A10N
Inflammatory lung microenvironment in lung cancer-associated pulmonary hypertension
Tumor-associated macrophages (TAMs) have been shown to be a major contributor to the pathogenesis of lung cancer (LC) and lung cancer-associated pulmonary hypertension (LC-PH), whereas the precise activation/polarization state of macrophages invading lung tumors and the associated pulmonary vasculature (PVAMs, pulmonary vascular-associated macrophages) has not yet been investigated. Multiplex immunofluorescence staining of lung sections from LC-PH patients, multi-omics of FACS-sorted primary macrophages from lung biopsies and in vitro macrophage-lung cancer interaction models, and cellular functional studies revealed that PVAMs have dual phenotypic properties (M1≈M2), whereas TAMs are more M2-like. Integrated analysis of RNA-seq and ATAC-seq from primary lung cancer macrophages, identified a potential role of long non-coding RNA (lncRNAs) such as ADPGK-AS1-and protein-coding gene targets–transcription factors (TFs) such as FOS like 2 (FOSL2), Forkhead Box O3 (FOXO3), and Krueppel-Like Factor 9 (KLF9), in vitro TAMs and PVAMs models
LncRNAs regulate gene networks, but their role in macrophages is still largely unknown. Both M1-like and M2-like macrophages exhibit upregulation of the lncRNA ADPGK-AS1, with greater upregulation observed in M2-like macrophages, in macrophages co-cultured with tumor cells, and PVAMs. Further, the lncRNA ADPGK-AS1 binds to the mitochondrial ribosomal protein MRPL35, increasing tricarboxylic acid cycle (TCA) activity and mitochondrial fission, which is associated with an increased number of mitochondria and a phenotypic switch to a tumor-promoting cytokine release profile. Macrophage-specific knockdown of ADPGK-AS1 induces a metabolic and phenotypic (cytokine profile, reactive oxygen species production) switch to a tumor-suppressive status and inhibits pathological features of lung tumor cells and IPAH pulmonary vascular cells (iPVCs) in vitro (co-cultures), ex vivo (human tumor-precision lung slices), and in vivo (co-injection of macrophages and tumor cells).
Our subsequent studies have shown that ADPGK-AS1 drives FOSL2 expression after nuclear translocation, and FOSL2 then interacts with multiple TF clusters to initiate the M2 transcriptional program in TAMs and the dual M1≈M2 transcriptional program in PVAMs. Furthermore, a positive feedback loop between FOSL2, FOXO3, and KLF9 drives chromatin modifications that trigger distinct pathological mechanisms in TAMs and PVAMs. Thus, our previous research has shown that modulation of macrophage-specific ADPGK-AS1, FOSL2, FOXO3, and KLF9 and/or their downstream mechanisms in lung cancer may be a potential treatment option in lung cancer and beyond. Our aim for the next funding period is to provide the bases for potential therapeutic approaches to LC-PH. To reach this goal we need to: (1) identify the role of ADGPK1-AS1 in regulating PVAMs mitochondria and phenotypic state in LC-PH; (2) dissect the mechanism of FOSL2-FOXO3-KLF9 axis driven chromatin remodeling to understand the epigenomic and genomic landscape of TAMs and PVAMs; (3) develop and validate novel therapeutic cell specific approaches for targeting ADPGK-AS1, FOSL2, FOXO3, KLF9 and/or the identified downstream genes and (4) map the spatiotemporal ADPGK-AS1, FOSL2, FOXO3, KLF9 network and/or the identified downstream target genes in companion with a detailed analysis of the cellular architecture of the LC-PH perivascular niche for better insight into and therapeutic targeting of the natural lung cancer/pulmonary vascular microenvironment in LC-PH.
