bims-stacyt 2019-08-18 papers

Physiol Rev. 2019 Aug 15.

Immunity, Hypoxia and Metabolism - the ménage à trois of cancer: implications for immunotherapy.

Carla Riera-Domingo, Annette Audigé, Sara Granja, Wan-Chen Cheng, Ping-Chih Ho, Fátima Baltazar, Christian Stockmann, Massimiliano Mazzone.

It is generally accepted that metabolism is able to shape the immune response. Only recently we are gaining awareness that the metabolic crosstalk between different tumor compartments strongly contributes to the harsh tumor microenvironment (TME) and ultimately impairs immune cell fitness and effector functions. The major aims of this review are: i) to provide an overview on the immune system in cancer; ii) to position oxygen shortage and metabolic competition as the ground of a restrictive TME and as important players in the anti-tumor immune response; iii) to define how immunotherapies affect hypoxia/oxygen-delivery and the metabolic landscape of the tumor and iv) vice versa, how oxygen and metabolites within the TME impinge on the success of immunotherapies. By analyzing preclinical and clinical endeavors, we will discuss how a metabolic characterization of the TME can identify novel targets and signatures that could be exploited in combination with standard immunotherapies and can help to predict the benefit of new and traditional immunotherapeutic drugs.

Keywords: Cancer; Hypoxia; Immunity; Immunotherapy; Metabolism

DOI: https://doi.org/10.1152/physrev.00018.2019

J Cell Biochem. 2019 Aug 12.

Hypoxia alters the release and size distribution of extracellular vesicles in pancreatic cancer cells to support their adaptive survival.

Mary C Patton, Haseeb Zubair, Mohammad Aslam Khan, Seema Singh, Ajay P Singh.

Pancreatic tumors are highly desmoplastic and poorly-vascularized, and therefore must develop adaptive mechanisms to sustain their survival under hypoxic condition. Extracellular vesicles (EV) play vital roles in pancreatic tumor pathobiology by facilitating intercellular communication. Here we studied the effect of hypoxia on the release of EVs and examined their role in adaptive survival of pancreatic cancer (PC) cells. Hypoxia promoted the release of EV in PC cell lines, MiaPaCa and AsPC1, wherein former exhibited a far greater induction. Moreover, a time-dependent, measurable and significant increase was recorded for small EV (SEV) in both the cell lines with only minimal induction observed for medium (MEV) and large EVs (LEV). Similarly, noticeable changes in size distribution of SEV were also recorded with a shift toward smaller average size under extreme hypoxia. Thrombospondin (apoptotic bodies marker) was exclusively detected on LEVs, while Arf6 (microvesicles marker) was mostly present on MEV with some expression in LEV as well. However, CD9 and CD63 (exosome markers) were expressed in both SEV and MEVs with a decreased expression recorded under hypoxia. Among all subfractions, SEV was the most bioactive in promoting the survival of hypoxic PC cells and hypoxia-inducible factor-1α stabilization was involved in heightened EV release under hypoxia and for their potency to promote hypoxic cell survival. Altogether, our findings provide a novel mechanism for the adaptive hypoxic survival of PC cells and should serve as the basis for future investigations on broader functional implications of EV.

Keywords: HIF-1α; exosomes; extracellular vesicles; hypoxia; pancreatic cancer; tumor microenvironment

DOI: https://doi.org/10.1002/jcb.29328

Br J Cancer. 2019 Aug 16.

Acidity promotes tumour progression by altering macrophage phenotype in prostate cancer.

Asmaa El-Kenawi, Chandler Gatenbee, Mark Robertson-Tessi, Rafael Bravo, Jasreman Dhillon, Yoganand Balagurunathan, Anders Berglund, Naveen Visvakarma, Arig Ibrahim-Hashim, Jung Choi, Kimberly Luddy, Robert Gatenby, Shari Pilon-Thomas, Alexander Anderson, Brian Ruffell, Robert Gillies.

