EXTENSIVE GENETIC-HETEROGENEITY IN THE NEUROBLASTOMA CELL-LINE NB(TU)1

A neuroblastoma cell line displaying genetically unique features was e stablished from a stage III case of a 20-month-old girl, Southern blot ting by the probe pTNB6, which contains exon I of the N-myc gene, show ed that the primary tumor had in total 4 aberrant bands beside the nor mal amplified band. The established cell line NB(TU)I had an aberrant N-myc band (9.0 kb) in addition to the normal band (2.9 kb). Cytogenet ic analysis revealed that NB(TU)I has a composite karyotype composed o f at least 7 related karyotypes, which are pseudo-diploid and contain complex chromosomal abnormalities, including translocations, deletions and homogeneously staining regions (HSRs). Such extensive abnormaliti es were considered to be prominent among known neuroblastoma cell line s, and it was suggested that NB(TU)I had acquired a certain type of ge netic instability. Analysis of N-myc bands in II clones of NB(TU)I sho wed that the intensity ratio of the normal-sized band (2.9 kb) and the aberrant one (9.0 kb) markedly varied among clones, Moreover, 3 clone s showed an additional band with the size of 3.7 kb, which was detecta ble neither in the parent NB(TU)I nor in the primary tumor. Thus, NB(T U)I was shown to be composed of heterogeneous cell components. To furt her detect such ongoing chromosomal instability, we examined micronucl ei formation. NB(TU)I yielded a larger number of micronuclei than 5 ot her neuroblastoma cell lines, We conclude that NB(TU)I has acquired ge netic instability detectable by both Southern blotting and cytogenetic analysis. (C) 1997 Wiley-Liss, Inc.