Androgen receptor promotes melanoma metastasis via altering the miRNA-539-3p/USP13/MITF/AXL signals

Early studies demonstrated that male melanoma patients have worse survival than female patients, yet the detailed mechanisms for this gender difference remain unclear. We analyzed around 100 cases of human melanoma and found that androgen receptor (AR) positive melanoma patients have worse survival outcomes compared with AR-negative melanoma patients. Here we report that AR can have positive roles to increase melanoma cell invasion in multiple cell lines in vitro and a mouse model in vivo. Mechanism dissection suggest that AR increases melanoma cell invasion via modulating the MITF-AXL signals via altering the miRNA-539-3p/USP13 signaling to increase MITF protein degradation through a reduction of de-ubiquitination. Restoring MITF can reverse AR-enhanced melanoma cell invasion. Together, our results demonstrate that AR can promote melanoma metastasis via altering the miRNA-539-3p/USP13/MITF/AXL signal and targeting this newly identified signal with AR degradation enhancer ASC-J9 may help us to better suppress the melanoma metastasis.

Anti-androgen receptor ASC-J9 versus anti-androgens MDV3100 (Enzalutamide) or Casodex (Bicalutamide) leads to opposite effects on prostate cancer metastasis via differential modulation of macrophage infiltration and STAT3-CCL2 signaling

Despite androgen deprivation therapy (ADT) suppression of prostate cancer (PCa) growth, its overall effects on PCa metastasis remain unclear. Using human (C4-2B/THP1) and mouse (TRAMP-C1/RAW264.7) PCa cells–macrophages co-culture systems, we found currently used anti-androgens, MDV3100 (enzalutamide) or Casodex (bicalutamide), promoted macrophage migration to PCa cells that consequently led to enhanced PCa cell invasion. In contrast, the AR degradation enhancer, ASC-J9, suppressed both macrophage migration and subsequent PCa cell invasion. Mechanism dissection showed that Casodex/MDV3100 reduced the AR-mediated PIAS3 expression and enhanced the pSTAT3-CCL2 pathway. Addition of CCR2 antagonist reversed the Casodex/MDV3100-induced macrophage migration and PCa cell invasion. In contrast, ASC-J9 could regulate pSTAT3-CCL2 signaling using two pathways: an AR-dependent pathway via inhibiting PIAS3 expression and an AR-independent pathway via direct inhibition of the STAT3 phosphorylation/activation. These findings were confirmed in the in vivo mouse model with orthotopically injected TRAMP-C1 cells. Together, these results may raise the potential concern about the currently used ADT with anti-androgens that promotes PCa metastasis and may provide some new and better therapeutic strategies using ASC-J9 alone or a combinational therapy that simultaneously targets androgens/AR signaling and PIAS3-pSTAT3-CCL2 signaling to better battle PCa growth and metastasis at castration-resistant stage.

Androgen receptor (AR) differential roles in hormone-related tumors including prostate, bladder, kidney, lung, breast and liver

The androgen receptor (AR) is expressed in many cell types and the androgen/AR signaling has been found to have important roles in modulating tumorigenesis and metastasis in several cancers including prostate, bladder, kidney, lung, breast and liver. However, whether AR has differential roles in the individual cells within these tumors that contain a variety of cell types remains unclear. Generation of AR knockout (ARKO) mouse models with deletion of AR in selective cells within tumors indeed have uncovered many unique AR roles in the individual cell types during cancer development and progression. This review will discuss the results obtained from various ARKO mice and different human cell lines with special attention to the cell type- and tissue-specific ARKO models. The understanding of various results showing the AR indeed has distinct and contrasting roles in each cell type within many hormone-related tumors (as stimulator in bladder, kidney and lung metastases vs as suppressor in prostate and liver metastases) may eventually help us to develop better therapeutic approaches by targeting the AR or its downstream signaling in individual cell types to better battle these hormone-related tumors in different stages.

Scleritis and multiple systemic autoimmune manifestations in chronic natural killer cell lymphocytosis associated with elevated TCRalpha/beta+CD3+CD4-CD8- double-negative T cells

BACKGROUND/AIMS

Chronic natural killer lymphocytosis (CNKL) has been associated with systemic autoimmunity; however, its association with scleritis or ocular autoimmunity has not been characterised. The natural killer (NK) cell function and immunophenotype of a patient with CNKL who developed bilateral scleritis and multiple systemic autoimmune findings were evaluated.

METHODS

The ophthalmic records of a patient with CNKL and scleritis were reviewed over a 6-year period. Flow cytometry was performed to evaluate T cell, NK and B cell populations. NK cellular functions (ie, NK cytotoxicity and cytokine/chemokine production following interleukin 2 (IL2) stimulation) were evaluated.

RESULTS

A 56-year-old woman with vitiligo, psoriatic arthritis, thyroiditis, erythema nodosum, bilateral anterior scleritis and Sjogren syndrome was managed with multiple immunosuppressive medications, including prednisone, mycophenolate mofetil and methotrexate. Flow cytometry showed a persistent elevation of CD56(+)CD3(-) NK cells greater than 40%, which was consistent with CNKL. NK cell cytotoxicity assay identified a deficiency of K562 cell lysis in the patient (1.46 mean-fold greater in control vs patient). NK cytokine/chemokine production following IL2 stimulation was also deficient (2.5-32.5-fold greater in control). Cytokines/chemokines assessed included pro-inflammatory (interferon gamma, tumor necrosis factor alpha, IL1, monocyte chemotactic protein 1) and immunoregulatory cytokines (IL4, IL5 and IL10). An abnormal elevation of TCRalpha/beta(+) CD3(+)CD4(-)CD8(-) T cells suggestive of autoimmune lymphoproliferative syndrome was observed; however, apoptosis dysfunction was not found.

CONCLUSION

The association of increased but dysfunctional NK cells in the context of multiple systemic and ocular manifestations suggests a role of NK cells in the pathogenesis of our patient's disease. Further studies regarding NK cell dysfunction and ocular autoimmunity are needed.

Spontaneous T cell mediated keratoconjunctivitis in Aire-deficient mice

BACKGROUND/AIMS

Patients with autoimmune polyendocrinopathy-candiasis-ectodermal dystrophy (APECED) develop severe keratoconjunctivitis, corneal scarring and visual loss, but the precise pathogenesis is unknown. This study evaluated the ocular surface immune cell environment, conjunctival goblet cell density and response to desiccating environmental stress of the autoimmune regulatory (Aire) gene knockout murine model of APECED.

