8bn8
METTL3-METTL14 heterodimer bound to the SAM competitive small molecule inhibitor STM3006METTL3-METTL14 heterodimer bound to the SAM competitive small molecule inhibitor STM3006
Structural highlights
FunctionMTA70_HUMAN N6-methyltransferase that methylates adenosine residues of some RNAs and acts as a regulator of the circadian clock, differentiation of embryonic stem cells and primary miRNA processing. N6-methyladenosine (m6A), which takes place at the 5'-[AG]GAC-3' consensus sites of some mRNAs, plays a role in the efficiency of mRNA splicing, processing, translation efficiency, editing and mRNA stability (PubMed:22575960, PubMed:24284625, PubMed:25719671, PubMed:25799998, PubMed:26321680, PubMed:26593424, PubMed:9409616). M6A regulates the length of the circadian clock: acts as a early pace-setter in the circadian loop by putting mRNA production on a fast-track for facilitating nuclear processing, thereby providing an early point of control in setting the dynamics of the feedback loop (By similarity). M6A also acts as a regulator of mRNA stability: in embryonic stem cells (ESCs), m6A methylation of mRNAs encoding key naive pluripotency-promoting transcripts results in transcript destabilization, promoting differentiation of ESCs (By similarity). M6A also takes place in other RNA molecules, such as primary miRNA (pri-miRNAs) (PubMed:25799998). Mediates methylation of pri-miRNAs, marking them for recognition and processing by DGCR8 (PubMed:25799998).[UniProtKB:Q8C3P7][1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedTherapies that enhance antitumor immunity have altered the natural history of many cancers. Consequently, leveraging nonoverlapping mechanisms to increase immunogenicity of cancer cells remains a priority. Using a novel enzymatic inhibitor of the RNA methyl-transferase METTL3, we demonstrate a global decrease in N6-methyladenosine (m6A) results in double-stranded RNA (dsRNA) formation and a profound cell-intrinsic interferon response. Through unbiased CRISPR screens, we establish dsRNA-sensing and interferon signaling are primary mediators that potentiate T-cell killing of cancer cells following METTL3 inhibition. We show in a range of immunocompetent mouse models that although METTL3 inhibition is equally efficacious to anti-PD-1 therapy, the combination has far greater preclinical activity. Using SPLINTR barcoding, we demonstrate that anti-PD-1 therapy and METTL3 inhibition target distinct malignant clones, and the combination of these therapies overcomes clones insensitive to the single agents. These data provide the mole-cular and preclinical rationale for employing METTL3 inhibitors to promote antitumor immunity in the clinic. SIGNIFICANCE: This work demonstrates that METTL3 inhibition stimulates a cell-intrinsic interferon response through dsRNA formation. This immunomodulatory mechanism is distinct from current immunotherapeutic agents and provides the molecular rationale for combination with anti-PD-1 immune-checkpoint blockade to augment antitumor immunity. This article is featured in Selected Articles from This Issue, p. 2109. Inhibition of METTL3 Results in a Cell-Intrinsic Interferon Response That Enhances Antitumor Immunity.,Guirguis AA, Ofir-Rosenfeld Y, Knezevic K, Blackaby W, Hardick D, Chan YC, Motazedian A, Gillespie A, Vassiliadis D, Lam EYN, Tran K, Andrews B, Harbour ME, Vasiliauskaite L, Saunders CJ, Tsagkogeorga G, Azevedo A, Obacz J, Pilka ES, Carkill M, MacPherson L, Wainwright EN, Liddicoat B, Blyth BJ, Albertella MR, Rausch O, Dawson MA Cancer Discov. 2023 Oct 5;13(10):2228-2247. doi: 10.1158/2159-8290.CD-23-0007. PMID:37548590[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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