Hyaluronate binding assay study of transfected CD44 V4-V7 isoforms into the human gastric carcinoma cell line SC-M1

Abstract

The potential human metastasis molecule CD44 and its isoforms V5 and V6 are overexpressed in human gastric carcinoma. Among the numerous extracellular matrix components, hyaluronate, a CD44 ligand, is of increasing interest in relation to its role in cancer cell development and invasion. By using the dynabead separation method, the SC‐M1 cell line was separated into V5 and V6 isoform‐positive and ‐negative populations. The V5 and V6 isoform‐negative populations exhibited significantly higher hyaluronate binding activity than the corresponding positive cells. The hyaluronate binding activity of V5 and V6‐positive cells could be restored by pretreatment with anti‐CD44 V5 and V6 monoclonal antibodies (MAbs). In addition, transfection of an expression vector containing CD44 V5 and V6 into V5 and V6‐negative cells decreased their hyaluronate binding activity to the levels of CD44 V5 and V6‐positive cells. Cells transfected with V5 and V6 recovered their hyaluronate binding activity after pretreatment with MAbs against V5 and V6. These data suggest that cell adhesion involving hyaluronate can be regulated by multiple mechanisms, one of which involves alternative splicing of CD44 isoforms. © 1998 John Wiley & Sons, Ltd.

Prostate cancer invasion is influenced more by expression of a CD44 isoform including variant 9 than by Muc18

“…46 However, gastric carcinoma cells negative for CD44v5 and v6 exhibited higher hyaluronate binding than the corresponding posi- tive cells. 47 CD44v9 also is involved in binding of myeloma cells to bone marrow stromal cells, but not to hyaluronate, and these effects were suggested to explain why CD44v9 expression worsens the prognosis in multiple myeloma. 48 On the other hand, melanoma cell lines that had increased relative CD44v10 expression showed significantly higher migration rates on immobilized hyaluronate.…”

Molecular studies into the role of CD44 variants in metastasis in gastric cancer

“…Because CD44 is known to be a hyaluronate receptor, Harn et al investigated whether there is a correlation between hyaluronate binding activity and CD44 V5 and V6 isoform expression. 42 By using the Dynabead separation method and one of the well established gastric adenocarcinoma cell lines, SC-M1 was separated into V5 and V6 isoform positive and negative populations. The V5 and V6 isoform negative populations exhibited significantly higher hyaluronate binding activity than the corresponding positive cells (fig 1).…”

“…These data suggest that cell adhesion involving hyaluronate can be regulated by multiple mechanisms, one of which involves alternative splicing of CD44 isoforms. 42 To date, most reports have described that the regulation of CD44 binding to hyaluronate is by glycosylation of variably spliced exons. [43][44][45] The results of Harn et al indicated that the V4−V7 isoforms themselves, in addition to the glycosylation, can alter the hyaluronate binding.…”