PT  - JOURNAL ARTICLE
AU  - Hong Ke
AU  - Yiyu Wang
AU  - Dongming Ren
AU  - Lei Wang
TI  - Adriamycin Sensitizes Adriamycin-Resistant HL-60/ADR Cells to TRAIL-Mediated Apoptosis
AID  - 10.1007/s11805-008-0354-2
DP  - 2008 Oct 01
TA  - Chinese Journal of Clinical Oncology
PG  - 354--360
VI  - 5
IP  - 5
4099  - http://www.cancerbiomed.org/content/5/5/354.short
4100  - http://www.cancerbiomed.org/content/5/5/354.full
SO  - Cancer Biol Med2008 Oct 01; 5
AB  - OBJECTIVE To study whether an adriamycin-resistant cell line (HL-60/ADR) can be sensitized by adriamycin (ADR) to TRAIL-mediated apoptosis.METHODS The mRNA levels of the TRAIL receptor and apoptosis-related signaling molecules involved in the TRAIL-mediated apoptotic pathway were measured by RT-PCR. The protein levels of apoptotic-related signaling molecules involved in the TRAIL-mediated apoptotic pathway and processed caspase-3, caspase-9, and caspase-8 were measured by Western blots. Apoptosis was assessed by flow cytometry. Mitochondrial membrane potential was analyzed by DiOC6(3) staining. Cytotoxicity was determined by the colorimetric MTT viability/proliferation assay.RESULTS Treatment with a combination of TRAIL and subtoxic concentrations of ADR resulted in synergistic cytotoxicity and apoptosis for both the parental HL-60 and the HL-60/ADR cells. For HL-60, there was a 5-fold potentiation and synergy in cytotoxicity for TRAIL and for HL-60/ADR, cytotoxicity to TRAIL was potentiated 6-fold with ADR. Adriamycin treatment modestly up-regulated TRAIL-R2 (DR5), but had no effect on the expression of Fas-associated death domain, c-FLIP, Bcl-2, Bcl-xL, Bax, and IAP family members (cIAP-1, cIAP-2, XIAP, and survivin). The protein levels of pro-caspase-8 and pro-caspase-3 were not affected by ADR, whereas pro-caspase-9 and Apaf-1 were up-regulated. Combined treatment with TRAIL and ADR resulted in activation of caspase-9 and caspase-3, but there was no detectable processing of caspase-8 beyond the background levels. There was significant depolarization of the mitochondrial membrane by the combined treatment of both cell lines and it was more pronounced in the parental HL-60 cell line. The combined treatment with TRAIL and ADR resulted in 42.6% of the HL-60/ADR cells undergoing DNA fragmentation, whereas treatment with either ADR or TRAIL alone resulted in 5.46% and 21.3% DNA fragmented cells, respectively. Similar results were obtained with the HL-60 cells.CONCLUSION These findings demonstrate that ADR can still signal ADR-resistant tumor cells, resulting in the modification of the TRAIL-mediated signaling pathway and apoptosis.