Nuclear factor-kappaB signature of inflammatory breast cancer by cDNA microarray validated by quantitative real-time reverse transcription-PCR, immunohistochemistry, and nuclear factor-kappaB DNA-binding

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.

Inflammatory breast cancer biomarker identification by simultaneous TGIRT-seq profiling of coding and non-coding RNAs in tumors and blood

Inflammatory breast cancer (IBC) is the most aggressive and lethal breast cancer subtype, but lags in biomarker identification. Here, we used an improved Thermostable Group II Intron Reverse Transcriptase RNA sequencing (TGIRT-seq) method to simultaneously profile coding and non-coding RNAs from tumors, PBMCs, and plasma of IBC and non-IBC patients and healthy donors. Besides RNAs from known IBC-relevant genes, we identified hundreds of other overexpressed coding and non-coding RNAs (p≤0.001) in IBC tumors and PBMCs, including higher proportions with elevated intron-exon depth ratios (IDRs), likely reflecting enhanced transcription resulting in accumulation of intronic RNAs. As a consequence, differentially represented protein-coding gene RNAs in IBC plasma were largely intron RNA fragments, whereas those in healthy donor and non-IBC plasma were largely fragmented mRNAs. Potential IBC biomarkers in plasma included T-cell receptor pre-mRNA fragments traced to IBC tumors and PBMCs; intron RNA fragments correlated with high IDR genes; and LINE-1 and other retroelement RNAs that we found globally up-regulated in IBC and preferentially enriched in plasma. Our findings provide new insights into IBC and demonstrate advantages of broadly analyzing transcriptomes for biomarker identification. The RNA-seq and data analysis methods developed for this study may be broadly applicable to other diseases.

The role of NF-κB in breast cancer initiation, growth, metastasis, and resistance to chemotherapy

Breast cancer (BC) is the second most fatal disease and is the prime cause of cancer allied female deaths. BC is caused by aberrant tumor suppressor genes and oncogenes regulated by transcription factors (TFs) like NF-κB. NF-κB is a pro-inflammatory TF that crucially alters the expressions of various genes associated with inflammation, cell progression, metastasis, and apoptosis and modulates a network of genes that underlie tumorigenesis. Herein, we focus on NF-κB signaling pathways, its regulators, and the rationale for targeting NF-κB. This review also includes TFs that maintain NF-κB crosstalk and their roles in promoting angiogenesis and metastasis. In addition, we discuss the importance of combination therapies, resistance to treatment, and potential novel therapeutic strategies including nanomedicine that targets NF-κB.

Metadherin Regulates Inflammatory Breast Cancer Invasion and Metastasis

Inflammatory breast cancer (IBC) is one of the most lethal subtypes of breast cancer (BC), accounting for approximately 1-5% of all cases of BC. Challenges in IBC include accurate and early diagnosis and the development of effective targeted therapies. Our previous studies identified the overexpression of metadherin (MTDH) in the plasma membrane of IBC cells, further confirmed in patient tissues. MTDH has been found to play a role in signaling pathways related to cancer. However, its mechanism of action in the progression of IBC remains unknown. To evaluate the function of MTDH, SUM-149 and SUM-190 IBC cells were edited with CRISPR/Cas9 vectors for in vitro characterization studies and used in mouse IBC xenografts. Our results demonstrate that the absence of MTDH significantly reduces IBC cell migration, proliferation, tumor spheroid formation, and the expression of NF-κB and STAT3 signaling molecules, which are crucial oncogenic pathways in IBC. Furthermore, IBC xenografts showed significant differences in tumor growth patterns, and lung tissue revealed epithelial-like cells in 43% of wild-type (WT) compared to 29% of CRISPR xenografts. Our study emphasizes the role of MTDH as a potential therapeutic target for the progression of IBC.

Adaptive stress response genes associated with breast cancer subtypes and survival outcomes reveal race-related differences

Aggressive breast cancer variants, like triple negative and inflammatory breast cancer, contribute to disparities in survival and clinical outcomes among African American (AA) patients compared to White (W) patients. We previously identified the dominant role of anti-apoptotic protein XIAP in regulating tumor cell adaptive stress response (ASR) that promotes a hyperproliferative, drug resistant phenotype. Using The Cancer Genome Atlas (TCGA), we identified 46-88 ASR genes that are differentially expressed (2-fold-change and adjusted p-value < 0.05) depending on PAM50 breast cancer subtype. On average, 20% of all 226 ASR genes exhibited race-related differential expression. These genes were functionally relevant in cell cycle, DNA damage response, signal transduction, and regulation of cell death-related processes. Moreover, 23% of the differentially expressed ASR genes were associated with AA and/or W breast cancer patient survival. These identified genes represent potential therapeutic targets to improve breast cancer outcomes and mitigate associated health disparities.

Comparative transcriptional analyses of preclinical models and patient samples reveal MYC and RELA driven expression patterns that define the molecular landscape of IBC

Inflammatory breast cancer (IBC) is an aggressive disease for which the spectrum of preclinical models was rather limited in the past. More recently, novel cell lines and xenografts have been developed. This study evaluates the transcriptome of an extended series of IBC preclinical models and performed a comparative analysis with patient samples to determine the extent to which the current models recapitulate the molecular characteristics of IBC observed clinically. We demonstrate that the IBC preclinical models are exclusively estrogen receptor (ER)-negative and of the basal-like subtype, which reflects to some extent the predominance of these subtypes in patient samples. The IBC-specific 79-signature we previously reported was retrained and discriminated between IBC and non-IBC preclinical models, but with a relatively high rate of false positive predictions. Further analyses of gene expression profiles revealed important roles for cell proliferation, MYC transcriptional activity, and TNFɑ/NFκB in the biology of IBC. Patterns of MYC expression and transcriptional activity were further explored in patient samples, which revealed interactions with ESR1 expression that are contrasting in IBC and nIBC and notable given the comparatively poor outcomes of ER+ IBC. Our analyses also suggest important roles for NMYC, MXD3, MAX, and MLX in shaping MYC signaling in IBC. Overall, we demonstrate that the IBC preclinical models can be used to unravel cancer cell intrinsic molecular features, and thus constitute valuable research tools. Nevertheless, the current lack of ER-positive IBC models remains a major hurdle, particularly since interactions with the ER pathway appear to be relevant for IBC.

ERα-dependent estrogen-TNFα signaling crosstalk increases cisplatin tolerance and migration of lung adenocarcinoma cells

Lung adenocarcinoma is the most common type of lung cancer in women. Our previous studies demonstrated that 17β-estradiol (E2) promoted lung adenocarcinoma cell proliferation and tumor growth through estrogen receptor ERα. Transcriptomic analysis suggested that E2 potentiated TNFα-NFκB signaling in ERα-expressing lung adenocarcinoma cells. This study further demonstrated that E2 increased TNFα receptor expression and TNFα-triggered NFκB activity in ERα-expressing cells. E2-activated ERα had no physical association with NFκB p65/p50 heterodimer but facilitated TNFα-initiated IκBα degradation, NFκB nuclear translocation, and S468/S536 phosphorylation of p65 essential for NFκB activity. While knockdown of ERα prevented E2 from boosting NFκB activity, antiestrogen ICI 182,780 stimulated NFκB activity like E2. Inhibition of GSK3β hampered E2:ERα-promoted NFκB activity and abolished S468 phosphorylation of p65, suggesting that GSK3β played a role in the E2-TNFα signaling crosstalk. In ERα-expressing cells, E2 and TNFα synergistically regulated many genes that were not typically responsive to either E2 or TNFα. Functional analysis of microarray data inferred that E2/TNFα-induced transcriptomic changes improved cell survival and movement. Viability and colony formation assays validated that E2 and TNFα together increased cisplatin tolerance of ERα-expressing cells. Wound healing assays also confirmed that E2/TNFα cotreatment increased cell migration in an ERα-dependent manner. E2/TNFα-induced dysregulation of genes such as cell survival and movement-associated genes, proto-oncogenes, metallothioneins and histone core genes was correlated with poor overall survival in patients. In summary, E2 and TNFα engaged in an ERα-dependent positive crosstalk in lung adenocarcinoma cells, consequently increasing NFκB activation, cisplatin tolerance and cell migration and worsening prognosis.

