Anastrozole monotherapy further improves near-adult height after the initial combined treatment with leuprorelin and anastrozole in early-maturing girls with compromised growth prediction: results from the second phase of the GAIL study.

Background: The first phase of the GAIL study ("Girls treated with an Aromatase Inhibitor and Leuprorelin," ISRCTN11469487) has shown that the combination of anastrozole and leuprorelin for 24 months is safe and effective in improving the predicted adult height (PAH) in girls with early puberty and compromised growth prediction by +1.21 standard deviation score (SDS; +7.51 cm) compared to inhibition of puberty alone, +0.31 SDS (+1.92 cm). Objectives and hypotheses: In the second phase of the GAIL study, we assessed the adult height (AH)/near-adult height (NAH) at the end of the first phase and, in addition, the efficacy of anastrozole monotherapy thereafter in further improving NAH. Methods: We measured the AH (age 16.5 years)/NAH [bone age (BA), 15 years] of the 40 girls included, divided into two matched groups: group A (20 girls on anastrozole + leuprorelin) and group B (20 girls on leuprorelin alone). Group A was further randomized into two subgroups: A1 and A2. Group A1 (n = 10), after completion of the combined therapy, received anastrozole 1 mg/day as monotherapy until BA 14 years, with a 6-month follow-up. Group A2 (n = 10) and group B (n = 20), who received only the combined treatment and leuprorelin alone, respectively, were recalled for evaluation of AH/NAH. Results: AH or NAH exceeded the PAH at the completion of the 2-year initial phase of the GAIL study in all groups, but the results were statistically significant only in group A1: NAH-PAH group A1, +3.85 cm (+0.62 SDS, p = 0.01); group A2, +1.6 cm (+0.26 SDS, p = 0.26); and group B, +1.7 cm (+0.3 SDS, p = 0.08). The gain in group A1 was significantly greater than that in group A2 (p = 0.04) and in group B (p = 0.03). Anastrozole was determined to be safe even as monotherapy in Group A1. Conclusions: In early-maturing girls with compromised growth potential, the combined treatment with leuprorelin and anastrozole for 2 years or until the age of 11 years resulted in a total gain in height of +9.7 cm when continuing anastrozole monotherapy until the attainment of NAH, as opposed to +7.4 cm if they do not continue with the anastrozole monotherapy and +3.6 cm when treated with leuprorelin alone. Thus, the combined intervention ends at the shortest distance from the target height if continued with anastrozole monotherapy until BA 14 years.

The effect of anastrozole therapy on final height and sex hormone levels in pubertal boys receiving growth hormone therapy.

Objective: This research aimed to evaluate retrospectively the effect of anastrozole on height gain and sex hormone levels in pubertal boys receiving growth hormone (GH). Materials and methods: Pubertal boys who received both GH and anastrozole (GH+A) were one-to-one matched with boys who received only GH (GH-Only) for chronological and bone age, pubertal stage and height before the GH initiation, treatment duration and midparental height. Anthropometric measurements throughout treatment and adult heights were compared between the groups. Sex hormone levels were evaluated longitudinally in the GH+A group. Results: Forty-eight cases (24 in each group) were included. There was no statistical difference in adult height between the GH+A and GH-Only (p = 0.071). However, when the analysis was limited to those receiving anastrozole for at least 2 years, mean adult height was higher in the GH+A than in the GH-Only group (173.1 ± 6.2/169.8 ± 5.6 cm, p = 0.044). Despite similar growth rates between the two groups, bone age advancement was slower in the GH+A than in the GH-Only in a mean anastrozole treatment period of 1.59 years (1.37 ± 0.80/1.81 ± 0.98 years, p = 0.001). The greatest increase for FSH, LH, total and free testosterone and decrease for estradiol levels were observed in the third month after anastrozole was started, albeit remaining within the normal ranges according to the actual pubertal stages. Conclusion: Using anastrozole with GH for at least 2 years decelerates the bone age advancement resulting in adult height gain with no abnormality in sex hormone levels. These results suggest anastrozole can be used as an additional treatment to GH for further height gain in pubertal boys.

Amalgamation of quercetin with anastrozole and capecitabine: A novel combination to treat breast and colon cancers - An in vitro study.

