Publications by authors named "Patrizia Agostinis"

175 Publications

BNIP3 in melanoma: isn't it IRONic?

Mol Cell Oncol 2021 2;8(4):1947169. Epub 2021 Aug 2.

Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.

Melanoma cells exploit mitophagy and hypoxia signaling to promote their growth. In a recent study, we found that loss of B-cell lymphoma 2 (BCL-2)/adenovirus E1B 19kDa protein-interacting protein 3 (BNIP3) curbed Hypoxia Inducible Factor 1 alpha (HIF-1α) levels and melanoma growth . Insufficient levels of BNIP3 boost iron-driven prolyl hydroxylase 2 (Phd2)-mediated degradation of HIF-1α by exacerbating nuclear receptor activator 4 (Ncoa4)-mediated ferritinophagy. Thus, BNIP3 promotes melanoma growth by controlling iron metabolism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/23723556.2021.1947169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8489953PMC
August 2021

Stress-induced inflammation evoked by immunogenic cell death is blunted by the IRE1α kinase inhibitor KIRA6 through HSP60 targeting.

Cell Death Differ 2021 Aug 27. Epub 2021 Aug 27.

Cell Death Research and Therapy Laboratory, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41418-021-00853-5DOI Listing
August 2021

The lysosome as a master regulator of iron metabolism.

Trends Biochem Sci 2021 Aug 9. Epub 2021 Aug 9.

Laboratory of Cell Death and Research, Vlaams Instituut voor Biotechnologie (VIB)-Katholieke Universiteit (KU) Leuven Center for Cancer Biology, Leuven, Belgium; Laboratory of Cell Death and Research, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium. Electronic address:

Intracellular iron fulfills crucial cellular processes, including DNA synthesis and mitochondrial metabolism, but also mediates ferroptosis, a regulated form of cell death driven by lipid-based reactive oxygen species (ROS). Beyond their established role in degradation and recycling, lysosomes occupy a central position in iron homeostasis and integrate metabolic and cell death signals emanating from different subcellular sites. We discuss the central role of the lysosome in preserving iron homeostasis and provide an integrated outlook of the regulatory circuits coupling the lysosomal system to the control of iron trafficking, interorganellar crosstalk, and ferroptosis induction. We also discuss novel studies unraveling how deregulated lysosomal iron-handling functions contribute to cancer, neurodegeneration, and viral infection, and can be harnessed for therapeutic interventions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tibs.2021.07.003DOI Listing
August 2021

BNIP3 promotes HIF-1α-driven melanoma growth by curbing intracellular iron homeostasis.

EMBO J 2021 May 1;40(10):e106214. Epub 2021 May 1.

Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.

BNIP3 is a mitophagy receptor with context-dependent roles in cancer, but whether and how it modulates melanoma growth in vivo remains unknown. Here, we found that elevated BNIP3 levels correlated with poorer melanoma patient's survival and depletion of BNIP3 in B16-F10 melanoma cells compromised tumor growth in vivo. BNIP3 depletion halted mitophagy and enforced a PHD2-mediated downregulation of HIF-1α and its glycolytic program both in vitro and in vivo. Mechanistically, we found that BNIP3-deprived melanoma cells displayed increased intracellular iron levels caused by heightened NCOA4-mediated ferritinophagy, which fostered PHD2-mediated HIF-1α destabilization. These effects were not phenocopied by ATG5 or NIX silencing. Restoring HIF-1α levels in BNIP3-depleted melanoma cells rescued their metabolic phenotype and tumor growth in vivo, but did not affect NCOA4 turnover, underscoring that these BNIP3 effects are not secondary to HIF-1α. These results unravel an unexpected role of BNIP3 as upstream regulator of the pro-tumorigenic HIF-1α glycolytic program in melanoma cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.15252/embj.2020106214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8126921PMC
May 2021

Endothelial cell autophagy in homeostasis and cancer.

FEBS Lett 2021 06 24;595(11):1497-1511. Epub 2021 Apr 24.

Cell Death Research and Therapy Group, Department of Cellular and Molecular Medicine, KU Leuven, Belgium.

