Targeted therapies for ER+/HER2- metastatic breast cancer

Synthesis, characterization and bioactivity of new pyridine-2(H)-one, nicotinonitrile, and furo[2,3-b]pyridine derivatives

Pyridone heterocycles, such as furo[2,3-b]pyridines, have emerged as prominent scaffolds in medicinal chemistry due to their versatile pharmacological properties, including significant anticancer activity. In this study, we successfully synthesized new pyridine-2(H)-one, nicotinonitrile, and furo[2,3-b]pyridine derivatives from chalcones bearing 4-(benzyloxy)phenyl and dichlorothiophenyl subunits to explore their therapeutic potential against breast cancer. By employing a synthetic strategy involving Claisen-Schmidt condensation followed by sequential cyclizations and functional modifications, we synthesized and characterized four compounds (MI-S0, MI-S1, MI-S2, and MI-S3) using various spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR, DEPT, H,H- and C,H-COSY, and HRMS. The in vitro cytotoxic activity of these compounds was evaluated against two breast cancer cell lines, MCF-7 and MDA-MB-231, and compared with a noncancerous breast cell line, MCF-10A. All compounds exhibited potent cytotoxic activities with minimal selectivity toward normal cells. Molecular docking studies targeting the serine/threonine kinase AKT1, estrogen receptor alpha (ERα), and human epidermal growth factor receptor 2 (HER2) revealed strong binding affinities, suggesting a mechanism involving the disruption of key cellular signaling pathways. These findings underscore the potential of furo[2,3-b]pyridine derivatives as promising candidates for further development into anticancer agents, laying the groundwork for future investigations into their selective therapeutic efficacy and molecular mechanisms of action.

Quantitative characterization of the effects of fulvestrant alone or in combination with taselisib (PI3Kinase inhibitor) on longitudinal tumor growth in patients with estrogen receptor-positive, HER2-negative, PIK3CA-mutant, advanced or metastatic breast cancer

PURPOSE

Among cases of breast cancer, estrogen receptor-positive (ER +), PIK3CA-mutant, HER2- advanced breast cancer stands as a particularly complex clinical indication where approximately 40% of ER + /HER2- breast carcinomas present mutations in the PIK3CA gene. A significant hurdle in treating ER + breast cancer lies in surmounting the challenges of endocrine resistance. In the clinical setting, a multifaceted approach is essential for this indication, one that not only explores the effectiveness of individual treatments but also delves into the potential gains in therapeutic outcome from combination therapies.

METHODS

In the current study, longitudinal tumor growth inhibition (TGI) models were developed to characterize tumor response over time in postmenopausal women with ER + /HER2- advanced or metastatic breast cancer undergoing treatment with fulvestrant alone or in combination with the PI3K inhibitor, taselisib. Impact of clinically relevant covariates on TGI metrics was assessed to identify patient subsets most likely to benefit from treatment with fulvestrant monotherapy or combination with taselisib.

RESULTS

Tumor growth rate constant (Kg) was found to increase with increasing baseline tumor size and in the absence of baseline endocrine sensitivity. Further, Kg decreased in the absence of baseline liver metastases both in fulvestrant monotherapy and combination therapy with taselisib. Overall, additive/potentially synergistic anti-tumor effects were observed in patients treated with the taselisib-fulvestrant combination.

CONCLUSION

These results have important implications for understanding the therapeutic impact of combination treatment approaches and individualized responses to these treatments. Finally, this work, emphasizes the importance of model informed drug development for targeted cancer therapy.

CLINICAL TRIAL REGISTRATION

NCT02340221 Registered January 16, 2015, NCT01296555 Registered February 14, 2011.

HR-positive/HER2-negative breast cancer arising in patients with or without BRCA2 mutation: different biological phenotype and similar prognosis

Background

BRCA2 plays a key role in homologous recombination. However, information regarding its mutations in Chinese patients with breast cancer remains limited.

Objectives

This study aimed to assess the clinicopathological characteristics of BRCA2 mutation breast cancer and explore the mutation's effect on hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer survival in China.

Design

This hospital-based cohort study prospectively included 629 women with breast cancer diagnosed from 2008 to 2023 at Zhejiang Cancer Hospital in China.

Methods

We compared the clinicopathological characteristics and metastatic patterns and analysed the invasive disease-free survival (iDFS), distant relapse-free survival (DRFS) and first-line progression-free survival (PFS1) of patients with HR-positive/HER2-negative breast cancer according to BRCA2 mutations.

Results

Among the 629 patients, 78 had BRCA2 mutations (12.4%) and 551 did not (87.6%). The mean age at diagnosis was lower in the BRCA2 mutation breast cancer group than in the non-mutation breast cancer group (38.91 versus 41.94 years, p = 0.016). BRCA2 mutation breast cancers were more likely to be lymph node-positive than non-mutation breast cancers (73.0% versus 56.6%, p = 0.037). The pathological grade was higher in 47.1% of BRCA2 mutation breast cancers than in 29.6% of non-mutation breast cancers (p = 0.014). The proportions of patients with BRCA2 mutations who developed contralateral breast cancer (19.2% versus 8.8%, p = 0.004), breast cancer in the family (53.8% versus 38.3%, p = 0.009) and ovarian cancer in the family (7.6% versus 2.4%, p = 0.022) were higher than those of patients without the mutation. The median follow-up time was 92.78 months. Multivariate analysis showed that BRCA2 mutation was not associated with poorer iDFS [hazard ratio = 0.9, 95% confidence interval (CI) = 0.64-1.27, p = 0.56] and poorer distant relapse-free survival (DRFS) (hazard ratio = 1.09, 95% CI = 0.61-1.93, p = 0.76). There was no significant difference between the two groups with regard to metastatic patterns in the advanced disease setting. In the first-line metastatic breast cancer setting, PFS1 expression was broadly similar between the two groups irrespective of chemotherapy or endocrine therapy.

Conclusion

HR-positive/HER2-negative breast cancer with BRCA2 mutations differs from those without mutations in clinical behaviour and reflects more aggressive tumour behaviour. Our results indicate that BRCA2 mutations have no significant effect on the survival of Chinese women with HR-positive/HER2-negative breast cancer.

CCND1-associated ceRNA network reveal the critical pathway of TPRG1-AS1-hsa-miR-363-3p-MYO1B as a prognostic marker for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSC) is one of the leading causes of cancer death globally, yet there are few useful biomarkers for early identification and prognostic prediction. Previous studies have confirmed that CCND1 amplification is closely associated with head and neck oncogenesis, and the present study explored the ceRNA network associated with CCND1. Gene expression profiling of the Head and Neck Squamous Cell Carcinoma (HNSC) project of The Cancer Genome Atlas (TCGA) program identified the TPRG1-AS1-hsa-miR-363-3P-MYO1B gene regulatory axis associated with CCND1. Further analysis of the database showed that MYOB was regulated by methylation in head and neck tumors, and functional enrichment analysis showed that MYO1B was involved in "actin filament organization" and "cadherin binding ". Immune infiltration analysis suggested that MYO1B may influence tumorigenesis and prognosis by regulating the immune microenvironment of HNSC. MYO1B enhanced tumor spread through the EMT approach, according to epithelial mesenchymal transition (EMT) characterisation. We analyzed both herbal and GSCALite databases and found that CCND1 and MYO1B have the potential as predictive biomarkers for the treatment of HNSC patients. RT-qPCR validated bioinformatic predictions of gene expression in vitro cell lines. In conclusion, we found a CCND1-related ceRNA network and identified the novel TPRG1-AS1-hsa-miR-363-3p-MYO1B pathway as a possible HNSC diagnostic biomarker and therapeutic target.

The RUNX/CBFβ Complex in Breast Cancer: A Conundrum of Context

Dissecting and identifying the major actors and pathways in the genesis, progression and aggressive advancement of breast cancer is challenging, in part because neoplasms arising in this tissue represent distinct diseases and in part because the tumors themselves evolve. This review attempts to illustrate the complexity of this mutational landscape as it pertains to the RUNX genes and their transcription co-factor CBFβ. Large-scale genomic studies that characterize genetic alterations across a disease subtype are a useful starting point and as such have identified recurring alterations in CBFB and in the RUNX genes (particularly RUNX1). Intriguingly, the functional output of these mutations is often context dependent with regards to the estrogen receptor (ER) status of the breast cancer. Therefore, such studies need to be integrated with an in-depth understanding of both the normal and corrupted function in mammary cells to begin to tease out how loss or gain of function can alter the cell phenotype and contribute to disease progression. We review how alterations to RUNX/CBFβ function contextually ascribe to breast cancer subtypes and discuss how the in vitro analyses and mouse model systems have contributed to our current understanding of these proteins in the pathogenesis of this complex set of diseases.

