Growth control of human mammary cancer cells (MCF-7 cells) in culture: effect of estradiol and growth factors in serum-containing medium

The growth control of estrogen-dependent mammary cancer is very complex and only partly understood. The present study was undertaken in order to establish conditions for growth control of MCF-7 cells in monolayer culture with focus on the effect of estradiol-17 beta, fetal calf serum, and growth factors. The effect of charcoal-stripped fetal calf serum (CSFCS) on cell growth was dependent upon the presence of hormones or growth factors in the medium. In the presence of insulin (or insulin-like growth factor 1) and in the absence of estradiol-17 beta, increasing concentrations of CSFCS, 0.625-20%, produced a bell-shaped growth response curve. Serum concentrations greater than 2.5% inhibited cell growth in the absence of estradiol-17 beta, whereas CSFCS in a dose-dependent way up to 10% stimulated growth in the presence of estradiol-17 beta (5 x 10(-10) mol/liter). The growth inhibitory effect of CSFCS could not be demonstrated in the absence of insulin (or insulin-like growth factor 1) and estradiol-17 beta. CSFCS stimulated growth in a dose-dependent way in the presence of estradiol-17 beta and also in the absence of insulin. Both the putative growth inhibitor and stimulator were found to be heat stable and not dialyzable. Epidermal growth factor stimulated growth but was unable to eliminate the growth inhibitory effect of 5-10% CSFCS. Interleukin-1 alpha inhibited MCF-7 cell growth in a dose-dependent way and produced a 75% reduction in cell number at a concentration of 5 x 10(-10) mol/liter. This inhibition was almost totally overcome by estradiol-17 beta. It is concluded that serum appears to contain factors with both stimulatory and inhibitory effects on the growth of MCF-7 cells. The inhibitory effect can be eliminated by estradiol (5 x 10(-10) mol/liter). In the presence of estradiol cell growth is stimulated by CSFCS in a dose-related way up to 5-10%. Taken together these data seem to indicate that estradiol stimulates cell growth in two principal ways: partly by eliminating the effect of an inhibitor, in support of a "negative hypothesis," and partly by an effect whereby estradiol permits a growth stimulator in CSFCS to be expressed, in support of the "indirect positive hypothesis."

Influence of progestins on serum hormone levels in postmenopausal women with advanced breast cancer--I. General findings

The influence of oral high dose progestin (medroxyprogesterone acetate, MPA and megestrol acetate, MA) treatment on serum hormone levels was studied in ten postmenopausal women with advanced breast cancer. The gonadotropins and ACTH were significantly reduced by greater than 50 and 23%, respectively. Serum cortisol, DHEAS, androstenedione and testosterone were all significantly reduced (mean reduction between 64 and 76%), while serum estrone, estradiol and estrone sulfate were significantly reduced by 20-30%. Sex hormone binding globulin (SHBG) and corticosteroid binding globulin (CGB) were reduced by 68 and 25%, respectively. Although the dose of MA used (160 mg/day) was only 1/6 of the MPA dose (1000 mg/day), the mean serum level of MA was 2-fold higher than the mean serum level of MPA. MPA treatment gave a more pronounced suppression of SHBG than MA treatment, while estrone sulfate levels were more suppressed by MA. These findings suggest a differential effect of MPA and MA on certain plasma hormones, possibly of importance for understanding the mechanism of action of the two drugs. The reduction of estrone sulfate may be beneficial for the action of MA against breast cancer.

Oral high-dose progestins as treatment for advanced breast cancer

Fifty-two postmenopausal, previously treated advanced breast cancer patients who received oral high-dose progestins (medroxyprogesterone acetate [MPA] and/or megestrol acetate [MA]) were retrospectively reviewed. MPA was given to 45 patients and MA to 17 (10 earlier treated with MPA); 48 were evaluable for clinical response to progestin treatment, 43 for MPA and 5 for MA. Two complete responses and 10 partial responses (25%) with median duration of 9.5 months were seen. Forty percent of the patients obtained stable disease greater than or equal to 6 months with a median duration of 8.0 months. In patients with estradiol receptor positive (n = 31) and estradiol and progesterone receptor positive (n = 19) tumors the response rates were 35% and 37% respectively. No differences in serum levels of MPA or MA were observed in the different responding groups. The serum levels of MA were twice as high as MPA in spite of a dose of 160 mg/day of MA compared to 1,000 mg/day of MPA. A long disease-free interval, and positive receptor status of primary or metastatic lesions seemed to predict response to endocrine therapy even late in a therapeutic sequence. Side effects occurred in 11/45 (24%) of MPA treated patients and in 1/15 (7%) of MA treated patients. No difference in serum levels of MPA was found between patients with side effects and patients without side effects.

DNA ploidy and steroid receptors as predictors of disease course in patients with endometrial carcinoma

Prognostic factors for outcome of malignant disease should be based on objective assessments whenever possible, so that the results may be reproduced. In a prospective study, tumor samples from 75 patients were subjected to flow cytometric DNA analysis. Samples were also taken from 61 patients for estradiol and progesterone receptor measurements. The course of the disease was analysed with regard to ploidy and receptor status. Receptor status was significantly correlated with ploidy, as diploid tumors were more often receptor-positive or receptor-rich (greater than or equal to 30 fmol/mg protein). Mortality and recurrence rates were highest among patients with aneuploid or receptor-poor tumors. Ploidy, receptor status, histological grade, surgical stage, and myometrial invasion were found to be of significant prognostic value. By multivariate analysis, ploidy was indicated to be the best predictor, followed by surgical stage. DNA and receptor measurements are recommended in research on endometrial carcinoma, and may become useful in routine clinical work.

