OBJECTIVE: To establish a SD rat model of vulvar squamous intraepithelial lesions. METHODS: Seventy female SD rats were randomized into 4 groups, namely the blank control group (=10), mechanical irritation group (=10), acetone solution group (=10), and mechanical irritation with DMBA acetone solution group (=40, model group), and the corresponding treatments were administered 3 times a week for 14 weeks. The changes of the vulvar skin of the rats were observed regularly until the 18th week. The expression of mutant p53 (mtp53) and vascular endothelial growth factor (VEGF) proteins were detected using immunohistochemistry and Western blotting, and the expressions of mtp53 and VEGF mRNA were detected with qRT- PCR in the blank control group and model group. RESULTS: No significant differences were found in the morphological or histopathological changes of the skin among the blank control group, mechanical irritation group and acetone solution group. In the model group, low-grade squamous intraepithelial lesions (LSIL) occurred in 28 rats (70%) and high-grade squamous intraepithelial lesions (HSIL) in 11 rats (27.5%) at 14 weeks, with a success rate of 97.5% in inducing vulvar squamous intraepithelial lesions. Compared with the blank control group, the rats in the model group showed significantly increased expressions of mtp53 and VEGF at both the protein level ( < 0.05) and the mRNA level ( < 0.05). CONCLUSIONS DMBA in acetone solution combined with mechanical irritation can induce vulvar squamous intraepithelial lesions in female SD rats.
9,10-Dimethyl-1,2-benzanthracene ; Acetone ; Animals ; Blotting, Western ; Carcinogens ; Disease Models, Animal ; Female ; Friction ; Immunohistochemistry ; Precancerous Conditions ; chemically induced ; metabolism ; pathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Skin ; pathology ; Solvents ; Tumor Suppressor Protein p53 ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism ; Vulvar Neoplasms ; chemically induced ; metabolism ; pathology

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent and prevalent nitrosamine procarcinogen found in cigarette smoke. The aim of this work is to study alterations in peroxiredoxin (Prx) expression induced by NNK during carcinogenesis. Characterization of Prx genes from hamster was performed using bioinformatics. V79 cells were induced with different concentrations of NNK (0.1-0.4 mg/mL), and the expression levels of six Prx genes (Prx1-Prx6) were measured by qRT-PCR 24 h following NNK treatment. Prx gene expression was induced by NNK stress, and the highest transcription levels were induced by over 20.42-fold relative to that of the control. NNK induced alterations in Prx expression over the course of lung cancer, which means Prxs may play important roles in ROS detoxification under NNK stress and their functions are complementary.
Animals ; Carcinogens ; administration & dosage ; toxicity ; Cell Line ; Cell Survival ; Cricetinae ; Cricetulus ; Dose-Response Relationship, Drug ; Gene Expression Regulation ; drug effects ; Nitrosamines ; administration & dosage ; toxicity ; Peroxiredoxins ; genetics ; metabolism

OBJECTIVETo study the expression of nNOS and ultrastructural changes in the penile tissue of rats with prolactinoma-induced erectile dysfunction (ED).

METHODSWe established the model of prolactinoma in 20 male Westar rats by peritoneal injection of diethylstilbestrol (DES) and treated the control rats with normal saline (n = 10) or sterilized arachis oil (n = 10). After 8 weeks, we performed the apomorphine test and measured the weight of the pituitary gland and the levels of serum prolactin (PRL) and testosterone (T) to confirm the successful construction of the prolactinoma-induced ED model. Then we determined the expression of nNOS in the penile tissue by immunohistochemistry and examined the ultrastructural changes of the penile cavernosum under the transmission electron microscope.

