Steroid Hormone Receptors In Tumors Research Articles

Immunological imbalance, gene polymorphism of biotransformation enzymes, and steroid hormone receptors in tumors in breast cancer patients

It is well known that results of breast cancer (BC) hormonal therapy depend on expression of tumor estradiol and progesterone receptors (ER and PR) in tumor tissue. Mechanisms of ER+/PR+ tumors conversion to ER+/PR- and ER-/PR- tumors remain scarcely studied. The decrease of steroid receptors expression seems to depend on action of genotoxic metabolites of environmental carcinogens (particularly, benzo[a]pyrene, BP) and endogenous steroids (in particular, estradiol, E2). The formation of these metabolites is regulated by the biotransformation enzymes. On the other hand, the formation of DNA-adducts with genotoxic metabolites may induce the synthesis of specific antibodies. Previously, it was shown that increase of the serum IgA-antibodies levels against Bp and E2 over the levels of IgA-antibodies against progesterone (IgA-Bp/IgA-Pg > 1 and IgA-E2/IgA-Pg), could be interpreted as immunological imbalance associated with high BC risk in healthy women. The purpose of this study was to detect the suggested associations between ER+/PR+ tumors conversion to ER+/PR+ and ER-/PR- tumors and immunological imbalance in the BC patients with distinct gene variants of biotransformation enzymes: CYP1A1*2A (rs 4646903), CYP1B1 (rs1056836), CYP19A1 (rs2470152), GSTT1 (del), GSTP1 (rs1695). The IgA-Bp, IgA-E2 and IgA-Pg were studied in 1321 non-smoking BC patients by non-competitive solid phase immunoassay. The conjugates of Bp, E2 and Pg with bovine serum albumin were adsorbed as target antibodies. The goat antibodies against human IgA conjugated with horseradish peroxidase were used for detection of the studied specific antibodies. Gene polymorphisms of biotransformation enzymes were analyzed by the real-time PCR. Tumor ER and PR were detected by the standard immunohistochemical methods.ER+/PR+ tumors in BC patients at the stage I (N = 534) were found in 68.7%, ER+/PR- in 15.6%, ER-/ PR- in 15.7%. In BC patients at the II-IV stage (N = 787), frequency of ER+/PR+ tumors decreased to 60.2%, ER+/PR- was similar (15.8%), and ER-/PR- increased to 24.0% (p < 0.0001). These alterations were revealed in BC patients at the IgA-Bp/IgA-Pg ratios > 1, and IgA-E2/IgA-Pg > 1 only. There were no differences found between BC patients at stage I and II-IV at the ER+/PR+, ER+/PR-, ER-/PR- frequencies when these ratios were low.The frequency of ER+/PR+ tumors in homozygotes TT of CYP19A1 was 77.1% at the I stage and 60.1% at the II-IV stages. Respectively the frequencies of ER-/PR- tumors were 11.8% and 26.1% (p < 0.001). ER+/ PR+ tumors were revealed in GSTT1 “+” BC patients at the I stage in 68.7% and at the II-IV stages in 58.0%. Respectively ER-/PR- tumors were found in 16.6% and 24.5% (p < 0.0004). The frequency of ER+/PR+ tumors was 57.1% in homozygotes GG of GSTP1 at the I stage and 60.7% at the II-IV stages. Respectively the frequencies of ER+/PR- were 14.3% and 22.2% and ER-/PR- were 28.6% and 19.0% (p < 0.001). Proportions of low and high IgA-Bp/IgA-Pg and IgA-E2/IgA-Pg ratios were the same at the any enzyme genotype of studied CYP or GST variants. In conclusion, we have revealed a sufficient contribution of immunological imbalance to the conversion of steroid receptors in breast cancer growth, being independent of several CYP and GST gene polymorphisms.

Abstract 4968: Importance of tumor microenvironment in the preclinical estrogen receptor positive breast cancer- Primary tumor and bone metastasis models

