Hormonal therapy for prostate cancer: Current topics and future perspectives

Nomogram for predicting the overall survival and cancer-specific survival of patients with intraductal carcinoma of the prostate

PURPOSE

Intraductal carcinoma of the prostate (IDC-P) is a histological subtype that differs from conventional acinar adenocarcinoma in terms of its origin, appearance, and pathological features. For IDC-P, there is currently no recognized best course of action, and its prognosis is unclear. The goal of this study is to analyze independent prognostic factors in IDC-P patients and to develop and validate a nomogram to predict overall survival (OS) and cancer-specific survival (CSS).

METHODS

Clinical data for IDC-P patients were collected from the Surveillance, Epidemiology, and End Results database. To identify the independent variables influencing prognosis, multivariate Cox regression analysis was performed. A nomogram model was created utilizing these variables after comparing the variations in OS and CSS among various subgroups using Kaplan‒Meier curves. Internal validation of the nomograms was verified using the bootstrap resampling method.

RESULTS

The study included 280 IDC-P patients in total. Marital status, summary stage, grade, and the presence of lung metastases were significant factors impacting OS, and CSS was significantly influenced by marital status, summary stage, AJCC stage, the presence of lung metastases, the presence of bone metastases, and PSA according to univariate and multivariate Cox regression models (P < 0.05). Nomogram models were created to estimate OS and CSS using these parameters. The OS prediction model's C-index was 0.744, whereas the CSS prediction model's C-index was 0.831.

CONCLUSION

We developed and verified nomogram models for the prediction of 1-, 3-, and 5-year OS and CSS in patients with IDC-P. These nomograms serve as a resource for evaluating patient prognosis, therapy, and diagnosis, ultimately improving clinical decision-making accuracy.

Baicalein suppresses the androgen receptor (AR)-mediated prostate cancer progression via inhibiting the AR N-C dimerization and AR-coactivators interaction

BACKGROUND

Androgen receptor (AR) plays a critical role in prostate cancer (PCa) development and progression. Androgen deprivation therapy with antiandrogens to reduce androgen biosynthesis or prevent androgens from binding to AR are widely used to suppress AR-mediated PCa growth. However, most of ADT may eventually fail with development of the castration resistance after 12-24 months. Here we found that a natural product baicalein can effectively suppress the PCa progression via targeting the androgen-induced AR transactivation with little effect to AR protein expression.

METHODS

PCa cells including LNCaP, CWR22Rv1, C4-2, PC-3, and DU145, were treated with baicalein and luciferase assay was used to evaluate their effect on the AR transactivation. Cell growth and IC50 were determined by MTT assay after 48 hrs treatment. RT-PCR was used to evaluate the mRNA levels of AR target genes including PSA, TMPRSS2, and TMEPA1. Western blot was used to determine AR and PSA protein expression.

RESULTS

The natural product of baicalein can selectively inhibit AR transactivation with little effect on the other nuclear receptors, including ERα, and GR. At a low concentration, 2.5 μM of baicalein effectively suppresses the growth of AR-positive PCa cells, and has little effect on AR-negative PCa cells. Mechanism dissection suggest that baicalein can suppress AR target genes (PSA, TMPRSS2, and TMEPA1) expression in both androgen responsive LNCaP cells and castration resistant CWR22Rv1 cells, that may involve the inhibiting the AR N/C dimerization and AR-coactivators interaction.

CONCLUSIONS

Baicalein may be developed as an effective anti-AR therapy via its ability to inhibit AR transactivation and AR-mediated PCa cell growth.

GnRH agonists and the rapidly increasing use of combined androgen blockade in prostate cancer

The discovery of medical castration with GnRH agonists in 1979 rapidly replaced surgical castration and high doses of estrogens for the treatment of prostate cancer. Soon afterwards, it was discovered that androgens were made locally in the prostate from the inactive precursor DHEA of adrenal origin, a mechanism called intracrinology. Taking into account these novel facts, combined androgen blockade (CAB) using a pure antiandrogen combined with castration in order to block the two sources of androgens was first published in 1982. CAB was the first treatment shown in randomized and placebo-controlled trials to prolong life in prostate cancer, even at the metastatic stage. Most importantly, the results recently obtained with the novel pure antiandrogen enzalutamide as well as with abiraterone, an inhibitor of 17α-hydroxylase in castration-resistant prostate cancer, has revitalized the CAB concept. The effects of CAB observed on survival of heavily pretreated patients further demonstrates the importance of the androgens made locally in the prostate and are a strong motivation to apply CAB to efficiently block all sources of androgens earlier at start of treatment and, even better, before metastasis occurs. The future of research in this field thus seems to be centered on the development of more potent blockers of androgens formation and action in order to obtain better results at the metastatic stage and, for the localized stage, reduce the duration of treatment required to achieve complete apoptosis and control of prostate cancer proliferation before it reaches the metastatic or noncurable stage.

