Modeling of Mouse Experiments Suggests that Optimal Anti-Hormonal Treatment for Breast Cancer is Diet-Dependent.

Estrogen receptor positive breast cancer is frequently treated with anti-hormonal treatment such as aromatase inhibitors (AI). Interestingly, a high body mass index has been shown to have a negative impact on AI efficacy, most likely due to disturbances in steroid metabolism and adipokine production. Here, we propose a mathematical model based on a system of ordinary differential equations to investigate the effect of high-fat diet on tumor growth. We inform the model with data from mouse experiments, where the animals are fed with high-fat or control (normal) diet. By incorporating AI treatment with drug resistance into the model and by solving optimal control problems we found differential responses for control and high-fat diet. To the best of our knowledge, this is the first attempt to model optimal anti-hormonal treatment for breast cancer in the presence of drug resistance. Our results underline the importance of considering high-fat diet and obesity as factors influencing clinical outcomes during anti-hormonal therapies in breast cancer patients.

The significant improvement in ovarian PCOS syndrome using hydralazine and alendronate aromatase inhibitor FDA-approved drugs in Wistar rat models.

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. The aim of this study was to investigate the therapeutic potential of vitamin C, glutamine, mesalazine, hydralazine, and alendronate as new drug candidates for the treatment of letrozole-induced PCOS in female Wistar rats. PCOS was induced in rats by intramuscular injection of estradiol valerate (2 mg/kg body weight for 28 days). The rats then received normal saline (PCOS group), letrozole (0.5 mg/kg), vitamin C (100 mg/kg), glutamine (1000 mg/kg), mesalazine (200 mg/kg), hydralazine (30 mg/kg), and alendronate (17.5 mg/kg). Serum testosterone, LH, FSH, estradiol and progesterone levels were determined by ELISA method. H&E staining was used for histological analysis in the ovarian tissues. The groups treated with hydralazine and alendronate, show a significant decrease in testosterone, LH hormone, cystic and atretic follicles, and a significant increase in the number of single layer, multilayer, antral, graafian follicles and the volume of corpus luteum as compared to the PCOS group. Hydrolazine and alendronate appear to be effective in restoring folliculogenesis and increasing ovulation in PCOS rat. So that the natural process of ovulation and the improvement of the histology of polycystic ovaries and its shift towards healthy and active ovaries were observed. This finding supports the potential beneficial effect of hydrolazine and alendronate on improving PCOS complication.

Effect of Aromatase Inhibitor Letrozole on the Placenta of Adult Albino Rats: A Histopathological, Immunohistochemical, and Biochemical Study.

Background: Letrozole, an aromatase inhibitor, has recently been introduced as the preferred treatment option for ectopic pregnancy. To date, no study has investigated the effect of letrozole alone on placental tissue. The present study aimed to evaluate the effect of different doses of letrozole on the placenta of rats and to clarify the underlying mechanism. Methods: Sixty pregnant female rats were equally divided into three groups, namely the control group (GI), low-dose (0.5 mg/Kg/day) letrozole group (GII), which is equivalent to the human daily dose (HED) of 5 mg, and high-dose (1 mg/Kg/day) letrozole group (GIII), equivalent to the HED of 10 mg. Letrozole was administered by oral gavage daily from day 6 to 16 of gestation. Data were analyzed using a one-way analysis of variance followed by Tukey's post hoc test and Chi square test. P<0.05 was considered statistically significant. Results: Compared to the GI and GII groups, high-dose letrozole significantly increased embryonic mortality with a high post-implantation loss rate (P<0.001) and significantly reduced the number of viable fetuses (P<0.001) and placental weight (P<0.001) of pregnant rats. Moreover, it significantly reduced placental estrogen receptor (ER) and progesterone receptor (PR) (P<0.001) and the expression of vascular endothelial growth factor (P<0.001), while increasing the apoptotic index of cleaved caspase-3 (P<0.001). Conclusion: Letrozole inhibited the expression of ER and PR in rat placenta. It interrupted stimulatory vascular signals causing significant apoptosis and placental vascular dysfunction. Letrozole in an equivalent human daily dose of 10 mg caused a high post-implantation loss rate without imposing severe side effects.

Evaluating flavonoids as potential aromatase inhibitors for breast cancer treatment: In vitro studies and in silico predictions.

