DNA fragmentation factor (DFF45): Expression and prognostic value in serous ovarian cancer

Meloxicam Inhibits Apoptosis in Neurons by Deactivating Tumor Necrosis Factor Receptor Superfamily Member 25, Leading to the Decreased Cleavage of DNA Fragmentation Factor Subunit α in Alzheimer's Disease

Neuronal apoptosis is considered to be a critical cause of Alzheimer's disease (AD). Recently, meloxicam has shown neuroprotective effects; however, the inherent mechanisms are highly overlooked. Using APP/PS1 transgenic (Tg) mice as in vivo animal models, we found that meloxicam inhibits apoptosis in neurons by deactivating tumor necrosis factor receptor superfamily member 25 (TNFRSF25), leading to the suppression of the expression of fas-associated protein with death domain (FADD) and the cleavage of DNA fragmentation factor subunit α (DFFA) and cysteine aspartic acid protease-3 (caspase 3) via β-amyloid protein (Aβ)-depressing mechanisms. Moreover, the meloxicam treatment blocked the effects of β-amyloid protein oligomers (Aβo) on stimulating the synthesis of tumor necrosis factor α (TNF-α) and TNF-like ligand 1A (TL1A) in neuroblastoma (N) 2a cells. TNF-α and TL1A induce apoptosis in neurons via TNFR- and TNFRSF25-dependent caspase 3-activating mechanisms, respectively. Knocking down the expression of TNFRSF25 blocked the effects of TL1A on inducing apoptosis in neurons by deactivating the signaling cascades of FADD, caspase 3, and DFFA. Consistently, TNFRSF25 shRNA blocked the effects of Aβo on inducing neuronal apoptosis, which was corroborated by the efficacy of meloxicam in inhibiting Aβo-induced neuronal apoptosis. By ameliorating neuronal apoptosis, meloxicam improved memory loss in APP/PS1 Tg mice.

Insights into molecular pathways of endometriosis and endometriosis-related ovarian carcinoma

Background: Endometriosis is a benign estrogen-dependent gynecological disease involving components of the female genital tract (uterus, Fallopian tubes, ovaries, large, round, and utero-sacral ligaments) and intra- and extraperitoneal regions. Since the moment of its etiopathogeny has been identified, the intrinsic capacity of endometriosis malignant transformation has been hypothesized. Patients,Materials and Methods: Our study included a total number of 50 patients diagnosed with endometriosis (31 cases) and endometriosis-related ovarian carcinoma (EOC) (19 cases). A clinicopathological and immunohistochemical study directed towards the detection of atypical transition lesions and the similitudes in epithelial–mesenchymal transition (EMT) phenomenon [E-cadherin/β-catenin/cytokeratin 18 (CK18)], apoptosis [B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X (Bax)], and hormonal dynamics mirrored by the immunoexpression of estrogen receptor (ER) and progesterone receptor (PR) in endometriosis and EOC glands and stroma has been performed. Results: Our study showed a higher immunoexpression of CK18 and E-cadherin in endometriosis than in neoplastic counterparts, while β-catenin had a stronger immunoexpression in tumors compared with endometriotic areas, with statistically significant differences between the studied groups. Bcl-2/Bax higher rate in endometriosis had a statistically significant association to a more aggressive tumor behavior (p=0.020). ER immunoexpression was stronger in endometriosis, with less negative scores compared to EOC, while PR immunoexpression was stronger in endometriosis, with a lower percent of negative scores compared to EOC. PR immunostaining was correlated to ovarian location of endometriosis (p=0.004) and tumor grade of EOC (p=0.027). Stromal ER and PR immunoexpression has been significantly lower in endometriosis in comparison to tumor stroma (p=0.001) and PR stromal immunoexpression had been higher in more differentiated tumors compared to less differentiated types (p=0.005). Conclusions: Our study supports that endometriosis is a precursor of EOC by the identification and the coexistence of both lesions in the investigated cases, the identification of intermediate lesions, as well as the expression of EMT immunomarkers, along with apoptosis and steroid receptors immunoexpression.

