Genome-Wide CRISPR-Cas9 Screening and Identification of Potential Genes Promoting Prostate Cancer Growth and Metastasis.

OBJECTIVE: Identification and validation of genes that functionally account for the growth and metastasis of prostate cancer. METHODS: DU145-KO cell line was constructed by transfecting DU145 cells with lentivirus packaged with the genome-wide knock-out library. The DU145-KO cells were transplanted into the armpits of immunocompromised Nu/Nu mice, followed by the tissue collection from the lung at week 3 (early lung tissue) or week 7 (late lung tissue with micro-metastasis), as well as from primary tumor site at week 7 (late primary tumor) after inoculation. Lung metastasis was retrieved at various time points for DNA sequencing analysis to identify enriched sgRNAs, thus candidate genes/miRNAs. Further bioinformatics analysis and limited functional validation studies were carried out. RESULTS: DU145-KO cells promoted the formation of transplanted tumors in mice and promoted the growth and metastasis of primary tumors, compared to the controls (DU145-NC cells). The analysis of sequence data showed that the abundance of sgRNAs significantly changed in the primary tumor and micro-metastasis site. Fifteen target genes (C1QTNF9B, FAM229A, hsa-mir-3929, KRT23, TARS2, CRADD, GRIK4, PLA2G15, LOXL1, SLITRK6, CDC42EP5, SLC2A4, PTGDS, MYL9 and ACOX2 for the enriched sgRNAs) have been selected for experimental validation, which showed that knock-out of any of these genes led to the enhanced potential of invasion and metastasis of DU145 cells. CONCLUSION: Genome-wide CRISPR-Cas9 knock-out screening technology combined with highthroughput sequencing analysis identified genes that potentially relate to prostate tumor invasion and metastasis. Analysis of these genes provided insights into biological pathways relevant to the disease and disclosed innovative markers for diagnosis or prognosis as well as potential targets for therapy.

CRISPR/Cas9 (D10A) nickase-mediated Hb CS gene editing and genetically modified fibroblast identification.

This study investigated whether CRISPR/Cas9 (D10A) nickase-mediated gene editing can correct the aberrant Hb Constant Spring mutation (Hb CS or HBA2: c.427 T > C) in fibroblasts. Vectors for repairing the α-globin-encoding gene, HBA2:c.427 T > C mutation, includingthe CRISPR/Cas9(D10A)-sg plasmid and donor with homology arms, were constructed and used to perform gene editing in patient-derived fibroblasts. We subsequently analyzed the genetic correction, the gene editing efficiency and off-target effect. Sequencing analysis and the BamHI assay showed that HB CS mutant cells were repaired with Hb CS point mutations, the editing efficiency was 4.18%~9.34% and no off-target effects were detected. The results indicate that the HB CS mutant gene is effectively repaired by the CRISPR/Cas9 (D10A)system, which may enable truly personalized therapy for precise repair of α-thalassemia.

Functional classification of prostate cancer­associated miRNAs through CRISPR/Cas9­mediated gene knockout.

The aim of the present study was to use the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR­associated (Cas) 9­mediated gene knockout technology for the rapid classification of the differential function of micro (mi)RNAs screened using miRNA expression profiling by microarray. The rational design of single guide RNAs for the CRISPR/Cas9 system was verified to function in human LNCaP cells with rapid and efficient target gene editing. miRNA (miR)­205, miR­221, miR­222, miR­30c, miR­224, miR­455­3p, miR­23b and miR­505 were downregulated in patients with prostate cancer (PCa) and were experimentally validated to function as tumor suppressors in prostate cancer cells, affecting tumor proliferation, invasion and aerobic glycolysis. In addition, the data of the present study suggested that miR­663a and mfiR­1225­5p were upregulated in prostate cancer tissues and cell proliferation of miR­663a and miR­1225­5p knockout PCa cells was significantly lower compared with miR­NC cells. Furthermore, knockout of miR­1225­5p and miR­663a significantly decreased the lactate production in LNCaP cells in vitro. In conclusion, the present study offered a simple and efficient method for rapidly classifying miRNA function by applying CRISPR/Cas9 in LNCaP cells. The present study suggested, for the first time to the best of the authors' knowledge, that the aberrant expression of miR­663a and miR­1225­5p may be involved with the progression of prostate cancer, implying their potential as candidate markers for this type of cancer. However, the precise role of miR­663a and miR­1225­5p in accelerating the development of prostate cancer and promoting tumor progression remains to be elucidated.

