Prostatic Acid Research Articles

Enhanced Photodynamic Anticancer Activities of Multifunctional Magnetic Nanoparticles (Fe₃O₄) Conjugated with Chlorin e6 and Folic Acid in Prostate and Breast Cancer Cells.

Photodynamic therapy (PDT) is a promising alternative to conventional cancer treatment methods. Nonetheless, improvement of in vivo light penetration and cancer cell-targeting efficiency remain major challenges in clinical photodynamic therapy. This study aimed to develop multifunctional magnetic nanoparticles conjugated with a photosensitizer (PS) and cancer-targeting molecules via a simple surface modification process for PDT. To selectively target cancer cells and PDT functionality, core magnetic (Fe3O4) nanoparticles were covalently bound with chlorin e6 (Ce6) as a PS and folic acid (FA). When irradiated with a 660-nm long-wavelength light source, the Fe3O4-Ce6-FA nanoparticles with good biocompatibility exerted marked anticancer effects via apoptosis, as confirmed by analyzing the translocation of the plasma membrane, nuclear fragmentation, activities of caspase-3/7 in prostate (PC-3) and breast (MCF-7) cancer cells. Ce6, used herein as a PS, is thus more useful for PDT because of its ability to produce a high singlet oxygen quantum yield, which is owed to deep penetration by virtue of its long-wavelength absorption band; however, further in vivo studies are required to verify its biological effects for clinical applications.

Abstract A95: Prostatic alpha-linolenic acid (ALA) is positively associated with aggressive prostate cancer: A relationship which may depend on genetic variation in ALA metabolism

Abstract Previous observational studies have reported associations between prostate cancer and alpha-linolenic acid (ALA), the most commonly consumed omega-3 polyunsaturated fatty acid in a Western diet. However, few investigations have been able to study this relationship prospectively and in well-controlled settings. Moreover, to date, no studies have determined whether single nucleotide polymorphisms (SNPs) that influence ALA metabolism are associated with this common cancer. The purpose of this study was to explore associations between prostatic levels of ALA, SNPs and prostate cancer-specific biomarkers in samples collected from a previous randomized clinical trial conducted using a presurgical model and which tested the effects of 30 g/d of flaxseed, a rich source of ALA, for ∼30 days prior to prostatectomy (n=134). Serum prostate-specific antigen (PSA) was determined and immunohistochemistry was used to assess tumor Ki67 staining (proliferation rate). Prostatic ALA was determined with gas chromatography. Seven previously identified SNPs (rs99780, rs174537, rs174545, rs174572, rs498793, rs3834458 and rs968567) were tested for associations with prostatic ALA, PSA and Ki67. Despite consuming nearly seven times more ALA per day, men in the flaxseed arm had similar amounts of prostatic ALA relative to men not consuming flaxseed [median (range) 0 (0-9.41) versus 0 (0-0.85), p=0.296. In unadjusted analysis, there were significant positive associations between prostatic ALA and PSA (ρ=0.191, p=0.028) and Ki67 (ρ=0.186, p=0.037). After adjusting for covariates (flaxseed, age, race, BMI and statin-use) the association between ALA and PSA remained (p=0.004) but was slightly attenuated for Ki67 (p=0.051). We did not observe associations between any of the SNPs studied and prostatic ALA; however, in models for PSA there was a significant interaction between rs498793 and ALA (p=0.017) and for Ki67 there were significant interactions with ALA and rs99780 (p=0.033) and rs174545 (p=0.047). An independent association between rs174572 and Ki67 was observed (p=0.007). This study provides evidence that prostatic ALA, independent of the amount of ALA consumed, is positively associated with biomarkers of aggressive prostate cancer. This study also observed for the first time that SNPs related to ALA metabolism may modify the association between ALA and prostate cancer. Citation Format: Maria Azrad, Robert W. Hardy, Wendy Demark-Wahnefried, Kui Zhang, Robin T. Vollmer, John Madden, Thomas Polascik, Denise C. Snyder, Mack T. Ruffin, Judd Moul, Dean Brenner. Prostatic alpha-linolenic acid (ALA) is positively associated with aggressive prostate cancer: A relationship which may depend on genetic variation in ALA metabolism. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A95.

