The lymphovascular embolus of inflammatory breast cancer expresses a stem cell-like phenotype

Inflammatory breast cancer: As surgical oncologists, what can we do?

Breast cancer surgery is the primary treatment for early-stage breast cancer. However, inflammatory breast cancer (IBC), with its specific presentation characterized by skin invasion, is unfit for primary surgery. According to the different guidelines, the management of IBC is trimodal with the coordination of oncologists, surgeons, and radiation therapists. Advances in breast cancer imaging and the development of more targeted therapies make new challenges for this aggressive cancer. This chapter aims to provide an update on the role of surgery in IBC. Radical surgery is still considered the standard surgical treatment in IBC. Some authors suggest a conservative surgery in patients with a clinical response to chemotherapy without affecting survival. For lymph node surgery, the sentinel lymph node biopsy (SLNB) is not feasible in IBC patients, according to the existing studies. However, prospective studies on SLNB are needed to verify its reliability after chemotherapy for a specific group of patients. In the metastatic IBC, surgery can be considered if there is a good response after chemotherapy or for uncontrolled symptoms. Existing studies showed that surgery may impact survival for these patients. Prospective studies are mandatory to optimize IBC management, considering factors such as tumor's molecular profile.

Deciphering the molecular biology of inflammatory breast cancer through molecular characterization of patient samples and preclinical models

Inflammatory breast cancer is an aggressive subtype of breast cancer with dismal patient prognosis and a unique clinical presentation. In the past two decades, molecular profiling technologies have been used in order to gain insight into the molecular biology of IBC and to search for possible targets for treatment. Although a gene signature that accurately discriminates between IBC and nIBC patient samples and preclinical models was identified, the overall genomic and transcriptomic differences are small and ambiguous, mainly due to the limited sample sizes of the evaluated patient series and the failure to correct for confounding effects of the molecular subtypes. Nevertheless, data collected over the past 20 years by independent research groups increasingly support the existence of several IBC-specific biological characteristics. In this review, these features are classified as established, emerging and conceptual hallmarks based on the level of evidence reported in the literature. In addition, a synoptic model is proposed that integrates all hallmarks and that can explain how cancer cell intrinsic mechanisms (i.e. NF-κB activation, genomic instability, MYC-addiction, TGF-β resistance, adaptive stress response, chromatin remodeling, epithelial-to-mesenchymal transition) can contribute to the establishment of the dynamic immune microenvironment associated with IBC. It stands to reason that future research projects are needed to further refine (parts of) this model and to investigate its clinical translatability.

TBCRC 039: a phase II study of preoperative ruxolitinib with or without paclitaxel for triple-negative inflammatory breast cancer

BACKGROUND

Patients with inflammatory breast cancer (IBC) have overall poor clinical outcomes, with triple-negative IBC (TN-IBC) being associated with the worst survival, warranting the investigation of novel therapies. Preclinical studies implied that ruxolitinib (RUX), a JAK1/2 inhibitor, may be an effective therapy for TN-IBC.

METHODS

We conducted a randomized phase II study with nested window-of-opportunity in TN-IBC. Treatment-naïve patients received a 7-day run-in of RUX alone or RUX plus paclitaxel (PAC). After the run-in, those who received RUX alone proceeded to neoadjuvant therapy with either RUX + PAC or PAC alone for 12 weeks; those who had received RUX + PAC continued treatment for 12 weeks. All patients subsequently received 4 cycles of doxorubicin plus cyclophosphamide prior to surgery. Research tumor biopsies were performed at baseline (pre-run-in) and after run-in therapy. Tumors were evaluated for phosphorylated STAT3 (pSTAT3) by immunostaining, and a subset was also analyzed by RNA-seq. The primary endpoint was the percent of pSTAT3-positive pre-run-in tumors that became pSTAT3-negative. Secondary endpoints included pathologic complete response (pCR).

RESULTS

Overall, 23 patients were enrolled, of whom 21 completed preoperative therapy. Two patients achieved pCR (8.7%). pSTAT3 and IL-6/JAK/STAT3 signaling decreased in post-run-in biopsies of RUX-treated samples, while sustained treatment with RUX + PAC upregulated IL-6/JAK/STAT3 signaling compared to RUX alone. Both treatments decreased GZMB+ T cells implying immune suppression. RUX alone effectively inhibited JAK/STAT3 signaling but its combination with PAC led to incomplete inhibition. The immune suppressive effects of RUX alone and in combination may negate its growth inhibitory effects on cancer cells.

CONCLUSION

In summary, the use of RUX in TN-IBC was associated with a decrease in pSTAT3 levels despite lack of clinical benefit. Cancer cell-specific-targeting of JAK2/STAT3 or combinations with immunotherapy may be required for further evaluation of JAK2/STAT3 signaling as a cancer therapeutic target.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov , NCT02876302. Registered 23 August 2016.

Radiation for inflammatory breast cancer: Updates

Inflammatory breast cancer (IBC) is a diagnosis based on a constellation of clinical features of edema (peau d'orange) of a third or more of the skin of the breast with a palpable border and a rapid onset of breast erythema. Incidence of IBC has increased over time, although it still makes up only 1-4% of all breast cancer diagnoses. Despite recent encouraging data on clinical outcomes, the published local-regional control rates remain consistently lower than the rates for non-IBC. In this review, we focus on radiotherapy, provide a framework for multi-disciplinary care for IBC, describe local-regional treatment techniques for IBC; highlight new directions in the management of patients with metastatic IBC and offer an introduction to future directions regarding the optimal treatment and management of IBC.

Geometric tumor embolic budding characterizes inflammatory breast cancer

PURPOSE

Inflammatory breast cancer (IBC) is characterized by numerous tumor emboli especially within dermal lymphatics. The explanation remains a mystery.

METHODS

This study combines experimental studies with two different IBC xenografts with image algorithmic studies utilizing human tissue microarrays (TMAs) of IBC vs non-IBC cases to support a novel hypothesis to explain IBC's sina qua non signature of florid lymphovascular emboli.

RESULTS

In the human TMAs, compared to tumor features like nuclear grade (size), mitosis and Ki-67 immunoreactivity which show that IBC is only modestly more proliferative with larger nuclei than non-IBC, what really sets IBC apart is the markedly greater number of tumor emboli and distinctly smaller emboli whose numbers indicate geometric or exponential differences between IBC and non-IBC. In the experimental xenograft studies, Mary-X gives rise to tight spheroids in vitro which exhibit dynamic budding into smaller daughter spheroids whereas Karen-X exhibits only loose non-budding aggregates. Furthermore Mary-X emboli also bud dramatically into smaller daughter emboli in vivo. The mechanism that regulates this involves the generation of E-cad/NTF1, a calpain-mediated cleavage 100 kDa product of 120 kDa full length membrane E-cadherin. Inhibiting this calpain-mediated cleavage of E-cadherin by blocking either the calpain site of cleavage (SC) or the site of binding (SB) with specific decapeptides that both penetrate the cell membrane and mimic either the cleavage site or the binding site on E-cadherin, inhibits the generation of E-cad/NTF1 in a dose-dependent manner, reduces spheroid compactness and decreases budding.

CONCLUSION

Since E-cad/NFT1 retains the p120ctn binding site but loses the α-and β-catenin sites, promoting its 360° distribution around the cell's membrane, the vacilating levels of this molecule trigger budding of both the spheroids as well as the emboli. Recurrent and geometric budding of parental emboli into daughter emboli then would account for the plethora of emboli seen in IBC.

