Abstract
We tested microencapsulated rapamycin (eRapa, ~2.2 mg/kg rapamycin/mouse/day) in carcinogen (azoxymethane, AOM) + inflammatory agent (dextran sodium sulfate, DSS) colon cancer. WT BL6 mice ...fed eRapa before, and during AOM/DSS had significantly fewer colon tumors and tumor burden than control fed mice (empty microcapsules). eRapa prevented colon cancer in δ TCR KO mice lacking γδ T cells but not in IFN-γ KO mice. In carcinogen (DMBA) + inflammatory agent (TPA) skin cancer, IFN-γ and γδ T cells were both needed for eRapa cancer prevention, showing tumor-specific and common immune requirements for eRapa-mediated cancer prevention. In βδ TCR KO mice lacking all T cells, AOM/DSS induced no cancer or only few tumors, suggesting αβ T cells are required for colon neoplasia and cancer in the AOM/DSS model. Protection from acute colitis in this model usually predicts colon cancer protection. Strikingly, however, eRapa did not prevent acute clinical or histologic colitis induced by DSS, despite cancer protection, suggesting effects on chronic colitis, or induction of cancer-protective but not acute colitis-protective mechanisms. In acute colitis, eRapa significantly decreased spleen and colon weights and CD3+CD4+ T cells, and increased mesenteric lymph node γδ T cells (with decreased Vγ1.1+ and increased Vγ2+ subsets) consistent with altered inflammation and reduced CD4-CXCR3+ and CD4-α4β7 T cells (likely γδ T cells) consistent with altered trafficking but did not affect CCR9+ T cells. In chronic colitis, eRapa significantly increased γδ T cells (with no changes in Vγ1.1+ or Vγ2+ subsets) that could mediate cancer protection. These novel immune effects of rapamycin help define its cancer prevention mechanisms and define novel clinical uses.
In epigenetic signaling pathways, histone tails are heavily modified, resulting in the recruitment of effector molecules that can influence transcription. One such molecule, plant homeodomain finger ...protein 20 (PHF20), uses a Tudor domain to read dimethyl lysine residues and is a known component of the MOF (male absent on the first) histone acetyltransferase protein complex, suggesting it plays a role in the cross-talk between lysine methylation and histone acetylation. We sought to investigate the biological role of PHF20 by generating a knockout mouse. Without PHF20, mice die shortly after birth and display a wide variety of phenotypes within the skeletal and hematopoietic systems. Mechanistically, PHF20 is not required for maintaining the global H4K16 acetylation levels or locus specific histone acetylation but instead works downstream in transcriptional regulation of MOF target genes.
Background: PHF20 is a methyl lysine binding protein that is a component of the MOF histone acetyltransferase protein complex.
Results: PHF20 knockout mouse die just after birth but display normal H4K16Ac levels.
Conclusion: Promoters that are marked with high H4K16Ac levels display reduced gene expression when PHF20 is lost.
Significance: PHF20 works downstream of the H4K16Ac mark to regulate transcription.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
eRapa extends life in mice and cancer prevention could be a mechanism. Rapamycin inhibits mTOR, which has significant immune effects that are surprisingly unstudied in cancer therapy or ...prevention. We hypothesize that cancer prevention by eRapa is mediated by improved cancer immune surveillance, which we tested in the well-established DMBA/TPA carcinogen-induced skin cancer model. Mice got eRapa or control chow, and skin tumors were induced with DMBA/TPA over 24 weeks. eRapa reduced benign (p=.001) and malignant (p=.05) tumors in WT mice. T cells and IFN-γ mediate cancer immune surveillance. eRapa reduced skin tumors in βδ KO mice lacking all T cells (p=.04), but not in IFN-γ KO mice (p=.13), consistent with loss of beneficial eRapa-induced, non-T cell IFN-γ. In support, WT or IFN-γ KO T cell transfer into IFN-γ KO mice did not alter eRapa cancer prevention in DMBA/TPA. In WT mice on DMBA/TPA, eRapa increased IFN-γ-producing natural killer cells (p=.01) that could mediate skin cancer immune surveillance, and decreased CD34+CD49fint skin cancer stem cells (p=.01) and CXCR3+ T cells (p<.001) that contribute to cancer in this model. eRapa reduced skin pAKT with divergent mTORC1/2 effects needing more study. eRapa appeared safe (no increased Tregs or reduced protection in infection and autoimmunity models). A widely applicable, safe and tolerable cancer prevention agent would be highly useful. Understanding its immune mechanisms could improve efficacy and widen applications.
