Fumio Ishizaki

Androgen deprivation promotes intratumoral synthesis of dihydrotestosterone from androgen metabolites in prostate cancer

Intratumoral synthesis of dihydrotestosterone (DHT) from precursors cannot completely explain the castration resistance of prostate cancer. We showed that DHT was intratumorally synthesized from the inactive androgen metabolites 5α-androstane-3α/β,17β-diol (3α/β-diol) in prostate cancer cells via different pathways in a concentration-dependent manner. Additionally, long-term culture in androgen-deprived media increased transcriptomic expression of 17β-hydroxysteroid dehydrogenase type 6 (HSD17B6), a key enzyme of oxidative 3α-HSD that catalyzes the conversion of 3α-diol to DHT in prostate cancer cells. Correspondingly, the score for HSD17B6 in tissues of 42 prostate cancer patients undergoing androgen deprivation therapy (ADT) was about 2-fold higher than that in tissues of 100 untreated individuals. In men receiving ADT, patients showing biochemical progression had a higher HSD17B6 score than those without progression. These results suggested that 3α/β-diol also represent potential precursors of DHT, and the back conversion of DHT from androgen derivatives can be a promising target for combination hormone therapy.

Prediction of pathological and oncological outcomes based on extended prostate biopsy results in patients with prostate cancer receiving radical prostatectomy: a single institution study

BackgroundThe prediction of pathological outcomes prior to surgery remains a challenging problem for the appropriate surgical indication of prostate cancer. This study was performed to identify preoperative values predictive of pathological and oncological outcomes based on standardized extended prostate biopsies with core histological results diagrammed/mapped in patients receiving radical prostatectomy for prostate cancer clinically diagnosed as localized or locally advanced disease.MethodsIn 124 patients with clinically localized or locally advanced prostate cancer (cT1c–cT3a) without prior treatment, pathological outcomes on the surgical specimen including seminal vesicle involvement (SVI), positive surgical margin (PSM), and perineural invasion (PNI) were studied in comparison with clinical parameters based on the results of 14-core prostate biopsies comprising sextant, laterally-directed sextant, and bilateral transition zone (TZ) sampling.ResultsConcerning the association of pathological outcomes with oncological outcomes, patients with PSM and PNI on surgical specimens had poorer biochemical-progression-free survival than those without PSM (logrank p = 0.002) and PNI (p = 0.003); it was also poorer concerning SVI, although the difference was not significant (p = 0.120). Concerning the impact of clinical parameters on these pathological outcomes, positive TZ and multiple positive biopsy cores in the prostatic middle were independent values predictive of SVI with multivariate analyses (p = 0.020 and p = 0.025, respectively); both positive TZ and multiple positive prostatic middle biopsies were associated with larger tumor volume (p < 0.001 in both). The percentage of positive biopsy cores (%positive cores) and biopsy Gleason score were independent values predictive of PSM (p = 0.001) and PNI (p = 0.001), respectively. Multiple positive cores in the prostatic base were associated with proximal/bladder-side PSM (p < 0.001), and also linked to poorer biochemical-progression-free survival (p = 0.004). Clinical T stage had no association with these pathological outcomes.Conclusions%positive cores and Gleason score in extended biopsies were independent values predictive of PSM and PNI in prostate cancer clinically diagnosed as localized or locally advanced disease, respectively, which were associated with poorer oncological outcomes. When diagramming biopsy-core results, extended biopsy may provide additional information for predicting oncological and pathological outcomes including SVI in patients clinically diagnosed as having localized or locally advanced disease.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8790262771042628

Insulin-like growth factor-1 is associated with regulation of the luteinizing hormone production in men receiving androgen deprivation therapy with gonadotropin-releasing hormone analogues for localized prostate cancer.