Autophagy, the major lysosomal pathway for the degradation and recycling of cytoplasmic materials, is increasingly recognized as a major player in endothelial cell (EC) biology and vascular pathology. Particularly in solid tumors, tumor microenvironmental stress such as hypoxia, nutrient deprivation, inflammatory mediators, and metabolic aberrations stimulates autophagy in tumor-associated blood vessels. Increased autophagy in ECs may serve as a mechanism to alleviate stress and restrict exacerbated inflammatory responses. However, increased autophagy in tumor-associated ECs can re-model metabolic pathways and affect the trafficking and surface availability of key mediators and regulators of the interplay between EC and immune cells. In line with this, heightened EC autophagy is involved in pathological angiogenesis, inflammatory, and immune responses. Here, we review major cellular and molecular mechanisms regulated by autophagy in ECs under physiological conditions and discuss recent evidence implicating EC autophagy in tumor angiogenesis and immunosurveillance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/1873-3468.14087DOI Listing
June 2021

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition).

Autophagy 2021 Jan 8;17(1):1-382. Epub 2021 Feb 8.

University of Crete, School of Medicine, Laboratory of Clinical Microbiology and Microbial Pathogenesis, Voutes, Heraklion, Crete, Greece; Foundation for Research and Technology, Institute of Molecular Biology and Biotechnology (IMBB), Heraklion, Crete, Greece.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/15548627.2020.1797280DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996087PMC
January 2021

Downregulation of miR-17-92 Cluster by PERK Fine-Tunes Unfolded Protein Response Mediated Apoptosis.

Life (Basel) 2021 Jan 6;11(1). Epub 2021 Jan 6.

Discipline of Pathology, Cancer Progression and Treatment Research Group, Lambe Institute for Translational Research, School of Medicine, National University of Ireland-Galway, H91 TK33 Galway, Ireland.

An important event in the unfolded protein response (UPR) is activation of the endoplasmic reticulum (ER) kinase PERK. The PERK signalling branch initially mediates a prosurvival response, which progresses to a proapoptotic response upon prolonged ER stress. However, the molecular mechanisms of PERK-mediated cell death are not well understood. Here we show that expression of the primary miR-17-92 transcript and mature miRNAs belonging to the miR-17-92 cluster are decreased during UPR. We found that miR-17-92 promoter reporter activity was reduced during UPR in a PERK-dependent manner. Furthermore, we show that activity of the miR-17-92 promoter is repressed by ectopic expression of ATF4 and NRF2. Promoter deletion analysis mapped the region responding to UPR-mediated repression to a site in the proximal region of the miR-17-92 promoter. Hypericin-mediated photo-oxidative ER damage reduced the expression of miRNAs belonging to the miR-17-92 cluster in wild-type but not in PERK-deficient cells. Importantly, ER stress-induced apoptosis was inhibited upon miR-17-92 overexpression in SH-SY5Y and H9c2 cells. Our results reveal a novel function for ATF4 and NRF2, where repression of the miR-17-92 cluster plays an important role in ER stress-mediated apoptosis. Mechanistic details are provided for the potentiation of cell death via sustained PERK signalling mediated repression of the miR-17-92 cluster.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/life11010030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825066PMC
January 2021

ATP13A3 is a major component of the enigmatic mammalian polyamine transport system.

J Biol Chem 2021 Jan-Jun;296:100182. Epub 2020 Dec 17.

Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium. Electronic address:

Polyamines, such as putrescine, spermidine, and spermine, are physiologically important polycations, but the transporters responsible for their uptake in mammalian cells remain poorly characterized. Here, we reveal a new component of the mammalian polyamine transport system using CHO-MG cells, a widely used model to study alternative polyamine uptake routes and characterize polyamine transport inhibitors for therapy. CHO-MG cells present polyamine uptake deficiency and resistance to a toxic polyamine biosynthesis inhibitor methylglyoxal bis-(guanylhydrazone) (MGBG), but the molecular defects responsible for these cellular characteristics remain unknown. By genome sequencing of CHO-MG cells, we identified mutations in an unexplored gene, ATP13A3, and found disturbed mRNA and protein expression. ATP13A3 encodes for an orphan P5B-ATPase (ATP13A3), a P-type transport ATPase that represents a candidate polyamine transporter. Interestingly, ATP13A3 complemented the putrescine transport deficiency and MGBG resistance of CHO-MG cells, whereas its knockdown in WT cells induced a CHO-MG phenotype demonstrated as a decrease in putrescine uptake and MGBG sensitivity. Taken together, our findings identify ATP13A3, which has been previously genetically linked with pulmonary arterial hypertension, as a major component of the mammalian polyamine transport system that confers sensitivity to MGBG.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA120.013908DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7948421PMC
August 2021

