Mirva Söderström

Expression of Cathepsins B, H, K, L, and S and Matrix Metalloproteinases 9 and 13 During Chondrocyte Hypertrophy and Endochondral Ossification in Mouse Fracture Callus

Abstract. Fracture repair provides an interesting model for chondrogenesis and osteogenesis as it recapitulates in an adult organism the same steps encountered during embryonic skeletal development and growth. The fracture callus is not only a site of rapid production of cartilage and bone, but also a site of extensive degradation of their extracellular matrices. The present study was initiated to increase our understanding of the roles of different proteolytic enzymes, cysteine cathepsins B, H, K, L, and S, and matrix metalloproteinases (MMPs) 9 and 13, during fracture repair, as this aspect of bone repair has previously received little attention. Northern analysis revealed marked upregulation of cathepsin K, MMP-9, and MMP-13 mRNAs during the first and second weeks of healing. The expression profiles of these mRNAs were similar with that of osteoclastic marker enzyme tartrate-resistant alkaline phosphatate (TRAP). The changes in the mRNA levels of cathepsins B, H, L, and S were smaller when compared with those of the other enzymes studied. Immunohistochemistry and in situ hybridization confirmed the predominant localization of cathepsin K and MMP-9 and their mRNA in osteoclasts and chondroclasts at the osteochondral junction. MMP-13 was present in osteoblasts and individual hypertrophic chondrocytes near the cartilage-bone interphase. In cartilaginous callus, the expression of cathepsins B, H, L, and S was mainly related to chondrocyte hypertrophy. During bone remodeling both osteoblasts and osteoclasts contained these cathepsins. The present data demonstrate that degradation and remodeling of extracellular matrices during fracture healing involves activation of MMP-13 production in hypertrophic chondrocytes and osteoblasts, and cathepsin K and MMP-9 production in osteoclasts and chondroclasts.

Cathepsin expression during skeletal development.

Cysteine proteinases, cathepsins B, H, K, L and S, have been implicated in several proteolytic processes during development, growth, remodeling and aging, as well as in a variety of pathological processes. For systematic analysis of cathepsin gene expression we have produced cDNA clones for mouse and human cysteine cathepsins. Northern analysis of a panel of total RNAs isolated from 16-19 different human and mouse tissues revealed the presence of mRNAs for cathepsin B, H, K, L and S in most tissues, but each with a distinct profile. Of the different cathepsin mRNAs, those for cathepsin K were clearly the highest in bone and cartilage. However, relatively high mRNA levels for the other cathepsins were also present in these tissues. To better understand the roles of different cathepsins during endochondral ossification in mouse long bones, cathepsin mRNAs were localized by in situ hybridization. Cathepsin K mRNAs were predominantly seen in multinucleated chondroclastic and osteoclastic cells at the osteochondral junction and on the surface of bone spicules. The other cathepsin mRNAs were also seen in osteoclasts, and in hypertrophic and proliferating chondrocytes. These observations were confirmed by immunohistochemistry and suggest that all cysteine cathepsins are involved in matrix degradation during endochondral ossification.

