Vitamin K2 induces apoptosis of a novel cell line established from a patient with myelodysplastic syndrome in blastic transformation.
We have previously reported that vitamin K2 (VK2) has a potent apoptosis inducing activity toward various types of primary cultured leukemia cells including acute myelogenous leukemia arising from myelodysplastic syndromes (MDS). We established a novel cell line, designated MDS-KZ, from a patient with MDS in blastic transformation, and further investigated the effects of VK2 using this novel cell line. MDS-KZ shows complex chromosomal anomaly including -4, 5q-, -7, 13q+, 20q-, consistent with that seen in the original patient. Culture of MDS-KZ cells in RPMI1640 medium containing 10% FBS lead to steady but very slow proliferation with a doubling time of 14 days. However, the cellular growth rate was significantly accelerated in the presence of various growth factors such as granulocyte colony-stimulating factor, stem cell factor, granulocyte-macrophage colony-stimulating factor, interleukin-3, and thrombopoietin. Most of the cultured cells show the morphological features of myeloblasts. They are positive for CD7, CD33, CD34, CD45, CD117, and HLA-DR. However, about 10% of the cells are more mature metamyelocytes and neutrophils with various dysplastic characteristics such as pseudo-Pelger nuclear anomaly and hypersegmentation, suggesting a potential for differentiation in this cell line. As previously reported for cultured primary leukemia cells, exposure to VK2, but not to VK1, resulted in induction of apoptosis of MDS-KZ cells in a dose-dependent manner (IC50: 5 microM). In addition, VK2 treatment induced down-regulation of BCL-2 and up-regulation of BAX protein expression with concomitant activation of caspase-3 (CPP32). A tetrapeptide functioning as antagonist of caspase-3, Ac-DEVD-H, suppressed the VK2-induced inhibition of cell growth, suggesting that caspase-3 is, at least in part, involved in VK2-induced apoptosis. These observations suggest that the MDS-KZ cell line can serve as a model for the study of the molecular mechanisms of VK2-induced apoptosis.
Nishimaki
J
J
First Department of Internal Medicine (Hematology/Oncology), Tokyo Medical University, Japan.
Miyazawa
K
K
Yaguchi
M
M
Katagiri
T
T
Kawanishi
Y
Y
Toyama
K
K
Ohyashiki
K
K
Hashimoto
S
S
Nakaya
K
K
Takiguchi
T
T
D000368:Aged; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002461:Cell Line, Transformed; D016207:Cytokines / Q000494:pharmacology; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D009190:Myelodysplastic Syndromes / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D014812:Vitamin K / Q000627:therapeutic use*
D016207:Cytokines; D014812:Vitamin K; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases