The importance of distant metastases in hormone-sensitive breast cancer

Liquid biopsy markers for early diagnosis of brain metastasis patients with breast cancer by metabolomics

Introduction: Breast cancer is the most common cancer in women and is the second most common cause of cancer related mortality. Metabolomics, the identification of small metabolites, is a technique for determining the amount of these metabolites. Objectives: This study aimed to identify markers for the early diagnosis of brain metastasis by metabolomic methods in breast cancer patients. Methods: A total of 88 breast cancer patients with distant metastases were included in the study. The patients were divided into two groups according to their metastasis status: patients with brain metastases and distant metastases without any brain metastases. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-qTOF-MS) and gas chromatography-mass spectrometry (GC-MS) analysis methods were used for metabolomic analyses. Results: 33 of them, 88 patients had brain metastasis, and 55 patients had distant metastases without brain metastasis. A total of 72 and 35 metabolites were identified by the GC-MS and LC-qTOF-MS analysis, respectively. 47 of them were found to be significantly different in patients with brain metastasis. The pathway analysis, performed with significantly altered metabolites, showed that aminoacyl tRNA biosynthesis, valine, leucine and isoleucine biosynthesis, alanine, aspartate, and glutamate metabolism, arginine biosynthesis, glycine, serine, and threonine metabolism pathways significantly altered in patients with brain metastasis. Predictive accuracies for have identifying the brain metastasis were performed with receiver operating characteristic (ROC) analysis, and the model with fifteen metabolites has 96.9% accuracy. Conclusions: While these results should be supported by prospective studies, these data are promising for early detection of brain metastasis with markers in liquid biopsy samples.

Acute toxicity evaluation of a novel ceramide analog for the treatment of breast cancer

•

Novel ceramide drug for breast cancer.

•

Toxicological profile was studied.

•

Single dose of 80 mg/kg dose was safe.

•

Single dose of 120 mg/kg caused minor liver and cardiac tissue damage.

We have previously reported that treating triple-negative tumor bearing nude mice with intraperitoneal (ip) 10 mg/kg body weight of (S,E)-3-hydroxy-2-(2-hydroxybenzylidene)amino-N-tetradecylpropanamide, a ceramide analog, 5 days per week for 3 weeks, was shown not only to suppress tumor growth but also to reduce metastasis. Studies reported here focus on determining the toxicity of this drug in the nude mice. During the first study, treated animals (single intraperitoneal (ip) injection, 0, 40, 80 and 120 mg/kg body weight) were closely monitored for 14 days for any signs of illness or death. No mice were lost in any animal groups; however, hepatic serum enzymes were elevated, and hepatic and heart tissue damages were found in the highest dosage group. The subsequent study was performed using a lower dosage range (single ip injection, 0, 25, 50 and 75 mg/kg body weight), which resulted in no significant toxicity. All tested parameters were within normal ranges, with no observed irregularities. Our findings show that a single ip dose of this ceramide analog induced liver and heart toxicity at 120 mg/kg but not at doses of 80 mg/kg body weight or lower.

Cancer Cell-derived Secretory Factors in Breast Cancer-associated Lung Metastasis: Their Mechanism and Future Prospects

In Breast cancer, Lung is the second most common site of metastasis after the bone. Various factors are responsible for Lung metastasis occurring secondary to Breast cancer. Cancer cellderived secretory factors are commonly known as 'Cancer Secretomes'. They exhibit a prompt role in the mechanism of Breast cancer lung metastasis. They are also major constituents of hostassociated tumor microenvironment. Through cross-talk between cancer cells and the extracellular matrix components, cancer cell-derived extracellular matrix components (CCECs) such as hyaluronan, collagens, laminin and fibronectin cause ECM remodeling at the primary site (breast) of cancer. However, at the secondary site (lung), tenascin C, periostin and lysyl oxidase, along with pro-metastatic molecules Coco and GALNT14, contribute to the formation of pre-metastatic niche (PMN) by promoting ECM remodeling and lung metastatic cells colonization. Cancer cell-derived secretory factors by inducing cancer cell proliferation at the primary site, their invasion through the tissues and vessels and early colonization of metastatic cells in the PMN, potentiate the mechanism of Lung metastasis in Breast cancer. On the basis of biochemical structure, these secretory factors are broadly classified into proteins and non-proteins. This is the first review that has highlighted the role of cancer cell-derived secretory factors in Breast cancer Lung metastasis (BCLM). It also enumerates various researches that have been conducted to date in breast cancer cell lines and animal models that depict the prompt role of various types of cancer cell-derived secretory factors involved in the process of Breast cancer lung metastasis. In the future, by therapeutically targeting these cancer driven molecules, this specific type of organ-tropic metastasis in breast cancer can be successfully treated.

