Pituitary tumors are usually benign but can occasionally exhibit hormonal and proliferative behaviors. Dysregulation of the G1/S restriction point largely contributes to the over-proliferation of pituitary tumor cells. F-box protein S-phase kinase-interacting protein-2 (SKP2) reportedly targets and inhibits the expression of p27(Kip1), a well-known negative regulator of G1 cell cycle progression. In this study, SKP2 expression was found to be upregulated while p27(Kip1) expression was determined to be downregulated in rat and human pituitary tumor cells. Furthermore, SKP2 knockdown induced upregulation of p27(Kip1) and cell growth inhibition in rat and human pituitary tumor cells, while SKP2overexpression elicited opposite effects on p27(Kip1) expression and cell growth. The expression of microRNA-186 (miR-186) was reported to be reduced in pituitary tumors. Online tools predicted SKP2 to be a direct downstream target of miR-186, which was further confirmed by luciferase reporter gene assays. Moreover, miR-186 could modulate the cell proliferation and p27(Kip1)-mediated cell cycle alternation of rat and human pituitary tumor cells through SKP2. As further confirmation of these findings, miR-186 and p27(Kip1) expression were downregulated, while SKP2 expression was upregulated in human pituitary tumor tissue samples; thus, SKP2 expression negatively correlated with miR-186 and p27(Kip1) expression. In contrast, miR-186 expression positively associated with p27(Kip1) expression. Taken together, we discovered a novel mechanism by which miR-186/SKP2 axis modulates pituitary tumor cell proliferation through p27(Kip1)-mediated cell cycle alternation.
Animals ; Cell Cycle ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27 ; Genes, Reporter ; Humans ; Luciferases ; Pituitary Neoplasms ; Rats ; Up-Regulation

BackgroundMicroRNA-24 (miR-24) plays an important role in heart failure by reducing the efficiency of myocardial excitation-contraction coupling. Prolonged cardiac hypertrophy may lead to heart failure, but little is known about the role of miR-24 in cardiac hypertrophy. This study aimed to preliminarily investigate the function of miR-24 and its mechanisms in cardiac hypertrophy.

MethodsTwelve Sprague-Dawley rats with a body weight of 50 ± 5 g were recruited and randomly divided into two groups: a transverse aortic constriction (TAC) group and a sham surgery group. Hypertrophy index was measured and calculated by echocardiography and hematoxylin and eosin staining. TargetScans algorithm-based prediction was used to search for the targets of miR-24, which was subsequently confirmed by a real-time polymerase chain reaction and luciferase assay. Immunofluorescence labeling was used to measure the cell surface area, and H-leucine incorporation was used to detect the synthesis of total protein in neonatal rat cardiac myocytes (NRCMs) with the overexpression of miR-24. In addition, flow cytometry was performed to observe the alteration in the cell cycle. Statistical analysis was carried out with GraphPad Prism v5.0 and SPSS 19.0. A two-sided P < 0.05 was considered as the threshold for significance.

ResultsThe expression of miR-24 was abnormally increased in TAC rat cardiac tissue (t = -2.938, P < 0.05). TargetScans algorithm-based prediction demonstrated that CDKN1B (p27, Kip1), a cell cycle regulator, was a putative target of miR-24, and was confirmed by luciferase assay. The expression of p27 was decreased in TAC rat cardiac tissue (t = 2.896, P < 0.05). The overexpression of miR-24 in NRCMs led to the decreased expression of p27 (t = 4.400, P < 0.01), and decreased G0/G1 arrest in cell cycle and cardiomyocyte hypertrophy.

ConclusionMiR-24 promotes cardiac hypertrophy partly by affecting the cell cycle through down-regulation of p27 expression.

