ABSTRACT
BACKGROUND: There have been several Radio Frequency (RF) field researches on various populations and groups of different ages in recent years. However, the most important group for research has been declared as the pregnant women and their babies. OBJECTIVE: The aim of the study was to analyse the effect on apoptotic factors of RF fields on newborn rabbit liver tissues. MATERIALS AND METHODS: Cytochrome c and AIF (Apoptosis Inducing Factor) levels were measured by western blot and caspase 1, 3 and 9 activities were measured by colorimetric method. RESULTS: Cytochrome c and AIF levels were not altered, but all caspase activities were increased in female infant rabbits that exposed to 1800 MHz GSM-like RF signals when they reached 1 month of age and caspase 1 and caspase 3 levels were decreased in male infant rabbits that exposed to 1800 MHz GSM-like RF signals between 15th and 22nd days of the gestational period. Results showed that 1800 MHz GSM-like RF exposure might lead to apoptosis in infant rabbit's liver tissues. CONCLUSION: According to the results, we suggest that postnatal RF exposure causes caspase dependent apoptosis in female infant rabbits liver tissues (Tab. 1, Fig. 2, Ref. 27).
Subject(s)
Apoptosis Inducing Factor/radiation effects , Apoptosis/radiation effects , Cytochromes c/radiation effects , Liver/radiation effects , Radio Waves/adverse effects , Animals , Apoptosis Inducing Factor/metabolism , Caspase 1/metabolism , Caspase 3/metabolism , Caspase 9/metabolism , Caspases , Cytochromes c/metabolism , Female , Liver/metabolism , Male , Pregnancy , RabbitsABSTRACT
Glioblastoma is the most common astrocytic brain tumor in humans. Current therapies for this malignancy are mostly ineffective. Photodynamic therapy (PDT), an exciting treatment strategy based on activation of a photosensitizer, has not yet been extensively explored for treating glioblastoma. We used 5-aminolevulinic acid (5-ALA) as a photosensitizer for PDT to induce apoptosis in human malignant glioblastoma U87MG cells and to understand the underlying molecular mechanisms. Trypan blue dye exclusion test showed a decrease in cell viability after exposure to increasing doses of 5-ALA for 4h followed by PDT with a broad spectrum blue light (400-550 nm) at a dose of 18J/cm(2) for 1h and then incubation at 37 degrees C for 4h. Following 0.5 and 1mM 5-ALA-based PDT (5-ALA-PDT), Wright staining and ApopTag assay showed occurrence of apoptosis morphologically and biochemically, respectively. After 5-ALA-PDT, down regulation of nuclear factor kappa B (NFkappaB) and baculovirus inhibitor-of-apoptosis repeat containing-3 (BIRC-3) protein indicated inhibition of survival signals. Besides, 5-ALA-PDT caused increase in Bax:Bcl-2 ratio and mitochondrial release of cytochrome c and apoptosis-inducing factor (AIF). Activation of calpain, caspase-9, and caspase-3 occurred in course of apoptosis. Calpain and caspase-3 activities cleaved alpha-spectrin at specific sites generating 145kD spectrin breakdown product (SBDP) and 120kD SBDP, respectively. The results suggested that 5-ALA-PDT induced apoptosis in U87MG cells by suppression of survival signals and activation of proteolytic pathways. Thus, 5-ALA-PDT can be an effective strategy for inducing apoptosis in glioblastoma.
Subject(s)
Aminolevulinic Acid/pharmacology , Apoptosis/drug effects , Brain Neoplasms/drug therapy , Glioblastoma/drug therapy , Peptide Hydrolases/drug effects , Photochemotherapy/methods , Aminolevulinic Acid/chemistry , Aminolevulinic Acid/therapeutic use , Apoptosis/physiology , Apoptosis/radiation effects , Apoptosis Inducing Factor/drug effects , Apoptosis Inducing Factor/metabolism , Apoptosis Inducing Factor/radiation effects , Apoptosis Regulatory Proteins/antagonists & inhibitors , Apoptosis Regulatory Proteins/metabolism , Apoptosis Regulatory Proteins/radiation effects , Baculoviral IAP Repeat-Containing 3 Protein , Brain Neoplasms/metabolism , Brain Neoplasms/physiopathology , Calpain/drug effects , Calpain/metabolism , Calpain/radiation effects , Caspases/drug effects , Caspases/metabolism , Caspases/radiation effects , Cell Line, Tumor , Cell Survival/drug effects , Cell Survival/physiology , Cell Survival/radiation effects , Dose-Response Relationship, Drug , Glioblastoma/metabolism , Glioblastoma/physiopathology , Humans , Inhibitor of Apoptosis Proteins/drug effects , Inhibitor of Apoptosis Proteins/metabolism , Inhibitor of Apoptosis Proteins/radiation effects , NF-kappa B/drug effects , NF-kappa B/metabolism , NF-kappa B/radiation effects , Peptide Hydrolases/metabolism , Peptide Hydrolases/radiation effects , Ubiquitin-Protein LigasesABSTRACT
AIF is a main mediator of caspase-independent cell death. It is encoded by a single gene located on chromosome X, region q25-26 and A6 in humans and mice, respectively. Previous studies established that AIF codes for two isoforms of the protein, AIF and AIF-exB. Here, we identify a third AIF isoform resulting from an alternate transcriptional start site located at intron 9 of AIF. The resulting mRNA encodes a cytosolic protein that corresponds to the C-terminal domain of AIF (amino acids 353-613). We named this new isoform AIFshort (AIFsh). AIFsh overexpression in HeLa cells results in nuclear translocation and caspase-independent cell death. Once in the nucleus, AIFsh provokes the same effects than AIF, namely chromatin condensation and large scale (50 kb) DNA fragmentation. In contrast, these apoptogenic effects are not precluded by the AIF-inhibiting protein Hsp70. These findings identify AIFsh as a new pro-apoptotic isoform of AIF, and also reveal that the first N-terminal 352 amino acids of AIF are not required for its apoptotic activity. In addition, we demonstrate that AIFsh is strongly down-regulated in tumor cells derived from kidney, vulva, skin, thyroid, and pancreas, whereas, gamma-irradiation treatment provokes AIFsh up-regulation. Overall, our results identify a novel member of the AIF-dependent pathway and shed new light on the role of caspase-independent cell death in tumor formation/suppression.