Kinase Photoaffinity Labeling Reveals Low Selectivity Profile of the IRE1 Targeting Imidazopyrazine-Based KIRA6 Inhibitor.

ACS Chem Biol 2020 12 8;15(12):3106-3111. Epub 2020 Dec 8.

KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Chemical Biology, Herestraat 49 Box 802, 3000 Leuven, Belgium.

Inositol-requiring enzyme 1α (IRE1α) is one of three endoplasmic reticulum stress sensors. Upon activation of its kinase domain, IRE1α splices the mRNA substrate XBP1, which activates the unfolded protein response. IRE1α has emerged as a therapeutic target as its hyperactivation is implicated in various diseases. Kinase inhibiting RNase attenuator 6 (KIRA6) is an allosteric IRE1α inhibitor targeting the ATP binding pocket, resulting in effective blockage of the IRE1α-XBP1 pathway in mouse models of diabetes and pain. However, recent studies indicate that KIRA6 is not as selective as initially thought. Here, we developed a photoaffinity-based KIRA6 probe to reveal its selectivity. Surprisingly, the majority of off-targets that we identified were not protein kinases but mostly nucleotide-binding proteins. Furthermore, we found that the promiscuous off-target profile of KIRA6 is not cell-line-dependent. Overall, this study calls for caution when KIRA6 is used in IRE1α-targeted studies and illustrates the power of kinase photoaffinity probes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acschembio.0c00802DOI Listing
December 2020

ATP13A2-mediated endo-lysosomal polyamine export counters mitochondrial oxidative stress.

Proc Natl Acad Sci U S A 2020 12 23;117(49):31198-31207. Epub 2020 Nov 23.

Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), 3000 Leuven, Belgium;

Recessive loss-of-function mutations in () are associated with a spectrum of neurodegenerative disorders, including Parkinson's disease (PD). We recently revealed that the late endo-lysosomal transporter ATP13A2 pumps polyamines like spermine into the cytosol, whereas ATP13A2 dysfunction causes lysosomal polyamine accumulation and rupture. Here, we investigate how ATP13A2 provides protection against mitochondrial toxins such as rotenone, an environmental PD risk factor. Rotenone promoted mitochondrial-generated superoxide (MitoROS), which was exacerbated by ATP13A2 deficiency in SH-SY5Y cells and patient-derived fibroblasts, disturbing mitochondrial functionality and inducing toxicity and cell death. Moreover, ATP13A2 knockdown induced an ATF4-CHOP-dependent stress response following rotenone exposure. MitoROS and ATF4-CHOP were blocked by MitoTEMPO, a mitochondrial antioxidant, suggesting that the impact of ATP13A2 on MitoROS may relate to the antioxidant properties of spermine. Pharmacological inhibition of intracellular polyamine synthesis with α-difluoromethylornithine (DFMO) also increased MitoROS and ATF4 when ATP13A2 was deficient. The polyamine transport activity of ATP13A2 was required for lowering rotenone/DFMO-induced MitoROS, whereas exogenous spermine quenched rotenone-induced MitoROS via ATP13A2. Interestingly, fluorescently labeled spermine uptake in the mitochondria dropped as a consequence of ATP13A2 transport deficiency. Our cellular observations were recapitulated in vivo, in a strain deficient in the ATP13A2 ortholog These animals exhibited a basal elevated MitoROS level, mitochondrial dysfunction, and enhanced stress response regulated by , the ortholog of ATF4, causing hypersensitivity to rotenone, which was reversible with MitoTEMPO. Together, our study reveals a conserved cell protective pathway that counters mitochondrial oxidative stress via ATP13A2-mediated lysosomal spermine export.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1922342117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7733819PMC
December 2020

Correction: Smac mimetic suppresses tunicamycin-induced apoptosis via resolution of ER stress.

