Genome-Wide CRISPR Screen Identifies an NF2-Adherens Junction Mechanistic Dependency for Cardiac Lineage.

BACKGROUND: Cardiomyocyte differentiation involves a stepwise clearance of repressors and fate-restricting regulators through the modulation of BMP (bone morphogenic protein)/Wnt-signaling pathways. However, the mechanisms and how regulatory roadblocks are removed with specific developmental signaling pathways remain unclear. METHODS: We conducted a genome-wide CRISPR screen to uncover essential regulators of cardiomyocyte specification in human embryonic stem cells using a myosin heavy chain 6 (MYH6)-GFP (green fluorescence protein) reporter system. After an independent secondary single guide ribonucleic acid validation of 25 candidates, we identified NF2 (neurofibromin 2), a moesin-ezrin-radixin like (MERLIN) tumor suppressor, as an upstream driver of early cardiomyocyte lineage specification. Independent monoclonal NF2 knockouts were generated using CRISPR-Cas9, and cell states were inferred through bulk RNA sequencing and protein expression analysis across differentiation time points. Terminal lineage differentiation was assessed by using an in vitro 2-dimensional-micropatterned gastruloid model, trilineage differentiation, and cardiomyocyte differentiation. Protein interaction and post-translation modification of NF2 with its interacting partners were assessed using site-directed mutagenesis, coimmunoprecipitation, and proximity ligation assays. RESULTS: Transcriptional regulation and trajectory inference from NF2-null cells reveal the loss of cardiomyocyte identity and the acquisition of nonmesodermal identity. Sustained elevation of early mesoderm lineage repressor SOX2 and upregulation of late anticardiac regulators CDX2 and MSX1 in NF2 knockout cells reflect a necessary role for NF2 in removing regulatory roadblocks. Furthermore, we found that NF2 and AMOT (angiomotin) cooperatively bind to YAP (yes-associated protein) during mesendoderm formation, thereby preventing YAP activation, independent of canonical MST (mammalian sterile 20-like serine-threonine protein kinase)-LATS (large tumor suppressor serine-threonine protein kinase) signaling. Mechanistically, cardiomyocyte lineage identity was rescued by wild-type and NF2 serine-518 phosphomutants, but not NF2 FERM (ezrin-radixin-meosin homology protein) domain blue-box mutants, demonstrating that the critical FERM domain-dependent formation of the AMOT-NF2-YAP scaffold complex at the adherens junction is required for early cardiomyocyte lineage differentiation. CONCLUSIONS: These results provide mechanistic insight into the essential role of NF2 during early epithelial-mesenchymal transition by sequestering the repressive effect of YAP and relieving regulatory roadblocks en route to cardiomyocytes.

Prognostic Impact of Histologic Subtype and Divergent Differentiation in Patients with Metastatic Urothelial Carcinoma Treated with Enfortumab Vedotin: A Multicenter Retrospective Study.

Subtype of urothelial carcinoma (SUC), defined here as urothelial carcinoma with any histologic subtype or divergent differentiation, is a clinically aggressive disease. However, the efficacy of enfortumab vedotin (EV) against SUC remains unclear. Hence, this study aimed to assess the oncological outcomes of patients with SUC treated with EV for metastatic disease. We retrospectively evaluated consecutive patients with advanced lower and upper urinary tract cancer who received EV after platinum-based chemotherapy and immune checkpoint blockade therapy at six institutions. The objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were compared between patients with pure urothelial carcinoma (PUC) and those with SUC. We identified 44 and 18 patients with PUC and SUC, respectively. Squamous differentiation was the most common subtype element, followed by glandular differentiation and sarcomatoid subtype. Although patients with SUC had a comparable ORR to those with PUC, the duration of response for SUC was short. Patients with SUC had poorer PFS than those with PUC; however, no significant difference was observed in OS. Multivariate analysis revealed that SUC was significantly associated with shorter PFS. Although the response of metastatic SUC to EV was similar to that of PUC, SUC showed faster progression than PUC.

