Tamoxifen, screening and new oestrogen receptor modulators

The impact of tamoxifen treatment on voice parameters in premenopausal women with breast cancer

OBJECTIVE

The study aims to investigate the estrogen-agonistic effects of tamoxifen on voice parameters in premenopausal women diagnosed with breast cancer.

METHODS

A total of 108 premenopausal women were included, segmented into distinct treatment groups and a control group. Objective sound analysis was conducted using robust statistical methods, employing SPSS 25.0 for data analysis.

RESULTS

The study identified a statistically significant reduction in Jitter values across all treatment groups compared to the control group. No significant changes were observed in other voice quality parameters such as F0, Shimmer, NHR, and HNR.

CONCLUSIONS

The findings suggest that tamoxifen may have an estrogen-agonistic effect on voice quality, thereby potentially influencing future treatment protocols. This research fills a critical void in existing literature and sets the stage for more comprehensive studies that consider affects of hormonal therapies to voice.

The value of anticancer drugs - a regulatory view

The high prices of new anticancer drugs and the marginal added benefit perceived by some stakeholders have fuelled a debate on the value of anticancer drugs in the European Union, even though an agreed definition of what constitutes a drug's value does not exist. In this Perspective, we discuss the value of drugs from different viewpoints and objectives of decision makers: for regulators, assessment of the benefit-risk balance of a drug is a cornerstone for approval; payers rely on cost-effectiveness analyses carried out by health technology assessment agencies for reimbursement decisions; for patients, treatment choices are based on personal preferences and attitudes to risk; and clinicians can use several scales (such as the ESMO Magnitude of Clinical Benefit Scale (ESMO-MCBS)) that have been developed as an attempt to measure value objectively. Although a unique definition that fully captures the concept of value is unlikely to emerge, herein we discuss the importance of understanding different perspectives, and how regulators can help to inform different decision makers.

A One-pot Multicomponent ‘Click’ Approach to the Synthesis of Novel Tamoxifen-triazole Conjugates using Nano Iron Oxide Catalyst and their Preliminary Antiproliferative Activity Studies

Background:

In an effort to establish new drug candidates with improved antiproliferative activity, we report here a novel class of compounds designed rationally by the replacement of an ethyl group in tamoxifen with a methylene (1H-1,2,4-triazole) and the introduction of 1,4- substituted 1,2,3-triazoles in the basic side chain.

Methods:

Magnetically separable iron oxide nanoparticles have been found to effectively catalyze the one-pot multicomponent click synthesis of 1,4-disubstituted 1,2,3-triazole conjugates in water. IR, 1HNMR, 13CNMR and HRMS experiments have been implemented for the unmistakable determination of the regiochemistry of the process. The novel compounds were evaluated for their antiproliferative activity against four human tumor cell lines, namely, MCF-7, MDA-MB-231, HeLa, and A549. Cell growth inhibition was assessed according to the standard Sulforhodamine B (SRB) cell proliferation method.

Results:

The most active compounds 4h, 4n and 5a have been identified with superior GI50 values in the range of 0.13–0.31 µM as compared with the reference drug, tamoxifen (0.25-0.72 µM).

Conclusion:

Additionally, taking the stereochemistry into consideration, E isomers seem slightly more active towards the tested cancer cell lines with respect to Z isomers.

Post-menopausal bleeding - Is transvaginal ultrasound a useful first-line investigation in tamoxifen users?

