bims-stacyt Biomed News
on Paracrine crosstalk between cancer and the organism
Issue of 2021‒08‒29
four papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. Cancers (Basel). 2021 Aug 19. pii: 4176. [Epub ahead of print]13(16):
      Tissue hypoxia is commonly observed in head and neck squamous cell carcinomas (HNSCCs), resulting in molecular and functional alterations of the tumor cells. The aim of this study was to characterize tumor-derived small extracellular vesicles (sEVs) released under hypoxic vs. normoxic conditions and analyze their proteomic content. HNSCC cells (FaDu, PCI-30, SCC-25) and HaCaT keratinocytes were cultured in 21, 10, 5, and 1% O2. sEVs were isolated from supernatants using size exclusion chromatography (SEC) and characterized by nanoparticle tracking analysis, electron microscopy, immunoblotting, and high-resolution mass spectrometry. Isolated sEVs ranged in size from 125-135 nm and contained CD63 and CD9 but not Grp94. sEVs reflected the hypoxic profile of HNSCC parent cells: about 15% of the total detected proteins were unique for hypoxic cells. Hypoxic sEVs expressed a common signature of seven hypoxia-related proteins (KT33B, DYSF, STON2, MLX, LIPA3, NEK5, P12L1) and were enriched in pro-angiogenic proteins. Protein profiles of sEVs reflected the degree of tumor hypoxia and could serve as potential sEV-based biomarkers for hypoxic conditions. Adaptation of HNSCC cells to hypoxia is associated with increased release of sEVs, which are enriched in a unique protein profile. Thus, tumor-derived sEVs can potentially be useful for evaluating levels of hypoxia in HNSCC.
    Keywords:  HNSCC; exosomes; hypoxia; proteomics; small extracellular vesicles
  2. Cell Death Differ. 2021 Aug 27.
      Mounting evidence indicates that immunogenic therapies engaging the unfolded protein response (UPR) following endoplasmic reticulum (ER) stress favor proficient cancer cell-immune interactions, by stimulating the release of immunomodulatory/proinflammatory factors by stressed or dying cancer cells. UPR-driven transcription of proinflammatory cytokines/chemokines exert beneficial or detrimental effects on tumor growth and antitumor immunity, but the cell-autonomous machinery governing the cancer cell inflammatory output in response to immunogenic therapies remains poorly defined. Here, we profiled the transcriptome of cancer cells responding to immunogenic or weakly immunogenic treatments. Bioinformatics-driven pathway analysis indicated that immunogenic treatments instigated a NF-κB/AP-1-inflammatory stress response, which dissociated from both cell death and UPR. This stress-induced inflammation was specifically abolished by the IRE1α-kinase inhibitor KIRA6. Supernatants from immunogenic chemotherapy and KIRA6 co-treated cancer cells were deprived of proinflammatory/chemoattractant factors and failed to mobilize neutrophils and induce dendritic cell maturation. Furthermore, KIRA6 significantly reduced the in vivo vaccination potential of dying cancer cells responding to immunogenic chemotherapy. Mechanistically, we found that the anti-inflammatory effect of KIRA6 was still effective in IRE1α-deficient cells, indicating a hitherto unknown off-target effector of this IRE1α-kinase inhibitor. Generation of a KIRA6-clickable photoaffinity probe, mass spectrometry, and co-immunoprecipitation analysis identified cytosolic HSP60 as a KIRA6 off-target in the IKK-driven NF-κB pathway. In sum, our study unravels that HSP60 is a KIRA6-inhibitable upstream regulator of the NF-κB/AP-1-inflammatory stress responses evoked by immunogenic treatments. It also urges caution when interpreting the anti-inflammatory action of IRE1α chemical inhibitors.
