γ-Tocotrienol induces apoptosis in pancreatic cancer cells by upregulation of ceramide synthesis and modulation of sphingolipid transport

Abstract

BackgroundCeramide synthesis and metabolism is a promising target in cancer drug development. γ-tocotrienol (GT3), a member of the vitamin E family, orchestrates multiple effects that ensure the induction of apoptosis in both, wild-type and RAS-mutated pancreatic cancer cells. Here, we investigated whether these effects involve changes in ceramide synthesis and transport.MethodsThe effects of GT3 on the synthesis of ceramide via the de novo pathway, and the hydrolysis of sphingomyelin were analyzed by the expression levels of the enzymes serine palmitoyl transferase, ceramide synthase-6, and dihydroceramide desaturase, and acid sphingomyelinase in wild-type RAS BxPC3, and RAS-mutated MIA PaCa-2 and Panc 1 pancreatic cancer cells. Quantitative changes in ceramides, dihydroceramides, and sphingomyelin at the cell membrane were detected by LCMS. Modulation of ceramide transport by GT3 was studied by immunochemistry of CERT and ARV-1, and the subsequent effects at the cell membrane was analyzed via immunofluorescence of ceramide, caveolin, and DR5.ResultsGT3 favors the upregulation of ceramide by stimulating synthesis at the ER and the plasma membrane. Additionally, the conversion of newly synthesized ceramide to sphingomyelin and glucosylceramide at the Golgi is prevented by the inhibition of CERT. Modulation ARV1 and previously observed inhibition of the HMG-CoA pathway, contribute to changes in membrane structure and signaling functions, allows the clustering of DR5, effectively initiating apoptosis.ConclusionsOur results suggest that GT3 targets ceramide synthesis and transport, and that the upregulation of ceramide and modulation of transporters CERT and ARV1 are important contributors to the apoptotic properties demonstrated by GT3 in pancreatic cancer cells.

Acid sphingomyelinase downregulation alleviates vascular endothelial leptin resistance in rats

“…ASM catalyzes the hydrolysis of sphingomyelin to produce ceramide. Here, according to the methods described by Li et al [ 11 ], Palau et al [ 13 ] and Maroni et al [ 20 ], RAECs were incubated with an anti-ceramide antibody followed by goat anti-mouse IgG-FITC. As shown in Fig.…”

“…Immunofluorescence of ceramide was measured according to the methods described by Li et al [ 11 ] and Palau et al [ 13 ]. RAECs were plated in a six-well plate.…”

Extraction of Lipophilic Fraction from Polished Rice Improves Its Ameliorative Effect on Intestinal Impairment

“…RE also contains small amounts of FA and T3, which are known to have anti-cancer and anti-inflammatory properties Table 1 19,20 . It was recently, reported that T3 controls the synthesis and metabolism of intrinsic sphingolipids, including GlcCer, in the colon and pancreatic cancer cells in vitro 23,24 . Additionally, when both T3 and free FA are added to the colon and pancreatic cancer cells in vitro, intracellular T3 concentrations are higher than when T3 is added alone 25,26 .…”

Molecular Mechanisms of Action of Tocotrienols in Cancer: Recent Trends and Advancements

“…Hence, targeting cell cycle checkpoints can be an important strategy for cancer therapy [61]. Recent scientific evidence has documented the potential role of tocotrienols as therapeutic agents in cancer treatment through the modulation of cell cycle proteins in pancreatic cancer [62,63], leukemia [64,65], glioblastoma [66], gastric cancer [67], neuroblastoma [68] etc. In another study, Abubakar et al, (2017) documented the anti-proliferative potency of γ-T3 and jerantinine A in brain cancer (U87MG) cells, and found that the combination can lead to G0/G1 cell cycle arrest and trigger disruption of microtubule networks, thus promoting Fas and p53 induced apoptosis mediated through the death receptor and mitochondrial pathways (Figure 3) [69].…”