Matrix metalloproteinase-26 (matrilysin-2) expression is high in endometrial hyperplasia and decreases with loss of histological differentiation in endometrial cancer

Metalloproteinases in Endometrial Cancer-Are They Worth Measuring?

Endometrial cancer is one of the most common gynecological malignancies, yet the molecular mechanisms that lead to tumor development and progression are still not fully established. Matrix metalloproteinases (MMPs) are a group of enzymes that play an important role in carcinogenesis. They are proteases involved in the degradation of the extracellular matrix (ECM) that surrounds the tumor and the affected tissue allows cell detachment from the primary tumor causing local invasion and metastasis formation. Recent investigations demonstrate significantly increased metalloproteinase and metalloproteinase inhibitor levels in patients with endometrial cancer compared to those with normal endometrium. In this review, we aim to show their clinical significance and possible use in the diagnosis and treatment of patients with endometrial cancer. We have critically summarized and reviewed the research on the role of MMPs in endometrial cancer.

Matrix Metalloproteinases and Their Tissue Inhibitors in Blood Serum of Patients with Endometrial Cancer: Clinical and Morphological Correlations

In patients with endometrial cancer (N=94), endometrial polyps (N=28), endometrial hyperplasia (N=25), and healthy women (N=77), the serum contents of MMP-2, MMP-7, MMP-9, TIMP-1, and TIMP-2 were measured by ELISA. Both carcinoma and benign neoplasms were accompanied by significant elevation of MMP-7 and TIMP-2 in blood serum. The greatest elevation (in comparison with the control) was observed for MMP-7, although serum concentration of this marker was practically identical in patients with carcinoma and benign tumors. In contrast, the levels of MMP-2 and TIMP-1 were lower in cancer patients in comparison with the control; in these patients, the levels of MMP-9 and TIMP-1 were also lower than the corresponding levels in patients with polyps and endometrial hyperplasia. There were no significant correlations between the levels of examined markers with tumor metastasizing, its histological structure, and differentiation degree of endometrial cancer. No differences were observed between examined serological markers in patients with polyps and endometrial hyperplasia of various severities. The examined MMPs and TIMPs cannot be advanced as potential diagnostic markers of endometrial cancer, but they can be used to monitor and prognosticate the disease and to assess effectiveness of the targeted therapy.

Genome-wide association study of serum coenzyme Q10 levels identifies susceptibility loci linked to neuronal diseases

Coenzyme Q₁₀ (CoQ₁₀) is a lipophilic redox molecule that is present in membranes of almost all cells in human tissues. CoQ₁₀ is, amongst other functions, essential for the respiratory transport chain and is a modulator of inflammatory processes and gene expression. Rare monogenetic CoQ₁₀ deficiencies show noticeable symptoms in tissues (e.g. kidney) and cell types (e.g. neurons) with a high energy demand. To identify common genetic variants influencing serum CoQ₁₀ levels, we performed a fixed effects meta-analysis in two independent cross-sectional Northern German cohorts comprising 1300 individuals in total. We identified two genome-wide significant susceptibility loci. The best associated single nucleotide polymorphism (SNP) was rs9952641 (P value = 1.31 × 10 ^-8, β = 0.063, CI_0.95 [0.041, 0.085]) within the COLEC12 gene on chromosome 18. The SNP rs933585 within the NRXN-1 gene on chromosome 2 also showed genome wide significance (P value = 3.64 × 10 ^-8, β = -0.034, CI_0.95 [-0.046, -0.022]). Both genes have been previously linked to neuronal diseases like Alzheimer's disease, autism and schizophrenia. Among our 'top-10' associated variants, four additional loci with known neuronal connections showed suggestive associations with CoQ₁₀ levels. In summary, this study demonstrates that serum CoQ₁₀ levels are associated with common genetic loci that are linked to neuronal diseases.