Objective To evaluate the role of transvaginal ultrasound triage in women with a history of tamoxifen treatment who present with post-menopausal bleeding. Study design A retrospective review was undertaken of patients who presented with symptoms of post-menopausal bleeding and underwent ultrasound triage. Endometrial thickness and ultrasonographic features were then correlated with hysteroscopic and histopathological outcome data. The findings and outcomes for women with a history of tamoxifen use (tamoxifen group) were compared to those who had not taken tamoxifen (non-tamoxifen group). Results A total of 614 women with post-menopausal bleeding underwent transvaginal ultrasound triage, of whom 53 had a history of current or previous tamoxifen treatment. An endometrial thickness of ≥5 mm or the presence of other abnormal features was used to triage women to further investigation by hysteroscopy and biopsy. Endometrial thickness was significantly greater in the tamoxifen group (11 mm vs. 6 mm). Nearly all of the tamoxifen group were triaged to further investigation (98.1%), compared with significantly fewer in the non-tamoxifen group (68.3%) Overall, the incidence of endometrial pathology was also significantly higher in tamoxifen patients (43.4% vs. 31.7%). Conclusion For women presenting with post-menopausal bleeding, the use of transvaginal ultrasound as a triage tool is rarely helpful in evaluating women who have a history as tamoxifen use, as most will require further investigation with hysteroscopy and biopsy. A post-menopausal bleeding protocol that omits transvaginal ultrasound for women with a history of tamoxifen use may be an appropriate and effective pathway for managing these patients.

[The contribution of ultrasonography in the exploration of postmenopausal metrorrhagias]

Post-menopausal metrorrhagias represent a frequent reason for consultation in gynecology. Our study aims to evaluate the contribution of pelvic ultrasonography in the exploration of endocavitary lesions in people experiencing this symptom and to compare the results found with those of hysteroscopy and histology. This was an analytic retrospective study of 33 cases referred for evaluation of postmenopausal metrorrhagias at the department of gynecology and obstetrics «A» in the Center of Maternity and Neonatology of Tunis in 2012. All patients underwent pelvic ultrasonography and diagnostic hysteroscopy. We analyzed and compare the data obtained with pelvic ultrasonography, hysteroscopy and histological examination. The average age of our patients was 57.78 years and the average age of menopause was 48.36 years. The confrontation between ultrasonographic and histological data showed that ultrasonography has a sensitivity of 80.6%, a specificity of 79.38%, positive predictive value (PPV) of 67.03% and negative predictive value (NPV) of 91.54%. With respect to hysteroscopy these values were 84,44%, 82,72%, 69,93% and 92,65% respectively. Performance level for each exploratory diagnostic tool varied according to the lesion which caused metrorrhagias and generally hysteroscopy was more reliable in the exploration of metrorrhagias than ultrasonography: Youden index 0.67 against 0.59. Our results confirmed data published in the literature that assigns to hysteroscopy a greater reliability compared to pelvic ultrasonography in the diagnosis of endocavitary lesions causing postmenopausal metrorrhagias.

Tamoxifen in breast cancer ipse dixit in uterine malignant mixed Müllerian tumor and sarcoma-A report of 8 cases and review of the literature

AIM

Report the outcome of 8 patients (pts) with breast cancer (BC) treated with Tamoxifen (TAM) that developed malignant mixed Müllerian tumor (MMMT) and rare uterine sarcoma (RUS).

PATIENTS AND METHODS

Retrospective study based on data collected from the department medical records between April 1999 and September 2010 among 583 pts with endometrial cancer, 36 pts with MMMT and RUS histopathology. Among them, 8 pts underwent TAM between 4 and 10 years due to a previous diagnosis of BC; all pts were post-menopausal with regular gynecological surveillance; 6 pts (75%) with abnormal uterine bleeding. The diagnosis of 6 pts (MMMT) and 2 pts (RUS) occurred at median interval of 8 years (range 4-12) after initial BC treatment. Pts underwent surgical treatment and were staged as stage I (3pts), IIIA (3pts) and IIIC (2 pts) (FIGO 1988); followed by whole pelvis irradiation (50 Gy) and intracavitary HDR brachytherapy boost (24 Gy). Two pts underwent chemotherapy (CT). Overall and disease free survival was calculated by Kaplan Meier method.

RESULTS

With a median follow-up of 47 months (range 17-130), 3 pts remain alive recurrence-free of BC and RUS. Four pts died with distant metastasis within the first follow-up year, without BC. One pt died from non-related cancer cause. No evidence of local recurrence was found in the whole group of pts. At two years, DFS and OS were 40% and 80%, respectively.

