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Anticancer Res. 1991 May-Jun;11(3):1265-8.

Membrane transport of methotrexate in a squamous carcinoma cell line adapted to low folate concentrations.

Author information

1
Department of Otorhinolaryngology/Head and Neck Surgery, University Hospital Utrecht, The Netherlands.

Abstract

Membrane transport characteristics of the folate analogue methotrexate (MTX) were studied in a human squamous carcinoma cell line of the head and neck (HNSCC) adapted to grow in tissue culture media with nanomolar reduced folate concentrations (SCC-11B-LF), as compared to SCC-11B cells grown in standard medium containing high folate concentrations. We observed that SCC-11B-LF cells exhibited a 10.5-fold increased uptake of [3H]-MTX via the reduced folate/MTX carrier system compared to SCC-11B cells. Affinity labelling of the reduced folate/MTX carrier system suggests that the up-regulation of [3H]-MTX transport mainly results from an increased rate of carrier translocation, and only to a minor extent (15-20%) from an increased amount of carrier protein. The upregulation of MTX transport resulted in a 2.4-fold increased growth inhibitory effect by MTX. These results suggest that membrane transport may play a more important role in MTX-cytotoxicity when SCC-11B cells in vitro are grown in more physiological folate concentrations.

PMID:
1888158
[Indexed for MEDLINE]

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