Effect of aromatase inhibition on functional gene modules in estrogen receptor-positive breast cancer and their relationship with antiproliferative response

Tumor Infiltrating Lymphocytes across Breast Cancer Subtypes: Current Issues for Biomarker Assessment

Tumor-infiltrating lymphocytes (TILs) represent a surrogate biomarker of anti-tumor, lymphocyte-mediated immunity. In early, triple-negative breast cancer, TILs have level 1B of evidence to predict clinical outcomes. TILs represent a promising biomarker to select patients who can experience a better prognosis with de-intensified cancer treatments and derive larger benefits from immune checkpoint inhibitors. However, the assessment and the validation of TILs as a biomarker require a prospective and rigorous demonstration of its clinical validity and utility, provided reproducible analytical performance. With pending data about the prospective validation of TILs' clinical validity to modulate treatments in early breast cancer, this review summarizes the most important current issues and future challenges related to the implementation of TILs assessments across all breast cancer subtypes and their potential integration into clinical practice.

Pathogenic role of 25-hydroxycholesterol in cancer development and progression

Cholesterol is an essential lipid that serves several important functions, including maintaining the homeostasis of cells, acting as a precursor to bile acid and steroid hormones and preserving the stability of membrane lipid rafts. 25-hydroxycholesterol (25-HC) is a cholesterol derivative that may be formed from cholesterol. 25-HC is a crucial component in various biological activities, including cholesterol metabolism. In recent years, growing evidence has shown that 25-HC performs a critical function in the etiology of cancer, infectious diseases and autoimmune disorders. This review will summarize the latest findings regarding 25-HC, including its biogenesis, immunomodulatory properties and role in innate/adaptive immunity, inflammation and the development of various types of cancer.

Association Between Different Domains of Physical Activity and Body Adiposity Indicators in Breast Cancer Survivors

BACKGROUND

To analyze the relationship between different physical activity (PA) domains and adiposity indicators in breast cancer survivors.

METHODS

This is a cross-sectional study, composed of 115 breast cancer (BC) survivors. Measurements of weight, height, waist circumference (WC), and hip circumference were objectively collected, as well as the analysis of body fat percentage through bioelectrical impedance analysis. The PA level was assessed by the Baecke questionnaire including domains related to occupational activity, leisure-time activity, and transportation, while the time spent in sedentary behavior was assessed through self-reported screen-time. Socioeconomic status was assessed through the Brazilian criteria for economic classification and considered as a covariate.

RESULTS

BC survivors with higher PA levels in leisure-time activity/sport presented reductions in body fat percentage (β = 1.13%; CI = -2.06; -0.21), BMI (β = 0.80 kg/m²; CI = -1.50; -0.11), WC (β = 1.89 cm; CI = -3.54; -0.23), and waist-to-height ratio (β = 0.13 cm; CI = -0.23; -0.02). Similar values were observed in PA during transportation and in total. There was no correlation between PA at work and adiposity indicators.

CONCLUSION

Different PA domains were inversely related to body adiposity in BC survivors.

IHC-based Ki67 as response biomarker to tamoxifen in breast cancer window trials enrolling premenopausal women

Window studies are gaining traction to assess (molecular) changes in short timeframes. Decreased tumor cell positivity for the proliferation marker Ki67 is often used as a proxy for treatment response. Immunohistochemistry (IHC)-based Ki67 on tissue from neo-adjuvant trials was previously reported to be predictive for long-term response to endocrine therapy for breast cancer in postmenopausal women, but none of these trials enrolled premenopausal women. Nonetheless, the marker is being used on this subpopulation. We compared pathologist assessed IHC-based Ki67 in samples from pre- and postmenopausal women in a neo-adjuvant, endocrine therapy focused trial (NCT00738777), randomized between tamoxifen, anastrozole, or fulvestrant. These results were compared with (1) IHC-based Ki67 scoring by AI, (2) mitotic figures, (3) mRNA-based Ki67, (4) five independent gene expression signatures capturing proliferation, and (5) blood levels for tamoxifen and its metabolites as well as estradiol. Upon tamoxifen, IHC-based Ki67 levels were decreased in both pre- and postmenopausal breast cancer patients, which was confirmed using mRNA-based cell proliferation markers. The magnitude of decrease of Ki67 IHC was smaller in pre- versus postmenopausal women. We found a direct relationship between post-treatment estradiol levels and the magnitude of the Ki67 decrease in tumors. These data suggest IHC-based Ki67 may be an appropriate biomarker for tamoxifen response in premenopausal breast cancer patients, but anti-proliferative effect size depends on estradiol levels.

Oestrogen deprivation induces chemokine production and immune cell recruitment in in vitro and in vivo models of oestrogen receptor-positive breast cancer

Background

Oestrogen receptor-positive (ER+) breast cancer is commonly treated using endocrine therapies such as aromatase inhibitors which block synthesis of oestradiol, but the influence of this therapy on the immune composition of breast tumours has not been fully explored. Previous findings suggest that tumour infiltrating lymphocytes and immune-related gene expression may be altered by treatment with aromatase inhibitors. However, whether these changes are a direct result of impacts on the host immune system or mediated through tumour cells is not known. We aimed to investigate the effect of oestrogen deprivation on the expression of chemokines and immune infiltration in vitro and in an ER+ immunocompetent mouse model.

