Activin A increases invasiveness of endometrial cells in an in vitro model of human peritoneum

Endometriosis: Cellular and Molecular Mechanisms Leading to Fibrosis

Endometriosis is a chronic inflammatory condition affecting women of reproductive age. A relevant feature of endometriosis is the presence of fibrotic tissue inside and around the lesions, thus contributing to the classic endometriosis-related symptoms, pain, and infertility. The molecular mechanisms responsible for the development of fibrosis in endometriosis are not yet defined. The present review aimed to examine the biological mechanisms and signalling pathways involved in fibrogenesis of endometriotic lesions, highlighting the difference between deep infiltrating and ovarian endometriosis. The main cell types involved in the development of fibrosis are platelets, myofibroblasts, macrophages, and sensory nerve fibers. Members of the transforming growth factor (TGF) -β family, as well as the receptor Notch, or the bioactive sphingolipid sphingosine 1-phosphate (S1P), play a role in the development of tissue fibrosis, resulting in their metabolism and/or their signalling pathways altered in endometriotic lesions. It is relevant the knowledge of the molecular mechanisms that guide and support fibrosis in endometriosis, to identify new drug targets and provide new therapeutic approaches to patients.

The Complex Roles of Adipokines in Polycystic Ovary Syndrome and Endometriosis

Polycystic ovary syndrome (PCOS) and endometriosis are frequent diseases of the female reproductive tract causing high morbidity as they can significantly affect fertility and quality of life. Adipokines are pleiotropic signaling molecules secreted by white or brown adipose tissues with a central role in energy metabolism. More recently, their involvement in PCOS and endometriosis has been demonstrated. In this review article, we provide an update on the role of adipokines in both diseases and summarize previous findings. We also address the results of multi-omics approaches in adipokine research to examine the role of single nucleotide polymorphisms (SNPs) in genes coding for adipokines and their receptors, the secretome of adipocytes and to identify epigenetic alterations of adipokine genes that might be conferred from mother to child. Finally, we address novel data on the role of brown adipose tissue (BAT), which seems to have notable effects on PCOS. For this review, original research articles on adipokine actions in PCOS and endometriosis are considered, which are listed in the PubMed database.

Endometrial galectin-3 causes endometriosis by supporting eutopic endometrial cell survival and engraftment in the peritoneal cavity

PROBLEM

The pathogenesis of endometriosis remains unclear. Endometrial cells in retrograde menstruation are considered the source of endometriosis; therefore, we hypothesized that the eutopic endometrium may provide clues regarding the pathogenesis. We aimed to clarify the role of eutopic endometrial cells in endometriosis development.

METHOD OF STUDY

Eutopic endometrial tissues were obtained from patients with or without endometriosis, and expression of cell surface molecules in eutopic endometrial stromal cells (ESCs) was evaluated via iTRAQ-based proteomic analysis. Based on the results, we focused on galectin-3. Galectin-3 expression in clinical samples was confirmed by immunohistochemistry and Western blot analysis. The concentration of secreted galectin-3 was measured using enzyme-linked immunosorbent assays. Adhesion and migration of ESCs were evaluated by in vitro adhesion and wound healing assays. The cytotoxicity of natural killer cells was measured via calcein release assays. Cell proliferation was measured using the CyQUANT Cell Proliferation Assay Kit.

RESULTS

iTRAQ analysis revealed that galectin-3 expression was specifically elevated in the ESCs from endometriosis patients. Immunohistochemistry confirmed galectin-3 overexpression in the eutopic endometrium of endometriosis, irrespective of the menstrual phase. Galectin-3 was overexpressed and secreted by the eutopic ESCs from patients with endometriosis compared to that from patients without endometriosis. Galectin-3 expression in ESCs increased adhesion and migration, whereas galectin-3 inhibitors impaired these processes. Galectin-3 reduced the cytotoxicity of natural killer cells toward ESCs, while not affecting cell proliferation.

CONCLUSION

Galectin-3 promotes peritoneal engraftment of ESCs due to impaired immune surveillance in the peritoneal cavity and increases ESCs adhesion and migration to the peritoneum.

Ethanol extract of Ardisiae Japonicae Herba inhibits hepatoma carcinoma cell proliferation in vitro through regulating lipid metabolism

Objective

The aim of this study is to discover the possible working mechanisms of Ardisiae Japonicae Herba (AJH) on hepatoma carcinoma (HCC).

Methods

In this study, ethanol extract of AJH was prepared and used to treat HCC cell in vitro. Furthermore, a genomic wide RNA sequencing (RNA-seq) was performed to screen deregulated genes in HCC cells after the treatment of AJH extract. The gene and protein expression related to lipid metabolism in HCC cells were also investigated to validate the results obtained from RNA-seq.

Results

AJH extract could inhibit HCC cell proliferation in vitro. RNA-seq analysis has identified 1,601 differentially expressed genes (DEGs, fold change ≥ 2.0 or fold change ≤ 0.5, P < 0.05) in HCC after AJH extract treatment, which included 225 up-regulated genes and 1,376 down-regulated genes. KEGG pathway analysis of DEGs demonstrated that lipid metabolism was a potential pathway related to AJH treatment. In agreement with the RNA-seq data, qPCR and Western-blot analysis indicated that expression of genes and proteins related to lipid metabolism (SREBP1, ACC, ACLY and FASN) were significantly down-regulated in AJH treatment group as compared with the control group. Furthermore, AJH extract could also decrease lipid contents and cellular free fatty acid levels in HCC cells.

