Expression In Prostate Cancer Tissues Research Articles

Gamma-glutamyltransferase activity in exosomes as a potential marker for prostate cancer

BackgroundExosomes or extracellular vesicles have the potential as a diagnostic marker for various diseases including cancer. In order to identify novel exosomal markers for prostate cancer (PC), we performed proteomic analysis of exosomes isolated from PC cell lines and examined the usefulness of the marker in patients.MethodsExosomes isolated by differential centrifugation from the culture medium of androgen-dependent LNCaP prostate cancer cell line and its sublines of partially androgen-independent C4, androgen-independent C4–2 and bone metastatic C4–2B were subjected to iTRAQ-based proteomic analysis. Exosomes were also isolated by immunocapture and separated by size exclusion chromatography and density gradient centrifugation. Protein expression was determined by Western blot analysis. GGT activity was measured using a fluorescent probe, γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG). Immunohistochemical analysis of tissues was performed using anti-GGT1 antibody.ResultsAmong proteins upregulated in C4–2 and C4–2B cells than in LNCaP cells, we focused on gamma-glutamyltransferase 1 (GGT1), a cell-surface enzyme that regulates the catabolism of extracellular glutathione. The levels of both GGT1 large and small subunits were elevated in exosomes isolated from C4–2 and C4–2B cells by differential centrifugation and by immunocapture with anti-CD9 or -prostate-specific membrane antigen (PSMA) antibody. In cell lysates and exosomes, GGT1 expression correlated with GGT activity. Size exclusion chromatography of human serum demonstrated the presence of GGT activity and GGT1 subunits in fractions positive for CD9. Density gradient centrifugation revealed the co-presence of GGT1 subunits with CD9 in exosomes isolated by differential centrifugation from human serum. Since GGT activity correlated with GGT1 expression in serum exosomes isolated by differential centrifugation, we measured serum exosomal GGT activity in patients. Unexpectedly, we found that serum exosomal GGT activity was significantly higher in PC patients than in benign prostatic hyperplasia (BPH) patients. In support of this finding, immunohistochemical analysis showed increased GGT1 expression in PC tissues compared with BPH tissues.ConclusionsOur results suggest that serum exosomal GGT activity could be a useful biomarker for PC.

High expression of Rab25 contributes to malignant phenotypes and biochemical recurrence in patients with prostate cancer after radical prostatectomy

BackgroundRas-related protein 25 (Rab25) functions either as an oncogene or a tumor suppressor with a cancer type-dependent manner. We aimed to investigate clinical significance of Rab25 in prostate cancer (PCa).MethodsQuantitative real-time polymerase chain reaction, Western blot and immunohistochemistry were respectively performed to detect Rab25 mRNA and protein expression in PCa and adjacent non-cancerous prostate tissues. Receiver-operating characteristic curve analysis was used to evaluate predictive diagnostic value of Rab25. Associations of Rab25 expression with various clinicopathological characteristics and biochemical recurrence-free survival of PCa patients were statistically evaluated. In vitro, PCa cell proliferation was assessed by CCK-8 assay, and the cell migration and invasion activities were evaluated by Transwell assay, following the transfection of Rab25 small interfering RNA.ResultsRas-related protein 25 mRNA and protein expression in PCa tissues were both significantly higher than adjacent non-cancerous prostate tissues (both P < 0.001). The area under the curve of Rab25 immunoreactive score (IRS) was 0.896 (P < 0.001) with 74.0% sensitivity and 95.0% specificity. High Rab25 IRS was significantly associated with high Gleason score (P = 0.02) and distant metastasis (P = 0.01). PCa patients with high Rab25 IRS had shorter overall and biochemical recurrence-free survivals than those with low Rab25 IRS (both P < 0.001). Cox regression analysis identified Rab25 as an independent biomarker for both overall and biochemical recurrence-free survivals of PCa patients. By exploring its activities in vitro, Rab25 downregulation was found to inhibit PCa cell proliferation, migration and invasion.ConclusionsHigh expression of Rab25 may contribute to malignant progression and biochemical recurrence of PCa patients after radical prostatectomy.

