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Stacey RB, Kock ND, D'Agostino RB, Torti FM, Eckman DM, Sane DC, Workman S, Lane KS, Hundley WG. DOXORUBICIN ASSOCIATED CHANGES IN CORONARY ARTERY HISTOLOGY. J Am Coll Cardiol 2011. [DOI: 10.1016/s0735-1097(11)61591-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Arnold AC, Shaltout HA, Gilliam-Davis S, Kock ND, Diz DI. Autonomic control of the heart is altered in Sprague-Dawley rats with spontaneous hydronephrosis. Am J Physiol Heart Circ Physiol 2011; 300:H2206-13. [PMID: 21460193 DOI: 10.1152/ajpheart.01263.2010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The renal medulla plays an important role in cardiovascular regulation, through interactions with the autonomic nervous system. Hydronephrosis is characterized by substantial loss of renal medullary tissue. However, whether alterations in autonomic control of the heart are observed in this condition is unknown. Thus we assessed resting hemodynamics and baroreflex sensitivity (BRS) for control of heart rate in urethane/chloralose-anesthetized Sprague-Dawley rats with normal or hydronephrotic kidneys. While resting arterial pressure was similar, heart rate was higher in rats with hydronephrosis (290 ± 12 normal vs. 344 ± 11 mild/moderate vs. 355 ± 13 beats/min severe; P < 0.05). The evoked BRS to increases, but not decreases, in pressure was lower in hydronephrotic rats (1.06 ± 0.06 normal vs. 0.72 ± 0.10 mild/moderate vs. 0.63 ± 0.07 ms/mmHg severe; P < 0.05). Spectral analysis methods confirmed reduced parasympathetic function in hydronephrosis, with no differences in measures of indirect sympathetic activity among conditions. As a secondary aim, we investigated whether autonomic dysfunction in hydronephrosis is associated with activation of the renin-angiotensin system (RAS). There were no differences in circulating angiotensin peptides among conditions, suggesting that the impaired autonomic function in hydronephrosis is independent of peripheral RAS activation. A possible site for angiotensin II-mediated BRS impairment is the solitary tract nucleus (NTS). In normal and mild/moderate hydronephrotic rats, NTS administration of the angiotensin II type 1 receptor antagonist candesartan significantly improved the BRS, suggesting that angiotensin II provides tonic suppression to the baroreflex. In contrast, angiotensin II blockade produced no significant effect in severe hydronephrosis, indicating that at least within the NTS baroreflex suppression in these animals is independent of angiotensin II.
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Appt SE, Clarkson TB, Hoyer PB, Kock ND, Goode AK, May MC, Persyn JT, Vail NK, Ethun KF, Chen H, Sen N, Kaplan JR. Experimental induction of reduced ovarian reserve in a nonhuman primate model (Macaca fascicularis). Comp Med 2010; 60:380-8. [PMID: 21262124 PMCID: PMC2958207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 04/04/2010] [Accepted: 07/10/2010] [Indexed: 05/30/2023]
Abstract
Chronic diseases including coronary heart disease and osteoporosis represent a substantial health burden to postmenopausal women, yet the initiation of these conditions and their relationships with reproductive aging remain poorly understood. This situation is due, in part, to the lack of animal models reflecting ovarian and hormonal characteristics of peri- and postmenopausal women. Ovaries of women approaching menopause are nearly depleted of primordial follicles but retain a pool of larger developing follicles and androgen-producing stroma, a condition known as reduced ovarian reserve (ROR). The long-term goal of the research presented here was to create a monkey model of reproductive aging, beginning with ROR and progressing to perimenopause and finally postmenopause. Here we sought to develop a method to reduce primordial follicles in cynomolgus monkeys (Macaca fascicularis) and document hormonal changes associated with follicle reduction or ROR. At 30 d after surgical placement of a biodegradable fiber containing approximately 200 mg of 4-vinlycyclohexene diepoxide (VCD) next to one ovary in each of 8 monkeys, primordial follicles were reduced by approximately 70%, with a corresponding decrease (83%) in antimüllerian hormone (AMH, a serum marker of ovarian follicle numbers). At 4 mo after VCD-treatment of both ovaries in 29 monkeys (approximately 200 mg VCD per ovary), AMH was reduced 56% from baseline, testosterone was unchanged, and follicular phase estradiol was slightly increased. These data indicate that VCD treatment markedly reduced primordial follicles while preserving larger estradiol- and testosterone-producing follicles and ovarian stroma, a condition that mimics ROR in women.
