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Rzeszotek S, Kolasa A, Pilutin A, Misiakiewicz-Has K, Sielatycka K, Wiszniewska B. The Interplay between Finasteride-Induced Androgen Imbalance, Endoplasmic Reticulum Stress, Oxidative Stress, and Liver Disorders in Paternal and Filial Generation. Biomedicines 2022; 10:2725. [PMID: 36359245 PMCID: PMC9687381 DOI: 10.3390/biomedicines10112725] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 10/20/2023] Open
Abstract
Finasteride (Fin) causes androgen imbalance by inhibiting the conversion of testosterone (T) to its more active metabolite, dihydrotestosterone (DHT). Androgen receptors (AR) are present (e.g., in hepatocytes), which have well-developed endoplasmic reticulum (ERet). Cellular protein quality control is carried out by ERet in two paths: (i) unfolded protein response (UPR) and/or (ii) endoplasmic reticulum associated degradation (ERAD). ERet under continuous stress can generate changes in the UPR and can direct the cell on the pathway of life or death. It has been demonstrated that genes involved in ERet stress are among the genes controlled by androgens in some tissues. Oxidative stress is also one of the factors affecting the functions of ERet and androgens are one of the regulators of antioxidant enzyme activity. In this paper, we discuss/analyze a possible relationship between androgen imbalance in paternal generation with ERet stress and liver disorders in both paternal and filial generation. In our rat model, hyperglycemia and subsequent higher accumulation of hepatic glycogen were observed in all filial generation obtained from females fertilized by Fin-treated males (F1:Fin). Importantly, genes encoding enzymes involved in glucose and glycogen metabolism have been previously recognized among UPR targets.
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Affiliation(s)
- Sylwia Rzeszotek
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Agnieszka Kolasa
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Anna Pilutin
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Kamila Misiakiewicz-Has
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
| | - Katarzyna Sielatycka
- Institute of Biology, Faculty of Exact and Natural Sciences, University of Szczecin, 71-415 Szczecin, Poland
| | - Barbara Wiszniewska
- Department of Histology and Embryology, Pomeranian Medical University in Szczecin, 70-111 Szczecin, Poland
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Novel Nine-Exon AR Transcripts (Exon 1/Exon 1b/Exons 2-8) in Normal and Cancerous Breast and Prostate Cells. Int J Mol Sci 2016; 18:ijms18010040. [PMID: 28035996 PMCID: PMC5297675 DOI: 10.3390/ijms18010040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 12/12/2022] Open
Abstract
Nearly 20 different transcripts of the human androgen receptor (AR) are reported with two currently listed as Refseq isoforms in the NCBI database. Isoform 1 encodes wild-type AR (type 1 AR) and isoform 2 encodes the variant AR45 (type 2 AR). Both variants contain eight exons: they share common exons 2-8 but differ in exon 1 with the canonical exon 1 in isoform 1 and the variant exon 1b in isoform 2. Splicing of exon 1 or exon 1b is reported to be mutually exclusive. In this study, we identified a novel exon 1b (1b/TAG) that contains an additional TAG trinucleotide upstream of exon 1b. Moreover, we identified AR transcripts in both normal and cancerous breast and prostate cells that contained either exon 1b or 1b/TAG spliced between the canonical exon 1 and exon 2, generating nine-exon AR transcripts that we have named isoforms 3a and 3b. The proteins encoded by these new AR variants could regulate androgen-responsive reporters in breast and prostate cancer cells under androgen-depleted conditions. Analysis of type 3 AR-GFP fusion proteins showed partial nuclear localization in PC3 cells under androgen-depleted conditions, supporting androgen-independent activation of the AR. Type 3 AR proteins inhibited androgen-induced growth of LNCaP cells. Microarray analysis identified a small set of type 3a AR target genes in LNCaP cells, including genes known to modulate growth and proliferation of prostate cancer (PCGEM1, PEG3, EPHA3, and EFNB2) or other types of human cancers (TOX3, ST8SIA4, and SLITRK3), and genes that are diagnostic/prognostic biomarkers of prostate cancer (GRINA3, and BCHE).
