Over expression of Capping protein Z line alpha 1(CAPZA 1) and protein phosphatase 1 (PP 1) in malignant melanoma as identified by subtractive hybridization

Abstract

7518 Background: Several genetic alterations have been implicated in the development of melanoma. However the expression of oncogenes, tumor supressor, mismatch repair and apoptosis related genes and their interactions in melanoma have not been completely clarified. We sought to identify the unique genes that are specifically implicated in the development of progressive forms of melanoma. Methods: Nine Malignant melanoma cell lines and one primary culture of pure normal human skin melanocytes were used in subtractive hybridization. Total RNA was isolated from cell lines and primary cell cultures. Poly-A RNA was purified and cDNA was synthesized. A two-step hybridization was performed and the differentially expressed sequences were amplified. The sequences were cloned in a vector and the fragments were sequenced. Fragments showing high homology with previously described sequences were considered to represent known genes. Results: Multiple genes were found to be underexpressed and a large number were overexpressed between the different cell lines and the normal skin melanocytes. Capping Protein z-line alpha 1 (CAPZA1), protein Phosphatase 1 (PP1), clone CTB-89H12 and FLJ 13207 were identified to be over expressed genes in melanoma cell lines. Melanocyte specific protein (Pmel17) and Mitochondrial carrier (adenine nucleotide translocator) were identified to be underexpressed in melanoma cell lines. Underexpression of Pmel17 on subtractive hybridization was not confirmed on the RT-PCR analysis of individual cell lines. CAPZA1 and PP1 were further found to be overexpressed in the melanoma cell lines with minimal expression in melanocytes on RT-PCR analysis of all the samples. Conclusions: The selective over-expression of CAPZA 1 and PP 1 is associated with malignant melanoma and may represent valuable candidate genes in the further management of this disease. No significant financial relationships to disclose.