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

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 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

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

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

OBJECTIVETo study the effect of down-regulation of histone deacetylase 2 (HDAC2) expression on cell proliferation and cell cycle in cervical carcinoma cell lines HeLa.

METHODSHDAC2 siRNA and control siRNA were transfected to HeLa cells. CCK-8 and flow cytometry were used to analyze the changes of cell proliferation and cell cycle, respectively. Western blot was employed to detect the changes of cell proliferation and cell cycle-related proteins.

RESULTSHDAC2 siRNA significantly down-regulated the expression of HDAC2 protein in HeLa cells, resulting in marked inhibition of cell proliferation. In addition, the percentage of cells in G(0)/G(1) phase in HDAC2 siRNA group (63.3% ± 2.0%) was significantly higher than that in untreated group (29.3% ± 1.7%) or control siRNA group (29.4% ± 1.7%), F = 354.181, P = 0.000. Furthermore, Western blot demonstrated that down-regulation of HDAC2 expression decreased the expression of cyclin D1, cyclin E and CDK2 proteins but increased the expression of p21 protein.

CONCLUSIONSDown-regulation of HDAC2 expression mediates proliferation inhibition and cell cycle arrest. It is associated with decrease in cyclin D1, cyclin E and CDK2 protein expression and increase in p21 protein expression.

Cell Cycle ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin E ; metabolism ; Cyclin-Dependent Kinase 2 ; metabolism ; Down-Regulation ; HeLa Cells ; Histone Deacetylase 2 ; genetics ; metabolism ; Humans ; Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins p21(ras) ; metabolism ; RNA, Small Interfering ; genetics ; Transfection

Sphingosine kinase 1 (SphK1) plays critical roles in cell biological functions. Here we investigated the effects of SphK1 inhibitor SKI II on hepatoma HepG2 cell cycle progression and invasion. Cell survival was determined by SRB assay, cell cycle progression was assayed by flow cytometry, the ability of cell invasion was measured by Matrigel-Transwell assay and protein expression was detected by Western blotting. The results showed that SKI II markedly inhibited HepG2 cell survival in a dose-dependent manner, induced G1 phase arrest in HepG2 cell and inhibited cell invasion. SKI II markedly decreased the expressions of G1-phase-related proteins CDK2, CDK4 and Cdc2 and the levels of cell invasion-associated proteins MMP2 and MMP9. The results showed that SKI II inhibited cell cycle progression and cell invasion, implying SphK1 as a potential target for hepatoma treatment.
CDC2 Protein Kinase ; Cell Movement ; drug effects ; Cell Survival ; drug effects ; Cyclin-Dependent Kinase 2 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Cyclin-Dependent Kinases ; metabolism ; G1 Phase ; drug effects ; Hep G2 Cells ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Phosphotransferases (Alcohol Group Acceptor) ; antagonists & inhibitors ; Thiazoles ; pharmacology

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

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.
Animals ; Animals, Newborn ; Biomarkers ; metabolism ; Cell Proliferation ; genetics ; Cyclin-Dependent Kinase 2 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p57 ; genetics ; metabolism ; Cyclins ; genetics ; metabolism ; Gene Expression Regulation ; Hippocampus ; cytology ; metabolism ; Ki-67 Antigen ; genetics ; metabolism ; Magnetic Fields ; MicroRNAs ; genetics ; metabolism ; Neural Stem Cells ; cytology ; metabolism ; Primary Cell Culture ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

OBJECTIVETo explore the influence of different nutritional support routes on the intestinal mucosal epithelial cell cycle in burned rats.

METHODSSixty-six Wistar rats inflicted with 30% TBSA III degree burns on the back were employed as the model and were randomly divided into enteral feeding group (EF) and intravenously parenteral nutrition group (PN). Equal volume of nutritional support fluid containing predetermined equal amount of calories and nitrogen was applied via feeding or intravenously infusion through external jugular vein. The indices were observed on 6, 12, 24, 48 and 72 postburn hours (PBHs) with the reference to those in 6 normal rats. The intestinal epithelial cell cycle in jejunal and ileal mucous membrane was analyzed by flow cytometry. Western blotting method was employed in the examination of the expression of cyclin D1, E and that of cyclin dependent kinase (CDK)2 and CDK4.

RESULTS(1) lntestinal mucosal epithelial G0/G1 ratio in jejunum in EF group was significantly lower than that in PN group at 72 PBHs (P < 0.05). While the ratio in ileum in EF was obviously higher than that in PN groups at 6, 12, 48 and 72 PBHs (P < 0.05). (2) The cell percentage of S phase in EF group was evidently higher than that in PN group (P < 0.05 - 0.01) at 48 and 72 PBHs. (3) Intestinal mucosal cyclin D1 expression increased significantly in EF group at 24 PBHs and in PN group at 48 PBHs (P < 0.05) and which in EF group was obviously higher than that in PN group at 72 PBHs (P < 0.05). (4) The expression of the intestinal mucosal cyclin E in EF group at 72 PBHs was evidently higher than the control value and that in PN group (P < 0.05). (5) The expression of CDK2 exhibited no obvious difference among PN,EF and control group (P < 0.05). The CDK4 expression in EF group increased obviously at 72 PBHs (P < 0.05).

CONCLUSIONEarly postburn enteral feeding was beneficial to the progression of intestinal mucosal epithelial cell cycle and to the repairing and renovation of injured intestinal mucosal membrane. Cyclin and CDK might be important in the modulation of the intestinal mucosal epithelial cell cycle.

Animals ; Burns ; metabolism ; pathology ; CDC2-CDC28 Kinases ; Cell Cycle ; physiology ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 2 ; Cyclin-Dependent Kinase 4 ; Cyclin-Dependent Kinases ; metabolism ; Disease Models, Animal ; Enteral Nutrition ; Female ; G1 Phase ; physiology ; Intestinal Mucosa ; metabolism ; pathology ; Male ; Protein-Serine-Threonine Kinases ; metabolism ; Proto-Oncogene Proteins ; Rats ; Rats, Wistar ; Resting Phase, Cell Cycle ; physiology ; S Phase ; physiology