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Biomedical subjects

Donna M Peehl

Publications and source records attributed to Donna M Peehl.

At least 37 records · Page 2Linked to original sources
PubMed2004

Mechanisms of decreased Vitamin D 1alpha-hydroxylase activity in prostate cancer cells.

Vitamin D 1alpha-hydroxylase (1alpha(OH)ase), which converts the circulating prohormone 25-hydroxyvitamin-D(3) (25(OH)D(3)) to the active 1alpha-25-dihydroxyvitamin-D(3) (1,25(OH)(2)D(3)), is present in normal prostatic epithelium. However, prostate cancer cells, both primary cultured cells and cell lines, have greatly decreased activity of 1alpha(OH)ase and are therefore resistant to the tumor suppressor activity of circulating 25(OH)D(3). We quantitated 1alpha(OH)ase mRNA and protein levels to investigate mechanism(s) responsible for decreased 1alpha(OH)ase enzymatic activity in prostate cancer. Prostate cancer cell lines had low 1alpha(OH)ase mRNA levels. Primary prostate cell cultures derived from normal and cancer tissues had equivalent levels of 1alpha(OH)ase RNA and protein. Equivalent 1alpha(OH)ase protein levels were observed in prostate tissue sections containing normal and malignant cells. The protein levels of hsc70, whose homolog intracellular Vitamin D binding protein (IDBP-1) facilitates delivery of 25(OH)D(3) to 1alpha(OH)ase in monkey cells, were equivalent in the normal and cancer cells. Equivalent activity in normal and cancer cells of Vitamin D 24-hydroxylase, a mitochondrial enzyme that also uses 25(OH)D(3) as a substrate, further ruled out lack of access to substrate as a basis for low activity of 1alpha(OH)ase in cancer cells. We conclude that diminished 1alpha(OH)ase activity in prostate cancer cell lines is through decreased gene expression, whereas decreased activity in primary cultures and tissues is post-translational.

Biological Transport↗
PubMed2004

Analysis of vitamin D-regulated gene expression in LNCaP human prostate cancer cells using cDNA microarrays.

BACKGROUND: 1,25-dihydroxyvitamin D(3) [1,25(OH)2D3] exerts growth inhibitory, pro-differentiating, and pro-apoptotic effects on prostate cells. To better understand the molecular mechanisms underlying these actions, we employed cDNA microarrays to study 1,25(OH)2D3-regulated gene expression in the LNCaP human prostate cancer cells. METHODS: mRNA isolated from LNCaP cells treated with vehicle or 50 nM 1,25(OH)2D3 for various lengths of time were hybridized to microarrays carrying approximately 23,000 genes. Some of the putative target genes revealed by the microarray analysis were verified by real-time PCR assays. RESULTS: 1,25(OH)2D3 most substantially increased the expression of the insulin-like growth factor binding protein-3 (IGFBP-3) gene. Our analysis also revealed several novel 1,25(OH)2D3-responsive genes. Interestingly, some of the key genes regulated by 1,25(OH)2D3 are also androgen-responsive genes. 1,25(OH)2D3 also down-regulated genes that mediate androgen catabolism. CONCLUSIONS: The putative 1,25(OH)2D3 target genes appear to be involved in a variety of cellular functions including growth regulation, differentiation, membrane transport, cell-cell and cell-matrix interactions, DNA repair, and inhibition of metastasis. The up-regulation of IGFBP-3 gene has been shown to be crucial in 1,25(OH)2D3-mediated inhibition of LNCaP cell growth. 1,25(OH)2D3 regulation of androgen-responsive genes as well as genes involved in androgen catabolism suggests that there are interactions between 1,25(OH)2D3 and androgen signaling pathways in LNCaP cells. Further studies on the role of these genes and others in mediating the anti-cancer effects of 1,25(OH)2D3 may lead to better approaches to the prevention and treatment of prostate cancer.

Biological Transport↗
PubMed2004

Are primary cultures realistic models of prostate cancer?