Cell Death Dis 2020 Sep 25;11(9):806. Epub 2020 Sep 25.

Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Komturstrasse 3a, 60528, Frankfurt, Germany.

Since online publication of this article, the authors noticed that Fig. 3b does not show the correct graph for Bortezomib. The corrected graph for Fig. 3b is provided below. This unintentional mistake does not alter the conclusions of the study. The authors apologise for any inconvenience caused.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-020-02991-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7519679PMC
September 2020

Is hydroxychloroquine beneficial for COVID-19 patients?

Cell Death Dis 2020 07 8;11(7):512. Epub 2020 Jul 8.

Department of Rheumatology and Immunology, The Third Affiliated Hospital of Southern Medical University, No. 183, Zhongshan Avenue West, Tianhe District, Guangzhou, 510630, Guangdong, China.

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in December 2019. As similar cases rapidly emerged around the world, the World Health Organization (WHO) declared a public health emergency of international concern on January 30, 2020 and pronounced the rapidly spreading coronavirus outbreak as a pandemic on March 11, 2020. The virus has reached almost all countries of the globe. As of June 3, 2020, the accumulated confirmed cases reached 6,479,405 with more than 383,013 deaths worldwide. The urgent and emergency care of COVID-19 patients calls for effective drugs, in addition to the beneficial effects of remdesivir, to control the disease and halt the pandemic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-020-2721-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7341710PMC
July 2020

Consensus guidelines for the definition, detection and interpretation of immunogenic cell death.

J Immunother Cancer 2020 03;8(1)

Program of Immunology and Immunotherapy, Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain.

Cells succumbing to stress via regulated cell death (RCD) can initiate an adaptive immune response associated with immunological memory, provided they display sufficient antigenicity and adjuvanticity. Moreover, multiple intracellular and microenvironmental features determine the propensity of RCD to drive adaptive immunity. Here, we provide an updated operational definition of immunogenic cell death (ICD), discuss the key factors that dictate the ability of dying cells to drive an adaptive immune response, summarize experimental assays that are currently available for the assessment of ICD in vitro and in vivo, and formulate guidelines for their interpretation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jitc-2019-000337DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064135PMC
March 2020

Decoding cancer cell death-driven immune cell recruitment: An in vivo method for site-of-vaccination analyses.

Methods Enzymol 2020 2;636:185-207. Epub 2019 May 2.

Department for Cellular and Molecular Medicine, Cell Death Research & Therapy (CDRT) Unit, KU Leuven, Leuven, Belgium. Electronic address:

Anticancer vaccines have recently received renewed attention for immunotherapy of at least a subset of cancer-types. Such vaccines mostly involve either killed cancer or tumor cells alone, or combinations thereof with specific (co-incubated) innate immune cells. In recent years, the immunogenic characteristics of the dead or dying cancer cells have emerged as decisive factors behind the success of anticancer vaccines. This has amplified the importance of accounting for immunology of cell death while preparing anticancer vaccines. This, in turn, has increased the emphasis on the immune reactions at the site-of-vaccination since the therapeutic efficacy of the killed cancer/tumor cell vaccines is contingent upon the nature and characteristics of these reactions at the site-of-injection. In this article, we present a systematic methodology that exploits the murine ear pinna model to study differential immune cell recruitment by dead/dying cancer cells injected in vivo, thereby modeling the site-of-injection relevant for anticancer vaccines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.mie.2019.04.013DOI Listing
June 2021

Lipid availability determines fate of skeletal progenitor cells via SOX9.

Nature 2020 03 26;579(7797):111-117. Epub 2020 Feb 26.

Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium.

