Notch Signaling Regulates Mitochondrial Metabolism and NF-κB Activity in Triple-Negative Breast Cancer Cells via IKKα-Dependent Non-canonical Pathways

Triple negative breast cancer (TNBC) patients have high risk of recurrence and metastasis, and current treatment options remain limited. Cancer stem-like cells (CSCs) have been linked to cancer initiation, progression and chemotherapy resistance. Notch signaling is a key pathway regulating TNBC CSC survival. Treatment of TNBC with PI3K or mTORC1/2 inhibitors results in drug-resistant, Notch-dependent CSC. However, downstream mechanisms and potentially druggable Notch effectors in TNBC CSCs are largely unknown. We studied the role of the AKT pathway and mitochondrial metabolism downstream of Notch signaling in TNBC CSC from cell lines representative of different TNBC molecular subtypes as well as a novel patient-derived model. We demonstrate that exposure of TNBC cells to recombinant Notch ligand Jagged1 leads to rapid AKT phosphorylation in a Notch1-dependent but RBP-Jκ independent fashion. This requires mTOR and IKKα. Jagged1 also stimulates mitochondrial respiration and fermentation in an AKT- and IKK-dependent fashion. Notch1 co-localizes with mitochondria in TNBC cells. Pharmacological inhibition of Notch cleavage by gamma secretase inhibitor PF-03084014 in combination with AKT inhibitor MK-2206 or IKK-targeted NF-κB inhibitor Bay11-7082 blocks secondary mammosphere formation from sorted CD90hi or CD44+CD24low (CSCs) cells. A TNBC patient-derived model gave comparable results. Besides mitochondrial oxidative metabolism, Jagged1 also triggers nuclear, NF-κB-dependent transcription of anti-apoptotic gene cIAP-2. This requires recruitment of Notch1, IKKα and NF-κB to the cIAP-2 promoter. Our observations support a model where Jagged1 triggers IKKα-dependent, mitochondrial and nuclear Notch1 signals that stimulate AKT phosphorylation, oxidative metabolism and transcription of survival genes in PTEN wild-type TNBC cells. These data suggest that combination treatments targeting the intersection of the Notch, AKT and NF-κB pathways have potential therapeutic applications against CSCs in TNBC cases with Notch1 and wild-type PTEN expression

Neighborhood Social Determinants of Triple Negative Breast Cancer

Triple Negative Breast Cancer (TNBC) is an aggressive, heterogeneous subtype of breast cancer, which is more frequently diagnosed in African American (AA) women than in European American (EA) women. The purpose of this study is to investigate the role of social determinants in racial disparities in TNBC. Data on Louisiana TNBC patients diagnosed in 2010–2012 were collected and geocoded to census tract of residence at diagnosis by the Louisiana Tumor Registry. Using multilevel statistical models, we analyzed the role of neighborhood concentrated disadvantage index (CDI), a robust measure of physical and social environment, in racial disparities in TNBC incidence, stage at diagnosis, and stage-specific survival for the study population. Controlling for age, we found that AA women had a 2.21 times the incidence of TNBC incidence compared to EA women. Interestingly, the incidence of TNBC was independent of neighborhood CDI and adjusting for neighborhood environment did not impact the observed racial disparity. AA women were more likely to be diagnosed at later stages and CDI was associated with more advanced stages of TNBC at diagnosis. CDI was also significantly associated with poorer stage-specific survival. Overall, our results suggest that neighborhood disadvantage contributes to racial disparities in stage at diagnosis and survival among TNBC patients, but not to disparities in incidence of the disease. Further research is needed to determine the mechanisms through which social determinants affect the promotion and progression of this disease and guide efforts to improve overall survival

Obesity Modulates the Gut Microbiome in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive, molecularly heterogeneous subtype of breast cancer. Obesity is associated with increased incidence and worse prognosis in TNBC through various potential mechanisms. Recent evidence suggests that the gut microbiome plays a central role in the progression of cancer, and that imbalances or dysbiosis in the population of commensal microbiota can lead to inflammation and contribute to tumor progression. Obesity is characterized by low-grade inflammation, and gut dysbiosis is associated with obesity, chronic inflammation, and failure of cancer immunotherapy. However, the debate on what constitutes a “healthy” gut microbiome is ongoing, and the connection among the gut microbiome, obesity, and TNBC has not yet been addressed. This study aims to characterize the role of obesity in modulating the gut microbiome in a syngeneic mouse model of TNBC. 16S rRNA sequencing and metagenomic analyses were performed to analyze and annotate genus and taxonomic profiles. Our results suggest that obesity decreases alpha diversity in the gut microbiome. Metagenomic analysis revealed that obesity was the only significant factor explaining the similarity of the bacterial communities according to their taxonomic profiles. In contrast to the analysis of taxonomic profiles, the analysis of variation of functional profiles suggested that obesity status, tumor presence, and the obesity–tumor interaction were significant in explaining the variation of profiles, with obesity having the strongest correlation. The presence of tumor modified the profiles to a greater extent in obese than in lean animals. Further research is warranted to understand the impact of the gut microbiome on TNBC progression and immunotherapy