Primary cultures fill a unique niche among the repertoire of in vitro model systems available to investigate the biology of the normal and malignant human prostate. This review summarizes some of the properties of primary cultures, with special emphasis on two questions: are primary cultures from adenocarcinomas really comprised of cancer rather than normal cells, and do primary cultures faithfully retain characteristics of cells of origin?

Animals↗
PubMed2004

Epigenetic repression of transcription by the Vitamin D3 receptor in prostate cancer cells.

Normal prostate epithelial cells are acutely sensitive to the antiproliferative action of 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)), whilst prostate cancer cell lines and primary cultures display a range of sensitivities. We hypothesised that key antiproliferative target genes of the Vitamin D receptor (VDR) were repressed by an epigenetic mechanism in 1alpha,25(OH)(2)D(3)-insensitive cells. Supportively, we found elevated nuclear receptor co-repressor and reduced VDR expression correlated with reduced sensitivity to the antiproliferative action of 1alpha,25(OH)(2)D(3). Furthermore, the growth suppressive actions of 1alpha,25(OH)(2)D(3) can be restored by co-treatment with low doses of histone deacetylation inhibitors, such as trichostatin A (TSA) to induce apoptosis. Examination of the regulation of VDR target genes revealed that co-treatment of 1alpha,25(OH)(2)D(3) plus TSA co-operatively upregulated GADD45alpha. Similarly in a primary cancer cell culture, the regulation of appeared GADD45alpha repressed. These data demonstrate that prostate cancer cells utilise a mechanism involving deacetylation to suppress the responsiveness of VDR target genes and thus ablate the antiproliferative action of 1alpha,25(OH)(2)D(3).

Acetyltransferases↗
PubMed2004

Molecular activity of 1,25-dihydroxyvitamin D3 in primary cultures of human prostatic epithelial cells revealed by cDNA microarray analysis.

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] exerts anti-proliferative, differentiating and apoptotic effects on prostatic cells. These activities, in addition to epidemiologic findings that link Vitamin D to prostate cancer risk, support the use of 1,25(OH)(2)D(3) for prevention or therapy of prostate cancer. The molecular mechanisms by which 1,25(OH)(2)D(3) exerts antitumor effects on prostatic cells are not well-defined. In addition, there is heterogeneity among the responses of various prostate cell lines and primary cultures to 1,25(OH)(2)D(3) with regard to growth inhibition, differentiation and apoptosis. To understand the basis of these differential responses and to develop a better model of Vitamin D action in the prostate, we performed cDNA microarray analyses of primary cultures of normal and malignant human prostatic epithelial cells, treated with 50 nM of 1,25(OH)(2)D(3) for 6 and 24 h. CYP24 (25-hydroxyvitamin D(3)-24-hydroxylase) was the most highly upregulated gene. Significant and early upregulation of dual specificity phosphatase 10 (DUSP10), validated in five additional primary cultures, points to inhibition of members of the mitogen-activated protein kinase (MAPK) superfamily as a key event mediating activity of 1,25(OH)(2)D(3) in prostatic epithelial cells. The functions of other regulated genes suggest protection by 1,25(OH)(2)D(3) from oxidative stress. Overall, these results provide new insights into the molecular basis of antitumor activities of Vitamin D in prostate cells.

Calcitriol↗
PubMed2004

Molecular and cellular pathogenesis of benign prostatic hyperplasia.

PURPOSE: Symptomatic benign prostatic hyperplasia (BPH) is one of the most common ailments seen by the urologist. Significant advances have occurred in medical and surgical therapy, and in the understanding of the biology of this disease. However, the basic science literature is often conflicting and confusing, without a unified voice. We report the current state of knowledge of the molecular and cellular basis of BPH. MATERIALS AND METHODS: We compiled and interpreted basic science studies relevant to BPH pathogenesis. RESULTS: Cellular alterations that include changes in proliferation, differentiation, apoptosis and senescence in the epithelium and stroma are implicated in BPH pathogenesis. Molecular analyses have yielded numerous candidate genes important in disease progression. Differential expression of cytokines and growth factors in BPH tissue suggests roles for inflammation and hypoxia. Through the use of cell culture models the complex regulatory mechanisms of growth control in BPH are becoming defined. CONCLUSIONS: The scientific endeavor has resulted in great strides in our understanding of BPH on a molecular and cellular level. It is hopeful that basic science and translational research will improve treatment and prevention strategies for this common disease of elderly men.

