Time course of the efflux of Hoechst33342.

<p>Cells were incubated with 3 µM Hoechst33342 in the presence of 10 µM of α-adrenoceptor antagonists (100 nM for ergot alkaloids) for 60 min at 37°C, washed twice with ice-cold HBSS and incubated with warmed HBSS in the presence of 10 µM of α-adrenoceptor antagonists (100 nM for ergot alkaloids) for the desired times. ○, HeLa; •, HeLa/SN100; Δ, HeLa/SN100+10 µM α-adrenoceptor antagonists (100 nM for ergot alkaloids). Each point represents the mean ± S.E. (n = 3), and error bars are included in the symbols. * and ** p<0.05 and 0.01 significantly different from the HeLa/SN100 cells in the absence of α-adrenoceptor antagonists at the corresponding time points, respectively.</p

Chemical structure of α-adrenoceptor antagonists used.

<p>Chemical structure of α-adrenoceptor antagonists used.</p

IC₅₀ values for mitoxantrone in HeLa and HeLa/SN100 cells in the presence of α-adrenoceptor antagonists.

<p>Each value shows the mean ± S.E. (n = 4).</p><p>Relative sensitivity: the ratio of IC₅₀ values for mitoxantrone in the control divided by that in the groups treated with α-adrenoceptor antagonists.</p><p>*and**: significantly different from the respective control at <i>p</i><0.05 and <i>p</i><0.01, respectively.</p

Cellular distribution of Hoehst33342.

<p>HeLa and HeLa/SN100 cells were precultured for 48 h in a humidified atmosphere containing 5% CO₂ at 37°C. (A) HeLa and HeLa/SN100 cells were incubated with phenol red-free HBSS containing 3 µM of Hoechst33342, and images were acquired at 0 and 15 min. (B) The effects of α-adrenoceptor antagonists at 10 µM (except for ergot alkaloids at 100 nM) for 15 min were demonstrated in HeLa/SN100 cells.</p

Time course of accumulation of Hoechst33342.

<p>Cells were incubated with 3 µM Hoechst33342 in the absence (○) or presence of α-adrenoceptor antagonists (ergot alkaloids: ▴, 1 nM; ▪, 10 nM; ♦, 100 nM, other α-adrenoceptor antagonists: ▴, 0.1 µM; ▪, 1 µM; ♦, 10 µM) for the desired times at 37°C. Each point represents the mean ± S.E. (n = 3), and error bars are included in the symbols. * and ** p<0.05 and 0.01 significantly different from the control at the corresponding time points, respectively.</p

Cell cycle profile of HeLa/SN100 cells treated with mitoxantrone in the presence of α-adrenoceptor antagonists.

<p>HeLa/SN100 cells were incubated with mitoxantrone for 8 hours in the absence (Control) or presence of α-adrenoceptor antagonists before being stained with propidium iodide. DNA content was analyzed by flow-cytometry and the percentage of cells in each phase of the cell cycle was obtained by using the Modfit program.</p

Reversal Effects of Ca2+ Antagonists on Multidrug Resistance via Down-regulation of MDR1 mRNA

In previous reports, the effects of 12 Ca2+ antagonists on a multidrug resistanttransporter, P-glycoprotein/MDR1, were evaluated in terms of those onMDR1-mediated transport of [3H]digoxin and the sensitivity of vinblastine sulfate orpaclitaxel, and they were able to be classified into 4 subgroups based on their actions,as those with transport inhibition and sensitivity recovery, those with or withouttransport inhibition but marginal sensitivity recovery, and those without both. Inthis study, our previous findings were confirmed by the resistance against doxorubicinhydrochloride and daunorubicin hydrochloride, and by the recovery of [3H] vinblastinesulfate accumulation. Furthermore, it was found that the effects of 12 Ca2+antagonists on the sensitivity recovery were also explained by the down-regulation ofMDR1 mRNA, suggesting a novel mechanism to reverse the MDR1-mediatedmultidrug resistance

CT images used.

We evaluated the accuracy of prediction using 25% partial CT images that contain lesion areas cropped from the vertical center 50% and horizontally left or right 50%.</p