OBJECTIVETo explore the possible mechanism(s) of taurine-inhibiting the proliferation of hepatic stellate cells (HSC), this study investigated the effect of taurine on the HSC cell cycle and its regulatory protein expression.

METHODSCell proliferation was assessed by MTT assay. Cell cycle was analyzed by flow cytometry. Cell cycle regulatory protein Cyclin D1 and P21waf1 expression were determined by immunocytochemistry and image-analysis system, and real-time quantitative PCR.

RESULTSHSC proliferation was markedly inhibited when HSC were treated with taurine at concentrations of 5, 10, 20, 30, 40 and 50 mmol/L for 48 hours, and the inhibition rates were 6.7%, 14.4%, 23.3%, 32.2%, 36.7% and 45.6% respectively (P < 0.05-0.01). In the flow cytometry analysis, it was found that taurine could block HSC in the G0/G1 phase from entering the S phase, resulting in more cells in the G0/G1 phase and fewer in the S phase. The percentage of the cells in the G0/G1 phase and the S phase at the dosage of 40 mmol/L were 68.2%+/-1.4% and 26.2+/-1.3% respectively, which was significantly different in comparison to the controls (56.2%+/-1.7% and 38.5%+/-0.8% respectively, P < 0.01). HSC expressed cyclin D1 and P21waf1. Taurine inhibited cyclin D1 expression and induced P21waf1 expression. The cyclin D1 protein and mRNA in the HSC treated with 40 mmol/L taurine were significantly reduced compared with the controls [protein (optical density value): 0.13+/-0.02 versus 0.18+/-0.02, P < 0.01; mRNA: 5776.7+/-3345.0 versus 18,400.6+/-1374.8 copies/10(6) GAPDH, P < 0.01]; and the P21waf1 protein and mRNA were markedly increased compared with the controls [protein (optical density value): 0.19+/-0.02 versus 0.14+/-0.01, P < 0.01; mRNA: 44,866.7+/-3910.7 versus 16,933.3+/-960.9 copies/10(6) GAPDH, P less than 0.05].

CONCLUSIONSCyclin D1 and P21waf1 were cell cycle regulatory proteins in HSC, and taurine can inhibit the HSC cyclin D1 expression and stimulate P21waf1 expression, facilitate arresting cells in G0/G1 phase, and suppress cell proliferation.

Animals ; Cell Cycle Proteins ; biosynthesis ; genetics ; Cell Line ; Cell Proliferation ; Cyclin D1 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Depression, Chemical ; Hepatocytes ; cytology ; Rats ; Taurine ; pharmacology

Carcinoma, Hepatocellular ; pathology ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Humans ; Liver Neoplasms ; pathology ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Transfection ; Tumor Cells, Cultured ; Xeroderma Pigmentosum ; genetics

OBJECTIVETo study the regulatory effect of TGF-beta1 on growth of rhabdomyosarcoma RD cell line.

METHODSAfter various durations of TGF-beta1 treatment, the viability of RD cell line was examined by growth rate measurement, MTT assay and (3)H-thymidine incorporation. The cell cycle was analyzed by flow cytometry. Immunofluorescent staining was used to localize p15, p21 and p27 in RD cell line under laser scanning confocal microscope. The protein and mRNA of p15, p21 and p27 in RD cell line were detected by western blot and reverse transcriptase-polymerase chain reaction respectively.

RESULTSThe viability of RD cell line treated with TGF-beta1 was obviously decreased. RD cell line was arrested in G(1) phase by TGF-beta1. There was increased expression of p21 and p27 in RD cell line with TGF-beta1 treatment at protein and mRNA levels. The expression of p21 in RD cell line was seen in both nucleus and cytoplasm after 24 hours of TGF-beta1 treatment. The expression of p15 showed no obvious changes upon TGF-beta1 treatment.

