These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Molecular events that contribute to lysyl oxidase enzyme activity and insoluble collagen accumulation in osteosarcoma cell clones.
    Author: Uzel MI, Shih SD, Gross H, Kessler E, Gerstenfeld LC, Trackman PC.
    Journal: J Bone Miner Res; 2000 Jun; 15(6):1189-97. PubMed ID: 10841188.
    Abstract:
    Maximum collagen synthesis and maximum accumulation of insoluble collagen occur at different phenotypic stages in developing osteoblastic cell cultures. Insoluble collagen accumulation depends in part on the activity of extracellular enzymes including procollagen N-proteinases, procollagen C-proteinase (derived from the BMP1 gene), and lysyl oxidase. In addition to its action on procollagen, procollagen C-proteinase processes prolysyl oxidase to mature 32-kDa lysyl oxidase. The regulation of extracellular activities that control insoluble collagen accumulation has not been studied extensively. The present study compares molecular events that control production of a collagenous mineralized extracellular matrix in vitro among five different murine osteosarcoma cell clones derived from the same tumor, but which differ in their ability to produce an insoluble mineralized matrix. Levels of insoluble type I collagen, insoluble calcium, bone morphogenetic protein 1 (BMP-1), and lysyl oxidase expression, lysyl oxidase biosynthesis, lysyl oxidase activity, and prolysyl oxidase processing activity were determined. Results surprisingly indicate that lysyl oxidase activity is not related closely to lysyl oxidase messenger RNA (mRNA) levels among the different cell clones. However, it appears that BMP-1-dependent prolysyl oxidase processing could contribute to the observed lysyl oxidase activity. Highest collagen and BMP-1 mRNA levels, prolysyl oxidase processing activity, and lysyl oxidase activity occurred in a cell clone (K8) that showed the highest levels of insoluble collagen accumulation. Culture media from a cell clone (K37) that accumulates little insoluble collagen or calcium but expresses high levels of lysyl oxidase mRNA contained low molecular weight fragments of lysyl oxidase protein and showed low lysyl oxidase activity. By contrast the K14 cell line exhibits relatively high lysyl oxidase activity and collagen accumulation, but low levels of mature lysyl oxidase protein. Together, these studies indicate that catabolic as well as anabolic activities are important in regulating insoluble collagen accumulation in osteoblastic cells. In addition, results suggest that products of genes homologous to lysyl oxidase may contribute to observed lysyl oxidase activity.
    [Abstract] [Full Text] [Related] [New Search]