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The cytoplasmic estrogen receptor (ERc) and progesterone receptor (PRc) in mammary tumors have been recognized as useful biochemical markers for predicting the objective response of patients with advanced breast cancers to endocrine therapy. These proteins are also useful in the prognosis of gynecologic carcinoma. This report presents data showing the effect of sodium molybdate in the stabilization of estrogen and progesterone receptors. In rabbit uterine tissue, molybdate (20 mM) increased the binding of progesterone and estrogen to the receptors in several ways: (a) the apparent loss of detectable receptors during lengthy sucrose gradient analysis and at elevated temperature (30 degrees C) was reduced; (b) the instability of receptors due to storage at -70 degrees C was lessened, and (c) the conversion of the 7S PRc to the 3.5S form was minimized. Similarly, molybdate caused a qualitative and/or a statistically significant quantitative difference in receptor values for some human gynecologic tumors presented herein; the molybdate-associated changes vary with tumor specimen. Of the 8 tumors for which receptor values in the presence of molybdate (M+) and its absence (M-) can be compared, detectable ERc of 6 and PRc of 7 tumors increased with molybdate, and ERc of 2 and PRc of 1 tumor showed no change. In addition to the increase in receptor values, a concomitant shift of the 3-4S molecules to the 7-8S moieties was noted for some tumors (1 of 6 for ERc and 3 of 7 for PRc). In 2 receptor-poor tumor samples, ERc was only detected in M+ cytosols. These results show that molybdate is effective in reducing receptor degradation and stabilizes the 7-8S molecules from converting to 4S moieties. The addition of molybdate may be helpful for better quantitation of steroid receptors in clinical specimens.

The cytoplasmic content of estrogen and progesterone receptors (ERc and PRc) was measured in the rat uterine and mammary tissues during the period from late pregnancy through lactation. Uterine ERc and PRc, which sedimented at the 8S and 4S regions, respectively, of a 5-20% sucrose gradient, showed similar rise and decline patterns before and after parturition. Following a decline from the 15th day (114 +/- 13.7 fmol/mg protein) to the 20th day of pregnancy (57.7 +/- 10.2 fmol/mg protein), ERc levels increased almost 2.5-fold at the time of parturition. A decrease to the predelivery level by 24 h post-delivery was followed by a steady increase to 270.6 +/- 46 fmol/mg protein by 15 days of lactation. Uterine PRc levels also showed a peak similar to that of ERc at the time of parturition (24.3 +/- 1.1 fmol/mg protein). The level of ERc in mammary gland 6 h postpartum was the lowest (1.5 +/- 0.3 fmol/mg protein) and during the first 10 days of lactation ERc levels were maintained at about 10 fmol per mg of cytosol protein. Results herein suggest that levels of these steroid receptors may be hormonally regulated and that the uterus and mammary gland may have a different sensitivity to these regulatory control mechanisms. The physiological significance in the variation of these receptors in conjunction with the onset of parturition is discussed.

In order to study whether cytosolic progesterone receptor (PRc) is involved in progesterone-induced proliferative arrest of breast cancer cells (CAMA-1N), subunit composition of PRc in these cells was characterized. In the TSK G3000 high-performance liquid chromatography (HPLC) column, molybdate-stabilized PRc eluted as a single sharp peak immediately following the void volume. PRc from this peak had a sedimentation coefficient of 7.6 S and was eluted at 0.22 M salt from a linear gradient (0.1 to 0.4 M NaCl) in a DEAE column. When covalently labeled with [3H]R5020, analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and visualized by fluorography, PRc from crude cytosol exhibited two major protein bands with molecular weights of 105 +/- 2.1 and 83 +/- 3.2 kD, respectively. However, HPLC-purified PRc showed only one major band of 105 kD. These results show that PRc in CAMA-1N cells has steroid-binding components similar to other target tissues and provides a basis for further quantitative and qualitative analyses of PRc during cell proliferation and progesterone-induced growth arrest of CAMA cells.

In an attempt to differentiate between the biochemical characteristics of hormonal-dependent and independent gynecologic tumors, monoclonal antibodies (mABs) MBr1 and MBr3 were used to detect tumor antigens. Steroid receptors and MBr1 and MBr3 determinants were assayed independently in a double-blinded manner. Of the 45 gynecologic tumors analyzed, 16 of 20 (80%) with both progesterone receptors (PR) (greater than 10 fm/mg protein) and estrogen receptors (ER) (greater than 5 fm/mg protein) also contained high levels of MBr1 determinant. However, these receptors were not quantitatively related to MBr1 activity. The 15 of 17 (88%) tumors that contained receptors below the discriminant levels also had low or undetectable levels of MBr1 activity. In tumors where only either PR or ER was present, 2 of 2 PR+/ER- tumors and 2 of 6 PR-/ER+ tumors expressed MBr1 antigen. No relationship of MBr3 antigenic activity to the receptors was established. These results show that MBr1-recognized antigen is expressed largely in steroid receptor-positive tumors and these data suggest that either the antigen itself or its carrier protein may be regulated by estrogen. Like steroid receptors, MBr1 antigens may have important prognostic value in gynecologic tumors.

From 1977 to 1981, 39 cases of primary cervical carcinoma were assayed for the presence or absence of cytoplasmic estrogen (ERc) and progesterone (PRc) receptors by a saturation point dextran-coated charcoal assay. The levels of ERc and PRc were compared with clinical stage, histologic type, histologic grade, menstrual status, age, and survival. Carcinomas were divided into positive and negative receptor groups with the use of greater than 5 fmol/mg of cytosol protein for ERc and 10 fmol/mg of cytosol protein for PRc as discrimination points. Survival of the patients studied was computed by means of the product-limit analysis according to Kaplan-Meier. A statistically significant difference in survival in the PRc + group versus the PRc - group in the total group of patients was noted with the Mantel-Cox test (P = 0.049). When patients were stratified according to menopausal status, a statistically significant difference in survival was noted between the PRc + group versus the PRc - group in the premenopausal patients only.