The study of multiple diagnosis models of human prostate cancer based on Taylor database by artificial neural networks.

BACKGROUND: Prostate cancer (PCa) is the most common malignancy seen in men and the second leading cause of cancer-related death in males. The incidence and mortality associated with PCa has been rapidly increasing in China recently. METHODS: Multiple diagnostic models of human PCa were developed based on Taylor database by combining the artificial neural networks (ANNs) to enhance the ability of PCa diagnosis. Genetic algorithm (GA) is used to select feature genes as numerical encoded parameters that reflect cancer, metastatic, or normal samples. Back propagation (BP) neural network and learning vector quantization (LVQ) neural network were used to build different Cancer/Normal, Primary/Metastatic, and Gleason Grade diagnostic models. RESULTS: The performance of these modeling approaches was evaluated by predictive accuracy (ACC) and area under the receiver operating characteristic curve (AUC). By observing the statistically significant parameters of the three training sets, our Cancer/Normal, Primary/Metastatic, and Gleason Grade models' with ACC and AUC can be drawn (97.33%, 0.9832), (99.17%, 0.9952), and (90.48%, 0.8742), respectively. CONCLUSION: These results indicated that our diagnostic models of human PCa based on Taylor database combining the feature gene expression profiling data and artificial intelligence algorithms might act as a powerful tool for diagnosing PCa. Gleason Grade diagnostic models were used as novel prognostic diagnosis models for biochemical recurrence-free survival and overall survival, which might be helpful in the prognostic diagnosis of PCa in patients.

Increasing of FKBP9 can predict poor prognosis in patients with prostate cancer.

BACKGROUND: FK506 binding protein 9 (FKBP9) has been reported and identified for a long time, but its relationship with cancer is rarely studied. For example, the role of FK506 binding protein 9 in prostate cancer (PCa) is still unclear. Therefore, we decided to detect the expression level of FKBP9 in PCa and explore its clinical significance. METHODS: The expression level of FKBP9 protein was detected by immunohistochemistry. In addition, it was demonstrated by high-throughput sequencing of mRNA levels in the TCGA (cancer genome atlas) dataset of 499 patients. Kaplan-meier analysis and Cox proportional hazard regression model were used to evaluate the relationship between FKBP9 expression and survival in prostate cancer patients. RESULTS: The expression of FKBP9 was localized in the cytoplasm, which in normal prostate tissues was obviously lower than that in PCa tissues (P = 0.001). High expression of FKBP9 was related with lymph node metastasis (P = 0.022) and distant metastasis (P = 0.028). Kaplan-Meier survival analysis revealed that the BCR-free survival of PCa patients with high FKBP9 level was significantly shortened (P=0.041). CONCLUSIONS: FKBP9 may be a cancer promoter that enhances PCa progression, and the level of FKBP9 may be used as an independent precursor of PCa patients.

Correction to: MicroRNA-30d promotes angiogenesis and tumor growth via MYPT1/c-JUN/VEGFA pathway and predicts aggressive outcome in prostate cancer.

After publication of the article [1], the author reported that this article contained some errors.

Increased intracellular Cl- concentration mediates Trichomonas vaginalis-induced inflammation in the human vaginal epithelium.