Dna Demethylation Of Human Mesenchymal Stem Cells Has Increased Potential To Become Neuronal Cells

The multipotent nature of human mesenchymal stem cells (hMSCs) is limited by their tissue-specific character. Epigenetic modifications of stem cell lineage are necessary to overcome this barrier. We demonstrated that treatment of hMSCs with DNA demethylating agent, 5-aza-deoxycytidine induced expression of Nestin, an intermediate filament protein, and also up regulated the expression of Brain-derived neurotrophic factor (BDNF) receptor, TrkB. When these cells were co-cultured with differentiated human neural stem cells, a sub-population of hMSCs differentiated into neural cells resembling neuronal morphology. BDNF induced the phosphorylation of extracellular signal-regulated kinases (ERKs) and cAMP response element binding (CREB) protein by MAP Kinase dependent manner in 5-aza-deoxycytidine treated hMSCs. BDNF also induced the expression of βIII-tubulin protein. We concluded that changing the DNA methylation status of genome and BDNF are important for neural differentiation of hMSCs. Our findings suggested that treatment with DNA demethylation agent, 5-aza-deoxycytidine increased the multipotency of hMSCs. © 2012 by Nova Science Publishers, Inc. All rights reserved

Dna Demethylation Of Human Mesenchymal Stem Cells Has Increased Potential To Become Neuronal Cells

The multipotent nature of human mesenchymal stem cells (hMSCs) is limited by their tissue-specific character. Epigenetic modifications of stem cell lineage are necessary to overcome this barrier. We demonstrated that treatment of hMSCs with DNA demethylating agent, 5-aza-deoxycytidine induced expression of Nestin, an intermediate filament protein, and also up regulated the expression of Brain-derived neurotrophic factor (BDNF) receptor, TrkB. When these cells were co-cultured with differentiated human neural stem cells, a sub-population of hMSCs differentiated into neural cells resembling neuronal morphology. BDNF induced the phosphorylation of extracellular signal-regulated kinases (ERKs) and cAMP response element binding (CREB) protein by MAP Kinase dependent manner in 5-aza-deoxycytidine treated hMSCs. BDNF also induced the expression of βIII-tubulin protein. We concluded that changing the DNA methylation status of genome and BDNF are important for neural differentiation of hMSCs. Our findings suggested that treatment with DNA demethylation agent, 5-aza-deoxycytidine increased the multipotency of hMSCs. © 2008 Nova Science Publishers, Inc

Notch Signaling in Myeloid Cells as a Regulator of Tumor Immune Responses

Cancer immunotherapy, which stimulates or augments host immune responses to treat malignancies, is the latest development in the rapidly advancing field of cancer immunology. The basic principles of immunotherapies are either to enhance the functions of specific components of the immune system or to neutralize immune-suppressive signals produced by cancer cells or tumor microenvironment cells. When successful, these approaches translate into long-term survival for patients. However, durable responses are only seen in a subset of patients and so far, only in some cancer types. As for other cancer treatments, resistance to immunotherapy can also develop. Numerous research groups are trying to understand why immunotherapy is effective in some patients but not others and to develop strategies to enhance the effectiveness of immunotherapy. The Notch signaling pathway is involved in many aspects of tumor biology, from angiogenesis to cancer stem cell maintenance to tumor immunity. The role of Notch in the development and modulation of the immune response is complex, involving an intricate crosstalk between antigen-presenting cells, T-cell subpopulations, cancer cells, and other components of the tumor microenvironment. Elegant studies have shown that Notch is a central mediator of tumor-induced T-cell anergy and that activation of Notch1 in CD8 T-cells enhances cancer immunotherapy. Tumor-infiltrating myeloid cells, including myeloid-derived suppressor cells, altered dendritic cells, and tumor-associated macrophages along with regulatory T cells, are major obstacles to the development of successful cancer immunotherapies. In this article, we focus on the roles of Notch signaling in modulating tumor-infiltrating myeloid cells and discuss implications for therapeutic strategies that modulate Notch signaling to enhance cancer immunotherapy

H₂S Prodrug, SG-1002, Protects against Myocardial Oxidative Damage and Hypertrophy In Vitro via Induction of Cystathionine β-Synthase and Antioxidant Proteins

