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1.
Treatment with estradiol-17ß and testosterone inducesepithelial dysplasia and, subsequently, adenocarcinoma in thedorsolateral prostate of NBL rats. The purpose of this studywas to determine whether this carcinogenic effect is mediatedby genotoxicity. Analogous to adducts produced by estrogensin the male hamster kidney, a target of estrogen carcinogenicity,induction of DNA adducts detectable by 32P-postlabeling wasinvestigated in the prostate target tissue. NBL rats were treatedwith separate Silastic tubing implants containing testosteroneand estradiol-17ß. Control animals received emptyimplants. Animals were killed at 8, 16 and 24 weeks after initiationof treatment, and accessory sex glands were sampled for adductanalysis. DNA of the dorsolateral and ventral prostate and thecoagulating gland (= anterior prostate) was isolated and analyzedby nuclease Pl-enhancement of the 32P-postlabeling assay. DNAadducts were quantitated by Cerenkov counting. An adduct occurredselectively in DNA of the dorsolateral prostate of rats treatedwith estradiol plus testosterone for 16 or 24 weeks with relativeadduct level values of 相似文献
2.
Biochemical alterations in sex hormone-induced hyperplasia and dysplasia of the dorsolateral prostates of Noble rats 总被引:13,自引:0,他引:13
I Leav S M Ho P Ofner F B Merk P W Kwan D Damassa 《Journal of the National Cancer Institute》1988,80(13):1045-1053
Simultaneous implantation of intact Noble (Nb) rats with testosterone and 17 beta-estradiol (E2)-filled silastic capsules for 16 weeks caused atypical hyperplasia (dysplasia) and striking enlargement exclusively in the dorsolateral prostates (DLPs) of all animals. The dysplastic lesion may be preneoplastic since long-term administration of these steroids to Nb rats is known to induce a high incidence of adenocarcinoma in the DLP. Treatment of rats with nonaromatizable 5 alpha-dihydrotestosterone (DHT) for 16 weeks caused enlargement but not dysplasia, implicating estrogen as a key factor in the genesis of the proliferative lesion. Compared with controls, the testosterone plus E2 treatment caused a 2.5-fold increase in nuclear type II estrogen binding sites which were confined to the DLP. Neither treatment significantly altered androgen content or levels of androgen receptor in the ventral prostate or DLP. Organ cultures of enlarged DLP containing foci of dysplasia metabolized more [3H]DHT than control tissue, which resulted in increased formation of the 5 alpha-androstane-3 beta, 17 beta-diol (3 beta-androstanediol) metabolite by these explants. Because 3 beta-androstanediol has previously been shown to displace [3H]E2 from cytosolic type I estrogen binding sites, the dysplasia may be caused by hyperstimulation of the DLP by the hormones and their normal metabolites produced in abnormal amounts. 相似文献
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Kenji Niwa Midori Hashimoto Zenglin Lian Jingchun Gao Keiko Tagami Yasuhiro Yokoyama Hideki Mori Teruhiko Tamaya 《Japanese journal of cancer research》2002,93(6):626-635
Short- and long-term experiments were designed to determine the effects of toremifene (TOR) on estrogen-related endometrial carcinogenesis in mice. In the short-term experiment, a single low dose of TOR (0.2 mg / 30 g body weight) decreased expression of c-fos, interleukin (IL)-1alpha, estrogen receptor (ER)-alpha mRNAs and corresponding proteins induced by estradiol-17beta (E(2)), in the uteri of the ovariectomized mice. Expression of ER-beta mRNA was increased by the TOR treatment, compared with the control. In the long-term experiment, 106 female ICR mice were given N-methyl-N-nitrosourea (MNU) into their uterine corpora. The animals were divided into four groups as follows: group 1, E(2) diet (5 ppm) plus TOR (0.2 mg / 30 g body weight, subcutaneously, every four weeks); group 2, E(2) diet alone; group 3, basal diet plus TOR. Group 4 served as the control. TOR treatment decreased the incidence of MNU and E(2)-induced endometrial adenocarcinoma and atypical hyperplasia at the termination of the experiment (30 weeks after the start). These results suggest that TOR exerts preventive effects against estrogen-related endometrial carcinogenesis in mice, through the suppression of c-fos as well as IL-1alpha expression induced by E(2). Such suppressive effects of TOR may be related to the decreased ER-alpha and increased ER-beta expressions. 相似文献
5.
