Year-end Sale % OFF 
Abstract
The products of ras and src proto-oncogenes are frequently activated in a constitutive state in human colorectal cancer. In this study we attempted to establish whether the tumorigenic progression induced by oncogenic activation of p21ras and pp60c-src in human colonic Caco-2 cells is associated with specific alterations of syndecan-1, a membrane-anchored proteoglycan playing a role in cell-matrix interaction and neoplastic growth control. To this end, we used Caco-2 cells made highly tumorigenic by transfection with an activated (Val 12) human Ha-ras gene or with the polyoma middle T (Py-MT) oncogene, a constitutive activator of pp60c-src tyrosine kinase activity. Compared with control vector-transfected Caco-2 cells, both oncogene-transfected cell lines (1) contained smaller amounts of membrane-anchored PGs; (2) exhibited decreased syndecan-1 expression at the protein but not the mRNA level; (3) synthesized 35S-labelled syndecan-1 with decreased specific activity; (4) produced a syndecan-1 ectodomain with a lower molecular mass and reduced GAG chain size and sulphation; and (5) expressed heparanase degradative activity. These results show that the dramatic activation of the tumorigenic potential induced by oncogenic p21ras or Py-MT/pp60c-src in Caco-2 cells is associated with marked alterations of syndecan-1 expression at the translational and post-translational levels.
Highlights
MethodsCarrier-free Na235SO4 (270 mCi mmol-') was purchased from New England Nuclear, Boston, MA, USA
Caco-2 cells is associated with marked alterations of syndecan-1 expression at the translational and posttranslational levels
In the oncogene-transfected Caco-2-MT cells (Figure lb) and Caco-2-T cells (Figure Ic), only 40.5% and 37.2% of the total 35S-labelled PGs bound to the column, and the hydrophobic PG fractions eluted at Triton X-100 concentrations of 0.11% and 0.09% respectively
Summary
Carrier-free Na235SO4 (270 mCi mmol-') was purchased from New England Nuclear, Boston, MA, USA. Chondroitin ABC lyase (EC 4.2.2.4) was obtained from Seikagaku Fine Chemicals, Tokyo, Japan. PD-10 columns, Sepharose CL-4B and Sepharose CL-6B were obtained from Pharmacia Fine Chemicals, Uppsala, Sweden. DEAE-Sephacel was from Whatman Biochemicals, Maidstone, Kent, UK. 3 - [3 - cholamido propyl) dimethyl - ammonio] - 1 - propane sulphonate (CHAPS), phenylmethylsulphonyl fluoride (PMSF), N-ethylmaleimide (NEM) and benzamidine were from Calbiochem, San Diego, USA. Soybean trypsin inhibitor was from Sigma Chemical Company, St Louis, Missouri. Zeta-probe membranes were from Bio-Rad Laboratories, Richmond, USA and Immobilon-N membranes from Millipore, Bedford, MA, USA. All other reagents, obtained from Boehringer Mannheim, Indianapolis, IN, USA, were of the highest analytical grade
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
