Cancer metastasis linked to macrophage size, shape, and metabolism

Single-cell RNA profiling reveals classification and characteristics of mononuclear phagocytes in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer mortality and a serious health problem worldwide. Mononuclear phagocytes are the main immune cells in the tumor microenvironment of CRC with remarkable plasticity, and current studies show that macrophages are closely related to tumor progression, invasion and dissemination. To understand the immunological function of mononuclear phagocytes comprehensively and deeply, we use single-cell RNA sequencing and classify mononuclear phagocytes in CRC into 6 different subsets, and characterize the heterogeneity of each subset. We find that tissue inhibitor of metalloproteinases (TIMPs) involved in the differentiation of proinflammatory and anti-inflammatory mononuclear phagocytes. Trajectory of circulating monocytes differentiation into tumor-associated macrophages (TAMs) and the dynamic changes at levels of transcription factor (TF) regulons during differentiation were revealed. We also find that C5 subset, characterized by activation of lipid metabolism, is in the terminal state of differentiation, and that the abundance of C5 subset is negatively correlated with CRC patients' prognosis. Our findings advance the understanding of circulating monocytes' differentiation into macrophages, identify a new subset associated with CRC prognosis, and reveal a set of TF regulons regulating mononuclear phagocytes differentiation, which are expected to be potential therapeutic targets for reversing immunosuppressive tumor microenvironment.

Macrophage-, Dendritic-, Smooth Muscle-, Endothelium-, and Stem Cells-Derived Foam Cells in Atherosclerosis

Atherosclerosis is an inflammatory disease depending on the buildup, called plaque, of lipoproteins, cholesterol, extracellular matrix elements, and various types of immune and non-immune cells on the artery walls. Plaque development and growth lead to the narrowing of the blood vessel lumen, blocking blood flow, and eventually may lead to plaque burst and a blood clot. The prominent cellular components of atherosclerotic plaque are the foam cells, which, by trying to remove lipoprotein and cholesterol surplus, also participate in plaque development and rupture. Although the common knowledge is that the foam cells derive from macrophages, studies of the last decade clearly showed that macrophages are not the only cells able to form foam cells in atherosclerotic plaque. These findings give a new perspective on atherosclerotic plaque formation and composition and define new targets for anti-foam cell therapies for atherosclerosis prevention. This review gives a concise description of foam cells of different pedigrees and describes the main mechanisms participating in their formation and function.

HMOX1 promotes lung adenocarcinoma metastasis by affecting macrophages and mitochondrion complexes

Background

Metastasis is the leading cause of lung adenocarcinoma (LUAD) patient death. However, the mechanism of metastasis is unclear. We performed bioinformatic analyses for HMOX1 (Heme oxygenase-1), aiming to explore its role in LUAD metastasis.

Methods

Pan-cancer analysis was first used to identify the metastasis-associated role of HMOX1 in LUAD. HMOX1-related genomic alterations were then investigated. Based on functional enrichment, we systematically correlated HMOX1 with immunological characteristics and mitochondrial activities. Furthermore, weighted gene co-expression network analysis (WGCNA) was applied to construct the HMOX1-mediated metastasis regulatory network, which was then validated at the proteomic level. Finally, we conducted the survival analysis and predicted the potential drugs to target the HMOX1 network.

Results

HMOX1 expression was significantly associated with epithelial-mesenchymal transition (EMT) and lymph and distant metastasis in LUAD. High HMOX1 levels exhibited higher macrophage infiltration and lower mitochondrial complex expression. WGCNA showed a group of module genes co-regulating the traits mentioned above. Subsequently, we constructed an HMOX1-mediated macrophage-mitochondrion-EMT metastasis regulatory network in LUAD. The network had a high inner correlation at the proteomic level and efficiently predicted prognosis. Finally, we predicted 9 potential drugs targeting HMOX1-mediated metastasis in LUAD, like chloroxine and isoliquiritigenin.

Conclusions

Our analysis elaborates on the role of HMOX1 in LUAD metastasis and identified a highly prognostic HMOX1-mediated metastasis regulatory network. Novel potential drugs targeting the HMOX1 network were also proposed, which should be tested for their activity against LUAD metastasis in future studies.