Conclusion

Ethanol extract of AJH could inhibit HCC cell proliferation in vitro, the possible mechanism may be related to the inhibition of lipid metabolism.

Sphingosine 1-phosphate receptors are dysregulated in endometriosis: possible implication in transforming growth factor β-induced fibrosis

OBJECTIVE

To study the molecular mechanisms involved in the appearance of the fibrotic trait in endometriosis by investigating whether the signaling pathway of the bioactive sphingolipid sphingosine 1-phosphate (S1P) was altered in endometriotic lesions.

DESIGN

Case-control laboratory study.

SETTING

University research institute and university hospital.

PATIENT(S)

A total of 75 women, with and without endometriosis, were included in the study.

INTERVENTIONS(S)

Endometrial samples were obtained from women affected (n = 15 endometrioma [OMA]; n = 30 deep infiltrating endometriosis [DIE]) and not (n = 30) by endometriosis by means of laparoscopic surgery, followed by clinical and imaging investigation and checking for the expression of fibrosis markers and genes implicated in S1P metabolism and signaling by means of real-time polymerase chain reaction.

MAIN OUTCOME MEASURE(S)

The role of the S1P signaling axis in endometriosis-associated fibrosis was studied in vitro, where RNA interference approaches were used to investigate if S1P synthesis by sphingosine kinases (SKs) and specific S1P receptors (S1PRs) are implicated in the profibrotic effect of the cytokine transforming growth factor (TGF) β1.

RESULT(S)

mRNA expression analysis of S1PR demonstrated a deep dysregulation of S1P signaling in endometriosis, characterized by increased expression of fibrosis markers: S1P₁ was transcriptionally more expressed in OMA, and S1P₃ and S1P₅ mRNA levels were significantly augmented in both OMA and DIE. SK1 and its activating protein calcium- and integrin-binding protein 1 (CIB1) were significantly up-regulated in OMA and DIE. A crucial role for the SK/S1PR axis in the profibrotic effect elicited by TGFβ1 was highlighted in vitro.

CONCLUSION(S)

The S1P signaling axis may represent a useful biomarker or innovative pharmacologic target for endometriosis.

Activin and inhibin signaling: From regulation of physiology to involvement in the pathology of the female reproductive system

Activins and inhibins - comprising activin A, B, AB, C and E, and inhibin A and B isoforms - belong to the transforming growth factor beta (TGFβ) superfamily. They regulate several biological processes, including cellular proliferation, differentiation and invasiveness, to enhance the formation and functioning of many human tissues and organs. In this review, we have discussed the role of activin and inhibin signaling in the physiological and female-specific pathological events that occur in the female reproductive system. The up-to-date evidence indicates that these cytokines regulate germ cell development, follicular development, ovulation, uterine receptivity, decidualization and placentation through the activation of several signaling pathways; and that their dysregulated expression is involved in the pathogenesis and pathophysiology of the numerous diseases, including pregnancy complications, that disturb reproduction. Hence, some of the isoforms have been suggested as potential biomarkers and therapeutic targets for the management of some of these diseases. Tackling the research directions highlighted in this review will enhance a detailed comprehension and the clinical utility of these cytokines.

Characterization of Mechanical Signature of Eutopic Endometrial Stromal Cells of Endometriosis Patients

Endometriosis affects 5-10% of women in reproductive age and causes pelvic pain and subfertility. Exact etiology of the disease is unknown. Here, we present a microfluidic platform for characterizing mechanical properties of eutopic endometrial stromal cells of endometriosis patients based on cellular deformability inside narrow microchannels. Primary human endometrial stromal cells were isolated from eutopic endometrium of endometriosis patients (4407 cells, from 7 endometriosis patients) and from disease-free women (4541 cells, from 6 control women) and were pumped through microchannels (formed of polydimethylsiloxane (PDMS) by standard soft lithography, with dimensions of 8 × 20 × 150 μm, as width × height × length) at a constant flow rate of 2 μL/min. High-speed imaging was used to capture videos of cells as they flow inside microchannels, and a computer vision code was used to track cells, measure their area, and calculate the time each cell takes to pass through the microchannel. Compared with their counterparts from control women, eutopic endometrial stromal cells from endometriosis patients showed significantly increased deformation index (1.65 ± 0.2 versus 1.43 ± 0.19, respectively, P value < 0.001), and higher velocity in travelling through narrow microchannels (96.530 ± 0.710 mm/s versus 57.518 ± 0.585 mm/s, respectively, P value < 0.001). The same difference in velocities between the two cell types was maintained after controlling for cell area. Eutopic endometrial stromal cells of endometriosis patients showed a mechanical phenotype characterized by high deformability and reduced stiffness. This mechanical signature can represent basis of a mechanical biomarker of endometriosis.

