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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Health-Related Quality of Life After Stereotactic Body Radiation Therapy for Localized Prostate Cancer: Results From a Multi-institutional Consortium of Prospective Trials

Purpose: To evaluate the early and late health-related quality of life (QOL) outcomes among prostate cancer patients following stereotactic body radiation therapy (SBRT). Methods and Materials: Patient self-reported QOL was prospectively measured among 864 patients from phase 2 clinical trials of SBRT for localized prostate cancer. Data from the Expanded Prostate Cancer Index Composite (EPIC) instrument were obtained at baseline and at regular intervals up to 6 years. SBRT delivered a median dose of 36.25 Gy in 4 or 5 fractions. A short course of androgen deprivation therapy was given to 14% of patients. Results: Median follow-up was 3 years and 194 patients remained evaluable at 5 years. A transient decline in the urinary and bowel domains was observed within the first 3 months after SBRT which returned to baseline status or better within 6 months and remained so beyond 5 years. The same pattern was observed among patients with good versus poor baseline function and was independent of the degree of early toxicities. Sexual QOL decline was predominantly observed within the first 9 months, a pattern not altered by the use of androgen deprivation therapy or patient age. Conclusion: Long-term outcome demonstrates that prostate SBRT is well tolerated and has little lasting impact on health-related QOL. A transient and modest decline in urinary and bowel QOL during the first few months after SBRT quickly recovers to baseline levels. With a large number of patients evaluable up to 5 years following SBRT, it is unlikely that unexpected late adverse effects will manifest themselves.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Arecoline augments cellular proliferation in the prostate gland of male Wistar rats

Areca nut chewing is the fourth most popular habit in the world due to its effects as a mild stimulant, causing a feeling of euphoria and slightly heightened alertness. Areca nuts contain several alkaloids and tannins, of which arecoline is the most abundant and known to have several adverse effects in humans, specially an increased risk of oral cancer. On evaluating the effects of arecoline on the male endocrine physiology in Wistar rats, it was found that arecoline treatment led to an overall enlargement and increase in the wet weight of the prostate gland, and a two-fold increase in serum gonadotropin and testosterone levels. Since the prostate is a major target for testosterone, the consequences of arecoline consumption were studied specifically in the prostate gland. Arecoline treatment led to an increase in the number of rough endoplasmic reticulum and reduction of secretory vesicles, signifying a hyperactive state of the prostate. Increased expression of androgen receptors in response to arecoline allowed for enhanced effect of testosterone in the prostate of treated animals, which augmented cell proliferation, subsequently confirmed by an increase in the expression of Ki-67 protein. Cellular proliferation was also the outcome of concomitant over expression of the G{sub 1}-to-S cell cycle regulatory proteins, cyclin D1 and CDK4, both at the transcriptional and translational levels. Taken together, the findings provide the first evidence that regular use of arecoline may lead to prostatic hyperplasia and hypertrophy, and eventually to disorders associated with prostate enlargement. - Highlights: > Effect of arecoline was investigated on the endocrine physiology of male Wistar rats. > Increase observed in prostate size, wet weight, serum testosterone and gonadotropins. > Arecoline increased RER, expression of androgen receptor and cellular proliferation. > Upregulation of cyclin D1 and CDK4 seen at transcriptional and translational levels. > It may cause disorders associated with prostatic hyperplasia and hyperactivity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Antiandrogenic activity of phthalate mixtures: Validity of concentration addition

Phthalates and bisphenol A have very widespread use leading to significant exposure of humans. They are suspected to interfere with the endocrine system, including the androgen, estrogen and the thyroid hormone system. Here we analyzed the antiandrogenic activity of six binary, and one ternary mixture of phthalates exhibiting complete antiandrogenic dose–response curves, and binary mixtures of phthalates and bisphenol A at equi-effective concentrations of EC{sub 10}, EC{sub 25} and EC{sub 50} in MDA-kb2 cells. Mixture activity followed the concentration addition (CA) model with a tendency to synergism at high and antagonism at low concentrations. Isoboles and the toxic unit approach (TUA) confirmed the additive to synergistic activity of the binary mixtures BBP + DBP, DBP + DEP and DEP + BPA at high concentrations. Both methods indicate a tendency to antagonism for the EC{sub 10} mixtures BBP + DBP, BBP + DEP and DBP + DEP, and the EC{sub 25} mixture of DBP + BPA. A ternary mixture revealed synergism at the EC{sub 50}, and weak antagonistic activity at the EC{sub 25} level by the TUA. A mixture of five phthalates representing a human urine composition and reflecting exposure to corresponding parent compounds showed no antiandrogenic activity. Our study demonstrates that CA is an appropriate concept to account for mixture effects of antiandrogenic phthalates and bisphenol A. The interaction indicates a departure from additivity to antagonism at low concentrations, probably due to interaction with the androgen receptor and/or cofactors. This study emphasizes that a risk assessment of phthalates should account for mixture effects by applying the CA concept. -- Highlights: ► Antiandrogenic activity of mixtures of 2 and 3 phthalates are assessed in MDA-kb2 cells. ► Mixture activities followed the concentration addition model. ► A tendency to synergism at high and antagonism at low levels occurred.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Unexpected gender difference in sensitivity to the acute toxicity of dioxin in mice