Animals ; Cardiomegaly ; genetics ; pathology ; Cell Cycle ; genetics ; physiology ; Cyclin-Dependent Kinase Inhibitor p27 ; genetics ; metabolism ; Male ; MicroRNAs ; genetics ; Myocardium ; metabolism ; Myocytes, Cardiac ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley

The Jun activation-domain binding protein 1 (Jab1) recognize a potential coactivator of activator protein 1 (AP-1) such as c-fos, c-jun transcription factor and the fifth subunit of the COP9 signalosome complex. Also, Jab1 activate the c-jun gene resulted cell proliferation. Not only a powerful tumor suppressor but also regulator of apoptosis negative cdk inhibitor p27(kip1) are involved in the cell cycle. This is Jab1 and p27(kip1) interact with each other, Jab1 accelerate p27(kip1) from nuclear to cytoplasm through ubiquitin/proteasome pathway. However, information about the relationship between Jab1 and p27(kip1) is not known much. Taken together, the results of this study identify function and structure of Jab1 and p27(kip1) were described in a recent article on the basis of relevant. Besides Jab1 and p27(kip1) will organize the relationship between the disease and women.
Apoptosis ; Breast Neoplasms ; Carrier Proteins* ; Cell Cycle ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27 ; Cytoplasm ; Endometriosis ; Female ; Genes, jun ; Humans ; Ovarian Neoplasms ; Transcription Factor AP-1 ; Transcription Factors

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

BACKGROUND: Papillary thyroid carcinoma (PTC) is frequently accompanied by lymphocytic thyroiditis (LT). Some reports claim that Hashimoto's thyroiditis (the clinical form of LT) enhances the likelihood of PTC; however, others suggest that LT has antitumor activity. This study was aimed to find out the relationship between the patterns of helper T cell (Th) cytokines in thyroid tissue of PTC with or without LT and the clinicopathological manifestation of PTC. METHODS: Fresh surgical samples of PTC with (13 cases) or without (10 cases) LT were used. The prognostic parameters (tumor size, extra-thyroidal extension of PTC, and lymph node metastasis) were analyzed. The mRNA levels of two subtypes of Th cytokines, Th1 (tumor necrosis factor α [TNF-α], interferon γ [IFN-γ ], and interleukin [IL] 2) and Th2 (IL-4 and IL-10), were analyzed. Because most PTC cases were microcarcinomas and recent cases without clinical follow-up, negative or faint p27 immunoreactivity was used as a surrogate marker for lymph node metastasis. RESULTS: PTC with LT cases showed significantly higher expression of TNF-α (p = .043), IFN-γ (p < .010), IL-4 (p = .015) than those without LT cases. Although the data were not statistically significant, all analyzed cytokines (except for IL-4) were highly expressed in the cases with higher expression of p27 surrogate marker. CONCLUSIONS: These results indicate that mixed Th1 (TNF-α, IFN-γ , and IL-2) and Th2 (IL-10) immunity might play a role in the antitumor effect in terms of lymph node metastasis.
Biomarkers ; Cyclin-Dependent Kinase Inhibitor p27 ; Cytokines ; Follow-Up Studies ; Interferons ; Interleukin-4 ; Interleukins ; Lymph Nodes ; Necrosis ; Neoplasm Metastasis ; RNA, Messenger ; T-Lymphocytes, Helper-Inducer ; Thyroid Gland ; Thyroid Neoplasms ; Thyroiditis ; Thyroiditis, Autoimmune*

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

OBJECTIVETo investgate the effects of rapamycin(RPM)and RPM-loaded poly(lactic-co-glycolic)acid(PLGA)nanoparticles(NPs)on the apoptosis of human umbilical arterial vascular smooth muscle cells(HUASMCs)in vitro and expression of bcl-2 and p27(kip1) protein.

METHODSHUASMCs were cultured in vitro and divided to RPM and RPM-PLGA-NPs groups treated at 3 different concentration by 12 and 24 hours,with M231-smooth muscle growth supplements medium and null-PLGA-NPs treated groups as controlled. The apoptosis of HUASMCs was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining and flow cytometry. The expressions of bcl-2 and p27(kip1) were detected by streptacidin/peroxidase immunohistochemical method. The effect on cellular proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidecolorimetry.

