Effect of peritoneal fluid from patients with mild and severe endometriosis on endometrial stromal cell proliferation

Endocrine disruptor hexachlorobenzene induces cell migration and invasion, and enhances aromatase expression levels in human endometrial stromal cells

Endometriosis is the presence and growth of endometrial tissue outside of the uterus. Previous studies have suggested that endocrine disrupting chemicals such as organochlorine pesticides could be a risk factor for endometriosis. Hexachlorobenzene (HCB) is a weak ligand of the aryl hydrocarbon receptor (AhR) and promotes metalloproteinase and cyclooxygenase-2 (COX-2) expression, as well as, c-Src activation in human endometrial stromal cells (T-HESC) and in rat endometriosis model. Our aim was to evaluate the effect of HCB exposure on oestrogen receptor (ER) ɑ and β, progesterone receptor (PR) and aromatase expression, as well as, on cell migration and invasion in T-HESC and primary cultures of endometrial stromal cells from eutopic endometria of control subjects (ESC). Results show that HCB increases ERɑ and aromatase protein levels and reduces PR content in both T-HESC and ESC. However, the pesticide only increases ERβ expression in ESC, without changes in T-HESC. Moreover, cell migration and invasion are promoted by pesticide exposure involving the AhR, c-Src, COX-2 and ER pathways in T-HESC. HCB also triggers ERɑ activation via phosphorylation in Y537 through AhR/c-Src pathway. Our results provide experimental evidence that HCB induces alterations associated with endometriosis, suggesting that these mechanisms could contribute to pesticide exposure-induced endometriosis development.

The role of unfolded protein response in the pathogenesis of endometriosis: contribution of peritoneal fluid

RESEARCH QUESTION

Endoplasmic reticulum stress (ERS) is caused by the accumulation of the misfolded or unfolded proteins in the endoplasmic reticulum and induces the unfolded protein response (UPR). Peritoneal fluid is important in the pathogenesis of endometriosis. In this study, the role of UPR associated with ERS in endometriosis, and peritoneal fluid, were investigated.

DESIGN

Normal, eutopic and ectopic endometrium tissues were divided into menstrual cycle phases, and endometrial stromal cells (ESC) were treated with 10-20% concentration of control peritoneal fluid and peritoneal fluid obtained from women with endometriosis for 10, 30 and 60 min, and 24 and 48 h. The UPR signalling proteins were analysed immunohistochemically and immunocytochemically. Data were compared statistically.

RESULTS

p-IRE1 was increased in ectopic glandular and stromal cells in the early proliferative phase compared with normal and eutopic endometrium. p-PERK increased in ectopic glandular and stromal cells in the late proliferative phase compared with normal endometrium. ATF6 was increased in ectopic glandular epithelium compared with normal endometrium in the proliferative phases, versus eutopic endometrium in the late secretory phase. p-IRE1 and p-PERK were increased in high concentrations of ESC treated with peritoneal fluid obtained from women with endometriosis for 10, 30 and 60 min compared with controls. In ESC treated with peritoneal fluid from women with endometriosis, p-IRE1 decreased at 24-48 h compared with 30 min.

CONCLUSIONS

In endometriosis, UPR pathways are activated as highly dependent on cell type and phase. Also, p-PERK and p-IRE1 increased because of exposure to high-dose peritoneal fluid from women with endometriosis in stromal cells. Our findings provide a basis for further studies searching for a potential biomarker for the diagnosis of endometriosis.

PI3K/AKT pathway is altered in the endometriosis patient's endometrium and presents differences according to severity stage

Based on the inflammatory nature and hormone-dependency of endometriosis, PI3K/AKT signaling appears to influence its progression. Could the endometriosis stages be linked to differential changes in PI3K/AKT pathway regulation? The objective is to evaluate the expression of PI3K, PTEN, AKT and p-AKT in endometrial human biopsies, according to the presence or absence of the disease, and to assess the underlying differences regarding the endometriosis stages. Biopsy specimens of the ectopic and eutopic endometrium were obtained from twenty women with untreated peritoneal endometriosis as well as endometrium biopsies from nine controls. Our study revealed an increased expression of PI3K in eutopic and ectopic endometrium from patients with endometriosis, and a reduced expression of PTEN and increased levels of AKT phosphorylation, compared to control endometrium. Both eutopic and ectopic endometrium from patients with minimal-mild endometriosis expressed a significant reduced PTEN level compared to the respective endometrium from patients with moderate-severe endometriosis. The ratio p-AKT/total AKT showed higher levels of AKT phosphorylation in endometriotic tissue from patients with minimal-mild endometriosis. This study has firmly confirmed the alteration in PI3K/AKT pathway regulation and demonstrated clear differences between the stages of endometriosis, emphasizing the importance of this pathway in the first stage of the disease.

