OBJECTIVETo investigate the effect of Oviductus Ranae (OR) on the expressions of CyclinD1, CDK6 and P15 in the liver of aged male rats.

METHODSEighteen male SD rats were randomly divided into 3 equal groups, namely the OR group, VE group and ageing model group. The rats received subcutaneous injection of D-galactose for 6 weeks to establish the aging models, and another 6 rats were injected daily with normal saline (NS) to serve as the normal control group. From the third week of the experiment, the rats were given oral OR or Vitamin E (VE) accordingly till the sixth week. After completion of the drug administration, all the rats were sacrificed for detecting the expressions of CyclinD1, CDK6 and P15 in the liver tissue by Western blotting.

RESULTSThe relative expression levels of CyclinD1, CDK6 and P15 in the liver of the rats in the OR group were 41.73-/+0.54, 23.29-/+0.30 and 1.49-/+0.30, respectively, significantly up-regulated as compared with those in the ageing model group (P<0.01). The expressions of the proteins were obviously down-regulated in the model group in comparison with those in the normal control group.

CONCLUSIONSOR treatment can lower the expressions of Cyclin D1 and CDK6 in the liver to enhance the liver cell proliferation in aged male rats. OR also promotes the expression of P15 through a feedback mechanism to prevent excessive proliferation of the cells. The effect of OR against ageing is mediated possibly by up-regulation of the proteins associated with the cell proliferation in the liver, a mechanism different from that of VE.

Aging ; metabolism ; Animals ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 6 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p15 ; metabolism ; Liver ; metabolism ; Male ; Materia Medica ; pharmacology ; Rats

The development and progression of most cancers have been well recognized as the result of highly activated cell cycle. Cyclin dependent kinase 4/6 plays important roles not only in mitosis, but also in multiple biological processes that contribute to cancer development, such as aging, apoptosis and histone modification. Three FDA approved CDK4/6 inhibitors, Palbociclib, Ribociclib and Abemaciclib, have been used as targeted cancer therapeutic agents to benefit patients with endocrine therapy-resistant breast cancer and other types of cancer, prolonging their survival. However, the clinical application of these inhibitors also leads to acquired drug resistance and other problems. This paper reviews the regulatory roles of CDK4/6, the application of CDK4/6 inhibitors in cancer and the challenge of drug resistance.
Breast Neoplasms ; Cyclin-Dependent Kinase 4/therapeutic use* ; Cyclin-Dependent Kinase 6/therapeutic use* ; Female ; Humans ; Molecular Targeted Therapy ; Protein Kinase Inhibitors/therapeutic use* ; Signal Transduction

OBJECTIVETo explore the expression level of microRNA-26a and its target gene CDK6 in extranodal NK/T-cell lymphoma (ENKTCL) and their possible role in genesis and development of ENKTCL.

METHODSReal time fluorescent quantitative PCR was used to detect the expression level of miR-26a in tissue of 15 patients with ENKTCL and 10 samples of normal NK cells. Maxvision immunohistochemistry technique was used to detect the expression level of CDK6 and miR-26a in tissue of 20 ENKTCL cases, 10 cases of proliferative lymphadenitis and 10 samples of normal lymph node, respectively. The possible role of miR-26a and its target gene CDK6 in genesis and development of ENKTCL were analyzed according to the clinical features of ENKTCL patients.

RESULTSThe expression of miR-26a was significantly lower in ENKTCL than that in normal NK cells. The expression of CDK6 was significantly higher in ENKTCL group than that in group proliferative lymphadenitis and normal lymph node. Correlation analysis showed that there was significant negative correlation between miR-26a expression and CDK6 expression (r = -0.54, P = 0.04). Meanwhile, there were no correlation of miR-26a expression with age, sex, Ann Arbor stage, LDH level, B symptoms and IPI. Although, there were no correlation of CDK6 expression with age, sex, LDH level and B symptoms, there were positive correlation of CDK6 expression with Ann Arbor stage and IPI.

CONCLUSIONthat abnormal expression of miR-26a may participate in genesis and development of ENKTCL through regulating the expression of its target gene CDK6.

