Erratum: CircNT5E promotes the proliferation and migration of bladder cancer via sponging miR-502-5p: Erratum.

[This corrects the article DOI: 10.7150/jca.53385.].

circSPECC1 promotes bladder cancer progression via regulating miR-136-5p/GNAS axis.

BACKGROUND: An increasing body of evidence suggest that circRNAs modulate various gene expression at the posttranscriptional level, affecting the development of cancers. Previous study suggested that circSPECC1 acted as an oncogene in some tumors, promoting the growth and metastasis of cancer cells. However, the role of circSPECC1 in bladder cancer (Bca) remains unknown. METHODS: RT-qPCR assay was applied to detect the expresion level of circRNA, miRNA and mRNA in Bca tissues and cells. CCK-8, cell colony formation and wound-healing assay were peformed to detect the effect of circSPECC1 on cell proliferation and migration. Nuclear mass separation, dual-luciferase reporter and RNA pull-down assay were used to investigate the molecular mechanisms underlying circSPECC1. RESULTS: In this study, we found that circSPECC1 was significantly up-regulated in Bca tissues and cell lines. Increased expression of circSPECC1 contribute to poor prognosis of Bca. Further tests showed that knockdown of circSPECC1 impaired the proliferation and migration of Bca cells. Mechanically, circSPECC1 sponged miR-136-5p to promote the mRNA and protein expression of GNAS. Besides, enforced expression of GNAS significantly reversed the proliferation and migration inhibition mediated by circSPECC1 suppression. CONCLUSION: In general, our study suggested that circSPECC1 contributed to the growth and metastasis of Bca and it is possible to become an ideal non-invasive biomarker for diagnosis and effective therapeutic target for treatment.

BTG2 suppresses renal cell carcinoma progression through N6-methyladenosine.

The biological functions of N6-methyladenosine (m6A) modification of mRNA have recently received a great deal of attention. In previous studies, m6A methylation modification has been shown to regulate mRNA fate and to be crucial for the progression and development of tumors. BTG2 (B-cell translocation gene 2) is a member of BTG/TOB anti-proliferative protein family. BTG2 could inhibit cell proliferation and migration and regulate the cell cycle progression. In this study, we confirm that BTG2 is frequently down-regulated in renal cell carcinoma (RCC) tissues and its low expression is associated with unfavorable prognosis and decreased m6A level. Moreover, we found that m6A methylation modifies the 5'UTR of BTG2 to promote its mRNA stability by binding to IGF2BP2. It has been shown that CRISPR/dCas13b-METLL3 can specifically increase BTG2 m6A modification to significantly increase its m6A and expression levels. Then m6A hypermethylation in BTG2 mRNA could dramatically inhibit RCC cells proliferation and migration, and induce cells apoptosis. Taken together, our data show that BTG2 functions as a tumor suppressor and is frequently silenced via m6A modification in RCC.

CircNT5E promotes the proliferation and migration of bladder cancer via sponging miR-502-5p.

Accumulating evidence suggest that circRNA RNAs (circRNAs) play important roles in tumor formation and development. circNT5E has been shown to be an oncogenic gene in several types of cancer, and the high expression of circNT5E lead to tumorigenesis and cancer progression. However, the precise role of circNT5E in bladder cancer (Bca) has not been characterized. In this study, we observed that circNT5E expression was augmented in Bca tissues compared with that in adjacent normal tissues, and its expression level was positively associated with larger tumor size and lower survival rate. Further experiments showed that suppression of circNT5E restrained the growth and metastasis of Bca cells in vitro. circNT5E was mainly distributed in the cytoplasm and it captured miR-502-5p to increase HOXC8 mRNA and protein expression. Moreover, decreased miR-502-5p obviously reversed the circNT5E silencing-mediated inhibition of Bca cell growth and migration. Thus, this study suggested that circNT5E may act as a pro-oncogene in the development and progression of Bca and it may become a useful tumor biomarker and promising therapeutic target for Bca treatment.

LncARSR sponges miR-129-5p to promote proliferation and metastasis of bladder cancer cells through increasing SOX4 expression.

Emerging evidences have indicated that long non-coding RNAs (lncRNAs) are potential biomarkers, playing important roles in the development of cancer. LncRNA Activated in RCC with Sunitinib Resistance (lncARSR) is a novel lncRNA that functions as a potential biomarker and is involved in the progression of cancers. However, the clinical significance and molecular mechanism of lncARSR in bladder cancer (Bca) remains unknow. In this study, we discovered that lncARSR was significantly up-regulated in bladder cancer. In addition, increased expression of lncARSR was positively correlated with higher histological grade and larger tumor size. Further experiments demonstrated that suppression of lncARSR attenuated the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) process of Bca cells. Mechanistically, lncARSR was mainly located in the cytoplasm and acted as a miRNA sponge to positively modulate the expression of Sex-determining region Y-related high-mobility-group box transcription factor 4 (SOX4) via sponging miR-129-5p and subsequently promoted the proliferation and metastasis of Bca cells, thus playing an oncogenic role in Bca pathogenesis. In conclusion, our study indicated that lncARSR plays a critical regulatory role in Bca cells and lncARSR may serve as a potential diagnostic biomarker and therapeutic target for bladder cancer.