Socioeconomic inequalities in metastasis, recurrence, stage and grade of breast cancer: a hospital-based retrospective cohort study

Introduction

This study aims to estimate the Socio-Economic Status (SES) inequality on the metastasis, recurrence, stage and grade in Breast Cancer (BC).

Methods

This retrospective cohort study conducted on 411 BC patients in Arak, Iran. Asset-based questionnaire used to estimate the household SES. For calculate of SES inequality was used from Concentration Index (C). Moreover for investigate the association between recurrence and metastasis with other variables were used from multilevel logistic regression and analysis of variance were used to investigate the relationship between SES and other variables. The data were analyzed with Stata (v.13) software.

Results

Results of analysis of variance showed statistical significant relationship between SES with, insurance, surgery, grade, stage, recurrence and metastasis (p-value < 0.05). Moreover the Odds Ratio (OR) were significant of recurrence with age, academic level of education, supplementary insurance history of BC in first-degree relatives, stage and grade, also, metastasis with age of > 80 years, insurance, supplementary insurance, history of BC in first-degree relatives, chemotherapy, radiotherapy, stage and grade four. The total C index obtained 0.015 (0.002, 0.026), 0.011 (0.003, 0.031), – 0.014 (– 0.034, – 0.001) and – 0.042 (– 0.061, – 0.002) for metastasis, recurrence, stage and grade of BC respectively.

Conclusions

Our results showed evidence of inequality in the metastasis, recurrence, stage and grade in BC patients.

Association between FGFR1 copy numbers, MAP3K1 mutations, and survival in axillary node-positive, hormone receptor-positive, and HER2-negative early breast cancer in the PACS04 and METABRIC studies

PURPOSE

Hormone receptor-positive (HR+) and human epidermal growth factor receptor 2 negative (HER2-) early breast cancer (BC) is the most prevalent BC subtype with substantial biological heterogeneity. Although clinicopathological (CP) characteristics have a clear prognostic value, additional biomarkers could refine survival prediction and guide treatment decision.

METHODS

Copy number aberrations and somatic driver mutations were obtained with OncoScan CGH array and sequencing of 36 genes on HR+/HER2- node-positive early BC patients treated with chemotherapy from the PACS04 trial. We built a two-gene genomic score (GS) associated with distant disease-free survival (DDFS), whose prognostic value was assessed on the external METABRIC data (n = 1413) using overall survival (OS) and breast cancer-specific survival (BCSS).

RESULTS

In the PACS04 trial (n = 327), the median follow-up for DDFS (65 events) was 9.6 years. FGFR1 amplifications ([Formula: see text] = 2.44, 95% CI [1.25; 4.76], p = 0.009) and MAP3K1 mutations ([Formula: see text] = 0.10, [0.01; 0.78], p = 0.03) were associated with DDFS beyond CP characteristics. A prognostic GS combining FGFR1 amplifications and MAP3K1 mutations added more information to CP model ([Formula: see text] = 12.97, [Formula: see text] < 0.001 and [Formula: see text] = 11.52, [Formula: see text] < 0.001). In the METABRIC study (n = 1413), FGFR1 amplifications ([Formula: see text] = 2.00 [1.40; 2.87], p < 0.001) and MAP3K1 mutations ([Formula: see text] = 0.58 [0.41; 0.83], p = 0.003) were significantly associated with BCSS beyond CP characteristics. The prognostic GS added significant prognostic information to CP model ([Formula: see text] = 15.39, [Formula: see text] < 0.001 and [Formula: see text] = 5.62, [Formula: see text] = 0.02).

CONCLUSION

In axillary node-positive, HR+, and HER2- early BC, amplifications of FGFR1 gene were strongly associated with increased risk for distant disease, while mutations of MAP3K1 gene were significantly associated with decreased risk.

