title: Involvement of ROS in chlorogenic acid-induced apoptosis of Bcr-Abl+ CML cells.
abstract: Chlorogenic acid (Chl) has been reported to possess a wide range of biological and pharmacological properties including induction of apoptosis of Bcr-Abl(+) chronic myeloid leukemia (CML) cell lines and clinical leukemia samples via inhibition of Bcr-Abl phosphorylation. Here we studied the mechanisms of action of Chl in greater detail. Chl treatment induced an early accumulation of intracellular reactive oxygen species (ROS) in Bcr-Abl(+) cells leading to downregulation of Bcr-Abl phosphorylation and apoptosis. Chl treatment upregulated death receptor DR5 and induced loss of mitochondrial membrane potential accompanied by release of cytochrome c from the mitochondria to the cytosol. Pharmacological inhibition of caspase-8 partially inhibited apoptosis, whereas caspase-9 and pan-caspase inhibitor almost completely blocked the killing. Knocking down DR5 using siRNA completely attenuated Chl-induced caspase-8 cleavage but partially inhibited apoptosis. Antioxidant NAC attenuated Chl-induced oxidative stress-mediated inhibition of Bcr-Abl phosphorylation, DR5 upregulation, caspase activation and CML cell death. Our data suggested the involvement of parallel death pathways that converged in mitochondria. The role of ROS in Chl-induced death was confirmed with primary leukemia cells from CML patients in vitro as well as in vivo in nude mice bearing K562 xenografts. Collectively, our results establish the role of ROS for Chl-mediated preferential killing of Bcr-Abl(+) cells.
authors.affiliation: Department of Infectious Diseases & Immunology, Indian Institute of Chemical Biology, A Unit of Council of Scientific and Industrial Research (CSIR), 4, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India.
authors.forename: Srabanti
authors.initials: S
authors.lastname: Rakshit
authors.forename: Labanya
authors.initials: L
authors.lastname: Mandal
authors.forename: Bikas Chandra
authors.initials: BC
authors.lastname: Pal
authors.forename: Jayashree
authors.initials: J
authors.lastname: Bagchi
authors.forename: Nabendu
authors.initials: N
authors.lastname: Biswas
authors.forename: Jaydeep
authors.initials: J
authors.lastname: Chaudhuri
authors.forename: Avik Acharya
authors.initials: AA
authors.lastname: Chowdhury
authors.forename: Anirban
authors.initials: A
authors.lastname: Manna
authors.forename: Utpal
authors.initials: U
authors.lastname: Chaudhuri
authors.forename: Aditya
authors.initials: A
authors.lastname: Konar
authors.forename: Tulika
authors.initials: T
authors.lastname: Mukherjee
authors.forename: Parasuraman
authors.initials: P
authors.lastname: Jaisankar
authors.forename: Santu
authors.initials: S
authors.lastname: Bandyopadhyay
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002726:Chlorogenic Acid / Q000302:isolation & purification / Q000494:pharmacology*; D016044:Fusion Proteins, bcr-abl / Q000096:biosynthesis* / Q000502:physiology; D055785:Gene Knockdown Techniques / Q000379:methods; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D031721:Piper betle; D018515:Plant Leaves; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D020298:U937 Cells; D023041:Xenograft Model Antitumor Assays / Q000379:methods
chemical_list: D017382:Reactive Oxygen Species; D002726:Chlorogenic Acid; D016044:Fusion Proteins, bcr-abl