A Synthetic Light-switchable System based on CRISPR Cas13a Regulates the Expression of LncRNA MALAT1 and Affects the Malignant Phenotype of Bladder Cancer Cells.

DNA sequences drive their various functions through post-transcriptional processes, using mRNA or lncRNA (long non-coding RNA), and this accommodates the gene network by using various RNA types. However, the tools necessary to regulate RNA molecules are few. Likewise, RNA knockdown techniques that can be artificially controlled have not been extensively explored. Here, we investigated a novel light-inducible synthetic system based on CRISPR-Cas13a that can be used for RNA knockdown and binding in cancer cells. Based on the techniques of synthetic molecular biology, we constructed a light sensor, which efficiently induced Cas13a protein expression after blue light illumination. We also chose a lncRNA, Metastasis-associated Lung Adenocarcinoma Transcript 1 (MALAT1), as the functional target and detected it in bladder cancer 5637 and T24 cells in order to demonstrate the application of our synthetic system. Fluorescence reporter assays and real-time quantitative PCR (qRT-PCR) were used to detect the expression of the target gene. Phenotypic experiments were also used to test the effects of our synthetic system in bladder cancers. The results showed that our synthetic light-switchable system could inhibit the expression of MALAT1, and the fluorescence activity of enhanced green fluorescent protein. Our novel system provides a new technique to study RNA functions in gene networks and for precise tumor treatments.

Expression of novel cancer/testis antigen TMEM31 increases during metastatic melanoma progression.

Cancer/testis (CT) antigens are promising targets for immunotherapy due to their restricted expression in the germ cells of the testis in healthy tissue and high immunogenicity. The aim of the present study was to determine whether transmembrane protein 31 (TMEM31) is a CT antigen and to investigate the pattern of TMEM31 expression during the progression of melanoma. The pattern of expression of human TMEM31 mRNA in multiple human tissues was determined through reverse transcription-polymerase chain reaction analysis. TMEM31 protein expression was analyzed in the human testis, in addition to 128 primary melanoma and 64 metastatic melanoma samples through immunohistochemistry analysis. TMEM31 was identified to be predominantly expressed in the testis and weakly expressed in the placenta. In addition, TMEM31 protein expression was detected in 120/190 (63.16%) melanoma samples (primary and metastatic). The intensity of TMEM31 staining in metastatic and primary melanomas was determined through semiquantitative integrated optical density (IOD) analysis, and identified to be significantly increased in metastatic melanoma compared with primary melanoma (0.24±0.03 vs. 0.09±0.01 IOD/area; P<0.001). The expression of TMEM31 protein was significantly increased in metastatic compared with primary melanoma samples (76.56 vs. 56.35%; P=0.017). The results of the present study suggest that TMEM31 is a novel CT antigen that serves an essential role in melanoma metastasis, in addition to being a potential immunotherapeutic target for the treatment of patients with melanoma.

Quantitation of rare circulating tumor cells by folate receptor α ligand-targeted PCR in bladder transitional cell carcinoma and its potential diagnostic significance.

Numerous attempts for detection of circulating tumor cells (CTC) have been made to develop reliable assays for early diagnosis of cancers. In this study, we validated the application of folate receptor α (FRα) as the tumor marker to detect CTC through tumor-specific ligand PCR (LT-PCR) and assessed its utility for diagnosis of bladder transitional cell carcinoma (TCC). Immunohistochemistry for FRα was performed on ten bladder TCC tissues. Enzyme-linked immunosorbent assay (ELISA) for FRα was performed on both urine and serum specimens from bladder TCC patients (n = 64 and n = 20, respectively) and healthy volunteers (n = 20 and n = 23, respectively). Western blot analysis and qRT-PCR were performed to confirm the expression of FRα in bladder TCC cells. CTC values in 3-mL peripheral blood were measured in 57 bladder TCC patients, 48 healthy volunteers, and 15 subjects with benign urologic pathologies by the folate receptor α ligand-targeted PCR. We found that FRα protein was overexpressed in both bladder TCC cells and tissues. The levels of FRα mRNA were also much higher in bladder cancer cell lines 5637 and SW780 than those of leukocyte. Values of FRα were higher in both serum and urine specimens of bladder TCC patients than those of control. CTC values were also higher in 3-mL peripheral blood of bladder TCC patients than those of control (median 26.5 Cu/3 mL vs 14.0 Cu/3 mL). Area under the receiver operating characteristic (ROC) curve for bladder TCC detection was 0.819, 95 % CI (0.738-0.883). At the cutoff value of 15.43 Cu/3 mL, the sensitivity and the specificity for detecting bladder cancer are 82.14 and 61.9 %, respectively. We concluded that quantitation of CTCs through FRα ligand-PCR could be a promising method for noninvasive diagnosis of bladder TCC.