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The bottleneck arising from castration-resistant prostate cancer (CRPC) treatment is its high metastasis potential and antiandrogen drug resistance, which severely affects survival time of prostate cancer (PCa) patients. Secreted phosphoprotein 1 (SPP1) is a cardinal mediator of tumor-associated inflammation and facilitates metastasis. In our previous study, we firstly revealed SPP1 was a potential hub signature for predicting metastatic CRPC (mCRPC) development. Herein, we integrated multiple databases to explore the association of SPP1 expression with prognosis, survival, and metastatic levels in CRPC progression and investigated SPP1 expression in PCa tissues and cell lines. Next, PCa cell lines with overexpression or depletion of SPP1 were established to study the effect of SPP1 on enzalutamide sensitivity and adhesion and migration of prostate cancer cell lines and further explore the underlying regulatory mechanisms. Bioinformatics analysis, polymerase chain reaction (PCR), immunohistochemical staining, and western blot results suggested SPP1 upregulation had strong relationship with the malignant progression of CRPC and enzalutamide resistance. SPP1 knockdown enhanced enzalutamide sensitivity and repressed invasion and migration of prostate cancer cells. Importantly, upregulating SPP1 promoted, while silencing SPP1 attenuated epithelial-mesenchymal-transition (EMT). Our results further demonstrated that SPP1 overexpression maintains the activation of PI3K/AKT and ERK1/2 signaling pathways. Overall, our findings unraveled the functional role and clinical significance of SPP1 in PCa progression and help to discover new potential targets against mCRPC.

Background As one of the non-pharmacological interventions to control the transmission of COVID-19, determining the quarantine duration is mainly based on the accurate estimates of the incubation period. However, patients with coarse information of the exposure date, as well as infections other than the symptomatic, were not taken into account in previously published studies. Thus, by using the statistical method dealing with the interval-censored data, we assessed the quarantine duration for both common and uncommon infections. The latter type includes the presymptomatic, the asymptomatic and the recurrent test positive patients. Methods As of 10 December 2020, information on cases have been collected from the English and Chinese databases, including Pubmed, Google scholar, CNKI (China National Knowledge Infrastructure) and Wanfang. Official websites and medias were also searched as data sources. All data were transformed into doubly interval-censored and the accelerated failure time model was applied. By estimating the incubation period and the time-to-event distribution of worldwide COVID-19 patients, we obtain the large percentiles for determining and suggesting the quarantine policies. For symptomatic and presymptomatic COVID-19 patients, the incubation time is the duration from exposure to symptom onset. For the asymptomatic, we substitute the date of first positive result of nucleic acid testing for that of symptom onset. Furthermore, the time from hospital discharge or getting negative test result to the positive recurrence has been calculated for recurrent positive patients. Results A total of 1920 laboratory confirmed COVID-19 cases were included. Among all uncommon infections, 34.1% (n = 55) of them developed symptoms or were identified beyond fourteen days. Based on all collected cases, the 95th and 99th percentiles were estimated to be 16.2 days (95% CI 15.5–17.0) and 22.9 days (21.7‒24.3) respectively. Besides, we got similar estimates based on merely symptomatic and presymptomatic infections as 15.1 days (14.4‒15.7) and 21.1 days (20.0‒22.2). Conclusions There are a certain number of infected people who require longer quarantine duration. Our findings well support the current practice of the extended active monitoring. To further prevent possible transmissions induced and facilitated by such infectious outliers after the 14-days quarantine, properly prolonging the quarantine duration could be prudent for high-risk scenarios and in regions with insufficient test resources.

This study identifies a novel population of CD204+IL4R+ bone metastasis–associated macrophages (BoMAMs) in mouse models and patient samples. These BoMAMs, derived from CCR2-recruited monocytes but not from CD169+ resident macrophages, significantly promote metastatic outgrowth of breast cancer in vivo., Bone metastasis is the major cause of death in breast cancer. The lack of effective treatment suggests that disease mechanisms are still largely unknown. As a key component of the tumor microenvironment, macrophages promote tumor progression and metastasis. In this study, we found that macrophages are abundant in human and mouse breast cancer bone metastases. Macrophage ablation significantly inhibited bone metastasis growth. Lineage tracking experiments indicated that these macrophages largely derive from Ly6C+CCR2+ inflammatory monocytes. Ablation of the chemokine receptor, CCR2, significantly inhibited bone metastasis outgrowth and prolonged survival. Immunophenotyping identified that bone metastasis–associated macrophages express high levels of CD204 and IL4R. Furthermore, monocyte/macrophage-restricted IL4R ablation significantly inhibited bone metastasis growth, and IL4R null mutant monocytes failed to promote bone metastasis outgrowth. Together, this study identified a subset of monocyte-derived macrophages that promote breast cancer bone metastasis in an IL4R-dependent manner. This suggests that IL4R and macrophage inhibition can have potential therapeutic benefit against breast cancer bone disease., Graphical Abstract