Breast Cancer Stem Cells: Signaling Pathways, Cellular Interactions, and Therapeutic Implications

Breast cancer stem cells (BCSCs) constitute a small population of cells within breast cancer and are characterized by their ability to self-renew, differentiate, and recapitulate the heterogeneity of the tumor. Clinically, BCSCs have been correlated with cancer progression, metastasis, relapse, and drug resistance. The tumorigenic roles of BCSCs have been extensively reviewed and will not be the major focus of the current review. Here, we aim to highlight how the crucial intrinsic signaling pathways regulate the fate of BCSCs, including the Wnt, Notch, Hedgehog, and NF-κB signaling pathways, as well as how different cell populations crosstalk with BCSCs within the TME, including adipocytes, endothelial cells, fibroblasts, and immune cells. Based on the molecular and cellular activities of BCSCs, we will also summarize the targeting strategies for BCSCs and related clinical trials. This review will highlight that BCSC development in breast cancer is impacted by both BCSC endogenous signaling and external factors in the TME, which provides an insight into how to establish a comprehensively therapeutic strategy to target BCSCs for breast cancer treatments.

Inflammatory Breast Cancer: The Cytokinome of Post-Mastectomy Wound Fluid Augments Proliferation, Invasion, and Stem Cell Markers

Inflammatory breast cancer (IBC) is an aggressive phenotype with a high recurrence and low survival rate. Approximately 90% of local breast cancer recurrences occur adjacent to the same quadrant as the initial cancer, implying that tumor recurrence may be caused by residual cancer cells and/or quiescent cancer stem cells (CSCs) in the tumor. We hypothesized that wound fluid (WF) collected after modified radical mastectomy (MRM) may activate cancer cells and CSCs, promoting epithelial mesenchymal transition (EMT) and invasion. Therefore, we characterized the cytokinome of WF drained from post-MRM cavities of non-IBC and IBC patients. The WF of IBC patients showed a significantly higher expression of various cytokines than in non-IBC patients. In vitro cell culture models of non-IBC and IBC cell lines were grown in media conditioned with and/without WF for 48 h. Afterwards, we assessed cell viability, the expression of CSCs and EMT-specific genes, and tumor invasion. Genes associated with CSCs properties and EMT markers were regulated in cells seeded in media conditioned by WF. IBC-WF exhibited a greater potential for inducing IBC cell invasion than non-IBC cells. The present study demonstrates the role of the post-surgical tumor cavity in IBC recurrence and metastasis.

Establishment of a new canine inflammatory mammary carcinoma cell line and analysis of its cystine-glutamate transporter subunit expression

Introduction

Inflammatory mammary carcinoma (IMC) is a rare disease with a poor prognosis and one affecting dogs. Inflammatory breast carcinoma (IBC) is a subtype of malignant breast cancer in humans with a high degree of malignancy and a similarly poor prognosis. Since the clinical symptoms and prognoses of both are similar, canine IMC has been considered as a model of human IBC. In this study, we newly established a stable IMC-derived cell line from a patient at the Yamaguchi University Animal Medical Center in Japan.

Material and Methods

The patient was a female toy poodle presenting with an inflamed mammary gland, which was diagnosed as IMC. The cell line was established from a tissue biopsy. Surface antigen marker (CD24 and CD44) expression was determined. Cystine/glutamate antiporter (xCT) expression was determined by Western blotting, flow cytometry and fluorescence immunostaining, and sulfasalazine was administered to ascertain if it suppressed xCT expression. Stem cell marker (Nanog, Sox2, Myc and Klf4) expression and aldehyde dehydrogenase (ALDH) activity were also investigated.

Results

The cultured cells showed xCT, and its suppression showed downregulation of stem cell markers and ALDH activity. Stable cell proliferation was verified.

Conclusion

A new canine IMC-derived cell line was established. In the future, we aim to study the effect of xCT on the maintenance of cancer stem cell properties in canine tumours, and propose a new therapeutic method for the treatment of canine IMC by targeting xCT.

Loss of Krüppel-like factor 9 facilitates stemness in ovarian cancer ascites-derived multicellular spheroids via Notch1/slug signaling

The ascites that develops in advanced OC, both at diagnosis and upon recurrence, is a rich source of multicellular spheroids/aggregates (MCSs/MCAs), which are the major seeds of tumor cell dissemination within the abdominal cavity. However, the molecular mechanism by which specific ascites-derived tumor cells survive and metastasize remains largely unknown. In this study, we elucidated cancer stem cell (CSC) properties of ascites-derived MCSs, concomitant with enhanced malignancy, induced EMT, and low KLF9 (Krüppel-like factor 9) expression, compared with PTCs. KLF9 was also downregulated in OC cell line-derived spheroids and the CD117⁺ CD44⁺ subpopulation in MCSs. Functional experiments demonstrated that KLF9 negatively modulated stem-like properties in OC cells. Mechanistic studies revealed that KLF9 reduced the transcriptional expression of Notch1 by directly binding to the Notch1 promoter, thereby inhibiting the function of slug in a CSL-dependent manner. Clinically, expression of KLF9 was associated with histological grade and loss of KLF9 predicts poor prognosis in OC.

Theranostics for Breast Cancer Stem Cells

Effectively targeting and treating breast cancer stem cells (BCSCs), which have been linked to tumor development and metastasis, and recurrence still remains a challenging issue in preclinic and clinic. Screening and identifying characteristic BCSC biomarkers is important for distinguishing BCSCs from differentiated tumor cells within the tumor mass. Molecular imaging and nanotechnology are evolving as new fields that have a potentially high research and clinical impact. Developing the biocompatible contrast agents conjugated with high-affinity biomarker to selectively target BCSCs and is one of the key prerequisites for image-guided diagnosis and monitoring therapy of BCSCs. Very recently, we documented the extra domain-B fibronectin (EDB-FN), which is considered as a new putative biomarker for BCSCs (NDY-1 cell) derived from human breast carcinosarcoma. We here review BCSC-targeted theranostics in vitro and in vivo by delivering siRNA or drug using the nanoparticles conjugated with a small peptide specific to EDB-FN.

Phase I study of JAK1/2 inhibitor ruxolitinib with weekly paclitaxel for the treatment of HER2-negative metastatic breast cancer

PURPOSE

Preclinical studies support the JAK2-STAT3 signaling pathway as a key driver in CD44+ CD24- "stem-cell-like" breast cancer cells. Ruxolitinib is an orally bioavailable JAK1/2 inhibitor. We aimed to identify the recommended phase 2 dose (RP2D) of ruxolitinib in combination with paclitaxel in patients with HER2-negative metastatic breast cancer (MBC).

METHODS

Eligible patients had HER2-negative MBC and had received ≤ 3 chemotherapy regimens for advanced disease. Patients received oral ruxolitinib (10-25 mg bid) in a 3 + 3 dose escalation design in combination with weekly paclitaxel 80 mg/m² in a 3-week cycle. The primary objective was to determine the maximum tolerated dose (MTD) and the RP2D.

RESULTS

Nineteen patients received protocol therapy (mean age 52 years). Eight (42%) had triple-negative breast cancer and 11 (58%) had hormone receptor-positive disease; 12 (63%) had visceral disease. Ten (53%) patients had not received prior treatment for advanced disease. Patients received a median number of 5 cycles of combination therapy (range 1-12) and five patients continued single-agent ruxolitinib. The MTD of ruxolitinib was 25 mg bid when combined with paclitaxel, and the RP2D for the combination was 15 mg bid. Thirteen (68%) patients required dose reductions or holds. Most frequent toxicities reported of any grade were neutropenia (50%) and anemia (33%). There were no grade 4/5 toxicities attributed to study drug. Four (21%) patients had PR, 12 (63%) had SD and three (16%) had PD as their best response.

CONCLUSION

The combination of ruxolitinib and weekly paclitaxel was well tolerated with evidence of clinical activity. Further analysis of this combination is ongoing (NCT02041429).

TRIAL REGISTRATION

NCT02041429. Date of registration: January 22, 2014.

Inflammatory Breast Cancer: a Separate Entity

PURPOSE OF REVIEW

Inflammatory breast cancer (IBC) is an uncommon but highly aggressive subtype of breast cancer that contributes significantly to breast cancer-related mortality. In this review, we provide an overview of the clinical and molecular characteristics of IBC, and highlight some areas of need for ongoing research.