CONCLUSION

As reported in the literature, TAM administration and causal effect on MMMT and RUS in BC pts is still unknown. No reports about outcome from these specific pts were found.

Screening for uterine tumours

The most prevalent uterine tumours are leiomyomas, which are benign and have a prevalence of about 50% at menopause. The incidence of endometrial cancer and uterine sarcomas is about 25 per 100,000 and 0.7 per 100,000, respectively. Reported risk factors for endometrial cancer are advanced age, unopposed oestrogen stimulation, late menopause, obesity, diabetes mellitus, nulliparity, feminising ovarian tumours, polycystic ovarian syndrome, tamoxifen and belonging to a hereditary non-polyposis colorectal cancer family. Unopposed oestrogen stimulation and tamoxifen have also been confirmed to induce uterine sarcomas. Cervical cytology, endometrial sampling and ultrasound have been proposed in the early diagnosis of endometrial cancer. No pathognomonic ultrasound, magnetic resonance imaging or computed tomography features are able to differentiate between a leiomyoma and a uterine sarcoma, and reliable serum markers for sarcomas are lacking. To date, mass screening for uterine malignancies is not feasible or effective.

A mass spectrometric approach for the study of the metabolism of clomiphene, tamoxifen and toremifene by liquid chromatography time-of-flight spectroscopy

In this paper, we discuss the capabilities of liquid chromatography coupled to mass spectrometry with a time-of flight system with accurate mass measurement for the detection and characterisation of drug metabolites in biological samples for anti-doping purpose. Urinary excretion samples of three selective oestrogen receptor modulators (SERMs) with a common triphenylethylene structure: clomiphene, toremifene, and tamoxifen, obtained after oral administration of a single dose of each drug, were analysed using a time-of-flight system, after automatic tuning and calibration of the equipment, in positive full scan mode using an electrospray ionisation source. Following this approach we detected most of all significant metabolites reported by others and postulated new metabolites, especially for toremifene, have been characterised: N-demethyl-3-hydroxy-4-methoxy-toremifene and 3- hydroxy-4-methoxy-toremifene; in addtiona to this, in the urinary excretion samples of toremifene some metabolites, without the characteristic chlorine isotope pattern, discarded in previous studies, that are also metabolites of tamoxifen, were identified. The lack of certified reference materials does not allow an accurate determination of the limit of detection (LODs) of all metabolites; however an estimation taking into account the response factor of similar compounds allows to estimate that all metabolites are clearly detectable in a range of concentration comprised between 10 ng mL(-1) and 30 ng mL(-1).

Effect of estrogens on skin aging and the potential role of SERMs

In humans, structural and functional changes attributable to aging are more visibly evident in the skin than in any other organ. Estrogens have significant effects on skin physiology and modulate epidermal keratinocytes, dermal fibroblasts and melanocytes, in addition to skin appendages including the hair follicle and the sebaceous gland. Importantly, skin aging can be significantly delayed by the administration of estrogen. This paper reviews the effects of estrogens on skin and the mechanisms by which estrogens can alleviate the changes due to aging that occur in human skin. The relevance of estrogen replacement therapy (HRT) in postmenopausal women and the potential value of selective estrogen receptor modulators (SERMs) as a therapy for diminishing skin aging are also highlighted.

Trilostane in advanced breast cancer

Antiestrogens, principally tamoxifen, and aromatase inhibitors have been used as the first- and second-line therapy in patients with advanced postmenopausal breast cancer for many years. However, some patients acquire resistance to these treatments and, at present, further endocrine treatment is achieved by merely substituting the current medication with a different antiestrogen or aromatase inhibitor. Trilostane offers an alternative endocrine treatment due to its unique mode of action. It is an allosteric modulator of the estrogen receptor and targets both the estrogen- and growth factor-dependent pathways through which estradiol stimulates cell proliferation. In clinical trials, trilostane has been shown to be an effective treatment for breast cancer in patients who have relapsed after receiving treatment with one or more forms of endocrine therapy. Ongoing and future clinical trials are examining the potential for the use of trilostane in premenopausal breast cancer, as well as in other malignancies such as prostate cancer.