Immune landscape of inflammatory breast cancer suggests vulnerability to immune checkpoint inhibitors

Background. Anti-PD1/PDL1 immune checkpoint inhibitors (ICIs) showed promising results in breast cancer, and exploration of additional actionable immune checkpoints is ongoing. Inflammatory breast cancer (IBC) is an aggressive form of disease, the immune tumor microenvironment (TME) of which is poorly known. We aimed at providing the first comprehensive immune portrait of IBCs. Methods. From the gene expression profiles of 137 IBC and 252 non-IBC clinical samples, we measured the fractions of 22 immune cell types, expression of signatures associated with tertiary lymphoid structures (TLS) and with the response to ICIs (T cell-inflamed signature: TIS) and of 18 genes coding for major actionable immune checkpoints. The IBC/non-IBC comparison was adjusted upon the clinicopathological variables. Results. The immune profiles of IBCs were heterogeneous. CIBERSORT analysis showed profiles rich in macrophages, CD8+ and CD4 + T-cells, with remarkable similarity with melanoma TME. The comparison with non-IBCs showed significant enrichment in M1 macrophages, γδ T-cells, and memory B-cells. IBCs showed higher expression of TLS and TIS signatures. The TIS signature displayed values in IBCs close to those observed in other cancers sensitive to ICIs. Two-thirds of actionable immune genes (HAVCR2/TIM3, CD27, CD70, CTLA4, ICOS, IDO1, LAG3, PDCD1, TNFRSF9, PVRIG, CD274/PDL1, and TIGIT) were overexpressed in IBCs as compared to normal breast and two-thirds were overexpressed in IBCs versus non-IBCs, with very frequent co-overexpression. For most of them, the overexpression was associated with better pathological response to chemotherapy. Conclusion. Our results suggest the potential higher vulnerability of IBC to ICIs. Clinical trials.

Update on the Role of NFκB in Promoting Aggressive Phenotypes of Estrogen Receptor-Positive Breast Cancer

The majority of breast cancers are diagnosed as estrogen receptor-positive (ER+) and respond well to ER-targeted endocrine therapy. Despite the initial treatability of ER+ breast cancer, this subtype still accounts for the majority of deaths. This is partly due to the changing molecular characteristics of tumors as they progress to aggressive, metastatic, and frequently therapy resistant disease. In these advanced tumors, targeting ER alone is often less effective, as other signaling pathways become active, and ER takes on a redundant or divergent role. One signaling pathway whose crosstalk with ER has been widely studied is the nuclear factor kappa B (NFκB) signaling pathway. NFκB is frequently implicated in ER+ tumor progression to an aggressive disease state. Although ER and NFκB frequently co-repress each other, it has emerged that the 2 pathways can positively converge to play a role in promoting endocrine resistance, metastasis, and disease relapse. This will be reviewed here, paying particular attention to new developments in the field. Ultimately, finding targeted therapies that remain effective as tumors progress remains one of the biggest challenges for the successful treatment of ER+ breast cancer. Although early attempts to therapeutically block NFκB activity frequently resulted in systemic toxicity, there are some effective options. The drugs parthenolide and dimethyl fumarate have both been shown to effectively inhibit NFκB, reducing tumor aggressiveness and reversing endocrine therapy resistance. This highlights the need to revisit targeting NFκB in the clinic to potentially improve outcome for patients with ER+ breast cancer.

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 Intracellular Components of the NF-κB Alternative Pathway (NF-κB2, RelB, NIK and Bcl3) is Associated With Clinical Outcome of NSCLC Patients

A growing number of studies has shed light on the role of the NF-κΒ in non-small-cell lung cancer (NSCLC). To address the significance of major effectors of the NF-κΒ alternative pathway, we investigated the relationship between NF-κΒ2, RelB, NIK and Bcl3 expression (mRNA and protein) and the clinical outcome of NSCLC patients. NF-κΒ2, RelB, NIK and Bcl3 protein expression levels were assessed by immunohistochemistry in tissue samples from 151 NSCLC patients who had curative resection. mRNA levels were also evaluated in 69 patients using quantitative real-time PCR. Although all studied proteins were overexpressed in NSCLC (P < 0.001 for all), only RelB mRNA levels were strongly increased in cancerous specimens compared to tumor-adjacent non-neoplastic tissues (P = 0.009). Moreover, NF-κB2, RelB and Bcl3 expression was associated with overall survival (OS). In particular, cytoplasmic and mRNA expression of RelB was related to 5-year OS (P = 0.014 and P = 0.006, respectively). Multivariate analysis also showed that Bcl3 expression (nuclear and cytoplasmic) was associated with increased 5-year OS (P = 0.002 and P = 0.036, respectively). In addition, higher Bcl3 mRNA levels were associated with inferior OS in stages I & II and improved OS in stages III and IV after 5-year follow-up (P = 0.004 and P = 0.001, respectively). Furthermore, stage I patients with lower NF-κB2 mRNA levels had better 5-year survival in univariate and multivariate analysis (P = 0.031 and P = 0.028, respectively). Interestingly, RelB expression (cytoplasmic and mRNA) was inversely associated with relapse rates (P = 0.027 and P = 0.015, respectively), while low NIK cytoplasmic expression was associated with lower relapse rates (P = 0.019). Cytoplasmic NIK expression as well as NF-κB2/ Bcl3 detection was associated with lymph node infiltration (P = 0.039 and P = 0.014, respectively). The present study confirms the deregulation of the NF-κB alternative pathway in NSCLC and also demonstrates the importance of this pathway in prognosis, recurrence and infiltration of regional lymph nodes.

Differential impact of classical and non-canonical NF-κB pathway-related gene expression on the survival of breast cancer patients

Inflammation is a well-known driver of carcinogenesis and cancer progression, often attributed to the tumor microenvironment. However, tumor cells themselves are capable of secreting a variety of inflammatory molecules, leading to the activation of specific signaling pathways that promote tumor progression. The NF-κB signaling pathway is one of the most important connections between inflammation and tumorigenesis. NF-κB is a superfamily of transcription factors that plays an important role in several types of hematological and solid tumors, including breast cancer. However, the role of the NF-κB pathway in the survival of breast cancer patients is poorly studied. In this study, we analyzed and related the expression of both canonical and alternative NF-κB pathways and selected target genes with the relapse-free and overall survival of breast cancer patients. We used the public database Kaplan-Meier plotter (KMplot) which includes gene expression data and survival information of 3951 breast cancer patients. We found that the expression of IKKα was associated with poor relapse-free survival in patients with ER-positive tumors. Moreover, the expression of IL-8 and MMP-1 was associated with poor relapse-free and overall survival. In contrast, expression of IKKβ, p50, and p65 from the canonical pathway, and NIK and RELB from the alternative pathway correlated with better relapse-free survival also when the patients were classified by their hormonal and nodal status. Our study suggests that the expression of genes of the canonical and alternative NF-κB pathways is ultimately critical for tumor persistence. Understanding the communication between both pathways would help to find better therapeutic and prophylactic targets to prevent breast cancer progression and relapse.

The effects of Curcuma longa and curcumin on reproductive systems

OBJECTIVE

Curcuma longa (C. longa) was used in some countries such as China and India for various medicinal purposes. Curcumin, the active component of C. longa, is commonly used as a coloring agent in foods, drugs, and cosmetics. C. longa and curcumin have been known to act as antioxidant, anti-inflammatory, anti-mutagen, and anti-carcinogenic agents. Th e attempt of the present review was to give an effort on a detailed literature survey concentrated on the protective effects of C. longa and curcumin on the reproductive organs activity.

METHODS

The databases such as, PubMed, Web of Science, Google Scholar, Scopus, and Iran- Medex, were considered. The search terms were "testis" or "ovary" and "Curcuma longa", "curcumin", "antioxidant effect", "anti-inflammatory effect" and "anti-cancer effect".