RECENT FINDINGS

The disease is characterized by florid tumor emboli that obstruct dermal lymphatics, leading to swelling and inflammation of the affected breast. Recent studies have focused on tumor cell intrinsic features, such as signaling through pathways involved in growth and stem-like behavior, as well as extrinsic features, such as the immune system, that can be leveraged to develop new potential therapies. Key efforts have led to an increase in awareness of the disease as well as new insights into IBC pathogenesis. However, there is a strong need for new therapies designed specifically for IBC, and many unanswered questions remain.

Role of the RAB7 Protein in Tumor Progression and Cisplatin Chemoresistance

RAB7 is a small guanosine triphosphatase (GTPase) extensively studied as regulator of vesicular trafficking. Indeed, its role is fundamental in several steps of the late endocytic pathway, including endosome maturation, transport from early endosomes to late endosomes and lysosomes, clustering and fusion of late endosomes and lysosomes in the perinuclear region and lysosomal biogenesis. Besides endocytosis, RAB7 is important for a number of other cellular processes among which, autophagy, apoptosis, signaling, and cell migration. Given the importance of RAB7 in these cellular processes, the interest to study the role of RAB7 in cancer progression is widely grown. Here, we describe the current understanding of oncogenic and oncosuppressor functions of RAB7 analyzing cellular context and other environmental factors in which it elicits pro and/or antitumorigenic effects. We also discuss the role of RAB7 in cisplatin resistance associated with its ability to regulate the late endosomal pathway, lysosomal biogenesis and extracellular vesicle secretion. Finally, we examined the potential cancer therapeutic strategies targeting the different molecular events in which RAB7 is involved.

GLI1 activation by non-classical pathway integrin αvβ3/ERK1/2 maintains stem cell-like phenotype of multicellular aggregates in gastric cancer peritoneal metastasis

Peritoneal metastasis is one of the most important causes of postoperative death in patients with gastric cancer, and the exact mechanism remains unclear. The proliferation of multicellular aggregates of exfoliated malignant gastric cells in the abdominal cavity is the focus of current research. However, the mechanism how gastric cancer multicellular aggregates survive remains unclear. In this study, we demonstrated that multicellular aggregates of exfoliated gastric cancer cells in the abdominal cavity expressed a stem cell-Like phenotype. We found that Integrin α_vβ₃ not only mediated adhesion of gastric cancer multicellular aggregates to form independent functional units, but also maintained their stem cell-like phenotype by the non-classical pathway Integrin α_vβ₃/ERK1/2/GLI1. In addition, ERK1/2 directly regulates the transcriptional activity of GLI1. GLI1 is a key effector of the Integrin α_vβ₃ pathway in regulating stem cell-like phenotype in multicellular aggregates. Our data indicates that although there is a crosstalk between the non-classical Integrin α_vβ₃ pathway and the classical Hedgehog pathway, the activation of GLI1 is almost independent of the Hedgehog pathway in multicellular aggregates of gastric cancer cells. Our study provides a basis for blocking GLI1 activity in the prevention and treatment of peritoneal metastases of gastric cancer.

Inflammatory breast cancer: Activation of the aryl hydrocarbon receptor and its target CYP1B1 correlates closely with Wnt5a/b-β-catenin signalling, the stem cell phenotype and disease progression

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AHR is over-expressed and hyperactivated in carcinoma tissues of IBC patients.

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AHR knockdown inhibits expression of CYP1B1 and Wnt5a in IBC cells.

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AHR and CYP1B1 expression correlates with Wnt5 a/b and b-catenin expression levels.

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AHR and CYP1B1 expression correlates with percentage of CD44⁽⁺⁾/CD24^(−/low) subset in IBC.

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AHR and its surrogate molecules correlate with IBC poor prognosis.

The aim of the present study was to evaluate the expression levels of the aryl hydrocarbon receptor (AHR) and its target gene CYP1B1 and to correlate their expression with Wnt5a/b-β-catenin, the CD44⁺/CD24^(−/low) cancer stem cell (CSC) subset and factors associated with poor prognosis in inflammatory breast cancer (IBC) and non-IBC patients. The methods of analysis used were quantitative real-time PCR, western blotting, immunohistochemistry and flow cytometry. Compared to non-IBC tissues, IBC tissues exhibited the overexpression of AHR and its target gene/protein CYP1B1. AHR and CYP1B1 mRNA levels were associated with the poor clinical prognosis markers tumour grade, lymphovascular invasion, cell proliferation and lymph node metastasis. Furthermore, AHR expression correlated with the expression of Wnt5a/b and β-catenin signalling molecules, and Wnt5a mRNA expression was downregulated in the SUM149 human IBC cell line and the MDA-MB-231 non-IBC cell line upon inhibition of AHR. AHR gene knockout (CRISPR-Cas9) inhibits CYP1B1 and Wnt5a expression in the IBC cell line. The CD44⁺/CD24^(−/low) subset was significantly correlated with the expression of AHR, CYP1B1, Wnt5a/b and β-catenin in IBC tissues. The overexpression of AHR and its target CYP1B1 correlated with the expression of Wnt5a/b and β-catenin, CSCs, and poor clinical prognostic factors of IBC. Thus, targeting AHR and/or its downstream target molecules CYP1B1 and Wnt5a/b may represent a therapeutic approach for IBC.

Survival nomograms for stage III colorectal cancer

The postoperative survival of patients with stage III colorectal cancer (CRC) various obviously. We sought to develop novel nomograms for predicting the survival of these patients after radical surgery and postoperative chemotherapy.A total of 620 consecutive patients with stage III CRC who underwent curative resection and postoperative chemotherapy between January 2009 and December 2015 were retrospectively collected and randomly allocated to the training (n = 372) or validation cohort (n = 248). Clinicopathological factors were collected and analyzed. On the basis of data from 372 patients in the training set, predictive factors for overall survival (OS) and disease-free survival (DFS) were identified using multivariate Cox regression and used to construct nomograms. The predictive performance of the nomograms was assessed by concordance index (C-index) and calibration plots. An external cohort of 248 patients was used to validate the nomograms. Furthermore, nomogram performance was compared with the performance of T and N stage stratification.Tumor differentiation grade, lymph node metastasis ratio, intravascular emboli (IVE), preoperative serum carcinoembryonic antigen (CEA) level, albumin to globulin ratio (AGR), T stage and N stage were significant prognostic factors for OS on multivariate analysis; whereas, Tumor differentiation grade, lymph node metastasis ratio, IVE, AGR and N stage were significant for DFS. Nomograms to predict 3- and 5-year OS and DFS were established that performed well (C-indexes of 0.734 [95% CI, 0.691-0.779] for OS and 0.699 [95% CI, 0.657-0.740] for DFS prediction), and nomogram accuracy was confirmed in the validation cohort. Furthermore, model comparison proved that the nomograms were superior to risk stratification by T and N stage for stage III CRC.We propose 2 practical nomograms for stage III CRC patients that provide more accurate prognostic predictions and should be helpful for guiding individualized treatment and postoperative surveillance.

