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

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer death worldwide. It is urgent to develop new drugs to improve the prognosis of ESCC patients. Here, we found benzydamine, a locally acting non-steroidal anti-inflammatory drug, had potent cytotoxic effect on ESCC cells. Benzydamine could suppress ESCC proliferation in vivo and in vitro. In terms of mechanism, CDK2 was identified as a target of benzydamine by molecular docking, pull-down assay and in vitro kinase assay. Specifically, benzydamine inhibited the growth of ESCC cells by inhibiting CDK2 activity and affecting downstream phosphorylation of MCM2, c-Myc and Rb, resulting in cell cycle arrest. Our study illustrates that benzydamine inhibits the growth of ESCC cells by downregulating the CDK2 pathway.
Humans ; Benzydamine ; Esophageal Neoplasms/drug therapy* ; Esophageal Squamous Cell Carcinoma/drug therapy* ; Molecular Docking Simulation ; Phosphorylation ; Cell Proliferation ; Cell Line, Tumor ; Apoptosis ; Cyclin-Dependent Kinase 2

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have led transformative breakthrough of clinical therapy for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER-2)-negative breast cancer patients. CDK4/6 inhibitors that have been marketed in China include Ribociclib, Palbociclib, Abemaciclib and Dalpiciclib. For HR-positive HER-2-negative locally advanced and metastatic breast cancer, CDK4/6 inhibitors combined with endocrine therapy have become standard regimen, which can prolong the survival of patients. In the adjuvant treatment stage of early breast cancer, CDK4/6 inhibitors have also achieved positive results and been approved for indications. At present, CDK4/6 inhibitors have been widely used in clinical practice in China. In order to further improve the standardized application of CDK4/6 inhibitors in China, the Breast Cancer Expert Committee of the National Center for Cancer Quality Control and the Professional Committee of Clinical Research of Cancer Drugs of the Chinese Anti-Cancer Association organized the related expert to update the consensus based on the "CDK4/6 inhibitor consensus on clinical application of in the treatment of hormone receptor positive human epidermal growth factor receptor 2 negative advanced breast cancer (2021 edition)" . The updated consensus systematically introduces the pharmacological characteristics, drug monitoring and adverse event management, etc., of CDK4/6 inhibitors to promote the accuracy of clinical decision-making with the ultimate goal to prolong the overall survival of patients and improve the quality of life.
Humans ; Female ; Breast Neoplasms/pathology* ; Quality of Life ; Consensus ; Triple Negative Breast Neoplasms/drug therapy* ; Receptor, ErbB-2/metabolism* ; Protein Kinase Inhibitors ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; Cyclin-Dependent Kinase 4/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

BACKGROUND: Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. METHODS: To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (Δψm) loss. CONCLUSION: Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.
Animals ; Apoptosis ; Blotting, Western ; Calcium-Transporting ATPases ; Cyclin-Dependent Kinase 5 ; Diabetes Mellitus, Type 2 ; Down-Regulation ; Endoplasmic Reticulum Stress ; Endoplasmic Reticulum ; Gene Expression ; Genes, Homeobox ; Glucose ; Hyperglycemia ; Insulin-Secreting Cells ; Membrane Potential, Mitochondrial ; Polymerase Chain Reaction ; Rats ; Reactive Oxygen Species ; Reticulum ; Reverse Transcription ; Up-Regulation

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

OBJECTIVETo investigate the antitumor effect of lycorine on renal cell carcinoma ACHN cells and explore the possible mechanism.

METHODSWe used flow cytometry to examine the effect of lycorine on ACHN cell cycle and apoptosis. The cell proliferation, migration and invasion were assessed with MTS assay, wound healing assay, and Transwell assay, respectively. Colony forming assay was performed, and the mRNA and protein levels of Bax, Bcl-2, survivin, caspase-3, cyclin D1 and CDK4 were measured with qRT-PCR and Western blotting.

RESULTSLycorine obviously inhibited the proliferation of ACHN cells with an IC(50) of 24.34 µmol/L. Lycorine also induced apoptosis of ACHN cells, caused cell cycle arrest at G(0)/G(1) phase, and suppressed the colony forming ability of the cells in a dose-dependent manner. The migration and invasion of ACHN cells were significantly inhibited by 5 µmol/L lycorine. Lycorine up-regulated the mRNA levels of CDK4, Bax, caspase-3 while down-regulated the levels of survivin, Bcl-2 and Cyclin D1; the protein levels of CDK4 and Bax were increased and cyclin D1, Bcl-2 and surviving expressions were decreased, but caspase-3 expression showed no significant changes following the treatment.

CONCLUSIONLycorine has obvious antitumor effect against ACHN cells, suggesting its value as a new therapeutic agent for renal cell carcinoma.

Amaryllidaceae Alkaloids ; pharmacology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; Carcinoma, Renal Cell ; pathology ; Caspase 3 ; metabolism ; Cell Cycle Checkpoints ; Cell Line, Tumor ; drug effects ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Humans ; Inhibitor of Apoptosis Proteins ; metabolism ; Phenanthridines ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo evaluate the effect of Foxo3a gene over-expression on the development of rat ovarian granulosa cells and in prevention of cisplatin-induced ovarian damage in rats.