Methods

RT-qPCR and a bead-based Bioplex system were used to investigate the expression of chemokines in MCF-7 breast cancer cells deprived of oestrogen. A migration assay and flow cytometry were used to measure the migration of human peripheral blood mononuclear cells (PBMCs) to MCF-7 cells grown without the main biologically active oestrogen, oestradiol. Using flow cytometry and immunohistochemistry, we examined the immune cell infiltrate into tumours created by injecting SSM3 ER+ breast cancer cells into wild-type, immunocompetent 129/SvEv mice.

Results

This study demonstrates that oestrogen deprivation increases breast cancer secretion of TNF, CCL5, IL-6, IL-8, and CCL22 and alters total human peripheral blood mononuclear cell migration in an in vitro assay. Oestrogen deprivation of breast cancer cells increases migration of CD4+ T cells and decreases migration of CD11c+ and CD14+ PBMC towards cancer cells. PBMC migration towards breast cancer cells can be reduced by treatment with the non-steroidal anti-inflammatory drugs, aspirin and celecoxib. Treatment with endocrine therapy using the aromatase inhibitor letrozole increases CD4+ T cell infiltration into ER+ breast cancer tumours in immune competent mice.

Conclusions

These results suggest that anti-oestrogen treatment of ER+ breast cancer cells can alter cytokine production and immune cells in the area surrounding the cancer cells. These findings may have implications for the combination and timing of anti-oestrogen therapies with other therapies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01472-1.

Endogenous and Therapeutic Estrogens: Maestro Conductors of the Microenvironment of ER+ Breast Cancers

Estrogen receptor alpha (ERα) marks heterogeneous breast cancers which display a repertoire of somatic genomic mutations and an immune environment that differs from other breast cancer subtypes. These cancers also exhibit distinct biological behaviors; despite an overall better prognosis than HER2+ or triple negative breast cancers, disseminated dormant cells can lead to disease recurrence decades after the initial diagnosis and treatment. Estrogen is the best studied driver of these cancers, and antagonism or reduction of estrogen activity is the cornerstone of therapeutic approaches. In addition to reducing proliferation of ERα+ cancer cells, these treatments also alter signals to multiple other target cells in the environment, including immune cell subpopulations, cancer-associated fibroblasts, and endothelial cells via several distinct estrogen receptors. In this review, we update progress in our understanding of the stromal cells populating the microenvironments of primary and metastatic ER+ tumors, the effects of estrogen on tumor and stromal cells to modulate immune activity and the extracellular matrix, and net outcomes in experimental and clinical studies. We highlight new approaches that will illuminate the unique biology of these cancers, provide the foundation for developing new treatment and prevention strategies, and reduce mortality of this disease.

Prognostic Relevance of Neutrophil to Lymphocyte Ratio (NLR) in Luminal Breast Cancer: A Retrospective Analysis in the Neoadjuvant Setting

The neutrophil to lymphocyte ratio (NLR) is a promising predictive and prognostic factor in breast cancer. We investigated its ability to predict disease-free survival (DFS) and overall survival (OS) in patients with luminal A- or luminal B-HER2-negative breast cancer who received neoadjuvant chemotherapy (NACT). Pre-treatment complete blood cell counts from 168 consecutive patients with luminal breast cancer were evaluated to assess NLR. The study population was stratified into NLR^low or NLR^high according to a cut-off value established by receiving operator curve (ROC) analysis. Data on additional pre- and post-treatment clinical-pathological characteristics were also collected. Kaplan–Meier curves, log-rank tests, and Cox proportional hazards models were used for statistical analyses. Patients with pre-treatment NLR^low showed a significantly shorter DFS (HR: 6.97, 95% CI: 1.65–10.55, p = 0.002) and OS (HR: 7.79, 95% CI: 1.25–15.07, p = 0.021) compared to those with NLR^high. Non-ductal histology, luminal B subtype, and post-treatment Ki67 ≥ 14% were also associated with worse DFS (p = 0.016, p = 0.002, and p = 0.001, respectively). In a multivariate analysis, luminal B subtype, post-treatment Ki67 ≥ 14%, and NLR^low remained independent prognostic factors for DFS, while only post-treatment Ki67 ≥ 14% and NLR^low affected OS. The present study provides evidence that pre-treatment NLR^low helps identify women at higher risk of recurrence and death among patients affected by luminal breast cancer treated with NACT.

The immunomodulatory effects of endocrine therapy in breast cancer

Endocrine therapies with SERMs (selective estrogen receptor modulators) or SERDs (selective estrogen receptor downregulators) are standard therapies for patients with estrogen receptor (ER)-positive breast cancer. Multiple small molecule inhibitors targeting the PI3K-AKT-mTOR pathway or CDK4/6 have been developed to be used in combination with anti-estrogen drugs to overcome endocrine resistance. In addition to their direct antitumor effects, accumulating evidence has revealed the tumor immune microenvironment (TIM)-modulating effects of these therapeutic strategies, which have not been properly acknowledged previously. The immune microenvironment of breast tumors plays a crucial role in tumor development, metastasis and treatment response to endocrine therapy and immunotherapy. Therefore, in our current work, we comprehensively review the immunomodulatory effect of endocrine therapy and discuss its potential applications in combination with immune checkpoint inhibitors in breast cancer treatment.

