Prognostic significance of abnormal matrix collagen remodeling in colorectal cancer based on histologic and bioinformatics analysis.

As the major component of the tumor matrix, collagen greatly influences tumor invasion and prognosis. The present study compared the remodeling of collagen and collagenase in 56 patients with colorectal cancer (CRC) using Sirius red stain and immunohistochemistry, exploring the relationship between collagen remodeling and the prognosis of CRC. Weak or strong changes in collagen fiber arrangement in birefringence were observed. With the exception of a higher density, weak changes equated to a similar arrangement in normal collagen, while strong changes facilitated cross­linking into bundles. Compared with normal tissues, collagen I (COL I) and III (COL III) deposition was significantly increased in CRC tissues, and was positively correlated with the metastasis status. In tissues without distant metastasis, collagen IV (COL IV) levels were higher than that in normal tissues, while in tissues with distant metastasis, collagen IV expression was significantly lower. Furthermore, the expression of matrix metalloproteinase (MMP)­1, MMP­2, MMP­7, MMP­9 and lysyl oxidase­like 2 (LOXL2) was found to be elevated in the cancer stroma, which contributed to the hyperactive remodeling of collagen. The association between collagen­related genes and the occurrence and prognosis of CRC were analyzed using biometric databases. The results indicated that patients with upregulated expression of a combination of coding genes for collagen and collagenase exhibited poorer overall survival times. The coding genes COL1A1­2, COL3A1, COL4A3, COL4A6 and MMP2 may therefore be used as biomarkers to predict the prognosis of patients with CRC. Furthermore, the results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggest that collagen may promote tumor development by activating platelets. Collectively, the abnormal collagen remodeling, including associated protein and coding genes is associated with the tumorigenesis and metastasis, affecting the prognosis of patients with CRC.

Spatio-temporal expression and distribution of collagen VI during zebrafish development.

Collagen VI (ColVI) is an extracellular matrix (ECM) protein involved in a range of physiological and pathological conditions. Zebrafish (Danio rerio) is a powerful model organism for studying vertebrate development and for in vivo analysis of tissue patterning. Here, we performed a thorough characterization of ColVI gene and protein expression in zebrafish during development and adult life. Bioinformatics analyses confirmed that zebrafish genome contains single genes encoding for α1(VI), α2(VI) and α3(VI) ColVI chains and duplicated genes encoding for α4(VI) chains. At 1 day post-fertilization (dpf) ColVI transcripts are expressed in myotomes, pectoral fin buds and developing epidermis, while from 2 dpf abundant transcript levels are present in myosepta, pectoral fins, axial vasculature, gut and craniofacial cartilage elements. Using newly generated polyclonal antibodies against zebrafish α1(VI) protein, we found that ColVI deposition in adult fish delineates distinct domains in the ECM of several organs, including cartilage, eye, skin, spleen and skeletal muscle. Altogether, these data provide the first detailed characterization of ColVI expression and ECM deposition in zebrafish, thus paving the way for further functional studies in this species.

Methods in studying ECM degradation.

Almost all tissues in our body contain specific cells associated with the tissue itself, and an extracellular matrix (ECM) that consists of a variety of proteins of which the bulk is formed by different types of collagens, glycoproteins and proteoglycans. The ECM plays a pivotal role in numerous processes not only related to the mechanical properties of a tissue, but also in modulating cellular activity. For a proper functioning of a tissue remodeling of the ECM is essential. Some connective tissues are characterized by a very rapid turnover (e.g. periodontal ligament) whereas others hardly show signs of turnover (e.g. cartilage). In all situations degradation of the ECM constituents occur. Under certain conditions, especially during a pathological situation, a high level of degradation may take place. In other situations matrix synthesis and deposition outstrips breakdown, leading to a fibrosis. In order to obtain information on the level of degradation of the different ECM components, various methods have been employed. A number of these methods will be discussed in this article.

Studies of novel hyaluronic acid-collagen sponge materials composed of two different species of type I collagen.

The authors have developed novel hyaluronic acid (HA)-collagen sponge materials (HACSMs) composed of various ratios of bird feet (BF) and pig skin (PS) collagen that are fabricated employing a combination of freezing, lyophilizing, and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) crosslinking methods. Morphology, swelling ratio, resistance to collagenase, thermal stability, tensile strength, and free amine index are determined to evaluate the physical-chemical properties of various HACSMs. Different BF: PS ratios directly vary with the physical-chemical properties of HACSMs and control their biodegradability for multiple uses. Resistance to collagenase, thermal stability, and tensile strength of HACSMs increases as the ratio of BF collagen increases. On the contrary, the higher swelling ratio, free amine index, and pore size occur in materials composed of higher ratios of PS collagen. A linear relationship between the decreased ratio of PS collagen and the increase in tensile strength and biostability are observed. The materials of B4P1HA (BF: PS: HA=4: 1: 0.2) exhibit the highest value of tensile strength, but no significant difference exists between B4P1HA and B5P0HA (BF: PS: HA=5: 0: 0.2). These phenomena should be closely related to the BF collagen which contains a higher amount of carboxyl groups of glutamic or aspartic acid residues and forms more amine bonds under EDC cross-linking when compared to PS collagen. However, these results suggest that the B4P1HA and B5P0HA materials should be produced according to highest bio-stability and mechanical strength and, furthermore they may be suitable for artificial skin or drug delivery applications.