METHODS

Aire-deficient and wild type (WT) mice were subjected to desiccating stress from a drafty, low-humidity environment and pharmacological inhibition of tear secretion for 5 days. Immune cell populations (CD4(+), CD8(+), CD11b(+), CD45(+)) and goblet cell density were measured in ocular surface tissues and meibomian glands, and compared with baseline values.

RESULTS

Greater CD4(+) T cell populations were observed in the conjunctival epithelium of Aire-deficient mice (p<0.001) compared with WT. Aire-deficient mice also had greater numbers of CD4(+), CD8(+), and CD11b(+) cells in the peripheral cornea at baseline and following desiccating stress. The meibomian glands of Aire-deficient mice demonstrated greater CD4(+), CD8(+), CD45(+) and CD11b(+) cells at baseline (p<0.001) and following desiccating stress. Conjunctival goblet cell density was lower at baseline and following desiccating stress in Aire-deficient compared with WT mice (p<0.001).

CONCLUSION

Aire-deficiency leads to infiltration of CD4(+) and CD8(+) T cells on the ocular surface and meibomian glands, which is accompanied by goblet cell loss. Desiccating stress promotes this proinflammatory milieu. Immune-mediated mechanisms play a role in the severe blepharitis and keratoconjunctivitis in the murine model of APECED.

Role of the yeast ABC transporter Yor1p in cadmium detoxification

Growth of yeast strains, either deleted for the vacuolar ABC transporter Ycf1 or deleted for the plasma membrane ABC transporter Yor1p or overexpressing Yor1p, were compared for their sensitivity to cadmium. On solid medium cell death (or growth inhibition) was observed at cadmium concentrations higher than 100 microM when yeasts were grown at 30 degrees C for 24 h. However, for all tested strains cell death (or growth inhibition) was already observed at 40 microM cadmium when incubated at 23 degrees C for 60 h. Thus cadmium is more toxic to yeast at 23 degrees C than at 30 degrees C. At 23 degrees C, the Deltayor1 strain grew more slowly than the wild-type strain and the double Deltayor1, Deltaycf1 deleted strain was much more sensitive to cadmium than each single Deltayor1 or Deltaycf1 deletant. Overexpression of Yor1p in a Deltaycf1 strain restores full growth. Cadmium uptake measurements show that Deltaycf1 yeast strains expressing or overexpressing Yor1p store less cadmium than the corresponding Deltaycf1, Deltayor1 strain. The strains expressing Yor1p display an energy-dependent efflux of cadmium estimated for the yeast overexpressing Yor1p to be about 0.02 nmol 109Cd/mg protein/min. Yeast cells loaded with radiolabeled glutathione and then with radioactive cadmium displayed a twice-higher efflux of glutathione than that of cadmium suggesting that Yor1p transports both compounds as a bis-glutathionato-cadmium complex. All together, these results suggest that in addition to being accumulated in the yeast vacuole by Ycf1p, cadmium is also effluxed out of the cell by Yor1p.

The androgen receptor in spermatogenesis

Androgens are steroid hormones that are necessary for normal male phenotype expression, including the outward development of secondary sex characteristics as well as the initiation and maintenance of spermatogenesis. Many physiological actions of androgens are mediated by the androgen receptor (AR), a member of the nuclear receptor superfamily. AR functions as a ligand-dependent transcription factor, regulating expression of an array of target genes that are important in male pubertal development and fertility. In this review, the expression and necessity of AR in specific testicular cell types that are important in spermatogenesis will be discussed, and recent information obtained through the study of complete and cell type-specific AR null mouse models will be presented.

Identification and characterization of a novel androgen receptor coregulator ARA267-alpha in prostate cancer cells

The androgen receptor (AR) is a member of the steroid receptor superfamily that binds to the androgen response element to regulate target gene transcription. AR may need to interact with some selected coregulators for maximal or proper androgen function. Here we report the isolation of a new AR coregulator with a calculated molecular mass of 267 kDa named the androgen receptor-associated protein 267-alpha (ARA267-alpha). ARA267-alpha contains 2427 amino acids, including one Su(var)3-9, Enhancer-of-zeste, and Trithorax (SET) domain, two LXXLL motifs, three nuclear translocation signal (NLS) sequences, and four plant homeodomain (PHD) finger domains. Northern blot analyses reveal that ARA267-alpha is expressed predominantly in the lymph node as 13- and 10-kilobase transcripts. HepG2 is the only cell line tested that does not express ARA267-alpha. Yeast two-hybrid and glutathione S-transferase pull-down assays show that both the N and C terminus of ARA267-alpha interact with the AR DNA- and ligand-binding domains. Unlike other coregulators, such as CBP, which enhance the interaction between the N and C terminus of AR, we found that ARA267-alpha had little influence on the interaction between the N and C terminus of AR. Luciferase and chloramphenicol acetyltransferase assays show that ARA267-alpha can enhance AR transactivation in a dihydrotestosterone-dependent manner in PC-3 and H1299 cells. ARA267-alpha can also enhance AR transactivation with other coregulators, such as ARA24 or PCAF, a histone acetylase, in an additive manner. Together, our data demonstrate that ARA267-alpha is a new AR coregulator containing the SET domain with an exceptionally large molecular mass that can enhance AR transactivation in prostate cancer cells.

Localization of the sentinel node in breast cancer: identical results with same-day and day-before isotope injection

BACKGROUND

Although the technique of sentinel lymph node (SLN) biopsy in breast cancer is not fully standardized, an increasing number of centers map the SLN by using radioisotope supplemented by blue dye, and most have injected isotope on the day of surgery. Here we directly compare the results of same-day and day-before isotope injection in a large series of breast cancer patients having SLN biopsy with our mature technique.

METHODS

Starting with our 961st SLN procedure for breast cancer, 1320 consecutive patients had SLN biopsy after the injection of unfiltered 99mTc-labeled sulfur colloid given as a single-site, low-volume (0.05 ml) intradermal injection: 933 on the day of surgery (1-day protocol) and 387 on the day before (2-day protocol). All had intraparenchymal injection of blue dye.

RESULTS

The two groups were comparable in age, tumor location, histopathologic characteristics, and number of SLNs identified. LSG taken at 2 hours in the 2-day protocol was positive more often than LSG performed at 30 minutes in the 1-day protocol, and nonaxillary sites of lymphatic drainage were seen in <1% of each group. Absolute isotope counts and the ratio of SLN to axillary background counts were similar. Isotope localization of the SLN succeeded in a comparable fraction of patients, as did SLN identification overall.

