Biomedical subjects

Ming You

Publications and source records attributed to Ming You.

At least 55 records · Page 3Linked to original sources

PubMed2003

CD24 is a genetic modifier for risk and progression of multiple sclerosis.

Multiple sclerosis (MS) is a chronic neurological disease of unknown etiology, but a genetic basis for the disease is undisputed. We have reported that CD24 is required for the pathogenicity of autoreactive T cells in experimental autoimmune encephalomyelitis, the mouse model of MS. Here we investigate the contribution of CD24 to MS by studying single-nucleotide polymorphism in the ORF among 242 MS patients and 207 population controls. This single-nucleotide polymorphism results in replacement of alanine (CD24a) with valine (CD24v) in the mature protein. We found that the CD24v/v renders a >2-fold increase in the relative risk of MS in the general population (P = 0.023). Among familial MS, the CD24v allele is preferentially transmitted into affected individuals (P = 0.017). Furthermore, 50% of CD24v/v patients with expanded disability status scale 6.0 reached the milestone in 5 years, whereas the CD24a/v (P = 0.00037) and CD24a/a (P = 0.0016) patients did so in 16 and 13 years, respectively. Moreover, our data suggest that the CD24v/v patients expressed higher levels of CD24 on peripheral blood T cells than did the CD24a/a patients. Transfection with CD24a and CD24v cDNA demonstrated that the CD24v allele can be expressed at higher efficiency than the CD24a alleles. Thus, CD24 polymorphism is a genetic modifier for susceptibility and progression of MS in the central Ohio cohort that we studied, perhaps by affecting the efficiency of CD24 expression on the cell surface.

Alanine↗

PubMed2003

Positional cloning of the major quantitative trait locus underlying lung tumor susceptibility in mice.

Pulmonary adenoma susceptibility 1 (Pas1), located on chromosome 6, is the major locus affecting inherited predisposition to lung tumor development in mice. We have fine mapped the Pas1 locus to a region of approximately 0.5 megabases by using congenic strains of mice, constructed by placing the Pas1 region of chromosome 6 from A/J mice onto the genetic background of C57BL/6J mice. Systematic characterization of Pas1 candidates establishes the Las1 (lung adenoma susceptibility 1) and Kras2 (Kirsten rat sarcoma oncogene 2) genes as primary candidates for the Pas1 locus. Clearly, Kras2 affects lung tumor progression only, and Las1 is likely to affect lung tumor multiplicity.

Adenoma↗

PubMed2003

Farnesyltransferase inhibitors are potent lung cancer chemopreventive agents in A/J mice with a dominant-negative p53 and/or heterozygous deletion of Ink4a/Arf.

Mutations in the Kras2 gene are seen in both human and mouse lung adenocarcinomas. The protein product (p21ras) encoded by the Kras2 gene must be post-translationally modified at a terminal CAAX motif in order to be biologically active. In this study, we systematically investigated the chemopreventive efficacy of two different farnesyltransferase inhibitors (FTIs): one is a peptidomimetic (FTI-276) and the other is an imidazole (L778-123). Both FTIs are designed to inhibit the post-translational modification of p21ras proteins with a terminal CAAX motif. In a complete chemoprevention study, where the inhibitor was administered before carcinogen was given, and throughout the study, FTI-276 treatment significantly reduced both the tumor multiplicity by 41.7% (P<0.005), and the total tumor volume by 79.4% (P<0.0001). In the late treatment study, where mice were treated with an inhibitor 12 to 20 weeks after carcinogen administration, FTI-276 treatment resulted in a 60% reduction in tumor multiplicity and 58% reduction in tumor volume. Next, we examined the chemopreventive efficacy of a new FTI, L-778,123, on lung tumor development in A/J mice and transgenic mice with a dominant-negative p53 mutation and/or heterozygous deletion of Ink4a/Arf. Treatment of mice with L-778,123 for a period of 10 weeks from 20 weeks to 30 weeks post carcinogen initiation resulted in an approximately 50% decrease in tumor multiplicity in wild-type mice and mice with a dominant-negative p53 mutation and/or heterozygous deletion of the Ink4a/Arf tumor suppressor genes. Interestingly, tumor volume was decreased approximately 50% in wild-type mice and in mice with an Ink4a/Arf heterozygous deletion, while tumor volume was decreased approximately 75% in animals with a dominant-negative p53 and in mice with both a p53 mutation and heterozygous deletion of Ink4a/Arf. This result suggests that FTI exhibited a significantly (P<0.05) more efficacious chemopreventive effect in animals with alterations of p53 and Ink4a/Arf as contrasted with wild-type mice. Thus, FTIs are potent lung chemopreventive agents in both A/J mice and transgenic mice harboring a dominant-negative p53 and heterozygous deletion of Ink4a/Arf. In fact, L-778,123 is more effective in inhibiting primary lung progression in mice with a p53 mutation and/or an Ink4a/Arf deletion than in wild-type animals.

