Metabolic reprogramming of cancer-associated fibroblasts by TGF-β drives tumor growth: Connecting TGF-β signaling with “Warburg-like” cancer metabolism and L-lactate production

We have previously shown that a loss of stromal Cav-1 is a biomarker of poor prognosis in breast cancers. Mechanistically, a loss of Cav-1 induces the metabolic reprogramming of stromal cells, with increased autophagy/mitophagy, mitochondrial dysfunction and aerobic glycolysis. As a consequence, Cav-1-low CAFs generate nutrients (such as L-lactate) and chemical building blocks that fuel mitochondrial metabolism and the anabolic growth of adjacent breast cancer cells. It is also known that a loss of Cav-1 is associated with hyperactive TGF-β signaling. However, it remains unknown whether hyperactivation of the TGF-β signaling pathway contributes to the metabolic reprogramming of Cav-1-low CAFs. To address these issues, we overexpressed TGF-β ligands and the TGF-β receptor I (TGFβ-RI) in stromal fibroblasts and breast cancer cells. Here, we show that the role of TGF-β in tumorigenesis is compartment-specific, and that TGF-β promotes tumorigenesis by shifting cancer-associated fibroblasts toward catabolic metabolism. Importantly, the tumor-promoting effects of TGF-β are independent of the cell type generating TGF-β. Thus, stromal-derived TGF-β activates signaling in stromal cells in an autocrine fashion, leading to fibroblast activation, as judged by increased expression of myofibroblast markers, and metabolic reprogramming, with a shift toward catabolic metabolism and oxidative stress. We also show that TGF-β-activated fibroblasts promote the mitochondrial activity of adjacent cancer cells, and in a xenograft model, enhancing the growth of breast cancer cells, independently of angiogenesis. Conversely, activation of the TGF-β pathway in cancer cells does not influence tumor growth, but cancer cell-derived-TGF-β ligands affect stromal cells in a paracrine fashion, leading to fibroblast activation and enhanced tumor growth. In conclusion, ligand-dependent or cell-autonomous activation of the TGF-β pathway in stromal cells induces their metabolic reprogramming, with increased oxidative stress, autophagy/mitophagy and glycolysis, and downregulation of Cav-1. These metabolic alterations can spread among neighboring fibroblasts and greatly sustain the growth of breast cancer cells. Our data provide novel insights into the role of the TGF-β pathway in breast tumorigenesis, and establish a clear causative link between the tumor-promoting effects of TGF-β signaling and the metabolic reprogramming of the tumor microenvironment.     

In vitro effect of indomethacin and interferon-alpha on Th1 and Th2 cytokine synthesis in patients with chronic hepatitis C

Current evidences suggest that non-steroidal anti-inflammatory drugs could enhance the antiviral activity of interferon-alpha in chronic HCV infection. In this study, we investigated the effect of indomethacin, a non-steroidal anti-inflammatory drug, and interferon-alpha on cytokine production by peripheral blood mononuclear cells from 12 untreated patients with chronic hepatitis C. We evaluated the effect of incubation with indomethacin, interferon-alpha or both on synthesis of Th1- (interleukin-2, interferon-gamma) and Th2-associated cytokines (interleukin-4, interleukin-10), and of the antiviral protein 2',5'-oligoadenylate synthetase. Interferon-alpha induced a significant increase in production of interleukin-2. Smaller increases were also seen in the presence of indomethacin, while incubation with both indomethacin and interferon-alpha leads to a synergistic effect. Incubation with indomethacin decreased both interleukin-4 and interleukin-10, whereas interferon-alpha increased these cytokines. The addition of indomethacin to interferon-alpha significantly reversed this interferon-induced increase. Finally, both indomethacin and the association interferon-alpha plus indomethacin determined a significant increase in 2',5'-oligoadenylate synthetase production compared to both baseline and interferon-alpha alone. In conclusion, indomethacin was able to enhance the antiviral activity of interferon-alpha and to modulate the interferon-induced Th1 and Th2 cytokine response by increasing the Th1-response, fundamental for sustained clearance of HCV, and by decreasing the Th-2 type response, associated with HCV persistence.     

Chemo-enzymatic preparation of resveratrol derivatives

Regioselective derivatisation of resveratrol (1) at positions 3, 5 or 4′ was achieved by a chemo-enzymatic procedure based on standard chemical reactions and esterification or alcoholysis in organic solvents catalysed by the commercially available Pseudomonas cepacia (PcL) and Candida antarctica (CaL) lipases.     

Functional heterogeneity of GEF-free initiation factor 2 purified from suckling and adult rat brain

The functional behavior of initiation factor 2 was studied in purified preparations from the brains of suckling (4-12-day-old) and adult (60-day-old) rats. Adult eIF2 has lower GDP and GTP affinity than suckling eIF2, even in the presence of a large excess of GTP, whereas suckling eIF2 has a lower capacity to bind GTP. Since these two factors are free of guanine nucleotide exchange factor (GEF), and ribosomal fractions show an age-dependent difference in GEF activity, the observed functional heterogeneity may be due to a different ratio in eIF2 species (eIF2-GDP, eIF2(P)).