RESULTS

C. longa and curcumin inhibited the production of the tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) and increased the caspases (3, 8 and 9) activities in HL-60 prostate cancer. Furthermore, C. longa and curcumin suppressed the vascular endothelial growth factor (VEGF), phosphorylated signal transducers and activators of the transcription 3 (STAT) and matrix metalloproteinase-9 (MMP-9) in ovarian cancer cell line.

CONCLUSION

C. longa and curcumin might decrease the risk of cancer and other malignant diseases in the reproductive system. C. longa and curcumin have a protective effect on the reproductive organs activity such as, anti-inflammatory, anti-apoptotic, and antioxidant effects in normal cells but showed pro-apoptotic effects in the malignant cells. Therefore, different effects of C. longa and curcumin are dependent on the doses and the type of cells used in various models studied.

ERα upregulates the expression of long non-coding RNA LINC00472 which suppresses the phosphorylation of NF-κB in breast cancer

PURPOSE

Low expression of long intergenic non-coding RNA LINC00472 in breast cancer is associated with aggressive tumors and unfavorable disease outcomes in multiple clinical datasets, but the reasons for these associations were unknown.

METHODS

To study the mechanisms underlying the lncRNA's connection to breast cancer, we investigated the molecular targets and regulation of LINC00472 in breast cancer cells, and analyzed relevant molecular features in relation to patient survival. Gene expression profiles of breast cancer cells overexpressing LINC00472 were analyzed for its regulatory pathways and downstream targets. Effects of LINC00472 overexpression on cell behaviors were evaluated in vitro and in vivo. Meta-analysis was performed using online datasets and our own study.

RESULTS

Analysis of LINC00472 transcriptome revealed ERα upregulation of LINC00472 expression, and an ERα-binding site in the LINC00472 promoter was identified. Evaluation of LINC00472 overexpression also indicated a possible link between LINC00472 and NF-κB. Cell experiments confirmed that LINC00472 suppressed the phosphorylation of p65 and IκBα through binding to IKKβ, inhibiting its phosphorylation. High LINC00472 expression inhibited tumor growth both in vitro and in vivo and suppressed aggressive tumor cell behaviors in vitro. Suppressing LINC00472 expression in ER-positive tumor cells increased cell aggressive behaviors. Tamoxifen treatment of ER-positive cells inhibited ERα and LINC00472 expression and increased p65 and IκBα phosphorylation. Meta-analysis showed that LINC00472 expression were higher in ER-positive than ER-negative tumors and that high expression was associated with better disease outcomes in ER-positive patients.

CONCLUSIONS

The study demonstrates that ERα upregulates LINC00472 which suppresses the phosphorylation of NF-κB, and suggests that endocrine treatment may lower LINC00472 and increase NF-κB activities, leading to tumor progression and disease recurrence.

Enabling precision medicine by unravelling disease pathophysiology: quantifying signal transduction pathway activity across cell and tissue types

Signal transduction pathways are important in physiology and pathophysiology. Targeted drugs aim at modifying pathogenic pathway activity, e.g., in cancer. Optimal treatment choice requires assays to measure pathway activity in individual patient tissue or cell samples. We developed a method enabling quantitative measurement of functional pathway activity based on Bayesian computational model inference of pathway activity from measurements of mRNA levels of target genes of the pathway-associated transcription factor. Oestrogen receptor, Wnt, and PI3K-FOXO pathway assays have been described previously. Here, we report model development for androgen receptor, Hedgehog, TGFβ, and NFκB pathway assays, biological validation on multiple cell types, and analysis of data from published clinical studies (multiple sclerosis, amyotrophic lateral sclerosis, contact dermatitis, Ewing sarcoma, lymphoma, medulloblastoma, ependymoma, skin and prostate cancer). Multiple pathway analysis of clinical prostate cancer (PCa) studies showed increased AR activity in hyperplasia and primary PCa but variable AR activity in castrate resistant (CR) PCa, loss of TGFβ activity in PCa, increased Wnt activity in TMPRSS2:ERG fusion protein-positive PCa, active PI3K pathway in advanced PCa, and active PI3K and NFκB as potential hormonal resistance pathways. Potential value for future clinical practice includes disease subtyping and prediction and targeted therapy response prediction and monitoring.

RIPK2: New Elements in Modulating Inflammatory Breast Cancer Pathogenesis

Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer that is associated with significantly high mortality. In spite of advances in IBC diagnoses, the prognosis is still poor compared to non-IBC. Due to the aggressive nature of the disease, we hypothesize that elevated levels of inflammatory mediators may drive tumorigenesis and metastasis in IBC patients. Utilizing IBC cell models and patient tumor samples, we can detect elevated NF-κB activity and hyperactivation of non-canonical drivers of NF-κB (nuclear factor kappaB)-directed inflammation such as tyrosine phosphorylated receptor-interacting protein kinase 2 (pY RIPK2), when compared to non-IBC cells or patients. Interestingly, elevated RIPK2 activity levels were present in a majority of pre-chemotherapy samples from IBC patients at the time of diagnosis to suggest that patients at diagnosis had molecular activation of NF-κB via RIPK2, a phenomenon we define as “molecular inflammation”. Surprisingly, chemotherapy did cause a significant increase in RIPK2 activity and thus molecular inflammation suggesting that chemotherapy does not resolve the molecular activation of NF-κB via RIPK2. This would impact on the metastatic potential of IBC cells. Indeed, we can demonstrate that RIPK2 activity correlated with advanced tumor, metastasis, and group stage as well as body mass index (BMI) to indicate that RIPK2 might be a useful prognostic marker for IBC and advanced stage breast cancer.

Immunity drives TET1 regulation in cancer through NF-κB

Ten-eleven translocation enzymes (TET1, TET2, and TET3), which induce DNA demethylation and gene regulation by converting 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), are often down-regulated in cancer. We uncover, in basal-like breast cancer (BLBC), genome-wide 5hmC changes related to TET1 regulation. We further demonstrate that TET1 repression is associated with high expression of immune markers and high infiltration by immune cells. We identify in BLBC tissues an anticorrelation between TET1 expression and the major immunoregulator family nuclear factor κB (NF-κB). In vitro and in mice, TET1 is down-regulated in breast cancer cells upon NF-κB activation through binding of p65 to its consensus sequence in the TET1 promoter. We lastly show that these findings extend to other cancer types, including melanoma, lung, and thyroid cancers. Together, our data suggest a novel mode of regulation for TET1 in cancer and highlight a new paradigm in which the immune system can influence cancer cell epigenetics.

Inflammatory breast cancer tumor emboli express high levels of anti-apoptotic proteins: use of a quantitative high content and high-throughput 3D IBC spheroid assay to identify targeting strategies

Inflammatory breast cancer (IBC) is one of the most lethal breast cancer variants; with existing therapy, 5-yr survival rate is only 35%. Current barriers to successful treatment of IBC include frequent infiltration and the presence of tumor cell clusters, termed tumor emboli, within the breast parenchyma and lymphatics. Prior studies have identified the role of anti-apoptotic signaling, in particular hyperactivation of NFκB and its target genes, in IBC pathobiology and therapeutic resistance. The objectives of this study were to: (1) determine if IBC tumor emboli express anti-apoptotic proteins and (2) develop a high content, multiparametric assay to assess the morphology of the IBC 3D spheroids and to optimize a high throughput format to screen for compounds that can inhibit the formation of the IBC tumor clusters/embolic structures. Immunohistochemical analysis of IBC patient tumor samples with documented tumor emboli revealed high NFκB (p65) staining along with expression of XIAP, a potent anti-apoptotic protein known to interact with NFκB signaling in enhancing survival of malignant cells. Subsequently, the high content assay developed allowed for simultaneous imaging and morphometric analysis, including count and viability of spheroids derived from SUM149, rSUM149 and SUM190 cells and its application to evaluate XIAP and NFκB inhibitory agents. We demonstrate the efficacy of the off-patent drug disulfiram when chelated with copper, which we had previously reported to inhibit NFκB signaling, was highly effective in disrupting both IBC spheroids and emboli grown in vitro. Taken together, these results identify a high-throughput approach to target tumor spheroid formation for drug discovery. Finally, disulfiram is a safe and approved drug for management of alcohol abuse, warranting its evaluation for repurposing in IBC therapy.

