Metastatic prostate cancer in the modern era of PSA screening

ABSTRACT Introduction To characterize initial presentation and PSA screening status in a contemporary cohort of men treated for metastatic prostate cancer at our institution. Materials and methods We reviewed records of 160 men treated for metastatic prostate cancer between 2008-2014 and assessed initial presentation, categorizing patients into four groups. Groups 1 and 2 presented with localized disease and received treatment. These men suffered biochemical recurrence late (>1 year) or earlier (<1 year), respectively, and developed metastases. Groups 3 and 4 had asymptomatic and symptomatic metastases at the outset of their diagnosis. Patients with a first PSA at age 55 or younger were considered to have guideline-directed screening. Results Complete records were available on 157 men for initial presentation and 155 men for PSA screening. Groups 1, 2, 3 and 4 included 27 (17%), 7 (5%), 69 (44%) and 54 (34%) patients, respectively. Twenty (13%) patients received guideline-directed PSA screening, 5/155 (3%) patients presented with metastases prior to age 55 with their first PSA, and 130/155 (84%) had their first PSA after age 55, of which 122/130 (94%) had metastasis at the time of diagnosis. Conclusion Despite widespread screening, most men treated for metastatic prostate cancer at our institution presented with metastases rather than progressed after definitive treatment. Furthermore, 25 (16%) patients received guideline-directed PSA screening at or before age 55. These data highlight that, despite mass screening efforts, patients treated for incurable disease at our institution may not have been a result of a failed screening test, but a failure to be screened.

Metastatic prostate cancer in the modern era of PSA screening.

INTRODUCTION: To characterize initial presentation and PSA screening status in a contemporary cohort of men treated for metastatic prostate cancer at our institution. MATERIALS AND METHODS: We reviewed records of 160 men treated for metastatic prostate cancer between 2008-2014 and assessed initial presentation, categorizing patients into four groups. Groups 1 and 2 presented with localized disease and received treatment. These men suffered biochemical recurrence late (>1 year) or earlier (<1 year), respectively, and developed metastases. Groups 3 and 4 had asymptomatic and symptomatic metastases at the outset of their diagnosis. Patients with a first PSA at age 55 or younger were considered to have guideline-directed screening. RESULTS: Complete records were available on 157 men for initial presentation and 155 men for PSA screening. Groups 1, 2, 3 and 4 included 27 (17%), 7 (5%), 69 (44%) and 54 (34%) patients, respectively. Twenty (13%) patients received guideline-directed PSA screening, 5/155 (3%) patients presented with metastases prior to age 55 with their first PSA, and 130/155 (84%) had their first PSA after age 55, of which 122/130 (94%) had metastasis at the time of diagnosis. CONCLUSION: Despite widespread screening, most men treated for metastatic prostate cancer at our institution presented with metastases rather than progressed after definitive treatment. Furthermore, 25 (16%) patients received guideline-directed PSA screening at or before age 55. These data highlight that, despite mass screening efforts, patients treated for incurable disease at our institution may not have been a result of a failed screening test, but a failure to be screened.

Glycogen synthase kinase-3: a potential preventive target for prostate cancer management.

OBJECTIVES: Prostate cancers are the frequently diagnosed cancers in men, and patients with metastatic disease only have 28% chance for 5-year survival. Patients with low-risk tumors are subjected to active surveillance, whereas high-risk cases are actively treated. Unfortunately, there is no cure for patients with late-stage disease. Glycogen synthase kinase-3 (GSK-3, α and ß) is a protein serine/threonine kinase and has diverse cellular functions and numerous substrates. We sought to summarize all the studies done with GSK-3 in prostate cancers and to provide a prospective direction for future work. METHODS AND MATERIALS: A comprehensive search of the literature on the electronic databases PubMed was conducted for the subject terms of GSK-3 and prostate cancer. Gene mutation and expression information was extracted from Oncomine and COSMIC databases. Case reports were not included. RESULTS: Accumulating evidence indicates that GSK-3α is mainly expressed in low-risk prostate cancers and is related to hormone-dependent androgen receptor (AR)-mediated gene expression, whereas GSK-3ß is mainly expressed in high-risk prostate cancers and is related to hormone-independent AR-mediated gene expression. GSK-3 has been demonstrated as a positive regulator in AR transactivation and prostate cancer growth independent of the Wnt/ß-catenin pathway. Different types of GSK-3inhibitors including lithium show promising results in suppressing tumor growth in different animal models of prostate cancer. Importantly, clinical use of lithium is associated with reduced cancer incidence in psychiatric patients. CONCLUSIONS: Taken together, GSK-3 inhibition might be implicated in prostate cancer management as a preventive treatment.

