Long non-coding RNA DBCCR1-003 regulate the expression of DBCCR1 via DNMT1 in bladder cancer

Abstract

BackgroundMany long non coding RNAs have been identified as key modulators in cancer development. A lncRNA, DBCCR1-003, derived from the locus of tumor suppressor gene DBCCR1 (deleted in bladder cancer chromosome region 1), has unknown function. In the present study, we explored function and molecular mechanism of DBCCR1-003 in bladder cancer (BC) development.MethodsWe evaluated the expression levels of DBCCR1-003 in tissues and cells with western blot and quantitative real-time polymerase chain reaction. Multiple approaches including chromatin immunoprecipitation assay and RNA immunoprecipitation were used to confirm the direct binding of DBCCR1-003 to DNMT1. The recombinant vector overexpressing DBCCR1-003 was constructed. Cell proliferation assay, colony formation assay and flow cytometric analysis were employed to measure the role of DBCCR1-003 in regulation of cell proliferation, cycle and apoptosis.ResultsFirstly we detected the expression of DBCCR1-003, DBCCR1, DNMT1 (DNA methyltransferase 1) and DNA methylation in the promoter of DBCCR1. We found low expression of DBCCR1-003, same as DBCCR1, while high expression of DNMT1 and hypermethylation of DBCCR1 gene promoter in BC tissues and T24 cells line. Further studies revealed that treatment of DNMT inhibitor, 5-aza-2-deoxycytidine(DAC), or overexpression of DBCCR1-003 led to increased DBCCR1 expression by reversion of promoter hypermethylation and DNMT1 binding to DBCCR1 promoter in T24 cells. Importantly, RNA immunoprecipitation (RIP) showed that DBCCR1-003 physically associates with DNMT1. The binding of them was increased with the inhibition of DBCCR1 promoter methylation, indicating that DBCCR1-003 may bind to DNMT1 and prevent DNMT1-mediated the methylation of DBCCR1. Furthermore, overexpression of DBCCR1-003 resulted in significant inhibition of T24 cells growth through the inducing G0/G1 arrest and apoptosis.ConclusionsTaken together, these findings demonstrated that a novel tumor suppressor DBCCR1-003 regulates the expression of DBCCR1 via binding to DNMT1 and preventing DNMT1-mediated the methylation of DBCCR1 in BC. LncRNA DBCCR1-003 may serve as a novel biomarker and therapeutic target for BC in future cancer clinic.Electronic supplementary materialThe online version of this article (doi:10.1186/s12935-016-0356-8) contains supplementary material, which is available to authorized users.

Identification of DBCCR1 as a suppressor in the development of lung cancer that is associated with increased DNA methyltransferase 1

“…found a correlation between low DBCCR1 level and high expression of DNMT1 in bladder cancer tissues. Their data support a direct inhibition of DBCCR1 through the DNMT1-mediated methylation of DBCCR1 promoter, which can be prevented by a long non-coding RNA derived from the DBCCR1 locus itself [30]. Complementary to these findings, the results of our study implied that DBCCR1 suppression and DNMT1 activation could be synergistically induced during tumor progression via positive feed-forward mechanisms.…”

“…Previously, DBCCR1 has been only suggested as a potential target of DNMT1-dependent methylation during development [29]. In a most recent report [30], the gene locus of DBCCR1 has been associated with DNMT1 activity in cancer. In this study, Qi D et al .…”

Incorporating DNA Methyltransferase Inhibitors (DNMTis) in the Treatment of Genitourinary Malignancies: A Systematic Review

“…Interestingly, zebularine increased radiation-induced DNA damage in bladder cancer cells and increased the radiation-induced tumor growth delay in a xenograft mouse model [76]. The function of DNMT1 in bladder cancer cell lines was recently discovered to be mediated by the long non-coding (lnc) RNA DBCCR1–003 derived from the locus of DBCCR1 tumor suppressor gene [77]. Habuchi et al previously demonstrated a role of the loss of DBCCR1 expression in transitional-cell bladder cancer [78].…”

“…Habuchi et al previously demonstrated a role of the loss of DBCCR1 expression in transitional-cell bladder cancer [78]. Qi et al [77] reported that DBCCR1–003 normally binds to DNMT1 and prevents the hypermethylation of DBCCR1 , thus allowing its expression. Treatment with decitabine or overexpression of DBCCR1–003 resulted into increased expression of DBCCR1 via reversed promoter hypermethylation and DNMT1 binding to DBCCR1–003 and promoter DBCCR1 in the T24 bladder cancer cell line.…”

“…Treatment with decitabine or overexpression of DBCCR1–003 resulted into increased expression of DBCCR1 via reversed promoter hypermethylation and DNMT1 binding to DBCCR1–003 and promoter DBCCR1 in the T24 bladder cancer cell line. This process led to significant growth inhibition of the cell line, suggesting DBCCR1–003 as a novel biomarker and potential treatment target [77]. In vivo experiments in patient-derived bladder cancer xenografts in mice showed that guadecitabine reduced DNA methylation at the p16 promoter region and reduced tumor growth [79].…”