Daunorubicin-induced apoptosis: triggering of ceramide generation through sphingomyelin hydrolysis.

Abstract

The nature of the signaling pathway(s) which initiate drug‐triggered apoptosis remains largely unknown and is of fundamental importance in understanding cell death induced by chemotherapeutic agents. Here we show that in the leukemic cell lines U937 and HL‐60, daunorubicin, at concentrations which trigger apoptosis, stimulated two distinct cycles of sphingomyelin hydrolysis (approximately 20% decrease at 1 microM) within 4–10 min and 60–75 min with concomitant ceramide generation. We demonstrate that the increase in ceramide levels, which precedes apoptosis, is mediated by a neutral sphingomyelinase and not by ceramide synthase. Indeed, potent ceramide synthase inhibitors such as fumonisin B1 did not affect daunorubicin‐triggered sphingomyelin hydrolysis, ceramide generation or apoptosis. In conclusion, we provide evidence that daunorubicin‐triggered apoptosis is mediated by a signaling pathway which is initiated by an early sphingomyelin‐derived ceramide production.

Influence of Bax or Bcl-2 overexpression on the ceramide-dependent apoptotic pathway in glioma cells

“…A number of extracellular stimuli, not only various cytokines including tumor necrosis factor (TNF)-a, interferon-g (Kim et al, 1991;Dressler et al, 1992), interleukin-1b (Ballou et al, 1992), nerve growth factor (Dobrowsky et al, 1994), and activators of Fas receptor (Cifone et al, 1994), but also physical stresses including heat shock, irradiation and chemotherapeutic drugs (Verheij et al, 1996;Santana et al, 1996;Ja rezou et al, 1996) are shown to cause sphingomyelin (SM) hydrolysis via sphingomyelinase (SMase), leading to elevation of intracellular ceramide, although several recent reports have questioned the role of ceramide in apoptosis induced by Fas or TNF-a (Sillence and Allen, 1997; Hsu et al, 1998;Watts et al, 1997Watts et al, , 1999a. The addition of exogenous ceramide has been associated with several antiproliferative responses including cell di erentiation, apoptosis, and cell cycle arrest (Okazaki et al, 1990;Kolesnick and Hannun, 1999).…”

Pharmacological inhibition or small interfering RNA targeting acid ceramidase sensitizes hepatoma cells to chemotherapy and reduces tumor growth in vivo

“…Daunorubicin (DNR) has been shown to elicit ceramide generation (Bose et al, 1995;Jaffrezou et al, 1996), and as ceramide catabolism limits its participation in apoptotic pathways, we determined whether DNR regulates the activities of enzymes that metabolize ceramide. DNR dose dependently caused a rapid and selective activation of acid CDase in HepG2 cells, reaching a maximum at 30 min after drug treatment, without effect on the neutral/alkaline CDases (Figure 1a,b).…”

Neutral Sphingomyelinase-3 Is a DNA Damage and Nongenotoxic Stress-Regulated Gene That Is Deregulated in Human Malignancies

“…This is evidenced by numerous cell-based and animal studies showing the ability of ceramide to induce cell cycle arrest or apoptosis (9)(10)(11). Furthermore, ceramide has been shown to function as a key mediator of apoptosis brought on by stress-inducing therapeutic agents, such as anthracyclines (11)(12)(13)(14), ionizing radiation (15,16), tumor necrosis factor (TNF)-related apoptosis-inducing ligand (17), and paclitaxel (18). Reciprocally, the inhibition of ceramide production by compounds such as the ceramide synthase inhibitor fumonisin B1 or by small interfering RNA approaches has been shown to abrogate stress-induced apoptosis (11,(19)(20)(21).…”

“…The modulation of ceramide levels (a) by stress-inducing agents (11)(12)(13)(14)(15)(16)(17)(18) or (b) as noted in multiple primary tumor types (reviewed in refs. 3,22) is likely to result due to multiple changes in the regulation of ceramide-metabolizing enzymes or pathways; however, the exact molecular mechanisms responsible for these alterations remain unclear.…”