Increased concentrations of cathepsin D in peritoneal fluid from women with endometriosis

Cathepsin D non-proteolytically induces proliferation and migration in human omental microvascular endothelial cells via activation of the ERK1/2 and PI3K/AKT pathways

Epithelial ovarian cancer (EOC) frequently metastasises to the omentum, a process that requires pro-angiogenic activation of human omental microvascular endothelial cells (HOMECs) by tumour-secreted factors. We have previously shown that ovarian cancer cells secrete a range of factors that induce pro-angiogenic responses e.g. migration, in HOMECs including the lysosomal protease cathepsin D (CathD). However, the cellular mechanism by which CathD induces these cellular responses is not understood. The aim of this study was to further examine the pro-angiogenic effects of CathD in HOMECs i.e. proliferation and migration, to investigate whether these effects are dependent on CathD catalytic activity and to delineate the intracellular signalling kinases activated by CathD. We report, for the first time, that CathD significantly increases HOMEC proliferation and migration via a non-proteolytic mechanism resulting in activation of ERK1/2 and AKT. These data suggest that EOC cancer secreted CathD acts as an extracellular ligand and may play an important pro-angiogenic, and thus pro-metastatic, role by activating the omental microvasculature during EOC metastasis to the omentum.

Cathepsin Protease Inhibition Reduces Endometriosis Lesion Establishment

Endometriosis is a gynecologic disease characterized by the ectopic presence of endometrial tissue on organs within the peritoneal cavity, causing debilitating abdominal pain and infertility. Current treatments alleviate moderate pain symptoms associated with the disorder but exhibit limited ability to prevent new or recurring lesion establishment and growth. Retrograde menstruation has been implicated for introducing endometrial tissue into the peritoneal cavity, but molecular mechanisms underlying attachment and invasion are not fully understood. We hypothesize that cysteine cathepsins, a group of powerful extracellular matrix proteases, facilitate endometrial tissue invasion and endometriosis lesion establishment in the peritoneal wall and inhibiting this activity would decrease endometriosis lesion implantation. To test this, we used an immunocompetent endometriosis mouse model and found that endometriotic lesions exhibited a greater than 5-fold increase in active cathepsins compared to tissue from peritoneal wall or eutopic endometrium, with cathepsins L and K specifically implicated. Human endometriosis lesions also exhibited greater cathepsin activity than adjacent peritoneum tissue, supporting the mouse results. Finally, we tested the hypothesis that inhibiting cathepsin activity could block endometriosis lesion attachment and implantation in vivo. Intraperitoneal injection of the broad cysteine cathepsin inhibitor, E-64, significantly reduced the number of attached endometriosis lesions in our murine model compared to vehicle-treated controls demonstrating that cathepsin proteases contribute to endometriosis lesion establishment, and their inhibition may provide a novel, nonhormonal therapy for endometriosis.

Cathepsin B in eutopic and ectopic endometrial tissues of patients with endometriosis

This study was performed to investigate the expression of cathepsin B mRNA and protein in eutopic and ectopic endometrial tissues of patients with endometriosis and in normal endometrial tissues and to clarify the association between the cathepsin B expression and endometriosis. A total of 40 women with histologically confirmed endometriosis were recruited for study group. For controls, 20 women undergoing operative treatment for uterine myoma, cervical intraepithelial neoplasia (CIN) or benign gynecologic conditions other than endometriosis were recruited. Eutopic endometrial tissues of both groups and ectopic endometrial tissue of study group were collected during the operations. We employed real time reverse transcriptase - polymerase chain reaction (RT-PCR) to quantify mRNA levels of cathepsin B in these tissues. Then, we performed western blot analysis to measure the protein levels of cathepsin B. The expressions of cathepsin B mRNA and protein were significantly higher in both eutopic and ectopic endometrial tissues of women with endometriosis than in endometrial tissues of controls. These data suggest that the higher expression of cathepsin B in the endometrial tissues might be associated with the development of endometriosis. In addition, eutopic endometrium itself with higher expression cathepsin B may play a pivotal role in the histogenesis of endometriosis.