PLK1 inhibition exhibits strong anti-tumoral activity in CCND1-driven breast cancer metastases with acquired palbociclib resistance

A significant proportion of patients with oestrogen receptor (ER) positive breast cancers (BC) develop resistance to endocrine treatments (ET) and relapse with metastatic disease. Here we perform whole exome sequencing and gene expression analysis of matched primary breast tumours and bone metastasis-derived patient-derived xenografts (PDX). Transcriptomic analyses reveal enrichment of the G2/M checkpoint and up-regulation of Polo-like kinase 1 (PLK1) in PDX. PLK1 inhibition results in tumour shrinkage in highly proliferating CCND1-driven PDX, including different RB-positive PDX with acquired palbociclib resistance. Mechanistic studies in endocrine resistant cell lines, suggest an ER-independent function of PLK1 in regulating cell proliferation. Finally, in two independent clinical cohorts of ER positive BC, we find a strong association between high expression of PLK1 and a shorter metastases-free survival and poor response to anastrozole. In conclusion, our findings support clinical development of PLK1 inhibitors in patients with advanced CCND1-driven BC, including patients progressing on palbociclib treatment.

Tumor-infiltrating lymphocytes (TILs) in ER+/HER2- breast cancer

PURPOSE

The prognostic role of tumor-infiltrating lymphocytes (TILs) in ER+/HER2- breast cancer (BC) is debated. We evaluated the association of TILs and clinico-pathological features with distant disease-free survival (DDFS) in patients with ER+/HER2- BC treated at a single institution.

PATIENTS AND METHODS

A mono-institutional case-cohort series of 987 patients with early ER+/HER2- BC was retrospectively analyzed. TILs were considered both as continuous variable, and dichotomized in low (< 5%) vs high (≥ 5%). The main outcome was DDFS. Median follow-up was 7.5 years (0.1-10). Univariate and multivariable Cox proportional hazards regression with inverse sub-cohort sampling probability weighting were used to evaluate the risk across groups.

RESULTS

Median TIL count was 2% (Q1-Q3 1-4%). Higher TILs were positively associated with number of lymph nodes involved (p = 0.003), tumor grade (p < 0.0001), peritumoral vascular invasion (p = 0.003), higher Ki-67 (p = 0.0001), luminal B subtype (p < 0.0001), and chemotherapy use (p < 0.00019). In multivariable regression analysis, only higher Ki-67 expression retained significant association with TILs. At univariate Cox regression analysis, TIL expression (≥ 5% vs. < 5%) was not associated with DDFS (HR 1.08, 95% CI 0.80-1.46, p = 0.62). In patients treated with adjuvant chemotherapy, high TILs were associated with better DDFS (HR 0.52, 95%CI 0.33-0.83, p = 0.006), particularly in the group with Ki-67 ≥ 20% (HR 0.50, 95%CI 0.29-0.86, p = 0.01).

CONCLUSION

High TILs in ER+/HER2- BC are significantly associated with clinico-pathological features of dismal outcome. TIL prognostic value seems different in patients treated with or without chemotherapy. Our findings suggest that the high-risk subgroup might be more immunogenic, thus deserving the exploration of immunotherapy approaches.

Tumour kinome re-wiring governs resistance to palbociclib in oestrogen receptor positive breast cancers, highlighting new therapeutic modalities

Combination of CDK4/6 inhibitors and endocrine therapy improves clinical outcome in advanced oestrogen receptor (ER)-positive breast cancer, however relapse is inevitable. Here, we show in model systems that other than loss of RB1 few gene-copy number (CN) alterations are associated with irreversible-resistance to endocrine therapy and subsequent secondary resistance to palbociclib. Resistance to palbociclib occurred as a result of tumour cell re-wiring leading to increased expression of EGFR, MAPK, CDK4, CDK2, CDK7, CCNE1 and CCNE2. Resistance altered the ER genome wide-binding pattern, leading to decreased expression of ‘classical’ oestrogen-regulated genes and was accompanied by reduced sensitivity to fulvestrant and tamoxifen. Persistent CDK4 blockade decreased phosphorylation of tuberous sclerosis complex 2 (TSC2) enhancing EGFR signalling, leading to the re-wiring of ER. Kinome-knockdown confirmed dependency on ERBB-signalling and G2/M–checkpoint proteins such as WEE1, together with the cell cycle master regulator, CDK7. Noteworthy, sensitivity to CDK7 inhibition was associated with loss of ER and RB1 CN. Overall, we show that resistance to CDK4/6 inhibitors is dependent on kinase re-wiring and the redeployment of signalling cascades previously associated with endocrine resistance and highlights new therapeutic networks that can be exploited upon relapse after CDK4/6 inhibition.

Impact of aromatase inhibitor treatment on global gene expression and its association with antiproliferative response in ER+ breast cancer in postmenopausal patients

Background

Endocrine therapy reduces breast cancer mortality by 40%, but resistance remains a major clinical problem. In this study, we sought to investigate the impact of aromatase inhibitor (AI) therapy on gene expression and identify gene modules representing key biological pathways that relate to early AI therapy resistance.

Methods

Global gene expression was measured on pairs of core-cut biopsies taken at baseline and at surgery from 254 patients with ER-positive primary breast cancer randomised to receive 2-week presurgical AI (n = 198) or no presurgical treatment (control n = 56) from the POETIC trial. Data from the AI group was adjusted to eliminate artefactual process-related changes identified in the control group. The response was assessed by changes in the proliferation marker, Ki67.