Induction of high incidence of mammary tumour in female Noble rats with a combination of 17beta-oestradiol and testosterone. 总被引:1,自引:0,他引:1
Breast cancer is the most common cancer and the second most frequent cause of cancer death in women. Despite extensive research, the precise mechanisms of breast carcinogenesis remain unclear. One of the reasons for this is due, at least in part, to a lack of a suitable animal model which can closely mimic the breast carcinogenesis in normal situations without using chemical carcinogens. We have developed an animal model of mammary gland carcinogenesis using a combination of oestradiol and testosterone, and succeeded in inducing a high percentage of female Noble rats to develop mammary cancer in a relatively short time (approximately 6 months). The results showed that androgens might work as a promoter to shorten the latency time of mammary gland carcinogenesis. Histopathological examination revealed that hyperplasia and dysplasia were first observed 2 months after treatment, in situ carcinoma after 3 months, and fully developed carcinoma of various forms including cribriform, papillary and camedo types were observed from 5 to 6 months after hormone implantation. Animals implanted with oestrogen or testosterone alone also developed mammary cancers, though with a lower overall incidence than the two hormones combined. They ranged from well differentiated to poorly differentiated forms with predominantly infiltrating ductal carcinoma. We have also observed a case of secondary cancer in the uterus. In addition to the high incidence of carcinoma, there was also a peculiar unexplained ipsilateral correlation between the site of hormonal implantation and the location of tumours, and the highest incidence of carcinogenesis was found to be in thoracic mammary gland. The study showed that both oestrogens and androgens are important in mammary cancer development. The animal model would prove to be a useful model for analysis of the mechanism(s) of hormonal carcinogenesis. 相似文献
6.
This study determined the incidence of prostate adenocarcinomafollowing long-term treatment of NBL and Sprague-Dawley ratswith estradiol-17ß or diethylstilbestrol (DES) plustestosterone and it defined the origin of these tumors. NBLand Sprague-Dawley rats were treated with two Silastic tubingimplants (i.d. 1.6 mm, o.d. 3.2 mm) containing a 2 cm long fillingof testosterone and one implant containing a 1 cm long fillingof estradiol-17ß or DES. Control animals receivedempty implants. Treated animals were killed when moribund andcontrols were killed at 91 (NBL) or 75 (Sprague-Dawley) weeksafter initiation of treatment and accessory sex glands weresampled for histopathological examination of multiple step sections.Prostatic adenocarcinoma occurred in 100% of NBL rats aftertreatment with estradiol-17ß or DES plus testosteronefor 44 and 59 weeks (group means) respectively. Adenocarcinomaincidences were lower in Sprague-Dawley rats. The adenocarcinomaswere small, microscopic, invasive tumors and they were spatiallyclosely associated with the periurethral ducts of the dorsal,lateral and/or anterior (= coagulating gland) prostate, butnever with the ducts of the ventral lobe and seminal vesicles.One adenocarcinoma was of uncertain origin. Duct-acinar dysplasticlesions occurred in the periphery of the dorsal and lateralprostate of all hormone-treated NBL and many Sprague-Dawleyrats, but did not appear to give rise to carcinoma. Althoughsome adenocarcinomas were contiguous with dysplastic ducts ofthe peripheral dorsolateral prostate, the main mass of theseneoplasms was located in the periurethral area. Also, most adenocarcinomaswere only connected with the periurethral ducts, in which atypicalhyperplasia occurred following hormone treatment for 36 weeksor longer. Thus atypical hyperplasia of the periurethral prostateducts, but not peripheral duct-acinar dysplasia, appeared tobe the likely precursor of the induced carcinomas. Testosteroneplus DES, but not estradiol-17ß), induced marked dysplasia-likelesions in the acini of the ventral prostate of all NBL andmany Sprague-Dawley rats. These lesions had progressed to carcinomain situ (or adenoma) in 46% of NBL rats. 相似文献
7.