Trichomonas vaginalis is a primary urogenital parasite that causes trichomoniasis, a common sexually transmitted disease. As the first line of host defense, vaginal epithelial cells play critical roles in orchestrating vaginal innate immunity and modulate intracellular Cl- homeostasis via the cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel that plays positive roles in regulating nuclear factor-κB (NF-κB) signalling. However, the association between T. vaginalis infection and intracellular Cl- disequilibrium remains elusive. This study showed that after T. vaginalis infection, CFTR was markedly down-regulated by cysteine proteases in vaginal epithelial cells. The intracellular Cl- concentration ([Cl-]i) was consequently elevated, leading to NF-κB signalling activation via serum- and glucocorticoid-inducible kinase-1. Moreover, heightened [Cl-]i and activated NF-κB signalling could be sustained in a positive feedback regulatory manner resulting from decreased intracellular cAMP through NF-κB-mediated up-regulation of phosphodiesterase 4. The results conclusively revealed that the intracellular Cl- of the human vaginal epithelium could be dynamically modulated by T. vaginalis, which contributed to mediation of epithelial inflammation in the human vagina.

Expression of PD-L1 in tumor-associated nerves correlates with reduced CD8+ tumor-associated lymphocytes and poor prognosis in prostate cancer.

To investigate immune profile consisting of stromal PD-L1 expression, inhibitory or non-T-cell inflamed tumor microenvironment that may predict response to anti-PD-L1/PD-1 immunotherapy in prostate cancer, we validated the specificity of a PD-L1 monoclonal antibody (E1L3N) and identified PD-L1 specific expression in prostatic stromal nerve cells. PD-L1 expression was analyzed in 73 primary prostate cancers and 7 castration-resistant prostate cancers (CRPC) by immunohistochemistry (IHC) and resulting data from primary prostate cancers were correlated with tumor-associated lymphocytes (TALs), clinicopathological characteristics and clinical outcome. PD-L1 was expressed in the tumor cells in only one primary prostate cancer case and none of the CRPC. However, PD-L1 was frequently observed in the nerve branches in the tumor-associated stroma (69 of 73 cases, 94.5%), supported by colocalization with axonal marker PGP9.5. FoxP3-, CD3- and CD8-positive T lymphocytes were observed in 74.6% (47/63), 98.4% (62/63) and 100% (61/61) of the cases, respectively. The density of PD-L1+ tumor-associated nerves (TANs) was inversely correlated with that of CD8+ TALs. Higher density of PD-L1+ TANs was significantly associated with biochemical recurrence (BCR) in Kaplan-Meier survival analysis (p = 0.016). In both univariate and multivariate Cox analysis, the density of PD-L1+ TANs was independently prognostic of BCR. In conclusion, PD-L1 expression is rare in prostate tumor cells but prevalent in TANs and negatively correlated with CD8+ TALs. Neuro-immunological interaction may be a contribution to immune-suppressive microenvironment. Combinatorial treatment regimen designs to neural PD-L1 and TALs should be warranted in future clinical application of anti-PD-L1/PD-1 immunotherapy in prostate cancer.

Overexpression of TPX2 is associated with progression and prognosis of prostate cancer.

Targeting protein for Xenopus kinesin-like protein 2 (TPX2) activates Aurora kinase A during mitosis and targets its activity to the mitotic spindle, serving an important role in mitosis. It has been associated with different types of cancer and is considered to promote tumor growth. The aim of the present study was to explore the role of TPX2 in diagnosing prostate cancer (PCa). It was identified that TPX2 expression in PCa tissues was increased compared with benign prostate tissues. Microarray analysis demonstrated that TPX2 was positively associated with the Gleason score, tumor-node-metastasis (TNM) stage, clinicopathological stage, metastasis, overall survival and biochemical relapse-free survival. In vitro studies revealed that the high expression of TPX2 in PCa cells improved proliferative, invasive and migratory abilities, and repressed apoptosis of the PCa cells, without affecting tolerance to docetaxel. The results suggested that TPX2 serves as a tumorigenesis-promoting gene in PCa, and a potential therapeutic target for patients with PCa.

BACH1 promotes the progression of human colorectal cancer through BACH1/CXCR4 pathway.