Context: Globally, cancer stands as the principle cause of mortality and immediate attention on its treatment options is required. Natural compounds stay at first priority in encountering novel therapeutics without adverse effects. Aim: The aim of the study is to extract flavonol quercetin from leafy vegetables of Anethum graveolens L. and Raphanus sativus L. and find out its potential in combination with drugs used for chemotherapy to reduce the adverse effects of drugs. Settings and Design: Observational study. Materials And Methods: Column chromatography is used for quercetin extraction and anticancer activity of quercetin + anastrozole and quercetin + capecitabine were determined by (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay (MTT), apoptosis assay, cell cycle analysis, mitochondrial membrane potential, and caspase 3 expression. Statistical Analysis Used: Cytotoxic assay results were assessed by mean, standard deviation and ANOVA; and results were compared for determining its significance. Results: The results noted that quercetin at very less concentration (16 and 31 µg/ml on Michigan Cancer Foundation-7 and 43 and 46 µg/ml on COLO 320) in combination with anastrozole and capecitabine was able to control the growth of cells, increase cell death, arrest cell cycle, and induce mitochondrial depolarization and expression of caspase 3. Conclusions: The natural compound used in the present study is effective in treating breast and colon cancer at minimal concentrations in combination with the drugs. This combinational treatment appears to be reported for the first time in the present study.

Anastrozole-mediated modulation of mitochondrial activity by inhibition of mitochondrial permeability transition pore opening: an initial perspective.

The mitochondrial permeability transition pore (mtPTP) plays a vital role in altering the structure and function of mitochondria. Cyclophilin D (CypD) is a mitochondrial protein that regulates mtPTP function and a known drug target for therapeutic studies involving mitochondria. While the effect of aromatase inhibition on the mtPTP has been studied previously, the effect of anastrozole on the mtPTP has not been completely elucidated. The role of anastrozole in modulating the mtPTP was evaluated by docking, molecular dynamics and network-guided studies using human CypD data. The peripheral blood mononuclear cells (PBMCs) of patients with mitochondrial disorders and healthy controls were treated with anastrozole and evaluated for mitochondrial permeability transition pore (mtPTP) function and apoptosis using a flow cytometer. Spectrophotometry was employed for estimating total ATP levels. The anastrozole-CypD complex is more stable than cyclosporin A (CsA)-CypD. Anastrozole performed better than cyclosporine in inhibiting mtPTP. Additional effects included inducing mitochondrial membrane depolarization and a reduction in mitochondrial swelling and superoxide generation, intrinsic caspase-3 activity and cellular apoptosis, along with an increase in ATP levels. Anastrozole may serve as a potential therapeutic agent for mitochondrial disorders and ameliorate the clinical phenotype by regulating the activity of mtPTP. However, further studies are required to substantiate our preliminary findings.Communicated by Ramaswamy H. Sarma.

17beta-estradiol alleviates contusion-induced skeletal muscle injury by decreasing oxidative stress via SIRT1/PGC-1α/Nrf2 pathway.

PURPOSE: This study aimed to investigate the role of 17ß-estradiol (E2) in the repair of contusion-induced myoinjury in mice and to identify the underlying molecular mechanisms. METHODS: In vivo, contusion protocol was performed for preparing mice myoinjury model, and Injection (i.p.) of 17ß-estradiol (E2) or estrogen receptor antagonist ICI 182,780, or ovariectomy (OVX), was used to alter estrogen level of animal models. In vitro, C2C12 myoblasts were treated with H2O2 (oxidative stress inducer), SIRT1 inhibitor EX527, or aromatase inhibitor anastrozole. Serum E2 level was assessed by enzyme-linked immunosorbent assay (ELISA). Muscle damage repair was evaluated by H&E staining and the activities of serum creatine kinase (CK) and lactate dehydrogenase (LDH). The oxidative stress was estimated by the levels of catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA). Western blot was performed to measure the protein expressions of SIRT1, PGC-1α, Nrf2, and HO-1. RESULTS: We observed the elevated serum E2 levels and the upregulated oxidative stress in damaged muscle in female mice after contusion-induction. The E2 administration in vivo alleviated contusion-induced myoinjury in OVX mice by reducing CK and LDH activities, suppressing oxidative stress, and enhancing the expression levels of SIRT1, PGC-1α, Nrf2, and HO-1. These effects were inhibited by treatment with an ERα/ß antagonist. Moreover, EX527 or anastrozole treatment exacerbated H2O2-induced growth inhibition and oxidative stress, and expression downregulation of SIRT1, PGC-1α, Nrf2, and HO-1 in C2C12 cells in vitro. CONCLUSION: Our results suggest that E2 is a positive intervention factor for muscle repair followed contusion-induced myoinjury, through its effects on suppressing oxidative stress via activating the SIRT1/PGC-1α/Nrf2 pathway.

