Patient-derived castration-resistant prostate cancer model revealed CTBP2 upregulation mediated by OCT1 and androgen receptor.

BACKGROUND: Prostate cancer is dependent on androgen receptor (AR) signaling, and androgen deprivation therapy (ADT) has proven effective in targeting prostate cancer. However, castration-resistant prostate cancer (CRPC) eventually emerges. AR signaling inhibitors (ARSI) have been also used, but resistance to these agents develops due to genetic AR alterations and epigenetic dysregulation. METHODS: In this study, we investigated the role of OCT1, a member of the OCT family, in an AR-positive CRPC patient-derived xenograft established from a patient with resistance to ARSI and chemotherapy. We conducted a genome-wide analysis chromatin immunoprecipitation followed by sequencing and bioinformatic analyses using public database. RESULTS: Genome-wide analysis of OCT1 target genes in PDX 201.1 A revealed distinct OCT1 binding sites compared to treatment-naïve cells. Bioinformatic analyses revealed that OCT1-regulated genes were associated with cell migration and immune system regulation. In particular, C-terminal Binding Protein 2 (CTBP2), an OCT1/AR target gene, was correlated with poor prognosis and immunosuppressive effects in the tumor microenvironment. Metascape revealed that CTBP2 knockdown affects genes related to the immune response to bacteria. Furthermore, TISIDB analysis suggested the relationship between CTBP2 expression and immune cell infiltration in prostate cancer, suggesting that it may contribute to immune evasion in CRPC. CONCLUSIONS: Our findings shed light on the genome-wide network of OCT1 and AR in AR-positive CRPC and highlight the potential role of CTBP2 in immune response and tumor progression. Targeting CTBP2 may represent a promising therapeutic approach for aggressive AR-positive CRPC. Further validation will be required to explore novel therapeutic strategies for CRPC management.

Association Between Frailty and Pelvic Organ Prolapse in Elderly Women: A Retrospective Study.

INTRODUCTION AND HYPOTHESIS: This study evaluated the association between pelvic organ prolapse (POP), frailty, and sarcopenia to explore how POP treatment can extend healthy life expectancy in elderly women. METHODS: We conducted a retrospective study of prospectively collected data, comparing women with mild POP (stages 0-II) with those with advanced POP (stages III and IV). The inclusion criteria for this study were women who visited the clinic with at least one symptom of pelvic floor dysfunction and underwent imaging studies between April 2020 and November 2022. Initially, 119 patients met these inclusion criteria. Patients were excluded if they had a history of previous POP treatment, did not respond to the study survey, or were lost to follow-up. After applying these exclusion criteria, 82 patients were included in the final analysis, of whom 65 underwent surgery (laparoscopic sacrocolpopexy, colpocleisis, tension-free vaginal tape, and native tissue repair). Assessments included POP Quantification, Kihon Checklist, Pelvic Organ Prolapse Quality of Life (P-QOL) questionnaire, International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score (OABSS), and Incontinence Symptom Questionnaire (ICIQ-SF). Pelvic muscles were measured using MRI or CT. Immunohistochemical analysis of estrogen receptor alpha (ERα), estrogen receptor beta , and androgen receptor was performed on surgical specimens from 43 patients. RESULTS: The median age of participants was 75 years. Of the 82 patients, 48 (58.5%) were classified as frail or pre-frail, and 22 (26.8%) exhibited motor impairment. Advanced POP (stages 3 and 4) was seen in 41 patients. These patients had more motor function impairments (advanced, 16; mild, 6; p = 0.01). Patients with advanced POP had poorer P-QOL, ICIQ-SF (median: 9.5 vs 4, p = 0.006) and OABSS (7 vs 4, p = 0.008) scores, and smaller pubococcygeus muscle diameter (2.5 vs 3 cm, p = 0.017). Postoperatively, significant improvements were seen in P-QOL (all domains except personal relationships: p < 0.001), total IPSS (11 vs 4, p < 0.001), OABSS (6 vs 5, p = 0.033), and ICIQ-SF scores (6 vs 2, p < 0.001). ERα expression was associated with preoperative frailty (r = -0.37, p = 0.014). CONCLUSIONS: Advanced POP correlates with poorer QOL, worse urinary symptoms, and reduced pubococcygeus muscle diameter, consistent with sarcopenia, compared with mild POP.

