Hormone receptors and enzymatic activities in human endometrial adenocarcinoma.

The hormone sensitivity of endometrial carcinoma is related to the presence of steroid hormone receptors. The determination of progesterone receptors has been proposed in order to predict clinical prognosis and to aid treatment selection. The integrity of the hormone receptor system and postreceptoral events in tumors is essential to endocrine therapy response. Nevertheless, although hormone receptors are present in a large number of endometrial carcinomas, only 30% of cases respond to hormone therapy. In some neoplasms the receptors can be present, but not functioning, or else neoplastic transformation could have induced alterations in processes after hormone-receptor interaction.

Effects of interferon-beta on steroid receptors, prostaglandins and enzymatic activities in human endometrial cancer.

Steroid receptors, prostaglandin output and enzymatic activities were determined in explants derived from human endometrium exposed to natural interferon-beta (IFN-beta). Receptors and cell metabolism were evaluated before culturing the tissue fragments and after a 3-day treatment with varying concentrations of IFN-beta. Total steroid receptor levels were unchanged when explants were set up, but there was a redistribution of both estrogen and progesterone receptors (ER and PR). A decrease in cytoplasmic receptors corresponded to an increase in receptor molecules within the nucleus. Treatment with low concentrations of IFN-beta caused a significant enhancement (p < 0.05) of ER and PR in neoplastic endometrium. In basal conditions the ratio between prostaglandin F2 alpha (Pgf2 alpha) and prostaglandin E2 (PgE2) was higher in normal than in neoplastic endometrium. The addition of low concentrations of IFN-beta to the culture medium determined a significant increase (p < 0.02) in PgF2 alpha and a parallel increase in the above ratio in neoplastic tissue, while no variation was found in normal endometrium. Analysis of the results concerning the variations in hormone-related enzymatic activities due to IFN-B revealed a significant increase (p < 0.05) in 17 beta-hydroxy-steroid-dehydrogenase (17 beta-HSD) activity. The data presented here indicate that treatment with IFN-beta modifies those biological characteristics of neoplastic cells which are involved in hormone-responsiveness.

Interferon-beta increases the sensitivity of endometrial cancer cells to cell-mediated cytotoxicity.

Established monolayer cell lines derived from human endometrial carcinoma (Ishikawa and HEC-50) were sensitive to the cytotoxic activity of peripheral blood lymphocytes (PBLs). The percentages of hormone-responsive Ishikawa cells lysed by the cytotoxic activity of lymphocytes were 45.7 +/- 4.3 (mean +/- SE), 31.5 +/- 4.1, and 20.1 +/- 1.6, at effector/target (E/T) ratios of 50:1, 25:1, and 12:1, respectively. Values of 44.7 +/- 5.4%, 29.4 +/- 4.6%, and 20 +/- 4.9% were obtained when non-hormone-responsive HEC-50 cells were used as targets at the same E/T ratio. The percentages of epithelial and stromal cells, isolated from human endometrial cancer, lysed by the cytotoxic activity of lymphocytes were 40 +/- 5.4 and 25.2 +/- 3.8, respectively, at an E/T ratio of 25:1. The addition of interferon-beta (IFN-beta) to the culture increased tumor target cell sensitivity to the lytic activity of untreated PBL. The increase produced by 10 IU/ml of IFN-beta ranged between 0.60- and 0.89-fold (P < 0.01 Student's t test, two-tailed, unpaired) in Ishikawa cells and between 0.37- and 0.72-fold P < 0.05) in HEC-50 cells. Higher concentrations of IFN-beta (100 and 1000 IU/ml) were less effective in increasing the sensitivity of the target cells. There was no significant increase in the cytotoxic activity of lymphocytes treated with IFN-beta whereas cytotoxic activity toward untreated tumor target cells increased when lymphocytes were treated with IFN-alpha. The effects of IFN-beta were also evaluated using epithelial and stromal cells derived from human endometrial cancer. It was found that IFN-beta at low concentrations (10 IU/ml) significantly increased the sensitivity of both epithelial and stromal cells, by 48 and 73%, respectively. Our data indicate that Ishikawa, HEC-50, epithelial, and stromal cells may provide a useful experimental model for studying the effects of immunomodulant agents such as IFN-beta in hormone-related tumors. IFN-beta increases endometrial target cell sensitivity, rather than the lytic activity of lymphocytes.

Antimitotic effects of usnic acid on different biological systems.

Usnic acid is a biosynthesis product characteristic of several epiphytic lichens such as Evernia, Cladonia and Parmelia. Usnic acid has several interesting biological properties. It is an antibiotic and it also seems to exert an antimitotic action. It has even been postulated that usnic acid can play a role as an environmental indicator, since its concentration varies according to the presence of toxic agents. A series of tests have been run on different biological systems such as fungi, yeasts, plant cells and neoplastic human cell cultures in order to make a general evaluation of the properties of usnic acid and to highlight any analogy between its effects on phylogenetically distant organisms. The results obtained confirm some of the already known properties of usnic acid and identify concentration ranges that are active against cells from different organisms. Furthermore, at low concentrations, the acid displays a capacity to stimulate cell metabolism in some of the biological systems tested.