The present study was to investigate clinical significance, biological functions and underlying mechanisms of BTB Domain and CNC Homolog 1(BACH1) deregulation in human colorectal cancer (CRC). The result showed that BACH1 upregulation was significantly associated with enhanced tumor invasion (P = 0.014) and gender (P = 0.028) of CRC patients. Kaplan-Meier method results showed that the overall survival of CRC patients with high BACH1 mRNA expression was markedly shorter than those with low expression (P = 0.015), and multivariate analyzes results showed that BACH1 was an independent prognostic predictor for CRC patients (P = 0.049). In vitro studies revealed that BACH1 efficiently promoted invasion and migration of CRC cell line. In vitro studies proved that the HCT116 cell stably expressing BACH1 formed significantly larger tumor nodules and remarkably accelerated tumor xenografts growth. In addition, Immunohistochemical scores of CD31 and Vimentin were significantly higher than those of the control group. Finally, correlation analysis indicated that BACH1 expression was positively correlated with C-X-C Motif Chemokine Receptor 4(CXCR4) in tumor tissues and cell lines. Together, BACH1 serves as an oncogene to promote CRC progression and an independent prognostic factor for survival and metastasis. BACH1 may inhibit the progression of CRC through BACH1/CXCR4 pathway.

SOCS6 Functions as a Tumor Suppressor by Inducing Apoptosis and Inhibiting Angiogenesis in Human Prostate Cancer.

BACKGROUND: Our previous studies revealed that the downregulation of Suppressor of cytokine signaling 6 (SOCS6) was correlated with malignant progression of human prostate cancer (PCa). AIMS: In the current study, we aimed to investigate the tumor suppressive roles of SOCS6 and the underlying mechanisms in PCa. METHODS: SOCS6 expression in PCa and non-cancerous prostate tissues was compared by immunohistochemistry. Statistical associations of SOCS6 expression with various clinicopathological features and patients prognosis were evaluated. In addition, we investigated SOCS6's functions by overexpressing it in vitro (cell apoptosis, migration and invasion assays) and in vivo (tumor formation, angiogenesis and apoptosis). Moreover, SOCS6-regulated genes were identified by nextgeneration RNA-sequencing analysis, followed by pathway enrichment analysis and in vitro experimental validation. RESULTS: SOCS6 downregulation was significantly associated with advanced clinical stage (P=0.029) and positive lymph node metastasis (P=0.013) in PCa patients. We also identified SOCS6 as an independent prognostic factor for disease-free survival in PCa patients (P=0.045). Moreover, overexpression of SOCS6 inhibited PCa cell invasion, migration, tumor xenografts growth and angiogenesis, but induced PCa cell apoptosis (P values <0.05). Mechanically, we revealed that SOCS6 expression may induce cell apoptosis coincident with down-regulation of Bcl2 and Hspa1a, and may suppress tumor angiogenesis with downregulation of F7, Fak3 and Frzb. CONCLUSION: These findings suggest that the reduced expression of SOCS6 may be predictive of unfavorable prognosis in PCa. Thus, SOCS6 may serve as a tumor suppressor and a novel therapeutic target for this cancer.

Elevated Expression of DLG1 Is Associated with Poor Prognosis in Patients with Colorectal Cancer.

AIMS AND BACKGROUND: Discs large homolog 1 (DLG1) belongs to the modular proteins Membrane Associated Guanylate Kinases (MAGUKs) and plays a major role in the formation of cell-cell junctions and cell polarity. DLG1 varies in expression and localization among malignancies. However, the clinical significance of DLG1 in the context of human colorectal cancer (CRC) remains unclear. The purpose of this study study is to determine the association of DLG1 with clinicopathological characteristics and prognosis of CRC patients. METHODS: DLG1 expression in human CRC was detected by immunohistochemical analysis and validated with mRNA data from a high-throughput sequencing TCGA datasets. The association of DLG1 expression with clinicopathological features in CRC patients was then statistically analyzed. RESULTS: Immunohistochemistry analysis found that DLG1 expression was significantly elevated in CRC tissues, compared with the expression in adjacent non-cancerous colon tissues (P=0.000). High DLG1 expression was significantly associated with advanced clinical stage (P=0.011) and enhanced tumor invasion (P=0.002). The TCGA mRNA expression data revealed that DLG1 mRNA expression was up-regulated in CRC tissues with advanced clinical stage (P=0.008), enhanced tumor invasion (P=0.042), lymph node metastasis (P=0.030), and distant metastasis (P=0.043). Kaplan-Meier survival curves revealed that CRC patients with high DLG1 levels had shorter survival (P=0.040). Furthermore, DLG1 was an independent prognostic factor for CRC patients (HR 2.202, 95% CI 1.057-4.587; P=0.035). CONCLUSIONS: These findings suggest that the increased expression of DLG1 may be predictive of an unfavorable prognosis in CRC patient and serve as a novel therapeutic target in this malignancy.