Tissue and liquid biopsy profiling reveal convergent tumor evolution and therapy evasion in breast cancer

Pathological and genomic profiling have transformed breast cancer care by matching patients to targeted treatments. However, tumors evolve and evade therapeutic interventions often through the acquisition of genomic mutations. Here we examine patients profiled with tissue (TBx) and liquid biopsy (LBx) as part of routine clinical care, to characterize the tumor evolutionary landscape and identify potential vulnerabilities in the relapsed setting. Real-world evidence demonstrates that LBx is utilized later in care and identifies associations with intervening therapy. While driver events are frequently shared, acquired LBx alterations are detected in a majority of patients, with the highest frequency in ER+ disease and in patients with longer biopsy intervals. Acquired mutations are often polyclonal and present at lower allelic fractions, suggesting multi-clonal convergent evolution. In addition to well-characterized resistance mutations (e.g., ESR1, NF1, RB1, ERBB2), we observe a diversity of rarer but potentially targetable mutations (e.g., PIK3CA, HRAS/NRAS/KRAS, FGFR1/2/3, BRAF) and fusions (e.g., FGFR1/2, ERBB2, RET), as well as BRCA1/2 reversions through a variety of mechanisms, including splice alterations and structural deletions. This study provides insights on treatment and selection-driven tumor evolution and identifies potential combinatorial treatment options in advanced breast cancer.

Checkpoint Kinase 1 (CHK1) Functions as Both a Diagnostic Marker and a Regulator of Epithelial-to-Mesenchymal Transition (EMT) in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is more difficult to treat and has a higher mortality rate than other subtypes. Although hormone receptor-targeted therapy is an effective treatment to increase survival rate in breast cancer patients, it is not suitable for TNBC patients. To address the issues, differentially expressed genes (DEGs) in TNBC patients from the Gene Expression Omnibus (GEO) database were analyzed. A total of 170 genes were obtained from three Genomic Spatial Events (GSEs) using the intersection of each GSE dataset and 61 DEGs were identified after validation with the gene enrichment analysis. We combined this with the degree scores from the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction (PPI) network, of which 7 genes were correlated with survival rate. Finally, a proteomics database revealed that only the CHK1 protein level was differently expressed in basal-like compared with other subtypes. We demonstrated that CHK1 expression was higher in TNBC cell lines compared with non-TNBC cell lines, and CHK1 promotes epithelial to mesenchymal transition (EMT) as well as migration and invasion ability. Our study provides new insight into the TNBC subnetwork that may be useful in the prognosis and treatment of TNBC patients.

Stealth Liposomal Chemotherapeutic Agent for Triple Negative Breast Cancer with Improved Pharmacokinetics

Triple-negative breast cancer is one of the most lethal cancers. Chemotherapeutics for targeting CDK4 and CDK6 like Palbociclib (PAB) in triple-negative breast cancer was widely explored. However, poor bioavailability and severe side effects profile limiting its clinical usage in the field of cancer chemotherapy. Herein, we set out to develop the stealth liposomes (LPS) of PAB by rotary thin film evaporation with a vesicle size of less than 100 nm. In vitro, drug release studies were performed and fitted into different release kinetic models. LPS were characterized by electron microscopic techniques for morphology. The engineered nanotherapeutics agents were further evaluated in 4T1 triple-negative breast cancer cell lines for its anti-cancer potential and cellular uptake. The hemolytic potential and pharmacokinetic (PK) behavior of developed LPS-PAB and PAB were analyzed by using robust UHPLC-QTOF-MS method. LPS-PAB demonstrates biphasic release profile with first-order release kinetics. Further, LPS-PAB has shown less IC₅₀ value (1.99 µM) compared to PAB alone (3.24 µM). The designed nanoliposomes were tagged with fluorescent FITC dye to check rapid cellular uptake. Importantly, stealth LPS-PAB has shown a 1.75-fold reduction in hemolytic potential as compared to PAB plain drug at 100 µg/mL concentration. The PK results obtained was displayed 2.5-fold increase in C_max, 1.45-fold increase in AUC_tot, 1.8-fold increase in half-life and 1.3-fold increase in MRT with LPS-PAB when compared to orally administered PAB suspension. These findings suggest that novel LPS-PAB can be employed as an alternate therapeutic strategy to eradicate triple-negative breast cancer.

Ribociclib plus letrozole in patients with hormone receptor-positive, HER2-negative advanced breast cancer with no prior endocrine therapy: subgroup safety analysis from the phase 3b CompLEEment-1 trial

BACKGROUND

The CDK4/6 inhibitor, ribociclib in combination with endocrine therapy significantly improved progression-free survival in the first line setting in post-menopausal patients with HR+/HER2- advanced breast cancer (ABC) in a pivotal phase 3, placebo-controlled trial (MONALEESA-2) and demonstrated superior overall survival in premenopausal patients with HR+/HER2- ABC (MONALEESA-7). The multinational, phase 3b, CompLEEment-1 trial, which assessed the safety and efficacy of ribociclib plus letrozole in a broader population of patients who have not received prior endocrine therapy for advanced disease, is the largest phase 3 clinical trial to date to evaluate the safety and efficacy of a CDK4/6 inhibitor. We report a subanalysis of data from patients (N = 339) enrolled in the central and south European countries of the SERCE (Southern Europe, RUC, Central Europe) cluster of CompLEEment-1.

PATIENTS AND METHODS

Men and women of any menopausal status with HR+/HER2- ABC received once-daily oral ribociclib 600 mg (3-weeks on/1-week-off), plus letrozole 2.5 mg continuously. Men/premenopausal women also received a GnRH-agonist. The primary outcome was the number of patients with adverse events (AEs) over a timeframe of approximately 36 months. Time-to-progression, overall response rate, and clinical benefit rate were also measured.

RESULTS

Safety results in the SERCE subgroup were consistent with those in the pivotal clinical trials of ribociclib in combination with endocrine therapy. Treatment-related AEs leading to dose adjustments/interruption occurred in 63.1% of patients but led to treatment discontinuation in only 10.6%. The most common treatment-related AEs of grade ≥ 3 were neutropenia and transaminase elevations. There were no fatal treatment-related events.

CONCLUSIONS

These findings from the SERCE subgroup support the safety and manageable tolerability of ribociclib in a broad range of patients with HR+/HER2- ABC more representative of patients in real-world clinical practice.

A real-world retrospective study of the use of Ki-67 testing and treatment patterns in patients with HR+, HER2- early breast cancer in the United States

Background

The National Comprehensive Cancer Network recommends that patients with hormone receptor-positive early breast cancer be considered for adjuvant endocrine therapy (ET) after primary treatment like surgical excision. Adjuvant chemotherapy (CT) use primarily depends on risk of recurrence. Biomarkers such as Ki-67 potentially have most value in patients with intermediate risk factors, such as involvement of 1–3 positive nodes. This study evaluated the use of Ki-67 testing and treatment patterns in patients with HR+, human epidermal growth factor receptor 2-negative early breast cancer.

Methods

This was an observational retrospective cohort study of patients with electronic medical records from January 2010 to August 2018 treated for HR+, HER2− early breast cancer at Sarah Cannon sites in the United States (US). Overall, 567 patients were randomly selected after using the eligibility criteria: female or male ≥18 years, without distant metastases, and with available physician and pathology reports. Multivariable logistic regression was used to investigate factors predicting Ki-67 testing and test results. Descriptive analyses were applied to treatment patterns.

Results

Multivariable logistic regression analyses found no clinical or pathological factors that predicted whether Ki-67 testing had been ordered by physicians. Of all tested patients (N = 130), having Grade-2 tumors (OR, 7.95 [95% CI: 2.05, 30.9]; p = 0.0027) or Grade-3 tumors (OR, 95.3 [95% CI, 11.9, 760.7]; p < 0.001) at initial diagnosis was a predictor of high Ki-67 expression (≥20%). Ki-67 expression was tested in 23.6% (61/258) of patients with 1–3 positive nodes; 54.1% of them (33/61) had high Ki-67 expression (≥20%). While having a higher grade tumor predicted high Ki-67 (≥20%), 28.6% of patients with Grade-1 tumors also had high Ki-67 expression. Neo-adjuvant therapy was received by 16.0% of patients (91/567), most of whom (66/91; 72.5%) received CT alone. Adjuvant therapy, either endocrine and/or chemotherapy, was received by 92.6% (525/567) of patients and by 67.0% (61/91) of those who received neo-adjuvant therapy. Most (428/525, 81.5%) received ET in the adjuvant treatment setting.

Conclusions

High grade tumors predicted high Ki-67 (≥20%) expression, but Ki-67 testing was not widely used in these US patients. Most HR+, HER2− early breast cancers were treated with adjuvant ET, with or without CT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09557-6.

Circulating tumor cells, circulating tumor DNA, and disease characteristics in young women with metastatic breast cancer

BACKGROUND

Clinical and genomic data from patients with early-stage breast cancer suggest more aggressive disease in premenopausal women. However, the association between age, disease course, and molecular profile from liquid biopsy in metastatic breast cancer (MBC) is not well characterized.

METHODS

Patients were classified as premenopausal (< 45 years), perimenopausal (45-55 years), or postmenopausal (> 55 years). Cohort 1 consisted of patients with MBC who consented for prospective serial evaluation of circulating tumor cells (CTCs) using CellSearch™. Cohort 2 included patients who, as part of routine care, had circulating tumor DNA (ctDNA) sequenced by the Guardant360™ assay. Clinicopathologic data were collected from retrospective review to compare disease features between premenopausal and postmenopausal women.

