FOXM1-Dependent Transcriptional Regulation of EZH2 Induces Proliferation and Progression in Prostate Cancer.

BACKGROUND: Prostate cancer is one of the most commonly diagnosed cancers and one of the most common causes of cancer-related deaths among men worldwide. Patients who are diagnosed with localized prostate cancer and treated with radical prostatectomy often respond well to therapy. The current standard therapy for prostate cancer involves maximal surgical resection, followed by radiotherapy and chemotherapy. Clarifying the molecular mechanism of tumor proliferation and recurrence becomes more and more important for clinical therapies of prostate cancer. METHODS: Quantitative Real-Time PCR and Western-blot were used in the detection of mRNA and protein expression. Lentivirus infection was used to overexpress or knockdown the target gene. Flow cytometry analysis was performed to test protein expression and apoptosis level. Immunohistochemistry was used to identify protein expression in tissue. Statistical differences between the two groups are evaluated by two-tailed t-tests. The comparison among multiple groups is performed by one-way Analysis of Variance (ANOVA) followed by Dunnett's posttest. The statistical significance of the Kaplan-Meier survival plot is determined by log-rank analysis. RESULTS: In this study, we identified that FOXM1 expression was significantly enriched in prostate cancer compared with normal tissue. Additionally, FOXM1 was functionally required for tumor proliferation and its expression was associated with poor prognosis in prostate cancer patients. Mechanically, FOXM1-dependent regulation of EZH2 is essential for proliferation and progression in prostate cancer. CONCLUSION: Taken together, our data suggest that oncogenic transcription factor FoxM1 is up-regulated in prostate cancer, suggesting that the growth of cancer cells may depend on FOXM1 activity. FOXM1 may serve as a clinical prognostic factor and a therapeutic target for prostate cancer.

BUB1B Promotes Proliferation of Prostate Cancer via Transcriptional Regulation of MELK.

BACKGROUND: Prostate cancer remains one of the most common and deadliest forms of cancer, generally respond well to radical prostatectomy and associated interventions, up to 30% of individuals will suffer disease relapse. Although BUB1B was found to be essential for cell growth and proliferation, even in several kinds of tumor cells, the specific importance and mechanistic role of BUB1B in prostate cancer remain unclear. METHODS: Quantitative Real-Time PCR and Western-blot were used in the detection of mRNA and protein expression. Lentivirus infection was used to overexpression or knock down the target gene. Flow cytometry analysis was performed to test protein expression and apoptosis level. Immunohistochemistry was used to identify protein expression in tissue. Statistical differences between the two groups are evaluated by two-tailed t-tests. The comparison among multiple groups is performed by one-way Analysis of Variance (ANOVA) followed by Dunnett's posttest. The statistical significance of the Kaplan-Meier survival plot is determined by log-rank analysis. RESULTS: In the present report, we found BUB1B expression to be highly increased in prostate cancer tissues relative to normal controls. We further found BUB1B to be essential for efficient tumor cell proliferation, and to correlate with poorer prostate cancer patient outcomes. From a mechanistic perspective, the ability of BUB1B to regulate MELK was found to be essential for its ability to promote prostate cancer cell proliferation. CONCLUSION: Altogether, our data suggest that BUB1B is up-regulated in prostate cancer, suggesting that the growth of cancer cells may depend on BUB1B-dependent regulation of MELK transcription. BUB1B may serve as a clinical prognostic factor and a druggable target for prostate cancer.

A common genetic variation in CEBPE and acute lymphoblastic leukemia: a meta-analysis of the available evidence.

Acute lymphoblastic leukemia (ALL) has been studied intensively for decades, but the details of its etiology and underlying mechanisms have yet to be fully elucidated. It is now generally acknowledged that genetic factors contribute greatly to the development of this disease. The gene encoding CCAAT/enhancer-binding protein ε (CEBPE) is involved in the development of leukemia, and in particular the rs2239633 single nucleotide polymorphism (SNP) of CEBPE. The association between rs2239633 and risk of ALL has been well studied, but remains unclear. Therefore, a meta-analysis was performed in this study to establish a more precise estimation of that relationship. A comprehensive literature search of the PubMed electronic database was conducted, and relevant studies published up to February 20, 2015 were selected for analysis. The references of the retrieved articles were also screened. The extracted data were analyzed statistically, and pooled odds ratios with 95% confidence intervals were calculated using Review Manager (version 5.2) to estimate the association strength. Finally, eleven studies were included in the meta-analysis. The pooled analyses revealed that rs2239633 was associated with an increased risk of childhood ALL in Caucasians under any contrast models (P<0.01). However, this SNP did not affect the risk of ALL in adulthood among Caucasians, or in childhood among East Asians. In conclusion, these findings confirm that the CEBPE rs2239633 SNP could be considered a good marker of pediatric ALL risk in Caucasians, but not in East Asians; it is not a good marker of adult ALL risk in Caucasians.