While the novel coronavirus continues to spread worldwide, the reported incubation period has varied between studies and is imprecise due to limited data. A literature search with certain selection criteria was conducted on May 30, 2020. In total, sixty-four articles were included, and 854 individual-level data were extracted from 30 studies for pooled analysis. Of these studies, 72% of them reported a median or mean incubation period of 4-7 days, while our estimated median was 4.9 days (95% confidence interval [CI]: 4.6-5.2). However, the inclusion of 81 asymptomatic and presymptomatic patients, as well as 31 cases with incubation periods exceeding 14 days, led to our estimation of 97.5 th percentile with 19.3 days (95% CI: 17.4-21.4), beyond the currently suggested 14-day quarantine period. Therefore, we appeal to prolong the quarantine duration, especially for areas that have insufficient testing resources, to protect susceptible populations from being infected.Article Summary LineThis article reviewed the COVID-19 studies involving incubation period and provided pooled estimation based on available data from these studies.The result showed that our estimated median incubation period is consistent with the estimates of formal studies but the 97.5 percentile is larger than ever on account of including a number of asymptomatic and presymptomatic patients.These finds suggested that we should properly prolong the isolation or quarantine period in order to identify more patients with longer incubation period and those without any symptoms.

Metastatic disease is the major challenge of cancer that accounts for over 90% of total cancer lethality. Mounting clinical and preclinical data now indicate that inflammation, a potent immune and repair response, is indispensable for metastasis. In this review we describe our current understanding of how major inflammatory cells contribute to metastatic cascade with a focus on the primary tumour. We also discuss exciting new directions for future research and novel therapeutic approaches to tackle metastatic disease through targeting inflammation.

The purpose of this study is to investigate the accuracy and safety of intracavitary electrocardiogram (IC-ECG) guidance for the localization of peripherally inserted central catheter (PICC) in neonatal patients. A total of 160 neonatal patients were randomly assigned to receive either anthropometric measurement combined with IC-ECG guidance (n = 80) or conventional anatomical landmark guidance (n = 80) for PICC catheter tip positioning. The catheter tip position was confirmed by postinsertion radiograph and data were interpreted by independent radiologists. Subsequent catheter-related complications of neonates between 2 groups were also compared. The first-attempt target rate was 95.0% (95% confidence interval, 90.1%-99.9%) in IC-ECG-guided PICCs, significantly higher than 78.8% (95% confidence interval, 69.6%-87.9%) in the anatomical landmark guidance group (P < .05). In contrast, IC-ECG-guided PICCs provided a significantly lower overall incidence of the catheter-related complications (3.75%), compared with those guided by anatomical landmarks only (23.75%). Thus, combined use of anatomical landmark and IC-ECG guidance improved the first-attempt target rate of PICC placement and decreased catheter-related complications. These findings indicated a superior accuracy and safety of IC-ECG guidance to conventional anatomical landmark method in neonatal PICC practice.

Bone metastasis is the most advanced stage of many cancers and indicates a poor prognosis for patients due to resistance to anti-tumor therapies. The establishment of metastasis within the bone is a multistep process. To ensure survival within the bone marrow, tumor cells must initially colonize a niche in which they can enter dormancy. Subsequently, reactivation permits the proliferation and growth of the tumor cells, giving rise to a macro-metastasis displayed clinically as a bone metastatic lesion. Here, we review the evidences that suggest mesenchymal stromal cells play an important role in each of these steps throughout the development of bone metastasis. Similarities between the molecular mechanisms implicated in these processes and those involved in the homeostasis of the bone indicate that the metastatic cells may exploit the homeostatic processes to their own advantage. Identifying the molecular interactions between the mesenchymal stromal cells and tumor cells that promote tumor development may offer insight into potential therapeutic targets that could be utilized to treat bone metastasis.

