Nonsteroidal serum factors involved in the regulation of the proliferation of canine prostatic epithelial cells in culture

Abstract

Canine prostatic epithelial cells were cultured in primary monolayers in order to define those factors that induce a proliferative response at the cellular level. Cultures were performed in a serum-free medium or in a medium supplemented either with fetal bovine serum or dog serum in the presence or absence of several sex steroids (androstenedione, testosterone, dihydrotestosterone, 3 alpha- and 3 beta-androstanediols, epitestosterone, epidihydrotestosterone, estrone, estradiol, and progesterone). Cell proliferation was observed in the absence of serum and exogenous steroids. The rate of cell division was serum dependent and steroid independent. Pretreatment of sera with charcoal had no effect on their mitogenic activities. Cells maintained in an endocrine milieu prior to tissue dispersion and throughout the whole procedure proliferate to the same extent as those deprived of hormones, whether free of serum or added supplements. The addition of insulin (2 micrograms/ml), dog prolactin (up to 25 ng/ml) and zinc (10(-8) to 10(-2) M) in a serum-free medium did not induce cell responsiveness to steroids. Dihydrotestosterone, 3 alpha-androstanediol, and estradiol alone or in combinations known to induce the growth of the canine prostate in vivo were ineffective in vitro. The proliferative responses to sera were time and concentration dependent, and dog serum was more potent than fetal bovine serum. Thus, humoral factors other than steroids, prolactin, insulin, or zinc may be of importance in the activation of epithelial cells involved in the development of prostatic hyperplasia and adenocarcinoma.

Serum and prostatic growth‐promoting factors for steroid‐independent epithelial cells of adult dog prostate

“…In some instances, other culture media (199, Dulbecco, MEM) were used and led to similar results. The procedure used for cell harvesting and determination of cell numbers with a Coulter Counter, model ZF, was already described [8]. Results were either expressed as the mean number of cells 2 standard deviation of the mean for triplicate cultures or in percentages of increase in cell proliferation.…”

“…The total volume (V,) was calculated from the dimensions of the column. static epithelial cells in primary cultures and reinforce our earlier conclusion of their steroid unresponsiveness [8,9]. Indeed, inhibitors of sex steroid action, namely the antiandrogens Anandron and Cyproterone Acetate which are very potent competitors of the specific binding of Methyltrienolone to these prostatic epithelial cells [ 101, were unable to prevent their growth.…”

“…In order to study their effects on epithelial cell proliferation, all components and column fractions were resuspended in serum-free medium (at concentrations indicated in Table I and Fig. 5) and then added to the established primary cultures (day 3) for a further incubation period of 5 to 7 days [8]. The agents tested were EGF, bFGF, aFGF, IGF-I, tissue culture serum factor, calpeptide, bombesin, canine prolactin, hGH, GnRH, TRH, HCG, PMSG, insulin, bradykinin and its analogs as well as bradykinin potentiator P, kallikrein, arginine-vasopressin, lysolecithin, selenite (Na,SeO,), zinc (ZnCl,), and phenol red.…”

“…IB) or freshly isolated epithelial cells (not shown). As demonstrated earlier for DS [8], and herein for prostatic extracts (Fig. lB), the mitogenic activities of both preparations were not altered by charcoal treatment.…”

“…lB), the mitogenic activities of both preparations were not altered by charcoal treatment. It has already been reported that cultures supplemented with 10% charcoal-treated DS or dFBS contain less than lo-'' M concentrations of androgens or estrogens [8].…”