hMENA11a loss activates Type I IFN and inflammatory pathways, and in turn PD-L1 expression, by activating the viral sensor RIG-I

PURPOSE To gain insights into molecular mechanisms accounting for the poor prognostic value of low hMENA11a expression. METHODS We analyzed the transcriptome by RNA-Seq and the secretome by Bio-Plex and ELISA of NSCLC cells, depleted of hMENA11a (si-11a) or total hMENA (si-hMENA(t)). ATAC-Seq was performed to identify epigenetic changes. RESULTS We observed the increase of different transcripts related to IFN signaling, such as STAT1, PD-L1 and IFNB1 in both freshly explanted and stabilized NSCLC si-11a cells. The increase of IFNβ secretion was also evidenced. We found that only in si-11a, but not in si-hMENA(t) cells, the activation of JAK/STAT1/IRF1 axis occurs. Moreover, ATAC-Seq revealed unknown regulatory regions in CD274 (PD-L1) locus in si-11a cells. We found that si-11a cells secrete different inflammatory molecules, including CXCL1, IL6 and IL8, and display higher activation of NF-kB. We demonstrated that hMENA11a silencing, which induces a critical cytoskeleton remodeling, increases the expression of the actin cytoskeleton-linked viral sensor RIG-I, which sustains both anti-viral and inflammatory responses. DISCUSSION These data support the role of hMENA11a isoform in restraining anti-viral and inflammatory pathways, by counteracting RIG-I. This may have crucial effects in patient prognosis and response to therapy. CONCLUSIONS Type I IFN pathway has been recently reported as crucial in resistance to immunotherapy with or without radiotherapy (4-6), thus we are evaluating the role of hMENA11a in response to ICB in NSCLC.