Rational Design and Optimization of m⁶A-RNA Demethylase FTO Inhibitors as Anticancer Agents

Aberrant regulation of N-6-methyladenosine (m(6)A) RNA modification has been implicated in the progression of multiple diseases, including cancer. Previously, we identified a small molecule inhibitor of the m(6)A demethylase fat mass- and obesity-associated protein (FTO), which removes both m(6)A and N-6,2 '-O-dimethyladenosine (m(6)A(m)) RNA modifications. In this work, we describe the rational design and optimization of a new class of FTO inhibitors derived from our previous lead FTO-04 with nanomolar potency and high selectivity against the homologous m(6)A RNA demethylase ALKBH5. The oxetanyl class of compounds comprise competitive inhibitors of FTO with potent antiproliferative effects in glioblastoma, acute myeloid leukemia, and gastric cancer models where lead FTO-43 demonstrated potency comparable to clinical chemotherapeutic 5-fluorouracil. Furthermore, FTO-43 increased m(6)A and m(6)A(m) levels in a manner comparable to FTO knockdown in gastric cancer cells and regulated Wnt/PI3K-Akt signaling pathways. The oxetanyl class contains significantly improved anticancer agents with a variety of applications beyond glioblastoma.