Inhibition of NF-kappa B signaling restores responsiveness of castrate-resistant prostate cancer cells to anti-androgen treatment by decreasing androgen receptor-variant expression.

Androgen receptor splicing variants (ARVs) that lack the ligand-binding domain (LBD) are associated with the development of castration-resistant prostate cancer (CRPC), including resistance to the new generation of high-affinity anti-androgens. However, the mechanism by which ARV expression is regulated is not fully understood. In this study, we show that the activation of classical nuclear factor-kappa B (NF-κB) signaling increases the expression of ARVs in prostate cancer (PCa) cells and converts androgen-sensitive PCa cells to become androgen-insensitive, whereas downregulation of NF-κB signaling inhibits ARV expression and restores responsiveness of CRPC to anti-androgen therapy. In addition, we demonstrated that combination of anti-androgen with NF-κB-targeted therapy inhibits efficiently tumor growth of human CRPC xenografts. These results indicate that induction of ARVs by activated NF-κB signaling in PCa cells is a critical mechanism by which the PCa progresses to CRPC. This has important implications as it can prolong the survival of CRPC patients by restoring the tumors to once again respond to conventional androgen-deprivation therapy (ADT).

SOX2 expression in the developing, adult, as well as, diseased prostate.

BACKGROUND: SOX2 is a member of SOX (SRY-related high mobility group box) family of transcription factors. METHODS: In this study, we examined the expression of SOX2 in murine and human prostatic specimens by immunohistochemistry. RESULTS: We found that SOX2 was expressed in murine prostates during budding morphogenesis and in neuroendocrine (NE) prostate cancer (PCa) murine models. Expression of SOX2 was also examined in human prostatic tissue. We found that SOX2 was expressed in 26 of the 30 BPH specimens. In these BPH samples, expression of SOX2 was limited to basal epithelial cells. In contrast, 24 of the 25 primary PCa specimens were negative for SOX2. The only positive primary PCa was the prostatic NE tumor, which also showed co-expression of synaptophysin. Additionally, the expression of SOX2 was detected in all prostatic NE tumor xenograft lines. Furthermore, we have examined the expression of SOX2 on a set of tissue microarrays consisting of metastatic PCa tissues. Expression of SOX2 was detected in at least one metastatic site in 15 of the 24 patients with metastatic castration-resistant PCa; and the expression of SOX2 was correlated with synaptophysin. CONCLUSIONS: SOX2 was expressed in developing prostates, basal cells of BPH, as well as prostatic NE tumors.

PPARγ isoforms differentially regulate metabolic networks to mediate mouse prostatic epithelial differentiation.

Recent observations indicate prostatic diseases are comorbidities of systemic metabolic dysfunction. These discoveries revealed fundamental questions regarding the nature of prostate metabolism. We previously showed that prostate-specific ablation of PPARγ in mice resulted in tumorigenesis and active autophagy. Here, we demonstrate control of overlapping and distinct aspects of prostate epithelial metabolism by ectopic expression of individual PPARγ isoforms in PPARγ knockout prostate epithelial cells. Expression and activation of either PPARγ 1 or 2 reduced de novo lipogenesis and oxidative stress and mediated a switch from glucose to fatty acid oxidation through regulation of genes including Pdk4, Fabp4, Lpl, Acot1 and Cd36. Differential effects of PPARγ isoforms included decreased basal cell differentiation, Scd1 expression and triglyceride fatty acid desaturation and increased tumorigenicity by PPARγ1. In contrast, PPARγ2 expression significantly increased basal cell differentiation, Scd1 expression and AR expression and responsiveness. Finally, in confirmation of in vitro data, a PPARγ agonist versus high-fat diet (HFD) regimen in vivo confirmed that PPARγ agonization increased prostatic differentiation markers, whereas HFD downregulated PPARγ-regulated genes and decreased prostate differentiation. These data provide a rationale for pursuing a fundamental metabolic understanding of changes to glucose and fatty acid metabolism in benign and malignant prostatic diseases associated with systemic metabolic stress.

Identification of stromally expressed molecules in the prostate by tag-profiling of cancer-associated fibroblasts, normal fibroblasts and fetal prostate.

