Identification of Potent and Selective Inhibitors of Fat Mass Obesity-Associated Protein Using a Fragment-Merging Approach

Abstract

Fat mass obesity-associated protein (FTO) is a DNA/RNA demethylase involved in the epigenetic regulation of various genes and is considered a therapeutic target for obesity, cancer, and neurological disorders. Here, we aimed to design novel FTO-selective inhibitors by merging fragments of previously reported FTO inhibitors. Among the synthesized analogues, compound 11b, which merges key fragments of Hz (3) and MA (4), inhibited FTO selectively over alkylation repair homologue 5 (ALKBH5), another DNA/RNA demethylase. Treatment of acute monocytic leukemia NOMO-1 cells with a prodrug of 11b decreased the viability of acute monocytic leukemia cells, increased the level of the FTO substrate N 6-methyladenosine in mRNA, and induced upregulation of MYC and downregulation of RARA, which are FTO target genes. Thus, Hz (3)/MA (4) hybrid analogues represent an entry into a new class of FTO-selective inhibitors.

Structure–Activity Relationships and Antileukemia Effects of the Tricyclic Benzoic Acid FTO Inhibitors

“…Rhein, meclofenamic acid (MA), fluorescein, FB23, and Dac51, which we previously developed, as well as N -CDPCB, FTO-2, and CS2, which were developed by others, are representative substrate-competitive FTO inhibitors, and most of these inhibitors show highly selective affinity for RNA demethylases. − 2OG analogs, such as R -2HG, have been reported to efficiently inhibit FTO demethylation by directly occupying the 2OG-binding site . In addition, 6MK and entacapone have been characterized as dual 2OG- and substrate-competitive FTO inhibitors. , Recently, two other dual 2OG- and substrate-competitive FTO inhibitors have been identified. , Inhibitors with undetermined modes of binding, such as Clausine E and Saikosaponin D, are natural products with a broad range of biological targets and activities. − Notably, among these small-molecule inhibitors, only the FB23 bioisosteres FB23-2 and Dac51, Saikosaponin D, and CS2 exhibit the anticipated antiproliferative activity in both cells and mouse models. ,,,, These FTO inhibitors may be used for probing RNA methylation status and for validating FTO as an anticancer drug target.…”

Recent Advances of m6A Demethylases Inhibitors and Their Biological Functions in Human Diseases

“…Importantly, research demonstrated that FTO could impair the self-renewal properties of GSCs to inhibit neurosphere formation without altering the growth of human neural stem cell neurospheres. Prakash and co-workers synthesized compound 21a ( Figure 4 ) as a potent FTO selectivity inhibitor (IC 50 = 0.087 μM) by merging the key fragments of compound 9a and MA [ 121 ]. Moreover, the ester prodrug 21b of compound 21a could reduce the viability of AML cells by downregulating MYC and upregulating RARA, which was consistent with previous reports on the anticancer effect of pharmacological FTO inhibition [ 37 , 39 ].…”

Implications of m6A methylation and microbiota interaction in non-small cell lung cancer: From basics to therapeutics

“…FTO and ALKBH5 primarily demethylate m6A-modified bases, with FTO being the first m6A demethylase identified, showing high demethylation activity for m6A, and ALKBH5 catalyzing the removal of m6A modifications from nuclear RNAs (mainly mRNA), thereby affecting metabolic disease and human obesity. FTO was the first m6A demethylase to be identified, showing high demethylation activity against m6A, which can affect metabolic diseases and the development of obesity in humans, while ALKBH5 can catalyze the removal of m6A modifications from nuclear RNA (mainly mRNA), which in turn can affect nuclear RNA export, metabolism and gene expression, and even fertility in mice (Zheng et al, 2013;Huang et al, 2020;Prakash et al, 2021). However, the current studies showed that although ALKBH5 and FTO are both m6A demethylases, they play different roles in the pathological development of NSCLC.…”