Developing brain Protein synthesis Initiation factor 2 Guanine nucleotide exchange factor     

DNA elements modulating the <Emphasis Type="Italic">KARS12</Emphasis> chromosomal replicator in <Emphasis Type="Italic">Kluyveromyces lactis</Emphasis>

Eukaryotic chromosomal DNA replication is initiated by a highly conserved set of proteins that interact with cis-acting elements on chromosomes called replicators. Despite the conservation of replication initiation proteins, replicator sequences show little similarity from species to species in the small number of organisms that have been examined. Examination of replicators in other species is likely to reveal common features of replicators. We have examined a Kluyeromyces lactis replicator, KARS12, that functions as origin of DNA replication on plasmids and in the chromosome. It contains a 50-bp region with similarity to two other K. lactis replicators, KARS101 and the pKD1 replication origin. Replacement of the 50-bp sequence with an EcoRI site completely abrogated the ability of KARS12 to support plasmid and chromosomal DNA replication origin activity, demonstrating this sequence is a common feature of K. lactis replicators and is essential for function, possibly as the initiator protein binding site. Additional sequences up to 1 kb in length are required for efficient KARS12 function. Within these sequences are a binding site for a global regulator, Abf1p, and a region of bent DNA, both of which contribute to the activity of KARS12. These elements may facilitate protein binding, protein/protein interaction and/or nucleosome positioning as has been proposed for other eukaryotic origins of DNA replication.     

The DNA damage response pathway contributes to the stability of chromosome III derivatives lacking efficient replicators

In eukaryotic chromosomes, DNA replication initiates at multiple origins. Large inter-origin gaps arise when several adjacent origins fail to fire. Little is known about how cells cope with this situation. We created a derivative of Saccharomyces cerevisiae chromosome III lacking all efficient origins, the 5ORIΔ-ΔR fragment, as a model for chromosomes with large inter-origin gaps. We used this construct in a modified synthetic genetic array screen to identify genes whose products facilitate replication of long inter-origin gaps. Genes identified are enriched in components of the DNA damage and replication stress signaling pathways. Mrc1p is activated by replication stress and mediates transduction of the replication stress signal to downstream proteins; however, the response-defective mrc1(AQ) allele did not affect 5ORIΔ-ΔR fragment maintenance, indicating that this pathway does not contribute to its stability. Deletions of genes encoding the DNA-damage-specific mediator, Rad9p, and several components shared between the two signaling pathways preferentially destabilized the 5ORIΔ-ΔR fragment, implicating the DNA damage response pathway in its maintenance. We found unexpected differences between contributions of components of the DNA damage response pathway to maintenance of ORIΔ chromosome derivatives and their contributions to DNA repair. Of the effector kinases encoded by RAD53 and CHK1, Chk1p appears to be more important in wild-type cells for reducing chromosomal instability caused by origin depletion, while Rad53p becomes important in the absence of Chk1p. In contrast, RAD53 plays a more important role than CHK1 in cell survival and replication fork stability following treatment with DNA damaging agents and hydroxyurea. Maintenance of ORIΔ chromosomes does not depend on homologous recombination. These observations suggest that a DNA-damage-independent mechanism enhances ORIΔ chromosome stability. Thus, components of the DNA damage response pathway contribute to genome stability, not simply by detecting and responding to DNA template damage, but also by facilitating replication of large inter-origin gaps.     

Impact assessment in SLCA: sorting the sLCIA methods according to their outcomes

Background, aims, and scope  

Social Life Cycle Assessment (SLCA) is a tool assessing the social aspects of products and services. This article is a step forward from the Guidelines and wishes to clarify the different impact assessment (IA) methods covered in the Guidelines and how these different methods would provide different types of information regarding the social aspects of the product system.     

The G Protein regulators EGL-10 and EAT-16, the G<Subscript>i</Subscript>α GOA-1 and the G<Subscript>q</Subscript>α EGL-30 modulate the response of the <Emphasis Type="Italic">C. elegans</Emphasis>ASH polymodal nociceptive sensory neurons to repellents

Background  

Polymodal, nociceptive sensory neurons are key cellular elements of the way animals sense aversive and painful stimuli. In Caenorhabditis elegans, the polymodal nociceptive ASH sensory neurons detect aversive stimuli and release glutamate to generate avoidance responses. They are thus useful models for the nociceptive neurons of mammals. While several molecules affecting signal generation and transduction in ASH have been identified, less is known about transmission of the signal from ASH to downstream neurons and about the molecules involved in its modulation.     

Catalytic hydration of cyanopyridines using nickel(0)

The homogeneous catalytic hydration of 2-, 3- and 4-cyanopyridines using 0.5 mol% of [(dippe)Ni(μ-H)]₂ as catalyst precursor was achieved under heating. In the case of 4-cyanopyridine, production of isonicotinamide was observed at temperatures in the range of 80-120 °C. Heating to 180 °C resulted in formation of isonicotinic acid. In the case of 2- and 3-cyanopyridines the quantitative formation of their corresponding amides was achieved at 100 °C. The catalytic hydration of 2,6-dicyanopyridine was also undertaken in this work, in its case resulting in the synthesis of the mixed cyano/amide product, 2-cyanopyridine-6-carboxamide, at short reaction times.