Hybrid epithelial/mesenchymal phenotypes promote metastasis and therapy resistance across carcinomas

Cancer metastasis and therapy resistance are the major unsolved clinical challenges, and account for nearly all cancer-related deaths. Both metastasis and therapy resistance are fueled by epithelial plasticity, the reversible phenotypic transitions between epithelial and mesenchymal phenotypes, including epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). EMT and MET have been largely considered as binary processes, where cells detach from the primary tumor as individual units with many, if not all, traits of a mesenchymal cell (EMT) and then convert back to being epithelial (MET). However, recent studies have demonstrated that cells can metastasize in ways alternative to traditional EMT paradigm; for example, they can detach as clusters, and/or occupy one or more stable hybrid epithelial/mesenchymal (E/M) phenotypes that can be the end point of a transition. Such hybrid E/M cells can integrate various epithelial and mesenchymal traits and markers, facilitating collective cell migration. Furthermore, these hybrid E/M cells may possess higher tumor-initiation and metastatic potential as compared to cells on either end of the EMT spectrum. Here, we review in silico, in vitro, in vivo and clinical evidence for the existence of one or more hybrid E/M phenotype(s) in multiple carcinomas, and discuss their implications in tumor-initiation, tumor relapse, therapy resistance, and metastasis. Together, these studies drive the emerging notion that cells in a hybrid E/M phenotype may occupy 'metastatic sweet spot' in multiple subtypes of carcinomas, and pathways linked to this (these) hybrid E/M state(s) may be relevant as prognostic biomarkers as well as a promising therapeutic targets.

Implications of nestin in breast cancer pathogenesis (Review)

The aim of the present review was to summarize the current knowledge of the involvement of nestin in breast cancer (BC) pathogenesis. Nestin is a member of the class VI family of intermediate filament proteins, originally identified as a marker of neural stem cells and subsequently demonstrated to be expressed in BC and other cancer types. In normal breast tissue, nestin is expressed in the basal/myoepithelial cells of the mammary gland. In BC, nestin identifies basal-like tumours and predicts aggressive behaviour and poor prognosis. Nestin expression has also been detected in BC stem cells and newly-formed tumour vessels, being a factor in promoting invasion and metastasis. The present review provides an up-to-date overview of the involvement of nestin in processes facilitating BC pathogenesis and progression.

Effects of indole-3-carbinol on steroid hormone profile and tumor progression in a mice model of canine inflammatory mammarycancer

Background

Indole-3-carbinol, derived from Cruciferous vegetables is an estrogen receptor antagonist considered a preventive agent that is naturally present in diet. There are no previous studies on its effects in human inflammatory breast cancer or canine inflammatory mammary cancer that is the most aggressive type of breast cancer.

Methods

The aim of this study was to analyze the effect of indole-3-carbinol on a SCID mice xenograft model of canine inflammatory mammary cancer, using equivalent human oral dose as a preventive therapy in humans for 3 weeks.

Results

Indole-3-carbinol treatment decreased tumor proliferation and increased apoptosis, although tumor embolization and liver metastasis were observed in some animals. There was a characteristic subpopulation of lipid-rich cells and increased contents of select steroid hormones in tumor homogenates and serum.

Conclusions

Our data reveal for the first time that the ingestion of indole-3-carbinol, as administered, diminishes proliferation and increases apoptosis of tumor cells in an experimental model of inflammatory breast cancer, although this effect could not be enough to avoid the appearance of tumor embolization and metastasis. Future clinical trials will be needed to clarify the usefulness of indole-3-carbinol in this cancer and to understand the molecular mechanisms involved.

Intravascular emboli is an independent risk factor for the prognosis of stage III colorectal cancer patients after radical surgery

Lymphovascular emboli is a prognostic factor in stage II CRC, but the significance of intravascular emboli (IVE) in stage III is unclear. Data from consecutive stage III CRC patients receiving radical surgery between January 2009 and November 2014 were retrospectively collected. The expression of CD133 was tested by immumohistochemical (IHC) staining. The potential prognosis risk factors were tested using univariate and multivariate survival analyses. IVE was significantly associated with CD133 expression (P < 0.001), gross tumor morphology (P = 0.001), histologic type (p < 0.001), lymph node status (pN) (p < 0.001), sub-class of stage III (p = 0.001), and serum CA199 level (p = 0.022). IVE, CD133 expression and lymph node status (pN) were independent risk factors for overall survival (OS) (p < 0.001, p = 0.003, and p = 0.008, respectively) and disease-free survival (DFS) (p < 0.001, p = 0.004, and p = 0.007, respectively) in stage III CRC. IVE might be an independent risk factor for the prognosis of stage III CRC patients after radical surgery. IVE might express a cancer stem cell (CSC) phenotype.

Effect of statins on breast cancer recurrence and mortality: a review

Statins, or 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, are medications that have been used for decades to lower cholesterol and to prevent or treat cardiovascular diseases. Since their approval by the US Food and Drug Administration in the 1980s, other potential uses for statins have been speculated on and explored. Basic science and clinical research suggest that statins are also effective in the management of breast cancer. Specifically, in various breast cancer cell lines, statins increase apoptosis and radiosensitivity, inhibit proliferation and invasion, and decrease the metastatic dissemination of tumors. Clinical trials in breast cancer patients support these laboratory findings by demonstrating improved local control and a mortality benefit for statin users. A role for statins in the management of aggressive breast cancers with poor outcomes – namely, inflammatory breast cancer and triple-negative breast cancer – is particularly implicated. However, data exist showing that statins may actually promote invasive breast disease after long-term use and thus should be prescribed cautiously. Furthermore, a general consensus on the type of statin that should be administered, for how long, and when in relation to time of diagnosis is lacking. Given their low toxicity profile, affordability, and ease of use, consideration of statins as a therapy for breast cancer patients is imminent. In this review, we summarize current evidence regarding statins and clinical breast cancer outcomes, as well as discuss potential future studies that could shed light on this increasingly relevant topic.

Challenging a Misnomer? The Role of Inflammatory Pathways in Inflammatory Breast Cancer

Inflammatory breast cancer is a rare, yet highly aggressive form of breast cancer, which accounts for less than 5% of all locally advanced presentations. The clinical presentation of inflammatory breast cancer often differs significantly from that of noninflammatory breast cancer; however, immunohistochemistry reveals few, if any, distinguishing features. The more aggressive triple-negative and HER2-positive breast cancer subtypes are overrepresented in inflammatory breast cancer compared with noninflammatory breast cancer, with a poorer prognosis in response to conventional therapies. Despite its name, there remains some controversy regarding the role of inflammation in inflammatory breast cancer. This review summarises the current molecular evidence suggesting that inflammatory signaling pathways are upregulated in this disease, including NF-κB activation and excessive IL-6 production among others, which may provide an avenue for novel therapeutics. The role of the tumor microenvironment, through tumor-associated macrophages, infiltrating lymphocytes, and cancer stem cells is also discussed, suggesting that these tumor extrinsic factors may help account for the differences in behavior between inflammatory breast cancer and noninflammatory breast cancer. While there are various novel treatment strategies already underway in clinical trials, the need for further development of preclinical models of this rare but aggressive disease is paramount.

Syndecan-1 is a novel molecular marker for triple negative inflammatory breast cancer and modulates the cancer stem cell phenotype via the IL-6/STAT3, Notch and EGFR signaling pathways

Background

Inflammatory breast cancer (IBC), a particularly aggressive form of breast cancer, is characterized by cancer stem cell (CSC) phenotype. Due to a lack of targeted therapies, the identification of molecular markers of IBC is of major importance. The heparan sulfate proteoglycan Syndecan-1 acts as a coreceptor for growth factors and chemokines, modulating inflammation, tumor progression, and cancer stemness, thus it may emerge as a molecular marker for IBC.

Methods

We characterized expression of Syndecan-1 and the CSC marker CD44, Notch-1 & -3 and EGFR in carcinoma tissues of triple negative IBC (n = 13) and non-IBC (n = 17) patients using qPCR and immunohistochemistry. Impact of siRNA-mediated Syndecan-1 knockdown on the CSC phenotype of the human triple negative IBC cell line SUM-149 and HER-2-overexpressing non-IBC SKBR3 cells employing qPCR, flow cytometry, Western blotting, secretome profiling and Notch pharmacological inhibition experiments. Data were statistically analyzed using Student’s t-test/Mann-Whitney U-test or one-way ANOVA followed by Tukey’s multiple comparison tests.

