Gastric cancer(GC), one of the most common malignancies worldwide, seriously threatens human health due to its high morbidity and mortality. Precancerous lesion of gastric cancer(PLGC) is a critical stage for preventing the occurrence of gastric cancer, and PLGC therapy has frequently been investigated in clinical research. Exploring the proper animal modeling methods is necessary since animal experiment acts as the main avenue of the research on GC treatment. At present, N-methyl-N'-nitro-N-nitroso-guanidine(MNNG) serves as a common chemical inducer for the rat model of GC and PLGC. In this study, MNNG-based methods for modeling PLGC rats in related papers were summarized, and the applications and effects of these methods were demonstrated by examples. Additionally, the advantages, disadvantages, and precautions of various modeling methods were briefly reviewed, and the experience of this research group in exploring modeling methods was shared. This study is expected to provide a reference for the establishment of MNNG-induced PLGC animal model, and a model support for the following studies on PLGC.
Animals ; Gastric Mucosa ; Methylnitronitrosoguanidine/toxicity* ; Precancerous Conditions/chemically induced* ; Rats ; Stomach Neoplasms/drug therapy*

OBJECTIVETo further explore the carcinogenic activity of Sterigmatocystin (ST) and the possible synergistic carcinogenic effect of deoxynivalenol (DON) in NIH mice.

METHODSNIH mice were randomly divided into 6 groups, 30 in each. Five groups of mice were given by gastric intubation ST 3 microg/kg, ST 30 microg/kg, ST 3 microg/kg + DON 1.5 microg/kg, ST 30 microg/kg + DON 1.5 microg/kg and DON 1.5 microg/kg respectively, 3 times a week for 24 weeks. The remaining group of mice was given normal saline accordingly, serving as control. All mice were fed with HPLC-confirmed mycotoxin-free food, analysis. The mice were killed and pathologically examined at 58th and 74th weeks.

RESULTSNo pathological changes were found in the control group of mice. Adenocarcinoma of lung was observed in 25.0%, 41.7%, 62.5%, 69.2% and 37.5% of mice given ST 3 microg/kg, ST 30 microg/kg, ST 3 microg/kg + DON 1.5 microg/kg, ST 30 microg/kg + DON 1.5 microg/kg and DON 1.5 microg/kg, respectively. In addition, dysplasia of glandular stomach was detected in 50.0%, 58.3%, 37.5%, 53.8% and 25.0% of mice similarly treated.

CONCLUSIONOral administration of ST or DON can induce adenocarcinoma in lung and dysplasia of glandular stomach in NIH mice. There is synergistic carcinogenic effect when both ST and DON are given.

Adenocarcinoma ; chemically induced ; pathology ; Animals ; Female ; Gastric Mucosa ; pathology ; Lung Neoplasms ; chemically induced ; pathology ; Male ; Mice ; Precancerous Conditions ; chemically induced ; pathology ; Sterigmatocystin ; toxicity ; Trichothecenes ; toxicity

Iron is essential for the growth of all living cells. One of the most important intracellular roles of iron is the activation of ribonucleotide reductase, which is indispensible to the production of deoxyribonucleotide necessary for DNA synthesis. Deferoxamine (DFO) is an iron chelating agent and has been known to have an antiproliferative effect in various malignant cells including hepatocellular carcinoma and the effect seems to be related to depletion of iron. This study was undertaken to investigate the effect of DFO on preneoplastic lesions in chemically induced hepatocarcinogenesis. The resistant hepatocyte model was used and Sprague Dawley rats were divided into the following groups; I: normal control, II: carcinogen administered group, III: carcinogen and DFO administered group. Rats were sacrificed at 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks and 8 weeks after partial hepatectomy (PH). DFO (50 mg/kg/day, I.P.) was daily injected from 3 weeks before administration of carcinogen to the time when rats were sacrificed. Hepatic iron content was higher in group II than in group III, especially at 3 days and 1 week after PH. Hyperplastic lesions of resistant hepatocytes were less well developed in group III than in group II. Bromodeoxyuridine labelling indices of oval cells and hyperplastic lesions of resistant hepatocytes were higher in group II than in group III except for rats examined at 3 days after PH. The results suggest that DFO has an antiproliferative effect on preneoplastic lesions in hepatocarcinogenesis and it might be related to reduction of the hepatic iron.
Animal ; Deferoxamine/*pharmacology ; Diethylnitrosamine ; Liver Neoplasms, Experimental/chemically induced/*prevention & control ; Male ; Precancerous Conditions/chemically induced/*prevention & control ; Rats ; Rats, Sprague-Dawley ; Support, Non-U.S. Gov't