Long noncoding RNA LINC01296 is associated with poor prognosis in prostate cancer and promotes cancer-cell proliferation and metastasis.

Background/purposeLong noncoding RNAs (lncRNAs) have emerged as important regulators and biomarkers of tumor development and progression. This study investigated the clinical significance, biological functions, and underlying mechanisms of long intergenic non-protein-coding RNA 1296 (LINC01296) in prostate cancer.Materials and methodsLINC01296 expression in prostate cancer tissues and cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between LINC01296 expression and clinicopathologic characteristics of prostate cancer was analyzed using Kaplan–Meier analysis and the Cox proportional-hazard model. Small interfering RNA was used to suppress LINC01296, and knockdown efficiency was examined by qRT-PCR. Cell Counting Kit 8 assay, colony-formation assay, migration and invasion assays, and Western blot assay were used to explore the role of LINC01296 in tumor progression further.ResultsLINC01296-expression level was higher in prostate cancer tissues and prostate cancer cells than in adjacent nontumor tissues and immortalized normal prostate stromal WPMY1 cells. LINC01296 expression was correlated with preoperative prostate specific antigen (P=0.002), lymph-node metastasis (P=0.035), Gleason score (P<0.001), and tumor stage (P=0.036). Patients with higher LINC01296 expression displayed advanced clinical features and shorter biochemical recurrence-free survival time than those with lower LINC01296 expression. Multivariate analysis showed that LINC01296 expression was an independent predictor of biochemical recurrence-free survival in prostate cancer. Additionally, LINC01296 knockdown inhibited prostate cancer-cell proliferation, migration, and invasion, demonstrated in an in vitro study involving regulation of PI3K–Akt–mTOR signaling and epithelial–mesenchymal transition.ConclusionThe results demonstrated that LINC01296 is a novel molecule involved in prostate cancer development and progression, and thus is a potential biomarker of prognosis.

Inhibition of DIXDC1 by microRNA-1271 suppresses the proliferation and invasion of prostate cancer cells

Disheveled-Axin domain containing 1 (DIXDC1) is involved in the development and progression of multiple cancers. However, the function significance of DIXDC1 in prostate cancer remains unclear. In this study, we investigated the function of DIXDC1 in prostate cancer and the regulation of DIXDC1 by microRNAs (miRNAs). We found that DIXDC1 was highly expressed in prostate cancer cells. Knockdown of DIXDC1 by small interfering RNAs markedly suppressed proliferation, invasion and Wnt signaling in prostate cancer cells. DIXDC1 was identified as a target gene of miR-1271 by bioinformatics analysis, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction and Western blot analysis. Furthermore, DIXDC1 expression was inversely correlated with miR-1271 expression in prostate cancer tissues. The overexpression of miR-1271 significantly inhibited proliferation, invasion and Wnt signaling in prostate cancer cells. However, the inhibition of miR-1271 exhibits the opposite effects. Moreover, the overexpression of DIXDC1 significantly reversed the inhibitory effects of miR-1271 overexpression. Taken together, our results suggest that DIXDC1 plays an important role in regulating prostate cancer cell proliferation and invasion. Targeting DIXDC1 by miR-1271 may be a promising therapeutic strategy for prostate cancer.

Pyruvate dehydrogenase expression is negatively associated with cell stemness and worse clinical outcome in prostate cancers.

Cells generate adenosine-5′-triphosphate (ATP), the major currency for energy-consuming reactions, through mitochondrial oxidative phosphorylation (OXPHOS) and glycolysis. One of the remarkable features of cancer cells is aerobic glycolysis, also known as the “Warburg Effect”, in which cancer cells rely preferentially on glycolysis instead of mitochondrial OXPHOS as the main energy source even in the presence of high oxygen tension. One of the main players in controlling OXPHOS is the mitochondrial gatekeeperpyruvate dehydrogenase complex (PDHc) and its major subunit is E1α (PDHA1). To further analyze the function of PDHA1 in cancer cells, it was knock out (KO) in the human prostate cancer cell line LnCap and a stable KO cell line was established. We demonstrated that PDHA1 gene KO significantly decreased mitochondrial OXPHOS and promoted anaerobic glycolysis, accompanied with higher stemness phenotype including resistance to chemotherapy, enhanced migration ability and increased expression of cancer stem cell markers. We also examined PDHA1 protein expression in prostate cancer tissues by immunohistochemistry and observed that reduced PDHA1 protein expression in clinical prostate carcinomas was significantly correlated with poor prognosis. Collectively, our results show that negative PDHA1 gene expressionis associated with significantly higher cell stemness in prostate cancer cells and reduced protein expression of this gene is associated with shorter clinical outcome in prostate cancers.

