OBJECTIVETo investigate the expressions of cyclin E, cyclin dependent kinase 2 (CDK-2) and cyclin-dependent kinase inhibitor p57(KIP2) in human gastric cancer, and to evaluate the relationships between protein levels and clinicopathological parameters.

METHODSWestern blot was used to measure the expressions of cyclin E, CDK-2 and p57(KIP2) proteins in the surgically resected gastric carcinoma, adjacent normal mucosa and metastatic lymph nodes from 36 patients.

RESULTSCyclin E and CDK-2 protein levels were higher in gastric cancer tissues in comparison with normal tissues (P < 0.05). Overexpression of cyclin E was correlated with lymph node involvement, poor histological grade and serosa invasion (P < 0.05). Overexpression of CDK-2 was correlated with lymph nodes involvement (P < 0.05). No statistically significant difference between cyclin E and CDK-2 expression was found when samples were stratified according to tumor size (P > 0.05). Expression of cyclin E and CDK-2 showed a positive linear correlation (r = 0.451, P = 0.01). Protein levels of p57(KIP2) were lower in gastric cancer tissues than in the normal mucosa (P < 0.05). Decreased expression of p57(KIP2) was correlated with lymph node involvement (P < 0.05). No statistically significant difference in p57(KIP2) expression was found when sample were stratified according to tumor size, histological grade or serosa invasion (P > 0.05). In metastatic lymph nodes, expression of cyclin E was increased and the expression of p57(KIP2) decreased.

CONCLUSIONOverexpressions of cyclin E, CDK-2 and downregulated expression of p57(KIP2) may play important roles in tumorigenesis and metastatic potential of gastric cancer.

Blotting, Western ; CDC2-CDC28 Kinases ; Cyclin E ; analysis ; physiology ; Cyclin-Dependent Kinase 2 ; Cyclin-Dependent Kinase Inhibitor p57 ; Cyclin-Dependent Kinases ; analysis ; physiology ; Humans ; Lymphatic Metastasis ; Nuclear Proteins ; analysis ; physiology ; Protein-Serine-Threonine Kinases ; analysis ; physiology ; Stomach Neoplasms ; chemistry ; pathology

Glioblastoma is a common brain tumor and the overall survival rate of the patients is very low, so it is an effective way to develop the potential chemotherapy or adjuvant chemotherapy drugs in glioblastoma treatment. As a well-known antimalarial drug, artesunate(ARTs) has clear side effects, and recently it has been reported to have antitumor effects, but rarely reported in glioblastoma. Different concentrations of ARTs were used to treat the glioblastoma cells, and then the inhibitory effect of ARTs on glioblastoma proliferation was detected by MTT assay; Ki67 immunofluorescence assay was used to detect the proliferation of cells; Soft agar experiment was used to explain the clonal formation abilities ; Flow Cytometry was used to detect the cell cycle; and Western blot assay was used to determine the expression of key cell cycle protein. MTT assay results indicated that ARTs-treated glioblastoma cell A172, U251, U87 were significantly inhibited in a time-and-dose dependent manner as compared to the control group(DMSO treatment group). Soft agar experiment showed that ARTs could significantly reduce the clonal formation ability of glioblastoma. Furthermore, Flow cytometry analysis showed that ARTs could obviously increase the cell proportion in G₀/G₁ phase and reduce the cell proportion in S phase. Western blot results showed that the expressions of cell cycle-related proteins CDK2, CDK4, cyclin D1 and cyclin B1 were all obviously down-regulated. Above all, ARTs may inhibit the proliferation of glioblastoma cells by arresting cell cycle in G₀/G₁ phase through down-regulating the expression of CDK2, CDK4, cyclin D1, cyclin B1. These results may not only provide a novel method for rediscovering and reusing ARTs but also provide a new potential drug for treating glioblastoma.
Antineoplastic Agents ; pharmacology ; Apoptosis ; Artesunate ; pharmacology ; Cell Cycle Checkpoints ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin B1 ; metabolism ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Glioblastoma ; drug therapy ; pathology ; Humans