miR-124 represses FZD5 to attenuate P-glycoprotein-mediated chemo-resistance in renal cell carcinoma.

Renal cell carcinoma (RCC) is one of most malignant neoplasms, exhibiting poor responsiveness to the conventional chemo-regime. Abnormal expression of P-glycoprotein (P-gp) has been implicated in the emergence of multiple-drug resistance (MDR) by reducing the accumulation of intracellular chemotherapy drugs. Wnt signaling plays critical roles in renal cancer and is triggered by binding of Wnt ligands to Frizzled (FZD) receptor proteins. miR-124 is a tumor suppressor associated with cancer relapse and MDR, whereas its role in P-gp-mediated MDR in refractory RCC is as yet unrevealed. Our study aimed to investigate the roles of miR-124 in chemo-resistant RCC cells and the potential targeted signaling paths in inducing P-gp expression. Doxorubicin (DOX)- and vinblastine (VBL)-resistant Caki-2 cells were developed by exposure of parental Caki-2 cells to the agents over a long period of time. In comparison with their parental cells, miR-124 was downregulated in Caki-2/DOX and Caki-2/VBL cells, accompanied by increased FZD5 and P-gp. IC50 values were reduced significantly after miR-124 mimics were introduced into Caki-2/DOX cells. In addition, miR-124 mimics significantly promoted apoptosis of Caki-2/DOX cells. miR-124 targeted to FZD5 and miR-124 mimics as well as FZD5 siRNA showed significant inhibitory effects on P-gp expression in Caki-2/DOX cells. Furthermore, Wnt-5a dose-dependently stimulated the presentation of p-PKCα/ßII and p-CamKII via activating FZD5, which was reversed by FZD5 silencing. Moreover, FZD5/protein kinase C (PKC) signaling is responsible for the elevation of P-gp and cancer cell survival. In conclusion, restoring miR-124 may function as a promising strategy to overcome P-gp-mediated MDR by inhibiting FZD5/PKC signaling.

Downregulation of mTOR by lentivirus inhibits prostate cancer cell growth.

Prostate cancer, one of the most lethal forms of urinary system cancer, remains resistant to currently available treatments. Therefore, novel mechanism and target-based approaches are needed for the management of this neoplasm. PI3K/AKT signaling pathway activation correlates with human prostate cancer progression and metastasis. However, the role of mTOR in prostate cancer is not well-established. Here, we demonstrate that mTOR is over-expressed in both clinical tissue specimens and cultured human prostate cancer cells when compared to normal prostate tissues, respectively. Further, mTOR gene knockdown via lentivirus mediated mTOR specific shRNA resulted in a significant decrease in the viability and growth of prostate cancer cells without affecting normal human prostate cells. In addition, mTOR inhibition resulted in a significant i) decrease in 4EBP1, S6K, PI3K and AKT protein, ii) increase in PARP protein of prostate cancer cells. Most importantly, mTOR inhibition triggered apoptosis and suppressed pancreatic carcinoma growth in vivo in a mouse xenograft model. We suggest that targeting of mTOR may be a viable approach for the treatment of prostate cancer.

Interaction of CCN1 with αvß3 integrin induces P-glycoprotein and confers vinblastine resistance in renal cell carcinoma cells.

