Pub Date : 2000-01-01DOI: 10.1111/j.1525-1373.2000.22341.x
K. Nephew, E. Osborne, R. Lubet, C. Grubbs, S. Khan
Tamoxifen, toremifene, DHEA, and vorozole inhibit tumor growth in rodent mammary carcinoma models and are promising chemotherapeutic agents for use against breast cancer development. In the present study, the effect of these agents on uterine histomorphology following oral administration to mature ovary-intact rats (n = 380) was examined. Animals received diet only (control), tamoxifen (0.4 and 1 mg/kg of diet; 10 mg/kg BW by daily gavage), toremifene (3-30 mg/kg of diet), DHEA (24-2000 mg/kg of diet), or vorozole (0.08-1.25 mg/kg BW by daily gavage) for 28 days and were either sacrificed or returned to a basal diet and then sacrificed 21 days later. Treatment with toremifene (all doses) or tamoxifen (1 and 10 mg/kg) for 28 days produced a decrease (P<0.05) in overall uterine size and myometrial thickness; however, uterine luminal and glandular epithelia cell height increased (P<0.05) compared with control. These compartmentalized uterotrophic and antiestrogenic effects of toremifene and tamoxifen were still apparent after 21 days post-treatment. Administration of DHEA (2000 mg/kg of diet) for 28 days had dramatic uterotrophic effects, increasing (P<0.05) overall uterine size and stimulating all three uterine compartments (epithelia, stroma, and myometrium). The other doses of DHEA, however, were not uterotrophic. Interestingly, after removal of DHEA from the diet, uterine weight and myometrial thickness decreased (P<0.05). Vorozole (1.25 mg/kg) administration for 28 days had differential, compartmentalized uterine effects, producing an increase (P<0.05) in epithelial cell height, a decrease (P<0.05) in stromal size, but no change in myometrial thickness. After 21 days postadministration of vorozole, luminal epithelial cell height was increased (P<0.05) compared with control. The data suggest that oral administration of tamoxifen, toremifene, DHEA, and vorozole results in differential, compartmentalized effects in the uterus that are highly dependent on treatment dose. The data may have implications for risk assessment of these agents prior to administration to healthy, cancer-free women.
{"title":"Effects of oral administration of tamoxifen, toremifene, dehydroepiandrosterone, and vorozole on uterine histomorphology in the rat.","authors":"K. Nephew, E. Osborne, R. Lubet, C. Grubbs, S. Khan","doi":"10.1111/j.1525-1373.2000.22341.x","DOIUrl":"https://doi.org/10.1111/j.1525-1373.2000.22341.x","url":null,"abstract":"Tamoxifen, toremifene, DHEA, and vorozole inhibit tumor growth in rodent mammary carcinoma models and are promising chemotherapeutic agents for use against breast cancer development. In the present study, the effect of these agents on uterine histomorphology following oral administration to mature ovary-intact rats (n = 380) was examined. Animals received diet only (control), tamoxifen (0.4 and 1 mg/kg of diet; 10 mg/kg BW by daily gavage), toremifene (3-30 mg/kg of diet), DHEA (24-2000 mg/kg of diet), or vorozole (0.08-1.25 mg/kg BW by daily gavage) for 28 days and were either sacrificed or returned to a basal diet and then sacrificed 21 days later. Treatment with toremifene (all doses) or tamoxifen (1 and 10 mg/kg) for 28 days produced a decrease (P<0.05) in overall uterine size and myometrial thickness; however, uterine luminal and glandular epithelia cell height increased (P<0.05) compared with control. These compartmentalized uterotrophic and antiestrogenic effects of toremifene and tamoxifen were still apparent after 21 days post-treatment. Administration of DHEA (2000 mg/kg of diet) for 28 days had dramatic uterotrophic effects, increasing (P<0.05) overall uterine size and stimulating all three uterine compartments (epithelia, stroma, and myometrium). The other doses of DHEA, however, were not uterotrophic. Interestingly, after removal of DHEA from the diet, uterine weight and myometrial thickness decreased (P<0.05). Vorozole (1.25 mg/kg) administration for 28 days had differential, compartmentalized uterine effects, producing an increase (P<0.05) in epithelial cell height, a decrease (P<0.05) in stromal size, but no change in myometrial thickness. After 21 days postadministration of vorozole, luminal epithelial cell height was increased (P<0.05) compared with control. The data suggest that oral administration of tamoxifen, toremifene, DHEA, and vorozole results in differential, compartmentalized effects in the uterus that are highly dependent on treatment dose. The data may have implications for risk assessment of these agents prior to administration to healthy, cancer-free women.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73875868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-12-01DOI: 10.1046/J.1525-1373.1999.D01-144.X
A. C. Chan, C. Chow, D. Chiu
