Potential role of caspase-3 and -9 in arsenic trioxide-mediated apoptosis in PCI-1 head and neck cancer cells
| Autor: | Jae Boo Seol, Eun Shil Kim, Young Yiul Lee, Jung Mi Hyun, Byoung Kook Kim, Woo Hyun Park, Chul Won Jung |
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| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | International Journal of Oncology. |
| ISSN: | 1791-2423 1019-6439 |
| DOI: | 10.3892/ijo.18.2.249 |
| Popis: | Arsenic trioxide (As 2 O 3 ) has been shown to inhibit the proliferation of hematologic malignant cells. Previously, we reported that As 2 O 3 had an antitumoral effect in head and neck cancer. Here, we investigated the induction of apoptosis and its mechanism in PCI-I head and neck squamous carcinoma cells, after treatment with As 2 O 3 . Treatment with 2 μM of As 2 O 3 caused apoptosis in PCI-I cells following 3 days of exposure, which was detected by the annexin V-PI and DAPI staining methods. The cell death population was markedly increased, being 88% larger than the As 2 O 3 -untreated control cells. To address the mechanism of apoptosis, a Western blot assay was performed, showing that Bax was up-regulated without a change in Bcl-2. Activation of caspase-9 during As 2 O 3 -induced apoptosis was substantiated by monitoring the proteolysis of the caspase-9, which was associated with an increase of Apaf-1 and cytochrome c protein. PCI-1 cells rapidly changed the mitochondria membrane potential (Δψ m ) after addition of As 2 O 3 . Furthermore, activation of caspase-3 was demonstrated by monitoring the proteolysis of the caspase-3 and by measuring caspase-3 activity with a fluorogenic substrate, which was associated with the cleavage of poly(ADP-ribose) polymerase. To examine the in vivo effect of As 2 O 3 , C3H mouse inoculated with syngenic SCC7 cells was treated by intratumoral injection of As 2 O 3 (300 μg) every day, demonstrating that tumor mass was dramatically reduced on day 4, and revealed induction of apoptosis by TUNEL assay. These results suggest that apoptosis of PCI-1 cells by As 2 O 3 is induced by activation of caspase-3 via cytochrome c, caspase-9 and Apaf-I complex. |
| Databáze: | OpenAIRE |
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