Kazutaka Narimoto

Prostate cancer stromal cells and LNCaP cells coordinately activate the androgen receptor through synthesis of testosterone and dihydrotestosterone from dehydroepiandrosterone

One of the mechanisms through which advanced prostate cancer (PCa) usually relapses after androgen deprivation therapy (ADT) is the adaptation to residual androgens in PCa tissue. It has been observed that androgen biosynthesis in PCa tissue plays an important role in this adaptation. In the present study, we investigated how stromal cells affect adrenal androgen dehydroepiandrosterone (DHEA) metabolism in androgen-sensitive PCa LNCaP cells. DHEA alone had little effect on prostate-specific antigen (PSA) promoter activity and the proliferation of LNCaP cells. However, the addition of prostate stromal cells or PCa-derived stromal cells (PCaSC) increased DHEA-induced PSA promoter activity via androgen receptor activation in the LNCaP cells. Moreover, PCaSC stimulated the proliferation of LNCaP cells under physiological concentrations of DHEA. Biosynthesis of testosterone or dihydrotestosterone from DHEA in stromal cells and LNCaP cells was involved in this stimulation of LNCaP cell proliferation. Androgen biosynthesis from DHEA depended upon the activity of various steroidogenic enzymes present in stromal cells. Finally, the dual 5alpha-reductase inhibitor dutasteride appears to function not only as a 5alpha-reductase inhibitor but also as a 3beta-hydroxysteroid dehydrogenase inhibitor in LNCaP cells. Taken together, this coculture assay system provides new insights of coordinate androgen biosynthesis under the microenvironment of PCa cells before and after ADT, and offers a model system for the identification of important steroidogenic enzymes involved in PCa progression and for the development of the corresponding inhibitors of androgen biosynthesis.

Tranilast inhibits hormone refractory prostate cancer cell proliferation and suppresses transforming growth factor β1-associated osteoblastic changes

Tranilast is a therapeutic agent used in treatment of allergic diseases, although it has been reported to show anti‐tumor effects on some cancer cells. To elucidate the effects of tranilast on prostate cancer, we investigated the mechanisms of its anti‐tumor effect on prostate cancer.

Risedronate Recovers Bone Loss in Patients With Prostate Cancer Undergoing Androgen-deprivation Therapy

OBJECTIVES To perform a prospective observational study between risedronate and no risedronate (control) groups to determine the effectiveness of risedronate against bone loss in patients with prostate cancer (PCa) receiving androgen-deprivation therapy (ADT). ADT for PCa has iatrogenic complications (eg, bone loss and fracture). METHODS We enrolled 60 Japanese patients with PCa who were receiving ADT or were newly scheduled for ADT. The lumbar spine bone mineral density (BMD) was determined by dual-energy x-ray absorptiometry. Patients with a BMD <90% of the young adult mean received risedronate. We analyzed 29 and 27 patients in the risedronate and control groups, respectively. The BMD, urinary deoxypyridinoline, and serum bone alkaline phosphatase were measured as bone turnover markers at 6 and 12 months. RESULTS The BMD/young adult mean ratio correlated inversely with the duration of ADT. The initial mean BMD was significantly lower in the risedronate group than in the control group (1.02 +/- 0.19 vs 1.19 +/- 0.16 g/cm(2)). We focused on patients treated with ADT for >6 months. The mean percentage of changes in the BMD/young adult mean ratio of the risedronate and control groups was +2.6 +/- 4.5% and -2.8 +/- 2.6% after 1 year, respectively (P = .0001). The urinary deoxypyridinoline and bone alkaline phosphatase in the risedronate group decreased significantly after 12 months compared with the levels in the controls. CONCLUSIONS The results of our study have shown that oral administration of risedronate is effective for the recovery of ADT-induced bone loss in patients with PCa.

Adrenal androgen levels as predictors of outcome in castration‐resistant prostate cancer patients treated with combined androgen blockade using flutamide as a second‐line anti‐androgen

Objectives:  To analyze the clinical effects of flutamide as a second‐line anti‐androgen for combined androgen blockade in patients with castration‐resistant prostate cancer (CRPC) initially treated with bicalutamide as a first‐line anti‐androgen.

