Upregulated PFTK1 promotes tumor cell proliferation, migration, and invasion in breast cancer

Cyclin-dependent kinases: Masters of the eukaryotic universe

A family of structurally related cyclin-dependent protein kinases (CDKs) drives many aspects of eukaryotic cell function. Much of the literature in this area has considered individual members of this family to act primarily either as regulators of the cell cycle, the context in which CDKs were first discovered, or as regulators of transcription. Until recently, CDK7 was the only clear example of a CDK that functions in both processes. However, new data points to several "cell-cycle" CDKs having important roles in transcription and some "transcriptional" CDKs having cell cycle-related targets. For example, novel functions in transcription have been demonstrated for the archetypal cell cycle regulator CDK1. The increasing evidence of the overlap between these two CDK types suggests that they might play a critical role in coordinating the two processes. Here we review the canonical functions of cell-cycle and transcriptional CDKs, and provide an update on how these kinases collaborate to perform important cellular functions. We also provide a brief overview of how dysregulation of CDKs contributes to carcinogenesis, and possible treatment avenues. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Processing > 3' End Processing RNA Processing > Splicing Regulation/Alternative Splicing.

CDK14 inhibition reduces mammary stem cell activity and suppresses triple negative breast cancer progression

The Wnt/β-catenin signaling pathway plays an important role in regulating mammary organogenesis and oncogenesis. However, therapeutic methods targeting the Wnt pathway against breast cancer have been limited. To address this challenge, we investigate the function of cyclin-dependent kinase 14 (CDK14), a member of the Wnt signaling pathway, in mammary development and breast cancer progression. We show that CDK14 is expressed in the mammary basal layer and elevated in triple negative breast cancer (TNBC). CDK14 knockdown reduces the colony-formation ability and regeneration capacity of mammary basal cells and inhibits the progression of murine MMTV-Wnt-1 basal-like mammary tumor. CDK14 knockdown or pharmacological inhibition by FMF-04-159-2 suppresses the progression and metastasis of TNBC. Mechanistically, CDK14 inhibition inhibits mammary regeneration and TNBC progression by attenuating Wnt/β-catenin signaling. These findings highlight the significance of CDK14 in mammary development and TNBC progression, shedding light on CDK14 as a promising therapeutic target for TNBC.

CDK14/β-catenin/TCF4/miR-26b positive feedback regulation modulating pancreatic cancer cell phenotypes in vitro and tumor growth in mice model in vivo

INTRODUCTION

Chemotherapy and radiotherapy have been reported to be basically ineffective for pancreatic ductal adenocarcinoma patients; thus, gene therapy might provide a novel approach. CDK14, a new oncogenic member of the CDK family involved in the pancreatic cancer cell response to gemcitabine treatment, has been reported to be regulated by microRNAs. In the present study, we aimed to investigate whether miR-26b regulated CDK14 expression to affect the phenotype of pancreatic cancer cells.

METHODS

Overexpression or knockdown of CDK14 or miR-26b was generated in pancreatic cancer cell lines and the function of CDK14 and miR-26b on cell phenotype and the Wnt signaling pathway was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-ethynyl-2'-deoxyuridine and transwell assays, as well as a xenograft model and western blotting. The predicted binding site between the 3'-untranslated region of CDK14 and miR-26b, miR-26b promoter and TCF4 was verified by luciferase or chromatin immunoprecipitation assays.

RESULTS

CDK14 overexpression inhibited p-GSK3β, whereas it promoted p-LRP6, the nuclear translocation of β-catenin and the transactivation of TCF4 transcription factor, thus promoting pancreatic cancer cell aggressiveness. miR-26b directly targeted CDK14 and inhibited CDK14 expression. In vitro and in vivo, miR-26b overexpression inhibited, and CDK14 overexpression promoted, cancer cell aggressiveness; CDK14 overexpression partially attenuated the miR-26b overexpression effects on cancer cells. The effects of miR-26b overexpression on tumor growth and the Wnt/β-catenin/TCF4 signaling were partially reversed by CDK14 overexpression. TCF4 inhibited the expression of miR-26b by targeting its promoter region.

CONCLUSIONS

CDK14, β-catenin, TCF4 and miR-26b form a positive feedback regulation for modulating pancreatic cancer cell phenotypes in vitro and tumor growth in vivo.