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Kärst S, Arends D, Heise S, Trost J, Yaspo ML, Amstislavskiy V, Risch T, Lehrach H, Brockmann GA. The direction of cross affects [corrected] obesity after puberty in male but not female offspring. BMC Genomics 2015; 16:904. [PMID: 26546267 PMCID: PMC4636810 DOI: 10.1186/s12864-015-2164-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 10/29/2015] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND We investigated parent-of-origin and allele-specific expression effects on obesity and hepatic gene expression in reciprocal crosses between the Berlin Fat Mouse Inbred line (BFMI) and C57Bl/6NCrl (B6N). RESULTS We found that F1-males with a BFMI mother developed 1.8 times more fat mass on a high fat diet at 10 weeks than F1-males of a BFMI father. The phenotype was detectable from six weeks on and was preserved after cross-fostering. RNA-seq data of liver provided evidence for higher biosynthesis and elongation of fatty acids (p = 0.00635) in obese male offspring of a BFMI mother versus lean offspring of a BFMI father. Furthermore, fatty acid degradation (p = 0.00198) and the peroxisome pathway were impaired (p = 0.00094). The circadian rhythm was affected as well (p = 0.00087). Among the highest up-regulated protein coding genes in obese males were Acot4 (1.82 fold, p = 0.022), Cyp4a10 (1.35 fold, p = 0.026) and Cyp4a14 (1.32 fold, p = 0.012), which hydroxylize fatty acids and which are known to be increased in liver steatosis. Obese males showed lower expression of the genetically imprinted and paternally expressed 3 (Peg3) gene (0.31 fold, p = 0.046) and higher expression of the androgen receptor (Ar) gene (2.38 fold, p = 0.068). Allelic imbalance was found for expression of ATP-binding cassette transporter gene Abca8b. Several of the differentially expressed genes contain estrogen response elements. CONCLUSIONS Parent-of-origin effects during gametogenesis and/or fetal development in an obese mother epigenetically modify the transcription of genes that lead to enhanced fatty acid synthesis and impair β-oxidation in the liver of male, but not female F1 offspring. Down-regulation of Peg3 could contribute to trigger this metabolic setting. At puberty, higher amounts of the androgen receptor and altered access to estrogen response elements in affected genes are likely responsible for male specific expression of genes that were epigenetically triggered. A suggestive lack of estrogen binding motifs was found for highly down-regulated genes in adult hepatocytes of obese F1 males (p = 0.074).
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Affiliation(s)
- Stefan Kärst
- Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften, Humboldt-Universität zu Berlin, Invalidenstraße 42, D-10115, Berlin, Germany
| | - Danny Arends
- Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften, Humboldt-Universität zu Berlin, Invalidenstraße 42, D-10115, Berlin, Germany
| | - Sebastian Heise
- Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften, Humboldt-Universität zu Berlin, Invalidenstraße 42, D-10115, Berlin, Germany
| | - Jan Trost
- Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften, Humboldt-Universität zu Berlin, Invalidenstraße 42, D-10115, Berlin, Germany
| | - Marie-Laure Yaspo
- Max Planck Institute for Molecular Genetics, Gene Regulation and Systems Biology of Cancer, Ihnestraße 63-73, 14195, Berlin, Germany
| | - Vyacheslav Amstislavskiy
- Max Planck Institute for Molecular Genetics, Gene Regulation and Systems Biology of Cancer, Ihnestraße 63-73, 14195, Berlin, Germany
| | - Thomas Risch
- Max Planck Institute for Molecular Genetics, Gene Regulation and Systems Biology of Cancer, Ihnestraße 63-73, 14195, Berlin, Germany
| | - Hans Lehrach
- Max Planck Institute for Molecular Genetics, Gene Regulation and Systems Biology of Cancer, Ihnestraße 63-73, 14195, Berlin, Germany
| | - Gudrun A Brockmann
- Albrecht Daniel Thaer-Institut für Agrar- und Gartenbauwissenschaften, Humboldt-Universität zu Berlin, Invalidenstraße 42, D-10115, Berlin, Germany.
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Ribarska T, Goering W, Droop J, Bastian KM, Ingenwerth M, Schulz WA. Deregulation of an imprinted gene network in prostate cancer. Epigenetics 2014; 9:704-17. [PMID: 24513574 DOI: 10.4161/epi.28006] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Multiple epigenetic alterations contribute to prostate cancer progression by deregulating gene expression. Epigenetic mechanisms, especially differential DNA methylation at imprinting control regions (termed DMRs), normally ensure the exclusive expression of imprinted genes from one specific parental allele. We therefore wondered to which extent imprinted genes become deregulated in prostate cancer and, if so, whether deregulation is due to altered DNA methylation at DMRs. Therefore, we selected presumptive deregulated imprinted genes from a previously conducted in silico analysis and from the literature and analyzed their expression in prostate cancer tissues by qRT-PCR. We found significantly diminished expression of PLAGL1/ZAC1, MEG3, NDN, CDKN1C, IGF2, and H19, while LIT1 was significantly overexpressed. The PPP1R9A gene, which is imprinted in selected tissues only, was strongly overexpressed, but was expressed biallelically in benign and cancerous prostatic tissues. Expression of many of these genes was strongly correlated, suggesting co-regulation, as in an imprinted gene network (IGN) reported in mice. Deregulation of the network genes also correlated with EZH2 and HOXC6 overexpression. Pyrosequencing analysis of all relevant DMRs revealed generally stable DNA methylation between benign and cancerous prostatic tissues, but frequent hypo- and hyper-methylation was observed at the H19 DMR in both benign and cancerous tissues. Re-expression of the ZAC1 transcription factor induced H19, CDKN1C and IGF2, supporting its function as a nodal regulator of the IGN. Our results indicate that a group of imprinted genes are coordinately deregulated in prostate cancers, independently of DNA methylation changes.