Results

Our data indicate upregulation and a significant positive correlation of Syndecan-1 with CD44 protein, and Notch-1 & -3 and EGFR mRNA in IBC vs non-IBC. ALDH1 activity and the CD44⁽⁺⁾CD24^(-/low) subset as readout of a CSC phenotype were reduced upon Syndecan-1 knockdown. Functionally, Syndecan-1 silencing significantly reduced 3D spheroid and colony formation. Intriguingly, qPCR results indicate downregulation of the IL-6, IL-8, CCL20, gp130 and EGFR mRNA upon Syndecan-1 suppression in both cell lines. Moreover, Syndecan-1 silencing significantly downregulated Notch-1, -3, -4 and Hey-1 in SUM-149 cells, and downregulated only Notch-3 and Gli-1 mRNA in SKBR3 cells. Secretome profiling unveiled reduced IL-6, IL-8, GRO-alpha and GRO a/b/g cytokines in conditioned media of Syndecan-1 knockdown SUM-149 cells compared to controls. The constitutively activated STAT3 and NFκB, and expression of gp130, Notch-1 & -2, and EGFR proteins were suppressed upon Syndecan-1 ablation. Mechanistically, gamma-secretase inhibition experiments suggested that Syndecan-1 may regulate the expression of IL-6, IL-8, gp130, Hey-1, EGFR and p-Akt via Notch signaling.

Conclusions

Syndecan-1 acts as a novel tissue biomarker and a modulator of CSC phenotype of triple negative IBC via the IL-6/STAT3, Notch and EGFR signaling pathways, thus emerging as a promising therapeutic target for IBC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0621-z) contains supplementary material, which is available to authorized users.

Molecular characterization of CD44+/CD24-/Ck+/CD45- cells in benign and malignant breast lesions

Breast cancer epithelial cells with the CD44⁺/CD24^-/low phenotype possess tumor-initiating cells and epithelial-mesenchymal transition (EMT) capacity. Massive parallel sequencing can be an interesting approach to deepen the molecular characterization of these cells. We characterized CD44⁺/CD24^-/cytokeratin(Ck)⁺/CD45^- cells isolated through flow cytometry from 43 biopsy and 6 mastectomy samples harboring different benign and malignant breast lesions. The Ion Torrent Ampliseq Cancer Hotspot panel v2 (CHPv2) was used for the identification of somatic mutations in the DNA extracted from isolated CD44⁺/CD24^-/Ck⁺/CD45^- cells. E-Cadherin and vimentin immunohistochemistry was performed on sections from the corresponding formalin-fixed, paraffin-embedded (FFPE) blocks. The percentage of CD44⁺/CD24^-/Ck⁺/CD45^- cells increased significantly from non-malignant to malignant lesions and in association with a significant increase in the expression of vimentin. Non-malignant lesions harbored only a single-nucleotide polymorphism (SNP). Mutations in the tumor suppressor p53 (TP53), NOTCH homolog 1 (NOTCH1), phosphatase and tensin homolog (PTEN), and v-akt murine thymoma viral oncogene homolog 1 (AKT1) genes were found in isolated CD44⁺/CD24^-/Ck⁺/CD45^- cells from ductal carcinomas in situ (DCIS). Additional mutations in the colony-stimulating factor 1 receptor (CSF1R), ret proto-oncogene (RET), and TP53 genes were also identified in invasive ductal carcinomas (IDCs). The use of massive parallel sequencing technology for this type of application revealed to be extremely effective even when using small amounts of DNA extracted from a low number of cells. Additional studies are now required using larger cohorts to design an appropriate mutational profile for this phenotype.

Donor-derived stem-cells and epithelial mesenchymal transition in squamous cell carcinoma in transplant recipients

Background

Skin squamous-cell-carcinoma (SCC), is the main complication in long-term kidney-transplant recipients, and it can include donor-derived cells. Preclinical models demonstrated the involvement of epithelial mesenchymal transition (EMT) in the progression of skin SCC, and the role of Snail, an EMT transcription factor, in cancer stem-cell survival and expansion.

Here, we studied stem-cells and EMT expression in SCCs and concomitant actinic keratoses (AK) in kidney-transplant recipients.

Methods

In SCC and AK in 3 female recipients of male kidney-transplants, donor-derived Y chromosome in epidermal stem cells was assessed using combined XY-FISH/CD133 immunostaining, and digital-droplet-PCR on laser-microdissected CD133 expressing epidermal cells.

For EMT study, double immunostainings of CD133 with vimentin or snail and slug, electron microscopy and immunostainings of keratinocytes junctions were performed. Digital droplet PCR was used to check CDH1 (E-cadherin) expression level in laser-microdissected cells co-expressing CD133 and vimentin or snail and slug.

The numbers of Y-chromosome were assessed using digital droplet PCR in laser-microdissected cells co-expressing CD133 and vimentin, or snail and slug, and in CD133 positive cells not expressing any EMT maker.

Results

We identified donor-derived stem-cells in basal layers and invasive areas in all skin SCCs and in concomitant AKs, but not in surrounding normal skin.

The donor-derived stem-cells expressed the EMT markers, vimentin, snail and slug in SCCs but not in AKs. The expression of the EMT transcription factor, SNAI1, was higher in stem-cells when they expressed vimentin. They were located in invasive areas of SCCs. In these areas, the expressions of claudin-1 and desmoglein 1 were reduced or absent, and within the basal layer there were features of basal membrane disappearance.

Donor-derived stem cells were in larger numbers in stem cells co-expressing vimentin or snail and slug than in stem cells not expressing any EMT marker.

Conclusion

We identified here donor-derived stem cells within skin SCC in kidney-transplant recipients. They were located in invasive areas of SCC and had EMT characteristics.

HDAC6 activity is a non-oncogene addiction hub for inflammatory breast cancers

INTRODUCTION

Inflammatory breast cancer (IBC) is the most lethal form of breast cancers with a 5-year survival rate of only 40 %. Despite its lethality, IBC remains poorly understood which has greatly limited its therapeutic management. We thus decided to utilize an integrative functional genomic strategy to identify the Achilles' heel of IBC cells.

METHODS

We have pioneered the development of genetic tools as well as experimental and analytical strategies to perform RNAi-based loss-of-function studies at a genome-wide level. Importantly, we and others have demonstrated that these functional screens are able to identify essential functions linked to certain cancer phenotypes. Thus, we decided to use this approach to identify IBC specific sensitivities.

RESULTS

We identified and validated HDAC6 as a functionally necessary gene to maintain IBC cell viability, while being non-essential for other breast cancer subtypes. Importantly, small molecule inhibitors for HDAC6 already exist and are in clinical trials for other tumor types. We thus demonstrated that Ricolinostat (ACY1215), a leading HDAC6 inhibitor, efficiently controls IBC cell proliferation both in vitro and in vivo. Critically, functional HDAC6 dependency is not associated with genomic alterations at its locus and thus represents a non-oncogene addiction. Despite HDAC6 not being overexpressed, we found that its activity is significantly higher in IBC compared to non-IBC cells, suggesting a possible rationale supporting the observed dependency.

CONCLUSION

Our finding that IBC cells are sensitive to HDAC6 inhibition provides a foundation to rapidly develop novel, efficient, and well-tolerated targeted therapy strategies for IBC patients.

Spherical cancer models in tumor biology

Three-dimensional (3D) in vitro models have been used in cancer research as an intermediate model between in vitro cancer cell line cultures and in vivo tumor. Spherical cancer models represent major 3D in vitro models that have been described over the past 4 decades. These models have gained popularity in cancer stem cell research using tumorospheres. Thus, it is crucial to define and clarify the different spherical cancer models thus far described. Here, we focus on in vitro multicellular spheres used in cancer research. All these spherelike structures are characterized by their well-rounded shape, the presence of cancer cells, and their capacity to be maintained as free-floating cultures. We propose a rational classification of the four most commonly used spherical cancer models in cancer research based on culture methods for obtaining them and on subsequent differences in sphere biology: the multicellular tumor spheroid model, first described in the early 70s and obtained by culture of cancer cell lines under nonadherent conditions; tumorospheres, a model of cancer stem cell expansion established in a serum-free medium supplemented with growth factors; tissue-derived tumor spheres and organotypic multicellular spheroids, obtained by tumor tissue mechanical dissociation and cutting. In addition, we describe their applications to and interest in cancer research; in particular, we describe their contribution to chemoresistance, radioresistance, tumorigenicity, and invasion and migration studies. Although these models share a common 3D conformation, each displays its own intrinsic properties. Therefore, the most relevant spherical cancer model must be carefully selected, as a function of the study aim and cancer type.