Epidemiological data reveal that the incidence of liver cancer is markedly higher in men than women. To clarify the mechanism responsible for the induction of higher incidence of liver tumors in male animals, we investigated the modifying effect of sex hormones in diethylnitrosamine (DEN)-induced rat hepatocarcinogenesis. F344 male rats (n=120) were divided into two experiments, experiment I (Exp I) and experiment II (Exp II). In each experiment, 60 rats were randomly allocated into four groups. The mini-osmotic pumps containing doses of 47.5 mg (Exp I) or 23.75 mg (Exp II) of DEN were inserted into the abdominal cavity of each animal to initiate liver carcinogenesis. Animals in group 2 were castrated one week prior to DEN treatment, and animals in groups 3 and 4 were treated with 1 or 10 microg of estradiol-3-benzoate (EB), respectively, one week prior to DEN treatment. Animals in group 1 were treated with DEN alone and sham-operated at the same time. All animals were sacrificed 26 weeks after DEN treatment. In Exp I, liver tumor incidence of group 3 decreased significantly compared with that of group 1 (p<0.05), and tumor multiplicities of groups 2, 3 and 4 were decreased significantly compared to that of group 1 (p<0.01). In Exp II, tumor incidence of group 3 was significantly different (p<0.05) when compared to that of group 1. Immunohistochemical expression of ERalpha was shown in normal appearing cells, but not in tumor cells. Western blot analysis confirmed that ERalpha expression was higher in normal liver tissue compared to tumor tissues. Taken together, we conclude that castration or EB treatment has an inhibitory effect in DEN-induced hepatocarcinogenesis in F344 rats. The reason for ERalpha loss in tumor cells should be further elucidated. 相似文献
8.
Adenocarcinomas of the prostate induced by N-nitroso-N-methylurea in rats pretreated with cyproterone acetate and testosterone 总被引:4,自引:0,他引:4
Prostatic adenocarcinomas were induced in 5 out of 20 Wistar rats upon a single administration of 50 mg/kg N-nitroso-N-methylurea (NMU). The rats were pretreated with a daily dose of 50 mg/kg cyproterone acetate for 3 weeks followed by 3 daily injections of 100 mg/kg testosterone. All tumours developed in the dorsolateral prostate and were invasively growing. In 2 cases distant metastases were found. Three proliferative lesions classified as carcinomas in situ were also found in the dorsolateral prostate. A total of 7/20 animals (35%) carried an adenocarcinoma and/or a carcinoma in situ. In addition, 6 epithelial hyperplasias were observed in the dorsolateral and 1 in the ventral prostate of non-tumour-bearing rats. The method described may provide a good animal model for cancer of the prostate and lead to a better understanding of prostatic carcinogenesis. 相似文献
9.
Production of autochthonous prostate cancer in Lobund-Wistar rats by treatments with N-nitroso-N-methylurea and testosterone 总被引:4,自引:0,他引:4
More than 50% of Lobund-Wistar (L-W) strain rats developed large, palpable prostate adenocarcinomas (PAs) following treatments with N-nitroso-N-methylurea (CAS: 684-93-5) and testosterone propionate [(TP) CAS: 57-85-2], and most of the tumor-bearing rats manifested metastatic lesions. The incubation periods averaged 10.6 months. Within the same timeframe, no L-W rat developed a similar palpable PA when treated only with TP. In L-W rats, TP acted as a tumor enhancement agent, with primary emphasis on the development of prostate cancer. 相似文献
10.
M Finkelstein A Geier H Horn I S Levij P Ever-Hadani 《International journal of cancer. Journal international du cancer》1975,15(1):78-90
Effects of testosterone (T) and estradiol-17beta (E-2) on the synthesis of DNA, RNA and protein were studied in explants of the following types of malignant and non-malignant human female breast grown in organ culture: cystic mastitis (7 cases), fibroadenoma (8), carcinoma (17) and uninvolved tissue from cancer-bearing breast (8). In cultures of systic mastitis T uniformly inhibited the incorporation of thymidine-3H into DNA, uridine-3H into RNA and L-amino acids-14C (AA-14C) into protein. E-2 inhibited the incorporation of thymidine-3H, but had a variable effect on the incorporation of uridine-3H and AA-14C. Cultures of fibroadenoma, with no steroid added, were highly proliferative especially at the outer surface, but the incorporation of thymidine-3H, uridine-3H and AA-14C was much lower than in cystic mastitis. Whereas in fibroadenoma T uniformly inhibited the synthesis of DNA, RNA and protein, the effect of E-2 was variable: in most cases it inhibited the synthesis of DNA,but in one it stimulated it appreciably; in the majority of cases E-2 stimulated RNA and protein synthesis. In cultures of cancerous tissue T depressed, in most cases, the incorporation of thymidine-3H, uridine-3H and AA-14C, but it stimulated it in 4 out of 17. E-2 inhibited the synthesis of DNA, RNA and protein in 6 cases (2 of them were inhibited by T), stimulated them in 9 (one stimulated by T) and had no clear effect in 2. The effect of the steroids on the explants of uninvolved tissue was variable and did not always parallel their effect on the cancerous tissue from the respective patients. 相似文献
11.
