Regulation of MMP-9 (92 kDa type IV collagenase/gelatinase B) expression in stromal cells of human giant cell tumor of bone

Matrix metalloproteinases (MMPs) play an important regulatory role in tissue morphogenesis, cell differentiation, tumor invasion and metastasis. Several authors have reported a direct correlation between the production of 72 kDa (MMP-2) and 92 kDa (MMP-9) type IV collagenases/gelatinases and the metastatic potential of cancer cells. Recently, we have identified the expression of both MMP-2 and MMP-9 in primary cultures of human giant cell tumor (GCT) of bone in vitro, and in tissue extracts in vivo. Interestingly, MMP-9 is not secreted by late-passaged GCT cells. It is possible that the production of MMP-9 is regulated by certain factor(s) secreted by the multinucleated giant cells in the primary culture. In order to test this hypothesis, the effect of primary-culture-conditioned medium on the expression of MMP-9 by late-passaged mononuclear stromal cells was examined. Adding conditioned medium from the primary GCT culture to the late-passaged stromal cells induced MMP-9, as evidenced by the presence of lytic bands at Mr 92000 and 72000 on a gelatin zymogram. These enzyme activities were inhibited by EDTA, a well-known inhibitor of the MMPs. We confirmed these results by Western blotting using specific antibodies and RT-PCR for MMP-2 and MMP-9. Immunofluorescence studies with specific antibodies to MMP-9 further confirmed its expression by the passaged stromal cells cultured in the primary-culture-conditioned medium. The data indicate that MMP-2 and MMP-9 are produced by the mononuclear stromal cells when cultured in GCT primary-culture-conditioned medium. This suggests that multinucleated giant cells in primary cultures secrete a factor(s) that stimulates stromal cells to produce MMP-9, which, in turn, may contribute to the aggressive behavior of GCT.     

Matrix metalloproteinase 9 (gelatinase B) is expressed in multinucleated giant cells of human giant cell tumor of bone and is associated with vascular invasion.

Human giant cell tumor (GCT) consists of multinucleated giant cells and mononuclear stromal cells, and is characterized by frequent vascular invasion without distant metastases. To study the role of matrix metalloproteinases (MMPs) in the vascular invasion, we examined production of MMP-1 (tissue collagenase), -2 (gelatinase A), -3 (stromelysin-1), -9 (gelatinase B), and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in GCT. MMP-9 was highly and predominantly expressed in giant cells by both immunohistochemistry and in situ hybridization. Expression of other MMPs was also observed in some cases but was inconstant. Sandwich enzyme immunoassays demonstrated that MMP-9 is the predominant MMP secreted by GCT. There was a definite imbalance between the amounts of MMP-9 and those of TIMPs in the culture media of GCT, leading to detectable gelatinolytic activity in an assay using 14C-gelatin. Gelatin zymography demonstrated the main activity at about 90 kd, which was identified as the zymogen of MMP-9 by immunoblotting. Immunohistochemistry for type IV collagen and laminin, major basement membrane components, showed that disappearance of the proteins is closely associated with MMP-9-positive giant cells. These results indicate the production of MMP-9 by multinucleated giant cells and suggest that the metalloproteinase may contribute to proteolysis associated with vascular invasion and local bone resorption in human GCT.     

Histogenesis of giant cell tumors

The giant cell tumor of bone (GCT) is a local osteolytic tumor with variable degrees of aggressiveness. In rare cases pulmonary metastases can be observed. The lesion most frequently occurs in the epiphysis of long tubular bones of the knee region, predominantly affecting young adults after closure of the growth plate. The characteristic histological appearance of GCT displays a high number of osteoclast-like multinucleated giant cells, which resulted in the classification "osteoclastoma" or "giant cell tumor". Apart from the multinucleated giant cells, there are two mononuclear cell types in the GCT. The first one has a round morphology and resembles a monocyte. The second cell type is the spindle-shaped, fibroblast-like stromal cell. Cell culture experiments with GCT cells revealed the stromal cell to be the proliferating component of the GCT. The other two cell types, the monocyte and the multinucleated giant cell, were lost after a few cell culture passages. Furthermore, latest results from GCT reveal that the stromal cells secrete a variety of cytokines and differentiation factors, including MCP1, ODF and M-CSF. These molecules are monocyte chemoattractants and are essential for osteoclast differentiation, suggesting that the stromal cell stimulates blood monocyte immigration into tumor tissue and enhances their fusion into osteoclast-like, multinucleated giant cells. The multinucleated giant cell itself demonstrates properties of a normal osteoclast that is able to resorb bone leading to extended osteolysis. This new model of GCT genesis supports the hypothesis that the stromal cell is the neoplastic component whilst the monocytes and the multinucleated giant cells are just a reactive component of this tumor. Taking this into consideration, the nomenclature of the "giant cell tumor" needs to be reconsidered.     