Renal cell carcinoma (RCC) ranks among the most chemoresistant tumors, and P-glycoprotein (P-gp) predominates multidrug resistance mechanisms by reducing the accumulation of intracellular chemotherapy drugs such as vinblastine (VBL), which is considered the most effective chemotherapeutic agent for this neoplasia. Unfortunately, the mechanism by which the expression of P-gp is regulated and the ways to inhibit the function of P-gp are poorly understood. Our study was carried out to determine the possible role of CCN1 in P-pg-mediated drug resistance on the basis of the validated function of CCN1, an extracellular matrix protein, in promoting chemoresistance. As expected, CCN1 was overexpressed in VBL-resistant cell lines (ACHN/VBL, A498/VBL, Caki-1/VBL, and Caki-2/VBL) as measured by enzyme-linked immunosorbent assay. We then transfected non-VBL-resistant cell lines with Ad-CCN1 and observed that the IC50 of VBL increased by about 3-5 times. Furthermore, both CCN1 antibody neutralization and αvß3 integrin antibody blockade decreased the IC50 of VBL, which showed that CCN1 and αvß3 are associated with resistance to VBL in RCC. Simultaneously, the enhanced expression of CCN1 triggered the intracellular PI3K/Akt pathway by binding αvß3 integrin, as shown by western blot. P-gp expression was augmented in response to activation of the PI3K/Akt pathway, which could be modified by PI3K inhibitor LY294002 or multidrug resistance siRNA transfection. Therefore, targeted restraint of CCN1 or αvß3 integrin in combination with the administration of VBL may be beneficial in the treatment of primary and metastatic RCC.

Prostate-targeted mTOR-shRNA inhibit prostate cancer cell growth in human tumor xenografts.

OBJECTIVE: To construct a recombinant lentivirus vector driven by the PSMA promoter carrying mTOR-shRNA, and to obtain the effect on the mTOR gene silencing in human prostate cancer xenografts. METHODS: The complimentary oligos of small interference RNA (siRNA) with hairpin structures targeting the mTOR gene and a negative control were synthesized, then ligated with pLV-PSMA-promoter vector and sequenced. The recombinant vectors were then transfected with viral packaging mix into 293T cells, viral supernatant was harvested to determine the titer. Prostate cancer cells infected by virus were harvested and the expression of mTOR (LV-PSMA-shmTOR), target proteins and cell growth were detected by reverse transcription-PCR (RT-PCR), Western blot and MTT separately. In established tumors derived from human prostate cancer cells, concentrated LV-PSMA-shmTOR lentivirus was injected intravenously in the tail vein of C4-2b tumor bearing female severe combined immunodeficient (SCID) mice. Tumor volume and immunohistochemistry was assessed. RESULTS: Sequencing data showed that the constructed plasmids contained the correct sequences of mTOR siRNA transcript templates. A vector producing cell line 293T was established, and the titer for transfection was obtained. RT-PCR, Western blot and MTT analyses demonstrated that mTOR shRNA expression construct could suppress the expression of mTOR and inhibit the prostate cancer cell growth, specially. The tumor growth was suppressed in nude mouse. CONCLUSION: A PSMA driven lentivirus mediated siRNA targeting mTOR gene was successfully constructed, which decreased the expression of mTOR and induced the prostate cancer cell growth in vitro and in vivo. It has set up a research platform for the gene therapy of tumors which take mTOR as the target in the prostate cancer field.

Replication and fine mapping for association of the C2orf43, FOXP4, GPRC6A and RFX6 genes with prostate cancer in the Chinese population.

BACKGROUND: Prostate cancer represents the leading cause of male death across the world. A recent genome-wide association study (GWAS) identified five novel susceptibility loci for prostate cancer in the Japanese population. This study is to replicate and fine map the potential association of these five loci with prostate cancer in the Chinese Han population. METHODS: In Phase I of the study, we tested the five single nucleotide polymorphisms (SNPs) which showed the strongest association evidence in the original GWAS in Japanese. The study sample consists of 1,169 Chinese Hans, comprising 483 patients and 686 healthy controls. Then in phase II, flanking SNPs of the successfully replicated SNPs in Phase I were genotyped and tested for association with prostate cancer to fine map those significant association signals. RESULTS: We successfully replicated the association of rs13385191 (located in the C2orf43 gene, P = 8.60×10(-5)), rs12653946 (P = 1.33×10(-6)), rs1983891 (FOXP4, P = 6.22×10(-5)), and rs339331 (GPRC6A/RFX6, P = 1.42×10(-5)) with prostate cancer. The most significant odds ratio (OR) was recorded as 1.41 (95% confidence interval 1.18-1.68) for rs12653946. Rs9600079 did not show significant association (P = 8.07×10(-2)) with prostate cancer in this study. The Phase II study refined these association signals, and identified several SNPs showing more significant association with prostate cancer than the very SNPs tested in Phase I. CONCLUSIONS: Our results provide further support for association of the C2orf43, FOXP4, GPRC6A and RFX6 genes with prostate cancer in Eastern Asian populations. This study also characterized the novel loci reported in the original GWAS with more details. Further work is still required to determine the functional variations and finally clarify the underlying biological mechanisms.