Aromatase inhibitors are commonly employed in the treatment of hormone-dependent breast cancers, and flavonoids have emerged as a promising alternative to existing drug classes with unfavorable side effects. In this study, we conducted in vitro investigations into CYP19A1 (aromatase) inhibitory potential of 14 flavonoids, including pinocembrin, sakuranetin, eriodictyol, liquiritigenin, naringenin, hesperetin, flavanone, baicalein, chrysin, nobiletin, luteolin, sinensetin, tricin, and primuletin. Flavonoids displaying inhibitory activity were further assessed using in silico tools, such as molecular docking to predict binding affinities, as well as SwissADME, admetSAR, and QED (Quantitative Estimate of Drug-likeness) for drug-likeness prediction. Flavonoids with IC50 values less than 10 µM, pinocembrin, eriodictyol, naringenin, liquirtigenin, sakuranetin, and chrysin, exhibited favorable physicochemical properties and ADME profiles, suggesting their potential for development as novel flavonoid-based aromatase inhibitors. This study would provide valuable insights for the development of flavonoid-based aromatase inhibitors for the treatment of breast cancer.

Letrozole cotreatment progestin-primed ovarian stimulation in women undergoing controlled ovarian stimulation for in vitro fertilization.

AIM: To investigate the impact of letrozole cotreatment progestin-primed ovarian stimulation (PPOS) (Le PPOS) in controlled ovarian stimulation (COS) and the pregnancy outcomes in frozen-thawed embryo transfer cycles. METHODS: This retrospective cohort study included women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). A total of 2575 cycles were included (1675 in the Le PPOS group and 900 in the PPOS group). The primary outcome was the clinical pregnancy rates. The secondary outcome was the live birth rates. RESULTS: In this study, propensity score matching (PSM) was performed to create a perfect match of 379 patients in each group. After matching, the numbers of oocytes retrieved, mature oocytes, fertilization, and clinical pregnancy rates were more favorable in the Le PPOS group than in the PPOS group (all p < 0.05). The multivariable analysis showed that the clinical pregnancy rate was higher in the Le PPOS than in the PPOS group (odds ratio = 1.46, 95% confidence interval: 1.05-2.04, p = 0.024) after adjusting for potentially confounding factors (age, anti-Müllerian hormone levels, antral follicular count, the type of embryo transferred, number of transferred embryos, body mass index, and follicular stimulating hormone and estradiol levels on starting day). CONCLUSIONS: This retrospective study with a limited sample size suggests that the Le PPOS protocol might be an alternative to the PPOS protocol in women undergoing COS and could lead to better pregnancy outcomes. The results should be confirmed using a formal randomized controlled trial.

Acetyl-CoA carboxylase 1 controls a lipid droplet-peroxisome axis and is a vulnerability of endocrine-resistant ER+ breast cancer.

Targeting aromatase deprives ER+ breast cancers of estrogens and is an effective therapeutic approach for these tumors. However, drug resistance is an unmet clinical need. Lipidomic analysis of long-term estrogen-deprived (LTED) ER+ breast cancer cells, a model of aromatase inhibitor resistance, revealed enhanced intracellular lipid storage. Functional metabolic analysis showed that lipid droplets together with peroxisomes, which we showed to be enriched and active in the LTED cells, controlled redox homeostasis and conferred metabolic adaptability to the resistant tumors. This reprogramming was controlled by acetyl-CoA-carboxylase-1 (ACC1), whose targeting selectively impaired LTED survival. However, the addition of branched- and very long-chain fatty acids reverted ACC1 inhibition, a process that was mediated by peroxisome function and redox homeostasis. The therapeutic relevance of these findings was validated in aromatase inhibitor-treated patient-derived samples. Last, targeting ACC1 reduced tumor growth of resistant patient-derived xenografts, thus identifying a targetable hub to combat the acquisition of estrogen independence in ER+ breast cancers.

Novel mitochondrial and DNA damaging fluorescent Calix[4]arenes bearing isatin groups as aromatase inhibitors: Design, synthesis and anticancer activity.

