Castanospermine, an indolizidine alkaloid isolated from the seeds of the chestnuttree Castanospermumaustrale,has beenshownto prevent the normal glycosylationalPrOCessingof the v-fins-transformingglyco protein. v-fins-transformedcellsgrownin vitro in the presenceof castano

Castanospermine, an indolizidine alkaloid isolated from the seeds of the chestnuttree Castanospermumaustrale,has beenshownto prevent the normal glycosylationalPrOCessingof the v-fins-transformingglyco protein. v-fins-transformedcellsgrownin vitro in the presenceof castano spermine accumulate Immature forms of the glycoprotein that do not reach the cell surface. These treated cells revert to the normal phenotype. We havenowextendedthose studiesto an in riro tumorigenicitymodel in the node mouse using v-fins-transformed rat cells (SM-FRE) and dietary administration of castanospermine. Following tumor induction with s.c. injection of 10' SM-FRE cells, mice whose diet had been supplemented with 2.4 mg castanospermine/g food consumed approxi mately 0.84 mg castanospermine/g mouse/day.Furthermore, these mice had slower growingtumors that were 2.6 times smaller than tumors in controlgroupsat the terminationofthe experiment24 dayspostinjection. These results indicate that castanospermine is effective in slowing the growth of v-fins-transformed cells in vi,'o, suggestingthat this drug may offeran effectivetherapyagainstcertaintumors,includingsome arising from activated protooncogenesthat encodeglycoproteinssuch as growth factor receptors.