CONCLUSIONSTGF-beta1 inhibits growth of RD cell line and induces G(1)-arrest. It up-regulates protein and mRNA of p21 and p27 and shows no obvious influence on p15 expression. The growth arrest of RD cell line may result from the up-regulation of p21 and p27 by TGF-beta1.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p15 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p27 ; biosynthesis ; genetics ; G1 Phase ; drug effects ; Humans ; RNA, Messenger ; biosynthesis ; genetics ; Rhabdomyosarcoma ; pathology ; Transforming Growth Factor beta1 ; pharmacology

OBJECTIVETo study the effects of arsenic trioxide (As(2)O(3)) on cell cycle and expression of cyclin dependent kinase inhibitors (CDKIs) in multiple myeloma (MM) cells, and explore its pharmacological mechanism.

METHODSThe DNA content of MM cells line HS-Sultan was analyzed by flow cytometry after exposure to As(2)O(3), the effects on expression of CDKI P15, P16 AND P21 were studied by reverse transcriptase PCR.

RESULTSDNA flow cytometric analysis showed that As(2)O(3) induced most of HS-Sultan cells, arrest at G(0)/G(1) phase and a small fraction at G(2)/M phase and apoptosis occurred mainly in S phase. There was no expression of P15 and P16 mRNA in untreated HS-Sultan cells and 1.0 micromol/L As(2)O(3) could make them expressed after exposed 24 or 48 hours respectively. Expression of P12 mRNA was obviously elevated by As(2)O(3) comparing with that of control.

CONCLUSIONOne of the pharmacological mechanisms of As(2)O(3) is to activate the expression of CDKI P15, P16 and P21, and consequently affect cell proliferation cycle.

Antineoplastic Agents ; pharmacology ; Arsenicals ; pharmacology ; Cell Cycle ; drug effects ; physiology ; Cyclin-Dependent Kinase Inhibitor p15 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p16 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Humans ; Multiple Myeloma ; drug therapy ; metabolism ; pathology ; Oxides ; pharmacology ; RNA, Messenger ; genetics ; Tumor Cells, Cultured

OBJECTIVETo study the effect of overexpression of Smad7 gene on cell proliferation in human bronchial epithelial cell lines.

METHODSHuman bronchial epithelial cell lines, BEP2D and BERP35T2 cells, were cotransfected with the mammalian expression vectors PCISmad7.neo and pMyc-SEAP, the latter was ac-myc cis-acting enhancer element fused with alkaline phosphatase (SEAP) reporter gene. Expression of c-myc, p15 and p21 mRNA was detected by RT-PCR before and after stable transfection of Smad7 into BEP2D and BERP35T2 cells in order to study the regulation of TGF-beta-mediated growth inhibition.

RESULTSAfter BEP2D and BERP35T2 cells transfected with Smad7, the transcriptional activity of c-myc was significantly increased. Smad7 overexpressing cells showed upregulation of c-myc expression and downregulation of p15 and p21 expression, which contributed to the loss of TGF-beta responses in these cells.

CONCLUSIONOverexpression of Smad7 may facilitate cell proliferation by antagonizing TGF-beta-mediated antiproliferative gene responses.

Bronchi ; cytology ; Cell Proliferation ; Cell Transformation, Neoplastic ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p15 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Epithelial Cells ; cytology ; Humans ; Proto-Oncogene Proteins c-myc ; biosynthesis ; genetics ; Signal Transduction ; Smad7 Protein ; biosynthesis ; genetics ; Transfection ; Transforming Growth Factor beta ; biosynthesis ; genetics