Influence of selenium on induced carcinogenesis of the prostate and other organs was studied in male Wistar rats. Carcinogenesis was induced (68) by using our modification of a combined double-stage model including surgical castration, single administration of N-methyl-N-nitrosourea (MNU) and long-term promotion by a mix of testosterone ethers (MTE). Seven days after MNU injection the rats were randomized to form 2 groups. Controls were fed drinking water while the study group - water containing sodium selenite 4mg/l, daily - till the end of the experiment. Controls (12) were not exposed to any treatment. They were followed up for 55 weeks until sacrificed. Apparent benign prostatic hyperplasia developed in rats subjected to castration, MNU and MTE. Also, such precancerous lesions as prostatic intraepithelial neoplasia (PIN) and prostate cancer including metastatic one were detected. Malignant lymphoma, other than in target tissues, was the most frequent. Prostate pathological changes and lymphomas were not registered in intact rats. Unlike rats treated with MNU and MTE and fed untreated drinking water, selenium did not influence significantly the development of prostate intraepithelial neoplasia but reduced multiplicity of prostate cancer by 44.6%. Simultaneously, the incidence of induced malignant lymphomas decreased by 26.4%. 相似文献
12.
Carcinomas of the rat prostate induced by a single injection of N-methyl-N-nitrosourea, 7,12-dimethylbenz(a)anthracene, and 3,2'-dimethyl-4-aminobiphenyl, after sequential treatment with cyproterone acetate and testosterone propionate, were evaluated as potential animal models for prostatic cancer. All ten carcinomas examined were located in the dorsolateral prostate region and did not involve the distal parts of the seminal vesicles and coagulating glands. The incidence of urinary obstruction leading to the animals' death was 6 of 10 rats, and metastases in the lung, abdominal lymph nodes, and/or liver also occurred in 6 of 10 rats. The tumors were invasive adenocarcinomas, showing frequent perineural invasion and a variable degree of differentiation. There were ultrastructural similarities with human prostatic carcinomas, such as intracellular lumina. Plasma acid phosphatase was increased. Enzyme histochemical analysis revealed similarities with the Dunning R3327H and -HI prostatic carcinomas but was not helpful in determining the site of origin of the tumors. The gross and microscopic appearance of the tumors and the observation of preneoplastic lesions exclusively located in the dorsolateral prostate suggest this lobe as site of origin of the carcinomas. Preneoplastic lesions (n = 9) included atypical hyperplasias (n = 5) and lesions with all histological characteristics of carcinoma except for local invasion and metastases, which were classified as carcinoma in situ (n = 4). Although androgen sensitivity could not be assessed, the observed characteristics of the tumors [their long latency time (46-80 weeks), the presence of preneoplastic lesions, and the short duration of the treatment, leaving the animals intact] all indicate that the present approach is a valid animal model for the study of prostatic carcinogenesis. 相似文献
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The influence of synthetic estrogens on the N-nitrosomorpholine (NNM)-induced liver carcinogenesis in ovariectomized young adult female rats was investigated and compared to rats which received only the carcinogen or estrogens. Estrogens when chronically administered after the cessation of carcinogen treatment increased the carcinogenic effect of NNM. In such conditioned animals the number of nodules per number of rats was 23/31, that of hepato-cellular carcinomas 9/31, whereas in animals which received only the hepato-carcinogen the incidence of nodules and carcinomas in liver was respectively 11/31 and 3/31. Higher incidence of benign and malignant tumors in other organs was also observed in these animals. Rats which received a single dose of estrogens simultaneously with NNM developed slightly fewer tumors in liver and in other organs. Since under my experimental conditions the long-term treatment with synthetic estrogens alone did not induce any focus, nodule or hepatocellular carcinoma in the liver. I suggest that the estrogens were acting rather as tumor promotors than true initiators of liver carcinogenesis. 相似文献
15.
