Effects of plasminogen, streptokinase and their equimolar complexes with pyruvate kinase on the human neuroblastoma IMR-32 cells

Abstract

The system of extracellular proteolysis consisted of plasminogen (PGn), its active protease, plasmin, and PGn activators and their inhibitors affect the growth, differentiation, and proliferation of nervous cells both under normal and pathological conditions. The purpose of our investigation was to study the effects of exogenous PGn, its activator, streptokinase (SK), pyruvate kinase (PK), and their equimolar complexes on morphological and functional properties of IMR-32 neuroblastoma cells. It has been found that PGn, SK, PK, and their complexes stimulate cell proliferation during 1–3 days of incubation. We also observed increased DNA, RNA, and protein content. The low-lactate dehydrogenase (LDH) efflux indicated that the addition of the proteins we assayed to the culture medium prevented the development of degenerative processes caused by serum deprivation. The levels of extracellular PGn-activator activity, as measured by the fibrinolytic method, increased in the presence of SK. The SK effect vanished if SK was in the complex with PK on the 3rd day of cultivation. New original facts were obtained to testify the probability of initiation of neoplastic transformation and tumor growth potentiation.