Activin a promotes myofibroblast differentiation of endometrial mesenchymal stem cells via STAT3-dependent Smad/CTGF pathway

Background

Endometriosis, characterized by the presence of functional endometrial tissues outside the uterus, is one of the most common gynecological disorders. Endometrial mesenchymal stem cells (MSCs) are crucial for the occurrence and development of endometriosis. Ectopic endometrial MSCs exist in the peritoneal cavity. Thus, the bioactive factors in endometriotic peritoneal fluid may regulate the biological behaviors of endometrial MSCs.

Methods

In this study, after assessing the concentration of Activin A in peritoneal fluid using ELISA, we isolated and cultured endometrial MSCs and investigated whether Activin A stimulated endometrial MSCs to differentiate into myofibroblasts and clarified the underlying mechanisms by quantitative real-time PCR, Western blot analysis, immunofluorescent staining, RNA interference and Chromatin immunoprecipitation. We also employed the inhibitors of Activin A to explore the possibility of suppressing the development of fibrosis in endometriosis using primary endometrial MSCs cultures and a mouse model of endometriosis.

Results

Here, we revealed that Activin A significantly elevated in endometriotic peritoneal fluid and activin receptor-like kinase (ALK4), the specific receptor for Activin A, obviously enhanced in ectopic endometrial MSCs compared with eutopic endometrial MSCs from women with or without endometriosis. Next, we found that Activin A drived myofibroblast differentiation of endometrial MSCs, with extremely enhanced expression of connective tissue growth factor (CTGF). CTGF was shown to be required for Activin A-induced expression of ACTA2, COL1A1 and FN1 in endometrial MSCs. CTGF induction by Activin A in endometrial MSCs involved the activation of Smad2/3, as evidenced by the phosphorylation and nuclear translocation of Smad2/3 as well as the binding of Smad2/3 to CTGF promoter. Furthermore, Smad/CTGF pathway in endometrial MSCs required activation of STAT3 while independent of PI3K, JNK and p-38 pathways. In addition, we also demonstrated that inhibition of Activin A pathway impeded myofibroblast differentiation of endometrial MSCs and ameliorated fibrosis in endometriosis mice.

Conclusions

Activin A promotes myofibroblast differentiation of endometrial mesenchymal stem cells via STAT3-dependent Smad/CTGF pathway. The results provided the first evidence that STAT3 acted as a crucial Activin A downstream mediator to regulate CTGF production. Our data may supplement the stem cell theory of endometriosis and provide the experimental basis to treat endometriosis-associated fibrosis by manipulating Activin A signaling.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0361-3) contains supplementary material, which is available to authorized users.

Expression and Role of Peptides, Proteins and Growth Factors in the Pathogenesis of Endometriosis

Growing evidence is demonstrating that several peptides (corticotrophin-releasing factor, urocortins, ghrelin), proteins (leptin, adiponectin) and growth factors (vascular endothelial growth factor; epidermal growth factor family of growth factors and receptors, fibroblast growth factor, insulin like growth factor and insulin like growth factor-binding proteins, transforming growth factor-β and, activin A and related proteins) are expressed in endometriotic implants, and locally play a relevant role in affecting the biological mechanisms leading to endometriosis. They establish a complex network of interactions by which they are therefore able to stimulate angiogenesis, inflammatory cell recruitment and reaction, the growth of endometriotic tissue and its survival through the modulation of the narrow immune system. This review will evaluate the role played by several regulatory peptides, proteins and growth factors in affecting endometrial physiology and the putative mechanisms advocated to explain endometriosis (angiogenesis, cellular and humoral immunity, inflammatory response, endometrial cell proliferation, activation, motility, adhesion and invasion).

Activin B promotes endometrial cancer cell migration by down-regulating E-cadherin via SMAD-independent MEK-ERK1/2-SNAIL signaling

High-risk type II endometrial cancers account for ~30% of cases but ~75% of deaths due, in part, to their tendency to metastasize. Histopathological studies of type II endometrial cancers (non-endometrioid, mostly serous) suggest overproduction of activin B and down-regulation of E-cadherin, both of which are associated with reduced survival. Our previous studies have shown that activin B increases the migration of type II endometrial cancer cell lines. However, little is known about the relationship between activin B signaling and E-cadherin in endometrial cancer. We now demonstrate that activin B treatment significantly decreases E-cadherin expression in both a time- and concentration-dependent manner in KLE and HEC-50 cell lines. Interestingly, these effects were not inhibited by knockdown of SMAD2, SMAD3 or SMAD4. Rather, the suppressive effects of activin B on E-cadherin were mediated by MEK-ERK1/2-induced production of the transcription factor SNAIL. Importantly, activin B-induced cell migration was inhibited by forced-expression of E-cadherin or pre-treatment with the activin/TGF-β type I receptor inhibitor SB431542 or the MEK inhibitor U0126. We have identified a novel SMAD-independent pathway linking enhanced activin B signaling to reduced E-cadherin expression and increased migration in type II endometrial cancer.

Gold Nanoparticle Reprograms Pancreatic Tumor Microenvironment and Inhibits Tumor Growth

Altered tumor microenvironment (TME) arising from a bidirectional crosstalk between the pancreatic cancer cells (PCCs) and the pancreatic stellate cells (PSCs) is implicated in the dismal prognosis in pancreatic ductal adenocarcinoma (PDAC), yet effective strategies to disrupt the crosstalk is lacking. Here, we demonstrate that gold nanoparticles (AuNPs) inhibit proliferation and migration of both PCCs and PSCs by disrupting the bidirectional communication via alteration of the cell secretome. Analyzing the key proteins identified from a functional network of AuNP-altered secretome in PCCs and PSCs, we demonstrate that AuNPs impair secretions of major hub node proteins in both cell types and transform activated PSCs toward a lipid-rich quiescent phenotype. By reducing activation of PSCs, AuNPs inhibit matrix deposition, enhance angiogenesis, and inhibit tumor growth in an orthotopic co-implantation model in vivo. Auto- and heteroregulations of secretory growth factors/cytokines are disrupted by AuNPs resulting in reprogramming of the TME. By utilizing a kinase dead mutant of IRE1-α, we demonstrate that AuNPs alter the cellular secretome through the ER-stress-regulated IRE1-dependent decay pathway (RIDD) and identify endostatin and matrix metalloproteinase 9 as putative RIDD targets. Thus, AuNPs could potentially be utilized as a tool to effectively interrogate bidirectional communications in the tumor microenvironment, reprogram it, and inhibit tumor growth by its therapeutic function.

Activin A Stimulates Aromatase via the ALK4-Smad Pathway in Endometriosis

Endometriosis is an estrogen-dependent disease. We previously found that the expression of Activin A was upregulated in the peritoneal fluid of patients with endometriosis. The results of the present study indicated that Activin A induced estradiol secretion and P450arom expression in endometrial stromal cells (ESCs) derived from endometriosis patients. The mechanism of estrogenic synthesis was regulated by the Activin-Smad pathway in endometrial lesions. The data showed that the effect of Activin A on ESCs was partially abrogated by pretreatment with an inhibitor of ALK4 (the type I receptor, ActRIB) and Smad4-siRNA. Cumulatively, these data suggest that Activin A promotes the secretion of estradiol from ESCs by increasing the expression of P450arom via the ALK4-Smad pathway. These findings indicate the ALK4-Smad pathway may promote ectopic lesion survival and development.

Apoptosis modulation by activin A and follistatin in human endometrial stromal cells

Activin A is a growth factor that stimulates decidualization and is abundantly expressed in endometrial proliferative disorders. Nevertheless, whether it directly affects endometrial cell survival is still unknown. This study investigated the effects of activin A on total death and apoptosis rates and on tumor necrosis factor (TNF) release by human endometrial stromal cells (HESC). We performed a controlled prospective in vitro study using primary HESC cultures obtained from healthy reproductive age women (n = 11). Cells were treated with medium alone (control) or activin A (25 ng/mL) or activin A (25 ng/mL) and its antagonist follistatin (250 ng/mL). Apoptosis and total cell death were measured by flow cytometry, while TNF concentrations in culture media were quantified by ELISA. Activin A decreased the percentage of apoptotic/dead cells from 31% to 22% (p < 0.05, paired t-test) and reduced TNF levels in culture medium by 14%, but there was no linear correlation between TNF release and apoptotic rates. Both effects of activin A were reversed by follistatin. These findings indicate that activin A promotes HESC survival, possibly by a TNF-independent pathway. This mechanism may be critical to the actions of activin A upon stromal cell growth and differentiation in physiology and disease.

Low miR-143/miR-145 Cluster Levels Induce Activin A Overexpression in Oral Squamous Cell Carcinomas, Which Contributes to Poor Prognosis

Deregulated expression of activin A is reported in several tumors, but its biological functions in oral squamous cell carcinoma (OSCC) are unknown. Here, we investigate whether activin A can play a causal role in OSCCs. Activin A expression was assessed by qPCR and immunohistochemistry in OSCC tissues. Low activin A-expressing cells were treated with recombinant activin A and assessed for apoptosis, proliferation, adhesion, migration, invasion and epithelial-mesenchymal transition (EMT). Those phenotypes were also evaluated in high activin A-expressing cells treated with follistatin (an activin A antagonist) or stably expressing shRNA targeting activin A. Transfections of microRNA mimics were performed to determine whether the overexpression of activin A is regulated by miR-143/miR-145 cluster. Activin A was overexpressed in OSCCs in comparison with normal oral mucosa, and high activin A levels were significantly associated with lymph node metastasis, tumor differentiation and poor survival. High activin A levels promoted multiple properties associated with malignant transformation, including decreased apoptosis and increased proliferation, migration, invasion and EMT. Both miR-143 and miR-145 were markedly downregulated in OSCC cell lines and in clinical specimens, and inversely correlated to activin A levels. Forced expression of miR-143 and miR-145 in OSCC cells significantly decreased the expression of activin A. Overexpression of activin A in OSCCs, which is controlled by downregulation of miR-143/miR-145 cluster, regulates apoptosis, proliferation and invasiveness, and it is clinically correlated with lymph node metastasis and poor survival.