Results

High baseline ESR1 expression associated with better AI response in HER2+ tumours but not HER2− tumours. In HER2− tumours, baseline expression of 48 genes associated with poor antiproliferative response (p < 0.005) including PERP and YWHAQ, the two most significant, and the transcription co-regulators (SAP130, HDAC4, and NCOA7) which were among the top 16 most significant. Baseline gene signature scores measuring cell proliferation, growth factor signalling (ERBB2-GS, RET/GDNF-GS, and IGF-1-GS), and immune activity (STAT1-GS) were significantly higher in poor AI responders. Two weeks of AI caused downregulation of genes involved in cell proliferation and ER signalling, as expected. Signature scores of E2F activation and TP53 dysfunction after 2-week AI were associated with poor AI response in both HER2− and HER2+ patients.

Conclusions

There is a high degree of heterogeneity in adaptive mechanisms after as little as 2-week AI therapy; however, all appear to converge on cell cycle regulation. Our data support the evaluation of whether an E2F signatures after short-term exposure to AI may identify those patients most likely to benefit from the early addition of CDK4/6 inhibitors.

Trial registration

ISRCTN, ISRCTN63882543, registered on 18 December 2007.

Human leucocyte antigen class I in hormone receptor-positive, HER2-negative breast cancer: association with response and survival after neoadjuvant chemotherapy

Background

Clinical application of cancer immunotherapy requires a better understanding of tumor immunogenicity and the tumor microenvironment. HLA class I molecules present antigens to CD8⁺ cytotoxic cells. Their loss or downregulation is frequently found in tumors resulting in reduced T cell responses and worse prognosis.

Methods

We evaluated HLA class I heavy chain expression by immunohistochemistry in 863 biopsies (GeparTrio trial). Patients received neoadjuvant chemotherapy and adjuvant endocrine treatment if tumors were hormone receptor-positive (HR+). In parallel, the expression of HLA-A was analyzed using a microarray cohort of 320 breast cancer patients from the MD Anderson Cancer Center. We evaluated its association with clinical outcome, tumor-infiltrating lymphocytes (TILs), and immune cell metagenes.

Results

In HR+/HER2− breast cancer, HLA class I heavy chain expression was associated with increased TILs and better response to chemotherapy (7% vs. 14% pCR rate, P = 0.029), but worse disease-free survival (hazard ratio (HR) 1.6 (1.1–2.4); P = 0.024). The effect was significant in a multivariate model adjusted for clinical and pathological variables (HR 1.7 (1.1–2.6); P = 0.016) and was confirmed by analysis of HLA-A in a microarray cohort. HLA-A was correlated to most immune cell metagenes. There was no association with response or survival in triple-negative or HER2+ disease.

Conclusions

The study confirms the negative prognostic role of lymphocytes in HR+ breast cancer and points at a complex interaction between chemotherapy, endocrine treatment, and tumor immunogenicity. The results point at a subtype-specific and potentially treatment-specific role of tumor-immunological processes in breast cancer with different implications in triple-negative and hormone receptor-positive disease.

IF, Vanderlei LCM. Changes in Cardiac Autonomic Modulation in Women with Breast Cancer Using Aromatase Inhibitors and the Relation with Biochemical Variables

BACKGROUND

The use of autonomic modulation as a predictor of cardiovascular risk in women with breast cancer is important.

OBJECTIVE

To evaluate the cardiac autonomic modulation of postmenopausal women using aromatase inhibitors for breast cancer treatment, as well as its relation with the following biochemical variables.

METHODS

Postmenopausal women who did not have breast cancer (n = 33) and postmenopausal women with breast cancer (n = 15). For evaluation of the autonomic modulation the heart rate was recorded beat-to-beat for 30 minutes and the series of RR intervals obtained were used to calculate the following heart rate variability indices: Mean RR ms, SDNN (standard deviation of all normal RR intervals, expressed in milliseconds) ms, Mean HR, RMSSD (square root of the mean of the squared differences between adjacent normal RR interval) ms, NN50 (number of pairs of successive NNs that differ by more than 50 ms) count, pNN50% (proportion of NN50 divided by total number of NNs), RRtri (RR triangular), TINN (triangular interpolation of NN interval) ms, SD1 ms, SD2 ms, LF ms2, HF ms2, LH/HF ms2. The values of biochemical variables (fasting glycemia, triglycerides, HDL-cholesterol, and C-reactive protein) were analyzed by blood sample.

RESULTS

Lower values of heart rate variability indices were observed in postmenopausal women with breast cancer in relation to postmenopausal women who did not have breast cancer: Mean RR (p = 0.03); SDNN (p = 0.03); RMSSD (p = 0.03); NN50 count (p = 0.03); pNN50 % (p = 0.03); RRtri (p = 0.02); SD1 (p = 0.01); SD2 (p = 0.02); LF ms2 (p = 0.01); HF ms2 (p = 0.03).There was an inversely proportional correlation between the indices SDNN, SD2, and HFms2 with triglycerides (SDNN p = 0.04; SD2 p = 0.04; HF ms2 p = 0.04). No statistically significant correlations were found between heart rate variability indices and others variables. Statistical significance was set at 5% for all analyses.

CONCLUSION

Women with breast cancer present reduced autonomic modulation and in these women of heart rate variability indices are inversely correlated with triglyceride values.

Exploration of tumour-infiltrating lymphocytes as a predictive biomarker for adjuvant endocrine therapy in early breast cancer

PURPOSE

Tumour-infiltrating lymphocytes (TILs) have been shown to be prognostic for disease-free survival and predictive for the benefit of chemotherapy in patients with early breast cancer, but have not been studied for endocrine therapy.

