Acetyl-CoA metabolic accumulation promotes hepatocellular carcinoma metastasis via enhancing CXCL1-dependent infiltration of tumor-associated neutrophils.

High levels of acetyl-CoA are considered a key metabolic feature of metastatic cancers. However, the impacts of acetyl-CoA metabolic accumulation on cancer microenvironment remodeling are poorly understood. In this study, using human hepatocellular carcinoma (HCC) tissues and orthotopic xenograft models, we found a close association between high acetyl-CoA levels in HCCs, increased infiltration of tumor-associated neutrophils (TANs) in the cancer microenvironment and HCC metastasis. Cytokine microarray and enzyme-linked immunosorbent assays (ELISA) revealed the crucial role of the chemokine (C-X-C motif) ligand 1(CXCL1). Mechanistically, acetyl-CoA accumulation induces H3 acetylation-dependent upregulation of CXCL1 gene expression. CXCL1 recruits TANs, leads to neutrophil extracellular traps (NETs) formation and promotes HCC metastasis. Collectively, our work linked the accumulation of acetyl-CoA in HCC cells and TANs infiltration, and revealed that the CXCL1-CXC receptor 2 (CXCR2)-TANs-NETs axis is a potential target for HCCs with high acetyl-CoA levels.

Organ-specific cholesterol metabolic aberration fuels liver metastasis of colorectal cancer.

Rationale: Metastasis, the development of secondary malignant growth at a distance from a primary tumor, is the main cause of cancer-associated death. However, little is known about how metastatic cancer cells adapt to and colonize in the new organ environment. Here we sought to investigate the functional mechanism of cholesterol metabolic aberration in colorectal carcinoma (CRC) liver metastasis. Methods: The expression of cholesterol metabolism-related genes in primary colorectal tumors (PT) and paired liver metastases (LM) were examined by RT-PCR. The role of SREBP2-dependent cholesterol biosynthesis pathway in cell growth and CRC liver metastasis were determined by SREBP2 silencing in CRC cell lines and experimental metastasis models including, intra-splenic injection models and liver orthotropic injection model. Growth factors treatment and co-culture experiment were performed to reveal the mechanism underlying the up-regulation of SREBP2 in CRC liver metastases. The in vivo efficacy of inhibition of cholesterol biosynthesis pathway by betulin or simvastatin were evaluated in experimental metastasis models. Results: In the present study, we identify a colorectal cancer (CRC) liver metastasis-specific cholesterol metabolic pathway involving the activation of SREBP2-dependent cholesterol biosynthesis, which is required for the colonization and growth of metastatic CRC cells in the liver. Inhibiting this cholesterol biosynthesis pathway suppresses CRC liver metastasis. Mechanically, hepatocyte growth factor (HGF) from liver environment activates SREBP2-dependent cholesterol biosynthesis pathway by activating c-Met/PI3K/AKT/mTOR axis in CRC cells. Conclusion: Our findings support the notion that CRC liver metastases show a specific cholesterol metabolic aberration. Targeting this cholesterol biosynthesis pathway could be a promising treatment for CRC liver metastasis.

miR-106b-5p contributes to the lung metastasis of breast cancer via targeting CNN1 and regulating Rho/ROCK1 pathway.

OBJECTIVES: Breast cancer has been the second most prevalent and fatal malignancy due to its frequent metastasis to other organs. We aim to study the effects of a key miRNA-mRNA signaling in breast cancer. RESULTS: CNN1 was identified as the key gene in breast cancer by the bioinformatics analysis, and the downregulation of CNN1 in breast cancer tissues and cell lines was observed. Upregulating CNN1 inhibited cell survival, migration, invasion, and adhesion, but enhanced cell apoptosis. miR-106b-5p not only bound to CNN1 mRNA 3'UTR, but also promoted lung metastasis in vivo. Besides, the miR-106b-5p mimic enhanced breast cancer canceration by targeting CNN1 and activating Rho/ROCK1 signaling pathway. CONCLUSION: Overall, our results proved that miR-106b-5p promoted the metastasis of breast cancer by suppressing CNN1 and activating Rho/ROCK1 pathway. METHODS: Bioinformatics analysis was performed to select the key gene in breast cancer. The overexpression and knockdown of Calponin 1 (CNN1) in breast cancer cell lines were performed to conduct cell viability, migrating, invasion, proliferation, adhesion, and apoptosis experiments. To identify the role of miR-106b-5p and Rho/ROCK1 in CNN1-induced breast cancer, a dual-luciferase assay, tumor lung metastasis assay, transcript half-life assay, and Rho/ROCK1 inhibition assay were performed.

MFN1-dependent alteration of mitochondrial dynamics drives hepatocellular carcinoma metastasis by glucose metabolic reprogramming.

BACKGROUND: Mitochondrial dynamics plays an important role in tumour progression. However, how these dynamics integrate tumour metabolism in hepatocellular carcinoma (HCC) metastasis is still unclear. METHODS: The mitochondrial fusion protein mitofusin-1 (MFN1) expression and its prognostic value are detected in HCC. The effects and underlying mechanisms of MFN1 on HCC metastasis and metabolic reprogramming are analysed both in vitro and in vivo. RESULTS: Mitochondrial dynamics, represented by constant fission and fusion, are found to be associated with HCC metastasis. High metastatic HCC displays excessive mitochondrial fission. Among genes involved in mitochondrial dynamics, MFN1 is identified as a leading downregulated candidate that is closely associated with HCC metastasis and poor prognosis. While promoting mitochondrial fusion, MFN1 inhibits cell proliferation, invasion and migration capacity both in vitro and in vivo. Mechanistically, disruption of mitochondrial dynamics by depletion of MFN1 triggers the epithelial-to-mesenchymal transition (EMT) of HCC. Moreover, MFN1 modulates HCC metastasis by metabolic shift from aerobic glycolysis to oxidative phosphorylation. Treatment with glycolytic inhibitor 2-Deoxy-D-glucose (2-DG) significantly suppresses the effects induced by depletion of MFN1. CONCLUSIONS: Our results reveal a critical involvement of mitochondrial dynamics in HCC metastasis via modulating glucose metabolic reprogramming. MFN1 may serve as a novel potential therapeutic target for HCC.

Recombinant TFPI-2 enhances macrophage apoptosis through upregulation of Fas/FasL.

Tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine proteinase inhibitor with inhibitory activity toward activated factor XI, plasma kallikrein, plasmin, certain matrix metalloproteinases, and the tissue factor-activated factor VII complex. In addition, TFPI-2 has other functions such as promoting cell migration and inducing apoptosis. In the present study, we investigated if TFPI-2 induced apoptosis in cultured U937-derived macrophages and the possible signal pathways that involved in the apoptotic process. Apoptotic DNA fragment detection and caspase-3,9 activity measurements indicated that rTFPI-2 promoted U937-derived macrophage apoptosis. Hoechst 33342 assay and flow cytometry further showed that rTFPI-2 induced apoptosis in cultured macrophages in a dose-dependent manner. Because death receptors of the TNF family such as Fas are the best-understood death pathways that recruit Fas-associated death domain (FADD) and procaspase-8 to the receptor in macrophages, we investigated the expression of Fas and its ligand (FasL) and downstream signal caspase-8 by Western blot analysis. The results indicated that the process of apoptosis triggered by rTFPI-2 was, at least in part, actively conducted by U937-derived macrophages possibly through Fas/FasL signal pathway. In brief, rTFPI-2 may have the potential usefulness in inducing macrophages apoptosis, which suggest TFPI-2 might have antiatherogenic effects.