RESULTS

Premenopausal women represented 26% of 138 patients in Cohort 1 and 21% of 253 patients in Cohort 2. In Cohort 1, younger patients had a shorter time to metastases and a higher prevalence of lung and brain metastases. Overall, there were similar rates of ≥ 5 CTCs/7.5 mL, HER2 + CTC expression, and CTC clusters between pre- and postmenopausal women. However, for those with triple negative breast cancer, premenopausal women had a higher proportion of ≥ 5 CTCs/7.5 mL. In Cohort 2, premenopausal women had a higher incidence of FGFR1 (OR 2.75, p = 0.022) and CCND2 (OR 6.91, p = 0.024) alterations. There was no difference in the ctDNA mutant allele frequency or the number of detected alterations between these age groups.

CONCLUSIONS

Our data reveal that premenopausal women diagnosed with MBC have unique clinical, pathologic, and molecular features when compared to their postmenopausal counterparts. Our results highlight FGFR1 inhibitors as potential therapeutics of particular interest among premenopausal women.

The impact of new systemic therapies on survival and time on hormonal treatment in hormone receptor-positive, human epidermal growth factor receptor 2-negative metastatic breast cancer: A population-based study in British Columbia from 2003 to 2013

BACKGROUND

The purpose of this study was to determine whether new systemic therapy regimens have resulted in improved survival and increased time on first- and second-line hormonal treatment for patients with hormone receptor (HR)-positive metastatic breast cancer (MBC) over time.

METHODS

Patients diagnosed with HR-positive, human epidermal growth factor receptor 2 (HER2)-negative MBC were identified across 3 time cohorts (2003-2005, 2007-2009, and 2011-2013). Data were prospectively collected. Cases with previous, synchronous, or subsequent contralateral breast cancer were excluded. The types of first- and second-line therapies, the times on first- and second-line hormonal treatment, and the median survival times were compared across the cohorts.

RESULTS

Within the time period analyzed, 9 new adjuvant systemic therapies (with or without neoadjuvant therapy) and 2 metastatic systemic therapies were approved at BC Cancer for the treatment of HR-positive, HER2-negative MBC. In the 3 time cohorts, 3953 patients diagnosed with MBC were identified. Among the 2432 patients (62%) who had HR-positive/HER2-negative disease, 2197 (90%) received at least 1 line of systemic therapy after the diagnosis of MBC, and 80% of these patients (1752 of 2197) received first- and/or second-line hormonal treatment. The median duration on hormonal treatment was 9.0 months for the first line and 6.1 months for the second line. The durations were similar across the time cohorts (range for the first line, 8.9-9.0 months; range for the second line, 6.0-6.1 months). The median survival for the entire study population was 2.0 years (95% confidence interval, 1.8-2.1 years), and there was no significant difference between the cohorts (range, 1.9-2.0 years).

CONCLUSIONS

Even though more adjuvant and metastatic systemic therapies have been approved since 2003, population-level gains in survival and the time on hormonal treatment for patients with HR-positive, HER2-negative MBC have not been made over the course of a decade.

Downregulation of CYB5D2 is associated with breast cancer progression

We report here that CYB5D2 is associated with tumor suppression function in breast cancer (BC). CYB5D2 expression was significantly reduced in tamoxifen resistant MCF7 cells and in MCF7 cell-derived xenografts treated with TAM. CYB5D2 overexpression induced apoptosis in MCF7 cells; CYB5D2 knockdown enhanced MCF7 cell proliferation. Using the TCGA and Curtis datasets within the Oncomine database, CYB5D2 mRNA expression was downregulated in primary BCs vs breast tissues and HER2-positive or triple negative BCs vs estrogen receptor (ER)-positive BCs. Using the TCGA and Metabric datasets (n = 817 and n = 2509) within cBioPortal, 660 and 4891 differentially expressed genes (DEGs) in relation to CYB5D2 were identified. These DEGs were enriched in pathways governing cell cycle progression, progesterone-derived oocyte maturation, oocyte-meiosis, estrogen-mediated S-phase entry, and DNA metabolism. CYB5D2 downregulation decreased overall survival (OS, p = 0.0408). A CYB5D2-derived 21-gene signature was constructed and robustly correlated with OS shortening (p = 5.72e-12), and independently predicted BC deaths (HR = 1.28; 95% CI 1.08–1.52; p = 0.004) once adjusting for known clinical factors. CYB5D2 reductions displayed relationship with mutations in PIK3CA, GATA3, MAP3K1, CDH1, TP53 and RB1. Impressively, 85% (560/659) of TP53 mutations occurred in the 21-gene signature-positive BC. Collectively, we provide the first evidence that CYB5D2 is a candidate tumor suppressor of BC.

Neratinib in HER2-Positive Breast Cancer Patients

OBJECTIVE

To review the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of neratinib in human epidermal growth factor receptor (HER2)+ breast cancer (BC).

DATA SOURCES

A PubMed search was performed using the term neratinib between September 12, 2018, and November 21, 2018. References of published articles and reviews were also assessed for additional information.

STUDY SELECTION AND DATA EXTRACTION

English-language preclinical and clinical studies on the chemistry, pharmacology, pharmacokinetics, safety, and efficacy of neratinib were evaluated.

DATA SYNTHESIS

Neratinib, an irreversible inhibitor of HER1, HER2, and HER4, is Food and Drug Administration approved for the extended adjuvant treatment of stage I-III HER2+ BC to follow trastuzumab-based therapy. A phase III study has demonstrated statistically significant improvement in 5-year disease-free survival rate (90.2 vs 87.7; hazard ratio = 0.73, 95% CI = 0.57-0.92, P = 0.0083). Its most common adverse effect is diarrhea, observed in more than 90% of patients. The incidence of grade 3/4 diarrhea (~40%) is reduced by half with loperamide prophylaxis, which is recommended for the first 8 weeks of neratinib therapy. Other common adverse reactions are nausea and fatigue. The patients need to be monitored for liver function tests and drug interactions with acid-reducing agents, CYP3A4 inhibitors/inducers, and P-glycoprotein substrates with narrow therapeutic window. Relevance to Patient Care and Clinical Practice: American Society of Clinical Oncology and National Comprehensive Cancer Network clinical guidelines suggest the use of neratinib for extended adjuvant therapy following 1-year trastuzumab in stage I to III HER2+ BC. Diarrhea remains a clinically significant but manageable adverse event.

CONCLUSION

Neratinib significantly improves treatment outcomes and has manageable toxicity in stage I to III HER2+ BC patients.

Ribociclib for the first-line treatment of advanced hormone receptor-positive breast cancer: a review of subgroup analyses from the MONALEESA-2 trial

Abstract

Endocrine therapy is recommended for patients with hormone receptor-positive (HR⁺) advanced and metastatic breast cancer without visceral crisis (symptomatic visceral disease). However, many patients experience disease progression during treatment, and most patients eventually develop endocrine resistance. Therefore, it is important to identify treatment options that prolong the effectiveness of first-line endocrine therapies. Ribociclib is an orally bioavailable cyclin-dependent kinase (CDK) 4/6 inhibitor that has been approved for use in combination with an aromatase inhibitor for the treatment of HR⁺, human epidermal growth factor receptor 2-negative (HER2⁻) advanced breast cancer. This approval is based on findings from the MONALEESA-2 study, a double-blind, placebo-controlled, randomized phase 3 trial (NCT01958021) in which first-line therapy with ribociclib + letrozole significantly improved progression-free survival (PFS) compared with placebo + letrozole in patients with HR⁺/HER2⁻ advanced breast cancer. This review will discuss the overall findings from the MONALEESA-2 study and will provide a summarized analysis of results from the available subgroups in the study by age, visceral metastases, bone-only disease, de novo disease, and prior therapy. On the basis of these data, ribociclib has established itself as a beneficial treatment option for these different populations.

Trial registration

ClinicalTrials.gov, NCT01958021. Registered on 8 October 2013.

E-cadherin loss induces targetable autocrine activation of growth factor signalling in lobular breast cancer

Despite the fact that loss of E-cadherin is causal to the development and progression of invasive lobular carcinoma (ILC), options to treat this major breast cancer subtype are limited if tumours develop resistance to anti-oestrogen treatment regimens. This study aimed to identify clinically targetable pathways that are aberrantly active downstream of E-cadherin loss in ILC. Using a combination of reverse-phase protein array (RPPA) analyses, mRNA sequencing, conditioned medium growth assays and CRISPR/Cas9-based knock-out experiments, we demonstrate that E-cadherin loss causes increased responsiveness to autocrine growth factor receptor (GFR)-dependent activation of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt signalling. Autocrine activation of GFR signalling and its downstream PI3K/Akt hub was independent of oncogenic mutations in PIK3CA, AKT1 or PTEN. Analyses of human ILC samples confirmed growth factor production and pathway activity. Pharmacological inhibition of Akt using AZD5363 or MK2206 resulted in robust inhibition of cell growth and survival of ILC cells, and impeded tumour growth in a mouse ILC model. Because E-cadherin loss evokes hypersensitisation of PI3K/Akt activation independent of oncogenic mutations in this pathway, we propose clinical intervention of PI3K/Akt in ILC based on functional E-cadherin inactivation, irrespective of activating pathway mutations.

Emerging ways to treat breast cancer: will promises be met?

