive tumor. Despite advances in treatment modalities, tumor recurrence is common, seen mainly in the peritumoral brain zone (PBZ). We aimed to molecularly characterize PBZ, to understand the pathobiology of tumor recurrence.

METHODS/PATIENTS

We selected eight differentially regulated genes from our previous transcriptome profiling study on tumor core and PBZ. Expression of selected genes were validated in GBM (tumor core and PBZ, n = 37) and control (n = 22) samples by real time quantitative polymerase chain reaction (qPCR). Serine protease inhibitor clade A, member 3 (SERPINA3) was selected for further functional characterization in vitro by gene knockdown approach in glioma cells. Its protein expression by immunohistochemistry (IHC) was correlated with other clinically relevant GBM markers, patient prognosis and tumor recurrence.

RESULTS

The mRNA expression of selected genes from the microarray data validated in tumor core and PBZ and was similar to publicly available databases. SERPINA3 knock down in vitro showed decreased tumor cell proliferation, invasion, migration, transition to mesenchymal phenotype, stemness and radioresistance. SERPINA3 protein expression was higher in PBZ compared to tumor core and also was higher in older patients, IDH wild type and recurrent tumors. Finally, its expression showed positive correlation with poor patient prognosis.

CONCLUSIONS

SERPINA3 expression contributes to aggressive GBM phenotype by regulating pro-tumorigenic actions in vitro and is associated with adverse clinical outcome.

CKS2 modulates cell-cycle progression of tongue squamous cell carcinoma cells partly via modulating the cellular distribution of DUTPase

BACKGROUND

CKS2 (CDC28 Protein Kinase Regulatory Subunit 2) is a gene that encodes CKS2 protein that has been characterized as a binding partner of the catalytic subunit of the cyclin-dependent kinases. However, its expression profile and regulatory effects in tongue squamous cell carcinoma has not yet been explored.

METHODS

Bioinformatic analysis was conducted using bulk-seq data from The Cancer Genome Atlas and single-cell RNA-seq data from GSE103322. SCC9 and CAL27 cells were used as in vitro cell models for cellular and molecular studies.

RESULTS

CKS2 expression was significantly upregulated in tongue squamous cell carcinoma tissues (N = 128) compared with adjacent normal tissues (N = 13). Its upregulation was associated with significantly shorter disease-specific survival and progression-free survival. Cellular status estimation in tumor cells indicated that CKS2 expression was moderately and positively correlated with cell-cycle progression. CKS2 inhibition in SCC9 and CAL27 cells resulted in decreased proliferation, weakened colony formation capability, and cell-cycle arrest at the G2/M phase. Immunofluorescence staining and co-Immunoprecipitation (co-IP) assay confirmed co-localization and interaction between CKS2 and DUTPase. CKS2 knockdown did not alter DUTPase expression but reduced its nuclear distribution. Both CKS2 and DUT expression were moderately correlated with their gene-level copy number.

CONCLUSION

CKS2 expression is associated with unfavorable survival of patients with tongue squamous cell carcinoma. Inhibiting its expression could reduce tongue squamous cell carcinoma cell growth and induce G2/M arrest. CKS2 may interact with DUTPase and regulate its nuclear localization. Gene-level copy amplification might be an important mechanism of upregulated CKS2 and DUT in the tumor.

Molecular comparison of pure ovarian fibroma with serous benign ovarian tumours

OBJECTIVE

Ovarian fibromas and adenofibromas are rare ovarian tumours. They are benign tumours composed of spindle-like stromal cells (pure fibroma) or a mixture of fibroblast and epithelial components (adenofibroma). We have previously shown that 40% of benign serous ovarian tumours are likely primary fibromas due to the neoplastic alterations being restricted to the stromal compartment of these tumours. We further explore this finding by comparing benign serous tumours to pure fibromas.

RESULTS

Performing copy number aberration (CNA) analysis on the stromal component of 45 benign serous tumours and 8 pure fibromas, we have again shown that trisomy of chromosome 12 is the most common aberration in ovarian fibromas. CNAs were more frequent in the pure fibromas than the benign serous tumours (88% vs 33%), however pure fibromas more frequently harboured more than one CNA event compared with benign serous tumours. As these extra CNA events observed in the pure fibromas were unique to this subset our data indicates a unique tumour evolution. Gene expression analysis on the two cohorts was unable to show gene expression changes that differed based on tumour subtype. Exome analysis did not reveal any recurrently mutated genes.

