GP130(RB13-6)-POSITIVE NEURAL PROGENITOR CELLS ARE SUSCEPTIBLE TO THEONCOGENIC EFFECT OF ETHYLNITROSOUREA IN PRENATAL RAT-BRAIN

Proliferation-competent rat brain precursor cells of glial lineages ar e thought to preferentially undergo malignant transformation after tra nsplacental exposure to ethylnitrosourea (EtNU), We recently have repo rted that monoclonal antibody (mAb) RB13-6 recognizes a developmentall y regulated 130 kDa cell surface glycoprotein (gp130(RB13-6)) transien tly expressed by a small subpopulation of glial progenitor cells in pr e-natal rat brain. The expression of gp130(RB13-6) has now been analys ed immunocytochemically in malignant gliomas induced on day 15, 18 or 21 of gestation and in long-term cultures of fetal brain cells (FBC) i solated after in vivo-exposure to EtNU on day 18 of gestation, Maligna nt gliomas induced at different gestational stages contained varying p roportions of gp130(RB13-6)-positive cells, whereas a subpopulation of proliferative neural progenitor cells exhibiting sustained gp130(RB13 -6) expression persisted in long-term FEC cultures after 3 months. Thi s subpopulation, which was not selected for in control cultures of FBC derived from buffer-treated rats, gave rise to malignant cell lines a fter a period of time similar to the latency period required for gliom a development in vivo, These data suggest that gp130(RB13-6)-positive cells of the immature rat nervous system may represent a subset of neu ral progenitor cells particularly susceptible to the oncogenic effect of EtNU.