Production by K 562 cells of an inhibitor of adherence-related functions of human neutrophils.
Certain tumor cells generate factors that inhibit neutrophil chemotaxis. Our study was designed to explore whether such factors are produced by K 562 malignant cells and whether these have a broader effect in altering neutrophil functions. After 48 h of in vitro culture of K 562 cells, the culture medium and the cells were separated, lyophilized, and extracted with ethanol. These K 562 products, i.e., either the cell or supernatant extract, inhibited both nonstimulated locomotion and locomotion induced either by FMLP or activated serum. Furthermore, K 562 products inhibited neutrophil adherence and oxidative burst induced by opsonized zymosan, whereas oxidative burst induced by PMA or FMLP was not altered. K 562 products had an inhibitory effect on the PMN binding to iC3b-coated particles. They did not modify Mo1 expression of resting cells, did not alter the up-regulation of the receptor induced by FMLP but inhibited the FMLP-induced capping of Mo1 Ag. Con A capping was also inhibited. Actin polymerization in FMLP-stimulated PMN, as measured by flow cytometry and phalloidin binding to F-actin, was inhibited by K 562 products. The inhibitory factor present in K 562 products (cell and culture supernatant) was purified in three steps including gel filtration, ion-exchange chromatography, and IEF. The eluted active fraction corresponded to single band of about 8 kDa on SDS-PAGE. From these experiments, it is concluded that K 562 malignant cells in culture contain and release a low molecular mass factor (congruent to 8 kDa) that inhibits all adherence-related functions of neutrophils, whereas it does not alter FMLP- or PMA-induced oxidative burst. Further studies are needed to assess whether products of other tumor cells also act on the neutrophil by inhibiting adherence-related functions, Mo1 function and capping, and actin polymerization.
Amar
M
M
INSERM U. 294, Centre Hospitalo-Universitaire Xavier Bichat, Paris, France.
Amit
N
N
Huu
T P
TP
Chollet-Martin
S
S
Labro
M T
MT
Gougerot-Pocidalo
M A
MA
Hakim
J
J
D000199:Actins / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D002634:Chemotaxis, Leukocyte; D003208:Concanavalin A / Q000494:pharmacology; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000503:physiopathology*; D008970:Molecular Weight; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*; D010101:Oxygen Consumption; D010447:Peptide Hydrolases / Q000494:pharmacology; D011951:Receptors, Complement / Q000502:physiology; D011952:Receptors, Concanavalin A / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000199:Actins; D011951:Receptors, Complement; D011952:Receptors, Concanavalin A; D003208:Concanavalin A; D013481:Superoxides; D010447:Peptide Hydrolases