Abstract Estrogen receptor positive (ER+) breast cancer has ability to metastasize to bone in high frequency. Bone is known to be fertile soil for metastasized cancer cells to survive and in turn, metastasized tumor cells alter normally balanced bone environment. Prevention and treatment of bone metastasis is challenging and better understanding why bone metastasis are resistant to current therapies is needed. Aim of the present study was to explore the role of tumor microenvironment and estrogen supplementation on growth of primary breast cancer tumor and bone metastasis to establish predictive ER+ breast cancer models for drug development. ER+ human breast cancer MCF-7 cells were inoculated into mammary fat pad and in the tibia of female athymic nude mice. Mice received either hormonal supplementation (17-beta estradiol pellet, E2) or placebo. Tumor growth was followed for 5 and 9 weeks. From one group, E2 supplementation was removed on study week 5 and tumor growth was followed for 4 weeks. During the study, blood samples were collected for serum steroid concentration measurements and at the end, histopathological evaluation and immunohistochemical (IHC) stainings were performed to examine tumor steroid hormone receptor expression. Orthotopic MCF-7 tumor growth was clearly hormone dependent. E2 supplementation, that increased serum estradiol for app. 3-fold, supported tumor growth and when E2 was removed, tumor size decreased and no tumor growth was observed thereafter. In the full absence of E2 supplement, no orthotopic tumor growth was observed. In contrast, when MCF-7 cells were inoculated into tibia, tumor growth was observed both with and without E2 supplement. IHC stainings confirmed orthotopic tumor to express ER, PR and AR when animals received E2. After E2 removal, orthotopic tumors expressed still ER and AR but no longer PR. Also intratibial tumors expressed ER and PR in the presence of E2, but no PR in the absence of E2 supplement. E2 is needed to support MCF-7 tumor growth when cancer cells are inoculated orthotopically into mammary fat pad. No orthotopic tumor growth is observed in the absence of E2 supplement. In contrast, in the bone microenvironment, MCF-7 cells form tumor even in the absence of E2 supplement. Results highlight importance of tumor microenvironment in the breast cancer progression and also refer why tumor in the different sites may be resistant to therapy. Taking together, when developing new therapies against breast cancer, focus should be addressed not only on primary tumor growth but also on bone metastasis where cancer cells are under influence of bone environment. Citation Format: Jenni Bernoulli, Mari I. Suominen, Tiina Kähkönen, Jenni Mäki-Jouppila, Jussi M. Halleen, Riikka Oksala. Importance of tumor microenvironment in the preclinical estrogen receptor positive breast cancer- Primary tumor and bone metastasis models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4968. doi:10.1158/1538-7445.AM2017-4968

Influence of steroid hormones on the growth fraction of human breast carcinomas.

The growth fraction (GF) of human breast adenocarcinomas was studied in order to determine whether it was influenced by certain biologic characteristics of the host and whether it was modulated by the tumor's steroid hormone receptor status. It was also examined whether steroid treatment in vitro stimulated tumor's GF. Thirty-five primary breast adenocarcinomas from patients ranging in age from 26 to 85 years were analyzed for size and estrogen receptor (E2R) and progesterone receptor (PR) status. One portion of each tumor was cultured in medium 199 under four different conditions: addition of insulin alone or with 17 beta-estradiol (E), progesterone (P), or a combination of both hormones (E + P). In six cases, a dose-response curve was established for E (10(-14) to 10(-12) mol/L) and P (10(-11) to 10(-9) mol/L). Tissues were exposed to a continuous pulse of 2.5 microCi/mL (3H)-thymidine for five days before fixation and processing for autoradiography. GF ranged from 0.0074 to 0.3852, median 0.0550, and it was arbitrarily classified as low GF, less than 0.0550; or high GF, equal or greater than 0.0550. GF was significantly higher in patients with lymph nodes free of metastatic tumor than in those with positive lymph nodes. Estradiol treatment at low doses increased GF in 40% of tumors, whereas high doses increased GF in 14%. Progesterone treatment increased GF in 30% of tumors treated with low doses and in 14% of those treated with high doses. Treatment with E + P markedly depressed the GF of 85% of the tumors. It was concluded that the GF of breast carcinomas showed a great variability, which seemed to be independent of host factors such as age, menopausal status, parity history, or smoking habits; a second conclusion was that breast tumors' GF was not stimulated by steroid hormone treatment in vitro, and its response did not correlate with their hormone receptor status.

The steroid hormone receptors in tumors of adipose tissue.

The clinical evidence suggests that the steroid hormones may influence the biologic course of tumors of soft tissue. In an attempt to characterize the possible steroid hormone dependency of soft tissue, we studied the incidence and distribution of cytosolic receptors for the steroid hormones in benign and malignant tumors of adipose tissue origin. All specimens were assayed for the steroid hormone receptors by charcoal dextran technique and analyzed by the method of Scatchard. The results show a high incidence of cytosolic estrogen and glucocorticoid receptors in tumors of adipose tissue origin except in lipoma and well differentiated liposarcoma. The binding parameter of these receptors suggests that the receptors may be responsive to physiologic steroid hormonal milieu.