The generation of reactive oxygen species (ROS) is a steady-state cellular event in respiring cells. Their production can be grossly amplified in response to a variety of pathophysiological conditions such as inflammation, immunologic disorders, hypoxia, hyperoxia, metabolism of drug or alcohol, exposure to UV or therapeutic radiation, and deficiency in antioxidant vitamins. Uncontrolled production of ROS often leads to damage of cellular macromolecules (DNA, protein, and lipids) and other small antioxidant molecules. A number of major cellular defense mechanisms exist to neutralize and combat the damaging effects of these reactive substances. The enzymic system functions by direct or sequential removal of ROS (superoxide dismutase, catalase, and glutathione peroxidase), thereby terminating their activities. Metal binding proteins, targeted to bind iron and copper ions, ensure that these Fenton metals are cryptic. Nonenzymic defense consists of scavenging molecules that are endogenously produced (GSH, ubiquinols, uric acid) or those derived from the diet (vitamins C and E, lipoic acid, selenium, riboflavin, zinc, and the carotenoids). These antioxidant nutrients occupy distinct cellular compartments and among them, there are active recycling. For example, oxidized vitamin E (tocopheroxy radical) has been shown to be regenerated by ascorbate, GSH, lipoic acid, or ubiquinols. GSH disulfides (GSSG) can be regenerated by GSSG reductase (a riboflavin-dependent protein), and enzymic pathways have been identified for the recycling of ascorbate radical and dehydroascorbate. The electrons that are used to fuel these recycling reactions (NADH and NADPH) are ultimately derived from the oxidation of foods. Sickle cell anemia, thalassemia, and glucose-6-phosphate-dehydrogenase deficiency are all hereditary disorders with higher potential for oxidative damage due to chronic redox imbalance in red cells that often results in clinical manifestation of mild to serve hemolysis in patients with these disorders. The release of hemoglobin during hemolysis and the subsequent therapeutic transfusion in some cases lead to systemic iron overloading that further potentiates the generation of ROS. Antioxidant status in anemia will be examined, and the potential application of antioxidant treatment as an adjunct therapy under these conditions will be discussed.
{"title":"Interaction of antioxidants and their implication in genetic anemia.","authors":"A. C. Chan, C. Chow, D. Chiu","doi":"10.1046/J.1525-1373.1999.D01-144.X","DOIUrl":"https://doi.org/10.1046/J.1525-1373.1999.D01-144.X","url":null,"abstract":"The generation of reactive oxygen species (ROS) is a steady-state cellular event in respiring cells. Their production can be grossly amplified in response to a variety of pathophysiological conditions such as inflammation, immunologic disorders, hypoxia, hyperoxia, metabolism of drug or alcohol, exposure to UV or therapeutic radiation, and deficiency in antioxidant vitamins. Uncontrolled production of ROS often leads to damage of cellular macromolecules (DNA, protein, and lipids) and other small antioxidant molecules. A number of major cellular defense mechanisms exist to neutralize and combat the damaging effects of these reactive substances. The enzymic system functions by direct or sequential removal of ROS (superoxide dismutase, catalase, and glutathione peroxidase), thereby terminating their activities. Metal binding proteins, targeted to bind iron and copper ions, ensure that these Fenton metals are cryptic. Nonenzymic defense consists of scavenging molecules that are endogenously produced (GSH, ubiquinols, uric acid) or those derived from the diet (vitamins C and E, lipoic acid, selenium, riboflavin, zinc, and the carotenoids). These antioxidant nutrients occupy distinct cellular compartments and among them, there are active recycling. For example, oxidized vitamin E (tocopheroxy radical) has been shown to be regenerated by ascorbate, GSH, lipoic acid, or ubiquinols. GSH disulfides (GSSG) can be regenerated by GSSG reductase (a riboflavin-dependent protein), and enzymic pathways have been identified for the recycling of ascorbate radical and dehydroascorbate. The electrons that are used to fuel these recycling reactions (NADH and NADPH) are ultimately derived from the oxidation of foods. Sickle cell anemia, thalassemia, and glucose-6-phosphate-dehydrogenase deficiency are all hereditary disorders with higher potential for oxidative damage due to chronic redox imbalance in red cells that often results in clinical manifestation of mild to serve hemolysis in patients with these disorders. The release of hemoglobin during hemolysis and the subsequent therapeutic transfusion in some cases lead to systemic iron overloading that further potentiates the generation of ROS. Antioxidant status in anemia will be examined, and the potential application of antioxidant treatment as an adjunct therapy under these conditions will be discussed.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90366487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-02DOI: 10.1111/J.1525-1373.1999.09991.PP.X
S. Kaal, F. V. D. van den Hoogen, E. D. De Jong, H. Viëtor
The strong female predilection of systemic sclerosis, especially in women after their childbearing years, and the clinical and histopathological similarities with chronic graft-versus-host disease make systemic sclerosis an interesting subject of debate. Recent studies concerning the pathogenesis of this disease demonstrated the persistence of fetal cells in the maternal circulation in a majority of female patients. How or whether microchimerism is involved in the pathogenesis of systemic sclerosis remains to be elucidated. The present paper reviews the recent findings on the subject.
{"title":"Systemic sclerosis: new insights in autoimmunity.","authors":"S. Kaal, F. V. D. van den Hoogen, E. D. De Jong, H. Viëtor","doi":"10.1111/J.1525-1373.1999.09991.PP.X","DOIUrl":"https://doi.org/10.1111/J.1525-1373.1999.09991.PP.X","url":null,"abstract":"The strong female predilection of systemic sclerosis, especially in women after their childbearing years, and the clinical and histopathological similarities with chronic graft-versus-host disease make systemic sclerosis an interesting subject of debate. Recent studies concerning the pathogenesis of this disease demonstrated the persistence of fetal cells in the maternal circulation in a majority of female patients. How or whether microchimerism is involved in the pathogenesis of systemic sclerosis remains to be elucidated. The present paper reviews the recent findings on the subject.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74678004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-02DOI: 10.1111/J.1525-1373.1999.09997.PP.X
J. Drisko, T. Faidley, D. Zhang, T. McDonald, S. Nicolich, D. Hora, P. Cunningham, C. Li, E. Rickes, L. Mcnamara, C. Chang, R. Smith, G. Hickey
The activity of the growth hormone secretagog, L-163,255, on growth hormone (GH), growth hormone-releasing factor (GRF), and somatostatin (SRIF) levels was evaluated in a porcine model of hypophyseal portal blood (HPB) collection. Young, castrated pigs had HPB and jugular blood collected for approximately 300 min. The blood collection was divided into discrete periods: baseline (BL) approximately 180 min; GH response period (RSP) approximately 90 min; and positive control period following a GRF bolus, 30 min. RSP was divided into a dominant response period (DOM) and a tail (TL). The spontaneous relationship between HPB GRF and SRIF and peripheral GH during BL has been reported (Proc Soc Exp Biol Med 217:188-196, 1998). The apex of the GH pulse resulting from L-163,255 administration was nonrandomly associated (P < 0.05) with descending periods of SRIF troughs. Frequency and amplitude of GRF and SRIF pulses, and frequency and depth of SRIF troughs were not different between BL and the beginning of DOM (the 20-30 min of GH increase). GH AUC was significantly greater (P < 0.05) for DOM compared to BL and TL, and for TL compared to BL. GRF AUC tended to be greater (P < 0.1) for RSP compared to BL, but the majority of the increase was in the TL period. There were no significant differences in the SRIF AUCs between the sampling periods. Furthermore, in a separate experiment, fos activity (a marker of neuronal activation) in the hypothalamus of pigs was examined after either L-163,255 (1x or 4x), isotonic saline (control), or hypertonic saline (positive control) administration. There were no differences in fos activity in the GRF, SRIF, or CRH immunopositive neurons between L-163,255 treatment and control. The pituitaries of the L-163,255-treated pigs showed marked fos activation compared to the controls. In conclusion, L-163,255 in pigs has its primary effect at the level of the anterior pituitary.
{"title":"Administration of a nonpeptidyl growth hormone secretagogue, L-163, 255, changes somatostatin pattern, but has no effect on patterns of growth hormone-releasing factor in the hypophyseal-portal circulation of the conscious pig.","authors":"J. Drisko, T. Faidley, D. Zhang, T. McDonald, S. Nicolich, D. Hora, P. Cunningham, C. Li, E. Rickes, L. Mcnamara, C. Chang, R. Smith, G. Hickey","doi":"10.1111/J.1525-1373.1999.09997.PP.X","DOIUrl":"https://doi.org/10.1111/J.1525-1373.1999.09997.PP.X","url":null,"abstract":"The activity of the growth hormone secretagog, L-163,255, on growth hormone (GH), growth hormone-releasing factor (GRF), and somatostatin (SRIF) levels was evaluated in a porcine model of hypophyseal portal blood (HPB) collection. Young, castrated pigs had HPB and jugular blood collected for approximately 300 min. The blood collection was divided into discrete periods: baseline (BL) approximately 180 min; GH response period (RSP) approximately 90 min; and positive control period following a GRF bolus, 30 min. RSP was divided into a dominant response period (DOM) and a tail (TL). The spontaneous relationship between HPB GRF and SRIF and peripheral GH during BL has been reported (Proc Soc Exp Biol Med 217:188-196, 1998). The apex of the GH pulse resulting from L-163,255 administration was nonrandomly associated (P < 0.05) with descending periods of SRIF troughs. Frequency and amplitude of GRF and SRIF pulses, and frequency and depth of SRIF troughs were not different between BL and the beginning of DOM (the 20-30 min of GH increase). GH AUC was significantly greater (P < 0.05) for DOM compared to BL and TL, and for TL compared to BL. GRF AUC tended to be greater (P < 0.1) for RSP compared to BL, but the majority of the increase was in the TL period. There were no significant differences in the SRIF AUCs between the sampling periods. Furthermore, in a separate experiment, fos activity (a marker of neuronal activation) in the hypothalamus of pigs was examined after either L-163,255 (1x or 4x), isotonic saline (control), or hypertonic saline (positive control) administration. There were no differences in fos activity in the GRF, SRIF, or CRH immunopositive neurons between L-163,255 treatment and control. The pituitaries of the L-163,255-treated pigs showed marked fos activation compared to the controls. In conclusion, L-163,255 in pigs has its primary effect at the level of the anterior pituitary.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81575175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-02DOI: 10.1111/J.1525-1373.1999.09992.PP.X