Estrogen and estrogen receptor induce matrix metalloproteinase-26 expression in endometrial carcinoma cells

The human matrix metalloproteinase (MMP)-26, also called matrilysin-2 or endometase, has been isolated as a matrilysin (MMP-7) homolog. Several reports describe that MMP-26 may be related to the development of endometrial carcinomas. Total RNAs were isolated from 51 normal endometrial tissue samples, 6 endometrial hyperplasia tissue samples and 30 endometrial carcinomas. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate MMP-26 mRNA expression levels. We examined the effect of estrogen and its receptor (ER) on MMP-26 expression in endometrial carcinoma cell lines by real-time RT-PCR, western blot analysis and luciferase assays. To examine protein-DNA binding between ER and MMP-26 promoter, we performed chromatin immunoprecipitation (ChIP) assay. Real-time RT-PCR analysis revealed that MMP-26 mRNA expression was significantly higher in the normal human endometria and hyperplasias compared with that in endometrial carcinomas. Estrogen not only transactivated the MMP-26 promoter activity but also enhanced endogenous MMP-26 expression. The MMP-26 promoter region contains a putative ER response element (ERE). Nuclear ER protein interacted with ERE on the MMP-26 promoter by ChIP assay. We found a significant difference in MMP-26 expression in normal and malignant endometrial tissue samples and that estrogen induced MMP-26 expression. Estrogen may induce endometrial hyperplasia but not endometrial carcinoma. Our results provide evidence that regulation of MMP-26 promoter activity by estrogen may represent a mechanism for endometrial carcinogenesis.

Localization and hormonal regulation of endometrial matrix metalloproteinase-26 in the rhesus macaque

BACKGROUND

The current understanding of hormonal regulation of matrix metalloproteinase-26 (MMP-26) in the primate endometrium is incomplete. The goal of this work was to clarify estrogen and progesterone regulation of MMP-26 in the endometrium of ovariectomized, hormone-treated rhesus macaques.

METHODS

Ovariectomized rhesus macaques (n= 66) were treated with estradiol (E(2)), E(2) plus progesterone, E(2) followed by progesterone alone or no hormone. Endometrium was collected from the hormone-treated animals during the early, mid- and late proliferative and secretory phases of the artificial menstrual cycle. MMP-26 expression was quantified by real-time PCR, and MMP-26 transcript and protein were localized by in situ hybridization and immunohistochemistry and correlated with estrogen receptor 1 and progesterone receptor (PGR).

RESULTS

MMP-26 was localized to glandular epithelium and was undetectable in the endometrial stroma and vasculature. MMP-26 transcript levels were minimal in the hormone-deprived macaques and treatment with E(2) alone did not affect MMP-26 levels. Treatment with progesterone both in the presence and absence of E(2) stimulated MMP-26 expression in the early and mid-secretory phases (P < 0.001). MMP-26 expression preceded decidualization of endometrial stroma. MMP-26 levels then declined to baseline in the late secretory phase (P < 0.01) despite continued E(2) plus progesterone treatment. Loss of detectable MMP-26 expression in the late secretory phase was correlated with late secretory phase loss of glandular epithelial PGR.

CONCLUSIONS

Endometrial MMP-26 expression is dependent on the presence of progesterone in the early secretory phase and then gradually becomes refractory to progesterone stimulation in the late secretory phase. In the macaque, MMP-26 is a marker of the pre-decidual, secretory endometrium. During the second half of the late secretory phase, and during decidualization, MMP-26 loses its response to progesterone concurrent with the loss of epithelial PGR. The decline in MMP-26 levels between the mid- and late secretory phases may play a role in the receptive window for embryo implantation.

Global alteration in gene expression profiles of deciduas from women with idiopathic recurrent pregnancy loss

