Tumor stromal vascular endothelial growth factor A is predictive of poor outcome in inflammatory breast cancer

EPAC inhibitor suppresses angiogenesis and tumor growth of triple-negative breast cancer

AIMS

Exchange protein directly activated by cAMP 1 (EPAC1), a major isoform of guanine nucleotide exchange factors, is highly expressed in vascular endothelia cells and regulates angiogenesis in the retina. High intratumor microvascular densities (MVD) resulting from angiogenesis is responsible for breast cancer development. Downregulation of EPAC1 in tumor cell reduces triple-negative breast cancer (TNBC)-induced angiogenesis. However, whether Epac1 expressed in vascular endothelial cells contributes to angiogenesis and tumor development of TNBC remains elusive.

MAIN METHODS

We employed NY0123, a previously identified potent EPAC inhibitor, to explore the anti-angiogenic biological role of EPAC1 in vitro and in vivo through vascular endothelial cells, rat aortic ring, Matrigel plug, and chick embryo chorioallantoic membrane (CAM) and yolk sac membrane (YSM) assays, as well as the in vivo xenograft tumor models of TNBC in both chick embryo and mice.

KEY FINDINGS

Inhibiting EPAC1 in vascular endothelial cells by NY0123 significantly suppresses angiogenesis and tumor growth of TNBC. In addition, NY0123 possesses a better inhibitory efficacy than ESI-09, a reported specific EPAC inhibitor tool compound. Importantly, inhibiting EPAC1 in vascular endothelia cells regulates the typical angiogenic signaling network, which is associated with not only vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor-2 (VEGFR2) signaling, but also PI3K/AKT, MEK/ERK and Notch pathway.

CONCLUSIONS

Our findings support that EPAC1 may serve as an effective anti-angiogenic therapeutic target of TNBC, and EPAC inhibitor NY0123 has the therapeutic potential to be developed for the treatment of TNBC.

Vascular Endothelial Growth Factor Ligands and Receptors in Breast Cancer

Breast cancer (BC) is the most common malignancy responsible for the largest number of deaths in women worldwide. The risk of developing BC is predisposed by many factors such as age, presence of genetic mutations or body weight. The diagnosis is mostly made relatively late, which is why patients are exposed to radical surgical treatments, long-term chemotherapy and lower survival rates. There are no sufficiently sensitive and specific screening tests; therefore, researchers are still looking for new diagnostic biomarkers that would indicate the appearance of neoplastic changes in the initial stage of neoplasm. The VEGF family of proteins (VEGF-A, VEGF-B, VEGF-C, VEGF-D, EG-VEGF, PlGF) and their receptors are significant factors in the pathogenesis of BC. They play a significant role in the process of angiogenesis and lymphangiogenesis in both physiological and pathological conditions. The usefulness of these proteins as potential diagnostic biomarkers has been initially proven. Moreover, the blockage of VEGF-related pathways seems to be a valid therapeutic target. Recent studies have tried to describe novel strategies, including targeting pericytes, use of miRNAs and extracellular tumor-associated vesicles, immunotherapeutic drugs and nanotechnology. This indicates their possible contribution to the formation of breast cancer and their usefulness as potential biomarkers and therapeutic targets.

Diagnostic value of various vascular features of breast cancer by age

BACKGROUND

Tumor angiogenesis plays a critical role in the growth and metastasis of breast cancer. Evaluating the added value of vascular features to Breast Imaging Reporting and Data System (BI-RADS) in differentiating malignant masses from benign ones is essential. Micro-flow Imaging (MFI) is a promising noninvasive diagnostic method for the microvessels in breast tumors, but its precise value is still uncertain.

OBJECTIVES

Understanding whether malignant tumor vascular characteristics by MFI are associated with breast cancer and whether the diagnostic efficiency varies by age.

MATERIALS AND METHODS

B-mode ultrasound and MFI were performed for 153 solid breast lesions. The vessels images by MFI were reviewed and assessed by two investigators, respectively. Then the diagnostic efficacy of different vascular features combined with BI-RADS was evaluated in different age groups.