The acute toxicity of the ubiquitous environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) varies widely among species and strains. Previous studies in rats have established that females are approximately 2-fold more sensitive to TCDD lethality than males. However, there is a surprising gap in the literature regarding possible gender-related sensitivity differences in mice. In the present study, by using three substrains of TCDD-sensitive C57BL/6 mice and transgenic mice on this background, we demonstrated that: 1) in contrast to the situation in rats, female mice are the more resistant gender; 2) the magnitude of the divergence between male and female mice depends on the substrain, but can amount to over 10-fold; 3) AH receptor protein expression levels or mutations in the primary structure of this receptor are not involved in the resistance of female mice of a C57BL/6 substrain, despite their acute LD{sub 50} for TCDD being over 5000 μg/kg; 4) transgenic mice that globally express the rat wildtype AH receptor follow the mouse type of gender difference; 5) in gonadectomized mice, ovarian estrogens appear to enhance TCDD resistance, whereas testicular androgens seem to augment TCDD susceptibility; and 6) the gender difference correlates best with the severity of liver damage, which is also reflected in hepatic histopathology and the expression of pro-inflammatory cytokines, especially IL-6. Hence, the two closely related rodent species most often employed in toxicological risk characterization studies, rat and mouse, represent opposite examples of the influence of gender on dioxin sensitivity, further complicating the risk assessment of halogenated aromatic hydrocarbons. -- Highlights: ► In contrast to rats, male mice are more sensitive to TCDD toxicity than female mice. ► The resistance of female C57BL/6Kuo mice matches or exceeds that of male DBA/2 mice. ► The resistance of female C57BL/6Kuo mice is not based on AHR structure or abundance. ► Both androgens and estrogens appear to influence TCDD sensitivity. ► TCDD sensitivity correlates best with the severity of lesions in the liver.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

3,3′-Diindolylmethane, but not indole-3-carbinol, inhibits histone deacetylase activity in prostate cancer cells

Increased consumption of cruciferous vegetables is associated with a reduced risk of developing prostate cancer. Indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM) are phytochemicals derived from cruciferous vegetables that have shown promise in inhibiting prostate cancer in experimental models. Histone deacetylase (HDAC) inhibition is an emerging target for cancer prevention and therapy. We sought to examine the effects of I3C and DIM on HDACs in human prostate cancer cell lines: androgen insensitive PC-3 cells and androgen sensitive LNCaP cells. I3C modestly inhibited HDAC activity in LNCaP cells by 25% but no inhibition of HDAC activity was detected in PC-3 cells. In contrast, DIM significantly inhibited HDAC activity in both cell lines by as much as 66%. Decreases in HDAC activity correlated with increased expression of p21, a known target of HDAC inhibitors. DIM treatment caused a significant decrease in the expression of HDAC2 protein in both cancer cell lines but no significant change in the protein levels of HDAC1, HDAC3, HDAC4, HDAC6 or HDAC8 was detected. Taken together, these results show that inhibition of HDAC activity by DIM may contribute to the phytochemicals' anti-proliferative effects in the prostate. The ability of DIM to target aberrant epigenetic patterns, in addition to its effects on detoxification of carcinogens, may make it an effective chemopreventive agent by targeting multiple stages of prostate carcinogenesis. -- Highlights: ► DIM inhibits HDAC activity and decreases HDAC2 expression in prostate cancer cells. ► DIM is significantly more effective than I3C at inhibiting HDAC activity. ► I3C has no effect on HDAC protein expression. ► Inhibition of HDAC activity by DIM is associated with increased p21 expression. ► HDAC inhibition may be a novel epigenetic mechanism for cancer prevention with DIM.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Atrazine acts as an endocrine disrupter by inhibiting cAMP-specific phosphodiesterase-4

Atrazine, one of the most commonly used herbicides worldwide, acts as an endocrine disruptor, but the mechanism of its action has not been characterized. In this study, we show that atrazine rapidly increases cAMP levels in cultured rat pituitary and testicular Leydig cells in a concentration-dependent manner, but less effectively than 3-isobutyl-1-methylxanthine, a competitive non-specific inhibitor of phosphodiesterases (PDEs). In forskolin (an activator of adenylyl cyclase)- and probenecid (an inhibitor of cyclic nucleotide transporters)-treated cells, but not in 3-isobutyl-1-methylxanthine-treated cells, atrazine further increased cAMP levels, indicating that inhibition of PDEs accounts for accumulation of cAMP. In contrast to cAMP, atrazine did not alter cGMP levels, further indicating that it inhibits cAMP-specific PDEs. Atrazine-induced changes in cAMP levels were sufficient to stimulate prolactin release in pituitary cells and androgen production in Leydig cells, indicating that it acts as an endocrine disrupter both in cells that secrete by exocytosis of prestored hormones and in cells that secrete by de novo hormone synthesis. Rolipram abolished the stimulatory effect of atrazine on cAMP release in both cell types, suggesting that it acts as an inhibitor of PDE4s, isoforms whose mRNA transcripts dominate in pituitary and Leydig cells together with mRNA for PDE8A. In contrast, immortalized lacto-somatotrophs showed low expression of these mRNA transcripts and several fold higher cAMP levels compared to normal pituitary cells, and atrazine was unable to further increase cAMP levels. These results indicate that atrazine acts as a general endocrine disrupter by inhibiting cAMP-specific PDE4s. -- Highlights: ► Atrazine stimulates cAMP accumulation in pituitary and Leydig cells. ► Atrazine also stimulates PRL and androgens secretion. ► Stimulatory effects of atrazine were abolished in cells with IBMX-inhibited PDEs. ► Atrazine specificity toward cAMP-specific PDEs was indicated by no changes in cGMP. ► Rolipram, a specific PDE4 inhibitor, also prevents stimulatory effects of atrazine. ► Atrazine acts as an endocrine disrupter by inhibiting cAMP-specific PDE4.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Currently used pesticides and their mixtures affect the function of sex hormone receptors and aromatase enzyme activity

The endocrine-disrupting potential of pesticides is of health concern, since they are found ubiquitously in the environment and in food items. We investigated in vitro effects on estrogen receptor (ER) and androgen receptor (AR) transactivity, and aromatase enzyme activity, of the following pesticides: 2-methyl-4-chlorophenoxyacetic acid (MCPA), terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb, cypermethrin, tau fluvalinate, malathion and the metabolite ethylene thiourea (ETU). The pesticides were analyzed alone and in selected mixtures. Effects of the pesticides on ER and AR function were assessed in human breast carcinoma MVLN cells and hamster ovary CHO-K1 cells, respectively, using luciferase reporter gene assays. Effects on aromatase enzyme activity were analyzed in human choriocarcinoma JEG-3 cells, employing the classical [{sup 3}H]{sub 2}O method. Five pesticides (terbuthylazine, propiconazole, prothioconazole, cypermethrin and malathion) weakly induced the ER transactivity, and three pesticides (bitertanol, propiconazole and mancozeb) antagonized the AR activity in a concentration-dependent manner. Three pesticides (terbuthylazine, propiconazole and prothioconazole) weakly induced the aromatase activity. In addition, two mixtures, consisting of three pesticides (bitertanol, propiconazole, cypermethrin) and five pesticides (terbuthylazine, bitertanol, propiconazole, cypermethrin, malathion), respectively, induced the ER transactivity and aromatase activity, and additively antagonized the AR transactivity. In conclusion, our data suggest that currently used pesticides possess endocrine-disrupting potential in vitro which can be mediated via ER, AR and aromatase activities. The observed mixture effects emphasize the importance of considering the combined action of pesticides in order to assure proper estimations of related health effect risks. - Highlights: • Currently used pesticides possess endocrine-disrupting (ED) potential in vitro. • ED effects can be mediated via sex hormone receptors and/or the aromatase enzyme. • Additive mixture effects on androgen receptor transactivity were observed.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Designed modulation of sex steroid signaling inhibits telomerase activity and proliferation of human prostate cancer cells

