CMK Cells

The CMK cell line is a human megakaryoblastic leukemia model established from a Down syndrome patient diagnosed with acute megakaryoblastic leukemia (AMKL). These cells are significant for research on megakaryocytic differentiation and leukemia associated with trisomy 21. CMK cells display markers typical of megakaryocytes, such as glycoproteins GPIIb/IIIa and GPIb, which are key components of platelet membranes. The presence of platelet peroxidase (PPO) activity, localized to the nuclear envelope and endoplasmic reticulum but not the Golgi apparatus, confirms the megakaryocytic lineage of these cells. Ultrastructural analysis reveals the existence of cytoplasmic granules resembling α-granules and demarcation membranes, further validating their megakaryocytic nature.

CMK cells are characterized by a complex karyotype, including near-tetraploidy and a specific translocation, der(17)t(11;17), also present in the patient’s original leukemic cells. This genetic alteration links the cell line back to the disease state in the patient, providing a reliable model for studying AMKL pathogenesis. Additionally, the CMK cell line can respond to hematopoietic growth factors like interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), which stimulate proliferation and differentiation into more mature megakaryocytic forms. Treatment with agents like phorbol ester (TPA) enhances the expression of megakaryocytic markers and induces morphological changes, including cytoplasmic segmentation resembling platelet formation. These features make CMK a valuable tool for investigating megakaryocytic lineage development, the effects of trisomy 21 on hematopoiesis, and the mechanisms of leukemogenesis in Down syndrome.