Kathryn E. Boyd, P. Farnham
Disregulation of many transcription factors is associated with the development of human neoplasia. Transcription factors regulate cell growth, differentiation, and apoptosis by binding to specific DNA sequences within the promoter regions of growth-regulatory genes and modulating expression of these genes. This simple model is complicated by the fact that mammalian transcription factors are often members of large protein families that bind to similar DNA sequences. This raises the question as to whether members of a particular family regulate expression of overlapping or unique sets of genes. This review is focused on addressing this question using the Ets, Myc, and E2F transcription factor families as examples. Deregulated activity of some, but not all, members of these families is observed in cancer. Here, we summarize the data illustrating the concept that binding of individual members of these families of factors can result in promoter-specific responses and review the studies that have provided some insight into how target gene specificity is achieved. Since, for all of these oncogenic transcription factors, it remains unclear exactly which target genes are important in neoplasia, we have also reviewed the many approaches researchers are using to identify target genes of the various Ets, Myc, and E2F family members.
{"title":"Identification of target genes of oncogenic transcription factors.","authors":"Kathryn E. Boyd, P. Farnham","doi":"10.1111/J.1525-1373.1999.09992.PP.X","DOIUrl":"https://doi.org/10.1111/J.1525-1373.1999.09992.PP.X","url":null,"abstract":"Disregulation of many transcription factors is associated with the development of human neoplasia. Transcription factors regulate cell growth, differentiation, and apoptosis by binding to specific DNA sequences within the promoter regions of growth-regulatory genes and modulating expression of these genes. This simple model is complicated by the fact that mammalian transcription factors are often members of large protein families that bind to similar DNA sequences. This raises the question as to whether members of a particular family regulate expression of overlapping or unique sets of genes. This review is focused on addressing this question using the Ets, Myc, and E2F transcription factor families as examples. Deregulated activity of some, but not all, members of these families is observed in cancer. Here, we summarize the data illustrating the concept that binding of individual members of these families of factors can result in promoter-specific responses and review the studies that have provided some insight into how target gene specificity is achieved. Since, for all of these oncogenic transcription factors, it remains unclear exactly which target genes are important in neoplasia, we have also reviewed the many approaches researchers are using to identify target genes of the various Ets, Myc, and E2F family members.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87756095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-02DOI: 10.1111/J.1525-1373.1999.09994.PP.X
C. Phelps, D. Hurley
Studies of mutant mice that are growth hormone (GH)- and prolactin (PRL)-deficient have provided evidence that these pituitary hormones have trophic, as well as dynamic, feedback effects on the hypothalamic neurons that regulate GH and PRL secretion (1). This review examines further evidence, from those animals and from recent transgenic models, for GH and PRL effects on neuronal differentiation. Characterization of the Ames dwarf (Prop-1) mutation and discovery of other genes important to pituitary differentiation reveal an expression sequence of transcription factors, Hesx1 (Rpx) to P-Lim to Prop-1 to Pit-1, that heralds influence on hypothalamic differentiation. Occasional expression of GH and PRL in the Ames dwarf pituitary may result from the "partial loss of function" nature of the Ames Prop-1 mutation. In transgenic mice with moderately or extremely elevated GH levels, neurons that regulate GH exhibit respective maximum and minimum expression and cell number in inhibitory somatostatin (SRIH) and in stimulatory GH-releasing hormone (GHRH). The phenomenon is inverted in GH-lacking dwarfs, and patterns of SRIH underexpression and GHRH overexpression are established early in postnatal development. The differentiation of PRL-inhibiting dopaminergic (DA) neurons is supported not only by PRL, but by human GH, which is lactogenic in rodents. Transgenic mice with peripherally expressed hGH have increased numbers of DA neurons, as opposed to the decreased DA population in PRL-deficient dwarf mice. Rats engineered to express hGH in GHRH neurons do not show this increase, whereas spontaneously GH-deficient dwarf rats show increased DA neuron number. These findings may be explained by feedback on neurons that co-express GHRH and DA. Current studies suggest that Snell (Pit-1) dwarf mice show a more severe and earlier DA neuron deficiency than Ames dwarfs, and that PRL feedback must occur prior to 20 days of postnatal age to maintain the DA neuronal phenotype. Insights into the mechanisms of GH and PRL effects on hypophysiotropic neurons include receptor localization on identified neuronal phenotypes, including intermediate neurons that mediate dynamic feedback, and elucidation of signal transduction pathways for GH and PRL in peripheral cell types. New transgenic models of altered GH, PRL, or receptor expression offer further study of neurotrophic effects.