Bisphenol A activates EGFR and ERK promoting proliferation, tumor spheroid formation and resistance to EGFR pathway inhibition in estrogen receptor-negative inflammatory breast cancer cells

Emerging evidence from epidemiological studies suggests a link between environmental chemical exposure and progression of aggressive breast cancer subtypes. Of all clinically distinct types of breast cancers, the most lethal phenotypic variant is inflammatory breast cancer (IBC). Overexpression of epidermal growth factor receptors (EGFR/HER2) along with estrogen receptor (ER) negativity is common in IBC tumor cells, which instead of a solid mass present as rapidly proliferating diffuse tumor cell clusters. Our previous studies have demonstrated a role of an adaptive response of increased antioxidants in acquired resistance to EGFR-targeting drugs in IBC. Environmental chemicals are known to induce oxidative stress resulting in perturbations in signal transduction pathways. It is therefore of interest to identify chemicals that can potentiate EGFR mitogenic effects in IBC. Herein, we assessed in ER-negative IBC cells a subset of chemicals from the EPA ToxCast set for their effect on EGFR activation and in multiple cancer phenotypic assays. We demonstrated that endocrine-disrupting chemicals such as bisphenol A (BPA) and 2,2-bis(p-hydroxyphenyl)-1,1,1-trichloroethane can increase EGFR/ERK signaling. BPA also caused a corresponding increase in expression of SOD1 and anti-apoptotic Bcl-2, key markers of antioxidant and anti-apoptotic processes. BPA potentiated clonogenic growth and tumor spheroid formation in vitro, reflecting IBC-specific pathological characteristics. Furthermore, we identified that BPA was able to attenuate the inhibitory effect of an EGFR targeted drug in a longer-term anchorage-independent growth assay. These findings provide a potential mechanistic basis for environmental chemicals such as BPA in potentiating a hyperproliferative and death-resistant phenotype in cancer cells by activating mitogenic pathways to which the tumor cells are addicted for survival.

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.

Intermittent hypoxia confers pro-metastatic gene expression selectively through NF-κB in inflammatory breast cancer cells

Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer. Treatment options are limited and the mechanisms underlying its aggressiveness are poorly understood. Intermittent hypoxia (IH) causes oxidative stress and is emerging as important regulator of tumor metastasis. Vessels in IBC tumors have been shown to be immature, which is a primary cause of IH. We therefore investigated the relevance of IH for the modulation of gene expression in IBC cells in order to assess IH as potential regulator of IBC aggressiveness. Gene array analysis of IBC cells following chronic IH (45-60 days) demonstrated increased expression of pro-metastatic genes of the extracellular matrix, such as tenascin-C (TNC; an essential factor of the metastatic niche) and matrix metalloproteinase 9 (MMP9), and of pro-inflammatory processes, such as cyclooxygenase-2 (COX-2). Investigating the oxidative stress-dependent regulation of TNC, we found a gradual sensitivity on mRNA and protein levels. Oxidative stress activated NF-E2-related factor 2 (Nrf2), c-Jun N-terminal kinase (JNK), c-Jun and nuclear factor κB (NF-κB), but TNC upregulation was only dependent on NF-κB activation. Pharmacological inhibition of inhibitor of NF-κB α (IκBα) phosphorylation as well as overexpression of IκBα prevented TNC, MMP9 and COX-2 induction, whereas the pro-inflammatory cytokine interleukin-1β (IL-1β) increased their expression levels. Analysis of the gene array data showed NF-κB binding sites for 64% of all upregulated genes, linking NF-κB with IH-dependent regulation of pro-metastatic gene expression in IBC cells. Our results provide a first link between intermittent hypoxia and pro-metastatic gene expression in IBC cells, revealing a putative novel mechanism for the high metastatic potential of IBC.

Luteolin protects mice from severe acute pancreatitis by exerting HO-1-mediated anti-inflammatory and antioxidant effects

Reseda odorata L. has long been used in traditional Asian medicine for the treatment of diseases associated with oxidative injury and acute inflammation, such as endotoxemia, acute lung injury, acute myocardial infarction and hepatitis. Luteolin, the main component of Reseda odorata L., which is also widely found in many natural herbs and vege-tables, has been shown to induce heme oxygenase-1 (HO-1) expression to exert anti-inflammatory and antioxidant effects. In this study, we aimed to examine the effects of luteolin on mice with severe acute pancreatitis (SAP), and to explore the underlying mechanisms. Cerulein and lipopolysaccharide were used to induce SAP in male Institute of Cancer Research (ICR) mice in the SAP group. The SAP group was divided into 4 subgroups, as follows: the vehicle, luteolin, zinc protoporphyrin (ZnPP) only, and luteolin (Lut) + ZnPP (luteolin plus zinc protoporphyrin treatment) groups. The wet/dry weight ratios, hematoxylin and eosin staining and pathological scores of pancreatic tissues were assessed and compared to those of the control mice. Amylase, lipase, nuclear factor-κB (NF-κB) and myeloperoxidase activities, and malondialdehyde, tumor necrosis factor α (TNFα), interleukin (IL)-6, IL-10 and HO-1 levels, as well as the expression of HO-1 were determined in serum and/or pancreatic tissue samples. SAP was successfully induced in male mice compared to normal control mice. The wet/dry weight ratios, pathological scores, and amylase and lipase activity, as well as the levels of TNFα and IL-6 were significantly reduced in the pancreatic tissues of the mice in the Lut group compared with those of the mice in the vehicle group. The Lut group exhibited a significant increase in HO-1 expression in the pancreas and enhanced serum HO-1 and IL-10 levels compared with the vehicle group. The suppression of HO-1 activity in the ZnPP group significantly abolished the protective effects of luteolin. NF-κB expression in the pancreatic tissues from the mice in the Lut + ZnPP group was significantly increased following the suppression of HO-1 activity. On the whole, our findings demonstrate that luteolin protects mice from SAP by inducing HO-1-mediated anti-inflammatory and antioxidant activities, in association with the suppression of the activation of the NF-κB pathway.

Non-Canonical EZH2 Transcriptionally Activates RelB in Triple Negative Breast Cancer

Enhancer of zeste homology 2 (EZH2) is the methyltransferase component of the polycomb repressive complex (PRC2) which represses gene transcription via histone H3 trimethylation at lysine 23 (H3K27me3). EZH2 activity has been linked with oncogenesis where it is thought to block expression of certain tumor suppressors. Relative to a role in cancer, EZH2 functions to promote self-renewal and has been shown to be important for the tumor-initiating cell (TIC) phenotype in breast cancer. Recently a non-canonical role for EZH2 has been identified where it promotes transcriptional activation of certain genes. Here we show that EZH2, through a methyltransferase-independent mechanism, promotes the transcriptional activation of the non-canonical NF-κB subunit RelB to drive self-renewal and the TIC phenotype of triple-negative breast cancer cells.

Non-canonical NF-κB pathway activation predicts outcome in borderline oestrogen receptor positive breast carcinoma

Background:

NF-κB signalling appears deregulated in breast tumours. The purpose of this study was to determine whether the non-canonical NF-κB pathway, is activated in oestrogen receptor positive (ER+) breast cancer, to identify any correlation between its activity and the clinico-pathological phenotype and to explore whether NF-κB2 and RelB subunits and/or any of their target genes might be used as a predictive marker.

Methods:

Two independent cohorts of ER+ early breast cancer patients treated with adjuvant endocrine therapy were included in the study. Activation of RelB and NF-κB2 subunits was determined in a training set of 121 patients by measuring DNA-binding activities in nuclear extracts from fresh frozen specimens by an ELISA-based assay. Samples of 15 ER− breast cancer patients were also included in the study. In a large validation cohort of 207 patients, nuclear immunostaining of RelB and NF-κB2 on formalin-fixed paraffin-embedded specimens was performed. Statistical correlation within clinico-pathological factors, disease-free survival (DFS) and overall survival (OS) was evaluated. Publicly available gene expression and survival data have been interrogated aimed to identify target genes.

Results:

Activation of NF-κB2 and RelB was found in 53.7 and 49.2% of the 121 ER+ tumours analysed, with similar levels to ER− breast tumours analysed in parallel for comparisons. In the validation cohort, we obtained a similar proportion of cases with activation of NF-κB2 and RelB (59.9 and 32.4%), with a 39.6% of co-activation. Multiplexing immunofluorescence in breast cancer tissue confirmed an inverse spatial distribution of ER with NF-κB2 and RelB nuclear expression in tumour cells. Interestingly, NF-κB2 and RelB mRNA expression was inversely correlated with ER gene (ESR1) levels (P<0.001, both) and its activation was significantly associated with worse DFS (P=0.005 and P=0.035, respectively) in ER+ breast cancer. Moreover, the co-activation of both subunits showed a stronger association with early relapse (P=0.002) and OS (P=0.001). Finally, higher expression of the non-canonical NF-κB target gene myoglobin was associated with a poor outcome in ER+ breast cancer (DFS, P<0.05).

Conclusions:

The non-canonical NF-κB pathway activation is inversely associated with oestrogen receptor expression in ER+ breast cancer and predicts poor survival in this subgroup. The myoglobin gene expression has been identified as a possible surrogate marker of the non-canonical NF-κB pathway activation in these tumours.

Genomic and Immunological Tumor Profiling Identifies Targetable Pathways and Extensive CD8+/PDL1+ Immune Infiltration in Inflammatory Breast Cancer Tumors

Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer that remains poorly understood at the molecular level. Comprehensive tumor profiling was performed to understand clinically actionable alterations in IBC. Targeted next-generation sequencing (NGS) and IHC were performed to identify activated pathways in IBC tumor tissues. siRNA studies examined the impact of IBC genomic variants in cellular models. IBC tumor tissues were further characterized for immune infiltration and immune checkpoint expression by IHC. Genomic analysis identified recurrent alterations in core biologic pathways, including activating and targetable variants in HER/PI3K/mTOR signaling. High rates of activating HER3 point mutations were discovered in IBC tumors. Cell line studies confirmed a role for mutant HER3 in IBC cell proliferation. Immunologic analysis revealed a subset of IBC tumors associated with high CD8(+)/PD-L1(+) lymphocyte infiltration. Immune infiltration positively correlated with an NGS-based estimate of neoantigen exposure derived from the somatic mutation rate and mutant allele frequency, iScore. Additionally, DNA mismatch repair alterations, which may contribute to higher iScores, occurred at greater frequency in tumors with higher immune infiltration. Our study identifies genomic alterations that mechanistically contribute to oncogenic signaling in IBC and provides a genetic basis for the selection of clinically relevant targeted and combination therapeutic strategies. Furthermore, an NGS-based estimate of neoantigen exposure developed in this study (iScore) may be a useful biomarker to predict immune infiltration in IBC and other cancers. The iScore may be associated with greater levels of response to immunotherapies, such as PD-L1/PD-1-targeted therapies. Mol Cancer Ther; 15(7); 1746-56. ©2016 AACR.

NFκB affects estrogen receptor expression and activity in breast cancer through multiple mechanisms

Estrogen receptor (ER) and NFκB are two widely expressed, pleiotropic transcription factors that have been shown to interact and affect one another's activity. While the ability of ER to repress NFκB activity has been extensively studied and is thought to underlie the anti-inflammatory activity of estrogens, how NFκB signaling affects ER activity is less clear. This is a particularly important question in breast cancer since activation of NFκB in ER positive tumors is associated with failure of endocrine and chemotherapies. In this review, we provide an update on the multiple mechanisms by which NFκB can influence ER activity, including down-regulation of ER expression, enhanced ER recruitment to DNA, and increased transcriptional activity of both liganded and unliganded ER. Additionally, a novel example of NFκB potentiation of ER-dependent gene repression is reviewed. Together, these mechanisms can alter response to endocrine therapies and may underlie the poor outcome for women with ER positive tumors that have active NFκB signaling.

Decreased expression of ABAT and STC2 hallmarks ER-positive inflammatory breast cancer and endocrine therapy resistance in advanced disease

BACKGROUND

Patients with Estrogen Receptor α-positive (ER+) Inflammatory Breast Cancer (IBC) are less responsive to endocrine therapy compared with ER+ non-IBC (nIBC) patients. The study of ER+ IBC samples might reveal biomarkers for endocrine resistant breast cancer.

MATERIALS & METHODS

Gene expression profiles of ER+ samples from 201 patients were explored for genes that discriminated between IBC and nIBC. Classifier genes were applied onto clinically annotated expression data from 947 patients with ER+ breast cancer and validated with RT-qPCR for 231 patients treated with first-line tamoxifen. Relationships with metastasis-free survival (MFS) and progression-free survival (PFS) following adjuvant and first-line endocrine treatment, respectively, were investigated using Cox regression analysis.

RESULTS

A metagene of six genes including the genes encoding for 4-aminobutyrate aminotransferase (ABAT) and Stanniocalcin-2 (STC2) were identified to distinguish 22 ER+ IBC from 43 ER+ nIBC patients and remained discriminatory in an independent series of 136 patients. The metagene and two genes were not prognostic in 517 (neo)adjuvant untreated lymph node-negative ER+ nIBC breast cancer patients. Only ABAT was related to outcome in 250 patients treated with adjuvant tamoxifen. Three independent series of in total 411 patients with advanced disease showed increased metagene scores and decreased expression of ABAT and STC2 to be correlated with poor first-line endocrine therapy outcome. The biomarkers remained predictive for first-line tamoxifen treatment outcome in multivariate analysis including traditional factors or published signatures. In an exploratory analysis, ABAT and STC2 protein expression levels had no relation with PFS after first-line tamoxifen.

CONCLUSIONS

This study utilized ER+ IBC to identify a metagene including ABAT and STC2 as predictive biomarkers for endocrine therapy resistance.

Disulfiram (DSF) acts as a copper ionophore to induce copper-dependent oxidative stress and mediate anti-tumor efficacy in inflammatory breast cancer

Cancer cells often have increased levels of reactive oxygen species (ROS); however, acquisition of redox adaptive mechanisms allows for evasion of ROS-mediated death. Inflammatory breast cancer (IBC) is a distinct, advanced BC subtype characterized by high rates of residual disease and recurrence despite advances in multimodality treatment. Using a cellular model of IBC, we identified an oxidative stress response (OSR) signature in surviving IBC cells after administration of an acute dose of an ROS inducer. Metagene analysis of patient samples revealed significantly higher OSR scores in IBC tumor samples compared to normal or non-IBC tissues, which may contribute to the poor response of IBC tumors to common treatment strategies, which often rely heavily on ROS induction. To combat this adaptation, we utilized a potent redox modulator, the FDA-approved small molecule Disulfiram (DSF), alone and in combination with copper. DSF forms a complex with copper (DSF-Cu) increasing intracellular copper concentration both in vitro and in vivo, bypassing the need for membrane transporters. DSF-Cu antagonized NFκB signaling, aldehyde dehydrogenase activity and antioxidant levels, inducing oxidative stress-mediated apoptosis in multiple IBC cellular models. In vivo, DSF-Cu significantly inhibited tumor growth without significant toxicity, causing apoptosis only in tumor cells. These results indicate that IBC tumors are highly redox adapted, which may render them resistant to ROS-inducing therapies. DSF, through redox modulation, may be a useful approach to enhance chemo- and/or radio-sensitivity for advanced BC subtypes where therapeutic resistance is an impediment to durable responses to current standard of care.