The stromal microenvironment has key roles in prostate development and cancer, and cancer-associated fibroblasts (CAFs) stimulate tumourigenesis via several mechanisms including the expression of pro-tumourigenic factors. Mesenchyme (embryonic stroma) controls prostate organogenesis, and in some circumstances can re-differentiate prostate tumours. We have applied next-generation Tag profiling to fetal human prostate, normal human prostate fibroblasts (NPFs) and CAFs to identify molecules expressed in prostatic stroma. Comparison of gene expression profiles of a patient-matched pair of NPFs vs CAFs identified 671 transcripts that were enriched in CAFs and 356 transcripts whose levels were decreased, relative to NPFs. Gene ontology analysis revealed that CAF-enriched transcripts were associated with prostate morphogenesis and CAF-depleted transcripts were associated with cell cycle. We selected mRNAs to follow-up by comparison of our data sets with published prostate cancer fibroblast microarray profiles as well as by focusing on transcripts encoding secreted and peripheral membrane proteins, as well as mesenchymal transcripts identified in a previous study from our group. We confirmed differential transcript expression between CAFs and NPFs using QrtPCR, and defined protein localization using immunohistochemistry in fetal prostate, adult prostate and prostate cancer. We demonstrated that ASPN, CAV1, CFH, CTSK, DCN, FBLN1, FHL1, FN, NKTR, OGN, PARVA, S100A6, SPARC, STC1 and ZEB1 proteins showed specific and varied expression patterns in fetal human prostate and in prostate cancer. Colocalization studies suggested that some stromally expressed molecules were also expressed in subsets of tumour epithelia, indicating that they may be novel markers of EMT. Additionally, two molecules (ASPN and STC1) marked overlapping and distinct subregions of stroma associated with tumour epithelia and may represent new CAF markers.

Perspectives on tissue interactions in development and disease.

From the morphogenetic movements of the three germ layers during development to the reactive stromal microenvironment in cancer, tissue interactions are vital to maintaining healthy organ morphologic architecture and function. The stromal compartment is thought to be complicit in tumor progression and, as such, represents an opportune target for disease therapies. However, recent developments in our understanding of the diversity of the stromal compartment and the lack of appropriate models to study its relevance in human disease have limited our further understanding of the role of tissue interactions in tumor progression. The failure any model to fully recapitulate the complexities of systemic biology continue to create a higher imperative for incorporating various perspectives into a broader understanding for the ultimate goal of designing interventional therapies. Understanding this potential, this review examines the biological models used to study stromal-epithelial interactions and includes an attempt to incorporate behavioral terminology to define and mathematically model ecological relationships in stromal-epithelial interactions. In addition, the current attempt to incorporate these diverse ecological perspectives into in silico mathematical models through cross-disciplinary coordination is reviewed, which will provide a fresh perspective on defining cell group behavior and tissue ecology in disease and hopefully lead to the generation of new hypotheses to be empirically validated.

Pim1 kinase synergizes with c-MYC to induce advanced prostate carcinoma.

The oncogenic PIM1 kinase has been implicated as a cofactor for c-MYC in prostate carcinogenesis. In this study, we show that in human prostate tumors, coexpression of c-MYC and PIM1 is associated with higher Gleason grades. Using a tissue recombination model coupled with lentiviral-mediated gene transfer we find that Pim1 is weakly oncogenic in naive adult mouse prostatic epithelium. However, it cooperates dramatically with c-MYC to induce prostate cancer within 6-weeks. Importantly, c-MYC/Pim1 synergy is critically dependent on Pim1 kinase activity. c-MYC/Pim1 tumors showed increased levels of the active serine-62 (S62) phosphorylated form of c-MYC. Grafts expressing a phosphomimetic c-MYCS62D mutant had higher rates of proliferation than grafts expressing wild type c-MYC but did not form tumors like c-MYC/Pim1 grafts, indicating that Pim1 cooperativity with c-MYC in vivo involves additional mechanisms other than enhancement of c-MYC activity by S62 phosphorylation. c-MYC/Pim1-induced prostate carcinomas show evidence of neuroendocrine (NE) differentiation. Additional studies, including the identification of tumor cells coexpressing androgen receptor and NE cell markers synaptophysin and Ascl1 suggested that NE tumors arose from adenocarcinoma cells through transdifferentiation. These results directly show functional cooperativity between c-MYC and PIM1 in prostate tumorigenesis in vivo and support efforts for targeting PIM1 in prostate cancer.

Mitogen-activated protein kinase pathway is involved in alpha6 integrin gene expression in androgen-independent prostate cancer cells: role of proximal Sp1 consensus sequence.

Metastatic diseases of prostate cancer reveal high expression of alpha6 integrin and the activation of mitogen-activated protein kinases (MAP kinase). Therefore, the present study was conducted to examine whether MAP kinase pathway is involved in the alpha6 integrin gene expression in androgen-independent prostate cancer cell lines. alpha6 integrin mRNA expression, the alpha6 integrin promoter-induced luciferase activities and MAP kinase enzyme activities in androgen-independent LNCaP and PC-3 cell lines were higher than those in androgen-dependent LNCaP. Deletion and mutation analysis showed that Sp1 consensus sequence at -48 to -43 bp from the transcription start site was necessary for basal promoter activity. Binding of Sp1 to its consensus sequence in three cell lines was confirmed by electrophoretic mobility shift assays. Sp1 binding to its consensus sequence, as well as promoter activity and mRNA expression, were found to be inhibited by an inhibitor of MAP kinase kinase 1 and 2, U0126, in the androgen-independent cell lines. Our results indicate that the proximal Sp1 is necessary for basal promoter activity of the alpha6 integrin, suggesting that signal transduction from MAP kinases to activation of Sp1 might be involved in alpha6 integrin gene expression in androgen-independent prostate cancer cell lines.

p27Kip1 is the key mediator of phenylacetate induced cell cycle arrest in human prostate cancer cells.