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Affiliation(s)
- Teodora Ribarska
- Department of Urology; Heinrich Heine University; Düsseldorf, Germany
| | - Wolfgang Goering
- Department of Urology; Heinrich Heine University; Düsseldorf, Germany
| | - Johanna Droop
- Department of Urology; Heinrich Heine University; Düsseldorf, Germany
| | | | - Marc Ingenwerth
- Department of Urology; Heinrich Heine University; Düsseldorf, Germany; Institute for Anatomy II; Heinrich Heine University; Düsseldorf, Germany
| | - Wolfgang A Schulz
- Department of Urology; Heinrich Heine University; Düsseldorf, Germany
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Maternal high-fat diet induces hyperproliferation and alters Pten/Akt signaling in prostates of offspring. Sci Rep 2013; 3:3466. [PMID: 24322661 PMCID: PMC3857567 DOI: 10.1038/srep03466] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 11/25/2013] [Indexed: 11/08/2022] Open
Abstract
Developing recommendations for prostate cancer prevention requires identification of modifiable risk factors. Maternal exposure to high-fat diet (HFD) initiates a broad array of second-generation adult disorders in murine models and humans. Here, we investigate whether maternal HFD in mice affects incidence of prostate hyperplasia in offspring. Using three independent assays, we demonstrate that maternal HFD is sufficient to initiate prostate hyperproliferation in adult male offspring. HFD-exposed prostate tissues do not increase in size, but instead concomitantly up-regulate apoptosis. Maternal HFD-induced phenotypes are focally present in young adult subjects and greatly exacerbated in aged subjects. HFD-exposed prostate tissues additionally exhibit increased levels of activated Akt and deactivated Pten. Taken together, we conclude that maternal HFD diet is a candidate modifiable risk factor for prostate cancer initiation in later life.
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Specific changes in the expression of imprinted genes in prostate cancer--implications for cancer progression and epigenetic regulation. Asian J Androl 2012; 14:436-50. [PMID: 22367183 DOI: 10.1038/aja.2011.160] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Epigenetic dysregulation comprising DNA hypermethylation and hypomethylation, enhancer of zeste homologue 2 (EZH2) overexpression and altered patterns of histone modifications is associated with the progression of prostate cancer. DNA methylation, EZH2 and histone modifications also ensure the parental-specific monoallelic expression of at least 62 imprinted genes. Although it is therefore tempting to speculate that epigenetic dysregulation may extend to imprinted genes, expression changes in cancerous prostates are only well documented for insulin-like growth factor 2 (IGF2). A literature and database survey on imprinted genes in prostate cancer suggests that the expression of most imprinted genes remains unchanged despite global disturbances in epigenetic mechanisms. Instead, selective genetic and epigenetic changes appear to lead to the inactivation of a sub-network of imprinted genes, which might function in the prostate to limit cell growth induced via the PI3K/Akt pathway, modulate androgen responses and regulate differentiation. Whereas dysregulation of IGF2 may constitute an early change in prostate carcinogenesis, inactivation of this imprinted gene network is rather associated with cancer progression.
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Dowdy SC, Gostout BS, Shridhar V, Wu X, Smith DI, Podratz KC, Jiang SW. Biallelic methylation and silencing of paternally expressed gene 3 (PEG3) in gynecologic cancer cell lines. Gynecol Oncol 2005; 99:126-34. [PMID: 16023706 DOI: 10.1016/j.ygyno.2005.05.036] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 05/17/2005] [Accepted: 05/20/2005] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To measure mRNA expression levels of paternally expressed gene 3 (PEG3) in gynecologic cancer cell lines and to determine if DNA methylation is involved in the control of PEG3 expression. METHODS PEG3 mRNA levels were measured with real-time PCR from 28 gynecologic cancer cell lines and compared to normal tissues. PEG3 mRNA expression was correlated to promoter methylation levels measured by real-time methylation-specific PCR. Polymorphism-specific restriction digestion was employed to analyze PEG3 allele distribution. RESULTS While expressed in normal gynecologic tissues, PEG3 is silenced in all endometrial and cervical cancer cell lines studied. In the eight ovarian cancer cell lines, five were found to be PEG3 negative, the remaining three express low levels of PEG3 mRNA. In contrast, loss of maternal imprinting and relatively high PEG3 expression levels were detected in all four choriocarcinomas cell lines studied. No cell line confirmed to contain two copies of PEG3 expressed PEG3 mRNA, suggesting that PEG3 downregulation is not due to genetic deletion. PEG3 mRNA expression was, however, quantitatively correlated to its promoter methylation status. Treatment of PEG3 negative cells with DNA methyltransferase inhibitor 5'-aza-deoxycytidine led to partial promoter demethylation and biallelic reactivation of PEG3 transcription, confirming the methylation-mediated mechanism for PEG3 silencing. CONCLUSION PEG3 silencing is associated with DNA hypermethylation but not gene deletion in cell lines tested. These results suggest that loss of PEG3 expression may be a frequent event in gynecologic cancers. Given the known role of PEG3 in p53-mediated apoptosis, it is possible that PEG3 functions as a tumor suppressor.
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Affiliation(s)
- Sean C Dowdy
- Department of Obstetrics and Gynecology, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55905, USA
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Suy S, Mitchell JB, Samuni A, Mueller S, Kasid U. Nitroxide tempo, a small molecule, induces apoptosis in prostate carcinoma cells and suppresses tumor growth in athymic mice. Cancer 2005; 103:1302-13. [PMID: 15685617 DOI: 10.1002/cncr.20898] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND In previous studies, nitroxide tempo (2, 2, 6, 6-tetramethyl-piperidine-1-oxyl), a small molecule, induced cell death in cancer cells. The current study examined the antineoplastic properties of tempo in the human hormone-dependent/hormone-independent prostate carcinoma models (LNCaP, DU-145, and PC-3). METHODS The apoptotic effects of tempo were examined by the flow cytometric analysis of cells labeled with fluorescein isothiocyanate-conjugated annexin-V, and by electron microscopy. Enzymatic assays were performed to measure the activities of 2 cysteine proteases, i.e., caspase-9 and caspase-3, in tempo-treated cells. The effects of tempo on cell proliferation and on cell cycle distribution profiles were measured by the flow cytometric assay using immunofluorescent staining of incorporated 5'-bromo-2'-deoxyuridine (BrdU) coupled with 7-amino-actinomycin D (7-AAD) staining of total DNA. The number of proliferating cells was also determined independently by enzyme-linked immunosorbent assay using chemiluminescent detection of incorporated BrdU. Subcutaneous growth of human prostate carcinoma in athymic mice was monitored after intratumoral administration of tempo into tumor-bearing mice. In addition, cell viability assays were performed to compare the cytotoxic effect of a combination of doxorubicin or mitoxantrone and tempo with single agents. RESULTS Tempo treatment of prostate carcinoma cells caused a significant increase in the number of apoptotic cells compared with control groups (tempo, 2.5 mM, 24 hours: DU-145, approximately 3.4-fold; PC-3, approximately 6-7-fold; tempo 1 mM, 24 hours: LNCaP, approximately 12-fold). Tempo-induced loss of cell viability was blocked partially or completely after pretreatment of cells with actinomycin-D or cycloheximide, suggesting a de novo macromolecule synthesis-dependent mechanism of cell death. Electron microscopy revealed aggregation and marginalization of chromatin in the nuclei of a large number of tempo-treated LNCaP cells. Tempo treatment of LNCaP cells resulted in enhanced activities of caspase-9 (tempo, 5 mM, 15 hours: approximately 2-fold) and caspase-3 (tempo, 2.5 mM, 24 hours: approximately 12-fold). Tempo treatment also led to an enhanced number of cells in G2/M phase of the cell cycle (tempo, 5.0 mM, 24 hours: DU-145, approximately 1.6-fold; PC-3, approximately 1.5-fold; LNCaP, approximately 5.3-fold), and decreased BrdU incorporation indicative of a decline in the number of proliferating cells (tempo, 2.5 mM, 24 or 48 hours; DU-145, approximately 2-3-fold; PC-3, approximately 1.2-fold; LNCaP, approximately 5-10-fold). Administration of tempo into LNCaP tumor-bearing mice resulted in a significant inhibition of tumor growth (percent initial tumor volume [Day 30, n = 4]: vehicle, 845.35 +/- 272.83; tempo, 9.72 +/- 9.72; tempo vs. vehicle, P < 0.02). In hormone-refractory prostate carcinoma cells, a combination of relatively low doses of tempo and doxorubicin or mitoxantrone caused enhanced cytotoxicity as compared with single agents. CONCLUSIONS These data demonstrated that nitroxide tempo induced apoptosis and activated a caspase-mediated signaling pathway in prostate carcinoma cells. Tempo treatment also caused cell cycle arrest in G2/M phase and decreased the number of proliferating cells (S phase). Tempo treatment of tumor-bearing mice led to inhibition of tumor growth, suggesting that tempo is a novel member of the small-molecule family of antineoplastic agents.