MMP-1 expression has an independent prognostic value in breast cancer

AbstractBackgroundBreast cancer consists of a variety of tumours, which differ by their morphological features, molecular characteristics and outcome. Well-known prognostic factors, e.g. tumour grade and size, Ki-67, hormone receptor status, HER2 expression, lymph node status and patient age have been traditionally related to prognosis. Although the conventional prognostic markers are reliable in general, better markers to predict the outcome of an individual tumour are needed.Matrix metalloproteinase-1 (MMP-1) expression has been reported to inversely correlate with survival in advanced cancers. In breast cancer MMP-1 is often upregulated, especially in basal-type breast tumours. The purpose of this retrospective study was to analyse MMP-1 expression in breast cancer cells and in cancer associated stromal cells and to correlate the results with traditional prognostic factors including p53 and bcl-2, as well as to patient survival in breast cancer subtypes.MethodsImmunohistochemical analysis of MMP-1, ER, PR, Ki-67, HER2, bcl-2, p53 and CK5/6 expression was performed on 125 breast cancers. Statistical analyses were carried out using Kruskal-Wallis and Mann-Whitney -tests. In pairwise comparison Bonferroni-adjustment was applied. Correlations were calculated using Spearman rank-order correlation coefficients. Kaplan-Meier survival analyses were carried out to compare breast cancer-specific survival curves. Factors significantly associated with disease-specific survival in univariate models were included in multivariate stepwise.ResultsPositive correlations were found between tumour grade and MMP-1 expression in tumour cells and in stromal cells. P53 positivity significantly correlated with MMP-1 expression in tumour cells, whereas HER2 expression correlated with MMP-1 both in tumour cells and stromal cells. MMP-1 expression in stromal cells showed a significant association with luminal A and luminal B, HER2 overexpressing and triple-negative breast cancer subtypes.ConclusionsThe most important finding of this study was the independent prognostic value of MMP-1 as well as Ki-67 and bcl-2 expression in tumour cells. Our study showed also that both tumoural and stromal MMP-1 expression is associated with breast tumour progression and poor prognosis. A significant difference of MMP-1 expression by cancer associated stromal cells in luminal A, luminal B and triple-negative breast cancer classes was also demonstrated. Please see related commentary articlehttp://www.biomedcentral.com/1741-7015/9/95

Molecular profiling of human chondrosarcomas for matrix production and cancer markers

Chondrosarcoma is the second most common malignant bone tumor, characterized by production of abundant extracellular matrix resembling hyaline cartilage. To better understand the molecular pathogenesis of chondrosarcoma, we analyzed 12 chondrosarcomas for their production of connective tissue components and SOX9, a key regulator of normal chondrocyte differentiation. Furthermore, 10 chondrosarcoma samples were screened for additional changes in gene expression using cDNA array analysis. In Northern analysis, several tumors were found to express type II collagen mRNA at levels comparable to fetal cartilage used as a control. Interestingly, the highest levels of type II collagen mRNA were seen in 2 of the 3 grade 3 chondrosarcomas, which also exhibited the highest mRNA levels of SOX9 and “prechondrogenic” proα1(IIA) collagen. Expression of SOX9 in human chondrosarcomas is novel and suggests that chondrosarcomas originate from a multipotent stem cell committed to differentiation along the chondrogenic pathway. Results of the cDNA array analyses emphasize the heterogenous nature of chondrosarcoma as no single transcript was systematically up‐ or downregulated in all tumors analyzed. Among the interesting changes observed was upregulation of decorin mRNA in 7 of the 10 tumors analyzed. Further studies are needed to determine whether decorin plays a role in the pathogenesis of chondrosarcoma. The cDNA arrays also revealed discrepancies from Northern and RNase protection analyses in transcript levels of matrix components, emphasizing the need to validate cDNA array data with other techniques.

Analysis of cyclins A, B1, D1 and E in breast cancer in relation to tumour grade and other prognostic factors

BackgroundThe cell cycle is promoted by activation of cyclin dependent kinases (Cdks), which are regulated positively by cyclins and negatively by Cdk inhibitors. Proliferation of carcinoma is associated with altered regulation of the cell cycle. Little is known on the combined alterations of cyclins A, B1, D1 and E in breast cancer in relation to the tumour grade and other prognostic factors.FindingsImmunohistochemical analysis of cyclins A, B1, D1 and E, estrogen receptor, progesterone receptor, Ki-67, Her-2/neu and CK5/6 was performed on 53 breast carcinomas. mRNA levels of the cyclins were analysed of 12 samples by RT-PCR. The expression of cyclins A, B1 and E correlated with each other, while cyclin D1 correlated with none of these cyclins. Cyclins A, B1 and E showed association with tumour grade, Her-2/neu and Ki-67. Cyclin E had a negative correlation with hormone receptors and a positive correlation with triple negative carcinomas. Cyclin D1 had a positive correlation with ER, PR and non-basal breast carcinomas.ConclusionCyclin A, B1 and E overexpression correlates to grade, Ki-67 and Her2/neu expression. Overexpression of cyclin D1 has a positive correlation with receptor status and non-basal carcinomas suggesting that cyclin D1 expression might be a marker of good prognosis. Combined analysis of cyclins indicates that cyclin A, B and E expression is similarly regulated, while other factors regulate cyclin D1 expression. The results suggest that the combined immunoreactivity of cyclins A, B1, D and E might be a useful prognostic factor in breast cancer.