Pim-3 is a Critical Risk Factor in Development and Prognosis of Prostate Cancer.

BackgroundPim-3 kinase is a highly homologous serine/threonine kinase that is overexpressed in hematological malignancies and solid tumors. Few studies have been conducted to define the role of Pim-3 in solid tumors, especially in prostate cancer. The aim of this study was to define the role of Pim-3 in development and prognosis of prostate cancer.Material/MethodsWe collected specimens from 160 patients with prostate cancer, as well as 100 patients with benign prostatic hyperplasia. Realtime polymerase chain reaction was used for the assessment of Pim-3 expression at the RNA level and Western blot was used to quantify the Pim-3 protein synthesis in 3 different cell lines.ResultsWe found that Pim-3 mRNA expression in prostate cancer tissue was significantly higher than that in benign prostatic hyperplasia tissue (p<0.05). Accordingly, the protein level expression of Pim-3 in prostate cancer cell lines was also significantly higher than that in control cells. In addition, the expression status of Pim-3 mRNA was significantly associated with pathological parameters such as pre-surgery prostate specific antigen, Gleason score, pathological stage, and lymphoid metastasis. High expression of Pim-3 also significantly decreased the survival rate of patients after surgery.ConclusionsPim-3 expression is an important risk factor for prostate cancer; we are the first team to report Pim-3 as a valuable biomarker in Chinese.

Protein arginine methyltransferase 5 functions as an epigenetic activator of the androgen receptor to promote prostate cancer cell growth

Protein arginine methyltransferase 5 (PRMT5) is an emerging epigenetic enzyme that mainly represses transcription of target genes via symmetric dimethylation of arginine residues on histones H4R3, H3R8 and H2AR3. Accumulating evidence suggests that PRMT5 may function as an oncogene to drive cancer cell growth by epigenetic inactivation of several tumor suppressors. Here, we provide evidence that PRMT5 promotes prostate cancer cell growth by epigenetically activating transcription of the androgen receptor (AR) in prostate cancer cells. Knockdown of PRMT5 or inhibition of PRMT5 by a specific inhibitor reduces the expression of AR and suppresses the growth of multiple AR-positive, but not AR-negative, prostate cancer cells. Significantly, knockdown of PRMT5 in AR-positive LNCaP cells completely suppresses the growth of xenograft tumors in mice. Molecular analysis reveals that PRMT5 binds to the proximal promoter region of the AR gene and contributes mainly to the enriched symmetric dimethylation of H4R3 in the same region. Mechanistically, PRMT5 is recruited to the AR promoter by its interaction with Sp1, the major transcription factor responsible for AR transcription, and forms a complex with Brg1, an ATP-dependent chromatin remodeler, on the proximal promoter region of the AR gene. Furthermore, PRMT5 expression in prostate cancer tissues is significantly higher than that in benign prostatic hyperplasia tissues, and PRMT5 expression correlates positively with AR expression at both the protein and mRNA levels. Taken together, our results identify PRMT5 as a novel epigenetic activator of AR in prostate cancer. Given that inhibiting AR transcriptional activity or androgen synthesis remains the major mechanism of action for most existing anti-androgen agents, our findings also raise an interesting possibility that targeting PRMT5 may represent a novel approach for prostate cancer treatment by eliminating AR expression.

XB130 is overexpressed in prostate cancer and involved in cell growth and invasion.