Prostate cancer is the most common cancer among men worldwide. However, current treatments for prostate cancer patients in advanced stage often fail because of relapse. Prostate cancer stem cells (PCSCs) are resistant to most standard therapies, and are considered to be a major mechanism of cancer metastasis and recurrence. In this review, we summarized current understanding of PCSCs and their self-renewal signaling pathways with a specific focus on Wnt signaling. Although multiple Wnt inhibitors have been developed to target PCSCs, their application is still limited by inefficient delivery and toxicity in vivo. Recently, nanotechnology has opened a new avenue for cancer drug delivery, which significantly increases specificity and reduces toxicity. These nanotechnology-based drug delivery methods showed great potential in targeting PCSCs. Here, we summarized current advancement of nanotechnology-based therapeutic strategies for targeting PCSCs and highlighted the challenges and perspectives in designing future therapies to eliminate PCSCs.

In view of local feature weighting hard c-means (LWHCM) clustering algorithm sensitive to noise, based on a non-Euclidean metric, a robust local feature weighting hard c-means (RLWHCM) clustering algorithm is presented. RLWHCM is a natural, effective extension of LWHCM. The robustness of RLWHCM is analyzed by using the location M-estimate in robust statistical theory. The convergence proof of RLWHCM is given. Experimental results on synthetic and real-world data sets demonstrate the effectiveness of the proposed algorithm.

In China, surface subsidence caused by steep coal seam mining has affected the safe operation of pipelines in recent years. The study site is one coal mine, where the gas pipeline from Shanshan to Urumqi is across. FLAC3D was adopted to study subsidence-induced stress on the pipeline, and the numerical model was calibrated with the measurement data. Visualization of alarm levels on the pipeline was obtained by integrating the usage of Fish function embedded in FLAC3D and Tecplot. The simulations reveal that the stress on the pipeline is closely related to the excavation depth. The stress on the pipeline increases with the excavation depth increasing when mining the 1st, 2nd, and 3rd levels, whereas the stress on the pipeline decreases slightly with the excavation depth increasing when mining the fourth, fifth, and sixth levels. The maximum stress on the pipeline occurs after mining the 3rd level. The possible damage to the pipe is at the upper-right side. Therefore, the results are helpful to prevent and reduce the impact of subsidence on the pipeline.

Linear Discriminant Analysis (LDA) is a classical statistical approach for supervised feature extraction and dimensionality reduction, hard c-means (HCM) is a classical unsupervised learning algorithm for clustering. Based on the analysis of the relationship between LDA and HCM, Linear Discriminant Analysis-guided adaptive subspace hard c-means clustering algorithm (LDA-HCM) had been proposed. LDA-HCM combines LDA and HCM into a coherent framework and can adaptively reduce the dimension of data while performing data clustering simultaneously. Seeing that LDA-HCM is still a hard clustering algorithm, we consider the fuzzy extension version of LDA-HCM in this paper. To this end, firstly, we propose a new optimization criterion of Fuzzy Linear Discriminant Analysis (FLDA) by extending the value of membership function in classical LDA from binary 0 or 1 into closed interval [0, 1]. In the meantime, we present an efficient algorithm for the proposed FLDA. Secondly, we show the close relationship between FLDA and Maximum Entropy Fuzzy Clustering Algorithm (MEFCA): they both are maximizing fuzzy between-class scatter and minimizing within-class scatter simultaneously. Finally, based on the above analysis, combining FLDA and MEFCA into a joint framework, we propose fuzzy Linear Discriminant Analysis-guided maximum entropy fuzzy clustering algorithm (FLDA-MEFCA). LDA-MEFCA is a natural and effective fuzzy extension of LDA-HCM. Due to the introduction of soft decision strategy, FLDA-MEFCA can yield fuzzy partition of data set and is more flexible than LDA-HCM. We also give the convergence proof of FLDA-MEFCA. Extensive experiments on a collection of benchmark data sets are presented to show the effectiveness of the proposed algorithm.

