A photo-responsive chemical modulation of m6A RNA demethylase FTO

Advances in the investigation of N6-isopentenyl adenosine i6A RNA modification

Prenylation (isopentenylation), a key post-transcriptional modification with a hydrophobic prenyl group onto the biomacromolecules such as RNA and proteins, influences their localization and function. Prenyltransferases mediate this process, while cytokinin oxidases degrade the prenylated adenosine in plants. This review summarizes current progress in detecting prenylation modifications in RNA across species and their effects on protein synthesis. Advanced methods have been developed to label and study these modifications in vitro and in vivo, despite challenges posed by the inert chemical properties of prenyl groups. Continued advancements in bioorthogonal chemistry promise new tools for understanding the precise biological functions of prenylated RNA modifications and other related proteins.

Rational Design of RNA Demethylase FTO Inhibitors with Enhanced Antileukemia Drug-Like Properties

The fat mass and obesity-associated protein (FTO) is an RNA N⁶-methyladenosine (m⁶A) demethylase highly expressed in diverse cancers including acute myeloid leukemia (AML). To improve antileukemia drug-like properties, we have designed 44/ZLD115, a flexible alkaline side-chain-substituted benzoic acid FTO inhibitor derived from FB23. A combination of structure-activity relationship analysis and lipophilic efficiency-guided optimization demonstrates that 44/ZLD115 exhibits better drug-likeness than the previously reported FTO inhibitors, FB23 and 13a/Dac85. Then, 44/ZLD115 shows significant antiproliferative activity in leukemic NB4 and MOLM13 cell lines. Moreover, 44/ZLD115 treatment noticeably increases m⁶A abundance on the AML cell RNA, upregulates RARA gene expression, and downregulates MYC gene expression in MOLM13 cells, which are consistent with FTO gene knockdown. Lastly, 44/ZLD115 exhibits antileukemic activity in xenograft mice without substantial side effects. This FTO inhibitor demonstrates promising properties that can be further developed for antileukemia applications.

The regulation of N6-methyladenosine modification in PD-L1-induced anti-tumor immunity

There is growing evidence that programmed death ligand-1 (PD-L1) has exciting therapeutic efficacy in hematological malignancy and partial solid tumors. However, many patients still face failure with the treatment of immune checkpoint blockade because of PD-L1 expression regulation during transcription and post-transcription processes, including N6-methyladenosine (m6A). Similar to the epigenetic regulation in DNA and histones, recent research has revealed the essential regulation of m6A modification in RNA nuclear export, metabolism and translation. Recent studies have shown that m6A-induced PD-L1 expression emerges as one of the main reasons for the immunological alteration in this process and contributes to the failure of T cell-induced anti-tumor immunity. The results of preclinical studies demonstrate the potential of m6A-targeted therapy in combination with immune checkpoint blockade. The comprehensive expression of m6A-related genes also provided the possibility to indicate the prognosis and to optimize the treatment for patients of various cancer types. In this review, we focus on the m6A modification in PD-L1 mRNA as well as the regulation of PD-L1 expression in cancer cells and summarize its clinical value in anti-PD-L1 cancer immune therapy.