The avascular nature of cartilage makes it a unique tissue, but whether and how the absence of nutrient supply regulates chondrogenesis remain unknown. Here we show that obstruction of vascular invasion during bone healing favours chondrogenic over osteogenic differentiation of skeletal progenitor cells. Unexpectedly, this process is driven by a decreased availability of extracellular lipids. When lipids are scarce, skeletal progenitors activate forkhead box O (FOXO) transcription factors, which bind to the Sox9 promoter and increase its expression. Besides initiating chondrogenesis, SOX9 acts as a regulator of cellular metabolism by suppressing oxidation of fatty acids, and thus adapts the cells to an avascular life. Our results define lipid scarcity as an important determinant of chondrogenic commitment, reveal a role for FOXO transcription factors during lipid starvation, and identify SOX9 as a critical metabolic mediator. These data highlight the importance of the nutritional microenvironment in the specification of skeletal cell fate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41586-020-2050-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060079PMC
March 2020

ATP13A2 deficiency disrupts lysosomal polyamine export.

Nature 2020 02 29;578(7795):419-424. Epub 2020 Jan 29.

Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.

ATP13A2 (PARK9) is a late endolysosomal transporter that is genetically implicated in a spectrum of neurodegenerative disorders, including Kufor-Rakeb syndrome-a parkinsonism with dementia-and early-onset Parkinson's disease. ATP13A2 offers protection against genetic and environmental risk factors of Parkinson's disease, whereas loss of ATP13A2 compromises lysosomes. However, the transport function of ATP13A2 in lysosomes remains unclear. Here we establish ATP13A2 as a lysosomal polyamine exporter that shows the highest affinity for spermine among the polyamines examined. Polyamines stimulate the activity of purified ATP13A2, whereas ATP13A2 mutants that are implicated in disease are functionally impaired to a degree that correlates with the disease phenotype. ATP13A2 promotes the cellular uptake of polyamines by endocytosis and transports them into the cytosol, highlighting a role for endolysosomes in the uptake of polyamines into cells. At high concentrations polyamines induce cell toxicity, which is exacerbated by ATP13A2 loss due to lysosomal dysfunction, lysosomal rupture and cathepsin B activation. This phenotype is recapitulated in neurons and nematodes with impaired expression of ATP13A2 or its orthologues. We present defective lysosomal polyamine export as a mechanism for lysosome-dependent cell death that may be implicated in neurodegeneration, and shed light on the molecular identity of the mammalian polyamine transport system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41586-020-1968-7DOI Listing
February 2020

Type I interferons and dendritic cells in cancer immunotherapy.

Int Rev Cell Mol Biol 2019 20;348:217-262. Epub 2019 Jun 20.

Cell Death Research & Therapy (CDRT) Unit, Department for Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium. Electronic address:

Type I interferons (IFNs) facilitate cancer immunosurveillance, antitumor immunity and antitumor efficacy of conventional cell death-inducing therapies (chemotherapy/radiotherapy) as well as immunotherapy. Moreover, it is clear that dendritic cells (DCs) play a significant role in aiding type I IFN-driven immunity. Owing to these antitumor properties several immunotherapies involving, or inducing, type I IFNs have received considerable clinical attention, e.g., recombinant IFNα2 or agonists targeting pattern recognition receptor (PRR) pathways like Toll-like receptors (TLRs), cGAS-STING or RIG-I/MDA5/MAVS. A series of preclinical and clinical evidence concurs that the success of anticancer therapy hinges on responsiveness of both cancer cells and DCs to type I IFNs. In this article, we discuss this link between type I IFNs and DCs in the context of cancer biology, with particular attention to mechanisms behind type I IFN production, their impact on DC driven anticancer immunity, and the implications of this for cancer immunotherapy, including DC-based vaccines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.ircmb.2019.06.001DOI Listing
April 2020

Trial watch: dendritic cell vaccination for cancer immunotherapy.

Oncoimmunology 2019;8(11):e1638212. Epub 2019 Jul 18.

Cell Death Research & Therapy (CDRT) unit, Department of Cellular & Molecular Medicine, KU Leuven, Leuven, Belgium.