Breast cancer causes a high rate of mortality all over the world. Therefore, the present study focuses on the anticancer activity of new lower rim-functionalized calix[4]arenes integrated with isatin and the p-position of calixarenes with 1,4-dimethylpyridinium iodine against various human cancer cells such as MCF-7 and MDA-MB-231 breast cancer cell lines, as well as the PNT1A healthy epithelial cell line. It was observed that compound 6c had the lowest values in MCF-7 (8.83 µM) and MDA-MB-231 (3.32 µM). Cell imaging and apoptotic activity studies were performed using confocal microscopy and flow cytometry, respectively. The confocal imaging studies with 6c showed that the compound easily entered the cell, and it was observed that 6c accumulated in the mitochondria. The Comet assay test was used to detect DNA damage of compounds in cells. It was found that treated cells had abnormal tail nuclei and damaged DNA structures compared with untreated cells. In vitro human aromatase enzyme inhibition profiles showed that compound 6c had a remarkable inhibitory effect on aromatase. Compound 6c displayed a significant inhibition capacity on aromatase enzyme with the IC50 value of 0.104 ± 0.004 µM. Thus, not only the anticancer activity of the new fluorescent derivatives, which are the subject of this study, but the aromatase inhibitory profiles have also been proven.

Molecular and clinical effects of aromatase inhibitor therapy on skeletal muscle function in early-stage breast cancer.

We evaluated biochemical changes in skeletal muscle of women with breast cancer initiating aromatase inhibitors (AI), including oxidation of ryanodine receptor RyR1 and loss of stabilizing protein calstabin1, and detailed measures of muscle function. Fifteen postmenopausal women with stage I-III breast cancer planning to initiate AI enrolled. Quadriceps muscle biopsy, dual-energy x-ray absorptiometry, isokinetic dynamometry, Short Physical Performance Battery, grip strength, 6-min walk, patient-reported outcomes, and serologic measures of bone turnover were assessed before and after 6 months of AI. Post-AI exposure, oxidation of RyR1 significantly increased (0.23 ± 0.37 vs. 0.88 ± 0.80, p < 0.001) and RyR1-bound calstabin1 significantly decreased (1.69 ± 1.53 vs. 0.74 ± 0.85, p < 0.001), consistent with dysfunctional calcium channels in skeletal muscle. Grip strength significantly decreased at 6 months. No significant differences were seen in isokinetic dynamometry measures of muscle contractility, fatigue resistance, or muscle recovery post-AI exposure. However, there was significant correlation between oxidation of RyR1 with muscle power (r = 0.60, p = 0.02) and muscle fatigue (r = 0.57, p = 0.03). Estrogen deprivation therapy for breast cancer resulted in maladaptive changes in skeletal muscle, consistent with the biochemical signature of dysfunctional RyR1 calcium channels. Future studies will evaluate longer trajectories of muscle function change and include other high bone turnover states, such as bone metastases.

Targeting aromatase to restrain oestrogen production and developing efficacious interventions against ER-positive cancer.

Being the most frequently diagnosed disease, breast cancer is mainly classified as ER+ cancers due to the detection of estrogen receptor (ER) expression. Irrespetive of the successes achieved in the treatment of ER+ cancers by the use of selective estrogen receptor modulator (SERM) drugs like tamoxifen, resistance to the drug is a major clinical obstacle. Working on alternative treatment approaches, here, on the basis of mode of action of aromatase for the conversion of androstenedione to oestrogen, a series of compounds was developed. Results of all the experiments performed with these compounds led to the identification of three highly potent compounds 5d, 5e and 7d with their IC50 61.0, 83.0 and 54.0 nM for aromatase. Indicating their effectiveness in the treatment of ER+ cancers, appreciable tumor growth inhibitory activities of these compounds were observed against breast cancer cell lines. Further, the physico-chemical experiments including plasma protein binding, HSA binding, kinetic studies, solubility, ADME properties and molecular modelling studies supported the drug like features of the compounds.

Aromatase Inhibitors as a Promising Direction for the Search for New Anticancer Drugs.

Aromatase is an enzyme that plays a crucial role in the biosynthesis of estrogens, which are hormones that contribute to the growth of certain types of breast cancer. In particular, aromatase catalyzes the conversion of androgens (male hormones) into estrogens (female hormones) in various tissues, including the adrenal glands, ovaries, and adipose tissue. Given the role of estrogen in promoting the growth of hormone-receptor-positive breast cancers, aromatase has become an important molecular target for the development of anticancer agents. Aromatase inhibitors can be classified into two main groups based on their chemical structure: steroidal and non-steroidal inhibitors. This work presents a review of the literature from the last ten years regarding the search for new aromatase inhibitors. We present the directions of search, taking into account the impact of structure modifications on anticancer activity.

Effect of oestrogen modulation on semen parameters in men with secondary hypogonadism: Systematic review and meta-analysis.