The effect of aromatase inhibitors against possible testis toxicity in pembrolizumab treated rats.

Pembrolizumab is a monoclonal antibody. Anastrozole is an infertility inhibitor of aromatase. Resveratrol is an antioxidant polyphenol in the reproductive system. This study was planned to demonstrate the protective effects of anastrozole and resveratrol against pembrolizumab-induced reproductive damage. Forty-two Sprague-Dawley rats were used in the study. Groups: The control, Pembrolizumab (PEMB), PEMB + Anastrazol (ANAST), PEMB + Resveratrol (RES), RES, and ANAST groups. At the end of the experiment, rats were euthanased under anaesthesia. Tissue samples were taken from rats for biochemical, histological, and ELISA evaluations. Tissues were subjected to routine tissue follow-up for histological analysis. Biochemically, thiobarbituric acid reactive substance (TBARS), glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) levels were measured. Sperm motility, abnormal sperm rate, and epididymal sperm concentration were examined spermatologically. Serum testosterone and programmed cell death-1 (PD-1) levels were measured using the ELISA. TBARS levels were significantly increased and GSH, SOD, GPx, and CAT levels were mitigated in PEMB-treated rats. Histologically; Control, ANAST, and RES groups testis samples were observed with normal histological appearance. Histological damage was detected in seminiferous tubule structures in testicular tissue in the PEMB group. In treatment groups, this damage was decreased. In addition, PD-1 and testosterone levels were evaluated by the ELISA method. ANAST and RES have therapeutic effects against reproductive damage caused by PEMB.

Design and synthesis of marine sesterterpene analogues as novel estrogen receptor α degraders for breast cancer treatment.

Targeted protein degradation using small molecules is an intriguing strategy for drug development. The marine sesterterpene compound MHO7 had been reported to be a potential ERα degradation agent. In order to further improve its biological activity, two series of novel MHO7 derivatives with long side chains were designed and identified as novel selective estrogen receptor down-regulators (SERDs). The growth inhibition activity of the novel SERD compounds were significantly affected by the type and length of the side chain. Most of the derivatives were significantly more potent than MHO7 against both drug-sensitive and drug-resistant breast cancer cells. Among them, compound 16a, with IC50 values of 0.41 µM against MCF-7 cell lines and 9.6-fold stronger than MHO7, was the most potential molecule. A whole-genome transcriptomic analysis of MCF-7 cells revealed that the mechanism of 16a against MCF-7 cell was similar with that of MHO7. The estrogen signaling pathway was the most affected among the disturbed genes, but the ERα degradation activity of 16a was observed higher than that of MHO7. Other effects of 16a were confirmed similar with MHO7, which means that the basic mechanisms of the derivatives are the same with the ophiobolin backbone, i.e. the degradation of ERα is mediated via proteasome-mediated process, the induction of apoptosis and the cell cycle arrest at the G1 phase. Meanwhile, a decrease of mitochondrial membrane potential and an increase of cellular ROS were also detected. Based on these results, as a novel modified ophiobolin derived compound, 16a may warrant further exploitation as a promising SERD candidate agent for the treatment of breast cancer.

Anastrozole Regulates Fatty Acid Synthase in Breast Cancer.

