25 research outputs found
Oxygen Levels Do Not Determine Radiation Survival of Breast Cancer Stem Cells
For more than a century oxygen has been known to be one of the most powerful radiosensitizers. However, despite decades of preclinical and clinical research aimed at overcoming tumor hypoxia, little clinical progress has been made so far. Ionizing radiation damages DNA through generation of free radicals. In the presence of oxygen these lesions are chemically modified, and thus harder to repair while hypoxia protects cells from radiation (Oxygen enhancement ratio (OER)). Breast cancer stem cells (BSCSs) are protected from radiation by high levels of free radical scavengers even in the presence of oxygen. This led us to hypothesize that BCSCs exhibit an OER of 1. Using four established breast cancer cell lines (MCF-7, T47D, MDA-MB-231, SUM159PT) and primary breast cancer samples, we determined the number of BCSCs using cancer stem cell markers (ALDH1, low proteasome activity), compared radiation clonogenic survival and mammosphere formation under normoxic and hypoxic conditions, and correlated these results to the expression levels of key members of the free radical scavenging systems. The number of BCSCs increased with increased aggressiveness of the cancer. This correlated with increased radioresistance (SF8Gy), and decreasing OERs. When cultured as mammospheres, breast cancer cell lines and primary samples were highly radioresistant and not further protected by hypoxia (OER∼1)
Autocrine Adenosine Regulates Tumor Polyfunctional CD73<sup>+</sup>CD4<sup>+</sup> Effector T Cells Devoid of Immune Checkpoints.
The production of CD73-derived adenosine (Ado) by Tregs has been proposed as a resistance mechanism to anti-PD-1 therapy in murine tumor models. We reported that human Tregs express the ectonucleotidase CD39, which generates AMP from ATP, but do not express the AMPase CD73. In contrast, CD73 defined a subset of effector CD4 <sup>+</sup> T cells (Teffs) enriched in polyfunctional Th1.17 cells characterized by expression of CXCR3, CCR6, and MDR1, and production of IL17A/IFNγ/IL22/GM-CSF. CD39 <sup>+</sup> Tregs selectively targeted CD73 <sup>+</sup> Teffs through cooperative degradation of ATP into Ado inhibiting and restricting the ability of CD73 <sup>+</sup> Teffs to secrete IL17A. CD73 <sup>+</sup> Teffs infiltrating breast and ovarian tumors were functionally blunted by Tregs expressing upregulated levels of CD39 and ATPase activity. Moreover, tumor-infiltrating CD73 <sup>+</sup> Teffs failed to express inhibitory immune checkpoints, suggesting that CD73 might be selected under pressure from immune checkpoint blockade therapy and thus may represent a nonredundant target for restoring antitumor immunity.Significance: Polyfunctional CD73 <sup>+</sup> T-cell effectors lacking other immune checkpoints are selectively targeted by CD39 overexpressing Tregs that dominate the breast tumor environment. Cancer Res; 78(13); 3604-18. ©2018 AACR
RETRACTED ARTICLE: Critical role of CCDC6 in the neoplastic growth of testicular germ cell tumors
Congenital Myasthenic Syndromes or Inherited Disorders of Neuromuscular Transmission: Recent Discoveries and Open Questions
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IL-23 and IL-2 activation of STAT5 is required for optimal IL-22 production in ILC3s during colitis
Signal transducer and activator of transcription (STAT) proteins have critical roles in the development and function of immune cells. STAT signaling is often dysregulated in patients with inflammatory bowel disease (IBD), suggesting the importance of STAT regulation during the disease process. Moreover, genetic alterations in
and
(e.g., deletions, mutations, and single-nucleotide polymorphisms) are associated with an increased risk for IBD. In this study, we elucidated the precise roles of STAT5 signaling in group 3 innate lymphoid cells (ILC3s), a key subset of immune cells involved in the maintenance of gut barrier integrity. We show that mice lacking either STAT5a or STAT5b are more susceptible to
-mediated colitis and that interleukin-2 (IL-2)- and IL-23-induced STAT5 drives IL-22 production in both mouse and human colonic lamina propria ILC3s. Mechanistically, IL-23 induces a STAT3-STAT5 complex that binds IL-22 promoter DNA elements in ILC3s. Our data suggest that STAT5a/b signaling in ILC3s maintains gut epithelial integrity during pathogen-induced intestinal disease
LAG3 Regulatory T Cells Restrain Interleukin-23-Producing CX3CR1 Gut-Resident Macrophages during Group 3 Innate Lymphoid Cell-Driven Colitis.
Interleukin-22 (IL-22)-producing group 3 innate lymphoid cells (ILC3) maintains gut homeostasis but can also promote inflammatory bowel disease (IBD). The regulation of ILC3-dependent colitis remains to be elucidated. Here we show that Foxp3 regulatory T cells (Treg cells) prevented ILC3-mediated colitis in an IL-10-independent manner. Treg cells inhibited IL-23 and IL-1β production from intestinal-resident CX3CR1 macrophages but not CD103 dendritic cells. Moreover, Treg cells restrained ILC3 production of IL-22 through suppression of CX3CR1 macrophage production of IL-23 and IL-1β. This suppression was contact dependent and was mediated by latent activation gene-3 (LAG-3)-an immune checkpoint receptor-expressed on Treg cells. Engagement of LAG-3 on MHC class II drove profound immunosuppression of CX3CR1 tissue-resident macrophages. Our study reveals that the health of the intestinal mucosa is maintained by an axis driven by Treg cells communication with resident macrophages that withhold inflammatory stimuli required for ILC3 function
The CHRNE 1293insG founder mutation is a frequent cause of congenital myasthenia in North Africa
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