Adenocarcinoma↗

PubMed2003

A high performance test of differential gene expression for oligonucleotide arrays.

Logit-t employs a logit-transformation for normalization followed by statistical testing at the probe-level. Using four publicly-available datasets, together providing 2,710 known positive incidences of differential expression and 2,913,813 known negative incidences, performance of statistical tests were: Logit-t provided 75% positive-predictive value, compared with 5% for Affymetrix Microarray Suite 5, 6% for dChip perfect match (PM)-only, and 9% for Robust Multi-array Analysis at the p < 0.01 threshold. Logit-t provided 70% sensitivity, Microarray Suite 5 provided 46%, dChip provided 53% and Robust Multi-array Analysis provided 63%.

Algorithms↗

PubMed2003

Mice with alterations in both p53 and Ink4a/Arf display a striking increase in lung tumor multiplicity and progression: differential chemopreventive effect of budesonide in wild-type and mutant A/J mice.

p53 transgenic mice carrying a dominant negative mutation were crossed with Ink4A/Arf heterozygous-deficient mice to investigate whether there is a synergy between these two germ-line mutations in promoting carcinogen-induced lung tumor progression in mice. Mice with a p53 dominant negative mutation and Ink4A/Arf heterozygous deficiency exhibited >20-fold increase in tumor volume compared with approximately 4-fold increase in Ink4A/Arf heterozygous-deficient mice and a 9-fold increase in mice with only the p53 dominant negative mutation. The effect of Ink4A/Arf heterozygous deficiency on lung tumor progression occurred late in the carcinogenesis process (>30 weeks after carcinogen treatment). In addition, most of the lung tumors (approximately 80%) from mice with a p53 mutation and deletion of Ink4A/Arf were lung adenocarcinomas. In contrast, lung adenocarcinomas were seen in <10% of the lung tumors from the wild-type mice and approximately 50% of the lung tumors from Ink4a/Arf heterozygous-deficient or p53 mutant mice. These results indicate a significant synergistic interaction between the presence of a mutant p53 transgene and the Ink4A/Arf deletion during lung tumor progression (P < 0.01). The usefulness of this new mouse model in lung cancer chemoprevention was examined. The chemopreventive efficacy of budesonide was examined in wild-type mice, mice with Ink4A/Arf heterozygous deficiency, mice with a mutation in the p53 gene, or mice with both a mutation in the p53 gene and deletion in the Ink4A/Arf locus. Mice treated with budesonide displayed an average of 90% inhibition of lung tumor progression in a standard 18-week chemoprevention assay, regardless of p53 and/or Ink4A/Arf status. However, the efficacy of budesonide against lung tumor progression decreased from 94 to 77% (P = 0.07) in mice with alterations in both p53 and Ink4A/Arf in a 40-week chemoprevention assay. Similarly, when mice bearing established lung adenomas were treated with budesonide, genotype-dependent differential effects of budesonide in wild-type and mutant mice were clearly revealed with a 82, 64, 45, and 33% decrease in tumor volume in wild-type mice, p53(+/+)Ink4a/Arf(+/-) mice, p53(+/-)Ink4a/Arf(+/+) mice, and p53(+/-)Ink4a/Arf(+/-), respectively. Thus, mutant mice with alterations in p53 and/or Ink4A/Arf exhibited a significant resistance to chemoprevention by budesonide. Because p53 and Ink4a/Arf mutations are the most prevalent mutations in human lung cancers, the effectiveness of chemopreventive agents on the mutant A/J mice containing alterations with p53 and Ink4a/Arf is the best preclinical estimate of their efficacy in humans. Thus, the mutant A/J mouse model should prove useful for chemoprevention studies.