BACKGROUND

Breast cancer (BC) is the most common cancer among women and it is responsible for more than 40,000 deaths in the United States and more than 500,000 deaths worldwide each year. In previous decades, the development of improved screening, diagnosis and treatment methods has led to decreases in BC mortality rates. More recently, novel targeted therapeutic options, such as the use of monoclonal antibodies and small molecule inhibitors that target specific cancer cell-related components, have been developed. These components include ErbB family members (HER1, HER2, HER3 and HER4), Ras/MAPK pathway components (Ras, Raf, MEK and ERK), VEGF family members (VEGFA, VEGFB, VEGFC, VEGF and PGF), apoptosis and cell cycle regulators (BAK, BAX, BCL-2, BCL-X, MCL-1 and BCL-W, p53 and PI3K/Akt/mTOR pathway components) and DNA repair pathway components such as BRCA1. In addition, long noncoding RNA inhibitor-, microRNA inhibitor/mimic- and immunotherapy-based approaches are being developed for the treatment of BC. Finally, a novel powerful technique called CRISPR-Cas9-based gene editing is emerging as a precise tool for the targeted treatment of cancer, including BC.

CONCLUSIONS

Potential new strategies that are designed to specifically target BC are presented. Several clinical trials using these strategies are already in progress and have shown promising results, but inherent limitations such as off-target effects and low delivery efficiencies still have to be resolved. By improving the clinical efficacy of current therapies and exploring new ones, it is anticipated that novel ways to overcome BC may become attainable.

Progression-free survival with endocrine-based therapies following progression on non-steroidal aromatase inhibitor among postmenopausal women with hormone receptor positive, human epidermal growth factor receptor-2 negative metastatic breast cancer: a network meta-analysis

OBJECTIVE

To quantify the comparative efficacy of currently available endocrine-based therapies (ETs) for postmenopausal women with hormone receptor positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) metastatic breast cancer (mBC) after non-steroidal aromatase inhibitor (NSAI) progression.

DESIGN

Network meta-analysis (NMA).

METHODS

Randomized clinical trials of ETs for HR+/HER2- mBC were identified via a systematic literature review using MEDLINE, Embase, Cochrane Library and key conference proceedings. All trials met the following inclusion criteria: (1) included women with HR+/HER2- mBC; (2) previous treatment with ETs or chemotherapy as first-line therapy; (3) treatment with ET as monotherapy or in combination with targeted therapy; (4) progression-free survival (PFS) was reported; and (5) published in 2007 (when HER2 testing became standardized) or later. Regimens were compared using pairwise hazard ratios (HRs) and 95% credible intervals (CrIs) of PFS obtained from a Bayesian NMA. Treatments with different approved dosages were pooled into the same arm; anastrozole and exemestane were pooled as aromatase inhibitors (AIs) due to clinical similarities.

RESULTS

A total of 4 trials and 6 regimens (palbociclib + fulvestrant, everolimus + fulvestrant, everolimus + AI, fulvestrant + AI, fulvestrant and AI) were eligible for inclusion. Palbociclib + fulvestrant and everolimus + AI had 50% and 55% reduced hazard of progression or death vs. AI (95% CrI upper bound ≤1), respectively. Palbociclib + fulvestrant, everolimus + AI and everolimus + fulvestrant had 54%, 58% and 40% reduced hazard vs. fulvestrant (95% CrI upper bound ≤1), while palbociclib + fulvestrant and everolimus + AI had 52% and 55% reduced hazard vs. fulvestrant + AI (95% CrI upper bound ≤1), respectively.

CONCLUSION

Postmenopausal women with HR+/HER2- mBC who had previously failed an NSAI and received palbociclib + fulvestrant, everolimus + AI or everolimus + fulvestrant had longer PFS compared to those who received fulvestrant or AI alone.

Emerging findings into molecular mechanism of brain metastasis

Brain metastasis is an important cause of morbidity and mortality in cancer patients. Hence, the need to develop improved therapies to prevent and treat metastasis to the brain is becoming urgent. Recent studies in this area are bringing about some advanced progress on brain metastasis. It was concluded that the occurrence and poor prognosis of brain metastasis have been mostly attributed to the exclusion of anticancer drugs from the brain by the blood-brain barrier. And several highly potent new generation targeted drugs with enhanced CNS distribution have been developed constantly. However, the noted "seed and soil" hypothesis also suggests that the outcome of metastasis depends on the relationship between unique tumor cells and the specific organ microenvironment. Moreover, increasing studies in multiple tumor types demonstrated that brain metastasis has great molecular differences between primary tumors and extracranial metastasis to a large extent. Here, the authors summarized the most common malignancies that could lead to brain metastasis-lung cancer, breast cancer and melanoma and their related mutated factors. Only by comprehending a deeper understanding of the molecular mechanisms, more effective brain-specific therapies will be developed for brain metastasis.

Cancer stem cells in triple-negative breast cancer: a potential target and prognostic marker

Triple-negative breast cancer (TNBC) is an aggressive disease with poor outcome, and lacks targeted therapy. Recent studies suggest that cancer stem cells play an important role in tumorigenesis and tumor biology of TNBC. Both CD44⁺/CD24^- and ALDH1⁺ breast cancer stem cells are enriched in TNBC and may contribute to the propensity of TNBC for chemotherapy resistance and tumor metastasis. There is new evidence to support the evaluation of cancer stem cells in TNBC for diagnostic purposes. Targeting cancer stem cells may also be a promising, novel strategy for the treatment of TNBC. This review highlights the current understanding of breast cancer stem cells in TNBC, with focus on CD44⁺/CD24^- and ALDH1⁺ breast cancer stem cells. It is our hope that this work provides insight into the potential role of cancer stem cells in the prognostication and therapeutic targeting of TNBC.

Safety and Antitumor Activity of Pembrolizumab in Patients with Estrogen Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Advanced Breast Cancer

Purpose: We investigated the safety and antitumor activity of the anti-programmed death 1 monoclonal antibody pembrolizumab in patients with estrogen receptor-positive (ER⁺)/human epidermal growth factor receptor 2-negative (HER2^-) advanced breast cancer with programmed death ligand 1-positive (PD-L1-positive) tumors in the phase Ib open-label, multicohort KEYNOTE-028 (NCT02054806) study.Patients and Methods: Patients with ER⁺/HER2^- advanced breast cancer with PD-L1-positive tumors (combined positive score ≥1) received pembrolizumab (10 mg/kg every 2 weeks) up to 2 years or until confirmed progression/intolerable toxicity. Primary endpoints were safety and overall response rate (ORR), based on Response Evaluation Criteria in Solid Tumors, version 1 (RECIST v1.1) as assessed by investigator review.Results: Between April 2014 and January 2015, 25 patients were enrolled. Median number of prior therapies for breast cancer, including endocrine agents, was 9 (range, 3-15). Median follow-up was 9.7 months (range, 0.7-31.8 months). Three patients experienced partial response (PR) and none experienced complete response (CR), resulting in an ORR of 12.0% (95% CI, 2.5%-31.2%); 16% of patients had stable disease (SD) and clinical benefit rate (CR + PR + [SD for ≥24 weeks]) was 20% (95% CI, 7-41). Median duration of response was 12.0 months (range, 7.4-15.9 months). The incidence of treatment-related adverse events was 64%; nausea (20%) and fatigue (12%) were most common and were predominantly grade 1/2. No treatment-related discontinuations or deaths occurred.Conclusions: Pembrolizumab was well tolerated with modest but durable overall response in certain patients with previously treated, advanced, PD-L1-positive, ER⁺/HER2^- breast cancer. Clin Cancer Res; 24(12); 2804-11. ©2018 AACR.

Dosing Patterns and Economic Burden of Palbociclib Drug Wastage in HR+/HER2- Metastatic Breast Cancer

INTRODUCTION

Targeted therapies have revolutionized the treatment of hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) metastatic breast cancer (mBC). However, as for many oncology drugs, the dose of targeted therapies may need to be adjusted over time, leading to drug wastage when a dose modification is needed but the dose cannot be split or saved. This has been shown to be the case for palbociclib and has led to concerns among payers. This study described palbociclib dosing patterns and estimated the economic burden of the drug wastage associated with palbociclib dose modifications in postmenopausal women with HR+/HER2- mBC.

METHODS

A large US claims database was used to identify postmenopausal women with HR+/HER2- mBC who received a palbociclib-based therapy during one of their first three lines of therapy for mBC between February 2015 (palbociclib approval) and December 2015. Dosing patterns (dosing modifications and sequences) were reported; a dose modification was defined as an increase/decrease of at least 25 mg daily compared to the preceding dose. Estimates of drug wastage costs were based on days with overlap in prescription fills for different palbociclib doses.

RESULTS

A total of 473 postmenopausal palbociclib-treated women with HR+/HER2- mBC were included (first line 214; second line 157; third line 120). Over an average duration of line of therapy of approximately 4 months, dose modification was observed in 17.8%, 31.2%, and 35.0% of patients in first, second, and third line. Average overlap in prescription fills was 9.2, 9.9, and 5.4 days in first, second, and third line. This potential drug wastage resulted in an average cost of $4376, $4740, and $2592 per patient in first, second, and third line.

CONCLUSIONS

This study showed that drug wastage due to palbociclib dose modification results in substantial costs. Treatment options with more flexible dosing may help reduce the costs of drug wastage.

FUNDING

Novartis Pharmaceuticals Corporation.

Evaluation of Prognostic Factors and Proposed Changes to the Modified Tokuhashi Score in Patients With Spinal Metastases From Breast Cancer

STUDY DESIGN

A retrospective study of all patients with histologically confirmed breast cancer spinal metastases presenting to a single institution between May 2001 and April 2012.