Cyclin-Dependent Kinase 6 ; Humans ; Lymphoma, Extranodal NK-T-Cell ; MicroRNAs ; Real-Time Polymerase Chain Reaction

BACKGROUND/AIMS: Eukaryotic cell cycle is regulated by signal transduction pathways mediated by complexes of cyclin dependent kinases (CDKs) and their partner cyclins, or by interaction with CDK inhibitors. Thioacetamide (TA) is a weak hepatocarcinogen causing several types of liver damage in a dose dependent manner and ultimately producing malignant transformation. We investigated alterations of expression of cell cycle regulators in the rat liver, involved in G1 entry and progression during TA administration. METHODS: We studied expression patterns of cyclin D1, CDK4, CDK6, p21(CIP1) and p16(INK4a) during daily intraperitoneal injection of low dose TA (50 mg/kg) till 7 day. We used western blot and immunohistochemistry for detection. RESULTS: Expression of cyclin D1, CDK4, CDK6 and p21(CIP1) increased from 6 hour and peaked at 2, 3 day, then decreased next 2 days, and re-increased at 6 day. Cytoplasmo-nuclear translocation of cyclin D1 and p21(CIP1) was evident within 1 day and prominent at 2 and 7 day. Expression of p16(INK4a) increased immediately after TA treatment and remarkably increased from 3 day and progressed till 7 day, showing cytoplasmic location, suggestive of inactive form. Most of in situ immunoreactions occurred at the centrilobular hepatocytes. Concomitant nuclear translocation of p21(CIP1) and cyclin D1, different with p16(INK4a) suggests that p21(CIP1) might be a transporter for nuclear translocation rather than cell cycle inhibitor. CONCLUSIONS: Daily administration of low dose TA makes cell cycle open and G1 progress, possibly due to cyclin D1, CDK4 and CDK 6, their transporter p21(CIP1), and inactive p16(INK4a), which occur at quiescent hepatocytes, not stem cells.
Animals ; Cell Cycle Proteins/*metabolism ; Cyclin D1/metabolism ; Cyclin-Dependent Kinase 4/metabolism ; Cyclin-Dependent Kinase 6/metabolism ; Cyclin-Dependent Kinase Inhibitor p16/metabolism ; Cyclin-Dependent Kinase Inhibitor p21/metabolism ; G1 Phase ; Immunohistochemistry ; Liver/*drug effects/enzymology/metabolism ; Liver Diseases/chemically induced/metabolism/pathology ; Male ; Rats ; Rats, Sprague-Dawley ; Thioacetamide/*toxicity

Objective To prepare and identify rabbit anti-cyclin dependent kinase 6 (CDK6) antibody. Methods The recombinant pET21a (+)/CDK6 was successfully constructed, then the recombinant plasmid was transformed into E.coli BL21 (DE3) competent cells and was induced by isopropyl-β-D-thiogalactopyranoside (IPTG) for protein expression, which was detected by SDS-PAGE and Western blot analysis. The expressed protein was purified by nickel-chelating nitrilotriacetic acid (Ni-NTA) agarose and then analyzed by SDS-PAGE. Japanese white rabbits were immunized with purified CDK6 protein for many times every two weeks. The blood was collected at 0, 2, 4 and 6 weeks after immunization, and serum was separated from blood. The titer was detected by indirect ELISA. Western blot analysis, immunofluorescence assay and immunohistochemistry were employed to determine the specificity. Results High purity CDK6 protein and high specificity of rabbit anti-CDK6 antibody were successfully prepared. The titer of CDK6 rabbit serum antibody reached 1:30 000 after immunization, which could specifically recognize the CDK6 protein expressed in cervical cancer cell line and cervical cancer tissues. Conclusion The high titer and specificity of rabbit anti-CDK6 antibody is successfully prepared.
Animals ; Female ; Humans ; Rabbits ; Antibodies ; Antibody Specificity ; Blotting, Western ; Cyclin-Dependent Kinase 6 ; Enzyme-Linked Immunosorbent Assay ; Uterine Cervical Neoplasms

OBJECTIVETo explore the expression of CDK6 in nasopharyngeal carcinoma (NPC) and explore its clinical significance.

METHODSImmunohistochemistry was used to examine the differential expression of CDK6 protein in 101 NPC and 30 nasopharyngeal tissues, and the correlation of CDK6 expression with the clinical characteristics was analyzed in NPC cases.

RESULTSImmunohistochemistry demonstrated that CDK6 protein was a co-expressed factor in the cytoplasm and cell nuclei. CDK6 was expressed predominantly in the cytoplasm in nasopharyngeal tissues, but in NPC tissues, CDK6 was co-expressed predominantly in the cytoplasm and nuclei. Compared to the nasopharyngeal tissues, NPC tissues showed significantly up-regulated CDK6 expression (P=0.009) in positive correlation with tumor size (P=0.020) and clinical stages (P=0.0039).

CONCLUSIONSIncreased CDK6 protein expression is an unfavorable factor that promotes the development and progression of NPC.