Surviving at a distant site: The organotropism of metastatic breast cancer

Many cancers demonstrate a non-random distribution of sites for distant relapse while others have the propensity to metastasize to multiple organ systems. One of the notable recent findings is that the breast cancer subtypes differ not only in their biological characteristics as primary tumors but also in their capacity for metastatic progression. This information could potentially be utilized in treatment decision making and surveillance strategies.

Clinicopathological factors associated with survival in patients with breast cancer brain metastasis

Brain metastasis from breast cancer generally represents a catastrophic event yet demonstrates substantial biological heterogeneity. There have been limited studies solely focusing on the prognosis of patients with such metastasis. In this study, we carried out a comprehensive analysis in 108 consecutive patients with breast cancer brain metastases between 1997 and 2012 to further define clinicopathological factors associated with early onset of brain metastasis and survival outcomes after development of them. We found that lobular carcinoma, higher clinical stages at diagnosis, and lack of coexisting bone metastasis were significantly associated with a worse brain relapse-free survival when compared with brain-only metastasis. High histologic grade, triple-negative breast cancer, and absence of visceral involvement were unfavorable prognostic factors after brain metastasis. Furthermore, high histologic grade, advanced tumor stages, and lack of coexisting bone involvement indicated a worse overall survival. Thus, the previously established prognostic factors in early stage or advanced breast cancers may not entirely apply to patients with brain metastases. Furthermore, the prognostic significance of the clinicopathological factors differed before and after a patient develops brain metastasis. This knowledge might help in establishing an algorithm to further stratify patients with breast cancer into prognostically significant categories for optimal prevention, screening, and treatment of their brain metastasis.

Metastatic Organotropism: An Intrinsic Property of Breast Cancer Molecular Subtypes

It has long been known that some cancers have the propensity to metastasize to certain organs thus creating a nonrandom distribution of sites for distant relapse, a phenomenon known as "metastatic organotropism." Some of these examples include ovary primary to abdominal cavity, prostate primary to bone, and pancreas primary to liver. In contrast, other tumor types, such as mammary and renal cell carcinoma, can relapse in multiple organs although approximately half of advanced breast cancers metastasize to bone. On the other hand gene expression profiling studies have identified various breast cancer classes with prognostic significance. Recent studies have revealed that breast cancer subtypes differ not only in primary tumor characteristics but also in their metastatic behavior. In particular, the luminal tumors are remarkable for their significant bone-seeking phenotype; the HER2 subtype demonstrates a significant liver-homing characteristic; whereas so-called triple-negative breast cancers predispose to lung metastases. These findings suggest that this knowledge could potentially be utilized in the development of effective disease surveillance strategies in the pursuit of precision medicine, thus necessitating further investigation.

Breast carcinoma subtypes show different patterns of metastatic behavior

The aim of our retrospective study was to analyze patterns of subtype specific metastatic spread and to identify the time course of distant metastases. A consecutive series of 490 patients with breast cancer who underwent surgery and postoperative treatment at Semmelweis University, Hungary, and diagnosed between the years 2000 and 2007 was identified from the archives of the 2nd Department of Pathology, Hungary. Molecular subtypes were defined based on the 2011 St. Gallen recommendations. Statistical analysis was performed with SPSS Statistics for Windows, Version 22.0. Distant metastasis free survival (DMFS) was defined as the time elapsed between the first pathological diagnosis of the tumor and the first distant metastasis detection. Distant metastases were detected in 124 patients. Mean time to develop metastasis was 29 months (range 0-127 months). The longest DMFS was observed in the Luminal A (LUMA) subtype (mean 39 months) whereas the shortest was seen in the HER2-positive (HER2+) subtype (mean 21 months; p = 0.012). We confirmed that HER2+ tumors carry a higher risk for distant metastases (42.1%). LUMA-associated metastases were found to be solitary in 59% of cases, whereas HER2+ tumors showed multiple metastases in 79.2% of cases. LUMA tumors showed a preference for bone-only metastasis as compared with HER2+ and triple negative breast cancer (TNBC) cases, which exhibited a higher rate of brain metastasis. The most frequent second metastatic sites of hormone receptor (HR) positive tumors were the lung and liver, whereas the brain was the most affected organ in HR-negative (HR-) cases. Tumor subtypes differ in DMFS and in pattern of distant metastases. HER2+ tumors featured the most aggressive clinical course. Further identification of subtype-specific factors influencing prognosis might have an impact on clinical care and decision-making.

