Cell Type-Specific Transcriptome Profiling Reveals a Role for Thioredoxin During Tumor Initiation

Abstract

Neutrophils in the tumor microenvironment exhibit altered functions. However, the changes in neutrophil behavior during tumor initiation remain unclear. Here we used Translating Ribosomal Affinity Purification (TRAP) and RNA sequencing to identify neutrophil, macrophage and transformed epithelial cell transcriptional changes induced by oncogenic RasG12V in larval zebrafish. We found that transformed epithelial cells and neutrophils, but not macrophages, had significant changes in gene expression in larval zebrafish. Interestingly, neutrophils had more significantly down-regulated genes, whereas gene expression was primarily upregulated in transformed epithelial cells. The antioxidant, thioredoxin (txn), a small thiol that regulates reduction-oxidation (redox) balance, was upregulated in transformed keratinocytes and neutrophils in response to oncogenic Ras. To determine the role of thioredoxin during tumor initiation, we generated a zebrafish thioredoxin mutant. We observed an increase in wound-induced reactive oxygen species signaling and neutrophil recruitment in thioredoxin-deficient zebrafish. Transformed keratinocytes also showed increased proliferation and reduced apoptosis in thioredoxin-deficient larvae. Using live imaging, we visualized neutrophil behavior near transformed cells and found increased neutrophil recruitment and altered motility dynamics. Finally, in the absence of neutrophils, transformed keratinocytes no longer exhibited increased proliferation in thioredoxin mutants. Taken together, our findings demonstrate that tumor initiation induces changes in neutrophil gene expression and behavior that can impact proliferation of transformed cells in the early tumor microenvironment.

Damage-induced basal epithelial cell migration modulates the spatial organization of redox signaling and sensory neuron regeneration

“…By contrast, H 2 O 2 remained restricted to the wound edge in larvae burned in the presence of isotonic solution, displaying a similar localized pattern to that observed after mechanical injury ( Fig. 5F ) 53,57 . Quantification revealed that H 2 O 2 level at the wound edge was similar between control and isotonic treated larvae 6 hpb.…”

“…At 6 hours post burn, H 2 O 2 production was no longer localized to the wound edge in control burned larvae and had increased throughout the tailfin. By contrast, H 2 O 2 remained restricted to the wound edge in larvae burned in the presence of isotonic solution, displaying a similar localized pattern to that observed after mechanical injury (Figure 5F) (Jelcic et al, 2019; Korte et al, 2022). Quantification revealed that H 2 O 2 level at the wound edge was similar between control and isotonic treated larvae 6 hpw.…”

Staphylococcus aureus lipid factors modulate melanoma clustering and invasion in zebrafish

“…Increased recruitment of immune cells can promote cancer cell progression and metastasis [30, 31]. Larval zebrafish have an intact innate immune system which can be live imaged to evaluate immune cell infiltration and association with tumor cells [27, 32]. Using fluorescent reporters for neutrophils and macrophages, we imaged innate immune cell recruitment to the injection site.…”