Project description:Cancer stem-like cells are hypothesized to be the major tumor initiating cell (TIC) population of human cutaneous squamous cell carcinoma (hcSCC), but the molecular alterations underpinning their cellular phenotype remain undefined. Here, a small CD133+CD31-CD45-CD61-CD24- (CD133+) cell population enriched for self-renewing and TIC features was isolated by sorting from primary hcSCC tumors. CD133+ cells show enhanced spheroid formation in vitro and tumor generation in vivo. Gene expression profiling comparing CD133+ with CD133- cells revealed that CD133+ cells expressed enriched stem cell-like and cancer-related gene signatures. Eighty differentially expressed stem cell-related genes were identified in CD133+ cells, where the top pathways include Notch, Notch1-mediated NF-κB, and WNT signaling. Overexpression of growth factor receptors, PI3K/mTOR, and STAT pathway genes and inactivation of genes regulating epigenetic modification of chromatin implicated in cancer were also identified. Verification of these gene signatures was conducted with Nanostring in an independent tumor set. Pharmacologic or genetic modulation of Notch1, IKKα, RELA and RELB modulated NF-κB transactivation, the CD133+ population, and phenotype. Immunofluorescent staining confirmed co-localization of CD133+ and IKKα expression in SCC tumor specimens. Our data support the linkage and importance of non-canonical Notch1 and IKK-mediated NF-κB activation in promoting CD133+ population and TIC phenotype in hcSCC.
Project description:T cell acute lymphoblastic leukemia (T-ALL), unlike other ALL types, is only infrequently associated with chromosomal aberrations, but it was recently shown that the majority of TALL patients carry activating mutations in the NOTCH1 gene. However, the signaling pathways and target genes responsible for Notch1-induced neoplastic transformation remain undefined. We report here that constitutively-active Notch1 activates the NF-κB pathway transcriptionally and via the IκB kinase (IKK) complex, thereby causing increased expression of multiple well-characterized NF-κB target genes in bone marrow hematopoietic stem cells and progenitors. Our observations demonstrate that the NF-κB pathway is highly active in established human T-ALL and that inhibition of the pathway can efficiently restrict tumor growth both in vitro and in vivo. These studies identify NF-κB as one of the major mediators of NOTCH1-induced transformation and suggest that the NF-κB pathway is a potential target of future targeted therapies of T-ALL. Keywords: gene expression analysis, signaling pathway alteration
Project description:MTD project_description Inflammation and decreased stem cell function characterize organism aging, yet the relationship between these factors remains incompletely understood. This study shows that aged hematopoietic stem and progenitor cells exhibit increased ground-stage NF-κB activity, which enhances their responsiveness to undergo differentiation and loss of self-renewal in response to inflammation. The study identifies Rad21/cohesin as a critical mediator of NF-κB signals, by increasing chromatin accessibility of inter-/intra-genic and enhancer regions. Rad21/NF-κB are required for normal differentiation, but limit self-renewal of hematopoietic stem cells (HSCs) during aging and inflammation in an NF-κB dependent manner. HSCs from aged mice fail to downregulate Rad21/cohesin and inflammation/differentiation inducing signals in the resolution phase after acute inflammation. and The inhibition of cohesin/NF-κB is sufficient to revert the hypersensitivity of aged HSPCs to inflammation-induced differentiation. During aging, myeloid-biased HSCs with disrupted and naturally occurring reduced expression of Rad21/cohesin are increasingly selected over lymphoid-biased HSCs. Together, Rad21/cohesin mediated NF-κB signaling limits HSPC function during aging and selects for cohesin deficient HSCs with myeloid skewed differentiation.