Recurrent pregnancy loss (RPL) occurs in ∼5% of women. However, the etiology is still poorly understood. Defects in decidualization of the endometrium during early pregnancy contribute to several pregnancy complications, such as pre-eclampsia and intrauterine growth restriction (IUGR), and are believed to be important in the pathogenesis of idiopathic RPL. We performed microarray analysis to identify gene expression alterations in the deciduas of idiopathic RPL patients. Control patients had one antecedent term delivery, but were undergoing dilation and curettage for current aneuploid miscarriage. Gene expression differences were evaluated using both pathway and gene ontology (GO) analysis. Selected genes were validated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). A total of 155 genes were found to be significantly dysregulated in the deciduas of RPL patients (>2-fold change, P < 0.05), with 22 genes up-regulated and 133 genes down-regulated. GO analysis linked a large percentage of genes to discrete biological functions, including immune response (23%), cell signaling (18%) and cell invasion (17.1%), and pathway analysis revealed consistent changes in both the interleukin 1 (IL-1) and IL-8 pathways. All genes in the IL-8 pathway were up-regulated while genes in the IL-1 pathway were down-regulated. Although both pathways can promote inflammation, IL-1 pathway activity is important for normal implantation. Additionally, genes known to be critical for degradation of the extracellular matrix, including matrix metalloproteinase 26 and serine peptidase inhibitor Kazal-type 1, were also highly up-regulated. In this first microarray approach to decidual gene expression in RPL patients, our data suggest that dysregulation of genes associated with cell invasion and immunity may contribute significantly to idiopathic recurrent miscarriage.

Matrix metalloproteinases: protective roles in cancer

The original notion that matrix metalloproteinases (MMPs) act as tumour and metastasis-promoting enzymes by clearing a path for tumour cells to invade and metastasize has been challenged in the last decade. It has become clear that MMPs are involved in numerous steps of tumour progression and metastasis, and hence are now considered to be multifaceted proteases. Moreover, more recent experimental evidence indicates that some members of the MMP family behave as tumour-suppressor enzymes and should therefore be regarded as anti-targets in cancer therapy. The complexity of the pro- and anti-tumorigenic and -metastatic functions might partly explain why broad-spectrum MMP inhibitors failed in phase III clinical trials. This review will provide a focussed overview of the published data on the tumour-suppressive behaviour of MMPs.

Immunohistochemical expression of matrix metalloproteinases in squamous cell carcinoma of the tongue and lower lip

OBJECTIVE

To evaluate the immunohistochemical expression of MMP-1, -2, -7, -9 and -26 in oral squamous cell carcinomas (SCCs) according to tumour site and histological grade of malignancy.

STUDY DESIGN

Fifteen cases of SCC of the lower lip and 15 cases of tongue SCC were selected and divided into low grade malignancy (n = 17) and high grade malignancy (n = 13).

RESULTS

Higher immunohistochemical expression of MMPs by neoplastic cells was observed in tongue SCCs, with a statistically significant difference for MMP-9 (P < 0.05). High-grade SCCs showed a higher expression of MMPs, except for MMP-2, with a statistically significant difference for MMP-7 (P < 0.05) and MMP-26 (P < 0.05). In addition, a direct association was observed between morphological scores of malignancy and MMP immunoreactivity, with the association being significant for MMP-7 and MMP-26.

CONCLUSION

The present results demonstrate the important role of MMPs in the development of SCCs of the lower lip and tongue.

Selected immunohistochemical prognostic factors in endometrial cancer

OBJECTIVE

The objectives of this study were to assess the immunohistochemical expression of p53, bcl-2, c-erbB-2, Ki-67, estrogen (ER) and progesterone (PR) receptors, matrix metalloproteinase-7 and -26 (MMP-7 and MMP-26) in endometrial cancer patients and to assess the relation between steroid receptor positivity and other markers.

DESIGN

Experimental prospective study.

SETTING

Department of Obstetrics and Gynecology, Department of Genetics, Department of Pathology, Palacký University Medical School and University Hospital Olomouc.

METHODS

We studied 144 cases of primary untreated endometrial carcinoma in which the p53, bcl-2, c-erbB-2, Ki-67, ER, PR, MMP-7, and MMP-26 antigens were investigated with the use of immunohistochemical methods. We evaluated the correlations among immunohistochemical staining and the age, International Federation of Gynecology and Obstetrics stage, grading, depth of invasion, and metastatic spread to lymph nodes.

RESULTS

Mean age was 65.7 years (range, 34-90 years). p53, bcl-2, c-erbB-2, Ki-67, ER, and PR were positive in 35 (24.3%), 100 (69.4%), 41 (28.4%), 65 (45.1%), 115 (79.8%), and 127 (88.1%) cases, respectively. Matrix metalloproteinases were evaluated in a group of 70 patients, wherein MMP-7 was positive in 33 patients (47.1%) and MMP-26 was positive in 40 patients (57.1%). The expression of MMP-7 decreased with higher patient age. p53 and Ki-67 overexpression was found to be related to poor differentiation. Immunostaining for bcl-2 correlated with the positivity of steroid receptors status, whereas immunostaining for c-erbB-2 correlated inversely with ER-positive group of cases.