Determination of cathepsins B, D and G concentration in eutopic proliferative endometrium of women with endometriosis by the surface plasmon resonance imaging (SPRI) technique

OBJECTIVE

To determine the concentrations of cathepsins B, D and G in proliferative eutopic endometrium of patients with and without endometriosis, by use of the surface plasmon resonance imaging (SPRI) technique.

STUDY DESIGN

A total of 55 patients were recruited in the study: 31 patients with endometriosis (stages I-IV) and 24 controls. Endometrial samples were obtained in the first phase of the menstrual cycle from regularly menstruating premenopausal women, prior to laparoscopy, by the use of aspiration biopsy. Endometriosis was appropriately classified according to the Revised American Fertility Society classification and confirmed by histopathology in every case. The SPRI technique was used to determine the concentration of cathepsins B, D and G. To compare the two groups for quantitative data, Mann-Whitney-Wilcoxon's test was used due to the non-normal distribution of the tested variables and normality of distribution was assessed using Shapiro-Wilk W test.

RESULTS

The concentration of the three examined cathepsins was higher in the proliferative eutopic endometrium of patients with endometriosis, especially in advanced stages, e.g. III and IV, when compared to healthy individuals. Corresponding median values were, for cathepsin B: [7.93 pmol/mg (min-max 2.82-15.71) vs 1.2 pmol/mg (min-max 0.7-15.49) p=0.0014], for cathepsin D: [1.86 pmol/mg (min-max 0.51-5.4) vs 1.03 pmol/mg (min-max 0.4-2.72) p=0.00041] and for cathepsin G: [0.6 pmol/mg (min-max 0.33-2.51) vs 0.3 pmol/mg (min-max 0.16-1.29) p=0.00051].

CONCLUSIONS

Increased concentrations of cathepsins B, D and G in the proliferative eutopic endometrium may play a role in the implantation of endometrial tissue outside the uterine cavity.

Immunohistochemical expression of matrix metalloproteinases, their tissue inhibitors, and cathepsin-D in ovarian endometriosis: correlation with severity of disease

In this study the immunohistochemical expression of matrix metalloproteinases 1, 2, 3, and 9, tissue inhibitors (TIMPs) 1 and 2, and cathepsin-D in ovarian endometriomas were correlated with the clinical severity of endometriosis (i.e., presence of chronic pelvic pain [CPP] and American Society of Reproductive Medicine [ASRM] scores). Positive expression of proteases and their inhibitors was found more frequently in cases with low ASRM scores, whereas presence of CPP correlated significantly with absence of expression of TIMPs 1 and 2, indicating, first, that production of these enzymes is more active during the initial phases of the evolution of ovarian endometriosis, declining as fibrosis develops, and second, that expression of TIMPs seems to play a role in the development of CPP.

Serum and endometrial markers

Endometriosis is a benign but aggressive disease. It occurs when shed endometrium from the female reproductive tract grows at a site outside the uterus. The physiological changes in endometriosis-abnormal tissue growth, invasion, and adhesion phenomena-are similar to those seen in tumorous tissues. Although the etiology of endometriosis is not well understood, the disease is widely accepted to result from the ectopic implantation of refluxed menstrual tissues. In addition, immunologic changes, genetic factors, and environmental factors might also affect a woman's susceptibility to develop endometriosis. Thus far, laparoscopic examination is required to confirm the presence of endometriosis; there is no reliable marker for its diagnosis. Many studies are therefore focusing on identifying markers for the diagnosis and follow-up of endometriosis. This chapter provides a systematic review of these studies, including recent findings from our group on the identification of molecules, in serum and/or endometrium, which are associated with the development of endometriosis at different stages. From this research, we hope to be able to suggest how to approach the potential markers. The identification of highly sensitive and specific markers of endometriosis should facilitate the development of accurate and non-invasive techniques for diagnosis and prognosis.

Increased expression of matrix metalloproteinase-9 in the eutopic endometrial tissue of women with endometriosis

BACKGROUND

Endometriosis is a disease where endometrial tissue implants in ectopic locations. Remodelling of the extracellular matrix (ECM) is a prerequisite for the implantation of this tissue to be possible.

