Ceramide induces early and late apoptosis in human papilloma virus+ cervical cancer cells by inhibiting reactive oxygen species decay, diminishing the intracellular concentration of glutathione and increasing nuclear factor-κB translocation

Abstract

Ceramide is regarded as an important cellular signal for the induction of cell death. We have previously shown that ceramide induces the death of cervical tumor cells without biochemical and morphological markers of apoptosis. The mechanisms by which ceramide induces cell death are not understood, therefore we evaluated the effect of C6-ceramide, a synthetic cell-permeable analog of endogenous ceramides, in signaling pathways involved in the oxidative stress of three cervical human papilloma virus cancer cell lines. Reactive oxygen species production was determined by fluorescent 2,7-dichlorofluorescein, nitrite concentration by the Griess reaction (as an indirect measure of nitric oxide production), mitochondrial membrane potential by staining with Rh123, reduced-glutathione concentration by high-pressure liquid chromatography, nuclear factor-kappaB translocation by electrophoretic mobility shift assay, inhibitory protein of nuclear factor-kappaB expression by Western blot and cell death by a poly-caspases fluorochrome-labeled inhibitors of caspases apoptosis assay. C6-ceramide induced early and late apoptosis, which was associated with an increase in reactive oxygen species and nitric oxide production, a loss in mitochondrial membrane potential, an increase in nuclear factor-kappaB translocation, and a decrease in reduced glutathione concentration. C6-ceramide did not modify the expression of inhibitory protein of nuclear factor-kappaB and its antiproliferative effect was not abrogated by Bay 11-7082, an inhibitory protein of nuclear factor-kappaB kinase inhibitor. Our results suggest that oxidative stress might participate in the ceramide-induced damage to human papilloma virus cervical cancer cells.

Tamoxifen magnifies therapeutic impact of ceramide in human colorectal cancer cells independent of p53

“…3C, bar graph), whereas the combination produced both supra-additive DNA fragmentation and caspase-3 activation and subsequent PARP cleavage. It is well known that natural ceramides activate pro-apoptotic events; the same has been demonstrated with short-chain ceramides [41–43]. Interestingly, in a model of human keratinocytes, C6-ceramide exposure induced apoptosis via the salvage pathway [44], wherein C6-ceramide is hydrolyzed by ceramidase, and the liberated sphingosine reacylated by ceramide synthase to generate long-chain ceramides.…”

Conjugated linoleic acid-induced apoptosis in mouse mammary tumor cells is mediated by both G protein coupled receptor-dependent activation of the AMP-activated protein kinase pathway and by oxidative stress

“…Phosphatidylcholine-specific PLC (PC-PLC), which is activated by t10,c12-CLA in adipocytes [48], has been shown to cause lysosomal destabilization [80]. This enzyme can also activate sphingomyelinase to promote the processing of sphingolipid into ceramide [81,82], a lipid messenger which has been shown to promote oxidative stress, induce ER stress and cause apoptosis [83-85]. Third , release of Ca 2+ from the ER promotes ER stress [86,87], and there is increasing evidence suggesting that ER stress can induce ROS formation [38,41,88], thus creating a vicious cycle since oxidative stress can induce ER stress [24,25].…”

Delivery of long chain C16 and C24 ceramide in HeLa cells using oxidized graphene nanoribbons

“…It has been previously demonstrated that graphene oxide nanoparticles can act as anti‐oxidants and allow the buffering of reaction oxygen species (ROS) (Qiao, Zhang, Wang, Ma, & Su, ). ROS is an important cell signaling mechanism that has largely pro‐apoptotic effects, and has been shown to be an important mediator of both UV and C 6 ceramide induced apoptosis (Artyukhov, Trubitsyna, Nakvasina, & Solov'eva, ; Degli Esposti & McLennan, ; Gutierrez, Mendoza, Montano, & Lopez‐Marure, ; Valencia & Kochevar, ). In this case, we have demonstrated that O‐GNRs alone are capable of rescuing HeLa cells from the pro‐apoptotic stressors of UV irradiation and C 6 ceramide (Figures and ).…”