American Society of Hematology

Fig. 8.

$Fig. 8. MM cells resistant to doxorubicin or melphalan retain full sensitivity to UCN-01/PD184352. / Logarithmically growing parental 8226 cells (8226/S; A), a doxorubicin-resistant cell line (8226/Dox40; B), and a melphalan-resistant line (8226/LR5; C) were exposed to 10 μM PD184352 + 150 nM UCN-01, 400 nM doxorubicin (Dox), or 5 μM melphalan (Mel) for 24 to 72 hours, after which the percentage of apoptotic cells was determined by examining Wright-Giemsa–stained cytospin preparations as described in “Materials and methods.” Values represent the means ± SD for 3 separate experiments performed in triplicate. (D) 8226/Dox40 and 8226/LR5 cells were exposed to PD184352 + UCN-01 as above for 48 hours and 24 hours, respectively, after which Western blot analysis was employed to monitor degradation of PARP into an 85-kDa fragment (CF) or release of cytochrome c and Smac/DIABLO into the cytosolic S-100 fraction as described above. Lanes were loaded with 30 μg of protein; blots were subsequently stripped and reprobed for expression of β actin to ensure equivalent loading and transfer of protein. The results of a representative experiment are shown; an additional study yielded equivalent results.$

MM cells resistant to doxorubicin or melphalan retain full sensitivity to UCN-01/PD184352.

Logarithmically growing parental 8226 cells (8226/S; A), a doxorubicin-resistant cell line (8226/Dox40; B), and a melphalan-resistant line (8226/LR5; C) were exposed to 10 μM PD184352 + 150 nM UCN-01, 400 nM doxorubicin (Dox), or 5 μM melphalan (Mel) for 24 to 72 hours, after which the percentage of apoptotic cells was determined by examining Wright-Giemsa–stained cytospin preparations as described in “Materials and methods.” Values represent the means ± SD for 3 separate experiments performed in triplicate. (D) 8226/Dox40 and 8226/LR5 cells were exposed to PD184352 + UCN-01 as above for 48 hours and 24 hours, respectively, after which Western blot analysis was employed to monitor degradation of PARP into an 85-kDa fragment (CF) or release of cytochrome c and Smac/DIABLO into the cytosolic S-100 fraction as described above. Lanes were loaded with 30 μg of protein; blots were subsequently stripped and reprobed for expression of β actin to ensure equivalent loading and transfer of protein. The results of a representative experiment are shown; an additional study yielded equivalent results.

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