Inhibition of NADPH Oxidases Activity by Diphenyleneiodonium Chloride as a Mechanism of Senescence Induction in Human Cancer Cells

Abstract

NADPH oxidases (NOX) are commonly expressed ROS-producing enzymes that participate in the regulation of many signaling pathways, which influence cell metabolism, survival, and proliferation. Due to their high expression in several different types of cancer it was postulated that NOX promote tumor progression, growth, and survival. Thus, the inhibition of NOX activity was considered to have therapeutic potential. One of the possible outcomes of anticancer therapy, which has recently gained much interest, is cancer cell senescence. The induction of senescence leads to prolonged inhibition of proliferation and contributes to tumor growth restriction. The aim of our studies was to investigate the influence of low, non-toxic doses of diphenyleneiodonium chloride (DPI), a potent inhibitor of flavoenzymes including NADPH oxidases, on p53-proficient and p53-deficient HCT116 human colon cancer cells and MCF-7 breast cancer cells. We demonstrated that the temporal treatment of HCT116 and MCF-7 cancer cells (both p53 wild-type) with DPI caused induction of senescence, that was correlated with decreased level of ROS and upregulation of p53/p21 proteins. On the contrary, in the case of p53−/− HCT116 cells, apoptosis was shown to be the prevailing effect of DPI treatment. Thus, our studies provided a proof that inhibiting ROS production, and by this means influencing ROS sensitive pathways, remains an alternative strategy to facilitate so called therapy-induced senescence in cancers.

Extracellular DNA Traps: Origin, Function and Implications for Anti-Cancer Therapies

“…Interestingly, the effects of short-term DPIC treatment on cancer cells were independent of p53. However, long-term treatment showed that p53 expression facilitates a prolonged cell cycle arrest and protects cancer cells from apoptosis, while p53 deficiency could induce apoptosis with poly ADP-ribose polymerase (PARP) cleavage and DNA fragmentation in cancer cells ( 396 ). Altogether, these results suggest that DPIC treatment can reduces tumor growth by the inhibition of cancer cell proliferation and activation of the immune system through factors secreted by senescent cancer cells.…”

Diphenyleneiodonium efficiently inhibits the characteristics of a cancer stem cell model derived from induced pluripotent stem cells

“…[9][10][11] To answer the purpose, diphenyleneiodonium chloride (DPI) was employed in this study as a candidate to inhibit NADPH oxidase resulting in the depletion of NADH attenuating ATP synthesis. 12 We tried to assess the effect of DPI on the CSC properties using miPS-Huh7cmP cells which were established as CSCs from mouse induced pluripotent stem cells (miPSCs) in the presence of the conditioned medium of human liver cancer cell line Huh7 cells. 13 VAS2870 was used as a reference molecule of NADPH oxidase inhibitor which specifically blocks the NOX isoforms but does not inhibit mitochondrial ATP synthesis.…”

“…In this energy production process NADPH oxidation is essential to salvage NADH so that inhibition of this process would be one of the targets to treat CSCs 9–11 . To answer the purpose, diphenyleneiodonium chloride (DPI) was employed in this study as a candidate to inhibit NADPH oxidase resulting in the depletion of NADH attenuating ATP synthesis 12 . We tried to assess the effect of DPI on the CSC properties using miPS‐Huh7cmP cells which were established as CSCs from mouse induced pluripotent stem cells (miPSCs) in the presence of the conditioned medium of human liver cancer cell line Huh7 cells 13 .…”

Inhibition of phase-1 biotransformation and cytostatic effects of diphenyleneiodonium on hepatoblastoma cell line HepG2 and a CYP3A4-overexpressing HepG2 cell clone

“…Its chemical nature makes DPI a potent inhibitor of flavin bearing oxidoreductases, which are generally an integral element of electron transport chains. DPI have a wide spectrum of known cellular targets including CPR [13,15,23], NADPH oxidase (NOX) [24][25][26][27][28][29][30][31], mitochondrial respiratory chain complex I (NADH ubiquinone oxidoreductase) [28,[32][33][34], and different types of nitric oxide synthase [13,35]. It is assumed that DPI inhibition is achieved by covalent modification of flavin and/or heme prosthetic groups within enzymes based on radical formation.…”

“…In the past, inhibitory effects of DPI were investigated with regard to a potential application in the therapeutic field, i.e. as an antibiotic [29,40,41], anti-cancer [31,42,43], anti-inflammatory [26,30] and/or vasodilatory agent [23]. For the analysis of phase-1 biotransformation inhibition, studies were mostly performed in less complex model systems with recombinantly expressed and purified proteins or derived from microsomal fractions in order to clarify size and range of DPI effects and the mechanism of action.…”