DEVELOPMENT AND CHARACTERIZATION OF PEDIATRIC OSTEOSARCOMA XENOGRAFTS

Abstract

Of 33 surgical specimens of osteosarcoma obtained from 24 patients, eight were established as transplantable tumor lines in immune-deprived CBA/CaJ inbred mice. Each line retained the histological characteristics of the corresponding primary tumor and produced human lactate dehydrogenase isozymes. Volume doubling times, which ranged from a mean of 12.3 .+-. 5.6 to 39.3 .+-. 9.8 days, were stable for individual lines over multiple passages. Flow cytometric analysis indicated similar cellular DNA content values in the primary human tumors and established xenograft lines; the presence of two separate stem lines, as in the original tumors, was observed in the laboratory models. Comparison of two methods of immune deprivation indicated that thymectomy, whole-body irradiation, and bone marrow reconstitution was associated with a higher rate of successful engraftment than was thymectomy, 1-.beta.-D-arabinofuranosylcytosine treatment, and whole-body irradiation. Bone marrow-reconstituted mice also showed less variability in tumor volume doubling time. We conclude that osteosarcoma can be heterotransplanted into bone marrow-reconstituted mice with a relatively high success rate and that the xenografts retain features characteristic of the tumors of origin. The availability of these models should-prove useful in the development of new therapeutic regimens and in understanding the biology of osteosarcoma.