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M2 tumor-associated macrophages produce interleukin-17 to suppress oxaliplatin-induced apoptosis in hepatocellular carcinoma.

ABSTRACT: M2 macrophages are a major component of the tumor microenvironment and are important promoters of tumor occurrence and progression. In this study, we detected large numbers of M2 macrophages in hepatocellular carcinoma tissues using immunohistochemistry and immunofluorescence. Moreover, upon oxaliplatin treatment, the M2 macrophages overexpressed interleukin-17, an important inflammatory cytokine, and thus inhibited oxaliplatin-induced apoptosis. By knocking down the interleukin-17 receptor and lysosome-associated membrane protein 2A (a key protein in chaperone-mediated autophagy) in hepatocellular carcinoma cells, we found that interleukin-17 stimulated chaperone-mediated autophagy, which further suppressed apoptosis upon oxaliplatin treatment. Chaperone-mediated autophagy induced tolerance to oxaliplatin treatment by reducing cyclin D1 expression; thus, cyclin D1 overexpression stimulated oxaliplatin-induced apoptosis. In addition, cyclin D1 expression was inhibited by interleukin-17, but increased when the interleukin-17 receptor was knocked down. Thus M2 macrophages in the hepatocellular carcinoma microenvironment generate large amounts of interleukin-17, which suppress oxaliplatin-induced tumor cell apoptosis by activating chaperone-mediated autophagy and in turn reducing cyclin D1 expression. These findings may facilitate the development of novel therapeutic strategies for chemorefractory liver cancer.

SUBMITTER: Guo B

PROVIDER: S-EPMC5546494 | biostudies-other | 2017 Jul

REPOSITORIES: biostudies-other

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Project description:Background & aimsCancer stem cells (CSCs) can contribute to hepatocellular carcinoma (HCC) progression and recurrence after therapy. The presence of tumor-associated macrophages (TAMs) in patients with HCC is associated with poor outcomes. It is not clear whether TAMs interact with CSCs during HCC development. We investigated whether TAMs affect the activities of CSCs in the microenvironment of human HCCs.MethodsHCCs were collected from 17 patients during surgical resection and single-cell suspensions were analyzed by flow cytometry. CD14(+) TAMs were isolated from the HCC cell suspensions and placed into co-culture with HepG2 or Hep3B cells, and CSC functions were measured. The interleukin 6 (IL6) receptor was blocked with a monoclonal antibody (tocilizumab), and signal transducer and activator of transcription 3 was knocked down with small hairpin RNAs in HepG2 cells. Xenograft tumors were grown in NOD-SCID/Il2Rg(null) mice from human primary HCC cells or HepG2 cells.ResultsCD44(+) cells from human HCCs and cell lines formed more spheres in culture and more xenograft tumors in mice than CD44(-) cells, indicating that CD44(+) cells are CSCs. Incubation of the CD44(+) cells with TAMs promoted expansion of CD44(+) cells, and increased their sphere formation in culture and formation of xenograft tumors in mice. In human HCC samples, the numbers of TAMs correlated with the numbers of CD44(+) cells. Of all cytokines expressed by TAMs, IL6 was increased at the highest level in human HCC co-cultures, compared with TAMs not undergoing co-culture. IL6 was detected in the microenvironment of HCC samples and induced expansion of CD44(+) cells in culture. Levels of IL6 correlated with stages of human HCCs and detection of CSC markers. Incubation of HCC cell lines with tocilizumab or knockdown of signal transducer and activator of transcription 3 in HCC cells reduced the ability of TAMs to promote sphere formation by CD44+ cells in culture and growth of xenograft tumors in mice.ConclusionsCD44(+) cells isolated from human HCC tissues and cell lines have CSC activities in vitro and form a larger number of xenograft tumors in mice than CD44(-) cells. TAMs produce IL6, which promotes expansion of these CSCs and tumorigenesis. Levels of IL6 in human HCC samples correlate with tumor stage and markers of CSCs. Blockade of IL6 signaling with tocilizumab, a drug approved by the Food and Drug Administration for treatment of rheumatoid arthritis, inhibits TAM-stimulated activity of CD44(+) cells. This drug might be used to treat patients with HCC.

Project description:Background:Tumor-associated macrophage (TAM) is emerging as one of the important complications in cancer promotion. Interleukin-17 (IL-17), a potent pro-inflammatory cytokine, plays an active role in promoting M2 macrophage differentiation (TAMs are M2-like phenotypes). In this study, we aimed to evaluate that IL-17 stimulates key phenotypic and functional signatures of M2 macrophages associated with cancer progression in non-small-cell lung cancer (NSCLC) patients. Patients and methods:The markers and cytokines of M2 macrophages were detected in THP-1-derived macrophages and mouse peritoneal macrophages treated with IL-17. The activation of nuclear factor kappa B (NF-?B) and nuclear localization of p65 in IL-17-treated cells were investigated. The BAY11-7082 inhibitor and the siRNA of p65 were used to block the NF-?B activation. A total of 85 patients who underwent surgery for histologically verified NSCLC were enrolled in this study. The expression of IL-17 and M2 macrophage markers were assessed by immunostaining. Survivals were estimated using the Kaplan-Meier method. Results:The CD163 and CD206 cell surface markers and transforming growth factor beta (TGF-?), vascular endothelial growth factor (VEGF) and IL-10 of M2 macrophages were significantly increased in IL-17-treated THP-1-derived macrophages in a dose-dependent manner. IL-17 increased the mRNA levels of Arginase I and Fizz1, the phosphorylation of IkB? and nuclear localization of p65 (a subunit of NF-?B). The BAY11-7082 abrogated IL-17-induced CD206 and CD163 expression, TGF-?, VEGF, IL-10, Arginase I and Fizz1 expression and p65 nuclear translocation. Further experiments showed that IL-17 induced the expression of CD206, CD163, Arginase I, Fizz1 and Ym1 in mouse peritoneal macrophages that were inhibited by siRNA of p65. The immunostaining experiments on human NSCLC tissues indicated that high IL-17 expression was significantly correlated with CD163 and c-Maf. The intratumoral IL-17+ CD163+ c-Maf+ cells were associated with NSCLC progression. Conclusion:IL-17 stimulated macrophages to M2-like phenotypes via NF-?B activation. IL-17 may be a potential therapeutic target for NSCLC.

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M2 tumor-associated macrophages produce interleukin-17 to suppress oxaliplatin-induced apoptosis in hepatocellular carcinoma.

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