Treatment with millimolar concentrations of phenylacetate (PA), results in cytostasis, growth inhibition and differentiation in several human cancer cell lines, including prostate cancer. However, the molecular basis of PA-induced biological effects has not been elucidated in detail. In this study we focused on its influence on cell cycle events and investigated alterations in cell cycle regulators in androgen-dependent and independent human prostate cancer cell lines. FACS analysis revealed that suppression of cell growth by PA was due to G1 arrest, with reduced phosphorylation of the retinoblastoma protein (pRb) and CDK2 activity. Expression of p27Kip1 was increased, while p21Cip1, p53, cyclinD1 and cyclin E were not affected by PA. Binding of p27Kip1 to CDK2 increased significantly following treatment with PA. Furthermore, antisense p27Kip1 oligonucleotide attenuated the inhibitory effect of PA. Our results suggested that p27Kip1 might be a critical target in PA-mediated cell growth arrest in prostate cancer cells playing a key role in CDK2 inactivation followed by hypophosphorylation of pRB and subsequent G1 cell cycle arrest.

The usefulness of power Doppler ultrasonography for diagnosing prostate cancer: histological correlation of each biopsy site.

OBJECTIVE: To correlate the findings of power Doppler ultrasonography (PDUS) of the prostate with those of site-specific transrectal ultrasonography (TRUS)-guided biopsy. PATIENTS AND METHODS: The study comprised 28 patients referred to our institution for TRUS-guided prostate biopsy because of an elevated PSA level and/or abnormal digital rectal examination. PDUS findings were graded 0, 1 or 2; grades 0-1 were considered as negative and grade 2 as positive. The blood volume of each biopsy site was also determined using the mean number (MN) value that represents the average vascularity in a 5-mm square sample. PDUS values were correlated with the histological findings of 147 biopsies with 19 focal lesions. RESULTS: Grade 2 was assigned to 19 sites, grade 1 to 52 sites, and grade 0 to 76 sites. Fourteen of the 19 PDUS findings of grade 2 sites revealed carcinoma and five were grade 1. Ten of 35 TRUS-positive sites were carcinomas, three benign prostatic hyperplasia (BPH) and 22 normal. The MN value for prostatic carcinoma was 4.33, for BPH 11.7 and for normal tissue 4.7. The overall sensitivity of PDUS was 74%, the specificity 96% and the positive predictive value 74%. CONCLUSIONS: Because TRUS alone cannot detect all cancers, PDUS should be used routinely in all patients undergoing TRUS-guided biopsy, to improve the diagnostic yield of prostate cancer.

[Clinical study of prostate cancer: statistical analysis of 107 cases in the past 12 years].

One hundred and seven patients with prostate cancer were treated at Mie University Hospital during the past 12 years between 1988 and 1999. They were between 53 and 83 years old, with an average age of 70.8 years old. The clinical stage was defined as A, B, C and D in 3 (2.8%), 19 (17.8%), 50 (46.7%) and 35 (32.7%) patients, respectively. At initial diagnosis, the tumor was well, moderately and poorly differentiated adenocarcinoma in 26 (24.3%), 47 (43.9%) and 34 (31.8%) patients, respectively. The median follow-up period was 52.3 months. The overall 1, 3 and 5-year survival rates were 98.0%, 86.8% and 75.2%, respectively. The 5-year survival rates for stage A, B, C and D were 100%, 93.8%, 82.1% and 56.9%, respectively. A significant difference (p = 0.017) in 5-year survival rate was noted between stage C and D. The 5-year survival rate was 100% for well differentiated, 78.0% for moderately differentiated, and 53.2% for poorly differentiated adenocarcinoma. A significant difference (p = 0.0016) in the 5-year survival rate was noted between well differentiated and poorly differentiated adenocarcinoma. According to the therapy, the 5-year survival rate in stage C was 86.2% for the radical prostatectomy group and 84.0% for the endocrine therapy group. There was no significant difference between these 2 treatment groups. Endocrine therapies, classified into maximum androgen blockade (MAB) and endocrine therapy other than MAB were performed for stage D as an initial therapy. Although the prognosis in the patients treated with MAB was better than that with other endocrine therapies, there was no significant difference between these 2 endocrine treatment groups.

[Abnormal hemoglobins in a Negroid population in Peru]. / Estudio de hemoglobinas anormales en una población de raza negra en el Perú.

A study was performed on 100 blood samples from black people native of the Chincha province and living in Pueblo Nuevo Ica district, in Peru. No haematological abnormalities were seen in any of the cases. Upon haemoglobin electrophoresis, 8 carriers of abnormal haemoglobin were found, the A/S pattern appearing in 5 instances and the A/C pattern in 3. These 8 samples were subjected to deoxyhaemoglobin solubility tests and to differential solubility test with urea, the initial results being confirmed. These data correlate, in general terms with previous findings.