OBJECTIVETo investigate the correlations between p14(ARF) and E2F-1, and the role of their alterations in the tumorigenesis of the lung cancer in Gejiu and Xuanwei regions in Yunnan Province for providing the important experiment basis in revealing the molecular mechanism and looking for new markers for early diagnosis of lung cancer.

METHODSThe expression of p14(ARF) and E2F-1 was detected at theirs protein level by Immunohistochemistry S-P method in 30 specimens of lung cancer of Gejiu tin miners, 30 specimens of lung cancer of Xuanwei peasants and 20 specimens of normal lung tissue. E2F-1 mRNA was detected by ISH in 25 specimens of lung cancer of Gejiu tin miners, 25 specimens of lung cancer of Xuanwei peasants and 10 specimens of normal lung tissue. The positive signals were quantitatively analysed by HPIAS-100.

RESULTSThe positive unit (PU) of p14(ARF) and E2F-1 was 16.44 +/- 4.85 and 47.39 +/- 5.43 in Gejiu group, and 16.79 +/- 3.55 and 48.15 +/- 9.11 in Xuanwei group. Expression of p14(ARF) and E2F-1 protein in lung cancer of Gejiu and Xuanwei were statistically different compared with that in the normal lung (P < 0.01) respectively; The PU of E2F-1 mRNA was 48.58 +/- 7.75 in Gejiu group, and 49.41 +/- 8.53 in Xuanwei group, which was higher than that in normal tissue group. The differences were significant (P < 0.01). There was positive correlation between the expression of E2F-1 protein and E2F-1 mRNA in Gejiu group, Xuanwei group and normal group (P < 0.01, r = 0.833). The expression of p14(ARF) protein was significantly negatively correlated with the expression of E2F-1 protein (P < 0.01, r = -0.830).

CONCLUSIONThere is the over-expression of E2F-1 gene and the deletion of p14(ARF) gene in the tumorigenesis of the lung cancer in Gejiu and Xuanwei regions in Yunnan Province. Over-expression of E2F-1 protein in lung cancer may be caused by enhanced transcription.

China ; E2F1 Transcription Factor ; genetics ; metabolism ; Female ; Humans ; Lung Neoplasms ; metabolism ; Male ; RNA, Messenger ; genetics ; Tumor Suppressor Protein p14ARF ; metabolism

OBJECTIVETo investigate the roles of activated protein 1 (AP-1) in cell cycle changes on human embryo lung fibroblasts (HELF) induced by benzo (a) pyrene [B (a) P], and relationships between AP-1 and cyclin D1/CDK4-E2F-1/4.

METHODSCells transfected with AP-1 luciferase reporter plasmid (AP-H) were cultured with serum-free RPMI1640 for 48 h, and treated with 2 micromol/L B (a) P for 24 h. AP-1 relative activity was detected by luciferase assay. Changes of cell cycle and the expression of cyclin D1, CDK4 and E2F-1/4 were checked using the flow cytometer and Western blot assay.

RESULTSAfter B (a) P was treated for 24 h, the ratio of G1 phase cells (71 +/- 2)% was decreased to (48 +/- 3)% (P < 0.05), and an increase was observed in the ratio of S phase. AP-1 activity and cyclin D1/E2F-1 expression were increased significantly, but CDK4/E2F-4 expression did not change after B (a) P treatment. When AP-1 activity was inhibited by curcumin, decreases of G1 phase in response to B (a) P treatment were blocked, and overexpression of cyclin D1/E2F-1 was attenuated, but CDK4/E2F-4 expression was not changed significantly.

CONCLUSIONAP-1 is involved in B (a) P induced cell cycle changes, and is the upstream signals of cyclin D1/E2F-1, but not CDK4/E2F-4.

Benzo(a)pyrene ; toxicity ; Cell Cycle ; drug effects ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; E2F1 Transcription Factor ; metabolism ; E2F4 Transcription Factor ; metabolism ; Fibroblasts ; cytology ; metabolism ; Humans ; Transcription Factor AP-1 ; genetics ; metabolism ; Transfection