CONCLUSIONS

The results of SLN mapping with same-day and day-before injection of radioisotope are virtually identical. The logistical advantages of day-before injection do not compromise the success of the procedure.

Quality of life and stimulation of weight gain after treatment with megestrol acetate: correlation between cytokine levels and nutritional status, appetite in geriatric patients with wasting syndrome

BACKGROUND

The geriatric wasting syndrome (GWS) has been associated with proinflammatory cytokines, depression and progressive decline in quality of life (QOL). The objective of this study was to evaluate the correlation between the changes in cytokine levels and appetite, nutritional markers, and QOL in geriatric patients with GWS following a randomized clinical trial of megestrol acetate (MA) versus placebo.

METHODS

This was a prospective, double-blind, placebo-controlled trial. We evaluated 69 predominantly male (3 females) nursing home residents with weight loss of > or =5% of their usual body weight over the past three months or body weight 20% below their ideal body weight. Patients were randomly assigned to receive either placebo or megestrol acetate (MA) oral suspension (O.S.) 800 mg/day for 12 weeks and were then followed for 13 weeks off treatment. Data on appetite, weight, nutritional status, QOL and cytokine levels were collected at baseline and week 12. The correlation between appetite, weight, nutritional status, sense of well being and cytokine level changes in response to MA treatment was examined at week 12.

RESULTS

Appetite, sense of well being, and QOL assessed by an "enjoyment list" significantly improved in the MA arm. Rising prealbumin showed a negative correlation with decreasing IL-6 (r = -0.51), TNFR-p 55 (r = -0.49) and sIL-2R (r = -0.38). There was also an improvement in prealbumin and a decrease in IL-6 and TNFR-p55 in the MA-arm (p < 0.01). A correlation between a decrease in the IL-6 levels and improvement in depression (r = 0.50) was seen in the MA arm as well. Improvement in appetite positively correlated with increased enjoyment of life (r = -0.41), less depression (r = -0.34), improved sense of well being (r = 0.36), prealbumin gain (r = 0.30), and weight gain (r = 0.38) by 12 weeks. Also, improvement in appetite positively correlated with improvement in nutritional parameters such as prealbumin, albumin, fat free mass and weight in the MA arm.

CONCLUSIONS

In a geriatric nursing home population with weight loss, reduction in cytokine levels after MA treatment correlates with improvement in appetite, prealbumin, albumin, and improvement in quality of life.

Akt suppresses androgen-induced apoptosis by phosphorylating and inhibiting androgen receptor

Whereas several apoptosis-related proteins have been linked to the antiapoptotic effects of Akt serine-threonine kinase, the search continues to explain the Akt signaling role in promoting cell survival via antiapoptotic effects. Here, we demonstrate that Akt phosphorylates the androgen receptor (AR) at Ser-210 and Ser-790. A mutation at AR Ser-210 results in the reversal of Akt-mediated suppression of AR transactivation. Activation of the phosphatidylinositol-3-OH kinase/Akt pathway results in the suppression of AR target genes, such as p21, and the decrease of androgen/AR-mediated apoptosis, which may involve the inhibition of interaction between AR and AR coregulators. Together, these findings provide a molecular basis for cross-talk between two signaling pathways at the level of Akt and AR-AR coregulators that may help us to better understand the roles of Akt in the androgen/AR-mediated apoptosis.

Performance characteristics of the COBAS AmpliScreen HIV-1 test, version 1.5, an assay designed for screening plasma mini-pools

BACKGROUND

The COBAS AmpliScreen HIV-1 test, version 1.5 (v1.5) (Roche Molecular Systems), is designed for screening pools composed of samples from 24 individual units of blood or plasma. A specimen-processing procedure (Multiprep) simultaneously concentrates and extracts HIV-1, HCV, and HBV particles from plasma and incorporates an HIV-1 internal control (IC) RNA. Processed samples are amplified by RT-PCR using HIV-1-specific primers and detected by hybridization of the amplified products to HIV-1- and IC-specific oligonucleotide probes.

STUDY DESIGN AND METHODS

Plasma samples containing known quantities of HIV-1 were used to evaluate analytical sensitivity and precision and to validate a pool testing algorithm. Analytical specificity was evaluated by adding various viruses and bacteria to HIV-1-negative plasma. Seroconversion panels were tested to estimate the window-period reduction achieved by RNA testing.

RESULTS

The analytical sensitivity of the test (concentration that yields > or = 95% positive results in a set of replicate tests) was 25 copies of HIV-1 RNA per mL of pooled plasma. Representative strains from all HIV-1 group M subtypes were reproducibly detected (> 95% positive results) at concentrations of 20 to 200 viral particles per mL. The test did not cross-react with a set of 31 viral and 5 bacterial isolates, and it yielded negative results on a panel of 500 blood samples from HIV-1-seronegative donors. Plasma samples containing abnormally high levels of Hb, albumin, triglycerides, or bilirubin did not interfere with the test. HIV-1 RNA was detected 2 to 14 days before HIV-1 antibody and 0 to 28 days before p24 antigen. The test specifically detected pools containing a single positive unit with 2400 HIV-1 RNA copies per mL and correctly identified the positive unit.

CONCLUSION

The COBAS AmpliScreen HIV-1 test, v1.5, has sufficient sensitivity to detect a single infected unit containing 600 copies of HIV-1 per mL in a pool with 23 uninfected units and should reduce the window period between infection and seroconversion by at least 2 to 14 days.

Isoprene increases thermotolerance of fosmidomycin-fed leaves

Isoprene is synthesized and emitted in large amounts by a number of plant species, especially oak (Quercus sp.) and aspen (Populus sp.) trees. It has been suggested that isoprene improves thermotolerance by helping photosynthesis cope with high temperature. However, the evidence for the thermotolerance hypothesis is indirect and one of three methods used to support this hypothesis has recently been called into question. More direct evidence required new methods of controlling endogenous isoprene. An inhibitor of the deoxyxylulose 5-phosphate pathway, the alternative pathway to the mevalonic acid pathway and the pathway by which isoprene is made, is now available. Fosmidomycin eliminates isoprene emission without affecting photosynthesis for several hours after feeding to detached leaves. Photosynthesis of fosmidomycin-fed leaves recovered less following a 2-min high-temperature treatment at 46 degrees C than did photosynthesis of leaves fed water or fosmidomycin-fed leaves in air supplemented with isoprene. Photosynthesis of Phaseolus vulgaris leaves, which do not make isoprene, exhibited increased thermotolerance when isoprene was supplied in the airstream flowing over the leaf. Other short-chain alkenes also improved thermotolerance, whereas alkanes reduced thermotolerance. It is concluded that thermotolerance of photosynthesis is a substantial benefit to plants that make isoprene and that this benefit explains why plants make isoprene. The effect may be a general hydrocarbon effect and related to the double bonds in the isoprene molecule.

