Essential role of the voltage-dependent anion channel (VDAC) in mitochondrial permeability transition pore opening and cytochrome c release induced by arsenic trioxide

Abstract

The precise molecular mechanism underlying arsenic trioxide (As 2 O 3 )-induced apoptosis is a subject of extensive study. Here, we show that clinically relevant doses of As 2 O 3 can induce typical apoptosis in IM-9, a multiple myeloma cell line, in a Bcl-2 inhibitable manner. We confirmed that As 2 O 3 directly induced cytochrome c (cyto c) release from isolated mouse liver mitochondria via the mitochondrial permeability transition pore, and we further identified the voltage-dependent anion channel (VDAC) as a biological target of As 2 O 3 responsible for eliciting cyto c release in apoptosis. First, pretreatment of the isolated mitochondria with an anti-VDAC antibody specifically prevented As 2 O 3 -induced cyto c release. Second, in proteoliposome experiments, VDAC by itself was sufficient to mediate As 2 O 3 -induced cyto c release, which could be specifically inhibited by Bcl-X L . Third, As 2 O 3 induced mitochondria membrane potential (DWm) reduction and cyto c release only in the VDAC-expressing, but not in the VDAC-deficient yeast strain. Finally, we found that As 2 O 3 induced the increased expression and homodimerization of VDAC in IM-9 cells, but not in Bcl-2 overexpressing cells, suggesting that VDAC homodimerization could potentially determine its gating capacity to cyto c, and Bcl-2 blockage of VDAC homodimerization represents a novel mechanism for its inhibition of apoptosis.

The role of Akt on Arsenic trioxide suppression of 3T3-L1 preadipocyte differentiation

“…This could be due to the induction of differentiation at lower dose or induction of apoptosis or autophagic cell death at higher dose [7]. Others and we have reported that arsenic at clinically achievable dosage induced apoptosis by activating mitochondrial dependent apoptosis [8,9]. It is not surprising that arsenic trioxide could disrupt multiple signaling pathways for mitogenesis, differentiation, apoptosis and cell cycle control [10,11].…”

“…After that, cells were stained with 25 ng/mL Annexin V-FITC at 37ºC for 10min, and stained with PI just before detection. Then Annexin-V positive apoptotic cells was determined by a BD FACScan as previously described [8].…”

The voltage-dependent anion channel-1 modulates apoptotic cell death

“…Support for involvement of VDAC oligomerization in apoptosis is presented in recent studies on the reagent As 2 O 3 , where its apoptosis-inducing effect was attributed to an induction of homodimerization of VDAC molecules. 40 This effect could be prevented by overexpression of the antiapoptotic protein Bcl-xL. 40 The relationship between VDAC overexpressioninduced apoptosis and VDAC oligomerization requires additional study, including direct monitoring of the oligomerization process in live cells, both in control cells and cells overexpressing VDAC.…”

“…40 This effect could be prevented by overexpression of the antiapoptotic protein Bcl-xL. 40 The relationship between VDAC overexpressioninduced apoptosis and VDAC oligomerization requires additional study, including direct monitoring of the oligomerization process in live cells, both in control cells and cells overexpressing VDAC.…”

Weight of evidence evaluation of a network of adverse outcome pathways linking activation of the nicotinic acetylcholine receptor in honey bees to colony death

“…In addition to the role mitochondria play in ATP production, they mediate apoptosis via Ca 2+ accumulation through the voltage dependent anion-selective channel, activation of intra-mitochondrial protein kinases, and release of cytochrome c through the mitochondria permeability transition pore with further activation of caspases (Zheng et al, 2004;Green and Reed, 1998). With the identification of nAChR on the outer mitochondrial membrane in mammals, ongoing studies have Fig.…”