Chronic ethanol consumption alters metabolism and signaling of all-trans-retinoic acid in the prostate

Chronic ethanol consumption alters metabolism and signaling of all-trans-retinoic acid in the prostate

Abstract 4480: Associations between phytanic acid and alpha-methylacyl-CoA racemase (AMACR) expression in the normal human prostate

Abstract Alpha-methylacyl-CoA racemase (AMACR) is an enzyme that is overexpressed in prostate cancer, with lower levels present in normal prostatic tissues. AMACR is involved in the metabolism of phytanic acid - a branched chain saturated fatty acid that has been linked with elevated risks of prostate cancer in several epidemiologic studies. Although considerable research has been done on AMACR as a clinical biomarker in prostate cancer, no study has evaluated the possible link between phytanic acid and AMACR gene expression in the normal human prostate, and thus the possibility that AMACR plays a causal role in prostate carcinogenesis. Fasting blood and histologcally benign prostate tissue samples were obtained from 31 men undergoing radical prostatectomy for the treatment of localized disease. Concentrations of phytanic acid in serum and tissues were determined by isotope dilution gas chromatography-mass spectrometry. RNA was extracted from epithelial cells isolated from fresh-frozen prostate tissues by laser capture microdissection, and AMACR mRNA levels were quantified using real time polymerase chain reaction. Tissue phytanic acid concentrations were not significantly correlated with serum levels nor with prostatic AMACR mRNA levels. Notably, AMACR was significantly inversely correlated with body mass index (Spearman correlation coefficient (r)= –0.43, p=0.02) and directly correlated with Gleason score (r=0.35, p=0.05). Stratification by body mass index revealed an unexpected inverse correlation between wAMACR gene expression levels and phytanic acid concentrations in the prostate (r= –0.95, p= 0.001) in obese men. In conclusion, blood and tissue levels of phytanic acid were not correlated, which suggests that blood measures should not be utilized as a surrogate measure of this fatty acid in the target organ. Contrary to expectation, tissue phytanic acid levels were significantly inversely associated with AMACR gene expression levels in the prostate, but only among obese men.These findings require confirmation in other, larger studies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4480. doi:1538-7445.AM2012-4480

Antigen Specific T-Cell Responses Against Tumor Antigens are Controlled by Regulatory T Cells in Patients With Prostate Cancer

Immunotherapy is a promising approach in an effort to control castration resistant prostate cancer. We characterized tumor antigen reactive T cells in patients with prostate cancer and analyzed the suppression of antitumor responses by regulatory T cells. Peripheral blood samples were collected from 57 patients with histologically confirmed prostate cancer, 8 patients with benign prostatic hyperplasia and 16 healthy donors. Peripheral blood mononuclear cells were isolated and antigen specific interferon-γ secretion of isolated T cells was analyzed by enzyme-linked immunospot assay. T cells were functionally characterized and T-cell responses before and after regulatory T-cell depletion were compared. As test tumor antigens, a panel of 11 long synthetic peptides derived from a total of 8 tumor antigens was used, including prostate specific antigen and prostatic acid phosphatase. In patients with prostate cancer we noted a 74.5% effector T-cell response rate compared with only 25% in patients with benign prostatic hyperplasia and 31% in healthy donors. In most patients 2 or 3 tumor antigens were recognized. Comparing various disease stages there was a clear increase in the immune response against prostate specific antigens from intermediate to high risk tumors and castration resistant disease. Regulatory T-cell depletion led to a significant boost in effector T-cell responses against prostate specific antigen and prostatic acid phosphatase. Tumor specific effector T cells were detected in most patients with prostate cancer, especially those with castration resistant prostate cancer. Since effector T-cell responses against prostate specific antigens strongly increased after regulatory T-cell depletion, our results indicate that immunotherapy efficacy could be enhanced by decreasing regulatory T cells.

