bims-stacyt Biomed News
on Paracrine crosstalk between cancer and the organism
Issue of 2019‒05‒12
eight papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. Neuromolecular Med. 2019 May 10.
    Nalamolu KR, Venkatesh I, Mohandass A, Klopfenstein JD, Pinson DM, Wang DZ, Kunamneni A, Veeravalli KK.
      Emerging stroke literature suggests that treatment of experimentally induced stroke with stem cells offered post-stroke neuroprotection via exosomes produced by these cells. Treatment with exosomes has great potential to overcome the limitations associated with cell-based therapies. However, in our preliminary studies, we noticed that the exosomes released from human umbilical cord blood-derived mesenchymal stem cells (MSCs) under standard culture conditions did not improve the post-stroke neurological outcome. Because of this apparent discrepancy, we hypothesized that exosome characteristics vary with the conditions of their production. Specifically, we suggest that the exosomes produced from the cocultures of regular and oxygen-glucose-deprived (OGD) MSCs in vitro would represent the exosomes produced from MSCs that are exposed to ischemic brain cells in vivo, and offer similar therapeutic benefits that the cell treatment would provide. We tested the efficacy of therapy with exosomes secreted from human umbilical cord blood (HUCB)-derived MSCs under in vitro hypoxic conditions on post-stroke brain damage and neurological outcome in a rat model of transient focal cerebral ischemia. We performed the TTC staining procedure as well as the neurological tests including the modified neurological severity scores (mNSS), the modified adhesive removal (sticky-tape), and the beam walking tests before ischemia and at regular intervals until 7 days reperfusion. Treatment with exosomes obtained from the cocultures of normal and OGD-induced MSCs reduced the infarct size and ipsilateral hemisphere swelling, preserved the neurological function, and facilitated the recovery of stroke-induced rats. Based on the results, we conclude that the treatment with exosomes secreted from MSCs at appropriate experimental conditions attenuates the post-stroke brain damage and improves the neurological outcome.
    Keywords:  Brain damage; Exosomes; Ischemia; Neurological recovery; Reperfusion; Stem cells
  2. Mol Oncol. 2019 May 07.
    Jacobsson H, Harrison H, Hughes É, Persson E, Rhost S, Fitzpatrick P, Gustafsson A, Andersson D, Gregersson P, Magnusson Y, Ståhlberg A, Landberg G.
      It is well known that tumor cells are dependent on communication with the tumor microenvironment. Previously, it has been shown that hypoxia induces pronounced, diverse and direct effects on cancer stem cell (CSC) qualities in different breast cancer subtypes. Here, we describe the mechanism by which hypoxia-induced secretion influence CSC spreading. Conditioned media from estrogen receptor (ER)-α positive hypoxic breast cancer cell cultures increased the fraction of CSCs compared to normal growth conditions, as determined using sets of CSC assays and model systems. In contrast, media from ERα-negative hypoxic cell cultures instead decreased this key subpopulation of cancer cells. Further, there was a striking overrepresentation of JAK-STAT-associated cytokines in both the ERα-positive and ERα-negative linked hypoxic responses as determined by a protein screen of the conditioned media. JAK-STAT inhibitors and knockdown experiments further supported the hypothesis that this pathway is critical for the CSC activating and inactivating effects induced by hypoxic secretion. We also observed that the interleukin (IL)-6 -JAK2-STAT3 axis was specifically central for the ERα-negative hypoxic behaviour. Our results underline the importance of considering breast cancer subtypes in treatments targeting JAK-STAT or hypoxia-associated processes, and indicate that hypoxia is not only a confined tumor biological event, but also influences key tumor properties in widespread normoxic microenvironments. This article is protected by copyright. All rights reserved.
    Keywords:  Cancer stem cells; IL-12; IL6; JAK-STAT; breast cancer; hypoxia; secretion
  3. J Hepatol. 2019 May 06. pii: S0168-8278(19)30268-5. [Epub ahead of print]
    Chen DP, Ning WR, Jiang ZZ, Peng ZP, Zhu LY, Zhuang SM, Kuang DM, Zheng L, Wu Y.