Effect of heat on synthesis of gelatinases and pro-inflammatory cytokines in equine tendinocytes

The aim of this study was to clarify whether matrix metalloproteinases (MMP-2 and -9: gelatinases) and pro-inflammatory cytokines [tumor necrosis factor (TNF) alpha and interleukin (IL)-1beta] are induced by heat in tendon tissue in vitro and to test the hypothesis that heat exposure causes tendinocytes to synthesize pro-inflammatory cytokines and that synthesis of these cytokines, in turn, leads to up-regulation of synthesis of gelatinases. Isolated tendinocytes from equine superficial digital flexor tendons were cultured and all experiments were performed on cells passaged 3 or 4 times. In the cells exposed to heat (37 to 45 degrees C, 0 to 60 min), the survival rate decreased sharply in a temperature- and time-dependent manner, especially at 42 and 45 degrees C. Cells exposed at 40 degrees C, however, showed little change in survival rate and morphology. Gelatin zymograms revealed that proMMP-2 and -9 were the only two MMPs remaining in the supernatant of the cultured tendinocytes, including that of untreated cells. Addition of TNFalpha and IL-1beta to the culture medium of tendinocytes accelerated proMMP-9 synthesis considerably. Heating the tendinocytes (40 degrees C) led to a three-fold increase in proMMP-9 synthesis in a short time. Only TNFalpha was detected in tendinocytes after heat exposure for 30 and 60 min. In contrast, IL-1beta was under the detectable level in ELISA. Cooling of heat-exposed cells from 40 degrees C to 37 degrees C considerably down-regulated cellular proMMP-9 synthesis. Furthermore, proMMP-9 level was greatly reduced in cells treated at lower temperatures, 20 degrees C and 5 degrees C. These findings support our hypothesis that hyperthermia in the horse tendon induces tendinocytes to synthesize pro-inflammatory cytokines and that the synthesis of these cytokines results in the up-regulation of gelatinases.     

骨巨细胞瘤TIMP-3启动子甲基化的研究

目的 检测骨巨细胞瘤(GCT)中TIMP—3启动子甲基化及其蛋白表达，探讨该肿瘤组织TIMP—3蛋白表达缺失的原因和TIMP-3启动子甲基化与GCT分级和复发的关系。方法 用免疫组织化学SP法和蛋白免疫印迹检测TIMP—3在GCT组织中的表达，用甲基化特异的PCR(MSP)法检测TIMP—3基因启动子的甲基化状态。结果 TIMP—3主要在单核基质细胞和多核巨细胞的胞质表达，后者的表达具有明显的极向性。17例GCT中有5例(29．4％)TIMP—3蛋白丢失，其中4例的TIMP—3启动子发生异常甲基化，且均为组织学分级为Ⅱ级的病例。结论 GCT的局部骨质破坏，可能与TIMP—3丢失有关；而TIMP—3启动子的异常甲基化，是TIMP—3基因失活和蛋白丢失的重要机制。     

Hepatic giant cell carcinoma. An ultrastructural and immunohistochemical study

Hepatocellular carcinoma with osteoclast-like giant cells (hepatic giant cell carcinoma [HGCC]) is a rare entity, with only three cases reported. The tumor is histologically similar to giant cell tumor (GCT) of bone, and the origin of the multinucleated giant cells and mononuclear stromal cells has not been determined. The purpose of this report is to present a case of this rare tumor and compare its ultrastructural and immunohistochemical features with those of a conventional GCT of bone. Histologically, the HGCC consists of sheets of osteoclast-like giant cells with a background of mononuclear cells. The giant cells lack the pleomorphism seen in hepatocellular carcinomas with anaplastic giant cells. At the light microscopic level, most of this tumor was nearly identical to a GCT of bone, but several microscopic fields (less than 5% of the tumor) had the histologic appearance of a "usual" hepatocellular carcinoma. The hepatic tumor was negative for HAM 56, epithelial cytokeratins, muramidase, and alpha-1-antitrypsin, with only focal positivity for chymotrypsin in mononuclear and giant cells. The GCT was strongly positive for alpha-1-antitrypsin and chymotrypsin in both the mononuclear and giant cells and showed focal, weak staining for AE1 and AE3 in the mononuclear stromal cells. Ultrastructurally, both mononuclear and giant cells of the HGCC showed features typical of hepatocellular carcinoma. Although the patient presented in this report died, the pattern of growth was different from most hepatocellular carcinomas. The overall histologic features of this tumor are distinctive and appear to justify separating this variant from other types of hepatocellular carcinoma.     