BACKGROUND Luteinizing hormone (LH) during androgen-deprivation therapy (ADT) with gonadotropin-releasing hormone analogues (GnRHa) has been thought to be biologically inactive, and the regulation of LH during ADT with GnRHa is thus unknown. Insulin-like growth factor-1 (IGF-1) is involved in the regulation of cell proliferation and differentiation, and IGF-1 production in the liver is dependent on growth hormone (GH) secretion from the anterior pituitary. Despite the presence of IGF-1 receptors in the gonadotroph, associations between the GH/IGF-1 and pituitary-gonadal axes, e.g., whether IGF-1 elicits the LH secretion, remain unclear. METHODS Seventy-one patients with localized prostate cancer, who received ADT with GnRHa, were prospectively studied based on their blood samples before treatment and after ADT for 6 months. We employed highly sensitive assays for measurement of serum testosterone (electrochemiluminescence immunoassay), GH/IGF-1 (radioimmunoassay), adrenocorticotropic hormone (ACTH: immunoradiometric assay), LH (chemiluminescent immunoassay), and dehydroepiandrosterone sulfate (DHEA-S: chemiluminescent enzyme immunoassay). RESULTS No correlation was noted between the pretreatment LH and IGF-1 levels; after ADT, the serum LH level was closely correlated with the IGF-1 concentration [Spearmans correlation coefficient (rs) = 0.370, P = 0.001]. The serum levels of androgens and gonadotropins reduced following ADT (P < 0.001 in all). The serum IGF-1 level increased (22 ± 6 nmol/L) compared with that at the baseline (19 ± 5 nmol/L) (P < 0.001), but no change was observed in the serum GH concentration between before and after ADT (1.4 ± 2.3 vs. 0.9 ± 0.9 μg/L, respectively, P = 0.691). The serum testosterone level was not correlated with the LH level either before or after ADT. The testosterone and DHEA-S levels after ADT were correlated with ACTH concentration (rs = 0.367, P = 0.002 and rs = 0.354, P = 0.002, respectively). We did not identify any correlations between the serum IGF-1 concentration and Gleason score, PSA value, or androgen levels. CONCLUSIONS During ADT with GnRHa, IGF-1 possibly promotes LH production, although its role is unclear. Associations among pituitary-gonadal, pituitary-adrenal, and GH/IGF-1 axes represented by IGF-1-mediated LH secretion and ACTH-mediated androgen synthesis are of interest, since both prostate epithelium proliferation and male anabolic activity are involved in these 3 axes. Assessment of oncologic outcomes is warranted for their significance in patients with prostate cancer.

Trilostane, an inhibitor of 3β-hydroxysteroid dehydrogenase, has an agonistic activity on androgen receptor in human prostate cancer cells

The intracellular androgen metabolism and cell activity in prostate cancer cells with mutated (LNCaP-FGC) or wild-type (VCaP) androgen receptors in the presence of trilostane, an inhibitor of 3β-hydroxysteroid dehydrogenase, were examined. Trilostane suppressed the intracellular production of androstenedione, testosterone, and dihydrotestosterone from dehydroepiandrosterone in LNCaP-FGC cells. In both LNCaP-FGC and VCaP cell types, the prostate-specific antigen (PSA) levels in media were increased by trilostane alone in a concentration-dependent manner. Both cells pretreated with trilostane showed a dose-dependent decrease in PSA production with bicalutamide (P<0.001). Trilostane should be used with particular concern when treating prostate cancer.

Altered association of interleukin-6 with sex steroids in lipid metabolism disorder in men with prostate cancer receiving androgen deprivation therapy.

Interleukin‐6 produced in adipose tissue plays a role in lipid metabolism, and also interacts with sex steroids. This study was performed to elucidate the mechanism of lipid metabolism disorder during androgen deprivation therapy (ADT) in terms of the association of interleukin‐6 with sex steroids.

Decrease in lean body mass in men with prostate cancer receiving androgen deprivation therapy: mechanism and biomarkers.