No improvement in the overall survival of 194 patients with chondrosarcoma in Finland in 1971–1990

We describe the clinicopathologic profile and survival of 306 patients with chondrosarcoma reported to the Finnish Cancer Registry in 1971–1990. 218 cases were available for reevaluation. Owing to their various clinicopathologic characteristics, we excluded the histologic variants of chondrosarcoma. Therefore, the final study population included 194 patients. The minimum follow-up was 9 years. The study population included 69 grade 1 tumors, 114 grade 2 tumors, and 11 grade 3 tumors. The commonest tumor sites were the chest, pelvis and femur. A local recurrence developed in 25% of the patients and metastatic lesions in 18%. The patients were treated in 31 hospitals (in 22 hospitals during the 1970s and in 26 in the 1980s), and the number of patients biopsied before the referral remained about the same from the 1970s (15%) to the 1980s (18%). The 5-and 10-year disease-specific survival rates were 70% and 57%, respectively. Multivariate analysis showed that the most important independent predictors of shortened survival were high histologic grade, age 50 years or older, and a diagnosis in the 1980s, as compared to the 1970s. Most findings accorded with reports from specialist treatment centers, but to our surprise, the survival rate declined among patients diagnosed in the 1980s versus the 1970s. The failure to improve patient survival is probably due to treatment of the patients in 31 hospitals rather than in a few centers dealing with treatment of cancer.

Cdc20 and securin overexpression predict short-term breast cancer survival

Background:Cdc20 is an essential component of cell division and responsible for anaphase initiation regulated by securin degradation. Cdc20 function is strongly regulated by the spindle assembly checkpoint to ensure the timely separation of sister chromatids and integrity of the genome. We present the first results on Cdc20 in a large clinical breast cancer material.Methods:The study was based on 445 breast cancer patients with up to 20 years of follow-up (mean 10.0 years). DNA content was determined by image cytometry on cell imprints, and Cdc20 and securin immunohistochemistry on tissue microarrays of breast cancer tissue.Results:In our results, high Cdc20 and securin expression was associated with aneuploid DNA content. In prognostic analyses, high Cdc20 immunoexpression alone and in combination with high securin immunoexpression indicated aggressive course of disease and up to 6.8-fold (P<0.001) risk of breast cancer death. Particularly, high Cdc20 and securin immunoexpression identified a patient subgroup with extremely short, on average 2.4 years, breast cancer survival and triple-negative breast cancer (TNBC) subtype.Conclusions:We report for the first time the association of high Cdc20 and securin immunoexpression with extremely poor outcome of breast cancer patients. Our experience indicates that Cdc20 and securin are promising candidates for clinical applications in breast cancer prognostication, especially in the challenging prognostic decisions of TNBC.

Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human chondrosarcomasNote

The aim of the present study was to characterise the ability of malignant chondrosarcomas to invade normal bone by analysing their production of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). For this purpose 12 chondrosarcomas were investigated for the expression of mRNAs for several MMPs and all 4 TIMPs by Northern hybridisation, and for immunohistochemical localisation of the proteins. A characteristic finding of these analyses was increased expression of MMP‐13, MMP‐14 and TIMP‐2 mRNAs in chondrosarcomas when compared with nonmalignant control samples. Individual chondrosarcomas also exhibited elevated levels of MMP‐1, MMP‐7 and MMP‐9 mRNAs. The results of Northern hybridisations were supported by immunohistochemical stainings of the corresponding tumour areas for MMP‐2, MMP‐14 and TIMP‐2, further suggesting that these may have prognostic value for determining whether individual chondrosarcomas are locally aggressive or have a probability of recurrence. Another finding of the present study was a marked heterogeneity in histologic appearance and gene expression of the chondrosarcomas, emphasising the importance of analysing several areas of these tumours to get representative results. These findings suggest that analysis of MMPs could be a useful diagnostic indicator in patients with cartilaginous tumours and could help in differentiating between a low‐grade malignant chondrosarcoma and a benign growing enchondroma.

Differential Expression of Decorin by Human Malignant and Benign Vascular Tumors

An increasing amount of evidence indicates that a small extracellular chondroitin/dermatan sulfate proteoglycan, decorin, is indirectly involved in angiogenesis. Given that angiogenesis is a sine qua non for tumor growth and progression, we attempted to examine whether human malignant vascular tumors differ from human benign vascular tumors in terms of their decorin expression and synthesis. CD31 immunostaining demonstrated that the human malignant vascular tumors Kaposis sarcoma and angiosarcoma were filled with capillary-like structures, whereas in benign cavernous and capillary hemangiomas, blood vessels were not as abundantly present. By utilizing in situ hybridization and immunocytochemical assays for decorin, we showed that there was no detectable decorin mRNA expression or immunoreactivity within the tumor mass in the Kaposis sarcoma or angiosarcoma group. Instead, decorin was expressed in the connective tissue stroma lining the sarcoma tissue. In contrast to sarcomas, in hemangiomas, decorin mRNA expression and immunoreactivity were observed also within the tumor mass, particularly in the connective tissue stroma surrounding the clusters of intratumoral blood vessels. Finally, distribution of type I collagen was found to be similar to that of decorin in these tumor tissues. Our findings can be explained with different states of angiogenesis in dissimilar growths. In sarcomas, angiogenesis is extremely powerful, whereas in hemangiomas, angiogenesis has ceased. Thus, decorin is likely to possess a suppressive effect on human tumor angiogenesis in vivo, as previously described by studies using different experimental models. Decorin certainly provides a usable biomarker for distinguishing between benign and malignant vascular tumors in patients.

Localization of decorin gene expression in normal human breast tissue and in benign and malignant tumors of the human breast

The small extracellular matrix proteoglycan decorin which possesses a potent antitumor activity has been shown to be present in various amounts in the stroma of several tumors including those of the breast. Regarding decorin in breast malignancies the published data are conflicting, i.e., whether breast cancer cells express it or not. Here, we first compared decorin gene expression levels between healthy human breast tissue and selected types of human breast cancer using GeneSapiens databank. Next, we localized decorin mRNA in tissue specimen of normal human breast, intraductal breast papillomas and various histologic types of human breast cancer using in situ hybridization (ISH) with digoxigenin-labeled RNA probes for decorin. We also examined the effect of decorin transduction on the behavior of cultured human breast cancer MCF7 cells. Analysis of GeneSapiens databank revealed that in various human breast cancers decorin expression is significant. However, ISH results clearly demonstrated that human breast cancer cells independently of the type of the cancer do not express decorin mRNA. This was also true for papilloma-forming cells of the human breast. Indeed, decorin gene expression in healthy human breast tissue as well as in benign and malignant tumors of human breast was shown to take place solely in cells of the original stroma. Decorin transduction using decorin adenoviral vector in decorin-negative MCF7 cells resulted in a significant decrease in the proliferation of these cells and changed cell cohesion. Decorin-transduced MCF7 cells also exhibited increased apoptosis. In conclusion, our study shows that in human breast tissue only cells of the original stroma are capable of decorin gene expression. Our study also shows that transduction of decorin in decorin-negative human breast cancer cells markedly modulates the growth pattern of these cells.