The Para-Isomer of Nitric Oxide Donating Acetylsalicylic Acid (p-NO-ASA) Induces Apoptosis in Chronic Lymphocytic Leukemia (CLL) in Vitro and In Vivo without Gross Systemic Toxicities

• Published in: Blood 2009-11, Vol.114 (22), p.3783-3783
• Main Authors: Razavi, Regina, Gehrke, Iris, Gandhirajan, Rajesh Kumar, Poll-Wolbeck, Simon Jonas, Paesler, Julian, Erdfelder, Felix, Hertweck, Magdalena, Filipovich, Alexandra, Uhrmacher, Sabrina, Hallek, Michael, Kreuzer, Karl Anton
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V114.22.3783.3783

Abstract 3783 Poster Board III-719 Chronic lymphocytic leukemia (CLL) is characterized by an accumulation of mature, non functional B cells. WNT/β-catenin(CTNNB1)/TCF/Lef-1 signalling appears to be constitutively and aberrantly activated in these cells. Furthermore, several compounds related to the non-steroidal anti-inflammatory drugs (NSAIDs) are reported to inhibit β-catenin stability and/or function in WNT active cancers in vitro. However, so far clinical studies with such substances generated disappointing results which is likely to the fact that therapeutic plasma concentrations could not be reached without producing significant toxicities; hence, the required high concentrations limit their clinical use. Recently, nitric oxide-donating acetylsalicylic acid (NO-ASA) has been shown to achieve high plasma levels in doses not leading to any relevant side effects in humans. In addition, NO-ASA could disrupt complexation of β-catenin and TCF-4 in vitro. Because the general structure of NO-ASA enables more variants, the aim of our study was to evaluate the effect of the para- (p-NO-ASA) and meta-isomer (m-NO-ASA) in CLL in vitro and in vivo. Primary CLL cells as well as healthy peripheral blood monocytes (PBMCs) and healthy B cells were treated with varying concentrations of p- and m-NO-ASA. Cytotoxicity was assessed by microscopic cell viability testing and measurement of the reduction of the ATP content. Induction of apoptosis was investigated by Annexin V-FITC/propidiumiodide staining and immunoblotting of the caspases-9, -3 as well as PARP. Further, the β-catenin protein amount and the expression of WNT effector proteins like cyclin D1 (CCND1), C-MYC and LEF-1 was evaluated by immunoblot analysis. In vivo activity of NO-ASA was evaluated by treating irradiated CD1 nu/nu female mice, containing a JVM-3 cell line xenograft, with 100 mg/kg/day of p- and m-NO-ASA or vehicle control p.o. for 3 weeks continuously. We found a significant concentration dependent reduction of the ATP content in CLL cells after treatment with p-NO-ASA, whereas the meta-isomer showed no effect on CLL cells. While healthy B cells and healthy PBMCs were not significantly affected by any of the isomers the mean lethal concentration (LC50) was 4.64 μM in CLL cells. Annexin V-FITC/PI staining revealed that reduced cell survival occurs in a time and concentration dependent manner and is mediated by apoptosis. Treatment with 10 μM of p-NO-ASA for 24 hours reduced survival to 46.3 ± 10.1