Dendritic- cells (DCs) have received considerable attention as potential targets for the development of anticancer vaccines. DC-based anticancer vaccination relies on patient-derived DCs pulsed with a source of tumor-associated antigens (TAAs) in the context of standardized maturation-cocktails, followed by their reinfusion. Extensive evidence has confirmed that DC-based vaccines can generate TAA-specific, cytotoxic T cells. Nonetheless, clinical efficacy of DC-based vaccines remains suboptimal, reflecting the widespread immunosuppression within tumors. Thus, clinical interest is being refocused on DC-based vaccines as combinatorial partners for T cell-targeting immunotherapies. Here, we summarize the most recent preclinical/clinical development of anticancer DC vaccination and discuss future perspectives for DC-based vaccines in immuno-oncology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/2162402X.2019.1638212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6791419PMC
July 2019

Mitophagy in Cancer: A Tale of Adaptation.

Cells 2019 05 22;8(5). Epub 2019 May 22.

Laboratory of Cell Death Research and Therapy, Department for Cellular and Molecular Medicine, Campus Gasthuisberg, University of Leuven (KU Leuven), Herestraat 49, B-3000 Leuven, Belgium.

:In the past years, we have learnt that tumors co-evolve with their microenvironment, and that the active interaction between cancer cells and stromal cells plays a pivotal role in cancer initiation, progression and treatment response. Among the players involved, the pathways regulating mitochondrial functions have been shown to be crucial for both cancer and stromal cells. This is perhaps not surprising, considering that mitochondria in both cancerous and non-cancerous cells are decisive for vital metabolic and bioenergetic functions and to elicit cell death. The central part played by mitochondria also implies the existence of stringent mitochondrial quality control mechanisms, where a specialized autophagy pathway (mitophagy) ensures the selective removal of damaged or dysfunctional mitochondria. Although the molecular underpinnings of mitophagy regulation in mammalian cells remain incomplete, it is becoming clear that mitophagy pathways are intricately linked to the metabolic rewiring of cancer cells to support the high bioenergetic demand of the tumor. In this review, after a brief introduction of the main mitophagy regulators operating in mammalian cells, we discuss emerging cell autonomous roles of mitochondria quality control in cancer onset and progression. We also discuss the relevance of mitophagy in the cellular crosstalk with the tumor microenvironment and in anti-cancer therapy responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells8050493DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6562743PMC
May 2019

Non-canonical function of IRE1α determines mitochondria-associated endoplasmic reticulum composition to control calcium transfer and bioenergetics.

Nat Cell Biol 2019 06 20;21(6):755-767. Epub 2019 May 20.

Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.

Mitochondria-associated membranes (MAMs) are central microdomains that fine-tune bioenergetics by the local transfer of calcium from the endoplasmic reticulum to the mitochondrial matrix. Here, we report an unexpected function of the endoplasmic reticulum stress transducer IRE1α as a structural determinant of MAMs that controls mitochondrial calcium uptake. IRE1α deficiency resulted in marked alterations in mitochondrial physiology and energy metabolism under resting conditions. IRE1α determined the distribution of inositol-1,4,5-trisphosphate receptors at MAMs by operating as a scaffold. Using mutagenesis analysis, we separated the housekeeping activity of IRE1α at MAMs from its canonical role in the unfolded protein response. These observations were validated in vivo in the liver of IRE1α conditional knockout mice, revealing broad implications for cellular metabolism. Our results support an alternative function of IRE1α in orchestrating the communication between the endoplasmic reticulum and mitochondria to sustain bioenergetics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41556-019-0329-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7246037PMC
June 2019

Lysosomal Pathways and Autophagy Distinctively Control Endothelial Cell Behavior to Affect Tumor Vasculature.

Front Oncol 2019 20;9:171. Epub 2019 Mar 20.

Cell Death Research and Therapy Laboratory, Department for Cellular and Molecular Medicine, KU Leuven University of Leuven, Leuven, Belgium.

