0000000000055043
AUTHOR
Alice Rigoni
Infiltrating mast cell-mediated stimulation of estrogen receptor activity in breast cancer cells promotes the luminal phenotype
Abstract Tumor growth and development is determined by both cancer cell–autonomous and microenvironmental mechanisms, including the contribution of infiltrating immune cells. Because the role of mast cells (MC) in this process is poorly characterized and even controversial, we investigated their part in breast cancer. Crossing C57BL/6 MMTV-PyMT mice, which spontaneously develop mammary carcinomas, with MC-deficient C57BL/6-KitW-sh/W-sh (Wsh) mice, showed that MCs promote tumor growth and prevent the development of basal CK5-positive areas in favor of a luminal gene program. When cocultured with breast cancer cells in vitro, MCs hindered activation of cMET, a master regulator of the basal pr…
Abstract 4054: Mast cells contribute to T cell tolerance against prostate cancer- associated antigens favoring tumor growth
Abstract Treatments for hormone refractory and metastatic prostate cancer (PC) still remain palliative. Also tumor specific vaccinations when tested in the clinical setting showed results lower than expected. A major limitation to active immunotherapy relies on mechanisms of tolerance adopted by the tumor. Indeed, an immunosuppressive environment is established in PC patients, as well as in the TRAMP mouse model of PC, in which peripheral T cell tolerance to the tumor-associated antigen Tag is acquired early during neoplastic transformation, with mechanisms that still need to be fully clarified. Mast cells (MCs) have been described to mediate immunological tolerance in transplantation and i…
Mast cells control the expansion and differentiation of IL-10-competent B cells
Abstract The discovery of B cell subsets with regulatory properties, dependent on IL-10 production, has expanded our view on the mechanisms that control inflammation. Regulatory B cells acquire the ability to produce IL-10 in a stepwise process: first, they become IL-10 competent, a poised state in which B cells are sensitive to trigger signals but do not actually express the Il-10 gene; then, when exposed to appropriate stimuli, they start producing IL-10. Even if the existence of IL-10–competent B cells is now well established, it is not yet known how different immune cell types cross talk with B cells and affect IL-10–competent B cell differentiation and expansion. Mast cells (MCs) contr…
Mast cell targeting hampers prostate adenocarcinoma development but promotes the occurrence of highly malignant neuroendocrine cancers
Abstract Mast cells (MC) are c-Kit–expressing cells, best known for their primary involvement in allergic reactions, but recently reappraised as important players in either cancer promotion or inhibition. Here, we assessed the role of MCs in prostate tumor development. In prostate tumors from both tumor-prone transgenic adenocarcinoma of the mouse prostate (TRAMP) mice and human patients, MCs are specifically enriched and degranulated in areas of well-differentiated (WD) adenocarcinoma but not around poorly differentiated (PD) foci that coexist in the same tumors. We derived novel TRAMP tumor cell lines, representative of WD and PD variants, and through pharmacologic stabilization or geneti…
Imatinib spares cKit-expressing prostate neuroendocrine tumors, whereas kills seminal vesicle epithelial-stromal tumors by targeting PDGFR-β
Abstract Prostate cancer is a leading cause of cancer-related death in males worldwide. Indeed, advanced and metastatic disease characterized by androgen resistance and often associated with neuroendocrine (NE) differentiation remains incurable. Using the spontaneous prostate cancer TRAMP model, we have shown that mast cells (MCs) support in vivo the growth of prostate adenocarcinoma, whereas their genetic or pharmacologic targeting favors prostate NE cancer arousal. Aiming at simultaneously targeting prostate NE tumor cells and MCs, both expressing the cKit tyrosine kinase receptor, we have tested the therapeutic effect of imatinib in TRAMP mice. Imatinib-treated TRAMP mice experience a pa…
Mast cells boost myeloid-derived suppressor cell activity and contribute to the development of tumor-favoring microenvironment
Abstract Inflammation plays crucial roles at different stages of tumor development and may lead to the failure of immune surveillance and immunotherapy. Myeloid-derived suppressor cells (MDSC) are one of the major components of the immune-suppressive network that favors tumor growth, and their interaction with mast cells is emerging as critical for the outcome of the tumor-associated immune response. Herein, we showed the occurrence of cell-to-cell interactions between MDSCs and mast cells in the mucosa of patients with colon carcinoma and in the colon and spleen of tumor-bearing mice. Furthermore, we demonstrated that the CT-26 colon cancer cells induced the accumulation of CD11b+Gr1+ imma…
Mast Cells Infiltrating Inflamed or Transformed Gut Alternatively Sustain Mucosal Healing or Tumor Growth.
Abstract Mast cells (MC) are immune cells located next to the intestinal epithelium with regulatory function in maintaining the homeostasis of the mucosal barrier. We have investigated MC activities in colon inflammation and cancer in mice either wild-type (WT) or MC-deficient (KitW-sh) reconstituted or not with bone marrow-derived MCs. Colitis was chemically induced with dextran sodium sulfate (DSS). Tumors were induced by administering azoxymethane (AOM) intraperitoneally before DSS. Following DSS withdrawal, KitW-sh mice showed reduced weight gain and impaired tissue repair compared with their WT littermates or KitW-sh mice reconstituted with bone marrow-derived MCs. MCs were localized i…
Cross-Talk between Myeloid-Derived Suppressor Cells and Mast Cells Mediates Tumor-Specific Immunosuppression in Prostate Cancer.
Abstract Immunotherapy, including the use of checkpoint inhibitors, is a potent therapeutic approach for some cancers, but has limited success with prostate tumors, in which immune suppression is instigated by the tumor. The immunosuppressive capacity of mast cells, which promote adenocarcinoma development in the prostate, prompted our investigation on whether mast cells promote tolerance to SV40 Large-T antigen, the transforming oncogene in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice. The incidence of adenocarcinoma was reduced in the offspring of a cross between TRAMP mice and mast cell–deficient KitWsh mice. TRAMP mice are tolerant to the SV40 Large T antigen, which is o…