Our previous matched case-control study of postmenopausal women with resected early-stage breast cancer revealed that only anastrozole, but not exemestane or letrozole, showed a significant association between the 6-month estrogen concentrations and risk of breast cancer. Anastrozole, but not exemestane or letrozole, is a ligand for estrogen receptor α. The mechanisms of endocrine resistance are heterogenous and with the new mechanism of anastrozole, we have found that treatment of anastrozole maintains fatty acid synthase (FASN) protein level by limiting the ubiquitin-mediated FASN degradation, leading to increased breast cancer cell growth. Mechanistically, anastrozole decreases the guided entry of tail-anchored proteins factor 4 (GET4) expression, resulting in decreased BCL2-associated athanogene cochaperone 6 (BAG6) complex activity, which in turn, prevents RNF126-mediated degradation of FASN. Increased FASN protein level can induce a negative feedback loop mediated by the MAPK pathway. High levels of FASN are associated with poor outcome only in patients with anastrozole-treated breast cancer, but not in patients treated with exemestane or letrozole. Repressing FASN causes regression of breast cancer cell growth. The anastrozole-FASN signaling pathway is eminently targetable in endocrine-resistant breast cancer.

Differential biological effects of aromatase inhibitors: Apoptosis, autophagy, senescence and modulation of the hormonal status in breast cancer cells.

Estrogen receptor-positive (ER+) breast carcinomas are the most common subtype, corresponding to 60% of the cases in premenopausal and 75% in postmenopausal women. The third-generation of aromatase inhibitors (AIs), the non-steroidal Anastrozole (Ana) and Letrozole (Let) and the steroidal Exemestane (Exe), are considered a first-line endocrine therapy for postmenopausal women. Despite their clinical success, the development of resistance is the major setback in clinical practice. Nevertheless, the lack of cross-resistance between AIs hints that these drugs may act through distinct mechanisms. Therefore, this work studied the different effects induced by AIs on biological processes, such as cell proliferation, death, autophagy and senescence. Moreover, their effects on the regulation of the hormonal environment were also explored. The non-steroidal AIs induce senescence, through increased YPEL3 expression, on aromatase-overexpressing breast cancer cells (MCF-7aro), whereas Exe promotes a cytoprotective autophagy, thus blocking senescence induction. In addition, in a hormone-enriched environment, the non-steroidal AIs prevent estrogen signaling, despite up-regulating the estrogen receptor alpha (ERα), while Exe down-regulates ERα and maintains its activation. In these conditions, all AIs up-regulate the androgen receptor (AR) which blocks EGR3 transcription in Exe-treated cells. On the other hand, in hormone-depleted conditions, a crosstalk between AR and ERα occurs, enhancing the estrogenic effects of Exe. This indicates that Exe modulates both ERα and AR, while Ana and Let act as pure AIs. Thus, this study highlights the potential clinical benefit of combining AR antagonists with Exe and discourages the sequential use of Exe as second-line therapy in postmenopausal breast cancer.

Determining the Interaction Behavior of Calf Thymus DNA with Anastrozole in the Presence of Histone H1: Spectroscopies and Cell Viability of MCF-7 Cell Line Investigations.

The interaction of calf thymus DNA (ct DNA) with anastrozole, which is acknowledged as an antineoplastic drug, has been enquired into in the absence and presence of histone H1, through the means of absorbance, fluorescence, circular dichroism spectroscopy, viscosity, thermal melting, and molecular modeling techniques. In addition, the effects of anastrozole on MCF 7 cell line have been thoroughly investigated. Fluorescence spectroscopy results have indicated that quenching mechanism of ct DNA-anastrozole are known as static quenching procedures, since the Stern-Volmer quenching constant (KSV) seems to face a decrease as the temperature is enhanced; this is a significant evidence for intercalative binding mode of anastrozole with ct DNA. Regarding the ternary system in the presence of H1, the constant of Stern-Volmer quenching was increased as the temperature was heightened. The thermodynamic parameters suggested that the binding could be characterized as exothermic by negative and positive enthalpy and entropy changes in both binary and ternary systems, respectively. It is vital to mention that hydrogen bonds and hydrophobic contributions play significant roles in anastrozole association to ct DNA in the absence and presence of H1. In accordance to the absorption spectroscopy and melting temperature curve outcomes, the binding mode of anastrozole with ct DNA in absence and presence of H1 was indicative of intercalative and nonintercalative bindings, respectively. The viscosity results as binary and ternary systems, which have been elucidated from a sensitive viscometer, have confirmed the fluorescence spectroscopy determinations. The intercalation of anastrozole to ct DNA seemed to be significantly related to an induced reduction in MCF-7 cell proliferation. The molecular modeling results have suggested that anastrozole could bind to H1 in ct DNA-H1 complex in ternary systems, which supports the conclusions that have been obtained from experimental data.