A comprehensive breast cancer screening program needs to include risk assessment in addition to clinical breast examination and mammography. Women identified as being at increased risk should have an ...individualized schedule of screening mammography and a proven prevention program tailored to their level of risk. In this article, Drs Cardenas and Frisch review risk factors, screening methods, and individual risk assessment, then explain how to use them in conjunction to identify tumors at an earlier, more curable stage.
Abstract
Though many cell-intrinsic genetic and genomic alterations contributing to tumorigenesis of T cell acute lymphoblastic leukemia/lymphoma (T-ALL) have been uncovered, the contributions of ...non-tumor cells and their associated signals in the tumor microenvironment have remained obscure. To address whether the tumor microenvironment contributes to T-ALL tumor growth, we first analyzed the thymic microenvironment during T-ALL progression in murine models of T-ALL. The cellularity and architecture of the thymic stroma becomes increasingly aberrant during initiation and progression of disease, such that tumor cells accumulate and proliferate in epithelial-free regions at the periphery of the thymus. In addition to proliferating tumor cells, these thymic epithelial free regions contain vasculature, fibroblast networks, and an accumulation of dendritic cells. Interestingly, a subset of conventional thymic dendritic cells is greatly expanded in tumor-bearing thymi. To determine if cellular subsets in the tumor microenvironment contribute to T-ALL growth, we established a co-culture system containing primary T-ALL cells and purified stromal subsets taken directly from the tumor microenvironment. We found that ex vivo lymphoma cells require the presence of tumor-associated stroma for survival and proliferation. Strikingly, tumor-associated myeloid cells are necessary and sufficient to support ex vivo lymphoma survival, with tumor-associated dendritic cells most potently promoting T-ALL growth. Tumor-associated dendritic cells, but not wild-type thymic dendritic cells, are uniquely capable of supporting T-ALL survival. Global gene expression profiling reveals that tumor-associated dendritic cells exhibit limited altered gene-expression profiles, such that they upregulate transcripts associated with tumor-associated macrophages. Importantly, we find that T-ALL cells from metastatic tumor sites retain their dependence on stromal cells from the tumor microenvironment, and dendritic cells from metastatic tumors are sufficient to promote T-ALL survival. Thus, dendritic cells both at the primary tumor site and at sites of disseminated disease are sufficient to support growth of T-ALL cells. To determine if T-ALL cells preferentially contact dendritic cells in an intact thymic microenvironment, we used 2-photon microscopy to visualize interactions of thymic dendritic cells with T-ALL cells versus wild-type thymocytes. T-ALL cells interact with thymic dendritic cells with increased frequency and duration relative to wild-type thymocytes. Taken together, these studies strongly implicate endogenous myeloid cells, and particularly dendritic cells in the tumor microenvironment as potent stimulators of T-ALL growth, and suggest tumor-associated dendritic cells or their associated mitogenic signals could serve as novel therapeutic targets.
Citation Format: Todd A. Triplett, Kim T. Cardenas, Jessica N. Jones, Hilary J. Selden, Guadalupe J. Jasso, Sadhana Balasubramanyam, Zicheng Hu, Li LiQi, Paul E. Love, Lauren IR Ehrlich. Altered myeloid cells in the tumor microenvironment promote growth of T cell acute lymphoblastic leukemia. abstract. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr A02.
Cancer prevention is a cost-effective alternative to treatment. Oral rapamycin (eRapa) prevents distinct cancers and extends life in mice1, making it a candidate broad-spectrum cancer prevention ...agent. Rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), has significant immune effects that are unstudied in cancer. We hypothesize that eRapa prevents cancer through improved cancer immune surveillance, which we tested in a carcinogen-induced, inflammation-driven skin cancer model.
eRapa was used at 14ppm microencapsulated rapamycin. Skin cancer. Wild-type C57BL/6 (WT) or syngeneic βδ knockout (KO) and interferon (IFN)-γ KO mice (lacking all T cells or IFN-γ, respectively) got eRapa or control for 1month, followed once with the carcinogen 7,12-dimethylbenzaanthracene (DMBA), then twice weekly applications with the inflammatory agent 12-O-tetradecanoylphorbol (TPA) for 24weeks. Flow cytometry assessed cells and IFN-γ. Statistics. Tumors (unpaired t test and 2-way ANOVA) and malignant degeneration (Fischer exact test).