The Computer Generated Hologram (CGH) technique is the main method for optical testing the free form surface.For testing a convex free form surface mirror, a CGH element with the surface testing, interferometer and free form mirror precise position function was designed by use of appropriative software, the testing precision was less than 0.011(=632.8nm) in RMS value by this means. (2013) Trans Tech Publications, Switzerland.

As the aperture for a monolithic mirror was limited in 1.2 m by traditional technologies,a new reaction-formed joint technology for RB-SiC was proposed.With the proprosed technology,the SiC mirror was joined in the green body process,and the green body densification and the joint of mirror were finished in the same sintering process.A 230 mm diameter RB-SiC mirror was fabricated by this technology.After milling and polishing finely with the FSJG-2 facility,the figure error of the mirror surface is less than λ/50(λ=632.8 nm).The mirror was tested in the temperature range of(20±3) ℃,and the tested results show that the change of the figure error of the mirror surface is less than λ/300,and the mirror surface figure is not changed obviously after the thermal cycle test.Moreover,the roughness of the surface near the joint line is 3.3 nm,and its microstructure is similar to that of the RB-SiC ceramic.The thermal property of welding line is matching with that of RB-SiC ceramic.Obtained results demonstrate that the reaction-formed joint technology for the RB-SiC mirror satisfies the need of the large aperture mirror used in space optics.

Because of the sic material’s superior optical characteristic, machine characteristic and hot characteristic, it becomes currently the space big aperture reflector choose firstly1. For larger aperture sic mirror, it is not economical and safe to make the monolithic body directly2,3. The SiC mirror brazed assembly with several segments can solve these problems. In this paper, one Φ600 mm sic plane mirror as demonstration welded with 3 radial segments is roughly grinded to the required figure at first, then the mirror is finely grinded and polished by the technology of CCOS, the mirror figure error is less than 1/20λ (λ = 632.8nm) in RMS finally. The problems of the preferential removal near braze joint are solved. The methods of reducing the residual stress of mirror are discussed. At last, some measurements and experiments are carried on, and the results conclude that the brazed SiC mirror can meet the requirement of large aperture optical systems

In order to test large and off-axis aspheric surfaces without the aid of other null optics,a new method subaperture stitching interferometry(SSI) is introduced.The basic principle of the technique is analysed,and the synthetical optimization stitching model and effective stitching algorithm are established based on homogeneous coordinates transformation and simultaneous least-squares method.The stitching software and prototype for testing of large aspheres by SSI are devised and developed.An off-axis asphere with the aperture of 376×188 mm2 is tested by this method.For the comparison and validation,the asphere is also tested by null compensation,the synthesized surface map is consistent to the entire surface map from the null test,and the difference of PV and RMS error between them is 0.047λ and 0.006λ,respectively.So it provides another quantitive measurement for testing large aspheric surfaces and off-axis aspheres besides null-compensation.

Discriminative clustering DC can effectively integrates subspace selection and clustering into a coherent framework. It performs in the iterative classical Linear Discriminant Analysis LDA dimensionality reduction and clustering processing. DC can effectively cluster the data with high dimension. However, it has complex form and high computational complexity. Recent work shows DC is equivalent to kernel k-means KM with a specific kernel matrix. This new insights provides a chance of simplifying the optimization problem in the original DC algorithm. Based on this equivalence relationship, Discriminative K-means DKM algorithm is proposed. When the number of data points denoted as n is small, DKM is feasible and efficient. However, the construction of kernel matrix needs to compute the inverse of a matrix in DKM, when n is large, which is time consuming. In this paper, we concentratei?źon the efficiency of DC. We present a new framework for DC, namely, Efficient DC EDC, which consists of DKM and the whitening transformation of the regularized total scatter matrix WRTS plus KM clustering WRTS+KM. When m dimensions is small and n far outweighs m, namely, ni?źi?źi?źm, EDC can carry out WRTS+KM on data, which is more efficient than DKM. When n is small and m far outweighs n, namely, mi?źi?źi?źn, EDC can carry out DKM on data, which is more efficient. We also extend EDC to soft case, and propose Efficient Discriminative Maximum Entropy Clustering EDMEC, which is an efficient version of maximum entropy based DC. Extensive experiments on a collection of benchmark data sets are presented to show the effectiveness of the proposed algorithms.