The clinicopathological and prognostic significance of CD24, CD44, CD133, ALDH1 expressions in invasive ductal carcinoma of the breast: CD44/CD24 expression in breast cancer

BACKGROUND

Recently, there are several studies about cancer stem cells (CSC), indicating that they are the cells that initiate the tumor, provide progression, metastasis and responsible for the aggressive tumor behavior.

MATERIALS AND METHODS

The purpose of this study is to investigate the expressions of CD24, CD44, their different combinations, ALDH1 and CD133 in invasive ductal carcinoma. Their relationships with clinicopathologic parameters, such as tumor grade, lymphovascular invasion, tumor size, axillary lymph node involvement, stage, hormone receptors, HER2 expression, basal like tumors, triple negative status and prognosis were also investigated. Tissue microarray method was used to investigate ımmunohistochemical CD24, CD44, ALDH1 and CD133 expressions in 105 invasive ductal carcinoma cases.

RESULTS

CD133 expression was significantly associated with tumor size (p=0.023) and stage (p=0.009). CD133 expression was decreased in tumors with larger tumor size, higher stage and lymphovascular invasion. CD133 expression was positively correlated with CD44 (r=0.212, p=0.032) and CD44(+)/CD24(+) (r=0.202, p=0.040) expressions. CD44, CD24 and ALDH1 expressions showed no significant relationship and correlation with clinicopathologic features. There was a significant relationship (p=0.048) between CD44(+)/CD24(-/low) phenotype and basal like tumors. EGFR expression was positively correlated with CD44(+)/CD24(-/low) phenotype (r=0.211, p=0.036).

CONCLUSIONS

Basal like tumors are enriched for CSCs with CD44(+)/CD24(-/low) phenotype. CD133 can detect a different population of CSC in breast carcinoma.

Mesenchymal stem cells mediate the clinical phenotype of inflammatory breast cancer in a preclinical model

INTRODUCTION

Inflammatory breast cancer (IBC) is an aggressive type of breast cancer, characterized by very rapid progression, enlargement of the breast, skin edema causing an orange peel appearance (peau d'orange), erythema, thickening, and dermal lymphatic invasion. It is characterized by E-cadherin overexpression in the primary and metastatic disease, but to date no robust molecular features that specifically identify IBC have been reported. Further, models that recapitulate all of these clinical findings are limited and as a result no studies have demonstrated modulation of these clinical features as opposed to simply tumor cell growth.

METHODS

Hypothesizing the clinical presentation of IBC may be mediated in part by the microenvironment, we examined the effect of co-injection of IBC xenografts with mesenchymal stem/stromal cells (MSCs).

RESULTS

MSCs co-injection significantly increased the clinical features of skin invasion and metastasis in the SUM149 xenograft model. Primary tumors co-injected with MSCs expressed higher phospho-epidermal growth factor receptor (p-EGFR) and promoted metastasis development after tumor resection, effects that were abrogated by treatment with the epidermal growth factor receptor (EGFR) inhibitor, erlotinib. E-cadherin expression was maintained in primary tumor xenografts with MSCs co-injection compared to control and erlotinib treatment dramatically decreased this expression in control and MSCs co-injected tumors. Tumor samples from patients demonstrate correlation between stromal and tumor p-EGFR staining only in IBC tumors.

CONCLUSIONS

Our findings demonstrate that the IBC clinical phenotype is promoted by signaling from the microenvironment perhaps in addition to tumor cell drivers.

Circulating tumor cells in newly diagnosed inflammatory breast cancer

Introduction

Circulating tumor cells (CTCs) are an independent prognostic factor for progression-free survival (PFS) and overall survival (OS) in patients with metastatic breast cancer. Inflammatory breast cancer (IBC) is one of the most aggressive forms of breast cancer. The prognostic value of a CTC count in newly diagnosed IBC has not been established. The aim of this study was to assess the prognostic value of a baseline CTC count in patients with newly diagnosed IBC.

Methods

This retrospective study included 147 patients with newly diagnosed IBC (77 with locally advanced and 70 with metastatic IBC) treated with neoadjuvant therapy or first-line chemotherapy during the period from January 2004 through December 2012 at The University of Texas MD Anderson Cancer Center. CTCs were detected and enumerated by using the CellSearch system before patients were started with chemotherapy.

Results

The proportion of patients with ≥1 CTC was lower among patients with stage III than among patients with metastatic IBC (54.5% versus 84.3%; P = 0.0002); the proportion of patients with ≥5 CTCs was also lower for stage III than for metastatic IBC (19.5% versus 47.1%; P = 0.0004). Patients with fewer than five CTCs had significantly better progression-free survival (PFS) (hazard ratio (HR) = 0.60; P = 0.02) and overall survival (HR = 0.59; P = 0.03) than patients with five or more CTCs. Among patients with stage III IBC, there was a nonsignificant difference in PFS (HR = 0.66; 95% confidence interval (CI), 0.31 to 1.39; P = 0.29) and OS (HR = 0.54; 95% CI, 0.24 to 1.26; P = 0.48) in patients with no CTCs compared with patients with one or more CTCs. In multivariate analysis, CTC was prognostic for PFS and OS independent of clinical stage.

Conclusions

CTCs can be detected in a large proportion of patients with newly diagnosed IBC and are a strong predictor of worse prognosis in patients with newly diagnosed IBC.

Blockade of extracellular NM23 or its endothelial target slows breast cancer growth and metastasis

BACKGROUND

Nucleoside Diphosphate Kinase (NDPK), described as NM23 a metastasis suppressor, is found in the culture medium of cancer cells lines suggesting that the kinase may have an extracellular role. We propose that extracellular NM23 released from breast cancers in vivo stimulates tumor cell migration, proliferation and endothelial cell angiogenesis in support of metastasis development.

METHODS

NM23 in the bloodstream of immunocompromised mice carrying human triple-negative breast cancers or in breast cancer patients was measured by ELISA. Primary and metastatic tumor development, the impact of blockade of NM23 and/or its stimulation of nucleotide receptors were measured using in vivo imaging. NM23 expression data in the Curtis breast dataset was examined to test our hypothesis that NM23 may play a mechanistic role in breast cancer development.

RESULTS

SCID mice carrying metastatic MDA-MB-231Luc+ triple-negative human breast tumor cells elaborate NM23 into the circulation correlated with primary tumor growth. Treatment of mice with the NM23 inhibitor ellagic acid (EA) or the purinergic receptor antagonist MRS2179 slowed primary tumor growth. At 16 weeks following implantation, lung metastases were reduced in mice treated with EA, MRS2179 or the combination. Expression of NM23 in the Curtis breast dataset confirmed a likely role for NM23 in tumor metastasis.

CONCLUSIONS

Extracellular NM23 may constitute both a biomarker and a therapeutic target in the management of breast cancer.

