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

OBJECTIVETo study the expression of phosphatase and tensin homology deleted on chromosometen ten (PTEN) protein, a tumor suppressor gene in breast cancer and its correlation with p27(kip1) and cyclin D1 expression.

METHODSPTEN protein expression, p27(kip1) and cyclin D1 protein expression were detected by immunohistochemical method in paraffin sections from 61 women with primary breast cancer. PTEN protein expression was compared with clinico-pathologic parameters as related to p27(kip1) and cyclin D1.

RESULTSPTEN, being shown in the cytoplasm, was negative in 6.6% (4/61), reduced in 41.0% (25/61) and positive in 52.5% (32/61) samples. PTEN expression level was correlated with axillary lymph node status, loss of estrogen receptor stain, recurrence and metastasis. On univariate analysis, the disease-free survival rate of patients with higher PTEN expression (> 50% cells stained) was better than those with lower expression (P = 0.0101). However, there was no correlation between p27(kip1), cyclin D1 expression or PTEN expression.

CONCLUSIONPTEN, its lower expression being correlated with poor outcome of breast cancer patients, plays a prominent role in breast cancer. p27(kip1) or cyclin D1 may not be the primary downstream genes of PTEN in breast cancer.

Adult ; Aged ; Breast Neoplasms ; chemistry ; mortality ; pathology ; Cyclin D1 ; analysis ; physiology ; Cyclin-Dependent Kinase Inhibitor p27 ; Female ; Humans ; Immunohistochemistry ; Intracellular Signaling Peptides and Proteins ; analysis ; physiology ; Lymphatic Metastasis ; Middle Aged ; PTEN Phosphohydrolase ; analysis ; physiology ; Prognosis

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

OBJECTIVETo study the role of cyclinD1 and CDK4 in malignant transformation of human fetal lung diploid fibroblast cell line (2BS) induced by silica.

METHODSRecombination vectors with sense and antisense pXJ41-cyclinD1 and pXJ41-CDK4 were constructed, and then transfected into the malignant transformed cells induced by silica, respectively. At the same time, pXJ41-neo was used as the control.

RESULTSDuring the progress of the malignant transformation of 2BS cells induced by silica, cyclinD1 and CDK4 were overexpressed. Antisense RNA suppressed cyclinD1 and CDK4 gene expression in the antisense pXJ41-cyclinD1 and pXJ41-CDK4 transfected cells. Antisense RNA led to cell cycle arrest, resulting in lengthened G1 phase (the percentages of cells in the G1 phase changed from 45.1% to 52.7% and 58.0% for cyclinD1 and CDK4 transfected cells, respectively), and eventually attenuated the increase of the proliferation of malignant transformed cells induced by silica. Compared with malignant transformed cells induced by silica, cells transfected with antisense pXJ41-cyclinD1 and pXJ41-CDK4 showed obviously reduced growth rates. On the 8th day, the suppression rates were 58.69 and 77.43% (the growth rate of malignant transformed cells induced by silica was 100%), doubling time changed from 21.0 h to 31.4 h and 21.0 h to 42.7 h, respectively, the growth capacities on soft agar of cells transfected by antisense pXJ41-cyclinD1 and pXJ41-CDK4 decreased obviously.

CONCLUSIONCyclinD1 and CDK4 play an important role in maintaining transformed phenotype of the cancer cells.

Carcinogens, Environmental ; toxicity ; Cell Line ; Cell Proliferation ; Cell Transformation, Neoplastic ; chemically induced ; Cyclin D1 ; genetics ; metabolism ; physiology ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; physiology ; Humans ; Plasmids ; RNA, Antisense ; metabolism ; RNA, Messenger ; analysis ; metabolism ; Silicon Dioxide ; toxicity

OBJECTIVETo investigate the role that E-cadherin (E-cad) plays on cell adhesion and proliferation of human breast carcinoma.

METHODSE-cad expression vector was transfected into an E-cad-negative human breast carcinoma MDA-MB-231 cells. G418 was used to screen positive clones. E-cad, β-catenin (β-cat) and cyclin D1 expressions of these clones were confirmed by Western blot. Their cell-cell and cell-matrix adhesion abilities were detected. E-cad/β-catenin interaction was confirmed by immunoprecipitation. Cell proliferation was evaluated by MTT. Cell apoptosis was analyzed by flow cytometry. Direct two-step immunocytochemistry was used to detect the localization of β-cat.