CCL19/CCR7 contributes to the pathogenesis of endometriosis via PI3K/Akt pathway by regulating the proliferation and invasion of ESCs

PROBLEM

The level of CCL19 increased in the peritoneal fluid of women with endometriosis, but the precise mechanism of CCL19/CCR7 in the pathogenesis of endometriosis remains unknown.

METHODS

ELISA and immunohistochemistry were performed to analyze CCL19/CCR7 expressions in peritoneal fluid and endometrium from women with endometriosis (n = 38) and controls (n = 32). Cell proliferation and transwell invasion assays were applied to detect proliferation and invasion of human endometrial stromal cells (ESCs). Expressions of Bcl2, MMP2, MMP9, and p-AKT/AKT were analyzed by Western blot.

RESULTS

Peritoneal fluid concentration of CCL19 in patients with endometriosis was higher than that in controls. Those patients with moderate/severe endometriosis had significantly higher peritoneal fluid concentrations of CCL19 compared to those with minimal/mild endometriosis. Higher CCL19 and CCR7 were found in the endometrium with endometriosis compared to control. CCL19 significantly enhanced ESC proliferation and invasion through CCR7 via activating PI3K/Akt signal pathways. CCL19/CCR7 interaction significantly enhanced phosphorylation of Akt, Bcl2, MMP2, and MMP9 in ESCs.

CONCLUSION

These data indicate CCL19/CCR7 contributes to proliferation and invasion of ESCs, which are conducive to the pathogenesis of endometriosis through activating PI3K/Akt pathway.

Effects of aromatase inhibitors on proliferation and apoptosis in eutopic endometrial cell cultures from patients with endometriosis

OBJECTIVE

To study the effect of letrozole (Let) and anastrozole (Anas) on apoptosis and cell proliferation in epithelial endometrial cells (EEC) from patients with endometriosis (EDT).

DESIGN

Prospective study.

SETTING

Research institute and clinical fertility center.

PATIENT(S)

Eighteen women with untreated EDT.

INTERVENTION(S)

Biopsy specimens of eutopic endometrium were obtained from all subjects. Apoptosis and cell proliferation were examined in EEC after incubation with Let or Anas.

MAIN OUTCOME MEASURE(S)

Percentage of apoptotic cells (ApC) was evaluated by the acridine orange-ethidium bromide technique; cell proliferation was assessed by 3H-thymidine incorporation.

RESULT(S)

Treatment with Let 10 nM and Let 100 nM enhanced values of ApC in cultures from EDT patients. Epithelial endometrial cells treated with Anas 100 nM or Anas 500 nM showed a statistically significant induction on apoptosis levels. Cultures treated with Let 1 nM or Anas 50 nM did not show any significant differences in ApC levels compared with basal conditions. 3H-Thymidine uptake was down regulated by Let 10 nM and Let 100 nM. Similarly, Anas 100 nM and Anas 500 nM showed a significantly lower degree of cell proliferation in EEC. Lower concentrations of Let and Anas did not induce any significant change in cell proliferation rates.

CONCLUSION(S)

Our results show that Let and Anas produced a significant and positive effect on apoptosis and cell proliferation on EEC from EDT patients. These findings support the further investigation of aromatase inhibitors as a treatment option in EDT.

Gonadotropin-releasing hormone agonist induces apoptosis and reduces cell proliferation in eutopic endometrial cultures from women with endometriosis

OBJECTIVE

There is growing evidence that suggests a direct action of gonadotropin-releasing hormone agonist (GnRH-a) on endometrial growth. Consequently, our purpose was to evaluate the effect of GnRH-a on in vitro eutopic endometrial cell growth and apoptosis.

