Helicase-like transcription factor (HLTF)-deleted CDX/TME model of colorectal cancer increased transcription of oxidative phosphorylation genes and diverted glycolysis to boost S-glutathionylation in lymphatic intravascular metastatic niches

Abstract

Helicase-like transcription factor (HLTF) also known as SMARCA3, protects genome integrity. A tumor suppressor, HLTF is expressed in tumor cells but not in the tumor microenvironment (TME) in early-stage colorectal cancer (CRC). With disease progression, there is high concordance between epigenetic silencing of HLTF in CRC cells and negligible HLTF expression in the TME. We developed a cell line-derived xenograft (CDX) model and show for the first time that HLTF-deletion in cancer cells and the TME results in metabolic reprogramming that mitigates oxidative stress in lymphatic intravascular metastatic niches. The two metabolic pathways that derive energy from glucose—glycolysis and oxidative phosphorylation (OXPHOS)—are variously utilized by cancer cells depending upon the TME. HIF-1α, a master regulator of glycolysis, was eliminated from a role in reprogramming metabolism to satisfy CDX energetic requirements by RNAseq and spatial transcriptomics. Variability in the gut microbiome, with a putative role in altered metabolism, was also eliminated. HLTF-deleted cancer cells recovered from DNA damage at a transcriptomic level induction of DNA repair and OXPHOS genes linked to an amoeboid-associated phenotype at the tumor border (confocal microscopy). HLTF-deleted cancer and endothelial cells of lymphatic (PDPN) intravascular niches in the TME shared a site-specific protein S-glutathionylation signature (2D DIGE, MALDI-TOF/TOF mass spectrometry) for three glycolytic enzymes (PGK1 Cys379/380, PGAM1 Cys55, ENOA1 Cys119) that diverted glycolysis in support of continued glutathione biosynthesis. The collective absence of HLTF/Hltf from tumor and TME achieved redox homeostasis throughout the CDX and promoted metastasis.