Genomic profiling of inflammatory breast cancer: a review

Inflammatory breast cancer (IBC) is a rare but aggressive form of breast cancer. Despite efforts in the past decade to delineate the molecular biology of IBC by applying high-throughput molecular profiling technologies to clinical samples, IBC remains insufficiently characterized. The reasons for that include limited sizes of the study population, heterogeneity with respect to the composition of the IBC and non-IBC control groups and technological differences across studies. In 2008, the World IBC Consortium was founded to foster collaboration between research groups focusing on IBC. One of the initial projects was to redefine the molecular profile of IBC using an unprecedented number of samples and search for gene signatures associated with survival and response to neo-adjuvant chemotherapy. Here, we provide an overview of all the molecular profiling studies that have been performed on IBC clinical samples to date.

A meta analysis of pancreatic microarray datasets yields new targets as cancer genes and biomarkers

The lack of specific symptoms at early tumor stages, together with a high biological aggressiveness of the tumor contribute to the high mortality rate for pancreatic cancer (PC), which has a five year survival rate of less than 5%. Improved screening for earlier diagnosis, through the detection of diagnostic and prognostic biomarkers provides the best hope of increasing the rate of curatively resectable carcinomas. Though many serum markers have been reported to be elevated in patients with PC, so far, most of these markers have not been implemented into clinical routine due to low sensitivity or specificity. In this study, we have identified genes that are significantly upregulated in PC, through a meta-analysis of large number of microarray datasets. We demonstrate that the biological functions ascribed to these genes are clearly associated with PC and metastasis, and that that these genes exhibit a strong link to pathways involved with inflammation and the immune response. This investigation has yielded new targets for cancer genes, and potential biomarkers for pancreatic cancer. The candidate list of cancer genes includes protein kinase genes, new members of gene families currently associated with PC, as well as genes not previously linked to PC. In this study, we are also able to move towards developing a signature for hypomethylated genes, which could be useful for early detection of PC. We also show that the significantly upregulated 800+ genes in our analysis can serve as an enriched pool for tissue and serum protein biomarkers in pancreatic cancer.

Mn porphyrin in combination with ascorbate acts as a pro-oxidant and mediates caspase-independent cancer cell death

Resistance to therapy-mediated apoptosis in inflammatory breast cancer, an aggressive and distinct subtype of breast cancer, was recently attributed to increased superoxide dismutase (SOD) expression, glutathione (GSH) content, and decreased accumulation of reactive species. In this study, we demonstrate the unique ability of two Mn(III) N-substituted pyridylporphyrin (MnP)-based SOD mimics (MnTE-2-PyP(5+) and MnTnBuOE-2-PyP(5+)) to catalyze oxidation of ascorbate, leading to the production of excessive levels of peroxide, and in turn cell death. The accumulation of peroxide, as a consequence of MnP+ascorbate treatment, was fully reversed by the administration of exogenous catalase, showing that hydrogen peroxide is essential for cell death. Cell death as a consequence of the action of MnP+ascorbate corresponded to decreases in GSH levels, prosurvival signaling (p-NF-κB, p-ERK1/2), and in expression of X-linked inhibitor of apoptosis protein, the most potent caspase inhibitor. Although markers of classical apoptosis were observed, including PARP cleavage and annexin V staining, administration of a pan-caspase inhibitor, Q-VD-OPh, did not reverse the observed cytotoxicity. MnP+ascorbate-treated cells showed nuclear translocation of apoptosis-inducing factor, suggesting the possibility of a mechanism of caspase-independent cell death. Pharmacological ascorbate has already shown promise in recently completed phase I clinical trials, in which its oxidation and subsequent peroxide formation was catalyzed by endogenous metalloproteins. The catalysis of ascorbate oxidation by an optimized metal-based catalyst (such as MnP) carries a large therapeutic potential as an anticancer agent by itself or in combination with other modalities such as radio- and chemotherapy.

A core invasiveness gene signature reflects epithelial-to-mesenchymal transition but not metastatic potential in breast cancer cell lines and tissue samples

Introduction

Metastases remain the primary cause of cancer-related death. The acquisition of invasive tumour cell behaviour is thought to be a cornerstone of the metastatic cascade. Therefore, gene signatures related to invasiveness could aid in stratifying patients according to their prognostic profile. In the present study we aimed at identifying an invasiveness gene signature and investigated its biological relevance in breast cancer.

Methods & Results

We collected a set of published gene signatures related to cell motility and invasion. Using this collection, we identified 16 genes that were represented at a higher frequency than observed by coincidence, hereafter named the core invasiveness gene signature. Principal component analysis showed that these overrepresented genes were able to segregate invasive and non-invasive breast cancer cell lines, outperforming sets of 16 randomly selected genes (all P<0.001). When applied onto additional data sets, the expression of the core invasiveness gene signature was significantly elevated in cell lines forced to undergo epithelial-mesenchymal transition. The link between core invasiveness gene expression and epithelial-mesenchymal transition was also confirmed in a dataset consisting of 2420 human breast cancer samples. Univariate and multivariate Cox regression analysis demonstrated that CIG expression is not associated with a shorter distant metastasis free survival interval (HR = 0.956, 95%C.I. = 0.896–1.019, P = 0.186).

Discussion

These data demonstrate that we have identified a set of core invasiveness genes, the expression of which is associated with epithelial-mesenchymal transition in breast cancer cell lines and in human tissue samples. Despite the connection between epithelial-mesenchymal transition and invasive tumour cell behaviour, we were unable to demonstrate a link between the core invasiveness gene signature and enhanced metastatic potential.

Contribution of ER and NF-κB to endocrine resistance in inflammatory breast cancer

SUMMARY Inflammatory breast cancer (IBC) is a very aggressive form of breast cancer with a high mortality rate. Most patients have lymph node metastasis at the time of diagnosis and 30% of patients already have metastases in distant organs. IBC is normally treated with multimodality therapy. Endocrine therapy is administered in cases of ER-positive tumors. Nevertheless, IBC has a high HOXB13:Il17RB ratio, predicting a poor response to tamoxifen treatment. These data suggest a possible role for IBC as a model for endocrine resistance. Previous studies have shown that NF-κB, a transcription factor regulating different cellular processes, is more highly activated in IBC than in non-IBC, while ER is often downregulated in this tumor type. This article summarizes the activity of ER and NF-κB in IBC and their possible contribution to endocrine resistance in this breast cancer subtype.

Comparison of molecular subtype distribution in triple-negative inflammatory and non-inflammatory breast cancers

Introduction

Because of its high rate of metastasis, inflammatory breast cancer (IBC) has a poor prognosis compared with non-inflammatory types of breast cancer (non-IBC). In a recent study, Lehmann and colleagues identified seven subtypes of triple-negative breast cancer (TNBC). We hypothesized that the distribution of TNBC subtypes differs between TN-IBC and TN-non-IBC. We determined the subtypes and compared clinical outcomes by subtype in TN-IBC and TN-non-IBC patients.

Methods

We determined TNBC subtypes in a TNBC cohort from the World IBC Consortium for which IBC status was known (39 cases of TN-IBC; 49 cases of TN-non-IBC). We then determined the associations between TNBC subtypes and IBC status and compared clinical outcomes between TNBC subtypes.

Results

We found the seven subtypes exist in both TN-IBC and TN-non-IBC. We found no association between TNBC subtype and IBC status (P = 0.47). TNBC subtype did not predict recurrence-free survival. IBC status was not a significant predictor of recurrence-free or overall survival in the TNBC cohort.

Conclusions

Our data show that, like TN-non-IBC, TN-IBC is a heterogeneous disease. Although clinical characteristics differ significantly between IBC and non-IBC, no unique IBC-specific TNBC subtypes were identified by mRNA gene-expression profiles of the tumor. Studies are needed to identify the subtle molecular or microenvironmental differences that contribute to the differing clinical behaviors between TN-IBC and TN-non-IBC.

