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Tumor-associated macrophages promote neuroblastoma via STAT3 phosphorylation and up-regulation of c-MYC.

ABSTRACT: Tumor-associated macrophages (TAMs) are strongly associated with poor survival in neuroblastomas that lack MYCN amplification. To study TAM action in neuroblastomas, we used a novel murine model of spontaneous neuroblastoma lacking MYCN amplification, and observed recruitment and polarization of TAMs, which in turn enhanced neuroblastoma proliferation and growth. In both murine and human neuroblastoma cells, we found that TAMs increased STAT3 activation in neuroblastoma cells and transcriptionally up-regulated the MYC oncogene. Analysis of human neuroblastoma tumor specimens revealed that MYC up-regulation correlates with markers of TAM infiltration. In an IL6ko neuroblastoma model, the absence of IL-6 protein had no effect on tumor development and prevented neither STAT3 activation nor MYC up-regulation. In contrast, inhibition of JAK-STAT activation using AZD1480 or the clinically admissible inhibitor ruxolitinib significantly reduced TAM-mediated growth of neuroblastomas implanted subcutaneously in NOD scid gamma mice. Our results point to a unique mechanism in which TAMs promote tumor cells that lack amplification of an oncogene common to the malignancy by up-regulating transcriptional expression of a distinct oncogene from the same gene family, and underscore the role of IL-6-independent activation of STAT3 in this mechanism. Amplification of MYCN or constitutive up-regulation of MYC protein is observed in approximately half of high-risk tumors; our findings indicate a novel role of TAMs as inducers of MYC expression in neuroblastomas lacking independent oncogene activation.

SUBMITTER: Hadjidaniel MD

PROVIDER: S-EPMC5710942 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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Tumor-associated macrophages promote neuroblastoma via STAT3 phosphorylation and up-regulation of c-MYC.

Hadjidaniel Michael D MD Muthugounder Sakunthala S Hung Long T LT Sheard Michael A MA Shirinbak Soheila S Chan Randall Y RY Nakata Rie R Borriello Lucia L Malvar Jemily J Kennedy Rebekah J RJ Iwakura Hiroshi H Akamizu Takashi T Sposto Richard R Shimada Hiroyuki H DeClerck Yves A YA Asgharzadeh Shahab S

Oncotarget 20170916 53

Tumor-associated macrophages (TAMs) are strongly associated with poor survival in neuroblastomas that lack <i>MYCN</i> amplification. To study TAM action in neuroblastomas, we used a novel murine model of spontaneous neuroblastoma lacking <i>MYCN</i> amplification, and observed recruitment and polarization of TAMs, which in turn enhanced neuroblastoma proliferation and growth. In both murine and human neuroblastoma cells, we found that TAMs increased STAT3 activation in neuroblastoma cells and t ...[more]

PMID: 29207662

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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.

Dataset Information

Tumor-associated macrophages promote neuroblastoma via STAT3 phosphorylation and up-regulation of c-MYC.

Publications

Tumor-associated macrophages promote neuroblastoma via STAT3 phosphorylation and up-regulation of c-MYC.

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