The distribution and prognostic implications of steroid receptors in endometrial carcinomas

Estradiol receptors (ER) were measured in 71 and progesterone receptors (PR) in 62 primary endometrial carcinomas. ER were found in 62 (87%) and PR in 56 (90%) of the tumors. Fifty-six tumors were ER+/PR+ and 4 were ER-/PR-. The frequency of receptor positive tumors was not significantly correlated to histological grade. Highly differentiated tumors were, however, more often ER and PR rich (greater than or equal to 30 fmole/mg protein) as compared to poorly differentiated tumors. The median ER and PR values for grade I tumors were also significantly higher than for grade III tumors. No significant differences were found in the frequency of patients with ER or PR rich tumors in the different FIGO or surgical stages. The receptor status was not related to depth of myometrial infiltration. Recurrence rates and death rates were significantly higher in patients with PR poor as compared to those with PR rich tumors. This prognostic information could not be shown for ER.

The influence of progestins on receptor levels in breast cancer metastasis

The influence of oral high-dose (HD) medroxyprogesterone acetate (MPA) and megestrol acetate (MA) treatment on steroid hormone receptor levels in metastatic breast tumor tissue was investigated. In ten postmenopausal women with advanced breast cancer, receptor biopsies were obtained from the same tumor before the start, and one and eight weeks after the start of oral HD progestin treatment. Endocrine treatment had been stopped in all patients at least five weeks before the start of progestin treatment. Estradiol receptor (ER) levels were reduced by 26.9% and 20.0% respectively after one and eight weeks of treatment. Progesterone receptors (PgR) were significantly reduced to undetectable levels, possibly due to MPA and MA binding to PgR. A stepwise decrease in androgen receptors (AR) was observed, indicating that the two progestins (MPA and MA) may also act through AR, and/or interfere with the replenishment of AR.

Effect of oral high-dose progestins on the disposition of antipyrine, digitoxin, and warfarin in patients with advanced breast cancer

The influence of two progestins, medroxyprogesterone acetate (MPA) and megestrol acetate (MA), given orally in high doses, on the pharmacokinetics of antipyrine, digitoxin, and warfarin were studied in patients with advanced breast cancer. Antipyrine and warfarin were given as a single test dose before and after 5 weeks of progestin treatment. The pharmacokinetics of digitoxin was investigated at steady state in patients receiving this drug therapeutically before and during treatment with progestins. Small changes in clearance rates for antipyrine, warfarin, and digitoxin were found. A minor decrease observed in warfarin clearance however may be of clinical importance. Half-lives decreased by 13% for antipyrine and increased by 71% for warfarin. High-dose progestins given orally do not seem to have a major influence on drug metabolism, probably reflecting a minor effect on drug and steroid-metabolizing microsomal mono-oxygenases in the liver.

Steroid receptor content in human ovarian tumors: survival of patients with ovarian carcinoma related to steroid receptor content

Steroid receptors were measured in 31 malignant and 29 benign or semimalignant ovarian tumors in a prospective study. Estrogen receptors (ER) were found more often in highly differentiated malignant tumors (86%) than in poorly differentiated ones (23%). No such difference was found for progesterone receptor (PR). Receptor content was not related to clinical stage. The median survival of patients with PR+ or ER+/PR+ malignant tumors was 30 and 31.5 months, respectively, compared to 10 and 9 months for those with receptor negative tumors. This positive prognostic information could not be demonstrated for ER alone. Receptor content and distribution were similar in benign and semimalignant tumors. Measurement of hormone receptors in ovarian cancers can thus give valuable prognostic information.

Steroid receptors in human endometrium. Comparison of data obtained by three different methods

To find a method for steroid receptor measurement in small endometrial tissue samples (less than 100 mg), an isoelectric focusing assay has been compared with a dextran-coated charcoal assay for oestradiol receptor. The results correlated well (r = 0.85) and this indicates that isoelectric focusing is a good technique for oestradiol receptor determination. Te isoelectric focusing of progesterone receptor has been compared with a dextran-coated charcoal assay and sucrose density gradient centrifugation. Isoelectric focusing gave recoveries of 0-26% compared to receptor values obtained with the two other methods, which correlated well (r = 0.97). The low recovery implies that the isoelectric focusing assay is not suitable for progesterone receptor determination.

Oestrone sulphatase activity of the rat uterus in different hormonal states

Oestrone sulphatase activity was determined in 12,500 g supernatant of rat homogenates. The conditions used were 0.5 mM oestrone sulphate and 30 min incubation at pH 8.0 and 37 degrees C. The enzyme activity in uteri from normal animals was found to be 5.1 +/- 0.7 nmol (mg protein)-1 h-1. In ovariectomized and hypophysectomized animals the values were significantly higher, whereas subcutaneous administration of 17 beta-oestradiol to such rats resulted in significantly decreased oestrone sulphatase activities. Progesterone increased the enzyme activity of intact rats. It is concluded that the uterine tissue of rats contains oestrone sulphatase which may be of biological importance and which is inhibited by oestrogen.