Apoptosis↗
PubMed2003

Novel stimulatory role for insulin-like growth factor binding protein-2 in prostate cancer cells.

The insulin-like growth factor (IGF) axis is a complex system composed of 2 mitogenic ligands, IGF-I and -II, 2 receptors, IGF-1R and IGF-2R, and 6 binding proteins, IGFBP-1 to -6. The IGFBPs exert their actions through their regulation of IGF bioavailability for IGF receptors. In addition, some IGFBPs have also been found to have direct cellular actions independent of IGFs. IGFBP-2 is a major IGFBP in the prostate and in seminal fluid. IGFBP-2 levels, which are elevated in many malignancies, are markedly increased in prostate cancer, and show a positive correlation with prostate specific antigen (PSA) and prostate tumor aggressiveness. We investigated the potential role of IGFBP-2 in the pathogenesis of prostate cancer by evaluating its ability to stimulate growth and the expression and activity of the nuclear enzyme, telomerase. We found IGFBP-2 to have a modest suppressive effect on the growth of primary cultures of normal prostate epithelial cells and a potent IGF-antagonistic effect in these cells, similar to previous reports on the inhibitory nature of this molecule. Surprisingly, IGFBP-2 had a potent stimulatory effect on growth of LAPC-4 prostate cancer cells, an effect that was more pronounced in the absence of androgens. IGFBP-2 growth stimulation of LAPC-4 cells was completely blocked by MAP-kinase inhibitors and partially blocked by PI3-kinase inhibitors. IGFBP-2 stimulation of LAPC-4 cell growth seen in serum-free conditions was lost in the presence of 10% FBS. IGFBP-2 also had a growth stimulatory effect on DU 145 prostate cancer cells. IGFBP-2 significantly stimulated telomerase activity in LAPC-4 cells in the absence of androgens. In addition, IGFBP-2 significantly stimulated hTERT expression and telomerase activity in DU 145 cells. Thus, we demonstrated an inhibitory effect of IGFBP-2 on non-malignant prostate cells, but showed it to be stimulatory for prostate cancer cells in a MAP-kinase and androgen-modulated process. In conclusion, IGFBP-2 may play a role in the progression, but not in the initiation of the prostate cancer disease process, suggesting the existence of a molecular switch transitioning IGFBP-2 from a growth inhibitor to a pro-carcinogenic molecule.

Androstadienes↗
PubMed2003

Leptomycin B stabilizes and activates p53 in primary prostatic epithelial cells and induces apoptosis in the LNCaP cell line.

BACKGROUND: Previous studies showed that primary cultures of normal and malignant human prostatic epithelial cells are defective in their ability to upregulate the tumor suppressor protein p53 in response to DNA damage. This dysfunctional regulation of p53 may be relevant to both the high incidence of prostate cancer and its resistance to chemotherapy. Leptomycin B (LMB) has recently been found to increase the protein level and transcriptional activity of p53 by interfering with nucleocytoplasmic export and subsequent degradation by the proteasome. We investigated the ability of LMB to activate p53 in prostatic epithelial cells. METHODS: Primary cultures and the cell lines LNCaP and DU 145 were treated with LMB. p53 protein was evaluated in Western blots and by immunocytochemistry. Induction of downstream targets of p53 was evaluated in Western and Northern blots. Growth inhibition, cell cycle arrest, and apoptosis in response to LMB were measured in clonal growth assays, by flow cytometry, and by Hoescht/propidium iodide staining, respectively. RESULTS: Treatment of prostatic epithelial cells with LMB led to post-translational stabilization of p53, activation of downstream target genes, and induction of cell cycle arrest in primary cultures and apoptosis in LNCaP (with wild-type p53) but not DU 145 (with mutant p53) cells. CONCLUSIONS: p53 in primary cultures of normal and malignant prostate cells, although dysfunctional in that it is not responsive to DNA damage, is activated by LMB. The ability of LMB to stabilize p53 and induce expression of p53-responsive growth inhibitory genes may be a useful lead in the development of chemopreventive or therapeutic small molecules that can modulate p53 function in prostatic epithelial cells.