RESULTS

The mean size of lesions is 19.4 (range 18-78) mm. There were 94 breast masses in benign, while 59 breast masses in malignant by pathology. III Adler classification, penetrating vessels, and complex flow pattern showed a positive association with a high risk of malignant breast lesions (p < 0.05). BI-RADS combined with vessel characteristics show better improvement of diagnostic performance of breast lesions in the elderly group than in the young group.

CONCLUSIONS

Vascular features by MFI contribute to malignant breast masses' diagnosis, and the association might be modified by age.

Anti-Angiogenic Treatments Interact with Steroid Secretion in Inflammatory Breast Cancer Triple Negative Cell Lines

Human inflammatory breast cancer (IBC) is a highly angiogenic disease for which antiangiogenic therapy has demonstrated only a modest response, and the reason for this remains unknown. Thus, the purpose of this study was to determine the influence of different antiangiogenic therapies on in vitro and in vivo steroid hormone and angiogenic growth factor production using canine and human inflammatory breast carcinoma cell lines as well as the possible involvement of sex steroid hormones in angiogenesis. IPC-366 and SUM149 cell lines and xenotransplanted mice were treated with different concentrations of VEGF, SU5416, bevacizumab and celecoxib. Steroid hormone (progesterone, dehydroepiandrostenedione, androstenedione, testosterone, dihydrotestosterone, estrone sulphate and 17β-oestradiol), angiogenic growth factors (VEGF-A, VEGF-C and VEGF-D) and IL-8 determinations in culture media, tumour homogenate and serum samples were assayed by EIA. In vitro, progesterone- and 17β-oestradiol-induced VEGF production promoting cell proliferation and androgens are involved in the formation of vascular-like structures. In vivo, intratumoural testosterone concentrations were augmented and possibly associated with decreased metastatic rates, whereas elevated E1SO4 concentrations could promote tumour progression after antiangiogenic therapies. In conclusion, sex steroid hormones could regulate the production of angiogenic factors. The intratumoural measurement of sex steroids and growth factors may be useful to develop preventive and individualized therapeutic strategies.

Targeting Signaling Pathways in Inflammatory Breast Cancer

Inflammatory breast cancer (IBC), although rare, is the most aggressive type of breast cancer. Only 2-4% of breast cancer cases are classified as IBC, but-owing to its high rate of metastasis and poor prognosis-8% to 10% of breast cancer-related mortality occur in patients with IBC. Currently, IBC-specific targeted therapies are not available, and there is a critical need for novel therapies derived via understanding novel targets. In this review, we summarize the biological functions of critical signaling pathways in the progression of IBC and the preclinical and clinical studies of targeting these pathways in IBC. We also discuss studies of crosstalk between several signaling pathways and the IBC tumor microenvironment.

Expression of Angiogenic Proteins in Tumor and Stroma Affects Survival in Patients With Gastric Cancer

BACKGROUND

Gastric cancer is one of the most frequent malignancies worldwide. Angiogenic growth factors play a crucial role in mediating the crosstalk between cancer cells and the surrounding microenvironment. In this exploratory study, we investigate the impact of angiogenic proteins within the tumor cell or stroma compartment on survival of patients with gastric cancer.

MATERIALS AND METHODS

In 29 patients, tumor and stromal compartments were separated using laser capture microdissection. Angiogenic protein expression was measured using a bead-based immunoassay and correlated with tumor stage and overall survival.

RESULTS

Overall survival was significantly shorter in patients with a high stroma concentration of vascular endothelial growth factor (VEGF)-A (23.5 (±17.6) versus 33.6 (±21.0) mo; P = 0.009) and stem cell factor (22.2 (±18.5) versus 33.6 (±21.8) mo; P = 0.01) compared with patients with a low stroma concentration. High stromal VEGF-D showed a trend toward worse survival (26.8 (±22.0) versus 37.2 (±19.0) mo; P = 0.09). We did not observe any significant correlation between tumor-specific expression of angiogenic cytokines and survival.