RESULTSThe proliferation of HUASMCs was inhibited by RPM and RPM-PLGA-NPs in a dose-dependent manner. DNA electrophoresis showed DNA ladder in RPM and RPM-PLGA-NPs groups and classical scalar strips in control groups. The apoptotic indexes of RPM 100 ng/ml group and RPM-PLGA-NPs 500 ng/ml group detected by flow cytometry were(45.45<2.36)% and(35.04<5.64)%,respectively,which were significantly higher than that of M231-smooth muscle growth supplements control group [(2.60<0.95)%,all P<0.01]. The apoptotic indexes of groups incubated with RPM and RPM-PLGA-NPs for 24 hours were significantly higher than those of groups which incubated for 12 hours(P<0.05,P<0.01). The positive expression indexes(PEI)of p27(kip1) and bcl-2 protein were higher in RPM and RPM-PLGA-NPs groups than that of control groups. The Spearman's rank correlation coefficient test showed that there was no significant correlation between the PEI of p27(kip1) and the apoptotic indexes in the RPM group and RPM-PLGA-NPs group(P>0.05).

CONCLUSIONSRapamycin-loaded PLGA nanoparticles and rapamycin have similar effects in inhibiting proliferation and inducing apoptosis;meanwhile,they upregulate the expression of p27(kip1) protein without downregulating the expression of bcl-2 protein in HUASMCs in vitro. RPM-PLGA-NPs has more potent pro-apoptotic effect than equivalent dose of RPM but is not linearly correlated with the p27(kip1) expression level.

Apoptosis ; Cell Proliferation ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p27 ; Humans ; In Situ Nick-End Labeling ; Lactic Acid ; Muscle, Smooth, Vascular ; Myocytes, Smooth Muscle ; Nanoparticles ; Polyglycolic Acid ; Sirolimus ; Umbilical Arteries

OBJECTIVETo observe the effect of p27 gene recombinant adenovirus combined with Chinese medicine Pientzehuang ([characters: see text]) on the growth of xenografted human osteosarcoma in nude mice.

METHODSTissue transplantation was used to construct the orthotopic model of human osteosarcoma Saos-2 cell in nude mice. Thirty tumor-bearing nude mice were randomly divided into 5 groups with 6 mice in each group: blank control group (model of osteosarcoma), empty vector group (recombinant adeno-associated virus-multiple cloning site), Pientzehuang group, p27 gene group and combined treatment group (p27 gene combined with Pientzehuang). The effect of combined treatment on human osteosarcoma was analyzed through the tumor formation, tumor volume and inhibition rate of tumor growth. The expression of p27 was measured by immunohistochemical staining and Western blot.

RESULTSThe orthotopic model of osteosarcoma in nude mice was successfully constructed. The general appearance of tumor-bearing nude mice in Pientzehuang and p27 gene groups was markedly improved compared with the blank control group; and in the combined treatment group it was significantly improved compared with the Pientzehuang and p27 gene groups. The tumor growth in the Pientzehuang and p27 gene groups was significantly inhibited compared with the blank control group P<0.05); while in the combined treatment group it was markedly inhibited compared with the Pientzehuang and p27 gene groups (P<0.05). The rates of tumor growth inhibition were 34.1%, 56.5% and 63.8% in the Pientzehuang, p27 gene and combined treatment groups, respectively. Meanwhile, the protein expression of p27 gene in the p27 gene group was significantly increased compared with the blank control group (P<0.05); and it was significantly increased in the combined treatment group compared with the p27 gene and Pientzehuang groups (P<0.05).

CONCLUSIONp27 gene introduced by adenovirus combined with Pientzehuang can inhibit the growth of human osteosarcoma cell Saos-2 in nude mice.