      BACKGROUND: & Aims: PD-L1 expression on antigen-presenting cells (APCs) is essential for T cell impairment, and PD-L1-expressing macrophages may mechanistically shape and therapeutically predict the clinical efficacy of PD-L1/PD-1 blockade. Despite the clinical success fostered by immune checkpoint inhibitors, the mechanisms underlying PD-L1 upregulation in human tumor microenvironments remain an enigma.METHODS: Monocytes/macrophages were purified from peripheral blood, non-tumor, or paired tumor tissues of patients with hepatocellular carcinoma (HCC), and their possible glycolytic switch was evaluated. The underlying regulatory mechanisms and clinical significance of specific metabolic switch in these cells were studied with both ex vivo analyses and in vitro experiments.
    RESULTS: We found that monocytes significantly enhanced the levels of glycolysis at the peritumoral region of human HCC. The activation of glycolysis induced PD-L1 expression on these cells and subsequently attenuated CTL responses in tumor tissues. Mechanistically, tumor-derived soluble factors, including hyaluronan fragments, induced the upregulation of a key glycolytic enzyme, PFKFB3, in tumor-associated monocytes. This enzyme not only modulated the cellular metabolic switch but also mediated the increased expression of PD-L1 by activating the NF-κB signaling pathway in these cells. Consistently, the levels of PFKFB3+CD68+ cell infiltration in peritumoral tissues were negatively correlated with overall survival and could serve as an independent prognostic factor for the survival of patients with HCC.
    CONCLUSIONS: Our results reveal a mechanism by which the cellular metabolic switch regulates the pro-tumor functions of monocytes in a specific human tumor microenvironment, and PFKFB3 might be a potential therapeutic target for not only cancer cells but also tumor-associated monocytes in human HCC.
    LAY SUMMARY: PD-L1 expressed on APCs, rather than tumor cells, has been reported to play essential roles in checkpoint blockade therapy. A fundamental understanding of mechanisms that regulate the expression of PD-L1 on tumor infiltrating monocytes/macrophages will undoubtedly lead to the possibility of developing novel PD-L1 blockade strategies with high specificity and efficiency. The current study provides evidence that cellular glycolysis mediates the activation of monocytes by tumor microenvironmental cues, which lead to the induction of PD-L1 expression on these cells and subsequent autologous CD8+ T cell suppression in peritumoral tissues of human HCC. Notably, a key glycolytic enzyme, PFKFB3, has been identified as an important mediator in regulating PD-L1 expression by inducing the activation of NF-κB signaling pathway. These data unveils a novel mechanism by which metabolic switch links immune activation response to immune tolerance in the tumor milieu, and thus indicate efficient targets for future immune-based anti-cancer therapies.
    Keywords:  NF-κB; PD-L1; PFKFB3; glycolysis; immune privilege; tumor-associated monocytes
  4. Curr Mol Med. 2019 May 08.
    Chen Y, Yan Q, Xu Y, Ye F, Sun X, Zhu H, Wang H.
      BACKGROUND: Bcl-2/adenovirus E1B-19kDa-interacting protein (BNIP3), an important target of hypoxia-inducible factors-1 alpha (HIF-1α), is reported to be over-expressed in hypoxic condition. Our previous study confirmed the protective effect by BNIP3-mediated autophagy in detached retina. The aim of the study was to evaluate the role of BNIP3-mediated autophagy in retinal pigment epithelial (RPE) cells under hypoxia. Furthermore, the relationship among BNIP3, vascular endothelial growth factor (VEGF) and inflammatory response was observed in hypoxic RPE cells. <p> Methods: BNIP3-diminished retinal pigment epithelial cells were generated by small interfering RNA (siRNA) technology in ARPE-19 cells, a human retinal pigment epithelial cell line. Both normal and BNIP3-diminished ARPE-19 cells were then subjected to hypoxic challenge using cobalt (II) chloride (CoCl2) or the normoxic condition. The relation among autophagy, VEGF and inflammatory factors (IL-18, IL-8, MMP-2, MMP-9, NLRP3, TNF-α) expression by RPE cells were examined using Polymerase Chain Reaction (PCR). Protein levels of HIF-1α, BNIP3, makers of autophagy and markers of mTORC1 pathways were analyzed using Western Blot. Locating BNIP3 in cells by using immunofluorescence. Cell viability was measured using Cell Counting kit-8. <p> Results: BNIP3, HIF-1α and markers of autophagy were upregulated in ARPE-19 under hypoxia. Importantly, hypoxia-induced autophagy via mTORC1 pathways, also it was blocked upon BNIP3 knock-down. Additionally, the suppression on cell viability was relieved after autophagy activation by suppressing mTORC1 under hypoxia. Moreover, inhibition of autophagy upregulated VEGF and IL-18 expression, while downregulated other inflammatory factors in hypoxic ARPE-19. <p> Conclusion: BNIP3-mediated autophagy induced by hypoxia may regulate inflammatory response and VEGF expression, which can affect the cell viability of RPE under hypoxia.
