ObjectiveA novel approach to regulate obesity-associated adipose inflammation may be through metabolic reprogramming of macrophages (MΦs). Broadly speaking, MΦs dependent on glucose are pro-inflammatory, classically activated MΦs (CAM), which contribute to adipose inflammation and insulin resistance. In contrast, MΦs that primarily metabolize fatty acids are alternatively activated MΦs (AAM) and maintain tissue insulin sensitivity. In actuality, there is much flexibility and overlap in the CAM-AAM spectrum in vivo dependent upon various stimuli in the microenvironment. We hypothesized that specific lipid trafficking proteins, e.g. fatty acid transport protein 1 (FATP1), would direct MΦ fatty acid transport and metabolism to limit inflammation and contribute to the maintenance of adipose tissue homeostasis.MethodsBone marrow derived MΦs (BMDMs) from Fatp1−/− and Fatp1+/+ mice were used to investigate FATP1-dependent substrate metabolism, bioenergetics, metabolomics, and inflammatory responses. We also generated C57BL/6J chimeric mice by bone marrow transplant specifically lacking hematopoetic FATP1 (Fatp1B−/−) and controls Fatp1B+/+. Mice were challenged by high fat diet (HFD) or low fat diet (LFD) and analyses including MRI, glucose and insulin tolerance tests, flow cytometric, histologic, and protein quantification assays were conducted. Finally, an FATP1-overexpressing RAW 264.7 MΦ cell line (FATP1-OE) and empty vector control (FATP1-EV) were developed as a gain of function model to test effects on substrate metabolism, bioenergetics, metabolomics, and inflammatory responses.ResultsFatp1 is downregulated with pro-inflammatory stimulation of MΦs. Fatp1−/− BMDMs and FATP1-OE RAW 264.7 MΦs demonstrated that FATP1 reciprocally controled metabolic flexibility, i.e. lipid and glucose metabolism, which was associated with inflammatory response. Supporting our previous work demonstrating the positive relationship between glucose metabolism and inflammation, loss of FATP1 enhanced glucose metabolism and exaggerated the pro-inflammatory CAM phenotype. Fatp1B−/− chimeras fed a HFD gained more epididymal white adipose mass, which was inflamed and oxidatively stressed, compared to HFD-fed Fatp1B+/+ controls. Adipose tissue macrophages displayed a CAM-like phenotype in the absence of Fatp1. Conversely, functional overexpression of FATP1 decreased many aspects of glucose metabolism and diminished CAM-stimulated inflammation in vitro. FATP1 displayed acyl-CoA synthetase activity for long chain fatty acids in MΦs and modulated lipid mediator metabolism in MΦs.ConclusionOur findings provide evidence that FATP1 is a novel regulator of MΦ activation through control of substrate metabolism. Absence of FATP1 exacerbated pro-inflammatory activation in vitro and increased local and systemic components of the metabolic syndrome in HFD-fed Fatp1B−/− mice. In contrast, gain of FATP1 activity in MΦs suggested that Fatp1-mediated activation of fatty acids, substrate switch to glucose, oxidative stress, and lipid mediator synthesis are pote...
Background Mean platelet volume (MPV) is a marker of platelet activation. MPV and platelet count (PC) are negatively correlated, and their ratio (MPV/PC) is informative for the diagnosis of malignant tumors. However, the relationship between MPV/PC and colorectal cancer is unclear. This retrospective clinical study aimed to evaluate the diagnostic value of MPV/PC in colorectal cancer. Methods Hematological examinations were performed at initial diagnosis in patients with colorectal cancer ( n = 186) or adenomatous polyp ( n = 132) and healthy controls ( n = 108). Hematological parameters evaluated included white blood cells, red blood cells, hemoglobin, neutrophils, lymphocytes, monocytes, PC, and MPV. Statistical analyses included Student’s t-test, one-way ANOVA or Kruskal-Wallis H test, chi-square tests, Spearman’s correlation test and receiver operating characteristic (ROC). ROC curve was used to evaluate the diagnostic values of MPV and MPV/PC in colorectal cancer. Results Among these groups, MPV was significantly lower in colorectal cancer than in adenomatous polyp ( p = 0.002) and healthy controls ( p < 0.001) but did not significantly differ between adenomatous polyp and healthy controls ( p = 0.210). MPV/PC was lower in colorectal cancer compared with adenomatous polyp and healthy controls ( p < 0.001) and in adenomatous polyp compared with healthy controls ( p = 0.010). MPV did not significantly differ among colorectal cancer subgroups, while MPV/PC significantly differed between TNM stages and the presence/absence of lymph node metastasis. MPV/PC was negatively correlated with the neutrophil to lymphocyte ratio(NLR) ( p = 0.002) and platelet to lymphocyte ratio(PLR) concentration ( p < 0.001). In the differential diagnosis between colorectal cancer and adenomatous polyp, MPV/PC produced a larger ROC curve than MPV, NLR or PLR alone. Using MPV/PC to distinguish between colorectal cancer and controls produced a larger AUC than using MPV or NLR alone. Conclusions MPV/PC may be useful for the diagnosis of colorectal cancer. However, further studies are warranted to include additional regions and more data, to assess the utility of MPV/PC as a novel diagnostic screening tool for colorectal cancer.
Chemotherapeutic resistance in triple-negative breast cancer (TNBC) has brought great challenges to the improvement of patient survival. The mechanisms of taxane chemoresistance in TNBC have not been well investigated. Our results illustrated C-C motif chemokine ligand 20 (CCL20) was significantly elevated during taxane-containing chemotherapy in breast cancer patients with nonpathologic complete response. Furthermore, CCL20 promoted the self-renewal and maintenance of breast cancer stem cells (BCSCs) or breast cancer stem-like cells through protein kinase Cζ (PKCζ) or p38 mitogen-activated protein kinase (MAPK)-mediated activation of p65 nuclear factor kappa B (NF-κB) pathway, significantly increasing the frequency and taxane resistance of BCSCs. Moreover, CCL20-promoted NF-κB activation increased ATP-binding cassette subfamily B member 1 (ABCB1)/multidrug resistance 1 (MDR1) expression, leading to the extracellular efflux of taxane. These results suggested that chemotherapy-induced CCL20 mediated chemoresistance via up-regulating ABCB1. In addition, NF-κB activation increased CCL20 expression, forming a positive feedback loop between NF-κB and CCL20 pathways, which provides sustained impetus for chemoresistance in breast cancer cells. Our results suggest that CCL20 can be a novel predictive marker for taxane response, and the blockade of CCL20 or its downstream pathway might reverse the taxane resistance in breast cancer patients.
Chemotherapy resistance of breast cancer poses a great challenge to the survival of patients. During breast cancer treatment, the development of intrinsic and acquired drug resistance tends to further induce adverse prognosis, such as metastasis. In recent years, the progress of research on cytokine‐modulated tumor microenvironment and breast cancer stem cells (BCSCs) has shed light on defining the mechanisms of drug resistance gradually. In this review, we have discussed cytokine regulation on breast cancer chemoresistance. Cytokines can affect tumor cell behavior or reprogram tumor niche through specific signaling pathways, thereby regulating the progress of drug resistance. In addition, we summarized the mutually regulatory networks between cytokines and BCSCs in mediating chemoresistance. Cytokines in the tumor microenvironment can regulate the self‐renewal and survival of BCSCs in a variety of ways, sequentially promoting chemotherapeutic resistance. Therefore, the combinational treatment of BCSC targeting and cytokine blockade may have a positive effect on the clinical treatment of breast cancer.
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