The role of the DFF40/CAD endonuclease in genomic stability

Maintenance of genomic stability in cells is primordial for cellular integrity and protection against tumor progression. Many factors such as ultraviolet light, oxidative stress, exposure to chemical reagents, particularly mutagens and radiation, can alter the integrity of the genome. Thus, human cells are equipped with many mechanisms that prevent these irreversible lesions in the genome, as DNA repair pathways, cell cycle checkpoints, and telomeric function. These mechanisms activate cellular apoptosis to maintain DNA stability. Emerging studies have proposed a new protein in the maintenance of genomic stability: the DNA fragmentation factor (DFF). The DFF40 is an endonuclease responsible of the oligonucleosomal fragmentation of the DNA during apoptosis. The lack of DFF in renal carcinoma cells induces apoptosis without oligonucleosomal fragmentation, which poses a threat to genetic information transfer between cancerous and healthy cells. In this review, we expose the link between the DFF and genomic instability as the source of disease development.

Immunoexpression of DNA fragmentation factor 40, DNA fragmentation factor 45, and B-cell lymphoma 2 protein in normal human endometrium and uterine myometrium depends on menstrual cycle phase and menopausal status

INTRODUCTION

DNA fragmentation factors 40 and 45 (DFF40 and DFF45) are final executors of apoptosis, and B-cell lymphoma 2 (Bcl-2) is a well-recognized apoptosis inhibitor. We aimed to evaluate DFF40, DFF45 and Bcl-2 immunoexpression in the normal human endometrium with respect to the glandular and stromal layer and in uterine myometrium.

MATERIAL AND METHODS

DFF40, DFF45, and Bcl-2 expression was assessed via immunohistochemistry in the endometrium and myometrium collected postmenopausally and premenopausally during the proliferative and secretory phases of the menstrual cycle.

RESULTS

Compared to the myometrium and stroma, endometrial glands showed the highest DFF40 and DFF45 expression in pre- and postmenopausal specimens. DFF45, but not DFF40, glandular expression dependent on menstrual cycle phase and DFF40 and DFF45 scoring was significantly lower in postmenopausal specimens. Significantly higher Bcl-2 expression was observed in proliferative glandular endometrium compared to secretory and postmenopausal specimens. No cycle- or menopause-dependent changes were reported for stromal or myometrial DFF40, DFF45 or Bcl-2 expression. DFF40, DFF45 and Bcl-2 expression was independent of age, age at menarche and menopause, BMI, menstrual cycle and menses lengths, parity and gravidity.

CONCLUSIONS

The study provides important evidence regarding menstrual cycle-dependent changes in the expression of DFF40, DFF45 and Bcl-2 in the normal human endometrium, especially in the glandular layer, and shows that their levels are stable in the normal uterine myometrium.

Evaluation of miRNA-196a2 and apoptosis-related target genes: ANXA1, DFFA and PDCD4 expression in gastrointestinal cancer patients: A pilot study

Previous reports have suggested the significant association of miRNAs aberrant expression with tumor initiation, progression and metastasis in cancer, including gastrointestinal (GI) cancers. The current preliminary study aimed to evaluate the relative expression levels of miR-196a2 and three of its selected apoptosis-related targets; ANXA1, DFFA and PDCD4 in a sample of GI cancer patients. Quantitative real-time PCR for miR-196a2 and its selected mRNA targets, as well as immunohistochemical assay for annexin A1 protein expression were detected in 58 tissues with different GI cancer samples. In addition, correlation with the clinicopathological features and in silico network analysis of the selected molecular markers were analyzed. Stratified analyses by cancer site revealed elevated levels of miR-196a2 and low expression of the selected target genes. Annexin protein expression was positively correlated with its gene expression profile. In colorectal cancer, miR-196a over-expression was negatively correlated with annexin A1 protein expression (r = -0.738, p < 0.001), and both were indicators of unfavorable prognosis in terms of poor differentiation, larger tumor size, and advanced clinical stage. Taken together, aberrant expression of miR-196a2 and the selected apoptosis-related biomarkers might be involved in GI cancer development and progression and could have potential diagnostic and prognostic roles in these types of cancer; particularly colorectal cancer, provided the results experimentally validated and confirmed in larger multi-center studies.