Early Phase Persistent Changes in the White Blood Cell Fraction in Patients With Advanced Urothelial Carcinoma Treated With Pembrolizumab: A Multicenter Retrospective Study.

BACKGROUND/AIM: The association of clinical outcomes with posttreatment persistent changes in eosinophils and other white blood cell (WBC) subtypes in patients with advanced urothelial cancer (UC) treated with pembrolizumab after the failure of platinum-based chemotherapy is unclear. PATIENTS AND METHODS: We retrospectively analyzed 87 patients with advanced UC who received pembrolizumab after the failure of platinum-based chemotherapy. The changes in WBC subtypes from pretreatment were evaluated three and six weeks after pembrolizumab administration. The association between the changes in the WBC subtypes and clinical outcomes was then evaluated using the Kaplan-Meier method and a Cox regression model. RESULTS: Among WBC subtypes, significant changes in the absolute (AEC) and relative eosinophil count (REC) and the neutrophil-to-eosinophil ratio (NER) were observed at three and six weeks compared with pretreatment (p<0.001). Multivariable Cox regression analyses revealed that a persistent decrease in AEC and REC and a persistent increase in NER were associated with poor overall survival. CONCLUSION: Persistent increase in AEC and REC and decrease in NER in the early phase after pembrolizumab may be significant early predictive markers of improved clinical outcomes in patients with advanced UC receiving pembrolizumab.

The Eosinophil Changes, Efficacy and Safety of Pembrolizumab in Advanced Urothelial Carcinoma Patients with an Older Age and a Poor Performance Status.

Background: To evaluate the eosinophil changes, efficacy and safety of pembrolizumab treatment in advanced urothelial carcinoma patients of older age and those with a poor performance status (PS). Materials and Methods: Consecutive patients with advanced UC who received pembrolizumab after the failure of platinum-based chemotherapy between January 2018 and June 2021 were retrospectively examined. Results: 105 patients (median age, 72 years), 71.4% of whom were men, were enrolled. Patients of ≥75 years of age were considered to be older patients (n=40), and patients with PS ≥2 were considered to have a poor PS (n=10). The objective response and disease control rates were 42.5% and 52.5%, respectively, in older patients and 0% and 10.0%, respectively, in patients with a poor PS. Overall survival (OS) in the older and younger groups did not differ to a statistically significant extent. However, a poor PS was significantly associated with poor survival. Safety analyses demonstrated no significant difference in the occurrence of any immune-related adverse events (irAEs), including grade ≥3, between the older and younger groups. However, a poor PS was significantly associated with the low occurrence of any irAEs. The change of the eosinophil count, the increase of the relative eosinophil count (REC) and the decrease of the neutrophil-to-eosinophil ratio (NER) did not differ to a statistically significant extent between the older and younger groups, but showed significant differences between the poor and good PS (PS 0-1) groups. Conclusion: Pembrolizumab for advanced UC demonstrated similar changes in the eosinophil count, efficacy and toxicity in both older and younger patients. In patients with a poor PS, although toxicity was significantly lower, survival was significantly worse, and neither an increase in REC nor a decrease in NER were observed, but these values showed significant changes in patients with a good PS.

A prospective, single-center, randomized clinical trial to evaluate the efficacy of three types of laser vaporization surgeries using a 180-W GreenLight XPS laser, a 300-W diode laser, and a 200-W thulium laser for the treatment of benign prostatic hyperplasia.