CONCLUSIONS

This translational study highlights the difference in clinical impact between tumor and stromal expression of angiogenic proteins. Compartment-specific concentrations of VEGF-A and stem cell factor affect the clinical prognosis and help to identify the best therapy for patients with gastric cancer.

Carpesium abrotanoides (L.) Root as a Potential Source of Natural Anticancer Compounds: Targeting Glucose Metabolism and PKM2/HIF-1α Axis of Breast Cancer Cells

Carpesium abrotanoides L. (CA) is widely used as a medicinal plant in Asia. The biological activities of the extract from the roots of Carpesium abrotanoides L. (PCA) and its major components were analyzed in this study. PCA was separated and identified with mass spectrometry. Furthermore, we sought to elucidate the anticancer activity of PCA and its mechanisms. PCA exerted its anti-breast cancer activity through inhibiting the expression of glycolysis-related genes, such as glucose transporter 1, lactate dehydrogenase A, and hexokinase 2. Moreover, PCA downregulated the expression of pyruvate kinase M2 and altered its cellular translocation. We also demonstrated PCA is an inhibitor of the PKM2/hypoxia-inducible factor-1α axis, indicating that PCA is potentially useful as an anti-breast cancer agent. PRACTICAL APPLICATION: In this study, the extract from roots of Carpesium abrotanoides Linn. (PCA) was shown to have a noticeable anticancer effect against breast cancer in vitro, and PCA exerts the anticancer activity by regulating glucose metabolism and PKM2 expression. These findings indicate that PCA is a promising agent with practical applications in the development of functional food containing Carpesium abrotanoides L. root extracts.

Bradykinin Receptor B1 and C-Reactive Protein as Prognostic Factors for Pharyngocutaneous Fistula Development After Laryngectomy

Pharyngocutaneous fistulae (PCF) are one of the most common complications after laryngectomy. Predisposing risk factors have been studied, yet knowledge to determine which patients are prone to developing a fistula remains scarce. This study aims to establish prognostic parameters to identify individual patients at risk for PCF development. As PCF and inflammation seem to be interwoven, this work focuses on markers able to detect an inflammatory response. We retrospectively analyzed all patients who had undergone a laryngectomy at our clinic in the years 2007 to 2017 (n = 182). Immunohistochemical expression of bradykinin type 1 and 2 receptor and vascular endothelial growth factor receptor 2 was studied in all available tumor samples. Additionally, the clinical inflammation parameters 'body temperature', 'pain', 'c-reactive protein (CRP)', and 'leucocytes' were postoperatively tracked in all patients. The times between fistula diagnosis, therapeutic approach, and hospital discharge were recorded. We found a strong correlation between inflammation and the formation of a fistula. High bradykinin 1 receptor expression in the tumor samples correlated with postoperative PCF development. Persistently elevated CRP and leukocyte levels beyond the 6th postoperative day were also risk factors. A decreased time lapse between PCF diagnosis and surgical revision clearly correlated with a shorter hospital stay. In this study, we identified a bradykinin 1 receptor positive patient group at high risk for development of PCF. We recommend close monitoring for fistula formation in these patients to ensure timely intervention.

Inflammatory breast cancer and chest wall disease: The oncologist perspective

Chest wall inflammatory and lymphangitic breast cancer represents a clinical spectrum and a model disease. Inflammation and the immune response have a role in the natural history of this special clinical presentation. Preclinical models and biomarker studies suggest that inflammatory breast cancer comprises a more important role for the tumour microenvironment, including immune cell infiltration and vasculogenesis, especially lympho-angiogenesis. Across this clinical continuum of the chest wall disease there is an important role of the inflammation cascade. The activation of mature dendritic cells (DCs) through toll like receptors (TLRs) or by inflammatory cytokines converts immature DCs into mature DCs that present specific antigen to T cells, thereby activating them. Maturation of DCs is accompanied by co-stimulatory molecules and secretion of inflammatory cytokines polarizing lymphocytic, macrophages and fibroblast infiltration. It is unknown whether immune cells associated to the IBC microenvironment play a role in this scenario to transiently promote epithelial to mesenchymal transition (EMT) in these cells. Immune and microenvirnment factors can induce phenotypic, morphological, and functional changes in breast cancer cells. We can hypothesize that similar inflammatory conditions in vivo may support both the rapid metastasis and tight tumor emboli that are characteristic of chest wall disease and that targeted anti-inflammatory therapy may play a role in this patient population. The current review will review biological and clinical data of this special condition.