Pathogenetic Mechanisms of Deep Infiltrating Endometriosis

Endometriosis is a benign gynecologic disease, affecting women of reproductive age associated with chronic pelvic pain, dysmenorrhea, dyspareunia and infertility. Ovarian endometrioma (OMA), superficial peritoneal endometriosis (SPE), and deep infiltrating endometriosis (DIE) are, till now, recognized as major phenotypes. The discussion is to know whether they share the same pathogenetic mechanisms. Till today, DIE is recognized as the most severe clinical form of endometriosis and has a complex clinical management. The DIE lesions have been considered in the present article, without distinguishing between the anterior (bladder) or the posterior (vagina, uterosacral ligaments, rectum, and ureter) compartment. The present knowledge indicates that hormonal function (estrogen and progesterone receptors) and immunological factors, such as peritoneal macrophages, natural killer cells, and lymphocytes, are critically altered in DIE. The aggressive behavior of DIE may be explained by the highly decreased apoptosis (nuclear factor kappa-light-chain-enhancer of activated B cells [NF-kB], B-cell lymphoma 2 [Blc-2], and anti-Mullerian hormone) and by the increased proliferation activity related to oxidative stress (NF-kB, reactive oxygen species, extracellular regulated kinase (ERK), advanced oxidation protein product). Invasive mechanisms are more expressed (matrix metalloproteinases and activins) in DIE in comparison to the OMA and SPE. Correlated with the increased invasiveness are the data on very high expression of neuroangiogenesis (nerve growth factor, vascular endothelial growth factor, and intercellular adhesion molecule) genes in DIE. Therefore, at the present time, several of the DIE pathogenetic features result specific in comparison to other endometriosis phenotypes, pleading for the existence of a specific entity. These evidence of specific pathogenetic features of DIE may explain the more severe symptomatology related to this form of endometriosis and suggest possible future target medical treatments.

The role of TGFβ superfamily members in the pathophysiology of endometriosis

The transforming growth factor-beta (TGFβ) superfamily comprises over 30 dimeric proteins with conserved structures, which play important roles in the control of cellular proliferation, differentiation and apoptosis. These proteins are expressed and finely regulated in human endometrium during the menstrual cycle, which is consistent with their effects on endometrial cell proliferation and tissue remodeling. This review is focused on summarizing the role of key members of the TGFβ superfamily in the pathophysiology of endometriosis. Evidence suggests that TGFβ, activins, inhibins, nodal, bone morphogenetic proteins, growth differentiation factors, and anti-Müllerian hormone are produced by endometriotic lesions and could be involved in the establishment and progression of the disease. Their receptors and signaling pathways may also be altered in the presence of endometriosis and may be potential targets to the development of therapeutic agents.

Activin A expression in esophageal carcinoma and its association with tumor aggressiveness and differentiation

The aim of the present study was to investigate the expression of activin A in esophageal carcinoma and its association with tumor differentiation and metastasis. A total of 57 esophageal carcinoma patients and 36 controls were included in the current study. The mRNA and protein expression levels of activin A in esophageal tumors or normal esophageal tissues were determined by reverse transcription-quantitative polymerase chain reaction and immunohistochemical analysis. In addition, the association of activin A expression with esophageal carcinoma differentiation, metastasis and recurrence postoperatively was analyzed. The mRNA and protein expression levels of activin A in esophageal carcinoma were significantly higher compared with those in normal esophageal tissues (P<0.05). The expression of activin A was higher in poorly-/moderately-differentiated esophageal tumor tissues compared with that of well-differentiated or control tissues (P<0.05). Furthermore, the expression of activin A in poorly-differentiated esophageal tumor tissues was higher compared with that of moderately-differentiated tissues (P<0.05). A positive correlation was also observed between differentiation degree and activin A expression. The expression of activin A was higher in patients with lymph node metastasis compared with those without metastasis (P<0.05). The cumulative survival rate of patients with a high expression of activin A at 1, 2 and 3 years postoperatively was significantly decreased compared with that of patients with a lower expression of activin A (P<0.05); by contrast, the cumulative recurrence rate was significantly higher in patients with a lower activin A expression (P<0.05). In conclusion, abnormal expression of activin A was detected in esophageal tumor tissues, which was correlated with the tumor differentiation, metastasis, survival and recurrence. In conclusion, activin A may be used as an auxiliary index in the diagnosis and prognosis of clinical esophageal carcinoma.

Role of activins in embryo implantation and diagnosis of ectopic pregnancy: a review

Embryo implantation is a major prerequisite for the successful establishment of pregnancy. Ectopic implantation outside the intrauterine cavity and the development of ectopic pregnancy (EP) is a major cause of maternal morbidity and occasionally mortality during the first trimester. EP may be induced by failure of tubal transport and/or increased tubal receptivity. Activins, their type II receptors and follistatin have been localised in the human endometrial and tubal epithelium and they are major regulators of endometrial and tubal physiology during the menstrual cycle. Pathological expression of activins and their binding protein, follistatin, was observed in tissue and serum samples collected from EP. Several studies with different designs investigated the diagnostic value of a single measurement of serum activin-A in the differentiation between normal intrauterine and failing early pregnancy and the results are controversial. Nevertheless, the diagnostic value of activins in EP, including the other activin isoforms (activin-B and -AB) and follistatin, merits further research. This review appraises the data to date researching the role of activins in the establishment of normal pregnancy and, pathogenesis and diagnosis of tubal EP.

