Project: Research project

Project Details


This proposal is a continuum of investigative activities in this laboratory
which define the characteristics of the membrane transport of the antifols and
their interaction with target site(s) within the intact cell. These studies
explore basic and applied aspects of MTX (methotrexate) pharmacokinetics with a
current emphasis on developing a better understanding of the basis of the
efficacy of high-dose MTX regimens. Properties of the MTX-cell interaction will
be correlated with growth characteristics of mammalian cell populations in
culture emphasizing the critical role that free intracellular MTX plays in
achieving the biochemical and cytotoxic effects of this agent. The nature of
the energy-dependent processes which inhibit accumulation of free intracellular
MTX will be evaluated. The mechanism by which vincristine augments cellular
uptake of MTX and potentiates inhibition of DNA synthesis by MTX will be further
characterized. A role for polyglutamates of MTX as factors in MTX cytoxicity
will be evaluated as well as the cellular pharmocokinetics of these compounds as
well as diesters of MTX. The nature of the interaction between MTX and DHFR
(dihydrofolate reductase) within the cell will be explored. Studies will
evaluate whether the requirement for free intracellular MTX to inhibit
tetrahydrofolate synthesis may be related to a form of DHFR unassociated with
NADPH. The cellular pharmacokinetics of aminopterin will be studied to
determine whether there is a role for this agent in high-dose regimens with
folinic acid rescue. Finally, aspects of the transport of MTX and other folate
compounds will be evaluated including the nature of multiple transport routes
for these compounds, characteristics of MTX autoexchange, and the thermodynamics
of MTX transport with particular regard to the possibility of an exit pump for
MTX and other folate compounds. Other studies will further assess the role of cellular microtubules in
energy-dependent transport processes with the characterization of the mechanism
by which microtubular inhibitors reduce uphill transport of
alpha-aminoisobutyric acid in Ehrlich ascites tumor cells.
Effective start/end date6/1/765/31/86


  • Medicine(all)