This paper was designed to investigate the expression of p53, p21 of A549 cell strains under hypoxic condition and the effect of trichostatin A (TSA), the inhibitor of histone deacetylasel (HDAC1) on their expression. The authors designed 1 normoxia group (control group) and 6 hypoxia groups (experimental group): hypoxia 6 h group (A), TSA+hypoxia 6 h (B), hypoxia 12 h group (C), hypoxia 24 h group (D), TSA+hypoxia 24 h (E), hypoxia 48 h group (F). The expression of HDAC1 in A549 cells was examined by using Western blot and the expression of p53, p21 in A549 cells and the effect of TSA on them were determined by using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The A value expressed by HDAC1 in A549 cell strains was 138+/-11 in the control group, 78+/-4, 86+/-5, 124+/-3, 120+/-9 in experimental groups A, C, D, F, respectively. The A value of the expression of the protein and mRNA of p53 in A549 cell strains were 0.12+/-0.02, 0.62+/-0.02 in the control group, 0.10+/-0.03, 0.32 +/-0.03; 0.11+/-0.01, 0.33+/-0.02; 0.13+/-0.03, 0.58+/-0.01; 0.12+/-0.02, 0.56+/-0.02 in experimental group A, B, D, E, respectively. The A value of the expression of the protein and mRNA of p21 in A549 cell strains were 0.17+/-0.03, 0.62+/-0.03 in the control group, 0.16+/-0.02, 0.50+/-0.02; 0.14+/-0.02, 0.36+/-0.02; 0.15+/-0.03, 0.49+/-0.03; 0.13+/-0.02, 0.33+/-0.02 in experimental groups A, B, D, E, respectively. These results indicate that the expression of HDAC1 is regulated by hypoxia and the effect of TSA is closely related to the expression of P21 under hypoxia condition.
Adenocarcinoma ; metabolism ; pathology ; Cell Hypoxia ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; biosynthesis ; genetics ; Histone Deacetylase Inhibitors ; Humans ; Hydroxamic Acids ; pharmacology ; Lung Neoplasms ; metabolism ; pathology ; RNA, Messenger ; biosynthesis ; genetics ; Tumor Cells, Cultured ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics

OBJECTIVE: To investigate the significance of expression of COX-2, p21, Ki67 and HPV in nasal inverted papilloma. METHOD: Detecting COX-2, p21, Ki-67 in 30 cases of nasal inverted papilloma (NIP), 20 cases of nasal polyps (NP) and 10 cases of normal nasal mucosa (NM) by two step immunohistochemical method, and HPV virus by flow-through hybridization method. RESULT: The positive expression rate of COX-2 and Ki-67 in NIP, NP and NM group was decreased in turn, COX-2 had significant difference in the groups(χ2 = 30.00, P< 0. 05); the positive expression rate of Ki-67 had significant differences between NIP and NM group (χ2 = 8. 533, P<0. 05). The expression of COX-2 in NIP tissues was positively correlate with that of Ki-67 by using Spearman rank correlation analysis (r=0.78, P<0.05). Expression of p21 were not observed in NIP group. The positive rate of HPV was 26. 67% in 30 cases of NIP, all of HPV16 type. CONCLUSION COX-2, Ki-67 and HPV infection have certain correlation with the occurrence of NIP. The occurrence of NIP has relationship with inflammatory reaction mediated by COX-2. Ki-67 can well reflect the proliferation activity of tumor cells, and can be used to measure the proliferation rate of nasal inverted papilloma. The COX-2 and Ki-67 have a synergistic role in the pathogenesis of NIP. p21 has no significant relationship with the incidence of NIP. HPV infection is related to the pathogenesis of NIP, but not as a;major factor in the pathogenesis of NIP.
Case-Control Studies ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; Cyclooxygenase 2 ; biosynthesis ; Humans ; Ki-67 Antigen ; biosynthesis ; Nasal Mucosa ; Nasal Polyps ; Nose Neoplasms ; genetics ; virology ; Papilloma, Inverted ; genetics ; virology ; Papillomavirus Infections

OBJECTIVETo study the growth inhibitory effects of p21WAF1 and p53 overexpression in human lung adenocarcinoma cell line.

METHODSThe p21WAF1 and p53 gene were transfected respectively into a human lung adenocarcinoma cell line, GLC-82. Flow cytometry (FLC), transmission electron microscopy (EM) and TUNEL technique were used to evaluate cell growth and identify apoptosis.

RESULTSThe GLC-82 transfected by p21 plasmid showed increased cell number in G1 phase of cell cycle, decreased proliferation potential and decreased cloning efficiency. Apoptosis have not been detected neither on EM nor by TUNEL technique, whereas the GLC-82 infected by Ad-p53 showed significantly decreased proliferation potential and some of them even died, in addition apoptosis was confirmed by TUNEL technique.

CONCLUSIONThe results indicate that p21WAF1 and p53 can inhibit proliferation; p53 also can induce apoptosis of lung adenocarcinoma cell. Therefore, these two genes should have a wide application in gene therapy of tumors in future.

