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 investigate the biological function of RIG-G gene by establishing a cell line stably expressing RIG-G protein.

METHODSEctopic RIG-G gene was transfected into U937 cells by using Tet-off expression system. Changes before and after RIG-G expression were detected for cell growth, cell morphology, cell surface antigen and cell cycle regulating proteins.

RESULTSRIG-G protein arrested the cells at G0/G1 phase and inhibited cell growth by increasing the cell cycle inhibitors P21 and P27. As compared to that in control group, the proportion of cells at G0/G1 phase in RIG-G-expressing cell group increased from (43.9 +/- 5.6)% to (63.9 +/- 2.3)% (P < 0.01). The rate of growth inhibition was (68.7 +/- 0.2)%. In addition, an increase in CD11C expression [(61.3 +/- 1.1)% vs. (18.0 +/- 0.4)% (P < 0.01)] and in cells with morphologic features of partial differentiation (smaller cell size, reduced nucleus-cytoplasm ratio, notched nucleus and coarse chromatin) was also observed in RIG-G-expressing cells.

CONCLUSIONSRIG-G has potential abilities to inhibit cell proliferation and promote cell differentiation.

Cell Cycle ; genetics ; Cell Differentiation ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; genetics ; metabolism ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; physiology ; Plasmids ; genetics ; Transfection ; U937 Cells

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

OBJECTIVETo detect the expression of cell cycle positive regulators cyclin D(1), cyclin E, CDK(2), CDK(4) and negative regulators p21(cip1), p27(kip1), p16(ink4a) and p15(ink4b) during wound healing in rats.

METHODSOpen wounds of full-thickness skin, diameter 1.8 cm, on rat backs were used as the wound model. Wound tissues were harvested on postwounding days 3, 5, 7, 9, 11, 14, 21 and 30. Ki67 expression in granulation tissue was detected by immunohistochemical assay. The patterns of the expression of cyclin D(1), cyclin E, CDK(2), CDK(4) and p21(cip1), p27(kip1), p16(ink4a), p15(ink4b) were detected by Western blot.

RESULTSCell proliferation in granulation tissue took place predominantly within the first week after injury, with the proliferation peak occurring at postwounding day 5. There were no dramatic variations in the expression of cyclin D(1), CDK(2) and CDK(4) during wound healing. Up-regulated cyclin E was maintained from day 3 to 11 after injury, and then was down-regulated. No expression of p16(ink4a) and p15(ink4b) was found. p21(cip1) was expressed only from day 7 to 14, with peak expression observed on day 9. Constitutive p27(kip1) was expressed throughout wound healing with low levels in the proliferating period of day 3 to 5 and with increased levels in the post-mitotic and remodeling stage. The expression of p21(cip1) and p27(kip1) showed an inverse gradient to that of Ki67.

CONCLUSIONp21(cip1) and p27(kip1) play a supervising role in preventing the hyperproliferative tendency in tissue repair.

Animals ; Cell Cycle ; physiology ; Cell Cycle Proteins ; biosynthesis ; physiology ; Cell Division ; physiology ; Cyclin-Dependent Kinase Inhibitor p16 ; biosynthesis ; Cyclin-Dependent Kinase Inhibitor p27 ; Cyclin-Dependent Kinases ; antagonists & inhibitors ; biosynthesis ; Cyclins ; biosynthesis ; Male ; Rats ; Rats, Wistar ; Skin ; cytology ; metabolism ; Tumor Suppressor Proteins ; biosynthesis ; physiology ; Wound Healing

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 investigate whether the connection of p27(Kip1) to S-phase kinase-associated protein 2 (Skp2) plays an oncogenic role in intraductal proliferative lesions of the breast.

METHODSHere we investigated the mechanism involved in association of Skp2’s degradation of p27(Kip1) with the breast carcinogenesis by immunohistochemical method through detection of Skp2 and p27(Kip1) protein levels in 120 paraffin-embedded tissues of intraductal proliferative lesions including usual ductal hyperplasia (UDH, n=30), atypical ductal hyperplasia (n=30), flat epithelial atypia (FEA, n=30), and ductal carcinoma in situ (DCIS, n=30). Moreover, the expression status of Skp2 and p27(Kip1) in 30 cases of the normal breast paraffin-embedded tissues were explored.