Activin A balance regulates epithelial invasiveness and tumorigenesis

Activin A (Act A) is a member of the TGFβ superfamily. Act A and TGFβ have multiple common downstream targets and have been described to merge in their intracellular signaling cascades and function. We have previously demonstrated that coordinated loss of E-cadherin and TGFβ receptor II (TβRII) results in epithelial cell invasion. When grown in three-dimensional organotypic reconstruct cultures, esophageal keratinocytes expressing dominant-negative mutants of E-cadherin and TβRII showed activated Smad2 in the absence of functional TβRII. However, we could show that increased levels of Act A secretion was able to induce Smad2 phosphorylation. Growth factor secretion can activate autocrine and paracrine signaling, which affects crosstalk between the epithelial compartment and the surrounding microenvironment. We show that treatment with the Act A antagonist Follistatin or with a neutralizing Act A antibody can increase cell invasion in organotypic cultures in a fibroblast- and MMP-dependent manner. Similarly, suppression of Act A with shRNA increases cell invasion and tumorigenesis in vivo. Therefore, we conclude that maintaining a delicate balance of Act A expression is critical for homeostasis in the esophageal microenvironment.

Effects of a novel proteasome inhibitor BU-32 on multiple myeloma cells

Proteasome inhibition is associated with substantial antitumor effects in preclinical models of multiple myeloma (MM) as well as in patients. However, results of recent clinical trials to evaluate the effect of the proteasome inhibitor Bortezomib (Velcade(®), also called PS-341) in MM patients have shown limited activity when used as a single agent. This underscores the need to find new efficacious and less toxic proteasome inhibitors. Recently, carfilzomib was approved for the treatment of refractory/relapsed MM and several new agents have been introduced into the clinic, including marizomib and MLN9708, and trials investigating these second-generation proteasome inhibitors have demonstrated promising results. We have recently synthesized a novel proteasome inhibitor, BU-32, and tested its growth inhibitory effects in different human MM cells including RPMI8226, MM.1S, MM.1R, and U266. In this study, we evaluate the efficacy of the novel proteasome inhibitor BU-32 (NSC D750499) using an in vitro MM model. BU-32 exhibits strong cytotoxicity in a panel of MM cell lines--RPMI8226, MM1S, MM1R, and U266. In addition, we demonstrate by proteasome inhibition assay that BU-32 potently inhibits the chymotryptic- and caspase-like activities of the 26S proteasome. We further show from Annexin V-FITC binding studies that BU-32, like Bortezomib, induces apoptosis in a panel of MM cell lines but the effect is more pronounced with BU-32-treated cells. Invasion assay with the MM.1S cell line indicates that BU-32 inhibits the invasiveness of myeloma cells. Results from our studies using real-time PCR array analyses show that BU-32 effectively downregulates an array of angiogenesis and inflammatory markers. Our results suggest that BU-32 might be a potential chemotherapeutic agent with promising antitumor activity for the treatment of MM.

FOXL2 in human endometrium: hyperexpressed in endometriosis

The present study investigated expression and protein localization of FOXL2 messenger RNA (mRNA) in endometrium of healthy women and in patients with endometriosis during endometrial cycle. In endometriotic lesions, FOXL2 mRNA and protein were evaluated and a possible correlation with activin A mRNA expression changes was also studied. Endometrium was collected from healthy women (n = 52) and from women with endometriosis (n = 31) by hysteroscopy; endometriotic tissues were collected by laparoscopy (n = 38). FOXL2 gene expression analysis in endometrium of healthy women showed a significant expression and no significant changes in mRNA levels between proliferative and secretory phases; a similar pattern was observed in endometrium of patients with endometriosis. Immunohistochemical evaluation showed that FOXL2 protein localized in stromal and glandular cells and colocalized with SUMO-1. FOXL2 mRNA expression was 3-fold higher in endometriosis than in healthy endometrium (P < .01) and a positive correlation between FOXL2 and activin A mRNA was found (P < .05) in endometriosis. In conclusion, FOXL2 mRNA expression and its protein localization do not change during endometrial cycle in eutopic endometrium from healthy individuals or patients with endometriosis; the hyperexpression of FOXL2 in endometriotic lesions suggests an involvement of this transcriptional regulator, probably associated with activin A expression and related to the pathogenesis of endometriosis.

The distinguishing cellular and molecular features of the endometriotic ovarian cyst: from pathophysiology to the potential endometrioma-mediated damage to the ovary

BACKGROUND

Clinical data suggest that the presence of an ovarian endometrioma may cause per se damage to the surrounding otherwise healthy ovarian tissue. However, the basic research has so far done a limited job in trying to understand the potential detrimental effect of an endometrioma presence in the context of the ovarian physiology. We have reviewed the literature with the aim of characterizing the pathophysiology of the endometrioma focusing mostly on factors and mechanisms potentially affecting the surrounding, otherwise normal, ovarian tissue.

