New established melanoma cell lines: genetic and biochemical characterization of cell division cycle

Cancer might be envisaged as the result of a genetic process causing the unregulated proliferation of a given cell as well as its inability to undergo differentiation and/or apoptosis. Alterations of genes regulating cell division cycle appear to play a key role in the development of human cancer.

On the bases of the above considerations, we decided to establish new cell lines from human melanoma specimens, in order to analyse the molecular alterations in primary preparations of malignant cells.

The present paper describes two new established cell lines and their genetic and biochemical features. Both the melanoma cell lines show inactivation of the cyclin-dependent kinase inhibitor gene, CDKN2A/p16INK4A, thus demostrating that this alteration occurs in primary human melanomas. No other alterations were observable when we investigated several different cell cycle genes including those encoding cyclins, cyclin-dependent kinases and cyclin-dependent kinase inhibitors. Analyses at protein level by means of immunoblotting confirmed the results obtained at the genetic level. Moreover, the inducibility of a pivotal cyclin-dependent kinase inhibitor gene, namely p21CIP1 gene, was obtained by treating the cells with histone deacetylase inhibitors, namely butyrate and phenylbutyrate.

Our results suggest a primary role of cyclin-dependent kinase inhibitor genes inactivation in the origin of human melanoma and allow the proposal of new therapeutic strategies based on the transcriptional activation of p21CIP1 gene.