Chromosome 13 instability and esterase D expression in an osteosarcoma cell line

A TP53 mutation detected in cells established from an osteosarcoma, but not in the retinoblastoma of a patient with bilateral retinoblastoma and multiple primary osteosarcomas

A patient with bilateral retinoblastoma and subsequent multiple primary osteosarcomas has been described previously. Osteosarcoma cell lines established from this patient were shown to express a shortened RB1 mRNA transcript and no detectable normal Rb protein. We now show that the osteosarcoma cell lines have lost one TP53 allele and contain a mutation in exon 8 codon 286 [GAA to AAA (Glu to Lys)] in the remaining allele. Consequently, the osteosarcoma cell lines have no normal Rb protein and no normal p53 protein. Neither constitutional DNA nor DNA extracted from a retinoblastoma of the left eye of the patient contained the TP53 mutation, suggesting that the TP53 mutation in the osteosarcoma cells may represent a tumor-promoting mutation, which confers a selective growth advantage. If both RB1 and TP53 are involved in the initiation of osteosarcoma, the mechanisms for development of the retinoblastoma and osteosarcoma tumors are different.

Chromosome 13 alterations in osteosarcoma cell lines derived from a patient with previous retinoblastoma

Various sublines of cells established from an osteosarcoma that developed in a patient (O.H.) with previous bilateral retinoblastoma were examined for different restriction fragment-length polymorphisms of chromosome 13q, as well as for rearrangements of the retinoblastoma gene using a cDNA probe. The independently established sublines were used to help separate primary and secondary events taking place in tumorigenesis of the osteosarcoma of this patient. Information from the present DNA analysis, taken together with data from cytogenetic and enzymatic studies on chromosome 13 in the cell lines, revealed both common and distinct genetic changes on chromosome 13q. The common changes may indicate the nature of the first and second mutational events in the development of the osteosarcoma. The first, constitutional cancer predisposing mutation seemed to be a base mutation or a small deletion/insertion, and the second event involved a deletion of a larger part of the long arm of chromosome 13. The distinct genetic changes included other deletion and duplication events of chromosome 13q. The existence of multiple sublines with different genetic constitutions provides improved possibilities for gaining insight into the nature of the genetic lesions leading to tumor formation, as these may reflect the clonal variation present in the primary tumor. We also demonstrate the difficulty of inferring from single tumor cell isolates to properties of the primary tumor.

Symmetrical chromosome rearrangements in cell lines established from human radiation-induced sarcomas

We report the establishment of cell lines from six radiation-induced tumors, three osteosarcomas, and three soft tissue sarcomas. Cytogenetic analysis of the lines showed mostly balanced rearrangements in the osteosarcomas; the soft tissue sarcomas had more unstable karyotypes. The rearrangements observed were unlike those previously reported for spontaneously occurring tumors of the same histological type and were more typical of the long-term changes observed after radiation exposure.

An interspecific backcross linkage map of the proximal half of mouse chromosome 14

We have generated a 30-cM molecular genetic linkage map of the proximal half of mouse chromosome 14 by interspecific backcross analysis. Loci that were mapped in this study include Bmp-1, Ctla-1, Hap, hr, Plau, Psp-2, Rib-1, and Tcra. A region of homology between mouse chromosome 14 and human chromosome 10 was identified by the localization of Plau to chromosome 14. This interspecific backcross map will be valuable for establishing linkage relationships of additional loci to mouse chromosome 14.

Cytogenetic and quantitative DNA analysis of primary and xenografted human osteosarcomas

We have analyzed, cytogenetically and by flow DNA cytometry, three human osteosarcomas. From one case, both the primary tumor (T9) and three of its serial passages in nude mice were analyzed. From the two other tumors (T1, T4), nude mouse xenografts were examined. Complex karyotypic rearrangements were invariably found in the short-term culture preparations. The major clones were hypodiploid in T1 but near-triploid in all other tumor samples. No rearrangement common to all tumors could be identified. The DNA indexes were 1.0/2.0 (T1), 1.4 (T4), 0.9/1.8 (T9 primary), and 1.7 (all T9 xenografts). Thus, there was good correlation between the DNA indexes and the chromosome numbers. Chromosomal evolution could be studied in one case, in which both the primary tumor (T9) and its xenograft passages (1, 4, and 7), obtained 1, 7, and 11 months after the first transplantation of T9 cells to nude mice, were analyzed. All but one of the clonal marker chromosomes found in the primary tumor were retained in all passages. On the other hand, several new clonal markers developed.