Gene expression changes induced by estrogen and selective estrogen receptor modulators in primary-cultured human endometrial cells: signals that distinguish the human carcinogen tamoxifen

Tamoxifen has long been the endocrine treatment of choice for women with breast cancer and is now employed for prophylactic use in women at high risk from breast cancer. Other selective estrogen receptor modulators (SERMs), such as raloxifene, mimic some of tamoxifen's beneficial effects and, like tamoxifen, exhibit a complex mixture of organ-specific estrogen agonist and antagonistic properties. However, accompanying the positive effects of tamoxifen has been the emergence of evidence for an increased risk of endometrial cancer associated with its use. A more complete understanding of the mechanism(s) of SERM carcinogenicity and endometrial effects is therefore required. We have sought to compare and characterise the transcript profile of tamoxifen, raloxifene and the agonist estradiol in human endometrial cells. Using primary cultures of human endometria, to best emulate the in vivo responses in a manageable in vitro system, we have shown 230 significant changes in gene expression for epithelial cultures and 83 in stromal cultures, either specific to 17beta-estradiol, tamoxifen or raloxifene, or changed across more than one of the treatments. Considering the transcriptome as a whole, the endometrial responses to raloxifene or tamoxifen were more similar than either drug was to 17beta-estradiol. Treatment of endometrial cultures with tamoxifen resulted in the largest number of gene changes relative to control cultures and a high proportion of genes associated with regulation of gene transcription, cell-cycle control and signal transduction. Tamoxifen-specific changes that might point towards mechanisms for its proliferative response in the endometrium included changes in retinoblastoma and c-myc binding proteins, the APCL, dihydrofolate reductase (DHFR) and E2F1 genes and other transcription factors. Tamoxifen was also found to give rise to the highest number of gene expression changes common to those that characterise malignant endometria. It is anticipated that this study will provide leads for further and more focused investigation into SERM carcinogenicity.

Regulating the Tumor Suppressor Gene Maspin in Breast Cancer Cells

PURPOSE

Mammary epithelial cells and the majority of breast cancer tumors require estrogen for continued growth. Antiestrogen therapy alone, or in combination with other drugs, has long been a common procedure for breast cancer treatment and prophylaxis. Thus, there is a critical need to elucidate the mechanism(s) of action of antiestrogen treatment, especially for patients who are at risk of breast cancer development or who are currently receiving hormone therapy. In this study, we examined the ability of hormones to regulate the expression of a tumor suppressor gene, maspin, which is a serine protease inhibitor (serpin) that plays an important role in mammary gland development and is silenced during breast cancer progression. Specifically, our hypothesis tested the clinical efficacy of tamoxifen to regulate maspin expression.

EXPERIMENTAL DESIGN

We used maspin promoter luciferase reporter plasmids that were transfected into normal human mammary epithelial (HMEC1331) and MCF-7 breast cancer cells, followed by determination of the effect of hormones and their antagonists on maspin promoter activity. At the protein level, cytosolic fractions from both cell types before and after hormone treatment were subjected to Western blot analysis to determine maspin level.

RESULTS AND CONCLUSIONS

Our studies revealed that the antiestrogen tamoxifen induces maspin promoter activity. Interestingly, antiandrogen flutamide could also induce maspin in both cell lines tested. These observations were further confirmed in patient tissues. These novel findings provide a new mechanism of action for tamoxifen under normal and pathological conditions. More significantly, these findings could have a potential impact on future therapeutic intervention strategies for breast cancer.

