Relationship of sialyl-Lewis(x/a) underexpression and E-cadherin overexpression in the lymphovascular embolus of inflammatory breast carcinoma

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.

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.

Inflammatory breast cancer defined: proposed common diagnostic criteria to guide treatment and research

Purpose

Inflammatory breast cancer is a deadly and aggressive type of breast cancer. A key challenge relates to the need for a more detailed, formal, objective definition of IBC, the lack of which compromises clinical care, hampers the conduct of clinical trials, and hinders the search for IBC-specific biomarkers and treatments because of the heterogeneity of patients considered to have IBC.

Methods

Susan G. Komen, the Inflammatory Breast Cancer Research Foundation, and the Milburn Foundation convened patient advocates, clinicians, and researchers to review the state of IBC and to propose initiatives to advance the field. After literature review of the defining clinical, pathologic, and imaging characteristics of IBC, the experts developed a novel quantitative scoring system for diagnosis.

Results

The experts identified through consensus several “defining characteristics” of IBC, including factors related to timing of onset and specific symptoms. These reflect common pathophysiologic changes, sometimes detectable on biopsy in the form of dermal lymphovascular tumor emboli and often reflected in imaging findings. Based on the importance and extent of these characteristics, the experts developed a scoring scale that yields a continuous score from 0 to 48 and proposed cut-points for categorization that can be tested in subsequent validation studies.

Conclusion

To move beyond subjective ‘clinical diagnosis’ of IBC, we propose a quantitative scoring system to define IBC, based on clinical, pathologic, and imaging features. This system is intended to predict outcome and biology, guide treatment decisions and inclusion in clinical trials, and increase diagnostic accuracy to aid basic research; future validation studies are necessary to evaluate its performance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06434-x.

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.

Comparison of molecular profile in triple-negative inflammatory and non-inflammatory breast cancer not of mesenchymal stem-like subtype

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive form of breast cancer. The triple-negative subtype of IBC (TN-IBC) is particularly aggressive. Identification of molecular differences between TN-IBC and TN-non-IBC may help clarify the unique clinical behaviors of TN-IBC. However, our previous study comparing gene expression between TN-IBC and TN-non-IBC did not identify any TN-IBC-specific molecular signature. Lehmann et al recently reported that the mesenchymal stem-like (MSL) TNBC subtype consisted of infiltrating tumor-associated stromal cells but not cancer cells. Therefore, we compared the gene expression profiles between TN-IBC and TN-non-IBC patient samples not of the MSL subtype.

METHODS

We classified 88 TNBC samples from the World IBC Consortium into subtypes according to the Vanderbilt classification and Insight TNBCtype, removed samples of MSL and unstable subtype, and compared gene expression profiles between the remaining TN-IBC and TN-non-IBC samples.

RESULTS

In the Vanderbilt analysis, we identified 75 genes significantly differentially expressed between TN-IBC and TN-non-IBC at an FDR of 0.2. In the Insight TNBCtype analysis, we identified 81 genes significantly differentially expressed between TN-IBC and TN-non-IBC at an FDR of 0.4. In both analyses, the top canonical pathway was "Fc Receptor-mediated Phagocytosis in Macrophages and Monocytes", and the top 10 differentially regulated genes included PADI3 and MCTP1, which were up-regulated, and CDC42EP3, SSR1, RSBN1, and ZC3H13, which were downregulated.

CONCLUSIONS

Our data suggest that the activity of macrophages might be enhanced in TN-IBC compared with TN-non-IBC. Further clinical and preclinical studies are needed to determine the cross-talk between macrophages and IBC cells.

P-Glycoprotein and Breast Cancer Resistance Protein in Canine Inflammatory and Noninflammatory Grade III Mammary Carcinomas

P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) expression are frequently related to multidrug resistance (MDR) in neoplastic cells. Canine inflammatory and grade III noninflammatory mammary carcinomas (IMC and non-IMC) are aggressive tumors that could benefit from chemotherapy. This study describes the immunohistochemical detection of P-gp and BCRP in 20 IMCs and 18 non-IMCs from dogs that had not received chemotherapy. Our aim was to determine if P-gp and BCRP expression was related to the "inflammatory" phenotype, to establish a basis for future studies analyzing the response to chemotherapy in dogs with highly malignant mammary cancer. Immunolabeling was primarily membranous for P-gp with a more intense labeling in emboli, and immunolabeling was membranous and cytoplasmic for BCRP. P-gp was expressed in 17 of 20 (85%) IMCs compared to 7 of 18 (39%) non-IMCs (P = 0.006). BCRP was expressed within emboli in 15 of 19 (79%) emboli in IMC, 12 of 15 (80%) primary IMCs, and 12 of 18 (67%) non-IMCs, without statistically significant differences (P > .05). All IMCs and 67% of non-IMCs expressed at least 1 of the 2 transporters, and 63% (12/19) of IMCs and 39% (7/18) of non-IMCs expressed both P-gp and BCRP. P-gp and BCRP evaluation might help select patients for chemotherapy. P-gp, expressed in a significantly higher percentage of IMCs vs non-IMCs, might play a specific role in the chemoresistance of IMC.

High Expression of Plakoglobin Promotes Metastasis in Invasive Micropapillary Carcinoma of the Breast via Tumor Cluster Formation

Invasive micropapillary carcinoma of the breast (IMPC) is a rare subtype of breast cancer that has a high frequency of lymph node (LN) involvement and metastasis to distant organs. IMPC is characterized by distinct histomorphology and unfavorable prognosis when compared with invasive ductal carcinoma no special type (IDC-NST). However, the underlying molecular mechanisms remain unclear. We reported here that plakoglobin, as a key component in cell adhesion, can promote collective metastasis through facilitating IMPC clusters formation. In comparing the clinicopathological features of 451 IMPC patients and 282 IDC-NST patients, our results showed that tumor emboli were significantly higher in IMPC patients and were associated with a high frequency of metastasis. Both in vitro and in vivo data showed overexpression of plakoglobin in both the cell membrane and the cytoplasm of IMPC clusters. When plakoglobin was knocked down in IMPC cell models, the tumor cell clusters were depolymerized. Using mouse models, we validated the metastatic potential of tumor clusters was higher than single cells in vivo. Further analysis showed that higher expression of plakoglobin was able to promote activation of the PI3K/Akt/Bcl-2 pathway, which might protect the clusters from anoikis. Our data indicate that plakoglobin promotes tumor cluster formation in IMPC and downregulates apoptosis in the cell clusters through activation of PI3K/Akt/Bcl-2 signaling. These results provide a convincing rationale for the high metastatic propensity seen in IMPC.

