MicroRNA-141 is downregulated in human renal cell carcinoma and regulates cell survival by targeting CDC25B.

UNLABELLED: BACKGROUNDOBJECTIVE: MicroRNAs (miRNAs) are small noncoding RNAs (ribonucleic acids), approximately 22 nucleotides in length, that function as regulators of gene expression. Dysregulation of miRNAs has been associated with the initiation and progression of oncogenesis in humans. The cell division cycle (CDC)25 phosphatases are important regulators of the cell cycle. Their abnormal expression detected in a number of tumors implies that their dysregulation is involved in malignant transformation. METHODS: Using miRNA target prediction software, we found that miR-141 could target the 3' untranslated region (3'UTR) sequence of CDC25B. To shed light on the role of miR-141 in renal cell carcinogenesis, the expression of miR-141 was examined by real-time polymerase chain reaction (RT-PCR) in renal cell carcinoma and normal tissues. The impact of miR-141 re-expression on 769-P cells was analyzed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assay. A luciferase reporter assay was applied to prove the functionality of the miR-141 binding site. RESULTS: miR-141 is significantly downregulated in renal cell carcinoma. miR-141 re-expression suppressed cell growth in 769-P cells. Luciferase expression from a reporter vector containing the CDC25B-3'UTR was decreased when this construct was transfected with miR-141 in 769-P cells. The overexpression of miR-141 suppressed the endogenous CDC25B protein level in 769-P cells. CONCLUSION: For the first time, we demonstrated that CDC25B is a direct target of miR-141 in renal cell carcinoma. The transcriptional loss of miR-141 and the resultant increase in CDC25B expression facilitates increased genomic instability at an early stage of renal cell carcinoma development.

Knockdown of Cdc25B in renal cell carcinoma is associated with decreased malignant features.

Cdc25 phosphatases are important regulators of the cell cycle. Their abnormal expression detected in a number of tumors implies that their dysregulation is involved in malignant transformation. However, the role of Cdc25B in renal cell carcinomas remains unknown. To shed light on influence on renal cell carcinogenesis and subsequent progression, Cdc25B expression was examined by real-time RT-PCR and western blotting in renal cell carcinoma and normal tissues. 65 kDa Cdc25B expression was higher in carcinomas than in the adjacent normal tissues (P<0.05), positive correlations being noted with clinical stage and histopathologic grade (P<0.05). To additionally investigate the role of Cdc25B alteration in the development of renal cell carcinoma, Cdc25B siRNA was used to knockdown the expression of Cdc25B. Down-regulation resulted in slower growth, more G2/M cells, weaker capacity for migration and invasion, and induction of apoptosis in 769-P transfectants. Reduction of 14-3-3 protein expression appeared related to Cdc25B knockdown. These findings suggest an important role of Cdc25B in renal cell carcinoma development and provide a rationale for investigation of Cdc2B-based gene therapy.

Low microsomal epoxide hydrolase expression is associated with bladder carcinogenesis and recurrence.

Microsomal epoxide hydrolase (mEH) plays a significant role in the metabolism of numerous xenobiotics and is associated with several forms of cancer. Here, we investigated the role of mEH expression in bladder carcinogenesis, subsequent progression and recurrence. The expression of mEH was analyzed by Western blot in 50 bladder urothelial carcinoma and 20 normal epithelial tissues. There was a significantly higher mEH expression in the normal epithelium (P<0.05) and mEH expression was lower in high stage than in low stage tumors (P<0.05). Further, immunohistochmistry in 106 bladder urothelial carcinoma demonstrated mEH expression to be negatively correlated with histological grade, pT stage and recurrence (P<0.05). These findings suggest the important role of mEH in bladder carcinogenesis, cancer development and recurrence, providing support for efforts to develop mEH-based gene therapy.

Overexpression of RIN1 associates with tumor grade and progression in patients of bladder urothelial carcinoma.