Cancer cell-stromal cell crosstalk is orchestrated by a plethora of ligand-receptor interactions generating a tumor microenvironment (TME) which favors tumor growth. The high pro-angiogenic nature of the TME perpetuates the chaotic network of structurally immature, low pericyte-covered vessels characteristic of the tumor vasculature. We previously demonstrated that chloroquine (CQ) -a lysosomotropic agent used as first-generation autophagy blocker in clinical trials- induced tumor vessel normalization and reduced tumor hypoxia. CQ improved both vessel structure and maturation, whereas the conditional knockout of the crucial autophagy gene in endothelial cells (ECs) did not, thus highlighting a potential differential role for EC-associated autophagy and the lysosomes in pathological tumor angiogenesis. However, how CQ or ATG5-deficiency in ECs affect angiogenic signals regulating EC-pericyte interface and therefore vessel maturation, remains unknown. Here, we show that in ECs CQ constrained VEGF-A-mediated VEGF receptor (VEGFR)2 phosphorylation, a driver of angiogenic signaling. In the presence of CQ we observed increased expression of the decoy receptor VEGFR1 and of a lower molecular weight form of VEGFR2, suggesting receptor cleavage. Consequently, VEGF-A-driven EC spheroid sprouting was reduced by CQ treatment. Furthermore, CQ significantly affected the transcription and secretion of platelet-derived growth factor (PDGF)-AB/BB (upregulated) and Endothelin-1 (EDN1, downregulated), both modulators of perivascular cell (PC) behavior. In contrast, silencing of ATG5 in ECs had no effect on to ratio nor on and expression. Accordingly, mice harboring B16F10 melanoma tumors treated with CQ, displayed both an increased number of αSMA PCs covering tumor vessels and co-expressed PDGF receptor-β, enabling PDGF ligand dependent recruitment. Moreover, upon CQ treatment the tumoral expression of angiopoietin-1 (, which retains mural cells, and induces vessel stabilization by binding to the EC-localized cognate receptor (TIE2), was increased thus supporting the vessel normalization function of CQ. These features associated with improved tumor vasculature were not phenocopied by the specific deletion of in ECs. In conclusion, this study further unravels endothelial cell autonomous and non-autonomous mechanisms by which CQ "normalizes" the intercellular communication in the tumor vasculature independent of autophagy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2019.00171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6435524PMC
March 2019

Smac mimetic suppresses tunicamycin-induced apoptosis via resolution of ER stress.

Cell Death Dis 2019 02 15;10(3):155. Epub 2019 Feb 15.

Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Komturstrasse 3a, 60528, Frankfurt, Germany.

Since Inhibitor of Apoptosis (IAP) proteins have been implicated in cellular adaptation to endoplasmic reticulum (ER) stress, we investigated the regulation of ER stress-induced apoptosis by small-molecule second mitochondria-derived activator of caspase (Smac) mimetics that antagonize IAP proteins. Here, we discover that Smac mimetic suppresses tunicamycin (TM)-induced apoptosis via resolution of the unfolded protein response (UPR) and ER stress. Smac mimetics such as BV6 selectively inhibit apoptosis triggered by pharmacological or genetic inhibition of protein N-glycosylation using TM or knockdown of DPAGT1, the enzyme that catalyzes the first step of protein N-glycosylation. In contrast, BV6 does not rescue cell death induced by other typical ER stressors (i.e., thapsigargin (TG), dithiothreitol, brefeldin A, bortezomib, or 2-deoxyglucose). The protection from TM-triggered apoptosis is found for structurally different Smac mimetics and for genetic knockdown of cellular IAP (cIAP) proteins in several cancer types, underlining the broader relevance. Interestingly, lectin microarray profiling reveals that BV6 counteracts TM-imposed inhibition of protein glycosylation. BV6 consistently abolishes TM-stimulated accumulation of ER stress markers such as glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) and reduces protein kinase RNA-like ER kinase (PERK) phosphorylation and X box-binding protein 1 (XBP1) splicing upon TM treatment. BV6-stimulated activation of nuclear factor-κB (NF-κB) contributes to the resolution of ER stress, since NF-κB inhibition by overexpression of dominant-negative IκBα superrepressor counteracts the suppression of TM-stimulated transcriptional activation of CHOP and GRP78 by BV6. Thus, our study is the first to show that Smac mimetic protects from TM-triggered apoptosis by resolving the UPR and ER stress. This provides new insights into the regulation of cellular stress responses by Smac mimetics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-019-1381-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377606PMC
February 2019

Staying in touch: Taking a closer look at ER-Golgi contact sites.

J Cell Biol 2019 03 7;218(3):729-731. Epub 2019 Feb 7.