Exploring androgen receptor signaling pathway in prostate cancer: A path to new discoveries.

Androgen deprivation therapy has achieved significant success in treating prostate cancer through strategies centered on the androgen receptor. However, the emergence of castration-resistant prostate cancer highlights this therapy limitation, underscoring the need to elucidate the mechanisms of treatment resistance. This review aimed to focus on multifaceted resistance mechanisms, including androgen receptor overexpression, splice variants, missense mutations, the involvement of the glucocorticoid receptor, and alterations in coregulators and transcription factors, revealing their roles in castration-resistant prostate cancer progression. These mechanisms promote cell survival and proliferation, depending on the androgen receptor signaling pathway, leading to resistance to conventional therapies. Amplification and mutations in the androgen receptor gene facilitate selective adaptation in treatment-resistant cells, consequently diminishing therapeutic efficacy. Furthermore, the activation of glucocorticoid receptors and aberrant regulation of specific coregulators and transcription factors contribute to the activation of androgen receptor-independent signaling pathways, promoting cell survival and proliferation. These findings hold promise for identifying new targets for treating castration-resistant prostate cancer and developing personalized treatment strategies. The development of future therapies will hinge on precisely targeting the androgen receptor signaling pathway, necessitating a deeper understanding of the molecular targets unique to castration-resistant prostate cancer.

Recent advances in basic research on prostate cancer: Where we are heading?

In the over 80 years since androgens were found to play a pivotal role in prostate cancer (PCa) progression, androgen deprivation therapy (ADT) has been a cornerstone in treating advanced PCa. Castration-resistant PCa persists, however, with some of these tumors evolving to androgen receptor (AR)-independent forms like neuroendocrine PCa. The development of novel diagnostic and therapeutic approaches to PCa is therefore crucial. This review provides an overview of recent basic research in PCa, focusing on two main areas: PCa cells and their tumor microenvironments. The first section describes current knowledge on the intricate mechanisms of AR signaling pathways, emphasizing the roles of coactivators and chromatin state alterations in gene regulation. Genomic analyses have revealed recurrent mutations and copy number alterations critical for precision medicine. Liquid biopsy has become a promising tool for real-time tumor monitoring, identifying genetic alterations in circulating-tumor DNA or extracellular vesicles. The second section describes the tumor microenvironment of PCa, highlighting its immunosuppressive landscape and the potential of combining ADT with immunotherapy. Advanced techniques, including single-cell RNA sequencing and spatial transcriptomics offer insights into cellular heterogeneity and interactions within the tumor microenvironment, paving the way for novel therapeutic strategies. Integration of these diverse research areas will provide a comprehensive understanding of the current state and future directions of PCa research, underscoring the importance of personalized medicine and the dynamic nature of cancer treatment strategies.

Initial experience with prostatic urethral lift versus enucleation of the prostate: a retrospective comparative study.

