COMPARISON OF SPONTANEOUSLY TRANSFORMED XERODERMA PIGMENTOSUM CELLS AND PARTIALLY TRANSFORMED HUMAN DIPLOID CELLS BY X-IRRADIATION

Abstract

One of the xeroderma pigmentosum (XP) complementation group C strains transformed spontaneously when the cells were subcultured regularly. We observed four kinds of partially transformed phenotypes such as increased lifespan, anchorage-independent (Al) growth, morphological change and forcus formation in this XP-C cultures. On the other hand, only one or two kinds of transformed phenotypes was seen in the partially transformed normal human cells by X-irradiation. Among these four kinds of transformed phenotypes, increased lifespan is associated with the specific chromosomal rearrangements, however, Al growth phenotypes showed normal diploid Karyotype by G-banded analysis. We examined the oncogene expression in the partially transformed XP-C and normal human cell clones to study the relationship between specific cancer phenotypes and the corresponding oncogene expression. An elevated expression of the Blym gene was observed in the partially transformed XP-C cells but not in the other cells. However, we did not observe specific change of oncogene expression corresponding to specific cancer phenotype in our partially transformed cells. Oncogene may contribute in a variety of ways to conversion of a normal cell into a tumor cell.