Uncovering the molecular secrets of inflammatory breast cancer biology: an integrated analysis of three distinct affymetrix gene expression datasets

BACKGROUND

Inflammatory breast cancer (IBC) is a poorly characterized form of breast cancer. So far, the results of expression profiling in IBC are inconclusive due to various reasons including limited sample size. Here, we present the integration of three Affymetrix expression datasets collected through the World IBC Consortium allowing us to interrogate the molecular profile of IBC using the largest series of IBC samples ever reported.

EXPERIMENTAL DESIGN

Affymetrix profiles (HGU133-series) from 137 patients with IBC and 252 patients with non-IBC (nIBC) were analyzed using unsupervised and supervised techniques. Samples were classified according to the molecular subtypes using the PAM50-algorithm. Regression models were used to delineate IBC-specific and molecular subtype-independent changes in gene expression, pathway, and transcription factor activation.

RESULTS

Four robust IBC-sample clusters were identified, associated with the different molecular subtypes (P<0.001), all of which were identified in IBC with a similar prevalence as in nIBC, except for the luminal A subtype (19% vs. 42%; P<0.001) and the HER2-enriched subtype (22% vs. 9%; P<0.001). Supervised analysis identified and validated an IBC-specific, molecular subtype-independent 79-gene signature, which held independent prognostic value in a series of 871 nIBCs. Functional analysis revealed attenuated TGF-β signaling in IBC.

CONCLUSION

We show that IBC is transcriptionally heterogeneous and that all molecular subtypes described in nIBC are detectable in IBC, albeit with a different frequency. The molecular profile of IBC, bearing molecular traits of aggressive breast tumor biology, shows attenuation of TGF-β signaling, potentially explaining the metastatic potential of IBC tumor cells in an unexpected manner.

Expression of ALDH1 in breast invasive ductal carcinoma: an independent predictor of early tumor relapse

Background

The specific mechanism underlying the contribution of the Aldehyde dehydrogenase 1 (ALDH1) phenotype to metastatic behavior and early tumor relapse in breast cancer is currently unclear.

Methods

147 randomly selected invasive ductal carcinoma samples were assayed for expression of ALDH1A1, NOTCH1, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2), and association of the ALDH1A1 phenotype with clinic pathological features was further evaluated.

Results

ALDH1A1-positive cells were detected in 63.3% (93 of 147) of tumors. 80.0% (32 of 40) of tumors with strong ALDH1A1 staining displayed early recurrence, compared with 20.0% (8 of 40) of tumors negative for ALDH1A1 expression (P = 0.027). ALDH1A1 status was significantly correlated with strong malignant proliferative marker Ki67 staining (P = 0.001), and no significantly different expression of ALDH1A1 across the subtypes of ER, PR, and HER2 expression and triple negative features of tumor tissue. Multivariate regression analysis demonstrated that elevated ALDH1A1 expression is an independent predictor of recurrence-free survival and distant metastasis-free survival. Notably, breast cancer tissue strong for ALDH1A1 expression displayed weak NOTCH1 staining compared to ALDH1A1 weak tumor tissue (P = 0.002), and the relationship between ALDH1A1 and NOTCH1 mRNA positivity was significant (Pearson correlation - 0.337, P = 0.014; Spearman’s rho - 0.376, P = 0.006). Elevated NOTCH1 mRNA level (using a cut-off value based on the median ALDH1A1 2^-△△CT value) was associated with reduction of ALDH1A1 mRNA level (P = 0.001).

Conclusions

The ALDH1A1 phenotype is an independent predictor of early tumor relapse characteristic (specifically, incidence of early local recurrence and distant metastasis) of invasive ductal carcinoma. The NOTCH1 signaling pathway is possibly involved in the negative association of the ALDH1A1 phenotype with early malignant relapse in invasive ductal carcinoma.

Role of nuclear factor-ĸB in breast and colorectal cancer

The purpose of this review article is to highlight articles and new research regarding the link between NF-ĸB and several cancers. This review presents the most up-to-date NF-ĸB research and how it links this important transcription factor with hematology and oncology. It was written by conducting a thorough search of Pubmed as well as several journals such as Cancer, Nature, Science, Cell and those of one of the authors. The articles relating to the link between NF-ĸB and cancer were used to write this review. The results of this study clarified that there is a critical link between NF-ĸB and cancer. NF-ĸB has often been implicated in a variety of different diseases and it plays a variety of roles in cell survival, differentiation, and proliferation of cells. In cancer, NF-ĸB plays a pivotal role by facilitating oncogenesis as well as metastasis. A thorough understanding of NF-ĸB and its role in cancer can lead to future studies and drug development which could provide a novel option in the treatment of this disease.

Genomic and expression analysis of microdissected inflammatory breast cancer

Inflammatory breast cancer (IBC) is a unique clinical entity characterized by rapid onset of erythema and swelling of the breast often without an obvious breast mass. Many studies have examined and compared gene expression between IBC and non-IBC (nIBC), repeatedly finding clusters associated with receptor subtype, but no consistent gene signature associated with IBC has been validated. Here we compared microdissected IBC tumor cells to microdissected nIBC tumor cells matched based on estrogen and HER-2/neu receptor status. Gene expression analysis and comparative genomic hybridization were performed. An IBC gene set and genomic set were identified using a training set and validated on the remaining data. The IBC gene set was further tested using data from IBC consortium samples and publicly available data. Receptor driven clusters were identified in IBC; however, no IBC-specific gene signature was identified. Fifteen genes were correlated between increased genomic copy number and gene overexpression data. An expression-guided gene set upregulated in the IBC training set clustered the validation set into two clusters independent of receptor subtype but segregated only 75 % of samples in each group into IBC or nIBC. In a larger consortium cohort and in published data, the gene set failed to optimally enrich for IBC samples. However, this gene set had a high negative predictive value for excluding the diagnosis of IBC in publicly available data (100 %). An IBC enriched genomic data set accurately identified 10/16 cases in the validation data set. Even with microdissection, no IBC-specific gene signature distinguishes IBC from nIBC. Using microdissected data, a validated gene set was identified that is associated with IBC tumor cells. Inflammatory breast cancer comparative genomic hybridization data are presented, but a validated genomic data set that identifies IBC is not demonstrated.

Human cytomegalovirus infection enhances NF-κB/p65 signaling in inflammatory breast cancer patients

Human Cytomegalovirus (HCMV) is an endemic herpes virus that re-emerges in cancer patients enhancing oncogenic potential. Recent studies have shown that HCMV infection is associated with certain types of cancer morbidity such as glioblastoma. Although HCMV has been detected in breast cancer tissues, its role, if any, in the etiology of specific forms of breast cancer has not been investigated. In the present study we investigated the presence of HCMV infection in inflammatory breast cancer (IBC), a rapidly progressing form of breast cancer characterized by specific molecular signature. We screened for anti-CMV IgG antibodies in peripheral blood of 49 non-IBC invasive ductal carcinoma (IDC) and 28 IBC patients. In addition, we screened for HCMV-DNA in postsurgical cancer and non-cancer breast tissues of non-IBC and IBC patients. We also tested whether HCMV infection can modulate the expression and activation of transcriptional factor NF-κB/p65, a hallmark of IBC. Our results reveal that IBC patients are characterized by a statistically significant increase in HCMV IgG antibody titers compared to non-IBC patients. HCMV-DNA was significantly detected in cancer tissues than in the adjacent non-carcinoma tissues of IBC and IDC, and IBC cancer tissues were significantly more infected with HCMV-DNA compared to IDC. Further, HCMV sequence analysis detected different HCMV strains in IBC patients tissues, but not in the IDC specimens. Moreover, HCMV-infected IBC cancer tissues were found to be enhanced in NF-κB/p65 signaling compared to non-IBC patients. The present results demonstrated a correlation between HCMV infection and IBC. Etiology and causality of HCMV infection with IBC now needs to be rigorously examined.

