Effect of Spry2 in cisplatin cytotoxicity. A–C, the
PH3MT, PH3MT-2A3, and MSU1.1 cell strains were treated with cisplatin at a
concentration of 0, 2, 5, 10, 20, and 40 μm concentrate for 6 h,
allowed to grow under normal conditions for 24–48 h, and assayed for
cisplatin cytotoxicity as described under “Experimental
Procedures.” The number of cells is proportional to the optical density
at 490 nm (A490 nm). The -fold decrease in
A490 nm, relative to the untreated samples, is shown. For
each panel, a representative of three independent experiments (in each
n = 4) is shown. Where error bars are not shown, they are within the
data point. D, a public data set from a previous study measuring
genetic changes associated with cisplatin resistance in lung cancer was mined
to determine the association between Spry2 expression and increased cisplatin
IC50. Cell lines derived from patients with small cell
(SCLC), squamous cell (SqCLC), or non-small cell
(NSCLC) lung cancer were sorted according to their relative Spry2
expression. For each cell line, the expression of Spry2 and Akt is reported as
a dichotomous variable, i.e. either high (H) or low
(L), depending on whether the level of these genes in that cell line
was greater or less than their median expression in the entire subset. Each
circle represents a cell line, whereas the bar represents
the average IC50 for that group. A similar analysis was performed
for Akt expression.