Elevated serum levels of sialyl Lewis X (sLeX) and inflammatory mediators in patients with breast cancer

PURPOSE

The carbohydrate sialyl Lewis^X (sLe^X) mediates cell adhesion, is critical in the normal function of immune cells, and is frequently over-expressed on cancer cells. We assessed the association, differential levels, and prognostic value of sLe^X and inflammatory cytokines/chemokines in breast cancer sera.

METHODS

We retrospectively measured sLe^X and a panel of cytokines/chemokines in the sera of 26 non-invasive ductal carcinoma in situ (DCIS), 154 invasive non-metastatic breast cancer (non-MBC), 63 metastatic breast cancer (MBC) patients, and 43 healthy controls. Differences in sLe^X and inflammatory cytokines among and between patient groups and healthy controls were assessed with nonparametric tests and we performed survival analysis for the prognostic potential of sLe^X using a cut-off of 8 U/mL as previously defined.

RESULTS

Median serum sLe^X was significantly higher than controls for invasive breast cancer patients (MBC and non-MBC) but not DCIS. In univariate analysis, we confirmed patients with serum sLe^X > 8 U/mL have a significantly shorter progression-free survival (PFS) (P = 0.0074) and overall survival (OS (P = 0.0003). Similarly, patients with high serum MCP-1 and IP-10 had shorter OS (P = 0.001 and P < 0.001, respectively) and PFS (P = 0.010 and P < 0.001, respectively). sLe^X, MCP-1 and IP-10 remained significant in multivariate survival analysis.

CONCLUSION

Elevated serum sLe^X was associated with invasive cancer but not DCIS. High serum sLe^X levels were associated with inflammatory mediators and may play a role in facilitating local invasion of breast tumor. Furthermore, serum MCP-1, IP-10 and sLe^X may have prognostic value in breast cancer.

Beyond cell-cell adhesion: Plakoglobin and the regulation of tumorigenesis and metastasis

Plakoglobin (also known as? -catenin) is a member of the Armadillo family of proteins and a paralog of β -catenin. Plakoglobin is a component of both the adherens junctions and desmosomes, and therefore plays a vital role in the regulation of cell-cell adhesion. Similar to β -catenin, plakoglobin is capable of participating in cell signaling in addition to its role in cell-cell adhesion. In this context, β -catenin has a well-documented oncogenic potential as a component of the Wnt signaling pathway. In contrast, while some studies have suggested a tumor promoting activity of plakoglobin in a cell/malignancy specific context, it generally acts as a tumor/metastasis suppressor. How plakoglobin acts as a growth/metastasis inhibitory protein has remained, until recently, unclear. Recent evidence suggests that plakoglobin may suppress tumorigenesis and metastasis by multiple mechanisms, including the suppression of oncogenic signaling, interactions with various proteins involved in tumorigenesis and metastasis, and the regulation of the expression of genes involved in these processes. This review is primarily focused on various mechanisms by which plakoglobin may inhibit tumorigenesis and metastasis.

Comparative aspects of canine and human inflammatory breast cancer

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

EGFR signaling promotes inflammation and cancer stem-like activity in inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most lethal and aggressive type of breast cancer, with a strong proclivity to metastasize, and IBC-specific targeted therapies have not yet been developed. Epidermal growth factor receptor (EGFR) has emerged as an important therapeutic target in IBC. However, the mechanism behind the therapeutic effect of EGFR targeted therapy is not well defined. Here, we report that EGFR regulates the IBC cell population that expresses cancer stem-like cell (CSC) markers through COX-2, a key mediator of inflammation whose expression correlates with worse outcome in IBC. The COX-2 pathway promoted IBC cell migration and invasion and the CSC marker-bearing population in vitro, and the inhibition of this pathway reduced IBC tumor growth in vivo. Mechanistically, we identified Nodal, a member of the TGFβ superfamily, as a potential driver of COX-2-regulated invasive capacity and the CSC phenotype of IBC cells. Our data indicate that the EGFR pathway regulates the expression of COX-2, which in turn regulates the expression of Nodal and the activation of Nodal signaling. Together, our findings demonstrate a novel connection between the EGFR/COX-2/Nodal signaling axis and CSC regulation in IBC, which has potential implications for new combination approaches with EGFR targeted therapy for patients with IBC.

Spontaneously-forming spheroids as an in vitro cancer cell model for anticancer drug screening

The limited translational value in clinic of analyses performed on 2-D cell cultures has prompted a shift toward the generation of 3-dimensional (3-D) multicellular systems. Here we present a spontaneously-forming in vitro cancer spheroid model, referred to as spheroids^MARY-X, that precisely reflects the pathophysiological features commonly found in tumor tissues and the lymphovascular embolus. In addition, we have developed a rapid, inexpensive means to evaluate response following drug treatment where spheroid dissolution indices from brightfield image analyses are used to construct dose-response curves resulting in relevant IC₅₀ values. Using the spheroids^MARY-X model, we demonstrate the unique ability of a new class of molecules, containing the caged Garcinia xanthone (CGX) motif, to induce spheroidal dissolution and apoptosis at IC₅₀ values of 0.42 +/−0.02 μM for gambogic acid and 0.66 +/−0.02 μM for MAD28. On the other hand, treatment of spheroids^MARY-X with various currently approved chemotherapeutics of solid and blood-borne cancer types failed to induce any response as indicated by high dissolution indices and subsequent poor IC₅₀ values, such as 7.8 +/−3.1 μM for paclitaxel. Our studies highlight the significance of the spheroids^MARY-X model in drug screening and underscore the potential of the CGX motif as a promising anticancer pharmacophore.

Methods for Tumor Targeting with Salmonella typhimurium A1-R

Salmonella typhimurium A1-R (S. typhimurium A1-R) has shown great preclinical promise as a broad-based anti-cancer therapeutic (please see Chapter 1 ). The present chapter describes materials and methods for the preclinical study of S. typhimurium A1-R in clinically-relevant mouse models. Establishment of orthotopic metastatic mouse models of the major cancer types is described, as well as other useful models, for efficacy studies of S. typhimurium A1-R or other tumor-targeting bacteria, as well. Imaging methods are described to visualize GFP-labeled S. typhimurium A1-R, as well as GFP- and/or RFP-labeled cancer cells in vitro and in vivo, which S. typhimurium A1-R targets. The mouse models include metastasis to major organs that are life-threatening to cancer patients including the liver, lung, bone, and brain and how to target these metastases with S. typhimurium A1-R. Various routes of administration of S. typhimurium A1-R are described with the advantages and disadvantages of each. Basic experiments to determine toxic effects of S. typhimurium A1-R are also described. Also described are methodologies for combining S. typhimurium A1-R and chemotherapy. The testing of S. typhimurium A1-R on patient tumors in patient-derived orthotopic xenograft (PDOX) mouse models is also described. The major methodologies described in this chapter should be translatable for clinical studies.

Synthesis and cell-selective antitumor properties of amino acid conjugated tumor-associated carbohydrate antigen-coated gold nanoparticles

The Thomsen Friedenreich antigen (TFag) disaccharide is a tumor-associated carbohydrate antigen (TACA) found primarily on carcinoma cells and rarely expressed in normal tissue. The TFag has been shown to interact with Galectin-3 (Gal-3), one in a family of β-galactoside binding proteins. Galectins have a variety of cellular functions, and Gal-3 has been shown to be the sole galectin with anti-apoptotic activity. We have previously prepared gold nanoparticles (AuNP) coated with the TFag in various presentations as potential anti-adhesive therapeutic tools or antitumor vaccine platforms. Here we describe the synthesis of TFag-glycoamino acid conjugates attached to gold nanoparticles through a combined alkane/PEG linker, where the TFag was attached to either a serine or threonine amino acid. Particles were fully characterized by a host of biophysical techniques, and along with a control particle carrying hydroxyl-terminated linker units, were evaluated in both Gal-3 positive and negative cell lines. We show that the particles bearing the saccharides selectively inhibited tumor cell growth of the Gal-3 positive cells significantly more than the Gal-3 negative cells. In addition, the threonine-attached TF particles were more potent than the serine-attached constructs. These results support the use of AuNP as antitumor therapeutic platforms, targeted against cell lines that express specific lectins that interact with TFag.

Back to the Future: Are Tumor-Targeting Bacteria the Next-Generation Cancer Therapy?

Cancer patients infected with various bacteria were reported, for at least two centuries, to have spontaneous remission. W.B. Coley, of what is now the Memorial Sloan-Kettering Cancer Center, pioneered bacterial therapy of cancer in the clinic with considerable success beginning in the late nineteenth century. After Coley died in 1936, bacterial therapy of cancer essentially ended. Currently there is much excitement in developing bacterial therapy for treating cancer using either obligate or facultative anaerobic bacteria. This chapter will demonstrate the potential and strategy of Salmonella typhimurium A1-R, an engineered tumor-targeting variant for the systemic treatment of metastatic cancer. A new concept using Salmonella typhimurium A1-R for cell cycle "decoy" chemotherapy of metastatic cancer is also described.

Ex vivo treatment response of primary tumors and/or associated metastases for preclinical and clinical development of therapeutics

The molecular analysis of established cancer cell lines has been the mainstay of cancer research for the past several decades. Cell culture provides both direct and rapid analysis of therapeutic sensitivity and resistance. However, recent evidence suggests that therapeutic response is not exclusive to the inherent molecular composition of cancer cells but rather is greatly influenced by the tumor cell microenvironment, a feature that cannot be recapitulated by traditional culturing methods. Even implementation of tumor xenografts, though providing a wealth of information on drug delivery/efficacy, cannot capture the tumor cell/microenvironment crosstalk (i.e., soluble factors) that occurs within human tumors and greatly impacts tumor response. To this extent, we have developed an ex vivo (fresh tissue sectioning) technique which allows for the direct assessment of treatment response for preclinical and clinical therapeutics development. This technique maintains tissue integrity and cellular architecture within the tumor cell/microenvironment context throughout treatment response providing a more precise means to assess drug efficacy.

TIG1 promotes the development and progression of inflammatory breast cancer through activation of Axl kinase

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer, but the basis for its aggressive properties are not fully understood. In this study, we report that high tumoral expression of TIG1 (RARRES1), a functionally undefined membrane protein, confers shorter survival in patients with IBC. TIG1 depletion decreased IBC cell proliferation, migration, and invasion in vitro and inhibited tumor growth of IBC cells in vivo. We identified the receptor tyrosine kinase, Axl, as a TIG1-binding protein. TIG1 interaction stablilized Axl by inhibiting its proteasome-dependent degradation. TIG1-depleted IBC cells exhibited reduced Axl expression, inactivation of NF-κB, and downregulation of matrix metalloproteinase-9, indicating that TIG1 regulates invasion of IBC cells by supporting the Axl signaling pathway in IBC cells. Consistent with these results, treatment of IBC cells with the Axl inhibitor SGI-7079 decreased their malignant properties in vitro. Finally, TIG1 expression correlated positively with Axl expression in primary human IBC specimens. Our findings establish that TIG1 positively modifies the malignant properties of IBC by supporting Axl function, advancing understanding of its development and rationalizing TIG1 and Axl as promising therapeutic targets in IBC treatment.

Modeling and characterization of inflammatory breast cancer emboli grown in vitro

Inflammatory breast cancer (IBC) is the deadliest form of breast cancer, presenting as intralymphatic emboli. Emboli within the dermal lymphatic vessels are thought to contribute to rapid metastasis. The lack of appropriate in vitro models has made it difficult to accurately study how IBC emboli metastasize. To date, attempts at creating IBC tumor emboli in vitro have used 3D culture on a solid layer of Matrigel(TM) , which does not resemble the physical properties of the lymphatic system. Dermal lymphatic fluid produces oscillatory fluid shear forces and is 1.5-1.7-fold more viscous than water with a pH range of 7.5-7.7. We have established a method for forming tumor emboli by culturing the IBC cell lines in suspension with either polyethylene glycol- or hyaluronic acid-containing medium and oscillatory fluid shear forces. Non-IBC cells do not form emboli under identical conditions. In vitro IBC emboli were analyzed for expression of markers associated with patient emboli and their ability to undergo invasion. In a direct comparison, the in vitro IBC emboli closely resemble IBC patient emboli with respect to size, composition and E-cadherin expression. Further, cells from the emboli are able to invade in clusters via RhoC GTPase-dependent amoeboid movement. Invasion by clusters of IBC cells is disrupted by exposure to TGFβ. This study provides a biologically relevant in vitro model to accurately grow and study inflammatory breast cancer biology and metastasis.

Transfection of miRNAs targeting the FUT3 gene inhibits cell proliferation in human gastric cancer cell line KATO-III

AIM: To investigate the effect of inhibition of FUT3 gene expression with miRNAs on the proliferation of gastric cancer cells (KATO-Ⅲ).

METHODS: Vectors carrying two miRNAs targeting the FUT3 gene were constructed and transiently transfected into KATO-III cells using lipidosome-mediated method. RT-PCR was performed to detect the expression of FUT3 mRNA, and immunocytochemistry and flow cytometry analysis were carried out to test expression variation of sLeA antigen. MTT assay and colony-forming assay were used to analyze cell proliferation and to detect the effect of decreased FUT3 expression on cell growth.