BACKGROUND: This study aimed to assess initial results and patient characteristics of prostatic urethral lift (PUL) compared with those of bipolar transurethral enucleation of the prostate (TUEB) in the treatment of benign prostatic hyperplasia (BPH) in older patients. METHODS: This retrospective study was conducted at a single institution and involved 25 consecutive patients with BPH who underwent PUL between April 2022 and May 2023. Patient characteristics, operative details, and pre- and postoperative symptom scores were evaluated. The results were compared with those of a previously reported TUEB group (n = 55). RESULTS: The mean age of the patients in the PUL group was 74.6 years, and the mean prostate volume was 47.5 ml. The PUL procedure significantly improved urinary symptoms, particularly incomplete emptying (p = 0.041), intermittency (p = 0.005), and weak stream (p = 0.001). The PUL group had higher comorbidity scores (p = 0.048) and included older patients (p = 0.002) than the TUEB group. TUEB showed better improvements in some symptoms and maximum flow rate (p = 0.01) than PUL; however, PUL had a shorter operative time and fewer complications than TUEB (p < 0.001). CONCLUSION: The initial results demonstrate the efficacy and safety of PUL in older patients with BPH. Despite TUEB showing better outcomes in certain aspects than PUL, PUL offers advantages such as shorter operative time and fewer complications. Therefore, PUL can be considered a viable option for high-risk older patients with BPH.

Clinical characteristics of patients with metastatic castration-resistant prostate cancer after treatment with combined androgen blockade.

BACKGROUND: Although the second-generation androgen receptor inhibitors and taxanes have recently been recommended for the initial treatment of metastatic prostate cancer, bicalutamide and flutamide are still used in a large number of cases. Therefore, it is important to elucidate the clinical characteristics of these treated CRPC cases and their sensitivity to the currently used therapeutic agents. We aimed to examine the outcomes of metastatic castration-resistant prostate cancer following combined androgen blockade as initial therapy at our institution. METHODS: Ninety-four patients who developed metastatic castration-resistant prostate cancer after hormonal treatment with combined nonsteroidal androgen receptor antagonists and continuous androgen deprivation therapy between January 2015 and December 2020 were included. The presence of visceral metastases, duration of efficacy of each treatment, and overall survival after castration-resistant prostate cancer were evaluated. RESULTS: Patients with a longer duration of castration-resistant prostate cancer tended to have a longer response duration to subsequent enzalutamide administration (p = 0.003). Patients who achieved a 90% reduction in prostate-specific antigen levels with enzalutamide had a significantly better castration-resistant prostate cancer prognosis (p = 0.002). Meanwhile, those with visceral metastases at the time of castration-resistant prostate cancer diagnosis had a significantly poorer prognosis (p < 0.001). A positive correlation was observed between the treatment efficacy of abiraterone and taxanes for castration-resistant prostate cancer. CONCLUSION: The study provides scientific evidence to support that patients with longer time to castration-resistant prostate cancer are more sensitive to enzalutamide, and the use of abiraterone between docetaxel and cabazitaxel has favorable prognostic impact. These findings provide instrumental evidence that can enable better treatment selection for prostate cancer patients.

Enfortumab vedotin versus platinum rechallenge in post-platinum, post-pembrolizumab advanced urothelial carcinoma: A multicenter propensity score-matched study.

OBJECTIVE: Enfortumab vedotin (EV) was approved for advanced urothelial carcinoma (UC) in 2021 after the EV-301 trial showed its superiority to non-platinum-based chemotherapy as later-line treatment after platinum-based chemotherapy and immune checkpoint inhibitors including pembrolizumab. However, no study has compared EV with rechallenging platinum-based chemotherapy (i.e., "platinum rechallenge") in that setting. METHODS: In total, 283 patients received pembrolizumab for advanced UC after platinum-based chemotherapy between 2018 and 2023. Of them, 41 and 25 patients received EV and platinum rechallenge, respectively, as later-line treatment after pembrolizumab. After excluding two patients with EV without imaging evaluation, we compared oncological outcomes, including progression-free survival (PFS) and overall survival (OS), between the EV (n = 39) and platinum rechallenge groups (n = 25) using propensity score matching (PSM). RESULTS: Analyses on crude data (n = 64) showed no significant differences between the two groups regarding patients' baseline characteristics. PFS (5 months) and OS (11 months) in the EV group were comparable to those (8 and 12 months, respectively) in the platinum rechallenge group. After PSM (n = 36), the baseline characteristics between the two groups became more balanced, and PFS (not reached) and OS (not reached) in the EV group were comparable to those (8 and 11 months, respectively) in the platinum rechallenge group. CONCLUSIONS: EV and platinum rechallenge showed equivalent oncological outcomes, even after PSM, and both treatments should therefore be effective treatment options for post-platinum, post-pembrolizumab advanced UC.

