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  • 1
    In: Molecular Oncology, Wiley, Vol. 17, No. 8 ( 2023-08), p. 1492-1513
    Abstract: Snail1 is a transcriptional factor required for cancer‐associated fibroblast (CAF) activation, and mainly detected in CAFs in human tumors. In the mouse mammary tumor virus‐polyoma middle tumor‐antigen (MMTV‐PyMT) model of murine mammary gland tumors, Snai1 gene deletion, besides increasing tumor‐free lifespan, altered macrophage differentiation, with fewer expressing low levels of MHC class II. Snail1 was not expressed in macrophages, and in vitro polarization with interleukin‐4 (IL4) or interferon‐γ (IFNγ) was not altered by Snai1 gene depletion. We verified that CAF activation modified polarization of naïve bone‐marrow‐derived macrophages (BMDMΦs). When BMDMΦs were incubated with Snail1‐expressing (active) CAFs or with conditioned medium derived from these cells, they exhibited a lower cytotoxic capability than when incubated with Snail1‐deleted (inactive) CAFs. Gene expression analysis of BMDMΦs polarized by conditioned medium from wild‐type or Snai1‐deleted CAFs revealed that active CAFs differentially stimulated a complex combination of genes comprising genes that are normally induced by IL4, downregulated by IFNγ, or not altered during the two canonical differentiations. Levels of RNAs relating to this CAF‐induced alternative polarization were sensitive to inhibitors of factors specifically released by active CAFs, such as prostaglandin E 2 and TGFβ. Finally, CAF‐polarized macrophages promoted the activation of the immunosuppressive regulatory T cells (T‐regs). Our results imply that an active CAF‐rich tumor microenvironment induces the polarization of macrophages to an immunosuppressive phenotype, preventing the macrophage cytotoxic activity on tumor cells and enhancing the activation of T‐reg cells.
    Type of Medium: Online Resource
    ISSN: 1574-7891 , 1878-0261
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2322586-5
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  • 2
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 81, No. 2 ( 2021-01-15), p. 438-451
    Abstract: Tumors are complex tissues composed of transformed epithelial cells as well as cancer-activated fibroblasts (CAF) that facilitate epithelial tumor cell invasion. We show here that CAFs and other mesenchymal cells rely much more on glutamine than epithelial tumor cells; consequently, they are more sensitive to inhibition of glutaminase. Glutamine dependence drove CAF migration toward this amino acid when cultured in low glutamine conditions. CAFs also invaded a Matrigel matrix following a glutamine concentration gradient and enhanced the invasion of tumor cells when both cells were cocultured. Accordingly, glutamine directed invasion of xenografted tumors in immunocompromised mice. Stimulation of glutamine-driven epithelial tumor invasion by fibroblasts required previous CAF activation, which involved the TGFβ/Snail1 signaling axis. CAFs moving toward Gln presented a polarized Akt2 distribution that was modulated by the Gln-dependent activity of TRAF6 and p62 in the migrating front, and depletion of these proteins prevented Akt2 polarization and Gln-driven CAF invasion. Our results demonstrate that glutamine deprivation promotes CAF migration and invasion, which in turn facilitates the movement of tumor epithelial cells toward nutrient-rich territories. These results provide a novel molecular mechanism for how metabolic stress enhances invasion and metastasis. Significance: Cancer-associated fibroblasts migrate and invade toward free glutamine and facilitate invasion of tumor epithelial cells, accounting for their movement away from the hostile conditions of the tumor towards nutrient-rich adjacent tissues.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2021
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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