OBJECTIVE To elucidate the mechanism of the androgen deprivation therapy (ADT)-related decrease in lean body mass (LBM). MATERIALS AND METHODS The LBM and blood samples were studied before and after 6 months of ADT in 72 patients with localized prostate cancer. The LBM was assessed using a foot-to-foot bioelectrical impedance analyzer. RESULTS Before ADT, the LBM correlated with none of the serum sex steroid levels; however, it correlated closely with serum 5α-androstane-3α,17β-diol glucuronide (Spearmans rank correlation coefficient = 0.409, P = .001) and insulin-like growth factor-1 (IGF-I, Spearmans rank correlation coefficient = 0.329, P = .005). After ADT, the LBM decreased by 0.9% (P = .036), and the serum testosterone and dihydrotestosterone had decreased by 96.8% and 94.3%, respectively (P <.001 for both), and the IGF-I had increased by 11.6% (from 19.9 to 22.2 nmol/L, P = .001). The serum 1,25-dihydroxyvitamin D3 [1,25(OH)2D] levels decreased after ADT by 9.8% (from 66.2 to 59.7 pg/mL, P = .008), and the post-treatment LBM correlated inversely with 1,25(OH)2D (Spearmans rank correlation coefficient = -0.343, P = .003). The post-treatment LBM was dissociated with 5α-androstane-3α,17β-diol glucuronide and IGF-I. The pretreatment and post-treatment LBMs both correlated inversely with serum sex hormone-binding globulin (P = .024 and P = .016, respectively). CONCLUSION The deficiency in androgen levels was suggested to be a link to the ADT-related decrease in LBM; the androgen metabolite 5α-androstane-3α,17β-diol glucuronide has a potential value for assessing the LBM in untreated men. IGF-I also promotes muscle building and is positively regulated during ADT. Sex hormone-binding globulin possibly accelerates the ADT-related decrease in LBM. Although the mechanism for the decrease in 1,25(OH)2D and its inverse correlation with LBM during ADT is unclear, 1,25(OH)2D might be a biomarker reflecting the ADT-related decrease in LBM.

Deficiency in androgens and upregulation of insulin-like growth factor-1 are involved in high bone turnover in men receiving androgen deprivation therapy for prostate cancer

OBJECTIVE This study was performed to elucidate the mechanism of high bone turnover during androgen deprivation therapy (ADT) in terms of osteogenic endocrine activity by testosterone, adrenal androgens, and insulin-like growth factor-1 (IGF-I), and to identify markers reflecting the bone mineral density (BMD) during ADT. DESIGN BMD and samples of blood and urine were studied before and after 6months of ADT in 70 patients with localized prostate cancer. RESULTS Before ADT, serum free-testosterone, dehydroepiandrosterone sulfate (DHEA-S), androstenedione, and IGF-I levels were correlated with BMD (rs=0.344, p=0.004; rs=0.264, p=0.027; rs=0.329, p=0.005; rs=0.300, p=0.012, respectively). The serum IGF-I level was independently correlated with the pretreatment BMD (Multivariate p=0.001). These relationships disappeared after ADT (p=0.519, 0.316, 0.116, and 0.597, respectively). After ADT, serum levels of free-testosterone decreased (7.9 to 0.2pg/mL), and DHEA-S and androstenedione were also reduced (3.6 to 2.3μmol/L and 5.6 to 2.9nmol/L, respectively) (p<0.001 in all). In contrast, IGF-I levels were elevated after ADT by 11.6% (19.9 to 22.3nmol/L, p<0.001). Delta-values of IGF-I (post- minus pretreatment levels, mean: +2.2, ranged between -7.1 and +15.3) were inversely correlated with the pretreatment (rs=-0.333 p=0.005) and post-treatment (rs=-0.408, p=0.001) BMD. After ADT, the serum IGF-I level was closely correlated with the serum level of the bone formation marker bone-specific alkaline phosphatase (BAP) (rs=0.328, p=0.006), and delta-IGF-I and delta-BAP showed a close positive correlation (rs=0.388, p=0.001). The post-treatment BMD was correlated only with the urine deoxypyridinoline (DPD) concentration (rs=-0.302, p=0.024) among the bone formation/resorption markers including serum/urine N-telopeptide. CONCLUSIONS Serum IGF-I levels increased during ADT in men with a low BMD. Coupled with reduced androgen levels, elevated IGF-I levels, which were positively correlated with BAP during ADT, possibly explain the mechanism of ADT-related high bone turnover. The increase of IGF-I is more prominent in men whose BMD is already low at the baseline, and urine DPD might be a marker that reflects BMD during ADT.

A case of normotensive incidentally discovered adrenal pheochromocytoma

Pheochromocytomas are catecholamine‐producing neuroendocrine tumors that arise from the adrenal medulla. The clinical presentation includes headache, palpitation, and hypertension, but pheochromocytomas are sometimes clinically silent. The present case highlights the importance of biochemical testing for pheochromocytoma in patients with adrenal incidentaloma, even if they are completely normotensive and asymptomatic.