The Candidate IBD Risk Gene CCNY Is Dispensable for Intestinal Epithelial Homeostasis

The CCNY gene, which encodes cyclin Y, has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Cyclin Y promotes Wnt/β-catenin signaling and autophagy, which are critical for intestinal epithelial cell (IEC) homeostasis, and may thereby contribute to wound repair in colitis. However, whether cyclin Y has an essential function in IECs is unknown. We, therefore, investigated the epithelial injury response and mucosal regeneration in mice with conditional knock-out of Ccny in the intestinal epithelium. We observed that Ccny-deficient mice did not exhibit any differences in cell proliferation and disease activity compared to wild-type littermates in the dextran sulfate sodium (DSS) colitis model. Complementary in vitro experiments showed that loss of CCNY in model IECs did not affect Wnt signaling, cell proliferation, or autophagy. Additionally, we observed that expression of the cyclin-Y-associated cyclin-dependent kinase (CDK) 14 is exceedingly low specifically in IEC. Collectively, these results suggest that cyclin Y does not contribute to intestinal epithelial homeostasis, possibly due to low levels of specific CDKs in these cells. Thus, it is unlikely that CCNY mutations are causatively involved in IBD pathogenesis.

Hsa_circRNA_102229 facilitates the progression of triple-negative breast cancer via regulating the miR-152-3p/PFTK1 pathway

Background

Increasing evidence has suggested that circular RNAs (circRNAs) may act as an important regulatory factor in tumor progression. However, how circRNAs exert their functions in triple‐negative breast cancer (TNBC) remains not clearly understood.

Methods

First, circRNA microarrays were conducted to identify aberrantly expressed circRNAs in TNBC tissues. Kaplan–Meier survival analysis was conducted to calculate the correlation between the level of hsa_circRNA_102229 and outcomes of patients with TNBC. The effect of hsa_circRNA_102229 and serine/threonine‐protein kinase PFTAIRE 1 (PFTK1) on TNBC cells was clarified by cell counting kit‐8, transwell and wound healing assays, as well as by a flow cytometry. The molecular mechanism of hsa_circRNA_102229 was clarified through bioinformatics, a dual‐luciferase reporter assay, western blotting, fluorescence in situ hybridization and real‐time polymerase chain reaction. Tumor xenograft experiments were performed to analyze growth and metastasis of TNBC in vivo.

Results

In TNBC tissues and cells, hsa_circ_102229 was remarkably up‐regulated. Patients with TNBC presenting high hsa_circ_102229 exhibited poor prognosis. Moreover, hsa_circ_102229 could promote the migration, proliferation and invasion, whereas it inhibited the apoptosis of TNBC cells. Furthermore, hsa_circ_102229 directly targeted miR‐152‐3p and could regulate the expression of PFTK1 by targeting miR‐152‐3p. Rescue assays suggested that hsa_circ_102229 may exert its function in TNBC cells by regulating PFTK1. Additionally, knockdown of hsa_circ_102229 slowed down TNBC tumorigenesis and lung metastasis in a tumor xenograft animal model.

Conclusions

Hsa_circ_102229 might serve as a competing endogenous RNA (ceRNA) to modulate PFTK1 expression via regulating miR‐152‐3p to affect the functions of TNBC cells. Hsa_circ_102229 acts as a newly discovered biomarker for TNBC treatment.

The anti-tumor effect of miR-539-3p on colon cancer via regulating cell viability, motility, and nude mouse tumorigenicity with CDK14 inhibition

BACKGROUND

Colon cancer is one of the major causes of morbidity and mortality worldwide. MicroRNAs (miRNAs) play important functions in the growth and metastasis of colon cancer. This study aimed to investigate the anti-tumor effect of micro ribonucleic acid 539-3p (miR-539-3p) on colon cancer via regulation of cell viability, motility, and nude mouse tumorigenicity with cyclin-dependent kinase 14 (CDK14) inhibition.

METHODS

The target relationship between miR-539-3p and CDK14 was predicted using TargetScan software, and were detected by luciferase reporter assay. Cell counting kit-8 (CCK-8) assay and flow cytometry were employed to examine cell proliferation and apoptosis. Western blotting was employed to measure the protein expression levels of p27, cleaved caspase-3, and epithelial (E)- and neural (N)-cadherin. The effect of miR-539-3p on tumor growth was evaluated by establishing a xenograft tumor model in nude mice.