Antitumor effects of pyrrole-imidazole polyamide modified with alkylating agent on prostate cancer cells.

Androgens and androgen receptor (AR) have a central role in prostate cancer progression by regulating its downstream signaling. Although androgen depletion therapy (ADT) is the primary treatment for most prostate cancers, they acquires resistance to ADT and become castration resistant prostate cancers (CRPC). AR complex formation with multiple transcription factors is important for enhancer activity and transcriptional regulation, which can contribute to cancer progression and resistance to ADT. We previously demonstrated that OCT1 collaborates with AR in prostate cancer, and that a pyrrole-imidazole (PI) polyamide (PIP) targeting OCT1 inhibits cell and castration-resistant tumor growth (Obinata D et al. Oncogene 2016). PIP can bind to DNA non-covalently without a drug delivery system unlike most DNA targeted therapeutics. In the present study, we developed a PIP modified with a DNA alkylating agent, chlorambucil (ChB) (OCT1-PIP-ChB). Then its effect on the growth of prostate cancer LNCaP, 22Rv1, and PC3 cells, pancreatic cancer BxPC3 cells, and colon cancer HCT116 cells, as well as non-cancerous MCF-10A epithelial cells, were analyzed. It was shown that the IC50s of OCT1-PIP-ChB for 22Rv1 and LNCaP were markedly lower compared to other cells, including non-cancerous MCF-10A cells. Comprehensive gene expression analysis of CRPC model 22Rv1 cells treated with IC50 concentrations of OCT1-PIP-ChB revealed that the gene group involved in DNA double-strand break repair was the most enriched among gene sets repressed by OCT1-PIP-ChB treatment. Importantly, in vivo study using 22Rv1 xenografts, we showed that OCT1-PIP-ChB significantly reduced tumor growth compared to the control group without showing obvious adverse effects. Thus, the PIP combined with ChB can exert a significant inhibitory effect on prostate cancer cell proliferation and castration-resistant tumor growth, suggesting a potential role as a therapeutic agent.

Improved survival in real-world patients with advanced urothelial carcinoma: A multicenter propensity score-matched cohort study comparing a period before the introduction of pembrolizumab (2003-2011) and a more recent period (2016-2020).

OBJECTIVES: Although the treatment strategy for advanced urothelial carcinoma (aUC) has drastically changed since pembrolizumab was introduced in 2017, studies revealing current survival rates in aUC are lacking. This study aimed to assess (1) the improvement in survival among real-world patients with aUC after the introduction of pembrolizumab and (2) the direct survival-prolonging effect of pembrolizumab. METHODS: This multicenter retrospective study included 531 patients with aUC undergoing salvage chemotherapy, including 200 patients treated in the pre-pembrolizumab era (2003-2011; earlier era) and 331 patients treated in a recent 5-year period (2016-2020; recent era). Using propensity score matching (PSM), cancer-specific survival (CSS) and overall survival (OS) were compared between the earlier and recent eras, in addition to between the recent era, both with and without pembrolizumab use, and the earlier era. RESULTS: After PSM, the recent era cohort had significantly longer CSS (21 months) and OS (19 months) than the earlier era cohort (CSS and OS: 12 months). In secondary analyses using PSM, patients treated with pembrolizumab had significantly longer CSS (25 months) and OS (24 months) than those in the earlier era cohort (CSS and OS: 11 months), whereas patients who did not receive pembrolizumab in the recent era had similar outcomes (CSS and OS: 14 months) as the earlier era cohort (CSS and OS: 12 months). CONCLUSIONS: Patients with aUC treated in the recent era exhibited significantly longer survival than those treated before the introduction of pembrolizumab. The improved survival was primarily attributable to the use of pembrolizumab.