Endogenously produced hydrogen sulfide (H2S) is critical for cardiovascular homeostasis. Therapeutic strategies aimed at increasing H2S levels have proven cardioprotective in models of acute myocardial infarction (MI) and heart failure (HF). The present study was undertaken to investigate the effects of a novel H2S prodrug, SG-1002, on stress induced hypertrophic signaling in murine HL-1 cardiac muscle cells. Treatment of HL-1 cells with SG-1002 under serum starvation without or with H2O2 increased the levels of H2S, H2S producing enzyme, and cystathionine β-synthase (CBS), as well as antioxidant protein levels, such as super oxide dismutase1 (SOD1) and catalase, and additionally decreased oxidative stress. SG-1002 also decreased the expression of hypertrophic/HF protein markers such as atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), galectin-3, TIMP1, collagen type III, and TGF-β1 in stressed HL-1 cells. Treatment with SG-1002 caused a significant induction of cell viability and a marked reduction of cellular cytotoxicity in HL-1 cells under serum starvation incubated without or with H2O2. Experimental results of this study suggest that SG-1002 attenuates myocardial cellular oxidative damage and/or hypertrophic signaling via increasing H2S levels or H2S producing enzymes, CBS, and antioxidant proteins

Cigarette Smoke Alters the Hematopoietic Stem Cell Niche

Effects of tobacco smoke on hematologic derangements have received little attention. This study employed a mouse model of cigarette smoke exposure to explore the effects on bone marrow niche function. While lung cancer is the most widely studied consequence of tobacco smoke exposure, other malignancies, including leukemia, are associated with tobacco smoke exposure. Animals received cigarette smoke exposure for 6 h/day, 5 days/week for 9 months. Results reveal that the hematopoietic stem and progenitor cell (HSPC) pool size is reduced by cigarette smoke exposure. We next examined the effect of cigarette smoke exposure on one supporting cell type of the niche, the mesenchymal stromal cells (MSCs). Smoke exposure decreased the number of MSCs. Transplantation of naïve HSPCs into irradiated mice with cigarette smoke exposure yielded fewer numbers of engrafted HSPCs. This result suggests that smoke-exposed mice possess dysfunctional niches, resulting in abnormal hematopoiesis. Co-culture experiments using MSCs isolated from control or cigarette smoke-exposed mice with naïve HSPCs in vitro showed that MSCs from cigarette smoke-exposed mice generated marked expansion of naïve HSPCs. These data show that cigarette smoke exposure decreases in vivo MSC and HSC number and also increases pro-proliferative gene expression by cigarette smoke-exposed MSCs, which may stimulate HSPC expansion. These results of this investigation are clinically relevant to both bone marrow donors with a history of smoking and bone marrow transplant (BMT) recipients with a history of smoking

Evaluation of bioactivities of methanol and petroleum ether extracts of Cassia renigera seed

Abstract Background To investigate in vitro antioxidant, brine shrimp lethality bioassay, antimicrobial, anthelmintic activities and in vivo peripheral analgesic activity of methanol and petroleum ether extracts of Cassia renigera seed. Methods Phytochemical screening of the crude extracts was carried out. Antioxidant activity was determined using seven different methods. Brine shrimp lethality bioassay and anthelmintic activities were done using nauplii of Artemia salina and adult earthworm (Pheretima posthuma), respectively. The antimicrobial potential was investigated against three Gram-positive and three Gram-negative bacteria. Acetic acid induced writhing test was performed to evaluate peripheral analgesic activity. Results Both methanol and petroleum ether extracts showed the presence of flavonoids, saponins, and tannins. While alkaloids, glycosides, and steroids were only found in the methanolic extract. Methanolic extract showed more potent 1,1- diphenyl-2-picrylhydrazyl (DPPH), nitric oxide scavenging capacity, cupric reducing and reducing power capacity than petroleum ether extract. While petroleum ether extract showed better results in total phenol and total antioxidant activities. In brine shrimp lethality bioassay methanolic and petroleum ether extracts showed the LC50 value of 74.44 and 121.49 μg/mL, respectively. In overall antimicrobial study methanolic extract showed better activity than petroleum ether extract. Methanolic extract of 50 mg/mL showed maximum anthelmintic activity comparable to the standard (Piperazine Citrate, 10 mg/mL). Both 500 mg/kg and 1000 mg/kg body weight dose of the methanolic extract exhibited significant 39.64% and 58.73% writhing inhibition (푃< 0.05) in test animals, consecutively. Conclusions In a nutshell, the results suggested that the seed can be used as a potential source for the aforesaid bioactivities