Inflammatory breast cancer: high incidence of detection of mixed human cytomegalovirus genotypes associated with disease pathogenesis

Inflammatory breast cancer (IBC) is a highly metastatic, aggressive, and fatal form of breast cancer. Patients presenting with IBC are characterized by a high number of axillary lymph node metastases. Recently, we found that IBC carcinoma tissues contain significantly higher levels of human cytomegalovirus (HCMV) DNA compared to other breast cancer tissues that may regulate cell signaling pathways. In fact, HCMV pathogenesis and clinical outcome can be statistically associated with multiple HCMV genotypes within IBC. Thus, in the present study, we established the incidence and types of HCMV genotypes present in carcinoma tissues of infected non-IBC versus IBC patients. We also assessed the correlation between detection of mixed genotypes of HCMV and disease progression. Genotyping of HCMV in carcinoma tissues revealed that glycoprotein B (gB)-1 and glycoprotein N (gN)-1 were the most prevalent HCMV genotypes in both non-IBC and IBC patients with no significant difference between patients groups. IBC carcinoma tissues, however, showed statistically significant higher incidence of detection of the gN-3b genotype compared to non-IBC patients. The incidence of detection of mixed genotypes of gB showed that gB-1 + gB-3 was statistically significantly higher in IBC than non-IBC patients. Similarly, the incidence of detection of mixed genotypes of gN showed that gN-1 + gN-3b and gN-3 + gN-4b/c were statistically significant higher in the carcinoma tissues of IBC than non-IBC. Mixed presence of different HCMV genotypes was found to be significantly correlated with the number of metastatic lymph nodes in non-IBC but not in IBC patients. In IBC, detection of mixed HCMV different genotypes significantly correlates with lymphovascular invasion and formation of dermal lymphatic emboli, which was not found in non-IBC patients.

Aldehyde dehydrogenase 1 expression in inflammatory breast cancer as measured by immunohistochemical staining

BACKGROUND

Inflammatory breast cancer (IBC) is a rare but aggressive type of breast carcinoma. Despite multimodality approaches, the clinical outcome of patients with IBC remains poor. Tumors arising from cancer stem cells (CSCs) are associated with drug resistance, tumor recurrence, and poor prognosis. This study aimed to evaluate expression of aldehyde dehydrogenase 1 (ALDH1), a putative stem cell marker, in IBC tumors.

MATERIALS AND METHODS

Tissue microarrays of 74 surgically resected IBC tumors were immunohistochemically stained for ALDH1. The results were correlated with clinicopathologic parameters and survival data and were compared with findings published in the literature.

RESULTS

The median follow-up time of the cohort was 42.1 months, and the 5-year overall survival (OS) rate was 46%. Twenty-four tumors (32%) were positive for ALDH1 staining. However, ALDH1 expression was not significantly associated with clinicopathologic variables, including lymph node status, tumor grade, and the status of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Log-rank testing found that ALDH1 expression was not significantly associated with the OS rate, although there was a trend toward an association with lower OS rate (P = .07). The findings were consistent with some of the published data, but substantial inconsistency among reports was noted.

CONCLUSION

In this IBC cohort, no significant correlation between ALDH1 expression and prognosis or other clinicopathologic variables was found. Although sample size and selection criteria may be contributory factors, inconsistent results reported in the literature raise concern regarding the reliability of immunohistochemically identified ALDH1 as a sole marker of breast CSCs. Further study is required to elucidate the significance of CSCs in IBC biology.

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.

Cleavage of E-cadherin and β-catenin by calpain affects Wnt signaling and spheroid formation in suspension cultures of human pluripotent stem cells

The envisioned clinical and industrial use of human pluripotent stem cells and their derivatives has given major momentum to the establishment of suspension culture protocols that enable the mass production of cells. Understanding molecular changes accompanying the transfer from adherent to suspension culture is of utmost importance because this information can have a direct effect on the development of optimized culture conditions. In this study we assessed the gene expression of human embryonic stem cells and induced pluripotent stem cells grown in surface-adherent culture (two-dimensional) versus free-floating suspension culture spheroids (three-dimensional). We combined a quantitative proteomic approach based on stable isotope labeling by amino acids in cell culture with deep-sequencing-based transcriptomics. Cells in three-dimensional culture showed reduced expression of proteins forming structural components of cell-cell and cell-extracellular matrix junctions. However, fully unexpected, we found up-regulation of secreted inhibitors of the canonical Wnt signaling pathway and, concomitantly, a reduction in the level of active β-catenin and in the expression of Wnt target genes. In Western blot analyses the cysteine protease calpain was shown to cleave E-cadherin and β-catenin under three-dimensional culture conditions. Our data allowed the development of a model in which calpain cleavage of E-cadherin induces the disintegration of focal cell contacts and generates a 100-kDa E-cadherin fragment required for the formation of three-dimensional cell-cell contacts in spheroids. The parallel release of β-catenin and its potential activation by calpain cleavage are counterbalanced by the overexpression of soluble Wnt pathway inhibitors. According to this model, calpain has a key function in the interplay between E-cadherin and β-catenin-mediated intercellular adhesion and the canonical Wnt signaling pathway. Supporting this model, we show that pharmacological modulation of calpain activity prevents spheroid formation and causes disassembly of preexisting spheroids into single cells, thereby providing novel strategies for improving suspension culture conditions for human pluripotent stem cells in the future.

The role of inflammation in inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer. Despite extensive study, whether inflammation contributes to the tumorigenicity or aggressiveness of IBC remains largely unknown. In this chapter, we will review the potential role played by inflammation in IBC based on the results of in vitro, in vivo, and patient studies. Current evidence suggests that several major inflammatory signaling pathways are constitutively active in IBC and breast cancer. Among them, the NF-κB, COX-2, and JAK/STAT signaling systems seem to play a major role in the tumorigenesis of IBC. Inflammatory molecules such as interleukin-6, tumor necrosis factor alpha (TNF-α), and gamma interferon have been shown to contribute to malignant transformation in preclinical studies of IBC, while transforming growth factor-β, interleukins 8 and 1β, as well as TNF-α appear to play a role in proliferation, survival, epithelial-mesenchymal transition, invasion, and metastasis. In this chapter, we also describe work thus far involving inhibitors of inflammation in the development of prevention and treatment strategies for IBC.

Evaluation of the expression of stem cell markers in human breast cancer reveals a correlation with clinical progression and metastatic disease in ductal carcinoma

The tumor stem cell theory could explain how patients with metastatic disease show clinical relapse several months after starting treatment due to the survival of a small group of cells with unique characteristics. We examined the distribution and expression of a panel of stem cell markers in human breast cancer primary tumors. Human breast tissues were processed for immunohistochemistry, and RNA was extracted for analysis by quantitative-PCR. Immunohistochemical assay revealed that CD44 was strongly expressed in background endothelia and epithelia. CD133 expression was lost in tumor-associated endothelial cells. Conversely, CD49b was strongly stained in the tumors, associated vessels and ducts but was weakly stained in the background epithelia. q-PCR analysis revealed that CD44 and PSCA were reduced in patients with poor outcome (metastatic disease and death from breast cancer), with a marked reduction in ductal carcinoma, particularly with metastasis to bone although these did not reach significant difference. CD133 was significantly reduced in patients with metastatic disease and was also significantly reduced in patients with ductal carcinoma/bone metastasis. Conversely, CD49F was increased in patients with a poor outcome and those with ductal cancer and bone metastases. This is the first study to determine the distribution and expression pattern of these stem cell markers in human breast cancer. There was a significant association between loss of expression and metastatic disease in patients with breast cancer. Such differential expression may play a part in breast cancer disease progression, and suggests that the current stem cell theory may not hold true for all cancer types.

Immunodetection of cells with a CD44+/CD24- phenotype in canine mammary neoplasms

BACKGROUND

Cancer stem cells (CSCs) are able to self-renew and to form metastases. Using flow cytometry, CSCs were detected in canine mammary tumors as cells CD44(+) and CD24(-). The aim of this study was to detect these CSCs by immunohistochemistry and correlate their frequency with canine mammary neoplasm grade and histopathological type.130 mammary neoplasm samples were selected from tissue blocks at the Department of Pathology at UNESP and classified according to (BJVP 4:153-180, 2011). These samples were composed by adenomas, lymph node metastases, solid carcinomas grades II and III, tubular, papillary and carcinomas in mixed tumor grades I, II and III. Immunohistochemistry was performed with antibodies against CD44 and CD24. Linear regression was performed using Pearson's correlation test.