The free surface and unrotational-symmetric surface optical elements have been applied more and more widely along with the development of optical design technology, although they are still difficult for manufacturing. In this letter, a SiC unrotational-symmetric aspheric surface whose surface equation is z=3\lambda(x3+y3)(\lambda=0.6328 \mum) has been introduced. The tilt abstraction is adopted to minimize the material removal. The surface figures are peak-to-valley (PV) value of 0.327\lambda and root-mean-square (RMS) value of 0.023\lambda. A non-null testing method based on digital mask is proposed to test this surface. The accuracy of the method is testified by the experiment of standard sphere testing.

Macrophages are abundantly found in the tumor microenvironment and enhance malignancy. At distal metastatic sites, our previous studies identified a distinct population of metastasis associated macrophages (MAMs) that promotes tumor cell extravasation, seeding and persistent growth. These macrophages were derived from circulating inflammatory monocytes recruited by CCL2/CCR2 chemokine signaling and directly promote tumor cell extravasation and metastatic seeding in vivo through VEGF production. Our recent studies identified that MAMs express high levels of cell surface FMS-like tyrosine kinase 1 (FLT1, also known as VEGFR1) after their recruitment. Blockade of FLT1 signaling using specific inhibitory antibodies significantly inhibited the metastatic seeding and persistent growth. Using several genetic models of Flt1 deficiency, we show that macrophage specific FLT1 signaling is critical for breast tumor distal metastatic potential. FLT1 is not expressed by other hematopoietic cells and its inhibition did not affect the recruitment of MAMs, which indicated that specific FLT1 signaling in MAMs are important for their metastasis promoting functions. Indeed, we identified that FLT1 regulates a set of inflammatory response genes including Colony Stimulating Factor 1 (CSF1) a central regulator of macrophage biology. Using a genetic gain-of-function approach we show that CSF1 mediated autocrine signaling in MAMs is downstream of FLT1 and can restore the tumor-promoting activity in MAMs even when FLT1 has been inhibited. Together, our data established a link between inflammation and cancer metastasis and suggested the therapeutic potential of targeting these pathways in treating metastatic disease. Citation Format: Bin-Zhi Qian, Hui Zhang, Jiufeng Li, Eun-Jin Yeo, Neil O. Carragher, Anne R. Bresnick, Richard A. Lang, Jeffrey W. Pollard. Macrophage FLT1 mediated inflammatory response determines breast cancer distal metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr A13.

Freeform surfaces provide more degrees of freedom for design of optical systems, and enhance the ability of compensation and correction aberrations. Freeform surfaces are of advantage to balance the unsymmetrical aberrations, especially for the wide-field off-axis optical systems. This paper focus on an off-axis reflective optical system, which focal length is 550mm, F# is 6.5 and field of view (FOV) is 76°. The system adopts some freeform surfaces. We discuss the problems we noticed in processes of design, manufacture, measurement and alignment, and the solutions. At last, the periodical research result and the expected performance are given.

In view of local feature weighting hard C-means (LWHCM) clustering algorithm sensitive to noise, based on a non-Euclidean metric, a robust local feature weighting hard C-means (RLWHCM) clustering algorithm is presented. The robustness of RLWHCM is analyzed by using the location M-estimate in robust statistical theory. By endowing each data point with a dynamic weighting function on each feature of data point, RLWHCM can estimate the clustering center more accurately in noisy environment. Experimental results on synthetic and real world data sets demonstrate the advantages of RLWHCM over LWHCM.

For K-harmonic means(KHM) clustering algorithm and its generalized form: KHM P . clustering algorithm, fuzzy c-means clustering algorithm (FCM) and its generalized form: GFCM P clustering algorithms, the relations between KHM and FCM, KHM P and GFCM P are studied. By using the reformulation of the GFCM P , the facts that KHM P is a special case of FCM P as fuzzy parameter m is 2 and parameterp is greater than 2, and KHM is FCM as fuzzy parameter m is 2 are revealed. By using the theory of Robust Statistics, the performances of FCM P under different parameter p is studied and the conclusions are obtained: GFCM p is sensitive to noise when parameter p is greater than 1; it is robust to noise when p is less than 1. Experimental results show the correctness of our analysis.

