Rohdjess, H. | bioRxiv Science

bioRxiv2026

Catabolism of extracellular glutathione is a driver of metastasis formation

Metastasizing cancer cells require metabolic plasticity to adapt to the microenvironment of the target organ. Analyzing metabolites in interstitial fluids, we found that the liver microenvironment is devoid of cystine but contains high concentrations of glutathione (GSH). Detailed mechanistic analysis revealed that cancer cells degrade extracellular GSH utilizing gamma-glutamyl-transferase (GGT) activity for provision of cysteine to support proliferation and prevent ferroptosis under cystine-free conditions. This was independent of system Xc- but required activity of glutamate-cysteine ligase (GCLC). GGT1 expression was associated with poor survival and upregulated in liver metastases of human breast cancer patients. Overexpression of Ggt1 in murine breast cancer cells enhanced their capacity for liver colonization and promoted lung metastases after orthotopic implantation. This identifies extracellular GSH catabolism as driver of metastasis that supports proliferation and oxidative stress resistance in metabolically challenging microenvironments.

cancer biology↗

bioRxiv2024

High interleukin-3 concentrations prime murine myeloid progenitor cells towards granulocytic differentiation

Impaired differentiation a key feature of many hematopoietic malignancies. To decipher the molecular processes underlying malignant transformation, it is important to understand the mechanisms regulating hematopoietic differentiation. Cell lines derived from transformed hematopoietic progenitors or from leukemia patients have proven to be valuable model systems for mechanistic investigations of hematopoiesis. In the present work, we investigated the cell-intrinsic differentiation capacity of the interleukin 3 (IL-3) dependent murine myeloid progenitor cell line 32D. We demonstrated that 32D cells have a cell-intrinsic granulocytic differentiation potential which requires the presence of high IL-3 concentrations in order to induce granulocytic priming. We also show that 32D cells still proliferate at comparable rates but lack granulocytic priming in the presence of intermediate IL-3 concentrations. This phenotypic plasticity is fully reversible and entirely depends on the IL-3 concentrations present in the culture media. RNA-seq analysis revealed that, among other myeloid genes, the expression of Csf3r is strongly induced exclusively in the presence of high IL-3 concentrations, likely explaining the granulocytic differentiation in response to G-CSF treatment. Together, our work provides detailed cellular and molecular insights into the phenotypic plasticity of 32D cells driven by different IL-3 concentrations and suggest culture conditions for different experimental set ups. Key pointsO_LI32D cells represent a murine myeloid cell line with endogenous granulocytic differentiation potential. C_LIO_LI32D cells present molecular and functional plasticity depending on their culture conditions. C_LIO_LIHigh IL-3 culture conditions prime 32D cells towards the granulocytic lineage. C_LIO_LILow IL-3 culture conditions lead to a reversible loss of the granulocytic differentiation potential of 32D cells while fully maintaining their proliferative activity. C_LI

molecular biology↗