Molecular pathogenesis of human prostate basal cell hyperplasia

The Molecular Biology of Prostate Cancer Stem Cells: From the Past to the Future

Prostate cancer (PCa) continues to rank as the second leading cause of cancer-related mortality in western countries, despite the golden treatment using androgen deprivation therapy (ADT) or anti-androgen therapy. With decades of research, scientists have gradually realized that the existence of prostate cancer stem cells (PCSCs) successfully explains tumor recurrence, metastasis and therapeutic failure of PCa. Theoretically, eradication of this small population may improve the efficacy of current therapeutic approaches and prolong PCa survival. However, several characteristics of PCSCs make their diminishment extremely challenging: inherent resistance to anti-androgen and chemotherapy treatment, over-activation of the survival pathway, adaptation to tumor micro-environments, escape from immune attack and being easier to metastasize. For this end, a better understanding of PCSC biology at the molecular level will definitely inspire us to develop PCSC targeted approaches. In this review, we comprehensively summarize signaling pathways responsible for homeostatic regulation of PCSCs and discuss how to eliminate these fractional cells in clinical practice. Overall, this study deeply pinpoints PCSC biology at the molecular level and provides us some research perspectives.

Administration of Caesalpinia bonduc Seed Extracts Ameliorates Testosterone-Induced Benign Prostatic Hyperplasia (BPH) in Male Wistar Rats

Introduction

Benign prostatic hyperplasia (BPH) is a major chronic disease affecting men, and the therapeutic agents currently used to manage it have significant side effects. As a result, an alternative medicine with improved therapeutic properties with no side effects is desperately needed. The current investigation aims to study whether the Caesalpinia bonduc seed extracts (ethanolic-A, hydroalcoholic-B, and aqueous-C) have inhibitory potential on testosterone propionate (TP)-induced BPH in Wistar rats.

Methods

Wistar rats (male) were randomly allocated to one of five groups: control, BPH (TP-3 mg/kg, subcutaneously daily), low dose (TP + C. bonduc seed extracts – 200 mg/kg body weight), high dose (TP + C. bonduc seed extracts – 400 mg/kg body weight), and standard drug (TP + finasteride – 10 mg/kg body weight). At the end of drug treatment, the rats were sacrificed and their serum and prostates were taken for biochemical and histological studies.

Results

C. bonduc seed extracts treatment significantly decreased prostate weight and prostatic index in rats with TP-induced BPH. The seed extracts exhibited a potent inhibitory effect on dihydrotestosterone (DHT) in serum and prostate. In addition, the PSA level in the serum showed a noteworthy decrease in comparison with the BPH group. Histopathological examination also indicated that extracts improved the tissue morphology of the prostate significantly. Out of three extracts tested, ethanolic and hydroalcoholic extract recorded significant effect. Finally, liquid chromatography quadrupole time-of-flight mass spectrometry (LC/MS-QTOF) analysis showed that the major compounds present in the extracts were tocopherols, fucosterol, linoleic acid, β-amyrin, β-sitosterol, campesterol, cassane furanoditerpene, norcassane furanoditerpene and other diterpenes.

Conclusion

Thus, C. bonduc seed extracts could be a potential source for the formulation of new drug for managing BPH. To the best of our knowledge, this is the first scientific animal investigation into the use of C. bonduc seed extract for the management of BPH.

High Keratin-7 Expression in Benign Peri-Tumoral Prostatic Glands Is Predictive of Bone Metastasis Onset and Prostate Cancer-Specific Mortality

BACKGROUND

New predictive biomarkers are needed to accurately predict metastasis-free survival (MFS) and cancer-specific survival (CSS) in localized prostate cancer (PC). Keratin-7 (KRT7) overexpression has been associated with poor prognosis in several cancers and is described as a novel prostate progenitor marker in the mouse prostate.

METHODS

KRT7 expression was evaluated in prostatic cell lines and in human tissue by immunohistochemistry (IHC, on advanced PC, n = 91) and immunofluorescence (IF, on localized PC, n = 285). The KRT7 mean fluorescence intensity (MFI) was quantified in different compartments by digital analysis and correlated to clinical endpoints in the localized PC cohort.

RESULTS

KRT7 is expressed in prostatic cell lines and found in the basal and supra-basal compartment from healthy prostatic glands and benign peri-tumoral glands from localized PC. The KRT7 staining is lost in luminal cells from localized tumors and found as an aberrant sporadic staining (2.2%) in advanced PC. In the localized PC cohort, high KRT7 MFI above the 80th percentile in the basal compartment was significantly and independently correlated with MFS and CSS, and with hypertrophic basal cell phenotype.

CONCLUSION

High KRT7 expression in benign glands is an independent biomarker of MFS and CSS, and its expression is lost in tumoral cells. These results require further validation on larger cohorts.

Smoking Is Associated With Basal Cell Hyperplasia on Prostate Biopsy Specimens

OBJECTIVES

To the best of our knowledge, no study has analyzed the association between cigarette smoking and prostate basal cell proliferation. Therefore, we sought to evaluate whether smoking status is associated with the presence of basal cell hyperplasia (BCH).

METHODS

We performed a retrospective analysis of 8,196 men aged 50 to 75 years with prostate-specific antigen values between 2.5 µg/mL and 10 µg/mL and prior negative biopsy who were enrolled in the (REDUCE) trial. Cigarette smoking status was divided into current, former, or never categories at enrollment. The association between smoking and baseline BCH was evaluated, with logistic regression in univariable and multivariable analysis.