BACKGROUND: Tumours rapidly ferment glucose to lactic acid even in the presence of oxygen, and coupling high glycolysis with poor perfusion leads to extracellular acidification. We hypothesise that acidity, independent from lactate, can augment the pro-tumour phenotype of macrophages.
METHODS: We analysed publicly available data of human prostate cancer for linear correlation between macrophage markers and glycolysis genes. We used zwitterionic buffers to adjust the pH in series of in vitro experiments. We then utilised subcutaneous and transgenic tumour models developed in C57BL/6 mice as well as computer simulations to correlate tumour progression with macrophage infiltration and to delineate role of acidity.
RESULTS: Activating macrophages at pH 6.8 in vitro enhanced an IL-4-driven phenotype as measured by gene expression, cytokine profiling, and functional assays. These results were recapitulated in vivo wherein neutralising intratumoural acidity reduced the pro-tumour phenotype of macrophages, while also decreasing tumour incidence and invasion in the TRAMP model of prostate cancer. These results were recapitulated using an in silico mathematical model that simulate macrophage responses to environmental signals. By turning off acid-induced cellular responses, our in silico mathematical modelling shows that acid-resistant macrophages can limit tumour progression.
CONCLUSIONS: This study suggests that tumour acidity contributes to prostate carcinogenesis by altering the state of macrophage activation.

DOI: https://doi.org/10.1038/s41416-019-0542-2

PLoS One. 2019 ;14(8): e0220577

Hyperglycemia acts in synergy with hypoxia to maintain the pro-inflammatory phenotype of macrophages.

Mangesh Morey, Peadar O'Gaora, Abhay Pandit, Christophe Hélary.

Diabetic foot ulcers (DFUs) are characterized by a chronic inflammation state which prevents cutaneous wound healing, and DFUs eventually lead to infection and leg amputation. Macrophages located in DFUs are locked in an pro-inflammatory phenotype. In this study, the effect of hyperglycemia and hypoxia on the macrophage phenotype was analyzed. For this purpose, a microarray was performed to study the gene expression profile of macrophages cultivated in a high glucose concentration. Hyperglycemia upregulated the expression of pro-inflammatory cytokines such as TNF-α, IL-1, IL-6, chemokines and downregulated the expression of two receptors involved in phagocytosis (CD 36 and Class B scavenger type I receptors). In addition, eleven anti-apoptotic factors were upregulated whereas three pro-apoptotic genes were downregulated. Subsequently, the contribution of hypoxia and hyperglycemia to chronic inflammation and their potential synergistic effect was evaluated on activated THP-1 derived macrophages. A long term post activation effect (17 hours) was only observed on the upregulation of pro-inflammatory cytokines when hypoxia was combined with a high glucose concentration. In contrast, hyperglycemia and hypoxia did not have any effect on wound healing molecules such as TGF-β1. Taken together, the results show that hyperglycemia acts in synergy with hypoxia to maintain a chronic inflammation state in macrophages.

DOI: https://doi.org/10.1371/journal.pone.0220577

Front Immunol. 2019 ;10 1720

NAD-Biosynthetic and Consuming Enzymes as Central Players of Metabolic Regulation of Innate and Adaptive Immune Responses in Cancer.

Valentina Audrito, Antonella Managò, Federica Gaudino, Leonardo Sorci, Vincenzo Gianluca Messana, Nadia Raffaelli, Silvia Deaglio.

Cancer cells, particularly in solid tumors, are surrounded by non-neoplastic elements, including endothelial and stromal cells, as well as cells of immune origin, which can support tumor growth by providing the right conditions. On the other hand, local hypoxia, and lack of nutrients induce tumor cells to reprogram their metabolism in order to survive, proliferate, and disseminate: the same conditions are also responsible for building a tumor-suppressive microenvironment. In addition to tumor cells, it is now well-recognized that metabolic rewiring occurs in all cellular components of the tumor microenvironment, affecting epigenetic regulation of gene expression and influencing differentiation/proliferation decisions of these cells. Nicotinamide adenine dinucleotide (NAD) is an essential co-factor for energy transduction in metabolic processes. It is also a key component of signaling pathways, through the regulation of NAD-consuming enzymes, including sirtuins and PARPs, which can affect DNA plasticity and accessibility. In addition, both NAD-biosynthetic and NAD-consuming enzymes can be present in the extracellular environment, adding a new layer of complexity to the system. In this review we will discuss the role of the "NADome" in the metabolic cross-talk between cancer and infiltrating immune cells, contributing to cancer growth and immune evasion, with an eye to therapeutic implications.

Keywords: NAD; immune cell regulation; immunometabolism; metabolic reprogramming; tumor microenvironment

DOI: https://doi.org/10.3389/fimmu.2019.01720