High-salt diets are associated with an elevated risk of autoimmune diseases, and immune dysregulation plays a key role in cancer development. However, the correlation between highsalt diets (HSD) and cancer development remains unclear. Here, we report that HSD increases the local concentration of sodium chloride in tumour tissue, inducing high osmotic stress that decreases both the production of cytokines required for myeloid-derived suppressor cells (MDSCs) expansion and MDSCs accumulation in the blood, spleen, and tumour. Consequently, the two major types of MDSCs change their phenotypes: monocytic-MDSCs differentiate into antitumour macrophages, and granulocytic-MDSCs adopt pro-inflammatory functions, thereby reactivating the antitumour actions of T cells. In addition, the expression of p38 mitogen-activated protein kinase-dependent nuclear factor of activated T cells 5 is enhanced in HSD-induced M-MDSC differentiation. Collectively, our study indicates that high-salt intake inhibits tumour growth in mice by activating antitumour immune surveillance through modulating the activities of MDSCs.
BackgroundMelanoma is a leading cause of cancer death worldwide, and SMI-4a and G-Rh2 exert anti-tumor activity in multiple cancer. However, SMI-4a as well as a synergistic relationship between SMI-4a and G-Rh2 in anti-melanoma capacity are still unknown. Therefore, we investigated the effects of SMI-4a and combined SMI-4a with G-Rh2 on the viability, apoptosis and autophagy of melanoma, and to preliminarily explore the underlying mechanism of SMI-4a and combined SMI-4a with G-Rh2 in inhibiting tumor growth.MethodsCell viability was examined with cell counting Kit 8 assay and colony formation assay; Apoptosis was evaluated by flow cytometry and Caspase 3/7 activity assay; Western blotting was used to test proteins related to autophagy and the AKT/mammalian target of rapamycin (mTOR) signaling pathway; Tumor xenograft model in BALB/c nude mice was performed to evaluate the effects of SMI-4a and combined SMI-4a with G-Rh2 in anti-melanoma in vivo.ResultsSMI-4a, a pharmacological inhibitor of PIM-1, could decrease cell viability, induce apoptosis, and promote Caspase 3/7 activity in both A375 and G361 melanoma cells, and SMI-4a inhibited tumor growth by inducing autophagy via down-regulating AKT/mTOR axis in melanoma cells. Furthermore, G-Rh2 amplified the anti-tumor activity of SMI-4a in melanoma cells via strengthening autophagy.ConclusionsOur results suggested that SMI-4a could enhance autophagy-inducing apoptosis by inhibiting AKT/mTOR signaling pathway in melanoma cells, and G-Rh2 could enhance the effects of SMI-4a against melanoma cancer via amplifying autophagy induction. This study demonstrates that combined SMI-4a and G-Rh2 might be a novel alternative strategy for melanoma treatment.Electronic supplementary materialThe online version of this article (10.1186/s13020-018-0168-y) contains supplementary material, which is available to authorized users.
The present study aimed to investigate the existence of immunoregulation-associated long non-coding (lnc)RNAs mediated by T lymphocytes in the wound surfaces of diabetic foot ulcers (DFUs). The wound skin tissues of patients receiving debridement for trauma or DFUs associated with infection were obtained. Dermatological histological changes were observed by pathological staining, and T lymphocyte subsets and inflammation-associated cytokines were identified. Gene chip technology was used to screen for lncRNAs regulated by immune cells. The wound skin structure in the control group was revealed to be complete, and the inflammatory response was not marked. However, the wound skin structure in the ulcer group was disordered and exhibited a notable inflammatory response. Compared with the control group, expression levels of cluster of differentiation (CD)3 and CD8 in the wound surface tissues of the ulcer group were significantly increased, while the expression levels of interleukin (IL)-1β, IL-2, IL-10, interferon-γ and tumor necrosis factor-α were significantly upregulated. A target regulatory association was identified between downregulated lncRNA-ENST00000411554 and upregulated mitogen-activated protein kinase (MAPK)1 in DFU tissues, and a negative correlation was detected between this RNA and protein. The present results suggested that an immune functional disorder of T lymphocytes may be closely associated with the development of DFUs. Furthermore, activation of the MAPK signal transduction pathway mediated by the lncRNA-ENST00000411554/MAPK1 axis may affect the DFU immune regulatory imbalance.
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