Ras and Rab interactor 1 (RIN1) is an effector of H-Ras, which plays an important role in the development and progression of carcinomas, but it has not been reported in bladder cancer. Hence, the association of RIN1 expression with prognosis of bladder urothelial carcinoma (UC) was examined. RIN1 mRNA and protein expression in 20 paired UCs and the adjacent normal tissues was detected by quantitative reverse transcription polymerase chain reaction and Western blot. The expression of RIN1 protein in 96 specimens of UCs and 22 specimens of adjacent normal bladder tissues were analyzed by immunohistochemistry. The overall survival (OS) was assessed by univariate and multivariate analysis. Moreover, the progression-free survival (PFS) and recurrence-free survival (RFS), classified by the clinicopathologic features with RIN1 expression, were assessed by multivariate analysis. RIN1 mRNA and protein level was higher in UCs than in the adjacent normal tissues (P < 0.01). Enhanced RIN1 immunoexpression was associated with high histologic grades (P = 0.046), cancer progression (P = 0.047) as well as Ki-67 expression (P = 0.023). Furthermore, the 5-year survival rate was 29% in the subgroup with high level of RIN1 expression, while it was 43% in the subgroup with normal level of RIN1 expression (P < 0.05). Importantly, RIN1 level was revealed as the significant independent prognostic factor for death (P = 0.023) and progression (P = 0.003), but a weak contribution for recurrence (P = 0.063). Collectively, RIN1 expression could be a potential prognostic predictor for UC patients.

The role of zinc transporter ZIP4 in prostate carcinoma.

OBJECTIVE: Normal prostate tissues have a unique function of accumulating high levels of zinc. This capability is lost during the early stage in the development of prostate malignancy. ZIP4 is an important zinc transporter. In this study, we explore the expression of ZIP4 in prostate carcinoma and invest the functional contributions of ZIP4 to cancer growth in vitro. METHODS: ZIP4 expression was detected in 14 prostate carcinoma and 20 BPH tissues by real-time RT-PCR and western blot. To invest the biological function of ZIP4 in prostate carcinoma cells, ZIP4 stable over-expression in cells was established in prostate carcinoma cell line DU145 (DU145-ZIP4) and ZIP4 short hairpin RNA(shRNA) expression in stable cells was also established in prostate carcinoma cell line 22RV1(22RV1-shRNA). The proliferation, migration, and invasion ability of the prostate carcinoma cells were detected. RESULTS: The expression of ZIP4 mRNA and protein are significantly down-regulated in prostate carcinoma tissues compared with that in BPH tissues. However, we found that there was no correlation between the ZIP4 expression and the pathologic grade of prostate carcinoma. In in vitro studies, over-expression of ZIP4 not only inhibits the proliferation but also inhibits the invasive ability of prostate carcinoma cell line DU145-ZIP4. At the same time, we found silencing of ZIP4 was associated with increased cell proliferation and invasion ability in 22RV1-shRNA cell line. However, both DU145-ZIP4 and 22RV1-shRNA cells showed a significant reduction on cell migration ability compared with the control. CONCLUSION: The results indicate that ZIP4 expression is down-regulated in prostate carcinoma and it may serve as a promising biomarker for prostate carcinoma. ZIP4 has an inhibitory effect on prostate carcinoma cell proliferation and invasion. It suggests that ZIP4 may be a tumor suppressor gene and down-regulation of ZIP4 may be a critical early event in the development of prostate carcinoma.

[Study on multiple aldosterone-producing adenomas].

OBJECTIVE: To investigate the experience on diagnosis and treatment of multiple adrenal aldosterone-producing adenomas (APA). METHODS: Eighteen cases of multiple adrenal APA were analyzed retrospectively, which were admitted from October 1992 to April 2006. RESULTS: Adrenalectomy was performed for 4 cases of unilateral synchronous multiple APA, which were discovered with three adenomas by 3D-CT; bilateral tumor resection was performed for 6 cases of bilateral synchronous multiple APA. There were 8 cases of bilateral metachronous multiple APA, including 2 cases of ipsilateral recurrent adrenal APA after adrenal tumor removal, which underwent tumor resection. Another 6 cases were contralateral APA following adrenalectomy due to adrenal APA, and underwent tumor resection. After operation, the adrenal function seemed to be normal, and no recurrence had been found on follow-up. CONCLUSIONS: Unilateral multiple synchronous APA require adrenalectomy. Tumor resection should be performed for bilateral or asynchronous APA, and it is very important to preserve healthy adrenal tissue as much as possible. 3D-CT has much value on diagnosis of small APA, unilateral multiple synchronous APA and ipsilateral recurrent adrenal APA.