Ligand-Induced Regulation of ERα and ERβ is Indicative of Human Breast Cancer Cell Proliferation

Two estrogen receptors (ER), ERalpha and ERbeta, are expressed in breast cancer but their role in treatment response is unclear. The overall objective of this study was to determine if the presence of ERbeta protein in breast cancer cell lines is an indicator of a poor prognosis based on cell proliferation. In addition, we determined the effect of estradiol (E2) and selective estrogen receptor modulators (SERMs), such as tamoxifen and genistein, on ERalpha and ERbeta protein regulation, to help in the understanding of the mechanism behind their role in modulating cell proliferation. Using western blot and immunofluorescence analysis, the ER positive cell lines, MCF-7 and T47D, were found to contain both ERalpha and ERbeta, and thus were used as model systems. E2 and genistein, which increased cell proliferation in both cell lines, induced an up regulation of ERbeta in both cell lines. This suggests that an estrogenic response in breast cancer cells is indicated by an increase in ERbeta expression. Tamoxifen decreased cell proliferation in both cell lines, while up regulating ERalpha in both cell lines, suggesting that antiestrogenic response is indicated by an increase in ERalpha expression. Although a change in the ERalpha/ERbeta ratio may play a role in the effect seen in cell proliferation, this study indicates that ERbeta is a poor prognosticator of cell proliferation in breast cancer and that ERalpha is a positive prognosticator of responsiveness to antiestrogen treatment.

Pre-validation study for OECD enhanced test guideline 407 protocol by gavage for 4 weeks using propylthiouracil and tamoxifen

To develop and pre-validate an enhanced protocol for OECD Test Guideline 407, we performed a 28-day repeated-dose toxicity study using the administration of propylthiouracil (PTU) and tamoxifen (TAM) in Sprague-Dawley (SD) rats. Six male and female SD rats were treated orally with PTU in corn oil at the dose of 0, 0.1, 1, or 10 mg/kg per day and TAM at dose of 0, 5, 30 or 200 microg/kg per day for 4 weeks. In the study using PTU, the body weights were reduced from the third week of the study in 10 mg/kg per day group. In clinical biochemistry, the levels of 3,5,3'-triiodothyronine (T3) and thyroxine (T4, 3,5,3',5'-tetraiodothyrosine) were also significantly decreased in 10 mg/kg per day group. Also, thyroid glands in 10 mg/kg per day group were bigger than those in the control group. In the histopathological examination, diffuse hyperplasia and hypertrophy of thyroid follicular cells were observed in all treatment groups, leading to the reduction of lumen size and papillary enfolding of lining epithelium. In the study using TAM, the body weights were reduced from the first week of the study in 200 microg/kg per day group. Relative testes and epididymes weights were increased and relative right ovary and uterus weights were reduced in 200 microg/kg per day group. Also, in the histopathological finding severe endometrial squamous metaplasia and endometrial gland atrophy and severe follicular cystic change were observed in TAM 200 microg/kg per day-treated group. On the basis of the results, the thyroid hormone levels, gross findings, and histopathological findings may be useful parameters for the detection of the endocrine-related effect of PTU and also reproductive organ weight and histopathological findings may be good parameters to detect the effect of TAM. Therefore, it is concluded that enhanced OECD TG407 might be useful for screening and detecting endocrine disrupters.

Induction of apoptosis in estrogen dependent and independent breast cancer cells by the marine terpenoid dehydrothyrsiferol

Breast cancer (BCA) represents the highest incidence of death in 35- to 60-year-old women. Above all, hormone unresponsive BCA is still associated with poorer prognosis than hormone receptor expressing malign, mammary tumors. There is a consistent need for effective compounds to treat especially the first variant of this disease. Therefore, we investigated the cytotoxic effects of the marine polyether triterpenoid dehydrothyrsiferol (DT) in four BCA cell lines. Annexin V labeling revealed higher rates of DT-induced apoptosis in hormone insensitive than in estrogen receptor expressing cells. Flow cytometric analysis of combined DNA fragmentation and total DNA labeling allowed us to ascribe apoptotic cells to their cell cycle stage. Although, high cell mortality was detected in mitogen dependent G(1)-phase, time, concentration, and cell line dependent populations of apoptotic cells were also found to be of S-phase and G(2)/M-phase origin. These results suggest that the induction of apoptosis by DT might be transduced through more than one effector pathway. Cell cycle distributions and 5-bromo-2'-deoxyuridine incorporation varied in a treatment dependent manner and differed from control experiments with colchicine and doxorubicin which exclude that DT functions as a mitosis inhibitor. In summary, we propose that DT might be an interesting candidate for an antitumor drug development regimen.