OBJECTIVE: To determine the dynamic expression of E2F1 in lung of premature rats with hyperoxia-induced chronic lung disease and the relation between E2F1 and pulmonary fibrosis. METHODS: Premature Wistar rats at 21 days gestation were randomly and equally divided into a hyperoxia group and a room air group. The hyperoxia group was continuously exposed to hyperoxia (90%) while the air group in room air. Lung tissues in the 2 groups were obtained at 3, 7 and 14 days after exposing to either room air or hyperoxia. The changes of pulmonary histopathology at different time points were observed by hematoxylin and eosin staining; the severity of pulmonary fibrosis was evaluated; and the expression of E2F1 in lung tissue was detected by immunohistochemistry and Western blot. RESULTS: After 3 days of hyperoxia, no significant interstitial fibrosis was observed; while after 7 days in the hyperoxia group, interstitial fibrosis was observed. These changes became more obvious after 14 days of prolonged hyperoxia exposure. No significant difference in the expressions of E2F1 protein was found between the hyperoxia group and the room air group 3 days postnatally (P>0.05). The expression of E2F1 in the hyperoxia group significantly increased 7 days and 14 days postnatally (P<0.05, P<0.01). CONCLUSION Abnormality of E2F1 expression is involved in the pathological process of the proliferation of lung fibroblasts in hyperoxia-induced chronic lung disease neonatal rats, and it plays an important role in lung fibrosis.
Animals ; Animals, Newborn ; E2F1 Transcription Factor ; metabolism ; Hyperoxia ; metabolism ; pathology ; Immunohistochemistry ; Lung ; pathology ; Lung Diseases ; metabolism ; pathology ; Pulmonary Fibrosis ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar

OBJECTIVETo investigate the variation in expression of ARHI, STAT3 and E2F1 and the correlation among them during carcinogenesis of ovarian serous carcinoma.

METHODSImmunohistochemical staining was used to detect the expression of ARHI, STAT3 and E2F1 in samples of 25 normal ovaries, 35 ovarian serous cystadenomas, 18 borderline serous cystadenomas and 56 ovarian serous carcinomas. The variation in expression of the three genes and relationship among them were analyzed.

RESULTSARHI expression was detected in 22 of 25 (88.0%) normal ovaries and 30 of 35 (85.7%) cystadenomas, but only in 10 of 18 (55.6%) borderline serous cystadenomas and 22 of 56 (39.3%) ovarian serous carcinomas, significantly lower than that in the normal ovaries and ovarian serous cystadenomas (P < 0.05). STAT3 expression was found in 14 of 18 (77.8%) borderline serous cystadenomas and 49 of 56 (87.5%) ovarian serous carcinomas, significantly higher than that in the normal ovaries and ovarian serous cystadenomas (P < 0.05). To compare with E2F1 expression in the normal ovaries, serous cystadenomas and borderline serous cystadenomas, E2F1 expression in 46 of 56 (82.1%) ovarian serous carcinomas was significantly higher (P < 0.05). It was found that the expression of ARHI was inversely correlated with that of STAT3 and E2F1.

CONCLUSIONOur findings indicate that ARHI expression is down-regulated, but STAT3 and E2F1 expressions are up-regulated, with an inverse correlation between ARHI and STAT3 in the carcinogenesis of ovarian serous carcinoma.

Adult ; Aged ; Cystadenocarcinoma, Serous ; metabolism ; pathology ; Cystadenoma, Serous ; metabolism ; pathology ; E2F1 Transcription Factor ; metabolism ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Immunohistochemistry ; Middle Aged ; Ovarian Neoplasms ; metabolism ; pathology ; Ovary ; metabolism ; pathology ; STAT3 Transcription Factor ; metabolism ; rho GTP-Binding Proteins ; metabolism

OBJECTIVETo study the role of E2F1/4 pathway in vitamin C reversing benzo (a) pyrene [B (a) P]-induced changes of cell cycle in human embryo lung fibroblasts (HELF) and the relationship between E2F1 and cyclin D1/CDK4.

METHODSThe stable transfectants, HELF transfected with antisense cyclin D1 and antisense CDK4, were established to detect the relationship of signaling pathway. Cells were cultured and pretreated with vitamin C before stimulation with B (a) P for 24 hours. The expression levels of cyclin D1, CDK4, E2F1 and E2F4 were determined by Western blot and the band intensity was analysed as the relative value to control by using the Gel-Pro 3.0 software. Flow Cytometric Analysis was employed to detect the distributions of cell cycle.

RESULTSB (a) P significantly elevated the expression levels of cyclin D1, CDK4, E2F1 and E2F4 in HELF cells. Vitamin C decreased the expression levels of above proteins in B (a) P-stimulated HELF cells. The expression levels of these proteins in B (a) P-treated above transfectants were lower than those in B (a) P-treated HELF cells. The expression levels of above proteins with vitamin C combined with antisense cyclin D1 were decreased as compared to those with antisense cyclin D1 alone. B (a) P increased the percentage of S phase as compared to the controls [(41.1 +/- 0.2)% vs (33.5 +/- 3.2)%, P < 0.05]. Both vitamin C [(33.2 +/- 0.6)% vs (41.1 +/- 0.2)%, P < 0.05] and antisense cyclin D1 [(31.2 +/- 1.3)% vs (41.1 +/- 0.2)%, P < 0.05] suppressed the changes of cell cycle induced by B (a) P. Vitamin C combined with antisense CDK4 markedly suppressed B (a) P-induced changes of cell cycle as compared to those with antisense CDK4 alone.