RESULTSThe DCIS group was with the highest Skp2 level and the lowest p27(Kip1) level, and the UDH group was with the lowest Skp2 level and the highest p27(Kip1) level.Both Skp2 and p27(Kip1) levels in the DCIS group were significantly different from those in the UDH group (all P<0.01).The levels of Skp2 and p27(Kip1) in the FEA group were significantly different from both the DCIS and UDH groups (all P<0.05).p27(Kip1) was negatively correlated with Skp2 in both the UDH group (r=-0.629, P=0.026) and DCIS group (r=-0.893, P=0.000).

CONCLUSIONOverexpression of Skp2 might be the mechanism underlying p27(Kip1) over degradation.

Adult ; Aged ; Breast ; pathology ; Breast Neoplasms ; etiology ; Carcinoma, Intraductal, Noninfiltrating ; etiology ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27 ; physiology ; Female ; Humans ; Hyperplasia ; Middle Aged ; S-Phase Kinase-Associated Proteins ; physiology

OBJECTIVECytotoxin-associated protein (CagA) of H. pylori has been confirmed to be closely associated with gastric inflammation and tumorigenesis, but the mechanism behind it is little understood. In this study, we try to determine roles of CagA(+) strain in activating PI3K/Akt1 signaling pathway, and affecting expression of p21(WAF1/CIP1) and p27(KIP1), and also in releasing IL-8 in host cells.

METHODSAkt1 phosphorylation and IL-8 levels of CagA(+) and CagA⁻ strain infected AGS cells were detected by ELISAs. Two quantitative RT-PCRs were established to measure p21(WAF1/CIP1) and p27(KIP1) mRNA levels in the CagA(+) and CagA⁻ strain infected cells. LY294002, an inhibitor of PI3K/Akt pathway, was used to define effect of the pathway in IL-8 release.

RESULTSCagA(+) strain could induce an obvious elevation of Akt1 phosphorylation in the infected AGS cells while CagA? strain failed to do so. The CagA(+) H. pylori strain infected AGS cells showed significant drops both in p21(WAF1/CIP1) and p27(KIP1) mRNA levels, whereas the CagA⁻ H. pylori strain caused a remarkable increase in p21(WAF1/CIP1) mRNA without affecting p27(KIP1) gene transcription in the AGS cells. Both the CagA(+) and CagA⁻ H. pylori strains enabled AGS cells to produce close elevated levels of IL-8, and the LY294002 block resulted in unexpected elevations of IL-8 levels.

CONCLUSIONSCagA can activate PI3K/Akt1 pathway that plays an inhibitory role in IL-8 release in H. pylori infected AGS cells. Activation of PI3K/Akt1 pathway and subsequent negative regulation of p21(WAF1/CIP1) and p27(KIP1) expression might be involved in CagA-associated carcinogenesis.

Antigens, Bacterial ; genetics ; physiology ; Bacterial Proteins ; genetics ; physiology ; Cell Line ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; Cyclin-Dependent Kinase Inhibitor p27 ; Gastric Mucosa ; cytology ; enzymology ; microbiology ; Helicobacter pylori ; metabolism ; pathogenicity ; physiology ; Humans ; Interleukin-8 ; secretion ; Intracellular Signaling Peptides and Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Transcription, Genetic ; Virulence

BACKGROUNDRenal hypertrophy has been regarded as the early feature of diabetic nephropathy (DN), which may eventually lead to proteinuria and renal fibrosis. However, the exact mechanism of renal hypertrophy is still unclear. The aim of this study was to investigate the possible association of connective tissue growth factor (CTGF) with renal hypertrophy in uninephrectomized diabetic rats.

METHODSSeventy-two Sprague-Dawley (SD) rats were randomly divided into two groups: control group (group C, n = 32) and diabetic nephropathy (group DN, n = 40). Each group was re-divided into 4 subgroups according to the experimental period. The rats were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ) after rats had received uninephrectomy. Blood glucose (BG), body weight (BW), 24-h urinary albumin excretion (24hUalb), kidney weight (KW), KW/BW, glomerular tuft area (AG), glomerular tuft volume (VG), proximal tubular area (AT) at each time point, the width of glomerular basement membrane (GBM) and tubular basement membrane (TBM) at week 8 were measured when the rats were sacrificed. Renal expression of CTGF and p27kip1 were detected by immunohistochemical staining. The relationship between CTGF expression and increasing of VG and AT was analyzed.

