GSE161961
Hltf-deletion from the TME in a CDX model of CRC reprogrammed the human transcriptome-S-nitroso-proteome to promote inflammation and redirect metastasis
Hypermethylation of helicase-like transcription factor (HLTF) in colorectal cancer (CRC) cells occurs more frequently in men than women. Progressive epigenetic silencing of HLTF in tumor cells is accompanied by negligible expression in the tumor microenvironment (TME). Cell line-derived xenografts were established in control (Hltf+/+) and Hltf-deleted male Rag2-/-IL2rg-/- mice by direct orthotopic microinjection of HLTF+/+HCT116 cells into the submucosa of the cecum. Combinatorial induction of IL6 and S100A8/A9 in the Hltf-deleted TME with ICAM-1 and IL8 in the primary tumor activated a positive feedback loop. The proinflammatory niche produced a major shift in CDX metastasis to peritoneal dissemination compared to controls. Inducible nitric oxide (iNOS) gene expression and transactivation of the iNOS-S100A8/A9 signaling complex in Hltf-deleted TME reprogrammed the human S-nitroso-proteome. S-nitroso (SNO) proteins POTEE, TRIM52 and UN45B are S-nitrosylated on the conserved I/L-X-C-X2-D/E motif indicative of iNOS-S100A8/A9-mediated S-nitrosylation. 2D-DIGE and protein identification by MALDI-TOF/TOF mass spectrometry authenticated S-nitrosylation of 53 individual cysteines in half-site motifs (I/L-X-C or C-X-X-D/E) in CDX tumors. POTEE-SNO in CDX tumors is both a general S-nitrosylation target and an iNOS-S100A8/A9 site-specific (Cys638) target in the Hltf-deleted TME. REL is an example of convergence of transcriptomic-S-nitroso-proteomic signaling. The gene is transcriptionally activated in CDX  tumors with an Hltf-deleted TME, and REL-SNO (Cys143) is found in primary CDX tumors and all metastatic sites. Primary CDX tumors from Hltf-deleted TME shared 60% of their S-nitroso-proteome with all metastatic sites. Forty percent of SNO-proteins from primary CDX tumors were variably expressed at metastatic sites. Global S-nitrosylation of proteins in pathways related to cytoskeleton and motility is strongly implicated in the metastatic dissemination of CDX tumors. Hltf-deletion from the TME plays a major role in the pathogenesis of inflammation and links protein S-nitrosylation in primary CDX tumors with spatiotemporal continuity in metastatic progression even when the tumor cells express HLTF. Overall design: HCT116 cells that express HLTF were paced in mice that either do (control) or do not (test) express the Hltf gene. Resultant, primary CDX tumors were excised, profiled with RNAseq, and subjected to species specific mapping, Comparisons of gene expresison profiles for tumors (human) and the tumor microenvironment (mouse) were generated.