SiC is a preferential material for space large aperture mirror at present. Aperture of 1 meter sic mirror can meet most requirements of space optical systems. For larger aperture sic mirror, it is not economical and safe to make the monolithic body directly. The SiC mirror brazed assembly with several segments can solve these problems. In this paper, one Φ600 mm sic plane mirror as demonstration welded with 3 radial segments is roughly grinded to the required figure at first, then the mirror is finely grinded and polished by CCOS technology, the RMS of the figure error is less than 1/20λ (λ = 632.8nm) finally. The problems of the preferential removal near braze joint and material removing rate influenced by deformation of mirror surface are solved. Methods of reducing the residual stress of mirror are discussed. At last, some measurements and experiments are carried on, and the results conclude that the brazed SiC mirror can meet the requirement of large aperture optical systems.

A new method combined subaperture stitching with interferometry(SSI) is introduced. It can test large and off-axis aspheric surfaces without the aid of other null optics. In this paper the basic principle and theory of the technique are analyzed. The synthetical optimization stitching model and effective stitching algorithm are established based on homogeneous coordinates transformation and simultaneous least-squares method. The software of SSI is devised and the prototype for testing of large aspheres by SSI is designed and developed. An off-axis asphere with the aperture of 376mm×188mm is tested by this method. For comparison and validation, the asphere is also tested by null compensation.The synthesized surface profile is consistent to that ofthe entire surface from null test; and the difference of PV and RMS error between them is 0.047 λ and 0.006 λ, respectively. So it provides another quantitative measurement for testing large aspheric surfaces and off-axis aspheres besides null-compensation.

In previous work, wavefront coding technology has been applied on an off-axis three mirror anastigmatic optical system. The secondary mirror is selected as the wavefront coded element. After redesigned the surface of secondary mirror becomes an unusual unrotational-symmetric surface with cubic term, which can not be tested by traditional null testing with compensator. For preparing for manufacturing and testing this kind of elements, a simple cubic surface whose equation is z=3λ(x3 + y3) (where x, y is normalized coordinate, λ=0.6328 μm) is polished. The final surface figure is 0.327λ(PV) and 0.023λ(RMS). The manufacture of this surface is introduced in this paper. The tilt component is subtracted to minimize the material removal. Also a non-null method is described for testing the experimental element. The deviation from a reference plane of the cubic surface is regarded as system error. In another words, the ideal cubic surface is set as the reference artificially. A special system error file for interferometer can be created so that the cubic term can be extracted during the testing process automatically. The residual error is just the departure from the ideal figure of the surface under machining by this way. The error and effective range is also presented. But the method may not be practical for the secondary mirror as wavefront coded element because the surface of that kind is convex asphere added cubic term. An improved non-null method is discussed for testing this kind of surface.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Sites of direct contact between a macrophage, a tumor cell and endothelial cell [Tumor MicroEnvironment of Metastasis (TMEM)], correlates with metastasis in breast cancer patients independently of other clinical prognostic indicators suggesting a direct role for TMEM function in hematogenous dissemination. Here we show, using intravital high-resolution two-photon microscopy, that tumor cell intravasation occurs only at TMEM. Tumor cell intravasation occurs concurrently with transient, local vascular permeability at TMEM in an autochthonous mouse mammary carcinoma model and a human patient-derived xenograft model. Ablation of the presence or activity of the TMEM associated macrophages blocks tumor cell intravasation at TMEM demonstrating an essential role of perivascular macrophages in TMEM function. A subset of TMEM macrophages are identified as Tie2-expressing macrophages that are characterized by F4/80+/CD11b+/CD68+/MRC1+/Tie2Hi/VEGFAHi/CD11c-. VEGFA signaling from Tie2Hi TMEM-associated macrophages causes the local loss of vascular junctions resulting in transient vascular permeability and tumor cell intravasation at TMEM. Macrophage-specific ablation of VEGFA results in increased vascular junction stability and inhibition of intravasation, demonstrating that vascular junction dissolution at VEGFAHi/Tie2Hi TMEM-associated macrophages leads to vascular permeability and tumor cell intravasation. Inhibition of Tie2 with the first in class small molecular inhibitor rebastinib impairs TMEM function leading to a reduction in vascular permeability, tumor cell dissemination and metastasis. Further, rebastinib inhibition of Tie2 blocks tumor cell extravasation and metastatic growth in the lungs. Together, the findings that TMEM macrophages mediate vascular permeability and tumor cell intravasation demonstrate an essential role for TMEM within the primary mammary tumor as sites of tumor cell dissemination. These data reveal the mechanism of tumor cell intravasation in breast cancer, explain the prognostic value of TMEM density in predicting distant metastatic recurrence in breast cancer patients and document a strategy for inhibition of dissemination. This research is supported by the Department of Defense Breast Cancer Research Program under award number BC120227 (ASH), NIH CA100324 (JSC) and the Integrated Imaging Program. Citation Format: Allison S. Harney, Esther N. Arwert, David Entenberg, Yarong Wang, Peng Guo, Bin-Zhi Qian, Bryan D. Smith, Jeffrey W. Pollard, Joan G. Jones, Daniel L. Flynn, John S. Condeelis. Imaging the tumor microenvironment of metastasis reveals the mechanism of transient blood vessel permeability and tumor cell intravasation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5125. doi:10.1158/1538-7445.AM2015-5125

