Inhibition of METTL3 Results in a Cell-Intrinsic Interferon Response That Enhances Antitumor Immunity.
Guirguis, A.A., Ofir-Rosenfeld, Y., Knezevic, K., Blackaby, W., Hardick, D., Chan, Y.C., Motazedian, A., Gillespie, A., Vassiliadis, D., Lam, E.Y.N., Tran, K., Andrews, B., Harbour, M.E., Vasiliauskaite, L., Saunders, C.J., Tsagkogeorga, G., Azevedo, A., Obacz, J., Pilka, E.S., Carkill, M., MacPherson, L., Wainwright, E.N., Liddicoat, B., Blyth, B.J., Albertella, M.R., Rausch, O., Dawson, M.A.(2023) Cancer Discov 13: 2228-2247
- PubMed: 37548590 
- DOI: https://doi.org/10.1158/2159-8290.CD-23-0007
- Primary Citation of Related Structures:  
8BN8 - PubMed Abstract: 
Therapies 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.
Organizational Affiliation: 
Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.