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Yang Q, Kock ND. Effects of dietary fish oil on intestinal adaptation in 20-day-old weanling rats after massive ileocecal resection. Pediatr Res 2010; 68:183-7. [PMID: 20531250 DOI: 10.1203/pdr.0b013e3181eb2ee5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Long chain polyunsaturated fatty acids (LCPUFA)seem to be the most trophic macronutrients in inducing intestinal adaptation in adult short bowel syndrome (SBS), although their effects on intestinal adaptation in infants with SBS remain unknown.It is hypothesized that a high fat diet enriched with n-3 LCPUFA derived from fish oil (FO) will increase intestinal adaptation compared with a diet dominated by n-6 PUFA from corn oil (CO) in weanling SBS rats after massive ileocecal resection (ICR). Twenty-day-old rats were sorted into four groups, CO-sham, FO-sham,CO-ICR, and FO-ICR groups, and fed ad lib with the CO or FO diet, respectively, for 7 d after sham or ICR surgery. Compared with CO-ICR rats, FO-ICR rats consumed less diet per gram of weight gain, had less diarrhea and fecal fat excretion, and demonstrated a tendency toward better weight gain. The mucosal mass, DNA and RNA levels of the colon and RNA levels of the distal jejunum, and the colonic mucosal area (%) were significantly higher in FO-ICR rats than in CO-ICR rats. These results suggest that the beneficial effect of dietary FO is associated with better adaptation in the colon in weanling rats after ICR.
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Lightfoot JC, D'Agostino RB, Hamilton CA, Jordan J, Torti FM, Kock ND, Jordan J, Workman S, Hundley WG. Novel approach to early detection of doxorubicin cardiotoxicity by gadolinium-enhanced cardiovascular magnetic resonance imaging in an experimental model. Circ Cardiovasc Imaging 2010; 3:550-8. [PMID: 20622140 DOI: 10.1161/circimaging.109.918540] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND We sought to determine whether cardiovascular magnetic resonance measures of gadolinium (Gd) signal intensity (SI) within the left ventricular myocardium are associated with future changes in left ventricular ejection fraction (LVEF) after receipt of doxorubicin (DOX). METHODS AND RESULTS Forty Sprague-Dawley rats were divided into 3 groups scheduled to receive weekly intravenous doses of normal saline (n = 7), 1.5 mg/kg DOX (n = 19), or 2.5 mg/kg DOX (n = 14). Magnetic resonance determinations of LVEF and myocardial Gd-SI were performed before and at 2, 4, 7, and 10 weeks after DOX initiation. During treatment, animals were euthanized at different time points so that histopathologic assessments of the left ventricular myocardium could be obtained. Within-group analyses were performed to examine time-dependent relations between Gd-SI and primary events (deterioration in LVEF or an unanticipated death). Six of 19 animals receiving 1.5 mg/kg DOX and 10 of 14 animals receiving 2.5 mg/kg DOX experienced a primary event; no normal saline animals experienced a primary event. In animals with a primary event, histopathologic evidence of myocellular vacuolization occurred (P = 0.04), and the Gd-SI was elevated relative to baseline at the time of the event (P < 0.0001) and during the measurement period before the event (P = 0.0001). In all animals (including normal saline) without an event, measures of Gd-SI did not differ from baseline. CONCLUSIONS After DOX, low serial measures of Gd-SI predict an absence of an LVEF drop or unanticipated death. An increase in Gd-SI after DOX forecasts a subsequent drop in LVEF as well as histopathologic evidence of intracellular vacuolization consistent with DOX cardiotoxicity.
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Neal RE, Singh R, Hatcher HC, Kock ND, Torti SV, Davalos RV. Treatment of breast cancer through the application of irreversible electroporation using a novel minimally invasive single needle electrode. Breast Cancer Res Treat 2010; 123:295-301. [PMID: 20191380 DOI: 10.1007/s10549-010-0803-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/10/2010] [Indexed: 01/20/2023]
Abstract
Irreversible electroporation (IRE) is a therapeutic technology for the ablation of soft tissues using electrodes to deliver intense but short electric pulses across a cell membrane, creating nanopores that lead to cell death. This phenomenon only affects the cell membrane, leaving the extracellular matrix and sensitive structures intact, making it a promising technique for the treatment many types of tumors. In this paper, we present the first in vivo study to achieve tumor regression using a translatable, clinically relevant single needle electrode for treatment administration. Numerical models of the electric field distribution for the protocol used suggest that a 1000 V/cm field threshold is sufficient to treat a tumor, and that the electric field distribution will slightly decrease if the same protocol were used on a tumor deep seated within a human breast. Tumor regression was observed in 5 out of 7 MDA-MB231 human mammary tumors orthotopically implanted in female Nu/Nu mice, with continued growth in controls.