RESULTS

The target relationship of CDK14 and miR-539-3p was identified as a negative regulator. Overexpression of miR-539-3p significantly inhibited SW620 and SW480 cell proliferation, promoted cell apoptosis, and suppressed cell invasion by targeting CDK14. The xenograft tumor model showed that the overexpression of miR-539-3p reduced tumor weight and volume. Immunohistochemical staining revealed that the overexpression of miR-539-3p inhibited the expression of Ki67 and E-cadherin. Additionally, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining showed that overexpression of miR-539-3p induced apoptosis.

CONCLUSIONS

Overexpression of miR-539-3p inhibited SW620 and SW480 cell proliferation, promoted cell apoptosis, and suppressed cell invasion by targeting CDK14. Therefore, miR-539-3p may be a useful diagnostic and therapeutic biomarker for colon cancer.

Downregulation of PFTK1 Inhibits Migration and Invasion of Non-Small Cell Lung Cancer

Background

PFTK1, a novel cyclin-dependent kinase, plays pivotal roles in tumorigenesis. Cell motility and invasiveness could be enhanced by PFTK1 in various tumors. However, the function of PFTK1 in NSCLC metastasis remains unclear. In this study, the potential role of PFTK1 in NSCLC metastasis was determined.

Materials and Methods

In this study, the potential function of PFTK1 in lung cancer patients was analyzed with the Kaplan–Meier plotter database. RNA interference-mediated knockdown of PFTK1 was established in two NSCLC cell lines (H1299 and 95C) to explore the role of PFTK1 in NSCLC. The efficacy of downregulation of PFTK1 was examined by Western blot and immunofluorescence. The role of PFTK1 in cell migration and invasion ability was detected by wound healing and transwell assays. The protein levels in lung cancer cells were determined by Western blot. Immunofluorescence analysis was used to evaluate the structure of filamentous actin.

Results

Overexpression of PFTK1 was associated with the poor survival prognosis in NSCLC patients. PFTK1 knockdown cells were constructed successfully. Suppression of PFTK1 significantly inhibited the cell migration and invasion in H1299 and 95C cells. Notably, after PFTK1 downregulation, the epithelial–mesenchymal transition (EMT) markers vimentin, ZEB1 and β-catenin were obviously decreased. Additionally, immunofluorescence analysis indicated that PFTK1 downregulation remarkably induced filamentous actin depolymerization.

Conclusion

In summary, PFTK1 could significantly promote lung cancer metastasis through changing EMT progress and modulating intracellular cytoskeleton F-actin expression. Taken together, our findings indicated that PFTK1 might serve as a novel therapeutic target for the inhibition of NSCLC progression.

CDK14 involvement in proliferation migration and invasion of esophageal cancer

Background

CDK14 has significant involvement in tumorigenesis of cancers including hepatocellular carcinoma, gastric carcinoma and breast cancer. In esophageal cancer, CDK14 is useful as a prognostic marker and as a predictor of response to chemotherapy. However, the exact mechanism of CDK14 n chemotherapy for esophageal squamous cell carcinoma (ESCC) has not been explored.

Methods

Western blots and immunohistochemistry (IHC) analysis were performed to analyse the expression of CDK14 in ESCC. Co-immunoprecipitation and immunofluorescence assays were used to explore the mechanism of CDK14 involvement in ESCC. Colony formation assays and proliferation assays were used to investigate the function of CDK14 in ESCC. At last, we constructed two truncated mutants of CDK14 by the PCR technology to research the functional structural domain.

Results

Western blots and IHC analysis showed that CDK14 expression was higher n tumor tissues and cell lines than that in normal tissues. IHC staining revealed that CDK14 positively correlated with clinical pathological variables of tumor size (P=0.001), tumor grade (P=0.004), Ki-67 (P=0.012) and survival (P=0.000). Immunoprecipitation and immunofluorescence assays revealed that CDK-activating kinase (CAK), namely CDK7/CCNH complex physically interacted and was collocated with CDK14 in the cell nucleus. This direct interaction increased CDK14 phosphorylation and inhibited Rb function through phosphorylation. In vitro starvation and refeeding assays demonstrated that CDK14 expression was related to proliferation of ESCC cells. Overexpression of CDK14 in Eca109 cells increased colony formation and reduced sensitivity to cisplatin. Overexpressing CDK7 with CDK14 strengthened these effects, demonstrating that CDK7 was a major component in CDK14 activation.

