Overexpression of PFTK1 predicts resistance to chemotherapy in patients with oesophageal squamous cell carcinoma

Cyclin dependent kinase 14 as a paclitaxel-resistant marker regulated by the TGF-β signaling pathway in human ovarian cancer

Cyclin dependent kinase 14 (CDK14) plays a central role in the control of cell proliferation and cell cycle progression. However, the specific function and regulatory mechanism of CDK14 on paclitaxel (PTX) resistance in ovarian cancer (OC) remain unclear. The present study demonstrated that CDK14 was overexpressed in OC tissues and cells at mRNA and protein levels detected by qRT-PCR, Western blot, and immunohistochemistry. Survival analysis showed that elevated CDK14 was related to the poor prognosis of OC patients. Overexpression of CDK14 was correlated with chemoresistance in OC. The expression level of CDK14 was higher in PTX-resistant OC cells (SK3R-PTX and OV3R-PTX) than in their counterpart-sensitive cells (SK-OV-3 and OVCAR-3). Knockdown of CDK14 decreased multidrug resistance 1 (MDR1) and β-catenin expression in SK3R-PTX and OV3R-PTX cells and resensitized OC cells to PTX by decreasing cell proliferation and inducing cell apoptosis. Administration of transforming growth factor (TGF)-β1 decreased CDK14 protein in PTX-resistant OC cells. The inhibitory effect of TGF-β1 on CDK14 expression was abolished in the presence of a TGF-β type I receptor kinase inhibitor (SB-431542). Furthermore, TGF-β signal transducer Smad2 protein directly bound to the region -437 to -446 upstream of the CDK14 transcription start site (TSS), resulting in downregulating the expression of CDK14. These data indicate that CDK14 is a PTX-resistant marker and is regulated by the TGF-β signaling pathway. Targeting CDK14 to enhance the sensitivity of PTX may provide a new therapeutic strategy for reversing the PTX resistance in OC.

Cyclins and cyclin-dependent kinases: from biology to tumorigenesis and therapeutic opportunities

The discussion on cell proliferation cannot be continued without taking a look at the cell cycle regulatory machinery. Cyclin-dependent kinases (CDKs), cyclins, and CDK inhibitors (CKIs) are valuable members of this system and their equilibrium guarantees the proper progression of the cell cycle. As expected, any dysregulation in the expression or function of these components can provide a platform for excessive cell proliferation leading to tumorigenesis. The high frequency of CDK abnormalities in human cancers, together with their druggable structure has raised the possibility that perhaps designing a series of inhibitors targeting CDKs might be advantageous for restricting the survival of tumor cells; however, their application has faced a serious concern, since these groups of serine-threonine kinases possess non-canonical functions as well. In the present review, we aimed to take a look at the biology of CDKs and then magnify their contribution to tumorigenesis. Then, by arguing the bright and dark aspects of CDK inhibition in the treatment of human cancers, we intend to reach a consensus on the application of these inhibitors in clinical settings.

MiR-205 Inhibits Sporadic Vestibular Schwannoma Cell Proliferation by Targeting Cyclin-Dependent Kinase 14

BACKGROUND

Sporadic vestibular schwannoma (VS) is a benign primary tumor that arises from the vestibular nerve. Growing VS can negatively compress the brain stem, which can lead to death. MicroRNAs (miRNAs) can negatively regulate target genes at the post-transcriptional level and are critical in tumorigenesis. Studies have demonstrated the tumor suppressive function of microRNA-205-5p (miR-205) across many cancers, but no studies have evaluated the role of miR-205 in sporadic VS. We conducted this study to examine the role of miR-205 in sporadic VS cell proliferation.

METHODS

We evaluated miR-205 expression in sporadic VS tissues and normal great auricular nerve by real-time quantitative polymerase chain reaction. Then, we transfected miR-205 mimics and control oligonucleotides into sporadic VS primary cells to examine the functional significance of miR-205 expression at a cellular level by CCK8 and colony formation and used dual-luciferase reporter assays to find the target gene of miR-205.

RESULTS

We determined that miR-205 levels were downregulated in sporadic VS tissues in comparison to normal controls. In functional assays, miR-205 suppressed proliferation and colony formation ability of sporadic VS cells. CDK14 (cyclin-dependent kinase 14) was identified as a target gene of miR-205 by bioinformatics, and validated using dual-luciferase reporter assays. Moreover, miR-205 overexpression inhibited levels of phosphorylated PI3K and Akt.

CONCLUSIONS

These findings suggested that miR-205 suppressed sporadic VS proliferation by targeting CDK14 and may be considered as a potential drug therapy for sporadic VS treatment in the future.

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.

MiR-542-3p, a microRNA targeting CDK14, suppresses cell proliferation, invasiveness, and tumorigenesis of epithelial ovarian cancer

MicroRNA-542-3p (miR-542-3p) has been implicated in several cancers; however, its precise role in ovarian cancer is unclear. In this study, we found that miR-542-3p was significantly downregulated in epithelial ovarian cancer (EOC) tissues and cell lines. Functional assays showed that overexpression of miR-542-3p suppressed tumor cell proliferation, migration, and invasion in vitro, whereas miR-542-3p knockdown dramatically promoted tumor cell proliferation and invasion. An in vivo assay also revealed that miR-542-3p overexpression significantly attenuated tumor growth. Mechanistically, the gene of cyclin-dependent kinase 14 (CDK14) was identified as a novel target of miR-542-3p. CDK14 overexpression reversed the suppressive effects of miR-542-3p in ovarian cancer cells. Collectively, these results suggest that miR-542-3p functions as a tumor-suppressive miRNA in ovarian cancer by directly targeting CDK14. Our data provide novel insights into potential future treatments for patients with ovarian cancer.

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.

Predictive biomarkers for response of esophageal cancer to chemo(radio)therapy: A systematic review and meta-analysis

BACKGROUND

Esophageal cancer remains a major public health issue worldwide. In clinical practice, chemo(radio)therapy is an important approach to patients with esophageal cancer. Only the part of patients who respond to chemo(radio)therapy achieve better long-term outcome. In this case, predictive biomarkers for response of esophageal cancer patients treated with chemo(radio)therapy are of importance. Meta-analysis of P53 for predicting esophageal cancer response has been reported before and is not included in our study. We performed a systematic review and meta-analysis to summarize and evaluate the biomarkers for predicting response to chemo(radio)therapy.

METHOD

PubMed, Web of Science and the Ovid databases were searched to identify eligible studies published in English before March 2017. The risk ratio (or relative risk, RR) was retrieved in articles regarding biomarkers for predicting response of esophageal cancer patients treated with neoadjuvant therapy or chemo(radio)therapy. Fixed and random effects models were used to undertake the meta-analysis as appropriate.

RESULT

Forty-six articles reporting 56 biomarkers correlated with the response were finally included. Meta-analyses were carried out when there was more than one study related to the reported biomarker. Results indicated that low expression of (or IHC-negative) COX2, miR-200c, ERCC1 and TS was individually associated with prediction of response. The RR was 1.64 (n = 202, 95% CI 1.22-2.19, P < 0.001), 1.96 (n = 162, 95% CI 1.36-2.83, P < 0.001), 2.55 (n = 206, 95% CI 1.80-3.62, P < 0.001) and 1.69 (n = 144, 95% CI 1.10-2.61, P = 0.02), respectively. High expression of (or IHC-positive) CDC25B and p16 was individually related to prediction of response. The RR was 0.62 (n = 159, 95% CI 0.43-0.89, P = 0.01) and 0.62 (n = 142, 95% CI 0.43-0.91, P = 0.01), respectively.

CONCLUSION

Low expression of (or IHC-negative) COX2, miR-200c, ERCC1 and TS, or high expression of (or IHC-positive) CDC25B and p16 are potential biomarkers for predicting the response of esophageal cancer patients treated with chemo(radio)therapy.

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 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.

Structure and inhibitor specificity of the PCTAIRE-family kinase CDK16

CDK16 (also known as PCTAIRE1 or PCTK1) is an atypical member of the cyclin-dependent kinase (CDK) family that has emerged as a key regulator of neurite outgrowth, vesicle trafficking and cancer cell proliferation. CDK16 is activated through binding to cyclin Y via a phosphorylation-dependent 14-3-3 interaction and has a unique consensus substrate phosphorylation motif compared with conventional CDKs. To elucidate the structure and inhibitor-binding properties of this atypical CDK, we screened the CDK16 kinase domain against different inhibitor libraries and determined the co-structures of identified hits. We discovered that the ATP-binding pocket of CDK16 can accommodate both type I and type II kinase inhibitors. The most potent CDK16 inhibitors revealed by cell-free and cell-based assays were the multitargeted cancer drugs dabrafenib and rebastinib. An inactive DFG-out binding conformation was confirmed by the first crystal structures of CDK16 in separate complexes with the inhibitors indirubin E804 and rebastinib, respectively. The structures revealed considerable conformational plasticity, suggesting that the isolated CDK16 kinase domain was relatively unstable in the absence of a cyclin partner. The unusual structural features and chemical scaffolds identified here hold promise for the development of more selective CDK16 inhibitors and provide opportunity to better characterise the role of CDK16 and its related CDK family members in various physiological and pathological contexts.

Cyclin Y regulates the proliferation, migration, and invasion of ovarian cancer cells via Wnt signaling pathway. Tumour Biol. 2016;37:10161-10175. [PMID: 26831658 DOI: 10.1007/s13277-016-4818-3]

This study is designated to investigate the roles of cyclin Y (CCNY) and Wnt signaling pathway in regulating ovarian cancer (OC) cell proliferation, migration, and invasion. Quantitative real-time PCR (qRT-PCR), Western blot, MTT assay, cell scratch, and transwell test were used in our study, and transplanted tumor model was constructed on nude mice. C-Myc, cyclin D1, PFTK1, ki67, OGT, and β-catenin protein expressions in tumor tissues were detected. CCNY was significantly upregulated in OC cell lines and tissues (both P < 0.05); significant association was observed between CCNY expression and clinicopathological stage, lymph node metastasis (LNM) (P < 0.05); and the CCNY expression in stages III to IV was higher than that in stages I to II, and patients with LNM had higher CCNY expression when compared with those in patients without LNM (P < 0.05); expressions of c-Myc, cyclin D, PFTK1, ki67, and OGT were upregulated in OC tissues compared with ovarian benign tissues, suggesting that these expressions were significantly different between the two groups (P < 0.05); CCNY significantly exacerbated proliferation, migration, and invasion of A2780 cells; c-Myc and cyclin D1 protein expressions increased as the expression of CCNY increased (P < 0.001); β-catenin expressions in A2780 cells with over-expression of CCNY were significantly increased in the nucleus, but significantly decreased in the cytoplasm (both P < 0.05); high expressions of CCNY exacerbated the proliferation of A2780 cells in nude mice and significantly increased c-Myc, cyclin D1, PFTK1, ki67, and OGT protein expressions in tumor tissues which were transplanted into nude mice (P < 0.01). CCNY might exacerbate the proliferation, migration, and invasion of OC cells via activating the Wnt signaling pathway. Thus, this study provides a theoretical foundation for the development of therapeutic drugs that are able to cure OC by targeting CCNY.

PFTK1 regulates cell proliferation, migration and invasion in epithelial ovarian cancer

PFTK1, also named Cyclin-Dependent Kinase 14 (CDK14), is a member of the cell division cycle 2 (CDC2)-related protein kinase family. It is a serine/threonine-protein kinase involved in the regulation of cell cycle progression and cell proliferation. In this study, we investigated the role of PFTK1 in epithelial ovarian cancer (EOC) development. The expression of PFTK1 was detected by Western blot and immunohistochemistry staining, both of which demonstrated that PFTK1 was overexpressed in EOC tissues and cells. Statistical analysis showed the expression of PFTK1 was associated with multiple clinicopathological factors, including tumor grade, FIGO stage, lymph node metastatis, Ki-67 expression and predicted a poor prognosis of EOC patients. With in vitro studies we found that PFTK1 expression was decreased in serum-starved ovarian cancer cells, and progressively increased after serum-re-feeding. Knocking PFTK1 down by small interfering RNA (siRNA) significantly inhibited ovarian cancer cell proliferation, migration and invasion. Taken together, our study suggested that PFTK1 played an important role in ovarian cancer development.

PFTK1 Promotes Gastric Cancer Progression by Regulating Proliferation, Migration and Invasion

PFTK1, also known as PFTAIRE1, CDK14, is a novel member of Cdc2-related serine/threonine protein kinases. Recent studies show that PFTK1 is highly expressed in several malignant tumors such as hepatocellular carcinoma, esophageal cancer, breast cancer, and involved in regulation of cell cycle, tumors proliferation, migration, and invasion that further influence the prognosis of tumors. However, the expression and physiological significance of PFTK1 in gastric cancer remain unclear. In this study, we analyzed the expression and clinical significance of PFTK1 by Western blot in 8 paired fresh gastric cancer tissues, nontumorous gastric mucosal tissues and immunohistochemistry on 161 paraffinembedded slices. High PFTK1 expression was correlated with the tumor grade, lymph node invasion as well as Ki-67. Through Cell Counting Kit (CCK)-8 assay, flow cytometry, colony formation, wound healing and transwell assays, the vitro studies demonstrated that PFTK1 overexpression promoted proliferation, migration and invasion of gastric cancer cells, while PFTK1 knockdown led to the opposite results. Our findings for the first time supported that PFTK1 might play an important role in the regulation of gastric cancer proliferation, migration and would provide a novel promising therapeutic strategy against human gastric cancer.

Knockdown of PFTK1 Inhibits the Migration of Glioma Cells

The prognosis of glioma patients is generally poor, so it is urgent to find out the underlying molecular mechanisms. PFTK1 is a member of cyclin-dependent kinases (Cdks) family and has been reported to contribute to tumor migration and invasion. In this study, we aimed to explore the expression and function in human glioma. Western blot and immunohistochemistry were used to evaluate the expression of PFTK1. PFTK1 expression was higher in glioma tissues compared with normal brain tissues, and its level was associated with the WHO grade in Western blot analysis. The suppression of PFTK1 expression by RNA interference was shown to inhibit the migration of glioma cells. Knockdown of PFTK1 increases E-cadherin expression and decreases vimentin expression. These data show that PFTK1 may participate in the pathogenic process of glioma, suggesting that PFTK1 can become a potential therapeutic strategy for gastric cancer.

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

PFTK1 was a cell division cycle 2-related serine/threonine protein kinase, which was up-regulated in breast cancer tissues and breast cancer lines. And up-regulated PFTK1 was highly associated with grade, axillary lymph node status, and Ki-67. Moreover, Kaplan-Meier curve showed that up-regulated PFTK1 was related to the poor breast carcinoma patients' overall survival. Here, we first discovered and confirmed that cyclin B was a new interacting protein of PFTK1, and the complex might increase the amount of DVL2, which triggers Wnt/β-catenin signaling pathway. Furthermore, knockdown of PFTK1 attenuated cell proliferation, anchorage-independent cell growth, and cell migration and invasion by inhibiting the transcriptional activation of β-catenin for cyclin D1, MMP9, and HEF1, whereas exogenous expression of PFTK1 might promote MDA-MB-231 cells proliferation, migration, and invasion via promoting PFTK1-DVL2-β-catenin axis. Our findings supported the notion that up-regulated PFTK1 might promote breast cancer progression and metastasis by activating Wnt signaling pathway through the PFTK1-DVL2-β-catenin axis.

Targeting cyclin-dependent kinases in human cancers: from small molecules to Peptide inhibitors

Cyclin-dependent kinases (CDK/Cyclins) form a family of heterodimeric kinases that play central roles in regulation of cell cycle progression, transcription and other major biological processes including neuronal differentiation and metabolism. Constitutive or deregulated hyperactivity of these kinases due to amplification, overexpression or mutation of cyclins or CDK, contributes to proliferation of cancer cells, and aberrant activity of these kinases has been reported in a wide variety of human cancers. These kinases therefore constitute biomarkers of proliferation and attractive pharmacological targets for development of anticancer therapeutics. The structural features of several of these kinases have been elucidated and their molecular mechanisms of regulation characterized in depth, providing clues for development of drugs and inhibitors to disrupt their function. However, like most other kinases, they constitute a challenging class of therapeutic targets due to their highly conserved structural features and ATP-binding pocket. Notwithstanding, several classes of inhibitors have been discovered from natural sources, and small molecule derivatives have been synthesized through rational, structure-guided approaches or identified in high throughput screens. The larger part of these inhibitors target ATP pockets, but a growing number of peptides targeting protein/protein interfaces are being proposed, and a small number of compounds targeting allosteric sites have been reported.

Silencing stathmin-modulating efficiency of chemotherapy for esophageal squamous cell cancer with paclitaxel

Paclitaxel (PTX) is broadly considered the drug of choice for treating human esophageal squamous cell cancer (ESCC). However, PTX resistance often ultimately leads to treatment failure. stathmin, or Op18, is a ubiquitously expressed 19-kDa cytosolic phosphoprotein that can integrate various cellular regulatory signals. stathmin overexpression could lead to resistance to chemotherapeutic agents. In this study we investigated the effect of stathmin gene silencing, using small interfering RNA (stathmin siRNA), on the efficacy of PTX in ESCC. Transfection of stathmin siRNA could significantly inhibit stathmin mRNA and protein levels in ESCC cell lines EC9706 and Eca-109. The silencing of stathmin combined with PTX significantly inhibited the proliferation of EC9706 and Eca-109 cells, with a significantly higher proportion of cells at G2/M phase and this antiproliferative effect was accompanied by an increase in apoptosis rates and morphology changes of EC9706 and Eca-109. Thus, combined chemotherapeutic agent PTX and stathmin siRNA could potentially enhance the therapeutic outcomes of PTX in treating ESCC.

Spontaneous genomic alterations in a chimeric model of colorectal cancer enable metastasis and guide effective combinatorial therapy

Colon cancer is the second most common cause of cancer mortality in the Western world with metastasis commonly present at the time of diagnosis. Screening for propagation and metastatic behavior in a novel chimeric-mouse colon cancer model, driven by mutant p53 and β-Catenin, led to the identification of a unique, invasive adenocarcinoma. Comparison of the genome of this tumor, CB42, with genomes from non-propagating tumors by array CGH and sequencing revealed an amplicon on chromosome five containing CDK6 and CDK14, and a KRAS mutation, respectively. Single agent small molecule inhibition of either CDK6 or MEK, a kinase downstream of KRAS, led to tumor growth inhibition in vivo whereas combination therapy not only led to regression of the subcutaneous tumors, but also near complete inhibition of lung metastasis; thus, genomic analysis of this tumor led to effective, individualized treatment.

[The function and molecular mechnism of cyclin Y protein]

近年来，陆续有一些新的周期素蛋白被发现，细胞周期素Y（cyclin Y, CCNY）即为其中之一。现有的研究表明cyclinY高度保守，在调节细胞周期及转录过程中发挥重要作用，而且cyclin Y在多种肿瘤组织中高表达，在肿瘤增殖调控中可能发挥重要的功能。现就cyclin Y的研究进展及其与肿瘤的关系做一综述。

Deregulations in the cyclin-dependent kinase-9-related pathway in cancer: implications for drug discovery and development

The CDK9-related pathway is an important regulator of mammalian cell biology and is also involved in the replication cycle of several viruses, including the human immunodeficiency virus type 1. CDK9 is present in two isoforms termed CDK9-42 and CDK9-55 that bind noncovalently type T cyclins and cyclin K. This association forms a heterodimer, where CDK9 carries the enzymatic site and the cyclin partner functions as a regulatory subunit. This heterodimer is the main component of the positive transcription elongation factor b, which stabilizes RNA elongation via phosphorylation of the RNA pol II carboxyl terminal domain. Abnormal activities in the CDK9-related pathway were observed in human malignancies and cardiac hypertrophies. Thus, the elucidation of the CDK9 pathway deregulations may provide useful insights into the pathogenesis and progression of human malignancies, cardiac hypertrophy, AIDS and other viral-related maladies. These studies may lead to the improvement of kinase inhibitors for the treatment of the previously mentioned pathological conditions. This review describes the CDK9-related pathway deregulations in malignancies and the development of kinase inhibitors in cancer therapy, which can be classified into three categories: antagonists that block the ATP binding site of the catalytic domain, allosteric inhibitors, and small molecules that disrupt protein-protein interactions.