OBJECTIVES

The aim of this study was to investigate whether the 2014mT is more accurate than the 2005mT.

SUMMARY OF BACKGROUND DATA

The commonly used 2005 modified Tokuhashi score (2005mT) has become more inaccurate as oncologists move toward treating tumors according to their molecular and genomic profile, rather than their tissue-of-origin. In attempts to improve the accuracy of the 2005mT, a revised score (2014mT) was published, suggesting that hormone receptor negative and triple-negative breast cancer patients be given a modified Tokuhashi histological score of 3 rather than 5.

METHODS

Demographic characteristics, tumor receptor status, clinical findings in relation to the primary tumor and its metastases, and actual survival time were collated. The 2005mT was compared with the 2014mT. Univariate and multivariate Cox regression analyses were used to evaluate the influence of each parameter on survival, and receiver operating characteristic curves were used to determine predictive values of each score version.

RESULTS

Of the 185 patients included, 32 underwent operative treatment, while 153 were managed nonoperatively for their spinal metastases. The overall cohort had a median survival time of 24 months following the diagnosis of spinal metastases, with a 6-month survival rate of 90%. Hormone, HER2 and triple-negative receptor statuses were significant predictors of poorer survival upon multivariate analysis (P = 0.004, P = 0.007, P < 0.001, and P < 0.001, respectively). Age, the original Tokuhashi score components, previous breast surgery for cancer, previous radiotherapy to the breast, previous radiotherapy to the spine, previous chemotherapy, and previous immunotherapy were not significant. At 6 months, the 2005mT AUROC was 0.62, while that of the 2014mT was 0.64 (P = 0.5394).

CONCLUSION

Tumor histological subtype is crucial when prognosticating the survival of patients with breast cancer spinal metastases. Although the 2014mT was marginally more accurate than the 2005mT, its predictive ability remains poor.

LEVEL OF EVIDENCE

3.

Progression-free Survival With First-line Endocrine-based Therapies Among Postmenopausal Women With HR+/HER2- Metastatic Breast Cancer:: A Network Meta-analysis

PURPOSE

The comparative efficacy of endocrine-based therapies (ETs) for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) is not well characterized. This network meta-analysis (NMA) synthesized available evidence on progression-free survival (PFS) with first-line ETs for postmenopausal HR+/HER2- mBC.

METHODS

A systematic literature review identified randomized controlled trials of first-line ETs. Pairwise hazard ratios and 95% credible intervals (CrIs) were obtained via a Bayesian NMA model. Subgroup NMAs were conducted among late progressors (disease-free interval ≥12 months from completion of [neo] adjuvant therapy with letrozole or anastrozole at the time of randomization) and de novo patients, defined as patients whose initial BC diagnosis is mBC.

FINDINGS

Five trials and 5 regimens (ribociclib + an aromatase inhibitor [AI] [LEE + AI], palbociclib + AI [Pal + AI], fulvestrant 250 mg + AI [Ful250 + AI], fulvestrant 500 mg [Ful500], and AI) were selected. LEE + AI, Pal + AI, Ful250 + AI, and Ful500 had significantly longer PFS versus AI (95% CrI upper-bound ≤1). LEE + AI had a 30% and 29%, and Pal + AI had a 31% and 30%, reduced hazard of progression or death versus Ful250 + AI and Ful500 (95% CrI upper-bound ≤1), respectively. The probability of being the most efficacious was 46% for LEE + AI and 54% for Pal + AI. In subgroup analyses among late progressors, LEE + AI had a 4% reduced hazard of progression or death versus Pal + AI but was not statistically significant. In the de novo analysis, Pal + AI and LEE + AI had a 29% and 40% reduced hazard of progression or death versus Ful500, respectively, but were not statistically significant. In both subgroup analyses, all therapies had significantly longer PFS compared with AI.

IMPLICATIONS

Pal + AI, LEE + AI, Ful250 + AI, or Ful500 as first-line treatment for HR+/HER2- mBC had longer PFS than AI alone. Given the lack of head-to-head clinical trials comparing the efficacy of recently approved first-line ETs for HR+/HER2- mBC, these results have important clinical implications for the treatment of HR+/HER2- mBC in the first-line setting.

Hydrogen sulfide and autophagy: A double edged sword

Hydrogen sulfide (H₂S) has been considered the third gaseous signaling molecule that plays important roles in a wide range of physiological and pathological conditions. However, there has been some controversy on the role of H₂S in autophagy. Recent studies indicate that a number of signaling pathways are involved in the pro-autophagy effect of H₂S, such as PI3K/Akt/mTOR, AMPK/mTOR, LKB1/STRAD/MO25, and miR-30c signaling pathways. On the other hand, there are many signaling pathways that play important roles in the anti-autophagy effect of H₂S, including SR-A, PI3K/SGK1/GSK3β, PI3K/AKT/mTOR, Nrf2-ROS-AMPK, AMPK/mTOR, and JNK1 signaling pathways. Novel H₂S-releasing donors/drugs could be designed and identified in order to increase the therapeutic effects by mediating autophagy in human diseases. In this review, the H₂S metabolism in mammals is summarized and the effects of signaling pathways in H₂S-mediated autophagy are further discussed.

Targeting the receptor tyrosine kinase RET in combination with aromatase inhibitors in ER positive breast cancer xenografts

The majority of breast cancers are estrogen receptor positive (ER+). Blockade of estrogen biosynthesis by aromatase inhibitors (AIs) is the first-line endocrine therapy for post-menopausal women with ER+ breast cancers. However, AI resistance remains a major challenge. We have demonstrated previously that increased GDNF/RET signaling in ER+ breast cancers promotes AI resistance. Here we investigated the efficacy of different small molecule RET kinase inhibitors, sunitinib, cabozantinib, NVP-BBT594 and NVP-AST487, and the potential of combining a RET inhibitor with the AI letrozole in ER+ breast cancers. The most effective inhibitor identified, NVP-AST487, suppressed GDNF-stimulated RET downstream signaling and 3D tumor spheroid growth. Ovariectomized mice were inoculated with ER+ aromatase-overexpressing MCF7-AROM1 cells and treated with letrozole, NVP-AST487 or the two drugs in combination. Surprisingly, the three treatment regimens showed similar efficacy in impairing MCF7-AROM1 tumor growth in vivo. However in vitro, NVP-AST487 was superior to letrozole in inhibiting the GDNF-induced motility and tumor spheroid growth of MCF7-AROM1 cells and required in combination with letrozole to inhibit GDNF-induced motility in BT474-AROM3 aromatase expressing cells. These data indicate that inhibiting RET is as effective as the current therapeutic regimen of AI therapy but that a combination treatment may delay cancer cell dissemination and metastasis.

Epoxyazadiradione suppresses breast tumor growth through mitochondrial depolarization and caspase-dependent apoptosis by targeting PI3K/Akt pathway

Background

Breast cancer is one of the most commonly diagnosed invasive cancers among women around the world. Among several subtypes, triple negative breast cancer (TNBC) is highly aggressive and chemoresistant. Treatment of TNBC patients has been challenging due to heterogeneity and devoid of well-defined molecular targets. Thus, identification of novel effective and selective agents against TNBC is essential.

Methods

We used epoxyazadiradione to assess the cell viability, mitochondrial potential, ROS level, cell migration, apoptosis and protein expression in cell culture models of TNBC MDA-MB-231 and ER+ MCF-7 breast cancer cells. The molecular mechanism was examined in two different type of breast cancer cells in response to epoxyazadiradione. We have also analyzed the effect of epoxyazadiradione on breast tumor growth using in vivo mice model.

Results

In this study, we for the first time investigated that out of 10 major limonoids isolated from Azadirachta indica, epoxyazadiradione exhibits most potent anti-cancer activity in both TNBC and ER+ breast cancer cells. Epoxyazadiradione induces apoptosis and inhibits PI3K/Akt-mediated mitochondrial potential, cell viability, migration and angiogenesis. It also inhibits the expression of pro-angiogenic and pro-metastatic genes such as Cox2, OPN, VEGF and MMP-9 in these cells. Furthermore, epoxyazadiradione attenuates PI3K/Akt-mediated AP-1 activation. Our in vivo data revealed that epoxyazadiradione suppresses breast tumor growth and angiogenesis in orthotopic NOD/SCID mice model.

Conclusion

Our findings demonstrate that epoxyazadiradione inhibits PI3K/Akt-dependent mitochondrial depolarisation, induces apoptosis and attenuates cell migration, angiogenesis and breast tumor growth suggesting that this compound may act as a potent therapeutic agent for the management of breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3876-2) contains supplementary material, which is available to authorized users.