Conclusions

Expression of CDK14 worsened the effects of cisplatin chemotherapy by promoting ESCC proliferation.

Multi-view based integrative analysis of gene expression data for identifying biomarkers

The widespread applications in microarray technology have produced the vast quantity of publicly available gene expression datasets. However, analysis of gene expression data using biostatistics and machine learning approaches is a challenging task due to (1) high noise; (2) small sample size with high dimensionality; (3) batch effects and (4) low reproducibility of significant biomarkers. These issues reveal the complexity of gene expression data, thus significantly obstructing microarray technology in clinical applications. The integrative analysis offers an opportunity to address these issues and provides a more comprehensive understanding of the biological systems, but current methods have several limitations. This work leverages state of the art machine learning development for multiple gene expression datasets integration, classification and identification of significant biomarkers. We design a novel integrative framework, MVIAm - Multi-View based Integrative Analysis of microarray data for identifying biomarkers. It applies multiple cross-platform normalization methods to aggregate multiple datasets into a multi-view dataset and utilizes a robust learning mechanism Multi-View Self-Paced Learning (MVSPL) for gene selection in cancer classification problems. We demonstrate the capabilities of MVIAm using simulated data and studies of breast cancer and lung cancer, it can be applied flexibly and is an effective tool for facing the four challenges of gene expression data analysis. Our proposed model makes microarray integrative analysis more systematic and expands its range of applications.

Identification of key genes and pathways downstream of the β-catenin-TCF7L1 complex in pancreatic cancer cells using bioinformatics analysis

As a key component of the Wnt signaling pathway, the β-catenin-transcription factor 7 like 1 (TCF7L1) complex activates transcription and regulates downstream target genes that serve important roles in the pathology of pancreatic cancer. To identify associated key genes and pathways downstream of the β-catenin-TCF7L1 complex in pancreatic cancer cells, the current study used the gene expression profiles GSE57728 and GSE90926 downloaded from the Gene Expression Omnibus. GSE57728 is an array containing information regarding β-catenin knockdown and GSE90926 was developed by high throughput sequencing to provide information regarding TCF7L1 knockdown. Subsequently, differentially expressed genes (DEGs) were sorted separately and the shared 88 DEGs, including 37 upregulated and 51 downregulated genes, were screened. Clustering analysis of these DEGs was performed by heatmap analysis. Functional and pathway enrichment analyses were then performed using FunRich software and Database for Annotation, Visualization and Integrated Discovery, which revealed that the DEGs were predominantly enriched in terms associated with transport, transcription factor activity, and cytokine and chemokine mediated signaling pathway process. A DEG-associated protein-protein interaction (PPI) network, consisting of 58 nodes and 171 edges, was then constructed using Cytoscape software and the 15 genes with top node degrees were selected as the hub genes. Overall survival (OS) analysis of the 88 DEGs was performed and the relevant gene expression datasets were downloaded from The Cancer Genome Atlas. Consequently, three upregulated and seven downregulated genes were identified to be associated with prognosis. Furthermore, high expression levels of five downregulated genes, including CXCL5, CYP27C1, FUBP1, CDK14 and TRIM24, were associated with worse OS. In addition, CDK14 and TRIM24 were revealed as hub genes in the PPI network and both were confirmed to be involved in the Wnt/β-catenin pathway and phosphoinositide 3-kinase/Akt signaling pathway. Promoter analysis was also applied to the five downregulated DEGs associated with prognosis, which revealed that TCF7L1 may serve as a transcription factor of the DEGs. In conclusion, the genes and pathways identified in the current study may provide potential targets for the diagnosis and treatment of pancreatic cancer.

