Nitric Oxide–Donating Acetylsalicylic Acid Induces Apoptosis in Chronic Lymphocytic Leukemia Cells and Shows Strong Antitumor Efficacy In vivo

Abstract

Purpose: Nitric oxide-donating acetylsalicylic acid (NO-ASA) has been shown to possess an antineoplastic effect in Wnt-/b-catenin-active cancers. As chronic lymphocytic leukemia (CLL) cells exhibit aberrantly active Wnt signaling, we investigated the effect of the para-isomer of NO-ASA on CLL cell survival in vitro and in a CLL-like xenograft mouse model.Experimental Design: Apoptosis in primary CLL cells was determined by flow cytometric annexin V-FITC (fluorescein isothiocyanate)/PI (propidium iodide) staining and immunoblotting of caspases, poly(ADP-ribose) polymerase (PARP), and antiapoptotic proteins. Interference of NO-ASA with Wnt/ b-catenin signaling was analyzed through immunoblots of different pathway members. Influence of caspase activation was investigated by pretreatment with a pan-caspase inhibitor. CLL-like JVM3 cells were subcutaneously inoculated into irradiated nude mice that were treated with 100 mg of para-NO-ASA/kg of body weight p.o. (by mouth) for 21 days.Results: para-NO-ASA induced apoptosis in CLL cells with an LC 50 (lethal concentration) of 8.72 þ 0.04 mmol/L, whereas healthy blood cells were not affected. Furthermore, the compound induced caspase 9, caspase 3, and PARP cleavage. In addition, cleavage of b-catenin and downregulation of b-catenin/ lymphoid enhancer factor (Lef)-1 targets was observed. para-NO-ASA demonstrated strong antitumor efficacy in the xenograft mouse model with a tumor inhibtion rate of 83.4%. During therapy, no gross toxicity could be observed.Conclusions: para-NO-ASA selectively induces apoptosis in primary CLL cells and efficiently reduces tumor growthin a CLL-likexenograftmodel. As NO-ASA is orally available and is generally welltolerated, para-NO-ASA might be a promising new compound for CLL therapy. Clin Cancer Res; 17(2); 286-93. Ó2010 AACR.

The antineoplastic effect of nitric oxide-donating acetylsalicylic acid (NO-ASA) in chronic lymphocytic leukemia (CLL) cells is highly dependent on its positional isomerism

“…Furthermore, the Wnt/b-catenin/TCF/Lef-1 signaling pathway is aberrantly active [Lu et al 2004] and its therapeutic inhibition has been demonstrated to induce apoptosis in primary CLL cells in vitro and reduce tumor growth in a xenograft mouse model [Gandhirajan et al 2010]. We have recently demonstrated, confirming data obtained in solid tumors, that para-NO-ASA potently induced apoptosis in vitro in primary CLL cells and prevented tumor growth in a xenograft CLL-like mouse model [Razavi et al 2011]. Also here b-catenin cleavage was involved in apoptotic cell death.…”

The heparan sulfate mimetic PG545 interferes with Wnt/β-catenin signaling and significantly suppresses pancreatic tumorigenesis alone and in combination with gemcitabine

“…3 and 4). The induction of cleavage of the apoptotic proteins caspase 3, caspase 9 and PARP has been linked to blockade of Wnt/β-catenin signaling and provides further evidence that promotion of apoptosis by PG545 was being driven by Wnt inhibition [28-31]. The contrasting effects of PG545 on β-catenin in our AsPC-1 xenograft model compared to the mPDAC genetic model described by Ostapoff and colleagues may suggest differences in β-catenin regulation between human and mouse pancreatic tumors.…”

In vitro evaluation of novel N-acetylalaninate prodrugs that selectively induce apoptosis in prostate cancer cells

“…Four chiral N-acetylalaninate ester prodrugs (see Figure  3) were evaluated in this study based on: (1) our previous experimental observations showing that OPH has specificity towards α-naphthyl-N-acetylalaninate substrates [24]; (2) in silico protein-ligand binding studies suggesting that S-NPAA has a reasonable affinity to the active site found in predicted three dimensional models of rat and human OPH [23]; (3) structural similarity to NO-ASA which has a toxicology profile superior to that of aspirin [18]. Our first objective was to determine whether the hydrolysis of the newly designed prodrugs was catalyzed, and thus activated, by OPH.…”

“…S-NPAA was found to deplete GSH in a manner completely analogous to that of NO-ASA, a well-characterized anti-cancer drug with minimal in vivo toxicity [18]. NO-ASA exerts an anticancer effect by depleting intracellular GSH and causing oxidative stress induced apoptosis by activation of the intrinsic death pathway [15].…”