RESULTSThe prolactinoma-induced ED model was successfully established in 15 rats. The weight of the pituitary gland was significantly increased in the rats treated with DES as compared with the normal saline and sterilized arachis oil controls ([46.7 ± 15.5] vs [11.7 ± 2.4] and [12.4 ± 2.3] mg, both P < 0.05). The level of serum PRL was markedly higher while that of T remarkably lower in the former than in the latter two groups ([1,744.9 ± 304.5] vs [11.5 ± 2.4] and [10.6 ± 1.9] ng/ml, both P < 0.0l; [1.54 ± 0.46] vs [3.11 ± 1.08] and [3.04 ± 1.11] ng/ml, both P < 0.05). The rate of penile erection was significantly reduced in the prolactinoma-induced ED model rats in comparison with the normal saline and arachis oil controls (16.7% vs 100% and 87.5%, both P < 0.05), and so was the expression of nNOS in the penile tissue (0.024 ± 0.011 vs 0.066 ± 0.019 and 0.058 ± 0.021, both P < 0.05). Transmission electron microscopy manifested significant ultrastructural changes in the endothelial and smooth muscle cells of the cavernous tissue in the prolactinoma-induced ED models.

CONCLUSIONThe ultrastructural changes of the penile cavernous tissue and the reduced expression of nNOS in penile tissue may be the most important mechanisms of prolactinoma-induced ED in rats.

Animals ; Apomorphine ; Carcinogens ; Diethylstilbestrol ; Erectile Dysfunction ; etiology ; Humans ; Male ; Myocytes, Smooth Muscle ; ultrastructure ; Nitric Oxide Synthase Type I ; metabolism ; Organ Size ; Penile Erection ; Penis ; enzymology ; ultrastructure ; Pituitary Neoplasms ; chemically induced ; complications ; Prolactin ; blood ; Prolactinoma ; chemically induced ; complications ; Rats ; Rats, Wistar ; Testosterone ; blood

OBJECTIVETo investigate the changes of miR-155 and its target genes in colitis-associated carcinogenesis.

METHODSColitis-associated colon cancer was induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) in C57BL/6 mice. Mice of three different stages during the development of colon cancer were obtained, named AD1, AD2 and AD3, respectively. A control group of mice without any treatment and a DSS only group representing chronic inflammation without cancer were set up as well. Colon tissue was collected and expression of miR-155 in the colon tissues was measured by real-time fluorescent quantitative PCR. TargetScan and PicTar were used to predict potential target genes of miR-155, which were then preliminarily screened with our gene expression microarray database of AOM-DSS mouse model. Regular PCR was used to confirm the changes of the expression of these potential target genes in AOM-DSS mouse model.

RESULTSColitis-associated colon cancer was effectively induced by azoxymethane and dextran sulfate sodium in C57BL/6 mice. Histological examination revealed that the evolution process was sequentially from normal, mild dysplasia, moderate dysplasia, and severe dysplasia to adenocarcinoma in the AOM-DSS mouse model. The level of miR-155 was gradually elevated with the formation of colitis-associated colon cancer. There was no significant difference between the levels of miR-155 expression in the DSS group (0.005 6 ± 0.003 7) and control group (0.012 0 ± 0.005 1) (P > 0.05), but the level of miR-155 in the AD3 group (0.054 4 ± 0.027 0) was significantly higher than that of the DSS group (0.005 6 ± 0.003 7)(P < 0.01). No significant change of miR-155 expression was found in the DSS only group. The relative expression levels of miR-155 in the control group, DSS only group and AD3 group were 0.012 0 ± 0.005 1, 0.005 6 ± 0.003 7, 0.054 4 ± 0.027 0, respectively. Data analysis with the gene expression microarray showed that Tle4, Kcna1, Itk, Bcorl1, Cacna1c, Rspo2 and Foxo3 were potential target genes of miR-155 in the AOM-DSS mouse model. Changes of Kcna1 and Cacna1c in the AOM-DSS mouse model were validated to be consistent with the changes obtained with the gene expression microarray.

CONCLUSIONThe up-regulation of miR-155 is related to colitis-associated carcinogenesis, but is irrelevant to chronic inflammation in the mouse model.

