Ceramide influences neurite outgrowth and neuroblastoma cell apoptosis regulated by novel protein kinase C isoforms

Abstract

We have previously seen that protein kinase C (PKC) e induces neurite outgrowth and that PKCd and PKCh elicit apoptosis in neuroblastoma cells. In this study we investigate the effects of cell-permeable C 2 -ceramide on these events in SK-N-BE(2) neuroblastoma cells. C 2 -ceramide abolishes neurite formation induced by overexpression of PKCe and, in cells overexpressing PKCd or PKCh, ceramide treatment leads to apoptosis. Exposure to C 2 -ceramide also suppressed neurite outgrowth induced by retinoic acid, but ceramide did not abrogate neurite induction by treatment with the ROCK inhibitor Y-27632, demonstrating that C 2 -ceramide is not a general inhibitor of neurite outgrowth. The neurite-suppressing effect occurs independently of cell-death. Furthermore, C 2 -ceramide relocated PKCe and the isolated regulatory domain of PKCe from the cytosol to the perinuclear region. In contrast, neither the localization of PKCd nor of PKCh was affected by C 2 -ceramide. Taken together, the data indicate that the neuriteinhibiting effect of C 2 -ceramide treatment may be caused by a re-localization of PKCe and thus identify a functional consequence of ceramide effects on PKCe localization.

Identification of an Amino Acid Residue in the Protein Kinase C C1b Domain Crucial for Its Localization to the Golgi Network

“…9A). Treatment with TPA relocates the fusion protein to the plasma membrane, and, as reported previously (8,29), treatment with C 2 -ceramide induces a clear enrichment of ⑀FL in the perinuclear region. Combined treatment of C 2 -ceramide and TPA leads to a primarily cytoplasmic localization of ⑀FL-wt, which is analogous with studies on other cell types (8).…”

“…We have previously shown that treatment with C 2 -ceramide induces a relocation of PKC⑀ to perinuclear structures that is accompanied by a suppression of the neurite-inducing capacity of PKC⑀ (29). The results in Fig.…”

Ethanol-Induced Changes in the Content of Triglycerides, Ceramides, and Glucosylceramides in Cultured Neurons

“…It is also possible that there are differences among these neurons in cellular targets for ceramide, which affect differentiation, proliferation, and cell death. It has been reported that the capacity of ceramide to induce apoptosis in SK-N-BE cells correlates with the expression levels of PKC-␦, which is a possible target of ceramide (Schultz and Larsson, 2004). Another intriguing possibility is that not only ceramide but also GlcCer affects the apoptotic pathway.…”

Interplay Between Protein Kinase C Isoforms Alpha and Epsilon, Neurofibromin, and the Ras/MAPK Pathway in Neuroblastoma Differentiation

“…Silei et al, 2000;Fagerstrom et al, 1996), but there is still some controversy for the contribution of other nPKCs, namely PKC and . PKC , expressed occasionally in NB cells or tumors (Zeidman et al, 1999b), may contribute to apoptotic pathways in SK-N-BE(2) and SH-SY5Y cells (Schultz & Larsson, 2004;Schultz et al, 2003). Unlike , is commonly expressed (Zeidman et al, 1999b), yet again, transfection studies with full-length, catalytically inactive, or active PKC variants have revealed a pro-apoptotic role (Schultz et al, 2003;Schultz & Larsson, 2004).…”

“…PKC , expressed occasionally in NB cells or tumors (Zeidman et al, 1999b), may contribute to apoptotic pathways in SK-N-BE(2) and SH-SY5Y cells (Schultz & Larsson, 2004;Schultz et al, 2003). Unlike , is commonly expressed (Zeidman et al, 1999b), yet again, transfection studies with full-length, catalytically inactive, or active PKC variants have revealed a pro-apoptotic role (Schultz et al, 2003;Schultz & Larsson, 2004). A major role of PKC in the sensitization of NB cells (SH-SY5Y and SK-N-BE(2C)) to etoposide (Marengo et al, 2011) was just recently described, validating similar observations in other cell types (Griner and Katanietz, 2007).…”