Abstract 3650: In Vitro and in vivo synergistic anticancer effect of HDAC inhibitor panobinostat (LBH589) plus zoledronic acid in human prostate, breast and multiple myeloma tumor models

Abstract Prostate cancer (PCa), multiple myeloma (MM) as well as triple-negative breast cancers (TNBCa) (lacking ER, PR, and ErbB2 receptor) are associated with aggressive behaviour, poor prognosis, and limited response to conventional chemotherapy as well as to molecular targeted drugs, in advanced disease. On this regards, the recent availability of agents able to regulate many signaling pathways, such as HDAC inhibitors (HDAC-Is) as well as bisphosphonates (BPs), can help to overcome the existence limited activity of anticancer strategies. The HDAC-I Panobinostat (LBH589) has shown significant preclinical and clinical anticancer activity in both haematological and solid malignancies, and is currently in phase III for relapsed MM. BPs, such as zoledronic acid (ZOL), inhibit osteoclast-mediated bone resorption and are indicated for the treatment of cancer bone metastasis. In addition a direct and indirect anticancer activity of ZOL in several preclinical models and clinical studies have been observed. In our study, we sought to define preclinically, the potential anticancer effect of Panobinostat in combination with ZOL in several cell models. We showed a potent synergistic antiproliferative effect of Panobinostat/ZOL treatment in PC3, LNCAP and DU145 PCa cells, independently of p53/KRAS status as well as androgen dependency, whatever schedule of administration (simultaneous vs sequential) we used, as demonstrated by median drug effect analysis calculating combination index (CI) according to the method of Chou and Talalay (CI<1). Similar results were obtained in MM cells (RPMI and U266 and LP1, KMS12BM, KMS21BM). Moreover, consistent preliminary results showed sequence-dependent synergistic/additive effect in TNBCa cells. We also demonstrated that the combination of Panobinostat and ZOL, compared to single agents treatment, increased apoptotic cell death as demonstrated by Annexin V-FITC staining, and PARP cleavage, in both PCa and MM cells. The oxidative injury may play a functional role in the observed increase cell death, because co-administration of the antioxidant N-acetyl-L-cystein blocked reactive oxygen species generation and apoptosis. Furthermore, a synergistic inhibition of cancer cell migration and invasion in the combination setting compared to single drug treatment were observed. At the molecular level the observed anticancer synergistic effect could be, at least in part, related to the ability of Panobinostat to downregulate the activation of p38MAPK induced by ZOL, which has been described as a mechanism of resistance to aminoBPs treatment. The synergistic anticancer effect of Panobinostat/ZOL combination was confirmed in vivo in PCa DU145 cells xenograft model, where we observed a marked inhibition of tumor growth in the combination-treated group compared to controls and single agents treated group. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3650.

Megalin‐ and Disabled‐2‐mediated uptake of vitamin D‐binding protein is modulated by all‐trans‐retinoic acid in prostate and colon epithelial cells

Disabled‐2 (Dab2) is an adapter protein, that along with the membrane receptors megalin and cubilin, is essential for uptake of protein‐complexed 25‐hydroxycholecalciferol (25D3) in the kidney and maintenance of serum vitamin D homeostasis. Previously, we showed that mammary cells (T‐47D) also express Dab2, megalin, and cubilin and internalize vitamin D‐binding protein (DBP) by receptor‐mediated endocytosis. Moreover, induction of Dab2 and megalin by the differentiating agent all‐trans‐retinoic acid (RA) correlated with DBP uptake in mammary cells. These findings suggest that expression of Dab2, megalin, and cubilin are critical for the uptake and anti‐tumorigenic effects of vitamin D in cancer‐prone tissues. In this present study, we have extended our work by characterizing the uptake of DBP and the expression of Dab2 and megalin in prostate cancer (PC‐3 and LNCaP) and colon cancer (Caco‐2) cells. Our results indicate that Dab2 and megalin mRNA and protein are abundant in PC‐3, LNCaP, and Caco‐2 cell lines. This expression was markedly enhanced when treated with 10 μM RA. Furthermore, DBP was readily internalized by PC‐3, LNCaP, and Caco‐2 cells. Taken together, these are the first studies to our knowledge that have characterized a potential role for Dab2 and megalin in the uptake of vitamin D in prostate and colon cells. Supported by NIH SR03CA128091‐03 and Iowa State University Experiment station to MJR.