    Keywords:  Autophagy; BNIP3; Inflammation; RPEs; VEGF; hypoxia
  5. Nat Commun. 2019 May 09. 10(1): 2123
    Kedia-Mehta N, Finlay DK.
      Changes in cellular metabolism are associated with the activation of diverse immune subsets. These changes are fuelled by nutrients including glucose, amino acids and fatty acids, and are closely linked to immune cell fate and function. An emerging concept is that nutrients are not equally available to all immune cells, suggesting that the regulation of nutrient utility through competitive uptake and use is important for controlling immune responses. This review considers immune microenvironments where nutrients become limiting, the signalling alterations caused by insufficient nutrients, and the importance of nutrient availability in the regulation of immune responses.
  6. Cancer Cell Int. 2019 ;19 116
    Yu S, Zhou R, Yang T, Liu S, Cui Z, Qiao Q, Zhang J.
      Background: Hypoxic microenvironments play a significant role in the progression of colorectal cancer (CRC). Silencing information regulator 1 (SIRT1), a class III histone deacetylase, modulates the multiple biological behaviors of cancer. However, its role in CRC remains unclear. This study aims to explore the role of SIRT1 in CRC migration and invasion under hypoxia.Methods: SIRT1 protein and mRNA levels were detected by Western blotting and real-time PCR in CRC cells exposed to hypoxia (1% O2). The migration and invasion abilities of SW480 and HCT116 cells with SIRT1 overexpression or knockdown were studied with transwell assays, and the results were confirmed by those of treatment with specific SIRT1 activator (SRT1720) and inhibitor (EX527). The dual-luciferase reporter systems with a series of SIRT1 promoter truncations were used to analyze their transcriptional activities, respectively. After a bioinformatic analysis of potential transcription factors, the direct interaction between the transcription factor and SIRT1 promoter was determined by chromatin immunoprecipitation (ChIP) assays. Western blot and real-time PCR assays were used to detect the activation and acetylation levels of the NF-κB pathway.
    Results: The protein and mRNA levels of SIRT1 were significantly decreased under hypoxia, and these effects were replicated by cobalt chloride treatment. Hypoxia promoted cell migration and invasion, which were impeded by the overexpression or activation of SIRT1 and promoted by the knockdown or inhibition of SIRT1. The dual-luciferase reporter gene and ChIP analyses revealed that the core regulatory elements located 100 bp upstream of the SIRT1 promoter and early growth response factor 1 (EGR1) could interact with this DNA sequence. Subsequent rescue experiments suggested that EGR1 was essential for hypoxia-mediated SIRT1 transcriptional suppression. Western blot analyses demonstrated that SIRT1 overexpression eliminated the p65 acetylation induced by hypoxia along with the decreased MMP-2/-9, suggesting that NF-κB was a direct downstream target of SIRT1 and might regulate cell migration and invasion through MMP-2/-9.
    Conclusions: Our results establish for the first time that EGR1 plays an important role in regulating SIRT1 expression under hypoxia. Hypoxia promotes CRC cell migration and invasion in a SIRT1-dependent manner. And a potential SIRT1/NF-κB/MMP-2/-9 axis modulates this process.
