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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

Overall cell killing is promoted after (PDT+LCL30). Following the addition of Pc 4 or LCL30, cells were seeded in the growth medium, preincubated overnight, and irradiated with red light (200 mJ/cm2). After eight days of growth at 37°C, colonies (≥50 cells) were stained with crystal violet (0.1%) and counted. The data are expressed as the percentage of killing and are shown as average ± SEM from six to 26 independent determinations. (a) Dose-dependent increase in cell killing after LCL30. The significance (P < .05) is shown as follows: * indicates the significant difference between lower doses (0.1 or 1 μM) and the highest LCL 30 dose (5 μM); ~ indicates the significant difference between 0.1 and 1 μM LCL30. (b) Total cell killing is augmented after (PDT + 1 μM LCL30). The significance (P < .05) is shown as follows: * indicates the significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30); ~ indicates the significant difference between LCL30 and PDT.
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fig6: Overall cell killing is promoted after (PDT+LCL30). Following the addition of Pc 4 or LCL30, cells were seeded in the growth medium, preincubated overnight, and irradiated with red light (200 mJ/cm2). After eight days of growth at 37°C, colonies (≥50 cells) were stained with crystal violet (0.1%) and counted. The data are expressed as the percentage of killing and are shown as average ± SEM from six to 26 independent determinations. (a) Dose-dependent increase in cell killing after LCL30. The significance (P < .05) is shown as follows: * indicates the significant difference between lower doses (0.1 or 1 μM) and the highest LCL 30 dose (5 μM); ~ indicates the significant difference between 0.1 and 1 μM LCL30. (b) Total cell killing is augmented after (PDT + 1 μM LCL30). The significance (P < .05) is shown as follows: * indicates the significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30); ~ indicates the significant difference between LCL30 and PDT.

Mentions: To determine the effect of LCL30 on overall cell killing, clonogenic assay was employed. As shown in Figure 6(a), treatment of SCCVII cells with 0.1, 1 and 5 μM LCL30 led to 7.8, 21.5 and 97.7% cell killing, respectively. The differences between each dose were significant (P < .05), supporting a dose-dependent cell killing after LCL30.


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)

Overall cell killing is promoted after (PDT+LCL30). Following the addition of Pc 4 or LCL30, cells were seeded in the growth medium, preincubated overnight, and irradiated with red light (200 mJ/cm2). After eight days of growth at 37°C, colonies (≥50 cells) were stained with crystal violet (0.1%) and counted. The data are expressed as the percentage of killing and are shown as average ± SEM from six to 26 independent determinations. (a) Dose-dependent increase in cell killing after LCL30. The significance (P < .05) is shown as follows: * indicates the significant difference between lower doses (0.1 or 1 μM) and the highest LCL 30 dose (5 μM); ~ indicates the significant difference between 0.1 and 1 μM LCL30. (b) Total cell killing is augmented after (PDT + 1 μM LCL30). The significance (P < .05) is shown as follows: * indicates the significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30); ~ indicates the significant difference between LCL30 and PDT.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig6: Overall cell killing is promoted after (PDT+LCL30). Following the addition of Pc 4 or LCL30, cells were seeded in the growth medium, preincubated overnight, and irradiated with red light (200 mJ/cm2). After eight days of growth at 37°C, colonies (≥50 cells) were stained with crystal violet (0.1%) and counted. The data are expressed as the percentage of killing and are shown as average ± SEM from six to 26 independent determinations. (a) Dose-dependent increase in cell killing after LCL30. The significance (P < .05) is shown as follows: * indicates the significant difference between lower doses (0.1 or 1 μM) and the highest LCL 30 dose (5 μM); ~ indicates the significant difference between 0.1 and 1 μM LCL30. (b) Total cell killing is augmented after (PDT + 1 μM LCL30). The significance (P < .05) is shown as follows: * indicates the significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30); ~ indicates the significant difference between LCL30 and PDT.
Mentions: To determine the effect of LCL30 on overall cell killing, clonogenic assay was employed. As shown in Figure 6(a), treatment of SCCVII cells with 0.1, 1 and 5 μM LCL30 led to 7.8, 21.5 and 97.7% cell killing, respectively. The differences between each dose were significant (P < .05), supporting a dose-dependent cell killing after LCL30.

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