Animals ; Apoptosis ; Azoxymethane ; Colorectal Neoplasms ; chemically induced ; metabolism ; pathology ; Cytoskeletal Proteins ; metabolism ; Precancerous Conditions ; chemically induced ; metabolism ; pathology ; Rats ; Rats, Inbred F344 ; Trans-Activators ; metabolism ; beta Catenin

We investigated the expression of the growth-related nuclear proto-oncogenes, c-fos and c-myc, in early preneoplastic regions and tumor nodules of 3'-MeDAB induced rat hepatocarcinoma. To amplify the levels of these transcripts, we gave cycloheximide (100 mg/kg B.W. i.p.) to each group of rats. The elevated levels of the 2.2 kb c-fos and 2.4 kb c-myc transcripts appeared as early as the 2nd week after feeding on the 3'-MeDAB diet and lasted through the 4th; 6th weeks and tumor. Southern blot analysis indicated that gross amplification or rearrangements were not observed in DNA of the preneoplastic livers and hepatoma nodules. We also measured the rate of the incorporation of [3H] thymidine into hepatic DNA in order to monitor the rate of cell proliferation occurring at the early preneoplastic periods. We have found that the rate of [3H] thymidine incorporation corresponds to the elevated levels of c-fos and c-myc transcripts in the precancerous stages. This finding suggests that the elevated expressions of c-fos and c-myc may result from the continuous cell proliferative stimuli generated in the carcinogen altered cells, which is essential to the initiation and promotion of chemical hepatocarcinogenesis.
Animal ; Blotting, Southern ; DNA/biosynthesis ; Female ; *Gene Expression ; *Genes, fos ; *Genes, myc ; Liver Neoplasms, Experimental/chemically induced/*genetics ; Methyldimethylaminoazobenzene/*toxicity ; Precancerous Conditions/chemically induced/*genetics ; Rats ; Rats, Sprague-Dawley ; Support, Non-U.S. Gov't

OBJECTIVETo explore the hepatic injury induced by CCl4in SD rat.

METHOD40 SD rats were allocated to male and female group, consisting of 20 animals/sex/group. SD rats were given at 2 mL x kg(-1) of 10% CCl4 through celiac injection per 3 day for 12 days. All rats were killed by anaesthesia of ethyl ether and bleeding through abdominal aorta at 12th day. Liver tissue was fixed in 10% neutral formalin, embedded in paraffin, cut at a nominal thickness of 3 microm, stained with hematoxylin and eosin ( H&E) , evaluated at by microscopic examination.

RESULT19 cases with local necrosis, 8 cases with fatty degeneration, 9 cases with cystic degeneration and 2 cases with fibrosis were seen in group male. 20 cases with local necrosis, 9 cases with fatty cases degeneration, 1 case with cystic degeneration and 1 case with fibrosis were seen in group female. The incidence of cystic degeneration in male group was found significantly higher than that in female group (P < 0. 05) , but the incidence of other lesions was no significant difference between male and female group.

CONCLUSIONCCl4 induces local necrosis , fatty degeneration, fibrosis and cystic degeneration in SD rat. The incidences of local necrosis , fatty degeneration and fibrosis were no significantly difference between male and female rat, but the incidence of cystic degeneration in male rats was significant higher than that in female rats.

