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

Abstract

Using a series of tumorigenic and non-tumorigenic somatic cell hybrids that resulted from the fusion of the human osteosarcoma cell line OHS50-P16T (P16T) with the HeLa cell line D98OR, we investigated the role that genetic mutations, including alterations of oncogenes, tumor suppressor genes, and chromosomes, play in P16T tumorigenicity. Analysis of a previously identified oncogene mutation, c-myc amplification, in the P16T cell line demonstrated that both the tumorigenic and non-tumorigenic hybrids contained the amplified c-myc gene. Analysis of previously identified P16T tumor suppressor gene alterations, p53 mutation, and loss of RB1 expression demonstrated that the mutated p53 gene was selectively maintained in both the non-tumorigenic and tumorigenic hybrids, whereas loss of RB1 expression was not maintained 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 tumorigenic and non-tumorigenic hybrids. Loss of HeLa D98OR chromosome 22, with maintenance of P16T chromosome 22, was observed in the tumorigenic hybrids, a result confirmed by LOH analysis, which demonstrated the specific loss of HeLa chromosome 22 genetic material in the tumorigenic segregants. Together, these results demonstrated that amplified c-myc, mutant p53, and RB1 genes seem to be important in osteosarcoma tumorigenicity and that an additional altered gene or genes on chromosome 22 may play a key role in osteosarcoma tumorigenicity.

Isolation and characterization of human cells resistant to retrovirus infection

“…These drugs select against the expression of the HPRT and APRT gene products since expression of these proteins results in the incorporation of the toxic purine analogues into DNA. The genes coding for these enzymes (HPRT X-chromosome and APRT human chromosome 16) are diploid and possibly polyploid in HeLa cells [14]. Table 1 shows the kinetics of the appearance of 6-TG and DAP resistant colonies after 7 rounds of mutagenesis.…”

ATRX Alteration Contributes to Tumor Growth and Immune Escape in Pleomorphic Sarcomas

“…But only three genes came out to be recurrently mutated (considering point mutations only), as also showed by the TCGA study [ 6 ]: TP53 , RB1 , and ATRX (mutated in 48.7%, 17.9%, and 12.8%, respectively). RB1 [ 7 , 8 ] and TP53 [ 9 , 10 ] are tumor suppressor genes that have long been known to be implicated in the oncogenesis of pleomorphic sarcomas. ATRX is a chromatin modifier gene with a Swi/Snf2 domain [ 11 ].…”

ATRX alteration contributes to tumor growth and immune escape in pleomorphic sarcomas

“…But only three genes came out to be recurrently mutated (considering point mutations only), as also showed by the TCGA study (The Cancer Genome Atlas Research Network et al, 2017): TP53, RB1 and ATRX (mutated in 48.7%, 17.9% and 12.8% respectively). RB1 and TP53 are tumor suppressor genes that have long been known to be implicated in the oncogenesis of pleomorphic sarcomas (Calo et al, 2010;Isfort et al, 1999;Pérot et al, 2010;Rubio et al, 2010). ATRX is a chromatin modifier gene with a Swi/Snf2 domain (Gibbons et al, 1995).…”