Multi-target siRNA based on DNMT3A/B homologous conserved region influences cell cycle and apoptosis of human prostate cancer cell line TSU-PR1.

Abnormal genome hypermethylation participates in the tumorigenesis and development of prostate cancer. Prostate cancer cells highly express DNA methyltransferase 3 (DMNT3) family genes, essential for maintaining genome methylation. In the present study, multi-target siRNA, based on the homologous region of the DNMT3 family, was designed for the in vitro investigation of its effects on the proliferation, migration, and invasion of TSU-PR1 prostate cancer cells. The consequential cell-cycle derangement, through DNMT3A/B or only DNMT3B silencing, was partially efficient, without affecting apoptosis. DNMT3A silencing had absolutely no effect on changing TSU-PR1 cell biological behavior. Hence, DNMT3B alone apparently plays a key role in maintaining the unfavorable behavior of prostate-cancer cells, thereby implying its potential significance as a promising therapeutic target, with DNMT3A simply in the role of helper.

Holmium laser enucleation of the prostate: a modified enucleation technique and initial results.

PURPOSE: Although holmium laser enucleation of the prostate has been proven to be an excellent technique for the treatment of benign prostatic hyperplasia, it has not been widely applied due to technical difficulties and longer operative time. We modified the current technique of enucleation and present our initial experience. MATERIALS AND METHODS: A total of 189 patients with benign prostatic hyperplasia underwent prostatectomy with our modified technique for holmium laser enucleation of the prostate. Intraoperative and postoperative data were prospectively collected. For followup International Prostate Symptom Score, quality of life, maximal flow rate and post-void residual urine were recorded. RESULTS: Mean±SD preoperative prostate volume was 78.1±24.3 cc and 60.9±39.2 gm tissue were enucleated. Mean operative and enucleation times were 54.7±21.1 and 36.5±16.3 minutes, respectively. Mean serum hemoglobin decrease was 0.98±0.72 gm/dl. Mean catheter time was 1.2±0.5 days and mean postoperative hospital stay was 4.9±3.4 days. Serious complications were not observed. Three patients complained of transient stress incontinence which resolved within 3 months. Significant improvement occurred in International Prostate Symptom Score, quality of life, maximal flow rate and post-void residual urine volume at 3 and 6-month followup compared with the preoperative baseline. CONCLUSIONS: The modified holmium laser enucleation of the prostate technique is effective and safe when treating benign prostatic hyperplasia.

Multi-target siRNA based on DNMT3A/B homologous conserved region influences cell cycle and apoptosis of human prostate cancer cell line TSU-PR1

Abnormal genome hypermethylation participates in the tumorigenesis and development of prostate cancer. Prostate cancer cells highly express DNA methyltransferase 3 (DMNT3) family genes, essential for maintaining genome methylation. In the present study, multi-target siRNA, based on the homologous region of the DNMT3 family, was designed for the in vitro investigation of its effects on the proliferation, migration, and invasion of TSU-PR1 prostate cancer cells. The consequential cell-cycle derangement, through DNMT3A/B or only DNMT3B silencing, was partially efficient, without affecting apoptosis. DNMT3A silencing had absolutely no effect on changing TSU-PR1 cell biological behavior. Hence, DNMT3B alone apparently plays a key role in maintaining the unfavorable behavior of prostate-cancer cells, thereby implying its potential significance as a promising therapeutic target, with DNMT3A simply in the role of helper.

Establishment of CXCR4-small interfering RNA retrovirus vector driven by human prostate-specific antigen promoter and its biological effects on prostate cancer in vitro and in vivo.