CONCLUSIONS

The overexpression of p53 and Ki-67 seems to indicate a more malignant phenotype, whereas bcl-2 expression in dependence of steroid receptor positivity could contribute to the identification of high-risk tumors.

Expression pattern of matrix metalloproteinases in human gynecological cancer cell lines

Background

Matrix metalloproteinases (MMPs) are involved in the degradation of protein components of the extracellular matrix and thus play an important role in tumor invasion and metastasis. Their expression is related to the progression of gynecological cancers (e.g. endometrial, cervical or ovarian carcinoma). In this study we investigated the expression pattern of the 23 MMPs, currently known in humans, in different gynecological cancer cell lines.

Methods

In total, cell lines from three endometrium carcinomas (Ishikawa, HEC-1-A, AN3 CA), three cervical carcinomas (HeLa, Caski, SiHa), three chorioncarcinomas (JEG, JAR, BeWo), two ovarian cancers (BG-1, OAW-42) and one teratocarcinoma (PA-1) were examined. The expression of MMPs was analyzed by RT-PCR, Western blot and gelatin zymography.

Results

We demonstrated that the cell lines examined can constitutively express a wide variety of MMPs on mRNA and protein level. While MMP-2, -11, -14 and -24 were widely expressed, no expression was seen for MMP-12, -16, -20, -25, -26, -27 in any of the cell lines. A broad range of 16 MMPs could be found in the PA1 cells and thus this cell line could be used as a positive control for general MMP experiments. While the three cervical cancer cell lines expressed 10-14 different MMPs, the median expression in endometrial and choriocarcinoma cells was 7 different enzymes. The two investigated ovarian cancer cell lines showed a distinctive difference in the number of expressed MMPs (2 vs. 10).

Conclusions

Ishikawa, Caski, OAW-42 and BeWo cell lines could be the best choice for all future experiments on MMP regulation and their role in endometrial, cervical, ovarian or choriocarcinoma development, whereas the teratocarcinoma cell line PA1 could be used as a positive control for general MMP experiments.

The links between transcription, beta-catenin/JNK signaling, and carcinogenesis

Interactions between transcription and signaling are fundamentally important for understanding both the structure and function of genetic pathways and their role in diseases such as cancer. The finding that beta-catenin/TCF4 and JNK/c-Jun cooperate has important implications in carcinogenesis. Previously, we found that binding of c-Jun and beta-catenin/TCF4 to the c-jun promoter is dependent upon JNK activity, thus one role for this complex is to contribute to the repression and/or activation of genes that may mediate cell maintenance, proliferation, differentiation, and death, whereas deregulation of these signals may contribute to carcinogenesis. Here we address the functional links reported between activated beta-catenin/JNK signaling pathways, their component genes, and their common targets, and discuss how alterations in the properties of these genes lead to the development of cancer.

Increased expression of matrix metalloproteinases-21 and -26 and TIMP-4 in pancreatic adenocarcinoma