CONCLUSIONVitamin C might reserve the B (a) P-induced changes of cell cycle via intracellular signaling pathway of cyclin D1-CDK4/E2F-1/4.

Ascorbic Acid ; pharmacology ; Benzo(a)pyrene ; antagonists & inhibitors ; toxicity ; Cell Cycle ; drug effects ; Cyclin D1 ; metabolism ; E2F1 Transcription Factor ; metabolism ; E2F4 Transcription Factor ; metabolism ; Humans ; Lung ; cytology ; embryology ; Signal Transduction

OBJECTIVETo investigate the reverse effect of all-trans retinoic acid (ATRA) on Benzo (a) pyrene (B (a) P)-induced cyclin D1, CDK4, E2F-1 and E2F-4 expression and cell cycle progression in human embryo lung fibroblast (HELF).

METHODSAfter HELF cells was treated with ATRA, they were exposed to 2 micromol/L of B (a) P. Western blotting was employed to detect protein expression level; the RNA transfection techniques was used to investigate ATRA-induced signal pathway; flow cytometry was used to detect cell cycle progression.

RESULTAfter treatment with 2 micromol/L B (a) P for 24 h, the expression of cyclin D1 and E2F-1 were both increased significantly in HELF; the expression of E2F-4 and CDK4 were not changed markedly; pretreatment with 0.1 micromol/L ATRA for 24 h could efficiently decrease B (a) P-induced overexpression of cyclin D1 and E2F-1; stimulation to antisense cyclin D1 or antisense CDK4 by B (a) P could significantly impair E2F-1 up-regulation; pretreatment with ATRA, cells with antisense cyclin D1 or antisense CDK4 showed a less decrease in B (a) P-induced overexpression of E2F-1 compared to similarly treated control cells; flow cytometry analysis showed B (a) P promoted cell cycle progression from G(1) phase to S phase, while pretreatment with ATRA could inhibit B (a) P-induced cell cycle progression by an accumulation of cells in the G(1) phase.

CONCLUSIONATRA could block B (a) P-induced cell cycle promotion through cyclin D1/E2F-1 pathway in HELF.

Benzo(a)pyrene ; toxicity ; Cell Cycle ; drug effects ; Cells, Cultured ; Cyclin D1 ; metabolism ; E2F1 Transcription Factor ; metabolism ; Fibroblasts ; cytology ; drug effects ; metabolism ; Flow Cytometry ; Humans ; Lung ; cytology ; metabolism ; Signal Transduction ; drug effects ; Tretinoin ; pharmacology

OBJECTIVETo investigate the expression of pRb and E2F-1, and the association between their expression and the activity of telomerase (hTERT) or cyclin E in human ameloblastoma (AB), and to explore the clinical biological characteristics of AB.

METHODSThe expressions of pRb, E2F-1, cyclin E and hTERT mRNA in human AB were detected by in situ hybridization or immunohistochemistry (SP method).

RESULTSThe positive expression ratio of pRb in the cell nucleus of AB was 20.4% (11/54). The positive ratio of E2F-1, cyclin E and hTERT mRNA was 92.6% (50/54), 66.7% (36/54) and 94.4% (51/54), respectively. With AB recurrence and malignant transformation, the expression of hTERT, E2F-1, cyclin E was up-regulated. hTERT and cyclin E or E2F-1 mRNA had high positive relation (Spearsman'r(s) = 1.000, P = 0.0001).

CONCLUSIONSThe regulatory pathway of Rb/E2F-1 is associated with the cell proliferation and in differentiation of AB. The activity or release of telomerase may be related to the lower expression of Rb and higher expression of E2F-1, and is up-regulated in G(1) late phase by cyclin E.

Adolescent ; Adult ; Aged ; Ameloblastoma ; metabolism ; pathology ; Child ; Cyclin E ; biosynthesis ; E2F1 Transcription Factor ; biosynthesis ; Female ; Humans ; Jaw Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; RNA, Messenger ; biosynthesis ; Retinoblastoma Protein ; biosynthesis ; Telomerase ; genetics ; metabolism

OBJECTIVETo investigate the effect of EBV immediate-early protein Zta on cell cycle of Daudi cells and the involved mechanisms.