Animals ; Carbon Tetrachloride ; Chemical and Drug Induced Liver Injury ; Cysts ; chemically induced ; pathology ; Disease Models, Animal ; Female ; Liver ; pathology ; Liver Cirrhosis ; chemically induced ; pathology ; Liver Diseases ; pathology ; Liver Neoplasms ; chemically induced ; pathology ; Male ; Precancerous Conditions ; chemically induced ; pathology ; Rats ; Rats, Sprague-Dawley ; Sex Factors

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

OBJECTIVETo examine and analyze the global gene expression at the different stages of golden hamster cheek pouch mucosa carcinomatous change induced by 9,10-dimethylene-1,2 benzanthracene (DMBA).

METHODSThe model of golden hamster cheek pouch squamous cell carcinoma was induced by DMBA. The RNA of normal mucosa, precancerous lesions and squamous cell carcinoma of fresh tissue of golden hamsters was extracted and purified and the cRNA labeled by fluorescent Cy3 synthesized, which respectively hybridized with the agilent rat cDNA microarray containing 41 000 genes-expressed sequence tags, scanning with Agilent G2565AA fluorescence scanner. The Ratio>or=2 and Ratio

RESULTSA total of 5255 differentially expressed genes were detected during the process from normal mucosa to the squamous cell carcinoma, of which 2896 was up-regulated and 2359 down-regulated. There were 22 genes that showed continues abnormal expression through the three different stages of carcinomatous change, including 3 up-regulated, 19 down-regulated. The RT-PCR results of Eaf-2 and Ecg-2 were consistent with the gene chip.

CONCLUSIONSThe development of oral mucosal squamous cell carcinoma involved a number of abnormal genes. The genes showing continues abnormal expression at different stages of carcinomatous change may be the important pathogenetic ones.

9,10-Dimethyl-1,2-benzanthracene ; Animals ; Carcinogens ; Carcinoma, Squamous Cell ; chemically induced ; genetics ; pathology ; Cheek ; Cricetinae ; Female ; Gene Expression Profiling ; Gene Expression Regulation, Enzymologic ; Male ; Mesocricetus ; Mouth Mucosa ; metabolism ; Mouth Neoplasms ; chemically induced ; genetics ; pathology ; Oligonucleotide Array Sequence Analysis ; Precancerous Conditions ; chemically induced ; genetics ; pathology ; RNA, Complementary ; genetics ; Random Allocation ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo evaluate the chemopreventive effects of boswellic acid and curcumin on 7,12-dimethyl benzanthracene(DMBA)-induced oral carcinogenesis in the hamster cheek pouch model.

METHODSMale Syrian golden hamsters (6 - 8 weeks old, 80 - 130 g in weight) were randomly divided into seven groups, with group A serving as the untreated negative control. The left cheek pouch of the remaining hamsters was topically treated with 0.5% DMBA in mineral oil three times a week for 6 weeks. They were then randomized to six groups with group B serving as a positive control and receiving no further treatment. Groups C-G were treated topically with 5, 10 mg/L boswellic acid, 5, 10 µmol/L curcumin, or the combination of 5 mg/L boswellic acid and 5 µmol/L curcumin three times per week for 18 weeks. The animals were injected with bromodeoxyuridine intraperitoneally at 50 mg/kg 2 h prior to killing. At the 25 th week all the hamsters were sacrificed and cheek pouch tissue was harvested. One half of the tissue was snap frozen in liquid nitrogen for analysis of arachidonic acid metabolites, and the other half was fixed in 10% phosphate-buffered saline(PBS)-buffered formalin for histopathological examination.

