p53 deficient breast cancer cells reprogram preadipocytes toward tumor-protective immunomodulatory cells.

The gene is mutated in approximately 30% of all breast cancer cases. Adipocytes and preadipocytes, which constitute a substantial fraction of the stroma of normal mammary tissue and breast tumors, undergo transcriptional, metabolic, and phenotypic reprogramming during breast cancer development and play an important role in tumor progression. We report here that p53 loss in breast cancer cells facilitates the reprogramming of preadipocytes, inducing them to acquire a unique transcriptional and metabolic program that combines impaired adipocytic differentiation with augmented cytokine expression.

Neoadjuvant immune checkpoint blockade triggers persistent and systemic T activation which blunts therapeutic efficacy against metastatic spread of breast tumors.

The clinical successes of immune checkpoint blockade (ICB) in advanced cancer patients have recently spurred the clinical implementation of ICB in the neoadjuvant and perioperative setting. However, how neoadjuvant ICB therapy affects the systemic immune landscape and metastatic spread remains to be established. Tumors promote both local and systemic expansion of regulatory T cells (T), which are key orchestrators of tumor-induced immunosuppression, contributing to immune evasion, tumor progression and metastasis.

scChIX-seq infers dynamic relationships between histone modifications in single cells.

Regulation of chromatin states involves the dynamic interplay between different histone modifications to control gene expression. Recent advances have enabled mapping of histone marks in single cells, but most methods are constrained to profile only one histone mark per cell. Here, we present an integrated experimental and computational framework, scChIX-seq (single-cell chromatin immunocleavage and unmixing sequencing), to map several histone marks in single cells.

MYC promotes immune-suppression in triple-negative breast cancer via inhibition of interferon signaling.

The limited efficacy of immune checkpoint inhibitor treatment in triple-negative breast cancer (TNBC) patients is attributed to sparse or unresponsive tumor-infiltrating lymphocytes, but the mechanisms that lead to a therapy resistant tumor immune microenvironment are incompletely known. Here we show a strong correlation between MYC expression and loss of immune signatures in human TNBC. In mouse models of TNBC proficient or deficient of breast cancer type 1 susceptibility gene (BRCA1), MYC overexpression dramatically decreases lymphocyte infiltration in tumors, along with immune signature remodelling.

Tumor-associated macrophages promote intratumoral conversion of conventional CD4 T cells into regulatory T cells via PD-1 signalling.

While regulatory T cells (T) and macrophages have been recognized as key orchestrators of cancer-associated immunosuppression, their cellular crosstalk within tumors has been poorly characterized. Here, using spontaneous models for breast cancer, we demonstrate that tumor-associated macrophages (TAMs) contribute to the intratumoral accumulation of T by promoting the conversion of conventional CD4 T cells (T) into T. Mechanistically, two processes were identified that independently contribute to this process.

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.

Glucocorticoid receptor triggers a reversible drug-tolerant dormancy state with acquired therapeutic vulnerabilities in lung cancer.

The glucocorticoid receptor (GR) regulates gene expression, governing aspects of homeostasis, but is also involved in cancer. Pharmacological GR activation is frequently used to alleviate therapy-related side-effects. While prior studies have shown GR activation might also have anti-proliferative action on tumours, the underpinnings of glucocorticoid action and its direct effectors in non-lymphoid solid cancers remain elusive.

In vitro assessment of cancer cell-induced polarization of macrophages.

The progression of cancer is strongly influenced by the crosstalk between cancer cells and immune cells. Immune cells can have both pro- and anti-tumor functions depending on the signals present in the environment. A significant proportion of the immune compartment of most solid tumors consists of tumor-associated macrophages.

Loss of p53 triggers WNT-dependent systemic inflammation to drive breast cancer metastasis.

Cancer-associated systemic inflammation is strongly linked to poor disease outcome in patients with cancer. For most human epithelial tumour types, high systemic neutrophil-to-lymphocyte ratios are associated with poor overall survival, and experimental studies have demonstrated a causal relationship between neutrophils and metastasis. However, the cancer-cell-intrinsic mechanisms that dictate the substantial heterogeneity in systemic neutrophilic inflammation between tumour-bearing hosts are largely unresolved.

Fatty Acids Corrupt Neutrophils in Cancer.

Understanding how tumors escape from immune attack may offer novel therapeutic opportunities. Veglia et al. (2019) demonstrate in Nature that fatty acid transport protein 2 (FATP2) endows neutrophils with immunosuppressive capabilities that promote cancer growth.

Cancer-Cell-Intrinsic Mechanisms Shaping the Tumor Immune Landscape.

Owing to their tremendous diversity and plasticity, immune cells exert multifaceted functions in tumor-bearing hosts, ranging from anti-tumor to pro-tumor activities. Tumor immune landscapes differ greatly between and within cancer types. Emerging evidence suggests that genetic aberrations in cancer cells dictate the immune contexture of tumors.

Mammary tumor-derived CCL2 enhances pro-metastatic systemic inflammation through upregulation of IL1β in tumor-associated macrophages.

Patients with primary solid malignancies frequently exhibit signs of systemic inflammation. Notably, elevated levels of neutrophils and their associated soluble mediators are regularly observed in cancer patients, and correlate with reduced survival and increased metastasis formation. Recently, we demonstrated a mechanistic link between mammary tumor-induced IL17-producing γδ T cells, systemic expansion of immunosuppressive neutrophils and metastasis formation in a genetically engineered mouse model for invasive breast cancer.

Neutrophils in cancer: neutral no more.

Neutrophils are indispensable antagonists of microbial infection and facilitators of wound healing. In the cancer setting, a newfound appreciation for neutrophils has come into view. The traditionally held belief that neutrophils are inert bystanders is being challenged by the recent literature.