The role of lncRNA MSC-AS1/miR-29b-3p axis-mediated CDK14 modulation in pancreatic cancer proliferation and Gemcitabine-induced apoptosis

Pancreatic ductal adenocarcinoma (PDAC) remains a leading cause of cancer-related death due to the failure of traditional therapies. In the present study, we attempted to construct a lncRNA-miRNA-mRNA network which may modulate PDAC cell proliferation and Gemcitabine-induced cell apoptosis starting from CDK14, a new member of the CDK family and an oncogene in many cancers. Based on TCGA data, a significant positive correlation was observed between lncRNA MSC-AS1 and CDK14. Moreover, MSC-AS1 expression was upregulated in PDAC tissues. Higher MSC-AS1 expression was correlated with poorer prognosis in patients with PDAC. MSC-AS1 knockdown in Panc-1 and BxPC-3 cells significantly inhibited the cell proliferation. Moreover, miR-29b-3p, which has been reported to act as a tumor suppressor, was predicted to bind to both MSC-AS1 and CDK14. Contrary to MSC-AS1, higher miR-29b-3p expression was correlated to better prognosis in patients with PDAC. In both PDAC cell lines, miR-29b-3p negatively regulated MSC-AS1 and CDK14. As confirmed using luciferase reporter gene and RIP assays, MSC-AS1 served as a ceRNA for miR-29b-3p to counteract miR-29b-mediated CDK14 repression. MSC-AS1 knockdown inhibited CDK14 protein levels and PDAC proliferation and enhanced gemcitabine-induced cell death and apoptosis while miR-29b-3p inhibition exerted an opposing effect; the effect of MSC-AS1 knockdown was partially attenuated by miR-29b-3p inhibition. Taken together, we demonstrated that MSC-AS1/miR-29b-3p axis modulates the cell proliferation and GEM-induced cell apoptosis in PDAC cell lines through CDK14. We provided a novel experimental basis for PDAC treatment from the perspective of lncRNA-miRNA-mRNA network.

LncRNA H19/miR-194/PFTK1 axis modulates the cell proliferation and migration of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a huge challenge due to its high mortality and morbidity; gene therapy might be a promising treatment for PDAC. The critical role of Wnt-signaling pathway in cancer pathogenesis has been widely recognized; cyclin-dependent kinase 14 (CDK14, PFTK1)-induced low-density lipoprotein receptor-related proteins 5/6 (LRP5/6) phosphorylation is an important issue in Wnt-signaling activation. Long noncoding RNA (LncRNA)-microRNA (miRNA)-messenger RNA (mRNA) modulating the pathogenesis of cancers has been regarded as a major mechanism. In the current study, upregulated lncRNAs positively correlated with PFTK1 were analyzed and selected using The Cancer Genome Atlas (TCGA) database. Of them, lncRNA H19 can activate Wnt signaling in cancers. In PDAC tissues, the expression of H19 and PFTK1 were upregulated; H19 knockdown suppressed the cell proliferation and migration of PDAC, while PFTK1 overexpression partially attenuated the suppressive effect of H19 knockdown. As analyzed by TCGA and predicted by online tools, miR-194 was negatively correlated with PFTK1 and might bind to both H19 and PFTK1, which was further confirmed by luciferase reporter and RNA immunoprecipitation assays. Moreover, the effect of H19 knockdown on PFTK1 protein and the cell proliferation and migration could be partially reversed by miR-194 inhibition; H19/miR-194 axis modulated PDAC cell proliferation and migration through PFTK1 downstream Wnt signaling. Results suggested that rescuing miR-194 expression in PDAC can inhibit lncRNA H19 and PFTK1 expression, subsequently suppressing PDAC cell proliferation and migration. Due to the complexity of the lncRNA-miRNA-mRNA network, further in vivo experiments examining potential side effects are needed in future study to explore the clinical application of these findings.

Downregulation of dual-specificity tyrosine-regulated kinase 2 promotes tumor cell proliferation and invasion by enhancing cyclin-dependent kinase 14 expression in breast cancer

Tumor progression is the main cause of death in patients with breast cancer. Accumulating evidence suggests that dual-specificity tyrosine-regulated kinase 2 (DYRK2) functions as a tumor suppressor by regulating cell survival, differentiation, proliferation and apoptosis. However, little is known about the mechanisms of transcriptional regulation by DYRK2 in cancer progression, particularly with respect to cancer proliferation and invasion. Here, using a comprehensive expression profiling approach, we show that cyclin-dependent kinase 14 (CDK14) is a target of DYRK2. We found that reduced DYRK2 expression increases CDK14 expression, which promotes cancer cell proliferation and invasion in vitro, in addition to tumorigenicity in vivo. CDK14 and DYRK2 expression inversely correlated in human breast cancer tissues. We further identified androgen receptor (AR) as a candidate of DYRK2-dependent transcription factors regulating CDK14. Taken together, our findings suggest a mechanism by which DYRK2 controls CDK14 expression to regulate tumor cell proliferation and invasion in breast cancer. Targeting of this pathway may be a promising therapeutic strategy for treating breast cancer.

