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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

DEVDase activation is enhanced after (PDT+LCL30). Following incubations (see Figure 2 legend), cells were collected, cell lysates were prepared, and DEVDase activity was measured using DEVD-AMC as the fluorogenic substrate. The data are expressed as fold changes, that is, ratios of treated versus untreated controls and are shown as average ± SEM from four to six independent determinations. The significance (P < .05) is shown by an asterisk indicating significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30).
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fig5: DEVDase activation is enhanced after (PDT+LCL30). Following incubations (see Figure 2 legend), cells were collected, cell lysates were prepared, and DEVDase activity was measured using DEVD-AMC as the fluorogenic substrate. The data are expressed as fold changes, that is, ratios of treated versus untreated controls and are shown as average ± SEM from four to six independent determinations. The significance (P < .05) is shown by an asterisk indicating significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30).

Mentions: Although LCL30 was reported not to induce apoptosis [14], PDT is an effective apoptotic inducer [41]. We used DEVDase assay to assess the activity of caspase-3 as an apoptotic marker. DEVDase was activated 1.47- and 1.95-fold after LCL30 and PDT, respectively (Figure 5). After treatment of SCCVII cells with the combination, a 5.68-fold increase in DEVDase activity was recorded. Therefore, the combined treatment augments the enzyme activity.


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)

DEVDase activation is enhanced after (PDT+LCL30). Following incubations (see Figure 2 legend), cells were collected, cell lysates were prepared, and DEVDase activity was measured using DEVD-AMC as the fluorogenic substrate. The data are expressed as fold changes, that is, ratios of treated versus untreated controls and are shown as average ± SEM from four to six independent determinations. The significance (P < .05) is shown by an asterisk indicating significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig5: DEVDase activation is enhanced after (PDT+LCL30). Following incubations (see Figure 2 legend), cells were collected, cell lysates were prepared, and DEVDase activity was measured using DEVD-AMC as the fluorogenic substrate. The data are expressed as fold changes, that is, ratios of treated versus untreated controls and are shown as average ± SEM from four to six independent determinations. The significance (P < .05) is shown by an asterisk indicating significant difference between an individual treatment, LCL30 or PDT, and the combination (PDT+LCL30).
Mentions: Although LCL30 was reported not to induce apoptosis [14], PDT is an effective apoptotic inducer [41]. We used DEVDase assay to assess the activity of caspase-3 as an apoptotic marker. DEVDase was activated 1.47- and 1.95-fold after LCL30 and PDT, respectively (Figure 5). After treatment of SCCVII cells with the combination, a 5.68-fold increase in DEVDase activity was recorded. Therefore, the combined treatment augments the enzyme activity.

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