Adenine nucleotide translocator mediates the mitochondrial membrane permeabilization induced by lonidamine, arsenite and CD437

Abstract

An increasing number of experimental chemotherapeutic agents induce apoptosis by directly triggering mitochondrial membrane permeabilization (MMP). Here we examined MMP induced by lonidamine, arsenite, and the retinoid derivative CD437. Cells overexpressing the cytomegalovirus-encoded protein vMIA, a protein which interacts with the adenine nucleotide translocator, were strongly protected against the MMP-inducing and apoptogenic effects of lonidamine, arsenite, and CD437. In a cell-free system, lonidamine, arsenite, and CD437 induced the permeabilization of ANT proteoliposomes, yet had no effect on protein-free liposomes. The ANT-dependent membrane permeabilization was inhibited by the two ANT ligands ATP and ADP, as well as by recombinant Bcl-2 protein. Lonidamine, arsenite, and CD437, added to synthetic planar lipid bilayers containing ANT, elicited ANT channel activities with clearly distinct conductance levels of 20+/-7, 100+/-30, and 47+/-7 pS, respectively. Altering the ATP/ADP gradient built up on the inner mitochondrial membrane by inhibition of glycolysis and/or oxidative phosphorylation differentially modulated the cytocidal potential of lonidamine, arsenite, and CD437. Inhibition of F(0)F(1)ATPase without glycolysis inhibition sensitized to lonidamine-induced cell death. In contrast, only the combined inhibition of glycolysis plus F(0)F(1)ATPase sensitized to arsenite-induced cell death. No sensitization to cell death induction by CD437 was achieved by glucose depletion and/or oligomycin addition. These results indicate that ANT is a target of lonidamine, arsenite, and CD437 and unravel an unexpected heterogeneity in the mode of action of these three compounds.

Mitochondria as therapeutic targets for cancer chemotherapy

“…A number of different agents are able to permeabilize ANT-containing proteoliposomes, but not plain liposomes, suggesting that they might be used to specifically permeabilize mitochondrial membranes. These include cytotoxic drugs such as lonidamine, arsenite and 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphtalene carboxylic acid (CD437) (Belzacq et al, 2001a) as well as the aforementioned BaxBH3 peptide. (Vieira et al, 2002).…”

“…All these compounds induce channel formation when ANT is reconstituted into lipid bilayers, but it is not known whether they act directly on ANT or at the ANT/lipid interface. They are likely, however, to promote a conformational change in ANT, since ANT-containing proteoliposomes permeabilization can be suppressed by the natural ANT ligands ATP and ADP (Belzacq et al, 2001a). Lonidamine showed remarkable effects on benign prostate hypertrophy and is undergoing clinical trials for the treatment of malignant tumors.…”

“…These compounds include arsenite (which depletes glutathione), 2-methyl-1,4-naphthoquinone (menadione, which undergoes futile redox cycles on the respiratory chain), and thiol-crosslinking agents such as diazenedicarboxylic acid bis5N,N-dimethylamide (diamide), bismaleimidohexane (BMH) and dithiodipyridine (DTDP), which are able to overcome cytoprotection by Bcl-2 and to cause ANT thiols oxidation (Costantini et al, 2000). Arsenite, which permeabilizes purified mitochondria in vitro (Belzacq et al, 2001a;Larochette et al, 1999) has also pro-oxidant effects and is used nowadays for the routine treatment of acute promyelomonocytic leukemia (Kroemer and de The´, 1999). The organic arsenic chemical 4-(N-(S-glutathionylacetyl)amino)phenylarsenoxide (GSAO) directly affects mitochondria, where it crosslinks the matrix-facing thiols of Cys-160 and Cys-257 of ANT, thus causing MOMP (Don et al, 2003).…”

Adenine nucleotide translocase: a component of the phylogenetically conserved cell death machinery

“…35,51 A number of additional apoptotic inducers including Ca 2 þ , ROS, nitric oxide, diamide as well as several experimental anticancer agents permeabilize ANT1-containing (but not ANT-free) liposomes, [52][53][54] suggesting that ANT is (one of) the protein(s) that might mediate MMP. Intriguingly, it has been suggested that (at least in some experimental settings) ANT1 overexpression might trigger cell death through a PT-independent mechanism relying on the ROS-dependent upregulation/activation of Bax.…”

Adenine nucleotide translocase family: four isoforms for apoptosis modulation in cancer

“…Thus, we observed that on the one hand the decrease of ANT2 levels by small-interfering RNA knock-down sensitized cells to apoptosis induction , but on the other hand increased ANT2 levels by stable overexpression in various cell lines (for example HT29 and HeLa cells) promoted chemoresistance (Gallerne et al, 2010). For instance, ANT2 downregulation renders HeLa cells resistant to Lonidamine, an anti-cancer agent whose effect is based on the induction of the mitochondrial apoptosis pathway through the ANT targeting (Ravagnan et al, 1999;Belzacq et al, 2001a;Gallerne et al, 2010). Accordingly, suppression of ANT2 by small-interfering RNA in human breast cancer cells induces apoptosis and prevents tumor growth in vitro and in vivo (Jang et al, 2008b).…”