Pancreatic adenocarcinoma is known for early aggressive local invasion, high metastatic potential, and a low 5-year survival rate. Matrix metalloproteinases (MMPs) play important roles in tumor growth and invasion. Earlier studies on pancreatic cancer have found increased expression of certain MMPs to correlate with poorer prognosis, short survival time or presence of metastases. We studied the expression of MMP-21, -26, and tissue inhibitor of matrix metalloproteinases (TIMP)-4 in 50 tissue samples, including 25 adenocarcinomas, seven other malignant pancreatic tumors, and 18 control samples of non-neoplastic pancreatic tissue with immunohistochemistry. The regulation of MMP-21, -26, and TIMP-4 mRNAs by cytokines was studied with RT-PCR in pancreatic cancer cell lines PANC-1, BxPC-3, and AsPC-1. MMP-21, -26, and TIMP-4 were detected in cancer cells in 64, 40, and 60% of tumors, respectively. MMP-21 expressed in well-differentiated cancer cells and occasional fibroblasts, like TIMP-4, tended to diminish in intensity from grade I to grade III tumors. Patients with metastatic lymph nodes had increased expression of MMP-26 in actual tumor samples. All cultured cancer cell lines expressed MMP-21 basally at low levels, and presence of the protein was confirmed immunohistochemically in cultured cells. MMP-21 expression was induced by epidermal growth factor (EGF) in PANC-1 cells. MMP-26 was neither expressed basally nor induced by tumor necrosis factor alpha, transforming growth factor beta-1 (TGFbeta1), EGF, or interferon gamma. Basal TIMP-4 expression was lowest in the poorly differentiated cancer cell line PANC-1 compared to better-differentiated BxPC-3 and AsPC-1 cells. TIMP-4 expression was induced by TGFbeta1 in PANC-1 cells and by EGF in BxPC-3 cells. Our findings suggest that MMP-21 is not a marker of invasiveness, but rather of differentiation, in pancreatic cancer and it may be upregulated by EGF. The putative role of MMP-26 as a marker of metastases warrants further studies. Unlike other TIMPs, TIMP-4 was not upregulated in relation to aggressiveness of pancreatic cancer.

Steroid receptor expression in the vulvar vestibular mucosa — effects of oral contraceptives and menstrual cycle

BACKGROUND

The objective was to evaluate the influence of combined oral contraceptives (COC) and of the menstrual cycle on the steroid receptor expression in the vulvar vestibular mucosa of healthy women.

STUDY DESIGN

Forty-five healthy women (20 with COC and 25 without) were included. Vestibular biopsies were obtained during the menstrual cycle. Estrogen receptors (ER) alpha and beta, progesterone receptors (PR) A and B, glucocorticoid receptor and androgen receptor as well as the proliferation marker Ki67 were analyzed using immunohistochemistry followed by computerized image analysis.

RESULTS

The vestibular stromal tissue of women using COC expressed more ERbeta (p=.024) than that of women without COC. In the follicular phase, PRB was more abundant in the stromal tissue than in the luteal phase (p=.01).

CONCLUSIONS

ERbeta is more abundant in the vulvar vestibular mucosa of women using COC than in that of women without COC. There is a cyclic variation in PRB in the vestibular mucosa in healthy women without COC.

Endometrial expression of the estrogen-sensitive genes MMP-26 and TIMP-4 is altered by a substitution protocol without down-regulation in IVF patients

BACKGROUND

The aim of this study was to analyse the effects of an estradiol (E(2))-progesterone substitution protocol on the endometrial expression of estrogen-sensitive genes during the peri-implantation period.

METHODS

Peripheral blood and endometrial biopsies were obtained from 13 infertile women both in a natural cycle (NC), on days 5 and 7 after ovulation (NC5, NC7), and in an artificial (substituted) cycle (AC), on days 5 and 7 of progesterone addition (AC5, AC7). Estrogen receptor-alpha (ERalpha) and progesterone receptor (PR) were assayed by immunohistochemistry. Matrix metalloproteinase-26 (MMP-26) mRNA and tissue inhibitor of metalloproteinase-4 (TIMP-4) mRNA were semiquantitatively assessed in tissue sections using in situ hybridization (ISH) and quantified in tissue extracts using real-time PCR.

RESULTS

Levels of both E(2) and progesterone were higher in the peripheral blood in AC than in NC. Also on day AC5, expressions of ERalpha, PR and MMP-26 mRNA (focally) were increased in the epithelium and TIMP-4 mRNA in the stroma. Expression levels of these genes dropped significantly between AC5 and AC7, but not between NC5 and NC7. Abnormally high levels in AC5 samples suggest overstimulation with E(2), and the rapid decrease between AC5 and AC7 suggests overstimulation with progesterone.

CONCLUSIONS

In ACs, increased levels of E(2) in the blood exaggerate the endometrial expression of estrogen-sensitive genes, whereas higher levels of progesterone in the blood in the secretory phase exaggerate the drop in expression of these genes. Dramatic variations in the gene expression may not be optimal for the implantation process.