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.

Overexpression of CKS2 is associated with a poor prognosis and promotes cell proliferation and invasion in breast cancer

Growing evidence indicates that cyclin dependent kinases regulatory subunit 2 (CKS2) serves an essential role in the regulation of multiple cellular processes in diverse human cancer types. The present study investigated the contribution of CKS2 to breast cancer (BC) progression. In the present study, CKS2 expression in BC was detected using Oncomine and The Cancer Genome Atlas database. The association between expression levels and clinical features was explored using Kaplan‑Meier plotter and the Breast Cancer Gene‑Expression Miner Version 4.0 (bc‑GenExMiner) online database. In addition, the roles of CKS2 in BC progression were examined. It was identified that CKS2 expression was significantly increased in BC tissues at the mRNA and protein levels. Bc‑GenExMiner demonstrated that high CKS2 expression was associated with a positive estrogen receptor status, progesterone receptor status, nodal status and basal‑like status. High CKS2 expression was markedly associated with poor overall survival, relapse‑free survival, and distant metastasis‑free survival in patients with BC. Moreover, functional assays revealed that CKS2 inhibition suppressed cell proliferation and invasion ability in vitro and reduced tumor growth in vivo. Thus, the present findings suggested that CKS2 may act as a potential biomarker and therapeutic target for the treatment of BC.

Integrative analysis of gene expression profiles reveals specific signaling pathways associated with pancreatic duct adenocarcinoma

Background

Pancreatic duct adenocarcinoma (PDAC) remains a major health problem because conventional cancer treatments are relatively ineffective against it. Microarray studies have linked many genes to pancreatic cancer, but the available data have not been extensively mined for potential insights into PDAC. This study attempted to identify PDAC-associated genes and signaling pathways based on six microarray-based profiles of gene expression in pancreatic cancer deposited in the gene expression omnibus database.

Methods

Pathway network methods were used to analyze core pathways in six publicly available pancreatic cancer gene (GSE71989, GSE15471, GSE16515, GSE32676, GSE41368 and GSE28735) expression profiles. Genes potentially linked to PDAC were assessed for potential impact on survival time based on data in The Cancer Genome Atlas and International Cancer Genome Consortium databases, and the expression of one candidate gene (CKS2) and its association with survival was examined in 102 patients with PDAC from our hospital. Effects of CKS2 knockdown were explored in the PDAC cell lines BxPC-3 and CFPAC-1.

Results

The KEGG signaling pathway called “pathway in cancer” may play an important role in pancreatic cancer development and progression. Five genes (BIRC5, CKS2, ITGA3, ITGA6 and RALA) in this pathway were significantly associated with survival time in patients with PDAC. CKS2 was overexpressed in PDAC samples from our hospital, and higher CKS2 expression in these patients was associated with shorter survival time. CKS2 knockdown substantially inhibited PDAC cell proliferation in vitro.

Conclusions

Analysis integrating existing microarray datasets allowed identification of the “pathway in cancer” as an important signaling pathway in PDAC. This integrative approach may be powerful for identifying genes and pathways involved in cancer.

Electronic supplementary material

The online version of this article (10.1186/s40880-018-0289-9) contains supplementary material, which is available to authorized users.

The Cks1/Cks2 axis fine-tunes Mll1 expression and is crucial for MLL-rearranged leukaemia cell viability

The Cdc28 protein kinase subunits, Cks1 and Cks2, play dual roles in Cdk-substrate specificity and Cdk-independent protein degradation, in concert with the E3 ubiquitin ligase complexes SCFSkp2 and APCCdc20. Notable targets controlled by Cks include p27 and Cyclin A. Here, we demonstrate that Cks1 and Cks2 proteins interact with both the MllN and MllC subunits of Mll1 (Mixed-lineage leukaemia 1), and together, the Cks proteins define Mll1 levels throughout the cell cycle. Overexpression of CKS1B and CKS2 is observed in multiple human cancers, including various MLL-rearranged (MLLr) AML subtypes. To explore the importance of MLL-Fusion Protein regulation by CKS1/2, we used small molecule inhibitors (MLN4924 and C1) to modulate their protein degradation functions. These inhibitors specifically reduced the proliferation of MLLr cell lines compared to primary controls. Altogether, this study uncovers a novel regulatory pathway for MLL1, which may open a new therapeutic approach to MLLr leukaemia.

