Project description:Clinical and experimental evidence indicates that tumor-associated macrophages (TAMs) promote malignant progression. In breast cancer, TAMs enhance tumor angiogenesis, tumor cell invasion, matrix remodeling, and immune suppression against the tumor. In this study, we examined late-stage mammary tumors from a transgenic mouse model of breast cancer. We used flow cytometry under conditions that minimized gene expression changes to isolate a rigorously defined TAM population previously shown to be associated with invasive carcinoma cells. The gene expression signature of this population was compared with a similar population derived from spleens of non-tumor-bearing mice using high-density oligonucleotide arrays. Using stringent selection criteria, transcript abundance of 460 genes was shown to be differentially regulated between the two populations. Bioinformatic analyses of known functions of these genes indicated that formerly ascribed TAM functions, including suppression of immune activation and matrix remodeling, as well as multiple mediators of tumor angiogenesis, were elevated in TAMs. Further bioinformatic analyses confirmed that a pure and valid TAM gene expression signature in mouse tumors could be used to assess expression of TAMs in human breast cancer. The data derived from these more physiologically relevant autochthonous tumors compared with previous studies in tumor xenografts suggest tactics by which TAMs may regulate tumor angiogenesis and thus provide a basis for exploring other transcriptional mediators of TAM trophic functions within the tumor microenvironment. Tumor-associated macrophages from late-stage mouse mammary tumors compared to splenic macrophages from non-tumor-bearing littermate controls. 4 biological replicates of each population were compared via gene expression arrays.
Project description:Macrophage infiltration is a hallmark of solid cancers and overall macrophage infiltration correlates with lower patient survival and resistance to therapy. Tumor- associated macrophages, however, are phenotypically and functionally heterogeneous. Specific subsets of tumor-associated macrophage might be endowed with antagonistic roles on cancer progression and on the development of anti-tumor immunity. Here, we identify a discrete population of FOLR2 + tissue-resident macrophages in healthy mammary gland and breast cancer primary tumors. FOLR2 + macrophages localize in perivascular areas in the tumor stroma, where they interact with CD8 + T cells. Moreover, FOLR2 + macrophages efficiently prime effector CD8 + T cells ex vivo . The density of FOLR2 + macrophages in tumors positively correlates with better patient survival. This study highlights antagonistic roles for tumor-associated macrophage subsets and paves the way for subset-specific therapeutic interventions in macrophages-based cancer therapies.
Project description:Macrophages have been implicated in breast cancer progression and metastasis, but relatively little is known about the genes and pathways that are involved. Using a conditional allele of Ets2 in the mouse, we have identified Ets2 as a critical gene in tumor associated macrophages (TAMs) that specifically promotes mammary tumor metastasis. Loss of Ets2 in TAMs decreased the frequency and size of lung metastases without impacting primary tumor burden. Expression profiling of isolated tumor macrophages established that Ets2 deficiency resulted in the de-repression of a defined set of anti-angiogenic genes. Activation of this transcriptional program correlated with decreased angiogenesis in metastatic tumors and decreased metastatic growth. Comparison of this Ets2-specific TAM expression profile with human breast cancer profiles revealed a macrophage gene expression signature that could predict overall survival of estrogen receptor negative patients. In summary, we have identified a critical factor, Ets2, in TAMs that represses a transcriptional program to promote the growth of mammary tumor metastases in the lung. Breast TAMs were isolated from early-stage PyMT-induced mammary tumors expressing Ets2 and also from the tumors with Ets2-deficient TAMs. Since macrophages have also been implicated in normal mammary gland remodeling, normal remeodeling macrophages were also purified from females expressing Ets2 and the ones where Ets2 is deleted in the macrophages. One RNA sample was extracted from each genetic group for gene-expression profiling.
Project description:The aim of this investigation was to study the consequences of interfering with soluble epoxide hydrolase (sEH) expression on tumor growth and metastasis in genetically modified animals that spontaneously generate tumors without the exogenous application of high concentrations of epoxide mediators or inhibitors. Therefore, breast cancer development was studied in mice expressing the polyoma middle T oncogene (PyMT) under the control of the mouse mammary tumor virus promoter, to induce spontaneous mammary tumors. To facilitate the study of endogenous sEH activity in tumor growth, PyMT mice were then crossed with sEH-/- mice to generate sEH-deficient mice that spontaneously generate breast tumors (so called PyMTsEH mice). For these analyses, primary tumors were removed from 20 week old mice.
Project description:Clinical and experimental evidence indicates that tumor-associated macrophages (TAMs) promote malignant progression. In breast cancer, TAMs enhance tumor angiogenesis, tumor cell invasion, matrix remodeling, and immune suppression against the tumor. In this study, we examined late-stage mammary tumors from a transgenic mouse model of breast cancer. We used flow cytometry under conditions that minimized gene expression changes to isolate a rigorously defined TAM population previously shown to be associated with invasive carcinoma cells. The gene expression signature of this population was compared with a similar population derived from spleens of non-tumor-bearing mice using high-density oligonucleotide arrays. Using stringent selection criteria, transcript abundance of 460 genes was shown to be differentially regulated between the two populations. Bioinformatic analyses of known functions of these genes indicated that formerly ascribed TAM functions, including suppression of immune activation and matrix remodeling, as well as multiple mediators of tumor angiogenesis, were elevated in TAMs. Further bioinformatic analyses confirmed that a pure and valid TAM gene expression signature in mouse tumors could be used to assess expression of TAMs in human breast cancer. The data derived from these more physiologically relevant autochthonous tumors compared with previous studies in tumor xenografts suggest tactics by which TAMs may regulate tumor angiogenesis and thus provide a basis for exploring other transcriptional mediators of TAM trophic functions within the tumor microenvironment.