BACKGROUND: Selective oestrogen receptor modulators and aromatase inhibitors stimulate endogenous gonadotrophins and testosterone in men with hypogonadism. There are no systematic reviews/meta-analyses assessing the effects of selective oestrogen receptor modulators/aromatase inhibitors on semen parameters in men with secondary hypogonadism. OBJECTIVES: To assess the effect of monotherapy or a combination of selective oestrogen receptor modulators/aromatase inhibitors on sperm parameters and/or fertility in men with secondary hypogonadism. MATERIALS AND METHODS: A systematic search was conducted in PubMed, MEDLINE, Cochrane Library and ClinicalTrials.gov. Study selection and data extraction were performed by two reviewers independently. Randomised controlled trials and non-randomised studies of interventions reporting effects of selective oestrogen receptor modulators and/or aromatase inhibitors on semen parameters or fertility in men with low testosterone with low/normal gonadotrophins were selected. The risk of bias was assessed using ROB-2 and ROBINS-I tools. The results of randomised controlled trials were summarised using vote counting while summarising effect estimates where available. Non-randomised studies of intervention meta-analysis were conducted using the random-effect model. The certainty of evidence was assessed using GRADE. RESULTS: Five non-randomised studies of interventions (n = 105) of selective oestrogen receptor modulators showed an increase in sperm concentration (pooled mean difference 6.64 million/mL; 95% confidence interval 1.54, 11.74, I2  = 0%) and three non-randomised studies of interventions (n = 83) of selective oestrogen receptor modulators showed an increase in total motile sperm count (pooled mean difference 10.52; 95% confidence interval 1.46-19.59, I2  = 0%), with very low certainty of evidence. The mean body mass index of participants was >30 kg/m2 . Four randomised controlled trials (n = 591) comparing selective oestrogen receptor modulators to placebo showed a heterogeneous effect on sperm concentration. Three included men with overweight or obesity. The results were of very low certainty of evidence. Limited pregnancy or live birth data were available. No studies comparing aromatase inhibitors with placebo or testosterone were found. DISCUSSION AND CONCLUSION: Current studies are of limited size and quality but suggest that selective oestrogen receptor modulators may improve semen parameters in those patients, particularly when associated with obesity.

Aromatase enzyme: Paving the way for exploring aromatization for cardio-renal protection.

Documented male-female differences in the risk of cardiovascular and chronic kidney diseases have been largely attributed to estrogens. The cardiovascular and renal protective effects of estrogens are mediated via the activation of estrogen receptors (ERα and ERß) and G protein-coupled estrogen receptor, and involve interactions with the renin-angiotensin-aldosterone system. Aromatase, also called estrogen synthase, is a cytochrome P-450 enzyme that plays a pivotal role in the conversion of androgens into estrogens. Estrogens are biosynthesized in gonadal and extra-gonadal sites by the action of aromatase. Evidence suggests that aromatase inhibitors, which are used to treat high estrogen-related pathologies, are associated with the development of cardiovascular events. We review the potential role of aromatization in providing cardio-renal protection and highlight several meta-analysis studies on cardiovascular events associated with aromatase inhibitors. Overall, we present the potential of aromatase enzyme as a fundamental contributor to cardio-renal protection.

Effects of dietary aromatase inhibitors on masculinization of rosy barb (Pethia conchonius): Evidence from growth, coloration and gonado-physiological changes.

The objective of this study was to reveal the growth, colouration and gonado-physiological changes due to the exogenous aromatase inhibitor (AIs) in an ornamental fish. 17α-methyltestosterone (MT) and letrozole (LET) were used as potential AIs. The AI were supplemented with a gel-based feed (LET: 50, 100, 150 and MT: 12.5, 25, 37.5 mg/kg feed) in Rosy barb, Pethia conchonius fry. The fishes were reared in a 45-L glass tank using AI treated gel-based feed for 3 months. Growth in AI-based diets was reduced but the reduction was minimal compared to the control. At 25 mg/kg feed of 17 MT, the highest male proportion (84.72% 6.05%) was recorded, which was significantly higher (P≤0.05) than other groups. L*, a*, and b* values showed that 17α-MT-fed groups had brighter coloration (P≤0.05). Histological sections showed that LET-17α-MT suppressed ovarian development, causing atretic oocytes. Testicular development was unaffected. 25 mg/kg-treated feed increased SOD, CAT, GST, and GPX. The AI (MT) at 25 mg/kg gel-based feed could therefore be utilised for musculinization without impacting growth, colour, and antioxidant activity of rosy barb, which serves the entire male population in the ornamental fish sector.