Nuclear factor 90 promotes angiogenesis by regulating HIF-1α/VEGF-A expression through the PI3K/Akt signaling pathway in human cervical cancer

Vascular endothelial growth factor A (VEGF-A), a fundamental component of angiogenesis, provides nutrients and oxygen to solid tumors, and enhances tumor cell survival, invasion, and migration. Nuclear factor 90 (NF90), a double-stranded RNA-binding protein, is strongly expressed in several human cancers, promotes tumor growth by reducing apoptosis, and increasing cell cycle process. The mechanisms by which cervical cancer cells inducing VEGF-A expression and angiogenesis upon NF90 upregulation remain to be fully established. We demonstrated that NF90 is upregulated in human cervical cancer specimens and the expression of NF90 is paralleled with that of VEGF-A under hypoxia. The expressions of hypoxia inducible factor-1α (HIF-1α) and VEGF-A are downregulated upon NF90 knockdown, which can be rescued by ectopic expression of NF90. Suppression of NF90 decreases the tube formation and cell migration of HUVECs. Moreover, the PI3K/Akt signaling pathway participates in the regulation. Knockdown of NF90 also reduces the tumor growth and angiogenesis of cervical cancer cell line in the mouse xenograft model. Taken together, suppression of NF90 in cervical cancer cell lines can decrease VEGF-A expression, inhibit angiogenesis, and reduce tumorigenic capacity in vivo.

Comparative aspects of canine and human inflammatory breast cancer

Inflammatory breast cancer (IBC) in humans is the most aggressive form of mammary gland cancer and shares clinical, pathologic, and molecular patterns of disease with canine inflammatory mammary carcinoma (CIMC). Despite the use of multimodal therapeutic approaches, including targeted therapies, the prognosis for IBC/CIMC remains poor. The aim of this review is to critically analyze IBC and CIMC in terms of biology and clinical features. While rodent cancer models have formed the basis of our understanding of cancer biology, the translation of this knowledge into improved outcomes has been limited. However, it is possible that a comparative "one health" approach to research, using a natural canine model of the disease, may help advance our knowledge on the biology of the disease. This will translate into better clinical outcomes for both species. We propose that CIMC has the potential to be a useful model for developing and testing novel therapies for IBC. Further, this strategy could significantly improve and accelerate the design and establishment of new clinical trials to identify novel and improved therapies for this devastating disease in a more predictable way.

VEGFA links self-renewal and metastasis by inducing Sox2 to repress miR-452, driving Slug

Cancer stem cells (CSC) appear to have increased metastatic potential, but mechanisms underlying this are poorly defined. Here we show that VEGFA induction of Sox2 promotes EMT and tumor metastasis. In breast lines and primary cancer culture, VEGFA rapidly upregulates SOX2 expression, leading to SNAI2 induction, EMT, increased invasion and metastasis. We show Sox2 downregulates miR-452, which acts as a novel metastasis suppressor to directly target the SNAI2 3′-untranslated region (3′-UTR). VEGFA stimulates Sox2- and Slug-dependent cell invasion. VEGFA increases lung metastasis in vivo, and this is abrogated by miR-452 overexpression. Furthermore, SNAI2 transduction rescues metastasis suppression by miR-452. Thus, in addition to its angiogenic action, VEGFA upregulates Sox2 to drive stem cell expansion, together with miR-452 loss and Slug upregulation, providing a novel mechanism whereby cancer stem cells acquire metastatic potential. Prior work showed EMT transcription factor overexpression upregulates CSC. Present work indicates that stemness and metastasis are a two-way street: Sox2, a major mediator of CSC self-renewal, also governs the metastatic process.

