Gene-Specific Demethylation as Targeted Therapy in MDS
Abstract
Background/Hypothesis/Objective: DNA methylation (the addition of a methyl group, "a flag" to a DNA molecule) is a mechanism involved in turning off certain genes. Incorrect DNA methylation can lead to cancers, and numerous studies have established a link between abnormal DNA methylation and cancer. To date, the causes triggering the abnormal methylation in cancer remain unknown. RNAs are biological molecules constantly produced in our body and essential for multiple biological processes. DNA methyltransferases are the enzymes responsible for the addition of methyl groups to the DNA. Recently, we have identified a specific class of RNAs able to interact with the DNA methyltransferase 1 (DNMT1). We termed this class of functional RNAs DNMT1-interacting RNAs "DiRs." DiRs inhibit DNMT1 methylation activity, preventing methylation of the DiRs expressing genomic regions. Based on these findings, we hypothesize that DNA methylation changes can be corrected by RNAs. We aim to demonstrate that (a) by inducing the DiRs within targeted methylated genes or (b) by utilizing short pieces of DNA or RNA, called oligonucleotides, mimicking the function of DiRs and able to specifically target methylated loci, we will be able to reduce level of methylation and consequently rescue the expression of the respective silent gene, inhibiting cancer growth. The critical question to be addressed by the proposed project: We have already achieved "proof-of-principle" by (1) inducing gene-selective demethylation and expression of the CEBPA gene through overexpression of its cognate DiR, and (2) introducing oligonucleotides targeting abnormal methylated loci and designed in such a way that RNA molecules can be synthesized locally induced. In the proposed project, we will address whether a similar approach can activate another gene, P15 (CDKN2B), a gene regulating blood production and the one most frequently turned off by abnormal methylation in myelodysplastic syndromes (MDS). First, we will employ laboratory cell lines; afterwards, the same strategy will be attempted in primary MDS cells to restore proper P15 gene methylation and gene expression levels. The specific bone marrow failure (BMF) disease to be researched: MDS, classified as an acquired BMF condition with a risk of progression to acute myeloid leukemia (AML) in approximately 30 percent of the cases, are a group of blood disorders in which the bone marrow, the organ responsible for the production of all blood cells, is malfunctioning. MDS affects primarily elderly people, and its incidence is estimated of about 14,000 new cases per year. As the percentage of the older population increases, understanding of the causes behind MDS onset becomes even more relevant. Incorrect DNA methylation is considered a dominant mechanism to turn off genes suppressing tumor formation termed "tumor suppressor genes," especially in the evolution of MDS to AML. Innovative aspects of the proposed project: To date, the most prominent demethylating agents used in the treatment of MDS are Azacitidine (Vidaza) and Decitabine (Dacogen). However, their global non-specific demethylation leads to cytotoxicity that limits their clinical usefulness. Introduction of this novel gene-specific demethylating approach has the potential to revolutionize the treatment of MDS and other diseases triggered by DNA methylation abnormalities with great advantages over the existing hypomethylating-based protocols. These advantages include (i) high gene specificity, (ii) lower cytotoxicity, and (iii) absence of drug-based off-target side effects. The impact of the proposed research might have on the BMF field: This study holds promise for genuine targeted therapy. If successful, these tools could be of fundamental scientific importance in understanding the role of DNA methylation in MDS. In addition, over the longer term, it could serve as the basis for the development of novel therapeutic agents of pote
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 04, 2016
- Source ID
- W81XWH1510161
Entities
People
- Daniel G Tenen
Organizations
- Beth Israel Deaconess Medical Center
- United States Army