RESULTSSix-weeks of DMBA followed by 18-weeks of topical application of boswellic acid and curcumin, both boswellic acid (5, 10 mg/L) and curcumin (5, 10 µmol/L) significantly inhibited the incidence from 93.8% to 73.9% (P > 0.05), numbers from 2.19 ± 0.98 to 1.13 ± 0.81 (P < 0.01) and size of visible tumors. Microscopically the incidence of squamous cell carcinoma and BrdU index were also significantly suppressed by boswellic acid and curcumin.

CONCLUSIONSBoth boswellic acid and curcumin were effective in preventing oral carcinogenesis in DMBA-induced hamster cheek pouch model.

9,10-Dimethyl-1,2-benzanthracene ; Animals ; Antineoplastic Agents ; therapeutic use ; Bromodeoxyuridine ; Carcinogenesis ; drug effects ; Carcinogens ; Carcinoma, Squamous Cell ; chemically induced ; pathology ; prevention & control ; Cheek ; pathology ; Cricetinae ; Curcumin ; therapeutic use ; Hyperplasia ; Leukotriene B4 ; metabolism ; Male ; Mesocricetus ; Mouth Neoplasms ; chemically induced ; pathology ; prevention & control ; Precancerous Conditions ; chemically induced ; pathology ; prevention & control ; Random Allocation ; Triterpenes ; therapeutic use

OBJECTIVETo investigate the enhancive effect of N,N'-dinitrosopiperazine (DNP) on induced carcinogenesis in nasal and/or nasopharyngeal epithelia among TgN(p53mt-LMP1)/HT transgenic mice to examine the underlying mechanism for the development of nasopharyngeal carcinoma (NPC).

METHODSTgN(p53mt-LMP1)/HT transgenic mice and the same strain of C(57)BL/6J wild-type mice both at the age of 5 months were randomly divided into 2 groups in parallel, respectively, i.e., TgN(p53mt-LMP1)/HT cancerous lesion-inducing group (TI), TgN(p53mt-LMP1)/HT control group (TC), C57BL/6J cancerous lesion-inducing group (CI), and C57BL/6J control group (CC). TI and CI mice were treated only with DNP for 16 weeks, twice each week, while TC and CC mice were given the same volume of saline as controls. At the end of treatment, animals were sacrificed to collect epithelial tissue samples from nasal cavity and nasopharynx for pathohistological evaluation by haematoxylin and eosin (HE) staining and for determination on the expression of TRAF2, c-Jun, and p16 by immunohistochemistry.

RESULTSAtypical hyperplasia was more significant in the samples of TI than in those of TC, CI, and CC, with the rates of lesions being 90%, 10%, 0, and 0 (P<0.01) respectively, though DNP was used alone in a much shortened inducing period at less dosage and without the use of carcinogenic promoter 12-O-tetradecanoylphorbol-13-acetate as usual. The expressions of tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2) and c-Jun in these samples were significantly up-regulated in TI (P<0.01), while the expression of p16 was significantly lower in TI than in the other groups (P<0.01).

CONCLUSIONTgN(p53mt-LMP1)/HT mice hold inherited constitutional defect in immune surveillance function, which can be aggravated by environmental carcinogens, such as DNP used even though in a much less strength. The enhanced carcinogenesis-inducing effect of DNP on TgN(p53mt-LMP1)/HT mice should be closely associated with abnormal signaling of activator protein-1 (AP-1) pathway, especially up-regulated expressions of TRAF2 and c-Jun, and down-regulated expression of p16.

Animals ; Epithelial Cells ; drug effects ; metabolism ; pathology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Mice ; Mice, Transgenic ; Mutation ; genetics ; Nasopharyngeal Neoplasms ; chemically induced ; genetics ; metabolism ; pathology ; Nitrosamines ; pharmacology ; Nose Neoplasms ; chemically induced ; genetics ; metabolism ; pathology ; Precancerous Conditions ; chemically induced ; genetics ; pathology ; TNF Receptor-Associated Factor 2 ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; Viral Matrix Proteins ; genetics ; metabolism