Publication Date:
2011-11-18
Description:
Abstract 1663 Backround: Honokiol, a small-molecule polyphenol isolated from Magnolia officinalis, was recently found to have antitumor properties. The agent showed cytotoxicity against CLL cells, but so far there are no data on its activity in other lymphoid tumors. More recently, new honokiol analogues (HAs) were synthetized, however, their cytotoxicity has not been investigated in leukemia/lymphoma yet. The aim: This is the first study assessing pro-apoptotic activity of new HAs on tumor cells from B-cell lymphoid malignancies. Material and Methods: Seven HAs: BR MMK + phloroG-3,3' dibromo4,4' bis (dimethlyamino) benzylidenephloroglucinol (HA 1), dibromoimipramine blue (HA 2), 3 bromo-4 dimethylamino diuhydroxyphenoxane (HA 3), bromo Gentian Violet-tribromogentian violet (HA 4), Gentian Violet (HA 5), BR dimethylaminobenzaldehyde + phloroG 3 bromo-4 dimethlyaminobenzylidenephloroglucinol (HA 6) and hexafluoro-diallylhexaflurobisphenol (HA 7) were studied. We assed ex vivo CLL cells (21 pts) and, in in vitro settings, pre-B-cell acute lymphoblastic leukemia (NALM-6), Burkitt lymphoma (Raji), diffuse large B-cell lymphoma; DLBCL (Toledo) and multiple myeloma (MM)-derived (RPMI 8226) cell lines. Lymphocytes obtained from 10 healthy volunteers were also treated. HAs were tested in concentrations 1–10 mM (24 and 48 hr incubation), then the minimal doses that triggered significant apoptosis and 48 hr time point were chosen for further experiments. Overall cytotoxicity of HAs was estimated using propydium iodide (PI) flow cytometry assay. The half maximal inhibitory concentration (IC50) of the study-drugs was estimated. Drug-induced apoptosis was assessed by the Annexin-V assay. Compensated apoptotic index (CAI) was calculated as a difference in percent of Annexin-V-positive cells between the drug-treated sample and the parallel untreated culture. Activation of caspases-8, -9 and -3 as well as expression of several apoptosis–regulating proteins, including Bcl-2 family (Bax, Bak, Bcl-2, Mcl-1), and inhibitor of apoptosis protein (IAP) family (cIAP1, cIAP2, XIAP, Smac/DIABLO) and IAP antagonists (survivin, HTRA2/Omi) were also investigated. Results: HA 1 triggered significant apoptosis in CLL cells starting from the dose 5mM, with minimal significant CAI (msCAI) 12.5%; vs. control - p=0.043 (IC50 10mM). In Raji cells msCAI was 17% at the dose 0.5mM; p=0.025 (IC50 2.5mM). In Toledo msCAI was 28% (at 0.1mM); p=0.007 (IC50 0.5mM) and RPMI 8226 (msCAI 58% at 0.5mM; p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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