METHODSThe expression vector encoding Zta was constructed and electroporated into Daudi cells. Flow cytometric analysis was used to detect the cell cycle, Western blot to the protein levels of p21, Rb and E2F-1.

RESULTSThe vector was constructed successfully, the expression of Zta protein inhibited the proliferation of Daudi cells and promoted cell cycle from G(0)/G(1) phase \[(30.0 ± 3.4)%\] to S phase \[(47.7 ± 1.1)%\]. Meanwhile, Rb expression was significantly downregulated, E2F-1 and p21 expression upregulated by Zta.

CONCLUSIONZta could promote G(0)/G(1) phase to S phase transition in Daudi cells, which might be associated with the reduced expression of Rb and increased expression of E2F-1 and p21 protein.

Cell Cycle ; genetics ; Cell Division ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; E2F1 Transcription Factor ; metabolism ; Genetic Vectors ; Herpesvirus 4, Human ; genetics ; Humans ; Immediate-Early Proteins ; genetics ; Retinoblastoma Protein ; metabolism ; Trans-Activators ; genetics ; Transcriptional Activation ; Viral Proteins ; genetics

OBJECTIVETo investigate the regulatory effect and significance of transcription factor E2F1 on X-ray repair cross2 complementing 1 (XRCC1).

METHODSSaos2 cells were transfected with the E2F1 expression vectors (tet-E2F1) and mutated E2F1 expression vectors (tet-132E). XRCC1 promotor luciferase reporter vector was constructed and transfected into Saos2 cells together with E2F1, E2F2, E2F3 and E2F4 expression vectors at different amount. The cells were collected 36 hours post-transfection for luciferase assays and absorbance was read at 570 nm.

RESULTSCotransfection of increasing amounts of E2F1 expression vector with the XRCC1 promoter-luciferase reporter caused a dose-dependent increase in luciferase activation. In contrast, DNA binding incompetent E2F1 (132E) could not activate the XRCC1 promoter-luciferase reporter.

CONCLUSIONE2F1 could upregulate endogenous XRCC1 expression and stimulate the XRCC1 promoter.

Cell Line, Tumor ; DNA-Binding Proteins ; genetics ; metabolism ; E2F1 Transcription Factor ; genetics ; metabolism ; Gene Expression ; Genes, Reporter ; Humans ; Promoter Regions, Genetic ; Protein Binding ; Up-Regulation ; X-ray Repair Cross Complementing Protein 1

OBJECTIVEE2F-1 and Rb are involved in cell cycle regulation. This study was to illustrate the mechanism of transformation from benign papillomatosis to ductal carcinoma in situ (DCIS) of the breast in relation to E2F-1 and Rb expression.

METHODSIn situ hybridization (ISH) was used to determinate the expression of E2F-1 and Rb mRNA of mild papillomatosis (MP, n = 40), severe papillomatosis (SP, n = 40) and DCIS (n = 40). Immunohistochemistry (IHC) was used to examine the expression of E2F-1 and Rb protein.

RESULTSThe positive rate of E2F-1 mRNA expression in MP, SP and DCIS was 17.5%, 45.0% and 80.0%, and that of E2F-1 protein expression was 20.0%, 47.5% and 77.5%, respectively. There were significant differences among the three groups (P < 0.01), and between any two groups (P < 0.01). The positive rate of Rb mRNA expression in MP, SP and DCIS was 90.0%, 50.5% and 20.0%, and that of Rb protein expression was 85.0%, 52.5% and 22.5%, respectively, with statistically significant difference similar with that of E2F-1. With the progression of papillomatosis to DCIS, the expression of E2F-1 mRNA and protein increased, while that of Rb decreased. The protein expression by IHC was positively correlated with the mRNA expression by ISH. However, that of E2F-1 was negatively correlated with Rb.

CONCLUSIONE2F-1 and Rb might provide a valuable basis for screening high risk papillomatosis and new target of gene therapy for pre-cancerous lesions of the breast.

Breast Neoplasms ; genetics ; metabolism ; Carcinoma, Intraductal, Noninfiltrating ; genetics ; metabolism ; Cell Cycle Proteins ; biosynthesis ; genetics ; DNA-Binding Proteins ; biosynthesis ; genetics ; E2F Transcription Factors ; E2F1 Transcription Factor ; Female ; Gene Expression Regulation, Neoplastic ; Genes, Retinoblastoma ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Papilloma ; genetics ; metabolism ; Precancerous Conditions ; genetics ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Retinoblastoma Protein ; biosynthesis ; genetics ; Transcription Factors ; biosynthesis ; genetics