Effects of serine protease and deoxyribonuclease on intravascular tumor cell arrest in rat blood-borne lung metastasis.

Effects of alpha-chymotrypsin and deoxyribonuclease I (DNase I) on the early phase of blood-borne lung metastasis in rats were studied using confocal laser scanning microscopy and AH-109A cells labeled either with carboxyfluorescein diacetate succinimyl ester or with 51Cr. Intravenous administration of alpha-chymotrypsin or DNase I appeared to enhance or inhibit, respectively, the tumor cell arrest in lung microvasculature as a reflection of reduction or promotion of the tumor cell clearance in the microvasculature. These results suggest that the effects of alpha-chymotrypsin and DNase I are related to induction of tumor cell aggregation and disaggregation in the blood stream, respectively.