OBJECTIVES: This study aimed to compare the safety and efficacy of three different laser prostate vaporization surgeries, which were photoselective vaporization of the prostate (PVP), diode laser vaporization (DVP), and thulium laser vaporization (ThuVAP), for the treatment of benign prostatic hyperplasia (BPH) in a randomized clinical trial. METHODS: A total of 71 consecutive patients with BPH were included; 23 patients were treated with PVP, 23 with DVP, and 25 with ThuVAP. Patients were evaluated with disease-related symptomatic questionnaires, Quality of Life (QOL) Index, and maximum urinary flow rate (Qmax ) for 12 months. Patients were monitored to record operation/vaporization time, 24-hour hemoglobin/sodium drop, length of catheterization/hospitalization, and perioperative/postoperative complications. RESULTS: In all three groups, patients showed significant and comparable improvements in symptom scores, QOL Index, and Qmax during the 12-month follow-up period. The mean operation/vaporization time was equivalent across all three groups at 69/23 (PVP), 81/34 (DVP), and 76/32 minutes (ThuVAP), while the applied laser energy was lower for PVP at 157 kJ compared to the other two techniques (DVP at 358 kJ, ThuVAP at 240 kJ). The mean vaporization rates per unit energy were significantly different between the three groups (PVP 0.16, DVP 0.09, and ThuVAP 0.09 mL/kJ). There were no significant differences in the main safety profiles between the three groups. CONCLUSIONS: Our study demonstrated that these three types of laser surgeries are similar in terms of complications and outcomes, with excellent hemostasis and high patient satisfaction. It was suggested that sufficient tissue vaporization could be achieved using less energy through PVP surgery.

Association Between Immune-Related Adverse Events and Efficacy and Changes in the Relative Eosinophil Count Among Patients with Advanced Urothelial Carcinoma Treated by Pembrolizumab.

Background: To evaluate the association between immune-related adverse events (irAEs) and the clinical outcomes and also between irAEs and the post-treatment changes in the relative eosinophil count (REC) in advanced urothelial carcinoma (UC) patients treated with pembrolizumab. Materials and Methods: This retrospective study analyzed 105 advanced UC patients treated with pembrolizumab after disease progression on platinum-based chemotherapy between January 2018 and June 2021. The association between the occurrence of irAEs and the efficacy of pembrolizumab was investigated. The change in the REC from before the initiation of pembrolizumab therapy, to three weeks after treatment and the incidence of irAEs were determined. Results: Overall irAEs were associated with a significantly higher objective response rate (ORR) (58.8% vs 25.4%, P<0.001), a longer progression-free survival (PFS) (25.1 months vs 3.1 months, P< 0.001) and overall survival (OS) (31.2 months vs 11.5 months, P< 0.001) compared to patients without irAEs; however, grade ≥3 irAEs were not associated with the ORR (36.4% vs 36.2%, P=0.989), PFS (9.5 vs 5.5 months, P=0.249), or OS (not reached vs 13.7 months, P=0.335). Compared to a decreased REC at 3 weeks after pembrolizumab, an increased relative REC at 3 weeks was not associated with the incidence of any-grade irAEs (32.3% vs 32.5%, P=0.984) or of grade ≥3 irAEs (10.8% vs 10.0%, P=0.900). Multivariate analyses revealed a female sex (P=0.005), Eastern Cooperative Oncology Group Performance Status ≥1 (P=0.024), albumin <3.7 g/dl (P<0.001), decreased REC (3 weeks later) (P<0.001), and the absence of irAEs of any grade (P=0.002) to be independently associated with a worse OS. Conclusion: Patients with irAEs showed a significantly better survival compared to patients without irAEs in advanced UC treated with pembrolizumab. An increased posttreatment REC may be a marker predicting improved clinical outcomes and it had no significant relationship with the incidence of irAEs.

Efficacy of Pembrolizumab in Patients With Variant Urothelial Carcinoma: A Multicenter Retrospective Study.

INTRODUCTION: Although variant urothelial carcinoma (VUC, defined here as urothelial carcinoma with any histological variant) is a clinically aggressive disease, the efficacy of pembrolizumab against VUC is not well characterized. This study assessed the therapeutic response and survival outcomes in patients with advanced VUC treated with pembrolizumab for unresectable recurrent or metastatic disease. PATIENTS AND METHODS: We retrospectively evaluated 103 patients with advanced bladder and upper urinary tract cancer who received pembrolizumab after failure of platinum-based chemotherapy at 6 institutions between January 2018 and June 2021. Objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) were compared between patients with pure urothelial carcinoma (PUC) and those with VUC. RESULTS: We identified 81 and 22 patients with PUC and VUC, respectively. Squamous differentiation (n = 14) was the most common variant element, followed by glandular differentiation (n = 3) and micropapillary variant (n = 3). Baseline characteristics were comparable between the groups. Patients with VUC showed significantly better ORR (59.1% vs. 29.6%, P = .014) and comparable DCR (68.2% vs. 49.4%, P = .150) compared to those with PUC. There were no significant differences between the PUC and VUC groups with respect to PFS (median 5.0 months vs. 10.4 months, P = .222) or OS (median 13.5 months vs. 23.8 months, P = .497). CONCLUSION: Response of VUC to pembrolizumab was not inferior to that of PUC in patients with advanced-stage bladder and upper urinary tract cancer.

