Inhibition of apoptosis in acute promyelocytic leukemia cells leads to increases in levels of oxidized protein and LMP2 immunoproteasome

Abstract

On reaching maturity, animal organs cease to increase in size because of inhibition of cell replication activities. It follows that maintenance of optimal organ function depends on the elimination of oxidatively damaged cells and their replacement with new cells. To examine the effects of oxidative stress and apoptosis on the accumulation of oxidized proteins, we exposed acute promyelocytic leukemia cells to arsenic trioxide (As 2O3) in the presence and absence of a general caspase inhibitor (benzyloxycarbonyl-Val-AlaAsp-fluoromethyl ketone), which is known to inhibit caspaseinduced apoptosis. We confirm that treatment of cells with As 2O3 induces apoptosis and leads to the accumulation of oxidized proteins. Furthermore, inhibition of caspase activities prevented As 2O3-induced apoptosis and led to a substantial increase in accumulation of oxidized proteins. Moreover, inhibition of caspase activity in the absence of As 2O3 led to elevated levels of the LMP2 immunoproteasome protein. We also show that caspase inhibition leads to increases in the levels of oxidized proteins obtained by treatments with hydrogen peroxide plus ferrous iron. Collectively, these results suggest the possibility that an age-related loss in capacity to carry out apoptosis might contribute to the observed accumulation of oxidized proteins during aging and in age-related diseases.arsenic trioxide ͉ programmed cell death ͉ protein carbonyl NB4 cells ͉ H2O2

Knockout of caspase-like gene, YCA1 , abrogates apoptosis and elevates oxidized proteins in Saccharomyces cerevisiae

“…In previous studies, the correlation between the inhibition of apoptosis and protein carbonyl accumulation in response to indirect and direct effects of arsenic trioxide (As 2 O 3 ) and H 2 O 2 , respectively, was demonstrated in multicellular eukaryotic organisms (3). In this study, we demonstrated that the same phenomenon also exists in unicellular eukaryotic systems.…”

“…The possibility that inappropriate regulation or inhibition of apoptotic capacity might contribute to the aging process and to the development of some pathologies is underscored by the demonstration that inhibition of apoptosis in cultured mammalian acute promyelocytic leukemia-derived NB4 cells leads to a substantial increase in the accumulation of oxidized proteins (3). Both processes are characteristic of aging and many diseases (4).…”

Oxidative Stress More Strongly Induced by ortho- Than para-quinoid Polycyclic Aromatic Hydrocarbons in A549 Cells

“…2) Taken together, the above results suggest that ROS overproduced by ortho-quinoid PAHs modify protein structure through destruction of the sulfhydryl moiety. 19,20) Several ortho-qunoid PAHs such as 9,10-PQ and 9,10-AQ are present in the atmosphere at the The concentration ratios of 1,2-NQ (ortho-type) to 1,4-NQ (para-type) in the atmosphere, gasolineand diesel-engine exhausts were respectively 0.25, 1.17 and 0.09, although the concentration ratio of ortho-type to para-type was not reported for the other quinoid PAHs. 21) These facts suggest the other ortho-quinoid PAHs might also exist in the atmosphere.…”

Bioactive Poly(Arsenic) Compounds

“…These species increase mitochondrial membrane permeability, due to the alteration of membrane potential (ΔΨ) with release of cytochrome C, which activates caspases (cysteine-aspartic proteases involved in apoptosis, necrosis, and inflammation) with the final effect of inducing programmed cell death (apoptosis). Induction of apoptosis and accumulation of oxidized proteins have been observed by the treatment of cells with As 2 O 3 in the presence of inhibitors of caspase (Khan et al 2004). In addition the c-Jun N-terminal kinase (JNK) has been reported to be involved in apoptosis dependent from As 2 O 3 ; the latter one also activates the pro-apoptotic Bcl-2-associated X protein (Bax), a member of B-cell lymphoma 2 (Bcl-2) family (Fig.…”

“…It is noteworthy that arsenic trioxide was dissolved in concentrated aqueous solution of sodium hydroxide, followed by adjustment to biological pH value, in most of the reported experimental procedures (Park et al 2003a, b;Khan et al 2004;Shen et al 2004). However, it is known that arsenites are produced by treatment of As 2 O 3 with alkaline hydroxides, so that very probably the active arsenic species could not be the starting arsenic trioxide.…”