Antibiotics, Antineoplastic↗
PubMed2003

Inhibition of prostate cancer growth by vitamin D: Regulation of target gene expression.

Prostate cancer (PCa) cells express vitamin D receptors (VDR) and 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) inhibits the growth of epithelial cells derived from normal, benign prostate hyperplasia, and PCa as well as established PCa cell lines. The growth inhibitory effects of 1,25(OH)(2)D(3) in cell cultures are modulated tissue by the presence and activities of the enzymes 25-hydroxyvitamin D(3) 24-hydroxylase which initiates the inactivation of 1,25(OH)(2)D(3) and 25-hydroxyvitamin D(3) 1alpha-hydroxylase which catalyses its synthesis. In LNCaP human PCa cells 1,25(OH)(2)D(3) exerts antiproliferative activity predominantly by cell cycle arrest through the induction of IGF binding protein-3 (IGFBP-3) expression which in turn increases the levels of the cell cycle inhibitor p21 leading to growth arrest. cDNA microarray analyses of primary prostatic epithelial and PCa cells reveal that 1,25(OH)(2)D(3) regulates many target genes expanding the possible mechanisms of its anticancer activity and raising new potential therapeutic targets. Some of these target genes are involved in growth regulation, protection from oxidative stress, and cell-cell and cell-matrix interactions. A small clinical trial has shown that 1,25(OH)(2)D(3) can slow the rate of prostate specific antigen (PSA) rise in PCa patients demonstrating proof of concept that 1,25(OH)(2)D(3) exhibits therapeutic activity in men with PCa. Further investigation of the role of calcitriol and its analogs for the therapy or chemoprevention of PCa is currently being pursued.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2003

Primary culture model of peroxisome proliferator-activated receptor gamma activity in prostate cancer cells.

BRL 49653 (rosiglitazone) is a thiazolidinedione anti-diabetic drug that activates the nuclear receptor, peroxisome proliferator-activated receptor gamma (PPARgamma). Pilot clinical trials have shown evidence of therapeutic activity of PPARgamma agonists against prostate cancer. To more effectively use PPARgamma ligands to treat this common and generally chemo-resistant type of cancer, it will be necessary to better understand the nature of PPARgamma activity in prostate cancer cells. Tumor suppressor effects of activation of PPARgamma may include suppression of growth and/or induction of differentiation or apoptosis. We investigated responses of primary cultures of human prostatic cancer cells to BRL 49653. PPARgamma was expressed in all of the cell strains examined. BRL 49653 caused dose- and time-dependent growth inhibition that was associated with increased expression of the transcription repressor, transforming growth factor beta-stimulated clone 22 (TSC-22), and markedly increased expression of the secretory differentiation-associated gene adipophilin. Adipocyte-type fatty acid binding protein (aFABP), neutrophil gelatinase-associated lipocalin (NGAL), glycerol kinase (GyK), and beta-catenin, which are regulated by PPARgamma ligands in certain other types of cells, were not regulated by BRL 49653 in prostate cells. Upregulation of adipophilin coincided with morphological changes and the appearance of cytoplasmic vacuoles with ultrastructural features of secondary lysosomes. These results extend previous studies with established cancer cell lines and show that PPARgamma agonists can inhibit proliferation and modulate expression of secretory-associated genes in primary cultures of prostate cancer cells, further warranting consideration of these agents as pro-differentiating chemotherapeutic or chemoprevention agents for the treatment of prostate cancer.

Adenocarcinoma↗
PubMed2003

The role of vitamin D in prostate cancer.