XB130 is a cytosolic adaptor protein involved in various physiological processes and oncogenesis of certain malignancies, but its role in the development of prostate cancer remains unclear. In current study, we examined XB130 expression in prostate cancer tissues and found that XB130 expression was remarkably increased in prostate cancer tissues and significantly correlated with increased prostate specific antigen (PSA), free PSA (f-PSA), prostatic acid phosphatase (PAP) and T classification. Patients with highly expressed XB130 had significantly decreased survival, which suggested XB130 as a possible prognostic indicator for prostate cancer. In vitro experiments showed that reduced XB130 expression restrained tumor growth both in vitro and in vivo. Furthermore, XB130 knockdown hindered transition of G1 to S phase in prostate cancer cell line DU145 and LNCap, which might contribute to the inhibition of cellular proliferation. Results from transwell assay demonstrated that downregulation of XB130 may attenuate invasion and metastasis of prostate cancer. Semiquantitative analysis of Western blot suggested that decreased XB130 expression was accompanied by diminished Akt signaling and EMT process. Thus, above observations suggest that XB130 may be a novel molecular marker and potent therapeutic target for prostate cancer.

PYK2 via S6K1 regulates the function of androgen receptors and the growth of prostate cancer cells.

Androgen receptor (AR) is a steroid hormone receptor that functions as a transcription factor for regulating cell growth and survival. Aberrant AR function becomes a risk factor for promoting the progression of prostate cancer (PCa). In this study, we examined the roles of proline-rich tyrosine kinase 2 (PYK2) and ribosomal S6 kinase 1 (S6K1) in regulating AR expression and activity and growth properties in PCa cells. Compared with normal prostate tissues, PCa tumors exhibited high levels of PYK2 and S6K1 expression. Furthermore, the expression levels of PYK2 and S6K1 were significantly correlated with nuclear AR expression in PCa tissues. We further found the association between PYK2, S6K1, and AR in their protein expression and phosphorylation levels among normal prostate PZ-HPV-7 cells and prostate cancer LNCaP and 22Rv1 cells. Overexpression of the wild-type PYK2 in PZ-HPV-7 and LNCaP cells promoted AR and S6K1 expression and phosphorylation as well as enhanced cell growth. In contrast, expression of the mutated PYK2 or knockdown of PYK2 expression in LNCaP or 22Rv1 cells caused reduced expression or phosphorylation of AR and S6K1 as well as retarded cell growth. Under an androgen-deprived condition, PYK2-promoted AR expression and phosphorylation and PSA production in LNCaP cells can be abolished by knocking down S6K1 expression. In summary, our data suggested that PYK2 via S6K1 activation modulated AR function and growth properties in PCa cells. Thus, PYK2 and S6K1 may potentially serve as therapeutic targets for PCa treatment.

Upregulation of Talin-1 expression associates with advanced pathological features and predicts lymph node metastases and biochemical recurrence of prostate cancer

Talin-1 functions to regulate cell–cell adhesion, and its altered expression was reported to be associated with human carcinogenesis.A total of 280 tissue specimens from prostate cancer (PCa) patients who underwent radical prostatectomy, 75 cases of benign prostatic hyperplasia (BPH) tissue, and 6 cases of normal prostate tissue specimens were collected for construction of tissue microarray and subsequently subjected to immunohistochemical staining of Talin-1 expression.Talin-1 expression was significantly higher in PCa than both normal and BPH tissues (P <0.001). Talin-1 expression in PCa tissues was associated with preoperative prostate-specific antigen (PSA) level, Gleason score, tumor stage, lymph node metastasis, positive surgical margin, extracapsular extension and seminal vesicle invasion (all P <0.05). Logistic regression analysis showed that Talin-1 and Gleason score were independent risk factors for lymph node metastasis of PCa (P <0.001). Receiver operating characteristic (ROC) curve indicated that Talin-1 expression (AUC = 0.766) had a better accuracy to predict PCa lymph node metastasis than Gleason score (AUC = 0.697), whereas their combination could further enhance the prediction accuracy (AUC = 0.803). Kaplan–Meier curve analysis showed that increased Talin-1 expression was associated with shortened biochemical-free survival of PCa patients after radical prostatectomy (P <0.001).These findings suggested that Talin-1 protein was significantly upregulated in PCa tissues compared with that of BPH tissue and Talin-1 expression was an independent predictor for lymph node metastasis and biochemical recurrence of PCa. Further study will investigate the underlying molecular mechanism and the role of Talin-1 in PCa.