ERpS294 is a biomarker of ligand or mutational ERα activation and a breast cancer target for CDK2 inhibition

ERα phosphorylation at hinge site S294 (pS294) was recently shown to be essential for ER-dependent gene transcription and mediated by an unknown cyclin-dependent kinase (CDK). This study was undertaken to identify the exact CDK pathway mediating pS294 formation, and to determine if this phosphorylation event occurs with, and can be targeted to treat, the ligand-independent growth of breast cancers expressing endocrine-refractory ESR1 mutations. Using a newly developed anti-pS294 monoclonal antibody, a combination of CDK specific siRNA knockdown studies and a broad panel of CDK selective inhibitors against ligand (E2)-stimulated MCF7 cells, we first identified CDK2 as the primary mediator of pS294 formation and showed that CDK2-selective inhibitors like Dinaciclib, but not CDK4/6 inhibitors like Palbociclib, can selectively prevent pS294 formation and repress ER-dependent gene expression. We then expressed the ER-activating mutations ERmut(Y537S) and ERmut(D538G) in MCF7 cells, and demonstrated their ability to induce ligand-independent and tamoxifen-resistant growth, associated with constitutive and CDK2-dependent pS294 expression. Following robust growth of E2-independent and TAM-resistant MCF7mutER(Y537S) tumors in vivo, nude mice were also treated with either Dinaciclib or Palbociclib at doses and injection schedules unable to retard tumor growth as single agents; the TAM plus Palbociclib combination arrested further tumor growth without affecting pS294 formation, while the TAM plus Dinaciclib combination produced tumor regression associated with loss of pS294 expression. These findings, and our proposed mechanistic model, provide new rationale for the clinical evaluation of CDK2 inhibitors given in combination with endocrine agents as a new treatment strategy against ESR1 mutation expressing breast cancers.

Application of a Novel Microvascular Imaging Technique in Breast Lesion Evaluation

Conventional power Doppler imaging (PDI) and the novel Superb Microvascular Imaging (SMI) technique were applied to observe the distribution of microvessels in 135 breast lesions, using semi-quantitative grading, penetrating vessel evaluation and flow distribution pattern to evaluate diagnostic efficacy. Compared with PDI, SMI detected more flow signals and details of microvessels. Further, when a centrally distributed branching or diffusing mode was used as a criterion for diagnosing malignancy, SMI improved diagnosis of breast masses. Sensitivity, specificity, positive predictive value and negative predictive value of SMI-assessed flow distribution were 85.4%, 92.6%, 83.3% and 93.5%, respectively, compared with 70.7%, 92.6%, 80.5% and 87.9% for PDI. We also found that flow distribution pattern analysis is superior to semi-quantitative grading and the penetrating vessel method in differentiating malignant breast lesions. Our work here further supports SMI as a novel and promising technique in visualizing microvasculature in breast lesions that may be of paramount use in initial diagnosis as well as follow-up assessment in various treatment regimes.

The crucial role of miR-126 on suppressing progression of esophageal cancer by targeting VEGF-A

Background

miR-126 is a key regulator of oncogenic processes. It is functionally linked to cellular proliferation, survival and migration. Vascular endothelial growth factor A (VEGF-A), which is regarded as a tumorgenesis activator, could directly target miR-126 in several tumors. However, the mechanism in esophageal cancer remains unclear.

Methods and results

In this study, the expression of miR-126 and VEGF-A were assessed in esophageal cancer tissues and esophageal cancer cell lines. We found that miR-126 has significantly lower expression in esophageal cancer tissues and esophageal cancer cell lines than in healthy tissues, while the expression of VEGF-A is high. Luciferase reporter assays were performed to investigate the relationship between VEGF-A and miR-126. We confirmed that VEGF-A is a target for miR-126. Furthermore, the proliferation of esophageal cancer cells with miR-126 overexpression and miR-126 knockdown was monitored using the MTT assay. The results showed that miR-126 could inhibit esophageal cancer cell proliferation in vitro. The effect of miR-126 was also detected in BALB/c nude mice with transplanted esophageal cancer cells. In vivo study showed that tumor growth was significantly suppressed by miR-126 overexpression.

