BackgroundLimited understanding of the cancer biology of metastatic sites is a major factor contributing to poor outcomes in cancer patients. The regional lymph nodes are the most common site of metastasis in most solid cancers and their involvement is a strong predictor of relapse in breast cancer (BC). We have previously shown that ezrin, a cytoskeletal–membrane linker protein, is associated with lymphovascular invasion and promotes metastatic progression in BC. However, the efficacy of pharmacological inhibition of ezrin in blocking cancer cell migration and metastasis remains unexplored in BC.MethodsWe quantified ezrin expression in a BC tissue microarray (n = 347) to assess its correlation with risk of relapse. Next, we developed a quantitative intravital microscopy (qIVM) approach, using a syngeneic lymphatic reporter mouse tumor model, to investigate the effect of systemic ezrin inhibition on cancer cell migration and metastasis.ResultsWe show that ezrin is expressed at significantly higher levels in lymph node metastases compared to matched primary tumors, and that a high tumor ezrin level is associated with increased risk of relapse in BC patients with regional disease. Using qIVM, we observe a subset of cancer cells that retain their invasive and migratory phenotype at the tumor-draining lymph node. We further show that systemic inhibition of ezrin, using a small molecule compound (NSC668394), impedes the migration of cancer cells in vivo. Furthermore, systemic ezrin inhibition leads to reductions in metastatic burden at the distal axillary lymph node and lungs.ConclusionsOur findings demonstrate that the tumor ezrin level act as an independent biomarker in predicting relapse and provide a rationale for therapeutic targeting of ezrin to reduce the metastatic capacity of cancer cells in high-risk BC patients with elevated ezrin expression.Electronic supplementary materialThe online version of this article (10.1186/s13058-018-1079-7) contains supplementary material, which is available to authorized users.

The non-receptor tyrosine kinase Fer belongs to a distinct subfamily of F-BAR domain containing kinases implicated in vesicular trafficking and signaling downstream of adhesion and growth factor receptors. Targeted inactivation of the fer gene in a transgenic mouse model of HER2(+), breast cancer was associated with delayed tumor onset and reduced proliferative rates in tumor cells. Fer deficiency was associated with increased rates of epidermal growth factor (EGF)-induced epidermal growth factor receptor (EGFR) internalization and amplified Ras-Raf-Mek-Erk (Ras-MAPK) signaling in primary mammary tumor epithelial cells, as well as increased cytotoxic and anti-proliferative sensitivity to the dual EGFR/HER2 inhibitor Lapatinib (LPN). These observations suggest a model in which accelerated ligand-induced EGFR internalization in Fer-deficient cells hypersensitizes the Ras-MAPK pathway to EGF, resulting in MAPK signal amplification to levels that induce cytostasis, rather than proliferation. Thus, Ras-MAPK cytostatic signaling delays HER2 tumor initiation and increases LPN cytotoxicity in Fer-deficient model systems. Taken together, these data suggest that targeting Fer alone, or in combination with LPN, may be of therapeutic benefit in HER2(+) breast cancer.

Two beetle-type scanning tunneling microscopes are described. Both designs have the thermal stability of the Besocke beetle and the simplicity of the Wilms beetle. Moreover, sample holders were designed that also allow both semiconductor wafers and metal single crystals to be studied. The coarse approach is a linear motion of the beetle towards the sample using inertial slip-stick motion. Ten wires are required to control the position of the beetle and scanner and measure the tunneling current. The two beetles were built with different sized piezo-legs, and the vibrational properties of both beetles were studied in detail. It was found, in agreement with previous work, that the beetle bending mode is the lowest principal eigenmode. However, in contrast to previous vibrational studies of beetle-type scanning tunneling microscopes, we found that the beetles did not have the 'rattling' modes that are thought to arise from the beetle sliding or rocking between surface asperities on the raceway. The mass of our beetles is 3-4 times larger than the mass of beetles where rattling modes have been observed. We conjecture that the mass of our beetles is above a 'critical beetle mass'. This is defined to be the beetle mass that attenuates the rattling modes by elastically deforming the contact region to the extent that the rattling modes can't be identified as distinct modes in cross-coupling measurements.

A high-brightness, low energy electron source and dual Geiger-Müller-type isochromat photon detectors are combined to create a versatile new inverse photoemission system. The bandpass of the photon detector can be set to one of the following discrete values: 0.37Ϯ0.02, 0.43Ϯ0.02, 0.56Ϯ0.02, or 0.73Ϯ0.04 eV by using ethanol, 1-propanol, 1-butanol, or a dimethyl ether/ethanol mixture, respectively, as the detection gas͑es͒. All of the alcohols are self-quenching and do not require the addition of a quench gas. The design of the photon detectors, the electron gun, and the circuits that perform the dead time gating are described in detail. The capabilities of the new system are illustrated using spectra from both metal ͑Cu͒ and semiconductor ͑Si͒ surfaces.

ObjectiveInterleukin-4 (IL-4) can induce macrophages to undergo alternative activation and polarize toward an M2-like or wound healing phenotype. Tumor associated macrophages (TAMs) are thought to assume M2-like properties, and it has been suggested they promote tumor growth and metastasis through effects on the tumor stroma, including extracelluar matrix remodeling and angiogenesis. IL-4 also promotes macrophage survival and formation of multinucleated giant cells, which have enhanced phagocytic behavior. This study was designed to explore the effect of cancer cell derived IL-4 on the tumor immune stroma and metastasis.MethodsThe metastatic mouse mammary carcinoma cell line AC2M2 was transduced with control or IL-4 encoding retroviruses and employed in orthotopic engraftment models. Tumor growth and metastasis were assessed. The cellular composition and biomarker expression of tumors were examined by immunohistochemical staining and flow cytometry; the transcriptome of the immune stroma was analyzed by nanoString based transcript quantitation; and in vivo and in vitro interactions between cancer cells and macrophages were assessed by flow cytometry and co-culture with video-time lapse microscopy, respectively.ResultsUnexpectedly, tumors from IL-4 expressing AC2M2 engrafted cells grew at reduced rates, and most surprising, they lost all metastatic potential relative to tumors from control AC2M2 cells. Myeloid cell numbers were not increased in IL-4 expressing tumors, but their expression of the M2 marker arginase I was elevated. Transcriptome analysis revealed an immune signature consistent with IL-4 induced M2 polarization of the tumor microenvironment and a generalized increase in myeloid involvement in the tumor stroma. Flow cytometry analysis indicated enhanced cancer cell phagocytosis by TAMs from IL-4 expressing tumors, and co-culture studies showed that IL-4 expressing cancer cells supported the survival and promoted the in vitro phagocytic behavior of macrophages.ConclusionsAlthough M2-like TAMs have been linked to enhanced tumorigenesis, this study shows that IL-4 production by cancer cells is associated with suppressed tumor growth and loss of metastatic potential as well as enhanced phagocytic behavior of TAMs.