MicroRNA-613 impedes the proliferation and invasion of glioma cells by targeting cyclin-dependent kinase 14

Increasing evidence has suggested that microRNAs (miRNAs) are critical regulators of tumorigenesis. MicroRNA-613 (miR-613) has recently been reported as a novel tumor-related miRNA that plays an important role in multiple cancers. However, the expression and functional significance of miR-613 in glioma remains unclear. In this study, we aimed to investigate the biological function of miR-613 in glioma. We found that miR-613 expression was frequently downregulated in glioma tissues and cell lines compared with normal controls. Overexpression of miR-613 impeded proliferation and colony formation and induced cell cycle arrest in G0/G1 phase, and also inhibited the invasive ability of glioma cells. By contrast, miR-613 inhibition had the opposite effects. Bioinformatic analysis and dual-luciferase reporter assays showed that miR-613 directly targets the 3'-untranslated region of cyclin-dependent kinase 14 (CDK14). Real-time quantitative PCR and Western blot analysis showed that CDK14 expression is negatively regulated by miR-613. In addition, miR-613 expression was inversely correlated with CDK14 expression in clinical glioma tissues. Moreover, overexpression of miR-613 decreased the protein expression of β-catenin and inhibited the activation of Wnt signaling. Importantly, the antitumor effects of miR-613 were significantly reversed by CDK14 overexpression. Overall, our results show that miR-613 inhibits glioma cell proliferation and invasion by downregulating CDK14, suggesting that miR-613 and CDK14 may serve as potential therapeutic targets for the treatment of glioma.

Genome-Wide Association Study Identifies a New Locus at 7q21.13 Associated with Hepatitis B Virus-Related Hepatocellular Carcinoma

Purpose: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In China, chronic hepatitis B virus (HBV) infection remains the major risk factor for HCC. In this study, we performed a genome-wide association study (GWAS) among Chinese populations to identify novel genetic loci contributing to susceptibility to HBV-related HCC.Experimental Design: GWAS scan is performed in a collection of 205 HBV-related HCC trios (each trio includes an affected proband and his/her both parents), and 355 chronic HBV carriers with HCC (cases) and 360 chronic HBV carriers without HCC (controls), followed by two rounds of replication studies totally consisting of 3,796 cases and 2,544 controls.Results: We identified a novel association signal within the CDK14 gene at 7q21.13 (index rs10272859, OR = 1.28, P = 9.46 × 10^-10). Furthermore, we observed that the at-risk rs10272859[G] allele was significantly associated with higher mRNA expression levels of CDK14 in liver tissues. Chromosome conformation capture assays in liver cells confirmed that a physical interaction exists between the promoter region of CDK14 and the risk-associated SNPs in strong linkage disequilibrium with the index rs10272859 at 7q21.13. This index rs10272859 also showed significant association with the survival of HCC patients.Conclusions: Our findings highlight a novel locus at 7q21.13 conferring both susceptibility and prognosis to HBV-related HCC, and suggest the CDK14 gene to be the functional target of the 7q21.13 locus. Clin Cancer Res; 24(4); 906-15. ©2017 AACR.

miR-216a inhibits osteosarcoma cell proliferation, invasion and metastasis by targeting CDK14

Osteosarcoma (OS) has emerged as the most common primary musculoskeletal malignant tumour affecting children and young adults. Cyclin-dependent kinases (CDKs) are closely associated with gene regulation in tumour biology. Accumulating evidence indicates that the aberrant function of CDK14 is involved in a broad spectrum of diseases and is associated with clinical outcomes. MicroRNAs (miRNAs) are crucial epigenetic regulators in the development of OS. However, the essential role of CDK14 and the molecular mechanisms by which miRNAs regulate CDK14 in the oncogenesis and progression of OS have not been fully elucidated. Here we found that CDK14 expression was closely associated with poor prognosis and overall survival of OS patients. Using dual-luciferase reporter assays, we also found that miR-216a inhibits CDK14 expression by binding to the 3′-untranslated region of CDK14. Overexpression of miR-216a significantly suppressed cell proliferation, migration and invasion in vivo and in vitro by inhibiting CDK14 production. Overexpression of CDK14 in the miR-216a-transfected OS cells effectively rescued the suppression of cell proliferation, migration and invasion caused by miR-216a. In addition, Kaplan–Meier analysis indicated that miR-216a expression predicted favourable clinical outcomes for OS patients. Moreover, miR-216a expression was downregulated in OS patients and was negatively associated with CDK14 expression. Overall, these data highlight the role of the miR-216a/CDK14 axis as a novel pleiotropic modulator and demonstrate the associated molecular mechanisms, thus suggesting the intriguing possibility that miR-216a activation and CDK14 inhibition may be novel and attractive therapeutic strategies for treating OS patients.

High expression of PFTK1 in cancer cells predicts poor prognosis in colorectal cancer

The serine/threonine-protein kinase PFTAIRE 1 (PFTK1) is a member of the cyclin‑dependent kinase family that is highly expressed in several malignant tumors, including hepatocellular carcinoma, esophageal, breast and gastric cancers, and glioma. It contributes to tumor progression and influences tumor prognosis. However, the expression and clinicopathological significance of PFTK1 in human colorectal cancer (CRC) remain to be elucidated. The present study aimed to examine the expression of PFTK1 and to evaluate the clinical significance of its expression in human CRC. Reverse transcription‑quantitative polymerase chain reaction was performed on 10 fresh CRC and 10 surrounding normal tissue samples to detect and compare the expression of PFTK1 mRNA in CRC and normal colorectal tissues. Immunohistochemistry was performed on 179 CRC tissue specimens and 47 control samples of normal colorectal lesions to characterize the expression of PFTK1 protein. Kaplan‑Meier overall survival (OS) rate and Cox regression analyses were performed to evaluate the prognosis of patients with CRC. The expression of PFTK1 mRNA in CRC tissues (1.433±0.168) was significantly higher compared with normal tissues (0.853±0.107; t=1.97 ('t' was the value obtained from quantification of the mRNA data, following a paired t‑test), P=0.008). High PFTK1 expression in cancerous cells was detected in 92 of the CRC specimens (51.40%), and high levels of PFTK1 were associated with tumor node metastasis (TNM) stage (P=0.042), tumor classification (P=0.022) and preoperative carcinoembryonic antigen (CEA) level (P<0.001). Kaplan‑Meier OS rate and Cox regression analysis revealed that high PFTK1 expression level (hazard ratio (HR)=1.999; P=0.019) was an independent prognostic factor of CRC patients. The degree of differentiation (HR, 0.368, P=0.003), TNM classification (HR, 2.118, P=0.001) and preoperative CEA level (HR, 2.302, P=0.003) were also predictors of the prognosis of patients with CRC. The present study suggested that PFTK1 may be a potential anticancer target and prognostic marker in patients with CRC.

Knockdown of PFTAIRE Protein Kinase 1 (PFTK1) Inhibits Proliferation, Invasion, and EMT in Colon Cancer Cells

PFTK1 is a member of the cyclin-dependent kinase (CDK) family and is upregulated in many types of tumors. However, its expression and role in colon cancer remain unclear. In this study, we aimed to investigate the expression and function of PFTK1 in colon cancer. Our results showed that PFTK1 was highly expressed in colon cancer cell lines. The in vitro experiments demonstrated that knockdown of PFTK1 inhibited the proliferation, migration, and invasion of colon cancer cells as well as the epithelial-to-mesenchymal transition (EMT) progress. Furthermore, knockdown of PFTK1 suppressed the expression of Shh as well as Smo, Ptc, and Gli-1 in colon cancer cells. Taken together, these results suggest that knockdown of PFTK1 inhibited the proliferation and invasion of colon cancer cells as well as the EMT progress by suppressing the Sonic hedgehog signaling pathway. Therefore, these findings reveal that PFTK1 may be a potential therapeutic target for the treatment of colon cancer.

Knockdown of PFTK1 Expression by RNAi Inhibits the Proliferation and Invasion of Human Non-Small Lung Adenocarcinoma Cells

PFTK1 (PFTAIRE protein kinase 1), also named CDK14 (cyclin-dependent kinase 14), is a member of the cell division cycle 2 (CDC2)-related protein kinase family. It is highly expressed in several malignant tumors. However, the role of PFTK1 in the progression of non-small cell lung cancer (NSCLC) is still elusive. In this study, we aimed to explore the expression and function of PFTK1 in NSCLC cells. Our results showed that PFTK1 was significantly upregulated in human NSCLC cell lines. Silencing the expression of PFTK1 inhibited the proliferation of NSCLC cells. In addition, silencing the expression of PFTK1 endowed NSCLC cells with decreased migration and invasion abilities, as well as epithelial-mesenchymal transition (EMT) progress in A549 cells. A mechanistic study showed that knockdown of PFTK1 inhibited the expression of β-catenin, cyclin D1, and c-Myc in A549 cells. In summary, we report that small interfering RNA (siRNA)-PFTK1 might inhibit the proliferation and invasion of NSCLC cells by suppressing the Wnt/β-catenin signaling pathway. Therefore, PFTK1 may represent a novel therapeutic target for the treatment of NSCLC.

miR-455 inhibits breast cancer cell proliferation through targeting CDK14

Breast cancer is the most frequently occurring cancer in women worldwide, microRNAs (miRNAs) play critical role in the initiation and progression of breast cancer. Here, we studied the effect of miR-455 on cell proliferation of breast cancer, and found that miR-455 was downregulated in breast cancer tissues and cells. Its overexpression inhibited cell proliferation, whereas its knockdown promoted cell proliferation of breast cancer. We found a Cdc2-related protein kinase CDK14 was the target of miR-455, when the 3^'UTR of CDK14 was cloned into luciferase reporter vector and transfected into cells, miR-455 mimic could inhibit the luciferase activity in a dose-dependent manner, miR-455 inhibitor increased the luciferase activity, but the mutant miR-455 mimic couldn't change the luciferase activity, suggesting miR-455 directly bound to the 3^'UTR of CDK14. Meanwhile, we also found miR-455 inhibited Cyclin D1 expression and promoted p21 expression, confirming miR-455 inhibited cell proliferation. Double knockdown of miR-455 and CDK14 inhibited the proliferation of breast cancer cell, confirming miR-455 inhibiting cell proliferation by targeting CDK14. Moreover, miR-455 levels were negatively correlated with CDK14 levels in breast cancer tissues. Our finding revealed miR-455 inhibits breast cancer cell proliferation through targeting CDK14, it might be a target for breast cancer therapy.

Activity-Based Protein Profiling Shows Heterogeneous Signaling Adaptations to BRAF Inhibition

Patients with BRAF V600E mutant melanoma are typically treated with targeted BRAF kinase inhibitors, such as vemurafenib and dabrafenib. Although these drugs are initially effective, they are not curative. Most of the focus to date has been upon genetic mechanisms of acquired resistance; therefore, we must better understand the global signaling adaptations that mediate escape from BRAF inhibition. In the current study, we have used activity-based protein profiling (ABPP) with ATP-analogue probes to enrich kinases and other enzyme classes that contribute to BRAF inhibitor (BRAFi) resistance in four paired isogenic BRAFi-naïve/resistant cell line models. Our analysis showed these cell line models, which also differ in their PTEN status, have considerable heterogeneity in their kinase ATP probe uptake in comparing both naïve cells and adaptations to chronic drug exposure. A number of kinases including FAK1, SLK, and TAOK2 had increased ATP probe uptake in BRAFi resistant cells, while KHS1 (M4K5) and BRAF had decreased ATP probe uptake in the BRAFi-resistant cells. Gene ontology (GO) enrichment analysis revealed BRAFi resistance is associated with a significant enhancement in ATP probe uptake in proteins implicated in cytoskeletal organization and adhesion, and decreases in ATP probe uptake in proteins associated with cell metabolic processes. The ABPP approach was able to identify key phenotypic mediators critical for each BRAFi resistant cell line. Together, these data show that common phenotypic adaptations to BRAF inhibition can be mediated through very different signaling networks, suggesting considerable redundancy within the signaling of BRAF mutant melanoma cells.