METHODS

Comprehensive searches of PUBMED were conducted to identify human studies published from 1991 to 2013 in the English language on the cellular and molecular characterization of the various endometrioma components.

RESULTS

An endometrioma contains free iron, reactive oxygen species (ROS), proteolytic enzymes and inflammatory molecules in concentrations from tens to hundreds of times higher than those present in peripheral blood or in other types of benign cysts. The cyst fluid causes substantial changes in the endometriotic cells that it baths from gene expression modifications to genetic mutations The physical barrier between the cyst contents and the normal ovarian tissue is a thin wall composed of the ovarian cortex itself or fibroreactive tissue. ROS potentially permeating the surrounding tissues and proteolytic substances degrading the adjacent areas are likely to cause the substitution of normal ovarian cortical tissue with fibrous tissue in which the cortex-specific stroma is reduced. The fibrosis is associated with smooth muscle metaplasia and followed by follicular loss and intraovarian vascular injury. Follicular density in tissue surrounding the endometriotic cyst was consistently shown to be significantly lower than in healthy ovaries but this pathological change does not appear to be caused by the stretching of surrounding tissues owing to the presence of a cyst.

CONCLUSIONS

There is sufficient molecular, histological and morphological evidence, in part deriving from knowledge of the pathophysiology, to support a deleterious effect of the endometrioma on the adjacent ovarian cortical tissue, independent of the mere mechanical stretching owing to its size.

The motile and invasive capacity of human endometrial stromal cells: implications for normal and impaired reproductive function

BACKGROUND Mechanisms underlying early reproductive loss in the human are beginning to be elucidated. The migratory and invasive capacity of human endometrial stromal cells (ESCs) is increasingly recognized to contribute to the intense tissue remodelling associated with embryo implantation, trophoblast invasion and endometrial regeneration. In this review, we examine the signals and mechanisms that control ESC migration and invasion and assess how deregulation of these cell functions contributes to common reproductive disorders. METHODS The PubMed database was searched for publications on motility and invasiveness of human ESCs in normal endometrial function and in reproductive disorders including implantation failure, recurrent pregnancy loss (RPL), endometriosis and adenomyosis, covering the period 2000-2012. RESULTS Increasing evidence suggests that implantation failure and RPL involve abnormal migratory responses of decidualizing ESCs to embryo and trophoblast signals. Numerous reports indicate that endometriosis, as well as adenomyosis, is associated with increased basal and stimulated invasiveness of ESCs and their progenitor cells, suggesting a link between a heightened menstrual repair response and the formation of ectopic implants. Migration and invasiveness of ESCs are controlled by a complex array of hormones, growth factors, chemokines and inflammatory mediators, and involve signalling through Rho GTPases, phosphatidylinositol-3-kinase and mitogen-activated protein kinase pathways. CONCLUSIONS Novel concepts are extending our understanding of the key functions of ESCs in effecting tissue repair imposed by cyclic menstruation and parturition. Migration of decidualizing ESCs also serves to support blastocyst implantation and embryo selection through discriminate motile responses directed by embryo quality. Targeting regulatory molecules holds promise for developing new strategies for the treatment of reproductive disorders such as endometriosis and recurrent miscarriage; and harnessing the migratory capacity of progenitor mesenchymal stem cells in the endometrium may offer new opportunities in regenerative medicine.

Cell-extrinsic consequences of epithelial stress: activation of protumorigenic tissue phenotypes

Introduction

Tumors are characterized by alterations in the epithelial and stromal compartments, which both contribute to tumor promotion. However, where, when, and how the tumor stroma develops is still poorly understood. We previously demonstrated that DNA damage or telomere malfunction induces an activin A-dependent epithelial stress response that activates cell-intrinsic and cell-extrinsic consequences in mortal, nontumorigenic human mammary epithelial cells (HMECs and vHMECs). Here we show that this epithelial stress response also induces protumorigenic phenotypes in neighboring primary fibroblasts, recapitulating many of the characteristics associated with formation of the tumor stroma (for example, desmoplasia).

Methods

The contribution of extrinsic and intrinsic DNA damage to acquisition of desmoplastic phenotypes was investigated in primary human mammary fibroblasts (HMFs) co-cultured with vHMECs with telomere malfunction (TRF2-vHMEC) or in HMFs directly treated with DNA-damaging agents, respectively. Fibroblast reprogramming was assessed by monitoring increases in levels of selected protumorigenic molecules with quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, and immunocytochemistry. Dependence of the induced phenotypes on activin A was evaluated by addition of exogenous activin A or activin A silencing. In vitro findings were validated in vivo, in preinvasive ductal carcinoma in situ (DCIS) lesions by using immunohistochemistry and telomere-specific fluorescent in situ hybridization.

Results

HMFs either cocultured with TRF2-vHMEC or directly exposed to exogenous activin A or PGE₂ show increased expression of cytokines and growth factors, deposition of extracellular matrix (ECM) proteins, and a shift toward aerobic glycolysis. In turn, these "activated" fibroblasts secrete factors that promote epithelial cell motility. Interestingly, cell-intrinsic DNA damage in HMFs induces some, but not all, of the molecules induced as a consequence of cell-extrinsic DNA damage. The response to cell-extrinsic DNA damage characterized in vitro is recapitulated in vivo in DCIS lesions, which exhibit telomere loss, heightened DNA damage response, and increased activin A and cyclooxygenase-2 expression. These lesions are surrounded by a stroma characterized by increased expression of α smooth muscle actin and endothelial and immune cell infiltration.