RESULTE-cad(+) cell strains Ecad-231-7 and Ecad-231-9 were established. When cultured in ultra-low-binding dishes Ecad-231 cells grow in suspension while Ecad-231-7 and Ecad-231-9 cells grow in large clamps. When co-cultured with HCT116 cells, the average adhesion rates at 30 min are 39.0%, 60.0% and 59.5% for MDA-MB-231, Ecad-231-7 and Ecad-231-9 respectively. The average detachment rates by EDTA for 5 min are 37.4%, 4.2% and 7.4% respectively. So E-cad expression enhanced hemotypic and heterotypic cell-cell adhesion and cell-matrix adhesion. Forced exogenously expressed E-cad could combine with endogenous β-cat, whereas down stream cyclin D1 expression was significantly decreased, as evidenced by Western blot. The rates of cell apoptosis of MDA-MB-231, Ecad-231-7 and Ecad-231-9 were 1.8%, 2.0% and 2.1%. Expression of E-cad had no obvious effect on the apoptosis of tumor cells with regular culture. β-cat increased in the cytoplasma.

CONCLUSIONSTwo monoclonal tumor cell strains (Ecad-231-7 and Ecad-231-9) stably expressing E-cad were successfully established. E-cad could enhance adhesion and inhibit proliferation of human breast carcinoma cells through a pathway involving β-cat and cyclin D1.

Apoptosis ; Breast Neoplasms ; metabolism ; pathology ; Cadherins ; genetics ; metabolism ; physiology ; Cell Adhesion ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1 ; metabolism ; Female ; Genetic Vectors ; Humans ; Plasmids ; Transfection ; beta Catenin ; metabolism

OBJECTIVETo investigate the role of HPV16E6 and E7 during the transformation of oral epithelial cells.

METHODSAn human immortalized oral epithelial cell line (HIOEC) was established by transfecting HPV16E6, E7 open reading frames using recombinant retroviral system plxsn to human normal oral epithelial cells. Expression of HPV16E6, E7, Rb, P16 and Cycin D1 were analyzed by Western blot in HIOEC and human normal oral epithelial cells. Formation of complex of HPV16E7 and Rb were analyzed by Immunoprecipitation-western blot. Human normal oral epithelial cells and the oral epithelial cells transfected with plxsn were used as control groups.

RESULTSHIOEC expressed HPV16 E6 and E7; HIOEC expressed both hyperphosphorylated and underphosphorylated Rb while oral epithelial cells in two control groups only expressed hyperphosphorylated Rb. HPV16 E7 formed complex with underphosphorylated Rb; the level of P16 and Cyclin D1 had no remarkable change.

CONCLUSIONSHPV16E7 plays an important role in the immortalization of oral epithelial cells induced by HPV16.

Blotting, Western ; Cell Line ; Cell Transformation, Neoplastic ; Cyclin D1 ; analysis ; Cyclin-Dependent Kinase Inhibitor p16 ; analysis ; Humans ; Mouth Mucosa ; metabolism ; pathology ; virology ; Oncogene Proteins, Viral ; physiology ; Papillomavirus E7 Proteins ; Phosphorylation ; Repressor Proteins ; Retinoblastoma Protein ; analysis

OBJECTIVELipoxin A(4) is formed by the metabolism of arachidonic acid. Anti-inflammatory and anti-proliferative effect of lipoxin A(4) has been shown in many human diseases. Recently, as a novel high affinity receptor for ligand lipoxin A(4), Lipoxin A(4) receptor-like protein (LRLP) has been identified. Currently close attention is paid to the important contribution of connective tissue growth factor (CTGF) in lung fibrosis. The purpose of the study was to transfect LRLP gene into human lung fibroblasts and investigate the mechanism of its enhancing antagonistic effect of Lipoxin A(4) on human lung fibroblasts proliferation induced by connective tissue growth factor.

METHODSEukaryocytic expression vector pEGFP/LRLP which contained LRLP and green fluorescence protein fusion gene (GFP) was constructed and transfected into human lung fibroblasts (HLF). After selecting with G418, HLF/LRLP cell clone which stably expressed LRLP/GFP fusion protein was isolated and characterized by the laser scanning confocal microscope. Cultured HLF and HLF/LRLP were stimulated for 24 h with CTGF (1 microg/ml) in the presence and absence of pretreatment of Lipoxin A(4) (10.0 nmol/L) for 30 min. Inhibition of cell proliferation was determined by MTT assay. Cell cycle analysis was performed by flow cytometry. Western blot was used to detect the expression of cyclin D(1) protein. Electrophoretic mobility shift assay (EMSA) was employed to detect the DNA binding activity of STAT(3).