Carcinoma ; Cell Nucleus ; Cyclin-Dependent Kinase 6 ; metabolism ; Cytoplasm ; Disease Progression ; Humans ; Immunohistochemistry ; Nasopharyngeal Neoplasms ; metabolism ; Up-Regulation

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 kinases 4/6 (CDK4/6) inhibitors are anti-tumor agents for the treatment of hormone receptor-positive breast cancer. Palbociclib, abemaciclib and dalpiciclib have been approved for the treatment of breast cancer in China. Common adverse effects of CDK4/6 inhibitors include bone marrow suppression, gastrointestinal toxicities, liver dysfunction, and skin or subcutaneous tissue adverse reactions (AEs). The Breast Cancer Expert Group of Chinese Society of Clinical Oncology (CSCO) summarized the incidence, clinical manifestations, and grading of the AEs. This expert consensus reports measures of AE management on the basis of experience of clinical practice and the latest advances worldwide, aiming to guide clinical practice by the way of managing AE and help to choose the best treatment regimen.
Female ; Humans ; Aminopyridines/adverse effects* ; Antineoplastic Agents/adverse effects* ; Breast Neoplasms/drug therapy* ; Consensus ; Cyclin-Dependent Kinase 4/antagonists & inhibitors* ; Protein Kinase Inhibitors/adverse effects* ; Cyclin-Dependent Kinase 6/antagonists & inhibitors*

BACKGROUND: We aimed to determine the effect of fibronectin (FN)-immobilized microgrooved titanium (Ti) on human gingival fibroblast proliferation, gene expression and protein expression. METHODS: Photolithography was used to fabricate the microgrooved Ti, and amine funtionalization (silanization) was used for FN immobilization on titanium surfaces. Cell proliferation, gene expression and protein expression were analyzed, followed by multiple regression analysis for determining the influential factors on cell proliferation. RESULTS: FN-immobilized microgrooved Ti significantly enhanced the fibroblast proliferation in various timelines of culture, among which a burst of fivefold increase is induced at 96 h of culture compared to that on the control smooth Ti. We suggest a presence of the synergistic promotion effect of microgrooves and FN immobilization on fibroblast proliferation. Through a series of analyses on the expression of various genes and proteins involved in cell adhesion and proliferation, cyclin-dependent kinase 6, cyclin D1, integrin α5, oncogene c-Src, osteonectin, paxillin and talin-2 were determined as influential factors on promoting fibroblast proliferation induced by FN-immobilized microgrooved Ti. CONCLUSION: FN-immobilized microgrooved Ti can act as an effective surface for enhancing fibroblast proliferation, and can be used for promoting soft tissue response on the connective tissue attachment zone of biomaterial surfaces.
Cell Adhesion ; Cell Proliferation* ; Connective Tissue ; Cyclin D1 ; Cyclin-Dependent Kinase 6 ; Fibroblasts* ; Fibronectins ; Gene Expression ; Humans* ; Immobilization ; Oncogenes ; Osteonectin ; Paxillin ; Titanium*

OBJECTIVETo assess the effect of small interfering RNA (siRNA)-mediated suppression of CDK6 expression on the proliferation and cell cycles of nasopharyngeal carcinoma (NPC) cells in vitro.

METHODSQRT-PCR was used to examine the differential expression of CDK6 in 30 NPC tissues and 18 normal nasopharyngeal tissues. A siRNA targeting CDK6 was transfected in NPC CNE2 cells, and MTT assay and flow cytometry were used to analyze the changes in cell proliferation and cell cycle distribution. Western blotting was used to examine the expressions of the cell cycle-related factors.

RESULTSCompared with normal nasopharyngeal tissues, NPC tissues showed an increased expression of CDK6 mRNA. Knocking down CDK6 expression obviously inhibited tumor cell growth and cell cycle transition from G1 to S phase and caused reduced expressions of CDK4, CCND1, and E2F1 and enhanced expression of the tumor suppressor p21.

CONCLUSIONNPC tissues overexpress CDK6. Knocking down CDK6 expression inhibits the growth and cell cycle transition of NPC cells in vitro by inhibiting the expressions of CDK4, CCND1, and E2F1 and upregulating tumor suppressor p21 expression.

Carcinoma ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Cyclin-Dependent Kinase 6 ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; E2F1 Transcription Factor ; metabolism ; Gene Expression Regulation, Neoplastic ; Gene Knockdown Techniques ; Humans ; Nasopharyngeal Neoplasms ; pathology ; RNA, Messenger ; RNA, Small Interfering ; Transfection ; Up-Regulation