The Effects of Increased Expression of DLK1 Gene on the Pathogenesis of Myelodysplastic Syndromes

Delta-like-1 (DLK1) is frequently expressed at elevated levels in CD34+ cells from patients with MDS. To investigate its role in the pathogenesis of MDS, we tested bone marrow samples from a panel of patients with MDS, AML, or myeloproliferative neoplasms, with real-time polymerase chain reaction (PCR). We show here that DLK1 mRNA levels are higher in MDS patients and lower in AML patients than in healthy individuals. Myeloid progenitor 32D cells overexpressing DLK1 display increased apoptosis, reduced differentiation, and decreased cell number expansion, which is also accompanied by changes in cell cycle progression. Immortalized fibroblastic 3T3 cells can grow into tumors in nude mice but the size of tumors are smaller from those overexpressing DLK1. These observations suggest that DLK1 dysfunction may contribute to the ineffective hematopoiesis of MDS.