The Association of Clinical Outcomes with Posttreatment Changes in the Relative Eosinophil Counts and Neutrophil-to-Eosinophil Ratio in Patients with Advanced Urothelial Carcinoma Treated with Pembrolizumab.

BACKGROUND: To evaluate the association of clinical outcomes with posttreatment changes in the relative eosinophil count (REC) and neutrophil-to-eosinophil ratio (NER) in patients with advanced urothelial cancer (UC) treated with pembrolizumab. MATERIALS AND METHODS: We retrospectively analyzed 105 patients with advanced UC who received pembrolizumab after the failure of platinum-based chemotherapy. The REC and NER before and three weeks after pembrolizumab were recorded. A receiver operating characteristic curve was used to determine the optimal cut-off values for analyzing the risk. RESULTS: There were no significant differences in the overall survival (OS) between the REC ≥4.8% and <4.8% groups and the NER ≥13.7 and <13.7 groups before pembrolizumab (p=0.997 and 0.669, respectively). However, a significant difference in the OS was confirmed between the increased and decreased REC groups and between the decreased and increased NER groups at 3 weeks after pembrolizumab (p<0.001 and 0.002, respectively). Multivariate analyses revealed that an Eastern Cooperative Oncology Group Performance Status ≥2 (P=0.003), albumin <3.7 g/dl (p=0.002), LDH >246 U/L (p=0.011), disease site ≥3 organs (p=0.019), decreased posttreatment REC (3 weeks later) (p=0.002) and increased posttreatment NER (3 weeks later) (p=0.022) were independent prognostic factors for a worse OS. CONCLUSION: An increased REC and decreased NER after pembrolizumab may be significant early predictive markers of improved clinical outcomes in patients with advanced UC receiving pembrolizumab.

Clinical Outcomes of Mixed Response to Pembrolizumab in Advanced Urothelial Carcinoma After Platinum-based Chemotherapy.

BACKGROUND/AIM: Despite the presence of a mixed response (MR) in patients with urothelial carcinoma (UC) who receive immune checkpoint inhibitors, the clinical outcome of these patient has not been reported. We evaluated the clinical outcome of MR to pembrolizumab for advanced UC. PATIENTS AND METHODS: Advanced UC patients who received pembrolizumab after platinum-based chemotherapy failure with measurable disease in multiple organs were retrospectively analyzed. RESULTS: Among 31 patients, MR [including progressive disease (PD)+complete response (CR) or partial response (PR)] was confirmed in 4 (12.9%). The median overall survival (OS) of the CR+PR (including CR+SD±PR), stable disease (SD), PD (including PD±SD) and MR groups was 16.0, 5.1, 5.4 and 4.3 months, respectively. There was no significant difference in the OS between the MR and CR+PR response groups (log-rank test, p=0.069). CONCLUSION: A mixed response to pembrolizumab in advanced UC was not uncommon. Despite the non-significant difference in the OS between the mixed and CR+PR response groups, the OS of the MR group tended to be similar to that of the SD and PD response groups.

Organ-Specific Tumor Response to Pembrolizumab in Advanced Urothelial Carcinoma After Platinum-Based Chemotherapy.

