Ras and neu oncogenes reverse serum inhibition and epidermal growth factor dependence of serum‐free mouse embryo cells

Abstract

Serum-free mouse embryo cells, cultured in basal nutrient medium supplemented with insulin, transferrin, epidermal growth factor, fibronectin, and high-density lipoprotein, do not exhibit growth crisis, lack detectable chromosomal aberrations, are nontumorigenic in vivo, are dependent on epidermal growth factor for survival, and are growth inhibited by serum or platelet-free plasma. These cells after transfection with the human Ha-ras or rat neu oncogenes no longer required epidermal growth factor for survival, were tumorigenic in vivo, and also proliferated in serum-containing medium. Autocrine activity capable of replacing epidermal growth factor was detected in conditioned medium from ras-transformed cultures, but little such activity was detected in medium from neu-transformed cultures. In addition, the capability of ras or neu-transformed cells to grow in serum-containing medium could not be mimicked in untransformed cells by the addition of growth factors or conditioned medium from transformed cells. These results suggest that the known structural similarity of the neu gene product to the EGF receptor is also reflected in a functional similarity by which the mutationally activated neu protein can replace the ligand-activated EGF receptor. These results also suggest that the ability of ras- and neu-transformed cells to escape the effect of the inhibitory serum activity is a nonautocrine property distinct from the acquisition of EGF autonomy.

Serum and transforming growth factor beta regulate glial fibrillary acidic protein in serum-free-derived mouse embryo cells.

“…SFME cells also depend on EGF for survival, and cycloheximide or actinomycin D prevents death from EGF deprivation (5), suggesting that cell death requires the synthesis of RNA and protein, a phenomenon of programmed cell death similar to that reported for neuronal cell death in the absence of nerve growth factor (NGF) (9). In addition, proliferation of SFME cells is reversibly inhibited by serum or platelet-free plasma (1,4,6), and thus these cells would not be propagated under conventional culture conditions using serum-supplemented medium. As for most mouse embryo cell lines, the precise nature of the cells giving rise to the continuously growing SFME cultures was unknown.…”

“…Initiation and culture ofBALB/c SFME cells from 16-day-old embryos and preparation of medium supplements have been described (1)(2)(3)(4)(5)(6). Medium was Dulbecco's modified Eagle's medium/F-12,1:1 (24,25).…”

“…Cells with properties similar to SFME cells were also isolated from adult mouse brain. These results suggest a role for transforming growth factor (3 in astrocyte differentiation in developing organisms and in response to injury and identify the cell type that has the unusual properties of SFME cells.Serum-free mouse embryo (SFME) cells initiated and maintained multipassage in a rich basal nutrient medium supplemented with insulin, transferrin, epidermal growth factor (EGF), high-density lipoprotein, and fibronectin display several distinctive properties (1)(2)(3)(4)(5)(6). Mouse embryo cells derived in conventional serum-supplemented medium undergo a period in which proliferative potential is lost or reduced, and then genetically altered cells with indefinite proliferative potential emerge (2,7,8).…”

6-(Methylsulfinyl)hexyl Isothiocyanate Isolated from Wasabi(Wasabia japonica MATSUM)Suppresses Tumor Progression in an Experimental Mouse System

“…Cell and culture A tumor cell line, r/mHM-SFME-1, was originally derived from mouse embryonic fibroblast SFME (Loo et al, 1987) and established by the introduction of activated hu-E-mail: fuke@tmca.ac.jp man c-Ha-ras and myc genes (Nomura et al, 1993;Shirahata et al, 1990). Cells were cultured with a mixture of Hames F12 and Dulbecco's modified Eagle medium (F/D, 1 : 1) (Sigma, St. Louis, MO) supplemented with 10% fetal bovine serum (FBS: Cosmo Bio Co., Tokyo) in 5% CO 2 at 37˚C.…”

Phospho-Signaling at Oocyte Maturation and Fertilization: Set Up for Embryogenesis and Beyond Part I. Protein Kinases

“…However, the activated p185 Neu tyrosine kinases are not able to mimic the EGFstimulated EGF receptor tyrosine kinase in triggering oocyte maturation, which suggests that the EGF receptor and the p185 Neu tyrosine kinase do not work in the same pathways in Xenopus oocytes (Narasimhan et al 1992). But in mouse embryo culture cells, it was shown that mutationally activated Neu protein can substitute the ligand-activated EGF receptor activity to reflect the structural similarity and EGF induced phosphorylation and regulation of p185 Neu (Kokai et al 1988;Shirahata et al 1990). …”