Carcinoma of the uterine cervix is one of the most common malignancies among women worldwide. Human papillomaviruses (HPV) have been identified as the major etiological factor in cervical carcinogenesis. However, the time lag between HPV infection and the diagnosis of cancer indicates that multiple steps, as well as multiple factors, may be necessary for the development of cervical cancer. The development and progression of cervical carcinoma have been shown to be dependent on various genetic and epigenetic events, especially alterations in the cell cycle checkpoint machinery. In mammalian cells, control of the cell cycle is regulated by the activity of cyclin-dependent kinases (CDKs) and their essential activating coenzymes, the cyclins. Generally, CDKs, cyclins, and CDK inhibitors function within several pathways, including the p16INK4A-cyclin D1-CDK4/6-pRb-E2F, p21WAF1-p27KIP1-cyclinE-CDK2, and p14ARF-MDM2-p53 pathways. The results from several studies showed aberrant regulation of several cell cycle proteins, such as cyclin D, cyclin E, p16 INK4A, p21WAF1, and p27KIP1, as characteristic features of HPV- infected and HPV E6/E7 oncogene-expressing cervical carcinomas and their precursors. These data suggested further that interactions of viral proteins with host cellular proteins, particularly cell cycle proteins, are involved in the activation or repression of cell cycle progression in cervical carcinogenesis.
Uterine Cervical Neoplasms/*pathology ; Tumor Suppressor Protein p53/physiology ; Tumor Suppressor Protein p14ARF/physiology ; Retinoblastoma Protein/physiology ; Proto-Oncogene Proteins c-mdm2/physiology ; Humans ; Female ; E2F Transcription Factors/physiology ; Cyclin-Dependent Kinase Inhibitor p27/physiology ; Cyclin-Dependent Kinase Inhibitor p21/physiology ; Cyclin-Dependent Kinase Inhibitor p16/physiology ; Cyclin-Dependent Kinase 4/physiology ; Cyclin-Dependent Kinase 2/physiology ; Cyclin E/physiology ; Cyclin D1/physiology ; Cell Cycle/*physiology

Cell cycle plays a crucial role in cell development. Cell cycle progression is mainly regulated by cyclin dependent kinase (CDK), cyclin and endogenous CDK inhibitor (CKI). Among these, CDK is the main cell cycle regulator, binding to cyclin to form the cyclin-CDK complex, which phosphorylates hundreds of substrates and regulates interphase and mitotic progression. Abnormal activity of various cell cycle proteins can cause uncontrolled proliferation of cancer cells, which leads to cancer development. Therefore, understanding the changes in CDK activity, cyclin-CDK assembly and the role of CDK inhibitors will help to understand the underlying regulatory processes in cell cycle progression, as well as provide a basis for the treatment of cancer and disease and the development of CDK inhibitor-based therapeutic agents. This review focuses on the key events of CDK activation or inactivation, and summarizes the regulatory processes of cyclin-CDK at specific times and locations, as well as the progress of research on relevant CDK inhibitor therapeutics in cancer and disease. The review concludes with a brief description of the current challenges of the cell cycle process, with the aim to provide scientific references and new ideas for further research on cell cycle process.
Cyclin-Dependent Kinases/metabolism* ; Cyclins/metabolism* ; Protein Serine-Threonine Kinases ; Cell Cycle Proteins/metabolism* ; Cell Cycle/physiology* ; Cyclin-Dependent Kinase 2