Macrophages are abundantly found in the tumor microenvironment enhance malignancy. At distal metastatic sites a distinct population of metastasis associated macrophages (MAMs) promotes tumor cell extravasation, seeding and persistent growth. Compared with lung resident macrophages, MAMs associated with breast cancer lung metastasis in pre-clinical models express high levels of cell surface FMS-like tyrosine kinase 1 (Flt1). Blockade of FLT1 signaling using specific inhibitory antibodies significantly inhibited the metastatic seeding and persistent growth of both human and murine breast tumor cell. This was confirmed using a genetic model of Flt1 tyrosine kinase domain (TK) ablation. Using bone marrow transplantation techniques, we further showed that this metastasis inhibitory effect was due to the lack of FLT1 signaling in hematopoietic cells. Furthermore, macrophage specific ablation of the tyrosine kinase domain of Flt1 by crossing Flt1 flox/flox mice with macrophage restricted Cre mice (Csf1r-Cre) also significantly inhibited tumor cell metastatic potential. Since Flt1 is not expressed by other hematopoietic cells and FLT1 inhibition did not affect the recruitment of MAMs, it indicated that specific FLT1 signaling in MAMs are important for their metastasis promoting functions. FLT1 regulated genes were identified by comparing gene expression profiles using microarray techniques of FACS sorted MAMs from mice treated with control and anti-FLT1 inhibitory antibody. Bioinformatics analysis showed that inflammatory response genes were highly enriched in these genes. Together, our studies indicated that FLT1 signaling is required for the activation of metastasis associated macrophages and regulates a set of inflammatory genes that promote breast tumor distal metastasis. Citation Format: Bin-Zhi Qian, Richard A. Lang, Jeffrey W. Pollard. Macrophage FLT1 signaling activates an inflammatory response that promotes breast cancer distal metastasis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1531. doi:10.1158/1538-7445.AM2013-1531

Recent studies on breast cancer lung metastasis have identified a new mechanism of tumor cell survival via signaling provided by metastasis-associated macrophages. Targeting these specialized host immune cells and their specific signals provides an attractive and potential therapeutic approach for treating the disease.

