title: Normal rat intestinal cells IEC-18: characterization and transfection with immortalizing oncogenes.
abstract: IEC-18 cells, a cell line derived from the ileum of rat intestine, have the characteristics of normal cells since they have a contact inhibited cell growth, do not form colonies in soft agar and are not tumorigenic when injected in nude mice. IEC-18 cells were transfected with nuclear oncogenes, c-myc, v-myc and SV40 T antigen in order to obtain immortal cell lines. Independent clones were isolated and characterized for the growth properties. Expression of v-myc altered the morphology of the cells and shortened the doubling time. A slow growth together with a low cloning efficiency was associated with the expression of SV40 T antigen. No changes either in growth or in morphology were observed in c-myc-expressing IEC-18 cells. Expression of these nuclear oncogenes did not result in the neoplastic transformation of the IEC-18 cells, since none of the clones lost the anchorage dependence or were able to form tumors in vivo. The c-myc-containing IEC-18 cells were unable to secrete in the growth medium TGF α and exposure to TGF β inhibited the growth rate by 30%. All these observations are consistent with the conclusion that the expression of nuclear oncogenes does not lead to the neoplastic transformation of these cells.
authors.affiliation: Laboratory of Comparative Toxicology and Ecotoxicology, Istituto Superiore di Sanita', Viale Regina Elena 299, 00161, Roma, Italy.
authors.forename: O
authors.initials: O
authors.lastname: Vincentini
authors.forename: C
authors.initials: C
authors.lastname: Ciotta
authors.forename: M
authors.initials: M
authors.lastname: Bignami
authors.forename: A
authors.initials: A
authors.lastname: Stammati
authors.forename: F
authors.initials: F
authors.lastname: Zucco