The hyaluronan receptor RHAMM/IHABP in astrocytoma cells: expression of a tumor-specific variant and association with microtubules

J Neurooncol. 2002 Aug;59(1):15-26. doi: 10.1023/a:1016373015569.


Hyaluronan binding to its cellular receptors CD44 and ICAM-1 appears to enhance the malignant behavior of tumors, including astrocytomas. RHAMM/IHABP, another hyaluronan receptor, has been identified in breast carcinoma cells, but its presence in astrocytomas is yet undetermined. Herein, we report that a monoclonal antibody against plectin (a cytoskeletal protein linker) recognizes on Western blots of U-373 MG glioblastoma cells, a 300-kDa band corresponding to plectin and two bands of 86 and 70 kDa. cDNA cloning and Northern blotting reveals that these two bands represent isoforms of RHAMM/IHABP. Sequence comparisons suggest that the plectin monoclonal antibody recognizes RHAMM/IHABP because this protein and plectin share short peptide sequences of similar primary and secondary structure. Western blotting demonstrates that most human astrocytoma tissues and cell lines express the 86- and 70-kDa isoforms of RHAMM/IHABP. Interestingly, the 70-kDa variant is undetectable in normal brain tissues and in primary cultures of astrocytes suggesting that its expression is tumor-specific. Transfection experiments with epitope-tagged RHAMM/IHABP cDNA established that RHAMM/IHABP associates with microtubules in astrocytoma cells, while in normal astrocytes it either co-localizes with microtubules or has a diffuse cytoplasmic distribution. This suggests that RHAMM/IHABP has the capacity to bind to microtubules in normal and transformed astrocytes, and that neoplasia may favor this association.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence / genetics
  • Animals
  • Antibodies, Monoclonal
  • Astrocytoma / genetics*
  • Astrocytoma / metabolism*
  • Base Sequence / genetics
  • Blotting, Northern
  • Cells, Cultured
  • Cricetinae
  • Cytoplasm / metabolism
  • Extracellular Matrix Proteins / chemistry
  • Extracellular Matrix Proteins / genetics
  • Extracellular Matrix Proteins / metabolism*
  • Genetic Variation*
  • Humans
  • Hyaluronan Receptors / chemistry
  • Hyaluronan Receptors / genetics
  • Hyaluronan Receptors / metabolism*
  • Intermediate Filament Proteins / immunology
  • Microtubules / metabolism*
  • Molecular Sequence Data
  • Molecular Weight
  • Plectin
  • Protein Isoforms / metabolism
  • Reference Values
  • Transfection


  • Antibodies, Monoclonal
  • Extracellular Matrix Proteins
  • Hyaluronan Receptors
  • Intermediate Filament Proteins
  • PLEC protein, human
  • Plectin
  • Protein Isoforms
  • hyaluronan-mediated motility receptor