Session: 604. Molecular Pharmacology and Drug Resistance: Myeloid Neoplasms: Poster I
Hematology Disease Topics & Pathways:
Research, Acute Myeloid Malignancies, AML, Translational Research, Diseases, Myeloid Malignancies, Biological Processes
The primary AML samples included BM and peripheral blood samples from newly diagnosed or relapsed/refractory (RR) AML patients (n= 13 and 13, respectively). Patients were classified as responders if they achieved complete remission (CR, n = 9), or non-responders if they failed to achieve CR (n= 17). First, bulk RNA-seq analysis was performed on 21 pre-treatment samples (9 responders and 12 non-responders) and 5 post-treatment samples (all non-responders) containing > 58% blasts. Gene ontology enrichment analysis showed that in the RR cohort, transcriptome signatures of immune system-related genes in pre-treatment samples were reduced in non-responders. In turn, comparisons of pre- and post-treatment gene expression in the RR cohort showed that IFN-stimulated genes (ISGs), reflecting IFN activation, were upregulated after treatment (e.g. post- vs. pre-treatment fold change: IFNGR2 2.4, CCL3 4.5, IRF8 3.6, p < 0.05).
To determine whether DEC-VEN induces ERV dsRNA known to stimulate ISGs, we analyzed the expression of 45 well-annotated ERVs in pre- and post-treatment samples from patients with RR AML. Differential expression analysis revealed significant upregulation of ERVFRD-2, ERVK3-1 and ERVK-27 following DEC-VEN treatment. We confirmed that mRNA levels of three ERVs (ERVFAD-1, ERVW-1, ERVK-7) were upregulated after DEC-VEN treatment in vitro in AML cell lines HL60 and MV4;11.
Next, to determine if ERV-derived dsRNA induces ISGs in a TANK-binding kinase 1 (TBK1)-dependent manner, we examined IFNB mRNA expression by HRVW-1 dsRNA in TBK1-deficient mouse embryonic fibroblasts (MEFs). ERV-dsRNA containing the 3' UTR, 5' UTR or ORF regions enhanced IFNB in wild-type MEFs but not in TBK1-deficient MEFs. These results were confirmed in AML cell lines; ERVFRD-1 dsRNA of ORF increased IFNB, 3.0- and 220-fold, and IFI27, 4.5- and 1,143-fold in HL-60 and MV4;11, respectively. TBK1 inhibitor GSK8612 diminished DEC-Ven-induced IFNB and IFI27 mRNA expression in HL-60 and MV4;11.
Finally, to investigate changes in T cell signatures after DEC-VEC treatment in the AML microenvironment, we utilized scRNA seq data of 12 BM samples (39,607 cells in total) from 8 patients with RR AML (4 responders, 4 non-responders, and 4 pre- and post-treatment pairs). In AML cell clusters, MX1 and IFITM, genes involved in cellular antiviral response, were significantly up-regulated after DEC-VEN treatment in all analyzed samples. Focusing on the responders, IFI27, an INF alpha inducible gene, was significantly increased. Sub-classification of T cells from scRNA-seq profiling showed that CD8+ T and CD8 CTL cells were significantly increased after treatment, especially in responders. Furthermore, significant increases in gene expression of cytotoxicity-related genes such as PRF1 and NKG7, and CD2, an activator of T cell differentiation and IFNγ production, were observed in CD8+ T cells in responders.
Taken together, these results indicated that DEC-VEN treatment reactivates ERV dsRNA, TBK1 signaling with upregulation of ISGs, translating into CD8+ T-cell activation which may contribute to therapeutic efficacy. These findings provide insights into the immunomodulatory effects of DEC-VEN therapy. To address anti-leukemia mechanisms of IFN response by ERV reactivation, we are currently studying the impact of TBK1 inhibitors on patient-derived AML cells co-cultured with T cells under DEC-VEN treatment using cytometry by time of flight (CyTof) analysis, and these results will be reported.
Disclosures: Maiti: Lin Biosciences: Research Funding; Indapta Therapeutics: Research Funding; Inspirna: Research Funding; Chimeric Therapeutics: Research Funding; Hibercell Inc.: Research Funding; CytoMed Therapeutics: Research Funding. DiNardo: Foghorn: Research Funding; Cleave: Research Funding; Schrodinger: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Loxo: Research Funding; Rigel: Research Funding; Astellas: Consultancy, Honoraria; Gilead: Consultancy; GenMab: Consultancy, Honoraria, Other: data safety board; Amgen: Consultancy; ImmuneOnc: Research Funding; GSK: Consultancy, Honoraria; Notable Labs: Honoraria; Astex: Research Funding; Servier: Consultancy, Honoraria, Other: meetingsupport, Research Funding; Immunogen: Honoraria; Riegel: Honoraria; Genetech: Honoraria; BMS: Consultancy, Honoraria, Research Funding; AstraZeneca: Honoraria; Abbvie: Consultancy, Honoraria, Research Funding; Stemline: Consultancy. Andreeff: SentiBio: Current holder of stock options in a privately-held company, Honoraria, Research Funding; Roivant: Honoraria; Chimerix: Current holder of stock options in a privately-held company; Syndax: Honoraria, Research Funding; Ona: Honoraria; Ellipses: Research Funding; Kintor Pharmaceutical: Research Funding; Sellas: Honoraria, Research Funding; Glycomimetics: Honoraria; Eterna: Current holder of stock options in a privately-held company, Honoraria, Research Funding; Paraza: Honoraria; Aptose: Honoraria; Oxford Biomedical: Research Funding; Boehringer-Ingelheim: Honoraria; Daiichi-Sankyo: Research Funding; Oncolyze: Current holder of stock options in a privately-held company. Konopleva: Intellisphere: Speakers Bureau; Vincerx: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: clinical trials, Research Funding; Syndax: Membership on an entity's Board of Directors or advisory committees; Auxenion GmbH: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Other: clinical trials; Novartis: Membership on an entity's Board of Directors or advisory committees; Menarini Group: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Aventis: Consultancy; MEI Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Klondike Biopharma: Research Funding; Legend Biotech: Membership on an entity's Board of Directors or advisory committees; Servier: Speakers Bureau; Curis: Consultancy; Dark Blue Therapeutics: Membership on an entity's Board of Directors or advisory committees; Adaptive: Consultancy.
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