In-silico and in-vitro study reveals ziprasidone as a potential aromatase inhibitor against breast carcinoma.

Aromatase enzyme plays a fundamental role in the development of estrogen receptors, and due to this functionality, the enzyme has gained significant attention as a therapeutic for reproductive disorders and cancer diseases. The currently employed aromatase inhibitors have severe side effects whereas our novel aromatase inhibitor is more selective and less toxic, therefore has greater potential to be developed as a drug. The research framework of this study is to identify a potent inhibitor for the aromatase target by profiling molecular descriptors of the ligand and to find a functional pocket in the target by docking and MD simulations. For assessing cellular and metabolic activities as indicators of cell viability and cytotoxicity, in-vitro studies were performed by using the colorimetric MTT assay. Aromatase activities were determined by a fluorometric method. Cell morphology was assessed by phase-contrast light microscopy. Flow cytometry and Annexin V-FITC/PI staining assay determined cell cycle distribution and apoptosis. This study reports that CHEMBL708 (Ziprasidone) is the most promising compound that showed excellent aromatase inhibitory activity. By using better drug design methods and experimental studies, our study identified a novel compound that could be effective as a high-potential drug candidate against aromatase enzyme. We conclude that the compound ziprasidone effectively blocks the cell cycle at the G1-S phase and induces cancer cell death. Further, in-vivo studies are vital for developing ziprasidone as an anticancer agent. Lastly, our research outcomes based on the results of the in-silico experiments may pave the way for identifying effective drug candidates for therapeutic use in breast cancer.

Unraveling Vulnerabilities in Endocrine Therapy-Resistant HER2+/ER+ Breast Cancer.

Breast tumors overexpressing human epidermal growth factor receptor (HER2) confer intrinsic resistance to endocrine therapy (ET), and patients with HER2/estrogen receptor-positive (HER2+/ER+) breast cancer (BCa) are less responsive to ET than HER2-/ER+. However, real-world evidence reveals that a large subset of patients with HER2+/ER+ receive ET as monotherapy, positioning this treatment pattern as a clinical challenge. In the present study, we developed and characterized 2 in vitro models of ET-resistant (ETR) HER2+/ER+ BCa to identify possible therapeutic vulnerabilities. To mimic ETR to aromatase inhibitors (AIs), we developed 2 long-term estrogen deprivation (LTED) cell lines from BT-474 (BT474) and MDA-MB-361 (MM361). Growth assays, PAM50 subtyping, and genomic and transcriptomic analyses, followed by validation and functional studies, were used to identify targetable differences between ET-responsive parental and ETR-LTED HER2+/ER+ cells. Compared to their parental cells, MM361 LTEDs grew faster, lost ER, and increased HER2 expression, whereas BT474 LTEDs grew slower and maintained ER and HER2 expression. Both LTED variants had reduced responsiveness to fulvestrant. Whole-genome sequencing of aggressive MM361 LTEDs identified mutations in genes encoding transcription factors and chromatin modifiers. Single-cell RNA sequencing demonstrated a shift towards non-luminal phenotypes, and revealed metabolic remodeling of MM361 LTEDs, with upregulated lipid metabolism and ferroptosis-associated antioxidant genes, including GPX4. Combining a GPX4 inhibitor with anti-HER2 agents induced significant cell death in both MM361 and BT474 LTEDs. The BT474 and MM361 AI-resistant models capture distinct phenotypes of HER2+/ER+ BCa and identify altered lipid metabolism and ferroptosis remodeling as vulnerabilities of this type of ETR BCa.

Repurposing of approved drugs for targeting CDK4/6 and aromatase protein using molecular docking and molecular dynamics studies.