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Affiliation(s)
- Simeng Suy
- Department of Radiation Medicine, Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
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Eder IE, Haag P, Basik M, Mousses S, Bektic J, Bartsch G, Klocker H. Gene expression changes following androgen receptor elimination in LNCaP prostate cancer cells. Mol Carcinog 2003; 37:181-91. [PMID: 12891627 DOI: 10.1002/mc.10136] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have shown recently that inhibition of androgen receptor (AR) expression with an antisense AR oligonucleotide (ODN) inhibits LNCaP prostate tumor cells in vitro as well as in vivo. In this study, we investigated gene expression changes that occur after AR signaling blockade, either through AR elimination by antisense treatment or through complete androgen receptor inhibition by androgen deprivation combined with the antiandrogen bicalutamide, in order to search for genes that are directly or indirectly regulated through the AR. Gene expression changes were investigated with cDNA NIH 10K gene microarrays in response to treatment over 48 h. Expression of selected genes was further analyzed by real-time reverse transcriptase (RT)-polymerase chain reaction (PCR), Western blotting, and radioimmunoassay. A comparison of antisense-treated and androgen-deprived cells revealed several concordances such as significant downregulation of prostate-specific genes, cell-cycle regulatory genes, genes of the cholesterol biosynthesis pathway, and several cytoskeletal genes. However, there were also several genes that were differentially regulated. Among the genes that were exclusively changed by treatment with the antisense AR ODN were the insulin-like growth factor binding protein 2 (IGFBP2) and the phosphatidylinositol-4-phosphate 5-kinase type I alpha (PIP5KIA). On the other hand, complete androgen receptor blockade induced changes in the expression of the prostate overexpressed gene 1 and the S100 calcium binding protein P. In summary, we identified a cohort of interesting genes whose expression was highly affected by elimination of the AR in LNCaP prostate cancer cells. Further investigations are warranted to clarify their role in the AR signaling pathway and their susceptibility as a target for the treatment of prostate cancer.
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Affiliation(s)
- Iris E Eder
- Department of Urology, University of Innsbruck, Innsbruck, Austria
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Qi H, Labrie Y, Grenier J, Fournier A, Fillion C, Labrie C. Androgens induce expression of SPAK, a STE20/SPS1-related kinase, in LNCaP human prostate cancer cells. Mol Cell Endocrinol 2001; 182:181-92. [PMID: 11514053 DOI: 10.1016/s0303-7207(01)00560-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Genes that are regulated by androgens in the human prostate are believed to play an essential role in prostate physiology and they may also be involved in the proliferative response of prostate cancer cells to androgens. We used a cDNA subtraction approach to identify novel androgen-regulated transcripts in LNCaP cells that were exposed to 0.1 nM R1881 for 24 h. We report here that SPAK, a recently identified STE20/SPS1-related kinase that modulates p38 MAP kinase activity, exhibited increased expression in androgen-treated LNCaP cells. Androgen regulation of SPAK was both dose- and time-dependent. R1881-induced SPAK expression was completely abrogated by the antiandrogen casodex and by actinomycin D indicating that androgen induction of SPAK requires the androgen receptor and transcription. Cycloheximide caused a partial inhibition of R1881-induced SPAK expression which suggests that androgen induction of SPAK expression may require synthesis of additional proteins. Northern blot and ribonuclease protection assays demonstrated that SPAK is expressed at high levels in normal human testes and prostate, as well as in a number of breast and prostate cancer cell lines. These results identify SPAK, a member of a key cell signalling pathway, as an androgen-responsive gene in LNCaP cells. We hypothesize that SPAK may mediate androgen action in the normal and cancerous prostate gland.
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Affiliation(s)
- H Qi
- Oncology and Molecular Endocrinology Research Center, CHUL Research Center (CHUQ), Laval University, Quebec, Canada G1V 4G2
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