201
Moreover, adding the exogenous ceramide stimulates programmed
cell death and ceramide generation is an essential controller of
apoptosis [17, 18].
Ceramide and sphingosine-1-phosphate (S1P) have long been
suggested to have opposing missions in the regulation of cell fate
[19]. Although ceramide has been related to cell growth arrest and
apoptosis, S1P induces cell growth and survival [8]. Studies have
recently suggested that ceramide and S1P have as well opposing
impacts on autophagy [20]. The rise of ceramide enhances the
assemblage of Beclin-1 and the suppression of AKT phosphorylation that causes autophagic cell death [21]. The association of the
multi-kinase inhibitor sorafenib with histone deacetylase inhibitors
also raises ceramide levels notably by the promotion of de novo
synthesis. Increased ceramide synthesis has been implicated in
endoplasmic reticulum (ER) stress, autophagy, and apoptosis [22].
Additionally, exogenous dihydroceramide, an intermediate in the
biosynthesis of ceramide, or its promotion resulted from the fenretinide, which stimulates serine palmitoyl-transferase and inhibits
the desaturase, also inducing autophagy [23].
The factors enhancing or preventing ceramide operators and
sphingolipid-metabolizing enzymes have recently been regarded as
novel pharmacological goals for controlling apoptosis [24]. Other
cellular procedures which depend on these messengers have been
the subject of discussion of different biological studies [25].
Therefore, these data support the hypothesis that the alteration of
the metabolic activity of ceramidase and increased ceramide levels
are the key role in the induction of cancer cell apoptosis or tumor
suppression [26].
In the following data analysis ceramide takes a focal position in
biosynthesis and catabolism and as a precursor of complex sphingolipids, currently thereby considered as a metabolic hub of sphingolipid metabolism. Ceramide can be produced by three different
pathways: salvage, degradation or hydrolytic, and de novo biosynthesis pathway. On the contrary, there has been increasing evidence
that lipid mediators such as ceramide and sphingosine-1-phosphate
(S1P) have crucial roles in various human cancers [27], involving
breast [28] and prostate cancer [29]. S1P is generated inside the
cancer cells and exported out of the cells where it regulates many
functions in tumor microenvironment by binding to specific G
protein-coupled receptors expressed either in cancer cells or in
host cells, known as the “inside-out” signaling of S1P. In addition,
it has demonstrated that S1P levels are high not only in tumors,
but also in the tumor microenvironment. However, studies further
explained that high S1P production by tumor is linked to lymph
node metastasis, showing that S1P enhances cancer metastasis by
influencing tumor microenvironment in human breast cancer.
Thus, it was of great interest to examine the ceramide levels of
1.1 Sphingolipid
Metabolism
and Cancer
Antitumor Efficacy of Ceranib-2 with Nano-Formulation of PEG and Rosin Esters
Moreover, adding the exogenous ceramide stimulates programmed
cell death and ceramide generation is an essential controller of
apoptosis [17, 18].
Ceramide and sphingosine-1-phosphate (S1P) have long been
suggested to have opposing missions in the regulation of cell fate
[19]. Although ceramide has been related to cell growth arrest and
apoptosis, S1P induces cell growth and survival [8]. Studies have
recently suggested that ceramide and S1P have as well opposing
impacts on autophagy [20]. The rise of ceramide enhances the
assemblage of Beclin-1 and the suppression of AKT phosphorylation that causes autophagic cell death [21]. The association of the
multi-kinase inhibitor sorafenib with histone deacetylase inhibitors
also raises ceramide levels notably by the promotion of de novo
synthesis. Increased ceramide synthesis has been implicated in
endoplasmic reticulum (ER) stress, autophagy, and apoptosis [22].
Additionally, exogenous dihydroceramide, an intermediate in the
biosynthesis of ceramide, or its promotion resulted from the fenretinide, which stimulates serine palmitoyl-transferase and inhibits
the desaturase, also inducing autophagy [23].
The factors enhancing or preventing ceramide operators and
sphingolipid-metabolizing enzymes have recently been regarded as
novel pharmacological goals for controlling apoptosis [24]. Other
cellular procedures which depend on these messengers have been
the subject of discussion of different biological studies [25].
Therefore, these data support the hypothesis that the alteration of
the metabolic activity of ceramidase and increased ceramide levels
are the key role in the induction of cancer cell apoptosis or tumor
suppression [26].
In the following data analysis ceramide takes a focal position in
biosynthesis and catabolism and as a precursor of complex sphingolipids, currently thereby considered as a metabolic hub of sphingolipid metabolism. Ceramide can be produced by three different
pathways: salvage, degradation or hydrolytic, and de novo biosynthesis pathway. On the contrary, there has been increasing evidence
that lipid mediators such as ceramide and sphingosine-1-phosphate
(S1P) have crucial roles in various human cancers [27], involving
breast [28] and prostate cancer [29]. S1P is generated inside the
cancer cells and exported out of the cells where it regulates many
functions in tumor microenvironment by binding to specific G
protein-coupled receptors expressed either in cancer cells or in
host cells, known as the “inside-out” signaling of S1P. In addition,
it has demonstrated that S1P levels are high not only in tumors,
but also in the tumor microenvironment. However, studies further
explained that high S1P production by tumor is linked to lymph
node metastasis, showing that S1P enhances cancer metastasis by
influencing tumor microenvironment in human breast cancer.
Thus, it was of great interest to examine the ceramide levels of
1.1 Sphingolipid
Metabolism
and Cancer
Antitumor Efficacy of Ceranib-2 with Nano-Formulation of PEG and Rosin Esters