Disease relevance of DFFA

• Analyses of apoptotic regulators CASP9 and DFFA at 1P36.2, reveal rare allele variants in human neuroblastoma tumours [1].
• We have studied the presence and functional status of ICAD / DFF in human glioma cell lines [2].
• The present findings suggest that primary brain tumors and normal brain constitutively express ICAD / DFF, and that there is a difference between the expression levels of ICAD-L and ICAD-S [2].
• Several fragments from the C-terminal region of DFF45/ICAD have been cloned and expressed in Escherichia coli as His-tagged proteins [3].
• RESULTS: DFF45 mRNA expression was significantly lower in tumors with higher pathologic stage, higher tumor status (T status), lymph node metastasis, or more extensive lymphatic invasion [4].

High impact information on DFFA

• Furthermore, we demonstrate that the CIDE-N of CIDE-B regulates enzymatic activity of the DFF40/ DFF45 complex in vitro [5].
• The flies deficient in the ICAD gene did not express CAD, and did not undergo apoptotic DNA fragmentation during embryogenesis and oogenesis [6].
• Most importantly, caspase activity results in a selective substrate specificity, since poly(ADP-ribose) polymerase (PARP), lamin B, and Wee1 kinase, but not DNA fragmentation factor (DFF45) or replication factor C (RFC140), are processed [7].
• In this study, we demonstrate caspase-independent and direct cleavage of the 45 kDa unit of DNA fragmentation factor (DFF45) by GrB both in vitro and in vivo [8].
• Staurosporine-induced apoptosis evoked the proteolysis and disappearance of endogenous and exogenous ICAD from the nuclei of HeLa cells, as monitored by immunoblotting and immunofluorescence microscopy [9].

Chemical compound and disease context of DFFA

• This study presents an update contig of the 'Smallest Region of Overlap of deletions' in Scandinavian neuroblastoma tumours and suggests that DFF45 is localized in the region [1].
• This study investigated the expression of DNA fragmentation factor (DFF45), MIB-1, and p53 in formalin-fixed, paraffin-embedded archival tissues of 50 ovarian serous carcinomas [10].

Biological context of DFFA

• PEX14 was the only gene that significantly (p=0.03) reduced cell proliferation for both cell types, DFFA significantly (p=0.04) reduced cell proliferation in SK-N-AS but not in HEK293 cells [11].
• Assignment of the DNA fragmentation factor gene (DFFA) to human chromosome bands 1p36.3-->p36.2 by in situ hybridization [12].
• Here, we examined whether other apoptotic proteinases initiated DNA fragmentation via DFF45/ICAD inactivation [13].
• To resolve this controversy we examined DFF-45/ICAD processing during apoptosis in MCF-7 breast carcinoma cells that lack functional caspase 3 and in MCF-7 cells expressing caspase 3 [14].
• Using bioluminescence resonance energy transfer (BRET), dimerization of ICAD in DFF was confirmed in live cells [15].

Anatomical context of DFFA

• An antiserum against human DFF45 detected 44 and 34 kDa proteins (major and minor, respectively) in the cytosols but not in the nuclear or membrane fractions of various cultured human cells [16].
• The chromosomal DNA in cells expressing caspase-resistant ICAD remained intact after treatment with staurosporine but their chromatin condensed as found in parental Jurkat cells [17].
• Human T-cell lymphoma Jurkat cells, as well as their transformants expressing caspase-resistant ICAD, were treated with staurosporine [17].
• To investigate the mechanism of FAS resistance, the expression of caspase-8 was analysed by immunohistochemistry, together with that of the substrates caspase-3 and ICAD, in 52 representative samples from non Hodgkin's lymphoma (NHL), 12 from Hodgkin's disease (HD), and eight benign lymphoid tissues [18].
• Since ICAD is located in cell nuclei, it is unlikely that the protein functions primarily in the cytoplasm either as an anchor for CAD/CPAN or as a factor that enters the nucleus following caspase cleavage in order to activate resident endonucleases [19].

Associations of DFFA with chemical compounds

• Western blotting was used to measure pro-caspase-9, caspase-3, DFF45, the activated nuclease CPAN and poly (ADP-ribose) polymerase, a DNA repair enzyme inactivated by caspase-3 [20].
• In a clonal derivative of HT29 cells (HT29-Cl.16E cells), ICAD expression was found to be down-regulated during the exponential phase of growth, and the cell death triggered by IFN-gamma, anti-Fas antibody plus Adriamycin was characterized by the expression of early markers of apoptosis, whereas the key nuclear features of apoptosis were absent [21].
• The excision of high molecular weight DNA was inhibited at least 80% in merbarone-treated cells preincubated with the pan-caspase inhibitor z-VAD-fmk [Z-Val-Ala-Asp(OMe)-fluoromethyl ketone] and in caspase-resistant Jurkat cells (ICAD/double-mutated) that express a mutant form of ICAD [22].
• MST1 induced nucleosomal DNA fragmentation, which was suppressed by caspase inhibitors or ICAD (Inhibitor of Caspase-Activated DNase) [23].
• By transcriptional profiling, we identified differentially expressed genes, some of which are involved in cell growth or apoptosis such as inhibitor of caspase-activated DNase (ICAD), defender against cell death 1, tumor necrosis factor (TNF) receptor 1, and cytochrome c oxidase subunit VIII [24].

Regulatory relationships of DFFA

• Purified DFF40 alone possesses intrinsic nuclease activity that is inhibited by its association with DFF45 [25].
• We have assessed the contribution of apoptosis-inducing factor (AIF) and inhibitor of caspase-activated DNase (ICAD) to the nuclear morphology and DNA degradation pattern in staurosporine-induced apoptosis [26].
• Curcumin-induced cleavage of PARP and DFF45 was inhibited by hsp70 but enhanced in Ashsp70 cells [27].

Other interactions of DFFA

• We show that the CIDE-N of CIDE-B interacts with CIDE-N domains of both DFF40 and DFF45 [5].
• In a cell-free assay, caspases-3, -6, -7, -8, and granzyme B initiated benzoyloxycarbonyl-Asp-Glu-Val-Asp (DEVD) cleaving caspase activity, DFF45/ICAD inactivation, and DNA fragmentation, but calpain and cathepsin D failed to initiate these events [13].
• The cell death-inducing DFFA (DNA fragmentation factor-alpha)-like effector A (CIDEA) gene is implicated as an important regulator of body weight in mice and humans and is therefore a candidate gene for human obesity [28].
• The region between the DFF45 and KIF1B genes was defined as homozygous deletion by Southern blotting [29].
• Apoptosis in RCC-91 cells was accompanied by activation of caspases-3 and -9; cleavage of PARP and DFF45 proteins; typical apoptotic nuclei fragmentation and mitochondrial collapse [30].

Analytical, diagnostic and therapeutic context of DFFA

• Moreover, by real-time RT-PCR expression study, we found the mRNA level of DFFA to be significantly (p=0.038) reduced by a factor of 1.7 times in NB tumors of unfavorable outcome [31].
• We have also performed studies of the DFFA expression in tumors using real-time PCR [31].
• Expression, purification, crystallization of fragments from the C-terminal region of DFF45/ICAD [3].
• Allelism tests indicated that resistance genes in SW8 and SW34 may be allelic to H26 and H13 or correspond to paralogs at both loci, respectively [32].
• We reviewed the clinical and radiological findings of 93 consecutive patients with 111 extracranial internal carotid (ICAD) and vertebral artery (VAD) dissections and one concomitant intracranial VAD; 83% of the patients had unilateral and 17% multiple vessel dissections [33].

References