Conclusions

We believe that restoring miR-126 levels may be a promising therapeutic approach in cases of esophageal cancer.

Loss of membranous VEGFR1 expression is associated with an adverse phenotype and shortened survival in breast cancer

Angiogenesis is a key process in tumor growth and progression, which is controlled by vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs). In order to better understand the prevalence and prognostic value of VEGFR1 expression in breast cancer, a tissue microarray containing >2,100 breast cancer specimens, with clinical follow‑up data, was analyzed by immunohistochemistry using an antibody directed against the membrane‑bound full‑length receptor protein. The results demonstrated that membranous VEGFR1 staining was detected in all (5 of 5) normal breast specimens. In carcinoma specimens, membranous staining was negative in 3.1%, weak in 6.3%, moderate in 10.9%, and strong in 79.7% of the 1,630 interpretable tissues. Strong staining was significantly associated with estrogen receptor and progesterone receptor expression, but was inversely associated with advanced tumor stage (P=0.0431), high Bloom-Richardson-Ellis Score for Breast Cancer grade and low Ki67 labeling index (both P<0.0001). Cancers with moderate to strong (high) VEGFR1 expression were associated with significantly improved overall survival, as compared with tumors exhibiting negative or weak (low) expression (P=0.0015). This association was also detected in the subset of nodal‑positive cancers (P=0.0018), and in the subset of 185 patients who had received tamoxifen as the sole therapy (P=0.001). In conclusion, these data indicated that membrane‑bound VEGFR1 is frequently expressed in normal and cancerous breast epithelium. In addition, reduced or lost VEGFR1 expression may serve as a marker for poor prognosis in patients with breast cancer, who might not optimally benefit from endocrine therapy.

Exploring new biomarkers in the tumour microenvironment of canine inflammatory mammary tumours

Human inflammatory breast cancer (IBC) and canine inflammatory mammary cancer (CIMC) are the most aggressive forms of mammary cancer. Current research aims to identify new therapeutic targets. Here, we investigated gene expression levels of biomarkers associated with the inflammatory microenvironment. A total of 32 formalin-fixed paraffin-embedded samples of canine mammary carcinoma (CIMC = 26; non-CIMC = 6) were used and their cDNA subjected to quantitative polymerase chain reaction (qPCR) to establish gene expression levels for mediators commonly implicated in linking carcinogenesis with inflammation. Gene expression differences between CIMC and non-CIMC types were obtained for cyclooxygenase 2 (COX-2) (P = 0.004), synuclein gamma (SNCG) (P = 0.006), tribbles 1 (P = 0.025), vascular endothelial growth factor (VEGF) (P = 0.017) and CSF1R (P = 0.045). Among these biomarkers correlations were found, particularly between SNCG and tribbles 1 (r = 0.512, P = 0.001). The efficient metastasis of CIMC is intimately linked to components in the tumour microenvironment. This study suggests that upregulation and correlation of SNCG and tribbles 1 deserves to be further explored.

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Wnt5A regulates ABCB1 expression in multidrug-resistant cancer cells through activation of the non-canonical PKA/β-catenin pathway

Multidrug resistance in cancer cells arises from altered drug permeability of the cell. We previously reported activation of the Wnt pathway in ABCB1-overexpressed human uterus sarcoma drug-resistant MES-SA/Dx5 cells through active β-catenin and associated transactivation activities, and upregulation of Wnt-targeting genes. In this study, Wnt5A was found to be significantly upregulated in MES-SA/Dx5 and MCF7/ADR2 cells, suggesting an important role for the Wnt5A signaling pathway in cancer drug resistance. Higher cAMP response elements and Tcf/Lef transcription activities were shown in the drug-resistant cancer cells. However, expression of Wnt target genes and CRE activities was downregulated in Wnt5A shRNA stably-transfected MES-SA/Dx5 cells. Cell viability of the drug-resistant cancer cells was also reduced by doxorubicin treatment and Wnt5A shRNA transfection, or by Wnt5A depletion. The in vitro data were supported by immunohistochemical analysis of 24 paired breast cancer biopsies obtained pre- and post-chemotherapeutic treatment. Wnt5A, VEGF and/or ABCB1 were significantly overexpressed after treatment, consistent with clinical chemoresistance. Taken together, the Wnt5A signaling pathway was shown to contribute to regulating the drug-resistance protein ABCB1 and β-catenin-related genes in antagonizing the toxic effects of doxorubicin in the MDR cell lines and in clinical breast cancer samples.