Coordinated peak expression of MMP-26 and TIMP-4 in preinvasive human prostate tumor

The identification of novel biomarkers for early prostate cancer diagnosis is highly important because early detection and treatment are critical for the medical management of patients. Disruption in the continuity of both the basal cell layer and basement membrane is essential for the progression of high-grade prostatic intraepithelial neoplasia (HGPIN) to invasive adenocarcinoma in human prostate. The molecules involved in the conversion to an invasive phenotype are the subject of intense scrutiny. We have previously reported that matrix metalloproteinase-26 (MMP-26) promotes the invasion of human prostate cancer cells via the cleavage of basement membrane proteins and by activating the zymogen form of MMP-9. Furthermore, we have found that tissue inhibitor of metalloproteinases-4 (TIMP-4) is the most potent endogenous inhibitor of MMP-26. Here we demonstrate higher (p<0.0001) MMP-26 and TIMP-4 expression in HGPIN and cancer, compared to non-neoplastic acini. Their expression levels are highest in HGPIN, but decline in invasive cancer (p<0.001 for each) in the same tissues. Immunohistochemical staining of serial prostate cancer tissue sections suggests colocalization of MMP-26 and TIMP-4. The present study indicates that MMP-26 and TIMP-4 may play an integral role during the conversion of HGPIN to invasive cancer and may also serve as markers for early prostate cancer diagnosis.

Mislocalization and unconventional functions of cellular MMPs in cancer

MMPs are multifunctional enzymes capable of targeting the extracellular matrix, growth factors, cytokines and cell surface-associated adhesion and signaling receptors. The cellular localization and the activity of MMPs are tightly controlled at both the transcriptional and the post-transcriptional levels. Mislocalization and presentation in unconventional cellular compartments provide MMPs with an opportunity to cleave previously unidentified proteins. This review is focused on two, entirely different MMPs, one of which is membrane-tethered and another of which is soluble (MT1-MMP and MMP-26, respectively) from twenty four known human MMPs. Our recent studies determined that both of these enzymes functioned at unexpected cellular compartments and it was resulted in the identification of novel proteolytic pathways, whose significance we only partially comprehend as of this writing. It is reasonable, however, to hypothesize from these data that many individual MMPs perform in a similar manner and display a much broader range of functions compared to what we earlier thought.

Estrogen receptor-beta is expressed in stromal cells of fibroadenoma and phyllodes tumors of the breast

An estrogen dependency has been suggested for the growth of fibroadenomas: however, thus far, none of the steroid hormone receptors acting on breast tissues has been demonstrated in the stroma of breast fibroepithelial lesions. In this study, the expression of estrogen receptor (ER)-alpha and -beta was investigated by immunohistochemistry in 33 fibroadenomas and in 30 benign, three borderline and seven malignant phyllodes tumors, all with spindle cell growth and in one distant metastasis. In addition, the presence of ER-beta mRNA and its variants was evaluated by RT-PCR in microdissected stroma. The possible correlation between hormone receptor expression and differentiation processes of stromal cells was investigated by smooth muscle actin and calponin immunostaining. ER-beta was the only hormone receptor expressed by stroma of fibroadenomas and phyllodes tumors, both at protein and mRNA level. The highest percentage of ER-beta was observed in fibroadenomas with cellular stroma and in phyllodes tumors. In both lesions, ER-beta-positive stromal cells showed expression of smooth muscle actin and/or calponin, as demonstrated by double immunostaining. In addition, the mean age at diagnosis was significantly lower in patients with ER-beta-positive vs ER-beta-negative fibroadenomas. In contrast, in phyllodes tumors, ER-beta expression was higher in older patients. In conclusion, (i) only ER-beta is detected in the stroma of fibroadenomas and phyllodes tumors; (ii) its expression correlates with the expression of smooth muscle markers and suggests a role of ER-beta in myofibroblastic differentiation of stromal cells. These two results, together with the young age of patients carrying fibroadenomas with highly ER-beta-positive stroma cells, may further indicate a hormone-receptor mechanism involved in regulating the growth of fibroadenomas. Conversely, the older age of patients with ER-beta-rich phyllodes tumors suggests that mechanisms, probably independent from estrogen stimulation, act on the growth of these tumors.