Adenocarcinoma↗

PubMed2003

Fine mapping and identification of candidate pulmonary adenoma susceptibility 1 genes using advanced intercross lines.

In the present study, we used newly developed F(11) generation mouse advanced intercross lines (AIL) to fine map Pas1-3 quantitative trait loci (QTL). The (A/J x C57BL/6) F(11) AIL mouse population was created by crossing lung tumor-resistant C57BL/6 mice with lung tumor-susceptible A/J mice. By selectively genotyping 30% of the population, we have confirmed the Pas1 QTL and narrowed it to an interval of approximately 1.0 cM or 1.3 Mb in the vicinity of the Kras2 gene. The Pas2 QTL was detected by both ANOVA and regression analysis but not by MapMaker EXP/QTL software. In addition, an interaction between the Pas1 and Pas2 QTLs was revealed. However, the Pas3 QTL was not confirmed in this study. It was either lost during the development of the AIL or too weak to be detected using AIL. The Pas1 locus is now sufficiently fine-mapped that candidate gene(s) for the Pas1 locus can be characterized by positional cloning. In this study, all 27 of the known or predicted genes located in the Pas1 candidate region were characterized as possible candidate Pas genes. Six genes were selected for additional analyses because of their relevant function in tumorigenesis or allelic changes between A/J and C57BL/6 mice. The Lrmp gene bears amino acid polymorphisms among various mouse strains that are highly correlated with the Pas1 allele status. The Pas1c1 gene (RIKEN Ak016641), encoding an intermediate filament tail domain-containing protein, produces alternatively spliced transcripts across inbred strains of mice, and its splicing pattern cosegregates with the Pas1 allele. The genetic and expression data support these two genes as strong candidates for the Pas1 locus. Of the other four genes (Eca39, RIKEN Ak015530, mHoj-1, and Krag), no functional polymorphisms or differential gene expression were found in Eca39, mHoj-1, and Krag between lung tumor-susceptible and -resistant strains. The Ak015530 carries an amino acid polymorphism, but this polymorphism does not cosegregate with mouse lung tumor susceptibility. Thus, these 4 genes are less likely candidates for the Pas1 locus.

Adenoma↗

PubMed2003

LOH of chromosome 12p correlates with Kras2 mutation in non-small cell lung cancer.

Previous observation has shown that the wild-type Kras2 allele is a suppressor of lung cancer in mice. Here we report that loss of heterozygosity (LOH) of chromosome 12p was detected in approximately 50% of human lung adenocarcinomas and large cell carcinomas, and Kras2 mutations were detected at codon 12 in approximately 40% of adenocarcinomas and large cell carcinomas. Interestingly, all of the lung adenocarcinomas and large cell carcinomas containing a Kras2 mutation exhibited allelic loss of the wild-type Kras2 allele when a correlation between LOH of the region on chromosome 12p and Kras2 mutation was made. These results from human lung cancer tissues provide a strong evidence in support of our previous observation in mouse models that the wild-type Kras2 is a tumor suppressor of lung cancer.

Adenocarcinoma↗

PubMed2003

Molecular alterations and lung tumors in p53 mutant mice exposed to cigarette smoke.

