T. Harrach et al., BROMELAIN PROTEINASES MODULATE THE CD44 EXPRESSION ON HUMAN MOLT-4 8 LEUKEMIA AND SK-MEL-28 MELANOMA-CELLS IN-VITRO/, International journal of oncology, 5(3), 1994, pp. 485-488
CD44 cell surface proteins are involved in leukocyte binding to endoth
elium and the metastatic spread of tumor cells. Using flow cytometric
analysis (FCMA), we investigated the effects of the proteases bromelai
n, papain, trypsin, and chymotrypsin on the density of CD44 molecules
present on human leukemia Molt 4/8 cells. Bromelain was found to be mo
st active in reducing CD44 receptor density. In addition, the effects
of the purified bromelain proteinases F4 and F9 were investigated. On
Molt 4/8 cells crude bromelain and F9, with the highest proteolytical
activity, were found to be most active in reducing CD44 receptor densi
ty with a half maximal value of 1.9 mu g/ml and 2.3 mu g/ml, respectiv
ely. On human SK-Mel 28 melanoma cells especially F9 showed a strong e
ffect, with a half maximal value of 1.5 mu g/ml. The implications of t
he findings are discussed with view of the reported antimetastatic act
ivity of orally administrated bromelain with respect to CD44.