Role of GPR30 in estrogen-induced prostate epithelial apoptosis and benign prostatic hyperplasia.

Several studies have implicated estrogen and the estrogen receptor (ER) in the pathogenesis of benign prostatic hyperplasia (BPH); however, the mechanism underlying this effect remains elusive. In the present study, we demonstrated that estrogen (17ß-estradiol, or E2)-induced activation of the G protein-coupled receptor 30 (GPR30) triggered Ca2+ release from the endoplasmic reticulum, increased the mitochondrial Ca2+ concentration, and thus induced prostate epithelial cell (PEC) apoptosis. Both E2 and the GPR30-specific agonist G1 induced a transient intracellular Ca2+ release in PECs via the phospholipase C (PLC)-inositol 1, 4, 5-triphosphate (IP3) pathway, and this was abolished by treatment with the GPR30 antagonist G15. The release of cytochrome c and activation of caspase-3 in response to GPR30 activation were observed. Data generated from the analysis of animal models and human clinical samples indicate that treatment with the GPR30 agonist relieves testosterone propionate (TP)-induced prostatic epithelial hyperplasia, and that the abundance of GPR30 is negatively associated with prostate volume. On the basis of these results, we propose a novel regulatory mechanism whereby estrogen induces the apoptosis of PECs via GPR30 activation. Inhibition of this activation is predicted to lead to abnormal PEC accumulation, and to thereby contribute to BPH pathogenesis.

MicroRNA-30d promotes angiogenesis and tumor growth via MYPT1/c-JUN/VEGFA pathway and predicts aggressive outcome in prostate cancer.

BACKGROUND: Even though aberrant expression of microRNA (miR)-30d has been reported in prostate cancer (PCa), its associations with cancer progression remain contradictory. The aim of this study was to investigate clinical significance, biological functions and underlying mechanisms of miR-30d deregulation in PCa. METHODS: Involvement of miR-30d deregulation in malignant phenotypes of PCa was demonstrated by clinical sample evaluation, and in vitro and in vivo experiments. The mechanisms underlying its regulatory effect on tumor angiogenesis were determined. RESULTS: miR-30d over-expression was observed in both PCa cells and clinical specimens. High-miR-30d was distinctly associated with high pre-operative PSA and Gleason score, advanced clinical and pathological stages, positive metastasis and biochemical recurrence (BCR), and reduced overall survival of PCa patients. Through gain- and loss-of-function experiments, we found that miR-30d promoted PCa cell proliferation, migration, invasion, and capillary tube formation of endothelial cells, as well as in vivo tumor growth and angiogenesis in a mouse model. Simulation of myosin phosphatase targeting subunit 1 (MYPT1), acting as a direct target of miR-30d, antagonized the effects induced by miR-30d up-regulation in PCa cells. Notably, miR-30d/MYPT1 combination was identified as an independent factor to predict BCR of PCa patients. Furthermore, miR-30d exerted its pro-angiogenesis function, at least in part, by inhibiting MYPT1, which in turn, increased phosphorylation levels of c-JUN and activated VEGFA-induced signaling cascade in endothelial cells. CONCLUSIONS: miR-30d and/or its target gene MYPT1 may serve as novel prognostic markers of PCa. miR-30d promotes tumor angiogenesis of PCa through MYPT1/c-JUN/VEGFA pathway.

Expression and Clinical Significance of SOX9 in Renal Cell Carcinoma, Bladder Cancer and Penile Cancer.

BACKGROUND: Novel molecular markers are important diagnostic tools for the assessment of cancer progression and evaluation of effectiveness of the treatment. SOX9, a key regulator of developmental processes, is overexpressed in various neoplasms, such as prostate, breast, and colorectal cancers. However, the utilization of SOX9 as a biomarker for other urological cancers has not yet been investigated. METHODS: In the present study, paired patient tissue microarrays were analyzed by immunohistochemistry, and the SOX9 protein expression was quantitated as immunoreactive scores in patients with renal cell carcinoma (RCC), bladder cancer (BCa), and penile cancer (PC). RESULTS: In comparison with normal tissues, SOX9 protein expression was significantly upregulated in RCC (p < 0.001) and BCa (p < 0.001), and significantly correlated with the advanced pathological grade (RCC: p = 0.023) and clinical stage (RCC: p = 0.022 and BCa: p = 0.046) of patients. Based on the mRNA level in the TCGA dataset, SOX9 was upregulated in RCC with gender (p = 0.027), advanced pathological grade (p = 0.003) and advanced clinical stage (p = 0.001). Kaplan-Meier survival curves revealed that RCC patients with high SOX9 levels had shorter survival (p < 0.001). Further, high SOX9 expression was an independent prognostic factor for RCC patients (hazard ratio 0.056, 95% confidence interval 0.607-1.184; p < 0.001). CONCLUSION: These findings suggest that SOX9 may play an important role in tumor progression of RCC and BCa and it may be used as a biomarker of this malignancy.

Decreased expression of SLC 39A14 is associated with tumor aggressiveness and biochemical recurrence of human prostate cancer.

OBJECTIVE: Solute carrier family 39, member 14 (SLC39A14), has been identified as a potential biomarker for various cancers. However, its roles in prostate cancer (PCa) are still unclear. The aim of this study was to investigate the clinical significance of SLC39A14 in patients with PCa and its functions in malignant phenotypes of PCa cells. PATIENTS AND METHODS: Subcellular localization and expression pattern of SLC39A14 protein were examined by immunohistochemistry. Then, the associations of SLC39A14 expression with various clinicopathological features and clinical outcome of patients with PCa were statistically evaluated. Subsequently, the effects of SLC39A14 overexpression and knockdown on PCa cell proliferation and motility were, respectively, examined by Cell Counting Kit-8, transwell, and wound-healing assays. RESULTS: The immunoreactive scores of SLC39A14 protein in human PCa tissues were significantly lower than those in normal prostate tissues. Based on the Taylor dataset, SLC39A14 downregulation occurred more frequently in patients with PCa with a higher Gleason score (P<0.001), advanced clinical stage (P=0.008), presence of metastasis (P=0.009), and prostate-specific antigen failure (P=0.006). More interestingly, the survival analysis identified SLC39A14 as an independent factor for predicting the biochemical recurrence-free survival of patients with PCa (P=0.017). Functionally, the enforced expression of SLC39A14 could suppress cell proliferation, invasion, and migration of PCa cell lines in vitro, which could be reversed by the knockdown of SLC39A14. CONCLUSION: Decreased expression of SLC39A14 may lead to malignant phenotypes of PCa cells and aggressive tumor progression in patients with PCa. Importantly, SLC39A14 may function as a tumor suppressor and a biomarker for screening patients with biochemical recurrence following radical prostatectomy.

BCL9, a coactivator for Wnt/ß-catenin transcription, is targeted by miR-30c and is associated with prostate cancer progression.