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Dance-Barnes ST, Kock ND, Moore JE, Lin EY, Mosley LJ, D'Agostino RB, McCoy TP, Townsend AJ, Miller MS. Lung tumor promotion by curcumin. Carcinogenesis 2009; 30:1016-23. [PMID: 19359593 DOI: 10.1093/carcin/bgp082] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Curcumin exhibits anti-inflammatory and antitumor activity and is being tested in clinical trials as a chemopreventive agent for colon cancer. Curcumin's chemopreventive activity was tested in a transgenic mouse model of lung cancer that expresses the human Ki-ras(G12C) allele in a doxycycline (DOX) inducible and lung-specific manner. The effects of curcumin were compared with the lung tumor promoter, butylated hydroxytoluene (BHT), and the lung cancer chemopreventive agent, sulindac. Treatment of DOX-induced mice with dietary curcumin increased tumor multiplicity (36.3 +/- 0.9 versus 24.3 +/- 0.2) and progression to later stage lesions, results which were similar to animals that were co-treated with DOX/BHT. Microscopic examination showed that the percentage of lung lesions that were adenomas and adenocarcinomas increased to 66% in DOX/BHT, 66% in DOX/curcumin and 49% in DOX/BHT/curcumin-treated groups relative to DOX only treated mice (19%). Immunohistochemical analysis also showed increased evidence of inflammation in DOX/BHT, DOX/curcumin and DOX/BHT/curcumin mice relative to DOX only treated mice. In contrast, co-treatment of DOX/BHT mice with 200 p.p.m. [DOSAGE ERROR CORRECTED] of sulindac inhibited the progression of lung lesions and reduced the inflammation. Lung tissue from DOX/curcumin-treated mice demonstrated a significant increase (33%; P = 0.01) in oxidative damage, as assessed by the levels of carbonyl protein formation, relative to DOX-treated control mice after 1 week on the curcumin diet. These results suggest that curcumin may exhibit organ-specific effects to enhance reactive oxygen species formation in the damaged lung epithelium of smokers and ex-smokers. Ongoing clinical trials thus may need to exclude smokers and ex-smokers in chemopreventive trials of curcumin.
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Muhammad FS, Goode AK, Kock ND, Arifin EA, Cline JM, Adams MR, Hoyer PB, Christian PJ, Isom S, Kaplan JR, Appt SE. Effects of 4-vinylcyclohexene diepoxide on peripubertal and adult Sprague-Dawley rats: ovarian, clinical, and pathologic outcomes. Comp Med 2009; 59:46-59. [PMID: 19295054 PMCID: PMC2703138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 07/22/2008] [Accepted: 10/05/2008] [Indexed: 05/27/2023]
Abstract
Young rats treated daily with intraperitoneal 4-vinylcyclohexene diepoxide (VCD) undergo selective destruction of primordial follicles, resulting in gradual ovarian failure resembling the menopausal transition in women. To determine whether VCD has similar effects on ovaries of older rats, adult and peripubertal Sprague-Dawley rats were injected intraperitoneally daily for 30 d with vehicle or VCD at 40 or 80 mg/kg. Body weight, food intake, complete blood counts, and markers of liver injury and renal function were measured during VCD treatment. Complete gross necropsy and microscopic observations were performed on day 31, and ovarian follicles were counted. At 80 mg/kg, VCD destroyed primordial and primary follicles to a similar extent in both adult and peripubertal animals, although adult rats likely started with fewer follicles and therefore approached follicle depletion. Treatment with VCD did not affect body weight, but food intake was reduced in both adult and peripubertal rats treated with 80 mg/kg VCD. Adult rats treated with 80 mg/kg VCD had neutrophilia and increased BUN and creatinine; in addition, 4 of these rats were euthanized on days 25 or 26 due to peritonitis. VCD treatment did not increase alanine aminotransferase levels, a marker of liver injury, although the 80-mg/kg dose increased liver weights. In conclusion, VCD effectively destroys small preantral follicles in adult Sprague-Dawley rats, making them a suitable model of the menopausal transition of women. However, because adult rats were more sensitive to the irritant properties of VCD, the use of a lower dose should be considered.
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Lightfoot JC, D'Agostino RB, Hamilton CA, Little WC, Torti FM, Kock ND, Robbins M, Hundley WG. Gadolinium enhanced magnetic resonance mean voxel signal intensity within the left ventricular myocardium changes prior to ejection fraction drop after receipt of cardiotoxic chemotherapy. J Cardiovasc Magn Reson 2009. [PMCID: PMC7852499 DOI: 10.1186/1532-429x-11-s1-p80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Scott LM, Xu X, Veenstra TD, Tooze JA, Wood CE, Register TC, Kock ND, Cline JM. Past oral contraceptive use and current dietary soy isoflavones influence estrogen metabolism in postmenopausal monkeys (Macaca fascicularis). Cancer Epidemiol Biomarkers Prev 2008; 17:2594-602. [PMID: 18843000 DOI: 10.1158/1055-9965.epi-08-0278] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Estrogen metabolism may play an important role in mammary carcinogenesis in postmenopausal women. We evaluated the effects of prior oral contraceptive (OC) treatment and current soy isoflavone consumption on endogenous estrogen metabolite concentration and biomarkers of tissue estrogen exposure in a monkey model. One hundred eighty-one female cynomolgus macaques were randomized to receive OC or placebo for 26 months premenopausally, then ovariectomized and randomized to one of three diets for 36 months: an isoflavone-depleted soy protein isolate (Soy-) diet, a diet containing soy protein isolate with a human equivalent of 129 mg isoflavone/d (Soy+), or a Soy- diet supplemented with conjugated equine estrogens (CEE+) at a human equivalent dose of 0.625 mg/d. Reverse-phase high-performance liquid chromatography directly coupled with tandem mass spectrometry was used to measure the concentrations of estrogen species in urine samples. Generally, prior OC treatment was associated with significantly reduced urinary estrogen metabolites (25-55% reduction; P<0.05 for each versus OC-). Animals that consumed isoflavones postmenopausally had increased urinary 2-hydroxyestrone and 16alpha-hydroxyestrone (50% and 56% increases, respectively), but reduced levels of 2-hydroxyestradiol, 2-methoxyestradiol, and 17-epiestriol (92%, 63%, and 66%, respectively), compared with animals fed a Soy- diet. Isoflavones did not have widespread effects on uterine or mammary proliferation biomarkers, whereas prior OC significantly reduced two of three proliferation end points in the endometrium. Premenopausal OCs may have long-term systemic effects on response to estrogen and its metabolism whereas postmenopausal dietary isoflavones may alter endogenous estrogen metabolism in a modest but selective manner.
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Pang B, Hong W, West-Barnette SL, Kock ND, Swords WE. Diminished ICAM-1 expression and impaired pulmonary clearance of nontypeable Haemophilus influenzae in a mouse model of chronic obstructive pulmonary disease/emphysema. Infect Immun 2008; 76:4959-67. [PMID: 18794286 PMCID: PMC2573371 DOI: 10.1128/iai.00664-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 07/02/2008] [Accepted: 09/03/2008] [Indexed: 11/20/2022] Open
Abstract
The airways of patients with chronic obstructive pulmonary disease (COPD) are continually colonized with bacterial opportunists like nontypeable Haemophilus influenzae (NTHi), and a wealth of evidence indicates that changes in bacterial populations within the lung can influence the severity of COPD. In this study, we used a murine model for COPD/emphysema to test the hypothesis that COPD affects pulmonary clearance. Mice were treated with a pulmonary bolus of elastase, and as reported previously, the lungs of these mice were pathologically similar to those with COPD/emphysema at approximately 1 month posttreatment. Pulmonary clearance of NTHi was significantly impaired in elastase-treated versus mock-treated mice. While histopathologic analysis revealed minimal differences in localized lung inflammation between the two groups, lower levels of intercellular adhesion molecule 1 (ICAM-1) were observed for the airway epithelial surface of elastase-treated mice than for those of control mice. Following infection, elastase-treated mice had lung pathology consistent with pneumonia for as long as 72 h postinfection, whereas at the same time point, mock-treated mice had cleared NTHi and showed little apparent pathology. Large aggregates of bacteria were observed within damaged lung tissue of the elastase-treated mice, whereas sparse individual bacteria were observed in lungs of mock-treated mice at the same time point postinfection. Additional infection studies showed that NTHi mutants with biofilm defects were less persistent in the elastase-treated mice than the parent strain. These findings establish a model for COPD-related infections and support the hypotheses that ICAM-1 promotes clearance of NTHi. Furthermore, the data indicate that NTHi may form biofilms within the context of COPD-related infections.
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Sikoski P, Trybus J, Cline JM, Muhammad FS, Eckhoff A, Tan J, Lockard M, Jolley T, Britt S, Kock ND. Cystic mammary adenocarcinoma associated with a prolactin-secreting pituitary adenoma in a New Zealand white rabbit (Oryctolagus cuniculus). Comp Med 2008; 58:297-300. [PMID: 18589874 PMCID: PMC2704120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 05/05/2008] [Indexed: 05/26/2023]
Abstract
Pituitary adenoma in a rabbitA 44-mo-old, female, nulliparous New Zealand White Rabbit (Oryctolagus cuniculus) presented with bilaterally diffusely enlarged mammary glands with enlarged, discolored teats that exuded brown, mucoid discharge. The complete blood count and serum chemistry panels were within normal limits, bacteria were not isolated from a culture of the discharge, and the clinical signs did not resolve with antibiotic treatment. Computed tomography and serum prolactin levels supported the diagnosis of mammary gland dysplasia, possibly due to a prolactin-secreting pituitary adenoma. Histologic evaluation confirmed the presence of a pituitary adenoma, mammary hyperplasia, dysplasia, and cystic mammary adenocarcinoma. Immunohistochemical staining confirmed the presence of abundant prolactin secreting cells in the pituitary adenoma. This is the second report of hyperprolactinemia with mammary dysplasia in rabbits, and the first report of cystic mammary adenocarcinoma associated with a prolactin-secreting pituitary adenoma in a rabbit.
