Autologous Bone Marrow Transplantation - Blog Science Connections

Pharmacological Manipulation and Purging 181
seen with vincristine alone (Fig 2) (22). These results suggest that the strategy
of employing verapamil to circumvent resistance to vincristine, and possibly
other drugs associated with the multiple-resistance phenotype, during in vitro
purging can be attempted without significant risk to normal hematopoietic
stem cells. Yalowich et al. (21), who also found that short exposures to
verapamil did not enhance vincristine's toxicity against CFCJ-QM cells, reported
enhanced toxicity of etoposide against CFCI-GM cells.
Selective Protection of Normal Stem Cells
We have previously shown that the cytotoxicity of nucleoside analogues
depends on the presence of a functional nucleoside transporter in the
COLONIES, % SURVIVED
CFU-GM
I 10 100
VINCRISTINE, MM
Figure 2. Effects of vincristine alone ('solid circles; and with 5 uM (open circles;, 10 uM
(solid triangles;, and 20 uM (open squares; verapamil on CFU-GM, BFU-E, and CFU-
GEMM colony formation (mean values of five to ten experiments). Differences in values
for vincristine with and without verapamil are not statistically significant.