From transforming growth factor-beta signaling to androgen action: identification of Smad3 as an androgen receptor coregulator in prostate cancer cells

Although transforming growth factor-beta (TGF-beta) has been identified to mainly inhibit cell growth, the correlation of elevated TGF-beta with increasing serum prostate-specific antigen (PSA) levels in metastatic stages of prostate cancer has also been well documented. The molecular mechanism for these two contrasting effects of TGF-beta, however, remains unclear. Here we report that Smad3, a downstream mediator of the TGF-beta signaling pathway, functions as a coregulator to enhance androgen receptor (AR)-mediated transactivation. Compared with the wild-type AR, Smad3 acts as a strong coregulator in the presence of 1 nM 5alpha-dihydrotestosterone, 10 nM 17beta-estradiol, or 1 microM hydroxyflutamide for the LNCaP mutant AR (mtAR T877A), found in many prostate tumor patients. We further showed that endogenous PSA expression in LNCaP cells can be induced by 5alpha-dihydrotestosterone, and the addition of the Smad3 further induces PSA expression. Together, our findings establish Smad3 as an important coregulator for the androgen-signaling pathway and provide a possible explanation for the positive role of TGF-beta in androgen-promoted prostate cancer growth.

N7: a novel multi-modality therapy of high risk neuroblastoma (NB) in children diagnosed over 1 year of age

BACKGROUND

The N7 protocol for poor-risk neuroblastoma uses dose-intensive chemotherapy (as in N6 protocol [Kushner et al.: J Clin Oncol 12:2607-2613, 1994] but with lower dosing of vincristine) for induction, surgical resection and 2100 cGy hyperfractionated radiotherapy for local control, and for consolidation, targeted radioimmunotherapy with 131I-labeled anti-GD2 3F8 monoclonal antibody and immunotherapy with unlabeled/unmodified 3F8 (400 mg/m2).

PROCEDURE

The chemotherapy consists of: cyclophosphamide 70 mg/kg/d x 2 and a 72-hr infusion of doxorubicin 75 mg/m2 plus vincristine 2 mg/m2, for courses 1, 2, 4, and 6; and cisplatin 50 mg/m2/d x 4 and etoposide 200 mg/m2/d x 3, for courses 3, 5, and 7. 131I-3F8 is dosed at 20 mCi/kg, which is myeloablative and therefore necessitates stem-cell support.

RESULTS

Of the first 24 consecutive previously untreated patients more than 1 year old at diagnosis, 22 were stage 4 and two were unresectable stage 3 with MYCN amplification. Chemotherapy achieved CR/VGPR in 21 of 24 patients. Twenty patients to date have completed treatment with 131I-3F8, and 15 patients have completed all treatment. With a median follow-up of 19 months, 18 of 24 patients remain progression-free.

CONCLUSIONS

Major toxicities were grade 4 myelosuppression and mucositis during chemotherapy, and self-limited pain and urticaria during antibody treatment. Late effects include hearing deficits and hypothyroidism.

Noninvasive determination of hemoglobin and hematocrit using a temperature-controlled localized reflectance tissue photometer

We performed visible/near-infrared optical measurements on the forearm of human subjects. We conducted four studies: one study using a commercial diffuse reflectance spectrometer, and three studies using a breadboard temperature-controlled localized reflectance tissue photometer. Calibration relationships were established between skin reflectance signal and either the reference blood hemoglobin (Hb) concentration or the hematocrit values (Hct). Prediction results were expressed as the prediction correlation coefficient (r(p)) and the standard error for cross-validation prediction (CV-SEP). Using diffuse reflectance measurement, r(p) = 0. 8, CV-SEP = 0.9 g/dL for Hb and r(p) = 0.7, CV-SEP = 3.3% for Hct (n = 40). In a localized reflectance study involving calculating the absorption and scattering coefficients and including effect of change of skin temperature in the calibration model, the best prediction results were r(p) = 0.9, CV-SEP = 0.8 g/dL for Hb and r(p) = 0.8, CV-SEP = 3% for Hct (n = 26). In a second localized reflectance study on a population having diverse skin colors at 34 degrees C, the optimal model led to r(p) = 0.8, CV-SEP = 0.9 g/dL for Hb and r(p) = 0.9, CV-SEP = 2.1% for Hct (n = 28) using the localized reflectance values without deducing the absorption and scattering coefficients. Improvement in the correlation was more noticeable for Hct than for the case of Hb. The photometer was used to screen prospective blood donors with low Hb concentration. It was possible to predict anemic subjects in the limited prospective blood donor population.

Functional analysis of androgen receptor N-terminal and ligand binding domain interacting coregulators in prostate cancer

Several new androgen receptor (AR) coregulators, including ARA70, ARA55, ARA54, ARA160 and ARA24, associated with the N-terminal or the ligand-binding domain (LBD) of AR, have been identified by our group. We first identified the AR-LBD coregulators ARA70, ARA55, and ARA54. Our previous reports suggest that ARA70 can enhance the androgenic activity of 17 beta-estradiol (E2) and antiandrogens toward AR. It is of interest to compare and determine if the specificity of sex hormones and antiandrogens can be modulated by different coregulators. Our results indicate that, ARA70 is the best coregulator for increasing the androgenic activity of E2. Only ARA70 and ARA55 were able to significantly increase the androgenic activity of hydroxyflutamide, the active metabolite of a widely-used antiandrogen for the treatment of prostate cancer. Furthermore, our results suggest that among the LBD coregulators, ARA70 has a relatively high specificity for AR in the human prostate cancer cell line DU145. Together, our data suggest that the androgenic activity of some sex hormones and antiandrogens can be modulated by selective AR coactivators. In addition to the AR-LBD associated proteins, ARA24 and ARA160 have been identified as AR coregulators, interacting with the AR N-terminal instead of the LBD. Functional analysis revealed that the AR N-terminal coregulator ARA160 could cooperate with the AR LBD-associated coregulator ARA70. Our data indicate that ARA24 could also interact with AR, and that this binding is decreased by an expanding poly-glutamine (Q) length within AR. The length of the poly-Q stretch in the AR N-terminal domain is inversely correlated with the transcriptional activity of AR. Our data suggest that optimal AR transactivation may require interaction of AR with AR coregulators. The identification of factors or peptides that can interrupt androgen-mediated AR-ARA interactions may be useful in the development of better antiandrogens for treating androgen-related diseases, such as prostate cancer.

