Differential Effects Of Tamoxifen Research Articles

Abstract PS5-09: Tumour infiltrating lymphocytes of prognostic value in different molecular breast cancer subgroups and as a suggestive predictive factor for adjuvant tamoxifen benefit in premenopausal patients after 30 years follow-up

Abstract BACKGROUND The molecular breast cancer subgroups comprise diverse immune biology; for human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC) and triple-negative breast cancer (TNBC) abundance of tumour infiltrating lymphocytes (TILs) have been shown to indicate good prognosis and could predict pathological complete response after neoadjuvant chemotherapy. In contrast, the clinical relevance of TILs in estrogen receptor-positive/HER2-negative (ER+/HER2-) tumours is not settled. We primary aimed to analyse the prognostic effect of TILs on BC-free interval (BCFi) in premenopausal patients, stratified by molecular subgroups. The secondary aim was to investigate the predictive value of TILs on tamoxifen benefit. METHODS Archival tissue from primary tumours was collected from patients included in the SBII:2pre trial. In this study, 564 premenopausal women were randomised between two years of adjuvant tamoxifen or no systemic treatment regardless of hormone-receptor status. TILs were scored on whole tissue sections and the tumours were divided into ER+/HER2- (n = 255), HER2+ (n = 65) and TNBC (n = 95) molecular subgroups by immunohistochemistry and in situ hybridisation (ISH). The prognostic value of TILs was evaluated in patients allocated to no systemic therapy, whose tumours were successfully scored for TILs and had IHC/ISH data for generating molecular subgroups (n = 221). All patients with ER+ tumours and successfully annotated TILs were considered for prediction of tamoxifen benefit (n = 321). The median follow-up was 28 years and the prognostic and predictive analyses were performed by cumulative incidence curves and Cox regression analyses. RESULTS TILs were successfully scored in 477 tumours with available ER status and the proportion of low (<10%), intermediate (10-49%) and high (≥50%) TILs were 52% (n = 248), 33% (n = 157) and 15% (n = 72), respectively. High infiltration of TILs was a favourable prognostic factor (univariable analysis: hazard ratioBCFi (HRBCFi) 0.40; 95% confidence interval (CI) 0.22-0.71; P = 0.002) (Table 1). The results were essentially the same in the ER+/HER2- molecular subgroup (HRBCFi 0.40; 95% CI 0.14-1.09; P = 0.07). Adjuvant tamoxifen improved prognosis in patients with ER+ tumours and TILs levels <50%, (univariable analysis HRBCFi 0.63; 95% CI 0.47-0.84; P = 0.002), which was not observed in patients displaying high immune infiltration (≥50%) (HRBCFi 0.84; 95% CI (0.24-2.86); P = 0.77). However, evidence for differential effect of tamoxifen in categories of TILs, i.e. interaction, was weak. CONCLUSIONS We demonstrate a long-term favorable prognostic value of levels of TILs in a cohort of premenopausal BC patients. This effect seems to be extended to the ER+/HER2- subgroup. A beneficial effect of tamoxifen in ER+ patients was observed in patients with tumours of low TILs infiltration as compared to patients with tumours of high immune infiltration, but we could not confirm a treatment predictive effect. Table 1. Uni- and multivariable Cox regression analyses of BCFi and OS (control arm)Univariable*MultivariableEndpointBCFiOSBCFiOSHR (95% CI); P valueTILs, category***All molecular subgroups(n = 221)(n = 213)Low (Ref.)1.001.001.001.00Intermediate1.10 (0.78-1.54); 0.611.26 (0.88-1.80); 0.210.61 (0.40-0.93); 0.020.65 (0.41-1.02); 0.06High0.40 (0.22-0.71); 0.0020.52 (0.29-0.95); 0.030.22 (0.11-0.43); <0.0010.23 (0.11-0.48); <0.001ER+/HER2-(n = 136)(n = 135)Low (Ref.)1.001.001.001.00Intermediate1.02 (0.63-1.64); 0.941.02 (0.61-1.71); 0.950.69 (0.42-1.15); 0.160.65 (0.37-1.15); 0.14High0.40 (0.14-1.09); 0.070.55 (0.20-1.52); 0.250.20 (0.06-0.60); 0.0040.30 (0.10-0.96); 0.04HER2+(n = 38)(n = 35)Low (Ref.)1.001.001.001.00Intermediate1.47 (0.62-3.49); 0.391.07 (0.45-2.56); 0.880.47 (0.14-1.60); 0.230.38 (0.11-1.31); 0.13High0.28 (0.08-0.97); 0.050.27 (0.08-0.96); 0.040.06 (0.01-0.56); 0.010.05 (0.01-0.39); 0.005TNBC(n = 47)(n = 43)Low (Ref.)1.001.001.001.00Intermediate0.76 (0.31-1.87); 0.551.24 (0.49-3.14); 0.650.59 (0.21-1.67); 0.321.02 (0.34-3.11); 0.97High0.27 (0.08-0.88); 0.030.44 (0.14-1.36); 0.160.38 (0.11-1.39); 0.150.59 (0.16-2.26); 0.44*Stratified by Region**The following variables were included in multivariable analysis: age (≥40 vs.<40 years), nodal status (0 vs.1-3 vs. ≥4), tumour size (>20 mm vs. ≤20), NHG (1 vs. 2 vs. 3), ER (positive vs. negative), PR (positive vs. negative), HER2 (positive vs. negative), LVI (present vs. absent) and TILs (high vs. intermediate vs. low). Stratified by Region.*** TILs were categorised as low: <10%, intermediate: 10-49% and high: ≥50%Abbreviations: BCFi breast cancer free-interval, OS overall survival, TILs tumour infiltrating lymphocytes, HER2 human epidermal growth factor receptor 2, TNBC triple-negative breast cancer, NHG nottingham histological grade, ER estrogen receptor, PR progesterone receptor, HR hazard ratio, CI confidence interval Citation Format: Christine Lundgren, Pär-Ola Bendahl, Maria Ekholm, Mårten Fernö, Carina Forsare, Ute Krüger, Bo Nordenskjöld, Olle Stål, Lisa Rydén. Tumour infiltrating lymphocytes of prognostic value in different molecular breast cancer subgroups and as a suggestive predictive factor for adjuvant tamoxifen benefit in premenopausal patients after 30 years follow-up [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-09.