Breast cancer is a leading cause of cancer-related morbidity and mortality worldwide, with the highest incidence among women. Among the various subtypes of breast cancer, estrogen-receptor positive (ER+) is the most diagnosed. Estrogen upregulates cyclin D1, which in turn promotes the activity of CDK4/6 and facilitates cell cycle progression. To address this, the first-line treatment for ER+ breast cancer focuses on inhibiting estrogen production by targeting aromatase, the enzyme responsible for the rate-limiting step in estrogen synthesis. Thus, combining CDK4/6 inhibitors with aromatase inhibitors has emerged as a crucial treatment strategy for this type of breast cancer. This approach effectively suppresses estrogen biosynthesis and controls uncontrolled cell proliferation, significantly improving overall survival rates and delayed disease progression. This study aimed to identify compounds that are likely to inhibit CDK4/6 and aromatase simultaneously by using a structure-based drug design strategy. 12,432 approved and investigational drugs were prepared and docked into the active site of CDK6 using HTVS and XP docking modes of Glide resulting in 277 compounds with docking scores ≤ -7 kcal/mol. These compounds were docked into aromatase enzyme using XP mode to give seven drugs with docking scores≤ -6.001 kcal/mol. Furthermore, the shortlisted drugs were docked against CDK4 showing docking scores ranging from -3.254 to -8.254 kcal/mol. Moreover, MM-GBSA for the top seven drugs was calculated. Four drugs, namely ellagic acid, carazolol, dantron, and apomorphine, demonstrated good binding affinity to all three protein targets CDK4/6 and aromatase. Specifically, they exhibited favourable binding free energy with CDK6, with values of -51.92, -53.90, -50.22, and -60.97 kcal/mol, respectively. Among these drugs, apomorphine displayed the most favourable binding free energy with all three protein targets. To further evaluate the stability of the interaction, apomorphine was subjected to a 100 ns molecular dynamics simulation with CDK6. The results indicated the formation of a stable ligand-protein complex. While the results obtained from the MM-GBSA calculation of the binding free energies of the MD conformations of apomorphine showed less favourable binding free energy compared to that obtained post-docking. All these computational findings will provide better structural insight for the development of CDK4/6 and aromatase multi-target inhibitors.

Overexpression of BQ323636.1 contributes to anastrozole resistance in AR+ve/ER+ve breast cancer.

Aromatase inhibitors (Ais) are used as adjuvant endocrine therapy for oestrogen receptor-positive (ER+ve) post-menopausal breast cancer patients. Ais, by inhibiting the enzyme aromatase, block the conversion of androgen to oestrogen, reducing oestrogen levels. Resistance to Ais limits their clinical utilisation. Here, we show that overexpression of BQ323636.1 (BQ), a novel splice variant of nuclear co-repressor NCOR2, is associated with resistance to the non-steroidal aromatase inhibitor anastrozole in ER+ve post-menopausal breast cancer. Mechanistic study indicates that BQ overexpression enhances androgen receptor (AR) activity and in the presence of anastrozole, causes hyper-activation of AR signalling, which unexpectedly enhanced cell proliferation, through increased expression of CDK2, CDK4, and CCNE1. BQ overexpression reverses the effect of anastrozole in ER+ve breast cancer in an AR-dependent manner, whilst co-treatment with the AR antagonist bicalutamide recovered its therapeutic effect both in vitro and in vivo. Thus, for BQ-overexpressing breast cancer, targeting AR can combat anastrozole resistance. Clinical study of 268 primary breast cancer samples of ER+ve patients who had been treated with non-steroidal Ais showed 32.5% (38/117) of cases with combined high nuclear expression of BQ and AR, which were found to be significantly associated with Ai resistance. Non-steroidal Ai-treated patients with high nuclear expression of both BQ and AR had poorer overall, disease-specific, and disease-free survival. These findings suggest the importance of assessing BQ and AR expression status in the primary ER+ve breast tumour prior to Ai treatment. This may save patients from inappropriate treatment and enable effective therapy to be given at an early stage. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

SERPINA3-ANKRD11-HDAC3 pathway induced aromatase inhibitor resistance in breast cancer can be reversed by HDAC3 inhibition.

Endocrine resistance is a major challenge for breast cancer therapy. To identify the genes pivotal for endocrine-resistance progression, we screened five datasets and found 7 commonly dysregulated genes in endocrine-resistant breast cancer cells. Here we show that downregulation of serine protease inhibitor clade A member 3 (SERPINA3) which is a direct target gene of estrogen receptor α contributes to aromatase inhibitor resistance. Ankyrin repeat domain containing 11 (ANKRD11) works as a downstream effector of SERPINA3 in mediating endocrine-resistance. It induces aromatase inhibitor insensitivity by interacting with histone deacetylase 3 (HDAC3) and upregulating its activity. Our study suggests that aromatase inhibitor therapy downregulates SERPINA3 and leads to the ensuing upregulation of ANKRD11, which in turn promotes aromatase inhibitor resistance via binding to and activating HDAC3. HDAC3 inhibition may reverse the aromatase inhibitor resistance in ER-positive breast cancer with decreased SERPINA3 and increased ANKRD11 expression.