Chitinase genes responsive to cold encode antifreeze proteins in winter cereals

Antifreeze proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-antifreeze proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.

Chitinase genes responsive to cold encode antifreeze proteins in winter cereals

Antifreeze proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-antifreeze proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.

Increase of androgen-induced cell death and androgen receptor transactivation by BRCA1 in prostate cancer cells

Although mutations of the breast cancer susceptibility gene 1 (BRCA1) may play important roles in breast and prostate cancers, the detailed mechanism linking the functions of BRCA1 to these two hormone-related tumors remains to be elucidated. Here, we report that BRCA1 interacts with androgen receptor (AR) and enhances AR target genes, such as p21((WAF1/CIP1)), that may result in the increase of androgen-induced cell death in prostate cancer cells. The BRCA1-enhanced AR transactivation can be further induced synergistically with AR coregulators, such as CBP, ARA55, and ARA70. Together, these data suggest that the BRCA1 may function as an AR coregulator and play positive roles in androgen-induced cell death in prostate cancer cells and other androgen/AR target organs.

Experience with PCR screening

The COBAS AmpliScreen Hepatitis C (HCV) Test, Version 2.0, which is designed for screening pools composed of samples from individual units of blood or plasma, employs a MultiPrep sample processing procedure that simultaneously extracts and concentrates HCV, HIV-1 and Hepatitis B virus particles from plasma. An HCV Internal Control (IC) RNA serves as an extraction and amplification control for each independently processed sample. Processed samples are amplified by RT-PCR using HCV-specific complementary primers and detected by hybridization of the amplified products to HCV- and IC-specific oligonucleotide probes. The analytical sensitivity of the test is 25 International Units (IU) of HCV per mL of pooled plasma; all HCV genotypes are detected with similar efficiency. The test detected HCV RNA 23 to 32 days prior to anti-HCV antibody seroconversion for four of the five seroconversion panels tested. The test had sufficient sensitivity to reproducibly detect a single infected unit containing 2.4 x 10(3) copies of HCV per mL in a pool with 23 uninfected units. COBAS AmpliScreen tests for HIV-1 and HBV now being validated by Roche Molecular Systems also incorporate the MultiPrep specimen processing method, thereby making it possible to use a single processed specimen to screen for all three viruses.

Development, validation and application of assays to quantify metrifonate and 2,2-dichlorovinyl dimethylphosphate in human body fluids

Gas chromatographic procedures [GC with electron-capture detection (ECD) and GC-MS] for the quantitative analysis of metrifonate and its active metabolite 2,2-dichlorovinyl dimethylphosphate (DDVP) in human blood and urine were developed, validated, and applied to the analysis of clinical study samples. Analysis of metrifonate involved extraction of acidified blood with ethyl acetate followed by solid-phase clean-up of the organic extract. Acidified urine was extracted with dichloromethane and the residue of evaporated organic phase was reconstituted in toluene. ECD and diethyl analogue of metrifonate internal standard (I.S.) were used for quantitation of metrifonate. The metrifonate lower limit of quantitation (LOQ) was 10.0 microg/l. The DDVP metabolite was chromatographed separately after cyclohexane extraction of acidified blood and urine using d6-DDVP I.S. and MS detection. The LOQ of DDVP was 1 microg/l. Stability studies have confirmed that the matrix should be acidified prior to storage at -20 degrees C or -80 degrees C to inhibit chemical and enzymatic degradation of the analytes and to avoid overestimation of DDVP concentrations. Metrifonate was found to be stable in acidified human blood after 20 months of storage at -20 degrees C and after 23 months of storage at -80 degrees C. Under these conditions DDVP was found to be stable after 12 months of storage. Both assay procedures were cross-validated by different world-wide laboratories and found to be accurate and robust during analyses of clinical study samples.

Effects of parenteral infusion with medium-chain triglycerides and safflower oil emulsions on hepatic lipids, plasma amino acids and inflammatory mediators in septic rats

This study was designed to investigate the effects of preinfusion with total parenteral nutrition (TPN) using medium-chain triglycerides (MCT) versus safflower oil (SO) emulsion as fat sources on hepatic lipids, plasma amino acid profiles, and inflammatory-related mediators in septic rats. Normal rats, with internal jugular catheters, were divided into two groups and received TPN. TPN provided 300kcal/kg/day with 40% of the non-protein energy provided as fat. All TPN solutions were isonitrogenous and identical in nutrient composition except for the fat emulsion, which was made of SO or a mixture of MCT and soybean oil (9:1) (MO). After receiving TPN for 6 days, each group of rats was further divided into control and sepsis subgroups. Sepsis was induced by cecal ligation and puncture, whereas control rats received sham operation. All rats were classified into four groups as follows: MCT control group (MOC, n= 8), MCT sepsis group (MOS, n= 8), safflower oil control group (SOC, n= 8), and safflower oil sepsis group (SOS, n= 11). The results of the study demonstrated that the MOS group had lower hepatic lipids than did the SOS group. Plasma leucine and isoleucine levels were significantly lower in the SOS than in the SOC group, but no differences in these two amino acids were observed between the MOC and MOS groups. Plasma arginine levels were significantly lower in septic groups than in those without sepsis despite whether MCT or safflower oil was infused. Plasma glutamine and alanine levels, however, did not differ between septic and non-septic groups either in the SO or MO groups. No differences in interleukin-1b, interleukin-6, tumor necrosis factor-alpha, and leukotriene B(4)concentrations in peritoneal lavage fluid were observed between the two septic groups. These results suggest that catabolic reaction is septic rats preinfused MCT is not as obvious as those preinfused safflower oil. Compared with safflower oil, TPN with MCT administration has better effects on reducing sepsis-induced liver fat deposition. Preinfusion with MCT before sepsis, however, had no effect on inflammatory-related cytokines or leukotriene in peritoneal lavage fluid. In addition, plasma arginine appears to be a more sensitive indicator than glutamine for septic insult.