EXPERIMENTAL DESIGN

The number of CD8-positive TILs was assessed in a subcohort of 236 patients in the Intergroup Exemestane Study. AQ After 2-3 years of adjuvant tamoxifen, AQpatients were randomized between the schemes of continuation for 5 years on tamoxifen and switching to exemestane. The numbers of CD8-positive TILs were analysed for correlations with disease-free survival (DFS) and overall survival (OS). A similar analysis was performed on 2596 patients in the TEAM trial who were randomized between the sequential scheme and the exemestane monotherapy.

RESULTS

In the first cohort, patients with low (below median) numbers of CD8-positive TILs had a univariate hazard ratio (HR) for DFS of 0.27 (95% CI 0.13-0.55) in favour of treatment with exemestane, whereas this benefit was not observed in patients with high numbers of CD8-positive TILs (HR 1.34, 95% CI 0.71-2.50, HR for interaction 5.02, p = 0.001). In the second cohort, patients with low numbers of CD8-positive TILs showed a benefit of exemestane treatment on recurrence-free survival (RFS HR 0.67, 95% CI 0.45-0.99), and not with above-median numbers of CD8-positive TILs (HR 0.86, 95% CI 0.59-1.26, HR for interaction 1.29, p = 0.36).

CONCLUSIONS

This study is the first to propose the number of CD8-positive TILs as potential predictive markers for endocrine therapy, with the low presence of CD8-positive TILs associated to benefit for exemestane-inclusive therapy. However, treatment-by-marker interactions were only significant in one cohort, indicating the need for further validation.

Relevance of Spatial Heterogeneity of Immune Infiltration for Predicting Risk of Recurrence After Endocrine Therapy of ER+ Breast Cancer

Background

Despite increasing evidence supporting the clinical utility of immune infiltration in the estrogen receptor-negative (ER-) subtype, the prognostic value of immune infiltration for ER+ disease is not well defined.

Methods

Quantitative immune scores of cell abundance and spatial heterogeneity were computed using a fully automated hematoxylin and eosin-stained image analysis algorithm and spatial statistics for 1178 postmenopausal patients with ER+ breast cancer treated with five years' tamoxifen or anastrozole. The prognostic significance of immune scores was compared with Oncotype DX 21-gene recurrence score (RS), PAM50 risk of recurrence (ROR) score, IHC4, and clinical treatment score, available for 963 patients. Statistical tests were two-sided.

Results

Scores of immune cell abundance were not associated with recurrence-free survival. In contrast, high immune spatial scores indicating increased cell spatial clustering were associated with poor 10-year, early (0-5 years), and late (5-10 years) recurrence-free survival (Immune Hotspot: LR-χ2 = 14.06, P < .001, for 0-10 years; LR-χ2 = 6.24, P = .01, for 0-5 years; LR-χ2 = 7.89, P = .005, for 5-10 years). The prognostic value of spatial scores for late recurrence was similar to that of IHC4 and RS in both populations, but was not as strong as other tests in comparison for recurrence across 10 years.

Conclusions

These results provide a missing link between tumor immunity and disease outcome in ER+ disease by examining tumor spatial architecture. The association between spatial scores and late recurrence suggests a lasting memory of protumor immunity that may impact disease progression and evolution of endocrine treatment resistance, which may be exploited for therapeutic advances.

Neoadjuvant tamoxifen synchronizes ERα binding and gene expression profiles related to outcome and proliferation

Estrogen receptor alpha (ERα)-positive breast cancers are frequently treated with tamoxifen, but resistance is common. It remains elusive how tamoxifen resistance occurs and predictive biomarkers for treatment outcome are needed. Because most biomarker discovery studies are performed using pre-treatment surgical resections, the effects of tamoxifen therapy directly on the tumor cell in vivo remain unexamined. In this study, we assessed DNA copy number, gene expression profiles and ERα/chromatin binding landscapes on breast tumor specimens, both before and after neoadjuvant tamoxifen treatment. We observed neoadjuvant tamoxifen treatment synchronized ERα/chromatin interactions and downstream gene expression, indicating that hormonal therapy reduces inter-tumor molecular variability. ERα-synchronized sites are associated with dynamic FOXA1 action at these sites, which is under control of growth factor signaling. Genes associated with tamoxifen-synchronized sites are capable of differentiating patients for tamoxifen benefit. Due to the direct effects of therapeutics on ERα behavior and transcriptional output, our study highlights the added value of biomarker discovery studies after neoadjuvant drug exposure.

Tumour-infiltrating lymphocytes and prognosis in different subtypes of breast cancer: a pooled analysis of 3771 patients treated with neoadjuvant therapy

BACKGROUND

Tumour-infiltrating lymphocytes (TILs) are predictive for response to neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) and HER2-positive breast cancer, but their role in luminal breast cancer and the effect of TILs on prognosis in all subtypes is less clear. Here, we assessed the relevance of TILs for chemotherapy response and prognosis in patients with TNBC, HER2-positive breast cancer, and luminal-HER2-negative breast cancer.

METHODS

Patients with primary breast cancer who were treated with neoadjuvant combination chemotherapy were included from six randomised trials done by the German Breast Cancer Group. Pretherapeutic core biopsies from 3771 patients included in these studies were assessed for the number of stromal TILs by standardised methods according to the guidelines of the International TIL working group. TILs were analysed both as a continuous parameter and in three predefined groups of low (0-10% immune cells in stromal tissue within the tumour), intermediate (11-59%), and high TILs (≥60%). We used these data in univariable and multivariable statistical models to assess the association between TIL concentration and pathological complete response in all patients, and between the amount of TILs and disease-free survival and overall survival in 2560 patients from five of the six clinical trial cohorts.