Adenocarcinoma ; genetics ; metabolism ; pathology ; Apoptosis ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; biosynthesis ; genetics ; Gene Expression ; Humans ; Lung Neoplasms ; genetics ; metabolism ; pathology ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics

OBJECTIVETo focus on the study of the effect on proliferation and apoptosis of human aortic smooth muscle cells (ASMC) by adeno-associated virus (AAV) vector carrying antisense thrombin receptor (ATR) and p21 double gene co-expression system.

METHODSCultured human AMSC was infected with recombinant AAV containing ATR, p21 single gene and AP double gene respectively. The integration and expression of genes were confirmed by semi-quantitative RT-PCR. The anti-proliferation effect was determined by MTT assay. Cell cycle and apoptotic cell counts were measured through Flow Cytometry. The rate of apoptotic cells was examined with acridine orange/ethidium bromide(AO/EB) stain.

RESULTSRT-PCR indicated that the exogenous genes had been integrated into ASMC. The rates of cell survival were decreased by 16.67%, 21.60%, and 29.4% and the cell counts of G0/G1 phase were (61.8 +/- 2.9)%, (82.5 +/- 4.0)%, (80.4 +/- 6.1)% in ATR, p21 and AP group respectively after rAAV infected 4 days. The level and area of apoptotic peak were greater in AP double gene than ATR and p21 single gene. Cell stain indicated that apoptotic cells were (7.2 +/- 3.3)%, (10.7 +/- 5.6)%, and (18.3 +/- 2.7)% in each transgene group compared with (1.5 +/- 0.8)% in control group.

CONCLUSIONAP double gene co-expression system has powerful effect for inhibiting proliferation and inducing apoptosis ASMC than ATR and p21 single gene and that is a superior way for gene therapy to restenosis.

Adenoviruses, Human ; genetics ; Antisense Elements (Genetics) ; Aorta ; cytology ; Apoptosis ; Cell Division ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p21 ; Cyclins ; biosynthesis ; genetics ; Fetus ; Genetic Vectors ; Humans ; Muscle, Smooth, Vascular ; cytology ; Receptors, Thrombin ; biosynthesis ; genetics

OBJECTIVETo study the effect of allicin on cell cycle of human gastric cancer cell lines, MGC-803 and SGC-7901, and its possible mechanisms.

METHODSThe gastric cancer cell lines MGC-803 and SGC-7901 were treated with allicin. Proliferation inhibitory rate was detected by trypan-blue exclusion. Morphologic changes were observed by electron microscopy. The cell cycle was examined by flow cytometry and Giemsa staining. Expression of p21WAF1, p16INK4 protein and mRNA was detected by immunohistochemistry and RT-PCR.

RESULTSThe gastric cancer cells were inhibited after exposure to allicin for 24 hr, The IC50 was 6.4 microg/ml in MGC-803 cells and 7.3 microg/ml in SGC-7901cells. After exposure to allicin of 12 microg/ml for 24 hr, it caused the cytotoxic effect on the cells, including cellular membrane breakagy. After exposure to allicin of 3 microg/ml, 6 microg/ml and 9 microg/ml for 24 hr, compared with the control group, the proportion of cells in the G0/G1 phase was decreased and that in the G2/M phase was increased significantly (P < 0.01). After exposure to allicin of 6 microg/ml for 24 hr, compared with the control group, cell division index was much higher, suggesting that allicin could induce cell arrest in M phase. The expression levels of p21WAF1 and p16INK4 protein and mRNA in MGC-803 cells and p21WAF1 protein and mRNA in SGC-7901 cells were markedly up-regulated.

CONCLUSIONAllicin induce cell arrest of gastric cancer in M phase, which may be related to the up-regulated expression of p21WAF1 and p16INK4 genes.

Adenocarcinoma, Mucinous ; metabolism ; pathology ; ultrastructure ; Antineoplastic Agents, Phytogenic ; pharmacology ; Cell Division ; drug effects ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p16 ; biosynthesis ; genetics ; Cyclin-Dependent Kinase Inhibitor p21 ; biosynthesis ; genetics ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; metabolism ; pathology ; ultrastructure ; Sulfinic Acids ; pharmacology