  3. Transl Pediatr. 2021 Jul;10(7): 1792-1804
      Background: Leukemia stem cells (LSCs) play pivotal roles in leukemogenesis, and are closely implicated in leukemia relapse and chemoresistance. LSCs are tightly modulated by hypoxic exposure and macrophage-conditioned microenvironment. Nevertheless, the impacts on the biology of LSCs imposed by the interaction of hypoxia and macrophage polarization remain elusive.Methods: In the study, LSCs characterized by CD34+CD38- immunophenotype sorted from KG1α and primary AML cells were employed as in vitro and ex vivo cell models. mRNA and protein expressions of cytokine/chemokine of cells under normoxic and hypoxic conditions were determined by RT-PCR and western blot. Macrophage polarization, cell cycle and apoptosis were determined by flowcytometry. Cell viability was assayed by CCK-8.
    Results: Macrophages preferentially presented with M2 polarization phenotype characterized by upregulated VEGF and CCL17 cytokine/chemokine profile, when stimulated by specific set of cytokines under hypoxic exposure, and induced an anti-inflammatory microenvironment. LSCs exhibited significantly increased cell viability, colony-forming capacity and chemoresistance when co-incubated in hypoxic conditioned medium (H-CM) primed by polarized M1 macrophages. VEGF expression was upregulated in LSCs which in turn activated survivin expression. VEGF-mediated upregulation of survivin could be abolished by inhibition of VEGF receptor, but not blocked by survivin-targeting siRNA. In addition, survivin upregulation exerted antiapoptotic effects and was associated with increased chemoresistance. Finally, VEGF mediated transcriptional induction of HIF-1α of LSCs coincubated in H-CM, and HIF-1α induction in turn enhanced chemoresistance and reduced cell apoptosis.
    Conclusions: To our best knowledge, this is the first study that focus to explore molecule players and interacting signal pathways regulating LSC biology under hypoxic exposure. It reveals that hypoxia preferentially skew macrophage M2 polarization with specific cytokine profile and proinflammatory microenvironment, which impacts malignant behavior of LSCs. VEGF-HIF-1α interaction is closely implicated in sustaining LSCs survival under hypoxic exposure and might be of potential target of novel therapy.
    Keywords:  Acute myeloid leukemia (AML); chemoresistance; hypoxia-inducible factor 1α (HIF-1α); leukemia stem cells (LSCs); vascular endothelial growth factor (VEGF)
  4. Cells. 2021 Aug 19. pii: 2130. [Epub ahead of print]10(8):
      Adenine nucleotide translocase 1 (ANT1) transfers ATP and ADP over the mitochondrial inner membrane and thus supplies the cell with energy. This study analyzed the role of ANT1 in the immune response of ischemic heart tissue. Ischemic ANT1 overexpressing hearts experienced a shift toward an anti-inflammatory immune response. The shift was characterized by low interleukin (IL)-1β expression and M1 macrophage infiltration, whereas M2 macrophage infiltration and levels of IL-10, IL-4, and transforming growth factor (TGFβ) were increased. The modulated immune response correlated with high mitochondrial integrity, reduced oxidative stress, low left ventricular end-diastolic heart pressure, and a high survival rate. Isolated ANT1-transgenic (ANT1-TG) cardiomyocytes expressed low levels of pro-inflammatory cytokines such as IL-1α, tumor necrosis factor α, and TGFβ. However, they showed increased expression and cellular release of anti-inflammatory immunomodulators such as vascular endothelial growth factor. The secretome from ANT1-TG cardiomyocytes initiated stress resistance when applied to ischemic wild-type cardiomyocytes and endothelial cells. It additionally prevented macrophages from expressing pro-inflammatory cytokines. Additionally, ANT1 expression correlated with genes that are related to cytokine and growth factor pathways in hearts of patients with ischemic cardiomyopathy. In conclusion, ANT1-TG cardiomyocytes secrete soluble factors that influence ischemic cardiac cells and initiate an anti-inflammatory immune response in ischemic hearts.
    Keywords:  adenine nucleotide translocase; cytokine; immune response; ischemic cardiomyopathy; macrophages; mitochondria; myocardial infarction