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Capraro GA, Johnson JB, Kock ND, Parks GD. Virus growth and antibody responses following respiratory tract infection of ferrets and mice with WT and P/V mutants of the paramyxovirus Simian Virus 5. Virology 2008; 376:416-28. [PMID: 18456301 PMCID: PMC2574746 DOI: 10.1016/j.virol.2008.03.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 03/19/2008] [Accepted: 03/27/2008] [Indexed: 11/29/2022]
Abstract
P/V gene substitutions convert the non-cytopathic paramyxovirus Simian Virus 5 (SV5), which is a poor inducer of host cell responses in human tissue culture cells, into a mutant (P/V-CPI−) that induces high levels of apoptosis, interferon (IFN)-beta, and proinflammatory cytokines. However, the effect of SV5-P/V gene mutations on virus growth and adaptive immune responses in animals has not been determined. Here, we used two distinct animal model systems to test the hypothesis that SV5-P/V mutants which are more potent activators of innate responses in tissue culture will also elicit higher antiviral antibody responses. In mouse cells, in vitro studies identified a panel of SV5-P/V mutants that ranged in their ability to limit IFN responses. Intranasal infection of mice with these WT and P/V mutant viruses elicited equivalent anti-SV5 IgG responses at all doses tested, and viral titers recovered from the respiratory tract were indistinguishable. In primary cultures of ferret lung fibroblasts, WT rSV5 and P/V-CPI− viruses had phenotypes similar to those established in human cell lines, including differential induction of IFN secretion, IFN signaling and apoptosis. Intranasal infection of ferrets with a low dose of WT rSV5 elicited ~ 500 fold higher anti-SV5 serum IgG responses compared to the P/V-CPI− mutant, and this correlated with overall higher viral titers for the WT virus in tracheal tissues. There was a dose-dependent increase in antibody response to infection of ferrets with P/V-CPI−, but not with WT rSV5. Together our data indicate that WT rSV5 and P/V mutants can elicit distinct innate and adaptive immunity phenotypes in the ferret animal model system, but not in the mouse system. We present a model for the effect of P/V gene substitutions on SV5 growth and immune responses in vivo.
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Dance-Barnes ST, Kock ND, Floyd HS, Moore JE, Mosley LJ, D'Agostino RB, Pettenati MJ, Miller MS. Effects of mutant human Ki-ras(G12C) gene dosage on murine lung tumorigenesis and signaling to its downstream effectors. Toxicol Appl Pharmacol 2008; 231:77-84. [PMID: 18565564 DOI: 10.1016/j.taap.2008.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 04/08/2008] [Accepted: 04/18/2008] [Indexed: 11/16/2022]
Abstract
Studies in cell culture have suggested that the level of RAS expression can influence the transformation of cells and the signaling pathways stimulated by mutant RAS expression. However, the levels of RAS expression in vivo appear to be subject to feedback regulation, limiting the total amount of RAS protein that can be expressed. We utilized a bitransgenic mouse lung tumor model that expressed the human Ki-ras(G12C) allele in a tetracycline-inducible, lung-specific manner. Treatment for 12 months with 500 microg/ml of doxycycline (DOX) allowed for maximal expression of the human Ki-ras(G12C) allele in the lung, and resulted in the development of focal hyperplasia and adenomas. We determined if different levels of mutant RAS expression would influence the phenotype of the lung lesions. Treatment with 25, 100 and 500 microg/ml of DOX resulted in dose-dependent increases in transgene expression and tumor multiplicity. Microscopic analysis of the lungs of mice treated with the 25 microg/ml dose of DOX revealed infrequent foci of hyperplasia, whereas mice treated with the 100 and 500 microg/ml doses exhibited numerous hyperplastic foci and also adenomas. Immunohistochemical and RNA analysis of the downstream effector pathways demonstrated that different levels of mutant RAS transgene expression resulted in differences in the expression and/or phosphorylation of specific signaling molecules. Our results suggest that the molecular alterations driving tumorigenesis may differ at different levels of mutant Ki-ras(G12C) expression, and this should be taken into consideration when inducible transgene systems are utilized to promote tumorigenesis in mouse models.
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Bates JT, Honko AN, Graff AH, Kock ND, Mizel SB. Mucosal adjuvant activity of flagellin in aged mice. Mech Ageing Dev 2008; 129:271-81. [PMID: 18367233 DOI: 10.1016/j.mad.2008.01.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 12/11/2007] [Accepted: 01/25/2008] [Indexed: 01/22/2023]
Abstract
We evaluated the ability of flagellin, a highly effective mucosal adjuvant in mice and non-human primates, to promote mucosal innate and adaptive immunity in aged mice. We found that intratracheal instillation of flagellin induced a stronger respiratory innate response in aged mice than in young mice, and that intranasal instillation of flagellin was equally effective at triggering recruitment of T and B lymphocytes to the draining lymph nodes of young and aged mice. Intranasal immunization of aged mice with flagellin and the Yersinia pestis protein F1 promoted specific IgG and IgA production, but at lower levels and lower avidities than in young mice. Although intranasal instillation of flagellin and F1 antigen increased germinal center formation and size in young mice, it did not do so in aged mice. Our findings are consistent with the conclusion that flagellin can promote adaptive immune responses in aged mice, but at a less robust level than in young mice.