RESULTS: Compared to non-transfected cells and cells transfected with empty vector, the relative expression levels of FUT3 mRNA were significantly decreased (0.41 ± 0.01 vs 0.71 ± 0.05, 0.65 ± 0.03, both P < 0.05; 0.36 ± 0.02 vs 0.71 ± 0.05, 0.65 ± 0.03, both P < 0.05); the sLeA antigen expression levels were also significantly reduced (35.51% ± 0.36% vs 52.79% ± 2.62%, 49.75% ± 1.29%, both P < 0.05; 26.05% ± 1.14% vs 52.79% ± 2.62%, 49.75% ± 1.29%, both P < 0.05); cell growth was significantly inhibited (38.10% ± 1.96% vs 5.6% ± 0.63%, 8.9% ± 0.91%, both P < 0.05; 49.04% ± 2.37% vs 5.6% ± 0.63%, 8.9% ± 0.91%, both P < 0.05); and colony-forming ability was significantly reduced (14.10% ± 1.70% vs 29.79% ± 3.05%, 28.92% ± 2.10%, both P < 0.05; 12.50% ± 1.96% vs 29.79% ± 3.05%, 28.92% ± 2.10%, both P < 0.05) in FUT3-miRNA and FUT3-miRNA2 transfeced cells.

CONCLUSION: Transfection of miRNAs targeting the FUT3 gene can effectively inhibit the proliferation of KATO-Ⅲ cells.

Regulation of inflammatory breast cancer cell invasion through Akt1/PKBα phosphorylation of RhoC GTPase

With a 42% and 18% 5- and 10-year respective disease-free survival rate, inflammatory breast cancer (IBC) is arguably the deadliest form of breast cancer. IBC invades the dermal lymphatic vessels of the skin overlying the breast and as a consequence nearly all women have lymph node involvement and ~1/3 have gross distant metastases at the time of diagnosis. One year after diagnosis ~90% of patients have detectable metastases, making IBC a paradigm for lymphovascular invasion. Understanding the underlying mechanisms of the IBC metastatic phenotype is essential for new therapies. Work from our laboratory and others show distinct molecular differences between IBC and non-IBCs (nIBCs). Previously we showed that RhoC GTPase is a metastatic switch responsible for the invasive phenotype of IBC. In this study we integrate observations made in IBC patients with in vitro analysis. We show that the PI3K/Akt signaling pathway is crucial in IBC invasion. Key molecules involved in cytoskeletal control and cell motility are specifically upregulated in IBC patients compared with stage and cell-type-of-origin matched nIBCs patients. Distinctively, RhoC GTPase is a substrate for Akt1 and its phosphorylation is absolutely essential for IBC cell invasion. Further our data show that Akt3, not Akt1 has a role in IBC cell survival. Together our data show a unique and targetable pathway for IBC invasion and survival.

Evaluation of lymphangiogenic factors, vascular endothelial growth factor D and E-cadherin in distinguishing inflammatory from locally advanced breast cancer

BACKGROUND

Inflammatory breast cancer (IBC) is an aggressive form of breast cancer that on presentation resembles locally advanced breast cancer (LABC). This study identified molecular features of IBC and LABC to investigate pathogenesis.

MATERIALS AND METHODS

This study involved 100 IBC cases identified in a national IBC registry and 107 non-IBC LABC cases from the National Cancer Institute's Cooperative Breast Cancer Tissue Resource (CBCTR). Vascular endothelial growth factor D (VEGF-D) and E-cadherin levels and lymphatic vessel density (LVD) measured by podoplanin staining were examined by immunohistochemistry on paraffin-embedded tumor specimens. Intralymphatic tumor emboli (ILTE) were assessed in IBC and non-IBC tumors. IBC cases diagnosed by clinicians but not meeting the case definitions of the American Joint Committee on Cancer (AJCC) or the Surveillance, Epidemiology and End Results (SEER) Program of the National Cancer Institute (NCI)(designated atypical IBC) were compared with AJCC- and/or SEER-defined cases (designated classic IBC).

RESULTS

E-cadherin levels were significantly higher in classic IBC cases compared with non-IBC cases (P = .031), whereas compared with classic IBC, patients with non-IBC LABC had significantly higher LVD (P = .0017) and VEGF-D levels (P < .0001). ILTE was marginally greater in classic IBC than in non-IBC (P = .046). The profile of laboratory values in atypical IBC cases more closely resembled those fitting classic IBC than LABC.

CONCLUSION

E-cadherin levels, LVD, VEGF-D expression, and to a lesser extent, ILTE differed between classic IBC and non-IBC LABC. The similarity of laboratory results between atypical IBC and classic IBC vs. LABC suggests the need for broadening both the AJCC and SEER case definitions for this disease.

The lymphovascular embolus of inflammatory breast cancer exhibits a Notch 3 addiction

Inflammatory breast carcinoma (IBC) is characterized by exaggerated lymphovascular invasion (LVI), recapitulated in our human xenograft, MARY-X. This model exhibited lymphovascular emboli in vivo and corresponding spheroids in vitro. Owing to the morphological and gene profile resemblance of these spheroids to embryonal blastocysts, we wondered whether they might exhibit embryonic stem cell signaling. Specifically we investigated Notch and observed selective Notch 3 activation by expression profiling, reverse transcriptase- and real-time PCR, western blot and immunofluorescence in vitro, and immunohistochemistry in vivo. Notch 3 intracellular domain (N3icd) and six target genes, HES-5, HEY-1, c-Myc, Deltex-1, NRARP and PBX1, markedly increased in MARY-X. In addition, a significant percentage of MARY-X cells expressed aldehyde dehydrogenase (ALDH), a stem cell marker. Only the ALDH(+) cells were capable of secondary spheroidgenesis, tumorigenicity and self-renewal. Inhibiting Notch 3 activation in vitro with γ-secretase inhibitors (GSIs) or small interfering RNA resulted in a downregulation of Notch target genes, including CD133, and an induction of caspase 3-mediated apoptosis. Transfection of N3icd but not Notch 1 intracellular domain into normal human mammary epithelial cells resulted in increased expression of Notch target genes and induction of spheroidgenesis. GSI in vivo resulted in inhibitory but diffusion-limited effects on Notch 3 signaling, resulting in xenograft growth reduction. The lymphovascular emboli of human IBC exhibited dual N3icd and ALDH1 immunoreactivities independently of molecular subtype. This Notch 3 addiction of lymphovascular emboli might be exploited in future therapeutic strategies.

Imaging and analysis of 3D tumor spheroids enriched for a cancer stem cell phenotype

Tumors that display a highly metastatic phenotype contain subpopulations of cells that display characteristics similar to embryonic stem cells. These cells exhibit the ability to undergo self-renewal; slowly replicate to retain a nucleoside analog label, leading to their definition as "label-retaining cells"; express specific surface markers such as CD44(+)/CD24(-/low) and CD133; and can give rise to cells of different lineages (i.e., they exhibit multipotency). Based on these characteristics, as well as their demonstrated ability to give rise to tumors in vivo, these cells have been defined as tumor-initiating cells (TICs), tumor-propagating cells, or cancer stem cells (CSCs). These cells are highly resistant to chemotherapeutic agents and radiation and are believed to be responsible for the development of both primary tumors and metastatic lesions at sites distant from the primary tumor. Established cancer cell lines contain CSCs, which can be propagated in vitro using defined conditions, to form 3D tumor spheroids. Because the vast majority of studies to identify cancer-associated genes and therapeutic targets use adherent cells grown in 2 dimensions on a plastic substrate, the multicellular composition of these 3D tumor spheroids presents both challenges and opportunities for their imaging and characterization. The authors describe approaches to image and analyze the properties of CSCs within 3D tumor spheroids, which can serve as the basis for defining the gene and protein signatures of CSCs and to develop therapeutic strategies that will effectively target this critically important population of cells that may be responsible for tumor progression.