Expression of hypoxia-inducible factors in human endometrium and suppression of matrix metalloproteinases under hypoxic conditions do not support a major role for hypoxia in regulating tissue breakdown at menstruation

BACKGROUND: Classical studies in monkeys suggested that menstruation results from vasoconstriction, hypoxia and necrosis. The heterodimeric hypoxia-inducible factor (HIF) complex is critical in oxygen homeostasis via increased stability of HIF-1alpha/2alpha monomers, and these act as markers of hypoxia. We hypothesized that focal hypoxia in perimenstrual endometrium results in locally increased matrix metalloproteinases (MMP), leading to tissue destruction. METHODS: HIF-1alpha, HIF-2alpha and HIF-1beta were immunolocalized in cycling endometrium. Endometrial stromal cells were cultured under hypoxic and normoxic conditions and MMP measured by zymography and Western blots. RESULTS: HIF-1alpha and HIF-2alpha were detected in only some endometrial samples, and not confined to the perimenstrual tissue. Where present, they were primarily cytoplasmic, not nuclear. HIF-1beta was localized in epithelium, leukocytes and some decidual cells. Cultured endometrial stromal cells responded to hypoxia with increased cellular HIF-1alpha and secreted vascular endothelial growth factor. ProMMP-1 and proMMP-3 production was reduced in response to hypoxia regardless of the steroidal milieu (no added steroids, estrogen or estrogen plus progesterone). Active MMP-2 and membrane type 1 MMP but not proMMP-2 or proMMP-9 production were also inhibited by hypoxia. CONCLUSIONS: These results do not support a role for hypoxia in the focally increased production and activation of MMP observed prior to and during menstruation.     

Similarities between giant cell tumor of bone, giant cell tumor of tendon sheath, and pigmented villonodular synovitis concerning ultrastructural cytochemical features of multinucleated giant cells and mononuclear stromal cells

The authors investigated ultrastructural cytochemical features of multinucleated and mononuclear stromal cells in giant cell tumor of bone (GCTB), giant cell tumor of tendon sheath (GCTTS), and pigmented villonodular synovitis (PVNS). Specimens of each tumor, respectively numbering 4, 4, and 3, were stained for tartrate-resistant acid phosphatase (TRAP) reactions and examined with an electron microscope. In GCTB and GCTTS, multinucleated cells, including some relatively small giant cells, showed TRAP activity and cytoplasmic features characteristic of osteoclasts, and also sometimes abundant rough endoplasmic reticulum and siderosomes. A few giant cells with macrophage-like features and slight TRAP activity were demonstrated in GCCTS and PVNS. In each tumor type, mononuclear cells showing TRAP activity shared cytoplasmic features with osteoclast-like multinucleated giant cells, while some others had macrophage-like features, and still others were poorly differentiated; a few mononuclear cells showed cell-to-cell contact. Ultrastructural similarities of TRAP-positive mononuclear cells in the three tumor types, and those between TRAP-positive multinucleated cells in GCTB and GCTTS, suggest a common cell lineage capable of multinucleated giant cell formation in the 3 tumors, despite differing histogenesis.     

Comparison of cytologic features of giant-cell tumor and giant-cell tumor of tendon sheath

The cytologic features in twelve cases of giant-cell tumor (GCT) and five cases of giant-cell tumor of tendon sheath (GCTTS) diagnosed by fine-needle aspiration cytology (FNAC) are described. All of these cases were histopathologically confirmed. The aspirates of GCT are composed of a dual population of mononucleated spindle cell and multinucleated giant cells. The peripheral adherence of giant cells to the spindle cell is the feature of diagnostic significance in GCT. In GCTTS, the aspirate consists of a polymorphic population composed of mononuclear histiocyte-like cells, hemosiderin laden macrophages, foamy macrophages, and a few multinucleated giant cells. FNAC can be used as a diagnostic tool for an early and accurate detection of these two giant cell-rich lesions, since the cytologic features when evaluated in conjunction with the clinical and radiologic features are sufficiently diagnostic.     

