Cloning of an isoform of integrin-linked kinase (ILK) that is upregulated in HT-144 melanoma cells following TGF-β1 stimulation

Bassam Janji, Chantal Melchior, Laurent Vallar, Nelly Kieffer*

*Corresponding author for this work

    Research output: Contribution to journalArticleResearchpeer-review

    27 Citations (Scopus)


    We have shown previously that integrin-linked kinase (ILK) is upregulated in human HT-144 melanoma cells following TGF-β1 stimulation. Using mRNA from TGF-β1 stimulated HT-144 tells and reverse transcriptase polymerase chain reaction, we have isolated a cDNA encoding a protein highly homologous to ILK. Sequencing of the full-length 1359 base pair cDNA and polypeptide translation revealed that this protein, designated ILK-2, differs from the known ILK (hereafter called ILK-1) by only four amino acids, while the cDNA sequence diverges by 102 nucleotides, thus excluding that ILK-2 is an allelic variant of ILK-1. Expression of ILK-2 mRNA was observed in metastatic human HT-144 melanoma and HT-1080 fibrosarcoma cell lines, but not in normal human tissues. Moreover, stimulation of HT-144 cells with TGF-β1, but not with EGF, PDGF-AB or insulin, induced a selective overexpression of ILK-2 mRNA as compared to ILK-1 mRNA. Bacterially-expressed GST/ILK-2 autophosphorylated and labeled myelin basic protein as well as a recombinant GST/β3 integrin cytoplasmic tail peptide. Transfection of either ILK-2 or ILK-1 cDNA into the non-metastatic melanoma cell line SK-Mel-2, expressing exclusively ILK-1, induced anchorage independent cell growth and cell proliferation, as demonstrated by growth in soft agar. Our data provide evidence that ILK-2 is a new isoform of ILK-1 that is expressed in some highly invasive tumor cell lines but not in normal adult human tissues and whose expression is regulated by TGF-β1.

    Original languageEnglish
    Pages (from-to)3069-3077
    Number of pages9
    Issue number27
    Publication statusPublished - 22 Jun 2000


    • Integrin
    • Integrin-linked kinase
    • Melanoma phosphorylation
    • TGF-β
    • cDNA sequence


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