BACKGROUND: To evaluate the organ-specific therapeutic effect of pembrolizumab after the failure of platinum-based chemotherapy for advanced urothelial carcinoma (UC). MATERIALS AND METHODS: Patients with advanced UC who received pembrolizumab after the failure of platinum-based chemotherapy and who had measurable disease were retrospectively analyzed. The objective response rate (ORR) and organ-specific response rate (OSRR) were evaluated according to Response Evaluation Criteria in Solid Tumors, version 1.1. RESULTS: We analyzed 69 patients (male, n=51; median age, 71 years) with 226 metastases. The ORR was 23.2%. In total, 32, 31, 16, 14, 13 and 7 patients had measurable lung (OSSR 31.3%), lymph node (OSSR 29.0%), local recurrence (OSSR 12.5%), primary tumor organ (OSSR 7.1%), liver (OSSR 23.1%) and bone (OSSR 28.6%) disease, respectively. The median overall survival (OS) for pembrolizumab was 10.9 months (95% confidence interval, 5.9­13.7 months). Regarding organ-specific OS, a Log rank test significant differences in OS were confirmed between patients with and without primary tumor organ disease (p=0.046) and liver metastasis (p<0.001). CONCLUSION: Metastases and primary tumor organ disease showed different tumor responses to pembrolizumab. The most prominent tumor response was found in lung metastasis and the least response was found in primary organ sites. The mechanisms of these different responses were unclear and there does not appear to be a constant trend between tumor shrinkage and OS in tumor sites. Further studies are needed.

Transformation of hard pollen into soft matter.

Pollen's practically-indestructible shell structure has long inspired the biomimetic design of organic materials. However, there is limited understanding of how the mechanical, chemical, and adhesion properties of pollen are biologically controlled and whether strategies can be devised to manipulate pollen beyond natural performance limits. Here, we report a facile approach to transform pollen grains into soft microgel by remodeling pollen shells. Marked alterations to the pollen substructures led to environmental stimuli responsiveness, which reveal how the interplay of substructure-specific material properties dictates microgel swelling behavior. Our investigation of pollen grains from across the plant kingdom further showed that microgel formation occurs with tested pollen species from eudicot plants. Collectively, our experimental and computational results offer fundamental insights into how tuning pollen structure can cause dramatic alterations to material properties, and inspire future investigation into understanding how the material science of pollen might influence plant reproductive success.

The Expression of Ubiquitous Mitochondrial Creatine Kinase Is Downregulated as Prostate Cancer Progression.

BACKGROUND: Mitochondria play crucial roles in cell signaling events, interorganellar communication, aging, cell proliferation and apoptosis, and mitochondrial impairment has been shown to accelerate or modulate cancer progression. Ubiquitous mitochondrial creatine kinase (uMtCK) is predominantly localized in the intermembrane space of mitochondria and catalyzes the reversible exchange of high-energy phosphate between adenosine tri-phosphate (ATP) and phosphocreatine. However, little is known about its expression and function in human prostate cancer progression. METHOD: We investigated the expression of uMtCK in 148 prostate carcinoma tissues and matched normal tissue by immunohistochemistry. The expression and localization of uMtCK and hexokinase II, a marker of glycolysis, were examined in prostate carcinoma cell lines using western blot and immunofluorescence. RESULTS: MtCK expression was significantly lower in high Gleason grade carcinoma compared with normal prostate or low grade carcinoma. Western blot further revealed that uMtCK was highly expressed in LNCaP and 22Rv1 cell lines, as well as in the normal prostate cell line RWPE-1. However, uMtCK expression was almost absent in PC3 and DU145 cell lines, in correlation with absent or mutant p53 expression, respectively. In contrast, hexokinase II was overexpressed in PC3 cells. Moreover, in the low uMtCK expressing cell lines, glycolytic ATP production was increased, whereas mitochondrial ATP production was decreased. CONCLUSIONS: These data suggest that uMtCK is downregulated as prostate cancer progresses in correlation with a metabolic switch in ATP usage.

Inhibition of protein kinase C/Twist1 signaling augments anticancer effects of androgen deprivation and enzalutamide in prostate cancer.