B-cell lymphoma 9 (BCL9), a component of aberrantly activated Wnt signaling, is an important contributing factor to tumor progression. Our previous data indicated that downregulation of the tumor suppressor microRNA-30c (miR-30c) was a frequent pathogenetic event in prostate cancer (PCa). However, a functional link between miR-30c and BCL9/Wnt signaling, and their clinical and pathological significance in PCa, have not been well established. The present study demonstrated that miR-30c serves as a key negative regulator targeting BCL9 transcription in PCa cells. Ectopic expression of miR-30c was associated with reduced expression of Wnt pathway downstream targets, including c-Myc, cluster of differentiation 44 and sex determining region Y-box 9 in DU145 human PCa cells. Examination of clinical prostate specimens revealed higher levels of BCL9 expression in PCa compared with that in benign prostate tissues. After substantiating this finding by patient sample analysis, BCL9 expression or activity was observed to be closely correlated with PCa biochemical recurrence (BCR) and disease progression, whereas it was inversely associated with miR-30c. Furthermore, overexpression of BCL9 in PCa acted cooperatively with miR-30c low expression to predict earlier BCR in PCa. These findings indicate that inhibition of BCL9/Wnt signaling by miR-30c is important in the progression of PCa. Furthermore, the combined analysis of miR-30c and BCL9 may be valuable tool for prediction of BCR in PCa patients following radical prostatectomy.

Association Between Cd Exposure and Risk of Prostate Cancer: A PRISMA-Compliant Systematic Review and Meta-Analysis.

Several observational studies on the association between Cd exposure and risk of prostate cancer have yielded inconsistent results. To address this issue, we conducted a meta-analysis to evaluate the correlation between Cd exposure and risk of prostate cancer.Relevant studies in PubMed and Embase databases were retrieved until October 2015. We compared the highest and lowest meta-analyses to quantitatively evaluate the relationship between Cd exposure and risk of prostate cancer. Summary estimates were obtained using a random-effects model.In the general population, high Cd exposure was not associated with increased prostate cancer (OR 1.21; 95% CI 0.91-1.64), whereas the combined standardized mortality ratio of the association between Cd exposure and risk of prostate cancer was 1.66 (95% CI 1.10-2.50) in populations exposed to occupational Cd. In addition, high D-Cd intake (OR 1.07; 95% CI 0.96-1.20) and U-Cd concentration (OR 0.86; 95% CI 0.48-1.55) among the general population was not related to the increased risk of prostate cancer. In the dose analysis, the summary relative risk was 1.07 (95% CI 0.73-1.57) for each 0.5 µg/g creatinine increase in U-Cd and 1.02 (95% CI 0.99-1.06) for each 10 µg/day increase of dietary Cd intake. However, compared with nonoccupational exposure, high occupational Cd exposure may be associated with the increased risk of prostate cancer.This meta-analysis suggests high Cd exposure as a risk factor for prostate cancer in occupational rather than nonoccupational populations. However, these results should be carefully interpreted because of the significant heterogeneity among studies. Additional large-scale and high-quality prospective studies are needed to confirm the association between Cd exposure and risk of prostate cancer.

E2F1 promotes tumor cell invasion and migration through regulating CD147 in prostate cancer.

Increased expression of E2F1 has been reported to be associated with tumor growth and cell survival of prostate cancer (PCa). However, its roles and mechanisms on PCa have not been fully elucidated. The present study found that E2F1 overexpression in PCa tissues was significantly associated with high Gleason score (P=0.01) and advanced pathological stage (P=0.02). In addition, PCa patients with high E2F1 expression more frequently had shorter biochemical recurrence-free survival (P=0.047) than those with low E2F1 expression. Then, we confirmed that the knock-down of E2F1 expression was able to inhibit cell cycle progression, invasion and migration of PCa cell lines in vitro, along with tumor xenograft growth and epithelial-to-mesenchymal transition (EMT) in vivo. Moreover, we identified CD147 as a novel interaction partner for E2F1 through bio-informatic binding site prediction, combined with chromatin immunoprecipitation-PCR (ChIP-PCR) and western blot analysis. Taken together, our data delineate an as yet unrecognized function of E2F1 as enhancer of tumor invasion and migration of PCa via regulating the expression of CD147 in PCa. Importantly, E2F1 may function as a biomarker that can differentiate patients with biochemical recurrent and non-biochemical recurrent disease following radical prostatectomy, highlighting its potential as a therapeutic target.