Non-competitive steroid inhibition of oestrogen receptor functions

Currently available antioestrogens, such as tamoxifen, are competitive inhibitors that bind to the ligand binding sites of oestrogen receptors, ERalpha and ERbeta. The search for alternative anti-hormone therapies is prompted by the need for drugs that are effective when tumours become tamoxifen resistant. The existence of different receptor isoforms also raise the possibility of improving selectivity. Earlier use of the 3beta-hydroxysteroid dehydrogenase inhibitor, trilostane (4alpha,5- epoxy-17beta-hydroxy-3-oxo-5alpha-androstane-2alpha-carbonitrile), suggested that it had beneficial actions in breast cancer that were only partially attributable to inhibition of steroidogenesis. The present studies on the interactions of trilostane with oestrogen receptors show that it (i) inhibits oestrogen-stimulated proliferation in MCF-7 breast cancer cells, (ii) enhances the affinity of oestradiol binding to ER in rat uteri and specifically increases oestradiol binding to an ERbeta-like isoform, (iii) inhibits ERalpha and ERbeta binding to the classical vitellogenin gene oestrogen response element (ERE) and (iv) inhibits oestrogen-stimulated gene transcription in ERE-linked reporter systems in MCF-7 cells. The results demonstrate a novel, presumably allosteric, mode of antioestrogen action. The beneficial actions of trilostane in breast cancer may be attributed to the combination of this antioestrogen effect with its well documented suppression of steroidogenesis.

Synthesis, structural evaluation, and estrogen receptor interaction of 2,3-diarylpiperazines

To develop novel estrogen receptor (ER) ligands, ring-fused derivatives of the hormonally active (1R,2S)/(1S,2R)-1-(2-chloro-4-hydroxyphenyl)-2-(2,6-dichloro-4-hydroxyphenyl)ethylenediamine 4b were synthesized. (2R,3S)/(2S,3R)-2-(2-Chloro-4-hydroxyphenyl)-3-(2,6-dichloro-4-hydroxyphenyl)piperazine 4 induced ligand-dependent gene expression in MCF-7-2a cells, stably transfected with the plasmid ERE(wtc)luc and was therefore used as a lead structure. The influence of the substitution pattern in the aromatic rings (4-OH (1), 2-F,4-OH (2), 2-Cl,4-OH (3), 2,6-Cl2,3-OH (5), and 2,6-Cl2,4-OH (6)) and the effect of N-ethyl chains on the ER binding and activation of gene expression were studied. The synthesis started from the respective methoxy-substituted (1R,2S)/(1S,2R)-configurated 1,2-diarylethylenediamines 6b to 4b, which were reacted with dimethyl oxalate in order to get 5,6-diarylpiperazine-2,3-diones. Reduction with BH3*tetrahydrofuran and ether cleavage with BBr3 yielded the piperazines 1-6. The N-alkylation of the piperazines 1a-3a, which was employed for obtaining compounds 7-11, was succeeded by acetic anhydride followed by reduction and ether cleavage. Nuclear magnetic resonance (NMR) spectroscopical studies revealed a synclinal conformation of the 1,2-diarylethane pharmacophore and a preference of the substituents at the heterocyclic ring for an equatorial position. This spatial structure prevents an interaction with the ER analogously to that of estradiol (E2). Therefore, the piperazines can displace E2 from its binding site only to a very small extent. Only the N-ethyl (8) and N,N'-diethyl (11) derivatives of piperazine 3 showed relative binding affinity values > 0.1% (8, 0.42%, and 11, 0.17%). Nevertheless, ER-mediated gene activation was verified for the piperazines 4 (20%), 6 (73%), 7 (34%), 8 (74%), and 11 (37%) (concentration, 1 microM; E2, 100% activation) on the MCF-7-2a cell line. O-methylation led to completely inactive compounds and showed the necessity of H bridges from the piperazines to the ER for activating gene expression.