Abstract 2428: Cancer stem cells maintain stemness via autocrine activation of the IFN/JAK/STAT signaling pathway

Abstract

Abstract Interferons (IFNs) and Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling are best known for their roles in immunity. However, recent work has suggested that both IFNs and the JAK/STAT pathways are associated with tumor growth and progression, as well as the maintenance of cancer stem cell (CSC) populations. To better understand the regulation of the CSC population maintenance by the IFN/JAK/STAT signaling pathway, we enriched CSCs from a panel of non-small cell lung cancer (NSCLC) cell lines by using spheroid culture and determined the phosphorylation of STAT1. We found that sphere cells exhibit increased level of pSTAT1-Y701 compared to their corresponding bulk cells. We further determined the expression level of a few interferon-stimulated genes (ISGs) and found that sphere cells possess enhanced expression of ISG54 and ISG56 genes, which are normally induced by type I IFN (IFN-I), as well as IFNA and IFNB. These results indicate that the IFN-I/STAT1 signaling is highly activated in CSCs, which produce and secrete increased amount of IFN-I. To directly show the effect of IFN-I on the stemness of NSCLC cells, we treated NSCLC cells with IFNβ, and found that IFNβ can significantly enhance the expression of SOX2, a stem cell-specific transcription factor; Inhibition of the JAK signaling blocked both basal and IFNβ-induced SOX2 expression. In addition, knockdown of STAT1 also reduced SOX2 expression, indicating that STAT1 activation plays an important role in mediating IFN-induced enhancement of stemness. Finally, the ChIP assay demonstrated that STAT1 protein can bind to the promoter region of the SOX2 gene to serve as a transcription factor. In summary, our results indicate that CSCs produce and secrete IFN-I via their enhanced JAK/STAT1 signaling. The secreted IFN-I can bind to the receptor on the CSCs, further activate their JAK/STAT1 signaling, promoting the expression of SOX2 and maintenance of stemness of CSCs via an autocrine manner. Citation Format: Aidan Li, Xuetao Bai, Na Li, Shurui Cai, Ananya Banerjee, Kousalya Lavudi, Linzhou Wang, Qianyun Ge, Yajing Yang, Qi-En Wang. Cancer stem cells maintain stemness via autocrine activation of the IFN/JAK/STAT signaling pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2428.