{"title":"Pituitary hormones as neurotrophic signals: update on hypothalamic differentiation in genetic models of altered feedback.","authors":"C. Phelps, D. Hurley","doi":"10.1111/J.1525-1373.1999.09994.PP.X","DOIUrl":"https://doi.org/10.1111/J.1525-1373.1999.09994.PP.X","url":null,"abstract":"Studies of mutant mice that are growth hormone (GH)- and prolactin (PRL)-deficient have provided evidence that these pituitary hormones have trophic, as well as dynamic, feedback effects on the hypothalamic neurons that regulate GH and PRL secretion (1). This review examines further evidence, from those animals and from recent transgenic models, for GH and PRL effects on neuronal differentiation. Characterization of the Ames dwarf (Prop-1) mutation and discovery of other genes important to pituitary differentiation reveal an expression sequence of transcription factors, Hesx1 (Rpx) to P-Lim to Prop-1 to Pit-1, that heralds influence on hypothalamic differentiation. Occasional expression of GH and PRL in the Ames dwarf pituitary may result from the \"partial loss of function\" nature of the Ames Prop-1 mutation. In transgenic mice with moderately or extremely elevated GH levels, neurons that regulate GH exhibit respective maximum and minimum expression and cell number in inhibitory somatostatin (SRIH) and in stimulatory GH-releasing hormone (GHRH). The phenomenon is inverted in GH-lacking dwarfs, and patterns of SRIH underexpression and GHRH overexpression are established early in postnatal development. The differentiation of PRL-inhibiting dopaminergic (DA) neurons is supported not only by PRL, but by human GH, which is lactogenic in rodents. Transgenic mice with peripherally expressed hGH have increased numbers of DA neurons, as opposed to the decreased DA population in PRL-deficient dwarf mice. Rats engineered to express hGH in GHRH neurons do not show this increase, whereas spontaneously GH-deficient dwarf rats show increased DA neuron number. These findings may be explained by feedback on neurons that co-express GHRH and DA. Current studies suggest that Snell (Pit-1) dwarf mice show a more severe and earlier DA neuron deficiency than Ames dwarfs, and that PRL feedback must occur prior to 20 days of postnatal age to maintain the DA neuronal phenotype. Insights into the mechanisms of GH and PRL effects on hypophysiotropic neurons include receptor localization on identified neuronal phenotypes, including intermediate neurons that mediate dynamic feedback, and elucidation of signal transduction pathways for GH and PRL in peripheral cell types. New transgenic models of altered GH, PRL, or receptor expression offer further study of neurotrophic effects.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86867016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1046/J.1525-1373.1999.D01-122.X
G. Mizejewski
Tumor cells are characterized by uncontrolled growth, invasion to surrounding tissues, and metastatic spread to distant sites. Mortality from cancer is often due to metastasis since surgical removal of tumors can enhance and prolong survival. The integrins constitute a family of transmembrane receptor proteins composed of heterodimeric complexes of noncovalently linked alpha and beta chains. Integrins function in cell-to-cell and cell-to-extracellular matrix (ECM) adhesive interactions and transduce signals from the ECM to the cell interior and vice versa. Hence, the integrins mediate the ECM influence on cell growth and differentiation. Since these properties implicate integrin involvement in cell migration, invasion, intra- and extra-vasation, and platelet interaction, a role for integrins in tumor growth and metastasis is obvious. These findings are underpinned by observations that the integrins are linked to the actin cytoskeleton involving talin, vinculin, and alpha-actinin as intermediaries. Such cytoskeletal changes can be manifested by rounded cell morphology, which is often coincident with tumor transformation via decreased or increased integrin expression patterns. For the various types of cancers, different changes in integrin expression are further associated with tumor growth and metastasis. Tumor progression leading to metastasis appears to involve equipping cancer cells with the appropriate adhesive (integrin) phenotype for interaction with the ECM. Therapies directed at influencing integrin cell expression and function are presently being explored for inhibition of tumor growth, metastasis, and angiogenesis. Such therapeutic strategies include anti-integrin monoclonal antibodies, peptidic inhibitors (cyclic and linear), calcium-binding protein antagonists, proline analogs, apoptosis promotors, and antisense oligonucleotides. Moreover, platelet aggregation induced by tumor cells, which facilitates metastatic spread, can be inhibited by the disintegrins, a family of viper venom-like peptides. Therefore, adhesion molecules from the integrin family and components of angiogenesis might be useful as tumor progression markers for prognostic and for diagnostic purposes. Development of integrin cell expression profiles for individual tumors may have further potential in identifying a cell surface signature for a specific tumor type and/or stage. Thus, recent advances in elucidating the structure, function, ECM binding, and signaling pathways of the integrins have led to new and exciting modalities for cancer therapeutics and diagnoses.
