Mechanisms driving the immunoregulatory function of cancer cells.

Tumours display an astonishing variation in the spatial distribution, composition and activation state of immune cells, which impacts their progression and response to immunotherapy. Shedding light on the mechanisms that govern the diversity and function of immune cells in the tumour microenvironment will pave the way for the development of more tailored immunomodulatory strategies for the benefit of patients with cancer. Cancer cells, by virtue of their paracrine and juxtacrine communication mechanisms, are key contributors to intertumour heterogeneity in immune contextures.

Tumor-educated T drive organ-specific metastasis in breast cancer by impairing NK cells in the lymph node niche.

Breast cancer is accompanied by systemic immunosuppression, which facilitates metastasis formation, but how this shapes organotropism of metastasis is poorly understood. Here, we investigate the impact of mammary tumorigenesis on regulatory T cells (T) in distant organs and how this affects multi-organ metastatic disease. Using a preclinical mouse mammary tumor model that recapitulates human metastatic breast cancer, we observe systemic accumulation of activated, highly immunosuppressive T during primary tumor growth.

Impairment of a distinct cancer-associated fibroblast population limits tumour growth and metastasis.

Profiling studies have revealed considerable phenotypic heterogeneity in cancer-associated fibroblasts (CAFs) present within the tumour microenvironment, however, functional characterisation of different CAF subsets is hampered by the lack of specific markers defining these populations. Here we show that genetic deletion of the Endo180 (MRC2) receptor, predominantly expressed by a population of matrix-remodelling CAFs, profoundly limits tumour growth and metastasis; effects that can be recapitulated in 3D co-culture assays. This impairment results from a CAF-intrinsic contractility defect and reduced CAF viability, which coupled with the lack of phenotype in the normal mouse, demonstrates that upregulated Endo180 expression by a specific, potentially targetable CAF subset is required to generate a supportive tumour microenvironment.

Metabolic Fingerprinting Links Oncogenic PIK3CA with Enhanced Arachidonic Acid-Derived Eicosanoids.

Oncogenic transformation is associated with profound changes in cellular metabolism, but whether tracking these can improve disease stratification or influence therapy decision-making is largely unknown. Using the iKnife to sample the aerosol of cauterized specimens, we demonstrate a new mode of real-time diagnosis, coupling metabolic phenotype to mutant PIK3CA genotype. Oncogenic PIK3CA results in an increase in arachidonic acid and a concomitant overproduction of eicosanoids, acting to promote cell proliferation beyond a cell-autonomous manner.

Metabolic adaptability in metastatic breast cancer by AKR1B10-dependent balancing of glycolysis and fatty acid oxidation.

The different stages of the metastatic cascade present distinct metabolic challenges to tumour cells and an altered tumour metabolism associated with successful metastatic colonisation provides a therapeutic vulnerability in disseminated disease. We identify the aldo-keto reductase AKR1B10 as a metastasis enhancer that has little impact on primary tumour growth or dissemination but promotes effective tumour growth in secondary sites and, in human disease, is associated with an increased risk of distant metastatic relapse. AKR1B10 tumour cells have reduced glycolytic capacity and dependency on glucose as fuel source but increased utilisation of fatty acid oxidation.

Using an in-vivo syngeneic spontaneous metastasis model identifies ID2 as a promoter of breast cancer colonisation in the brain.

Background: Dissemination of breast cancers to the brain is associated with poor patient outcome and limited therapeutic options. In this study we sought to identify novel regulators of brain metastasis by profiling mouse mammary carcinoma cells spontaneously metastasising from the primary tumour in an immunocompetent syngeneic host.

Methods: 4T1 mouse mammary carcinoma sublines derived from primary tumours and spontaneous brain and lung metastases in BALB/c mice were subject to genome-wide expression profiling.

Generation and characterisation of two D2A1 mammary cancer sublines to model spontaneous and experimental metastasis in a syngeneic BALB/c host.

Studying the complex mechanisms underlying breast cancer metastasis and therapy response necessitates relevant models, particularly syngeneic models with an intact immune system. Two syngeneic spontaneously metastatic sublines, D2A1-m1 and D2A1-m2, were generated from the poorly metastasising BALB/c-derived D2A1 cell line by serial passaging. and analyses revealed distinct and shared characteristics of the metastatic D2A1-m1 and D2A1-m2 sublines.

An Functional Screen Identifies JNK Signaling As a Modulator of Chemotherapeutic Response in Breast Cancer.

Chemotherapy remains the mainstay of treatment for advanced breast cancer; however, resistance is an inevitable event for the majority of patients with metastatic disease. Moreover, there is little information available to guide stratification of first-line chemotherapy, crucial given the common development of multidrug resistance. Here, we describe an screen to interrogate the response to anthracycline-based chemotherapy in a syngeneic metastatic breast cancer model and identify JNK signaling as a key modulator of chemotherapy response.

Phosphoproteomic analysis of interacting tumor and endothelial cells identifies regulatory mechanisms of transendothelial migration.

The exit of metastasizing tumor cells from the vasculature, extravasation, is regulated by their dynamic interactions with the endothelial cells that line the internal surface of vessels. To elucidate signals controlling tumor cell adhesion to the endothelium and subsequent transendothelial migration, we performed phosphoproteomic analysis to map cell-specific changes in protein phosphorylation that were triggered by contact between metastatic MDA-MB-231 breast cancer cells and endothelial cells. From the 2669 unique phosphorylation sites identified, 77 and 43 were differentially phosphorylated in the tumor cells and endothelial cells, respectively.

An in vivo functional screen identifies ST6GalNAc2 sialyltransferase as a breast cancer metastasis suppressor.

To interrogate the complex mechanisms involved in the later stages of cancer metastasis, we designed a functional in vivo RNA interference (RNAi) screen combined with next-generation sequencing. Using this approach, we identified the sialyltransferase ST6GalNAc2 as a novel breast cancer metastasis suppressor. Mechanistically, ST6GalNAc2 silencing alters the profile of O-glycans on the tumor cell surface, facilitating binding of the soluble lectin galectin-3.

Synthetic lethality of PARP and NAMPT inhibition in triple-negative breast cancer cells.

PARP inhibitors have been proposed as a potential targeted therapy for patients with triple-negative (ER-, PR-, HER2-negative) breast cancers. However, it is as yet unclear as to whether single agent or combination therapy using PARP inhibitors would be most beneficial. To better understand the mechanisms that determine the response to PARP inhibitors, we investigated whether enzymes involved in metabolism of the PARP substrate, β-NAD(+) , might alter the response to a clinical PARP inhibitor.

Contrasting effects of sunitinib within in vivo models of metastasis.

Sunitinib is a potent and clinically approved tyrosine kinase inhibitor that can suppress tumour growth by inhibiting angiogenesis. However, conflicting data exist regarding the effects of this drug on the growth of metastases in preclinical models. Here we use 4T1 and RENCA tumour cells, which both form lung metastases in Balb/c mice, to re-address the effects of sunitinib on the progression of metastatic disease in mice.

Pericytes promote selective vessel regression to regulate vascular patterning.

Blood vessel networks form in a 2-step process of sprouting angiogenesis followed by selective branch regression and stabilization of remaining vessels. Pericytes are known to function in stabilizing blood vessels, but their role in vascular sprouting and selective vessel regression is poorly understood. The endosialin (CD248) receptor is expressed by pericytes associated with newly forming but not stable quiescent vessels.