Clin Cancer Res. 2018 Dec 26. pii: clincanres.3230.2018. doi: 10.1158/1078-0432.CCR-18-3230. [Epub ahead of print]
Epigenetic silencing of miRNA-338-5p and miRNA-421 drives SPINK1-positive prostate cancer.
Bhatia V1, Yadav A1, Tiwari R1, Nigam S1, Goel S1, Carskadon S2, Gupta N3, Goel A4, Palanisamy N5, Ateeq B6.
Author information
- 1
- Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur.
- 2
- Henry Ford Health System.
- 3
- Pathology, Henry Ford Health System.
- 4
- Department of Urology,, King George's Medical University.
- 5
- Urology, Henry Ford Health System.
- 6
- Biological Sciences & Bioengineering, Indian Institute of Technology Kanpur bushra@iitk.ac.in.
Abstract
PURPOSE:
Serine Peptidase Inhibitor, Kazal type-1 (SPINK1) overexpression defines the second most recurrent and aggressive prostate cancer (PCa) subtype. However, the underlying molecular mechanism and pathobiology of SPINK1 in PCa remains largely unknown.
EXPERIMENTAL DESIGN:
MicroRNA-prediction tools were employed to examine the SPINK1-3'UTR for miRNAs binding. Luciferase reporter assays were performed to confirm the SPINK1-3'UTR binding of shortlisted miR-338-5p/miR-421. Further, miR-338-5p/-421 overexpressing cancer cells (SPINK1-positive) were evaluated for oncogenic properties using cell-based functional assays and mice xenograft model. Global gene expression profiling was performed to unravel the biological pathways altered by miR-338-5p/-421. Immunohistochemistry and RNA in-situ hybridization was carried-out on PCa patients' tissue microarray for SPINK1 and EZH2 expression respectively. Chromatin immunoprecipitation assay was performed to examine EZH2 occupancy on the miR-338-5p/-421 regulatory regions. Bisulfite sequencing and methylated DNA-immunoprecipitation was performed on PCa cell lines and patients' specimens.
RESULTS:
We established a critical role of miRNA-338-5p/-421 in post-transcriptional regulation of SPINK1. Ectopic expression of miRNA-338-5p/-421 in SPINK1-positive cells abrogate oncogenic properties including cell-cycle progression, stemness and drug resistance, and show reduced tumor burden and distant metastases in mice model. Importantly, we show SPINK1-positive PCa patients exhibit increased EZH2 expression, suggesting its role in epigenetic silencing of miRNA-338-5p/-421. Furthermore, presence of CpG dinucleotide DNA methylation marks on the regulatory regions of miR-338-5p/-421 in SPINK1-positive PCa cells and patients' specimens confirms epigenetic silencing.
CONCLUSION:
Our findings revealed that miRNA-338-5p/-421 are epigenetically silenced in SPINK1-positive PCa, while restoring the expression of these miRNAs using epigenetic drugs or synthetic mimics could abrogate SPINK1-mediated oncogenesis.
Copyright ©2018, American Association for Cancer Research.
- PMID:
- 30587549
- DOI:
- 10.1158/1078-0432.CCR-18-3230