This study was aimed to investigate the effect of arsenic trioxide (As2O3) on proliferation and cell cycle of human Burkitt lymphoma cells and its related molecular mechanism, so as to provide experimental evidence for treatment of Burkitt lymphoma with As2O3. Human Burkitt lymphoma cell line Namalwa was used as the model, the effect of As2O3 on cell proliferation, cell cycle and apoptosis, as well as the expression of cell cycle modulation related genes, including mRNA and protein level, were detected by MTT method, flow cytometry, real-time quantitative PCR (RQ-PCR) and Western blot, respectively. The results showed that the As2O3 inhibited significantly the growth and proliferation of Namalwa cells in concentration-and time-dependent manner. The As2O3 arrested obviously cell cycle of Namalwa cells in G1 phase, and showed significant concentration-effect relationship. The As2O3 induced the apoptosis of Namalwa cells in concentration-and time-dependent manner, downregulated the expression of the important driving genes of cell cycle including Cyclin E and CDK2 in mRNA and protein level, upregulated the expression of the important inhibiting gene of cell cycle-P21 in mRNA and protein level in concentration-dependent manner. It is concluded that As2O3 inhibits significantly the growth and proliferation of Namalwa cells, and the effect was closely relates with its inducing the apoptosis and blocking the cell cycle of Namalwa. The action of blocking cell cycle is closely associated with its downregulating the expression of driving genes of cell cycle-Cyclin E and CDK2, upregulating the expression of the inhibiting gene of cell cycle-P21.
Apoptosis ; Arsenicals ; pharmacology ; Burkitt Lymphoma ; pathology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin E ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Humans ; Oncogene Proteins ; metabolism ; Oxides ; pharmacology

This study is to examine the effects of NNIspm-mediated cellular senescence of HepG2 cells and elucidate its potential molecular mechanism. Cellular senescence was detected with senescence-associated beta-galactosidase staining. Cell cycle distribution, intracellular fluorescence intensity and accumulation of intracellular reactive oxygen species (ROS) were detected by high content screening (HCS). Protein expression was detected by Western blotting. Polyamines content was analyzed by high performance liquid chromatography (HPLC). The results demonstrated that NNIspm significantly induced HepG2 cells senescence. This effect was due to the decrease of intracellular polyamines, the arrest at G0/G1 phase and an increase of ROS level. The molecular senescence marker p21 increased significantly after NNIspm treatment. In contrast, the protein expressions of Cyclin E and CDK2 were obvious down-regulation. The results indicated that cellular senescence induced by NNIspm was one of its antitumor mechanisms.
Antineoplastic Agents ; metabolism ; pharmacology ; Cellular Senescence ; drug effects ; Cyclin E ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; G1 Phase ; Hep G2 Cells ; Humans ; Oncogene Proteins ; metabolism ; Polyamines ; metabolism ; pharmacology ; Reactive Oxygen Species ; metabolism

The introduction of cyclin-dependent kinase (CDK) 4/6 inhibitors has revolutionized the clinical management paradigm of hormone receptor (HR) positive/human epidermal growth factor receptor (HER) 2 negative breast cancer. As of today, CDK 4/6 inhibitors including Palbociclib, Ribociclib, and Abemaciclib have been widely approved by regulatory agencies. Randomized clinical trials demonstrated that CDK 4/6 inhibitors in combination with an aromatase inhibitor (AI) or fulvestrant in the first-, second- or later-line setting for HR positive/HER2 negative locally advanced or metastatic breast cancer led to substantial reduction in the risk of disease progression or death. Adverse effects of treatment were manageable and as or better than expected in terms of patient satisfaction. Considering CDK4/6 inhibitors in combination with endocrine therapy being a novel approach in China clinical practice, the panel developed the consensus comprehensively describing the pharmacology properties, monitoring strategy during treatment and adverse events management, to facilitate greater understanding in Chinese oncologists of a whole new therapeutic class of drug, promote accuracy of clinical decision and help reach the ultimate goal of improving survival and quality of life of the target patient population.
Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; Breast Neoplasms/drug therapy* ; China ; Consensus ; Cyclin-Dependent Kinase 4 ; Cyclin-Dependent Kinase 6 ; Humans ; Protein Kinase Inhibitors/therapeutic use* ; Quality of Life ; Receptor, ErbB-2

