The aim of our study was to develop a method for
selection of subpopulations of insulin producing
RINm cells with higher resistance to beta cell toxins.
Cells, resistant to streptozotocin (RINmS) and
alloxan (RINmA), were obtained by repeated exposure
of parental RINm cells to these two toxins,
while the defense capacity, was estimated by the
MTT colorimetric method, and [H3]-thymidine incorporation
assay. We found that RINmS and
RINmA displayed higher resistance to both streptozotocin
(STZ) and alloxan (AL) when compared to
the parental RINm cells. In contrast, no differences
in sensitivity to hydrogen peroxide were found
between toxin selected and parental cells. Partial
protection from the toxic effect of STZ and AL was
obtained only in the parental RINm cells after
preincubation of cells with the unmetabolizable 3-
O-methyl-glucose. The possibility that GLUT-2 is
involved in cell sensitivity to toxins was confirmed
by Western blot analysis, which showed higher
expression of GLUT-2 in parental RINm compared
to RINmS and RINmA cells. In addition to the
higher cell defense property evidenced in the
selected cells, we also found higher insulin content
and insulin secretion in both RINmS and RINmA
cells when compared to the parental RINm cells. In
conclusion, STZ and AL treatment can be used for
selection of cell sub-populations with higher cell defense properties and hormone production. The
different GLUT-2 expression in parental and re
sistant cells suggest involvement of GLUT-2 in
mechanisms of cell response to different toxins.