Angiogenesis, lymphangiogenesis, growth pattern, and tumor emboli in inflammatory breast cancer: a review of the current knowledge

This objective of the current review was to provide the reader with a comprehensive summary of the literature related to 3 important and inter-related features of the biology of inflammatory breast cancer (IBC): angiogenesis, lymphangiogenesis, and the formation of tumor emboli. Information derived from animal models of IBC as well as from translational studies using tissue samples of patients with IBC are discussed.

Suberoylanilide hydroxamic acid blocks self-renewal and homotypic aggregation of inflammatory breast cancer spheroids

BACKGROUND

Inflammatory breast cancer (IBC) is the most aggressive form of locally advanced breast cancer (LABC). Patients with IBC commonly present with skin metastasis, which are observed microscopically as tumor emboli within dermal lymphatics. These metastatic tumor cells aberrantly overexpress E-cadherin and exhibit the ability to undergo self-renewal and are highly invasive. There are no therapeutics yet identified that target the structure and functions of IBC tumor emboli. The present studies evaluated the effects of the pan-histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) using IBC tumor spheroids derived from established IBC cell lines and tumor spheroids derived from pleural effusion (PE) aspirates of patients with IBC and LABC, designated as PE-IBC and PE-LABC.

METHODS

Methods used are as follows: culture of IBC cells from clonal density single cells in low adherence culture conditions that promote formation of IBC tumor spheroids; clonogenic assays; cell fractionation and Western blotting; confocal microscropy; and modified Boyden chamber invasion assays.

RESULTS

SAHA inhibited self-renewal of IBC tumor spheroids from established IBC cell lines and PE-IBC and PE-LABC, as assessed by decreased clonogenic growth. SAHA blocked homotypic aggregation of the cells that comprised the IBC tumor spheroids leading to loss of their 3-dimensional (3D) structure, which was associated with a change in location of E-cadherin protein from the plasma membrane in untreated IBC tumor spheroids to the cytoplasm of cells within IBC tumor spheroids with SAHA treatment. In addition, SAHA blocked the robust invasion exhibited by IBC tumor spheroids of established cell lines as well as by tumor spheroids derived from PE-IBC and PE-LABC.

CONCLUSIONS

SAHA targets the integrity and biological activities of IBC tumor spheroids and may be a promising agent to evaluate for its effectiveness in treatment of IBC.

A novel sialyltransferase inhibitor AL10 suppresses invasion and metastasis of lung cancer cells by inhibiting integrin-mediated signaling

Aberrant sialylation catalyzed by sialyltransferases (STs) is frequently found in cancer cells and is associated with increased cancer metastasis. However, ST inhibitors developed till now are not applicable for clinical use because of their poor cell permeability. In this study, a novel ST inhibitor AL10 derived from the lead compound lithocholic acid identified in our previous study is synthesized and the anti-cancer effect of this compound is studied. AL10 is cell-permeable and effectively attenuates total sialylation on cell surface. This inhibitor shows no cytotoxicity but inhibits adhesion, migration, actin polymerization and invasion of alpha-2,3-ST-overexpressing A549 and CL1.5 human lung cells. Inhibition of adhesion and migration by AL10 is associated with reduced sialylation of various integrin molecules and attenuated activation of the integrin downstream signaling mediator focal adhesion kinase. More importantly, AL10 significantly suppresses experimental lung metastasis in vivo without affecting liver and kidney function of experimental animals as determined by serum biochemical assays. Taken together, AL10 is the first ST inhibitor, which exhibits potent anti-metastatic activity in vivo and may be useful for clinical cancer treatment.

Hepatospheres: Three dimensional cell cultures resemble physiological conditions of the liver

Studying physiological and pathophysiological mechanisms in the liver on a molecular basis is a challenging task. During two dimensional (2D) culture conditions hepatocytes dedifferentiate rapidly by losing metabolic functions and structural integrity. Hence, inappropriate 2D hepatocellular models hamper studies on the xenobiotic metabolism of the liver which strongly influences drug potency. Also, the lack of effective therapies against hepatocellular carcinoma shows the urgent need for robust models to investigate liver functions in a defined hepatic microenvironment. Here, we summarize and discuss three-dimensional cultures of hepatocytes, herein referred to as hepatospheres, which provide versatile tools to investigate hepatic metabolism, stemness and cancer development.

ERalpha signaling through slug regulates E-cadherin and EMT

The ERalpha signaling pathway is one of the most important and most studied pathways in human breast cancer, yet numerous questions still exist such as how hormonally responsive cancers progress to a more aggressive and hormonally independent phenotype. We have noted that human breast cancers exhibit a strong direct correlation between ERalpha and E-cadherin expression by immunohistochemistry, suggesting that ERalpha signaling might regulate E-cadherin and implying that this regulation might influence epithelial-mesenchymal transition (EMT) and tumor progression. To investigate this hypothesis and the mechanisms behind it, we studied the effects of ERalpha signaling in ERalpha-transfected ERalpha-negative breast carcinoma cell lines, the MDA-MB-468 and the MDA-MB-231 and the effects of ERalpha knockdown in naturally expressing ERalpha-positive lines, MCF-7 and T47D. When ERalpha was overexpressed in the ERalpha-negative lines, 17beta-estradiol (E2) decreased slug and increased E-cadherin. Clones maximally exhibiting these changes grew more in clumps and became less invasive in Matrigel. When ERalpha was knocked down in the ERalpha-positive lines, slug increased, E-cadherin decreased, cells became spindly and exhibited increased Matrigel invasion. ERalpha signaling decreased slug expression by two different mechanisms: directly, by repression of slug transcription by the formation of a corepressor complex of ligand-activated ERalpha, HDAC inhibitor (HDAC1), and nuclear receptor corepressor (N-CoR) that bound the slug promoter in three half-site estrogen response elements (EREs); indirectly by phosphorylation and inactivation of GSK-3beta through phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt). The GSK-3beta inactivation, in turn, repressed slug expression and increased E-cadherin. In human breast cancer cases, there was a strong inverse correlation between slug and ERalpha and E-cadherin immunoreactivity. Our findings indicate that ERalpha signaling through slug regulates E-cadherin and EMT.