Clinical efficacy and safety of zoledronic acid in prostate and breast cancer

The anti-estrogen treatment for hormone-sensitive breast cancer and the androgen deprivation therapy for prostate cancer can lead to the development of osteoporosis and bone fractures. Metastases associated with prostate and breast cancer can also occur in bone. Bisphosphonates are used in these types of bone dysfunction. Zoledronic acid is the most potent bisphosphonate. In osteoporosis, zoledronic acid inhibits bone reabsorption and increases bone mineral density for at least a year after intravenous administration. The efficacy and safety of zoledronic acid in osteoporosis secondary to hormone-sensitive cancers (prostate and breast), and in the bone metastases associated with these cancers are reviewed.

Effect of α-Chlorohydrin on the Male Reproductive Organs of the Indian Langur: (Presbytis entellus entellus Dufresne)

A subtoxic dose of alpha-chlorohydrin (3-chloro-1, 2-propanediol, U-5897) was injected subcutaneously 10 mg/kg for 30 days into adult male langur monkeys (Presbytis). The animals did not lose weight; there was a reduction of weight of the testis and accessories. Histologically, spermatogenesis was suppressed but the interstitial cells appeared normal. In the caput epididymides, the diameter of the tubule was reduced by half as compared to the control and the height of cells was also reduced; in the cauda epididymidis, the cilia were either absent or reduced in size. Sialic acid concentration was reduced in the testis and epididymis of the treated animals; fructose in seminal vesicle and citric acid in prostate were also reduced though morphologically the interstitial cells looked normal, they were functionally anti-anabolic. This appears to be a new profile of alpha-chlorohydrin action in a primate.

Female sexual dysfunction after pelvic surgery: the impact of surgical modifications

The truly international authorship every month in the Journal is reflected in the Mini‐Review section in this issue. One from the USA, one from Canada, and two from Italy. It is a great pleasure to the Editor that this is so, and I hope also to the readership and to those who make such excellent contributions. The topics covered are female sexual dysfunction after pelvic surgery, zoledronic acid in prostate and renal cancers, intravesical gemcitabine for superficial bladder cancer, and the reduction of patient discomfort during TRUS‐guided biopsy of the prostate.

Lymph Node Metastases of Prostatic Adenocarcinoma in the Mesorectum in Patients With Adenocarcinoma or Villous Tumor of the Rectum With Collision Phenomenon in a Single Lymph Node: Report of Five Cases

Lymph node involvement is the most important prognostic factor when staging patients with rectal cancer. Cancer originating from sites other than rectum rarely may metastasize to the mesorectum. We report five patients with metastatic prostatic carcinoma to mesorectal lymph nodes, with the "collision phenomenon" in one lymph node. The diagnosis of prostate cancer was clinically unsuspected in two cases. We examined three cases of primary adenocarcinoma and two villous tumors with high-grade dysplasia (patient age range, 52-74 (mean, 63) years) of the middle or lower third of the rectum. All patients underwent low anterior rectal resection with total mesorectal excision and colorectal or coloanal anastomosis. We used a manual technique for lymph node detection after overnight fixation in 10 percent formalin. All lymph nodes identified (range, 15-32; mean, 21 nodes per patient) were examined histologically. Of 106 lymph nodes examined, 20 contained metastases: 9 from rectal adenocarcinoma, 10 from prostatic adenocarcinoma, and 1 with metastatic foci from both tumors. The diagnosis of prostatic carcinoma was readily confirmed by immunostaining for prostatic-specific antigen, and prostatic acid phosphatase. Mesorectal lymph node dissection provides prognostic information in rectal cancer, but careful examination may reveal other unsuspected pathology. Immunohistochemical staining is an essential tool in distinguishing the origin of a lymph node metastasis, especially when the histology does not look typical for rectal carcinoma. Moreover, these observations highlight the connection that can exist between mesorectal lymph node drainage, and extra mesorectal lymph nodes drainage.

Endocrine-disrupting agents on healthy human tissues.

