meayamycin B

Meayamycin B (MAMB) is a potent, synthetic small-molecule spliceosome inhibitor and an analog of the natural product FR901464. It exerts its therapeutic potential by targeting the SF3B1 subunit of the U2 small nuclear ribonucleoprotein (snRNP) complex, which is a critical component of the spliceosome machinery. By inhibiting the spliceosome, meayamycin B modulates the alternative splicing of pre-mRNAs, particularly those encoding key regulators of apoptosis and the cell cycle, such as Mcl-1, Bcl-X, FAS, and Casp2. This leads to time- and dose-dependent cell cycle arrest in the G1 and G2/M phases and the induction of apoptosis. Research has demonstrated that meayamycin B is highly effective at subnanomolar concentrations against various acute leukemia cell lines, including those with acquired resistance to conventional chemotherapeutics like methotrexate, dexamethasone, and imatinib. It was developed by researchers at the University of Pittsburgh and has shown promising in vitro activity in both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) specimens.