Vitamin D Compounds PRI-2191 and PRI-2205 Enhance Anastrozole Activity in Human Breast Cancer Models.

1,25-Dihydroxycholecalciferol, the hormonally active vitamin D3 metabolite, is known to exhibit therapeutic effects against breast cancer, mainly by lowering the expression of estrogen receptors and aromatase activity. Previously, the safety of the vitamin D active metabolite (24R)-1,24-dihydroxycholecalciferol (PRI-2191) and 1,25(OH)2D3 analog PRI-2205 was tested, and the in vitro activity of these analogs against different cancer cell lines was studied. We determined the effect of the two vitamin D compounds on anastrozole (An) activity against breast cancer based on antiproliferative activity, ELISA, flow cytometry, enzyme inhibition potency, PCR, and xenograft study. Both the vitamin D active metabolite and synthetic analog regulated the growth of not only estrogen receptor-positive cells (T47D and MCF-7, in vitro and in vivo), but also hormone-independent cancer cells such as SKBR-3 (HER-2-positive) and MDA-MB-231 (triple-negative), despite their relatively low VDR expression. Combined with An, PRI-2191 and PRI-2205 significantly inhibited the tumor growth of MCF-7 cells. Potentiation of the antitumor activity in combined treatment of MCF-7 tumor-bearing mice is related to the reduced activity of aromatase by both An (enzyme inhibition) and vitamin D compounds (switched off/decreased aromatase gene expression, decreased expression of other genes related to estrogen signaling) and by regulation of the expression of the estrogen receptor ERα and VDR.

Long-term Effect of Aromatase Inhibition in Aromatase Excess Syndrome.

CONTEXT: Aromatase excess syndrome (AEXS) is a very rare disorder characterized by prepubertal gynecomastia, bone age acceleration, and early growth arrest. Heterozygote submicroscopic rearrangements within the promotor of CYP19A1 result in overexpression of aromatase and enhanced aromatization of androgens. OBJECTIVE: The objective was to study long-term treatment effects of an aromatase inhibitor. METHODS: Data from 7 boys with AEXS were retrospectively collected. Genetic analysis revealed upstream of CYP19A1 a 165 901 bp deletion in 4 German cousins, a 198 662 bp deletion in 2 Japanese brothers, and a 387 622 bp tandem duplication in a Japanese boy. RESULTS: All boys developed prepubertal gynecomastia, at median 9.0 years of age (range: 7.0-11.0). Height was +1.20 standard deviation score (SDS) (-0.24 to +1.98); predicted adult height was -1.29 SDS (-3.29 to +1.09). Four boys were treated with 1.0 mg of anastrozole daily, while 3 reached adult height untreated. Treatment with anastrozole was stopped after 5.6 years (4.0-6.8). Three treated boys exceeded their prognosis by 2.4, 6.9, and 8.1 cm, while 1 untreated boy fell below the prognosis by 8.6 cm. One treated with a low dose and 2 untreated reached their prognosis. Adult heights were -0.91 SDS with anastrozole (-2.86 to -0.29) and -0.15 SDS without (-2.31 to -0.03). Distance to target height was -0.22 SDS with anastrozole (-1.72 to +0.52) and +0.54 SDS without (+0.23 to +1.30). CONCLUSION: Spontaneous growth in AEXS varied, even in the same family. Our data suggest that early started, long-term inhibition by anastrozole promotes adult height in boys with AEXS.

Biophysical Insight into the Interaction of Human Lysozyme with Anticancer Drug Anastrozole: A Multitechnique Approach.

In the present study, we employ fluorescence spectroscopy, dynamic light scattering, and molecular docking methods. Binding of anticancer drug anastrozole with human lysozyme (HL) is studied. Binding of anastrozole to HL is moderate but spontaneous. There is anastrozole persuaded hydrodynamic change in HL, leading to molecular compaction. Binding of anastrozole to HL also decreased in vitro lytic activity of HL. Molecular docking results suggest the electrostatic interactions and van der Waals forces played key role in binding interaction of anastrozole near the catalytic site. Binding interaction of anastrozole to proteins other than major transport proteins in blood can significantly affect pharmacokinetics of this molecule. Hence, rationalizing drug dosage is important. This study also points to unrelated effects that small molecules bring in the body that are considerable and need thorough investigation.

