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C16-Ceramide Analog Combined with Pc 4 Photodynamic Therapy Evokes Enhanced Total Ceramide Accumulation, Promotion of DEVDase Activation in the Absence of Apoptosis, and Augmented Overall Cell Killing.

Separovic D, Saad ZH, Edwin EA, Bielawski J, Pierce JS, Buren EV, Bielawska A - J Lipids (2010)

Bottom Line: Using SCCVII mouse squamous carcinoma cells, and the silicone phthalocyanine Pc 4 for PDT, we showed that combining PDT with LCL30 (PDT/LCL30) was more effective than individual treatments in raising global ceramide levels, as well as in reducing dihydrosphingosine levels.Notably, treatment with the combination resulted in augmented overall cell killing.Our data demonstrate that treatment with PDT/LCL30 leads to enhanced global ceramide levels and DEVDase activation in the absence of apoptosis, and promotion of total cell killing.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.

ABSTRACT
Because of the failure of single modality approaches, combination therapy for cancer treatment is a promising alternative. Sphingolipid analogs, with or without anticancer drugs, can improve tumor response. C16-pyridinium ceramide analog LCL30, was used in combination with photodynamic therapy (PDT), an anticancer treatment modality, to test the hypothesis that the combined treatment will trigger changes in the sphingolipid profile and promote cell death. Using SCCVII mouse squamous carcinoma cells, and the silicone phthalocyanine Pc 4 for PDT, we showed that combining PDT with LCL30 (PDT/LCL30) was more effective than individual treatments in raising global ceramide levels, as well as in reducing dihydrosphingosine levels. Unlike LCL30, PDT, alone or combined, increased total dihydroceramide levels. Sphingosine levels were unaffected by LCL30, but were abolished after PDT or the combination. LCL30-triggered rise in sphingosine-1-phosphate was reversed post-PDT or the combination. DEVDase activation was evoked after PDT or LCL30, and was promoted post- PDT/LCL30. Neither mitochondrial depolarization nor apoptosis were observed after any of the treatments. Notably, treatment with the combination resulted in augmented overall cell killing. Our data demonstrate that treatment with PDT/LCL30 leads to enhanced global ceramide levels and DEVDase activation in the absence of apoptosis, and promotion of total cell killing.

No MeSH data available.


Related in: MedlinePlus

PDT, with or without LCL30, has no effect on mitochondrial membrane potential or apoptosis. Following incubations, cells were collected and processed for flow cytometry. JC-1 and Annexin V/PI staining were used to detect mitochondrial membrane potential (a) and apoptosis (b), respectively. See Section 2 for other details. (a) Percentage of cells with depolarized mitochondria is shown in lower right dot plot. (b) Percentage of Annexin V (+)/PI (−) and Annexin V (+)/PI (+) is shown in lower right and upper right dot plot, respectively. The representative data for PDT, with or without LCL30, from two independent experiments are shown.
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fig4: PDT, with or without LCL30, has no effect on mitochondrial membrane potential or apoptosis. Following incubations, cells were collected and processed for flow cytometry. JC-1 and Annexin V/PI staining were used to detect mitochondrial membrane potential (a) and apoptosis (b), respectively. See Section 2 for other details. (a) Percentage of cells with depolarized mitochondria is shown in lower right dot plot. (b) Percentage of Annexin V (+)/PI (−) and Annexin V (+)/PI (+) is shown in lower right and upper right dot plot, respectively. The representative data for PDT, with or without LCL30, from two independent experiments are shown.

Mentions: We have shown that PDT combined with C16-ceramide enhances mitochondrial depolarization in Jurkat cells undergoing apoptosis [36]. Here, we tested whether PDT/LCL30 triggers the collapse of mitochondrial potential in SCCVII cells. As depicted in Figure 4(a), neither individual treatments nor the combination had any effect on mitochondrial membrane potential. In contrast, overnight treatment with camptothecin (5 μM) led to the appearance of 63% cells with depolarized mitochondria.


C16-Ceramide Analog Combined with Pc 4 Photodynamic Therapy Evokes Enhanced Total Ceramide Accumulation, Promotion of DEVDase Activation in the Absence of Apoptosis, and Augmented Overall Cell Killing.

Separovic D, Saad ZH, Edwin EA, Bielawski J, Pierce JS, Buren EV, Bielawska A - J Lipids (2010)

PDT, with or without LCL30, has no effect on mitochondrial membrane potential or apoptosis. Following incubations, cells were collected and processed for flow cytometry. JC-1 and Annexin V/PI staining were used to detect mitochondrial membrane potential (a) and apoptosis (b), respectively. See Section 2 for other details. (a) Percentage of cells with depolarized mitochondria is shown in lower right dot plot. (b) Percentage of Annexin V (+)/PI (−) and Annexin V (+)/PI (+) is shown in lower right and upper right dot plot, respectively. The representative data for PDT, with or without LCL30, from two independent experiments are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3066794&req=5

fig4: PDT, with or without LCL30, has no effect on mitochondrial membrane potential or apoptosis. Following incubations, cells were collected and processed for flow cytometry. JC-1 and Annexin V/PI staining were used to detect mitochondrial membrane potential (a) and apoptosis (b), respectively. See Section 2 for other details. (a) Percentage of cells with depolarized mitochondria is shown in lower right dot plot. (b) Percentage of Annexin V (+)/PI (−) and Annexin V (+)/PI (+) is shown in lower right and upper right dot plot, respectively. The representative data for PDT, with or without LCL30, from two independent experiments are shown.
Mentions: We have shown that PDT combined with C16-ceramide enhances mitochondrial depolarization in Jurkat cells undergoing apoptosis [36]. Here, we tested whether PDT/LCL30 triggers the collapse of mitochondrial potential in SCCVII cells. As depicted in Figure 4(a), neither individual treatments nor the combination had any effect on mitochondrial membrane potential. In contrast, overnight treatment with camptothecin (5 μM) led to the appearance of 63% cells with depolarized mitochondria.

Bottom Line: Using SCCVII mouse squamous carcinoma cells, and the silicone phthalocyanine Pc 4 for PDT, we showed that combining PDT with LCL30 (PDT/LCL30) was more effective than individual treatments in raising global ceramide levels, as well as in reducing dihydrosphingosine levels.Notably, treatment with the combination resulted in augmented overall cell killing.Our data demonstrate that treatment with PDT/LCL30 leads to enhanced global ceramide levels and DEVDase activation in the absence of apoptosis, and promotion of total cell killing.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48201, USA.

ABSTRACT
Because of the failure of single modality approaches, combination therapy for cancer treatment is a promising alternative. Sphingolipid analogs, with or without anticancer drugs, can improve tumor response. C16-pyridinium ceramide analog LCL30, was used in combination with photodynamic therapy (PDT), an anticancer treatment modality, to test the hypothesis that the combined treatment will trigger changes in the sphingolipid profile and promote cell death. Using SCCVII mouse squamous carcinoma cells, and the silicone phthalocyanine Pc 4 for PDT, we showed that combining PDT with LCL30 (PDT/LCL30) was more effective than individual treatments in raising global ceramide levels, as well as in reducing dihydrosphingosine levels. Unlike LCL30, PDT, alone or combined, increased total dihydroceramide levels. Sphingosine levels were unaffected by LCL30, but were abolished after PDT or the combination. LCL30-triggered rise in sphingosine-1-phosphate was reversed post-PDT or the combination. DEVDase activation was evoked after PDT or LCL30, and was promoted post- PDT/LCL30. Neither mitochondrial depolarization nor apoptosis were observed after any of the treatments. Notably, treatment with the combination resulted in augmented overall cell killing. Our data demonstrate that treatment with PDT/LCL30 leads to enhanced global ceramide levels and DEVDase activation in the absence of apoptosis, and promotion of total cell killing.

No MeSH data available.


Related in: MedlinePlus