METHODS

In this study, we detected immunoreactive matrix metalloproteinase-9 (MMP-9) throughout endometrial tissue and identified von Willebrand factor (vWF)-positive endothelial cells, CD45-positive leukocytes, CD3-positive T lymphocytes and CD68-positive macrophages as cells expressing MMP-9 in the stroma.

RESULTS

We found an increased expression of MMP-9 in the uterine endometrial tissue of women with endometriosis, as assessed by zymography and enzyme-linked immunosorbent assay (ELISA) (P < 0.05). However, RT-PCR did not show a statistically significant increase in MMP-9 mRNA expression in these tissues (P = 0.14). There was no significant difference between women with and without endometriosis in the expression of tissue inhibitor of MMPs (TIMP)-1, a known natural inhibitor of the pro- and active forms of MMP-9, whether tested by ELISA or by RT-PCR (P = 0.46 and 0.37, respectively). Interestingly, the ratio of MMP-9/TIMP-1 expression was significantly higher in women with endometriosis than in normal women both at the protein and the mRNA levels (P < 0.05).

CONCLUSION

These findings make plausible the involvement of MMP-9/TIMP-1 imbalance in the invasiveness of the endometrial tissue of patients with endometriosis and the ectopic development of the disease.

Matrix remodeling and endometriosis

The physiological changes in endometriosis involving multiple steps of matrix remodeling include abnormal tissue growth, invasion, and adhesion formation. Endometriosis-associated abnormal matrix remodeling is affected by several molecular factors including proteolytic enzymes and their inhibitors, which mediate tissue turnover throughout the reproductive tract to maintain the integrity of the endometrium, and ovarian steroids, which normally regulate reconstruction and breakdown of endometrium in the menstrual cycle. In addition, various growth factors, such as platelet-derived growth factor, transform growth factor β, and epidermal growth factor, direct modulation of growth, activation, and chemotaxis which may facilitate endometrial cell adhesion onto the peritoneal mesothelium during the development of endometriosis. Furthermore, cell adhesion molecules are believed to be critically involved in most cellular-level processes including cellular differentiation, motility, and attachment with the extracellular matrix. The present review focuses on the abnormal matrix remodeling process and its possible regulatory mechanism in association with endometriosis development. As a greater understanding of the cause of endometriosis is achieved, better treatment of the disease and its prevention become possible. (Reprod Med Biol 2005; 4: 93-99).

[Cytosolic cathepsin D levels in squamous carcinomas of the lung]

BACKGROUND AND OBJECTIVES

Cathepsin D is an aspartyl proteinase involved in tumoral invasion. The aim of this work was to study cathepsin D cytosolic levels in squamous carcinomas of the lung and their correlation with several clinical and biological parameters.

PATIENTS AND METHOD

The study group included 95 squamous lung carcinomas and 38 normal tissue samples from the same patients. Cathepsin D cytosolic concentrations were determined using an immunoradiometric assay (CIS BioInternational. France). EGFR, erbB2 protein, CD44s, CD44v5 and CD44v6 levels at cell surfaces were determined. The clinical stage, histological grade, ploidy and S-phase cellular fraction (SP) were also considered as variables of the study.

RESULTS

Cathepsin D cytosolic levels oscillated between 7.7 and 576 (median: 38.8) pmol/mg protein and were lower (p = 0.001) than those observed in 38 normal lung samples from the same patients. When tumors were classified according to different clinical and biological parameters, we noticed that cathepsin D levels were higher in carcinomas with lower proliferation rates and no nodal involvement, reaching statistical significance in both cases. Moreover, when lung carcinomas were classified according to cathepsin D concentrations, tumors with higher cathepsin D concentrations had lower EGFR levels (p = 0.011) and small global SP values (p = 0.025) and DNA index (p = 0.023). Likewise, they were found to be CD44s positive more frequently (p = 0.001) and SP positive less frequently (p = 0.022).

CONCLUSIONS

These results lead us to suggest the following: a) in squamous carcinomas of the lung, cathepsin D cytosolic levels are lower than those observed in normal lung samples from the same patients, and b) in this subtype of lung carcinomas, high cathepsin D levels are associated with tumors without nodal involvement, with low proliferation rates, lower EGFR levels, and a reduced positivity for CD44s, pointing to a possible role of this proteinase as a parameter of good outcome.