Preoperative CT volumetry of estimated residual kidney for prediction of postoperative chronic kidney disease in patients with renal cell carcinoma.

BACKGROUND: Surgical treatments for renal cell carcinoma reduces kidney volume to some degree and may derive postsurgical chronic kidney disease. We made a new marker for postoperative renal function using CT volumetry. To determine the impact of various parameters including this marker, we observed pre- and postsurgical renal function of experienced cases. METHODS: From 2004 to 2014, we underwent total or partial nephrectomy for 181 patients with renal carcinoma in a single institution. Of the total, 138 cases with presurgical CT volumetry were included in this study. We evaluated parameters for assessments of peri- and postoperative renal function including age, gender, serum creatinine, eGFR, performed surgery, pathology, estimated residual kidney volume and associated disease. Presence or absence of acute kidney injury (AKI) and chronic kidney disease (CKD) were also evaluated before, immediately after and 5 years after surgery. RESULTS: Multiple logistic regression analysis identified AKI, preoperative eGFR and estimated residual kidney volume as significant prognostic factors for the postoperative CKD. Moreover, cases with triple positive of these factors suffer postoperative CKD more significantly than those with one or two positives. CONCLUSION: Using these predictive factors, we may determine patients with high risk for CKD who require an early intervention of renal protective treatment.

Laparoscopic sacrocolpopexy for pelvic organ prolapse: Comparison of standard versus tacker combination method.

OBJECTIVE: To compare the surgical outcomes of laparoscopic sacrocolpopexy for pelvic organ prolapse between a group in which only sutures were used (standard method), and a group in which a combination of tackers and sutures were used (tacker combination method). METHODS: A total of 77 patients who underwent laparoscopic sacrocolpopexys from June 2016 to October 2019 were divided into a suture group (36 patients) and a suture + tacker group (41 patients). We retrospectively compared operation time, amount of blood loss, postoperative length of hospital stay, incidence of perioperative complications and anatomical cure rate 1 year after surgery. Lower urinary tract symptoms were evaluated using symptom questionnaires and objective parameters. RESULTS: Operation time in the suture + tacker group was shorter (104.9 ± 27.0 vs 147.5 ± 33.7 min; P < 0.0001). The incidence of perioperative complications in the suture group and the suture + tacker group was 2.8% and 2.4%, respectively (P = 0.9409). Anatomical cure rates at 1 year after surgery were 94.4% and 100%, respectively (P = 0.2153). Both groups showed significant improvement after 1 year for International Prostate Symptom Score total and quality of life score, Overactive Bladder Symptom Score total score, voided volume, maximum urinary flow rate and post-void residual. [Corrections added on 7 September 2021 after first online publication: the first two P-values have been updated.] CONCLUSIONS: The combined use of sutures and tackers in laparoscopic sacrocolpopexy simplifies the procedure and translates into shorter operation time. Surgical outcomes at 1 year and improvement of lower urinary tract symptoms are similar regardless of the technique.

Low reduction of prostate volume is a significant predictor of prostate cancer at subsequent biopsy in patients with dutasteride: A retrospective study.

Appropriate decision of prostate biopsy in men with 5α-reductase inhibitor (5AR inhibitor) is still unclear to avoid unnecessary biopsy. We retrospectively investigated patients with initial PSA 4.0 ng/ml or more and underwent subsequent prostate biopsy following dutasteride treatment. From September 2009 to August 2018, 399 cases of benign prostate hyperplasia (BPH) were treated with dutasteride in our department. Of the total, 36 cases with elevated pre-treatment PSA (4.0 ng/ml or more) and underwent subsequent prostate biopsy were included into this study. We evaluated PSA kinetics and changing prostate volumes (PV), and detection of prostate cancer. Overall, average PSA reduced by half at 6 months from dosing. Pre-treatment biopsy was performed in 17 of 36 cases, and all were diagnosed as having no malignancy. After treatment, prostate cancer was detected in 15 cases by subsequent biopsy. Fourteen of 15 cases were clinically significant cancer (Gleason score 7 or more). Logistic regression analysis detected a nominal association between prostate cancer detection and three variants, PSAD, PV reduction (1-Before/After PV) and abnormal MRI findings. In addition to abnormal MRI findings and pre-treatment of high PSAD, the case with low reduction of PV after treatment should consider performing prostate biopsy.