eRapa reduced benign (p=.004) and malignant (p=.03) tumors in WT mice. T cells and IFN-γ mediate cancer immune surveillance so their effects on eRapa cancer prevention were studied. eRapa reduced skin tumors in βδ KO mice lacking all T cells (p=.04), but not in IFN-γ KO mice (p=.13), consistent with loss of beneficial eRapa-induced, non-T cell IFN-γ. In support, WT or IFN-γ KO T cell transfer into IFN-γ KO mice did not alter eRapa cancer prevention in this model. In WT mice on DMBA/TPA, eRapa increased IFN-γ producing dermal natural killer (NK) cells (p<.0001) that can mediate skin cancer immune surveillance. There was a loss of this eRapa-mediated dermal NK cell increase in IFN-γ KO mice, suggesting that eRapa-mediated IFN-γ facilitated local NK cell accumulation.
eRapa prevents carcinogen and inflammation-induced skin cancer, which involves a non-T cell that could be an NK cell, and is IFN-γ dependent. We also show that eRapa prevents cancer and extends life in distinct mouse cancer models, which paves the way for use of mTOR inhibitors as broad spectrum human cancer prevention agents.
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17.
35 Dao, Vinh; Pandeswara, Sri Lakshmi; Cardenas, Kim ...
Cytokine (Philadelphia, Pa.),
11/2014, Volume:
70, Issue:
1
Journal Article
Peer reviewed
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
18.
Tbx1 antagonizes thymus organogenesis (86.4) Cardenas, Kim T.; Liu, Zhijie; Laurent, Micheline ...
The Journal of immunology (1950),
04/2009, Volume:
182, Issue:
1_Supplement
Journal Article
Peer reviewed
Abstract
The thymus and parathyroids originate from organ-specific domains in endoderm of the 3rd pharyngeal pouch (PP), identified by Foxn1 and Gcm2 expression respectively at embryonic day 11 ...(E11). The molecular mechanisms regulating fate determination in the 3rd PP are not clear. Our studies show that neural crest cells (NCCs) play a role in this process (Griffin et al, in press). We also showed that lack of Sonic hedgehog (Shh) results in absence of the parathyroid domain and expansion of the thymus domain (Moore-Scott et al, 2005). It has been proposed that the Tbx1 transcription factor is also required for thymus development and is regulated by Shh. However, Tbx1 is expressed in the Gcm2, but not the Foxn1 domain of 3rd PP at E10.5.
We propose a model of thymus organogenesis in which 3rd PP endoderm assumes a thymus fate unless Shh plus NCC-derived signals specify a parathyroid fate. We further propose that Tbx1 is required to establish parathyroid fate and is non-permissive for thymus fate. To test the model, we generated knock-in mice containing a Cre-inducible allele that allows temporal and spatial control of Tbx1 expression. Ectopic Tbx1 expression using Foxn1Cre resulted in markedly hypoplastic thymi, supporting the notion that Tbx1 antagonizes thymus differentiation. Current studies focus on determining the molecular basis for this phenotype and testing the effects of activating Tbx1 expression at earlier stages. Supported by NIH HD056315 to ER and HD035920 to NM.
Of 17 genes annotated in the Arabidopsis genome database as cinnamyl alcohol dehydrogenase (CAD) homologues, an in silico analysis revealed that 8 genes were misannotated. Of the remaining nine, six ...were catalytically competent for NADPH-dependent reduction of p-coumaryl, caffeyl, coniferyl, 5-hydroxyconiferyl, and sinapyl aldehydes, whereas three displayed very low activity and only at very high substrate concentrations. Of the nine putative CADs, two (AtCAD5 and AtCAD4) had the highest activity and homology (≈83% similarity) relative to bona fide CADs from other species. AtCAD5 used all five substrates effectively, whereas AtCAD4 (of lower overall catalytic capacity) poorly used sinapyl aldehyde; the corresponding 270-fold decrease in kenzresulted from higher Kmand lower kcatvalues, respectively. No CAD homologue displayed a specific requirement for sinapyl aldehyde, which was in direct contrast with un-founded claims for a so-called sinapyl alcohol dehydrogenase in angiosperms. AtCAD2, 3, as well as AtCAD7 and 8 (highest homology to sinapyl alcohol dehydrogenase) were catalytically less active overall by at least an order of magnitude, due to increased Kmand lower kcatvalues. Accordingly, alternative and/or bifunctional metabolic roles of these proteins in plant defense cannot be ruled out. Comprehensive anylses of lignified tissues of various Arabidopsis knock-out mutants (for AtCAD5, 6, and 9) at different stages of growth/development indicated the presence of functionally redundant CAD metabolic networks. Moreover, disruption of AtCAD5 expression had only a small effect on either overall lignin amounts deposited, or on syringyl-guaiacyl compositions, despite being the most catalytically active form in vitro.
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