PURPOSE: The progression of prostate cancer to metastatic and castration-resistant disease represents a critical step. We previously showed that the transcription factor Twist1, which promotes epithelial-mesenchymal transition, was involved in castration-resistant progression. Similarly, protein kinase C (PKC) has been implicated in both metastatic progression and castration resistance in prostate cancer. EXPERIMENTAL DESIGN: In this study, we aimed to elucidate the role of PKC/Twist1 signaling in castration resistance, and to apply this information to the development of a novel therapeutic concept using PKC inhibitor Ro31-8220 against prostate cancer using various prostate cancer cell lines. RESULTS: Androgen deprivation and the next-generation antiandrogen enzalutamide induced PKC activation and Twist1 expression, which were reversed by the PKC inhibitor Ro31-8220. Ro31-8220 suppressed cell proliferation in androgen-dependent prostate cancer LNCaP cells, which was augmented by its combination with androgen deprivation or enzalutamide. The favorable anticancer effects of the combination of Ro31-8220 and enzalutamide were also observed in castration-resistant C4-2 and 22Rv1 cells. Furthermore, PKC phosphorylation was elevated in castration-resistant and enzalutamide-resistant cells compared with their parental cells, leading to persistent sensitivity to Ro-31-8220 in castration- and enzalutamide-resistant cells. CONCLUSIONS: Taken together, these findings indicate that PKC/Twist1 signaling contributes to castration resistance as well as enzalutamide resistance in prostate cancer, and suggest that therapeutics targeting PKC/Twist1 signaling, such as PKC inhibitors, represent a promising novel therapeutic strategy for prostate cancer, especially castration-resistant prostate cancer, when combined with enzalutamide.

Mutual regulation between Raf/MEK/ERK signaling and Y-box-binding protein-1 promotes prostate cancer progression.

PURPOSE: Y-box-binding protein-1 (YB-1) is known to conduct various functions related to cell proliferation, anti-apoptosis, epithelial-mesenchymal transition, and castration resistance in prostate cancer. However, it is still unknown how YB-1 affects cancer biology, especially its correlations with the mitogen-activated protein kinase (MAPK) signaling pathway. Therefore, we aimed to examine the interaction between YB-1 and the MAPK pathway in prostate cancer. EXPERIMENTAL DESIGN: Quantitative real-time PCR, Western blotting, and co-immunoprecipitation assay were conducted in prostate cancer cells. YB-1, phosphorylated YB-1 (p-YB-1), and ERK2 protein expressions in 165 clinical specimens of prostate cancer were investigated by immunohistochemistry. YB-1, p-YB-1, and ERK2 nuclear expressions were compared with clinicopathologic characteristics and patient prognoses. RESULTS: EGF upregulated p-YB-1, whereas MEK inhibitor (U0126, PD98059) decreased p-YB-1. Inversely, silencing of YB-1 using siRNA decreased the expression of ERK2 and phosphorylated MEK, ERK1/2, and RSK. Furthermore, YB-1 interacted with ERK2 and Raf-1 and regulated their expressions, through the proteasomal pathway. Immunohistochemical staining showed a significant correlation among the nuclear expressions of YB-1, p-YB-1, and ERK2. The Cox proportional hazards model revealed that high ERK2 expression was an independent prognostic factor [HR, 7.947; 95% confidence interval (CI), 3.527-20.508; P<0.0001]. CONCLUSION: We revealed the functional relationship between YB-1 and MAPK signaling and its biochemical relevance to the progression of prostate cancer. In addition, ERK2 expression was an independent prognostic factor. These findings suggest that both the ERK pathway and YB-1 may be promising molecular targets for prostate cancer diagnosis and therapeutics.

Interaction between docetaxel resistance and castration resistance in prostate cancer: implications of Twist1, YB-1, and androgen receptor.