Pharmacogenomics of aromatase inhibitors in postmenopausal breast cancer and additional mechanisms of anastrozole action.

Aromatase inhibitors (AIs) reduce breast cancer recurrence and prolong survival, but up to 30% of patients exhibit recurrence. Using a genome-wide association study of patients entered on MA.27, a phase III randomized trial of anastrozole versus exemestane, we identified a single nucleotide polymorphism (SNP) in CUB And Sushi multiple domains 1 (CSMD1) associated with breast cancer-free interval, with the variant allele associated with fewer distant recurrences. Mechanistically, CSMD1 regulates CYP19 expression in an SNP- and drug-dependent fashion, and this regulation is different among 3 AIs: anastrozole, exemestane, and letrozole. Overexpression of CSMD1 sensitized AI-resistant cells to anastrozole but not to the other 2 AIs. The SNP in CSMD1 that was associated with increased CSMD1 and CYP19 expression levels increased anastrozole sensitivity, but not letrozole or exemestane sensitivity. Anastrozole degrades estrogen receptor α (ERα), especially in the presence of estradiol (E2). ER+ breast cancer organoids and AI- or fulvestrant-resistant breast cancer cells were more sensitive to anastrozole plus E2 than to AI alone. Our findings suggest that the CSMD1 SNP might help to predict AI response, and anastrozole plus E2 serves as a potential new therapeutic strategy for patients with AI- or fulvestrant-resistant breast cancers.

27-Hydroxycholesterol contributes to cognitive deficits in APP/PS1 transgenic mice through microbiota dysbiosis and intestinal barrier dysfunction.

BACKGROUND: Research on the brain-gut-microbiota axis has led to accumulating interest in gut microbiota dysbiosis and intestinal barrier dysfunction in Alzheimer's disease (AD). Our previous studies have demonstrated neurotoxic effects of 27-hydroxycholesterol (27-OHC) in in vitro and in vivo models. Here, alterations in the gut microbiota and intestinal barrier functions were investigated as the possible causes of cognitive deficits induced by 27-OHC treatment. METHODS: Male APP/PS1 transgenic and C57BL/6J mice were treated for 3 weeks with 27-OHC (5.5 mg/kg/day, subcutaneous injection) and either a 27-OHC synthetase inhibitor (anastrozole, ANS) or saline. The Morris water maze and passive avoidance test were used to assess cognitive impairment. Injuries of the intestine were evaluated by histopathological examination. Intestinal barrier function was assessed by plasma diamine oxidase (DAO) activity and D-lactate. Systemic and intestinal inflammation were evaluated by IL-1ß, TNF-α, IL-10, and IL-17 concentrations as determined by ELISA. The fecal microbiome and short-chain fatty acids (SCFAs) were analyzed using 16S rDNA sequencing and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Tight junction proteins were evaluated in the ileum and colon by qRT-PCR and Western blots. Tight junction ultrastructure was examined by transmission electron microscopy. RESULTS: Treatment with 27-OHC resulted in severe pathologies in the ileum and colon. There was impaired intestinal barrier integrity as indicated by dilated tight junctions and downregulation of tight junction proteins, including occludin, claudin 1, claudin 5, and ZO-1, and signs of inflammation (increased IL-1ß, TNF-α, and IL-17). Fecal 16S rDNA sequencing and taxonomic analysis further revealed a decreased abundance of Roseburia and reduced fecal levels of several SCFAs in 27-OHC-treated mice. Meanwhile, co-treatment with ANS reduced intestinal inflammation and partially preserved intestinal barrier integrity in the presence of 27-OHC. CONCLUSIONS: The current study demonstrates for the first time that 27-OHC treatment aggravates AD-associated pathophysiological alterations, specifically gut microbiota dysbiosis and intestinal barrier dysfunction, which suggests that the gut microbiome and intestinal barrier function warrant further investigation as potential targets to mitigate the neurotoxic impact of 27-OHC on cognitive function and the development of AD.

Rescuing Dicer expression in inflamed colon tissues alleviates colitis and prevents colitis-associated tumorigenesis.

