Analysis of oncogene, tumor suppressor gene, and chromosomal alterations in HeLa x osteosarcoma somatic cell hybrids

Using a series of tumorigenic and non-tumorigenic somatic cell hybrids that resulted from the fusion of the human osteosarcoma cell line OHS50-P16T (P 16T) with the HeLa cell line D98OR, we investigated the role that genetic m utations, including alterations of oncogenes, tumor suppressor genes, and c hromosomes, play in P16T tumorigenicity. Analysis of a previously identifie d oncogene mutation, c-myc amplification, in the P16T cell line demonstrate d that both the tumorigenic and non-tumorigenic hybrids contained the ampli fied c-myc gene. Analysis of previously identified P16T tumor suppressor ge ne alterations, p53 mutation, and loss of RE? expression demonstrated that the mutated p53 gene was selectively maintained in both the non-tumorigenic and tumorigenic hybrids, whereas loss of RE I expression was not maintaine d in either the non-tumorigenic or tumorigenic hybrids. Chromosomes 11, 13, 17, and 22 were analyzed for loss of heterozygosity (LOH) to characterize the status of these previously described chromosomal alterations in the tum origenic and non-tumorigenic hybrids. Loss of HeLa D98OR chromosome 22, wit h maintenance of P16T chromosome 22, was observed in the tumorigenic hybrid s, a result confirmed by LOH analysis, which demonstrated the specific loss of HeLa chromosome 22 genetic material in the tumorigenic segregants. Toge ther, these results demonstrated that amplified c-myc, muta nt p53, a nd RE I genes seem to be im porta nt in osteosarcoma tumorigenicity a nd that an additional altered gene or genes on chromosome 22 may play a key role in o steosarcoma tumorigenicity. (C) 1999 Wiley-Liss, Inc.