Gain in cellular organization of inflammatory breast cancer: A 3D in vitro model that mimics the in vivo metastasis

Background

The initial step of metastasis in carcinomas, often referred to as the epithelial-mesenchymal transition (EMT), occurs via the loss of adherens junctions (e.g. cadherins) by the tumor embolus. This leads to a subsequent loss of cell polarity and cellular differentiation and organization, enabling cells of the embolus to become motile and invasive. However highly malignant inflammatory breast cancer (IBC) over-expresses E-cadherin. The human xenograft model of IBC (MARY-X), like IBC, displays the signature phenotype of an exaggerated degree of lymphovascular invasion (LVI) in situ by tumor emboli. An intact E-cadherin/α, β-catenin axis mediates the tight, compact clump of cells found both in vitro and in vivo as spheroids and tumor emboli, respectively.

Methods

Using electron microscopy and focused ion beam milling to acquire in situ sections, we performed ultrastructural analysis of both an IBC and non-IBC, E-cadherin positive cell line to determine if retention of this adhesion molecule contributed to cellular organization.

Results

Here we report through ultrastructural analysis that IBC exhibits a high degree of cellular organization with polar elements such as apical/lateral positioning of E-cadherin, apical surface microvilli, and tortuous lumen-like (canalis) structures. In contrast, agarose-induced spheroids of MCF-7, a weakly invasive E-cadherin positive breast carcinoma cell line, do not exhibit ultrastructural polar features.

Conclusions

This study has determined that the highly metastatic IBC with an exaggerated malignant phenotype challenges conventional wisdom in that instead of displaying a loss of cellular organization, IBC acquires a highly structured architecture.

These findings suggest that the metastatic efficiency might be linked to the formation and maintenance of these architectural features. The comparative architectural features of both the spheroid and embolus of MARY-X provide an in vitro model with tractable in vivo applications.

Aldehyde dehydrogenase 1-positive cancer stem cells mediate metastasis and poor clinical outcome in inflammatory breast cancer

PURPOSE

To examine the role of cancer stem cells (CSC) in mediating metastasis in inflammatory breast cancer (IBC) and the association of these cells with patient outcome in this aggressive type of breast cancer.

EXPERIMENTAL DESIGN

CSCs were isolated from SUM149 and MARY-X, an IBC cell line and primary xenograft, by virtue of increased aldehyde dehydrogenase (ALDH) activity as assessed by the ALDEFLUOR assay. Invasion and metastasis of CSC populations were assessed by in vitro and mouse xenograft assays. Expression of ALDH1 was determined on a retrospective series of 109 IBC patients and this was correlated with histoclinical data. All statistical tests were two sided. Log-rank tests using Kaplan-Meier analysis were used to determine the correlation of ALDH1 expression with development of metastasis and patient outcome.

RESULTS

Both in vitro and xenograft assays showed that invasion and metastasis in IBC are mediated by a cellular component that displays ALDH activity. Furthermore, expression of ALDH1 in IBC was an independent predictive factor for early metastasis and decreased survival in this patient population.

CONCLUSIONS

These results suggest that the metastatic, aggressive behavior of IBC may be mediated by a CSC component that displays ALDH enzymatic activity. ALDH1 expression represents the first independent prognostic marker to predict metastasis and poor patient outcome in IBC. The results illustrate how stem cell research can translate into clinical practice in the IBC field.

Inflammatory breast cancer

Inflammatory breast cancer (IBC) represents the most virulent form of breast cancer, characterized by involvement of the skin and rapid progression of the disease. Management involves careful coordination of all multidisciplinary modalities, including imaging, systemic chemotherapy, surgery, and radiation therapy. The use of neoadjuvant chemotherapy has contributed significantly to improvement in overall survival since the first descriptions of this entity and has made the role of locoregional therapy, including surgery and radiation critical to continued improvements in this disease. In this article, we examine the unique epidemiology and pathology of IBC and review the various treatment modalities noting the significance of a multimodality approach and delineating each of the specific components. Moreover, we briefly describe the current research in IBC that will hopefully contribute further to improve systemic therapies.

Molecular plasticity of E-cadherin and sialyl lewis x expression, in two comparative models of mammary tumorigenesis

Background

The process of metastasis involves a series of steps and interactions between the tumor embolus and the microenvironment. Key alterations in adhesion molecules are known to dictate progression from the invasive to malignant phenotype followed by colonization at a distant site. The invasive phenotype results from the loss of expression of the E-cadherin adhesion molecule, whereas the malignant phenotype is associated with an increased expression of the carbohydrate ligand-binding epitopes, (e.g. Sialyl Lewis ^x/a) that bind endothelial E-selectin of the lymphatics and vasculature.

Methodology

Our study analyzed the expression of two adhesion molecules, E-cadherin and Sialyl Lewis x (sLe^x), in both a canine mammary carcinoma and human inflammatory breast cancer (IBC) model, using double labelled immunofluorescence staining.

Results

Our results demonstrate that canine mammary carcinoma and human IBC exhibit an inversely correlated cellular expression of E-cadherin and sLe^x within the same tumor embolus.

Conclusions

Our results in these two comparative models (canine and human) suggest the existence of a biologically coordinated mechanism of E-cadherin and sLe^x expression (i.e. molecular plasticity) essential for tumor establishment and metastatic progression.

E-selectin and Sialyl Lewis X Expression Is Associated With Lymph Node Metastasis of Invasive Micropapillary Carcinoma of the Breast

To investigate the possible roles of E-selectin and its ligand, Sialyl Lewis X, in lymph node metastasis of invasive micropapillary carcinoma of the breast, 100 cases of invasive micropapillary carcinoma and 97 cases of invasive ductal carcinoma were analyzed immunohistochemically for the expression of E-selectin and Sialyl Lewis X, along with CD34, to measure the microvessel density of invasive micropapillary carcinoma. We found that the number of E-selectin—positive vessels was greater in invasive micropapillary carcinoma than in invasive ductal carcinoma, and it was significantly correlated with the histological grade, the number of positive lymph nodes, and the microvessel density of invasive micropapillary carcinoma. The Sialyl Lewis X expression of invasive micropapillary carcinoma was higher than that of invasive ductal carcinoma, which was also associated with lymph node metastasis. In invasive micropapillary carcinoma, the Sialyl Lewis X expression was predominantly in the stroma-facing surface of the cell clusters and the adjacent stroma, while in invasive ductal carcinoma it was largely intracytoplasmic or intercellular. These findings suggested that E-selectin and Sialyl Lewis X might play an important role in lymph node metastasis in invasive micropapillary carcinoma. The expression pattern of Sialyl Lewis X in invasive micropapillary carcinoma suggested that the reversal of cell polarity of invasive micropapillary carcinoma might be as an important factor for the morphogenesis and possibly the pathogenesis, especially their higher rates of lymph node metastasis.

