Evaluation of the potential therapeutic effects of a double-stranded RNA mimic complexed with polycations in an experimental mouse model of endometriosis

A Reassessment of the Therapeutic Potential of a Dopamine Receptor 2 Agonist (D2-AG) in Endometriosis by Comparison against a Standardized Antiangiogenic Treatment

Dopamine receptor 2 agonists (D2-ags) have been shown to reduce the size of tumors by targeting aberrant angiogenesis in pathological tissue. Because of this, the use of a D2-ag was inferred for endometriosis treatment. When assayed in mouse models however, D2-ags have been shown to cause a shift of the immature vessels towards a more mature phenotype but not a significant reduction in the amount of vascularization and size of lesions. These has raised concerns on whether the antiangiogenic effects of these compounds confer a therapeutic value for endometriosis. In the belief that antiangiogenic effects of D2-ags in endometriosis were masked due to non-optimal timing of pharmacological interventions, herein we aimed to reassess the antiangiogenic therapeutic potential of D2-ags in vivo by administering compounds at a timeframe in which vessels in the lesions are expected to be more sensitive to antiangiogenic stimuli. To prove our point, immunodeficient (NU/NU) mice were given a D2-ag (cabergoline), anti-VEGF (CBO-P11) or vehicle (saline) compounds (n = 8 per group) starting 5 days after implantation of a fluorescently labeled human lesion. The effects on the size of the implants was estimated by monitoring the extent of fluorescence emitted by the lesion during the three-week treatment period. Subsequently mice were sacrificed and lesions excised and fixed for quantitative immunohistochemical/immunofluorescent analysis of angiogenic parameters. Lesion size, vascular density and innervation were comparable in D2-ag and anti-VEGF groups and significantly decreased when compared to control. These data suggest that D2-ags are as powerful as standard antiangiogenic compounds in interfering with angiogenesis and lesion size. Our preliminary study opens the way to further exploration of the mechanisms beneath the antiangiogenic effects of D2-ags for endometriosis treatment in humans.

miR-202-3p overexpression attenuates endometriosis-like lesions by modulating YAP-dependent transcription of S100A6 in murine models

AIM

Recent evidence has suggested the important implications of microRNAs (miRNAs) in the processes of proliferation and tissue remodeling in endometriosis (EMS). We therefore aim to determine the role of miR-202-3p in the pathophysiology of EMS and its underlying mechanisms.

METHODS

Experimental endometriosis was induced in ovariectomized mice implanted with a slow-release 17-β estradiol capsule. Eutopic endometrial stromal cells (euESCs) were isolated and assayed for proliferative, invasive and apoptotic properties by EdU staining, Transwell assays, and flow cytometry. The invasive and apoptotic features in the endometrium of mice with EMS in vivo were evaluated by using immunohistochemical staining and TUNEL assays.

RESULTS

miR-202-3p was observed to be downregulated in the endometrial tissues of EMS patients. MiR-202-3p was also found to target YAP1 which resulted in reduced euESC proliferation and invasion and increased apoptosis. YAP1 was able to phosphorylated STAT3 which consequently upregulated S100A6 to promote the proliferative and invasive abilities of euESCs. MiR-202-3p was thereby proposed to act as an inhibitor of proliferation and tissue damage in the in vivo setting of EMS, its effects however, were able to be counteracted byS100A6, which reversed the effects of miR-202-3p on tissue injury and cell proliferation.

CONCLUSION

Our data together evidenced that miR-202-3p targeted YAP1 to reduce STAT3-mediated S100A6 whereby preventing the progression of EMS.

Inhibition of KIF20A by BKS0349 reduces endometriotic lesions in a xenograft mouse model

Several studies have suggested a possible etiological association between ovarian endometriosis and ovarian cancer. Evidence has shown that KIF20A overexpression might confer a malignant phenotype to ovarian tumors by promoting proliferation and inhibiting apoptosis. However, no data about the role of KIF20A in endometriosis have been described. In this study, the human endometrium (n = 4) was transfected by mCherry adenovirus and intraperitoneally implanted in mice. Subsequently, mice were divided in three groups (n = 8/group) that were treated with Vehicle, BKS0349 (KIF20A-antagonist) or cabergoline (dopamine receptor agonist) for 21 days. mCherry-labeled endometriotic lesions were monitored over time using the IVIS Imaging System. Mice were sacrificed 72 h after the last administration; proliferation was evaluated by immunohistochemistry and apoptosis by TUNEL. CCND1 gene expression (G1 phase-related gene) was measured by qRT-PCR. A significant reduction in mCherry-fluorescent signal was observed in the BKS0349 group after treatment ended (D24) compared with D0 (P-value = 0.0313). Moreover, the mCherry signal on D24 showed a significant decrease in the BKS0349 group compared with controls (P-value = 0.0303), along with significant size reduction of endometriotic lesions observed in the BKS0349 group compared with control on D24 (P-value = 0.0006). Functional studies showed a significant reduction in proliferating cells in the BKS0349-treated group compared with controls (P-value = 0.0082). In addition, CCND1 expression was decreased in the BKS0349 group compared with control (P-value = 0.049) at D24 and a significant increase in apoptotic cells among endometriotic lesions in BKS0349-treated mice was observed compared with control (P-value = 0.0317). Based on these findings, we concluded that BKS0349 induces apoptosis and inhibits cell proliferation, reducing endometriotic lesion size and suggesting KIF20A inhibition by BKS0349 as a novel therapeutic treatment for endometriosis.