CYC1 Predicts Poor Prognosis in Patients with Breast Cancer

Cytochrome c-1 (CYC1) is an important subunit of mitochondrial complex III. However, its role in tumor progression is unclear. We found that CYC1 was upregulated in breast tumor tissues, especially in tissues with lymph node metastasis. And higher expression of CYC1 correlates with poor prognosis in breast cancer patients using online databases and tools. Then we confirmed that CYC1 contributed to metastasis and proliferation in two highly metastatic human breast cancer cell lines. Digging into the biological function of CYC1, we found the activity of mitochondrial complex III decreased due to silencing CYC1. Then the ratio of AMP to ATP increased and AMPK was activated. Analyzing units of other mitochondrial complexes, we did not find knockdown of CYC1 expression reduced expression of any other unit of OXPHOS. We concluded that CYC1 promoted tumor metastasis via suppressing activation of AMPK and contributed to tumor growth via facilitating production of ATP. Our results indicated that CYC1 plays crucial roles in breast cancer progression and might be a predictive factor assisting future patient diagnosis.

P2Y2R activation by nucleotides released from the highly metastatic breast cancer cell MDA-MB-231 contributes to pre-metastatic niche formation by mediating lysyl oxidase secretion, collagen crosslinking, and monocyte recruitment

Tumor microenvironmental hypoxia induces hypoxia inducible factor-1α (HIF-1α) overexpression, leading to the release of lysyl oxidase (LOX), which crosslinks collagen at distant sites to facilitate environmental changes that allow cancer cells to easily metastasize. Our previous study showed that activation of the P2Y2 receptor (P2Y2R) by ATP released from MDA-MB-231 cells increased MDA-MB-231 cell invasion through endothelial cells. Therefore, in this study, we investigated the role of P2Y2R in breast cancer cell metastasis to distant sites. ATP or UTP released from hypoxia-treated MDA-MB-231 cells induced HIF-1α expression and LOX secretion by the activation of P2Y2R, and this phenomenon was significantly reduced in P2Y2R-depleted MDA-MB-231 cells. Furthermore, P2Y2R-mediated LOX release induced collagen crosslinking in an in vitro model. Finally, nude mice injected with MDA-MB-231 cells showed high levels of LOX secretion, crosslinked collagen and CD11b+ BMDC recruitment in the lung; however, mice that were injected with P2Y2R-depleted MDA-MB-231 cells did not exhibit these changes. These results demonstrate that P2Y2R plays an important role in activation of the HIF-1α-LOX axis, the induction of collagen crosslinking and the recruitment of CD11b+ BMDCs. Furthermore, P2Y2R activation by nucleotides recruits THP-1 monocytes, resulting in primary tumor progression and pre-metastatic niche formation.

Matrix metalloproteinase-1 expression in breast cancer and cancer-adjacent tissues by immunohistochemical staining

Although matrix metalloproteinase-1 (MMP-1) has been considered a factor of crucial importance for breast cancer cells invasion and metastasis, the expression of MMP-1 in different breast cancer and cancer-adjacent tissues have not been fully examined. In the present study, immunohistochemical staining was used to detect the MMP-1 expression in non-specific invasive ductal carcinoma of the breast, cancer-adjacent normal breast tissue, lymph node metastatic non-specific invasive ductal carcinoma of the breast and normal lymph node tissue. The results showed that MMP-1 expression is different in the above tissues. MMP-1 had a positive expression in normal lymph node tissue and lymph node metastatic non-specific invasive ductal carcinoma. The MMP-1 negative expression rate was only 6.1% in non-specific invasive ductal carcinoma of the breast and 2.9% in cancer-adjacent normal breast tissue respectively. MMP-1 expression is higher in non-specific invasive ductal carcinoma and lymph node metastatic non-specific invasive ductal carcinoma compared to cancer-adjacent normal breast tissue and normal lymph node tissue. In conclusion, higher expression of MMP-1 in breast cancer may play a crucial role in promoting breast cancer metastasis.