RESULTS(1) HLF/LRLP cell clone which stably expressed LRLP and GFP fusion protein was successfully obtained. (2) Proliferation of HLF and HLF/LRLP was induced by 1 microg/ml CTGF. Pretreatment with 10 nm Lipoxin A(4) inhibited the proliferation of HLF and HLF/LRLP. And the inhibitory rate of HLF/LRLP was significantly higher than that of HLF [(54.1 +/- 4.2)%, (21.2 +/- 3.7)%, P < 0.05]. (3) The flow cytometry analysis showed that compared with HLF, more HLF/LRLP were arrested at G(0)/G(1) phase in the presence of pretreatment of Lipoxin A(4). [(76.3 +/- 3.5)%, (60.8 +/- 2.0)%, P < 0.05]. (4) Ten nmol/L Lipoxin A(4) antagonized CTGF induced increase of cyclin D(1) protein expression in HLF and HLF/LRLP. And its antagonistic effect on HLR/LRLP was stronger than that on HLF (P < 0.05). (5) Ten nmol/L Lipoxin A(4) antagonized CTGF induced increase of STAT(3) DNA binding activity, and its antagonistic effect on HLF/LRLP was more powerful than that on HLF (P < 0.05).

CONCLUSIONSTransfection of Lipoxin A(4) receptor-like protein gene enhanced the inhibitory effect of Lipoxin A(4) on human lung fibroblasts proliferation induced by CTGF. Its mechanism might be related to regulation of cyclin D(1) protein expression and STAT(3) DNA binding activity.

Connective Tissue Growth Factor ; antagonists & inhibitors ; Cyclin D1 ; analysis ; DNA ; metabolism ; Fibroblasts ; cytology ; drug effects ; Humans ; Lipoxins ; pharmacology ; Lung ; cytology ; drug effects ; Receptors, Formyl Peptide ; genetics ; physiology ; Receptors, Lipoxin ; genetics ; physiology ; STAT3 Transcription Factor ; metabolism ; Transfection

BACKGROUNDDecorin is a small leucine-rich proteoglycan and it plays an important role in regulation of cell growth and migration in various tumor cell lines. Decorin was found down-regulated in non-small cell lung cancer tissue and may be involved in regulation of lung cancer development.

METHODSIn this study, lentivirus-mediated RNA interference and over expression were employed to change the expression levels of decorin in lung cancer A549 cells. We tested the cell cycle of A549 cells and the expression of transforming growth factor (TGF)-β, cyclin D1, epidermal growth factor receptor (EGFR), P53, and P21.

RESULTSWe found that up-regulation of decorin could inhibit proliferation, block cell cycle at G1 and decrease invasive activity of A549 cells. Moreover, we also show that up-regulation of decorin induced significant decreases of TGF-β1, cyclin D1 expression, phosphorylation of EGFR, and increases of P53 and P21 expression. Opposite results were observed in A549 cells with down-regulation of decorin.

CONCLUSIONOur results suggest that decorin is a key regulator involved in proliferation and migration of A549 cells.

Cell Cycle ; genetics ; physiology ; Cell Movement ; genetics ; physiology ; Cell Proliferation ; Cyclin D1 ; genetics ; metabolism ; Decorin ; genetics ; metabolism ; Humans ; Receptor, Epidermal Growth Factor ; genetics ; metabolism ; Transforming Growth Factor beta ; genetics ; metabolism ; Tumor Cells, Cultured

BACKGROUNDAirway smooth muscle (ASM) is suspected to be a determining factor in the structural change of asthma. However, the role of protein kinase C alpha (PKCalpha) and cyclin D1 involved in the dysfunction of ASM leading to asthmatic symptoms is not clear. In this study, the central role of PKCalpha and cyclin D1 in ASM proliferation in asthmatic rats was explored.