The predominant estrogen-receptor (ER)-β signaling in normal prostate is countered by increased ER-α signaling in prostate cancer (CaP), which in association with androgen-receptor (AR) signaling results in pathogenesis of the disease. However CaP treatments mostly target AR signaling which is initially effective but eventually leads to androgen resistance, hence simultaneous targeting of ERs has been proposed. A novel series of molecules were designed with multiple sex-steroid receptor modulating capabilities by coalescing the pharmacophores of known anti-CaP molecules that act via modulation of ER(α/β) and/or AR, viz. 3,3′diindolylmethane (DIM), mifepristone, toremifene, tamoxifen and raloxifene. N,N-diethyl-4-((2-(4-methoxyphenyl)-1H-indol-3-yl)methyl) aniline (DIMA) was identified as the most promising structure of this new series. DIMA increased annexin-V labelling, cell-cycle arrest and caspase-3 activity, and decreased expression of AR and prostate specific antigen in LNCaP cells, in vitro. Concurrently, DIMA increased ER-β, p21 and p27 protein levels in LNCaP cells and exhibited ∼ 5 times more selective binding for ER-β than ER-α, in comparison to raloxifene. DIMA exhibited a dose-dependent ER-β agonism and ER-α antagonism in classical gene reporter assay and decreased hTERT (catalytic subunit of telomerase) transcript levels in LNCaP at 3.0 μM (P < 0.05). DIMA also dose-dependently decreased telomerase enzyme activity in prostate cancer cells. It is thus concluded that DIMA acts as a multi-steroid receptor modulator and effectively inhibits proliferation of prostate cancer cells through ER-β mediated telomerase inhibition, by countering actions of ER-α and AR. Its unique molecular design can serve as a lead structure for generation of potent agents against endocrine malignancies like the CaP.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Metabolism of UV-filter benzophenone-3 by rat and human liver microsomes and its effect on endocrine-disrupting activity

Benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) is widely used as sunscreen for protection of human skin and hair from damage by ultraviolet (UV) radiation. In this study, we examined the metabolism of BP-3 by rat and human liver microsomes, and the estrogenic and anti-androgenic activities of the metabolites. When BP-3 was incubated with rat liver microsomes in the presence of NADPH, 2,4,5-trihydroxybenzophenone (2,4,5-triOH BP) and 3-hydroxylated BP-3 (3-OH BP-3) were newly identified as metabolites, together with previously detected metabolites 5-hydroxylated BP-3 (5-OH BP-3), a 4-desmethylated metabolite (2,4-diOH BP) and 2,3,4-trihydroxybenzophenone (2,3,4-triOH BP). In studies with recombinant rat cytochrome P450, 3-OH BP-3 and 2,4,5-triOH BP were mainly formed by CYP1A1. BP-3 was also metabolized by human liver microsomes and CYP isoforms. In estrogen reporter (ER) assays using estrogen-responsive CHO cells, 2,4-diOH BP exhibited stronger estrogenic activity, 2,3,4-triOH BP exhibited similar activity, and 5-OH BP-3, 2,4,5-triOH BP and 3-OH BP-3 showed lower activity as compared to BP-3. Structural requirements for activity were investigated in a series of 14 BP-3 derivatives. When BP-3 was incubated with liver microsomes from untreated rats or phenobarbital-, 3-methylcholanthrene-, or acetone-treated rats in the presence of NADPH, estrogenic activity was increased. However, liver microsomes from dexamethasone-treated rats showed decreased estrogenic activity due to formation of inactive 5-OH BP-3 and reduced formation of active 2,4-diOH BP. Anti-androgenic activity of BP-3 was decreased after incubation with liver microsomes. - Highlights: • Metabolic modification of the endocrine-disrupting activity of BP-3 was examined. • 2,4,5-TriOH BP and 3-OH BP-3 were identified as new BP-3 metabolites. • 2,4-DiOH BP and 2,3,4-triOH BP exhibited high or similar estrogenic activities. • Estrogenic activity of BP-3 was enhanced by incubation with rat liver microsomes. • Structural requirements for the activities of BP-3 derivatives were demonstrated.

