Antimetastatic action of polyactin A and its mechanism
Qiang, W.A.; Liu, J.R.; Wang, Y.S.; Lei, Y.D.
Yao Xue Xue Bao 29(5): 340-345
1994
ISSN/ISBN: 0513-4870 PMID: 7976351 Document Number: 434418
Polyactin A (PAA) is a home-made immunomodulator, isolated from submerged culture broths of alpha-hemolytic streptococci. The effect of PAA on the metastasis of B-16-F-10 melanoma cells in the syngeneic C-57BL/6J mice and its antimetastatic mechanism have been studied. The results showed that: PAA inhibited the experimental pulmonary metastasis nodules at a dose of 100 mg cntdot kg-1 cntdot d-1 for 18 d. The number of pulmonary metastasis nodules were significantly decreased from 137 to 95 as compared with those in the control. The plasma concentration of TXB-2 in B-16 bearing mice was higher than that in normal mice. After treatment with PAA, a decreased content of TXB-2 and 6-keto-PGF-1alpha was found without change of the ratio TXB-2 to 6-keto-PGF-1alpha. The cellular immunities were evidently decreased in the B-16 bearing mice. The restoration of lymphocyte proliferation response and augmentation of the NK cell activity of the splenocytes were found in vivo in normal mice and B-16 bearing mice after treated with PAA. PAA was also shown to antagonize the suppressing effect of cyclophosphamide on murine NK cells; PAA at the concentration of 10 apprx 5000 mu-g cntdot ml-1 was found to inhibit the biosynthesis of DNA, RNA and protein in the B-16-F-10 melanoma cells to different degrees and the effect was dose-dependent. It is evident that PAA is effective in preventing the pulmonary metastasis of B-16-F-10 melanoma, and the antimetastatic action may be related not only to promoting the effect the antitumor immunities, but also to inhibiting the growth of B-16-F-10 melanoma cells.