{"title":"Role of integrins in cancer: survey of expression patterns.","authors":"G. Mizejewski","doi":"10.1046/J.1525-1373.1999.D01-122.X","DOIUrl":"https://doi.org/10.1046/J.1525-1373.1999.D01-122.X","url":null,"abstract":"Tumor cells are characterized by uncontrolled growth, invasion to surrounding tissues, and metastatic spread to distant sites. Mortality from cancer is often due to metastasis since surgical removal of tumors can enhance and prolong survival. The integrins constitute a family of transmembrane receptor proteins composed of heterodimeric complexes of noncovalently linked alpha and beta chains. Integrins function in cell-to-cell and cell-to-extracellular matrix (ECM) adhesive interactions and transduce signals from the ECM to the cell interior and vice versa. Hence, the integrins mediate the ECM influence on cell growth and differentiation. Since these properties implicate integrin involvement in cell migration, invasion, intra- and extra-vasation, and platelet interaction, a role for integrins in tumor growth and metastasis is obvious. These findings are underpinned by observations that the integrins are linked to the actin cytoskeleton involving talin, vinculin, and alpha-actinin as intermediaries. Such cytoskeletal changes can be manifested by rounded cell morphology, which is often coincident with tumor transformation via decreased or increased integrin expression patterns. For the various types of cancers, different changes in integrin expression are further associated with tumor growth and metastasis. Tumor progression leading to metastasis appears to involve equipping cancer cells with the appropriate adhesive (integrin) phenotype for interaction with the ECM. Therapies directed at influencing integrin cell expression and function are presently being explored for inhibition of tumor growth, metastasis, and angiogenesis. Such therapeutic strategies include anti-integrin monoclonal antibodies, peptidic inhibitors (cyclic and linear), calcium-binding protein antagonists, proline analogs, apoptosis promotors, and antisense oligonucleotides. Moreover, platelet aggregation induced by tumor cells, which facilitates metastatic spread, can be inhibited by the disintegrins, a family of viper venom-like peptides. Therefore, adhesion molecules from the integrin family and components of angiogenesis might be useful as tumor progression markers for prognostic and for diagnostic purposes. Development of integrin cell expression profiles for individual tumors may have further potential in identifying a cell surface signature for a specific tumor type and/or stage. Thus, recent advances in elucidating the structure, function, ECM binding, and signaling pathways of the integrins have led to new and exciting modalities for cancer therapeutics and diagnoses.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74988655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-10-01DOI: 10.1111/J.1525-1373.1999.09999.PP.X
K. Plaut, R. Maple, C. Vyas, S. Munaim, A. Darling, T. Casey, J. Alberts
The effects of spaceflight on mammary metabolism of 10 pregnant rats was measured on Day 20 of pregnancy and after parturition. Rats were flown on the space shuttle from Day 11 through Day 20 of pregnancy. After their return to earth, glucose oxidation to carbon dioxide increased 43% (P < 0.05), and incorporation into fatty acids increased 300% (P < 0.005) compared to controls. It is unclear whether the enhanced glucose use is due to spaceflight or a response to landing. Casein mRNA and gross histology were not altered at Day 20 of pregnancy. Six rats gave birth (on Day 22 to 23 of pregnancy) and mammary metabolic activity was measured immediately postpartum. The earlier effects of spaceflight were no longer apparent. There was also no difference in expression of beta-casein mRNA. It is clear from these studies that spaceflight does not impair the normal development of the mammary gland, its ability to use glucose, nor the ability to express mRNA for a major milk protein.