A novel homologous model for noninvasive monitoring of endometriosis progression

To date, several groups have generated homologous models of endometriosis through the implantation of endometrial tissue fluorescently labeled by green fluorescent protein (GFP) or tissue from luciferase-expressing transgenic mice into recipient animals, enabling noninvasive monitoring of lesion signal. These models present an advantage over endpoint models, but some limitations persist; use of transgenic mice is laborious and expensive, and GFP presents poor tissue penetration due to the relatively short emission wavelength. For this reason, a homologous mouse model of endometriosis that allows in vivo monitoring of generated lesions over time and mimics human lesions in recipient mice would be most desirable. In this regard, using C57BL/6 and B6N-Tyrc-Brd/BrdCrCrl mice, we optimized a decidualization protocol to obtain large volumes of decidual endometrium and mimic human lesions. Subsequently, to obtain a more robust and reliable noninvasive monitoring of lesions, we used the fluorescent reporter mCherry, which presents deeper tissue penetration and higher photostability, showing that endometrial tissue was properly labeled with 1 × 108 PFU/mL mCherry adenoviral vectors. mCherry-labeled endometriotic tissue was implanted in recipient mice, generating lesions that displayed characteristics typical of human endometriotic lesions, such as epithelial cells forming glands, local inflammation, collagen deposits, and new vessel formation. In vivo monitoring demonstrated that subcutaneous implantation on ventral abdomen of recipient mice provided the most intense and reliable signal for noninvasive lesion monitoring over a period of at least 20 days. This homologous model improves upon previously reported models of endometriosis and provides opportunities to study mechanism underlying endometriotic lesion growth and progression. We created a cost-effective but accurate homologous mouse model of endometriosis that allows the study of growth and progression of endometriotic lesions over early time points in lesion development through noninvasive monitoring.

Regulation of apoptotic pathways during endometriosis: from the molecular basis to the future perspectives

PURPOSE

Endometriosis is defined as the presence of endometrial-like endometrial cells, glands and stroma outside the uterus, causing a strong inflammatory-like microenvironment in the affected tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease. Considering the pivotal role of interaction between immune and endometriotic cells, in this paper, we aim to shed light about the role of apoptosis pathways in modulating the fine-regulated peritoneal microenvironment during endometriosis.

METHODS

Narrative overview, synthesizing the findings of literature retrieved from searches of computerized databases.

RESULTS

In normal conditions, endometriotic cells, refluxed through the fallopian tubes into the peritoneal cavity, should be attacked and removed by phagocytes and NK cells. During endometriosis, the breakdown of peritoneal homeostasis causes the failure of scavenging mechanisms, allowing the survival of endometriotic cells. The consequent so-called "immunoescaping" of endometriotic cells could be due, at least in part, to the reduction of apoptotic-mediated pathways previously described.

CONCLUSION

Considering the large amount of evidence retrieved from in vitro as well as in vivo models, the reduced apoptosis of endometriotic cells together with the increased apoptosis of peritoneal fluid mononuclear cells may address the peritoneal homeostasis to a permissive environment for the progression of the disease.

Evaluation of the antiproliferative, proapoptotic, and antiangiogenic effects of a double-stranded RNA mimic complexed with polycations in an experimental mouse model of leiomyoma

OBJECTIVE

To assess the antiproliferative, proapoptotic, and antiangiogenic effects of the double-stranded RNA mimic polyinosine-polycytidylic acid (pIC) complexed with polyethylenimine [pIC(PEI)] in xenografted human leiomyomas.

DESIGN

Heterologous leiomyoma mouse model.

SETTING

University-affiliated infertility center.

ANIMAL(S)

Ovariectomized and hormone-replaced nude mice (n = 16) who received human leiomyoma fragment transplantation.

INTERVENTION(S)

Leiomyoma fragments placed in the peritoneum of 5-week-old nude female mice and treated with the vehicle (n = 8) or 0.6 mg/kg [pIC(PEI)] (n = 8) for 4 weeks.

MAIN OUTCOME MEASURE(S)

The size of the leiomyoma implants, and cellular proliferation (Ki67), vascularization (PECAM), and apoptosis (OH-ends) assessed by quantitative immunohistochemical/immunofluorescent analysis of the recovered implants.

RESULT(S)

No significant differences were observed in the size of the leiomyoma implants between groups. Vascularization and proliferation were significantly decreased, and apoptosis was increased in the [pIC(PEI)]-treated group versus control.

CONCLUSION(S)

We hypothesize that the antiangiogenic and apoptotic effects exerted by [pIC(PEI)] might lead to a decrease in lesion size in this animal model if the compound is administered for longer periods of time. This study provides promising data on [pIC(PEI)] as a potential novel therapeutic agent against human leiomyoma.