Performance characteristics of the AmpliScreen HIV-1 test, an assay designed for screening plasma mini-pools

This study evaluated the performance characteristics of the AmpliScreen(TM)Human Immunodeficiency Virus-Type 1 (HIV-1) Test, Version 1.5, a test designed for screening pools composed of samples from individual units of blood or plasma. HIV-1, hepatitis C (HCV) and hepatitis B (HBV) virus particles were simultaneously extracted and concentrated from plasma by a multi-prep sample processing procedure. An HIV-1 Internal Control (IC) RNA was added to each sample to serve as an extraction and amplification control. Processed samples were amplified by RT-PCR using HIV-1-specific complementary primers and detected by hybridization of the amplified products to HIV-1- and IC-specific oligonucleotide probes. The analytical sensitivity of the test (concentration that yields >/=95% positive results in a set of replicate tests) was 25 copies of HIV-1 RNA per mL of pooled plasma. Representative strains from all HIV-1 group M subtypes were reproducibly detected (>95% positive results among 22 replicate tests) at concentrations of 30 to 75 viral particles per ml. The test exhibited excellent specificity; it did not cross-react with a set of 30 viral and five bacterial isolates and yielded negative results on a panel of 500 blood samples from HIV-1 seronegative donors. Samples containing abnormally high levels of haemoglobin, albumin, triglycerides or bilirubin in plasma samples did not interfere with the detection of HIV-1 RNA at a concentration of 100 copies of per ml. The test detected HIV-1 RNA 7-17 days prior to anti-HIV-1 antibody seroconversion for all 10 seroconversion panels tested. A fully automated COBAS AmpliScreen(TM)version of this test is being validated. COBAS AmpliScreen tests for HCV and HBV also incorporate the multi-prep specimen processing method, thereby making it possible to use a single processed specimen to screen for all three viruses.

Differential induction of androgen receptor transactivation by different androgen receptor coactivators in human prostate cancer DU145 cells

Recently identified androgen receptor (AR) coactivators were used in this study to determine whether the specificity of sex hormones and antiandrogens could be modulated at the coactivator level. We found that ARA70 is the best coactivator to confer the androgenic activity on 17beta-estradiol. Only ARA70 and ARA55 could increase significantly the androgenic activity of hydroxyflutamide, a widely used antiand rogen for the treatment of prostate cancer. None of the AR coactivators we tested could significantly confer androgenic activity on progesterone and glucocorticoid at their physiological concentrations (1-10nM). We also found that ARA70, ARA55, and ARA54, but not steroid receptor coactivator-1 (SRC-1) and Rb, could significantly enhance the delta5-androstenediol-mediated AR transactivation. Furthermore, in comparing the relative specificity of these coactivators to AR in DU145 cells, our results suggested that ARA70 has a relatively higher specificity and that SRC-1 can enhance almost equally well many other steroid receptors. Finally, our data demonstrated that AR itself and some select AR coactivators such as ARA70 or ARA54 could, respectively, interact with CBP and p300/CBP-associated factors that have histone acetyl-transferase activity for assisting chromatin remodeling. Together, our data suggest that the specificity of sex hormones and antiandrogens can be modulated by some selective AR coactivators. These findings may not only help us to better understand the specificity of the sex hormones and antiandrogens, but also facilitate the development of better antiandrogens to fight the androgen-related diseases, such as prostate cancer.

Suppression of Delta(5)-androstenediol-induced androgen receptor transactivation by selective steroids in human prostate cancer cells

Our earlier report suggested that androst-5-ene-3beta,7beta-diol (Delta(5)-androstenediol or Adiol) is a natural hormone with androgenic activity and that two potent antiandrogens, hydroxyflutamide (Eulexin) and bicalutamide (Casodex), fail to block completely the Adiol-induced androgen receptor (AR) transactivation in prostate cancer cells. Here, we report the development of a reporter assay to screen several selective steroids with anti-Adiol activity. Among 22 derivatives/metabolites of dehydroepiandrosterone, we found 4 steroids [no. 4, 1,3,5(10)-estratriene-17alpha-ethynyl-3, 17beta-diol; no. 6, 17alpha-ethynyl-androstene-diol; no. 8, 3beta, 17beta-dihydroxy-androst-5-ene-16-one; and no. 10, 3beta-methylcarbonate-androst-5-ene-7,17-dione] that have no androgenic activity and could also block the Adiol-induced AR transactivation in prostate cancer PC-3 cells. Interestingly, these compounds, in combination with hydroxyflutamide, further suppressed the Adiol-induced AR transactivation. Reporter assays further showed that these four anti-Adiol steroids have relatively lower glucocorticoid, progesterone, and estrogenic activity. Together, these data suggest some selective steroids might have anti-Adiol activity, which may have potential clinical application in the battle against the androgen-dependent prostate cancer growth.

Identification of ARA70 as a ligand-enhanced coactivator for the peroxisome proliferator-activated receptor gamma

In an effort to understand transcriptional regulation by the peroxisome proliferator-activated receptor gamma (PPARgamma), we have investigated its potential interaction with coregulators and have identified ARA70 as a ligand-enhanced coactivator. ARA70 was initially described as a coactivator for the androgen receptor (AR) and is expressed in a range of tissues including adipose tissue (Yeh, S., and Chang, C. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 5517-5521). Here we show that ARA70 and PPARgamma specifically interact by coimmunoprecipitation and in a mammalian two-hybrid assay. PPARgamma and ARA70 interact in the absence of the PPARgamma ligand 15-deoxy-Delta12,14-prostaglandin J2, although the addition of exogenous ligand enhances this interaction. Similarly, in transient transfection of DU145 cells, cotransfection of PPARgamma and ARA70 induces transcription from reporter constructs driven by either three copies of an isolated PPAR response element or the natural promoter of the adipocyte fatty acid-binding protein 2 in the absence of exogenous 15-deoxy-Delta12,14-prostaglandin J2. However, this PPARgamma-ARA70 transactivation is enhanced by the addition of ligand. Thus, ARA70 can function as a ligand-enhanced coactivator of PPARgamma. Finally, we show that AR can squelch PPARgamma-ARA70 transactivation, which suggests that cross-talk may occur between PPARgamma- and AR-mediated responses in adipocytes.