Cyclin-dependent protein kinase (CDK) plays an important role in the replication of herpes simplex virus (HSV) and other important human disease viruses. But which kinds of CDK are required in the replication of HSV is still not clear. In this study, we infected dominant negative CDK2 cell line with different multiplicity of infection (MOI) of HSV-1-KOS strain (abbreviated as HSV below), and the results showed that the yield of HSV depended on the MOI; the replication of HSV delayed about 3 h as compared with that of the control in the one-step growth curve replication experiments; the CDK2 activity was induced 6 h post HSV infection and reached the highest 9 h post infection; the HSV went into rapid productive replication after the CDK2 was induced. We propose herein that the CDK2 is required in the initiation of replication of HSV.
Animals ; Cell Proliferation ; Cercopithecus aethiops ; Cyclin-Dependent Kinase 2 ; physiology ; HT29 Cells ; Humans ; Simplexvirus ; physiology ; Vero Cells ; Virus Replication

OBJECTIVETo observe the effects of Qufengtongluo Recipe (QFTLR) on the expressions of cell cycle regulatory proteins in rat mesangial cells (MCs) in vitro and investigate the mechanism by which QFTLR inhibits MC proliferation.

METHODSUsing the methods of serum pharmacology, we studied the expressions of cell cycle regulatory proteins in rat MCs treated with QFTLR by laser scanning confocal microscope and immunohistochemistry.

RESULTSCompared with the normal control cells, the cells challenged with lipopolysaccharide (LPS) showed significantly enhanced expressions of cyclin D1, CDK2, and P21 (P<0.01) and obviously lowered protein expression of P27 (P<0.01). Treatment of the LPS-challenged cells with QFTLR and benazepril both resulted in significantly attenuated expressions of cyclin D1, CDK2, and P21 and obvious increase of P27 expression (P<0.05 or P<0.01), but QFTLR produced stronger effects than benazepril in regulating of cyclinD1, P21 and P27 protein expressions (P<0.05 or P<0.01).

CONCLUSIONQFTLR inhibits rat MC proliferation in vitro possibly by down-regulating the cellular expressions of cyclin D1, CDK2, and P21 and up-regulating the expression of P27 protein.

Animals ; Cell Line ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Regulation ; drug effects ; Mesangial Cells ; cytology ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the correlation between cyclin-dependent kinase inhibitor p27kip1 and trastuzumab-resistance in gastric cancer.
 METHODS: We selected HER2-overexpressed human gastric cancer cell line NCI-N87 to establish trastuzumab-resistant NCI-N87/TR cell line by stepwise exposure to different doses of trastuzumab. The 50% inhibitory concentration (IC(50)) of trastuzumab and resistance index (RI) were calculated or analyzed by MTT assay. The expression levels of cdk2 and p27kip1 were detected by Western blot. After the treatment with cdk2 inhibitor (Purvalanol A), the expression levels of relevant proteins in NCI-N87/TR cells were detected by Western blot, and the sensitivity to trastuzumab was analyzed by MTT assay. 
 RESULTS: Compared with NCI-N87 cells, the expression of cdk2 was significantly increased in NCI-N87/TR cells (P<0.001), while the expression of p27kip1 showed a significant decrease (P<0.001). Restoration of the p27kip1 protein expression by cdk2 inhibitor (Purvalanol A) increased the sensitivity of NCI-N87/TR to trastuzumab.
 CONCLUSION Down-regulation of p27kip1 might be a mechanism for triggering trastuzumab resistance to gastric cancer cell line NCI-N87.
Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cyclin-Dependent Kinase 2 ; antagonists & inhibitors ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; genetics ; metabolism ; Drug Resistance, Neoplasm ; Humans ; Purines ; pharmacology ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Trastuzumab ; pharmacology