Nemo-like kinase as a negative regulator of nuclear receptor Nurr1 gene transcription in prostate cancer.

BackgroundNurr1, a member of the orphan receptor family, plays an important role in several types of cancer. Our previous work demonstrated that increased expression of Nurr1 plays a significant role in the initiation and progression of prostate cancer (PCa), though the mechanisms for regulation of Nurr1 expression remain unknown. In this study, we investigated the hypothesis that Nemo-like kinase (NLK) is a key regulator of Nurr1 expression in PCa.MethodsImmunohistochemistry and Western blot analysis were used to evaluate levels of NLK and Nurr1 in prostatic tissues and cell lines. The effects of overexpression or knockdown of Nurr1 were evaluated in PCa cells through use of PCR, Western blots and promoter reporter assays. The role of Nurr1 promoter cis element was studied by creation of two mutant Nurr1 promoter luciferase constructs, one with a mutated NF-κB binding site and one with a mutated CREB binding site. In addition, three specific inhibitors were used to investigate the roles of these proteins in transcriptional activation of Nurr1, including BAY 11–7082 (NF-κB inhibitor), KG-501 (CREB inhibitor) and ICG-001 (CREB binding protein, CBP, inhibitor). The function of CBP in NLK-mediated regulation of Nurr1 expression was investigated using immunofluorescence, co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation assays (ChIPs).ResultsNLK expression was inversely correlated with Nurr1 expression in prostate cancer tissues and cell lines. Overexpression of NLK suppressed Nurr1 promoter activity, leading to downregulation of Nurr1 expression. In contrast, knockdown of NLK demonstrated opposite results, leading to upregulation of Nurr1. When compared with the wild-type Nurr1 promoter, mutation of NF-κB- and CREB-binding sites of the Nurr1 promoter region significantly reduced the upregulation of Nurr1 induced by knockdown of NLK in LNCaP cells; treatment with inhibitors of CREB, CBP and NF-κB led to similar results. We also found that NLK directly interacts with CBP, that knockdown of NLK significantly increases the recruitment of CBP to both NF-κB- and CREB-binding sites, and that regulation of NLK on Nurr1 expression is abrogated by knockdown of CBP.ConclusionsOur results suggest that NLK inhibits transcriptional activation of Nurr1 gene by impeding CBP’s role as a co-activator of NF-κB and CREB in prostate cancer.

Downregulation of cytokeratin 18 is associated with paclitaxel‑resistance and tumor aggressiveness in prostate cancer.

Paclitaxel frequently serves as the first-line chemotherapeutic agent for castration-resistant prostate cancer (PCa) patients. However, acquired paclitaxel-resistance almost always occurs after initial responses, and the mechanisms by which this occurs remain largely unknown. The goal of the present study was to identify differentially expressed protein(s) associated with paclitaxel-resistance and further explore the potential mechanisms involved in drug resistance. By comparing the nuclear matrix protein (NMP) patterns of DU145-TxR cells, the previously established stable paclitaxel-resistant PCa cells, with that of the parental DU145 cells using two-dimensional electrophoresis, we found that cytokeratin 18 (CK18) is downregulated in DU145-TxR cells. The downregulation of CK18 in DU145-TxR cells at mRNA, NMP and total cellular protein levels was validated by real-time RT-PCR, immunoblotting and immunofluorescence, indicating that the downregulation of CK18 was a global effect in DU145-TxR cells due to paclitaxel-resistance. Furthermore, in vivo assay of xenograft transplantation confirmed the higher tumorigenicity of DU145-TxR cells, suggesting that these paclitaxel-resistant PCa cells possessed potent cancer stem cell (CSC)-like properties and eventually developed paclitaxel-resistance. Moreover, we determined by immunohistochemistry that CK18 expression in PCa tissues was inversely correlated with tumor grade in a statistically significant fashion, indicating a potential association of the downregulation of CK18 with tumor aggressiveness. Therefore, further study to define the potential role of CK18 may lead to novel therapy strategies as well as clinically useful biomarker for PCa patients.