Cytosolic progesterone receptors (PRcs) from the reproductive tract of the female turkey were analyzed by high-performance liquid chromatography using a diethylaminoethyl (DEAE) ion-exchange column. PRcs from oviduct tissue of laying, incubating, photorefractory and short-day turkey hens were compared. In general, three types of PRcs were identified: Receptor I, a partially displaceable species that was eluted at a 0.13 M salt concentration; and Receptors II and III, which were two specific binding species eluting at 0.23 M and 0.26 M, respectively. In the subdivided tissue from the laying hen oviduct, Receptor I was the major PRc species of the isthmus and Receptor III was the only receptor present in the uterus. The infundibulum and magnum each contained a small amount of Receptor II and a substantial amount of Receptor III. The whole oviduct of incubating hens contained a greater proportion of Receptor I than Receptor II or III, and these last two receptor types were present in equal quantity. The whole oviduct of the short-day hens had an equal distribution of the three receptor types. In the presence of sodium molybdate, an inhibitor of phosphatase and protease, only one sharp Receptor II species was seen in the magnum and uterus of the laying hen oviduct and in the whole oviducts of incubating and short-day hens. The transformation of Receptor II to Receptor III in the absence of sodium molybdate was facilitated by the aging of cytosol at 0-4 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Two sublines, CAMA-1R and CAMA-1N, were derived from the original CAMA-1 cells after continuous passages in our laboratory. 1R cells were supplemented in culture with estradiol and retained the properties of the original cell line, whereas 1N cells, not supplemented with estradiol, had a partial loss of estrogenic responsiveness. The doubling times for 1R and 1N cells were 2 and 2.4, respectively. These two sublines showed different effects on thymidine uptake after estradiol stimulation. Cells of 1R had a 2-fold greater thymidine incorporation than did the control without estradiol. In contrast, no difference of thymidine uptake was demonstrated in cells of 1N in the presence or absence of estradiol. Both cell lines contained cytoplasmic progesterone receptors with a Kd of 0.56 nM and a sedimentation coefficient of 6 to 7S on a 5 to 20% sucrose gradient. The progesterone receptor level in 1N was about 8-fold higher than in 1R cells. Both sublines exhibited a dose-dependent increase in progesterone receptor levels in response to estradiol with the maximal stimulation (8-fold increase) reached by using 5 nmol of estradiol. The rate of increase for estradiol-induced progesterone receptor appears to be the same for both sublines; a liner increase was demonstrated between Days 3 and 7 following plating. Our results show that estrogen regulation of thymidine uptake and progesterone receptor induction may be mediated through two separate mechanisms. Thus, following a chronically deficient supply of estradiol to 1N cells, there is apparent loss of responsiveness to estradiol-induced thymidine uptake, but the ability of these cells to respond to estradiol induction of progesterone receptor was retained.

Tissue levels of cytosolic estrogen receptors (ERc) and progesterone receptors (PRc) have been shown to have prognostic meaning in hormonally responsive cancers arising in the breast and endometrium. Although carcinomas of the uterine cervix rarely respond to hormonal manipulation, the normal cervical stroma and epithelia contain ERc and PRc. To study the prognostic value of these receptors, 65 cervical carcinomas for ERc and PRc were assayed before initiation of surgical or radiation therapy. In premenopausal women, logistic models demonstrated that clinical stage, surgical stage, and receptor level independently predict survival. If confirmed in further studies, ERc and PRc may prove to be useful prognostic factors in the management of cervical carcinomas.

Forty-two cases of recurrent and 14 cases of advanced clinical stage (III and IV) endometrial carcinoma are presented, in which progesterone and estrogen receptors from the metastatic sites were measured. Mean survival time (time from recurrence or, in advanced stages, from the time of diagnosis to death or last follow-up), mean total survival time (time from diagnosis to death or last follow-up), and mean time to recurrence (time from diagnosis of primary tumor to the time of recurrence) were positively correlated with positive progesterone and estrogen receptor status and with histologic grade of tumor. No correlation was found with age, clinical stage, depth of myometrial invasion, or site of metastasis. However, when multiple variables were considered with the Cox regression model, the combination most highly correlated with survival included progesterone receptor, grade of tumor, and site of metastasis (pelvis vs. other sites). All differences were statistically significant (p less than 0.05). We conclude that measurement of progesterone and estrogen receptors in metastatic or recurrent endometrial tumors may be used as an additional prognostic variable.

Eighty-six cases of primary endometrial carcinoma were assayed for the presence or absence of cytoplasmic estrogen and progesterone receptors by the saturation point dextran-coated charcoal assay. The levels of cytoplasmic progesterone receptors and estrogen receptors were analyzed according to clinical stage, histologic type and grade of the tumor, presence or absence of lymph node metastases, myometrial invasion, and survival. The cases were divided into positive and negative receptor groups with levels chosen of greater than 10 fmol/mg of cytosol protein for progesterone receptor and 5 fmol/mg of cytosol protein for estrogen receptor as discrimination points. Statistically significant survival differences were found between estrogen receptor positive versus estrogen receptor negative patients, progesterone receptor positive versus progesterone receptor negative patients, and estrogen positive-progesterone receptor positive versus estrogen negative-progesterone receptor negative patients. Mean cytoplasmic estrogen and progesterone receptor levels were inversely proportional to grade. This report suggests that treatment protocols should be devised to reflect the prognostic significance of receptor status.