A vast number of substances have been suggested as possibly contributing to perturbation of the endocrine system. Several have been tested with different approaches ranging from yeast expression system of human oestrogenic receptors to human breast cancer cells assays. Surprisingly, no inhibition-binding experiments to steroid receptors on healthy human tissue have been performed so far. Our study provides inhibition binding experiments to oestrogens, progesterone, testosterone and retinoic acid receptors in prostate and uterine human tissue of organochlorine pesticides, phthalate esters, oestrogenic constituents derived from plants and phenol derivates. Affinities of significant extent of phthalates on oestrogenic, progestinic and androgenic receptors have not been detected. As for retinoic acid receptors, mono(2-ethylexyl)phthalate provokes a notable reduction of the binding of the tritiated retinoic acid, phtalic acid ethyl-n-butyl ester and 4-octylphenol show an affinity comparable to that of isoflavonoid genistein, whereas 4-nonylphenol reduces the binding of retinoic acid in prostate.

Immunocytochemical localization of seminal proteins in salivary and lacrimal glands of the rat.

Antibodies against 10 different secretory proteins from the accessory sex glands of the male rat were used for immunohistochemical studies of salivary and lacrimal glands from intact and castrated rats, at the light- and electron-microscopic levels. In the parotid gland, secretory acinar cells showed immunoreactivity with antibodies against prostatic binding protein, cystatin-related peptide and acid phosphatase (isoenzyme pI 8.0; 5.6) typical of ventral prostate, and seminal vesicle secretion VI. Western blotting analysis indicated that immunoreactivity against prostatic binding protein was attributable to a subunit, presumably C3. Acid phosphatase pI 5.6 showed a molecular weight of 66 kDa, which is at variance with the prostatic form. Immunoreactivity for secretory transglutaminase, derived from the coagulating gland, was restricted to myoepithelial and stromal cells. In castrated animals, the immunoreactivity of acinar cells was reduced to the background level, whereas stromal transglutaminase immunoreactivity was unaltered. The distribution pattern of immunoreactivity for the proteins mentioned was almost identical in the lacrimal gland. Significant differences were however observed in the immunoreactivity of the inframandibular gland, where serous glandular cells were non-immunoreactive for seminal proteins, with the exception of acid phosphatase isoenzyme pI 8.0. Granules present in the convoluted granular ducts were immunoreactive particularly for acid phosphatase (isoenzyme pI 5.6) but much less for cystatin-related peptide; immunoreactivity was reduced after castration. The straight portion of the inframandibular duct system was immunoreactive for transglutaminase, but no influence of castration was visible. The distribution of immunoreactivity for seminal proteins present in the salivary and lacrimal glands and the pronounced androgen-dependence of their expression point to functional relationships of the respective proteins at both glandular sites.

Detection of seminal antibodies to human immunodeficiency virus in vaginal secretions after sexual intercourse: Possible means of preventing the risk of human immunodeficiency virus transmission in a rape victim

Detection of semen anti-human immunodeficiency virus (HIV) antibodies within the cervicovaginal secretions from a non-HIV-infected woman who has had a recent sexual intercourse with an HIV-infected man is theoretically possible since the seminal fluid from all HIV-infected men contains a high titer of IgG antibodies to HIV. We report the case of an HIV-seronegative African woman whose cervico-vaginal secretions contained IgG antibodies to HIV, including antibodies to HIV-env-encoded glycoproteins. This woman had also detectable prostatic specific antigens and acid phosphatase in her cervico-vaginal secretions, establishing the persistence of semen. In order to confirm whether anti-HIV antibodies in seminal fluid could be detected in vitro when mixed with cervico-vaginal secretions, 10(-1) to 10(-6) 10-fold dilutions of seminal fluid from HIV-1-seropositive donors were realized with a pool of HIV-negative cervico-vaginal secretions as diluent. Six commercial enzyme immunoassays or rapid tests were compared for semen anti-HIV detection in the secretions. At a 10(-1) dilution of the mixture, all assays were markedly positive for all tested semens and the greatest dilutions of seminal fluid showing positivity ranged from 10(-3) to 10(-5). The IgG immunocapture assay appeared to be the most sensitive test. The rapid tests permitted the detection of semen IgG antibodies to HIV at dilutions ranging from 10(-1) to 10(-3) suggesting their potential value in emergency situations.