FINDINGS

In the luminal-HER2-negative breast cancer subtype, a pathological complete response (pCR) was achieved in 45 (6%) of 759 patients with low TILs, 48 (11%) of 435 with intermediate TILs, and 49 (28%) of 172 with high TILs. In the HER2-positive subtype, pCR was observed in 194 (32%) of 605 patients with low TILs, 198 (39%) of 512 with intermediate TILs, and 127 (48%) of 262 with high TILs. Finally, in the TNBC subtype, pCR was achieved in 80 (31%) of 260 patients with low TILs, 117 (31%) of 373 with intermediate TILs, and 136 (50%) of 273 with high TILs (p<0·0001 for each subtype, χ² test for trend). In the univariable analysis, a 10% increase in TILs was associated with longer disease-free survival in TNBC (hazard ratio [HR] 0·93 [95% CI 0·87-0·98], p=0·011) and HER2-positive breast cancer (0·94 [0·89-0·99], p=0·017), but not in luminal-HER2-negative tumours (1·02 [0·96-1·09], p=0·46). The increase in TILs was also associated with longer overall survival in TNBC (0·92 [0·86-0·99], p=0·032), but had no association in HER2-positive breast cancer (0·94 [0·86-1·02], p=0·11), and was associated with shorter overall survival in luminal-HER2-negative tumours (1·10 [1·02-1·19], p=0·011).

INTERPRETATION

Increased TIL concentration predicted response to neoadjuvant chemotherapy in all molecular subtypes assessed, and was also associated with a survival benefit in HER2-positive breast cancer and TNBC. By contrast, increased TILs were an adverse prognostic factor for survival in luminal-HER2-negative breast cancer, suggesting a different biology of the immunological infiltrate in this subtype. Our data support the hypothesis that breast cancer is immunogenic and might be targetable by immune-modulating therapies. In light of the results in luminal breast cancer, further research investigating the interaction of the immune system with different types of endocrine therapy is warranted.

FUNDING

Deutsche Krebshilfe and European Commission.

Relationship between physical activity practice and metabolic profile of postmenopausal women under treatment with aromatase inhibitors for breast cancer

OBJECTIVE

To analyze the relationship between physical activity practice and metabolic profile of postmenopausal women under treatment with aromatase inhibitors (AIs) for the treatment of breast cancer.

STUDY DESIGN

Cross-sectional study, conducted with 101 postmenopausal women (aged 50-80 years). The sample was divided into two groups; group without cancer (GW; n=65) and breast cancer group treated with AIs (GC; n=36). Physical activity (PA) was evaluated by questionnaire. Correlations between physical activity and metabolic variables were made by Pearson's correlation coefficient and the magnitude of these relationships by linear regression.

RESULTS

In GW, there were observed significant inverse correlations between physical activity and VLDL cholesterol (β=-0.036; 95% CI=-0.068; -0.004); triglycerides (β=-0.036; 95% CI=-0.015; -0.002); glycose (β=-0.029; 95% CI=-0.047; -0.012); and C-reactive protein (β=-0.44; 95% CI=-0.085; -0.003). However, for women under treatment of AIs there was no relationship between physical activity and metabolic variables.

CONCLUSION

The amount of physical activity practice is inversely related to lipid profile, glucose and C-reactive protein in women without breast cancer. This relation was not observed in the cancer survivors, suggesting that the use of aromatase inhibitors could influence or low intensity of physical activity.

Racial disparity in survival from estrogen and progesterone receptor-positive breast cancer: implications for reducing breast cancer mortality disparities

INTRODUCTION

Non-Latina black breast cancer patients experience a shorter survival from breast cancer than their non-Latina white counterparts. We compared breast cancer-specific survival for the subset of black and white patients with estrogen and/or progesterone receptor-positive tumors that are generally targeted with endocrine therapy.

METHODS

Using data collected from a population-based cohort of breast cancer patients from Chicago, IL, Kaplan-Meier survival curves and hazard functions were generated and proportional hazards models were estimated to determine the black/white disparity in time to death from breast cancer while adjusting for age at diagnosis, patient characteristics, treatment-related variables, and tumor grade and stage.

RESULTS

In regression models, hazard of breast cancer death among ER/PR-positive patients was at least 4 times higher for black than for white patients in all models tested. Notably, even after adjusting for stage at diagnosis, tumor grade, and treatment variables (including initiation of systemic adjuvant therapies), the hazard ratio for death from ER/PR-positive breast cancer between black and white women was 4.39 (95% CI 1.76, 10.9, p = 0.001).

CONCLUSIONS

We observed a racial disparity in breast cancer survival for patients diagnosed with ER/PR-positive tumors that did not appear to be due to differences in tumor stage, grade, or therapy initiation in black patients, suggesting that there may be racial differences in the molecular characteristics of hormone receptor-positive tumors, such that ER/PR-positive tumors in black patients may be less responsive to standard treatments.

Presurgical window of opportunity trial design as a platform for testing anticancer drugs: Pros, cons and a focus on breast cancer

The high attrition rate is a major issue in anticancer drug development. Among the alternative trial designs, presurgical window of opportunity trials envision a short course treatment in the time window between diagnostic biopsy and surgery in a moderately-sized patient population. This approach allows testing therapeutics when pre- and post-treatment tumor tissues are available for comprehensive molecular analyses. The emerging evidence may help define the ability of a given agent to modulate its target(s) and help obtain a broader picture of the molecular changes operated by the treatment. The resulting gain may outweigh the potential harms for patients in the early disease setting. Window of opportunity trials have been extensively applied to breast cancer. Overall, a wider use of these trial designs might lead to the identification of potential responders, ineffective drugs or combinations, and ultimately contribute to enhance the efficiency of the clinical developmental process.