Differential induction of the androgen receptor transcriptional activity by selective androgen receptor coactivators

Several new androgen receptor (AR) cofactors, associated to the ligand binding domain of AR, have been identified by our group and named AR associated protein (ARA)70, ARA55, and ARA54. Our previous reports have suggested that the cofactor ARA70 can confer the androgenic effect from 17 beta-estradiol (E2) and antiandrogen to AR. It is of interest for us to compare and determine if the specificity of sex hormones and antiandrogens could be modulated by different coactivators. Our results indicate that ARA70 is the best coactivator to confer the androgenic activity on E2. Only ARA70 and ARA55 could increase significantly the androgenic activity of hydroxyflutamide, a widely used antiandrogen for the treatment of prostate cancer. Furthermore, as compared to the relative specificity of these coactivators to AR in the prostate cancer DU145 cells, our results suggest that ARA70 has a relatively higher specificity. Together, our data suggest that the specificity of sex hormones and antiandrogens can be modulated by some selective AR coactivators. These findings may not only help us to better understand the specificity of the sex hormones and antiandrogens, but also to facilitate the development of better antiandrogens or androgens to fight the androgen-related diseases, such as prostate cancer.

Isolation of Ku70-binding proteins (KUBs)

DNA-dependent protein kinase (DNA-PK) plays a critical role in resealing DNA double-stand breaks by non-homologous end joining. Aside from DNA-PK, XRCC4 and DNA ligase IV, other proteins which play a role(s) in this repair pathway remain unknown; DNA-PK contains a catalytic subunit (DNA-PKcs) and a DNA binding subunit (Ku70 and Ku80). We isolated Ku70-binding proteins (KUB1-KUB4) using yeast two-hybrid analyses. Sequence analyses revealed KUB1 to be apolipoprotein J (apoJ), also known as X-ray-inducible transcript 8 (XIP8), testosterone-repressed prostate message-2 (TRPM-2) and clusterin. KUB2 is Ku80. KUB3 and KUB4 are unknown, >10 kb trans-cripts. Interactions of apoJ/XIP8 or KUB3 with Ku70 were confirmed by co-immunoprecipitation analyses in MCF-7:WS8 breast cancer or IMR-90 normal lung fibroblast cells, respectively. The interaction of apoJ/XIP8 with Ku70 was confirmed by far-western analyses. Stable over-expression of full-length apoJ/XIP8 in MCF-7:WS8 caused decreased Ku70/Ku80 DNA end binding that was restored by apoJ/XIP8 monoclonal antibodies. The role of apoJ/XIP8 in ionizing radiation resistance/sensitivity is under investigation.

From HER2/Neu signal cascade to androgen receptor and its coactivators: a novel pathway by induction of androgen target genes through MAP kinase in prostate cancer cells

Overexpression of the HER2/Neu protooncogene has been linked to the progression of breast cancer. Here we demonstrate that the growth of prostate cancer LNCaP cells can also be increased by the stable transfection of HER2/Neu. Using AG879, a HER2/Neu inhibitor, and PD98059, a MAP kinase inhibitor, as well as MAP kinase phosphatase-1 (MPK-1), in the transfection assay, we found that HER2/Neu could induce prostate-specific antigen (PSA), a marker for the progression of prostate cancer, through the MAP kinase pathway at a low androgen level. Reporter assays and mammalian two-hybrid assays further suggest this HER2/Neu-induced androgen receptor (AR) transactivation may function through the promotion of interaction between AR and AR coactivators, such as ARA70. Furthermore, we found this HER2/Neu --> MAP kinase --> AR-ARAs --> PSA pathway could not be blocked completely by hydroxyflutamide, an antiandrogen used in the treatment of prostate cancer. Together, these data provide a novel pathway from HER2/Neu to AR transactivation, and they may represent one of the reasons for the PSA re-elevation and hormone resistance during androgen ablation therapy in prostate cancer patients.

Cloning and characterization of human prostate coactivator ARA54, a novel protein that associates with the androgen receptor

Androgen receptor (AR) is a member of the steroid receptor superfamily that may require coactivators for proper or maximal transactivation. Using a yeast two-hybrid screening followed by mammalian cell analyses, we identified a novel ligand-dependent AR-associated protein, ARA54, which consists of 474 amino acids with a molecular mass of 54 kDa. We demonstrated that ARA54 might function as a preferential coactivator for AR-mediated transactivation in human prostate cancer DU145 cells. Interestingly, our data also showed that ARA54 could significantly enhance the transcriptional activity of LNCaP mutant AR (ARt877a) but not wild type AR or another mutant AR (ARe708k) in the presence of 10 nM 17beta-estradiol or 1 microM hydroxyflutamide. These results imply that both ARA54 and the positions of the AR mutation (877 versus 708) might contribute to the specificity of AR-mediated transactivation. Our findings further demonstrated that the C-terminal domain of ARA54 can serve as a dominant negative inhibitor and exogenous full-length ARA54 can reverse this squelching effect on AR transcriptional activity. Co-expression of ARA54 with other AR coactivators, such as ARA70 or SRC-1, showed additive stimulation of AR-mediated transactivation, which indicates that these cofactors may function individually as AR coactivators to induce AR target gene expression. Through our findings, we have identified and characterized a novel AR coactivator, ARA54, which may play an important role in the AR signaling pathway in human prostate.

Cloning and characterization of androgen receptor coactivator, ARA55, in human prostate

Androgen receptor (AR) is a hormone-activated transcriptional factor that can bind to androgen response elements and that regulates the transcription of target genes via a mechanism that presumably involves cofactors. We report here the cloning of a novel AR coactivator ARA55 using a yeast two-hybrid system. ARA55 consists of 444 amino acids with the predicted molecular mass of 55 kDa and its sequence shows very high homology to mouse hic5, a TGF-beta1-inducible gene. Yeast and mammalian two-hybrid systems and co-immunoprecipitation assays all prove ARA55 can bind to AR in a ligand-dependent manner. Transient transfection assay in prostate cancer DU145 cells further demonstrates that ARA55 can enhance AR transcriptional activity in the presence of 1 nM dihydrotestosterone or its antagonists such as 100 nM 17beta-estradiol or 1 microM hydroxyflutamide. Our data also suggest the C-terminal half of ARA55, which includes three LIM motifs, is sufficient to interact with AR. Northern blot and polymerase chain reaction quantitation showed ARA55 can be expressed differently in normal prostate and prostate tumor cells. Together, our data suggests that ARA55 may play very important roles in the progression of prostate cancer by the modulation of AR transactivation.