Effect of ultrasound guided core biopsy of prostate on serum concentration of prostate specific antigen and acid phosphatase activity.

Forty-three patients had their serum concentrations of prostate specific antigen and activity of tartrate inhibited acid phosphatase measured before and after digital rectal examination, transrectal ultrasonography and transrectal core biopsy. Transrectal core biopsy significantly increased the values for both tumor markers but rectal examination and ultrasonography without biopsy had no such effect. The measurements returned to normal within one week of biopsy in all but four patients who still had slightly increased concentrations of prostate specific antigen. We recommend that the concentration of prostate specific antigen and activity of tartrate inhibited acid phosphatase are checked before biopsy of the prostate is carried on.

4-MAPC, a 5 alpha-reductase inhibitor, reduces rat ventral prostate weight, DNA, and prostatein concentrations.

Several compounds, such as 4-MAPC (4-methyl-3-oxo-4-aza-5 alpha-pregnane-20- carboxylate), that inhibit conversion of testosterone (T) to dihydrotestosterone (DHT) by 5 alpha-reductase have been demonstrated to reduce prostate size in rats and dogs. The current studies were undertaken to determine if this effect is due to a reduction in cell number, in epithelial cell synthetic activity, or both. Eight-week-old intact rats were treated daily for 14 days with sesame seed oil, 4-MAPC (10 mg/kg), 4-MAPC + testosterone propionate (TP, 1 mg/kg), or 4-MAPC + TP (3 mg/kg). Rats were killed 24 hours after the last injection. In the animals treated only with 4-MAPC, ventral prostate weight was reduced 37%, but the 14% reduction in total DNA was not significant. The mean intraprostatic concentration of prostatein, a major secretory protein, was reduced 45% (P less than 0.05). The 3 mg/kg dose of TP increased ventral prostate weight, prostatein concentrations, and acid phosphatase activity, even though DNA/ventral prostate was similar to that in control animals. These observations indicate that the reduction in ventral prostate weight in adult rats is due in part to a reduction in cell number, but the primary effect was due to a reduction in synthetic activity, and possibly atrophy of the epithelial cells. Furthermore, TP in pharmacologic doses increased ventral prostate weight and synthetic activity without increasing DNA.

Prostatakarzinom mit einer ungewöhnlichen Verlaufsform

The case of a 60 years old patient with peritoneal carcinomatosis of a tumor with small cell histology is reviewed. At presentation, biopsy of a rectal palpatory finding revealed a small cell carcinoma, infiltrating the mucosa. A laparotomy was done, which showed a grotesque peritoneal carcinomatosis of the same histology with masses retro- and infraperitoneally and in the pelvis. Clinically and histologically a probable epithelial peritoneal mesothelioma was diagnosed. The patient survived half a year only. Autopsy and post-mortem work-up demonstrated the presence of a small cell prostatic cancer, positive for both prostate specific antigen and acid phosphatase. A discussion of diagnostic procedures and differential diagnoses is given.

Prostate Specific Antigen and Acid Phosphatase-Reactive Cells in Cystitis Cystica and Glandularis

Cystitis cystica (CC) and cystitis glandularis (CG) are common in the urothelium lining the bladder neck and trigone. Because some cases of CG show histologic features strikingly similar to prostatic acini, we hypothesized that some such foci may represent prostatelike metaplasia in the urinary bladder. Forty surgical and autopsy bladder specimens (23 males, 17 females) showing CC or CG were studied using anti-prostate specific antigen and anti-prostate specific acid phosphatase antibodies. Fourteen (35%) of these 40 cases showed positive staining for prostate specific antigen or prostate specific acid phosphatase or both in CC or CG foci. Among these were five female patients. The findings indicate that bladder epithelium is capable of undergoing prostatelike metaplasia and lend support to the hypothesis that the adult bladder stroma closest to the prostate may exert inductive influences on the overlying epithelium to show prostatelike metaplasia.