Cholesterol biosynthesis pathway as a novel mechanism of resistance to estrogen deprivation in estrogen receptor-positive breast cancer

Background

Therapies targeting estrogenic stimulation in estrogen receptor-positive (ER+) breast cancer (BC) reduce mortality, but resistance remains a major clinical problem. Molecular studies have shown few high-frequency mutations to be associated with endocrine resistance. In contrast, expression profiling of primary ER+ BC samples has identified several promising signatures/networks for targeting.

Methods

To identify common adaptive mechanisms associated with resistance to aromatase inhibitors (AIs), we assessed changes in global gene expression during adaptation to long-term estrogen deprivation (LTED) in a panel of ER+ BC cell lines cultured in 2D on plastic (MCF7, T47D, HCC1428, SUM44 and ZR75.1) or in 3D on collagen (MCF7) to model the stromal compartment. Furthermore, dimethyl labelling followed by LC-MS/MS was used to assess global changes in protein abundance. The role of target genes/proteins on proliferation, ER-mediated transcription and recruitment of ER to target gene promoters was analysed.

Results

The cholesterol biosynthesis pathway was the common upregulated pathway in the ER+ LTED but not the ER– LTED cell lines, suggesting a potential mechanism dependent on continued ER expression. Targeting the individual genes of the cholesterol biosynthesis pathway with siRNAs caused a 30–50 % drop in proliferation. Further analysis showed increased expression of 25-hydroxycholesterol (HC) in the MCF7 LTED cells. Exogenous 25-HC or 27-HC increased ER-mediated transcription and expression of the endogenous estrogen-regulated gene TFF1 in ER+ LTED cells but not in the ER– LTED cells. Additionally, recruitment of the ER and CREB-binding protein (CBP) to the TFF1 and GREB1 promoters was increased upon treatment with 25-HC and 27-HC. In-silico analysis of two independent studies of primary ER+ BC patients treated with neoadjuvant AIs showed that increased expression of MSMO1, EBP, LBR and SQLE enzymes, required for cholesterol synthesis and increased in our in-vitro models, was significantly associated with poor response to endocrine therapy.

Conclusion

Taken together, these data provide support for the role of cholesterol biosynthesis enzymes and the cholesterol metabolites, 25-HC and 27-HC, in a novel mechanism of resistance to endocrine therapy in ER+ BC that has potential as a therapeutic target.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0713-5) contains supplementary material, which is available to authorized users.

Mediation of Racial and Ethnic Disparities in Estrogen/Progesterone Receptor-Negative Breast Cancer by Socioeconomic Position and Reproductive Factors

Hispanic and non-Hispanic black breast cancer patients are more likely than non-Hispanic white patients to be diagnosed with breast cancer that is negative for estrogen and progesterone receptors (ER/PR-negative). This disparity might be transmitted through socioeconomic and reproductive factors. Data on 746 recently diagnosed breast cancer patients (300 non-Hispanic white, 303 non-Hispanic black, 143 Hispanic) were obtained from the population-based Breast Cancer Care in Chicago Study (Chicago, Illinois, 2005-2008). Income, educational level, and census tract measures of concentrated disadvantage and affluence were combined into a single measure of socioeconomic position (SEP). Parity and age at first birth were combined into a single measure of reproductive factors (RPF). We constructed path models to estimate direct and indirect associations of SEP and RPF, and we estimated average marginal controlled direct associations. Compared with non-Hispanic white patients, non-Hispanic black patients and Hispanic patients were more likely to have ER/PR-negative disease (28% and 20% for non-Hispanic black patients and Hispanic patients, respectively, vs. 12% for non-Hispanic white patients; P ≤ 0.001). The ethnic disparity in ER/PR-negative breast cancer (prevalence difference = 0.13, 95% confidence interval: 0.07, 0.18) was reduced by approximately 60% (prevalence difference = 0.05, 95% confidence interval: -0.04, 0.13) after control for SEP and RPF. At least part of the ethnic disparity in the aggressiveness of breast tumors might be transmitted through social influences on tumor biology.

The immune system and hormone-receptor positive breast cancer: Is it really a dead end?

Even if breast cancer has not been traditionally considered an immunogenic tumor, recent data suggest that immunity, and its interaction with tumor cells and tumor microenvironment, might play an important role in this malignancy, in particular in triple negative and HER2+ subtypes. As no consistent data on the potential clinical relevance of tumor infiltrating lymphocytes have been produced in hormone receptor positive (HR+) HER2- breast cancer, the interest in studying immune aspects in this subtype has become less appealing. Nevertheless, some scattered evidence indicates that immunity and inflammation may be implicated in the biology of this subtype as well. In HR+ breast cancer, the interaction between tumor cells and the immune milieu might rely on different mechanisms than in other BC subtypes, involving the modulation of the tumor microenvironment by mutual interplays of endocrine factors, pro-inflammatory status and immune cells. These subtle mechanisms may require more refined methods of evaluation, such as the assessment of tumor infiltrating lymphocytes subpopulations or gene signatures. In this paper we aim to perform a comprehensive review of pre-clinical and clinical data on the interplay between the immune system and breast cancer in the HR+ subtype, to guide further research in the field.