Ongoing unmet needs in treating estrogen receptor-positive/HER2-negative metastatic breast cancer

Estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2 negative (HER2-) advanced or metastatic breast cancer (MBC) is the most common MBC subtype and currently remains incurable, with a median overall survival of 24.8 months (95% confidence interval, 21.3-30.3). Common sites of metastases are bone, viscera, and brain, causing significant symptoms that negatively affect patient functioning, quality of life (QoL), and work productivity. Guidelines state that endocrine therapy (ET) is preferable to chemotherapy as first-line treatment for patients with ER+ MBC, regardless of limited visceral metastases, unless rapid tumor response is required or ET resistance is suspected. Although response rates up to 40% have been reported for first-line MBC treatment, the majority of initial responders eventually develop ET resistance. Notwithstanding the steep decline in efficacy between first and later lines of ET, some patients may receive chemotherapy earlier than necessary. Although new treatments have been approved for patients with ER+/HER2- advanced or MBC in the past decade, neither survival nor QoL appear to have improved significantly. Thus, there remain significant unmet needs for this patient population, including improved survival, maintaining or improving patient QoL, and emphasizing the importance of treatment selection to assist healthcare practitioners managing patient care. In this review, we identify current challenges and unmet needs in this patient population, review cutting-edge treatments, and provide clinically relevant suggestions for treatment selection that can optimize outcomes and patients' health-related QoL.

Systematic Literature Review of the Impact of Endocrine Monotherapy and in Combination with Targeted Therapy on Quality of Life of Postmenopausal Women with HR+/HER2- Advanced Breast Cancer

INTRODUCTION

A major treatment goal for advanced breast cancer (ABC) is to maintain or ideally improve patient quality of life (QoL). Given the changing disease landscape, this systematic literature review (SLR) aims to assess the impact of endocrine therapies (ET), including ET monotherapy (ET mono) and ET combined with targeted therapy (ET + TT), on QoL of women with HR+/HER2- ABC.

METHODS

A SLR was conducted to identify randomized controlled trials (RCTs) meeting the following criteria: (1) included ET mono or ET + TT, (2) reported QoL outcomes, (3) focused on women with HR+/HER2- ABC, and (4) published after 2007 (when standardized HER2 testing became available). The databases searched included MEDLINE, EMBASE, Cochrane Library, and key conference proceedings from 2013 to 2016. QoL outcomes for ET mono, ET + TT, and comparisons between the two were summarized from the identified trials.

RESULTS

A total of 11 studies (representing 6 RCTs) were identified. The study populations included first-line (5 studies) and ET-failure settings (6 studies). Across settings, global health status (GHS) maintained or deteriorated slightly on these treatments during the trial period. Time to deterioration (TTD) in QoL measured by GHS was analyzed in 6 studies and 4 RCTs. In the first-line setting, reported median TTD in GHS was similar between ET mono and ET + TT (7.2-13.8 months in ET mono; 11.1 months in ET + TT). In the ET-failure setting, ET + TT showed significantly longer TTD vs. ET mono in GHS (median 5.6-8.4 months in ET mono and 8.3-11.7 months in ET + TT) and some additional domains.

CONCLUSIONS

ET + TT users experienced similar QoL in the first-line and ET-failure setting relative to patients on ET mono. Moreover, ET + TT users experienced better QoL outcomes in some domains in the ET-failure setting relative to ET mono users.

FUNDING

Novartis.

PTK6 regulates growth and survival of endocrine therapy-resistant ER+ breast cancer cells

The non-receptor tyrosine kinase, PTK6/BRK, is highly expressed in multiple tumor types, including prostate, ovarian, and breast cancers, and regulates oncogenic phenotypes such as proliferation, migration, and survival. PTK6 inhibition also overcomes targeted therapy resistance of HER2+ breast cancer. Although PTK6 is highly expressed in ER+ Luminal breast cancers, the role of PTK6 in this subtype has not been elucidated. In this study, we investigated the functions of PTK6 in ER+ Luminal breast cancer cells, including those that are relatively resistant to estrogen deprivation or targeted endocrine therapies used in the treatment of ER+ cancers. Enhanced expression of PTK6 in ER+ breast cancer cells enhances growth of ER+ breast cancer cells, including tamoxifen-treated cells. Downregulation of PTK6 in ER+ breast cancer cells, including those resistant to tamoxifen, fulvestrant, and estrogen deprivation, induces apoptosis, as evidenced by increased levels of cleaved PARP, and an increase in the AnnexinV+ population. PTK6 downregulation impairs growth of these cells in 3D Matrigel^TM cultures, and virtually abrogates primary tumor growth of both tamoxifen-sensitive and resistant MCF-7 xenografts. Finally, we show that p38 MAPK activation is critical for PTK6 downregulation-induced apoptosis, a mechanism that we previously reported for survival of HER2+ breast cancer cells, highlighting conserved mechanisms of survival regulation by PTK6 across breast cancer subtypes. In conclusion, our studies elucidate critical functions of PTK6 in ER+ Luminal breast cancers and support PTK6 as an attractive therapeutic target for ER+ breast cancers.

Drugs that target a tumor-promoting enzyme called protein tyrosine kinase 6 (PTK6) could help treat hormone-receptor positive breast cancer. A team led by Hanna Irie from the Icahn School of Medicine at Mount Sinai in New York, NY, USA, investigated the role of PTK6, also known as breast tumor kinase, in breast cancer cells that grow in response to the hormone estrogen. They boosted the enzyme’s expression in estrogen receptor-expressing breast cancer cells and saw enhanced growth. Conversely, downregulating PTK6 levels led to cell death, including in tumor cells that were resistant to tamoxifen
 and other therapies commonly used to treat estrogen-receptor positive breast cancer. The researchers showed that this effect was dependent on the activation of a signaling pathway previously found to be important in another subtype of breast cancer, highlighting a conserved mechanism of cell survival regulation by PTK6.

Treatment Patterns and Outcomes of Patients With Metastatic ER+/HER-2- Breast Cancer: A Multicountry Retrospective Medical Record Review

PURPOSE

To describe treatment patterns and clinical outcomes among postmenopausal women with metastatic ER⁺/HER-2^- breast cancer treated with ≥ 2 lines of endocrine therapy or chemotherapy in the metastatic setting.

PATIENTS AND METHODS

Retrospective medical record review was conducted in Canada, the United Kingdom, Belgium, the Netherlands, Germany, Spain, and France. Baseline characteristics were assessed at the date of metastatic diagnosis. Time to progression (TTP) and overall survival (OS) were estimated by Kaplan-Meier analyses. Multivariable models were used to evaluate factors associated with disease progression.

RESULTS

Among 901 patients, the mean (standard deviation) age at metastatic diagnosis was 62.7 (9.7) years; 67.26% were initially diagnosed with metastatic disease, 66.37% had visceral disease, and 25.86% had bone metastasis only. Two-thirds of patients received endocrine therapy for first-line treatment. Fifty-nine percent received endocrine therapy, and 37.18% received chemotherapy for second-line treatment. The most common reason for stopping treatment was disease progression. Median (95% confidence interval [CI]) TTP on first-line endocrine treatment was 11.3 (10.7-12.2) months and 7.0 (6.3-7.9) months on chemotherapy. Median (95% CI) TTP on second-line endocrine therapy was 8.1 (7.5-9.1) months and 6.1 (5.4-6.8) months on chemotherapy. Median (95% CI) OS was 68.6 (52.2-83.7) months after first-line endocrine therapy and 39.7 (34.5-48.7) months after chemotherapy.

CONCLUSION

Patients prescribed endocrine therapy had longer TTP and OS than patients prescribed chemotherapy in the first- and second-line settings. Disease progression was less than a year regardless of treatment type and line of therapy, indicating a need for treatments that delay progression without affecting quality of life among these patients.

Spatial intratumoural heterogeneity in the expression of GIT1 is associated with poor prognostic outcome in oestrogen receptor positive breast cancer patients with synchronous lymph node metastases

Background: The outcome for oestrogen receptor positive (ER+) breast cancer patients has improved greatly in recent years largely due to targeted therapy. However, the presence of involved multiple synchronous lymph nodes remains associated with a poor outcome. Consequently, these patients would benefit from the identification of new prognostic biomarkers and therapeutic targets. The expression of G-protein-coupled receptor kinase-interacting protein 1 (GIT1) has recently been shown to be an indicator of advanced stage breast cancer. Therefore, we investigated its expression and prognostic value of GIT1 in a cohort of 140 ER+ breast cancer with synchronous lymph node involvement.

Methods: Immunohistochemistry was employed to assess GIT1 expression in a tissue microarray (TMA) containing duplicate non-adjacent cores with matched primary tumour and lymph node tissue (n=140). GIT1 expression in tumour cells was scored and statistical correlation analyses were carried out.

Results: The results revealed a sub-group of patients that displayed discordant expression of GIT1 between the primary tumour and the lymph nodes (i.e. spatial intratumoural heterogeneity). We observed that loss of GIT1 expression in the tumour cells of the metastasis was associated with a shorter time to recurrence, poorer overall survival, and a shorter median survival time. Moreover, multivariate analysis demonstrated that GIT1 expression was an independent prognostic indicator.

Conclusions: GIT1 expression enabled the identification of a sub-class of ER+ patients with lymph node metastasis that have a particularly poor prognostic outcome. We propose that this biomarker could be used to further stratify ER+ breast cancer patients with synchronous lymph node involvement and therefore facilitate adjuvant therapy decision making.

