[Effects of bombesin and its antibody on growth of human prostatic carcinoma cell lines].

Bombesin (BMBS), a tetradecapeptide isolated from frog skin, and its antibody were evaluated in vitro and in vivo for their growth modulating effects on human prostatic carcinoma cell lines DU-145 and PC-3. The two cell lines were maintained in DME medium containing 2% FCS and 1 microgram/ml insulin in a humidified atmosphere of 5% CO2/95% air at 37 degrees C. BMBS added at 0.1-10.0 nM caused a striking shift of the concentration-dependent increase in cell growth of DU-145 and PC-3 in the absence of any other exogenously added growth factors. The addition of 1:250 antibody versus BMBS (Ab-BMBS; rabbit antiserum) to the medium during the lag phase of growth resulted in specific inhibition of growth of DU-145 and PC-3 with or without BMBS. Nude mice were transplanted with DU-145 cells in order to evaluate the suppressing qualities of Ab-BMBS on carcinoma cells in vivo. After the inoculation of 10(7) cells/mouse DU-145 into nude mice, 20 microliters/mouse Ab-BMBS was intraperitoneally injected into mice three times weekly for three weeks. In mice administrated with Ab-BMBS, the growth of DU-145 was suppressed markedly. By immunocytochemical study, BMBS immunoreactivities were detected on DU-145 and PC-3 cells. These results suggest that BMBS can function as an autocrine growth factor for human prostatic carcinoma cells. Furthermore, on xenografts in mice, Ab-BMBS inhibits the increase of human prostatic carcinoma.