ANTITUMOR ACTION OF BOVINE SEMINAL RIBONUCLEASE

Unlike the bovine pancreatic ribonuclease (RNaseA), bovine seminal rib onuclease (BS RNase) displays various biological activities, including antitumor activity, immunosuppressivity, spermatogenicity and embryot oxicity. To learn more about its antitumor effect we tested BS RNase o n the growth of 16 cell lines derived from patients with various hemat ological malignancies. The cells of lymphoid origin were generally mor e susceptible to BS RNase, administered in the range of concentrations from 2 to 100 mu g/ml, than the myeloid ones. RNaseA used at the same concentrations did not exert any inhibitory effect. The inhibitory ef fect of BS RNase persisted in cultured cells after three times wash in complete medium and cell recultivation in fresh medium free of BS RNa se. Four cell lines were very little sensitive (KG-1 and U-937) or res istant (JOK and NAMALWA) to BS RNase regardless of their origin. The i n vivo antitumor effect of BS RNase was tested on human prostate carci noma transplanted to athymic nude mice. The daily dose of BS RNase (0. 25 mg/20 g) was administered for three weeks except weekends (15 doses ) by three different ways (intraperitoneally - i.p., subcutaneously - s.c. and intratumorally - i.t.). Whereas i.p. administration was ineff ective, s.c. administration significantly reduced size of the tumors a nd i.t. administration abolished half of the tumors in treated mice. T he average weight of treated mice decreased during the experiment by 1 0-15%.