3-METHYLCHOLANTHRENE↗
DOE OSTI2017

The scaffold protein RACK1 is a target of endocrine disrupting chemicals (EDCs) with important implication in immunity

We recently demonstrated the existence of a complex hormonal balance between steroid hormones in the control of RACK1 (Receptor for Activated C Kinase 1) expression and immune activation, suggesting that this scaffold protein may also be targeted by endocrine disrupting chemicals (EDCs). As a proof of concept, we investigated the effect of the doping agent nandrolone, an androgen receptor (AR) agonist, and of p,p′DDT (dichlorodiphenyltrichloroethane) and its main metabolite p,p′DDE (dichlorodiphenyldichloroethylene), a weak and strong AR antagonist, respectively, on RACK1 expression and innate immune response. In analogy to endogenous androgens, nandrolone induced a dose-related increase in RACK1 transcriptional activity and protein expression, resulting in increased LPS-induced IL-8 and TNF-α production and proliferation in THP-1 cells. Conversely, p,p′DDT and p,p′DDE significantly decrease RACK1 expression, LPS-induced cytokine production and CD86 expression; with p,p′DDE exerting a stronger repressor effect than p,p′DDT, consistent with its stronger AR antagonistic effect. These results indicate that RACK1 could be a relevant target of EDCs, responding in opposite ways to agonist or antagonist of AR, representing a bridge between the endocrine system and the innate immune system. - Highlights: • RACK1 expression can be induced by AR agonists with a consequent enhancement of the response to LPS. • RACK1 can be negatively modulated by the AR antagonists DDT and its main metabolite p,p′DDE. • RACK1 can be a relevant target of EDCs, representing a bridge between the endocrine system and the immune system.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Active site proton delivery and the lyase activity of human CYP17A1

Highlights: •The disruption of PREG/PROG hydroxylation activity by T306A showed the participation of Cpd I. •T306A supports the involvement of a nucleophilic peroxo-anion during lyase activity. •The presence of cytochrome b{sub 5} augments C–C lyase activity. •Δ5-Steroids are preferred substrates for CYP17 catalysis. -- Abstract: Cytochrome P450 CYP17A1 catalyzes a series of reactions that lie at the intersection of corticoid and androgen biosynthesis and thus occupies an essential role in steroid hormone metabolism. This multifunctional enzyme catalyzes the 17α-hydroxylation of Δ4- and Δ5-steroids progesterone and pregnenolone to form the corresponding 17α-hydroxy products through its hydroxylase activity, and a subsequent 17,20-carbon–carbon scission of pregnene-side chain produce the androgens androstenedione (AD) and dehydroepiandrosterone (DHEA). While the former hydroxylation reaction is believed to proceed through a conventional “Compound I” rebound mechanism, it has been suggested that the latter carbon cleavage is initiated by an iron-peroxy intermediate. We report on the role of Thr306 in CYP17 catalysis. Thr306 is a member of the conserved acid/alcohol pair thought to be essential for the efficient delivery of protons required for hydroperoxoanion heterolysis and formation of Compound I in the cytochromes P450. Wild type and T306A CYP17A1 self-assembled in Nanodiscs were used to quantitate turnover and coupling efficiencies of CYP17’s physiological Δ4- and Δ5-substrates. We observed that T306A co-incorporated in Nanodiscs with its redox partner cytochrome P450 oxidoreductase, coupled NADPH only by 0.9% and 0.7% compared to the wild type (97% and 22%) during the conversion of pregnenolone and progesterone, respectively, to the corresponding 17-OH products. Despite increased oxidation of pyridine nucleotide, hydroxylase activity was drastically diminished in the T306A mutant, suggesting a high degree of uncoupling in which reducing equivalents and protons are funneled into non-productive pathways. This is similar to previous work with other P450 catalyzed hydroxylation. However, catalysis of carbon–carbon bond scission by the T306A mutant was largely unimpeded by disruption of the CYP17A1 acid-alcohol pair. The unique response of CYP17A1 lyase activity to mutation of Thr306 is consistent with a reactive intermediate formed independently of proton delivery in the active site, and supports involvement of a nucleophilic peroxo-anion rather than the traditional Compound I in catalysis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2010

Hypofractionated Boost to the Dominant Tumor Region With Intensity Modulated Stereotactic Radiotherapy for Prostate Cancer: A Sequential Dose Escalation Pilot Study

