Repeated treatment with subtoxic doses of TRAIL induces resistance to apoptosis through its death receptors in MDA-MB-231 breast cancer cells.
Recombinant human tumor necrosis factor-related apoptosis-inducing ligand (rhTRAIL) is being evaluated clinically in treating various malignancies. Previous studies have shown that repeated application of high doses of rhTRAIL results in a subpopulation of parental cells that is unresponsive to the death ligand. However, it is not clear whether TRAIL-sensitive cancer cells could acquire resistance to TRAIL treatment. Here, we found that MDA-MB-231 breast cancer cells, which are highly sensitive to TRAIL-induced apoptosis, became resistant to TRAIL killing after a prolonged exposure to subtoxic doses of rhTRAIL. The resulting TRAIL-resistant cells were cross-resistant to antibodies against its death receptors (DR4 and DR5); however, they retained sensitivity to several clinically relevant chemotherapies. Surface expression of DR4 and DR5 was significantly reduced in the selected cells, resulting in failure in death-inducing signaling complex formation and caspase activation. In addition, real-time PCR analysis revealed an upregulation in multiple apoptosis-regulator genes, including c-FLIP, Stat5a, and Stat5b. Inhibition of Janus-activated kinase, an upstream activator of signal transducer and activator of transcription 5 (Stat5), or knockdown of Stat5 itself partially restored cellular sensitivity to TRAIL-induced apoptosis, suggesting that Stat5 signaling is also involved in the development of TRAIL resistance. Furthermore, we showed that acquired TRAIL resistance was effectively eliminated by combination with etoposide, doxorubicin, or paclitaxel. These results suggest that tumor cells could acquire resistance to TRAIL therapy especially when they are repeatedly exposed to low levels of the death ligand, highlighting the necessity of combination with therapies that target the resistance mechanisms.
Division of Therapeutic Proteins, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
Tatsushi
T
Yoshida
Yaqin
Y
Zhang
Leslie A
LA
Rivera Rosado
Baolin
B
Zhang
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D045744:Cell Line, Tumor; D015536:Down-Regulation; D004317:Doxorubicin / Q000008:administration & dosage; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D005047:Etoposide / Q000008:administration & dosage; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D017239:Paclitaxel / Q000008:administration & dosage; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D050799:STAT5 Transcription Factor / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*; D014162:Transfection
D000911:Antibodies, Monoclonal; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D050799:STAT5 Transcription Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505653:TNFSF10 protein, human; D005047:Etoposide; D004317:Doxorubicin; D017239:Paclitaxel