The role of microRNAs 371 and 34a in androgen receptor control influencing prostate cancer behavior

BACKGROUND

The molecular mechanisms involved in androgen receptor (AR) signaling pathways are not completely understood, and deregulation of microRNAs (miRNAs) expression may play a role in prostate cancer (PC) development and progression.

METHODS

The expression levels of miRNA and AR were evaluated with quantitative real-time polymerase chain reaction using frozen tissue from the surgical specimens of 83 patients submitted to radical prostatectomy. The expression level of miRNAs was correlated with prognostic factors and biochemical recurrence during a follow-up period of 45 months. In vitro and in vivo experiments were performed to understand the effect of miRNAs over AR in the context of that seen in a PC model.

RESULTS

MiR-371 underexpression correlated with non-organ-confined (pT3) disease (P = 0.009). In vitro transfection of miR-371 reduced the levels of AR by 22% and 28% in LNCaP and PC3 cell lines, respectively, and in kallikrein 3, it was reduced by 51%. PC was induced in Balb/c mice using PC-3M-luc-C6 cells, and animals were treated with 3 local doses of miR-371. Tumor growth evaluated by in vivo imaging after luciferase injection was slower in animals treated with miR-371. To explore further the possible role of miRNAs in the AR pathway, LNCaP cell line was treated with 5α-dihydrotestosterone and flutamide showing alteration in miRNAs expression, especially miR-34a, which was significantly underexpressed after treatment with high doses of 5α-dihydrotestosterone.

CONCLUSION

Our data support a role for miRNAs, especially miR-371 and miR-34a, in the complex disarrangement of AR signaling pathway and in the behavior of PC.

Micro RNA expression and prognosis in low-grade non-invasive urothelial carcinoma

PURPOSE

To analyze a possible correlation between a miRNA expression profile and important prognostic factors for pTa urothelial carcinomas (UC), including tumor size, multiplicity and episodes of recurrence.

MATERIALS AND METHODS

Thirty low-grade non-invasive pTa bladder UC from patients submitted to transurethral resection were studied, in a mean follow-up of 17.7 months. As controls, we used normal bladder tissue from five patients submitted to retropubic prostatectomy to treat benign prostatic hyperplasia. Extraction, cDNA and amplification were performed for 14 miRNAs (miR-100, -10a, -21, -205, -let7c, -143, -145, -221, -223, -15a, -16, -199a and -452) using specific kits, and RNU-43 and -48 were used as endogenous controls. Statistical tests were used to compare tumor size, multiplicity and episodes of recurrence with miRNAs expression profiles.

RESULTS

There was a marginal correlation between multiplicity and miR-let7c over-expression. For all others miRNA no correlation between their expression and prognostic factors was found.

CONCLUSION

We did not find differences for miRNAs expression profiles associated with prognostic factors in tumor group studied. The majority of miRNAs are down-regulated, except mir-10a, over-expressed in most of cases, seeming to have increased levels as tumor with more unfavorable prognostic factors. More studies are needed in order to find a miRNA profile able to provide prognosis in pTa UC to be used in clinical practice.

Controlling RECK miR21 Promotes Tumor Cell Invasion and Is Related to Biochemical Recurrence in Prostate Cancer

The search for biomarkers to characterize prostate cancer aggressiveness has been the objective for the majority of researchers involved with the most prevalent tumor in men. MiRNAs are important for the control of many cellular functions and their deregulation is involved with tumor development and progression. To find miRNAs differentially expressed in prostate cancer and their relation to prognostic factors and biochemical recurrence we studied 53 surgical specimens from men who underwent radical prostatectomy, through a microarray analysis using the microarray platform (GeneChip® miRNA Array - Affymetrix) with more than 46,000 probes and 847 mature human miRNAs and transcripts. We defined different as an expression level greater or less than 1.1 with p<0.05. The validation study using qRT-PCR had confirmed miR21 as overexpressed in tumor that have recurred with a risk of 2.5. Transfection of miR-21 using lipid based assay in DU145 cell line, showed decrease in expression of RECK resulting in increase in expression of MMP9. Invasion assay with Matrigel showed increase in tumor cell invasion after miR-21 transfection. We conclude that miR-21 overexpression is related to increased biochemical recurrence after surgical treatment of prostate cancer. And the negative control of RECK results in overexpression of MMP9 promotes increasing tumor cell invasion supporting miR-21 as an oncomiR related to aggressiveness in prostate cancer.

MiRNA in bladder carcinogenesis: A review

Bladder cancer (BC) is the second urological malignancy in incidence, currently being one of the most neoplasms studied with profile and biology poorly defined. In the world, BC is responsible by about 386000 new cases and 150000 deaths annually with considerable economic impact and high costs for health systems. After its discovery more than 20 years, micro RNAs (miRNAs) have been recognized as molecules that work specifically in post-transcriptional control in majority of eukaryote genomes. MiRNAs are a family of small non-coding RNAs of 19-25 nucleotides in length, expressed in a wide variety of organisms, comprising plants, worms and mammals, including humans. They have a fundamental role in physiological and pathological processes in organs and tissues in a context-dependent manner. This review brings new roles of protective and oncogenic miRNAs linked to carcinogenesis of urothelial carcinoma of the bladder, and associated with behavior of disease. Many studies have demonstrated promising roles of miRNAs working as diagnostic and prognostic biomarkers or involved in target therapies, consolidating miRNAs as crucial players in human cancer. This review allowed a reflection about the true functions of miRNAs in bladder carcinogenesis. Not only by their wide capacities of action, but also by abilities in define the cell date. The future of anti-tumor target therapies will be based not in one, but in groups of miRNAs working together in several steps of carcinogenic process, being able to identify the disease, predicting behavior and effectively treat bladder cancer.

