The effect of methotrexate (MTX) on primary cultures of dimethylbenzenthracene (DMBA)-induced mammary tumors evaluated. Dose response curves and thymidine labelling indices from twelve tumors treated with 10-9 to 10-2M MTX varied considerably but showed three main patterns. At lower concentrations 10-9-10-8M, between 90-100% of cells survived 48 hours treatment. At 10-3M, only 50-60% of the cells remained. In 30% of the cultures, MTX was less toxic near saturation 10-2M than at 10-3M. This 'rebound' phenomenon was not observed in 60% of the cultures. The remaining 10% of tumors showed no response to MTX. Labelling index and cell survival correlated well in all experiments. As with cell kinetic data, a diversified ultrastructural response was also seen. Cultures exhibiting the 'rebound' phenomenon indistinguishable from controls. Compared with the sensitivity of different cell lines to MTX, DMBA-induced mammary tumor cells appear to be highly resistant to the drug.
|Original language||English (US)|
|Number of pages||2|
|Journal||IRCS Medical Science|
|State||Published - Jan 1 1981|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)