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

Inflammatory breast carcinoma (IBC) is a particularly lethal form of breast cancer characterized by exaggerated lymphovascular invasion, which is a phenotype recapitulated in our human xenograft MARY-X. MARY-X generated spheroids in vitro that resemble the embryonal blastocyst. Because of the resemblance of the spheroids to the embryonal blastocyst and their resistance to traditional chemotherapy/radiotherapy, we hypothesized that the spheroids expressed a stem cell-like phenotype. MARY-X spheroids expressed embryonal stem cell markers including stellar, rex-1, nestin, H19, and potent transcriptional factors, oct-4, nanog, and sox-2, which are associated with stem cell self-renewal and developmental potential. Most importantly, MARY-X spheroids expressed a cancer stem cell profile characterized by CD44(+)/CD24(-/low), ALDH1, and most uniquely, CD133. A significant percentage of single cells of MARY-X exhibited distinct proliferative and morphogenic potencies in vitro. As few as 100 cells derived from single-cell clonogenic expansion were tumorigenic with recapitulation of the IBC phenotype. Prototype stem cell signaling pathways such as notch3 were active in MARY-X. The stem cell phenotype exhibited by MARY-X also was exhibited by the lymphovascular emboli of human IBC cases independent of their molecular subtype. This stem cell-like phenotype may contribute to the aggressive nature of IBC but also may lend itself to selective targeting.

Defining the molecular biology of inflammatory breast cancer

Inflammatory breast cancer (IBC) is a rare, but aggressive form of breast cancer. Despite the progress related to the introduction of primary combination chemotherapy (CT) to the multimodality treatment regimen, the prognosis of IBC remains poor with long-term survival inferior to 50%. Until recently, IBC remained understudied at the molecular level. In the past 10 years, advances have been made in the molecular characterization of the disease. Recently, the use of experimental models and new high-throughput molecular profiling technologies have led to the identification of genes or pathways potentially involved in disease development, which might represent new clinically relevant targets. The aim of this review is to present and discuss what is known about the biology of this particularly aggressive form of breast cancer and to discuss how this knowledge could improve its management.

Pathologic aspects of inflammatory breast cancer: part 2. Biologic insights into its aggressive phenotype

Inflammatory breast cancer (IBC) is the most aggressive and distinct form of primary breast cancer with a peculiar clinical presentation and dismal clinical outcome. This review addresses the pathologic aspects of this entity and discusses the molecular alterations involved in the highly malignant phenotype of IBC.

Inflammatory breast cancer: current understanding

PURPOSE OF REVIEW

Inflammatory breast cancer is a highly aggressive variant of locally advanced breast cancer that carries a significantly worse prognosis. The purpose of this review is to highlight recent advances in the molecular modus operandi of this particular form of breast cancer.

RECENT FINDINGS

Studies on tumor cell emboli, E-cadherin, chemokine receptors, steroid hormone receptor, angiogenesis, lymphangiogenesis and gene expression all suggest significant differences with noninflammatory breast cancer and are clearly in line with a different pathogenesis of the condition.

SUMMARY

This comprehensive review will hopefully allow for better treatment modalities with targeted approaches as suggested by the early data on anti-vascular endothelial growth factor treatment in inflammatory breast cancer.

Inflammatory breast cancers in Tunisia and France show similar immunophenotypes

PURPOSE

Inflammatory breast cancers (IBC) have specific immunophenotypic profiles as compared to non-inflammatory (non-IBC): combined differential expression of estrogen receptor, Ki67, E-cadherin, MUC1, and ERBB2 can be used as an IBC signature. It is thought that IBC occurs with a high frequency in Tunisia. The aim of this study is to evaluate this signature on a Tunisian series.

METHODS

The expression of five proteins (E-cadherin, ERBB2, estrogen receptor, Ki67, MUC1) was studied by immunohistochemistry on a consecutive series of 91 cases of IBC (T4D) treated at Tunisian Salah Azaiz Institute (ISA) and deposited in a tissue microarray (TMA). Results were compared to the same study on a series of 85 cases treated in France.

RESULTS

The ISA cases were characterized by a significantly younger age of patients (median: 42 years old in ISA for 53.5 in IPC, p=0.00042) and a higher frequency of invasive micropapillary pattern. None of the five parameters was expressed differentially in the two series. In non-metastatic patients, high level of proliferation (Ki67) and overexpression of ERBB2 were associated with poor outcome.

CONCLUSION

The IBC from Tunisia were not different from those observed in France on the basis of IHC profiles. However, the younger age of the patients suggest a specific epidemiological context that should be investigated.

Sialyl Lewis x expression in canine malignant mammary tumours: correlation with clinicopathological features and E-Cadherin expression

Background

Sialyl Lewis x (sLe^x) antigen is a carbohydrate antigen that is considered not only a marker for cancer but also implicated functionally in the malignant behaviour of cancer cells. Overexpression of sLe^x is associated with enhanced progression and metastases of many types of cancer including those of the mammary gland. Canine mammary tumours can invade and give rise to metastases via either lymphatic or blood vessels.

E-Cadherin is specifically involved in epithelial cell-to-cell adhesion. In cancer, E-Cadherin underexpression is one of the alterations that characterizes the invasive phenotype and is considered an invasion/tumour suppressor gene. Partial or complete loss of E-Cadherin expression correlates with poor prognosis in canine malignant mammary cancer.

The aim of this study was to analyse the sLe^x expression in canine malignant mammary tumours and to evaluate if the presence of sLe^x correlates with the expression of E-Cadherin and with clinicopathological features.

Methods

Fifty-three cases of canine mammary carcinomas were analysed immunohistochemically using monoclonal antibodies against sLe^x (IgM) and E-Cadherin (IgG). The clinicopathological data were then assessed to determine whether there was a correlation with sLe^x tumour expression. Double labelled immunofluorescence staining was performed to analyse the combined expression of sLe^x and E-Cadherin.

Results

sLe^x expression was consistently demonstrated in all cases of canine mammary carcinomas with different levels of expression. We found a significant relationship between the levels of sLe^x expression and the presence of lymph node metastases. We also demonstrated that when E-Cadherin expression was increased sLe^x was reduced and vice-versa. The combined analysis of both adhesion molecules revealed an inverse relationship.

Conclusion

In the present study we demonstrate the importance of sLe^x in the malignant phenotype of canine malignant mammary tumours. Our results support the use of sLe^x as a prognostic tumour marker in canine mammary carcinomas. Furthermore, we showed that sLe^x and E-Cadherin expression were inversely correlated. Future studies are warranted to clarify the molecular mechanism underlying the relation between sLe^x and E-Cadherin in canine mammary carcinoma cells which represents an important comparative model to woman breast cancer.

