Analysis of resveratrol‐induced apoptosis in human B‐cell chronic leukaemia

Abstract

Summary. Trans-resveratrol was analysed for its apoptotic and growth inhibitory activity in human B-cell lines derived from chronic B-cell malignancies (WSU-CLL and ESKOL), and in leukaemic lymphocytes from patients with B-cell chronic lymphocytic leukaemia (B-CLL). Resveratrol displayed antiproliferative activity on both B-cell lines, as estimated by the decrease in cell recovery and inhibition of thymidine uptake. Furthermore, resveratrol induced apoptosis in the two cell lines as well as in B-CLL patients' cells, as evidenced by the increase in annexin V binding, caspase activation, DNA fragmentation and decrease of the mitochondrial transmembrane potential DY m . We previously reported that nitric oxide (NO), endogenously released by an iNO synthase (iNOS) spontaneously expressed in these leukaemic cells, contributed to their resistance towards apoptosis. We show here that resveratrol inhibited both iNOS protein expression and in situ NO release in WSU-CLL, ESKOL and B-CLL patients'cells. In addition, Bcl-2 expression was also inhibited by resveratrol. Thus, downregulation of the two anti-apoptotic proteins iNOS and Bcl-2 can contribute to the apoptotic effects of resveratrol in leukaemic B cells from chronic leukaemia. Our data suggest that this drug is of potential interest for the therapy of B-CLL.

Flavopiridol downregulates the expression of both the inducible NO synthase and p27kip1 in malignant cells from B-cell chronic lymphocytic leukemia

“…Since previous Western blot analysis of the effects of flavopiridol on Bcl-2 expression provided conflicting results, we decided to measure the intracellular content of Bcl-2 with a quantitative ELISA, as described. 19,20 Bcl-2 levels in B-CLL cells were found to be markedly reduced by flavopiridol (1 mM), as presented in Table 3. The same concentration of flavopiridol also triggered a dissipation in the leukemic cells of the mitochondrial transmembrane potential DCm, as detected with the specific fluorescent probe JC-1 for the three patients tested (Figure 4c), confirming that mitochondrial events occur during flavopiridol-stimulated apoptosis of B-CLL cells.…”

“…7 We show that flavopiridol inhibits both iNOS expression and NO production in B-CLL cells in vitro, an effect already observed during apoptosis induced by resveratrol 19 and other polyphenols. 20 The latter could be due to a stimulation of iNOS degradation by the proteasome following transcriptional downregulation.…”

Pro-apoptotic properties of hyperforin in leukemic cells from patients with B-cell chronic lymphocytic leukemia

“…28 We showed recently that several plant-derived compounds, such as flavopiridol, 21 polyphenols (including resveratrol) and their acetate derivatives as well as a synthetic aminoflavone, induced both apoptosis of B-CLL patients' cells and downregulation of iNOS expression and NO production. 22,20,29 HF thus represents another example of a natural compound capable of promoting apoptosis and inhibiting the NO pathway in B-CLL cells. This inhibition of the NO pathway could be either a cause or a consequence of apoptosis.…”

Nitric Oxide and Cancer Development

“…They also discovered that treatment of H460 cells with the stress inducers Fas ligand or buthionine sulfoxide also induced Bcl-2 S-nitrosylation. Several observations clearly demonstrate that nitric oxide from iNOS involving Bcl-2 is important in preventing normal B-cell lymphocyte apoptosis 143 , as in human B-cell lymphomas [144][145][146] . In the case of the treatment of B-cell lymphomas with resveratrol, it was shown to prevent iNOS expression, to cause decreased expression levels of Bcl-2, and to enhance cellular apoptosis 145,146 .…”

“…Several observations clearly demonstrate that nitric oxide from iNOS involving Bcl-2 is important in preventing normal B-cell lymphocyte apoptosis 143 , as in human B-cell lymphomas [144][145][146] . In the case of the treatment of B-cell lymphomas with resveratrol, it was shown to prevent iNOS expression, to cause decreased expression levels of Bcl-2, and to enhance cellular apoptosis 145,146 . Intravenous administration of natural polyphenols to mice bearing metastatic B16 melanomas enhanced apoptosis as well as decreased Bcl-2 expression in the metastatic cells involving nitric oxide dependent processes 147 .…”