Project description:To facilitate analysis of protein expression changes in in situ tumors and stroma, we took advantage of a mouse model that permits conditional activation of the Ser-Thr kinase ROCK within mammary tumor cells. In this study, we undertook MALDI-MSI analysis of tissue samples derived from our conditional ROCK mammary tumor model, to quantify in an unbiased manner, the proteomic changes occurring during the progression of mammary cancers in their specific spatial contexts.
Project description:Tumor-associated myeloid cells play a pivotal role in the regulation of processes that control tumor growth and metastasis, and their accumulation in tumors is an established negative prognostic factor in breast cancer. Here, we show that inhibition of calcium/calmodulin-dependentkinase kinase 2 (CaMKK2) expression within myeloid cells inhibits tumor growth in mouse models of mammary cancer. This activity is associated with the accumulation of macrophages within the tumor microenvironment that express high levels of the major histocompatibility molecule class II molecule I-A (MHC II I-A), and granzyme positive CD8+T-cells. Treatment with specific CaMKK2 inhibitors block tumor growth, in a CD8+ T-cell dependent manner, and facilitates favorable reprogramming of the immune cell microenvironment. CaMKK2 protein expression was highest in the most aggressive subtypes of human breast cancer and, in the most malignant tumors, both tumor cells and tumor-associated macrophages express high levels of this enzyme. In aggregate, these findings implicate CaMKK2 as a macrophage-selective immune checkpoint, the inhibition of which may have utility in the immunotherapy of breast cancer.
Project description:Stabilin-1 is a scavenger/sorting receptor expressed by sinusoidal endothelial cells, alternatively-activated and tumor-associated macrophages (TAM) in several types of human cancer and mouse tumor models. We have found abundant expression of stabilin-1 on TAM in mouse model of mammary adenocarcinoma (TS/A) We performed microarrays with TAM isolated from wild type (wt) and stabilin-1 knock out (ko) mice in order to examine if stabilin-1 affects gene expression in TAM using mouse model of TS/A mammary adenocarcinoma Balb/c Wt and stabilin-1 ko female mice (8-12 weeks old) were inoculated s.c. with 5x10e6 TS/A cells. TAM were isolated from TS/A tumors 21 days after tumor challenge using CD11b MACS beads (Miltenyi Biotec), lysed for RNA and used for microarrays. Samples from 3 wt and 3 stabilin-1 ko mice were analyzed.
Project description:Macrophages are diverse immune cells that reside in all tissues to regulate development, function and homeostasis. In the mammary gland, a highly dynamic organ that undergoes dramatic remodeling throughout life, macrophages have been implicated in development and breast tumorigenesis. Ductal macrophages, as opposed to their stromal counterparts, were found to promote ductal morphogenesis during puberty and efficiently phagocytose alveolar cells post-lactation. Within mammary tumors, only ductal macrophages expanded to form a network throughout the tumor, where they also contact intra-tumoral T cells. Furthermore, ductal macrophages accelerated the growth of tumor organoids. Thus, pro-remodeling mammary ductal macrophages represent the normal tissue counterpart of tumor macrophages in an organ that is highly susceptible to oncogenesis. To gain insight into ductal macrophage function, we sorted all antigen presenting cell populations from mouse mammary glands and undertook RNA-seq expression profiling. This showed that ductal macrophages have a distinct expression profile from those of stromal macrophages or dendritic cells from the mammary gland. Results from this data series are presented in Figure 2 of Dawson et al (2020).
Project description:The objective of this study was to determine the effect of Thyroid Hormone Responsive Protein Spot14 (Spot14) loss on the gene expression profiles of tumors from MMTV-Polyomavirus middle-T antigen (PyMT) mice. MMTV-PyMT/S14-heterozygous mice were crossed with S14-heterozygous mice and 1 cm tumors from MMTV-PyMT control (wild-type S14) or MMTV-PyMT/S14-null offspring were profiled using Affymetrix gene arrays. Tumor latency was not different between groups; however, tumors lacking S14 grew significantly slower than control tumors. Loss of S14 also decreased the levels of de novo synthesized fatty acids in mammary tumors. In additional studies, performed on MMTV-Neu mice, we found that S14 overexpression was associated with increased tumor cell proliferation and elevated levels of tumor fatty acids. Gene expression profiling revealed that S14 loss and overexpression in mouse mammary tumors altered pathways associated with proliferation and metabolism. This study provides important information about the role of S14 in mammary tumorigenesis and tumor metabolism. Microarray analysis was performed on 4 mammary tumors from MMTV-PyMT mice and 4 tumors from MMTV-PyMT/S14-null mice.