{"title":"The effects of spaceflight on mammary metabolism in pregnant rats.","authors":"K. Plaut, R. Maple, C. Vyas, S. Munaim, A. Darling, T. Casey, J. Alberts","doi":"10.1111/J.1525-1373.1999.09999.PP.X","DOIUrl":"https://doi.org/10.1111/J.1525-1373.1999.09999.PP.X","url":null,"abstract":"The effects of spaceflight on mammary metabolism of 10 pregnant rats was measured on Day 20 of pregnancy and after parturition. Rats were flown on the space shuttle from Day 11 through Day 20 of pregnancy. After their return to earth, glucose oxidation to carbon dioxide increased 43% (P < 0.05), and incorporation into fatty acids increased 300% (P < 0.005) compared to controls. It is unclear whether the enhanced glucose use is due to spaceflight or a response to landing. Casein mRNA and gross histology were not altered at Day 20 of pregnancy. Six rats gave birth (on Day 22 to 23 of pregnancy) and mammary metabolic activity was measured immediately postpartum. The earlier effects of spaceflight were no longer apparent. There was also no difference in expression of beta-casein mRNA. It is clear from these studies that spaceflight does not impair the normal development of the mammary gland, its ability to use glucose, nor the ability to express mRNA for a major milk protein.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87057641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-09-01DOI: 10.1111/J.1525-1373.1999.10000.PP.X
B. Martínez-Nieves, Joseph C. Dunbar
Diabetes is associated with impaired vascular dilatatory responses that appear to be influenced by sex as well as diabetic state. Therefore, we hypothesized that vascular and sympathetic control function exhibit a greater deterioration following the induction of diabetes in female than in male rats. We conducted a comparative determination of the effect of sodium nitroprusside (SNP, a nitrous oxide donor) and that of an alpha1-adrenergic antagonist, prazosin, on selective vascular flows, mean arterial pressure (MAP), and heart rate (HR), in female and male normal and diabetic rats. Rats were made diabetic using streptozotocin (50 mg/kg, iv) and maintained for 5-6 weeks. Following anesthesia with urethane/alpha-chloralose, the femoral artery and vein were cannulated for recording and sampling. Flow probes were placed on the iliac, renal, and superior mesenteric arteries. SNP (1, 5, 10, and 20 microg/kg) infusions resulted in a dose-dependent decrease in MAP in normal and diabetic rats. The decrease in MAP in normal males was 37% less at the 20 microg/kg concentration of SNP when compared to normal females. The HR was not significantly changed in response to the hypotensive effect of SNP; however, reflex tachycardia was more prominent in diabetic males. The vascular conductance (flow/MAP) was increased by SNP in normal and diabetic rats in a dose-dependent fashion; however, the responsiveness was decreased in the iliac and superior mesenteric and increased in the renal arteries in diabetics when compared to normals. Diabetic males were 42% and 28% less responsive to SNP in the iliac and superior mesenteric arteries, respectively. On the other hand, diabetic females were 1.5-fold more responsive in the renal artery when compared to normals. Prazosin (4 mg/kg) decreased the MAP in normal and diabetic rats to a comparable degree. Prazosin increased the vascular conductance in all three vascular beds in normal and diabetic rats with the greater increase occurring in the iliac (118%) and superior mesenteric (110%) arteries. We concluded that diabetes is associated with an increased response to NO in the renal vessels and a decreased response in the iliac and superior mesenteric vessels in both females and males. alpha-Adrenergic tone was greatest in diabetic female and male rats. This study suggests that decreased vascular flow in diabetes is a result of a combination of decreased sensitivity to NO and increased adrenergic tone.
{"title":"Vascular dilatatory responses to sodium nitroprusside (SNP) and alpha-adrenergic antagonism in female and male normal and diabetic rats.","authors":"B. Martínez-Nieves, Joseph C. Dunbar","doi":"10.1111/J.1525-1373.1999.10000.PP.X","DOIUrl":"https://doi.org/10.1111/J.1525-1373.1999.10000.PP.X","url":null,"abstract":"Diabetes is associated with impaired vascular dilatatory responses that appear to be influenced by sex as well as diabetic state. Therefore, we hypothesized that vascular and sympathetic control function exhibit a greater deterioration following the induction of diabetes in female than in male rats. We conducted a comparative determination of the effect of sodium nitroprusside (SNP, a nitrous oxide donor) and that of an alpha1-adrenergic antagonist, prazosin, on selective vascular flows, mean arterial pressure (MAP), and heart rate (HR), in female and male normal and diabetic rats. Rats were made diabetic using streptozotocin (50 mg/kg, iv) and maintained for 5-6 weeks. Following anesthesia with urethane/alpha-chloralose, the femoral artery and vein were cannulated for recording and sampling. Flow probes were placed on the iliac, renal, and superior mesenteric arteries. SNP (1, 5, 10, and 20 microg/kg) infusions resulted in a dose-dependent decrease in MAP in normal and diabetic rats. The decrease in MAP in normal males was 37% less at the 20 microg/kg concentration of SNP when compared to normal females. The HR was not significantly changed in response to the hypotensive effect of SNP; however, reflex tachycardia was more prominent in diabetic males. The vascular conductance (flow/MAP) was increased by SNP in normal and diabetic rats in a dose-dependent fashion; however, the responsiveness was decreased in the iliac and superior mesenteric and increased in the renal arteries in diabetics when compared to normals. Diabetic males