Detection of amplification of a chromosomal fragment at 6p21 including the cyclin D3 gene in a glioblastoma cell line by arbitrarily primed polymerase chain reaction

DNA from 10 human glioma cell lines was analyzed by arbitrarily primed polymerase chain reaction. By fingerprinting of the DNA fragments obtained, the presence of fragment Qx with an abnormal signal was detected in one of the glioblastoma cell lines, CCF-STTGI. The nucleotide sequence of this fragment of 387 base pairs showed no homology with any known sequences. Southern-blot analysis using Qx as a probe revealed that the abnormal signal was caused by amplification of DNA by about 50-fold. By analysis of radiation hybrid panels, the fragment was shown to be derived from a chromosomal region on 6p21. The cyclin D3 (ccnd3) gene and an EST locus, H40682, both of which were located in this region, were amplified by about 50-fold in this cell line. Two other loci, R75654 and M78872, flanking the Qx, CCND3 and H40682 loci, were not amplified, suggesting that the size of the amplicon was less than 62 cR. Since overexpression of the ccnd3 gene, but not the H40682 locus, was detected in the cell line CCF-STTGI, the increased amounts of cyclin D3 caused by gene amplification could be involved in the development and/or progression of this glioblastoma.