Estrogen receptor antagonism uncovers gender-dimorphic suppression of whole body fat oxidation in humans: differential effects of tamoxifen on the GH and gonadal axes.

Tamoxifen, a selective estrogen receptor modulator, suppresses GH secretion in women but not in men. It increases testosterone levels in men. As GH and testosterone stimulate fat metabolism, the metabolic consequences of tamoxifen may be greater in women than in men. To determine whether tamoxifen suppresses fat oxidation (Fox) to a greater degree in women than in men. An open-label study of ten healthy postmenopausal women and ten healthy men receiving 2-week treatment with tamoxifen (20 mg/day). GH response to arginine stimulation, serum levels of IGF1, testosterone and LH (men only), sex hormone binding globulin (SHBG) and whole body basal and postprandial Fox. In women, tamoxifen significantly reduced the mean GH response to arginine stimulation (Δ -87%, P<0.05) and circulating IGF1 levels (Δ -23.5±5.4%, P<0.01). Tamoxifen reduced postprandial Fox in women (Δ -34.6±10.3%; P<0.05). In men, tamoxifen did not affect the GH response to arginine stimulation but significantly reduced mean IGF1 levels (Δ -24.8±6.1%, P<0.01). Tamoxifen increased mean testosterone levels (Δ 52±14.2%; P<0.01). Fox was not significantly affected by tamoxifen in men. Tamoxifen attenuated the GH response to stimulation and reduced postprandial Fox in women but not in men. We conclude that at a therapeutic dose, the suppressive effect of tamoxifen on fat metabolism is gender-dependent. Higher testosterone levels may mitigate the suppression of GH secretion and Fox during tamoxifen treatment in men.

