Expression of a Phenotype of Normal Differentiation in Cultured Mammary Glands is Promoted by Epidermal Growth Factor and Blocked by Cyclic Adenine Nucleotide and Prostaglandins

Epithelial mouse mammary cell line exhibiting normal morphogenesis in vivo and functional differentiation in vitro.

“…Eight and 6 transplants were examined 4 wk after transplantation derived from passages 7 and 11, respectively. Thirteen of 14 importantly, form ducts upon injection into their normal environment-i.e., the mammary fat pad. Furthermore, preliminary observations demonstrate that the cells contain desmosomes by transmission electron microscopy (data not shown) and synthesize a mouse mammary tumor virus-specific antigen with an estimated Mr of 67,000 (unpublished observations).…”

“…Cell suspensions taken from virgin mice and embedded into collagen gels can be induced to synthesize casein polypeptides by the addition of hormones to the growth medium (14,15). COMMA-1D cells were embedded within a collagen (type I) matrix in vitro to determine inducibility of casein synthesis.…”

“…The cultures were allowed to incubate at 370C for an additional week, during which time the medium was changed daily. For analysis of casein synthesis, the cells were dissociated from the collagen matrix by collagenase treatment and extracted with 8 M urea buffer (14). The proteins in the cell extract were separated on 10% polyacrylamide gels; then specific casein polypeptides were identified by using rabbit antiserum prepared against purified mouse caseins (15) and the immunoblot procedure for gel-fractionated proteins (17,18).…”

Factors controlling proliferation and differentiation of canine thyroid cells cultured in reduced serum conditions: effects of thyrotropin, cyclic AMP and growth factors

“…The thyroid cells which have grown with EGF remain determined to respond to TSH by the stimulation of thyroid-specific functions. In a few in vitro systems, EGF acts as a hormone modulating various differentiated functions dissociable from the mitogenic response, as well as the response to other hormones: increased synthesis of collagen or fibronectin (Kumegawa et al, 1982;Chen et al, 1977), inhibition of the induction of gonadotropin receptors (Ascoli, 1980) and of the stimulation by gonadotropin of the production of estrogens in granulosa ceils or of testoterone in Leydig cells (Hsueh et al, 1981), stimulation of the production of progesterone in granulosa cells {Jones et al, 1982), modulation of the casein synthesis in mammary cells (Tonelli and Sorof, 1981;Taketani and Oka, 1983). There is a great analogy between our results and the effect of EGF on pituitary GH, cells.…”

Mammary Gland Neoplasia in Long-Term Rodent Studies

“…In general, estrogens are responsible for growth of mammary ducts and progesterone is necessary for lobuloalveolar growth in the mouse (72); however, a direct mitogenic effect of estrogens on the mammary gland has not been clearly demonstrated (73). A postulated mechanism is that estrogens stimulate secretion of growth factors such as EGF (74) or other growth factors of mammary or extramammary origin that might sensitize the mammary gland to mitogenic factors (73,75 (76,77). The mammogenic effects of ovarian steroids are largely dependent on the integrity of the pituitary gland, because the effects of estrogen and progesterone cannot be demonstrated in hypophysectomized animals (78).…”