Protein regulator of cytokinesis 1 overexpression predicts biochemical recurrence in men with prostate cancer.

Protein regulator of cytokinesis 1 (PRC1) has been reported to be implicated into the completion of cytokinesis and is dys-regulated in a cancer-specific manner. However, it roles in human prostate cancer (PCa) remain unclear. In the current study, we aimed to investigate the expression pattern of PRC1 and its clinical significance in this malignancy. PRC1 protein expression in human PCa and non-cancerous prostate tissues was detected by immunohistochemistry, which was validated by microarray-based Taylor data at mRNA level. Then, the associations of PRC1 expression with clinicopathological features and clinical outcome of PCa patients were statistically analyzed. PRC1 expression in PCa tissues, at both mRNA and protein levels, were significantly higher than those in non-cancerous prostate tissues. In addition, the PCa patients with PRC1 overexpression more frequently had high Gleason score, advanced pathological stage, positive metastasis, short overall survival time and positive PSA failure than those with low Gleason score, early pathological stage, negative metastasis, long overall survival time and negative PSA failure (all P<0.05). Moreover, PRC1 expression was identified as an unfavorable prognostic factor of biochemical recurrence-free survival in PCa patients (P<0.001). These findings suggest that the aberrant expression of PRC1 may predict biochemical recurrence in men with PCa highlighting its potential as a prognostic marker of this malignancy.

CXCR6-CXCL16 axis promotes prostate cancer by mediating cytoskeleton rearrangement via Ezrin activation and αvβ3 integrin clustering.

Cytoskeletal rearrangement is required for migration and invasion, which are the key steps of cancer metastasis. Ezrin and integrin co-ordinate these processes by regulating cellular adhesion and cytoskeletal polymerization-depolymerization. It is also well established that chemokine-chemokine receptor axis plays a crucial role in regulating cancer cell migration and invasion. In this study, we show involvement of CXC chemokine receptor 6 (CXCR6) and its only natural ligand CXCL16 in pathobiology of prostate cancer (PCa). CXCR6 is highly expressed in PCa tissues and cell lines (LNCaP and PC3), relative to normal tissue and cells. CXCR6 expression in PCa tissues correlated with higher Gleason score. Similarly, aggressive PCa cells (PC3) show high CXCR6 compared to less aggressive LNCaP. Besides, PC3 cells show higher MMPs expression compared to LNCaP cells following CXCL16 stimulation. Intriguingly, CXCR6-CXCL16 interaction in PCa cells promotes Ezrin activation, αvβ3 integrin clustering and capping at the leading edge in FAK/PI3K/PKC dependent manner, thereby modifying cellular adhesion as well as motility. Together these results demonstrate that CXCL16 stimulation changes cytoskeletal dynamics resulting in enhanced migration, invasion and adhesion to endothelial cells, ultimately enabling PCa cells to achieve their metastatic goal.

Intracellular location of BRCA2 protein expression and prostate cancer progression in the Swedish Watchful Waiting Cohort.

Prostate cancer patients with inherited BRCA2 mutations have a survival disadvantage. However, it is unknown whether progression is associated with BRCA2 protein expression in diagnostic prostate cancer tissue, among men without inherited mutations. We conducted a nested case-control study within the Swedish Watchful Waiting cohort. The case group included all 71 patients who died from prostate cancer within 5 years from diagnosis and controls were all patients (n = 165) who lived at least 7 years after diagnosis. Tissue microarrays were stained using antibodies for C- and N-terminal domains of the BRCA2 protein. Location (nuclear, cytoplasmic and membranous) and magnitude (intensity and percentage) of expression were assessed. Logistic regression models produced odds ratios (OR) and 95% confidence intervals (CI) adjusted for age, year of diagnosis and Gleason score. Positive BRCA2 staining at the cell membrane was associated with reduced risk of death within 5 years (N-terminal: OR = 0.47, 95% CI = 0.21-1.04, P = 0.06; C-terminal: OR = 0.41, 95% CI = 0.18-0.91, P = 0.03) and low Gleason scores (P = 0.006). Positive cytoplasmic C-terminal staining was associated with higher Gleason scores and increased lethality (OR = 3.61, 95% CI = 1.61-8.07, P = 0.002). BRCA2 protein expression at the cell membrane and lack of C-terminal expression in the cytoplasm were associated with a reduced risk of rapidly fatal prostate cancer. BRCA2 protein expression in prostate cancer tissue may have independent prognostic value. The potential biological significance of BRCA2 expression at the cell membrane warrants further investigation.