RESULTS

The value at CD44 was positive and CD24 becomes zero was 46.75%. Cells with a CD44(+)/CD24(-) phenotype were detected in 40 out of 130 samples with an advantage of high grade tumors (II and III) and metastases among tubular, papillary and carcinomas in mixed tumors. In these samples, percentages of cells stained by CD44 and CD24 antibodies were 62.2% and 0%, respectively. Published reports usually correlate grade III tumors with the expression of CD44 but not with CD24 expression. Studies using flow cytometry have found CSC frequencies similar to those found in our study.

CONCLUSIONS

Immunohistochemistry was found to be a reliable technique for the detection of CSCs in canine mammary neoplasms, and the frequency of these cells positively correlates with grades II and III tumors (poor prognosis).

The antihelmintic drug pyrvinium pamoate targets aggressive breast cancer

WNT signaling plays a key role in the self-renewal of tumor initiation cells (TICs). In this study, we used pyrvinium pamoate (PP), an FDA-approved antihelmintic drug that inhibits WNT signaling, to test whether pharmacologic inhibition of WNT signaling can specifically target TICs of aggressive breast cancer cells. SUM-149, an inflammatory breast cancer cell line, and SUM-159, a metaplastic basal-type breast cancer cell line, were used in these studies. We found that PP inhibited primary and secondary mammosphere formation of cancer cells at nanomolar concentrations, at least 10 times less than the dose needed to have a toxic effect on cancer cells. A comparable mammosphere formation IC50 dose to that observed in cancer cell lines was obtained using malignant pleural effusion samples from patients with IBC. A decrease in activity of the TIC surrogate aldehyde dehydrogenase was observed in PP-treated cells, and inhibition of WNT signaling by PP was associated with down-regulation of a panel of markers associated with epithelial-mesenchymal transition. In vivo, intratumoral injection was associated with tumor necrosis, and intraperitoneal injection into mice with tumor xenografts caused significant tumor growth delay and a trend toward decreased lung metastasis. In in vitro mammosphere-based and monolayer-based clonogenic assays, we found that PP radiosensitized cells in monolayer culture but not mammosphere culture. These findings suggest WNT signaling inhibition may be a feasible strategy for targeting aggressive breast cancer. Investigation and modification of the bioavailability and toxicity profile of systemic PP are warranted.

Cyclin D1-dependent induction of luminal inflammatory breast tumors by activated notch3

Accumulating evidence suggests that Notch3 (N3) is involved in breast cancer development, but its precise contributions are not well understood. Here, we report that pregnant mice expressing an activated intracellular form of N3 (N3(IC)) exhibit a cyclin D1-dependent expansion of premalignant CD24(+) CD29(low) luminal progenitors with enhanced differentiation potential in vitro and in vivo. Parous mice developed luminal mammary tumors in a cyclin D1-dependent manner. Notably, mice expressing higher levels of N3(IC) exhibited tumors resembling inflammatory breast cancer that frequently metastasized. N3(IC)-induced tumors contained a large percentage of tumor-initiating cells, but these were reduced significantly in tumors derived from N3(IC) transgenic mice that were heterozygous for cyclin D1. After transplantation in the presence of normal mammary cells, N3(IC)-expressing tumor cells became less malignant, differentiating into CK6(+) CK18(+) CK5(-) alveolar-like structures akin to expanded luminal progenitors from which they were likely derived. Taken together, our results argue that activated N3 signaling primarily affects luminal progenitors among mammary cell subsets, with more pronounced levels of activation influencing tumor type, and provide a novel model of inflammatory breast cancer.

Inflammatory breast cancer (IBC): clues for targeted therapies

Inflammatory breast cancer (IBC) is the most aggressive type of advanced breast cancer characterized by rapid proliferation, early metastatic development and poor prognosis. Since there are few preclinical models of IBC, there is a general lack of understanding of the complexity of the disease. Recently, we have developed a new model of IBC derived from the pleural effusion of a woman with metastatic secondary IBC. FC-IBC02 cells are triple negative and form clusters (mammospheres) in suspension that are strongly positive for E-cadherin, β-catenin and TSPAN24, all adhesion molecules that play an important role in cell migration and invasion. FC-IBC02 cells expressed stem cell markers and some, but not all of the characteristics of cells undergoing epithelial mesenchymal transition (EMT). Breast tumor FC-IBC02 xenografts developed quickly in SCID mice with the presence of tumor emboli and the development of lymph node and lung metastases. Remarkably, FC-IBC02 cells were able to produce brain metastasis in mice on intracardiac or intraperitoneal injections. Genomic studies of FC-IBC02 and other IBC cell lines showed that IBC cells had important amplification of 8q24 where MYC, ATAD2 and the focal adhesion kinase FAK1 are located. MYC and ATAD2 showed between 2.5 and 7 copies in IBC cells. FAK1, which plays important roles in anoikis resistance and tumor metastasis, showed 6–4 copies in IBC cells. Also, CD44 was amplified in triple-negative IBC cells (10–3 copies). Additionally, FC-IBC02 showed amplification of ALK and NOTCH3. These results indicate that MYC, ATAD2, CD44, NOTCH3, ALK and/or FAK1 may be used as potential targeted therapies against IBC.

Inflammatory breast cancer: New factors contribute to disease etiology: A review

Inflammatory breast cancer (IBC) is a highly metastatic and fatal form of breast cancer. In fact, IBC is characterized by specific morphological, phenotypic, and biological properties that distinguish it from non-IBC. The aggressive behavior of IBC being more common among young women and the low survival rate alarmed researchers to explore the disease biology. Despite the basic and translational studies needed to understand IBC disease biology and identify specific biomarkers, studies are limited by few available IBC cell lines, experimental models, and paucity of patient samples. Above all, in the last decade, researchers were able to identify new factors that may play a crucial role in IBC progression. Among identified factors are cytokines, chemokines, growth factors, and proteases. In addition, viral infection was also suggested to participate in the etiology of IBC disease. In this review, we present novel factors suggested by different studies to contribute to the etiology of IBC and the proposed new therapeutic insights.

Mevalonate metabolism regulates Basal breast cancer stem cells and is a potential therapeutic target

There is increasing evidence that breast tumors are organized in a hierarchy, with a subpopulation of tumorigenic cancer cells, the cancer stem cells (CSCs), which sustain tumor growth. The characterization of protein networks that govern CSC behavior is paramount to design new therapeutic strategies targeting this subpopulation of cells. We have sought to identify specific molecular pathways of CSCs isolated from 13 different breast cancer cell lines of luminal or basal/mesenchymal subtypes. We compared the gene expression profiling of cancer cells grown in adherent conditions to those of matched tumorsphere cultures. No specific pathway was identified to be commonly regulated in luminal tumorspheres, resulting from a minor CSC enrichment in tumorsphere passages from luminal cell lines. However, in basal/mesenchymal tumorspheres, the enzymes of the mevalonate metabolic pathway were overexpressed compared to those in cognate adherent cells. Inhibition of this pathway with hydroxy-3-methylglutaryl CoA reductase blockers resulted in a reduction of breast CSC independent of inhibition of cholesterol biosynthesis and of protein farnesylation. Further modulation of this metabolic pathway demonstrated that protein geranylgeranylation (GG) is critical to breast CSC maintenance. A small molecule inhibitor of the geranylgeranyl transferase I (GGTI) enzyme reduced the breast CSC subpopulation both in vitro and in primary breast cancer xenografts. We found that the GGTI effect on the CSC subpopulation is mediated by inactivation of Ras homolog family member A (RHOA) and increased accumulation of P27(kip1) in the nucleus. The identification of protein GG as a major contributor to CSC maintenance opens promising perspectives for CSC targeted therapy in basal breast cancer.