Bortezomib/proteasome inhibitor triggers both apoptosis and autophagy-dependent pathways in melanoma cells.
Generally, both endoplasmic reticulum (ER) stress and mitochondrial dysregulation are a potential therapeutic target of anticancer agents including bortezomib. The treatment of melanoma cells with bortezomib was found to induce apoptosis together with the upregulation of Noxa, Mcl-1, and HSP70 proteins, and the cleavage of LC3 and autophagic formation. Also, bortezomib induced ER-stress as evidenced by the increase of intracellular Ca(2+) release. In addition, bortezomib enhanced the phosphorylation of inositol-requiring transmembrane kinase and endonuclease 1α (IRE1α), apoptosis signal-regulating kinase 1 (ASK1), c-jun-N-terminal kinase (JNK) and p38, and the activation of the transcription factors AP-1, ATF-2, Ets-1, and HSF1. Bortezomib-induced mitochondrial dysregulation was associated with the accumulation of reactive oxygen species (ROS), the release of both apoptosis inducing factor (AIF) and cytochrome c, the activation of caspase-9 and caspase-3, and cleavage of Poly (ADP-ribose) polymerase (PARP). The pretreatment of melanoma cells with the inhibitor of caspase-3 (Ac-DEVD-CHO) was found to block bortezomib-induced apoptosis that subsequently led to the increase of autophagic formation. In contrast, the inhibition of ASK1 abrogated bortezomib-induced autophagic formation and increased apoptosis induction. Furthermore, the inhibition of JNK, of HSP70 also increased apoptosis induction without influence of bortezomib-induced autophagic formation. Based on the inhibitory experiments, the treatment with bortezomib triggers the activation of both ER-stress-associated pathways, namely IRE1α-ASK1-p38-ATF-2/ets-1-Mcl-1, and IRE1α-ASK1-JNK-AP-1/HSF1-HSP70 as well as mitochondrial dysregulation-associated pathways, namely ROS-ASK1-JNK-AP-1/HSF1-HS70, and AIF-caspase-3-PARP and Cyt.c, and caspase-9-caspase-3-PARP. Taken together, our data demonstrates for the first time the molecular mechanisms, whereby bortezomib triggers both apoptosis and autophagic formation in melanoma cells.
Institut National de la Santé et de la Recherche Médicale, U 977, France.
Denis
D
Selimovic
Benjamin B O W
BB
Porzig
Abdelouahid
A
El-Khattouti
Helene E
HE
Badura
Mutmid
M
Ahmad
Foued
F
Ghanjati
Simeon
S
Santourlidis
Youssef
Y
Haikel
Mohamed
M
Hassan
D000970:Antineoplastic Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D001897:Boronic Acids / Q000633:toxicity*; D000069286:Bortezomib; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3 / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D061988:Proteasome Inhibitors / Q000633:toxicity*; D050784:Proto-Oncogene Protein c-ets-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011719:Pyrazines / Q000633:toxicity*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D000970:Antineoplastic Agents; D001897:Boronic Acids; D018840:HSP70 Heat-Shock Proteins; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D061988:Proteasome Inhibitors; D050784:Proto-Oncogene Protein c-ets-1; D019253:Proto-Oncogene Proteins c-bcl-2; D011719:Pyrazines; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D000069286:Bortezomib; D048848:MAP Kinase Kinase Kinase 5; C482858:MAP3K5 protein, human; D053148:Caspase 3; D002118:Calcium