Effect of glycosylphosphatidylinositol specific phospholipase D gene expression levels on complement mediated killing of leukemic cells in patients with chronic myeloid leukemia.
BACKGROUND
To explore the disparity in glycosylphosphatidylinositol phospholipase D (GPI-PLD) expression levels between mononuclear cells of chronic myeloid leukemia (CML) and healthy controls, and clarify the certain relation of GPI-PLD expression levels to complement mediated killing of leukemic cells.


METHODS
Competitive RT-PCR was used to detect quantitatively the GPI-PLD mRNA in mononuclear cells. GPI-anchored CD55 and CD59 were analyzed by flow cytometry and Western blotting. Complement-mediated lysis was assessed by staining method of trypan blue dye.


RESULTS
The GPI-PLD activities and their mRNA copies in CML patients were significantly lower than those in healthy adults. At the tenth day after treatment with bone marrow transplantation (BMT), the GPI-PLD activities and copies of GPI-PLD mRNA almost recovered to the expression levels of healthy subjects. The expression of both CD55 and CD59 in CML patients were significantly higher than those in healthy subjects. After treatment with insulin (10(-7) mol/l) plus glucose (16.7 mmol/l) for 48 h, the cellular GPI-PLD activity and mRNA levels in K562 cells derived from the leukemic cells of a CML patient all increased about 3-fold. Simultaneously, the GPI-anchored CD55 and CD59 on cell surfaces were released into the culturing medium, and the killing rate of complement-mediated K562 cell lysis increased almost 3 times.


CONCLUSIONS
The decreased GPI-PLD expression may reduce the release of GPI-anchored CD55 and CD59 in leukemia cells and finally decrease complement mediated killing of these cells in chronic phase of CML.
Jian-Hua
Tang
T
Department of Biochemistry, Institute of Biological Science and Technology, Central South University, Xiangya Road 88, Mail box 54number, Changsha, Hunan 410078, PR China. miket561@xysm.net
Xiao-Jie
Zhang
Z
Yi-Dan
Wang
W
Wen-Kai
Li
L
Wang-Jiao
He
H
Cheng-Hong
Wang
W
Gui-Yuan
Li
L
D000328:Adult; D001483:Base Sequence; D015153:Blotting, Western; D018958:CD55 Antigens / Q000378:metabolism; D018957:CD59 Antigens / Q000378:metabolism; D016022:Case-Control Studies; D016923:Cell Death / Q000502:physiology*; D003165:Complement System Proteins / Q000502:physiology*; D017931:DNA Primers; D005434:Flow Cytometry; D015870:Gene Expression; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000201:enzymology / Q000473:pathology*; D010739:Phospholipase D / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018958:CD55 Antigens; D018957:CD59 Antigens; D017931:DNA Primers; D017261:Glycosylphosphatidylinositols; D012333:RNA, Messenger; D003165:Complement System Proteins; D010739:Phospholipase D