The tumor microenvironment represents a complex and changing ecology of many different cell types whose interactions determines the overall malignancy of the tumor. This environment consists of tumor cells harboring oncogenic and tumor suppressor mutations together with normal cells that include resident ones and those recruited from the bone marrow. In this latter class myeloid cells and especially macrophages, the subject of our studies, are particularly well represented. Associative clinical studies have indicated that the abundance of macrophages or overexpression of their signaling pathways is often an indicator of poor prognosis in a wide variety of cancers. These data suggests a pro-tumoral role for tumor-associated macrophages. This hypothesis that macrophages promoted malignancy is supported by a significant number of studies using genetic or pharmacological ablation of macrophages or their signaling pathways. In our studies, we used genetic ablation of macrophages in the model of breast cancer caused by the mammary epithelial expression of the Polyoma Middle T oncoprotein (PyMT). This ablation resulted in a slowing of tumor progression to malignancy and an inhibition of metastasis. We and our collaborators have identified several traits that macrophages confer in the primary tumor that account for their enhancement of malignancy. These are in the promotion of angiogenesis, stimulation of tumor cell invasion, migration and intravasation. At the metastatic site we have also shown that macrophages promote tumor cell extravasation and subsequent growth. Macrophage isolation and characterization from PyMT tumors and their metastatic sites suggest that each of these activities is regulated by a distinct subsets of macrophages that nevertheless express canonical macrophage markers. Each of these macrophage populations have defining cell surface markers and unique transcriptional profiles that suggest individual functions (Condeelis and Pollard, 2006; Qian and Pollard, 2010). Metastasis is the major cause of the failure of therapy and therefore death in cancer patients. Therefore we have focused our recent research on this process. We showed that macrophages are rapidly recruited to tumor cells as they metastasize to the lung. Ablation of these metastasis-associated macrophages (MAMs) using either genetic or pharmacological means results in an inhibition of tumor cell seeding and subsequent growth. Importantly ablation of these macrophages after the tumor cells have become established also inhibited subsequent metastatic growth suggesting that these cells represent therapeutic targets. Using ex vivo imaging methods we showed that a major action of these macrophages was on the promotion of tumor cell extravasation with subsequent effects on viability. This effect of macrophage on tumor cells could be recapitulated in an ex vivo extravasation assay thus enabling the interrogation of specific signaling molecules that may have function in promoting extravasation. To analyze the source of these MAMs, we performed adoptive transfers of the two different populations of monocytes that are defined by the presence or absence of the surface antigen Ly6C. Interestingly there was preferential recruitment of the Ly6C+ population to the metastatic sites whether in an experimental model of metastasis or into spontaneous metastases from PyMT tumors. Tracking of these monocytes showed that they rapidly differentiated into MAMs in the lung. A similar monocytic population (CD14+CD16-) circulating in human peripheral blood was recruited to human breast cancer metastases following adoptive transfer into immunocompromised mice. Furthermore, in mice we found that the Ly6C+ monocytes are preferentially recruited to bone metastases. In contrast to these data, Ly6C negative monocytes are recruited to the spontaneous tumors and to liver metastases there is a reduction in the recruitment of both populations of monocytes. Inhibition of the recruitment of these Ly6C+ monocytes inhibited tumor cell extravasation and thus metastases in bone and lung but not liver. These data suggest that alternative and tissue-specific mechanisms are operative at different metastatic sites. The dynamic acquisition of monocytic populations to primary and metastatic tumors and their differentiation into distinct macrophage populations represents the potential to target aspects of the tumor microenvironment. Such novel therapeutics in combination with conventional chemotherapeutic and/or radiation therapy may provide synergistic benefits to the patient. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr PL03-01. doi:10.1158/1538-7445.AM2011-PL03-01

Macrophages are abundant in the tumor microenvironment and enhance malignancy through their promotion of angiogenesis and invasion at the primary tumor site as well as extravasation, target organ seeding and persistent growth at distant metastatic sites. To determine the origin and recruitment of tumor associated macrophages, different populations of monocytes were FACS sorted and adoptively transferred into mice bearing MMTV-PyMT induced mouse mammary tumors with or without spontaneous pulmonary metastases. Ly6C+ inflammatory monocytes were preferentially recruited to pulmonary metastases but not primary tumors in a CCL2 (also known as MCP1) dependent manner. Human inflammatory monocytes were also preferentially recruited to pulmonary metastases of human breast cancer cells in immuno-compromised mice in a CCL2 dependent manner. These inflammatory monocytes promote tumor cell trans-endothelial migration in vitro, a process that is abrogated by an anti-CCL2 neutralizing antibody. Neutralizing CCL2 in vivo blocks the recruitment of metastasis associated macrophages and their direct interaction with metastasizing tumor cells, leading to inhibition of tumor cell extravasation and metastatic seeding. Inhibition of tumor cell-derived CCL2 inhibits their metastatic seeding. Secretory factors from inflammatory monocytes were identified to mediate their metastasis-promoting function in vitro and in vivo. Both CCL2 expression and macrophage infiltration are correlated with poor prognosis in human breast cancer. Our data strongly suggest that recruitment of Ly6C+ inflammatory monocytes is the mechanistic link between these two clinical associations and suggests new therapeutic targets for treating metastatic breast disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2842. doi:10.1158/1538-7445.AM2011-2842