METHODSThirty-six pathogen-free male Brown Norway (BN) rats were randomly divided into 2 groups: control groups (group N1, N2 and N3) and asthmatic groups (group A1, A2, and A3). Groups A1, A2 and A3 were challenged with ovalbumin (OA) for 2 weeks, 4 weeks and 8 weeks respectively. Control animals were exposed to an aerosolized sterile phosphate buffered saline (PBS). The ASM mass and nucleus numbers were studied to estimate the degree of airway remodeling by the hematoxylin-eosin staining method. PKCalpha and cyclin D1 expression in the ASM cells was detected by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The relation between PKCalpha and cyclin D1 was assessed by linear regression analysis. PKC agonist phorbol 12-myristate 13-acetate (PMA), PKC inhibitor Ro31-8220 and an antisense oligonucleotide against cyclin D1 (ASOND) were used to treat ASM cells (ASMCs) obtained from the 2 weeks asthmatic rats. The cyclin D1 protein expression level was detected by Western blotting.

RESULTSCompared with the control group, the PKCalpha and cyclin D1 mRNA levels were increased in the asthmatic group. Similar to RT-PCR results, immunohistochemistry analysis for PKCalpha and cyclin D1 expression revealed an increased production in ASMCs after allergen treatment for 2, 4 and 8 weeks compared with the respective control groups. No difference in expression of PKCalpha and cyclin D1 in ASM were found in the 2, 4 or 8 weeks asthmatic rats. There were significant positive correlations between PKCalpha and cyclin D1 expression, both transcriptionally (r = 0.944, P < 0.01) and translationally (r = 0.826, P < 0.01), in ASM. The content of cyclin D1 in asthmatic ASMCs increased after being stimulated by PMA, and decreased when induced by Ro31-8220. ASOND targeting for cyclin D1 lowered the expression of cyclin D1 induced by PMA.

CONCLUSIONSIncreased expression of PKCalpha and cyclin D1 in ASM along with smooth muscle structure changes might implicate PKCalpha and cyclin D1 participation in the proliferation of ASM and contribute to the pathogenesis of asthma after repeated allergen exposure in rats. The results suggested that cyclin D1 might be downstream of PKC signal transduction pathway.

Animals ; Asthma ; pathology ; Cell Proliferation ; Cyclin D1 ; genetics ; physiology ; Lung ; pathology ; Male ; Myocytes, Smooth Muscle ; pathology ; Protein Kinase C-alpha ; genetics ; physiology ; RNA, Messenger ; analysis ; Rats ; Rats, Inbred BN

BACKGROUNDExposure to cigarette smoke stimulates the proliferation of human pulmonary artery smooth muscle cells (HPASMCs) in vivo and in vitro. However, the molecular mechanism remains unclear. This study aimed at investigating the role of signaling pathways involving protein kinase C alpha (PKCα) and cyclin D1 in the cigarette smoke extract (CSE)-induced HPASMCs proliferation.

METHODSSynchronized HPASMCs were treated with different concentrations of CSE. Cell proliferation was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell counting. Cell cycle was analyzed by flow cytometry with propidium iodide staining. Activation of PKCα was measured by detecting the expression of PKCα protein in the cytosolic and membrane fractions using Western blotting analysis. Small interfering RNA (siRNA) was used to knockdown PKCα and cyclin D1. The cyclin D1 mRNA was assessed by real-time RT-PCR. The PKCα and cyclin D1 protein levels were detected by Western blotting.

RESULTSLow concentrations of CSE (1% - 10%) stimulated proliferation of HPASMCs, with its maximal effect at 5%. CSE (5%) led to PKCα activation. Inhibition of PKCα activity using Gö 6976 or siRNA-mediated knockdown of PKCα significantly attenuated CSE-induced cell proliferation and G1/S transition. Cyclin D1, one of key regulators of G1/S transition, was found to be upregulated by 5% CSE at both the mRNA and protein levels. CSE-stimulated cell proliferation and G1/S transition was abolished by cyclin D1 siRNA. Moreover, Gö 6976 or PKCα siRNA significantly suppressed CSE-induced upregulation of cyclin D1 at both the mRNA and protein levels.

CONCLUSIONPKCα-cyclin D1 pathway at least partially mediates the CSE-induced proliferation in HPASMCs.

Cell Proliferation ; Cells, Cultured ; Cyclin D1 ; physiology ; G1 Phase ; Humans ; Muscle, Smooth, Vascular ; pathology ; Myocytes, Smooth Muscle ; pathology ; Protein Kinase C-alpha ; physiology ; Pulmonary Artery ; pathology ; S Phase ; Signal Transduction ; Smoke ; adverse effects ; Tobacco ; adverse effects