Methotrexate-gelonin conjugate - an inhibitor of MCF-7 cells expressing the dihydrofolate receptor

作者：Badr Mohamed; Kopp Christian; Theison Sandra; Meyer Jennifer; Trommer Wolfgang E^*

来源：Biological Chemistry, 2014, 395(12): 1461-1466.

DOI：10.1515/hsz-2013-0270

• comet assay
• immunotoxin
• methotrexate
• ribosome-inactivating proteins (RIPs)
• in vitro translation assay

An immunotoxin composed of gelonin, a basic ribosome-inactivating protein, type I of 30 kDa, isolated from the seeds of the Indian plant Gelonium multiflorum and methotrexate (MTX) has been studied as a potential tool of gelonin delivery into the cytoplasm of MTX-responsive cells. On the average, about five molecules of methotrexate were chemically coupled to gelonin via an N-hydroxysuccinimide ester of the drug. The MTX-gelonin conjugate was able to reduce the viability of MCF-7 cells in a dose-dependent manner with ID50 of 10 nm, whereas gelonin or MTX alone showed none or very little effects. Besides its ribosome-inactivating activity, which is about ten-fold lower in an in vitro translation assay (IC50 of 50.5 ng/ml as compared to 4.6 ng/ml), the conjugate also significantly induced direct and oxidative DNA damage as shown by the alkaline comet assay. Hence, MTX-gelonin conjugates are promising candidates for the treatment of MTX-responsive cancers.

• 出版日期2014-12