Tissue-specific differentially methylated regions of the human VASA gene are potentially associated with maturation arrest phenotype in the testis

Numerous CpG islands containing tissue-specific differentially methylated regions (TDMRs) are potential methylation sites in normal cells and tissues. The VASA (also known as DDX4) gene is believed to be under the control of TDMRs. A total of 131 male patients with idiopathic azoospermia or severe oligospermia were evaluated histologically, and the methylation status of CpG islands in the VASA gene was screened. Genome DNAs were obtained from testicular biopsy and modified with sodium bisulfite, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was applied. This system is capable of analyzing both the methylated and unmethylated CpG island in the genome. The methylation analysis is conducted by an epigram as graphic data. On histological assessment, 17 of 131 patients revealed maturation arrest (MA).In all, 6 of the 17 patients showed particularly high VASA TDMR methylation rates, whereas the remaining 11 patients and controls had low methylation rates. This study may imply that the VASA TDMR methylation is significantly higher among patients with MA, in whom the VASA gene expression was silenced. This finding represents an important contribution to the molecular basis of meiotic arrest as one possible cause of idiopathic infertility.

CTEN/tensin 4 expression induces sensitivity to paclitaxel in prostate cancer

Recently, we established paclitaxel‐resistant prostate cancer cell lines (PC‐3‐TxR and DU145‐TxR). To determine the mechanisms of paclitaxel resistance in PC‐3‐TxR cells, we compared the gene expression profiles between PC‐3 and PC‐3‐TxR cells. Our results indicated that expression of the C‐terminal tensin like protein (CTEN, tensin 4) gene was down‐regulated by 10‐fold in PC‐3‐TxR cells. We investigated the possibility that CTEN overexpression restores paclitaxel sensitivity.

The relationship of serum and salivary cortisol levels to male sexual dysfunction as measured by the International Index of Erectile Function.

To evaluate the biomarkers of sexual function, we investigated the relationship between questionnaire responses and biological hormones such as testosterone (T) and cortisol (F) in serum and saliva. The study population included 105 men aged 30–72 years (mean: 49±4.5, median: 49). Levels of all serum hormones (Total-T, Free-T, Bioavailable-T, Total-F and Bioavailable-F) and salivary hormones (Saliva-T and Saliva-F) were measured directly by liquid chromatography/tandem mass spectrometry. The International Index of Erectile Function (IIEF) was used as a questionnaire to evaluate sexual dysfunction. Free-T and Bioavailable-T showed significant inverse correlations with age (P<0.01). In the group not taking antidepressants, the levels of Bioavailable-F and Saliva-F showed significant inverse correlations with a portion of the IIEF score (P<0.05). However, reductions in Bioavailable-T and Saliva-T showed no association with the IIEF score. In the group taking antidepressants, these hormone levels showed no correlation with IIEF.

Postoperative voiding function in patients undergoing tension-free vaginal mesh procedure for pelvic organ prolapse

Introduction and hypothesisWe compared pre- and postoperative voiding function in patients with POP and assessed the efficacy of urodynamic studies in these cases.MethodsForty-six patients treated with the tension-free vaginal mesh (TVM) procedure between January 2009 and February 2010 underwent pressure flow study pre- and postoperatively. Pre- and postoperative voiding functions were assessed according to Schäfer nomograms.ResultsThe mean postoperative detrusor pressure at maximal flow was decreased significantly compared with that preoperatively. The mean maximum flow rate was also improved significantly and the proportion of normal contractility was increased significantly after the operation, as was the proportion of non-obstructive patients.ConclusionsThe TVM procedure for pelvic organ prolapse improved both detrusor contractility and urethral obstruction.

Tumor-associated macrophages promote prostate cancer migration through activation of the CCL22-CCR4 axis

Previous studies have found that tumor-associated macrophages (TAMs) promote cancer progression. We previously reported that TAMs promote prostate cancer metastasis via activation of the CCL2–CCR2 axis. The CCR4 (receptor of CCL17 and CCL22) expression level in breast cancer was reported to be associated with lung metastasis. The aim of this study was to elucidate the role of CCR2 and CCR4 in prostate cancer progression. CCR2 and CCR4 were expressed in human prostate cancer cell lines and prostate cancer tissues. In vitro co-culture of prostate cancer cells and macrophages resulted in increased CCL2 and CCR2 levels in prostate cancer cells. The addition of CCL2 induced CCL22 and CCR4 production in prostate cancer cells. The migration and invasion of prostate cancer cells via enhanced phosphorylation of Akt were promoted by CCL17 and CCL22. CCR4 may be a potential candidate for molecular-targeted therapy.

The relationship between prostate-specific antigen and TNM classification or Gleason score in prostate cancer patients with low prostate-specific antigen levels

Prostate‐specific antigen (PSA) is a useful biomarker for risk classification in patients with prostate cancer. However, it is unclear whether a correlation exists between low PSA levels (<10 ng/ml) at diagnosis and prognosis.