DNA fragmentation factors 40 and 45 (DFF40/DFF45) and B-cell lymphoma 2 (Bcl-2) protein are underexpressed in uterine leiomyosarcomas and may predict survival

OBJECTIVES

DNA fragmentation factors 40 and 45 (DFF40 and DFF45) are responsible for final DNA-laddering during apoptosis, whereas Bcl-2 (B-cell lymphoma 2) is an apoptosis inhibitor. Our aim was to investigate the expression of DFF40, DFF45, and Bcl-2 in uterine leiomyosarcomas (uLMS), leiomyomas (uLM), and the normal myometrium. Furthermore, the correlation between DFF40, DFF45, and Bcl-2 expression and clinicopathological parameters in leiomyosarcomas was assessed. Their prognostic value in disease-free survival (DFS) and overall survival (OS) was also calculated.

MATERIALS AND METHODS

This study included 53 cases of uLMS from patients matched for age and menopausal status with 53 cases of uLM and 53 controls of normal myometrium (uM). Case samples of uterine myometrium from leiomyosarcomas (uLMS-M) and leiomyomas (uLM-M) were also studied. Immunohistochemical scoring was undertaken for DFF40, DFF45, and Bcl-2.

RESULTS

DFF40, DFF45, and Bcl-2 were significantly underexpressed in uLMS compared with uLMS-M and uM. In uLMS samples, no correlation between the analyzed proteins was observed. Negative DFF40 and Bcl-2, but not DFF45, staining was a predictor of poorer DFS and OS in women with uLMS. uLM showed DFF40 and Bcl-2 overexpression compared with uM and uLM-M, with a significant positive correlation between DFF40 and DFF45. No differences in DFF40, DFF45, and Bcl-2 expression were observed between the uLMS-M, uLM-M, and uM samples, with a significant positive correlation between DFF40 and DFF45 expression.

CONCLUSION

DFF40, DFF45, and Bcl-2 are significantly underexpressed in uLMS, but only a lack of DFF40 and Bcl-2 negatively influences DFS and OS. Disruption of DFF40 and DFF45 expression was observed in uLMS, but not in uLM or control and case myometrium; this may play a role in tumor pathogenesis.

Significance of apoptosis related proteins on malignant transformation of ovarian tumors: A comparison between Bcl-2/Bax ratio and p53 immunoreactivity

In this study, we compared the immunoreactivities of Bcl-2, Bax and p53 proteins in ovarian tumors and related the immunohistochemical findings to the histological type of the tumors. Formalin-fixed, paraffin wax-embedded tissue sections from 40 patients who had serous-mucinous borderline tumors and serous-mucinous adenocarcinoma of the ovary (n=10 each) were stained with hematoxylin-eosin (H&E). After histopathological examination, serial sections were stained immunohistochemically with primary antibodies to Bcl-2, Bax and p53 using an avidin-biotin-peroxidase method. A semi-quantitative grading system was used to compare the immunohistochemical staining intensities. The nuclear DNA fragmentation of apoptosis was determined using TUNEL method. As a result of immunohistochemical staining, increased immunoreactivity of Bcl-2 was observed in adenocarcinomas when compared to borderline tumors (P<0.001). Strong immunoreactivity of Bcl-2 and mild immunoreactivities of Bax and p53 were detected in ovarian adenocarcinomas. There were no significant statistical differences in the immunoreactivity of Bax among the histological type of ovarian tumors. Whereas a balance was observed between the immunoreactivities of Bcl-2 and Bax in the borderline cases, and this balance was strongly changed toward the anti-apoptotic Bcl-2 protein in patients with adenocarcinoma. TUNEL staining of sections indicated apoptotic cells in the serous borderline tumors were about 8-fold higher than in the serous adenocarcinoma. The results of this study on apoptosis-related factors might help to develop novel protective and therapeutic approaches, such as isoflavonoids and isothiocyanates, which were associated with decreased Bcl-2/Bax ratio, against the malignant epithelial ovarian tumors.