The selective inhibitory effect of a synthetic tanshinone derivative on prostate cancer cells

BACKGROUND

Androgen receptor (AR) is the main therapeutic target for the treatment of prostate cancer (PCa). Anti-androgens to reduce or prevent androgens binding to AR are widely used to suppress AR-mediated PCa growth; however, the androgen depletion therapy (ADT) is only effective for a short period of time. Here we tested PTS33, a new sodium derivative of cryptotanshinone, which can effectively inhibit the DHT-induced AR transactivation and PCa cell growth, and then explored the effects of PTS33 on inhibiting the expressions of AR target genes and proteins.

METHODS

PCa cells, LNCaP, CWR22Rv1, C4-2, PC-3, and DU145, were treated with PTS33 and luciferase assay was used to evaluate the ability of each to regulate AR transactivation. RT-PCR was used to evaluate the mRNA levels of AR target genes such as PSA, TMPRSS2, and TMEPA1. Western blot was used to determine AR, PSA, estrogen receptor alpha (ERα), glucocorticoid receptor (GR), and progesterone receptor (PR) protein expression. Cell growth and IC50 were determined by MTT assay after 48 hr treatment.

RESULTS

Our data showed that PTS33 selectively inhibits AR activities, but PTS33 does not repress the activities of other nuclear receptors, including ERα, GR, and PR. At a low concentration, 2 µM of PTS33 effectively suppresses the growth of AR-positive PCa cells, and has little effect on AR-negative PCa cells. Furthermore, our data indicated that PTS33 could modulate AR transactivation and suppress the AR target genes (PSA, TMPRSS2, and TMEPA1) expression in both androgen responsive PCa LNCaP cells and castration-resistant C4-2 cells. In addition, PTS33 can also inhibit estrogen/Δ5-androstenediol induced AR activities. The mechanistic studies indicate that PTS33 can inhibit AR function by suppression of AR protein expression, the AR N-C interaction, and AR-coregulator interaction.

CONCLUSIONS

PTS33 has shown a good efficacy to inhibit AR transactivation, block AR regulated gene expression, and reduce cell growth in AR positive PCa cells. The structure of PTS33 could be used as a base for development of novel AR signaling inhibitors to treat PCa.

Prostate cancer in elderly Croatian men: 5-HT genetic polymorphisms and the influence of androgen deprivation therapy on osteopenia--a pilot study

BACKGROUND

The aim of this study was to determine the relationship between body mass index, biochemical parameters, and 5-hydroxytryptamine (5-HT) genetic polymorphisms and prostate dysfunction in an elderly general male population.

RESULTS

One hundred and seventeen elderly male subjects [60 men without symptoms of prostate hyperplasia, 42 men with untreated benign prostatic hyperplasia (BPH), and 15 men with prostate cancer (PCa)] treated with finasteride or flutamide were included. Multiple comparisons showed significant difference in age, T-score, concentration of phosphorus, calcium, C-reactive protein, and prostate-specific antigen (PSA) between the groups. T-score was the lowest and phosphorus concentration was the highest in the PCa group. Highest PSA, proteins, calcium, and Hekal's formula score were found in the BPH group. Patients with PCa were more frequent GG+GA carriers of 5-HT1B 1997A/G gene polymorphism (p=0.035). Univariate regression analysis showed association of PCa-treated subjects with age (p=0.010) and 5-HT1B genetic polymorphism (p=0.018). Antiandrogen therapy affects T-score (p=0.017), serum phosphorus (p=0.008), glucose (p=0.036), and total proteins (p=0.050). Multivariate-stepwise logistic regression analysis showed the significant association of treated PCa with age (p=0.028) and inorganic phosphorus (p=0.005), and a marginal association with ultrasonographic T-score (p=0.052).

CONCLUSIONS

Antiandrogen therapy might induce bone mineral loss in elderly PCa patients. Preliminary data imply that the genetic variants of the 5-HT1B receptor might be associated with PCa.