RESULTS

A total of 1,233 (15.1%) men were current smokers, 3,206 (39.1%) were former smokers, and 3,575 (45.8%) were never smokers. In univariable analysis, current smoking was associated with higher baseline BCH occurrence compared with never (odds ratio [OR], 1.87; 95% confidence interval [CI], 1.14-3.10) and former smokers (OR, 1.77; 95% CI, 1.06-2.95). Similar results were found after adjusting for patient characteristics (current vs never smokers: OR, 1.92; 95% CI, 1.14-3.26; current vs former smokers: OR, 1.71; 95% CI, 1.01-2.91).

CONCLUSIONS

Among men undergoing prostate biopsy, all of whom had a negative biopsy result, current smoking at enrollment was independently associated with BCH in standard peripheral zone prostate biopsies.

Mutational and transcriptomic landscapes of a rare human prostate basal cell carcinoma

BACKGROUND

As a rare subtype of prostate carcinoma, basal cell carcinoma (BCC) has not been studied extensively and thus lacks systematic molecular characterization.

METHODS

Here, we applied single-cell genomic amplification and RNA-Seq to a specimen of human prostate BCC (CK34βE12⁺ /P63⁺ /PAP^- /PSA^- ). The mutational landscape was obtained via whole exome sequencing of the amplification mixture of 49 single cells, and the transcriptomes of 69 single cells were also obtained.

RESULTS

The five putative driver genes mutated in BCC are CASC5, NUTM1, PTPRC, KMT2C, and TBX3, and the top three nucleotide substitutions are C>T, T>C, and C>A, similar to common prostate cancer. The distribution of the variant allele frequency values indicated that these single cells are from the same tumor clone. The 69 single cells were clustered into tumor, stromal, and immune cells based on their global transcriptomic profiles. The tumor cells specifically express basal cell markers like KRT5, KRT14, and KRT23 and epithelial markers EPCAM, CDH1, and CD24. The transcription factor covariance network analysis showed that the BCC tumor cells have distinct regulatory networks. By comparison with current prostate cancer datasets, we found that some of the bulk samples exhibit basal cell signatures. Interestingly, at single-cell resolution the gene expression patterns of prostate BCC tumor cells show uniqueness compared with that of common prostate cancer-derived circulating tumor cells.

CONCLUSIONS

This study, for the first time, discloses the comprehensive mutational and transcriptomic landscapes of prostate BCC, which lays a foundation for the understanding of its tumorigenesis mechanism and provides new insights into prostate cancers in general.

Distinct expression patterns of SULT2B1b in human prostate epithelium

BACKGROUND

SULT2B1b (sulfotransferase family cytosolic 2B member 1b) catalyzes the sulfate conjugation of substrates such as cholesterol and oxysterols. Our laboratory has previously shown that SULT2B1b inhibition modulates androgen receptor signaling and induces apoptosis in prostate cancer cells. However, the functions of SULT2B1b in the prostate remain poorly understood.

METHODS

We characterized the expression pattern of SULT2B1b in human benign prostate hyperplasia (BPH) as well as prostate cancer to determine the relationship between SULT2B1b and prostate diseases, using immunohistochemistry, immunofluorescence staining, immunoblot, and real-time polymerase chain reaction.

RESULTS

SULT2B1b was strongly detected in the prostate epithelium but was absent in the stroma. Significantly lower SULT2B1b was found in primary cancer cells compared with adjacent normal epithelial cells. SULT2B1b further decreased in metastatic cancer cells. Most interestingly, we found, for the first time, that SULT2B1b was much more concentrated in the luminal layer than in the basal layer in both normal prostate and BPH samples. The stronger presence of SULT2B1b in luminal epithelial cells was confirmed by costaining with luminal and basal markers and in sorted paired luminal and basal cells. SULT2B1b expression was induced with prostate organoid differentiation.

CONCLUSIONS

SULT2B1b inversely correlates with prostate cancer status, with the highest level in the normal epithelium and lowest in the advanced metastatic prostate cancer. Furthermore, SULT2B1b is mostly located within the luminal layer of the prostate epithelium, suggesting that it may be implicated in luminal differentiation.

Potential repositioning of GV1001 as a therapeutic agent for testosterone‑induced benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is one of the leading causes of male reproductive disorders. Therapeutic agents currently in use have severe side effects; therefore, alternative drugs that exhibit improved therapeutic activity without side effects are required. The present study investigated the protective effect of GV1001 against testosterone‑induced BPH in rats. BPH in castrated rats was established via daily subcutaneous (s.c.) injections of testosterone propionate (TP, 3 mg/kg) dissolved in corn oil for 4 weeks. GV1001 (0.01, 0.1 and 1 mg/kg, s.c.) was administered 3 times per week for 4 weeks, together with TP (3 mg/kg) injection. The rats were sacrificed on the last day of treatment, and their prostates were excised and weighed for biochemical and histological studies. Serum levels of testosterone and dihydrotestosterone (DHT) were also measured. In rats with TP‑induced BPH, a significant increase in prostate weight (PW) and prostatic index (PI), accompanied by a decrease in antioxidant enzyme activity, was observed. Histological studies revealed clearly enlarged glandular cavities in rats with BPH. GV1001 (0.01 and 0.1 mg/kg) treatment significantly decreased PW and PI in rats with TP‑induced BPH. In addition, GV1001 demonstrated a potent inhibitory effect on 5α‑reductase in prostate. The present data suggest that the protective role of GV1001 against testosterone‑induced BPH is closely associated with its antioxidant potential. Additional studies are required to identify the mechanisms by which GV1001 protects against BPH to determine its clinical application.