Adenocarcinoma ; chemically induced ; genetics ; metabolism ; Animals ; Azoxymethane ; toxicity ; Carcinogens ; toxicity ; Cocarcinogenesis ; Colitis ; chemically induced ; genetics ; metabolism ; Colon ; metabolism ; Colonic Neoplasms ; chemically induced ; genetics ; metabolism ; Dextran Sulfate ; toxicity ; Gene Expression Profiling ; Male ; Mice ; Mice, Inbred C57BL ; MicroRNAs ; metabolism ; Precancerous Conditions ; chemically induced ; genetics ; metabolism ; Up-Regulation

OBJECTIVEThe present paper aims to investigate the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and N-nitrosodiethylamine (DEN) on tumorigenesis and its potential mechanism.

METHODSThe potentials of TCDD and DEN in separation or in combination to induce malignant transformation were tested in Balb/c 3T3 cells by using a cell transformation assay method. The possible mechanism of observed effects was studied further by adding α-naphthoflavone (α-NF), a competitive binding agent of TCDD, to the Aryl hydrocarbon receptor (AhR) pathway. The mRNA expressions of Cyp1a1 and Cyp2a5 gene in Balb/c 3T3 cells treated by DEN and TCDD in separation or in combination with or without presence of α-NF were measured with fluorescence quantification RT-PCR technique.

RESULTSThe cell transformation frequency (TF) was significantly higher in case of induction with TCDD in combination with DEN, as compared to that with either TCDD or DEN alone. These effects were not inhibited via α-NF. The mRNA expression levels of both Cyp1a1 and Cyp2a5 were enhanced by TCDD treatment alone, but this inducible effect was blocked in cells treated by TCDD and DEN in combination.

CONCLUSIONTCDD and DEN had a significant synergistic effect on tumorigenesis when they were used in combination. AhR pathway may not be the key mechanism of this synergistic effect. Thus, it is necessary to further test the potential mechanism involved in cancer development.

3T3 Cells ; Animals ; Base Sequence ; Carcinogens ; toxicity ; Cell Transformation, Neoplastic ; Cytochrome P-450 Enzyme System ; genetics ; DNA Primers ; Diethylnitrosamine ; toxicity ; Drug Synergism ; Mice ; Mice, Inbred BALB C ; Polychlorinated Dibenzodioxins ; toxicity ; RNA, Messenger ; genetics ; Real-Time Polymerase Chain Reaction ; Receptors, Aryl Hydrocarbon ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the main proteinases responsible for CD16b shedding under different stimulators.

METHODSHEK293 cell line stably expressing CD16b was constructed by lentivirus system. The cell line was then overexpressed with a disintegrin and metalloproteinase 10 (ADAM10) or ADAM17, suppressed with short hairpin RNA of ADAM10 or ADAM17, and reconstituted with ADAM10 or ADAM17, respectively. After each treatment, the cell line was stimulated with ionomycin or phorbol 12-myristate- 13-acetate (PMA) for 12 hours. The soluble CD16b released from cell membrane was detected by immunoprecipition and immunoblot. Quantitation was then implemented to compare the amount of soluble CD16b in cell supernatant after stimulation.

RESULTSHEK293 cell line stably expressing CD16b was successfully established. When CD16b expressing cell line was overexpressed with ADAM10, shedding of CD16b was increased after stimulation with ionomycin but not PMA; when the cell line overexpressed with ADAM17, shedding of CD16b was increased after stimulation with PMA but not ionomycin. Similarly, when ADAM10 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with ionomycin; when ADAM17 was suppressed by short hairpin RNA, CD16b shedding was decreased after stimulation with PMA. The shedding of CD16b was increased again when CD16b expressing cell line was reconstituted with ADAM10 and stimulated by ionomycin or reconstituted with ADAM17 and stimulated by PMA.

CONCLUSIONSBoth ADAM10 and ADAM17 could shed CD16b, but they possess differed preferences. ADAM10 is the main sheddase under stimulation of ionomycin, while ADAM17 is the main sheddase under stimulation of PMA.