Comprehensive study of gene and microRNA expression related to epithelial-mesenchymal transition in prostate cancer

Prostate cancer is the most common cancer in men, and most patients have localized disease at the time of diagnosis. However, 4% already present with metastatic disease. Epithelial-mesenchymal transition is a fundamental process in carcinogenesis that has been shown to be involved in prostate cancer progression. The main event in epithelial-mesenchymal transition is the repression of E-cadherin by transcription factors, but the process is also regulated by microRNAs. The aim of this study was to analyze gene and microRNA expression involved in epithelial-mesenchymal transition in localized prostate cancer and metastatic prostate cancer cell lines and correlate with clinicopathological findings. We studied 51 fresh frozen tissue samples from patients with localized prostate cancer (PCa) treated by radical prostatectomy and three metastatic prostate cancer cell lines (LNCaP, DU145, PC3). The expression of 10 genes and 18 miRNAs were assessed by real-time PCR. The patients were divided into groups according to Gleason score, pathological stage, preoperative PSA, biochemical recurrence, and risk group for correlation with clinicopathological findings. The majority of localized PCa cases showed an epithelial phenotype, with overexpression of E-cadherin and underexpression of the mesenchymal markers. MiRNA-200 family members and miRNAs 203, 205, 183, 373, and 21 were overexpressed, while miRNAs 9, 495, 29b, and 1 were underexpressed. Low-expression levels of miRNAs 200b, 30a, and 1 were significantly associated with pathological stage. Lower expression of miR-200b was also associated with a Gleason score ≥ 8 and shorter biochemical recurrence-free survival. Furthermore, low-expression levels of miR-30a and high-expression levels of Vimentin and Twist1 were observed in the high-risk group. Compared with the primary tumor, the metastatic cell lines showed significantly higher expression levels of miR-183 and Twist1. In summary, miRNAs 200b, 30a, 1, and 183 and the genes Twist1 and Vimentin might play important roles in the progression of prostate cancer and may eventually become important prognostic markers.

Stage, grade and behavior of bladder urothelial carcinoma defined by the microRNA expression profile

PURPOSE

We identified miRNA expression profiles in urothelial carcinoma that are associated with grade, stage, and recurrence-free and disease specific survival.

MATERIALS AND METHODS

The expression of 14 miRNAs was evaluated by quantitative reverse transcriptase-polymerase chain reaction in surgical specimens from 30 patients with low grade, noninvasive (pTa) and 30 with high grade, invasive (pT2-3) urothelial carcinoma. Controls were normal bladder tissue from 5 patients who underwent surgical treatment for benign prostatic hyperplasia. Endogenous controls were RNU-43 and RNU-48. miRNA profiles were compared and Kaplan-Meier curves were constructed to analyze disease-free and disease specific survival.

RESULTS

miR-100 was under expressed in 100% of low grade pTa specimens (p <0.001) and miR-10a was over expressed in 73.3% (p <0.001). miR-21 and miR-205 were over expressed in high grade pT2-3 disease (p = 0.02 and <0.001, respectively). The other miRNAs were present at levels similar to those of normal bladder tissue or under expressed in each tumor group. miR-21 over expression (greater than 1.08) was related to shorter disease-free survival in patients with low grade pTa urothelial carcinoma. Higher miR-10a levels (greater than 2.30) were associated with shorter disease-free and disease specific survival in patients with high grade pT2-3 urothelial carcinoma.

CONCLUSIONS

Four miRNAs were differentially expressed in the 2 urothelial carcinoma groups. miR-100 and miR-10a showed under expression and over expression, respectively, in low grade pTa tumors. miR-21 and miR-205 were over expressed in pT2-3 disease. In addition, miR-10a and miR-21 over expression was associated with shorter disease-free and disease specific survival. miRNAs could be incorporated into the urothelial carcinoma molecular pathway. These miRNAs could also serve as new diagnostic or prognostic markers and new target drugs.

[A seroepidemiological survey on the island of São Luis during a dengue epidemic in Maranhão]

The island of São Luis in the State of Maranhão, constituted by the municipalities of São Luis-SL (835,428 inhabitants), São José de Ribamar-SJR (60,633 inhabitants) and Paço do Lumiar-PL (80,274 inhabitants), has been suffering dengue (DEN) fever epidemics since 1995, caused by DEN-1. In 1996, from August through October, an aleatory sero-epidemiologic survey was carried out in order to estimate the incidence of DEN infection and to analyze other clinical and epidemiological parameters. A questionnaire was applied and serum samples were simultaneously obtained. Serum samples were tested by hemagglutination inhibition (HI). Results were analyzed using Lotus 123, Epi-info 6.0, Excel 5.0 and STATA softwares. A total of 1,217 serum samples were obtained (101 of PL, 100 of SJR and 1017 of SL). The rate of DEN was 55.4% in PL, 28% in SJR and 41.4% in SL, suggesting the occurrence of 401,933 infections. No difference was seen between males and females, but infection occurred more in the upper social class than in poor people (p < 0.003), and was more frequent in adults than in children (p < 0.0004). In SL, the incidence was stratified into seven sanitary districts (SD), and prevalence was found to range from 26.1% in SD4 to 56.8% in SD1 (p < 0.0001). Symptoms were more frequently reported by people whose HI was positive: they included fever, headache, chills, dizziness, retrobulbar pains, muscle and joint pains, nausea, anorexia and skin rash. In spite of the high incidence of infection, no hemorrhagic cases were reported.