HIF-1α/GPER signaling mediates the expression of VEGF induced by hypoxia in breast cancer associated fibroblasts (CAFs)

INTRODUCTION

Carcinoma-associated fibroblasts (CAFs) play a pivotal role in cancer progression by contributing to invasion, metastasis and angiogenesis. Solid tumors possess a unique microenvironment characterized by local hypoxia, which induces gene expression changes and biological features leading to poor outcomes. Hypoxia Inducible Factor 1 (HIF-1) is the main transcription factor that mediates the cell response to hypoxia through different mechanisms that include the regulation of genes strongly associated with cancer aggressiveness. Among the HIF-1 target genes, the G-protein estrogen receptor (GPER) exerts a stimulatory role in diverse types of cancer cells and in CAFs.

METHODS

We evaluated the regulation and function of the key angiogenic mediator vascular endothelial growth factor (VEGF) in CAFs exposed to hypoxia. Gene expression studies, Western blotting analysis and immunofluorescence experiments were performed in CAFs and breast cancer cells in the presence of cobalt chloride (CoCl₂) or cultured under low oxygen tension (2% O₂), in order to analyze the involvement of the HIF-1α/GPER signaling in the biological responses to hypoxia. We also explored the role of the HIF-1α/GPER transduction pathway in functional assays like tube formation in human umbilical vein endothelial cells (HUVECs) and cell migration in CAFs.

RESULTS

We first determined that hypoxia induces the expression of HIF-1α and GPER in CAFs, then we ascertained that the HIF-1α/GPER signaling is involved in the regulation of VEGF expression in breast cancer cells and in CAFs exposed to hypoxia. We also assessed by ChIP assay that HIF-1α and GPER are both recruited to the VEGF promoter sequence and required for VEGF promoter stimulation upon hypoxic condition. As a biological counterpart of these findings, conditioned medium from hypoxic CAFs promoted tube formation in HUVECs in a HIF-1α/GPER dependent manner. The functional cooperation between HIF-1α and GPER in CAFs was also evidenced in the hypoxia-induced cell migration, which involved a further target of the HIF-1α/GPER signaling like connective tissue growth factor (CTGF).

CONCLUSIONS

The present results provide novel insight into the role elicited by the HIF-1α/GPER transduction pathway in CAFs towards the hypoxia-dependent tumor angiogenesis. Our findings further extend the molecular mechanisms through which the tumor microenvironment may contribute to cancer progression.

Inflammatory breast cancer: an overview

Inflammatory breast cancer (IBC) is the most aggressive entity of breast cancer. Management involves coordination of multidisciplinary management and usually includes neoadjuvant chemotherapy, ablative surgery if a tumor-free resection margin is expected and locoregional radiotherapy. This multimodal therapeutic approach has significantly improved patient survival. However, the median overall survival among women with IBC is still poor. By elucidating the biologic characteristics of IBC, new treatment options may become available. We performed a comprehensive review of the English-language literature on IBC through computerized literature searches. The objective of the current review is to present an overview of the literature related to the biology, imaging and multidisciplinary treatment of inflammatory breast cancer.