Prognostic value of ZFP36 and SOCS3 expressions in human prostate cancer.

ZFP36 ring finger protein (ZFP36) and the suppressor of cytokine signaling 3 (SOCS3) have been reported to, respectively, regulate NF-κB and STAT3 signaling pathways. To better understand the correlation of NF-κB and STAT3 negative regulates pathway, we have investigated the involvement of ZFP36 and SOCS3 expressions in human prostate cancer (PCa). In the present study, paired patient tissue microarrays were analyzed by immunohistochemistry, and the ZFP36 protein expression was quantitated as immunoreactive scores in patients with PCa. Associations between ZFP36/SOCS3 expression and various clinicopathological features and prognosis of PCa patients were statistically analyzed based on the Taylor database. Then, the functions of ZFP36 and SOCS3 in cancerous inflammation were determined using qPCR and immunohistochemistry in vitro and in vivo. ZFP36 protein expression in PCa tissues was significantly lower than those in non-cancerous prostate tissues (P<0.05). In mRNA level, ZFP36 and SOCS3 had a close correlation with each other (P<0.01, Pearson r=0.848), and its upregulation was both significantly associated with low Gleason score (P<0.001 and P<0.001, respectively), negative metastasis (P<0.001 and P<0.001, respectively), favorable overall survival (P<0.001 and P<0.05, respectively), and negative biochemical recurrence (P<0.001 and P<0.001, respectively). Functionally, LPS treatment could lead to the overexpression of ZFP36 and SOCS3 in vitro and vivo. Our data offer the convincing evidence for the first time that the aberrant expressions of ZFP36 and SOCS3 may be involved into the progression and patients' prognosis of PCa, implying their potentials as candidate markers of this cancer.

Correlation between Microvascular Density and Matrix Metalloproteinase 11 Expression in Prostate Cancer Tissues: a Preliminary Study in Thailand.

Prostate cancer is a major concern of public health. Microvascular density (MVD) is one of the prognostic markers for various solid cancers. Matrix metalloproteinase 11 (MMP11) plays an important role in angiogenesis and changes in its expression level are known to be associated with tumor progression and clinical outcome. To investigate the relationship between MVD and MMP11 expression in prostatic adenocarcinoma tissues. The expression levels of MMP11 and MVD were analyzed immunohistochemically for 50 specimens of prostatic adenocarcinoma. MMP11 was mainly expressed in stromal cells but rarely seen in epithelial cells. Mean MVD was 36/mm2, and it was correlated significantly only with bone metastases. MVD was also significantly correlated with MMP11 expression (r=0.29, p=0.044). MMP11 may alter the stromal microenvironment of prostate cancer to stimulate tumor angiogenesis.

MicroRNA-340 Suppresses Tumorigenic Potential of Prostate Cancer Cells by Targeting High-Mobility Group Nucleosome-Binding Domain 5.