    Keywords:  Colorectal cancer; EGR1; Hypoxia; Invasion; Migration; SIRT1
  7. J Immunol Res. 2019 ;2019 5087847
    Lee EG, Luckett-Chastain LR, Calhoun KN, Frempah B, Bastian A, Gallucci RM.
      Diabetes currently affects over twenty-five million Americans. Annual health care cost of diabetes exceeds $254 billion and is associated with a distinct set of diabetic complications that include delayed wound healing and diabetic ulcers. Interleukin 6 (IL-6) plays an important role in wound healing and is known to be elevated in the serum of both type I and type II diabetes patients. This study assesses the expression and function of IL-6 in the hyperglycemic epidermis and keratinocyte culture. Streptozotocin-treated mice were wounded six weeks after induction of hyperglycemia. Wound closure, protein, and mRNA expression were assessed up to 13 days of postwounding. Wound closure was delayed 4-5 days in hyperglycemic animals. Hyperglycemic wounds displayed greater IL-6 and IL-6Rα protein expression at 1, 7, and 10 days of postwounding compared to euglycemic control. However, IL-6Rα mRNA expression was reduced at all time points beyond day 1, while IL-6 mRNA expression did not significantly differ at any time point. SOCS3 mRNA expression was higher in the hyperglycemic skin at every time point. Imaging of fluorescent immunohistology also revealed significantly lower expression of SOCS3, but higher nuclear pSTAT3 in the epidermis of the hyperglycemic skin. Primary mouse keratinocytes cultured in high glucose for 7 days displayed 2-fold higher IL-6Rα mRNA and higher rmIL-6-induced nuclear pSTAT3, but lower SOCS3 basal levels compared to normal glucose-cultured cells. Thus, it appears that delayed diabetic skin wound healing is associated with increased induction and expression of IL-6 and its receptor, but its function in epidermal keratinocytes may be impaired.
  8. BMC Bioinformatics. 2019 May 01. 20(Suppl 7): 195
    Hao Y, Li D, Xu Y, Ouyang J, Wang Y, Zhang Y, Li B, Xie L, Qin G.
      BACKGROUND: Lipid metabolism reprogramming is a hallmark for tumor which contributes to tumorigenesis and progression, but the commonality and difference of lipid metabolism among pan-cancer is not fully investigated. Increasing evidences suggest that the alterations in tumor metabolism, including metabolite abundance and accumulation of metabolic products, lead to local immunosuppression in the tumor microenvironment. An integrated analysis of lipid metabolism in cancers from different tissues using multiple omics data may provide novel insight into the understanding of tumorigenesis and progression.RESULTS: Through systematic analysis of the multiple omics data from TCGA, we found that the most-widely altered lipid metabolism pathways in pan-cancer are fatty acid metabolism, arachidonic acid metabolism, cholesterol metabolism and PPAR signaling. Gene expression profiles of fatty acid metabolism show commonalities across pan-cancer, while the alteration in cholesterol metabolism and arachidonic acid metabolism differ with tissue origin, suggesting tissue specific lipid metabolism features in different tumor types. An integrated analysis of gene expression, DNA methylation and mutations revealed factors that regulate gene expression, including the differentially methylated sites and mutations of the lipid genes, as well as mutation and differential expression of the up-stream transcription factors for the lipid metabolism pathways. Correlation analysis of the proportion of immune cells in the tumor microenvironment and the expression of lipid metabolism genes revealed immune-related differentially expressed lipid metabolic genes, indicating the potential crosstalk between lipid metabolism and immune response. Genes related to lipid metabolism and immune response that are associated with poor prognosis were discovered including HMGCS2, GPX2 and CD36, which may provide clues for tumor biomarkers or therapeutic targets.
    CONCLUSIONS: Our study provides an integrated analysis of lipid metabolism in pan-cancer, highlights the perturbation of key metabolism processes in tumorigenesis and clarificates the regulation mechanism of abnormal lipid metabolism and effects of lipid metabolism on tumor immune microenvironment. This study also provides new clues for biomarkers or therapeutic targets of lipid metabolism in tumors.
    Keywords:  Lipid metabolism; Multiple omics analysis; Pan-cancer; Tumor immune micro-environment