Risk factors for distant metastasis as a primary site of treatment failure in early-stage breast cancer

The aim of this study was to evaluate the risk factors for distant metastasis (DM) as a primary site of failure in early-stage breast cancer. Data from 294 patients diagnosed with pathologic stage I or II breast cancer between January 2000 and December 2005 were reviewed retrospectively. Median follow-up duration was 81.0 months (range, 18-135 months). The total number of patients with DM without evidence of locoregional recurrence was 20 and the median time between surgery and DM was 29 months (range, 9-79 months). Median survival time was 38 months (range, 22-77 months) after operation. HER-2 positivity (p=0.015), T stage of tumor (p=0.012), and number of involved lymph nodes (p=0.008) were significant predictors of DM in the univariable analysis. Number of involved lymph nodes [p=0.005, hazards ratio (HR): 1.741; 95% confidence interval (CI): 1.178-2.574] and HER-2 positivity (p=0.018, HR: 2.888; 95% CI: 1.201-6.941) had a statistically significant effect on DM-free survival in the multivariable analysis. A cautious evaluation may be helpful when patients with risk factors for DM have symptoms implying the possibility of DM. To reduce DM, applying intensive therapy is needed after curative surgery for patients with high risk for DM.

Exposure to sodium channel-inhibiting drugs and cancer survival: protocol for a cohort study using the QResearch primary care database

INTRODUCTION

Metastasis from solid tumours is associated with significant morbidity and mortality, and is the leading cause of cancer-related deaths. Voltage-gated sodium channels (VGSCs) are drug targets for the treatment of epilepsy. VGSCs are also present in cancer cells, where they regulate metastatic cell behaviours, including cellular movement and invasion. Treating cancer cells with the VGSC-inhibiting anticonvulsant phenytoin reduces cellular invasion and migration. Together, these suggest that VGSCs may be useful targets for inhibiting metastasis. The purpose of this study is to test the hypothesis that use of VGSC-inhibiting drugs will reduce metastasis, and therefore increase survival time in patients with cancer.

METHODS AND ANALYSIS

A cohort study based on primary care data from the QResearch database will include patients with one of the three common tumours: breast, bowel and prostate. The primary outcome will be overall survival from the date of cancer diagnosis. Cox proportional hazards regression will be used to compare the survival of patients with cancer taking VGSC-inhibiting drugs (including anticonvulsants and class I antiarrhythmic agents) with patients with cancer not exposed to these drugs, adjusting for age and sex. Exposure to VGSC-inhibiting drugs will be defined as having at least one prescription for these drugs prior to cancer diagnosis. High and low exposure groups will be identified based on the length of use. A number of sensitivity and secondary analyses will be conducted.

ETHICS AND DISSEMINATION

The protocol has been independently peer-reviewed and approved by the QResearch Scientific Board. The project has also been approved by the University of York Ethical Review Process. The results will be presented at international conferences and published in an open access peer-reviewed journal, in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria.

Voltage-gated sodium channels and metastatic disease

Voltage-gated Na (+) channels (VGSCs) are macromolecular protein complexes containing a pore-forming α subunit and smaller non-pore-forming β subunits. VGSCs are expressed in metastatic cells from a number of cancers. In these cells, Na (+) current carried by α subunits enhances migration, invasion and metastasis in vivo. In contrast, the β subunits mediate cellular adhesion and process extension. The prevailing hypothesis is that VGSCs are upregulated in cancer, in general favoring an invasive/metastatic phenotype, although the mechanisms are still not fully clear. Expression of the Nav 1.5 α subunit associates with poor prognosis in clinical breast cancer specimens, suggesting that VGSCs may have utility as prognostic markers for cancer progression. Furthermore, repurposing existing VGSC-blocking therapeutic drugs may provide a new strategy to improve outcomes in patients suffering from metastatic disease, which is the major cause of cancer-related deaths, and for which there is currently no cure.