Direct, Differential Effects of Tamoxifen, 4-Hydroxytamoxifen, and Raloxifene on Cardiac Myocyte Contractility and Calcium Handling

Tamoxifen (Tam), a selective estrogen receptor modulator, is in wide clinical use for the treatment and prevention of breast cancer. High Tam doses have been used for treatment of gliomas and cancers with multiple drug resistance, but long QT Syndrome is a side effect. Tam is also used experimentally in mice for inducible gene knockout in numerous tissues, including heart; however, the potential direct effects of Tam on cardiac myocyte mechanical function are not known. The goal of this study was to determine the direct, acute effects of Tam, its active metabolite 4-hydroxytamoxifen (4OHT), and related drug raloxifene (Ral) on isolated rat cardiac myocyte mechanical function and calcium handling. Tam decreased contraction amplitude, slowed relaxation, and decreased Ca2+ transient amplitude. Effects were primarily observed at 5 and 10 μM Tam, which is relevant for high dose Tam treatment in cancer patients as well as Tam-mediated gene excision in mice. Myocytes treated with 4OHT responded similarly to Tam-treated cells with regard to both contractility and calcium handling, suggesting an estrogen-receptor independent mechanism is responsible for the effects. In contrast, Ral increased contraction and Ca2+ transient amplitudes. At 10 μM, all drugs had a time-dependent effect to abolish cellular contraction. In conclusion, Tam, 4OHT, and Ral adversely and differentially alter cardiac myocyte contractility and Ca2+ handling. These findings have important implications for understanding the Tam-induced cardiomyopathy in gene excision studies and may be important for understanding effects on cardiac performance in patients undergoing high-dose Tam therapy.

Tamoxifen inhibits transforming growth factor-α gene expression in human breast carcinoma samples treated with triiodothyronine

To examine the effects of triiodothyronine (T3), 17beta-estradiol (E2), and tamoxifen (TAM) on transforming growth factor (TGF)-alpha gene expression in primary breast cancer cell cultures and interactions between the different treatments. Patients included in the study (no.=12) had been newly diagnosed with breast cancer. Fresh human breast carcinoma tissue was cut into 0.3- mm slices. These slices were placed in six 35-mm dishes on 2-ml organ culture medium. Dishes received the following treatments: dish 1: ethanol; dish 2: T3; dish 3: T3+TAM; dish 4: TAM; dish 5: E2; dish 6: E2+TAM. TGF-alpha mRNA content was normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA levels. All tissues included in this study were positive for estrogen receptor (ER) and thyroid hormone receptor expression. Treatment with T3 for 48 h significantly increased TGF-alpha mRNA levels compared to controls (15-fold), and concomitant treatment with TAM reduced expression to 3.4-fold compared to controls. When only TAM was added to the culture medium, TGF-alpha mRNA expression increased 5.3-fold, significantly higher than with all other treatment modalities. We demonstrate that TGF-alpha mRNA expression is more efficiently upregulated by T3 than E2. Concomitant treatment with TAM had a mitigating effect on the T3 effect, while E2 induced TGF-alpha upregulation. Our findings show some similarities between primary culture and breast cancer cell lines, but also some important differences: a) induction of TGF-alpha, a mitogenic protein, by TAM; b) a differential effect of TAM that may depend on relative expression of ER alpha and beta; and c) supraphysiological doses of T3 may induce mitogenic signals in breast cancer tissue under conditions of low circulating E2.