Chronic inflammation is known to promote carcinogenesis; Dicer heterozygous mice are more likely to develop colitis-associated tumors. This study investigates whether Dicer is downregulated in inflamed colon tissues before malignancy occurs and whether increasing Dicer expression in inflamed colon tissues can alleviate colitis and prevent colitis-associated tumorigenesis. Methods: Gene expression in colon tissues was analyzed by immunohistochemistry, immunoblots, and real-time RT-PCR. Hydrogen peroxide or N-acetyl-L-cysteine was used to induce or alleviate oxidative stress, respectively. Mice were given azoxymethane followed by dextran sulfate sodium to induce colitis and colon tumors. Berberine, anastrozole, or pranoprofen was used to rescue Dicer expression in inflammatory colon tissues. Results: Oxidative stress repressed Dicer expression in inflamed colon tissues by inducing miR-215 expression. Decreased Dicer expression increased DNA damage and cytosolic DNA and promoted interleukin-6 expression upon hydrogen peroxide treatment. Dicer overexpression in inflamed colon tissues alleviated inflammation and repressed colitis-associated carcinogenesis. Furthermore, we found that anastrozole, berberine, and pranoprofen could promote Dicer expression and protect cells from hydrogen peroxide-induced DNA damage, thereby reducing cytosolic DNA and partially repressing interleukin-6 expression upon hydrogen peroxide treatment. Rescuing Dicer expression using anastrozole, berberine, or pranoprofen in inflamed colon tissues alleviated colitis and prevented colitis-associated tumorigenesis. Conclusions: Dicer was downregulated in inflamed colon tissues before malignancy occurred. Decreased Dicer expression further exaggerated inflammation, which may promote carcinogenesis. Anastrozole, berberine, and pranoprofen alleviated colitis and colitis-associated tumorigenesis by promoting Dicer expression. Our study provides insight into potential colitis treatment and colitis-associated colon cancer prevention strategies.

Efficacy of a novel orally active SERD AZD9496 against hormone dependent post-menopausal breast cancer depends on inhibition of cellular aromatase activity.

Treatment of hormone sensitive breast cancer tumors with endocrine therapy such as antiestrogens or aromatase inhibitors has improved the outcome significantly. Studies including our own have shown that downregulation of ERα with pure antiestrogen fulvestrant in combination with aromatase inhibitors may prolong responsiveness of the tumors to endocrine therapy. Fulvestrant has been studied as second line or first line treatment for post-menopausal hormone receptor positive breast cancers as a single agent or in combination with AIs. Studies have also suggested that further escalation of dose may improve benefit. However, dose escalation of fulvestrant, which is administered via intramuscular injection, is difficult due to its poor solubility. To overcome this shortcoming of an injectable drug, a novel orally active antiestrogen, AZD9496 was developed. In addition to being orally active, AZD9496 is designed as a selective ERα downregulator (SERD). In the current study, we compared the effect of AZD9496 and fulvestrant on the growth of MCF-7Ca (human estrogen receptor positive MCF-7 cells stably transfected with human placental aromatase gene) xenografts grown in ovariectomized athymic nude mice. AZD9496 was also compared to fulvestrant in vitro as a single agent or in combination with anastrozole. Our current study shows that AZD9496 is equally effective as fulvestrant at controlling the growth of hormone sensitive human breast cancer tumors. Similar to fulvestrant, AZD9496 inhibits cellular aromatase activity through ERα mediated signaling. However, unlike fulvestrant, combination of AZD9496 with anastrozole did not produce increased tumor inhibition. Our results show that AZD9496 was significantly better at inhibiting cellular aromatase which contributed to its anticancer activity. Next, we measured the effect of AZD9496 on the mouse uterus. Uterine weight of mice treated with AZD9496 was significantly lower than that for mice treated with androstenedione. This reduction in uterine weight was due to AZD9496 mediated inhibition of aromatase activity and not a direct effect on uterine ERα expression. We also observed that anti-cancer efficacy of AZD9496 depended on its ability to inhibit cellular aromatase. These results suggest that AZD9496 may be a better alternative to fulvestrant due to its selectivity for mammary ER and ability to inhibit aromatase in addition of downregulating ERα that can be obtained upon oral administration. As such, AZD9496 may prove to be a better option than fulvestrant for the treatment of hormone sensitive human breast cancer.