Detection of mRNAs for urokinase-type plasminogen activator, its receptor, and type 1 inhibitor in giant cell tumors of bone with in situ hybridization.

Although giant cell tumor of bone (GCT) is generally considered to be an uncommon benign neoplasm, it can pursue an aggressive course with local recurrence and metastasis. Attempts to predict the biological behavior of GCT with histopathological parameters, however, have not been successful. The urokinase-type plasminogen activation system has been implicated in tumor invasion and metastasis and abnormalities of the components of this system have been found in several malignancies. In this study we postulated that the urokinase-type plasminogen activation system associated with bone destruction and local invasion is present in GCT. We therefore evaluated the mRNA levels for urokinase-type plasminogen activator (u-PA), urokinase-type plasminogen activator receptor (u-PAR), and plasminogen activator inhibitor type 1 (PAI-1) by using Northern blot analysis and in situ hybridization in four cases of GCT and spindle-shaped mononuclear cells at the 35th passage from a GCT. Our results showed that giant cell tumors of bone contained variable levels of u-PA, u-PAR, and PAI-1 mRNA, respectively, 2.3, 1.4, and 3.2 kb in size. In situ hybridization showed that u-PA, u-PAR, and PAI-1 mRNA were expressed in both the mononuclear cells and the osteoclast-like giant cells; the signal for u-PA mRNA in the spindle-shaped mononuclear cells was more intense than that in the osteoclast-like multinuclear giant cells. Some spherical mononuclear cells (macrophage-like cells) expressed high levels of PAI-1 mRNA in comparison with the spindle-shaped mononuclear cells. In addition, the 35th passaged spindle-shaped mononuclear cells were used to study the gene expression of u-PA during cell proliferation. The results showed that the level of u-PA mRNA increases after adding 10% fetal calf serum to quiescent cells. The induction was maximal at 16 hours and remained high during 48 hours of treatment. In conclusion, even though osteoclast-like cells are ultimately responsible for the bone resorption of GCT, the mononuclear neoplastic cells of GCT may also be involved in degradation of the extracellular matrix during invasive growth by facilitating the urokinase plasminogen activation system. In addition, our observation of upregulation of u-PA mRNA in spindle-shaped mononuclear cells after serum stimulation indicated that u-PA production may be linked to tumor growth.     

Induction of membrane-type matrix metalloproteinase 1 (MT1-MMP) expression in human fibroblasts by breast adenocarcinoma cells

Membrane-type matrix metalloproteinase 1 (MT1-MMP) has been recently described as an activator of proMMP-2 (MMP-2) which is involved in tumor invasion. We have shown by in situ hybridization that MT1-MMP is produced by stromal cells in close contact to preinvasive and invasive tumor cells of breast carcinomas. Of particular interest was the observation that some fibroblasts express this enzyme in focal areas in preinvasive lesions, suggesting that particular tumor cells may stimulate fibroblasts to produce MT1-MMP. We have therefore compared the ability of two different breast cancer cell lines, one non-invasive (MCF7) and one invasive (MDA-MB-231) to stimulate MT1-MMP production in human fibroblasts with consequent proMMP-2-activation. The MDA-MB-231 conditioned medium induced MT1-MMP mRNAs in human fibroblasts and a parallel activation of proMMP-2 whereas MCF7 conditioned medium did not have any effect. These results suggest the existence of soluble factor(s) secreted by invasive or some preinvasive breast tumor cells which stimulate fibroblasts to produce and activate MMPs, and emphasize the cooperation between cancer and stromal cells in tumor invasion.     

Telomeric fusion is a major cytogenetic aberration of giant cell tumors of bone

Giant cell tumor of bone (GCT) is regarded as a rare primary bone neoplasm derived from stromal cells, which have the ability to recruit and harbor macrophage and multinucleated osteoclast-like giant cells. Despite being often considered benign, GCT is a problematic neoplasm in that it is aggressive, unpredictable and difficult to treat effectively. Cytogenetically GCT is characterised by a high frequency of telomeric fusion, a process which has been implicated in the production of chromosome instability and tumorigenesis. To extend our knowledge of the significance of telomere association in GCT, the cytogenetics of cell lines derived from spindle-shaped stromal-like mononuclear cells (the tumor cells) of GCT was investigated. Cell lines from three different patients showed telomeric association in all passages. The rate of telomeric association varied from line to line and from passage to passage, but there was no particular pattern to the variations. Many other cytogenetic abnormalities were seen as well as telomeric association, but these were rarely clonal. The nature of most of the other abnormalities seen, such as deleted chromosomes and chromosomes with additional unidentifiable material, was consistent with their being formed as a result of breakage of the dicentric fused chromosomes at a telophase. Chromosomes 13, 14 and 21 were most commonly involved in telomeric fusion. It appears that telomeric association persists in long-term cultures of GCT and is responsible for the accumulation of other associated cytogenetic aberrations. Telomeric reduction and telomerase activity may act as oncogenic events, promoting and sustaining the transformed GCT phenotype.     