Targeted Therapy with a Salmonella Typhimurium Leucine-Arginine Auxotroph Cures Orthotopic Human Breast Tumors in Nude Mice

We report here a modified auxotrophic strain of Salmonella typhimurium that can target and cure breast tumors in orthotopic mouse models. We have previously reported development of a genetically modified strain of S. typhimurium, selected for prostate tumor targeting and therapy in vivo. The strain, termed S. typhimurium A1, selectively grew in prostate tumors in xenograft models causing tumor regression. In contrast, normal tissue was cleared of these bacteria even in immunodeficient athymic mice with no apparent side effects. A1 is auxotrophic (leucine-arginine dependent) but apparently receives sufficient nutritional support only from tumor tissue. The ability to grow in viable tumor tissue may account, in part, for the unique antitumor efficacy of the strain. In the present report, to increase tumor-targeting capability of A1, the strain was reisolated after infection of a human colon tumor growing in nude mice. The tumor-isolated strain, termed A1-R, had increased targeting for tumor cells in vivo as well as in vitro compared with A1. Treatment with A1-R resulted in highly effective tumor targeting, including viable tumor tissue and significant tumor shrinkage in mice with s.c. or orthotopic human breast cancer xerographs. Survival of the treated animals was significantly prolonged. Forty percent of treated mice were cured completely and survived as long as non-tumor-bearing mice. These results suggest that amino acid auxotrophic virulent bacteria, which selectively infect and attack viable tumor tissue, are a promising approach to cancer therapy.

Dynamic analysis of hepatoma spheroid formation: roles of E-cadherin and β1-integrin

A spheroid is an in vitro multicellular aggregate that provides a microenvironment resembling that of normal tissue in vivo. Although cell adhesion molecules such as integrins and cadherins have been implicated in participating in the process of spheroid formation, little is known about the timing of their action. In this study, we have employed an image-based quantitative method to investigate the compactness of cell aggregates during hepatoma spheroid formation in a dynamic fashion. By modulating beta1-integrin and E-cadherin activity with specific blocking antibodies, ion chelators, and RGD-sequence-containing peptides, we show that these cell adhesion molecules mediate the formation of spheroids through the establishment of complex cell-cell and cell-extracellular matrix (ECM) interactions. The dynamics of spheroid formation can be separated into three stages. In the first stage, ECM fibers act as a long-chain linker for the attachment of dispersed single-cells to form loose aggregations through the binding of integrins. This is followed by a delay period in which cell aggregates pause in compaction, presumably because of the accumulation of sufficient amounts of E-cadherins. In the third stage, strong homophilic interaction of E-cadherins is a major factor for the morphological transition from loose cell aggregates to compact spheroids. These findings thus provide comprehensive information on the molecular mechanisms and dynamics of hepatoma spheroid formation.

Diagnosis, treatment and prognosis of internal mammary lymph node recurrence in breast cancer patients

Recurrences in the internal mammary lymph nodes (IMLN) are very rare, despite the fact that these nodes remain untreated in most patients. The aim of this study was to assess the chance for IMLN recurrence in a large patient series and to get insight into diagnostics, treatment and prognosis of this type of recurrence. Follow-up of nearly 6000 breast cancer patients resulted in the tracing of only six patients with IMLN recurrence. IMLN recurrence was defined as breast cancer recurrence in an internal mammary lymph node without a distant metastasis before the recurrence and confirmed by cytology and/or CT-scan. The time interval between diagnosis of the primary tumor and the recurrence varied between 5 months and 8 years and 6 months. One patient showed no symptoms, the other five all had a swelling and one of them also had pain. The size of the parasternal swelling varied from 30 to 90 mm; in one patient the size was unknown. Treatment resulted in a complete remission in four patients. In five of the six patients distant metastases occurred. The time interval between IMLN recurrence and the diagnosis of distant metastasis varied between 0 and 37 months. One patient was still free of distant metastasis in the time of this study. This large population-based study confirms the almost negligible risk of clinically apparent IMLN recurrence. Considering the high percentage of positive lymph nodes in studies evaluating sentinel node biopsy of the internal mammary chain, it becomes clear that just a fraction of these becomes clinically apparent as a recurrence. In almost all patients with IMLN it is a forerunner of metastatic disease.

Deficiency in surface expression of E-selectin ligand promotes lung colonization in a mouse model of breast cancer

Expression of sialyl Lewis(x) (sLe(x)) and sLe(a) on tumor cells is thought to facilitate metastasis by promoting cell adhesion to selectins on vascular endothelial cells. Experiments supporting this concept usually bypass the early steps of the metastatic process by employing tumor cells that are injected directly into the blood. We investigated the relative role of sLe(x) oligosaccharide in the dissemination of breast carcinoma, employing a spontaneous murine metastasis model. An sLe(x) deficient subpopulation of the 4T1 mammary carcinoma cell line was produced by negative selection using the sLe(x)-reactive KM93 MAb. This subpopulation was negative for E-selectin binding but retained P-selectin binding. Both sLe(x)-negative and -positive cells grew at the same rate; however, sLe(x)-negative cells spread more efficiently on plates and had greater motility in wound-scratch assays. Mice inoculated in the mammary fat pad with sLe(x)-negative and -positive variants produced lung metastases. However, the number of lung metastases was significantly increased in the group inoculated with the sLe(x)-negative variant (p = 0.0031), indicating that negative selection for the sLe(x) epitope resulted in enrichment for a subpopulation of cells with a high metastatic phenotype. Cell variants demonstrated significant differences in cellular morphology and pattern of tumor growth in primary and secondary tumor sites. These results strongly suggest that loss of sLe(x) may facilitate the metastatic process by contributing to escape from the primary tumor mass.

Relevance of breast cancer cell lines as models for breast tumours: an update

The number of available breast cancer cell (BCC) lines is small, and only a very few of them have been extensively studied. Whether they are representative of the tumours from which they originated remains a matter of debate. Whether their diversity mirrors the well-known inter-tumoural heterogeneity is another essential question. While numerous similarities have long been found between cell lines and tumours, recent technical advances, including the use of micro-arrays and comparative genetic analysis, have brought new data to the discussion. This paper presents most of the BCC lines that have been described in some detail to date. It evaluates the accuracy of the few of them widely used (MCF-7, T-47D, BT-474, SK-BR-3, MDA-MB-231, Hs578T) as tumour models. It is concluded that BCC lines are likely to reflect, to a large extent, the features of cancer cells in vivo. The importance of oestrogen receptor-alpha (gene ESR1 ) and Her-2/ neu ( ERBB2 ) as classifiers for cell lines and tumours is underlined. The recourse to a larger set of cell lines is suggested since the exact origin of some of the widely used lines remains ambiguous. Investigations on additional specific lines are expected to improve our knowledge of BCC and of the dialogue that these maintain with their surrounding normal cells in vivo.