ADAM Proteins ; genetics ; metabolism ; physiology ; ADAM10 Protein ; ADAM17 Protein ; Amyloid Precursor Protein Secretases ; genetics ; metabolism ; physiology ; Calcium Ionophores ; pharmacology ; Carcinogens ; pharmacology ; Cells, Cultured ; Drug Evaluation, Preclinical ; GPI-Linked Proteins ; metabolism ; Gene Knockdown Techniques ; HEK293 Cells ; Humans ; Ionomycin ; pharmacology ; Membrane Proteins ; genetics ; metabolism ; physiology ; Protein Processing, Post-Translational ; drug effects ; Protein Transport ; drug effects ; Proteolysis ; drug effects ; Receptors, IgG ; metabolism ; Tetradecanoylphorbol Acetate ; pharmacology ; Transfection

OBJECTIVETo investigate the effect of sphingosine kinase 1 (SphK1) on the proliferation, apoptosis, migration and invasion of colon cancer TH-29 cells and to explore its molecular mechanisms.

METHODSPhorbol 12-myristate 13-acetate (PMA) was used to induce the activity of SphK1 and N, N-dimethylsphingosine (DMS) was used to suppress the activity of SphK1. Cell prolieration and apoptosis were detected by MTT assay and flow cytometry, respectively. The migration and invasion capabilities of the cells were assessed in Transwell chambers. The activity of SphK1 was assayed by autoradiography. Western blot was used to evaluate the protein expression of SphK1, p38, phosphorylated p38 (p-p38) and SAPK/JNK.

RESULTSPMA and DMS were able to induce and suppress the activity and protein expression of SphK1 in a time-dependent manner, respectively. PMA enhanced and DMS suppressed the cell viability in a time- and dose-dependent manner. Being treated with 100 nmol/L PMA or 50 µmol/L DMS for 0, 6, 12, 24 h, the cell apoptosis rates of PMA group were (9.35 ± 0.84)%, (7.61 ± 0.48)%, (5.53 ± 0.76)% and (0.56 ± 0.33)%, contrastly, that of DMS group were (9.18 ± 0.94)%, (12.06 ± 1.41)%, (19.80 ± 2.36)% and (31.85 ± 3.60)%, respectively. Compared with the control group, the cell migration and invasion capabilities of the PMA group were significantly enhanced, and that of the DMS group were significantly suppressed. The migration cell number of control, PMA and DMS groups were 68.75 ± 6.15, 109.33 ± 11.63 and 10.83 ± 2.48, the invasion cell number of control, PMA and DMS groups were 55.42 ± 4.50, 90.58 ± 7.06 and 9.58 ± 2.39, respectively. With the elevating activity and expression of SphK1, the protein expressions of p38, p-p38 and SAPK/JNK were strikingly suppressed. On the contrary, after treating with DMS the protein expressions of p38, p-p38 and SAPK/JNK were enhanced.

CONCLUSIONSSphK1 potently enhances the prolieration, migration and invasion of colon cancer HT-29 cells, meanwhile suppresses the cell apoptosis. The suppressing of the p38 and SAPK/JNK signalling pathways may be one of its molecular mechanisms.

Apoptosis ; drug effects ; Carcinogens ; administration & dosage ; pharmacology ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; administration & dosage ; pharmacology ; HT29 Cells ; Humans ; MAP Kinase Kinase 4 ; metabolism ; Neoplasm Invasiveness ; Phosphorylation ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; physiology ; Sphingosine ; administration & dosage ; analogs & derivatives ; pharmacology ; Tetradecanoylphorbol Acetate ; administration & dosage ; analogs & derivatives ; pharmacology ; Time Factors ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo investigate the expression variation of RAR-β2, RASSF1A, and CDKN2A gene in the process of nickel-induced carcinogenesis.

METHODSNickel subsulfide (Ni(3)S(2)) at dose of 10 mg was given to Wistar rats by intramuscular injection. The mRNA expression of the three genes in induced tumors and their lung metastasis were examined by Real-time PCR. The methylation status of the 5' region of these genes were detected by Quantitative Real-time methylation specific PCR.

