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- Carlinfante, G, et al.
(författare)
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Differential expression of osteopontin and bone sialoprotein in bone metastasis of breast and prostate carcinoma
- 2003
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Ingår i: Clinical and Experimental Metastasis. - 1573-7276 .- 0262-0898. ; 20:5, s. 437-444
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Tidskriftsartikel (refereegranskat)abstract
- Breast and prostate cancer often metastasise to the skeleton. Interestingly, the histopathological characteristics of the bone lesions that arise from these two cancer types differ. Breast tumours give rise to metastases in the skeleton with a mixed lytic/sclerotic pattern, whereas a predominantly sclerotic pattern is seen in metastases from prostate tumours. Osteopontin (OPN) and bone sialoprotein (BSP) are bone matrix proteins that have been implicated in the selective affinity of cancer cells for bone. In the present study, 21 patient cases with skeletal metastasis and their respective primary tumours ( 12 with breast cancer, 9 with prostate cancer) were investigated by immunohistochemistry in order to assess the level of OPN and BSP. Moderate to strong OPN expression was found in 42% of all breast tumours and in 56% of all prostate tumours. Significantly more breast cancer bone metastases exhibited high OPN expression, 83%, as compared with prostate tumour bone metastases, 11% ( P = 0.0019). In contrast, moderate to strong BSP expression was found in 33% of breast tumours and in 89% of prostate tumours. In the bone lesions, only 33% of breast tumour metastases showed moderate/strong BSP expression compared to 100% of prostate tumour metastases ( P = 0.0046). This divergent pattern of OPN/BSP expression could be an important determinant for the different characteristics of these two types of bone metastasis, i.e., lytic vs. sclerotic, consistent with the proposed role of OPN in differentiation and activation of osteoclasts and of BSP as a stimulator of bone mineralisation.
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- Carrino, David A, et al.
(författare)
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Age-related changes in the proteoglycans of human skin - Specific cleavage of decorin to yield a major catabolic fragment in adult skin
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:19, s. 17566-17572
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Tidskriftsartikel (refereegranskat)abstract
- Dramatic changes occur in skin as a function of age, including changes in morphology, physiology, and mechanical properties. Changes in extracellular matrix molecules also occur, and these changes likely contribute to the overall age-related changes in the physical properties of skin. The major proteoglycans detected in extracts of human skin are decorin and versican. In addition, adult human skin contains a truncated form of decorin, whereas fetal skin contains virtually undetectable levels of this truncated decorin. Analysis of this molecule, herein referred to as decorunt, indicates that it is a catabolic fragment of decorin rather than a splice variant. With antibody probes to the core protein, decorunt is found to lack the carboxyl-terminal portion of decorin. Further analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry shows that the carboxyl terminus of decorunt is at Phe(170) of decorin. This result indicates that decorunt represents the amino-terminal 43% of the mature decorin molecule. Such a structure is inconsistent with alternative splicing of decorin and suggests that decorunt is a catabolic fragment of decorin. A neoepitope antiserum, anti-VRKVTF, was generated against the carboxyl terminus of decorunt. This antiserum does not recognize intact decorin in any skin proteoglycan sample tested on immunoblots but recognizes every sample of decorunt tested. The results with anti-VRKVTF confirm the identification of the carboxyl terminus of decorunt. Analysis of collagen binding by surface plasmon resonance indicates that the affinity of decorunt for type I collagen is 100-fold less than that of decorin. This observation correlates with the structural analysis of decorunt, in that it lacks regions of decorin previously shown to be important for interaction with type I collagen. The detection of a catabolic fragment of decorin suggests the existence of a specific catabolic pathway for this proteoglycan. Because of the capacity of decorin to influence collagen fibrillogenesis, catabolism of decorin may have important functional implications with respect to the dermal collagen network.
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- Thur, Jochen, et al.
(författare)
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Mutations in cartilage oligomeric matrix protein causing pseudoachondroplasia and multiple epiphyseal dysplasia affect binding of calcium and collagen I, II, and IX
- 2001
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:9, s. 6083-6092
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in type 3 repeats of cartilage oligomeric matrix protein (COMP) cause two skeletal dysplasias, pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED). We expressed recombinant wild-type COMP that showed structural and functional properties identical to COMP isolated from cartilage. A fragment encompassing the eight type 3 repeats binds 14 calcium ions with moderate affinity and high cooperativity and presumably forms one large disulfide-bonded folding unit. A recombinant PSACH mutant COMP in which Asp-469 was deleted (D469 Delta) and a MED mutant COMP in which Asp-361 was substituted by Tyr (D361Y) were both secreted into the cell culture medium of human cells. Circular dichroism spectroscopy revealed only small changes in the secondary structures of D469 Delta and D361Y, demonstrating that the mutations do not dramatically affect the folding and stability of COMP. However, the local conformations of the type 3 repeats were disturbed, and the number of bound calcium ions was reduced to 10 and 8, respectively. In addition to collagen I and II, collagen IX also binds to COMP with high affinity. The PSACH and MED mutations reduce the binding to collagens I, II, and IX and result in an altered zinc dependence. These interactions may contribute to the development of the patient phenotypes and may explain why MED can also be caused by mutations in collagen IX genes.
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