PURPOSE: CXC chemokine receptor-4 (CXCR4) is closely involved in bone metastasis of prostate cancer, and CXCR4 levels are frequently increased in prostate cancer cells and tissues. In the present study, its biological effects on prostate cancer in vitro and in vivo and feasibility to be a therapy target were investigated using a RNA interfering retrovirus vector targeting CXCR4 gene driven by human prostate-specific antigen promoter (pPSA). METHODS: We established a pPSA-siCXCR4 retrovirus vector and transfected prostate cancer cell PC-3m, LNCaP and breast cancer cell MCF-7, respectively. The expression of CXCR4 mRNA and protein was detected by RT-PCR and western blot, and the ability of adhesion, migration, invasion of prostate cancer cells was assessed using Transwell chamber. A metastasizing model using BALB/cA mice with human bone tissue implantation was established too, and transfected prostate cancer cells were via caudal vein. Survival time of mice suffering bone metastatic tumor as well as the weight and volume of these tumors were recorded and analyzed. RESULTS: The expression of CXCR4 mRNA and protein in androgen-responsive LNCaP cells was blocked by the pPSA-siCXCR4 vector, but it could not work in non androgen-responsive PC-3m cell and breast cancer cell MCF-7. The results of experiments in vitro also showed that the adhesion, transendothelial migration and invasive ability of transfected LNCaP cells were impaired, while there was no change in PC-3m and MCF-7 cells after transfection. pPSA-siCXCR4 represented a similar inhibitory effect in fluorescent bone metastasis model of LNCaP cells compared with PC-3m cells. CONCLUSION: These results suggest that the downstream siRNA controlled by PSA promoter in retrovirus system can express selectively in androgen-responsive prostate cancer in vitro and in vivo, and CXCR4 plays an important role in prostate cancer metastasis. We believe that the pPSA-siCXCR4 retrovirus vector is a potential choice in gene therapy for androgen-responsive prostate cancer.

[Establishment of RNA interfering retrovirus vector targeting CXCR4 gene driven by human prostate-specific antigen promoter and its biological effects on prostate cancer cells].

OBJECTIVE: To construct RNA interfering retrovirus vector targeting CXCR4 gene driven by human prostate-specific antigen promoter and investigate its targeted inhibition effects in androgen-responsive prostate cancer cells LNCaP. METHODS: To clone the CXCR4 targeting siRNA gene by PCR. The PCR products were inserted into the pGensil-1 plasmid containing U6 promoter and EGFP. U6 promoter was replaced by hPSA promoter. Then, the recombinant EGFP-hPSA-siCXCR4 fragment was sub-cloned into pLXSN, which was evaluated by restriction enzyme. The pLXSN-EGFP-hPSA-siCXCR4 was transfected into PA317 cells with Lipofectamine 2000. The virus obtained from transfected PA317 cells was transfected into PC-3m, LNCaP and MCF-7 cells, respectively. The expression of CXCR4 mRNA and protein was detected by RT-PCR and Western blot. The invasion ability of prostate carcinoma cells was detected by Transwell experiment. RESULTS: The recombinant pLXSN-hPSA-siCXCR4 was successfully constructed. The expression of CXCR4 mRNA and protein in LNCaP cells was blocked by pLXSN-hPSA-siCXCR4. The expression inhibition rate was (81.53 +/- 10.22)% at mRNA level detected by semi-quantitive RT-PCR and (90.52 +/- 9.31)% at protein level detected by Western blot, respectively, in LNCaP cells at 48 h. The expression of CXCR4 mRNA and protein was effectively inhibited by sequence-specific hPSA-siCXCR4 in LNCaP cells, but not in PC-3m and MCF-7 cells. The results of Transwell experiment showed that the number of cells in down-pore of micro-membrane was 139.9 +/- 14. 2 in the treated group, significantly less in comparison with 348.4 +/- 36. 4 in the controlled group (P < 0.05). However, the number of PC-3m and MCF-7 cells in down-pore of micro-membrane was not significantly different among the control and treated groups (P > 0.05). CONCLUSION: The downstream siRNA controlled by hPSA promoter in retrovirus system can be expressed selectively in androgen-responsive prostate carcinoma cells, showing an apparent targeting character. RNAi targeted to CXCR4 driven by hPSA promoter has a potential value in gene therapy of androgen-responsive prostate cancer.