RESULTSThe mRNA expressions of the three genes both in muscle and lung tumor were decreased distinctly in comparison with normal tissue. But hypermethylation was found only in muscle tumor.

CONCLUSIONThese findings suggest that loss of function or decrease of RAR-β2, RASSF1A, and CDKN2A, as well as the hypermethylation of 5' region of these genes, are related with nickel exposure.

Animals ; Carcinogens ; toxicity ; CpG Islands ; Cyclin-Dependent Kinase Inhibitor p16 ; genetics ; metabolism ; DNA Methylation ; Gene Expression Regulation, Neoplastic ; drug effects ; Lung Neoplasms ; chemically induced ; metabolism ; Male ; Muscle Neoplasms ; chemically induced ; metabolism ; Nickel ; toxicity ; Rats ; Rats, Wistar ; Receptors, Retinoic Acid ; genetics ; metabolism ; Tumor Suppressor Proteins ; genetics ; metabolism

Many epidemiologic and clinical studies have indicated that the frequency of breast cancer was lower in parous women than in nulliparous women. Moreover, the incidence of breast cancer has been reported to be lower in women with early childbirth than in women with late childbirth. To verify the effect of childbirth and the age at first childbirth on carcinogenesis and progression of breast cancer, we induced breast cancer by 7,12-dimethylbenanthracene (DMBA) in 120 female Sprague-Dawley (SD) rats, and divided them into control or experimental (DMBA-treated) nulliparous, early childbirth, and late childbirth groups to observe the incidence, latency, and size of breast cancer. Argyrophilic nucleolar organizer regions (AgNOR) count and the expression of C-erbB-2, proliferating cell nuclear antigen (PCNA), Ki-67, and minichromosome maintenance protein 2 (MCM2) in breast cancer tissues were detected by immunohistochemistry. The breast cancer incidences were 95.0%, 16.7%, and 58.8% in the experimental nulliparous, early childbirth, and late childbirth groups, respectively (all P < 0.05). Between any two of these groups, the latency was significantly different, but tumor size was similar. AgNOR count and the expression of C-erbB-2, PCNA, Ki-67, and MCM2 were significantly higher in the experimental nulliparous group than in the experimental early or late childbirth groups (P < 0.05), but no significant differences were observed between the latter two groups. Taken together, the results suggest that childbirth, especially early childbirth, can reduce the incidence and postpone the onset of DMBA-induced breast cancer.
9,10-Dimethyl-1,2-benzanthracene ; Animals ; Antigens, Nuclear ; metabolism ; Carcinogens ; Cell Transformation, Neoplastic ; Female ; Ki-67 Antigen ; metabolism ; Mammary Neoplasms, Experimental ; chemically induced ; metabolism ; pathology ; physiopathology ; Minichromosome Maintenance Complex Component 2 ; Nuclear Proteins ; metabolism ; Parity ; Pregnancy ; Proliferating Cell Nuclear Antigen ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptor, ErbB-2 ; metabolism ; Tumor Burden

Epidermal growth factor receptor (EGFR) is a classic protein tyrosine kinase receptor, which plays an important role in cell proliferation, survival, adhesion, differentiation and apoptosis. Abnormality of EGFR and its signaling are closely associated with tumor initiation and development. Many environmental physical and chemical agents can interfere with EGFR and its signal transduction pathways via affecting its phosphorylation, conformation and function, or distribution on cell membrane, finally influencing gene expression and cell fate. This review focuses on the recent progress of above aspects for further understanding of epigenetic mechanisms of cellular stress and carcinogenesis related with environmental agents.
Carcinogens ; Environmental Exposure ; adverse effects ; Environmental Pollutants ; adverse effects ; Humans ; Phosphorylation ; Receptor, Epidermal Growth Factor ; drug effects ; metabolism ; Signal Transduction ; drug effects