Differential effects of tamoxifen and anastrozole on optic cup size in breast cancer survivors

IntroductionThe main purpose of this study was to determine whether the optic cups of tamoxifen users and anastrozole users differ in size, with the cups of the tamoxifen users being smaller.MethodsOptic nerve head (ONH) topography was measured using a commercially available, confocal scanning laser ophthalmoscope for three populations of amenorrheic women ages 40–69 years: subjects using (1) tamoxifen (20 mg/day) or (2) anastrozole (1 mg/day) for ≤ 2 years as adjuvant therapy after successful primary treatment for breast cancer, and (3) control subjects with no breast cancer histories and not using any hormonal medication. All subjects had excellent visual acuity and healthy eyes, based on conventional photographic assessment.ResultsThe cup volumes of the tamoxifen users were shown to be significantly smaller than the cup volumes of the anastrozole users, which were indistinguishable from normal. Because the cup volumes of the tamoxifen users decreased markedly with age at about 50 years and because anastrozole is indicated only for post-menopausal women, comparisons were reassessed for subjects older than 50 years. For these subjects, the cup volumes of the tamoxifen users averaged less than half of the volumes for each of the other two subject groups, and significant between-group differences existed in both the lateral (cup area) and axial (cup depth) directions. In contrast, any between-group differences at the ONH margin were small and not significant.ConclusionsThe results of this study suggest that the ONH be assessed biomorphometrically for tamoxifen users reporting visual change that cannot be attributed to non-tamoxifen causes. The ability of modern intraocular imaging techniques to reveal anatomic change on the order of tens of microns may be useful for assessing tamoxifen-induced effects occurring simultaneously elsewhere in the brain, particularly since the presence of small cups is consistent with the possibility of tamoxifen-induced astrocytic swelling.

Mechanism delineating differential effect of an antiestrogen, tamoxifen, on the serum LH and FSH in adult male rats

Tamoxifen, a synthetic non-steroidal antiestrogen with residual estrogenic activity, administered to adult male rats reduces their fertility. A decrease in the circulating LH and testosterone levels with a transient rise or no change in circulating FSH levels was observed. The present study was carried out to delineate the mechanism causing the differential effect of tamoxifen on circulating gonadotropins by correlating it to changes in the hypothalamic LHRH, pituitary gonadotropins and testicular inhibin/activin. Hypothalamus, pituitary-hypothalamus complex (PHC) and intact pituitary (PI) from control and tamoxifen-treated male rats were superfused in vitro, and pulsatile release of LHRH by hypothalamus and that of LH and FSH by the PHC and PI were studied. Concomitantly, testicular immunoexpression of alpha and betaB subunits of inhibin/activin were studied by immunohistochemistry and enzyme-linked immunosorbent assays (ELISA). At 0.4 mg/kg/day dose of tamoxifen a decrease in mean hypothalamic LHRH and LH pulse frequency from PHC construct was observed. FSH pulse frequency was not affected under the same experimental conditions. At the same dose of tamoxifen, testicular expression of both alpha and betaB subunits of inhibin/activin was upregulated. The study demonstrated that reduced circulating LH levels were due to a decrease in hypothalamic LHRH concentration and in LH pulsatility following tamoxifen treatment. The lack of effect on circulating FSH under the same experimental conditions was likely due to its modulation by inhibin and activin.

Differential effects of tamoxifen and I- on three distinguishable chloride currents activated in T84 intestinal cells.

The whole-cell mode of the patch-clamp technique has been used to monitor ionic currents in T84 colonic carcinoma cells. The cells were stimulated by either a cAMP cocktail, ionomycin or hypotonicity. Sizeable currents with distinct kinetics were observed after the stimulation with the different agonists. These kinetically distinct Cl- currents also presented a differential sensitivity to the anti-oestrogen Tamoxifen and to the halide I-. Tamoxifen only inhibits the volume activated Cl- current without affecting the other two. Substitution of extracellular Cl- by I- shifted the reversal potential towards more negative values both in the hypotonicity and ionomycin activated Cl- currents. The cAMP activated current responded to the Cl- substitution by I- with a blockade of both outward and inward currents, in addition to the displacement of the zero current level towards positive values. Thus, the use of these two simple tools, I- and tamoxifen, allows the distinction of Cl- channels in epithelial cells.

Differential effects of tamoxifen and analogs with nonbasic side chains on cell proliferation in vitro.