Apoptosis-related protein-1 acts as a tumor suppressor in cholangiocarcinoma cells by inducing cell cycle arrest via downregulation of cyclin-dependent kinase subunits

Cholangiocarcinoma, a malignancy arising from the biliary tract, is associated with high mortality due to the late diagnosis and lack of effective therapeutic approaches. Our knowledge of the molecular alterations during the carcinogenesis of cholangiocarcinoma is limited. Previous study suggests that apoptosis-related protein-1 (Apr-1) is involved in cancer cell proliferation and survival. In the present study, we first detected the expression pattern of Apr-1 in human cholangiocarcinoma tissues and the effects of forced Apr-1 expression on cell proliferation and cell cycle progression. Cell cycle gene array analysis was used to identify downstream molecules that were regulated by Apr-1, and their expression levels were further evaluated in human cholangiocarcinoma tissues. We showed that Apr-1 expression was downregulated in human cholangiocarcinoma tissues. Forced expression of Apr-1 inhibited cell proliferation of cholangiocarcinoma cell line QBC939 and induced G2/M phase arrest. Downregulation of cell cycle-related genes cyclin-dependent kinase (Cdk) 2, and cyclin-dependent kinase subunits (Cks) 1 and 2 was involved in Apr-1-induced cell cycle arrest. Furthermore, we found that Cdk2 and Cks1/2 expression levels were elevated in human cholangiocarcinoma tissues. Taken together, our data showed that Apr-1 plays a crucial role in cell proliferation by controlling cell cycle progression, implying a tumor-suppressor function of Apr-1 in cholangiocarcinoma carcinogenesis. Thus, the present study provides a rationale to further study the underlying mechanisms of Apr-1 downregulation in cholangiocarcinoma for exploring potential diagnostic and therapeutic targets.

CKS2 in human cancers: Clinical roles and current perspectives (Review)

Cyclin-dependent kinase subunit 2 (CKS2) is indicated in the processes of cell cycle and cell proliferation. Through these processes, CKS2 is identified as a cancer gene, but its role has not been well reviewed. The aim of the present study was to summarize the clinicopathological significance and the molecular mechanisms of CKS2 in human cancers. Its expression was upregulated in the majority of the types of cancer studied. CKS2 was shown to have a function in cancers of the digestive tract, genital tract, thyroid, nerve and certain other types of cancer. CKS2 can promote progression of certain cancers via positive control of proliferation, invasion and migration. Downregulation of CKS2 induces cancer cell apoptosis. CKS2 can change a multitude of cellular mechanisms in cancer pathogenesis by regulating the gene translation of numerous validated targets, such as p53, CDK1, cyclin A, cyclin B1, caspase-3 and Bax. In addition, the molecular mechanism that causes aberrant expression of CKS2 was epigenetic modification of miR-26a and the Y-box-binding protein 1 (YB-1) gene. In conclusion, CKS2 is commonly elevated in cancer, most likely due to its ability to promote cancer cell growth, invasion and migration through regulating certain significant genes. Understanding the mechanisms by which CKS2 is involved with cancer pathogenesis will be useful in the development of tumor therapy for patients with cancer.

