Abstract | BACKGROUND: AIM: MATERIALS AND METHODS: Following siRNA transfection and PDT treatment, quantitative real-time polymerase chain reaction for quantification of DES mRNA, immunoblotting for protein expression, mass spectrometry for sphingolipid analysis, spectrofluorometry for caspase 3-like ( DEVDase) activity, flow cytometry for apoptosis detection, and trypan blue assay for cell viability evaluation, were performed. RESULTS: Down-regulation of DES led to a substantial increase in levels of dihydroceramides without affecting ceramide levels. PDT-induced accumulation of individual dihydroceramides and global ceramides was increased by DES knockdown. Concomitantly, mitochondrial depolarization, DEVDase activation, late-apoptosis and cell death were attenuated by DES knockdown. Early apoptosis, however, was enhanced. CONCLUSION: Our findings support the following: (i) dihydroceramide reduces pro-apoptotic effects of ceramide; (ii) cells adapt to DES knockdown to become more sensitive to ceramide and early-apoptosis; (iii) DES is a potential molecular target for regulating apoptotic resistance to PDT.
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Authors | Paul Breen, Nicholas Joseph, Kyle Thompson, Jacqueline M Kraveka, Tatyana I Gudz, Li Li, Mehrdad Rahmaniyan, Jacek Bielawski, Jason S Pierce, Eric VAN Buren, Gaurav Bhatti, Duska Separovic |
Journal | Anticancer research
(Anticancer Res)
Vol. 33
Issue 1
Pg. 77-84
(Jan 2013)
ISSN: 1791-7530 [Electronic] Greece |
PMID | 23267130
(Publication Type: Journal Article, Research Support, N.I.H., Extramural)
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Chemical References |
- Ceramides
- Indoles
- RNA, Small Interfering
- Sphingolipids
- dihydroceramide
- phthalocyanine Pc 4
- Oxidoreductases
- dihydroceramide desaturase
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Topics |
- Apoptosis
(drug effects, radiation effects)
- Carcinoma, Squamous Cell
(metabolism, therapy)
- Cell Line, Tumor
- Ceramides
(metabolism, radiation effects)
- Gene Expression Regulation, Neoplastic
(drug effects, radiation effects)
- Head and Neck Neoplasms
(metabolism, therapy)
- Humans
- Indoles
(administration & dosage)
- Molecular Targeted Therapy
- Oxidoreductases
(antagonists & inhibitors, genetics, metabolism)
- Photochemotherapy
- RNA, Small Interfering
- Sphingolipids
(metabolism)
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