Cell Death Research & Therapy Laboratory (CDRT), Department of Cellular and Molecular Medicine, KU Leuven University of Leuven, Leuven, Belgium

ER-Golgi contact sites regulate lipid homeostasis and trafficking across the trans-Golgi network. However, their molecular nature is elusive. In this issue, Venditti et al. (2019. https://doi.org/10.1083/jcb.201812020 and https://doi.org/10.1083/jcb.201812021) shine new light on the molecular determinants coupling lipid exchange and cargo exit with maintenance of ER-Golgi contacts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1083/jcb.201901039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6400561PMC
March 2019

Autophagy in endothelial cells and tumor angiogenesis.

Cell Death Differ 2019 03 28;26(4):665-679. Epub 2019 Jan 28.

Cell Death Research & Therapy (CDRT) Laboratory, Department for Cellular and Molecular Medicine, KU Leuven University of Leuven, Leuven, Belgium.

In mammalian cells, autophagy is the major pathway for the degradation and recycling of obsolete and potentially noxious cytoplasmic materials, including proteins, lipids, and whole organelles, through the lysosomes. Autophagy maintains cellular and tissue homeostasis and provides a mechanism to adapt to extracellular cues and metabolic stressors. Emerging evidence unravels a critical function of autophagy in endothelial cells (ECs), the major components of the blood vasculature, which delivers nutrients and oxygen to the parenchymal tissue. EC-intrinsic autophagy modulates the response of ECs to various metabolic stressors and has a fundamental role in redox homeostasis and EC plasticity. In recent years moreover, genetic evidence suggests that autophagy regulates pathological angiogenesis, a hallmark of solid tumors. In the hypoxic, nutrient-deprived, and pro-angiogenic tumor microenvironment, heightened autophagy in the blood vessels is emerging as a critical mechanism enabling ECs to dynamically accommodate their higher bioenergetics demands to the extracellular environment and connect with other components of the tumor stroma through paracrine signaling. In this review, we provide an overview of the major cellular mechanisms regulated by autophagy in ECs and discuss their potential role in tumor angiogenesis, tumor growth, and response to anticancer therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41418-019-0287-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460396PMC
March 2019

NF-κB contributes to Smac mimetic-conferred protection from tunicamycin-induced apoptosis.

Apoptosis 2019 04;24(3-4):269-277

Institute for Experimental Cancer Research in Pediatrics, Goethe-University, Komturstr. 3a, 60528, Frankfurt, Germany.

Smac mimetics that deplete cellular inhibitor of apoptosis (cIAP) proteins have been shown to activate Nuclear Factor-kappa B (NF-κB). Here, we report that Smac mimetic-mediated activation of NF-κB contributes to the rescue of cancer cells from tunicamycin (TM)-triggered apoptosis. The prototypic Smac mimetic BV6 activates non-canonical and canonical NF-κB pathways, while TM has little effect on NF-κB signaling. Importantly, ectopic expression of dominant-negative IκBα superrepressor (IκBα-SR), which inhibits canonical and non-canonical NF-κB activation, significantly reversed this BV6-imposed protection against TM. Similarly, transient or stable knockdown of NF-κB-inducing kinase, which accumulated upon exposure to BV6 alone and in combination with TM, significantly counteracted BV6-mediated inhibition of TM-induced apoptosis. Interestingly, while cIAP2 was initially degraded upon BV6 treatment, it was subsequently upregulated in an NF-κB-dependent manner, as this restoration of cIAP2 expression was abolished in IκBα-SR-overexpressing cells. Interestingly, upon exposure to TM/BV6 apoptosis was significantly increased in cIAP2 knockdown cells. Furthermore, NF-κB inhibition partially prevented BV6-stimulated expression of Mcl-1 upon TM treatment. Consistently, Mcl-1 silencing significantly inhibited BV6-mediated protection from TM-induced apoptosis. Thus, NF-κB activation by Smac mimetic contributes to Smac mimetic-mediated protection against TM-induced apoptosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10495-018-1507-2DOI Listing
April 2019

Correction: BNIP3 modulates the interface between B16-F10 melanoma cells and immune cells.

Oncotarget 2018 12 11;9(97):37076. