Cell Cycle-related Kinase Expression Research Articles

Effects of the Targeted Regulation of CCRK by miR-335-5p on the Proliferation and Tumorigenicity of Human Renal Carcinoma Cells.

Cell cycle-related kinase (CCRK) is most closely related to cyclin-dependent protein kinase, which may activate cyclin-dependent kinase 2 and is associated with the growth of human cancer cells. However, the expression and function of CCRK in the pathogenesis of clear cell renal cell cancer (ccRCC) are unclear. Herein, this research aimed to explore the potential mechanism of the targeted regulation of CCRK by miR-335-5p on the proliferation and tumorigenicity of human ccRCC cells. The results showed that CCRK was significantly overexpressed in ccRCC tissues and cells, and knockdown of the CCRK expression by shRNA inhibited cell proliferation in vitro and in vivo and enhanced cell apoptosis in vitro, which indicated that CCRK could be a potential target for antitumour drugs in the treatment of ccRCC. Moreover, miR-335-5p was found to bind directly to the 3′ untranslated region of CCRK, was expressed at markedly low levels in ccRCC cells, and was closely associated with the tumour stage. The overexpression of CCRK partially reversed the inhibitory effects of miR-335-5p on the cell growth of ccRCC, which implied that miR-335-5p could serve as a promising tumour inhibitor for ccRCC. In summary, CCRK could serve as an alternative antitumour drug target, and miR-335-5p could be a promising therapeutic tumour inhibitor for ccRCC treatment.

Abstract 1485: Hepatic cell cycle-related kinase shapes a metastatic-prone liver microenvironment via crosstalk between myeloid-derived suppressor cell and natural killer T cell

Abstract Metastasis is a prominent cause of cancer-related death governed by both cancer cell-intrinsic mechanisms and extrinsic microenvironment. Clinical observations demonstrated liver as a common metastatic site for various cancers, which may be due to its immune tolerant environment. Myeloid-derived suppressor cell (MDSC) is a heterogeneous cell population of immature myeloid cells that contribute to the formation of a favorable metastatic environment partially via suppression of immune effector cells. However, the underlying mechanisms in liver tropism of tumor metastasis remain poorly understood. We have previously discovered that cell cycle-related kinase (CCRK) can promote primary hepatocellular carcinoma (HCC) development via MDSCs (Gut 2018; Nat Commun accepted). Here we hypothesize that the accumulation of hepatic MDSCs induced by CCRK may contribute to the formation of a favorable metastatic liver microenvironment. By the construction of a liver-specific CCRK inducible transgenic (TG) mouse model by a Cre/loxP system, induction of CCRK expression by tamoxifen injection could increase CD11b+Gr-1+Ly6G+Ly6Clow polymorphonuclear (PMN)-MDSCs liver accumulation specifically in male mice with upregulated Cxcl1 and Gcsf expression. Intrahepatic injection of a mouse hepatoma cell line Hep1-6 in male TG mice developed larger tumors compared to control and positively associated with increased PMN-MDSCs levels in liver. Moreover, the tumorigenicity was abolished by PMN-MDSC depletion. Notably, intrasplenic injection of a mouse melanoma cell line B16F10 exhibited increased level of liver-infiltrating PMN-MDSCs and enhanced liver metastasis in male TG mice compared to control mice. Moreover, depletion of PMN-MDSCs suppressed metastasis in liver. Mechanistically, anti-tumor NKT cells, rather than NK cells and CD8+T cells, were negatively correlated with tumor weight and MDSC proportion, indicating the potential crosstalk between MDSC and NKT in liver metastasis. Our findings suggest that hepatic CCRK expression create a tumor growth- and metastasis-supportive liver microenvironment via enhancing immunosuppression. Additional colorectal cancer metastasis models will be evaluated in our established TG mice. Moreover, the roles and underlying mechanisms of CCRK-PMN-MDSC interactions in the establishment of liver metastasis await further investigation. This project is supported by Collaborative Research Fund C4017-14G and the Focused Innovations Scheme 1907309. Citation Format: Xuezhen ZENG, Jingying Zhou, Zhewen Xiong, Hanyong Sun, Weiqin Yang, Wenshu Tang, Yu Feng, Alfred Sze-Lok Cheng. Hepatic cell cycle-related kinase shapes a metastatic-prone liver microenvironment via crosstalk between myeloid-derived suppressor cell and natural killer T cell [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1485.

Androgen Receptor Promotes Gastric Carcinogenesis via Upregulating Cell Cycle-Related Kinase Expression.

Gastric cancer (GC) is a leading global health problem as it is the fifth most common cancer type and the third most common cause of cancer-related deaths worldwide. In most areas of the world, the incidence rate of GC is 1.5- to 3-fold higher in males than in females. The androgen receptor (AR) is an independent adverse prognostic factor in patients with GC. However, the mechanism by which AR regulates the progression of GC remains unclear. In this study, we found that AR expression was upregulated in 6/8 GC cell lines, and this expression was higher than that in immortalized gastric cells. AR expression was also higher in GC tissues than in adjacent tissues. Moreover, the ectopic expression of AR promoted the colony formation ability, migration and invasion of GC cells. In contrast, AR knockdown had the opposite effects on GC cell lines. Remarkably, we found that AR regulated cell cycle-related kinase (CCRK) expression through transcriptional mechanisms. The AR-CCRK axis promoted GC development through the phosphorylation of GSK3β and β-catenin. Furthermore, TCGA data revealed that high expression of AR or CCRK was related to poor prognosis in GC patients. The prognosis was significantly worse in patients with concurrent high AR and CCRK expression than in patients with low AR and CCRK expression. In conclusion, our study demonstrated that AR and CCRK acted as oncogenes in GC progression. However, their clinical roles require further exploration.

Abstract 3752: A cell cycle-related kinase (CCRK) self-regulatory circuitry in NAFLD-associated hepatocarcinogenesis

Abstract Background and aim: Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome including obesity and diabetes which elevate the risk of hepatocellular carcinoma (HCC). Accumulating evidence has unmasked the molecular linkage between androgen receptor (AR) signaling and gender disparity in NAFLD and HCC incidence. Our previous genome-wide location and functional analysis has pinpointed cell cycle-related kinase (CCRK) as a critical mediator of AR oncogenic activity in hepatitis B virus-associated HCC through glycogen synthase kinase-3β (GSK-3β)/β-catenin signaling (1-3). Here we investigated whether CCRK plays an oncogenic role in NAFLD-related HCC. Methods: We investigated the functional role of CCRK in a high-fat high carbohydrate diet-induced obesity model exposed to low-dose diethylnitrosamine using lentiviral-mediated gene knockdown, followed by measurement of glucose/lipid metabolism via intraperitoneal glucose tolerance test and triglyceride/non-esterified fatty acids levels, and HCC incidence. Gene regulation was assessed by chromatin immunoprecipitation, site-directed mutagenesis, luciferase reporter, co-immunoprecipitation and expression analyses. Results: Lentiviral-mediated Ccrk silencing in male mice significantly reduced obesity-promoted tumor multiplicity and size by >70%. The reduced tumorigenicity was also associated with significant restoration of circulating metabolic profiles and reduction in hepatocellular lipid level. Mechanistic studies demonstrated that the pro-inflammatory cytokine interleukin-6 (IL-6) triggered signal transducer and activator of transcription 3 (STAT3) signaling to up-regulate CCRK expression in an AR-dependent manner. Simultaneously, the phosphorylation of STAT3 by CCRK facilitated the co-occupancy of CCRK promoter by STAT3-AR complex and its subsequent transcriptional activation, thus forming a self-reinforcing circuitry. In addition, both in vitro and in vivo data suggested that CCRK phosphorylated GSK-3β to activate not only β-catenin but also mechanistic target of rapamycin complex 1 (mTORC1) signaling pathways that are crucial for cell survival, proliferation and lipogenesis. Furthermore, transgenic over-expression of CCRK in mouse liver led to concordant activation of STAT3, β-catenin and mTORC1 signaling pathways. Conclusion: Our findings highlight the critical role of CCRK in a self-reinforcing circuitry that regulates NAFLD-associated hepatocarcinogenesis and offer novel therapeutic strategies to combat this dreadful disease in an era of global obesity. Acknowledgement: This project was supported by the Collaborative Research Fund C4017-14G and General Research Fund 14102914.

Expression of CCRK in small cell lung cancer and its clinical significance

Objective To investigate the pathogenesis of small cell lung cancer (SCLC) and to explore the expression of cell cycle related kinase (CCRK) in SCLC and its clinical significance. Methods Reverse transcription polymerase chain reaction (RT-PCR) and Western blot were performed to examine expression of CCRK in SCLC and normal tissues. Results The expressions of gene [(0.51±0.11)IU/L] and protein [(0.61±0.13)IU/L] of CCRK in SCLC tissues were significantly higher than normal tissues [(0.30±0.08)IU/L, (0.34±0.09)IU/L] (P 0.05). Conclusions The expressions of gene and protein of CCRK in SCLC tissues were significantly higher than normal tissues. CCRK promoted the occurrence and progress of SCLC. Chem can restrain effectually the excessive expression of CCRK. The expressions of gene and protein of CCRK in the different clinical curative effect group had significant difference. Key words: Lung neoplasms/ME; Cyclin-dependent kinases/ME

A CCRK-EZH2 epigenetic circuitry drives hepatocarcinogenesis and associates with tumor recurrence and poor survival of patients

Aberrant chromatin modification is a key feature of hepatocellular carcinoma (HCC), which is characterized by strong sexual dimorphism. Both enhancer of zeste homolog 2 (EZH2) and cell cycle-related kinase (CCRK) contribute to hepatocarcinogenesis, yet whether the two oncogenic factors have functional crosstalk is unknown. Cellular proliferation and tumorigenicity upon transgenic expression and RNA interference were determined by colony formation and soft agar assays, xenograft, orthotopic and diethylnitrosamine-induced HCC models. Gene regulation was assessed by chromatin immunoprecipitation, site-directed mutagenesis, luciferase reporter, co-immunoprecipitation and expression analyses. Protein levels in clinical specimens were correlated with clinicopathological parameters and patient survival rates. Ectopic CCRK expression in immortalized human liver cells increased EZH2 and histone H3 lysine 27 trimethylation (H3K27me3) to stimulate proliferation and tumor formation. Conversely, knockdown of CCRK reduced EZH2/H3K27me3 levels and decreased HCC cell growth, which could be rescued by EZH2 over-expression. Mechanistically, GSK-3β phosphorylation by CCRK activated a β-catenin/TCF/E2F1/EZH2 transcriptional feedback loop to epigenetically enhance androgen receptor (AR) signaling. Simultaneously, the phosphorylation of AKT/EZH2 by CCRK facilitated the co-occupancy of CCRK promoter by EZH2-AR and its subsequent transcriptional activation, thus forming a self-reinforcing circuitry. Lentiviral-mediated knockdown of CCRK, which abrogated the phosphorylation-transcriptional network, prevented diethylnitrosamine-induced tumorigenicity. More importantly, the hyperactivation of the CCRK-EZH2 circuitry in human HCCs correlated with tumor recurrence and poor survival. These findings uncover an epigenetic vicious cycle in hepatocarcinogenesis that operates through reciprocal regulation of CCRK and EZH2, providing novel therapeutic strategy for HCC.

Cell cycle-related kinase mediates viral-host signalling to promote hepatitis B virus-associated hepatocarcinogenesis

BackgroundAndrogen receptor (AR) signalling contributes to male predominance in hepatocellular carcinoma (HCC), which is more pronounced in HBV-endemic areas. Cell cycle-related kinase (CCRK) is essential for AR-induced hepatocarcinogenesis but its...

Cell cycle–related kinase links androgen receptor and β-catenin signaling in hepatocellular carcinoma: Why are men at a loss?

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. It is more prevalent in men than in women. Related to this, recent genetic studies have revealed a causal role for androgen receptor (AR) in hepatocarcinogenesis, but the underlying molecular mechanism remains unclear. Here, we used genome-wide location and functional analyses to identify a critical mediator of AR signaling—cell cycle–related kinase (CCRK)—that drives hepatocarcinogenesis via a signaling pathway dependent on β-catenin and T cell factor (TCF). Ligand-bound AR activated CCRK transcription and protein expression via direct binding to the androgen-responsive element of the CCRK promoter in human HCC cell lines. In vitro analyses showed that CCRK was critical in human cell lines for AR-induced cell cycle progression, hepatocellular proliferation, and malignant transformation. Ectopic expression of CCRK in immortalized human liver cells activated β-catenin/TCF signaling to stimulate cell cycle progression and to induce tumor formation, as shown in both xenograft and orthotopic models. Conversely, knockdown of CCRK decreased HCC cell growth, and this could be rescued by constitutively active β-catenin or TCF. In primary human HCC tissue samples, AR, CCRK, and β-catenin were concordantly overexpressed in the tumor cells. Furthermore, CCRK overexpression correlated with the tumor staging and poor overall survival of patients. Our results reveal a direct AR transcriptional target, CCRK, that promotes hepatocarcinogenesis through the upregulation of β-catenin/TCF signaling.

Cell cycle–related kinase is a direct androgen receptor–regulated gene that drives β-catenin/T cell factor–dependent hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. It is more prevalent in men than women. Related to this, recent genetic studies have revealed a causal role for androgen receptor (AR) in hepatocarcinogenesis, but the underlying molecular mechanism remains unclear. Here, we used genome-wide location and functional analyses to identify a critical mediator of AR signaling - cell cycle-related kinase (CCRK) - that drives hepatocarcinogenesis via a signaling pathway dependent on β-catenin and T cell factor (TCF). Ligand-bound AR activated CCRK transcription and protein expression via direct binding to the androgen-responsive element of the CCRK promoter in human HCC cell lines. In vitro analyses showed that CCRK was critical in human cell lines for AR-induced cell cycle progression, hepatocellular proliferation, and malignant transformation. Ectopic expression of CCRK in immortalized human liver cells activated β-catenin/TCF signaling to stimulate cell cycle progression and to induce tumor formation, as shown in both xenograft and orthotopic models. Conversely, knockdown of CCRK decreased HCC cell growth, and this could be rescued by constitutively active β-catenin or TCF. In primary human HCC tissue samples, AR, CCRK, and β-catenin were concordantly overexpressed in the tumor cells. Furthermore, CCRK overexpression correlated with the tumor staging and poor overall survival of patients. Our results reveal a direct AR transcriptional target, CCRK, that promotes hepatocarcinogenesis through the upregulation of β-catenin/TCF signaling.

Abstract 2170: Dissecting the oncogenic function of a novel androgen receptor-dependent direct target, cell cycle-related kinase (CCRK), in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths worldwide with a gender prevalence observed in men. Recent genetic studies using knockout mouse models have revealed the causal role of androgen receptor (AR) in hepatocarcinogenesis but the underlying molecular mechanism remains unclear. Here we used genome-wide location and functional analyses to show that cell cycle-related kinase (CCRK) is a direct critical mediator of AR signaling. Chromatin immunoprecipitation microarray identified over 200 high-confidence AR direct target genes in HCC cells of which cell cycle regulators were significantly enriched (n = 21; p < 0.0001). Because CCRK has the highest AR binding affinity amongst the identified cell cycle regulators, its regulation, function and expression in HCC were further investigated. Ligand-activated AR was recruited to the CCRK promoter and increased CCRK expression. AR-induced cell cycle progression was abrogated by siRNA-mediated knockdown of CCRK. On the contrary, over-expression of CCRK rescued the G1 arrest induced by AR knockdown. Ectopic CCRK expression in human immortal liver cells induced anchorage-dependent and -independent growth and tumor formation in immunodeficient mice, whereas CCRK inhibition decreased HCC cell growth in vitro and in vivo; demonstrating the strong oncogenic capacity of CCRK in HCC. Mechanistically, CCRK activated β-catenin/T-cell factor (TCF) signaling through phosphorylation of glycogen synthase kinase-3β to increase the expression of downstream pro-proliferative genes, cyclin D1 and epidermal growth factor receptor. Inhibition of β-catenin/TCF signaling significantly attenuated CCRK-induced cell cycle progression, colony formation and tumorigenicity. Conversely, HCC cell growth inhibition by CCRK knockdown was rescued by constitutively active form of β-catenin or TCF. Importantly, AR, CCRK, and active β-catenin were markedly over-expressed and positively correlated among each other in HCC specimens (p < 0.001). Furthermore, CCRK over-expression was significantly associated with tumor staging and poor disease-free survival of patients (p < 0.05), emphasizing the clinical importance of CCRK in HCC. In conclusion, our findings reveal a novel interplay between AR and β-catenin where activated AR transcriptionally up-regulates CCRK expression, thereby activating β-catenin/TCF signaling to induce aberrant cell proliferation. Dissection of this highly activated AR-CCRK-β-catenin/TCF axis sheds new mechanistic insight into hepatocarcinogenesis and provides novel therapeutic targets for the treatment of this and other male-predominant cancers. Acknowledgements: This study was partially supported by the Research Grant Council General Research Fund (462710) and the Direct Grant from the Chinese University of Hong Kong. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2170. doi:10.1158/1538-7445.AM2011-2170

Cell cycle‐related kinase supports ovarian carcinoma cell proliferation via regulation of cyclin D1 and is a predictor of outcome in patients with ovarian carcinoma

Our previous study has suggested that the cell cycle-related kinase (CCRK) is a putative candidate oncogene in glioblastoma tumorigenesis. The potential oncogenic role of CCRK and its clinical/prognostic significance, however, in ovarian carcinoma are unclear. In this study, CCRK expression was examined by immunohistochemistry in a series of ovarian carcinoma tissues. Overexpression of CCRK was detected in 53% of the ovarian carcinomas, and it was positively correlated with an ascending histological grade and/or advanced clinical stage of the disease (p < 0.05). In addition, overexpression of CCRK in ovarian carcinoma was determined to be a strong and an independent predictor of short overall survival (p < 0.05). In ovarian carcinoma cells, CCRK knockdown by RNAi led to a G1 phase cell cycle arrest, while CCRK overexpression by stable transfection of CCRK-containing plasmid pcDNA-CCRK promoted cell proliferation in vitro and tumor growth in vivo. In addition, CCRK knockdown was found to reduce cyclin D1 expression. Consistently, CCRK overexpression increased cyclin D1 expression, and furthermore, a significant correlation between expression of CCRK and cyclin D1 in ovarian carcinomas was observed (p < 0.001). These findings suggest a potential important role of CCRK in the control of cell proliferation via regulation of cyclin D1 expression, and the overexpression of CCRK, as detected by immunohistochemistry, is an independent molecular marker for shortened survival time of patients with ovarian carcinoma.

Characterization of a Novel Cardiac Isoform of the Cell Cycle‐related Kinase

We examined a genomic profile in monkey hearts subjected to myocardial infarction (MI) followed by pacing‐induced heart failure (HF), to identify novel mechanisms involved in the pathogenesis of HF. One candidate was the transcript encoding the cell cycle‐related kinase (CCRK), which decreased by 50% in HF (P&lt;0.05). The CCRK sequence cloned from the heart showed the same N‐terminal kinase domain as the “generic” isoform cloned previously, but a different C‐terminal half due to alternative splicing with frame shift. Expression of the protein, confirmed by monoclonal antibody, was limited to heart, liver and kidney. Upon overexpression in cardiac myocytes, both the generic and cardiac isoforms promoted cell growth and decreased apoptosis (P&lt;0.05 vs control). The “generic” but not the cardiac CCRK interacted with cyclin H and casein kinase 2 in a yeast two‐hybrid, phosphorylated the cyclin‐dependent kinase 2, and increased the number of myocytes in the S and G2 phases of the cell cycle (P&lt;0.05 vs control). Therefore, the heart expresses a variant of CCRK, which promotes cardiac cell growth and survival similarly to the “generic” form, but both isoforms differ in terms of protein‐protein interactions, substrate specificity and re‐entry in the cell cycle. Antagonizing the down‐regulation of CCRK expression in the transition to HF could protect the heart and enhance regeneration of failing myocardium.

Cell Cycle-Related Kinase: A Novel Candidate Oncogene in Human Glioblastoma

Median survival for patients with glioblastoma multiforme, the most aggressive glioma, is only 12-15 months, despite multimodal treatment that includes surgery, chemotherapy, and radiotherapy. Thus, identification of genes that control the progression of glioblastoma multiforme is crucial for devising new therapies. We investigated the involvement of cell cycle-related kinase (CCRK), a novel protein kinase that is homologous to cyclin-dependent kinase 7, in glioblastoma multiforme carcinogenesis. We analyzed the expression levels of CCRK in 26 glioma patient samples (19 high-grade and seven low-grade) and normal brain by semiquantitative reverse transcription-polymerase chain reaction assays. CCRK expression was knocked down in human glioma U-373 MG and U-87 MG cells with small-interfering RNAs and short hairpin RNAs (siCCRK and shCCRK, respectively), and cell proliferation, cell cycle distribution, and cyclin-dependent kinase 2 (CDK2) phosphorylation were examined. A subcutaneous nude mouse xenograft model (n = 4 mice per group) was used to study the effect of CCRK knockdown and overexpression on tumorigenicity and growth of glioblastoma multiforme cells in vivo. All statistical tests were two-sided. CCRK mRNA was elevated at least 1.5-fold and as much as 3.7-fold in 14 (74%) of 19 high-grade glioblastoma multiforme patient samples and in four (80%) of five glioma cell lines examined compared with normal brain tissue. Suppression of CCRK by siCCRK inhibited the proliferation of U-373 MG and U-87 MG glioblastoma cells in a time- and dose-dependent manner. The growth-inhibiting effect of siCCRK was mediated via G1- to S-phase cell cycle arrest and reduced CDK2 phosphorylation. CCRK knockdown statistically significantly suppressed glioma cell growth in vivo as indicated by the mean tumor volumes at week 6 after tumor cell injection (U-373-control = 1352 mm3, U-373-shCCRK = 294 mm3, difference = 1058 mm3, 95% confidence interval [CI] = 677 to 1439 mm3, P<.001; U-87-control = 1910 mm3, U-87-shCCRK = 552 mm3, difference = 1358 mm3, 95% CI = 977 to 1739 mm3, P<.001). CCRK is a candidate oncogene in glioblastoma multiforme tumorigenesis.