Mutations and deletions in p53 are the most common genetic lesions in human cancer,and an extraordinarily high incidence of lung cancer occurs in smokers suffering from Li-Fraumeni syndrome, which is characterized by germ-line inactivation of one p53 allele. In contrast, p53 mutations are infrequent in lung tumors formed in A/J mice. Moreover, despite the dominant role of cigarette smoke in the epidemiology of human lung cancer, it is very difficult to reproduce the lung tumorigenicity of this complex mixture in animal models. We used a transgenic mouse with a dominant-negative p53 mutation to examine the effects of a mutant p53 on smoke-induced lung carcinogenesis in mice. p53 mutant (UL53-3 x A/J)F(1) mice of both genders and their wild-type (wt) littermate controls were exposed whole-body to environmental cigarette smoke (ECS) for up to 9.5 months. Untreated mutant mice of both genders underwent an early stimulus of bronchial cell proliferation, and an age-related formation of DNA adducts in lung and heart. In males, there was an age-related increase of micronucleated normochromatic erythrocytes in peripheral blood and an impairment of body weight gain. These findings underscore a physiological protective role of p53 in wt A/J mice. The response of wt and mutant mice to ECS was similar in terms of oxidative DNA damage in lung and heart, proliferation of the bronchial epithelium, and levels of p53 oncoprotein, as assessed after exposure for 28 days. In contrast, ECS-exposed mutant mice underwent a lower induction of apoptosis in bronchial epithelium, a greater formation of DNA adducts in lung and heart, and a more intense cytogenetic damage, shown by a higher frequency of micronuclei in pulmonary alveolar macrophages and in peripheral blood normochromatic erythrocytes. Interestingly, at the end of the experiment, DNA adducts were not repaired in either wt or mutant mice after discontinuing exposure to ECS for 1 week. A weak but significant increase of lung tumor incidence and multiplicity was induced in p53 mutant (UL53-3 x A/J)F(1) mice after exposure to ECS for either 5 months, followed by recovery in air for 4.5 months, or 9.5 continuative months. Conversely, no tumorigenic effect was observed in their wt littermate controls, carrying a 99.9% A/J background and 5% FVB genome. This contrasts with the weakly positive results obtained in previous studies using wt A/J mice. Thus, in agreement with the results of previous lung tumorigenicity studies performed with the smoke carcinogens benzo(a)pyrene and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone, (UL53-3 x A/J)F(1) mice carrying a mutant p53 transgene appear to be more sensitive to ECS than the corresponding wt littermate controls. These findings provide evidence that p53 mutations play a role in smoke-related carcinogenesis not only in humans but also in A/J mice.

Animals↗

PubMed2003

Differentially expressed nucleolar TGF-beta1 target (DENTT) in mouse development.

Differentially expressed nucleolar TGF-beta1 target (DENTT) is a recently identified gene whose mRNA is differentially affected by TGF-beta1 in TGF-beta1-responsive human lung cancer cells and who is a new member of the TSPY/TSPY-like/SET/NAP-1 (TTSN) protein superfamily. Here, we report that mouse DENTT mRNA contains a 2031-bp open reading frame that encodes a predicted polypeptide of 677-amino acids with a relative molecular mass of 77,671 Da. The mouse and human DENTT sequences show 77% and 78% homology at the nucleotide and amino acid level, respectively. Mouse DENTT is predicted to be a nuclear protein with two nuclear localization signals (NLS), two coiled-coil regions, and a domain that shows significant identity to a region that defines the TTSN superfamily. Green fluorescent protein (GFP)-tagged full-length mouse DENTT transfected into COS-7 cells showed localization predominantly in the nucleolus. Reverse transcription-polymerase chain reaction amplification, Northern hybridization, and Western blot analyses showed expression of mouse DENTT mRNA and protein throughout mouse embryogenesis. Immunohistochemical staining analysis showed that DENTT is expressed in multiple tissues in a defined spatiotemporal pattern during mouse embryogenesis. The heart and primitive brain were the first organs of the embryo that showed immunoreactivity for the DENTT antibody by day 8 of development (E8). In the developing mouse brain, the choroid plexus was intensely stained for DENTT in all stages of development. The spinal cord and dorsal root ganglia were also positive for DENTT staining beginning in the 11-day-old embryo (E11), where homogeneous immunostaining was observed throughout the developing neurons. By day 16 of development (E16), only a small subset of the neuronal population in the spinal cord and dorsal root ganglia was positively stained for DENTT. DENTT immunoreactivity increased steadily with maturation as the differentiation of cartilage and osteoblasts proceeded and reached a maximum in the growth plate during endochondral ossification. DENTT expression was also detected in multiple rodent cell types in vitro, including mouse F9 embryonal carcinoma (EC) cells. Addition of retinoic acid or sodium butyrate to F9 EC cells showed a rapid decrease in expression of DENTT protein occurring by 1 hr that continued to decrease to almost undetectable levels after 24 hr. Cotransfection of full-length mouse DENTT expression plasmid with 3TPLux or COL7A1Luc Luciferase reporter plasmids into F9 EC cells significantly increased the level of 3TPLux reporter transcription while decreasing the level of COL7A1Luc reporter transcription, suggesting that DENTT may play multiple roles in modulating transcriptional responses. These findings suggest new roles for the TTSN superfamily during embryogenesis and differentiation.

3T3 Cells↗

PubMed2003

Tnfa and Il-10 deficiencies have contrasting effects on lung tumor susceptibility: gender-dependent modulation of IL-10 haploinsufficiency.