Effects of anastrozole on Ki-67 antigen expression in the vaginal epithelium of female rats in persistent estrus.

OBJECTIVES: Aromatase inhibitors are the first-choice drugs for the treatment of hormone sensitive breast cancer. However, in addition to the scarcity of studies, there are controversies about their effects on vaginal epithelial cell proliferation in rats, especially those in persistent estrus. METHODS: To investigate vaginal epithelial cell proliferation by Ki-67 antigen expression, persistent estrus was induced in 42 randomly selected rats. These rats were randomly divided into 2 groups: group I (control, n=21), which received 0.1 mL of propylene glycol (vehicle) daily, and group II (experimental, n=21), which received 0.5 mg/kg or 0.125 mg/day of anastrozole diluted with 0.1 mL of propylene glycol. RESULTS: Light microscopy showed a higher concentration of cells with brown Ki-67 stained nuclei in the control compared to the experimental group. The mean percentage of Ki-67 stained nuclei per 500 cells in the vaginal epithelium was 68.64±2.64 and 30.46±2.00 [mean±standard error of the mean (SEM)] in the control and experimental groups, respectively (p<0.003). CONCLUSION: This study showed that anastrozole, at the dose and treatment duration selected, significantly decreased cell proliferation in the vaginal mucosa of the rats in persistent estrus.

Combined Anastrozole and Antiplatelet Therapy Treatment Differentially Promotes Breast Cancer Cell Survival.

Thromboembolic disorders are the second leading cause of death in breast cancer. Antiplatelet therapy combined with cancer therapy is a potential treatment strategy against cancer-associated thromboembolic disorders; however, the efficacy of such dual treatment has not been established. This study reports novel findings on the response of hormone-dependent breast cancer cell lines (MCF7/T47D) following 24 h treatment with Anastrozole, combined with Aspirin and Clopidogrel cocktail; and Atopaxar. Neutral red and lactate dehydrogenase assays were conducted to assess viability and cytotoxicity respectively. Flow cytometric Annexin-V/PI assay was used to assess the mode of cell death. Morphological alterations were studied using scanning electron microscopy. Statistical analysis was conducted using Statistica V13. Definitive outcomes were established with flow cytometric detection of phosphatidylserine exposure and propidium iodide staining, complemented with ultrastructural analysis. Results showed that a few cells were undergoing death mainly through secondary necrosis. Morphological features suggesting induced cell motility (pseudopodia/ruffled membranes) were observed in both cell lines; notably, T47D cells presented pronounced features than MCF7 cells. Overall, these findings suggest that such combined treatment may differentially promote cell survival, inducing a more aggressive breast cancer phenotype.

Leptin Signaling Contributes to Aromatase Inhibitor Resistant Breast Cancer Cell Growth and Activation of Macrophages.

Obesity represents a risk factor for breast cancer development and therapy resistance, but the molecular players underling these links are unclear. Here, we identify a role for the obesity-cytokine leptin in sustaining aromatase inhibitor (AI) resistant growth and progression in breast cancer. Using as experimental models MCF-7 breast cancer cells surviving long-term treatment with the AI anastrozole (AnaR) and Ana-sensitive counterparts, we found that AnaR cells expressed higher levels of leptin and its receptors (ObR) along with a constitutive activation of downstream effectors. Accordingly, leptin signaling inhibition reduced only AnaR cell growth and motility, highlighting the existence of an autocrine loop in mechanisms governing drug-resistant phenotypes. In agreement with ObR overexpression, increasing doses of leptin were able to stimulate to a greater extent growth and migration in AnaR than sensitive cells. Moreover, leptin contributed to enhanced crosstalk between AnaR cells and macrophages within the tumor microenvironment. Indeed, AnaR, through leptin secretion, modulated macrophage profiles and increased macrophage motility through CXCR4 signaling, as evidenced by RNA-sequencing, real-time PCR, and immunoblotting. Reciprocally, activated macrophages increased AnaR cell growth and motility in coculture systems. In conclusion, acquired AI resistance is accompanied by the development of a leptin-driven phenotype, highlighting the potential clinical benefit of targeting this cytokine network in hormone-resistant breast cancers, especially in obese women.