miR-3140 suppresses tumor cell growth by targeting BRD4 via its coding sequence and downregulates the BRD4-NUT fusion oncoprotein
SCIENTIFIC REPORTS
Authors: Tonouchi, Erina; Gen, Yasuyuki; Muramatsu, Tomoki; Hiramoto, Hidekazu; Tanimoto, Kousuke; Inoue, Jun; Inazawa, Johji
Abstract
Bromodomain Containing 4 (BRD4) mediates transcriptional elongation of the oncogene MYC by binding to acetylated histones. BRD4 has been shown to play a critical role in tumorigenesis in several cancers, and the BRD4-NUT fusion gene is a driver of NUT midline carcinoma (NMC), a rare but highly lethal cancer. microRNAs (miRNAs) are endogenous small non-coding RNAs that suppress target gene expression by binding to complementary mRNA sequences. Here, we show that miR-3140, which was identified as a novel tumor suppressive miRNA by function-based screening of a library containing 1090 miRNA mimics, directly suppressed BRD4 by binding to its coding sequence (CDS). miR-3140 concurrently downregulated BRD3 by bind to its CDS as well as CDK2 and EGFR by binding to their 3' untranslated regions. miR-3140 inhibited tumor cell growth in vitro in various cancer cell lines, including EGFR tyrosine kinase inhibitor-resistant cells. Interestingly, we found that miR-3140 downregulated the BRD4-NUT fusion protein and suppressed in vitro tumor cell growth in a NMC cell line, Ty-82 cells. Furthermore, administration of miR-3140 suppressed in vivo tumor growth in a xenograft mouse model. Our results suggest that miR-3140 is a candidate for the development of miRNA-based cancer therapeutics.
BET Proteins: An Approach to Future Therapies in Transplantation
AMERICAN JOURNAL OF TRANSPLANTATION
Authors: Suarez-Alvarez, B.; Rodriguez, R. M.; Ruiz-Ortega, M.; Lopez-Larrea, C.
Abstract
In order to develop new efficient therapies for organ transplantation, it is essential to acquire a comprehensive knowledge of the molecular mechanisms and processes, such as immune activation, chronic inflammation, and fibrosis, which lead to rejection and longterm graft loss. Recent efforts have shed some light on the epigenetic regulation associated with these processes. In this context, the bromo and extraterminal (BET) family of bromodomain proteins (BRD2, BRD3, BRD4, and BRDT) have emerged as major epigenetic players, connecting chromatin structure with gene expression changes. These proteins recognize acetylated lysines in histones and master transcription factors to recruit regulatory complex and, finally, modify the transcriptional program. Recent studies indicate that BET proteins are essential in the NF-kB-mediated inflammatory response, during the activation and differentiation of Th17-immune cells, and in profibrotic processes. Here, we review this new body of data and highlight the efficiency of BET inhibitors in several models of diseases. The promising results obtained from these preclinical models indicate that it may be time to translate these outcomes to the transplantation field, where epigenetics will be of increasing value in the coming years.