Long-term management of patients with hormone receptor-positive metastatic breast cancer: Concepts for sequential and combination endocrine-based therapies

Treatment options for hormone receptor-positive (HR-positive) metastatic breast cancer (MBC) continue to increase in parallel with expanding knowledge about the complex biology of breast cancer subtypes and resistance mechanisms to endocrine therapy. For patients with HR-positive MBC, there are now an unprecedented number of endocrine-based treatment options that can improve long-term outcomes, while preserving or optimizing quality of life, and that can be used before selecting more cytotoxic chemotherapeutic regimens. In addition to antiestrogens, steroidal and nonsteroidal aromatase inhibitors, the selective estrogen-receptor degrader, fulvestrant, and new endocrine-based combinations provide significant and clinically meaningful improvements in outcomes in the first line setting and beyond. Also, new clinical scenarios and indications for monotherapy endocrine and targeted therapies continue to be explored. Patients have several therapeutic options when their disease progresses or becomes resistant, although the optimal sequencing of these therapies remains unclear. Ongoing research in the resistant/refractory setting is anticipated to continue improving the outlook for these patients. This review will discuss current and investigational approaches to sequential single-agent endocrine and endocrine-based combination therapy for the long-term management of patients with HR-positive, human epidermal growth factor receptor 2-negative MBC.

Treatment patterns and real world clinical outcomes in ER+/HER2- post-menopausal metastatic breast cancer patients in the United States

Background

With several new therapies becoming available, treatment of metastatic breast cancer (mBC) is evolving. The objective of this study is to describe patient characteristics, treatment patterns and real-world clinical outcomes in post-menopausal women with ER+, HER2- mBC and to obtain insight into patient outcomes and potential unmet needs with current therapies.

Methods

The current study is a physician survey followed by a retrospective chart review of patient medical records by physicians in the US between March and April 2015. One hundred three physicians were asked to complete an online survey aiming to understand their satisfaction and expectations with current available treatments and potential areas of unmet need for mBC patients. Medical records from 178 females were extracted for the chart review. Using these data from medical records, patient characteristics and treatment patterns were analyzed descriptively. Time to progression (TTP) on first line, and progression-free survival (PFS) on second and third line of therapy were analyzed using the Kaplan-Meier method.

Results

Sixty-seven percent (n = 119) of patients had metastatic disease at initial diagnosis of breast cancer. Mean age at chart data extraction was 65.8 (SD: 9.4) years. Aromatase inhibitors (AIs) were prescribed for 58% and around 13% of patients in first line and second line, respectively. Chemotherapy was prescribed to 14% in first line and 31% in second line. Median TTP on first line therapy was 12 months for patients receiving AIs as compared to 7.9 months for patients receiving chemotherapy. Across all treatment lines, bone pain and fatigue were reported as the main symptoms associated with disease progression which had an impact on patient quality of life. Physicians expressed that prolonging life was deemed the most important treatment goal, followed by preservation or improvement of quality of life.

Conclusion

In this study the majority of patients received endocrine therapy as first line treatment and current therapies still resulted in a short time to progression in first line. Results from the chart review and the physician survey highlight a quantitative unmet need for more effective treatments which delay disease progression and improve survival outcomes while maintaining quality of life.

IL4 Primes the Dynamics of Breast Cancer Progression via DUSP4 Inhibition

The tumor microenvironment supplies proinflammatory cytokines favoring a permissive milieu for cancer cell growth and invasive behavior. Here we show how breast cancer progression is facilitated by IL4 secreted by adipose tissue and estrogen receptor-positive and triple-negative breast cancer cell types. Blocking autocrine and paracrine IL4 signaling with the IL4Rα antagonist IL4DM compromised breast cancer cell proliferation, invasion, and tumor growth by downregulating MAPK pathway activity. IL4DM reduced numbers of CD44⁺/CD24^- cancer stem-like cells and elevated expression of the dual specificity phosphatase DUSP4 by inhibiting NF-κB. Enforced expression of DUSP4 drove conversion of metastatic cells to nonmetastatic cells. Mechanistically, RNAi-mediated attenuation of DUSP4 activated the ERK and p38 MAPK pathways, increased stem-like properties, and spawned metastatic capacity. Targeting IL4 signaling sensitized breast cancer cells to anticancer therapy and strengthened immune responses by enhancing the number of IFNγ-positive CTLs. Our results showed the role of IL4 in promoting breast cancer aggressiveness and how its targeting may improve the efficacy of current therapies. Cancer Res; 77(12); 3268-79. ©2017 AACR.

The enigmatic role of RUNX1 in female-related cancers - current knowledge & future perspectives

Historically associated with the aetiology of human leukaemia, the runt-related transcription factor 1 (RUNX1) gene has in recent years reared its head in an assortment of epithelial cancers. This review discusses the state-of-the-art knowledge of the enigmatic role played by RUNX1 in female-related cancers of the breast, the uterus and the ovary. The weight of evidence accumulated so far is indicative of a very context-dependent role, as either an oncogene or a tumour suppressor. This is corroborated by high-throughput sequencing endeavours which report different genetic alterations affecting the gene, including amplification, deep deletion and mutations. Herein, we attempt to dissect that contextual role by firstly giving an overview of what is currently known about RUNX1 function in these specific tumour types, and secondly by delving into connections between this transcription factor and the physiology of these female tissues. In doing so, RUNX1 emerges not only as a gene involved in female sex development but also as a crucial mediator of female hormone signalling. In view of RUNX1 now being listed as a driver gene, we believe that greater knowledge of the mechanisms underlying its functional dualism in epithelial cancers is worthy of further investigation.

Targeted therapies in breast cancer: New challenges to fight against resistance

Breast cancer is the most common type of cancer found in women and today represents a significant challenge to public health. With the latest breakthroughs in molecular biology and immunotherapy, very specific targeted therapies have been tailored to the specific pathophysiology of different types of breast cancers. These recent developments have contributed to a more efficient and specific treatment protocol in breast cancer patients. However, the main challenge to be further investigated still remains the emergence of therapeutic resistance mechanisms, which develop soon after the onset of therapy and need urgent attention and further elucidation. What are the recent emerging molecular resistance mechanisms in breast cancer targeted therapy and what are the best strategies to apply in order to circumvent this important obstacle? The main scope of this review is to provide a thorough update of recent developments in the field and discuss future prospects for preventing resistance mechanisms in the quest to increase overall survival of patients suffering from the disease.

Clinical Implications of ESR1 Mutations in Hormone Receptor-Positive Advanced Breast Cancer

Hormone receptor-positive breast cancer is the most frequent breast cancer subtype. Endocrine therapy (ET) targeting the estrogen receptor (ER) pathway represents the main initial therapeutic approach. The major strategies include estrogen deprivation and the use of selective estrogen modulators or degraders, which show efficacy in the management of metastatic and early-stage disease. However, clinical resistance associated with progression of disease remains a significant therapeutic challenge. Mutations of the ESR1 gene, which encodes the ER, have been increasingly recognized as an important mechanism of ET resistance, with a prevalence that ranges from 11 to 39%. The majority of these mutations are located within the ligand-binding domain and result in an estrogen-independent constitutive activation of the ER and, therefore, resistance to estrogen deprivation therapy such as aromatase inhibition. ESR1 mutations, most often detected from liquid biopsies, have been consistently associated with a worse outcome and are being currently evaluated as a potential biomarker to guide therapeutic decisions. At the same time, targeted therapy directed to ESR1-mutated clones is an appealing concept with preclinical and clinical work in progress.

Advances in Circulating Tumor DNA Analysis

The analysis of cell-free circulating tumor DNA (ctDNA) is a very promising tool and might revolutionize cancer care with respect to early detection, identification of minimal residual disease, assessment of treatment response, and monitoring tumor evolution. ctDNA analysis, often referred to as "liquid biopsy" offers what tissue biopsies cannot-a continuous monitoring of tumor-specific changes during the entire course of the disease. Owing to technological improvements, efforts for the establishment of preanalytical and analytical benchmark, and the inclusion of ctDNA analyses in clinical trial, an actual clinical implementation has come within easy reach. In this chapter, recent advances of the analysis of ctDNA are summarized starting from the discovery of cell-free DNA, to methodological approaches and the clinical applicability.

The Human Kinome Targeted by FDA Approved Multi-Target Drugs and Combination Products: A Comparative Study from the Drug-Target Interaction Network Perspective

The human kinome is one of the most productive classes of drug target, and there is emerging necessity for treating complex diseases by means of polypharmacology (multi-target drugs and combination products). However, the advantages of the multi-target drugs and the combination products are still under debate. A comparative analysis between FDA approved multi-target drugs and combination products, targeting the human kinome, was conducted by mapping targets onto the phylogenetic tree of the human kinome. The approach of network medicine illustrating the drug-target interactions was applied to identify popular targets of multi-target drugs and combination products. As identified, the multi-target drugs tended to inhibit target pairs in the human kinome, especially the receptor tyrosine kinase family, while the combination products were able to against targets of distant homology relationship. This finding asked for choosing the combination products as a better solution for designing drugs aiming at targets of distant homology relationship. Moreover, sub-networks of drug-target interactions in specific disease were generated, and mechanisms shared by multi-target drugs and combination products were identified. In conclusion, this study performed an analysis between approved multi-target drugs and combination products against the human kinome, which could assist the discovery of next generation polypharmacology.

Molecular Markers and Targeted Therapeutics in Metastatic Tumors of the Spine: Changing the Treatment Paradigms

STUDY TYPE

A review of the literature.

OBJECTIVE

The aim of this study was to discuss the evolution of molecular signatures and the history and development of targeted therapeutics in metastatic tumor types affecting the spinal column.