Preclinical molecular imaging of the translocator protein (TSPO) in a metastases model based on breast cancer xenografts propagated in the murine brain

Previous studies have demonstrated the feasibility of translocator protein (TSPO) imaging to visualize and quantify human breast adenocarcinoma (MDA-MB-231) cells in vivo using a TSPO-targeted near-infrared (NIR) probe (NIR-conPK11195). This study aimed to extend the use of the TSPO-targeted probe to a more biologically relevant and clinically important tumor microenvironment as well as to assess our ability to longitudinally detect the presence and progression of breast cancer cells in the brain. The in vivo biodistribution and accumulation of NIR-conPK11195 and free (unconjugated) NIR dye were quantitatively evaluated in intracranial MDA-MB-231-bearing mice and non-tumor-bearing control mice longitudinally once a week from two to five weeks post-inoculation. The in vivo time-activity curves illustrate distinct clearance profiles for NIR-conPK11195 and free NIR dye, resulting in preferential accumulation of the TSPO-targeted probe in the intracranial tumor bearing hemisphere (TBH) with significant tumor contrast over normal muscle tissue (p < 0.005 at five weeks; p < 0.01 at four weeks). In addition, the TSPO-labeled TBHs demonstrated significant contrast over the TBHs of mice injected with free NIR dye (p < 0.001 at four and five weeks) as well as over the TSPO-labeled non-tumor-bearing hemispheres (NTBHs) of control mice (p < 0.005 at four and five weeks). Overall, TSPO-targeted molecular imaging appears useful for visualizing and quantifying breast cancer xenografts propagated in the murine brain and may assist in preclinical detection, diagnosis and monitoring of metastatic disease as well as drug discovery. Furthermore, these results indicate it should be possible to perform TSPO-imaging of breast cancer cells in the brain using radiolabeled TSPO-targeted agents, particularly in light of the fact that [11C]-labeled TSPO probes such as [11C]-PK 11195 have been successfully used to image gliomas in the clinic.

Therapeutic potential for phenytoin: targeting Na(v)1.5 sodium channels to reduce migration and invasion in metastatic breast cancer

Voltage-gated Na(+) channels (VGSCs) are heteromeric membrane protein complexes containing pore-forming α subunits and smaller, non-pore-forming β subunits. VGSCs are classically expressed in excitable cells, including neurons and muscle cells, where they mediate action potential firing, neurite outgrowth, pathfinding, and migration. VGSCs are also expressed in metastatic cells from a number of cancers. The Na(v)1.5 α subunit (encoded by SCN5A) is expressed in breast cancer (BCa) cell lines, where it enhances migration and invasion. We studied the expression of SCN5A in BCa array data, and tested the effect of the VGSC-blocking anticonvulsant phenytoin (5,5-diphenylhydantoin) on Na(+) current, migration, and invasion in BCa cells. SCN5A was up-regulated in BCa samples in several datasets, and was more highly expressed in samples from patients who had a recurrence, metastasis, or died within 5 years. SCN5A was also overexpressed as an outlier in a subset of samples, and associated with increased odds of developing metastasis. Phenytoin inhibited transient and persistent Na(+) current recorded from strongly metastatic MDA-MB-231 cells, and this effect was more potent at depolarized holding voltages. It may thus be an effective VGSC-blocking drug in cancer cells, which typically have depolarized membrane potentials. At a concentration within the therapeutic range used to treat epilepsy, phenytoin significantly inhibited the migration and invasion of MDA-MB-231 cells, but had no effect on weakly metastatic MCF-7 cells, which do not express Na(+) currents. We conclude that phenytoin suppresses Na(+) current in VGSC-expressing metastatic BCa cells, thus inhibiting VGSC-dependent migration and invasion. Together, our data support the hypothesis that SCN5A is up-regulated in BCa, favoring an invasive/metastatic phenotype. We therefore propose that repurposing existing VGSC-blocking therapeutic drugs should be further investigated as a potential new strategy to improve patient outcomes in metastatic BCa.