In Vitro Effects of Combining Genistein with Aromatase Inhibitors: Concerns Regarding Its Consumption during Breast Cancer Treatment.

INTRODUCTION: The third-generation of aromatase inhibitors (AIs)-Exemestane (Exe), Letrozole (Let), and Anastrozole (Ana)-is the main therapeutic approach applied for estrogen receptor-positive (ER+) breast cancer (BC), the most common neoplasm in women worldwide. Despite their success, the development of resistance limits their efficacy. Genistein (G), a phytoestrogen present in soybean, has promising anticancer properties in ER+ BC cells, even when combined with anticancer drugs. Thus, the potential beneficial effects of combining G with AIs were investigated in sensitive (MCF7-aro) and resistant (LTEDaro) BC cells. METHODS: The effects on cell proliferation and expression of aromatase, ERα/ERß, and AR receptors were evaluated. RESULTS: Unlike the combination of G with Ana or Let, which negatively affects the Ais' therapeutic efficacy, G enhanced the anticancer properties of the steroidal AI Exe, increasing the antiproliferative effect and apoptosis relative to Exe. The hormone targets studied were not affected by this combination when compared with Exe. CONCLUSIONS: This is the first in vitro study that highlights the potential benefit of G as an adjuvant therapy with Exe, emphasizing, however, that soy derivatives widely used in the diet or applied as auxiliary medicines may increase the risk of adverse interactions with nonsteroidal AIs used in therapy.

Real-World Tumor Response of Palbociclib in Combination With an Aromatase Inhibitor as First-Line Therapy in Pre/Perimenopausal Women With Metastatic Breast Cancer.

BACKGROUND: Limited real-world data exist regarding the efficacy of palbociclib in combination with endocrine therapy in pre/perimenopausal women with metastatic breast cancer. OBJECTIVE: We aimed to compare real-world tumor responses among pre/perimenopausal women who initiated palbociclib plus an aromatase inhibitor (AI) or AI monotherapy as first-line treatment for hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer. METHODS: This retrospective observational cohort study (NCT05012644) used electronic health record data from The US Oncology Network. Tumor responses were determined based on treating clinicians' assessments of radiologic evidence for changes in disease burden. Normalized inverse probability treatment weighting was used to balance baseline characteristics between treatment cohorts. RESULTS: Of 196 pre/perimenopausal women, 116 and 80 were in the palbociclib plus AI cohort and AI cohort, respectively. Real-world response rates (complete or partial response) were 52.1% and 46.2%, respectively (odds ratio, 1.27 [95% confidence interval 0.72‒2.24]). Among patients with one or more tumor assessments on treatment, real-world response rates were 60.0% in the palbociclib plus AI cohort (n = 103) and 49.9% in the AI cohort (n = 71; odds ratio, 1.51 [95% confidence interval 0.82‒2.77]). CONCLUSIONS: This real-world analysis suggests that pre/perimenopausal patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer appear more likely to respond to palbociclib plus AI versus AI alone as first-line therapy, which may support the combination as a standard-of-care treatment for this patient population.

Palbociclib (Ibrance^®) is a medicine for patients with metastatic breast cancer (MBC). Metastatic means that the cancer has spread to other places in the body. Patients take palbociclib with hormone therapy, such as an aromatase inhibitor (AI). Palbociclib plus an AI is a treatment for a type of MBC called HR+/HER2‒ MBC. HR+/HER2‒ stands for hormone receptor positive, human epidermal growth factor receptor 2 negative. Researchers wanted to observe responses to treatment in routine clinical practice among women with HR+/HER2­ MBC who had not reached menopause. A response is if a tumor shrinks or disappears after treatment. This study used healthcare information reported in electronic medical records of patients seen by doctors in The US Oncology Network. This study included 196 women with HR+/HER2­ MBC who had not reached menopause and had not received prior treatment for MBC. A total of 116 women received palbociclib plus an AI, and 80 women received an AI alone. Researchers used standard statistical approaches to balance baseline characteristics between the two treatment groups. These adjustments made the groups more similar so that researchers could compare treatment responses. Sixty percent of patients who took palbociclib plus an AI responded, compared with 50% of patients who took an AI alone. These results suggest that palbociclib plus an AI may benefit women with HR+/HER2‒ MBC who have not reached menopause.