Structural analogs of the nonsteroidal antiestrogen tamoxifen, in which the basic dimethylaminoethoxy side chain was either absent or replaced with a variety of nonbasic side chains, were examined for their ability to inhibit the proliferation of a hormonally responsive cell line, MCF 7 human breast cancer. The degree of inhibition was compared with relative binding affinities for the estrogen receptor (RE) and a microsomal antiestrogen binding site (AEBS). All modifications resulted in loss of detectable affinity for AEBS. Replacement of the basic side chain of tamoxifen with a series of nonbasic side chains reduced affinity for RE by 78-93% except in the case of 1-(4-(1,2-diphenylbut-1-enyl)phenyl)-2,3-butanediol (ICI 145-680) where affinity was unchanged. When the basic side chain of tamoxifen was replaced by a hydroxyl group, to form the estrogenic analog ICI 141389 (Metabolite E), affinity for RE was reduced by 39%. ICI 141389 was a very weak inhibitor of MCF 7 cell growth, showing no significant growth inhibition at concentrations less than 10 microM. Despite the fact that ICI 145680 and tamoxifen had identical affinities for RE, ICI 145680 was a significantly weaker growth inhibitor than tamoxifen over the concentration range studied, i.e. 0.1-20 microM. Differences in potency were greatest at concentrations greater than 7.5 microM where the effects were not reversed by estradiol and where cytotoxicity played a major role in the decrease in cell numbers induced by tamoxifen. Like tamoxifen, ICI 145680 demonstrated both estrogen-reversible (at concentrations between 0.5-7.5 microM) and estrogen-irreversible (10-20 microM) inhibition of MCF 7 cell proliferation which was associated with a concentration-dependent accumulation of cells in the G0/G1 phase of the cell cycle. In contrast to tamoxifen, however, ICI 145680 appeared not to possess cytotoxic activity. Whereas ICI 145680 was without effect on proliferation of the RE negative human breast cancer cell line, MDA-MB-330, at doses less than 20 microM, tamoxifen inhibited growth at concentrations greater than 5 microM, but with changes in cell cycle kinetic parameters that were markedly different from those seen in RE positive cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Differential effects of two estrogen antagonists on the development of masculine and feminine sexual behavior in hamsters

To determine whether nonsteroidal antiestrogens can be used to investigate the role of aromatization in behavioral masculinization and defeminization, newborn male and female hamsters were administered 0.5 or 5.0 μg of the antiestrogens nafoxidine or tamoxifen on postnatal Days 1 and 2. Other females received 1.0 μg of the synthetic estrogen RU-2858 (RU) alone or in combination with 0.5 or 5.0 μg of nafoxidine or tamoxifen. All animals were tested for the display of masculine and feminine sexual behaviors in adulthood. Nafoxidine, tamoxifen, and RU all reduced lordosis behavior in adult females, indicating that the antiestrogens probably have some estrogenic properties. Nafoxidine had no effect on male mating behavior in female hamsters when given alone; when given to male hamsters or female hamsters receiving a partially masculinizing dose of RU, this compound effectively reduced the frequencies of masculine sexual behaviors (mounts and intromissions) displayed by the treated animals. However, nafoxidine-treated males had the same mating efficiency (ME = intromissions/ mounts) as control males. Tamoxifen, in contrast, facilitated the display of mounting behavior in females when given alone or in combination with RU. Male hamsters receiving 5.0 μg of tamoxifen had high mount frequencies and slightly reduced intromission frequencies, but their ME scores were only half of control levels. Thus nafoxidine itself simultaneously promoted defeminization and antagonized masculinization while tamoxifen appeared to facilitate both processes. The data support the hypothesis that estrogens derived via aromatization from androgens play an important role in both masculinization and defeminization, at least in hamsters. The differential effects of tamoxifen and nafoxidine suggest that these and other antiestrogens might serve as useful tools for dissociating and independently examining these two components of the sexual differentiation process.