Transcriptional regulation of neutral sphingomyelinase 2 gene expression of a human breast cancer cell line, MCF-7, induced by the anti-cancer drug, daunorubicin

ATRA transcriptionally induces nSMase2 through CBP/p300-mediated histone acetylation

“…Previously, we reported that nSMase2 is an early induced gene in the ATRA response and is regulated in a nSMase2 promoter activity (19). Indeed, as seen with daunorubicin, low-dose doxorubicin increased the activity of the nSMase2 promoter compared with vehicle control (Fig.…”

“…Indeed, emerging evidence has begun to point to a more protracted regulation of at the transcriptional level. Increases in nSMase2 expression have been reported in response to bone morphogenetic protein-2 (BMP2) (17,18), daunorubicin (19), cigarette smoke (20), confluence (6), the hedgehog signaling mediator cyclopamine (21), and all-trans retinoic acid (ATRA) (5,22,23). Notably, in the latter two cases, increased expression of nSMase2 was required for ATRA-induced growth arrest (23) and cyclopamine-induced apoptosis, respectively (21).…”

“…As shown, protein was extracted in RIPA buffer, and nSMase2 levels analyzed by immunoblot using actin as loading control. to various stimuli (17)(18)(19)21). Indeed, Sp1 and Sp3 were reported to be upstream of nSMase2 in the ATRA response, although this was inferred by use of pharmacological inhibition (22).…”

“…Additionally, expression of nSMase2 was increased in mature osteoblasts compared with mesenchymal precursors, consistent with a role for nSMase2 in bone homeostasis (10). However, despite multiple known inducers of nSMase2, to date only three transcription factors have been implicated in regulating nSMase2 expression; Sp1 and Sp3 were suggested to be important for daunorubicin and ATRA responses (19,22) while Runx2 was implicated in the BMP2 response in both osteoblasts and chondrocytes (17,18). In addition, cyclopamine induction of nSMase2 required generation of reactive nitrogen species (RNS) and was sensitive to treatment with N-acetylcysteine (NAC) (21).…”

“…Surprisingly, and in contrast to doxorubicin, ATRA did not increase promoter activity. This was also the region spanning from 1,100 bp to +25 bp upstream of exon 1 as described previously (17)(18)(19)22), and reporter assays were performed as described above. For these experiments, we utilized doxorubicin as a positive control as its analog daunorubicin was previously reported to increase (1 or 5 M) for 20 min prior to stimulation with DMSO or ATRA (1 M) for 24 h (* P < 0.05 vs. vehicle, n = 4).…”