Microarray analysis of cell cycle gene expression in adult human corneal endothelial cells

Corneal endothelial cells (ECs) form a monolayer that controls the hydration of the cornea and thus its transparency. Their almost nil proliferative status in humans is responsible, in several frequent diseases, for cell pool attrition that leads to irreversible corneal clouding. To screen for candidate genes involved in cell cycle arrest, we studied human ECs subjected to various environments thought to induce different proliferative profiles compared to ECs in vivo. Donor corneas (a few hours after death), organ-cultured (OC) corneas, in vitro confluent and non-confluent primary cultures, and an immortalized EC line were compared to healthy ECs retrieved in the first minutes of corneal grafts. Transcriptional profiles were compared using a cDNA array of 112 key genes of the cell cycle and analysed using Gene Ontology classification; cluster analysis and gene map presentation of the cell cycle regulation pathway were performed by GenMAPP. Results were validated using qRT-PCR on 11 selected genes. We found several transcripts of proteins implicated in cell cycle arrest and not previously reported in human ECs. Early G1-phase arrest effectors and multiple DNA damage-induced cell cycle arrest-associated transcripts were found in vivo and over-represented in OC and in vitro ECs. Though highly proliferative, immortalized ECs also exhibited overexpression of transcripts implicated in cell cycle arrest. These new effectors likely explain the stress-induced premature senescence that characterizes human adult ECs. They are potential targets for triggering and controlling EC proliferation with a view to increasing the cell pool of stored corneas or facilitating mass EC culture for bioengineered endothelial grafts.

Overexpression of CDC28 protein kinase regulatory subunit 1B confers an independent prognostic factor in nasopharyngeal carcinoma

Data mining on public domain identified that CDC28 protein kinase regulatory subunit 1B (CKS1B) transcript was highly expressed in nasopharyngeal carcinoma (NPC). The expression of CKS1B protein and its clinicopathological associations in patients with NPC were further evaluated. Immunoexpression of CKS1B was retrospectively assessed in biopsies of 124 consecutive NPC patients without initial distant metastasis and treated with consistent guidelines. The correlations between CKS1B immunoexpression levels and clinicopathological features, as well as patient survivals, were analyzed. High CKS1B expression (49.2%) was correlated with the 7th American Joint Committee on Cancer (AJCC) stage (p = 0.014). In multivariate analyses, high CKS1B expression emerged as an independent prognostic factor for worse disease-specific survival (p < 0.001), metastasis-free survival (p < 0.001), and local recurrence-free survival (p = 0.001). High expression of CKS1B is common and associated with adverse prognostic factors and might confer tumor aggressiveness through dysregulation of the cyclin-dependent protein kinase (intrinsic regulatory activity) during cell cycle progression.

Expression and clinical significance of cyclin kinase subunit 2 in colorectal cancer

The overexpression of cyclin kinase subunit 2 (CKS2) is tightly correlated with tumor aggressiveness and prognosis in various malignancies, including gastric, breast, liver and prostate cancer. However, whether CKS2 is upregulated in colorectal cancer (CRC) remains unknown. The aim of the present study was to analyze CKS2 expression levels in CRC, and to determine the clinical diagnostic and prognostic values of CKS2 overexpression in CRC patients. CKS2 expression was analyzed at the mRNA and protein levels by quantitative (q)PCR and western blot analysis. CKS2 expression was significantly upregulated in CRC compared with the adjacent non-cancer and normal colorectal tissues. The overexpression of CKS2 was correlated with poor differentiation and the pathological stage. In addition, CKS2 overexpression was correlated with aggressive tumor progression in CRC, which indicated that CKS2 may serve as a good CRC biomarker.

Oncogenic potential of cyclin kinase subunit-2 in cholangiocarcinoma

BACKGROUND

Cyclin kinase subunit-2 (Cks2), a member of the human Cks family, plays an important role in the regulation of meiosis and mitosis; and its abnormal expression is usually associated with carcinogenesis. However, its exact functions and molecular mechanisms remain unclear.

AIMS

To observe Cks2 expression in cholangiocarcinoma and explore its role in the carcinogenesis of cholangiocarcinoma and possible mechanism.

METHODS

Cks2 expression in cholangiocarcinoma was detected with immunostaining and RT-PCR. MTT, colony formation, immunofluorescence, flow cytometry and Western blotting were performed to explore the role of Cks2 in cholangiocarcinoma and possible mechanism.