DESIGN

Prospective study.

SETTING

Research institute and clinical fertility center.

PATIENT(S)

Sixteen women with untreated endometriosis and 14 controls.

INTERVENTION(S)

Biopsy specimens of eutopic endometrium were obtained from all subjects. Apoptosis and cell proliferation were examined in epithelial endometrial cell cultures after incubation with leuprolide acetate (LA), antide, and a combination of both.

MAIN OUTCOME MEASURE(S)

The percentage of apoptotic cells was evaluated by the acridine orange-ethidium bromide technique; cell proliferation was assessed by (3)H-thymidine incorporation.

RESULT(S)

Leuprolide acetate (LA) (100 ng/mL) enhanced apoptosis in endometrial cultures from patients with endometriosis and controls, and this effect was reversed by antide 10(-7)M. Cell proliferation was down-regulated by LA at 1, 10, and 100 ng/mL in cultures from women without and with endometriosis. The addition of antide 10(-7)M reversed this inhibition.

CONCLUSION(S)

GnRH-a appears to have a direct effect by enhancing the apoptotic index and decreasing the cell proliferation in endometrial cells.

Oral contraceptives suppress cell proliferation and enhance apoptosis of eutopic endometrial tissue from patients with endometriosis

OBJECTIVE

To evaluate the effects of administering combination oral contraceptives (COCs) to patients with endometriosis on the regulation of cell growth in the eutopic endometrium.

DESIGN

Prospective study.

SETTING

Research institute and clinical fertility center.

PATIENT(S)

Thirteen women with untreated endometriosis and 13 controls.

INTERVENTION(S)

Biopsy specimens of the eutopic endometrium were obtained from all subjects. Apoptosis, cell proliferation, and Bcl-2 and Bax expression were examined at the epithelial and stromal levels in the eutopic endometrium from patients with endometriosis before and after 30 days of daily exposure to COCs and from controls.

MAIN OUTCOME MEASURE(S)

Apoptotic cells were detected by using the dUTP nick-end labeling assay; Ki-67, Bcl-2, and Bax expressions were assessed by using immunohistochemical techniques.

RESULT(S)

After exposure to COCs, apoptosis was significantly increased in the eutopic endometrium compared with before COC administration, both at epithelial and stromal levels. Cell proliferation was significantly lowered by COCs.

CONCLUSION(S)

COCs showed a positive effect on patients with endometriosis by down-regulating cell proliferation and enhancing apoptosis in the eutopic endometrium.

Apoptosis and expression of Bcl-2 and Bax in eutopic endometrium from women with endometriosis

OBJECTIVE

To evaluate and compare spontaneous apoptosis and Bcl-2 and Bax expression in eutopic endometrium from women with and without endometriosis.

DESIGN

Apoptosis and Bcl-2 and Bax expression were examined in eutopic endometrium from women with and without endometriosis.

SETTING

Instituto de Biología y Medicina Experimental-CONICET, Department of Gynecology and Department of Gynecological Pathology, Clínicas University Hospital, Buenos Aires, Argentina.

PATIENT(S)

Women with untreated endometriosis (n = 14) and controls (n = 16).

INTERVENTION(S)

Collection of endometrial samples during diagnostic or therapeutic laparoscopy.

MAIN OUTCOME MEASURE(S)

Apoptotic cells were detected with use of the dUTP nick-end labeling (TUNEL) assay; Bcl-2 and Bax expressions were assessed with use of immunohistochemical techniques.

RESULT(S)

Spontaneous apoptosis was significantly lower in eutopic endometrium from patients with endometriosis, compared with healthy controls (2.26 +/- 0.53 and 9.37 +/- 1.69 apoptotic cells/field, respectively) and was independent of cycle phase. An increased expression of Bcl-2 protein was found in proliferative eutopic endometrium from patients with endometriosis. Bax expression was absent in proliferative endometrium, whereas there was an increase in its expression in secretory endometrium from both patients and controls.

CONCLUSION(S)

Women with endometriosis show decreased number of apoptotic cells in eutopic endometrium. The abnormal survival of endometrial cells may result in their continuing growth into ectopic locations.