We hypothesize that the endogenously present lipoidal estrogen fatty acid esters may have a stronger mitogenic action in the fat-rich mammary tissues than in the uterus. To test this hypothesis, we compared the activity of estradiol-17beta-stearate (E(2)-17beta-S) with that of estradiol-17beta (E(2)) in stimulating the growth of mammary glandular cells versus the growth of uterine endometrial cells in ovariectomized female Sprague Dawley rats. Experimentally, an estimated 0.5 or 5 nmol of E(2)-17beta-S or E(2) was released daily to ovariectomized female rats through an Alzet pump implanted under the back skin of the animal for 10 or 23 days. The growth-stimulatory effect of E(2)-17beta-S and E(2) on mammary glandular cells was determined according to 5-bromo-2'-deoxyuridine labeling indices, and their effect on the uterus was determined by measuring both the 5-bromo-2'-deoxyuridine labeling index and the uterine wet weight. Our results showed that chronic treatment of ovariectomized female rats with 0.5 or 5 nmol/day E(2)-17beta-S for 10 or 23 days had a stronger stimulatory effect on mammary glandular cell proliferation than treatment with equimolar doses of E(2). In the uterus, however, E(2) was more active in stimulating the proliferation of uterine endometrial cells than E(2)-17beta-S at equimolar doses. Our results demonstrated, for the first time, that a naturally occurring estradiol-17beta-fatty acid ester has a differential, strong mitogenic effect in the fat-rich mammary tissues, and this effect was not observed with E(2). It is tempting to suggest that the fatty acid esters of the endogenous estrogens and their bioactive metabolites (e.g., 4-hydroxyestradiol and 16alpha-hydroxyestrone) may be of unique importance for stimulating cell growth and possibly also for inducing tumor formation in the fat-rich mammary tissues as compared with the uterus. More studies are warranted to test these ideas. 相似文献
16.
Promotional effects of testosterone and high fat diet on the development of autochthonous prostate cancer in rats 总被引:4,自引:0,他引:4
Depots of testosterone implanted in Lobund-Wistar (L-W) rats, resulted in increased incidence of prostate adenocarcinomas (PAs) in the dorsal lateral lobe area. In testosterone-treated rats which had been fed the same diet plus 15% corn oil, the prostate tumors were more numerous and they appeared earlier. Rats consuming the same feed containing 15% corn oil (no testosterone) did not produce prostate tumors. Positive correlations were demonstrated between the development of PAs in L-W rats that were treated with testosterone and high fat diet. 相似文献
17.
Serum testosterone (T) and dihydrotestosterone (DHT) were measured by a sensitive and reliable radioimmunoassay in 42 normal subjects and 33 age-matched patients with carcinoma of the prostate. The mean +/- s.e. for serum testosterone in normal subjects was 16.74 +/- 0.76nM and the corresponding value for patients with carcinoma was 20.94 +/- 1.48nM. Statistical analysis of the results showed a significant increase in T level in patients with carcinoma of the prostate (P less than 0.01). In contrast, there was no difference in DHT concentration between the two groups, values being 2.43 +/- 0.09 and 2.06 +/- 0.09nM for normal subjects and patients respectively. The means +/- s.e. for T/DHT ratio in controls and patients were 6.8 +/- 0.2 and 12.8 +/- 1.3 respectively. The difference was highly significant (P less than 0.001). The wide range of variation for T in patients with carcinoma would suggest that although mean T is higher in these patients, this measurement alone is of little practical value, whereas T/DHT ratio is a more reliable parameter in evaluating the androgen changes in these patients. The significance of these findings in relation to the aetiology of the disease is discussed. 相似文献
18.
Prostate carcinomas arise in 100% of Noble rats treated with estradiol and testosterone. We hypothesize that estrogens initiate prostate cancer mainly by formation of 4-catechol estrogens (CE), followed by their oxidation to catechol estrogen-3,4-quinones (CE-3,4-Q), which can react with DNA. To avoid cancer initiation, CE can be detoxified by catechol-O-methyltransferase (COMT), and CE-3,4-Q by conjugation with glutathione (GSH) or by reduction to CE, catalyzed by quinone reductase and/or cytochrome P450 reductase. To investigate the prostatic metabolism of estrogens, Noble rats were treated with the CE 4-hydroxyestradiol (4-OHE2) or estradiol-3,4-quinone (E2-3,4-Q), and CE metabolites and conjugates were analyzed in the four regions of the prostate, which differ in susceptibility to carcinoma formation. Following treatment of rats with 4-OHE2 (6 micromol/100 g body weight in 200 microl of trioctanoin/dimethylsulfoxide (4:1) by intraperitoneal injection) for 90 min, the non-susceptible ventral (VP) and anterior (AP) prostate had higher levels of 4-methoxyCE and GSH conjugates than the susceptible dorsolateral prostate (DLP) and periurethral prostate (PUP). After treatment with the same molar amount of E2-3,4-Q, the VP and AP contained more GSH conjugates, 4-CE and 4-methoxyCE than the susceptible DLP and PUP. These results suggest that prostate areas susceptible to carcinoma induction have less protection by COMT, GSH, and quinone reductase and/or cytochrome P450 reductase, favoring reaction of CE-3,4-Q with DNA, presumably to initiate cancer. 相似文献
19.
Suppression of prostate carcinogenesis by dietary supplementation of celecoxib in transgenic adenocarcinoma of the mouse prostate model 总被引:9,自引:0,他引:9
Gupta S Adhami VM Subbarayan M MacLennan GT Lewin JS Hafeli UO Fu P Mukhtar H 《Cancer research》2004,64(9):3334-3343
Epidemiological studies and clinical observations suggest that nonsteroidal anti-inflammatory drugs and certain selective cyclooxygenase (COX)-2 inhibitors may reduce the relative risk of clinically evident prostate cancer. This prompted us to investigate the chemopreventive potential of celecoxib, a selective COX-2 inhibitor, against prostate carcinogenesis in a transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Similar to prostate cancer in humans, prostate malignancies in TRAMP mice progress from precursor intraepithelial lesions, to invasive carcinoma that metastasizes to lymph nodes, liver, lungs, and occasionally to bone. The basal enzyme activity and protein expression of COX-2 is significantly higher (>4-fold) in the dorsolateral prostate of TRAMP mice up to 24 weeks of age compared with their nontransgenic littermates. Eight-week-old TRAMP mice were randomly divided and fed either control diet (AIN 76A) or a custom prepared AIN 76A diet containing 1500-ppm celecoxib ad libitum for 24 weeks, a dosage that would compare with the normal recommended dose for the treatment of human disease. Studies from two independent experiments, each consisting of 10 mice on test, showed that the cumulative incidence of prostate cancer development at 32 weeks of age in animals fed with AIN 76A diet was 100% (20 of 20) as observed by tumor palpation, whereas 65% (13 of 20), 35% (7 of 20), and 20% (4 of 20) of the animals exhibited distant site metastases to lymph nodes, lungs, and liver. Celecoxib supplementation to TRAMP mice from 8-32 weeks of age exhibited significant reduction in tumor development (5 of 20) with no signs of metastasis. Celecoxib feeding resulted in a significant decrease in prostate (56%; P < 0.0003) and genitourinary weight (48%; P < 0.008). Sequential magnetic resonance imaging analysis of celecoxib-fed mice documented lower prostate volume compared with the AIN 76A-fed group. Histopathological examination of celecoxib-fed animals showed reduced proliferation, and down-modulation of COX-2 and prostaglandin E2 levels in the dorsolateral prostate and plasma, respectively. These results correlated with retention of antimetastasis markers, viz E-cadherin, and alpha- and beta-catenin, along with a significant decrease in vascular endothelial growth factor protein expression. Celecoxib supplementation also resulted in enhanced in vivo apoptosis in the prostate as monitored by several techniques including a recently perfected technique of 99mTc-labeled annexin V in live animals followed by phosphor imaging. One striking observation in an additional study was that celecoxib feeding to mice with established tumors (16 weeks of age) significantly improved their overall survival (P = 0.014), compared with AIN 76A-fed group. Our findings suggest that celecoxib may be useful in chemoprevention of prostate cancer. 相似文献