The interaction between ER and NFκB in resistance to endocrine therapy

Endocrine therapy is a commonly used treatment for estrogen receptor (ER)-positive breast cancer. Although endocrine therapy has a favorable outcome in many patients, development of resistance is common. Recent studies have shown that NFκB, a transcription factor regulating a wide variety of cellular processes, might play a role in the development of endocrine resistance. The precise interaction between ER and NFκB and how this contributes to the attenuated responsiveness of ER-positive breast cancer cells to hormonal treatment remains unclear. This review provides an overview of the mechanisms of action for both transcription factors and focuses on the current knowledge explaining how ER and NFκB affect each other's activity and how this cross-talk might contribute to the development of an endocrine resistance phenotype in breast cancer cells.

Pre-clinical studies of Notch signaling inhibitor RO4929097 in inflammatory breast cancer cells

Basal breast cancer, common among patients presenting with inflammatory breast cancer (IBC), has been shown to be resistant to radiation and enriched in cancer stem cells. The Notch pathway plays an important role in self-renewal of breast cancer stem cells and contributes to inflammatory signaling which promotes the breast cancer stem cell phenotype. Herein, we inhibited Notch signaling using a gamma secretase inhibitor, RO4929097, in an in vitro model that enriches for cancer initiating cells (3D clonogenic assay) and conventional 2D clonogenic assay to compare the effect on radiosensitization of the SUM149 and SUM190 IBC cell lines. RO4929097 downregulated the Notch target genes Hes1, Hey1, and HeyL, and showed a significant reduction in anchorage independent growth in SUM190 and SUM149. However, the putative self-renewal assay mammosphere formation efficiency was increased with the drug. To assess radiosensitization of putative cancer stem cells, cells were exposed to increasing doses of radiation with or without 1 μM RO4929097 in their standard (2D) and self-renewal enriching (3D) culture conditions. In the conventional 2D clonogenic assay, RO4929097 significantly sensitized SUM190 cells to ionizing radiation and has a modest radiosensitization effect in SUM149 cells. In the 3D clonogenic assays, however, a radioprotective effect was seen in both SUM149 and SUM190 cells at higher doses. Both cell lines express IL-6 and IL-8 cytokines known to mediate the efficacy of Notch inhibition and to promote self-renewal of stem cells. We further showed that RO429097 inhibits normal T-cell synthesis of some inflammatory cytokines, including TNF-α, a potential mediator of IL-6 and IL-8 production in the microenvironment. These data suggest that additional targeting agents may be required to selectively target IBC stem cells through Notch inhibition, and that evaluation of microenvironmental influences may shed further light on the potential effects of this inhibitor.

Glycogen synthase kinase-3β, NF-κB signaling, and tumorigenesis of human osteosarcoma

Background

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, may function as a tumor suppressor or an oncogene, depending on the tumor type. We sought to determine the biological function of GSK-3β in osteosarcoma, a rare pediatric cancer for which the identification of new therapeutic targets is urgent.

Methods

We used cell viability assays, colony formation assays, and apoptosis assays to analyze the effects of altered GSK-3β expression in U2OS, MG63, SAOS2, U2OS/MTX300, and ZOS osteosarcoma cell lines. Nude mice (n = 5–8 mice per group) were injected with U2OS/MTX300, and ZOS cells to assess the role of GSK-3β in osteosarcoma growth in vivo and to evaluate the effects of inhibitors and/or anticancer drugs on tumor growth. We used an antibody array, polymerase chain reaction, western blotting, and a luciferase reporter assay to establish the effect of GSK-3β inhibition on the nuclear factor-κB (NF-κB) pathway. Immunochemistry was performed on primary tumor specimens from osteosarcoma patients (n = 74) to determine the relationship of GSK-3β activity with overall survival.

Results

Osteosarcoma cells with low levels of inactive p-Ser9-GSK-3β formed colonies in vitro and tumors in vivo more readily than cells with higher levels and cells in which GSK-3β had been silenced formed fewer colonies and smaller tumors than parental cells. Silencing or pharmacological inhibition of GSK-3β resulted in apoptosis of osteosarcoma cells. Inhibition of GSK-3β resulted in inhibition of the NF-κB pathway and reduction of NF-κB-mediated transcription. Combination treatments with GSK-3β inhibitors, NF-κB inhibitors, and chemotherapy drugs increased the effectiveness of chemotherapy drugs in vitro and in vivo. Patients whose osteosarcoma specimens had hyperactive GSK-3β, and nuclear NF-κB had a shorter median overall survival time (49.2 months) compared with patients whose tumors had inactive GSK-3β and NF-κB (109.2 months).

Conclusion

GSK-3β activity may promote osteosarcoma tumor growth, and therapeutic targeting of the GSK-3β and/or NF-κB pathways may be an effective way to enhance the therapeutic activity of anticancer drugs against osteosarcoma.

Core module biomarker identification with network exploration for breast cancer metastasis

BACKGROUND

In a complex disease, the expression of many genes can be significantly altered, leading to the appearance of a differentially expressed "disease module". Some of these genes directly correspond to the disease phenotype, (i.e. "driver" genes), while others represent closely-related first-degree neighbours in gene interaction space. The remaining genes consist of further removed "passenger" genes, which are often not directly related to the original cause of the disease. For prognostic and diagnostic purposes, it is crucial to be able to separate the group of "driver" genes and their first-degree neighbours, (i.e. "core module") from the general "disease module".

RESULTS

We have developed COMBINER: COre Module Biomarker Identification with Network ExploRation. COMBINER is a novel pathway-based approach for selecting highly reproducible discriminative biomarkers. We applied COMBINER to three benchmark breast cancer datasets for identifying prognostic biomarkers. COMBINER-derived biomarkers exhibited 10-fold higher reproducibility than other methods, with up to 30-fold greater enrichment for known cancer-related genes, and 4-fold enrichment for known breast cancer susceptible genes. More than 50% and 40% of the resulting biomarkers were cancer and breast cancer specific, respectively. The identified modules were overlaid onto a map of intracellular pathways that comprehensively highlighted the hallmarks of cancer. Furthermore, we constructed a global regulatory network intertwining several functional clusters and uncovered 13 confident "driver" genes of breast cancer metastasis.

CONCLUSIONS

COMBINER can efficiently and robustly identify disease core module genes and construct their associated regulatory network. In the same way, it is potentially applicable in the characterization of any disease that can be probed with microarrays.

Context-specific regulation of NF-κB target gene expression by EZH2 in breast cancers

Both EZH2 and NF-κB contribute to aggressive breast cancer, yet whether the two oncogenic factors have functional crosstalk in breast cancer is unknown. Here, we uncover an unexpected role of EZH2 in conferring the constitutive activation of NF-κB target gene expression in ER-negative basal-like breast cancer cells. This function of EZH2 is independent of its histone methyltransferase activity but requires the physical interaction with RelA/RelB to promote the expression of NF-κB targets. Intriguingly, EZH2 acts oppositely in ER-positive luminal-like breast cancer cells and represses NF-κB target gene expression by interacting with ER and directing repressive histone methylation on their promoters. Thus, EZH2 functions as a double-facet molecule in breast cancers, either as a transcriptional activator or repressor of NF-κB targets, depending on the cellular context. These findings reveal an additional mechanism by which EZH2 promotes breast cancer progression and underscore the need for developing context-specific strategy for therapeutic targeting of EZH2 in breast cancers.

Computational simulations to predict creatine kinase-associated factors: protein-protein interaction studies of brain and muscle types of creatine kinases

Creatine kinase (CK; EC 2.7.3.2) is related to several skin diseases such as psoriasis and dermatomyositis. CK is important in skin energy homeostasis because it catalyzes the reversible transfer of a phosphoryl group from MgATP to creatine. In this study, we predicted CK binding proteins via the use of bioinformatic tools such as protein-protein interaction (PPI) mappings and suggest the putative hub proteins for CK interactions. We obtained 123 proteins for brain type CK and 85 proteins for muscle type CK in the interaction networks. Among them, several hub proteins such as NFKB1, FHL2, MYOC, and ASB9 were predicted. Determination of the binding factors of CK can further promote our understanding of the roles of CK in physiological conditions.