RESULTSThere was a significant increase of 24hUalb, KW, and KW/BW from week 1 onward in diabetic rats compared to those in group C (P < 0.05, respectively), diabetic rats also had a significant increase of AG, VG, and AT from week 1 onward. It was also shown that diabetic rats had a thickening of GBM [(245.7 +/- 103.0) nm vs (121.8 +/- 19.1) nm, P < 0.01] and TBM [(767.7 +/- 331.1) nm vs (293.0 +/- 110.5) nm, P < 0.01] at week 8. There was a weak expression for CTGF and p27kip1 in normal glomeruli and tubuli, while a significant increasing expression of CTGF and p27kip1 was found in glomeruli and tubuli in diabetic kidney from week 1 onward (P < 0.05, respectively), and the extent of CTGF expression was positively correlated with AG (r = 0.92, P < 0.05), VG (r = 0.86, P < 0.05), AT (r = 0.94, P < 0.01) and positively correlated with the expression of p27kip1 (r = 0.96, P < 0.01).

CONCLUSIONThe expression of CTGF increases in diabetic rat kidney at the early stage, which might be an important mediator of renal hypertrophy through arresting cell cycling.

Albuminuria ; etiology ; Animals ; Connective Tissue Growth Factor ; Cyclin-Dependent Kinase Inhibitor p27 ; analysis ; Diabetes Mellitus, Experimental ; pathology ; Hypertrophy ; Immediate-Early Proteins ; analysis ; physiology ; Intercellular Signaling Peptides and Proteins ; analysis ; physiology ; Kidney ; pathology ; Male ; Nephrectomy ; Rats ; Rats, Sprague-Dawley ; Streptozocin

OBJECTIVETo observe matrine-induced erythroid differentiation of K562 cells in relation to activation of the apoptotic pathway in vitro.

METHODSK562 cells were cultured in the presence or absence of matrine at different concentrations for 4 days, and the morphological and ultramicrostructural changes of the cells were observed using inverted microscopy and transmission electron microscopy, respectively. The expression of apoptosis-related protein p27kip1 was detected by immunocytochemistry.

RESULTSCompared to untreated K562 cells, the cells treated with matrine at 0.10 g/L exhibited apoptostic characteristics in the cellular morphology and ultramicrostructure, with the expression of p27kip1 protein upregulated in a concentration- and time-dependent manner.

CONCLUSIONMatrine-induced erythroid differentiation of K562 cells is associated with cell apoptosis, and upregulation of p27kip1 protein expression may play a crucial role in the process of apoptosis.

Alkaloids ; pharmacology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; drug effects ; physiology ; Cyclin-Dependent Kinase Inhibitor p27 ; biosynthesis ; Dose-Response Relationship, Drug ; Humans ; Immunohistochemistry ; K562 Cells ; Leukemia, Erythroblastic, Acute ; metabolism ; pathology ; Microscopy, Electron, Transmission ; Quinolizines ; pharmacology ; Signal Transduction ; drug effects ; Time Factors

OBJECTIVETo investigate effects of dahuang zhechong pill ( DHZCP) on the cell cycle and the related signal pathways in vascular smooth muscle cells (VSMCs) stimulated by platelet-derived growth factor (PDGF) with the method of serum pharmacology.

METHODSDNA synthesis in VSMCs was examined by detecting 5'-bromo-2'-deoxyuridine incorporation with the immunocytochemical method. The cycle of VSMCs was evaluated with flow cytometry. Expressions of cyclin D1, p27, protein kinase Cα (PKCα), and phosphorylated extracellular signal regulated kinase 1/2 (ERK1/2) were quantified by Western blot method.

RESULTSDHZCP containing serum significantly inhibited DNA synthesis of PDGF-stimulated VSMCs, arrested the cells in G G(1) phase, modulated the protein expressions of cyclin D D(1) and p27, and suppressed the activation of PKCα and ERK1/2.

CONCLUSIONDHZCP containing serum inhibits VSMCs proliferation via modulating the expressions of cell cycle proteins to arrest the cell in G G(1) phase, which is attributed to, at least in part, suppressing PKCα-ERK1/2 signaling in VSMCs.

Animals ; Aorta, Thoracic ; cytology ; Blood Proteins ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; DNA ; biosynthesis ; Drugs, Chinese Herbal ; pharmacology ; G1 Phase ; drug effects ; physiology ; MAP Kinase Signaling System ; physiology ; Male ; Muscle, Smooth, Vascular ; cytology ; drug effects ; enzymology ; Platelet-Derived Growth Factor ; pharmacology ; Protein Kinase C-alpha ; metabolism ; Rats ; Rats, Sprague-Dawley