Longitudinal noninvasive imaging of progesterone receptor as a predictive biomarker of tumor responsiveness to estrogen deprivation therapy

PURPOSE

To investigate whether longitudinal functional PET imaging of mammary tumors using the radiopharmaceuticals [(18)F]FDG (to measure glucose uptake), [(18)F]FES [to measure estrogen receptor (ER) levels], or [(18)F]FFNP [to measure progesterone receptor (PgR) levels] is predictive of response to estrogen-deprivation therapy.

EXPERIMENTAL DESIGN

[(18)F]FDG, [(18)F]FES, and [(18)F]FFNP uptake in endocrine-sensitive and -resistant mammary tumors was quantified serially by PET before ovariectomy or estrogen withdrawal in mice, and on days 3 and 4 after estrogen-deprivation therapy. Specificity of [(18)F]FFNP uptake in ERα(+) mammary tumors was determined by competition assay using unlabeled ligands for PgR or glucocorticoid receptor (GR). PgR expression was also assayed by immunohistochemistry (IHC).

RESULTS

The levels of [(18)F]FES and [(18)F]FDG tumor uptake remained unchanged in endocrine-sensitive tumors after estrogen-deprivation therapy compared with those at pretreatment. In contrast, estrogen-deprivation therapy led to a reduction in PgR expression and [(18)F]FFNP uptake in endocrine-sensitive tumors, but not in endocrine-resistant tumors, as early as 3 days after treatment; the changes in PgR levels were confirmed by IHC. Unlabeled PgR ligand R5020 but not GR ligand dexamethasone blocked [(18)F]FFNP tumor uptake, indicating that [(18)F]FFNP bound specifically to PgR. Therefore, a reduction in FFNP tumor to muscle ratio in mammary tumors predicts sensitivity to estrogen-deprivation therapy.

CONCLUSIONS

Monitoring the acute changes in ERα activity by measuring [(18)F]FFNP uptake in mammary tumors predicts tumor response to estrogen-deprivation therapy. Longitudinal noninvasive PET imaging using [(18)F]FFNP is a robust and effective approach to predict tumor responsiveness to endocrine treatment.

The kinome associated with estrogen receptor-positive status in human breast cancer

Estrogen receptor alpha (ERα) regulates and is regulated by kinases involved in several functions associated with the hallmarks of cancer. The following literature review strongly suggests that distinct kinomes exist for ERα-positive and -negative human breast cancers. Importantly, consistent with the known heterogeneity of ERα-positive cancers, different subgroups exist, which can be defined by different kinome signatures, which in turn are correlated with clinical outcome. Strong evidence supports the interplay of kinase networks, suggesting that targeting a single node may not be sufficient to inhibit the network. Therefore, identifying the important hubs/nodes associated with each clinically relevant kinome in ER+ tumors could offer the ability to implement the best therapy options at diagnosis, either endocrine therapy alone or together with other targeted therapies, for improved overall outcome.

Discovery of novel aromatase inhibitors using a homogeneous time-resolved fluorescence assay

AIM

Aromatase is an important target for drugs to treat hormone-dependent diseases, including breast cancer. The aim of this study was to develop a homogeneous time-resolved fluorescence (HTRF) aromatase assay suitable for high-throughput screening (HTS).

METHODS

A 384-well aromatase HTRF assay was established, and used to screen about 7000 compounds from a compound library. Anti-proliferation activity of the hit was evaluated using alamarBlue(R) assay in a hormone-dependent breast cancer cell line T47D. Molecular docking was conducted to elucidate the binding mode of the hit using the Discovery Studio program.

RESULTS

The Z' value and signal to background (S/B) ratio were 0.74 and 5.4, respectively. Among the 7000 compounds, 4 hits (XHN22, XHN26, XHN27 and triptoquinone A) were found to inhibit aromatase with IC50 values of 1.60±0.07, 2.76±0.24, 0.81±0.08 and 45.8±11.3 μmol /L, respectively. The hits XHN22, XHN26 and XHN27 shared the same chemical scaffold of 4-imidazolyl quinoline. Moreover, the most potent hit XHN27 at 10 and 50 μmol/L inhibited the proliferation of T47D cells by 45.3% and 35.2%, respectively. The docking study revealed that XHN27 docked within the active site of aromatase and might form a hydrogen bond and had a π-cation interaction with amino acid residues of the protein.

CONCLUSION

XHN27, an imidazolyl quinoline derivative of flavonoid, is a potent aromatase inhibitor with anti-proliferation activity against breast cancer in vitro. The established assay can be used in HTS for discovering novel aromatase inhibitor.

The pERK of being a target: Kinase regulation of the orphan nuclear receptor ERRγ

Estrogen-related receptors (ERRs) are orphan members of the nuclear receptor superfamily that are important regulators of mitochondrial metabolism with emerging roles in cancer. In the absence of an endogenous ligand, ERRs are reliant upon other regulatory mechanisms that include protein/protein interactions and post-translational modification, though the cellular and clinical significance of this latter mechanism is unclear. We recently published a study in which we establish estrogen-related receptor gamma (ERRγ) as a target for extracellular signal-regulated kinase (ERK), and show that regulation of ERRγ by ERK has important consequences for the function of this receptor in cellular models of estrogen receptor-positive (ER+) breast cancer. In this Research Highlight, we discuss the implications of these findings from a molecular and clinical perspective.