Bovine seminal ribonuclease attached to nanoparticles made of polylactic acid kills leukemia and lymphoma cell lines in vitro

Bovine seminal ribonuclease (BS-RNase) is a protein with a number of biolog ical effects. It shows antitumoral, aspermatogenic, antiembryonic, immunosu ppressive and antiviral properties. The cytotoxic effects appear to be spec ific for tumor cells as non-malignant cells seem to be unaffected in vitro. Unfortunately, the in vivo application of BS-RNase so far was successful o nly when it was administered intratumorally. Therefore, the objective of th e present investigation was to improve the properties of BS-RNase by attach ment to nanoparticles made of polylactic acid (PLA-NP) using an adsorption method. This preparation was tested in vitro against leukemia (MOLT-4) and lymphoma (H9) cell lines sensitive and resistant to cytarabine. No differen ce between the nanoparticle preparation and pure BS-RNase was found in thes e tests, To examine the in vivo effects, the preparations were tested for t heir aspermatogenic and antiembryonal efficacy compared to the pure BS-RNas e as a rapid test for antitumoral activity. The aspermatogenic and antiembr yonal effects were enhanced by the nanoparticle preparation, Consequently, BS-RNase loaded adsorptively to PLA-NP holds promise for the in vivo use as an antitumoral agent. Further research will investigate the efficacy of th is preparations in an in vivo tumor model. [(C) 2000 Lippincott Williams & Wilkins.].