ICAD deficiency in human colon cancer and predisposition to colon tumorigenesis: linkage to apoptosis resistance and genomic instability

We previously showed that DNA fragmentation factor, which comprises a caspase-3-activated DNase (CAD) and its inhibitor (ICAD), may influence the rate of cell death by generating PARP-1-activating DNA breaks. Here we tested the hypothesis that ICAD-deficient colon epithelial cells exhibiting resistance to death stimuli may accumulate additional genetic modifications, leading to a tumorigenic phenotype. We show that ICAD deficiency may be associated with colon malignancy in humans. Indeed, an examination of ICAD expression using immunohistochemistry in an array of both colon cancer and normal tissues revealed that ICAD expression levels were severely compromised in the cancerous tissues. Upon DNA damage caused by a low dose of irradiation, ICAD cells acquire a tumorigenic phenotype. Colon epithelial cells derived from ICAD mice showed a significant resistance to death induced by the colon carcinogen dimethylhydrazine in vitro and in mice. Such resistance was associated with a decrease in PARP-1 activation. In an animal model of dimethylhydrazine-induced colon tumorigenesis, ICAD^−/− mice developed significantly higher numbers of tumors with markedly larger sizes than the wild-type counterparts. Interestingly, the phenotype of the ICAD^−/− mice was not associated with a significant increase in the precancerous aberrant crypt foci suggesting a potential link to tumor progression rather than initiation. More importantly, ICAD deficiency was associated with severe genomic instability as assessed by array comparative genomic hybridization. Such genomic instability consisted most prominently of amplifications but with sizable deletions as compared to the wild-type counterparts affecting several cancer-related genes including RAF-1, GSN, LMO3, and Fzd6 independently of p53. Altogether, our results present a viable case for the involvement of ICAD deficiency in colon carcinogenesis and show that apoptosis and genomic instability may comprise the means by which such deficiency may contribute to the process of increasing susceptibility to carcinogen-induced tumorigenesis.

Human papillomavirus type 16 E6 protein inhibits DNA fragmentation via interaction with DNA fragmentation factor 40

The E6 oncoprotein of human papillomavirus (HPV) is critical in cervical cancer development. Using the yeast two-hybrid assay, we showed that HPV-16 E6 (16E6) interacts with one of the DNA fragmentation factors (DFFs), DFF40, which mediates DNA degradation during apoptosis. Furthermore, 16E6 interacts with DFF40 through its zinc finger motif 2 and a bridge section linking the two zinc finger motifs. DNA fragmentation assays disclosed that 16E6 binding to DFF40 leads to blockage of DNA cleavage. Our data collectively suggest that suppression of DNA fragmentation through 16E6-DFF40 interaction is a central event promoting tumorigenesis.

DFF45 expression in human endometrium is associated with menstrual cycle phases and decreases after menopause

BACKGROUND

Human endometrium undergoes cyclic structural and functional modifications, and if no conception occurs menstruation is observed as the result of endometrial cell apoptosis via DFF40/DFF45 complex activation. In postmenopausal endometrium, the proliferative potential of endometrial cells is decreased, while their susceptibility to apoptosis increases.

METHODS

The study group comprised 104 nonpregnant adult women (78 of reproductive age and 36 after menopause) with no neoplasm or hormonal treatment during the past 6 months. Immunohistochemistry and Western blot methods were used for DFF45 identification and semiquantitative assessment of its amount.

RESULTS

Significantly more DFF45-positive cells were detected in the endometrial glands compared to stroma, and this pattern was constant throughout the whole menstrual cycle and also present in postmenopausal endometrial species. The lowest mean relative amount of DFF45 was detected in postmenopausal endometrial samples. In women of reproductive age, the highest mean relative amount of DFF45 was identified in an early secretory phase of the menstrual cycle, the lowest median value of the relative amount of DFF45 was observed in the late proliferative phase, and the difference was significant.

CONCLUSION

The DFF45 level in human endometrium corresponds to the respective phase of the menstrual cycle and decreases significantly after menopause.

