Reversing epithelial-to-mesenchymal transition (EMT) in cancer cells has been widely considered as an approach to combat cancer progression and therapeutic resistance, but a limited number of broadly comprehensive investigations of miRNAs involved in this process have been conducted. In this study, we screened a library of 1120 miRNA for their ability to transcriptionally activate the E-cadherin gene CDH1 in a promoter reporter assay as a measure of EMT reversal. By this approach, we defined miR-520f as a novel EMT-reversing miRNA. miR-520f expression was sufficient to restore endogenous levels of E-cadherin in cancer cell lines exhibiting strong or intermediate mesenchymal phenotypes. In parallel, miR-520f inhibited invasive behavior in multiple cancer cell systems and reduced metastasis in an experimental mouse model of lung metastasis. Mechanistically, miR-520f inhibited tumor cell invasion by directly targeting ADAM9, the TGFβ receptor TGFBR2 and the EMT inducers ZEB1, ZEB2, and the snail transcriptional repressor SNAI2, each crucial factors in mediating EMT. Collectively, our results show that miR-520f exerts anti-invasive and antimetastatic effects in vitro and in vivo, warranting further study in clinical settings. Cancer Res; 77(8); 2008–17. ©2017 AACR.

Androgen deprivation therapy (ADT) is first‐line palliative treatment in androgen receptor‐positive (AR+) salivary duct carcinoma (SDC), and response rates are 17.6–50.0%. We investigated potential primary ADT resistance mechanisms for their predictive value of clinical benefit from ADT in a cohort of recurrent/metastatic SDC patients receiving palliative ADT (n = 30). We examined mRNA expression of androgen receptor (AR), AR splice variant‐7, intratumoral androgen synthesis enzyme‐encoding genes AKR1C3, CYP17A1, SRD5A1 and SRD5A2, AR protein expression, ERBB2 (HER2) gene amplification and DNA mutations in driver genes. Furthermore, functional AR pathway activity was determined using a previously reported Bayesian model which infers pathway activity from AR target gene expression levels. SRD5A1 expression levels and AR pathway activity scores were significantly higher in patients with clinical benefit from ADT compared to those without benefit. Survival analysis showed a trend toward a longer median progression‐free survival for patients with high SRD5A1 expression levels and high AR pathway activity scores. The AR pathway activity analysis, and not SRD5A1 expression, also showed a trend toward better disease‐free survival in an independent cohort of locally advanced SDC patients receiving adjuvant ADT (n = 14) after surgical tumor resection, and in most cases a neck dissection (13/14 patients) and postoperative radiotherapy (13/14 patients). In conclusion, we are the first to describe that AR pathway activity may predict clinical benefit from ADT in SDC patients, but validation in a prospective study is needed.

Approximately 20% of patients with bladder cancer are diagnosed with muscle‐invasive disease (MIBC). The treatment involves radical cystectomy, but almost 50% of patients with MIBC eventually relapse and develop metastasis. The use of platinum‐based chemotherapy in the neoadjuvant setting or for metastatic patients has been shown to improve the overall survival in a subset of patients. Unfortunately, no biomarkers are available to select patients with MIBC who will benefit from chemotherapy or to monitor the efficacy of the treatment. Recently, long noncoding RNAs (lncRNAs) were shown to regulate a variety of processes involved in the development and progression of cancer, including bladder cancer. Moreover, several lncRNAs have been shown to play a role in chemotherapy resistance. Here, we analyzed lncRNA expression associated with response to platinum‐based chemotherapy in metastatic MIBC using data from the MiTranscriptome lncRNA expression database. Expression of the lncRNA, LINC00857, was found to be upregulated in tumors from patients that did not respond to platinum‐based chemotherapy. Moreover, high expression of LINC00857 is correlated with shorter recurrence‐free and overall survival of patients with MIBC. Knockdown of LINC00857 significantly decreased cell viability of bladder cancer cell lines through the induction of apoptosis. Furthermore, LINC00857 knockdown sensitized UM‐UC‐3 and T24 bladder cancer cells to cisplatin, via the negative regulation of the LMAN1 gene. Our data indicate that LINC00857 plays an important role in the regulation of response to platinum‐based chemotherapy. LINC00857 potentially could serve as a novel prognostic and predictive biomarker and might be a therapeutic target to overcome cisplatin resistance in patients with MIBC.

