Purification and characterization of collagens from rat fibrosarcoma induced by 3-methylcholanthrene

Abstract

The distribution of various collagen types was studied in rat fibrosarcoma. Collagens extracted from fibrosarcoma tissue were characterized by the criteria of solubility in NaCl, SDS-PAGE, ion exchange chromatography, CNBr peptide mapping and amino acid analysis. Fibrosarcoma was found to produce excess amount of type V, type I trimer and type III collagens; comparatively, type I collagen and total collagen content were noticed to decrease in fibrosarcoma. We observe that the increase in type V collagen content in fibrosarcoma might be due to the enhanced transcription of type V collagen gene. Increased type I trimer collagen in fibrosarcoma might be attributed to the differential expression of alpha 1(I) and alpha 2(I) gene and might also be due to the expression of a different gene for type I trimer collagen.

Carcinomas Contain a Matrix Metalloproteinase–Resistant Isoform of Type I Collagen Exerting Selective Support to Invasion

“…We took a cue from an observation that homotrimers refolded in vitro from denatured α1(I) chains were resistant to MMP-1 and MMP-8 (24); although the refolding could result in improper chain register, disrupting the normal collagenase cleavage site. Testing of our hypothesis revealed that naturally produced homotrimers were indeed resistant to cleavage by all collagenolytic MMPs (1, 2, 8, 13, and 14) and to degradation by fibroblasts and cancer cells. In culture, the homotrimers comprised 15 to 40% of type I collagen secreted by invasive melanoma, adenocarcinoma, fibrosarcoma, and neuroblastoma cells, but they were not produced by normal fibroblasts.…”

“…A fetal, homotrimeric isoform (α1 3 ) with three α1(I) chains was found in carcinomas (10-14) and in cultures of chemically transformed (15, 16) and cancer (17-21) cells. It was suggested that the homotrimers may enhance proliferation (22) and migration (23) of cancer cells, but their role in cancer pathophysiology was not established.…”

The Interface between Catalytic and Hemopexin Domains in Matrix Metalloproteinase-1 Conceals a Collagen Binding Exosite

“…We are mindful that in nondiseased adult tissue, the majority of type I collagen exists as ␣1(I) 2 ␣2(I) heterotrimers (50). Indeed, ␣1(I) 3 homotrimers only exist in significant quantities in vivo in fetal tissues (51), carcinomas (50,(52)(53)(54)(55), fibrotic tissues (56 -58), and in genetic disorders in which the ␣2(I) chain is deficient (59 -61). Thus, the homotrimeric THP used in this study is not strictly representative of the homeostatic state.…”

Rat Fibrosarcoma as a Source of Stable Co-Polymer of Type I and Type III Collagens

“…The insoluble (in 0.05 M Tris-HCl + 1 M NaCl) complex was a consistent finding in all our analyses when we pepsinised the tissue directly [11,13]. Asokan et al [14] extracted with NaCl and acetic acid prior to pepsin and may have extracted the complexes in these extracts. The complexes may represent the crosslinked components observed at the top of their gel.…”

“…Asokan et al [ 14] have found that similarly induced rat fibrosarcomas produce excess amounts of type V, type I trimer and type III collagens, while type I and total colla gens were decreased, but they make no mention of an insoluble complex. The insoluble (in 0.05 M Tris-HCl + 1 M NaCl) complex was a consistent finding in all our analyses when we pepsinised the tissue directly [11,13].…”