SUMMARY OF BACKGROUND DATA

Molecular characterization of metastatic spine tumors is expected to usher in a revolution in diagnostic and treatment paradigms. Molecular characterization will provide critical information that can be used for initial diagnosis, prognosticating the ideal treatment strategy, assessment of treatment efficacy, surveillance and monitoring recurrence, and predicting complications, clinical outcome, and overall survival in patients diagnosed with metastatic cancers to the spinal column.

METHODS

A review of the literature was performed focusing on illustrative examples of the role that molecular-based therapeutics have played in clinical outcomes for patients diagnosed with metastatic tumor types affecting the spinal column.

RESULTS

The impact of molecular therapeutics including receptor tyrosine kinases and immune checkpoint inhibitors and the ability of molecular signatures to provide prognostic information are discussed in metastatic breast cancer, lung cancer, prostate cancer, melanoma, and renal cell cancer affecting the spinal column.

CONCLUSION

For the providers who will ultimately counsel patients diagnosed with metastases to the spinal column, molecular advancements will radically alter the management/surgical paradigms utilized. Ultimately, the translation of these molecular advancements into routine clinical care will greatly improve the quality and quantity of life for patients diagnosed with spinal malignancies and provide better overall outcomes and counseling for treating physicians.

LEVEL OF EVIDENCE

N/A.

Suppression of Her2/Neu mammary tumor development in mda-7/IL-24 transgenic mice

Melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24) encodes a tumor suppressor gene implicated in the growth of various tumor types including breast cancer. We previously demonstrated that recombinant adenovirus-mediated mda-7/IL-24 expression in the mammary glands of carcinogen-treated (methylnitrosourea, MNU) rats suppressed mammary tumor development. Since most MNU-induced tumors in rats contain activating mutations in Ha-ras, which arenot frequently detected in humans, we presently examined the effect of MDA-7/IL-24 on Her2/Neu-induced mammary tumors, in which the RAS pathway is induced. We generated tet-inducible MDA-7/IL-24 transgenic mice and crossed them with Her2/Neu transgenic mice. Triple compound transgenic mice treated with doxycycline exhibited a strong inhibition of tumor development, demonstrating tumor suppressor activity by MDA-7/IL-24 in immune-competent mice. MDA-7/IL-24 induction also inhibited growth of tumors generated following injection of Her2/Neu tumor cells isolated from triple compound transgenic mice that had not been treated with doxycycline, into the mammary fat pads of isogenic FVB mice. Despite initial growth suppression, tumors in triple compound transgenic mice lost mda-7/IL-24 expression and grew, albeit after longer latency, indicating that continuous presence of this cytokine within tumor microenvironment is crucial to sustain tumor inhibitory activity. Mechanistically, MDA-7/IL-24 exerted its tumor suppression effect on HER2⁺ breast cancer cells, at least in part, through PERP, a member of PMP-22 family with growth arrest and apoptosis-inducing capacity. Overall, our results establish mda-7/IL-24 as a suppressor of mammary tumor development and provide a rationale for using this cytokine in the prevention/treatment of human breast cancer.

GGNBP2 acts as a tumor suppressor by inhibiting estrogen receptor α activity in breast cancer cells

Gametogenetin-binding protein 2 (GGNBP2) is encoded in human chromosome 17q12-q23, a region known as a breast and ovarian cancer susceptibility locus. GGNBP2, also referred to ZFP403, has a single C2H2 zinc finger and a consensus LxxLL nuclear receptor-binding motif. Here, we demonstrate that GGNBP2 expression is reduced in primary human breast tumors and in breast cancer cell lines, including T47D, MCF-7, LCC9, LY2, and MDA-MB-231 compared with normal, immortalized estrogen receptor α (ERα) negative MCF-10A and MCF10F breast epithelial cells. Overexpression of GGNBP2 inhibits the proliferation of T47D and MCF-7 ERα positive breast cancer cells without affecting MCF-10A and MCF10F. Stable GGNBP2 overexpression in T47D cells inhibits 17β-estradiol (E2)-stimulated proliferation as well as migration, invasion, anchorage-independent growth in vitro, and xenograft tumor growth in mice. We further demonstrate that GGNBP2 protein physically interacts with ERα, inhibits E2-induced activation of estrogen response element-driven reporter activity, and attenuates ER target gene expression in T47D cells. In summary, our in vitro and in vivo findings suggest that GGNBP2 is a novel breast cancer tumor suppressor functioning as a nuclear receptor corepressor to inhibit ERα activity and tumorigenesis.

Using the neoadjuvant chemotherapy paradigm to develop precision therapy for muscle-invasive bladder cancer

BACKGROUND

Bladder cancer is a leading cause of morbidity and mortality. Despite recent advances in understanding its molecular biology, the 5-year survival for muscle-invasive disease (muscle-invasive bladder cancer [MIBC]) remains approximately 50%. Although neoadjuvant chemotherapy (NAC) offers an established 5% absolute survival benefit at 5 years, only the 40% of patients with a major tumor response appear to benefit. There remains, therefore, a critical unmet need for predictive markers to determine which patients are best managed with NAC, as well as for novel targeted therapies to overcome resistance to NAC.

METHODS

The NAC paradigm offers the optimal clinical context for developing precision therapy for MIBC. Abundant tissue is available for analysis before NAC in all patients and after NAC in patients with residual MIBC. Technologic advances have enabled next-generation sequencing and gene expression microarray analysis of routinely collected and even archived tissue specimens. These technologies provide a foundation for the identification of markers of chemoresistance and for the development of rational cotargeting strategies.

RESULTS

Modern computational methods allow for some measure of target validation, which can be enhanced by the use of patient-derived primary xenografts (PDX). These PDX can be established at the time of radical cystectomy after NAC if there is residual MIBC. By the time a patient recurs clinically, candidate drugs targeting specific molecular changes in the patient tumor and corresponding PDX would have been tested in the PDX model, and only the most efficacious drug(s) would be administered to the patient. Liquid biopsies in the form of circulating tumor DNA and circulating tumor cells allow noninvasive longitudinal monitoring of the molecular landscape of an advanced tumor as it is being treated with successive courses of systemic therapy.

CONCLUSIONS

These tools combined form the foundation of an evidence-based precision oncology strategy for MIBC.

Profile of palbociclib in the treatment of metastatic breast cancer

Breast cancer is the most common cancer diagnosed in women. Each year, thousands die either because of disease progression or failure of treatment. Breast cancer is classified into different subtypes based on the molecular expression of estrogen receptor (ER), progesterone receptor, and/or human epidermal growth factor receptor 2 (HER2). These receptors represent important therapeutic targets either through monoclonal antibodies or through small-molecule inhibitors directed toward them. However, up to 40% of patients develop either a primary or a secondary resistance to the current treatments. Therefore, there is an urgent need for investigating new targets in order to overcome the resistance and/or enhance the current therapies. Cell cycle is altered in many human cancers, especially in breast cancer. Cyclin-dependent kinases (CDKs), especially CDK4 and CDK6, play a pivotal role in cell cycle progression that makes them potential targets for new promising therapies. CDK inhibition has shown strong antitumor activities, ranging from cytostatic antiproliferative effects to synergistic effects in combination with other antitumor drugs. In order to overcome the drawbacks of the first-generation CDK inhibitors, recently, new CDK inhibitors have emerged that are more selective to CDK4 and CDK6 such as palbociclib, which is the most advanced CDK4/6 inhibitor in trials. In preclinical studies, palbociclib has shown a very promising antitumor activity, especially against ERα+ breast cancer subtype. Palbociclib has gained world attention, and US the Food and Drug Administration has accelerated its approval for first-line treatment in combination with letrozole for the first-line systematic treatment of postmenopausal women with ERα+/HER2− locally advanced or metastatic breast cancer. In this review, we discuss the potential role of CDK inhibition in breast cancer treatment, and focus on palbociclib progress from preclinical studies to clinical trials with mentioning the most recent ongoing as well as planned Phase II and Phase III trials of palbociclib in advanced breast cancer.

The therapeutic potential of mTOR inhibitors in breast cancer

Rapamycin and modified rapamycins (rapalogs) have been used to prevent allograft rejection after organ transplant for over 15 years. The mechanistic target of rapamycin (mTOR) has been determined to be a key component of the mTORC1 complex which consists of the serine/threonine kinase TOR and at least five other proteins which are involved in regulating its activity. Some of the best characterized substrates of mTORC1 are proteins which are key kinases involved in the regulation of cell growth (e.g., p70S6K) and protein translation (e.g., 4E-BP1). These proteins may in some cases serve as indicators to sensitivity to rapamycin-related therapies. Dysregulation of mTORC1 activity frequently occurs due to mutations at, or amplifications of, upstream growth factor receptors (e.g., human epidermal growth factor receptor-2, HER2) as well as kinases (e.g., PI3K) and phosphatases (e.g., PTEN) critical in the regulation of cell growth. More recently, it has been shown that certain rapalogs may enhance the effectiveness of hormonal-based therapies for breast cancer patients who have become resistant to endocrine therapy. The combined treatment of certain rapalogs (e.g., everolimus) and aromatase inhibitors (e.g., exemestane) has been approved by the United States Food and Drug Administration (US FDA) and other drug regulatory agencies to treat estrogen receptor positive (ER+) breast cancer patients who have become resistant to hormonal-based therapies and have progressed. This review will summarize recent basic and clinical research in the area and evaluate potential novel therapeutic approaches.