RESULTS

Cks2 was significantly elevated in cholangiocarcinoma tissues and its over-expression was associated with poor differentiation, CA19-9 and poor prognosis. Furthermore, Cks2 down-regulation inhibited cholangiocarcinoma cell proliferation and colony formation in vitro, and the growth of cholangiocarcinoma xenografts in animals; especially, enhanced the sensitivity of cholangiocarcinoma cells to chemotherapy. We further found that Cks2 knockdown induced cholangiocarcinoma cell cycle arrest in G2/M phase through down-regulation of Cyclin A and Cyclin B1 and Bax up-regulation and activation, mitochondrial membrane permeabilization and caspase-3 activation, which resulted in facilitating cholangiocarcinoma apoptosis.

CONCLUSIONS

These findings suggest that Cks2 may serve as an independent prognostic factor in patients with cholangiocarcinoma, and play an important role in the carcinogenesis of cholangiocarcinoma by facilitating cell cycle progression and Bax-mediated mitochondrial caspase-dependent apoptosis.

Clinical significance of overexpressed cyclin-dependent kinase subunits 1 and 2 in esophageal carcinoma

The mammalian cyclin-dependent kinase subunit (Cks) family has two members, Cks1 and Cks2. Overexpression of Cks1 and Cks2 has been reported to be associated with high aggressiveness and poor prognosis in several malignancies, including prostate and hepatocellular carcinomas. However, whether Cks1 and Cks2 are overexpressed in esophageal carcinoma remains uncharacterized. To investigate whether overexpression of the Cks family is clinically relevant in esophageal carcinoma, and whether expression patterns of Cks1 and Cks2 can serve as biomarkers for esophageal carcinoma. Real-time quantitative reverse transcription polymerase chain reaction, immunohistochemistry, and Western blot analyses were applied to detect the expression of Cks1 and Cks2 at the mRNA and protein levels, respectively. The associations between Cks1 or Cks2 expressions and clinical features and p27(kip1) expressions in esophageal carcinoma were analyzed. Comparing with the adjacent noncancerous tissues, esophageal carcinoma exhibited elevated expression of Cks1 in 58% cases at the mRNA level and 54% cases at the protein level, and elevated expression of Cks2 in 65% cases at the mRNA level and 61% cases at the protein level, respectively. The expressions of both Cks1 and Cks2 were negatively associated with the p27(kip1) protein level in the tumor tissues. Furthermore, overexpression of Cks1 and Cks2 in esophageal carcinoma was closely associated with poor pathological features of esophageal carcinoma, including higher histologic grade of tumor, regional lymph nodes invasion, and neoplastic embolus. Overexpression of Cks1 and Cks2 is associated with the aggressive tumor behaviors of esophageal carcinoma. Further efforts are needed to determine whether overexpression of Cks1 and Cks2 can serve as novel biomarkers for esophageal carcinoma.

Genetic alterations associated with progression and recurrence in meningiomas

Meningiomas are the most common primary brain tumors; they arise from the coverings of the brain. Although meningiomas are generally benign, some are more clinically aggressive, as reflected by their histopathological features or by their unexpected recurrence. We hypothesized that recurrent histologically benign meningiomas might have genetic features in common with those showing a more aggressive histology. By comparing gene expression profiles associated with meningioma progression and recurrence in 128 tumor samples (i.e. 83 benign World Health Organization [WHO] Grade I, 37 atypical WHO Grade II, and 8 anaplastic WHO Grade III) from 121 patients, we identified a 49-gene signature of meningioma aggressivity. This signature classified the tumors into 2 groups showing different clinical and pathological behaviors. The signature was composed of genes involved in the cell cycle (TMEM30B, CKS2, and UCHL1) and other pathways previously described as being altered in meningiomas, that is, WNT (SFRP1 and SFRP4) and transforming growth factor-β pathways (LTBP2 and LMO4). Overall, gene downregulation was observed in advanced and recurrent samples versus benign and original ones. We propose that this gene repression may be caused by gene promoter hypermethylation, as in the case of UCHL1 and SFRP1, suggesting that this epigenetic event, together with loss of specific chromosomal regions, may play an important role in meningioma progression and recurrence.

