Annexin II cell surface and mRNA expression in human acute myeloid leukaemia cell lines.
BACKGROUND
Acute promyelocytic leukaemia (APL) (M3) is associated with both a characteristic t(15;17) and severe bleeding diathesis caused by disseminated intravascular coagulation (DIC) and/or hyperfibrinolysis. It has been suggested that annexin II, a coreceptor for tissue plasminogen activator (t-PA) and plasminogen (PLG), is overexpressed on the surface of promyelocytes, leading to an increased fibrinolytic potential.


METHODS
This study examined the level of annexin II cell surface and mRNA expression in a range of acute myeloid leukaemia (AML) cell lines. The evidence that annexin II levels are higher in APL would lend support to the hypothesis that the bleeding disorder seen in APL is caused by hyperfibrinolysis.


RESULTS
Cell surface annexin II was found to be expressed at higher levels on NB4 (promyelocytic) cells than on either KG1a (early myeloid) or HL60 (myelocytic) cells. However, even higher levels were found on U937 and MM6 (histo-monocytic) and HEL (erythroid) cells (p<0.01). MM6 cells showed a threefold increase in annexin II mRNA compared to any of the other cell lines.


CONCLUSIONS
These findings do not fully support the concept of the coagulopathy associated with APL being caused by hyperfibrinolysis alone. Further investigations are required to identify the significance of annexin II expression and regulation in leukaemia.
Olwill
Shane A
SA
School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA Northern Ireland, UK. shane.olwill@fusionantibodies.com
McGlynn
Hugh
H
Gilmore
William S
WS
Alexander
H Denis
HD
D017306:Annexin A2 / Q000032:analysis / Q000235:genetics*; D045744:Cell Line, Tumor; D005342:Fibrinolysis; D015972:Gene Expression Regulation, Neoplastic; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D007951:Leukemia, Myeloid / Q000378:metabolism* / Q000473:pathology; D015473:Leukemia, Promyelocytic, Acute / Q000150:complications* / Q000378:metabolism; D008565:Membrane Proteins; D012333:RNA, Messenger / Q000032:analysis*
C472822:ANXA2 protein, human; D017306:Annexin A2; D008565:Membrane Proteins; D012333:RNA, Messenger