Purpose: To evaluate the feasibility, tolerability, and preliminary outcomes in patients with prostate cancer treated according to a hypofractionated dose escalation protocol to boost the dominant tumor-bearing region of the prostate. Methods and Materials: After conventional fractionated external radiotherapy to 64 to 64.4Gy, 50 patients with nonmetastatic prostate cancer were treated with an intensity-modulated radiotherapy hypofractionated boost under stereotactic conditions to a reduced prostate volume to the dominant tumor region. A rectal balloon inflated with 60cc of air was used for internal organ immobilization. Five, 8, and 8 patients were sequentially treated with two fractions of 5, 6, or 7Gy, respectively (normalized total dose in 2Gy/fraction [NTD{sub 2Gy}] < 100Gy, low-dose group), whereas 29 patients received two fractions of 8Gy each (NTD{sub 2Gy} > 100Gy, high-dose group). Androgen deprivation was given to 33 patients. Acute and late toxicities were assessed according to the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer (RTOG/EORTC) scoring system. Results: Two patients presented with Grade 3 acute urinary toxicity. The 5-year probabilities of {>=}Grade 2 late urinary and late low gastrointestinal (GI) toxicity-free survival were 82.2% {+-} 7.4% and 72.2% {+-} 7.6%, respectively. The incidence and severity of acute or late toxicities were not correlated with low- vs. high-dose groups, pelvic irradiation, age, or treatment with or without androgen deprivation. The 5-year biochemical disease-free survival (b-DFS) and disease-specific survival were 98% {+-} 1.9% and 100%, respectively. Conclusion: Intensity-modulated radiotherapy hypofractionated boost dose escalation under stereotactic conditions was feasible, and showed excellent outcomes with acceptable long-term toxicity. This approach may well be considered an alternative to high-dose-rate brachytherapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Adenovirus E2F1 Overexpression Sensitizes LNCaP and PC3 Prostate Tumor Cells to Radiation In Vivo

Purpose: We previously showed that E2F1 overexpression radiosensitizes prostate cancer cells in vitro. Here, we demonstrate the radiosensitization efficacy of adenovirus (Ad)-E2F1 infection in growing (orthotopic) LNCaP and (subcutaneous) PC3 nude mice xenograft tumors. Methods and Materials: Ad-E2F1 was injected intratumorally in LNCaP (3 x 10{sup 8} plaque-forming units [PFU]) and PC3 (5 x 10{sup 8} PFU) tumors treated with or without radiation. LNCaP tumor volumes (TV) were measured by magnetic resonance imaging, caliper were used to measure PC3 tumors, and serum prostate-specific antigen (PSA) levels were determined by enzyme-linked immunosorbent assay. Apoptosis was measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling, and key proteins involved in cell death signaling were analyzed by Western blotting. Results: Intracellular overexpression of Ad-E2F1 had a significant effect on the regression of TV and reduction of PSA levels relative to that of adenoviral luciferase (Ad-Luc)-infected control. The in vivo regressing effect of Ad-E2F1 on LNCaP tumor growth was significant (PSA, 34 ng/ml; TV, 142 mm{sup 3}) compared to that of Ad-Luc control (PSA, 59 ng/ml; TV, 218 mm{sup 3}; p <0.05). This effect was significantly enhanced by radiation therapy (compare: Ad-E2F1+RT/PSA, 16 ng/ml, and TV, 55 mm{sup 3} to Ad-Luc+RT/PSA, 42 ng/ml, and TV, 174 mm{sup 3}, respectively; p <0.05). For PC3 tumors, the greatest effect was observed with Ad-E2F1 infection alone; there was little or no effect when radiotherapy (RT) was combined. However, addition of RT enhanced the level of in situ apoptosis in PC3 tumors. Molecularly, addition of Ad-E2F1 in a combination treatment abrogated radiation-induced BCL-2 protein expression and was associated with an increase in activated BAX, and together they caused a potent radiosensitizing effect, irrespective of p53 and androgen receptor functional status. Conclusions: We show here for the first time that ectopic overexpression of E2F1 in vivo, using an adenoviral vector, significantly inhibits orthotopic p53 wild-type LNCaP tumors and subcutaneous p53-null PC3 tumors in nude mice. Furthermore, we demonstrate that E2F1 strongly sensitizes LNCaP tumors to RT. These findings suggest that E2F1 overexpression can sensitize prostate tumor cells in vivo, independent of p53 or androgen receptor status.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Definition and Validation of “Favorable High-Risk Prostate Cancer”: Implications for Personalizing Treatment of Radiation-Managed Patients

Purpose: To define and validate a classification of favorable high-risk prostate cancer that could be used to personalize therapy, given that consensus guidelines recommend similar treatments for all radiation-managed patients with high-risk disease. Methods and Materials: We studied 3618 patients with cT1-T3aN0M0 high-risk or unfavorable intermediate-risk prostate adenocarcinoma treated with radiation at a single institution between 1997 and 2013. Favorable high-risk was defined as T1c disease with either Gleason 4 + 4 = 8 and prostate-specific antigen <10 ng/mL or Gleason 6 and prostate-specific antigen >20 ng/mL. Competing risks regression was used to determine differences in the risk of prostate cancer–specific mortality (PCSM) after controlling for baseline factors and treatment. Our results were validated in a cohort of 13,275 patients using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Results: Patients with favorable high-risk disease had significantly better PCSM than other men with high-risk disease (adjusted hazard ratio [AHR] 0.42, 95% confidence interval [CI] 0.18-0.996, P=.049) and similar PCSM as men with unfavorable intermediate-risk disease (AHR 1.17, 95% CI 0.50-2.75, P=.710). We observed very similar results within the SEER-Medicare cohort (favorable high-risk vs other high-risk: AHR 0.21, 95% CI 0.11-0.41, P<.001; favorable high-risk vs unfavorable intermediate-risk: AHR 0.67, 95% CI 0.33-1.36, P=.268). Conclusions: Patients with favorable high-risk prostate cancer have significantly better PCSM than other patients with high-risk disease and similar PCSM as those with unfavorable intermediate-risk disease, who are typically treated with shorter-course androgen deprivation therapy. This new classification system may allow for personalization of treatment within high-risk disease, such as consideration of shorter-course androgen deprivation therapy for favorable high-risk disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Nationwide, Multicenter, Retrospective Study on High-Dose-Rate Brachytherapy as Monotherapy for Prostate Cancer

Purpose: To present, analyze, and discuss results of a nationwide, multicenter, retrospective study on high-dose-rate brachytherapy (HDR-BT) as monotherapy for low-, intermediate-, and high-risk prostate cancer. Methods and Materials: From 1995 through 2013, 524 patients, 73 (14%) with low-risk, 207 (40%) with intermediate-risk, and 244 (47%) with high-risk prostate cancer, were treated with HDR-BT as monotherapy at 5 institutions in Japan. Dose fractionations were 27 Gy/2 fractions for 69 patients (13%), 45.5 Gy/7 fractions for 168 (32%), 49 Gy/7 fractions for 149 (28%), 54 Gy/9 fractions for 130 (25%), and others for 8 (2%). Of these patients, 156 (30%) did not receive androgen deprivation therapy, and 202 patients (39%) did receive androgen deprivation therapy <1 year, 112 (21%) for 1-3 years, and 54 (10%) for >3 years. Median follow-up time was 5.9 years (range, 0.4-18.1 years), with a minimum of 2 years for surviving patients. Results: After 5 years, respective actuarial rates of no biochemical evidence of disease, overall survival, cause-specific survival, and metastasis-free survival for all patients were 92%, 97%, 99%, and 94%. For low/intermediate/high-risk patients, the 5-year no biochemical evidence of disease rates were 95%/94%/89%, the 5-year overall survival rates were 98%/98%/94%, the 5-year cause-specific survival rates were 98%/100%/98%, and the 5-year metastasis-free survival rates were 98%/95%/90%, respectively. The cumulative incidence of late grade 2 to 3 genitourinary toxicity at 5 years was 19%, and that of late grade 3 was 1%. The corresponding incidences of gastrointestinal toxicity were 3% and 0% (0.2%). No grade 4 or 5 of either type of toxicity was detected. Conclusions: The findings of this nationwide, multicenter, retrospective study demonstrate that HDR-BT as monotherapy was safe and effective for all patients with low-, intermediate-, and high-risk prostate cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

ASCENDE-RT: An Analysis of Treatment-Related Morbidity for a Randomized Trial Comparing a Low-Dose-Rate Brachytherapy Boost with a Dose-Escalated External Beam Boost for High- and Intermediate-Risk Prostate Cancer