Bisphosphonates: prevention of bone metastases in breast cancer

Disease recurrence and distant metastases remain challenging for patients with breast cancer despite advances in early diagnosis, surgical expertise, and adjuvant therapy. Bone is the most common site for breast cancer metastasis, and the bone microenvironment plays a crucial role in harboring disseminated tumor cells (DTCs), a putative source of late relapse in and outside bone. Therefore, agents that affect bone metabolism might not only prevent the development of bone lesions but also provide meaningful reductions in the risk of relapse both in bone and beyond. Bisphosphonates bind to mineralized bone surfaces and are ingested by osteoclasts, wherein they inhibit osteolysis, thereby preventing the release of growth factors from the bone matrix. Therefore, the bone microenvironment becomes less conducive to survival and growth of DTCs and bone lesion formation. Recent trials of zoledronic acid in the adjuvant setting in breast cancer have demonstrated reduced disease recurrence in bone and other sites in premenopausal and postmenopausal women with early breast cancer. Based on the proven effect of bone protection during adjuvant endocrine therapy, new treatment guidelines recommend the routine use of bisphosphonates to prevent bone loss during adjuvant therapy, which may likely become the standard practice.

Clinical and economic benefits of aromatase inhibitor therapy in early-stage breast cancer

PURPOSE

The clinical and economic benefits of aromatase inhibitor (AI) therapy in early-stage breast cancer are reviewed.

SUMMARY

AI therapy has become a standard of care for the treatment of most postmenopausal women with early-stage breast cancer, as it significantly reduces the risk of disease recurrence and death. Using the currently accepted gold standard for clinical efficacy-improvement in disease-free survival rather than overall survival-exemestane, anastrozole, or letrozole as monotherapy or in sequence with tamoxifen has been found to be superior to tamoxifen monotherapy. Emerging data have demonstrated potential overall survival advantages for AIs subsequent to and directly related to distant recurrence. Of the nonsteroidal AIs, letrozole appears to have the efficacy advantage by demonstrating an early effect on distant recurrence and, subsequently, a potentially significant overall survival benefit, though results of a prospective head-to-head trial of anastrozole and letrozole are not yet available. When the economic burden to society is considered, it appears that all AIs are similarly beneficial on the basis of disease recurrence. However, preliminary analyses indicate that the survival benefit appears to be greater with letrozole than with anastrozole. Thus, considering potential survival benefits and cost-effectiveness, letrozole may be preferable to anastrozole in the early adjuvant setting.

CONCLUSION

AI therapy has become a standard of care for the treatment of most postmenopausal women with early-stage breast cancer. Emerging data have demonstrated potential overall survival advantages for AIs subsequent to and directly related to distant recurrence. When the economic burden to society is considered, it appears that all AIs are similarly beneficial on the basis of disease recurrence.

Use of aromatase inhibitors and bisphosphonates as an anticancer therapy in postmenopausal breast cancer

Breast cancer is a major cause of morbidity and mortality in postmenopausal women worldwide. Reducing the risk of distant disease recurrence is a primary goal of adjuvant endocrine therapy. As we await data from ongoing Phase III comparison trials, an emerging body of evidence demonstrates important differences between third-generation aromatase inhibitors, particularly with respect to potency and prevention of early distant metastases. Furthermore, a growing body of evidence demonstrates anticancer benefits of bisphosphonates in adjuvant breast cancer and other settings. This article outlines the proceedings from an Expert Panel meeting of regionally diverse breast cancer specialists regarding the appropriate use of aromatase inhibitors in postmenopausal hormone-responsive early breast cancer and bisphosphonates as anticancer therapy in adjuvant breast cancer.

Purinergic mechanisms in breast cancer support intravasation, extravasation and angiogenesis

Several advances have recently expanded models of tumor growth and promoted the concept of tumor homeostasis, the hypothesis that primary tumors exert an anti-proliferative effect on both themselves and subclinical secondary metastases. Recent trials indicate that the characterization of tumor growth as uncontrolled is inconsistent with animal models, clinical models, and epidemiological models. There is a growing body of evidence which lends support to an updated concept of tumor growth: tumor homeostasis. In the case of breast cancer, if not all metastasizing tumors, these advances suggest an inconvenient truth. That is, if breast tumor cells metastasize to distant sites early in the tumorigenesis process, then removal of a breast tumor may hasten the development of its metastases. We explore the heretofore unappreciated notion that nucleotides generated by tumor cells following the secretion of an ADP-kinase can promote metastasis and support angiogenesis. Evidence is presented that blockade of the actions of nucleotides in the setting of newly diagnosed breast cancer may provide a useful adjunct to current anti-angiogenesis treatment.