Refinement of 1p36 alterations not involving PRDM16 in myeloid and lymphoid malignancies

Fluorescence in situ hybridization was performed to characterize 81 cases of myeloid and lymphoid malignancies with cytogenetic 1p36 alterations not affecting the PRDM16 locus. In total, three subgroups were identified: balanced translocations (N = 27) and telomeric rearrangements (N = 15), both mainly observed in myeloid disorders; and unbalanced non-telomeric rearrangements (N = 39), mainly observed in lymphoid proliferations and frequently associated with a highly complex karyotype. The 1p36 rearrangement was isolated in 12 cases, mainly myeloid disorders. The breakpoints on 1p36 were more widely distributed than previously reported, but with identifiable rare breakpoint cluster regions, such as the TP73 locus. We also found novel partner loci on 1p36 for the known multi-partner genes HMGA2 and RUNX1. We precised the common terminal 1p36 deletion, which has been suggested to have an adverse prognosis, in B-cell lymphomas [follicular lymphomas and diffuse large B-cell lymphomas with t(14;18)(q32;q21) as well as follicular lymphomas without t(14;18)]. Intrachromosomal telomeric repetitive sequences were detected in at least half the cases of telomeric rearrangements. It is unclear how the latter rearrangements occurred and whether they represent oncogenic events or result from chromosomal instability during oncogenesis.

DNA microarray analysis identifies CKS2 and LEPR as potential markers of meningioma recurrence

Meningiomas are the most frequent intracranial tumors. Surgery can be curative, but recurrences are possible. We performed gene expression analyses and loss of heterozygosity (LOH) studies looking for new markers predicting the recurrence risk. We analyzed expression profiles of 23 meningiomas (10 grade I, 10 grade II, and 3 grade III) and validated the data using quantitative polymerase chain reaction (qPCR). We performed LOH analysis on 40 meningiomas, investigating chromosomal regions on 1p, 9p, 10q, 14q, and 22q. We found 233 and 268 probe sets to be significantly down- and upregulated, respectively, in grade II or III meningiomas. Genes downregulated in high-grade meningiomas were overrepresented on chromosomes 1, 6, 9, 10, and 14. Based on functional enrichment analysis, we selected LIM domain and actin binding 1 (LIMA1), tissue inhibitor of metalloproteinases 3 (TIMP3), cyclin-dependent kinases regulatory subunit 2 (CKS2), leptin receptor (LEPR), and baculoviral inhibitor of apoptosis repeat-containing 5 (BIRC5) for validation using qPCR and confirmed their differential expression in the two groups of tumors. We calculated ΔCt values of CKS2 and LEPR and found that their differential expression (C-L index) was significantly higher in grade I than in grade II or III meningiomas (p < .0001). Interestingly, the C-L index of nine grade I meningiomas from patients who relapsed in <5 years was significantly lower than in grade I meningiomas from patients who did not relapse. These findings indicate that the C-L index may be relevant to define the progression risk in meningioma patients, helping guide their clinical management. A prospective analysis on a larger number of cases is warranted.

Significance of expression of AKT, p27Kip1 and cyclin E in gastric carcinoma

AIM: To investigate the expression of AKT, p27^Kip1 and cyclin E proteins in gastric carcinoma and to explore their significance in tumor development and progression.

METHODS: Biopsy and surgical specimens were collected in the Xiangtan City First People's Hospital and Affiliated Nanhua Hospital of University of South China from January 2008 to January 2010, including 14 cases of normal gastric mucosa, 10 cases of atypical hyperplasia, 94 cases of gastric cancer, 49 cases of cancer-adjacent tissue and 35 cases of metastatic cancer. Tissue array technology was used to detect the phosphorylation of AKT and p27^Kip1 proteins and the expression of cyclin E by immunohistochemistry.

RESULTS: Compared to normal gastric mucosa, cancer-adjacent tissue and atypical hyperplasia, the positive rates of AKT phosphorylation and cyclin E overexpression were significantly higher (AKT: 85.1%, 85.7% vs 14.3%, 26.5%, 30.0%; Cyclin E: 85.1%, 82.9% vs 14.3%, 34.7%, 20.0%, all P < 0.01) and that of p27^Kip1 phosphorylation was significantly lower (22.3%, 17.1% vs 71.4%, 44.9%, 40.0%, all P < 0.01) in primary cancer and metastatic carcinoma. Compared to normal gastric mucosa, the positive rate of AKT phosphorylation was significantly higher in atypical hyperplasia (P = 0.26).