METHODSRat ovarian granulose cells released mechanically from the ovaries were cultured in vitro and identified with HE staining and immunohistochemical staining for FSHR. A recombinant adenovirus carrying Foxo3a gene was constructed for infecting the granulose cells, and the cell growth and expressions of cyclin D1, p27, Bax, and Bim were detected; the cell apoptosis and cell cycle changes were detected using Hoechst/PI 33342 staining and flow cytometry, respectively. The transfected cells were challenged with cisplatin and the cell apoptosis was detected with flow cytometry.

RESULTSOver 90% of the cultured cells survived and contained more than 95% ovarian granulose cells. Infection of the cells with the recombinant adenovirus resulted in over-expressions of Foxo3a at the mRNA and protein levels at 36 h and 48 h after the infection, respectively. The infected cells showed suppressed proliferation, increased apoptotic rate and cell cycle arrest in G1 phase with increased expressions of Bim, p27, and cyclin D1 but without significant changes in Bax expression. Cisplatin exposure caused a significantly higher apoptosis rate in the infected cells than in the control cells.

CONCLUSIONOver-expression of Foxo3a gene can promote granulose cell apoptosis by increasing Bim expression and cause cell cycle arrest in G1 phase by increasing cyclin D1 and p27 expressions, but can not prevent the toxic effects of cisplatin on ovarian granulosa cells.

Animals ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Bcl-2-Like Protein 11 ; Cell Cycle Checkpoints ; Cell Proliferation ; Cells, Cultured ; Cisplatin ; adverse effects ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Female ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression ; Granulosa Cells ; cytology ; drug effects ; Membrane Proteins ; metabolism ; Proto-Oncogene Proteins ; metabolism ; Rats ; Transfection ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate the expression of p16INK4a protein in breast cancer and analyze its clinical significance.

METHODSA total of 132 surgical specimens of primary breast cancer obtained between 2014 and 2015 were examined for expressions of ER, PR, CK5/6, Her-2 and p16INK4a proteins using immunohistochemistry.

RESULTSThe breast cancer samples were classified into 5 molecular subtypes, namely Luminal A (58 cases), Luminal B (32 cases), Her-2-positive (21 cases), basal-like (12 cases) and normal-like (9 cases) types. p16INK4a expression was negative in 7/132 (5.30%) cases, weakly positive in 15/132 (11.36%) cases, positive in 40/132 (30.30%) cases, and strongly positive in 70/132 (53.03%) cases. When categorizing negative and weakly positive cases into negative group and the positive and strongly positive cases into positive group, the total negative and positive expression rates of p16INK4a were 16.67% (22/132) and 83.33% (110/132) in the carcinoma tissues. Statistical analysis showed the expression intensity of p16INK4a differed significantly between the age groups (P<0.05) but was not significantly correlated with ER, PR, Her-2, molecular subtypes or metastasis of the tumors.

CONCLUSIONThe compensatory high expression of p16INK4a is the main mechanism of cell cycle deregulation in invasive breast cancer and can be an important specific molecular marker for invasive breast cancer.

Biomarkers, Tumor ; metabolism ; Breast Neoplasms ; classification ; diagnosis ; metabolism ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Female ; Humans ; Keratin-5 ; metabolism ; Keratin-6 ; metabolism ; Receptor, ErbB-2 ; metabolism ; Receptors, Estrogen ; metabolism ; Receptors, Progesterone ; metabolism

OBJECTIVETo study the effects of LIF combined with bFGF on the proliferation, stemness and senescence of hUC-MSC.

METHODSExperiments were divided into 4 groups: control group, in which the cells were treated with complete medium (α-MEM containing 10% FBS); group LIF, in which the cells were treated with complete medium containing 10 ng/ml LIF; group bFGF, in which the cells were treated with complete medium containing 10 ng/ml bFGF; combination group, in which the cells were treated with complete medium containing 10 ng/ml LIF and 10 ng/ml bFGF. The growth curves of hUC-MSC at passage 4 in different groups were assayed by cell counting kit 8. Cellular morphologic changes were observed under inverted phase contrast microscope; hUC-MSC senescence in different groups was detected by β-galactosidase staining. The expression of PCNA, P16, P21, P53, OCT4 and NANOG genes was detected by RT-PCR.

RESULTSThe cell growth curves of each group were similar to the S-shape; the cell proliferation rate from high to low as follows: that in the combination group > group bFGF > group LIF > control group. Senescence and declining of proliferation were observed at hUC-MSC very early in control group; the cells in group LIF maintained good cellular morphology at early stage, but cell proliferation was slow and late senescence was observed; a few cells in group bFGF presented signs of senescence, but with quick proliferation; the cells in combination group grew quickly and maintained cellular morphology of hUC-MSC for long time. The LIF and bFGF up-regulated the expression of PCNA, OCT4 and NANOG, while they down-regulated the expression of P16, P21, P53, and their combinative effects were more significant.

CONCLUSIONLIF combined with bFGF not only can promote the proliferation and maintenance of stemness of hUC-MSC, but also can delay the senescence of hUC-MSC.

Cell Cycle ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Fibroblast Growth Factor 2 ; pharmacology ; Genes, Homeobox ; Humans ; Leukemia Inhibitory Factor ; pharmacology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Octamer Transcription Factor-3 ; metabolism ; Organic Chemicals ; Proliferating Cell Nuclear Antigen ; metabolism ; Tumor Suppressor Protein p53 ; metabolism ; Umbilical Cord ; cytology