BACKGROUND: Taxanes, including docetaxel, are currently the only cytotoxic chemotherapeutic agents proven to confer survival benefit in patients with castration-resistant prostate cancer (CRPC). However, the merits of taxanes remain modest, and efforts are needed to improve their therapeutic efficacy. METHODS: We evaluated the sensitivity of prostate cancer cells to various agents using cytotoxicity assays. Gene and protein expression levels were evaluated by quantitative real-time polymerase chain reaction and Western blotting analysis, respectively. RESULTS: Hydrogen peroxide-resistant and castration-resistant cells that overexpressed Twist1 and Y-box binding protein-1 (YB-1) were cross-resistant to cytotoxic agents, including docetaxel. Twist1 regulated YB-1 expression in prostate cancer cells, supported by the induction of Twist1 and YB-1 by transforming-growth factor-ß, which is critical for taxane resistance. Twist1 and/or YB-1 were activated in docetaxel-resistant prostate cancer cells, and YB-1 was activated by docetaxel treatment. Conversely, Twist1 and YB-1 knockdown sensitized prostate cancer cells to cytotoxic agents, including docetaxel. In addition, androgen receptor (AR) knockdown increased cellular sensitivity to docetaxel, though AR expression in docetaxel-resistant LNCaP cells was paradoxically lower than in parental cells. Intriguingly, androgen deprivation treatment was more effective in docetaxel-resistant LNCaP cells compared with parental cells. CONCLUSIONS: Twist1/YB-1 and AR signaling promote docetaxel resistance in CRPC cells. However, docetaxel-resistant cells were collaterally sensitive to androgen deprivation because of down-regulation of AR expression, suggesting that the therapeutic effect of initial taxane treatment in hormone-naïve prostate cancer may be superior to that of salvage taxane treatment in CRPC.

Human heterochromatin protein 1 isoforms regulate androgen receptor signaling in prostate cancer.

Androgen receptor (AR) signaling is critical for the tumorigenesis and development of prostate cancer, as well as the progression to castration-resistant prostate cancer. We previously showed that the heterochromatin protein 1 (HP1) ß isoform plays a critical role in transactivation of AR signaling as an AR coactivator that promotes prostate cancer cell proliferation. However, the roles of other HP1 isoforms, HP1α and HP1γ, in AR expression and prostate cancer remain unclear. Here, we found that knockdown of HP1γ, but not HP1α, reduced AR expression and cell proliferation by inducing cell cycle arrest at G1 phase in LNCaP cells. Conversely, overexpression of full-length HP1α and its C-terminal deletion mutant increased AR expression and cell growth, whereas overexpression of HP1γ had no effect. Similarly, HP1α overexpression promoted 22Rv1 cell growth, whereas HP1γ knockdown reduced the proliferation of CxR cells, a castration-resistant LNCaP derivative. Taken together, HP1 isoforms distinctly augment AR signaling and cell growth in prostate cancer. Therefore, silencing of HP1ß and HP1γ may be a promising therapeutic strategy for treatment of prostate cancer.

Antioxidant therapy alleviates oxidative stress by androgen deprivation and prevents conversion from androgen dependent to castration resistant prostate cancer.

PURPOSE: Prostate cancer progression from androgen dependence to castration resistance results at least in part from oxidative stress induced by androgen deprivation therapy. We elucidated the state and the role of oxidative stress induced by androgen deprivation therapy and the possibility of antioxidant therapy in human prostate cancer. MATERIALS AND METHODS: We investigated 4-HNE (4-hydroxy-2-nonenal histidine adduct) staining, and Twist1, YB-1 and androgen receptor expression by immunohistochemistry in prostate cancer samples treated with or without neoadjuvant androgen deprivation therapy. Intracellular reactive oxygen species and protein expression were examined by CM-H(2)DCFDA and Western blot analysis, respectively. A cell proliferation assay and a mouse xenograft model were used to assess tumor growth. RESULTS: Androgen deprivation therapy increased oxidative stress, as shown by 4-HNE staining in human prostate cancer tissue. Twist1 and YB-1 expression was up-regulated by androgen deprivation, resulting in androgen receptor over expression. In LNCaP and 22Rv1 cells androgen deprivation increased intracellular reactive oxygen species and evoked Twist1, YB-1 and androgen receptor over expression, resulting in cell growth in a castration resistant manner. Growth was alleviated by N-acetyl-cysteine, an electrophile that supports glutathione production. N-acetyl-cysteine also decreased LNCaP and 22Rv1 tumor growth in castrated and noncastrated mice. CONCLUSIONS: Androgen deprivation therapy induced oxidative stress in in vitro and human prostate cancer. Antioxidant therapy using N-acetyl-cysteine appears to be a promising therapeutic modality for prostate cancer.

