INHIBITION OF TUMOR-CELL INVASION IN THE BOYDEN CHAMBER ASSAY BY A MANNOSIDASE INHIBITOR, MANNOSTATIN-A

An alpha-mannosidase inhibitor, mannostatin A, from Streptoverticilliu m verticillus var. quintum inhibited chemotactic invasion of mouse B16 /F10 melanoma cells in the Boyden chamber assay. It also inhibited in vitro invasion of K-ras-NIH3T3 cells. Mannostatin A did not inhibit th e growth of either cell line at the concentration effective to inhibit invasion. Addition of mannostatin A to the cultured B16/F10 or K-ras- NIH3T3 cells inhibited cellular alpha-mannoside activity specifically- Mannostatin A-treated B161Fd10 cells also showed decreased metastatic activity in vivo in C57Bl/6 mice.