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

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.

Pregnancy and the apoptotic pathway in experimental melanoma

Pregnancy-associated melanoma is defined as melanoma diagnosed during pregnancy or within 1 year of delivery. The association of pregnancy with melanoma is well known, but its underlying molecular mechanisms of association are poorly understood. The aim was to assess the expression of apoptosis-related genes in melanoma tumors during pregnancy in an attempt to elucidate the molecular mechanisms underlying apoptosis-driven activation of melanoma cells in this period. Mice were allocated across two experimental groups (nonpregnant and pregnant) and implanted with the melanoma cell line BF16-F10. Tumor tissue was collected for RNA extraction and purification, and gene expression was quantified using the mouse apoptosis RT2ProfilerTM PCR array. Different intracellular apoptotic pathways were activated (positively or negatively) by pregnancy in tumor cells: intrinsic (21.5%), extrinsic (32%), caspase (14%), apoptosis (21.5%), and caspase-activated DNase (11%). The proportion of upregulated genes for each of these pathways was 100, 30, 50, 17, and 0%, respectively. MetaCore software was then used to analyze gene ontology processes and pathways by building networks. Among the gene ontology processes, the majority of differentiated genes were related to the apoptotic process. The main pathway activated by pregnancy was the intrinsic one (genes Api-5, Bcl2-L1, Birc-2, Birc-3, Bok, and Trp53bp2). Pregnancy activates the intrinsic apoptosis pathway to stimulate caspases 7 and 9, but the final balance is inhibition of apoptosis mechanisms. In mice, pregnancy cannot promote or worsen melanoma.

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.

Apoptosis and endometrial receptivity: Relationship with in vitro fertilization treatment outcome

Apoptosis is an important process in the reconstruction of endometrium within the menstrual cycle. The balance between cell proliferation and apoptosis regulates the periodic repair and shedding of endometrial cells and leads to the menstruation or prepare the mucosal layer of endometrium for the implantation of the embryo. Many factors with pro- and antiapoptotic action, such as B cell lymphoma/leukemia-2 and inhibitors apoptosis proteins families, caspases, tumor necrosis factor receptors, phosphatase and tensin homolog, proliferator-activated receptor gamma, microRNAs and others are differently expressed in the endometrial tissue at phases of menstrual cycle. Receptivity of the endometrium at the period of “window of implantation” is associated with the significant increase of apoptosis in endometrium to allow the embryo to be successfully implanted. The impairment of apoptosis regulation in the endometrium at this period often is observed in infertile women with endometriosis, tubal factor, polycystic ovary syndrome, etc.. In many cases the impairment of apoptosis regulation in the endometrium is the main cause of in vitro fertilization (IVF) treatment failure in these patients. As of today, the exact mechanisms and factors mediating the apoptotic process in normal endometrium and in infertile women are not fully understood. Herein, the literature data concerning the endometrial apoptosis regulation in general, and in light of the influence of apoptosis upon IVF treatment outcome are reviewed. The possibility to use some parameters of endometrial apoptosis for prediction of the successful pregnancy achievement in women participating in IVF protocols also is discussed.