CONCLUSION: The phosphorylation of AKT and p27^Kip1 and expression of cyclin E protein are possibly related to the development and progression of gastric carcinoma.

Expression and biological-clinical significance of hTR, hTERT and CKS2 in washing fluids of patients with bladder cancer

BACKGROUND

at present, pathogenesis of bladder cancer (BC) has not been fully elucidated. Aim of this study is to investigate the role of human telomerase RNA (hTR), human telomerase reverse transcriptase (hTERT) and CDC28 protein kinase regulatory subunit 2 (CKS2) in bladder carcinogenesis and their possible clinical significance;

METHODS

the transcript levels of hTR, hTERT and CKS2 were quantified by Real time reverse transcriptase chain reaction in exfoliated cells from bladder washings of 36 patients with BC and 58 controls. The statistical significance of differences between BC bearing patients and control groups, in the general as well as in the stratified analysis (superficial or invasive BC), was assessed by Student's t test. Non parametric Receiver Operating Characteristics analysis (ROC) was performed to ascertain the accuracy of study variables to discriminate between BC and controls. The clinical value of concomitant examination of hTR, hTERT and CKS2 was evaluated by logistic regression analysis;

RESULTS

a significant decrease in hTR and a significant increase in hTERT or CKS2 gene expression were found between BC bearing patients and controls, as well as in the subgroups analysis. The area under the curve (AUC) indicated an average discrimination power for the three genes, both in the general and subgroups analysis, when singularly considered. The ability to significantly discriminate between superficial and invasive BC was observed only for hTR transcript levels. A combined model including hTR and CKS2 was the best one in BC diagnosis;

CONCLUSIONS

our results, obtained from a sample set particularly rich of exfoliated cells, provide further molecular evidence on the involvement of hTR, hTERT and CKS2 gene expression in BC carcinogenesis. In particular, while hTERT and CKS2 gene expression seems to have a major involvement in the early stages of the disease, hTR gene expression, seems to be more involved in progression. In addition, our findings suggest that the studied genes have a clinical role in discriminating between BC and controls in the general as well as in the stratified analysis, when singularly considered. A combined model improved over the single marker BC diagnosis.

Clinical significance and expression of cyclin kinase subunits 1 and 2 in hepatocellular carcinoma

BACKGROUND

The mammalian cyclin kinase subunit (Cks) family has two members, Cks1 and Cks2, which were identified based on the protein sequence homology to yeast Cks. Overexpression of Cks1 and Cks2 has been reported to be associated with high aggressiveness and a poor prognosis in various malignancies, including gastric, breast and prostate carcinomas. Yet, whether Cks1 and Cks2 are overexpressed in hepatocellular carcinoma (HCC) remains uncharacterized.

AIMS

To investigate whether overexpression of the Cks family is clinically relevant to HCC, and whether expression patterns of Cks1 and Cks2 in HCC have diagnostic and prognostic value.

METHODS

Real-time quantitative reverse transcriptase polymerase chain reaction, immunostaining and Western blot analyses were used to detect the expression of Cks1 and Cks2 at the mRNA and protein levels respectively. The associations between Cks1 and Cks2 expressions and clinical features, as well as the association between Cks1 or Cks2 and p27(kip1) expressions in HCC, were analysed.

RESULTS

Expressions of Cks1 and Cks2 at both mRNA and protein levels were significantly higher in HCC than those in the adjacent noncancerous tissues (including chronic hepatitis and cirrhosis) and normal liver tissues. Overexpressions of Cks1 and Cks2 in HCC were closely associated with poor differentiation features. The expressions of both Cks1 and Cks2 were negatively associated with p27(kip1) at the protein level.

CONCLUSIONS

Overexpression of Cks1 and Cks2 is associated with the aggressive tumour behaviours of HCC, and thus has diagnostic and prognostic value. Further efforts are needed to develop novel biomarkers for HCC based on CKs1 and Cks2 expressions.