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Lally BE, Geiger GA, Kridel S, Arcury-Quandt AE, Robbins ME, Kock ND, Wheeler K, Peddi P, Georgakilas A, Kao GD, Koumenis C. Identification and biological evaluation of a novel and potent small molecule radiation sensitizer via an unbiased screen of a chemical library. Cancer Res 2007; 67:8791-9. [PMID: 17875720 PMCID: PMC3610568 DOI: 10.1158/0008-5472.can-07-0477] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
For patients with solid tumors, the tolerance of surrounding tissues often limits the dose of radiation that can be delivered. Thus, agents that preferentially increase the cytotoxic effects of radiation toward tumor cells would significantly alter the therapeutic ratio and improve patient survival. Using a high-throughput, unbiased screening approach, we have identified 4'-bromo-3'-nitropropiophenone (NS-123) as a radiosensitizer of human glioma cells in vitro and in vivo. NS-123 radiosensitized U251 glioma cells in a dose-dependent and time-dependent manner, with dose enhancement ratios ranging from 1.3 to 2.0. HT-29 colorectal carcinoma and A549 lung adenocarcinoma cells were also radiosensitized by NS-123 in vitro, whereas NS-123 did not increase the radiation sensitivity of normal human astrocytes or developmental abnormalities or lethality of irradiated Zebrafish embryos. In a novel xenograft model of U251 cells implanted into Zebrafish embryos, NS-123 enhanced the tumor growth-inhibitory effects of ionizing radiation (IR) with no apparent effect on embryo development. Similar results were obtained using a mouse tumor xenograft model in which NS-123 sensitized U251 tumors to IR while exhibiting no overt toxicity. In vitro pretreatment with NS-123 resulted in accumulation of unrepaired IR-induced DNA strand breaks and prolonged phosphorylation of the surrogate markers of DNA damage H2AX, ataxia telangiectasia mutated protein, DNA-dependent protein kinase, and CHK2 after IR, suggesting that NS-123 inhibits a critical step in the DNA repair pathway. These results show the potential of this cell-based, high-throughput screening method to identify novel radiosensitizers and suggest that NS-123 and similar nitrophenol compounds may be effective in antiglioma modalities.
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Nyamambi B, Ndlovu LR, Naik YS, Kock ND. Intestinal growth and function of broiler chicks fed sorghum based diets differing in condensed tannin levels. S AFR J ANIM SCI 2007. [DOI: 10.4314/sajas.v37i3.4092] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Jennings-Gee JE, Moore JE, Xu M, Dance ST, Kock ND, McCoy TP, Carr JJ, Miller MS. Strain-specific induction of murine lung tumors following in utero exposure to 3-methylcholanthrene. Mol Carcinog 2006; 45:676-84. [PMID: 16652375 DOI: 10.1002/mc.20215] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Fetal mice are more sensitive to chemical carcinogens than are adults. We previously demonstrated that resistant offspring of a DBA/2 x (C57BL/6 x DBA2) backcross exhibited a high incidence of lung tumors 12-13 mo after transplacental exposure to 3-methylcholanthrene (MC). We compared the effects of in utero treatment with MC on lung tumor incidence in the offspring of intermediately susceptible BALB/c (C), resistant C57BL/6 (B6), and reciprocal crosses between these strains. Pregnant mice were treated with 45 mg/kg of MC on day 17 of gestation and tumor incidence, multiplicity, and the Ki-ras mutational spectrum determined in the offspring 12-18 mo after birth. Tumor incidences in C mice and reciprocal crosses were 86% and 100%, respectively, while B6 mice demonstrated resistance to tumorigenesis, with a tumor incidence of 11%. Tumor multiplicities in C, B6C, CB6, and B6 mice were 3.3 +/- 3.2, 5.8 +/- 3.2, 5.0 +/- 2.7, and <0.1, respectively. Ki-ras mutations, which occurred chiefly in the K(s) allele (96%), were found in 79-81% of reciprocally crossed F1 mice, 64% of C mice, and 50% of B6 mice, with the Val(12), Asp(12), and Arg(13) mutations associated with more aggressive tumors. A subset of these mice was used to demonstrate the utility of computer tomography (CT) for the visualization and measurement of lung tumors in the submillimeter range in vivo. Based on known genetic differences in murine strains for lung cancer, our results suggest the presence of a previously unidentified genetic factor(s) which appears to specifically influence lung tumorigenesis following exposure to carcinogens during fetal development.