Delta5-androstenediol is a natural hormone with androgenic activity in human prostate cancer cells

It is known that androst-5-ene-3beta,17beta-diol (Adiol), a precursor of testosterone (T), can activate estrogen target genes. The androgenic activity of Adiol itself, however, is poorly understood. Using a transient transfection assay, we here demonstrate in human prostate cancer cells that Adiol can activate androgen receptor (AR) target genes in the presence of AR, and that AR coactivator ARA70 can further enhance this Adiol-induced AR transcriptional activity. In contrast to this finding, an active metabolite of dehydroepiandrosterone, 7-oxo-dehydroepiandrosterone, does not activate AR target gene in the absence or presence of ARA70. Thin layer chromatography analysis reveals that T, dihydrotestosterone, and 17beta-estradiol are undetectable in human prostate cancer DU145 cells after treatment with Adiol. Additionally, a proteolysis assay shows that a distinct ligand-receptor conformational difference exists between T-AR and Adiol-AR. Together, the above findings and the fact that T, but not Adiol, can induce transcriptional activity in a mutant AR (mtAR708), suggest that, without being metabolized into T, Adiol itself may represent a natural hormone with androgenic activity in human prostate cancer cells. Because two potent antiandrogens, hydroxyflutamide (Eulexin), and bicalutamide (casodex), that are widely used for the treatment of prostate cancer, fail to block Adiol-mediated induction of AR transcriptional activity in prostate cancer cells, the effectiveness of so-called "total androgen blockage," a standard treatment for prostate cancer, may need to be reevaluated.

Retinoblastoma, a tumor suppressor, is a coactivator for the androgen receptor in human prostate cancer DU145 cells

The retinoblastoma protein may function as a tumor suppressor by controlling the progression of the normal cell cycle. Inactivation of Rb has been regarded as an important event in prostate carcinogenesis. However, the detailed mechanism of how Rb is linked to androgen-androgen receptor (A-AR), the major factor in promotion of prostate tumor growth, remains unclear. Using GST-Rb pull down assay and mammalian two-hybrid system, we report here that Rb can bind specifically to AR in an androgen-independent manner. Transient transfection assay demonstrates that cotransfection of AR and Rb can further induce AR transcriptional activity 4-fold in the presence of 1 nM dihydrotestosterone in DU145 cells. Interestingly, cotransfection of Rb and ARA70, the first identified AR coactivator, with AR can additively induce AR transcriptional activity 13-fold (from 5-fold to 64-fold). In conclusion, our discovery that Rb can function as a coactivator to induce AR transcriptional activity in prostate cells may represent the first data to link a negative growth regulatory protein function in a positive manner, by inducing the transcriptional activity of AR.

Promotion of agonist activity of antiandrogens by the androgen receptor coactivator, ARA70, in human prostate cancer DU145 cells

Although hormone therapy with antiandrogens has been widely used for the treatment of prostate cancer, some antiandrogens may act as androgen receptor (AR) agonists that may result in antiandrogen withdrawal syndrome. The molecular mechanism of this agonist response, however, remains unclear. Using mammalian two-hybrid assay, we report that antiandrogens, hydroxyflutamide, bicalutamide (casodex), cyproterone acetate, and RU58841, and other compounds such as genistein and RU486, can promote the interaction between AR and its coactivator, ARA70, in a dose-dependent manner. The chloramphenicol acetyltransferase assay further demonstrates that these antiandrogens and related compounds significantly enhance the AR transcriptional activity by cotransfection of AR and ARA70 in a 1:3 ratio into human prostate cancer DU145 cells. Our results suggest that the agonist activity of antiandrogens might occur with the proper interaction of AR and ARA70 in DU145 cells. These findings may provide a good model to develop better antiandrogens without agonist activity.

From estrogen to androgen receptor: a new pathway for sex hormones in prostate

While all three coactivators ARA70, steroid receptor coactivator 1, and RAC3/ACTR can enhance androgen receptor (AR) transcriptional activity at 1 nM dihydrotestosterone, we here demonstrate that only ARA70 can induce AR transcriptional activity >30-fold in the presence of 10 nM 17beta-estradiol (E2), but not diethylstilbestrol. The significance of this newly described E2-induced AR transcriptional activity in DU145 human prostate cancer cells was further strengthened by finding patients with Reifenstein partial-androgen-insensitive syndrome that fail in the E2-AR-ARA70 pathway. Together, our data suggest, for the first time, testosterone/dihydrotestosterone may not be the only ligands for the AR. E2 represents another important natural ligand for AR that may play an essential role for the AR function and the development of the male reproductive system.

An SRRC elliptically polarizing undulator prototype to examine mechanical design feasibility and magnetic field performance

In this work, a 1 m long Sasaki-type elliptically polarizing undulator (EPU) prototype with 5.6 cm period length is used to examine the mechanical design feasibility as well as magnetic field performance. The magnetic field characteristics of the EPU5.6 prototype at various phase shifts and gap motion are described. The field errors from mechanical tolerances, magnet block errors, end field effects and phase/gap motion effects are analysed. The procedures related to correcting the field with the block position tuning, iron shimming and the trim blocks at both ends are outlined.

Advanced field-measurement method with three orthogonal Hall probes for an elliptically polarizing undulator

A three-orthogonal-Hall-probe assembly with an 'on the fly' mapping method has been developed to characterize an elliptically polarizing undulator (EPU). The underlying design concept is that it can measure the three real field components without any field correction under a reliable and synchronization measurement method. Therefore, the relative central position shift, orthogonal angle and the planar Hall effect error between the three Hall probes should be calibrated and readjusted. Experimental results demonstrate that this method can yield an r.m.s. reproducibility of 10 G cm for the three field components and 2 G for the peak field strength. Under precision conditions this system can completely measure the three on-axis field components within 2 min for a 4 m-long EPU.

Segmental mastectomy and tamoxifen alone provide adequate locoregional control of breast cancer in elderly women

We wished to determine whether tamoxifen and local excision without breast radiation or axillary lymph node dissection provides adequate local and regional control of breast cancer in elderly women. The records of 36 women with breast cancer who were more than 70 years old and were treated only with tamoxifen and local excision from January 1985 to July 1996 were retrospectively reviewed. These patients had refused, or were considered too ill for, standard therapy. The mean follow-up was 44.1 months. Twenty-two (61%) were alive without disease, and six (17%) died of unrelated causes, without recurrence. Two (6%) were alive with metastasis, and five (14%) died with metastasis. One patient developed a breast recurrence, which was reexcised. A second patient developed metastasis and axillary recurrence, which was treated with modified radical mastectomy. Pathologic grade, tumor size, and estrogen receptor and margin status were not predictive of recurrence. In conclusion, despite the omission of breast radiation and axillary dissection, there were only two locoregional recurrences, and both were easily treated surgically. In this select group of patients, local excision and tamoxifen provided adequate locoregional control of breast cancer in elderly women.