Simvastatin radiosensitizes differentiated and stem-like breast cancer cell lines and is associated with improved local control in inflammatory breast cancer patients treated with postmastectomy radiation

Reported rates of local failure after adjuvant radiation for women with inflammatory breast cancer (IBC) and triple-negative non-IBC are higher than those of women with receptor-expressing non-IBC. These high rates of locoregional recurrence are potentially influenced by the contribution of radioresistant cancer stem cells to these cancers. Statins have been shown to target stem cells and improve disease-free survival among IBC patients. We examined simvastatin radiosensitization of multiple subtypes of breast cancer cell lines in vitro in monolayer and mammosphere-based clonogenic assays and examined the therapeutic benefit of statin use on local control after postmastectomy radiation (PMRT) among IBC patients. We found that simvastatin radiosensitizes mammosphere-initiating cells (MICs) of IBC cell lines (MDA-IBC3, SUM149, SUM190) and of the metaplastic, non-IBC triple-negative receptor cell line (SUM159). However, simvastatin radioprotects MICs of non-IBC cell lines MCF-7 and SKBR3. In a retrospective clinical study of 519 IBC patients treated with PMRT, 53 patients used a statin. On univariate analysis, actuarial 3-year local recurrence-free survival (LRFS) was higher among statin users, and on multivariate analysis, triple negative breast cancer, absence of lymphatic invasion, neoadjuvant pathological tumor response to preoperative chemotherapy, and statin use were independently associated with higher LRFS. In conclusion, patients with IBC and triple-negative non-IBC breast cancer have the highest rates of local failure, and there are no available known radiosensitizers. We report significant improvement in local control after PMRT among statin users with IBC and significant radiosensitization across triple-negative and IBC cell lines of multiple subtypes using simvastatin. These data suggest that simvastatin should be justified as a radiosensitizing agent by a prospective clinical trial.

Inhibition of endothelial FAK activity prevents tumor metastasis by enhancing barrier function

Endothelial cell focal adhesion kinase is a key intermediate between c-Src and the regulation of endothelial cell barrier function in the control of tumor metastasis.

Pharmacological focal adhesion kinase (FAK) inhibition prevents tumor growth and metastasis, via actions on both tumor and stromal cells. In this paper, we show that vascular endothelial cadherin (VEC) tyrosine (Y) 658 is a target of FAK in tumor-associated endothelial cells (ECs). Conditional kinase-dead FAK knockin within ECs inhibited recombinant vascular endothelial growth factor (VEGF-A) and tumor-induced VEC-Y658 phosphorylation in vivo. Adherence of VEGF-expressing tumor cells to ECs triggered FAK-dependent VEC-Y658 phosphorylation. Both FAK inhibition and VEC-Y658F mutation within ECs prevented VEGF-initiated paracellular permeability and tumor cell transmigration across EC barriers. In mice, EC FAK inhibition prevented VEGF-dependent tumor cell extravasation and melanoma dermal to lung metastasis without affecting primary tumor growth. As pharmacological c-Src or FAK inhibition prevents VEGF-stimulated c-Src and FAK translocation to EC adherens junctions, but FAK inhibition does not alter c-Src activation, our experiments identify EC FAK as a key intermediate between c-Src and the regulation of EC barrier function controlling tumor metastasis.

Molecular markers for breast cancer: prediction on tumor behavior

Breast cancer is one of the most common cancers with greater than 1,300,000 cases and 450,000 deaths each year worldwide. The development of breast cancer involves a progression through intermediate stages until the invasive carcinoma and finally into metastatic disease. Given the variability in clinical progression, the identification of markers that could predict the tumor behavior is particularly important in breast cancer. The determination of tumor markers is a useful tool for clinical management in cancer patients, assisting in diagnostic, staging, evaluation of therapeutic response, detection of recurrence and metastasis, and development of new treatment modalities. In this context, this review aims to discuss the main tumor markers in breast carcinogenesis. The most well-established breast molecular markers with prognostic and/or therapeutic value like hormone receptors, HER-2 oncogene, Ki-67, and p53 proteins, and the genes for hereditary breast cancer will be presented. Furthermore, this review shows the new molecular targets in breast cancer: CXCR4, caveolin, miRNA, and FOXP3, as promising candidates for future development of effective and targeted therapies, also with lower toxicity.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.