Prostate cancer (PCa) cells harbor receptors for vitamin D (VDR) as well as androgens (AR). 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] increases AR expression and enhances androgen actions linking the two receptor systems. 1,25(OH)2D3 exhibits antiproliferative activity in both AR-positive and AR-negative PCa cells. Less calcemic analogs of 1,25(OH)2D3, with more antiproliferative activity, are being developed and will be more useful clinically. The mechanisms underlying differential analog activity are being investigated. In target cells, 1,25(OH)2D3 induces 24-hydroxylase, the enzyme that catalyzes its self-inactivation. Co-treatment with 24-hydroxylase inhibitors enhances the antiproliferative activity of calcitriol. Primary cultures of normal or cancer-derived prostatic epithelial cells express 1alpha-hydroxylase, the enzyme that catalyzes the synthesis of 1,25(OH)2D3, the levels being much lower in the cancer-derived cells and in PCa cell lines. This finding raises the possibility of using 25-hydroxyvitamin D3 [25(OH)D3] as a chemopreventive agent in PCa. In LNCaP human PCa cells, 1,25(OH)2D3 and its analogs exert antiproliferative activity predominantly by cell cycle arrest, but also induce apoptosis, although to a much lesser degree. Growth arrest is mediated by induction of IGF binding protein-3 (IGFBP-3), which in turn increases the expression of the cell cycle inhibitor p21, leading to growth arrest. Other actions of 1,25(OH)2D3 in PCa cells include promotion of pro-differentiation effects and inhibition of tumor cell invasion, metastasis and angiogenesis. Combination therapy with retinoids, other anticancer agents or 24-hydroxylase inhibitors augments the inhibitory activity of 1,25(OH)2D3 in PCa and provides another effective approach in PCa treatment. Small clinical trials have shown that 1,25(OH)2D3 can slow the rate of prostate specific antigen (PSA) rise in PCa patients, demonstrating proof of concept that 1,25(OH)2D3 or its analogs will be clinically effective in PCa therapy. Current research involves further investigation of the role of 1,25(OH)2D3 and its analogs for the therapy or chemoprevention of PCa.

Animals↗
PubMed2003

Oxidative 3alpha-hydroxysteroid dehydrogenase activity of human type 10 17beta-hydroxysteroid dehydrogenase.

In vitro enzyme assays have demonstrated that human type 10 17beta-hydroxysteroid dehydrogenase (17beta-HSD10) catalyzes the oxidation of 5alpha-androstane-3alpha,17beta-diol (adiol), an almost inactive androgen, to dihydrotestosterone (DHT) rather than androsterone or androstanedione. To further investigate the role of this steroid-metabolizing enzyme in intact cells, we produced stable transfectants expressing 17beta-HSD10 or its catalytically inactive Y168F mutant in human embryonic kidney (HEK) 293 cells. It was found that DHT levels in HEK 293 cells expressing 17beta-HSD10, but not its catalytically inactive mutant, will dramatically increase if adiol is added to culture media. Moreover, certain malignant prostatic epithelial cells have more 17beta-HSD10 than normal controls, and can generate DHT, the most potent androgen, from adiol. This event might promote prostate cancer growth. Analysis of the 17beta-HSD10 sequence shows that this enzyme does not have any ER retention signal or transmembrane segments and has not originated by divergence from a retinol dehydrogenase. The data suggest that the unique mitochondrial location of this HSD [Eur. J. Biochem. 268 (2001) 4899] does not prevent it from oxidizing the 3alpha-hydroxyl group of a C19 sterol in living cells. The experimental results lead to the conclusion that mitochondrial 17beta-HSD10 plays a significant part in a non-classical androgen synthesis pathway along with microsomal retinol dehydrogenases.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

Pathways mediating the growth-inhibitory actions of vitamin D in prostate cancer.