Project description:The NF-κB pathway is a critical regulator of the immune system and has been implicated in cellular transformation and tumorigenesis. NF-κB response is regulated by the activation state of the IκB kinase (IKK) complex and triggered by a wide spectrum of stimuli. We previously reported that NF-κB is downstream of Notch1 in T cell acute lymphoblastic leukaemia (T-ALL), however both the mechanisms involving Notch1-induced NF-κB activation and the potential importance of NF-κB in the maintenance of the disease are unknown. Here we visualize Notch-induced NF-κB activation using both human T-ALL cell lines and animal models of this type of leukemia. We show that it is not Notch1 itself but Hes1, a canonical Notch target, the responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by a direct transcriptional repression of the deubiquitinating enzyme CYLD, a well-characterized IKK inhibitor. Consistently, CYLD expression is significantly reduced in primary T-ALL leukemias. Finally, we demonstrate that IKK complex inhibition is a promising option for the targeted therapy of T-ALL as suppression of IKK function affected both the survival of human T-ALL cells in vitro and the maintenance of the disease in vivo. Transcriptional consequences of NF-kB inactivation in human T-ALL1 cell line
Project description:Mesenchymal stem cells (MSCs) are known to induce the conversion of activated T-cells into regulatory T-cells in vitro. The marker CD69 is a target of canonical NF-κB signaling and is transiently expressed upon activation; however, stable CD69 expression defines cells with immunoregulatory properties. Given its enormous therapeutic potential, we explored the molecular mechanisms underlying the induction of regulatory cells by MSCs. Peripheral blood CD3+ T-cells were activated and cultured in the presence or absence of MSCs. CD4+ cell mRNA expression was then characterized by microarray analysis. The drug BAY11-7082 and a siRNA against RELB were used to explore the differential roles of canonical and non-canonical NF-κB signaling, respectively. Flow cytometry and real-time PCR were used for analyses. Genes with immunoregulatory functions, CD69 and non-canonical NF-κB subunits (RELB and NFKB2) were all expressed at higher levels in lymphocytes co-cultured with MSCs. The frequency of CD69+ cells among lymphocytes cultured alone progressively decreased after activation. In contrast, the frequency of CD69+ cells increased significantly following activation in lymphocytes co-cultured with MSCs. Inhibition of canonical NF-κB signaling by BAY immediately following activation blocked the induction of CD69; however, inhibition of canonical NF-κB signaling on the 3rd day further induced the expression of CD69. Furthermore, late expression of CD69 was inhibited by RELB siRNA. These results indicate that the canonical NF-κB pathway controls the early expression of CD69 after activation; however, in an immunoregulatory context, late and sustained CD69 expression is promoted by the non-canonical pathway and is inhibited by canonical NF-κB signaling. In order to study the molecular basis by which Multipotent Mesenchymal Stromal/Stem Cells (MSC) exert their immune regulatory function, immunomagnetically purified CD3+ T-cells from the peripheral blood of 3 individuals were activated and cultured in the presence or absence of MSCs. Following 5 days, CD4+ and CD8+ T-cells were further immunomagnetically selected and their gene expression profiles were obtained by microarrays and compared. Paired samples from 3 individuals were used for this analysis.
Project description:Both EZH2 and NF-κB contribute to aggressive breast cancer, yet whether the two oncogenic factors have functional cross-talk in breast cancer is largely unknown. Here, we uncover an unexpected role of EZH2 in conferring the constitutive activation of NF-κB target gene expression in ER-negative basal-like breast cancer cells. This function of EZH2 is independent of its histone methyltransferase activity but requires the physical interaction with RelA/RelB to promote the expression of NF-κB targets. Intriguingly, EZH2 acts oppositely in repressing NF-κB targets in ER-positive luminal-like breast cancer cells by interacting with ER and directing repressive histone methylation. Thus, EZH2 function as a double-facet molecule in breast cancers, functioning either as a transcriptional activator or repressor of NF-κB targets, in a cell context-dependent manner. These findings reveals an additional mechanism by which EZH2 promotes breast cancer progression and also underscore the need for developing context-specific strategy for therapeutic targeting of EZH2 in breast cancers.
Project description:Full title: Cancer Associated Fibroblasts are activated in incipient neoplasia to orchestrate tumor promoting inflammation in an NF-κB-dependent manner. Cancer Associated Fibroblasts (CAFs) support tumorigenesis by stimulating angiogenesis, cancer cell proliferation, and invasion. We demonstrate that CAFs also mediate tumor-enhancing inflammation. Using a mouse model of squamous skin cancer, we found a pro-inflammatory gene signature in CAFs isolated from dysplastic skin. This signature was also evident in CAFs from skin as well as mammary and pancreatic tumors in mice, and in human cancer. Surprisingly, the inflammatory signature was already activated in CAFs isolated from the incipient hyperplastic stage in multistep tumorigenesis. CAFs from this pathway functioned to promote macrophage recruitment, neovascularization and tumor growth in vivo, activities abolished when NF-κB signaling was inhibited. Additionally, we show that normal dermal fibroblasts can be “educated” by carcinoma cells to express pro-inflammatory genes.