Hormone receptor status in human endometrial adenocarcinoma.

Steroid receptor levels were determined in 196 samples of endometrial adenocarcinoma: cytosol estradiol receptors (ERc) were measured in 171 samples, cytosol progesterone receptors (PRc) in all samples; nuclear estradiol receptors (ERn) and nuclear progesterone receptors (PRn) in 68 samples; total estradiol receptors (ERt = ERc plus ERn) and total progesterone receptors (PRt = PRc plus PRn) were measured in 68 samples. The ERc levels were 88.2 +/- 8.9 (mean +/- SEM) and ERn were 94.4 +/- 15.6 fmol/mg protein; PRc levels were 197.9 +/- 25.9 and PRn 178.3 +/- 55.9 fmol/mg protein. The ERt levels were 162.6 +/- 23.2 and PRt 249.8 +/- 75.7 fmol/mg protein. The presence of PRc was related to the ERc levels according to the cut-off used. Estradiol receptors (ER) and progesterone receptors (PR) were present in the cytoplasmic and nuclear fractions in 60.2% and 36.8% of cases, respectively. The simultaneous presence of both ERt and PRt was observed only in 27.9% of cases. In the normal endometrium ERc and PRc were negatively correlated (r = -0.525, P less than 0.005), whereas in endometrial adenocarcinoma the correlation was positive (r = 0.491, P less than 0.001). In contrast with the normal endometrium the correlation between ERc and ERn was positive (r = 0.582, P less than 0.001) in tumor tissue. In neoplastic tissue Scatchard analysis showed a single class of specific ERc sites with a dissociation constant (Kd) of 1.39 +/- 0.8 X 10(-9) mol/l, one tenth of that found in the normal premenopausal endometrium. Qualitative and quantitative analysis of the receptor status showed that in 30% to 40% of cases studied the behavior of the neoplastic cell was similar to that found in the normal endometrial cell. In a 4-year follow-up of patients affected by endometrial adenocarcinoma there is better survival in the groups of patients with a simultaneous presence of ERt and PRt than in the group with their absence.

Oxytocin receptor in human fetal membranes at term and during labor.

Human fetal membranes, taken from 30 patients submitted to caesarean section during the final stages of gestation and labor, were examined in order to evaluate the presence and characteristics of the oxytocin receptor. The presence of oxytocin receptors in human fetal membranes, both in the amnion and in the chorion-decidua, was demonstrated in this study. The receptor binding to oxytocin showed a significant increase during early and advanced labor compared with before the onset of labor. When the pre-labor level was taken as the normalized form (control = 100) the increase with respect to the control (10 cases) for the amnion in early labor (2.27 times +/- 0.11, mean +/- SEM, P less than 0.001, 10 cases) and in advanced labor (2.53 times +/- 0.15, 10 cases, P less than 0.001) was highly significant. In the chorion-decidua the increase was 1.61 times +/- 0.09, P less than 0.001 in early labor and 1.66 times +/- 0.19, P less than 0.001 in advanced labor. Scatchard analysis showed a single receptor site for oxytocin in amnion and chorion decidua. The dissociation constant (Kd) did not change during the various stages of labor; the mean values found were 0.228 +/- 0.02 (mean +/- SEM) nM in the amnion and 0.193 +/- 0.03 nM in the chorion-decidua respectively. These findings suggest that human fetal membranes are target organs for oxytocin and that they might play a role in the onset of labor through an increase of receptor binding.

In vitro effects of beta-interferon on steroid receptors and prostaglandin output in human endometrial adenocarcinoma.

The effect of natural beta-interferon (beta-IFN) on steroid receptor levels and output of prostaglandins (PGs) was investigated in human endometrial cancer. beta-IFN determines in endometrial adenocarcinoma explants an increase of cytosolic estradiol (ER) and progesterone (PR) receptors at concentrations ranging from 10 to 1000 IU/ml of culture medium. Only cases in which there was an enhancement of at least 50% with respect to control values were considered. Low concentrations of beta-IFN (10 IU/ml of culture medium) produce an enhancement of ER in 60% and of PR in 42% of cases, while higher concentrations of beta-IFN (1000 IU/ml of culture medium) produce an enhancement of ER in 32%, and of PR in 82% of cases. Since PGs are involved in proliferation control in a large variety of tumors, we evaluated the ratio between PGF2-alpha and PGE2 levels in culture medium. This ratio increased, in our experimental model, after treatment with 10 and 1000 IU/ml of beta-IFN in 38% and 58% of cases respectively. Our data suggest that beta-IFN could affect cellular hormone sensitivity through a modification of ER and PR and it can also determine a variation of PG output in human endometrial cancer.