NEDD9 promotes oncogenic signaling in mammary tumor development

In the past 3 years, altered expression of the HEF1/CAS-L/NEDD9 scaffolding protein has emerged as contributing to cancer metastasis in multiple cancer types. However, whereas some studies have identified elevated NEDD9 expression as prometastatic, other work has suggested a negative role in tumor progression. We here show that the Nedd9-null genetic background significantly limits mammary tumor initiation in the MMTV-polyoma virus middle T genetic model. Action of NEDD9 is tumor cell intrinsic, with immune cell infiltration, stroma, and angiogenesis unaffected. The majority of the late-appearing mammary tumors of MMTV-polyoma virus middle T;Nedd9(-/-) mice are characterized by depressed activation of proteins including AKT, Src, FAK, and extracellular signal-regulated kinase, emphasizing an important role of NEDD9 as a scaffolding protein for these prooncogenic proteins. Analysis of cells derived from primary Nedd9(+/+) and Nedd9(-/-) tumors showed persistently reduced FAK activation, attachment, and migration, consistent with a role for NEDD9 activation of FAK in promoting tumor aggressiveness. This study provides the first in vivo evidence of a role for NEDD9 in breast cancer progression and suggests that NEDD9 expression may provide a biomarker for tumor aggressiveness.

Mechanisms of bone metastases of breast cancer

Cancer development is a multi-step process driven by genetic alterations that elicit the progressive transformation of normal human cells into highly malignant derivatives. The altered cell proliferation phenotype of cancer involves a poorly characterized sequence of molecular events, which often result in the development of distant metastasis. In the case of breast cancer, the skeleton is among the most common of metastatic sites. In spite of its clinical importance, the underlying cellular and molecular mechanisms driving bone metastasis remain elusive. Despite advances in our understanding of the phenotype of cancer cells, the increased focus on the contribution of the tumor microenvironment and the recent revival of interest in the role of tumor-propagating cells (so called cancer stem cells) that may originate or be related to normal stem cells produced in the bone marrow, many important questions remain unanswered. As such, a more complete understanding of the influences of both the microenvironment and the tumor phenotype, which impact the entire multi-step metastatic cascade, is required. In this review, the importance of tumor heterogeneity, tumor-propagating cells, the microenvironment of breast cancer metastasis to bone as well as many current endocrine therapies for the prevention and treatment of metastatic breast cancer is discussed.

BMP-6 inhibits microRNA-21 expression in breast cancer through repressing deltaEF1 and AP-1

MicroRNAs (miRNAs), which are small noncoding RNA molecules, play important roles in the post-transcriptional regulation process. The microRNA-21 gene (miR-21) has been reported to be highly expressed in various solid tumors, including breast cancer. Bone morphogenetic protein-6 (BMP-6) has been identified as an inhibitor of breast cancer epithelial-mesenchymal transition (EMT) through rescuing E-cadherin expression. We initiated experiments to identify the relationships between miR-21 and BMP-6 in breast cancer progression. Real-time PCR analysis showed that miR-21 expression was very high in MDA-MB-231 cells that expressed little BMP-6. A reverse correlation between BMP-6 and miR-21 was also determined in breast cancer tissue samples. Moreover, BMP-6 inhibited miR-21 transcription in MDA-MB-231 cells. In order to investigate how BMP-6 inhibited the miR-21 promoter (miPPR-21), we constructed a series of miPPR-21 reporters. Luciferase assay results indicated that BMP-6 inhibited miPPR-21 activity through the E2-box and AP-1-binding sites. We also demonstrated that both deltaEF1 and TPA induced miR-21 expression. Using site-directed mutation and CHIP assay, we found that deltaEF1 induced miPPR-21 activity by binding to the E2-box on miPPR-21. Moreover, TPA triggered miPPR-21 activity through the AP-1 binding sites. BMP-6 treatment significantly reduced the binding of these factors to miPPR-21 by decreasing the expression of deltaEF1 and c-Fos/c-Jun. We also demonstrated that BMP-6-induced downregulation of miR-21 modified the activity of PDCD4 3'UTR and inhibited MDA-MB-231 cell invasion. deltaEF1 overexpression and TPA induction blocked this inhibitory effect of BMP-6. In conclusion, BMP-6-induced inhibition of miR-21 suggests that BMP-6 may function as an anti-metastasis factor by a mechanism involving transcriptional repression of miR-21 in breast cancer.