Epidemiologic evidence suggests that pulmonary diseases with a prominent chronic inflammatory component elevate lung cancer risk. Genetic manipulations of mouse models of lung inflammation and tumorigenesis can be used to investigate this association. The genes encoding pro-inflammatory tumor necrosis factor-alpha (TNFalpha) and antiinflammatory IL-10 cytokines map within quantitative trait loci that regulate susceptibility to lung tumor development in mice; sensitive A/J and resistant C57BL/6J (B6) mice have different Tnfa and Il-10 alleles. Genetic ablation studies were performed to examine whether these genes would qualify as candidate tumor modifiers. Tnfa null (-/-) mice on a B6 background and B6.129 Il-10(-/-) mice were intercrossed with A/J mice and subjected to urethane carcinogenesis; lung tumor multiplicity was determined 20 weeks later. In the absence of one copy of Tnfa, tumor number. Male Il-10(+/+) mice developed more tumors than did female mice (P < 0.001), absence of one copy of Il-10 raised tumor number in female mice to that observed in +/+ males, but no change in multiplicity occurred in Il-10 hemizygous males. Thus, a deficit of pro-inflammatory TNFalpha decreased the number of tumors, whereas diminished gene copy number of anti-inflammatory IL-10 increased tumorigenesis; manifestation of an effect of Il-10 haploinsufficiency is gender dependent. These studies support a role for inflammation in lung cancer susceptibility.

Alleles↗

PubMed2003

Cell proliferation, apoptosis, and expression of cyclin D1 and cyclin E as potential biomarkers in tamoxifen-treated mammary tumors.

Tamoxifen has been widely used for treatment, and more recently, for the prevention of breast cancer. Since breast carcinomas are composed of heterogeneous populations of estrogen receptor-positive (ER+) cells, we hypothesized that tamoxifen may suppress tumor growth by differentially affecting cell proliferation and apoptosis. ER+ mammary tumors were induced in Sprague-Dawley rats by N-methyl-N-nitrosourea (MNU) and when they became palpable, the animals were treated for 5, 10, or 20 days with tamoxifen, 1.0 mg/kg body weight. Tamoxifen induced a time-dependent decrease in proliferating (BrdU-labeled) cells, arrested the cells in G1/0 phase, and differentially decreased the cyclin E and cyclin D1 expression at mRNA and protein levels. In the same tumors, apoptotic cells increased during the first 10 days of treatment, but their number remained unchanged with extension of the treatment to 20 days. Thus, we provide data that tamoxifen may differentially affect cell proliferation and apoptosis in mammary tumors and that the expression levels of cyclin D1 and cyclin E might also be considered potential intermediate biomarkers of response of mammary tumors to tamoxifen and possibly to other selective estrogen receptor modulators (SERMs).

Animals↗

PubMed2002

Carcinogenic induction directs the selection of allelic losses in mouse lung tumorigenesis.

Recent evidence suggests that genome-wide allelic imbalances are inducible by carcinogens and may occur as cells adapt to carcinogenic exposure during tumorigenesis. We investigated the role of carcinogenic exposure on global and selected loss of heterozygosity (LOH) during mouse lung adenocarcinogenesis. Tumor induction by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) or vinyl carbamate (VC) resulted in a significant overall increase in the number of chromosomes affected by LOH per tumor when compared with spontaneous lung tumors. Allelic loss on chromosome 12 occurred at a frequency of 35% and 40% in NNK- and VC-induced tumors, respectively, compared with 8.3% in spontaneous tumors (P < 0.01). In contrast, spontaneous lung adenocarcinomas displayed LOH on chromosome 4 at a frequency of 77%, whereas a frequency of only 36% (P < 0.001) was observed in tumors induced by NNK. Sixty-four percent of the VC-induced tumors displayed LOH on chromosome 4. In addition, allelic losses on chromosomes 12 and 14 were significantly associated with an increase in chromosomal instability, suggesting that genes inactivated on these chromosomes may contribute to this effect. The results from this study demonstrate that genotoxic carcinogens increase chromosome instability, as evidenced by a significant increase in global LOH frequency, and significantly alter the selection of chromosomal alterations during lung tumor development.

Adenocarcinoma↗

PubMed2002

Linkage disequilibrium mapping of novel lung tumor susceptibility quantitative trait loci in mice.