Interaction of sex steroids and prolactin on phosphatases, transaminases, and citric acid in the ventral prostate of male albino rats.

The interaction of androgens, testosterone propionate (TP), and dihydrotestosterone (DHT) with prolactin (PRL) and estradiol-17 beta (E2) on phosphatases, transaminases, and citric acid were studied in the ventral prostate of prepubertal and adult intact and castrated rats. None of the secretory products studied were affected by androgens or their combinations with E2/PRL in prepubertal rats except for the increase observed in organ weight and DNA content. However, in adults the hormonal combinations produced some significant changes. Among the secretory products, phosphatases, glutamate oxaloacetic transaminase (GOT), and citric acid increased significantly in adult rats after the administration of TP/DHT. Glutamate pyruvic transaminase (GPT) required PRL along with TP/DHT to show an appreciable increment in intact adult rats. The synergistic effect of PRL with androgens was observed in the adult ventral prostatic secretory acid phosphatase and citric acid. Unlike PRL, E2 in combination with androgens produced an antagonistic effect in intact adult rats, which was well pronounced in the case of prostatic weight, DNA content secretory acid phosphatase, and citric acid. None of the androgens or their combination with PRL produced any significant change in DNA content compared to intact controls.

The Influence of Androgen—Receptor Complexes on Transcription by Rat and Human Prostatic Ribonucleic Acid Polymerases

s of Communications Meeting of the Biochemical Society Steroid Group held at Imperial College, London, 1 July 1975 HORMONAL. REGULATION OF MACROMOLECULAR SYNTHESES : a Colloquium organized by W. I. P. Mainwaring (London) The Influence of Androgen-Receptor Complexes on Transcription by Rat and Human Prostatic Ribonucleic Acid Polymerases PETER DAVIES Tenovus Institute for Cancer Research, Welsh National School of Medicine, Heath Park, Cardifs CF4 4XX, U.K. The many changes in cellular components that occur in a sensitive tissue in response to hormonal stimulation are largely secondary to the key molecular step at the genomic or transcriptional level, resulting in an enhancement of RNA synthesis (Williams-Ashman & Reddi, 1971 ; Jensen & DeSombre, 1972). The eukaryotic transcriptional machinery involves acomplexity of functional, structural and regulatory macromolecules, and RNA synthesis may be controlled at the level of chromatin template activity and activity, RNA polymerase activity, biosynthesis and pool size of RNA precursors or RNA processing and maturation. Androgenic influences in the rat ventral prostate gland are mediated by the metabolism of testosterone to 5a-dihydrotestosterone, the binding of this latter compound to proteins of selective high affinity and the transfer of the complex thus formed to nuclear acceptor sites with steroid and tissue specificity [see review by Minguell & Sierralta (1975)l. Previous investigations using reconstituted cell-free systems based on nuclei or on chromatin transcribed by purified prostatic RNA polymerases have shown that 5a-dihydrotestosterone-receptor complexes prepared from subcellular fractions of rat ventral prostate have significant stimulatory effects on the activities of discrete RNA polymerases from the same source (Davies & Griffiths, 1973a,b; 1974a,b). Studies on transcription of chromatin by solubilized RNA polymerases have shown that for stimulation to occur the steroid-receptor complex, rather than the steroid or receptor protein alone, must be present together with prostatic chromatin rather than chromatin from non-target tissues or naked DNA, the chromatin specificity depending on the presence of a small proportion of non-histone proteins tightly bound to the DNA (Davies & Griffiths, 1973a,b). The abilities of the specific cytoplasmic and nuclear steroid-receptor complexes to stimulate RNA polymerase activity to equivalent extents have been attributed to the ‘activation’ of the cytoplasmic form in the assay medium, causing it to undergo a temperature-dependent conversion into a form similar to that of the complex extractable from nuclear preparations (Davies & Griffiths, 1974b). Recent studies have indicated that the macromolecules specifically binding 5adihydrotestosterone in rat ventral prostate and human benign hypertrophic prostate have similar properties and that the cytoplasmic receptor complexes in each case may transfer the steroid to homologous or heterologous nuclear fractions of androgenVOl. 3