Cav1.3 channel α1D protein is overexpressed and modulates androgen receptor transactivation in prostate cancers.

Widespread use of L-type calcium channel blockers for treating hypertension has led to multiple epidemiologic studies to assess the risk of prostate cancer incidence. These studies revealed a reverse correlation between the likelihood of prostate cancer risk and the use of L-type calcium channel blockers among men without family history but the mechanism was not clear. In this study, we examined the expression profiles of multiple L-type calcium channel genes in prostate cancers and determined their functional roles in androgen receptor (AR) transactivation and cell growth. By reanalyzing the ONCOMINE database, we found that L-type calcium channel CACNA1D gene expression levels in cancer tissues were significantly higher than noncancer tissues in 14 of 15 published complementary deoxyribonucleic acid microarray data sets, of which 9 data sets showed an increase of 2- to 17-folds. Quantitative polymerase chain reaction and immunostaining experiments revealed that CACNA1D gene and its coding protein α1D were highly expressed in prostate cancers, especially in castration-resistant diseases, compared with benign prostate tissues. Consistent with the notion of CACNA1D as an ERG-regulated gene, CACNA1D gene expression levels were significantly higher in prostate cancers with TMPRSS2-ERG gene fusion compared with the cases without this gene fusion. Blocking L-type channel's function or knocking down CACNA1D gene expression significantly suppressed androgen-stimulated Ca(2+) influx, AR transactivation, and cell growth in prostate cancer cells. Taken together, these data suggest that CACNA1D gene overexpression is associated with prostate cancer progression and might play an important role in Ca(2+) influx, AR activation, and cell growth in prostate cancer cells.

Adeno-associated virus-delivered short hairpin-structured RNA for androgen receptor gene silencing induces tumor eradication of prostate cancer xenografts in nude mice: a preclinical study.

The androgen receptor (AR) is the most critical factor in prostate cancer progression. We previously demonstrated that silencing the AR using 2 unique small interfering RNAs (no. 8 and no. 31 AR siRNA) induces apoptotic cell death in AR-positive prostate cancer cells. To develop this AR siRNA technique into a therapy for prostate cancers, we generated an adeno-associated virus (AAV) vector to stably express a short hairpin-structured RNA (shRNA) against the AR gene in vivo. In addition to the no. 8 AR shRNA (ARHP8), we also screened a group of AR shRNAs with different sequences and identified a less effective AR shRNA (ARHP4) that was used as an shRNA control. An empty AAV vector (AAV-GFP) was used as a negative control. Intratumoral injection of AAV-ARHP8 viruses significantly suppressed tumor growth of xenografts derived from either androgen-responsive or castration-resistant prostate cancer cells. Most interestingly, systemic delivery of the AAV-ARHP8 but not AAV-ARHP4 or AAV-GFP viruses via tail vein injection eliminated xenografts within 10 days. Further analysis revealed that AAV-ARHP8 viruses dramatically reduced the expression of AR-regulated cellular survival genes and caused a dramatic apoptotic response. Taken together, our data strongly suggest that AAV-ARHP8 viruses induced a strong AR gene silencing in vivo and that systemic delivery of ARHP8 siRNA via an AAV vector or any other means might be considered as novel gene therapy for prostate cancers.