Purpose: Prostate cancer (PCa) is a leading cause of cancer-related death. Upon androgen-deprivation therapy, the disease may progress further to castration-resistant PCa (CRPC) with a poor prognosis. MicroRNAs (miRNAs) are small non-coding RNAs, which play crucial roles in gene regulation. The aim of our study is to find CRPC-associated miRNAs and to evaluate their functional role. Methods: In this study, 23 benign prostatic hyperplasia (BPH), 76 primary PCa, and 35 CRPC specimens were included. Total RNA extracted from tissue sections was used for miRNA profiling on the Affymetrix GSC 3000 platform. Subsequently, stem-loop RT-qPCR analysis was performed to validate the expression levels of selected miRNAs. PCa cell lines were transfected with miRNA mimics or inhibitors to evaluate the effects on cell proliferation, cell migration and cell invasion. Results: In our profiling study, several miRNAs were found to be deregulated in CRPC compared to primary PCa tissue, of which miR-205 (− 4.5-fold; p = 0.0009), miR-92b (− 3.1 fold; p < 0.0001) were downregulated and miR-3195 (5.6-fold; p < 0.0001), miR-3687 (8.7-fold; p = 0.0006) and miR-4417 (5.0-fold; p = 0.0005) were most upregulated. While KLK3, miR-21 and miR-141 expression levels in androgen-treated VCaP and LNCaP cells were increased, the expression levels of miR-3687 and miR-4417 were reduced. None of the miRNAs were androgen-regulated in the AR-negative PC3 cell line. Overexpression of miR-3687 reduced cell migration and cell invasion, whilst miR-3195 enhanced cell migration. Conclusion: We have identified several novel deregulated miRNAs in CRPC tissue, including two microRNAs that are potentially involved in tumor invasion. Our data support the hypothesized involvement of miRNAs in PCa tumorigenesis and progression to CRPC. The applicability of these miRNAs as novel biomarkers for CRPC remains to be further investigated.

In the last few years, susceptibility loci have been identified for urinary bladder cancer (UBC) through candidate-gene and genome-wide association studies. Prognostic relevance of most of these loci is yet unknown. In this study, we used data of the Nijmegen Bladder Cancer Study (NBCS) to perform a comprehensive evaluation of the prognostic relevance of all confirmed UBC susceptibility loci. Detailed clinical data concerning diagnosis, stage, treatment, and disease course of a population-based series of 1,602 UBC patients were collected retrospectively based on a medical file survey. Kaplan-Meier survival analyses and Cox proportional hazard regression were performed, and log-rank tests calculated, to evaluate the association between 12 confirmed UBC susceptibility variants and recurrence and progression in non-muscle invasive bladder cancer (NMIBC) patients. Among muscle-invasive or metastatic bladder cancer (MIBC) patients, association of these variants with overall survival was tested. Subgroup analyses by tumor aggressiveness and smoking status were performed in NMIBC patients. In the overall NMIBC group (n = 1,269), a statistically significant association between rs9642880 at 8q24 and risk of progression was observed (GT vs. TT: HR = 1.08 (95% CI: 0.76–1.54), GG vs. TT: HR = 1.81 (95% CI: 1.23–2.66), P for trend = 2.6×10⁻³). In subgroup analyses, several other variants showed suggestive, though non-significant, prognostic relevance for recurrence and progression in NMIBC and survival in MIBC. This study provides suggestive evidence that genetic loci involved in UBC etiology may influence disease prognosis. Elucidation of the causal variant(s) could further our understanding of the mechanism of disease, could point to new therapeutic targets, and might aid in improvement of prognostic tools.

Introduction: Salivary gland cancer (SGC) is a rare cancer for which systemic treatment options are limited. Therefore, it is important to characterize its genetic landscape in search for actionable aberrations, such as NTRK gene fusions. This research aimed to identify these actionable aberrations by combining NGS-based analysis of RNA (gene fusions) and DNA (single and multiple nucleotide variants, copy number variants, microsatellite instability and tumor mutational burden) in a large cohort of SGC patients. Methods: RNA and DNA were extracted from archival tissue of 121 patients with various SGC subtypes. Gene fusion analysis was performed using a customized RNA-based targeted NGS panel. DNA was sequenced using a targeted NGS panel encompassing 523 cancer-related genes. Cross-validation of NGS-based NTRK fusion detection and pan-TRK immunohistochemistry (IHC) was performed. Results: Fusion transcripts were detected in 50% of the cases and included both known (MYB-NFIB, MYBL1-NFIB, CRTC1-MAML2) and previously unknown fusions (including transcripts involving RET, BRAF or RAD51B). Only one NTRK fusion transcript was detected, in a secretory carcinoma case. Pan-TRK IHC (clone EPR17341) was false positive in 74% of cases. The proportion of patients with targets for genetically matched therapies differed among subtypes (salivary duct carcinoma: 82%, adenoid cystic carcinoma 28%, mucoepidermoid carcinoma 50%, acinic cell carcinoma 33%). Actionable aberrations were most often located in PIK3CA (n = 18, 15%), ERBB2 (n = 15, 12%), HRAS and NOTCH1 (both n = 9, 7%). Conclusions: Actionable genetic aberrations were seen in 53.7% of all SGC cases on the RNA and DNA level, with varying percentages between subtypes.