Adenoviridae ; Animals ; Blotting, Western ; Bone Neoplasms ; pathology ; Cell Line ; Cyclin-Dependent Kinase Inhibitor p27 ; genetics ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Immunohistochemistry ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Osteosarcoma ; pathology ; Sarcoma, Experimental ; pathology ; Transplantation, Heterologous

Although previous reports showed drug-eluting stent (DES) could effectively inhibit neointima formation, in-stent restenosis (ISR) remains an important obstacle. The purpose of this study was to investigate different effects of paclitaxel on proliferation and cell cycle regulators between vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs) of rats in vitro. The cultured VSMCs and VECs of rats from the same tissues were examined by using immunohistochemistry, flow cytometry and Western blotting in control and paclitaxel-treated groups. The results showed paclitaxel could effectively inhibit proliferation of VSMCs and VECs. However, as compared with VECs, proliferation of VSMCs in paclitaxel-treated group decreased less rapidly. The percentage of cells in G0-G1 and G2-M phases was reduced, and that in S phase increased after treatment for 72 h. The expression of cyclin D1 and B1, p27 and PCNA in VSMCs of paclitaxel-treated group was up-regulated, but that of p21 down-regulated as compared with VECs. It is concluded that there are significant differences in the expression of cell cycle regulators and proliferation rate between paclitaxel-treated VSMCs and paclitaxel-treated VECs, suggesting that the G1-S checkpoint regulated by paclitaxel may play a critical role in the development of complications of DES, which provides new strategies for treatments of ISR.
Animals ; Blotting, Western ; Cell Cycle ; drug effects ; Cell Cycle Proteins ; metabolism ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin B1 ; metabolism ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Endothelial Cells ; drug effects ; metabolism ; Flow Cytometry ; G1 Phase Cell Cycle Checkpoints ; drug effects ; Immunohistochemistry ; Microscopy, Fluorescence ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; Paclitaxel ; pharmacology ; Proliferating Cell Nuclear Antigen ; metabolism ; Rats ; Tubulin Modulators ; pharmacology

Although it has been suggested that kinesin family member 14 (KIF14) has oncogenic potential in various cancers, including hepatocellular carcinoma (HCC), the molecular mechanism of this potential remains unknown. We aimed to elucidate the role of KIF14 in hepatocarcinogenesis by knocking down KIF14 in HCC cells that overexpressed KIF14. After KIF14 knockdown, changes in tumor cell growth, cell cycle and cytokinesis were examined. We also examined cell cycle regulatory molecules and upstream Skp1/Cul1/F-box (SCF) complex molecules. Knockdown of KIF14 resulted in suppression of cell proliferation and failure of cytokinesis, whereas KIF14 overexpression increased cell proliferation. In KIF14-silenced cells, the levels of cyclins E1, D1 and B1 were profoundly decreased compared with control cells. Of the cyclin-dependent kinase inhibitors, the p27Kip1 protein level specifically increased after KIF14 knockdown. The increase in p27Kip1 was not due to elevation of its mRNA level, but was due to inhibition of the proteasome-dependent degradation pathway. To explore the pathway upstream of this event, we measured the levels of SCF complex molecules, including Skp1, Skp2, Cul1, Roc1 and Cks1. The levels of Skp2 and its cofactor Cks1 decreased in the KIF14 knockdown cells where p27Kip1 accumulated. Overexpression of Skp2 in the KIF14 knockdown cells attenuated the failure of cytokinesis. On the basis of these results, we postulate that KIF14 knockdown downregulates the expression of Skp2 and Cks1, which target p27Kip1 for degradation by the 26S proteasome, leading to accumulation of p27Kip1. The downregulation of Skp2 and Cks1 also resulted in cytokinesis failure, which may inhibit tumor growth. To the best of our knowledge, this is the first report that has identified the molecular target and oncogenic effect of KIF14 in HCC.
Carcinoma, Hepatocellular/*metabolism ; Cyclin-Dependent Kinase Inhibitor p27/genetics/*metabolism ; Cyclins/genetics/metabolism ; *Cytokinesis ; Gene Silencing ; Hep G2 Cells ; Humans ; Kinesin/genetics/*metabolism ; Liver Neoplasms/*metabolism ; Oncogene Proteins/genetics/*metabolism ; Proteasome Endopeptidase Complex/metabolism ; RNA, Messenger/genetics/metabolism ; S-Phase Kinase-Associated Proteins/genetics/metabolism ; *Ubiquitination