were 42% and 28% less responsive to SNP in the iliac and superior mesenteric arteries, respectively. On the other hand, diabetic females were 1.5-fold more responsive in the renal artery when compared to normals. Prazosin (4 mg/kg) decreased the MAP in normal and diabetic rats to a comparable degree. Prazosin increased the vascular conductance in all three vascular beds in normal and diabetic rats with the greater increase occurring in the iliac (118%) and superior mesenteric (110%) arteries. We concluded that diabetes is associated with an increased response to NO in the renal vessels and a decreased response in the iliac and superior mesenteric vessels in both females and males. alpha-Adrenergic tone was greatest in diabetic female and male rats. This study suggests that decreased vascular flow in diabetes is a result of a combination of decreased sensitivity to NO and increased adrenergic tone.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74734849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-01-01DOI: 10.1046/j.1525-1373.1999.d01-82.x
R. Near, R. Matulka, K. Mann, S. Gogate, A. Trombino, D. Sherr
Polycyclic aromatic hydrocarbons (PAH) are environmental chemicals that mediate immunosuppression. In long-term bone marrow B-cell lymphopoiesis models, PAH induce apoptosis in immature (preB) lymphocytes. Since the biologic function of PAH is often mediated by the aryl hydrocarbon receptor/transcription factor (AhR), the role of the AhR or AhR-regulated genes was assessed in preB cell apoptosis. Specifically, a bone marrow-derived preB cell line (BU-11) was cultured on monolayers of the AhR + bone marrow-derived stromal cell line BMS2, hepatoma sublines that express various levels of AhR activity (Hepa-1c1c7 and variants), AhR+ thymic epithelial cells, and primary bone marrow stromal cells from wildtype or AhR-/- mice. Cultures were treated with one of two prototypic PAH, 7,12-dimethylbenz[a] anthracene (DMBA) or benz[a]pyrene (B[a]P), and the percentage of cells undergoing apoptosis measured. The data demonstrated that: 1) bone marrow- and hepatic-derived stromal/adherent cells support preB cell growth and regulate apoptosis induced by DMBA or B[a]P; 2) B[a]P is more effective than DMBA when preB cells are maintained on Hepa-1c1c7 monolayers than when maintained on BMS2 monolayers; 3) DMBA is more effective than B[a]P when preB cells are cultured on BMS2 monolayers; 4) alpha-naphthoflavone, an AhR antagonist and cytochrome P-450 inhibitor, blocks preB cell apoptosis in both BU-11/Hepa-1c1c7 and BU-11/BMS2 cultures; 5) although preB cells grow well in Hepa-1c1c7 or BMS2 supernatants, addition of PAH in the absence of hepatic- or bone marrow-derived adherent cells does not result in preB cell apoptosis; 6) preB cell apoptosis is dependent on AhR activity in adherent hepatic- or bone marrow-derived stromal cells; and 7) apoptosis is induced by DMBA when preB cells are maintained on primary bone marrow stromal cell monolayers from wildtype but not from AhR-/- mice. Collectively, the data indicated that AhR-regulated activities in the hematopoietic microenvironment influence the susceptibility of immature lymphocytes to low-dose PAH exposure.
{"title":"Regulation of preB cell apoptosis by aryl hydrocarbon receptor/transcription factor-expressing stromal/adherent cells.","authors":"R. Near, R. Matulka, K. Mann, S. Gogate, A. Trombino, D. Sherr","doi":"10.1046/j.1525-1373.1999.d01-82.x","DOIUrl":"https://doi.org/10.1046/j.1525-1373.1999.d01-82.x","url":null,"abstract":"Polycyclic aromatic hydrocarbons (PAH) are environmental chemicals that mediate immunosuppression. In long-term bone marrow B-cell lymphopoiesis models, PAH induce apoptosis in immature (preB) lymphocytes. Since the biologic function of PAH is often mediated by the aryl hydrocarbon receptor/transcription factor (AhR), the role of the AhR or AhR-regulated genes was assessed in preB cell apoptosis. Specifically, a bone marrow-derived preB cell line (BU-11) was cultured on monolayers of the AhR + bone marrow-derived stromal cell line BMS2, hepatoma sublines that express various levels of AhR activity (Hepa-1c1c7 and variants), AhR+ thymic epithelial cells, and primary bone marrow stromal cells from wildtype or AhR-/- mice. Cultures were treated with one of two prototypic PAH, 7,12-dimethylbenz[a] anthracene (DMBA) or benz[a]pyrene (B[a]P), and the percentage of cells undergoing apoptosis measured. The data demonstrated that: 1) bone marrow- and hepatic-derived stromal/adherent cells support preB cell growth and regulate apoptosis induced by DMBA or B[a]P; 2) B[a]P is more effective than DMBA when preB cells are maintained on Hepa-1c1c7 monolayers than when maintained on BMS2 monolayers; 3) DMBA is more effective than B[a]P when preB cells are cultured on BMS2 monolayers; 4) alpha-naphthoflavone, an AhR antagonist and cytochrome P-450 inhibitor, blocks preB cell apoptosis in both BU-11/Hepa-1c1c7 and BU-11/BMS2 cultures; 5) although preB cells grow well in Hepa-1c1c7 or BMS2 supernatants, addition of PAH in the absence of hepatic- or bone marrow-derived adherent cells does not result in preB cell apoptosis; 6) preB cell apoptosis is dependent on AhR activity in adherent hepatic- or bone marrow-derived stromal cells; and 7) apoptosis is induced by DMBA when preB cells are maintained on primary bone marrow stromal cell monolayers from wildtype but not from AhR-/- mice. Collectively, the data indicated that AhR-regulated activities in the hematopoietic microenvironment influence the susceptibility of immature lymphocytes to low-dose PAH exposure.","PeriodicalId":20618,"journal":{"name":"Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85749842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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