Linkage disequilibrium (LD) has been used to map chromosomal regions regulating quantitative traits, also called quantitative trait loci (QTLs). With the increasing number of available mouse polymorphic genetic markers, LD can be estimated for the purpose of fine-mapping a given QTL or in the identification of novel QTLs. A whole-genome LD analysis was conducted for mapping mouse lung tumor susceptibility QTLs in 25 strains of mice with known susceptibility to lung cancer using 5638 genetic markers. A total of 63 markers were found to be significantly associated with lung tumor susceptibility, many of which were novel QTLs. This study demonstrates the feasibility of using LD to map QTLs on a whole genome level. Further characterization of the newly identified lung tumor susceptibility QTLs may lead to the identification of genes whose human homologue may predispose some individuals to lung cancer.

Animals↗

PubMed2002

A strong candidate gene for the Papg1 locus on mouse chromosome 4 affecting lung tumor progression.

Lung cancer is the leading cause of cancer death among both men and women, accounting for more than 28% of all cancer deaths. In fact, more people die of lung cancer than of colon, breast, and prostate cancers combined. Although lung cancer is largely induced by smoking, there is strong evidence for genetic susceptibility and gene-environment interactions in the development of lung cancer. Inbred mouse models offer an effective means of identifying candidate lung cancer susceptibility loci since genetic heterogeneity and enormous variation in exposure levels to environmental agents make it difficult to identify lung cancer susceptibility loci in humans. Papg-1 (pulmonary adenoma progression 1) was previously mapped to a region on mouse chromosome 4. This locus contains a candidate gene, Cdkn2a also referred to as Ink4a/Arf, which dually encodes two established tumor suppressors p16(INK4a) and ARF. Cdkn2a became a primary candidate for Papg-1 for two reasons: (1) two haplotypes of mouse Cdkn2a were found to segregate with differential genetic susceptibility to lung tumor progression in mice; and (2) in vitro studies showed that the p16(INK4a) allele from the BALB/cJ mouse had a significantly decreased ability to bind and inhibit CDK6 and to suppress cell growth when compared with the p16(INK4a) allele from the A/J mouse. Here, we report that mice with a heterozygous deficiency for the A/J Cdkn2a allele were significantly more susceptible to lung tumor progression than mice with a heterozygous deficiency for a BALB/cJ Cdkn2a allele, when compared to their respective wild type mice. These results offer strong evidence that naturally occurring variation of p16(INK4a) influences susceptibility to enhance lung tumor progression making it a strong candidate for the lung tumor progression locus, Papg-1.

Adenocarcinoma↗

PubMed2002

Differentially expressed genes associated with mouse lung tumor progression.

To detect altered gene expression associated with mouse lung tumor progression, we compared the gene expression profile of lung adenocarcinomas with that of lung adenomas and normal lungs. Autoradiographic analysis showed that among the 588 genes surveyed, 152 genes were detected and the remaining 436 genes did not give any signals. A gene-specific semiquantitative reverse transcription polymerase chain reaction method was used to confirm the expression profile. A total of 29 genes was found to be differentially expressed in mouse lung tumors when compared to normal lungs. The pattern of expression, either underexpression or overexpression, was the same for 10 genes between adenocarcinomas and adenomas. Among them, seven genes were overexpressed, two genes were underexpressed and one gene was lost. Interestingly, 19 genes showed differential expression or increased incidence or difference in level of change between lung adenomas and adenocarcinomas, including Stat1, ADAP, IGFBP-6, PDGF-A, TGF-beta2, Int-3, VEGFR2, BAX, BAG-1, c-Jun, FasL, TRAIL, YB-1, CD31, Cdc42, B-raf, Rab-2, Abi-1, and ACE. These genes can be designated as candidate 'lung tumor progression' (LTP) genes because their expression changes may specifically affect lung tumor progression in mice. Further analyses of these candidate LTP genes may provide new leads for elucidation of lung tumor progression in mice.