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Remick AK, Wood CE, Cann JA, Gee MK, Feiste EA, Kock ND, Cline JM. Histologic and immunohistochemical characterization of spontaneous pituitary adenomas in fourteen cynomolgus macaques (Macaca fascicularis). Vet Pathol 2006; 43:484-93. [PMID: 16846990 DOI: 10.1354/vp.43-4-484] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pituitary adenomas were identified in 14 of 491 (2.9%) cynomolgus macaques evaluated from 1994 to 2004. Cases included male (8) and female (6) cynomolgus macaques ranging from 18 to 32 years of age. Seven of the pituitary adenomas caused gross enlargement of the pituitary gland that was visible on postmortem examination, whereas the remaining 7 were multifocal microadenomas identified on histologic examination. A total of 35 adenomas were identified in the 14 macaques, 6 of which were being treated for diabetes mellitus. Mean (+/- SD) pituitary weight was 0.31 +/- 0.42 g, compared with 0.07 +/- 0.02 g for 430 historical control animals (P < 0.0001). Immunohistochemical staining for follicle-stimulating hormone, luteinizing hormone, prolactin, human growth hormone, thyroid-stimulating hormone, and adrenocorticotropic hormone was applied to pituitary tissue from all cases. Immunostaining revealed 22 of 35 (62.9%) lactotroph adenomas, 5 of 35 (14.3%) plurihormonal cell adenomas, 3 of 35 (8.6%) corticotroph adenomas, 2 of 35 (5.7%) null cell adenomas, 1 of 35 (2.9%) somatotroph adenomas, 1 of 35 (2.9%) mixed corticotroph-somatotroph adenomas, 1 of 35 (2.9%) mixed lactotroph-corticotroph adenomas, 0 of 35 gonadotroph adenomas, and 0 of 35 thyrotroph adenomas. This study represents the first extensive retrospective case series performed to evaluate the histologic and immunohistochemical characteristics of pituitary adenomas in cynomolgus macaques. Our findings indicated that macaque pituitary adenomas frequently had mixed histologic appearance and hormone expression, and that, similar to human pituitary adenomas, prolactin-secreting neoplasms were the most prevalent type.
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Floyd HS, Jennings-Gee JE, Kock ND, Miller MS. Genetic and epigenetic alterations in lung tumors from bitransgenic Ki-rasG12C expressing mice. Mol Carcinog 2006; 45:506-17. [PMID: 16482519 DOI: 10.1002/mc.20181] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mutations in Ki-ras occur in approximately 30-50% of patients with adenocarcinoma (AC) of the lung. We previously reported the development of a bitransgenic mouse model that expressed the human Ki-ras(G12C) allele in a lung-specific, tetracycline-inducible manner and gave rise to benign lung tumors. In the current study, these benign tumors, which represent relatively early lesions in neoplastic progression, were analyzed for molecular alterations secondary to mutant Ki-ras expression to determine the gene(s) that contribute to adenoma (AD) development. Tumors were removed following doxycycline (DOX) treatment for 9 and 12 mo and examined for alterations in cell-cycle regulatory genes. Quantification of mRNA expression for cyclin D1, retinoblastoma, p16(Ink4a), p19(Arf), and survivin was carried out by real-time PCR. All of the tumors examined exhibited a mean reduction of approximately fivefold for the retinoblastoma gene (P < 0.02). Increased expression of both p19(Arf) and survivin were detected in a majority of the tumors examined (P < 0.01 and 0.001, respectively), but no change in cyclin D1 RNA expression was observed. A subset of the lung tumors (8/28) displayed reduced levels of p16(Ink4a) expression (P = 0.02). Immunohistochemical analysis confirmed the upregulation of p19(Arf) and survivin in all 10 of the lung tumors examined. However, increased staining for cyclin D1 was observed in the tumor tissue. In addition, increased levels of activated p53 were found in lung tumor tissues stained with an anti-phospho-p53 antibody, while an absence of staining was observed with an anti-phospho-pRb antibody in both normal control and tumor tissue. Analysis of the methylation status of p16(Ink4a) by methylation-specific PCR (MSP) demonstrated that seven of eight tumors exhibiting decreased expression of p16(Ink4a) had at least partial methylation of the promoter region. Single stranded conformational polymorphism (SSCP) analysis demonstrated that neither exons 1 or 2 of p16(Ink4a) nor exons 5-8 of p53 exhibited mutations. These data thus identify alterations in specific genes and pathways that combine with the mutation in Ki-ras to promote the formation of benign lung tumors and suggest potential targets for the development of novel chemotherapeutic and chemopreventive agents during the early stages of lung tumor progression.
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Wilkinson J, Di X, Schönig K, Buss JL, Kock ND, Cline JM, Saunders TL, Bujard H, Torti SV, Torti FM. Tissue-specific expression of ferritin H regulates cellular iron homoeostasis in vivo. Biochem J 2006; 395:501-7. [PMID: 16448386 PMCID: PMC1462685 DOI: 10.1042/bj20060063] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ferritin is a ubiquitously distributed iron-binding protein. Cell culture studies have demonstrated that ferritin plays a role in maintenance of iron homoeostasis and in the protection against cytokine- and oxidant-induced stress. To test whether FerH (ferritin H) can regulate tissue iron homoeostasis in vivo, we prepared transgenic mice that conditionally express FerH and EGFP (enhanced green fluorescent protein) from a bicistronic tetracycline-inducible promoter. Two transgenic models were explored. In the first, the FerH and EGFP transgenes were controlled by the tTA(CMV) (Tet-OFF) (where tTA and CMV are tet transactivator protein and cytomegalovirus respectively). In skeletal muscle of mice bearing the FerH/EGFP and tTA(CMV) transgenes, FerH expression was increased 6.0+/-1.1-fold (mean+/-S.D.) compared with controls. In the second model, the FerH/EGFP transgenes were controlled by an optimized Tet-ON transactivator, rtTA2(S)-S2(LAP) (where rtTA is reverse tTA and LAP is liver activator protein), resulting in expression predominantly in the kidney and liver. In mice expressing these transgenes, doxycycline induced FerH in the kidney by 14.2+/-4.8-fold (mean+/-S.D.). Notably, increases in ferritin in overexpressers versus control littermates were accompanied by an elevation of IRP (iron regulatory protein) activity of 2.3+/-0.9-fold (mean+/-S.D.), concurrent with a 4.5+/-2.1-fold (mean+/-S.D.) increase in transferrin receptor, indicating that overexpression of FerH is sufficient to elicit a phenotype of iron depletion. These results demonstrate that FerH not only responds to changes in tissue iron (its classic role), but can actively regulate overall tissue iron balance.