Giant cell tumor of bone: An immunohistochemical comparative study

Forty-seven cases of giant cell tumor (GCT) of bone were reviewed pathologically to elucidate the origin of spindle-shaped stromal cells or the hlstogenesls of mononuclear histiocytic stromal cells and osteoclast-like giant cells (OCGC). To clarify the histogenesis of OCGC, eight cases of sarcoma associated with OCGC were reviewed for a comparative study. Spindle-shaped stromal cells sometimes produced minute foci of osteoid matrix. Proliferating cell nuclear antigen (PCNA) was observed In spindle-shaped stromal cells and mononuclear histlocytic stromal cells, but not in OCGC. Matrix metalloprotelnase (MMP)-9 was expressed by mononuclear histiocytic stromal cells and OCGC, and its expression was correlated with the lung metastasis rate. In both GCT and sarcomas with OCGC, mononuclear histiocytic stromal cells and OCGC expressed CD68, parathyroid hormone-like protein (PTH-LP), MMP-1 and MMP-9. Immunoreactivity of mononuclear histiocytic stromal cells and OCGC to CD68, PTH-LP, MMP-1 and MMP-9 was similar between GCT and sarcomas with OCGC. These observations may suggest that mononuclear histiocytic stromal cells and OCGC are reactively Induced with several cytokines acting in an autocrine or paracrine fashion and that these cells are closely related with the biologic aggressiveness of GCT.     

10例骨巨细胞瘤光镜和电镜观察

本文对10例骨巨细胞瘤(GCT)进行了光镜和电镜观察,同时10例冷包埋石蜡切片用偶联法进行酸性磷酸酶(ACP)组织化学观察。LM和EM均显示GCT、由单个核细胞(MC)和多核巨细胞(MGC)组成。MC包括成纤维细胞(FB)、组织细胞(HC)、原始间叶细胞、中间型细胞、黄色瘤细胞。其中4例有肌纤维母细胞(MFB),3例少数细胞内有N-内分泌颗粒。并且见到原始间叶细胞过渡为不同分化的FB和HC。MGC由MC融合而成,以HC型为主,少数兼有HC和FB的特征。ACP染色证实MGC多为HC型,亦证实MC中有HC,HC随级别的增高而逐渐减少,而FB随之逐渐增多。我们认为GCT起源于原始间叶细胞,HC、FB和MFB为肿瘤性细胞,MGC为反应性细胞。     

Giant cell tumor of the skin: a morphologic and immunohistochemical study of five cases

Giant cell tumor (GCT) of the skin is a rare entity that possesses similar gross and histologic features to GCT of bone. When located predominantly in the dermis GCT has been mistaken for benign fibrous histiocytoma and atypical fibroxanthoma. We report the clinical, morphologic, and immunohistochemical features of five cases of GCT of the skin. With one exception, all tumors are confined to the dermis. Patients' ages range from 6 to 78 years (median, 73 years) with a male to female ratio of 3:2. Gross and histologic features of the lesions are similar to those of GCT of bone (eg, brown fleshy tumor and a biphasic population of mononuclear cells admixed with osteoclast-like giant cells, respectively). The nuclei of the giant cells are similar to those of the mononuclear cells. A fascicular pattern with focal storiform arrangement of spindle neoplastic cells is noted in two cases. The osteoclast-like giant cells and some of the mononuclear cells are strongly positive for CD68, alpha-1-antitrypsin, and alpha-1-antichymotrypsin. Only the mononuclear cells express smooth muscle actin focally in one case. Both the osteoclast-like giant cells and the mononuclear cells are negative for cytokeratins (AE1/AE3 and CAM5.2) and S-100 protein in all cases. One patient developed lung metastases at presentation and local recurrence 4 months status post surgery. All patients are without evidence of disease 1 month to 12 years status post surgery. Cutaneous GCTs are low-grade sarcomas that can recur locally and infrequently metastasize. These tumors should be distinguished from a variety of cutaneous neoplasms that contain multinucleated giant cells.     