Conclusions

Thus, synergy between stromal and epithelial interactions, even at the initiating stages of carcinogenesis, appears necessary for the acquisition of malignancy and provides novel insights into where, when, and how the tumor stroma develops, allowing new therapeutic strategies.

Raf-1, a potential therapeutic target, mediates early steps in endometriosis lesion development by endometrial epithelial and stromal cells

Endometriosis is a hormone-sensitive gynecological disorder characterized by the benign growth of endometrial-like tissue in the pelvic cavity. Endometriotic lesions composed of endometrial stromal cells (ESC) and glandular epithelial cells (EEC) are thought to arise from menstrual endometrial tissue reaching the pelvic cavity via retrograde menstruation. The cause of endometriotic lesion formation is still not clear. Recent evidence suggest that cytokines may play a role in the early development of endometriosis lesions. Because cytokines and growth factors signal via the v-raf-1 murine leukemia viral oncogene homolog 1 (Raf-1) kinase pathway, we have examined the role of Raf-1 in early steps of endometriosis lesion formation, specifically attachment of endometrial cells to peritoneal mesothelial cells (PMC) and invasion of endometrial cells through PMC (trans-mesothelial invasion). Raf-1 antagonist GW5074 decreased attachment to PMC and trans-mesothelial invasion by primary EEC and ESC. Raf-1 also mediated TGFβ-induced trans-mesothelial invasion by the established, low-invasive EEC line EM42. TGFβ treatment of EEC resulted in Raf-1 phosphorylation at S338 and phosphorylation of ERK, suggesting that TGFβ activates Raf-1 signaling in these cells. GW5074 had little effect on ESC proliferation but inhibited EEC growth significantly under reduced serum conditions. Antagonizing Raf-1 activity and expression via GW5074 and specific Raf-1 small interfering RNA, respectively, did not alter EEC resistance to growth inhibition by TGFβ. Raf-1 inhibition blocked induction of EEC growth by epidermal growth factor. Our data suggest that Raf-1 may mediate pathologic steps involved in early endometriosis lesion formation and may be a mediator of TGFβ and epidermal growth factor actions in endometriosis.

Inflammation: a link between endometriosis and preterm birth

Endometriosis is a chronic inflammatory disease affecting women's health. Pain and infertility are the major symptoms caused by a hormonal/immunological dysfunction, which causes an endometrial impairment. The same pathogenetic mechanisms are also associated with preterm birth: hormones, cytokines, neurohormones, and growth factors interact in modulating extracellular matrix and prostaglandin secretion, thus activating the inflammatory process in placental membranes and myometrium. An overlap of molecules and mechanisms may explain the evidence that preterm birth is a common outcome in pregnant patients with endometriosis.

Inhibition of CD44 N- and O-linked glycosylation decreases endometrial cell lines attachment to peritoneal mesothelial cells

The attachment of endometrial epithelial cells (EECs) and endometrial stromal cells (ESCs) to peritoneal mesothelial cells (PMCs) with and without inhibition of N- and O-linked glycosylation, the viability of EECs and ESCs, and the expression of CD44 surface density were evaluated. Inhibition of CD44 N- and O-linked glycosylation by using tunicamycin and/or B-GalNAc statistically significantly inhibited endometrial cell attachment to peritoneal mesothelial cells, suggesting a role in establishment of early endometriotic lesions.

Induction of endometrial epithelial cell invasion and c-fms expression by transforming growth factor beta

Transforming growth factor beta 1 (TGF-beta1) levels are increased in the peritoneal fluid of endometriosis patients, and endometrial cells express TGF-beta signaling components; however, little is known regarding the role of TGF-beta in endometriosis. Our objective was to examine the effects of TGF-beta1 on (i) the expression of macrophage colony-stimulating factor receptor encoded by the c-fms gene, (ii) transmesothelial invasiveness of endometrial cells, (iii) cellular proliferation and (iv) attachment to peritoneal mesothelial cells (PMCs). Effects of TGF-beta1 on c-fms mRNA expression were determined by real-time RT-PCR and c-fms cell-surface expression by flow cytometry. Effects of TGF-beta1 on the invasiveness of the immortalized endometrial epithelial cell (EEC) line EM42 and primary EECs were examined using a three-dimensional in vitro system modeling the peritoneum. Cellular proliferation and attachment to PMCs were also examined using established techniques. TGF-beta1 had little or no effect on cellular proliferation and endometrial cell attachment to PMCs. TGF-beta1 significantly induced the expression of c-fms mRNA and c-fms cell-surface expression. TGF-beta1 enhanced transmesothelial invasion by EM42 cells and EECs. Antagonists of TGF-beta1 signaling significantly inhibited both the induction of c-fms expression and cellular invasiveness, suggesting that additional studies are warranted to assess the therapeutic potential of TGF-beta antagonists in endometriosis.