Timp1 gene demethylation contributes to the anoikis resistance phenotype along melanocyte malignant transformation

摘要: 2877 Although anoikis resistance has been considered a hallmark of the malignant phenotype, causal relation between neoplastic transformation and anchorage-independent growth remains undefined. To study this correlation, we developed an experimental model murine melanocyte transformation, where different melanoma cell lines (4C3, 4C11, Tm1, Tm5) were established after submitting non-tumorigenic lineage (melan-a) to sequential substrate anchorage impediment cycles. Melan-a sublines, submitted 2, 3 4 deadhesion cycles (2C, 3C 4C), also established, showing progressive anoikis-resistance, representing distinct phases tumor progression. Previous gene expression analysis comparing adherent melan-a, melan-a maintained in suspension for 24h, Tm1 Tm5 cells, showed up-regulation Timp1 lines. initially described as MMP inhibitor, protein recently associated with human breast cells. increases along tranformation its possible association prompted us investigate whether is regulated by DNA methylation it acquisition anoikis-resistant phenotype. While cells express low levels Timp1, all derived from high protein. After 5AZAdC treatment, increased mRNA observed suggesting that these promoter hypermethylation. Ms-SNuPE shown demethylation first exon carcinogenesis. Overexpression resulted survival conditions, but overexpression itself was unable transform melanocytes into tumor-forming In addition, latency time appearance reduced Timp1-transfected indicating molecule may be aggressiveness. conclusion, our results show increment process, resulting demethylation, which causally increase anoikis-resistance not acquisition, itself, fully transformed