Purpose: To report the genitourinary (GU) and gastrointestinal (GI) morbidity and erectile dysfunction in a randomized trial comparing 2 methods of dose escalation for high- and intermediate-risk prostate cancer. Methods and Materials: ASCENDE-RT (Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy) enrolled 398 men, median age 68 years, who were then randomized to either a standard arm that included 12 months of androgen deprivation therapy and pelvic irradiation to 46 Gy followed by a dose-escalated external beam radiation therapy (DE-EBRT) boost to 78 Gy, or an experimental arm that substituted a low-dose-rate prostate brachytherapy (LDR-PB) boost. At clinic visits, investigators recorded GU and GI morbidity and information on urinary continence, catheter use, and erectile function. Exclusion of 15 who received nonprotocol treatment and correction of 14 crossover events left 195 men who actually received a DE-EBRT boost and 188, an LDR-PB boost. Median follow-up was 6.5 years. Results: The LDR-PB boost increased the risk of needing temporary catheterization and/or requiring incontinence pads. At 5 years the cumulative incidence of grade 3 GU events was 18.4% for LDR-PB, versus 5.2% for DE-EBRT (P<.001). Compared with the cumulative incidence, the 5-year prevalence of grade 3 GU morbidity was substantially lower for both arms (8.6% vs 2.2%, P=.058). The 5-year cumulative incidence of grade 3 GI events was 8.1% for LDR-PB, versus 3.2% for DE-EBRT (P=.124). The 5-year prevalence of grade 3 GI toxicity was lower than the cumulative incidence for both arms (1.0% vs 2.2%, respectively). Among men reporting adequate baseline erections, 45% of LDR-PB patients reported similar erectile function at 5 years, versus 37% after DE-EBRT (P=.30). Conclusions: The incidence of acute and late GU morbidity was higher after LDR-PB boost, and there was a nonsignificant trend for worse GI morbidity. No differences in the frequency of erectile dysfunction were observed.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Testosterone complex and non-steroidal ligands of human aromatase

Cytochrome P450 aromatase (AROM) catalyzes the biosynthesis of estrogen from androgen. Previously crystal structures of human AROM in complex with the substrate androstenedione, and inhibitors exemestane, as well as the newly designed steroidal compounds, have been reported. Here, in this paper, we report the first crystal structure of testosterone complex of human placental AROM. Testosterone binds at the androgen-specific heme distal pocket. The polar and hydrophobic interactions with the surrounding residues resemble the interactions observed for other ligands. The heme proximal region comprises the intermolecular interface in AROM, and also the putative interaction surface of its redox partner cytochrome P450 reductase. Unreported previously, the proximal region is characterized by a large surface cavity, unlike most known P450’s. Using five best X-ray data sets from androstenedione and testosterone complexes of AROM, we now unequivocally show the presence of an unexplained ligand electron density inside the proximal cavity. The density is interpreted as ordered five ethylene glycol units of polyethylene glycols used as a solvent for steroids and also in crystallization. Interestingly, polyethylene glycol exhibits weak inhibition of AROM enzyme activity in a time dependent manner. Besides its critical role in the redox partner coupling and electron transfer process, the proximal cavity possibly serves as the interaction site for other molecules that may have regulatory effects on AROM activity. In addition, the new data also reveal a previously unidentified water channel linking the active site to the lipid interface. The channel could be the predicted passage for water molecules involved in catalysis.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Transcriptomic and phenotypic profiling in developing zebrafish exposed to thyroid hormone receptor agonists

There is a need to develop novel, high-throughput screening and prioritization methods to identify chemicals with adverse estrogen, androgen, and thyroid activity to protect human health and the environment and is of interest to the Endocrine Disruptor Screening Program. The current aim is to explore the utility of zebrafish as a testing paradigm to classify endocrine activity using phenotypically anchored transcriptome profiling. Transcriptome analysis was conducted on embryos exposed to 25 estrogen-, androgen-, or thyroid-active chemicals at a concentration that elicited adverse malformations or mortality at 120 hours post-fertilization in 80% of the animals exposed. Analysis of the top 1000 significant differentially expressed transcripts across all treatments identified a unique transcriptional and phenotypic profile for thyroid hormone receptor agonists, which can be used as a biomarker screen for potential thyroid hormone agonists.

endocrine disruptors↗