Vitamin D is emerging as an important dietary factor that affects the incidence and progression of many malignancies including prostate cancer. The active form of vitamin D, 1,25-dihydroxycholecalciferol [1,25(OH)(2)D(3)], inhibits the growth and stimulates the differentiation of prostate cancer cells. We have studied primary cultures of normal and cancer-derived prostatic epithelial cells as well as established human prostate cancer cell lines to elucidate the molecular pathways of 1,25(OH)(2)D(3) actions. These pathways are varied and appear to be cell specific. In LNCaP cells, 1,25(OH)(2)D(3) mainly causes growth arrest through the induction of insulin-like growth factor binding protein-3 and also stimulates apoptosis to a much smaller extent. We have used cDNA-microarray analyses to identify additional genes that are regulated by 1,25(OH)(2)D(3) and to raise novel therapeutic targets for use in the chemoprevention or treatment of prostate cancer. Less calcemic analogs of 1,25(OH)(2)D(3) that have more antiproliferative activity are being developed that will be more useful clinically. In target cells, 1,25(OH)(2)D(3) induces 24-hydroxylase, the enzyme that catalyzes its self inactivation. Cotreatment with 24-hydroxylase inhibitors enhances the antiproliferative activity of 1,25(OH)(2)D(3). The combination of other anticancer agents such as retinoids with vitamin D offers another promising therapeutic approach. A small clinical trial has shown that 1,25(OH)(2)D(3) can slow the rate of prostate-specific antigen increase in prostate cancer patients, which demonstrates proof of the concept that vitamin D or its analogs are clinically effective. Our research is directed at understanding the mechanisms of vitamin D action in prostate cells with the goal of developing chemoprevention and treatment strategies to improve prostate cancer therapy.

Calcitriol↗
PubMed2003

Human type 3 3alpha-hydroxysteroid dehydrogenase (aldo-keto reductase 1C2) and androgen metabolism in prostate cells.

Human aldo-keto reductases (AKRs) of the AKR1C subfamily function in vitro as 3-keto-, 17-keto-, and 20-ketosteroid reductases or as 3alpha-, 17beta-, and 20alpha-hydroxysteroid oxidases. These AKRs can convert potent sex hormones (androgens, estrogens, and progestins) into their cognate inactive metabolites or vice versa. By controlling local ligand concentration AKRs may regulate steroid hormone action at the prereceptor level. AKR1C2 is expressed in prostate, and in vitro it will catalyze the nicotinamide adenine dinucleotide (NAD(+))-dependent oxidation of 3alpha-androstanediol (3alpha-diol) to 5alpha-dihydrotestosterone (5alpha-DHT). This reaction is potently inhibited by reduced NAD phosphate (NADPH), indicating that the NAD(+): NADPH ratio in cells will determine whether AKR1C2 makes 5alpha-DHT. In transient COS-1-AKR1C2 and in stable PC-3-AKR1C2 transfectants, 5alpha-DHT was reduced by AKR1C2. However, the transfected AKR1C2 oxidase activity was insufficient to surmount the endogenous 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity, which eliminated 3alpha-diol as androsterone. PC-3 cells expressed retinol dehydrogenase/3alpha-HSD and 11-cis-retinol dehydrogenase, but these endogenous enzymes did not oxidize 3alpha-diol to 5alpha-DHT. In stable LNCaP-AKR1C2 transfectants, AKR1C2 did not alter androgen metabolism due to a high rate of glucuronidation. In primary cultures of epithelial cells, high levels of AKR1C2 transcripts were detected in prostate cancer, but not in cells from normal prostate. Thus, in prostate cells AKR1C2 acts as a 3-ketosteroid reductase to eliminate 5alpha-DHT and prevents activation of the androgen receptor. AKR1C2 does not act as an oxidase due to either potent product inhibition by NADPH or because it cannot surmount the oxidative 17beta-HSD present. Neither AKR1C2, retinol dehydrogenase/3alpha-HSD nor 11-cis-retinol dehydrogenase is a source of 5alpha-DHT in PC-3 cells.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

Vitamin D receptor start codon polymorphism (FokI) and prostate cancer progression.