Identification of new octamer transcription factor 1-target genes upregulated in castration-resistant prostate cancer.

Octamer transcription factor 1 (OCT1) is an androgen receptor (AR)-interacting partner and regulates the expression of target genes in prostate cancer cells. However, the function of OCT1 in castration-resistant prostate cancer (CRPC) is not fully understood. In the present study, we used 22Rv1 cells as AR-positive CRPC model cells to analyze the role of OCT1 in CRPC. We showed that OCT1 knockdown suppressed cell proliferation and migration of 22Rv1 cells. Using microarray analysis, we identified four AR and OCT1-target genes, disks large-associated protein 5 (DLGAP5), kinesin family member 15 (KIF15), non-SMC condensin I complex subunit G (NCAPG), and NDC80 kinetochore complex component (NUF2) in 22Rv1 cells. We observed that knockdown of DLGAP5 and NUF2 suppresses growth and migration of 22Rv1 cells. Furthermore, immunohistochemical analysis showed that positive expression of DLGAP5 in prostate cancer specimens is related to poor cancer-specific survival rates of patients. Notably, enhanced expression of DLGAP5 was observed in CRPC tissues of patients. Thus, our findings suggest that these four genes regulated by the AR/OCT1 complex could have an important role in CRPC progression.

Establishing a cryopreservation protocol for patient-derived xenografts of prostate cancer.

BACKGROUND: Serially transplantable patient-derived xenografts (PDXs) are invaluable preclinical models for studying tumor biology and evaluating therapeutic agents. As these models are challenging to establish from prostate cancer specimens, the ability to preserve them through cryopreservation has several advantages for ongoing research. Despite this, there is still uncertainty about the ability to cryopreserve PDXs of prostate cancer. This study compared three different cryopreservation protocols to identify a method that can be used to reproducibly cryopreserve a diverse cohort of prostate cancer PDX models. METHODS: One serially transplantable prostate cancer PDX from the Melbourne Urological Research Alliance cohort was used to compare three cryopreservation protocols: slow freezing in fetal calf serum (FCS) with 10% dimethyl sulfoxide (DMSO), FCS with 10% DMSO supplemented with the Rho-associated kinase (ROCK) inhibitor Y-27632 and vitrification. The efficiency of the slow freezing protocols was then assessed in 17 additional prostate cancer PDXs. Following cryopreservation, PDXs were re-established in host mice that were either intact and supplemented with testosterone or castrated. Graft take rate, tumor growth, histological features, and transcriptome profiles before and after cryopreservation were compared. RESULTS: Slow freezing maintained the viability and histological features of prostate cancer PDXs, and the addition of a ROCK inhibitor increased their growth following cryopreservation. Using the slow freezing method, we re-established 100% of PDXs grown in either testosterone-supplemented or castrated host mice. Importantly, the long-term tumor growth rate and transcriptome profile were maintained following cryopreservation. CONCLUSION: This study has identified a protocol to reliably cryopreserve and re-establish a diverse cohort of serially transplantable PDXs of prostate cancer. This study has the potential to significantly improve the practicality of maintaining PDX models. Cryopreservation may also increase the accessibility of these important resources and provide new opportunities for preclinical studies on a broader spectrum of prostate tumors.

Tension-free vaginal mesh surgery versus laparoscopic sacrocolpopexy for pelvic organ prolapse: Analysis of perioperative outcomes using a Japanese national inpatient database.

OBJECTIVE: To compare nationwide outcomes of tension-free vaginal mesh surgery and laparoscopic sacrocolpopexy for the treatment of pelvic organ prolapse in Japan. METHODS: Using the Diagnosis Procedure Combination database, we collected data on female patients who underwent tension-free vaginal mesh surgery or laparoscopic sacrocolpopexy for pelvic organ prolapse from April 2014 to March 2015. We compared the proportion of perioperative adverse events, duration of anesthesia, total costs and postoperative length of stay between the groups. Univariate and multivariate analyses were carried out for age, comorbidity, mesh volume, additional concomitant surgery and hospital volume. RESULTS: We identified 3023 patients, including 2388 who underwent tension-free vaginal mesh surgery, and 635 who underwent laparoscopic sacrocolpopexy. The median age at the time of surgery was significantly higher in the tension-free vaginal mesh group (71 vs 66 years; P < 0.001). The tension-free vaginal mesh group had a higher proportion of all adverse events (7.1% vs 1.8%; P < 0.001) and a higher proportion of genitourinary complications (5.7% vs 1.1%; P < 0.001). The median duration of anesthesia was shorter in the tension-free vaginal mesh group (150 vs 286 min; P < 0.001). The total cost was significantly lower in the tension-free vaginal mesh group. CONCLUSIONS: Both procedures offer favorable results for surgical treatment of pelvic organ prolapse. Overall, the tension-free vaginal mesh procedure seems to represent a good option for high-risk women, such as elderly patients, whereas laparoscopic sacrocolpopexy is useful for younger patients with a higher level of sexual activity.

CLDN8, an androgen-regulated gene, promotes prostate cancer cell proliferation and migration.

The proliferation of prostate cancer cells is controlled by the androgen receptor (AR) signaling pathway. However, the function of AR target genes has not been fully elucidated. In previous studies, we have identified global AR binding sites and AR target genes in prostate cancer cells. Here, we focused on Claudin 8 (CLDN8), a protein constituting tight junctions in cell membranes. We found one AR binding site in the promoter region and two functional androgen-responsive elements in the sequence. Reporter assay revealed that transcriptional activation of the CLDN8 promoter by androgen is dependent on these androgen-responsive elements. Furthermore, CLDN8 mRNA is induced by androgen time-dependently and the induction is blocked by AR inhibitor, suggesting that AR is involved in the transcriptional activation. In addition, our functional analyses by overexpression and knockdown of CLDN8 mRNA indicate that CLDN8 promotes prostate cancer cell proliferation and migration. Claudin 8 was overexpressed in prostate cancer clinical samples compared to benign tissues. Furthermore, we found that CLDN8 regulates intracellular signal transduction and stabilizes the cytoskeleton. Taken together, these results indicate that CLDN8 functions as an AR downstream signal to facilitate the progression of prostate cancer. Claudin 8 may be a novel molecular target for prostate cancer therapy.

ACSL3 promotes intratumoral steroidogenesis in prostate cancer cells.

Long-chain acyl-coenzyme A (CoA) synthetase 3 (ACSL3) is an androgen-responsive gene involved in the generation of fatty acyl-CoA esters. ACSL3 is expressed in both androgen-sensitive and castration-resistant prostate cancer (CRPC). However, its role in prostate cancer remains elusive. We overexpressed ACSL3 in androgen-dependent LNCaP cells and examined the downstream effectors of ACSL3. Furthermore, we examined the role of ACSL3 in the androgen metabolism of prostate cancer. ACSL3 overexpression led to upregulation of several genes such as aldo-keto reductase 1C3 (AKR1C3) involved in steroidogenesis, which utilizes adrenal androgen dehydroepiandrosterone sulfate (DHEAS) as substrate, and downregulated androgen-inactivating enzyme UDP-glucuronosyltransferase 2 (UGT2B). Exposure to DHEAS significantly increased testosterone levels and cell proliferative response in ACSL3-overexpressing cells when compared to that in control cells. A public database showed that ACSL3 level was higher in CRPC than in hormone-sensitive prostate cancer. CRPC cells showed an increased expression of ACSL3 and an expression pattern of AKR1C3 and UGT2B similar to ACSL3-overexpressing cells. DHEAS stimulation significantly promoted the proliferation of CRPC cells when compared to that of LNCaP cells. These findings suggest that ACSL3 contributes to the growth of CRPC through intratumoral steroidogenesis (i.e. promoting androgen synthesis from DHEAS and preventing the catabolism of active androgens).

A novel prognostic factor TRIM44 promotes cell proliferation and migration, and inhibits apoptosis in testicular germ cell tumor.

Tripartite motif 44 (TRIM44) is one of the TRIM family proteins that are involved in ubiquitination and degradation of target proteins by modulating E3 ubiquitin ligases. TRIM44 overexpression has been observed in various cancers. However, its association with testicular germ cell tumor (TGCT) is unknown. We aimed to investigate the clinical significance of TRIM44 and its function in TGCT. High expression of TRIM44 was significantly associated with α feto-protein levels, clinical stage, nonseminomatous germ cell tumor (NSGCT), and cancer-specific survival (P = 0.0009, P = 0.0035, P = 0.0004, and P = 0.0140, respectively). Multivariate analysis showed that positive TRIM44 IR was an independent predictor of cancer-specific mortality (P = 0.046). Gain-of-function study revealed that overexpression of TRIM44 promoted cell proliferation and migration of NTERA2 and NEC8 cells. Knockdown of TRIM44 using siRNA promoted apoptosis and repressed cell proliferation and migration in these cells. Microarray analysis of NTERA2 cells revealed that tumor suppressor genes such as CADM1, CDK19, and PRKACB were upregulated in TRIM44-knockdown cells compared to control cells. In contrast, oncogenic genes including C3AR1, ST3GAL5, and NT5E were downregulated in those cells. These results suggest that high expression of TRIM44 is associated with poor prognosis and that TRIM44 plays significant role in cell proliferation, migration, and anti-apoptosis in TGCT.

Identification of frequent differentially methylated region in sporadic bladder cancers.

INTRODUCTION: Aberrant methylation levels in the cytosine-phosphate-guanine island (CpGi) region from exon 1 to intron 1 of the zygote arrest 1 (ZAR1) gene have been reported in several types of human cancers, including melanoma, brain tumor, and hepatocellular carcinoma. In the present study, methylation levels at the CpGi of ZAR1 exon 1/intron 1 in bladder cancer specimens were analyzed using mass spectrometry. MATERIALS AND METHODS: Genomic DNA was extracted from 20 sporadic bladder cancers, and the methylation levels at ZAR1 CpGi were quantitatively examined by the MassARRAY EpiTYPER method. RESULT: The methylation levels at specific CpG sites of the ZAR1 CpGi were significantly lower in high-grade bladder cancers than in low-grade tumors. CONCLUSIONS: The results of the present study indicated a decreased methylation level at CpG sites of ZAR1 exon 1/intron 1. CpGi could serve as a biomarker for invasive bladder cancer.

Pyrrole-imidazole polyamide targeted to break fusion sites in TMPRSS2 and ERG gene fusion represses prostate tumor growth.

Aberrant overexpression of ERG induced by the TMPRSS2-ERG gene fusion is likely involved in the development of prostate cancer. Synthetic pyrrole-imidazole (PI) polyamides recognize and attach to the minor groove of DNA with high affinity and specificity. In the present study, we designed a PI polyamide targeting TMPRSS2-ERG translocation breakpoints and assessed its effect on human prostate cancer cells. Our study identified that this PI polyamide repressed the cell and tumor growth of androgen-sensitive LNCaP prostate cancer cells. Targeting of these breakpoint sequences by PI polyamides could be a novel approach for the treatment of prostate cancer.