MDS-L Cells

MDS-L is a human myelodysplastic syndrome (MDS)-derived cell line originally established from the MDS92 cell line, which itself was derived from the bone marrow of a patient with MDS exhibiting a del(5q) chromosomal abnormality. While MDS92 contained a heterogeneous mix of myeloid cells at varying stages of differentiation, MDS-L represents a blastic subline with more uniform features characteristic of immature myeloid progenitor cells. MDS-L retains interleukin-3 (IL-3) dependency for proliferation in vitro, mirroring the cytokine sensitivity seen in primary MDS progenitor cells. The line harbors multiple genetic alterations, including homozygous TP53 mutations and additional acquired mutations in NRAS and CEBPA. These alterations collectively reflect the clonal evolution and leukemic transformation potential typical of high-risk MDS.

MDS-L has been widely used as a model to investigate the molecular mechanisms underlying MDS pathogenesis, differentiation block, and therapeutic resistance. One significant finding using MDS-L was the demonstration that forced expression of granulocyte colony-stimulating factor receptor (G-CSFR) via retroviral transduction enabled granulocytic differentiation upon G-CSF stimulation. This was evidenced by morphological changes, increased CD11b expression, and enhanced nitroblue tetrazolium (NBT) reduction activity-indicative of terminal granulocyte maturation. These results revealed the intrinsic capacity of MDS-L to differentiate if the appropriate signaling components are restored, offering insights into potential gene therapy approaches targeting differentiation defects in MDS.

In addition to genetic and functional studies, MDS-L has been instrumental in characterizing the role of histone modifications in disease progression. Notably, the histone H3-K27M mutation, commonly associated with pediatric gliomas but rare in hematologic malignancies, was identified in MDS-L and found to inhibit EZH2-mediated histone methylation. This epigenetic alteration led to widespread reduction in H3-K27 methylation and was linked to altered expression of tumor suppressor genes such as p16. MDS-L sublines with or without this mutation-derived through differential IL-3 culture conditions-have further allowed exploration of epigenetic heterogeneity within MDS and its implications for IL-3-dependent growth and therapeutic response. These unique properties make MDS-L a powerful in vitro and in vivo model for studying the molecular evolution and therapeutic targeting of MDS and its transformation into acute myeloid leukemia.