FAK (Focal Adhesion Kinase) is a non-receptor tyrosine kinase protein implicated in integrin-mediated signal pathways. The human gene fak is located on chromosome 8q near c-myc. Cells that overexpress FAK show increased migration and increased cell survival with apoptosis inhibition. The aim of the present study was to investigate the genomic or post-genomic origin of this overexpression in seven tumor cell lines with different levels of FAK expression: K562, an erythroblastic cell line; U937, a monoblastic cell line; KG1a, a poorly differenciated myeloblastic cell line; HL 60, a promyelocytic cell line; Jurkat, a lymphoblastic cell line; A549, a bronchial adenocarcinoma cell line; M4Beu, a lymph node metastasis melanoma cell line. Total or partial chromosome 8 qualitative or quantitative abnormalities and the presence of double minute chromosomes bearing coding genomic DNA fragments were investigated using both conventional cytogenetic (standard karyotype after R- and G- banding) and molecular cytogenetic such as multicolor karyotype (M-FISH), FISH and comparative genomic hybridization (CGH). The mRNA expression was investigated using quantitative real time RT-PCR and the protein level using immunocytochemistry and western blot (immunoblot) analysis. Except for the Jurkat cell line, karyotypes revealed complex modifications. FISH and M-FISH allowed to precisely identify the chromosomal origin of the genomic material on each chromosome and CGH allowed to characterize relative loss and gain of coding genomic DNA and to identify their chromosomal origin. Summarized results are shown in the following table: No detectable RT-PCR product was observed for HL60 and U937 cell lines. The preliminary results show that there was usually a good correlation between PCR data and western blot analysis. However, FAK overexpression for KG1a cell line most probably has a genomic origin, while in K562 and A549 cell lines the origin is most probably at the transcription or post-transcription level without any abnormality of chromosome 8. Dysregulation of fak gene is observed in hematopoietic as well as solid tulor cell lines, and may contribute to leukemogenesis.</CENTER> Cell line FISH 8q24-qter CGH Chr. 8 RT-PCR RT-Q-PCR Western blot RT-Q-PCR results in copy number ratio K562 Normal Normal + 130.1 ++++ KG1a Amplified enh(8)(q11qter) + 37.5 ++++ Jurkat Normal Normal + 8.7 + (low) U937 Normal enh(8)(pterqter) 0 0 0 HL60 Amplified amp(8)(q23-24) 0 0 0 M4Beu Normal Normal + 43.5 0 A549 Normal Normal + 46 ++++
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