Reflections on the discovery and significance of estrogen receptor beta

We have known for many years that estrogen is more than the female hormone. It is essential in the male gonads, and in both sexes, estrogen has functions in the skeleton and central nervous system, on behavior, and in the cardiovascular and immune systems. An important aspect of the discovery of estrogen receptor (ER) beta is that the diverse functions of estrogen can now be divided into those mediated by ERalpha and those mediated by ERbeta. Pharmacological exploitation of this division of the labors of estrogen is facilitated by the ligand-binding specificity and selective tissue distribution of the two ERs. Because the ligand binding domains of ERalpha and ERbeta are significantly different from each other, selective ligands can be (and have been) developed to target the estrogenic pathway that is malfunctioning, without interfering with the other estrogen-regulated pathways. Because of the absence of ERbeta from the adult pituitary and endometrium, ERbeta agonists can be used to target ERbeta with no risk of adverse effects from chemical castration and uterine cancer. Some of the diseases in which there is hope that ERbeta agonists will be of benefit are prostate cancer, autoimmune diseases, colon cancer, malignancies of the immune system, and neurodegeneration.

Spatio-Temporal Expression of Matrix Metalloproteinase-26 in Human Placental Trophoblasts and Fetal Red Cells During Normal Placentation1

The processes of implantation and placentation involve the degradation and remodeling of extracellular matrix, cellular proliferation, apoptosis, and differentiation. Evidence indicates that members of the matrix metalloproteinase (MMP) family play crucial roles in these processes. In the present study, we identified the expression and localization of MMP26/endometase/ matrilysin-2 in human placentae at different stages of gestation using methods of reverse transcriptase-polymerase chain reaction, in situ hybridization, and immunohistochemistry. MMP26 was widely localized to villous cytotrophoblast cells, syncytiotrophoblast cells, and to column trophoblasts during early pregnancy. The mRNA and protein level of MMP26 in chorionic villi was highest at Weeks 6-7, and decreased thereafter, reaching its lowest level at the second trimester. The mRNA level was significantly up-regulated in term placenta, while the immunoreactivity remained undetectable. Notably, intense expression of MMP26 was found in fetal nucleated red cells inside the villous capillaries during gestational Weeks 6-9. Strong expression of MMP26 mRNA was also demonstrated in fetal red cells isolated from the whole blood of fetuses at midpregnancy. The expression patterns of MMP26 in human placenta suggests complicated roles for MMP26 during the processes of placentation and hematopoiesis, perhaps working in concert with other members of the MMP family, such as MMP9.

Matrix metalloproteinase-26 is associated with estrogen-dependent malignancies and targets alpha1-antitrypsin serpin

Proteases exert control over cell behavior and affect many biological processes by making proteolytic modification of regulatory proteins. The purpose of this paper is to describe novel, important functions of matrix metalloproteinase (MMP)-26. alpha1-Antitrypsin (AAT) is a serpin, the primary function of which is to regulate the activity of neutrophil/leukocyte elastase. Insufficient antiprotease activity because of AAT deficiency in the lungs is a contributing factor to early-onset emphysema. We recently discovered that AAT is efficiently cleaved by a novel metalloproteinase, MMP-26, which exhibits an unconventional PH(81)CGVPD Cys switch motif and is autocatalytically activated in cells and tissues. An elevated expression of MMP-26 in macrophages and polymorphonuclear leukocytes supports the functional role of MMP-26 in the AAT cleavage and inflammation. We have demonstrated a direct functional link of MMP-26 expression with an estrogen dependency and confirmed the presence of the estrogen-response element in the MMP-26 promoter. Immunostaining of tumor cell lines and biopsy specimen microarrays confirmed the existence of the inverse correlations of MMP-26 and AAT in cells/tissues. An expression of MMP-26 in the estrogen-dependent neoplasms is likely to contribute to the inactivation of AAT, to the follow-up liberation of the Ser protease activity, and because of these biochemical events, to promote matrix destruction and malignant progression. In summary, we hypothesize that MMP-26, by cleaving and inactivating the AAT serpin, operates as a unique functional link that regulates a coordinated interplay between Ser and metalloproteinases in estrogen-dependent neoplasms.