尿激酶型纤溶酶原激活物系统对骨巨细胞瘤细胞基质金属蛋白酶-2和组织基质金属蛋白酶抑制物-3表达的影响

目的:研究尿激酶型纤溶酶原激活物(uPA)及其受体(uPAR)信号转导对骨巨细胞瘤基质金属蛋白酶-2(MMP-2)和金属蛋白酶组织抑制物-3(TIMP-3)的调节。方法:用免疫组化检测骨巨细胞瘤组织中uPAR、MMP-2和TIMP-3的表达。用免疫共沉淀法检测uPA对瘤细胞信号转导通路的p44蛋白磷酸化水平。用蛋白印迹法检测用uPA和uPAR抗体处理后瘤细胞MMP-2和TIMP-3蛋白表达。结果:(1)uPAR主要表达在部分单核基质细胞和一些多核巨细胞的胞膜上;(2)MMP-2主要表达在瘤细胞的胞浆,在多核巨细胞,其表达有明显的极向性;(3)在骨巨细胞瘤组织TIMP-3表达量低于MMP-2,在多核巨细胞也显示极向性表达;(4)将uPA-ATF加入培养的骨巨细胞瘤细胞后,细胞信号通路上的p44蛋白磷酸化水平明显增高。用uPAR抗体处理后,细胞p44蛋白磷酸化水平明显降低。说明uPA-ATF参与细胞信号转导,而且受uPAR拮抗剂的影响;(5)uPA-ATF信号通路上调MMP-2和TIMP-3的表达,而uPAR抗体则下调MMP-2和TIMP-3的表达。结论:本实验首次直接证明uPA-ATF通过信号转导能调节MMP-2和TIMP-3的表达,而后者则在骨巨细胞瘤局部骨质吸收中起重要作用。     

Giant cell tumor of bone: Frequent actin immunoreactivity in stromal tumor cells

Although giant cell tumor (GCT) of bone is a well-recognized neoplasm with distinctive clinical and histopathological features, the origin of tumor cells, particularly of mononuclear cells, has not yet been established. An immunohistochemicai study was carried out on 11 cases of GCT of bone to examine the cellular natures of stromal mononuclear cells. In all cases, stromal cells were positive for muscle actin (HHF35) or α-smooth muscle actin, and in eight of 11 cases, positivist was intense and extensive. The cell margin of osteoclast-like giant cells (OGC) was stained positively by muscle actin, In addition to Intense and diffuse positive staining of the cytoplasm for KP1 (CD68), whereas α-smooth muscle acting exhibited a negative reaction on the OGC. In conclusion, the tumor cells with muscle actin and α-smooth muscle actin proclivities are not rare but frequently numerous In the GCT of bone; whereas further observation Is necessary to elucidate whether the stromal cells exhibit myoflbroblastlc cell differentiation exactly.     

Expression of interleukin (IL)-11 receptor by the human endometrium in vivo and effects of IL-11, IL-6 and LIF on the production of MMP and cytokines by human endometrial cells in vitro

Interleukin (IL)-6, leukaemia inhibitory factor (LIF) and IL-11 belong to the same family of cytokines whose receptors utilize gp130 as the signalling molecule. We have investigated the expression of the IL-11 receptor, IL-11Ralpha, protein in the human endometrium in vivo and the effects of IL-6, LIF and IL-11 on the production of metalloproteinases (MMPs) and cytokines by cultured endometrial epithelial and stromal cells. Immunostaining showed that IL-11Ralpha was expressed in both epithelial and stromal cells, with epithelial staining being more intense than stromal staining and little variation in staining in either compartment throughout the cycle. Incubation of both stromal and epithelial cells with IL-6, LIF and IL-11 had no effect on MMP-2, -7, -9, transforming growth factor (TGF)beta or IL-1beta production or cell growth. IL-6 and LIF also had no effect on tumour necrosis factor (TNF)alpha production, but IL-11 caused a dose-dependent decrease in TNFalpha production by epithelial cells. IL-6 receptor, LIF receptor and gp130 were all expressed by cultured stromal and epithelial cells, showing that the lack of effect is not due to lack of expression of the receptor components. The results show that although IL-6, LIF and IL-11 signal through the same molecule, they may have different effects in endometrial cells, suggesting the activation of different signalling pathways, which may ultimately be important in the control of endometrial function.