DFF45 expression in ovarian endometriomas

OBJECTIVE

Endometriosis, defined as a spread of endometrium outside the uterus cavity, affects up to 30% women of reproductive age, with the ovaries being its most common localization. In the ectopic lesions, endometrial cells show abnormal proliferation and impaired apoptosis. The DNA destruction during apoptosis is a direct result of activation of the DFF40/DFF45 complex. DFF40 (DNA fragmentation factor of 40 kDa) is responsible for direct DNA fragmentation while DFF45 (DNA fragmentation factor of 45 kDa) acts not only as a DFF40 inhibitor, but also as its chaperone. Therefore, the presence of DFF45 is required for proper DFF40 synthesis. The aim of this study was to determine the DFF45 level in human ovarian endometriosis.

STUDY DESIGN

The endometriosis samples were collected from 43 affected women, while the 81 normal endometrial specimens were obtained from the control group. Western blot and immunohistochemistry tests were used to determine the DFF45 level in examined tissues.

RESULTS

The expression of DFF45 in normal human endometrium and ovarian endometriosis was confirmed using both the Western blot and the immunohistochemistry tests. In normal eutopic proliferatory endometrium, a lower DFF45 expression was observed compared with secretory endometrium, while no cyclic changes in DFF45 expression were observed in the ovarian endometriomas. In the normal eutopic endometrium, stronger DFF45 staining was noted in the endometrial glands in comparison to the stroma, irrespective of menstrual cycle phase. However, in the ovarian endometriosis no difference between the glandular layer and stroma in DFF45 immunoreactivity was appreciated. The lowest level of DFF45 was observed in ovarian endometriosis when compared with both normal eutopic proliferatory and secretory endometria using the Western blot and immunohistochemistry analysis.

CONCLUSIONS

A decreased level of DFF45 observed in ovarian endometriosis may be a part of an apoptosis-resistant mechanism enhancing the disease progression.

Identification and characterization of the human inhibitor of caspase-activated DNase gene promoter

DNA fragmentation factor is a heterodimer complex of the nuclease CAD and its specific inhibitor ICAD, which can be activated during apoptosis to induce DNA fragmentation. Although ICAD expression levels have been quantified in a variety of human cancer cells, the mechanism of ICAD gene regulation remains unknown. In this study, we identified a 106-bp TATA-less region upstream of the transcription start site as a basal promoter of the human ICAD gene. An E-Box motif, which binds transcription factors of the basic helix-loop-helix/leucine zipper family, is responsible for transcriptional activity, as demonstrated using mutated promoter-reporters. A chromatin immunoprecipitation assay further demonstrated that Myc binds to an endogenous ICAD promoter. The functional importance of Myc in the regulation of ICAD transcription was also demonstrated by knock-down of c-Myc and N-Myc gene expression, as well as their ectopic expression. Structural analysis of the human ICAD promoter and identification of factors which regulate its activity might further our understanding of the biological role of ICAD with respect to regulation of apoptosis and cancer development.

Discovery and application of protein biomarkers for ovarian cancer

PURPOSE OF REVIEW

To review the protein biomarker research field in ovarian cancer, including the discovered new biomarkers, biomarker panels, their potential clinical applications, and suggested strategies for biomarker discovery and development.

RECENT FINDINGS

Ovarian cancer is the fifth leading cause of death from cancer among North American women. Unfortunately, there is currently no reliable circulating biomarker that can detect ovarian cancer in its early stages. The CA125 biomarker is extremely valuable for treatment response monitoring, but its sensitivity is very low for early detection. There is an urgent need to identify new circulating biomarkers/panels of biomarkers that could diagnose ovarian cancer before it becomes clinically detectable and advanced. In the past decade, efforts have accelerated to identify such novel biomarkers/panels of serum and urine biomarkers. A couple of individual biomarkers and biomarker panels have been reported with adaptable sensitivity and specificity range, which might hold great potential to be further validated and developed for diagnosis and prognosis applications and to control ovarian cancer mortality.

SUMMARY

The present review summarizes the main advances in the past year, with the lists of biomarkers/panels, their potential applications, and new strategies/lessons we learned based on the most important work published during this period.