Project description:Cordyceps participates in various pharmacological activities including anti-tumor, and is involved in the regulation of NF-κB signaling pathway. However, the detailed role of cordycepin in suppression of NF-κB signaling pathway is less clear. In this study, we first analyzed the effect of cordyceps on NF-κB activity in TK-10 cells, and found that cordyceps resulted in a dose-dependent reduction in TNF-α-induced NF-κB activation. Here, we show that cordyceps mediated NF-kB inhibition induces apoptosis in TK-10 cells involved the serial activation of caspases. Moreover, we demonstrate that in addition to activating caspases, the cordyceps negatively modulates TNF-α-mediated NF-κB signaling to promote JNK activation, which results in apoptosis, and that NF-kB regulates antiapoptotic factor GADD45b and the JNK kinase MKK7. When the TNFα cytokine binds to the TNF receptor, IκB dissociates from NF-κB. As a result, the active NF-κB translocates to the nucleus. Cordyceps clearly prevented NF-κB from mobilizing to the nucleus, resulting in downregulation of GADD45b, whereas upregulation of MKK7 and phosphorylation of JNK (p-JNK). This increased Bax activation, leading to marked cordyceps-induced apoptosis. Bax subfamily proteins induced apoptosis through caspase-3. Furthermore, siRNA mediated inhibition of MKK7 downregulated p-JNK and The JNK inhibitor SP600125 strongly inhibited Bax. Thus, these results indicate that cordyceps inhibits NF-κB/GADD45b signaling activation to upregulate MKK7-JNK signaling pathway to induce apoptosis in TK-10 cells and support the potential of cordyceps as a therapeutic agent for renal cancer.
Project description:Pro-inflammatory cytokines were shown to promote growth and survival of cancerous cells. TNF induced RelA:p50 NF-κB dimer via the canonical pathway is thought to link inflammation with cancer. Integrating biochemical and computational studies we identify that deficiency of non-canonical signal transducer p100 triggers a positive autoregulatory loop, which instead perpetuates an alternate RelB:p50 containing NF-κB activity upon TNF treatment. TNF stimulated RelB:p50 dimer is sufficient for mediating NF-κB target gene-expressions and suppressing apoptotic cellular death independent of principal NF-κB subunit RelA. We further demonstrate that activating mutations in non-canonical NF-κB module deplete multiple myeloma cells of p100, thereby, provoking autoregulatory RelB:p50 activation. Finally, autoregulatory control reinforces protracted pro-survival NF-κB response, albeit comprising of RelB:p50, upon TNF priming that protects myeloma cells with dysfunctional p100 from subsequent apoptotic insults. In sum, we present evidence for positive autoregulation mediated through the NF-κB system and its potential involvement in human neoplasm.
Project description:In this study, we describe a novel relationship between glioblastoma CSCs and the Notch pathway, which involves the constitutive activation of STAT3 and NF-κB signaling. We demonstrate that adherent glioma CSCs exhibit characteristics previously described for CSCs grown in suspension culture. The expression of CD133, Sox2 and Nestin increased when compared to glioma cells grown in monolayer, and the adherent CSCs were ~100 times more tumorigenic in vivo than monolayer cultured glioma cells. We also found that while the STAT3 and NF-κB signaling pathways are constitutively activated in glioma lines, these pathways are dramatically activated in glioma CSCs. Treatment with STAT3 inhibitors led to a loss of nuclear activation of STAT3 signaling and suppression of growth in both monolayer and CSC conditions. There was a markedly greater growth suppressive effect on glioma CSCs, suggesting that targeted therapy of these key pathways in glioma CSCs may be possible. To further investigate potential biomarkers in glioma CSCs, microarray analysis was performed and revealed deregulation of the Notch signaling pathway. This constitutive activation of STAT3, NF-κB, and Notch pathways in glioma CSCs helps identify novel therapeutic targets for the treatment of glioma. GBM6 cells were continuously maintained as subcutaneous xenografts in NSG mice, and monolayer and CSC cultures were derived from freshly harvested tumor tissue. A total of 6 samples were subjected to microarray analysis, with three biological replicates for each experimental condition.