Vitamin D plays an important role in cell growth and differentiation and is proposed to protect against cancer initiation and/or progression. The vitamin D receptor (VDR) has a thymine/cytosine (T/C) polymorphism located in the first of two potential start (ATG) codons that can be detected by a RFLP using the endonuclease FokI. The C variant, which lacks the first ATG, results in a shorter VDR and is referred to as the F allele. The T variant (f allele) initiates at the first ATG. We examined the association of the VDR FokI genotype with histopathological characteristics and prognosis of prostate cancer among 191 mostly Caucasian subjects who had undergone radical prostatectomy between 1984 and 1992. The frequencies of the FF, Ff, and ff genotypes were 41%, 38%, and 21%, respectively. Subjects with the ff genotype had a lower mean percentage of Gleason grade 4/5 cancer (30.3%) than subjects with the FF or Ff genotypes (42.8% and 43.8%, respectively; P = 0.015 by t test for ff versus FF + Ff). The data suggest that the presence of an F allele increased the risk of being diagnosed with more aggressive cancer because higher percentage of Gleason grade 4/5 is associated with worse prognosis. The age-adjusted risk of prostate-specific antigen failure was lower for the ff genotype than for the FF genotype by Cox proportional hazards analysis but did not achieve statistical significance (hazard ratio = 0.76; 95% confidence interval, 0.44-1.32). This risk reduction disappeared after further adjustment for percentage of Gleason grade 4/5, cancer volume, and preoperative serum prostate-specific antigen level (hazard ratio = 1.03; 95% confidence interval, 0.58-1.85). In conclusion, the ff genotype was associated with less aggressive histopathological findings than Ff or FF genotypes. Additional studies with a larger sample size and investigation of the functional significance of the FokI polymorphism in prostate cancer cells are warranted.

Base Sequence↗
PubMed2002

Polymorphisms in the androgen receptor and type II 5 alpha-reductase genes and prostate cancer prognosis.

BACKGROUND: Cytosine-adenine-guanine repeat length of the androgen receptor gene and the A49T and V89L polymorphisms of the 5 alpha-reductase (SRD5A2) gene have been associated with prostate cancer. METHODS: We investigated the relationship of the three genetic polymorphisms to tumor grade among 211 men who had undergone radical prostatectomy. Subjects had prostate cancer <3 cm(3) with a percentage of cancer represented by Gleason grade 4 or 5 (% Gleason grade 4/5) of either > or = 20% or < or = 5%. We also examined the association between those genetic markers and prostate specific antigen (PSA) failure among 112 subjects with > or = 20% Gleason grade 4/5. RESULTS: In cross-sectional analysis, none of the polymorphisms was a significant predictor of % Gleason grade 4/5. In longitudinal analysis, the LL genotype at the V89L site was associated with statistically significant four- to sixfold increase in PSA failure risk after adjustment for clinicopathologic variables. CONCLUSIONS: We observed poorer prognosis among men with the LL genotype at codon 89 of the SRD5A2 gene. Lack of consistency between studies must be resolved before clinical utility of this marker is established.

Biomarkers, Tumor↗
PubMed2002

Silencing of pi-class glutathione S-transferase in MDA PCa 2a and MDA PCa 2b cells.

BACKGROUND: Loss of expression of the glutathione S-transferase-pi (GSTP1) is the most common genetic alteration described in human prostate cancer, occurring in virtually all tumors regardless of grade or stage. Of the available human prostate cancer cell lines, only LNCaP mirrors this phenotype. We investigated whether the prostate cancer cell lines MDA PCa 2a and MDA PCa 2b share this phenotype. METHODS: GSTP1 protein and mRNA levels were assessed in the MDA PCa 2a and MDA PCa 2b cell lines by Western and Northern blot. DNA methylation was evaluated by Southern blot analysis of genomic DNA digested with the methylation-sensitive restriction enzymes BssHII, NotI, and SacII. Re-expression of GSTP1 was determined by RT-PCR following treatment with 5-azacytidine, a DNA methyltransferase inhibitor, and/or the histone deacetylase inhibitor trichostatin A (TSA). RESULTS: Like all human prostatic carcinomas in vivo, both the MDA PCa 2a and 2b cell lines lack protein and mRNA expression of GSTP1. This lack of expression is associated with methylation in the GSTP1 gene promoter. Treatment with the methyltransferase inhibitor 5-azacytidine resulted in re-expression of GSTP1. By itself, TSA did not result in re-expression of GSTP1, nor did it augment expression induced by 5-azacytidine. CONCLUSIONS: MDA PCa 2a and 2b appear to be useful models of human prostatic carcinoma in that they lack expression of GSTP1 due to gene silencing via promoter methylation. Inhibition of histone acetylation does not appear to affect GSTP1 expression.

DNA Methylation↗