Aberrantly expressed microRNAs (miRs) are extensively involved in tumorigenesis. microRNA-340 (miR-340) has been reported as a tumor suppressor in various cancer types. However, whether miR-340 plays an important role in prostate cancer remains unknown. This study aims to investigate the expression pattern of miR-340 and its functional significance in prostate cancer. Results showed that miR-340 expression was frequently downregulated in human prostate cancer cell lines and cancer tissues. miR-340 overexpression suppressed proliferative and invasive properties of prostate cancer cells. This overexpression also promoted prostate cancer cell apoptosis. Conversely, miR-340 silencing showed an opposite effect. Intriguingly, on the basis of bioinformatics analysis and luciferase reporter assay, we found that miR-340 directly targeted the 3'-untranslated region of the high-mobility group nucleosome-binding domain 5 (HMGN5). Quantitative polymerase chain reaction and western blot analysis further verified the results and demonstrated that miR-340 regulated HMGN5 expression. Correlation analysis also showed that HMGN5 expression levels were significantly inversely correlated with the miR-340 expression in prostate cancer tissues. Furthermore, miR-340 overexpression significantly decreased the protein expression of cyclin B1, Bcl-2, and matrix metalloproteinase-9, which are critical regulators for maintaining tumorigenic potential of cancer cells. In addition, overexpression of HMGN5 significantly reversed the inhibitory effect of miR-340 on prostate cancer cell proliferation and invasion. In summary, this study suggests that miR-340 suppresses the tumorigenic potential of prostate cancer cells. Moreover, the decreased miR-340 expression may contribute to the development and progression of prostate cancer through a mechanism that involves HMGN5. Thus, miR340 and its target gene HMGN5 can serve as potentially useful therapeutic candidates for prostate cancer treatment.

MiR-34a inhibits cell proliferation in prostate cancer by downregulation of SIRT1 expression.

MicroRNA-34a (miR-34a) functions as a tumor suppressor gene and inhibits abnormal cell growth by regulating the expression of other genes. The role of miR-34a in regulating sirtuin 1 (SIRT1) in prostate cancer remains unclear. The objective of the present study was to investigate the biological function and molecular mechanisms of miR-34a regulation of SIRT1 in human prostate cancer samples and the human prostate cancer cell line, PC-3. Fresh prostate tissues were obtained from patients, and the miR-34a expression in prostate cancer tissues was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). qPCR and western blotting were performed to assess the effects of miR-34a overexpression on SIRT1 regulation in PC-3 cells, and the cell growth was assessed by Cell Counting Kit-8 (CCK-8). Flow cytometry was used to assess the cell cycle status of the cells. The miR-34a expression levels in prostate cancer tissues were significantly reduced compared with adjacent normal prostate tissues (P<0.05). SIRT1 expression levels in PC-3 cells with over-expression of miR-34a were significantly reduced compared with those in the negative control (P<0.05). The over-expression of miR-34a inhibited PC-3 cells growth and resulted in increased cell cycle arrest compared with the negative control (P<0.05). In conclusion, miR-34a inhibits the human prostate cancer cell proliferation, in part, through the downregulation of SIRT1 expression.

PIAS1 is a determinant of poor survival and acts as a positive feedback regulator of AR signaling through enhanced AR stabilization in prostate cancer.

Novel drugs like Abiraterone or Enzalutamide, which target androgen receptor (AR) signaling to improve androgen deprivation therapy (ADT), have been developed during the past years. However, the application of these drugs is limited because of occurrence of inherent or acquired therapy resistances during the treatment. Thus, identification of new molecular targets is urgently required to improve current therapeutic prostate cancer (PCa) treatment strategies. PIAS1 (protein inhibitor of activated STAT1 (signal transducer and activator of transcription-1)) is known to be an important cell cycle regulator and PIAS1-mediated SUMOylation is essential for DNA repair. In this context, elevated PIAS1 expression has already been associated with cancer initiation. Thus, in the present study, we addressed the question of whether PIAS1 targeting can be used as a basis for an improved PCa therapy in combination with anti-androgens. We show that PIAS1 significantly correlates with AR expression in PCa tissue and in cell lines and demonstrate that high PIAS1 levels predict shorter relapse-free survival. Our patient data are complemented by mechanistic and functional in vitro experiments that identify PIAS1 as an androgen-responsive gene and a crucial factor for AR signaling via prevention of AR degradation. Furthermore, PIAS1 knockdown is sufficient to decrease cell proliferation as well as cell viability. Strikingly, Abiraterone or Enzalutamide treatment in combination with PIAS1 depletion is even more effective than single-drug treatment in multiple PCa cell models, rendering PIAS1 as a promising target protein for a combined treatment approach to improve future PCa therapies.