Y-box binding protein-1 promotes castration-resistant prostate cancer growth via androgen receptor expression.

The androgen receptor (AR) is well known to play a central role in the pathogenesis of prostate cancer (PCa). In several studies, AR was overexpressed in castration-resistant PCa (CRPC). However, the mechanism of AR overexpression in CRPC is not fully elucidated. Y-box binding protein-1 (YB-1) is a pleiotropic transcription factor that is upregulated in CPRC. We aimed to elucidate the role of YB-1 in castration resistance of PCa and identify therapeutic potential of targeting YB-1. Using immunohistochemistry, we found that nuclear YB-1 expression significantly correlated with the Gleason score and AR expression in PCa tissues. In PCa cells, YB-1 regulated AR expression at the transcriptional level. Furthermore, YB-1 expression and nuclear localization were upregulated in CRPC cells. Overexpression of AR, as well as YB-1, conferred castration-resistant growth in LNCaP and 22Rv1 cells. Conversely, knocking down YB-1 resulted in suppressed cell growth and induced apoptosis, which was more efficient than knocking down AR in LNCaP cells. In other types of PCa cells, such as CRPC cells, knocking down YB-1 resulted in a significant reduction of cell growth. In conclusion, these findings suggested that YB-1 induces castration resistance in androgen-dependent PCa cells via AR expression. Thus, YB-1 may be a promising therapeutic target for PCa, as well as CRPC.

Ectonucleoside triphosphate diphosphohydrolase 6 expression in testis and testicular cancer and its implication in cisplatin resistance.

The development of resistance to cisplatin during treatment of testicular cancer constitutes a major obstacle to the cure of testicular cancer. To resolve its mechanism will provide useful information for making clinical decisions. We found 4 and 15 gene expressions were, respectively, up-regulated and down-regulated in cisplatin-resistant testicular cancer NEC-8/DDP cells compared with their parental NEC-8 cells (about 2.5-fold) using cDNA microarray analysis. After screening, we selected the ENTPD6 among these 19 genes. ENTPD6 was less expressed in cancerous region compared with that in non-cancerous lesion. In addition, ENTPD6 expression in seminoma was higher than that in other testicular tumors. ENTPD6 expression was involved in cellular sensitivity to cisplatin through an interaction with E-cadherin. ENTPD6 is a promising molecular biomarker of cisplatin resistance in testicular cancer, and also a novel therapeutical target modulating cisplatin resistance in testicular cancer.

The significance of strong histone deacetylase 1 expression in the progression of prostate cancer.

AIMS: Histone deacetylases (HDACs) play important roles in many types of cancer. Recently, it has been reported that HDAC1 expression in prostate cancer is significantly higher than in benign prostate cell lines and tissues. The expression of HDAC1 in association with the clinicopathological data was investigated to define its functional and pathological roles in prostate cancer. METHODS AND RESULTS: HDAC1 expression was examined immunohistochemically in 148 patients with prostate cancer. Strong expression of HDAC1 in benign prostate glands, high-grade prostatic intraepithelial neoplasia (PIN) and prostate cancer was observed in 17/148 (11%), 19/71 (27%) and 69/148 (47%) patients. Strong HDAC1 expression was correlated with high Gleason score (P = 0.025) and high pT stage (P = 0.012). Patients with strong HDAC1 expression had higher biochemical recurrence rates (P = 0.0010). Furthermore, strong HDAC1 expression had a significant impact on patient biochemical recurrence rates in multivariate analysis (P = 0.004). CONCLUSIONS: These results indicate that overexpression of HDAC1 contributes to progression and poor prognosis in prostate cancer. The findings may play an important role in the emergence of effective new approaches for therapy and prognostic markers of prostate cancer.