Adenocarcinoma↗

PubMed2002

p53 transgenic mice are highly susceptible to 1, 2-dimethylhydrazine-induced uterine sarcomas.

p53 Transgenic mice were crossed with C57BL/6J mice to investigate whether a germ-line mutation in the p53 gene predisposes for tumorigenesis in mice. (C57BL/6J x UL53-3) F(1) mice were treated with 1,2-dimethylhydrazine (DMH), a colon carcinogen. The presence of a mutant p53 led to an increased incidence or multiplicity of uterine sarcomas, colon carcinomas, lung adenomas, and hepatomas in DMH-treated mice. The most significant effect of mutant p53 was the increased incidence of uterine sarcomas, which were found in approximately 90% of p53(val135/wt) mice but only seen in approximately 10% of p53(wt/wt) mice. After examination of 15 known p53 downstream target genes in uterine sarcomas and normal uteri, we found that expression of the Reprimo gene was significantly increased in normal uteri of p53(wt/wt) mice but not in either normal uterus or uterine sarcomas of p53(val135/wt) mice. In DMH-treated animals, long-term treatment with this chemopreventive agent, piroxicam, reduced colon carcinoma incidence and multiplicity in both p53(val135/wt) or p53(wt/wt) mice but did not affect the formation of uterine sarcomas, lung adenomas, or hepatomas. These results demonstrate a tissue-specific enhancement of tumorigenesis in multiple organs by the mutant p53 transgene and additionally support the utility of (C57BL/6J x UL53-3) F(1) mice for chemoprevention studies.

1,2-Dimethylhydrazine↗

PubMed2002

Detection of genomic alterations in human endometrial cancer by two-dimensional gel electrophoresis.

OBJECTIVE: The purpose of this study was to detect genomic alterations in human endometrial cancer by two-dimensional gel electrophoresis. STUDY DESIGN: With use of a newly developed two-dimensional gel electrophoresis assay, we scanned 19 high-risk DNA fragments for alterations in human endometrial hyperplasias and adenocarcinomas. This method includes cleaving of high-molecular-weight DNA, radioactive labeling, and separating DNA fragments by two-dimensional gel electrophoresis. By comparing the two-dimensional gel electrophoresis profile (spots) of neoplastic with normal endometrium, genetic alterations such as amplification, allelic loss, and hypermethylation or hypomethylation can be detected. RESULTS: Seven of 8 human endometrial adenocarcinoma (88%) and 1 of 2 hyperplasias (50%) revealed changes in spot density. The number of spots changed per specimen was 4. The median percentage of specimens with changes in an individual spot was 30%. Eleven spots had a reduction or loss of spot density, and 8 spots had an increase in spot density. CONCLUSION: By use of a novel two-dimensional gel electrophoresis assay, we identified genetic alterations in 50% of hyperplasias and 88% of endometrial adenocarcinomas.

Adenocarcinoma↗

PubMed2002

Differential gene expression in human lung adenocarcinomas and squamous cell carcinomas.

PURPOSE: Differential cDNA library screening was performed on 7 human lung adenocarcinomas and 7 human lung squamous cell carcinomas and their corresponding adjacent normal tissues using a human lung cDNA library constructed from the normal bronchoalveolar cells of a 72-year-old male smoker. EXPERIMENTAL DESIGN: Of the 2758 clones that were differentially expressed between normal and tumor tissues in the preliminary cDNA library screening analysis, 1163 clones were confirmed by dot blot, revealing a confirmation rate of >40%. DNA of confirmed clones was sequenced and was subjected to GenBank Blast searches. RNA expression levels were then individually analyzed by semiquantitative reverse transcription-PCR. RESULTS: Ninety-two genes/sequences were differentially expressed in adenocarcinomas and/or squamous cell carcinomas compared with their corresponding normal tissues. Several genes were underexpressed by at least 50% in both tumor types such as c-fos, decorin, alpha-2-macroglobulin, platelet endothelial cell adhesion molecule 1, EGR1, and fibronectin. Ribosomal protein S3 was underexpressed only in squamous cell carcinomas, whereas expression of hepatocyte growth factor activator inhibitor type 2, ubiquitin-conjugating enzyme UBC9, and clone 333E23 on chromosome Xq21.1 were altered only in adenocarcinomas. Several genes discovered recently of which the functions are unknown, such as KIAA0728 and KIAA0425, were also differentially expressed in both adenocarcinomas and squamous cell carcinomas of the lung. CONCLUSIONS: Many of these known and novel genes may be involved in human lung tumorigenesis; therefore, additional characterization is warranted and will be beneficial to the understanding of this deadly disease.

Adenocarcinoma↗