Dihydrotestosterone synthesis pathways from inactive androgen 5α-androstane-3β,17β-diol in prostate cancer cells: Inhibition of intratumoural 3β-hydroxysteroid dehydrogenase activities by abiraterone

Intratumoural dihydrotestosterone (DHT) synthesis could be an explanation for castration resistance in prostate cancer (PC). By using liquid chromatography-mass spectrometry, we evaluated the intratumoral DHT synthesis from 5α-androstane-3β,17β-diol (3β-diol), which is inactive androgen metabolized from DHT. 3β-diol had biochemical potential to be converted to DHT via three metabolic pathways and could stimulate PC cell growth. Especially, 3β-diol was not only converted back to upstream androgens such as dehydroepiandrosterone (DHEA) or Δ5-androstenediol but also converted directly to DHT which is the main pathway from 3β-diol to DHT. Abiraterone had a significant influence on the metabolism of DHEA, epiandrosterone and 3β-diol, by the inhibition of the intratumoural 3β-hydroxysteroid dehydrogenase (3β-HSD) activities which is one of key catalysts in androgen metabolic pathway. The direct-conversion of 3β-diol to DHT was catalysed by 3β-HSD and abiraterone could inhibit this activity of 3β-HSD. These results suggest that PC had a mechanism of intratumoural androgen metabolism to return inactive androgen to active androgen and intratumoural DHT synthesis from 3β-diol is important as one of the mechanisms of castration resistance in PC. Additionally, the inhibition of intratumoural 3β-HSD activity could be a new approach to castration-resistant prostate cancer treatment.

Abstract 960: Intratumoral dihydrotestosterone regulation by conversion of androstanediol to dihydrotestosterone in prostate cancer

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Purpose It has become apparent that resurgent androgen receptor activity in castration-resistant prostate cancer can be accounted for in part through intratumoral androgen synthesis. The potent androgen dihydrotestosterone (DHT) yields an inactive androgen 5α-androstane-3α17α-diol (androstanediol/3α-diol) in the prostate. The metabolism of 3α-diol and relationships among other androgens have not been elucidated. Therefore, we studied the metabolism of 3α-diol in prostate cancer cells, as well as the expression of 17α-hydroxysteroid dehydrogenase 6 (17α-HSD6), a key enzyme of oxidative 3α-HSD that converts 3α-diol into DHT, in prostate cancer cells and tissues using real time-PCR and immunohistochemistry. Finally, we studied the correlation between serum 3α-diol G levels and androgens in localized prostate cancer patients. Methods LNCaP and VCaP cells were cultured in the hormone-depleted medium with presence/absence of 3α-diol, and the intracellular levels of androstenedione, testosterone and DHT were concurrently determined by liquid chromatography tandem mass spectrometry. LNCaP and VCaP cells were exposed to 3α-diol and bicalutamide in various concentrations. Prostate-specific antigen (PSA) levels in media were assayed. To examine the long term effect of androgen deprivation, LNCaP was cultured in hormone-depleted medium with 1nM DHEA. Transcriptome expression was analyzed to detect expression levels of 17α-HSD6. Expression scores for 17α-HSD6 in radical prostatectomy specimens treated with or without androgen deprivation therapy (ADT) were evaluated using immunohistochemistry. Seventy-two patients with localized prostate cancer patients were prospectively studied based on blood samples before and after ADT for 6 months. Results DHT was synthesized from 3α-diol in prostate cancer cells. Prostate cancer cells produced PSA in a dose-dependent manner with 3α-diol. Prostate cancer cells pretreated with 3α-diol showed a dose-dependent decrease in PSA production with bicalutamide. In the lower passages LNCaP cells treated with DHEA, expression of 17α-HSD6 showed much less striking change. However, in the higher passage LNCaP cells, 17α-HSD6 was up-regulated. The score for 17α-HSD6 in prostate cancer tissues treated with ADT was significantly higher than that without ADT (p<0.001). There were significant positive relationships between serum DHEA-S and 3α-diol G levels before and after ADT. Conclusion We verified the synthesis of DHT from 3α-diol in prostate cancer cells in this study and elucidated that the serum 3α-diol G level well reflects the adrenal androgen milieu in localized prostate cancer patients. Therefore, 3α-diol can be a potential precursor of the most active androgen DHT in prostate cancer. Our data suggest that the adrenal androgen-DHT axis can be a potential therapeutic target for treating prostate cancer. 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 960. doi:1538-7445.AM2012-960