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Floyd HS, Farnsworth CL, Kock ND, Mizesko MC, Little JL, Dance ST, Everitt J, Tichelaar J, Whitsett JA, Miller MS. Conditional expression of the mutant Ki-rasG12C allele results in formation of benign lung adenomas: development of a novel mouse lung tumor model. Carcinogenesis 2005; 26:2196-206. [PMID: 16051643 PMCID: PMC1351110 DOI: 10.1093/carcin/bgi190] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
To determine the effects of expression of mutant Ki-ras on lung tumorigenesis, we developed a bitransgenic mouse model that expresses the human Ki-ras(G12C) allele in alveolar type II and/or Clara cells in a tetracycline-inducible, lung-specific manner. Expression of Ki-ras(G12C) caused multiple, small lung tumors over a 12-month time period. Although tumor multiplicity increased upon continued Ki-ras expression, most lung lesions were hyperplasias or well-differentiated adenomas. This is in contrast to the more severe phenotypes observed in other transgenic mouse models in which different mutant Ki-ras alleles were expressed in the lung. Expression of Ki-ras(G12C) was associated with a 2-fold increase in the activation of the Ras and Ral signaling pathways and increased phosphorylation of Ras downstream effectors, including Erk, p90 ribosomal S6 kinase, ribosomal S6 protein, p38 and MAPKAPK-2. In contrast, expression of the transgene had no effect on the activation of the JNK and Akt signaling pathways. Withdrawal of doxycycline for 1 month resulted in almost a complete absence of proliferative pulmonary lesions, suggesting tumor regression in the absence of Ki-ras expression. Mutant Ki-ras(G12C) expression was sufficient for initial lung tumor transformation, required for maintenance of tumor phenotype, and induced transformation of lung epithelial cells by the activation of multiple effector pathways. These results describe a novel mouse lung tumor model demonstrating benign tumor development in the absence of tumor progression, which will provide a new tool for understanding the early stages of lung tumor pathogenesis.
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Wood CE, Register TC, Anthony MS, Kock ND, Cline JM. Breast and uterine effects of soy isoflavones and conjugated equine estrogens in postmenopausal female monkeys. J Clin Endocrinol Metab 2004; 89:3462-8. [PMID: 15240632 DOI: 10.1210/jc.2003-032067] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
In this study we evaluated the long-term effects of soy isoflavones on intermediate markers of cancer risk in the normal postmenopausal monkey breast and uterus. Ovariectomized female cynomolgus monkeys were randomized to receive one of three diets for 36 months: 1) isoflavone-depleted soy protein isolate (SPI-) (n = 57); 2) soy protein isolate with the equivalent of 129 mg/d isoflavones (SPI+) (n = 60); or 3) isoflavone-depleted soy protein isolate with conjugated equine estrogens at a dose scaled to approximate 0.625 mg/d in women (n = 62). End points included breast and uterine proliferation markers, sex steroid receptor expression, and serum estrogens. Epithelial proliferation and progesterone receptor expression in the breast and uterus were significantly higher in the conjugated equine estrogen group, compared with SPI+ and SPI- groups, whereas no significant differences were detected between the SPI+ and SPI- groups. SPI+ treatment resulted in significantly lower serum concentrations of estrone (P < 0.01) and estradiol (P < 0.05) vs. SPI-. Within the SPI+ group, serum isoflavone concentrations were inversely correlated with serum estrone and mammary glandular area. These findings suggest that high dietary levels of soy isoflavones do not stimulate breast or uterine proliferation in postmenopausal monkeys and may contribute to an estrogen profile associated with reduced breast cancer risk.
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Kock ND, Kock RA, Wambua E, Mohan K. Listeriosis in a free-ranging colobus monkey (Colobus guereza caudatus) in Kenya. Vet Rec 2003; 152:141-2. [PMID: 12585602 DOI: 10.1136/vr.152.5.141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Kock ND, Kampamba G, Mukaratirwa S, du Toit J. Disease investigation into free-ranging Kafue lechwe (Kobus leche kafuensis) on the Kafue Flats in Zambia. Vet Rec 2002; 151:482-4. [PMID: 12418533 DOI: 10.1136/vr.151.16.482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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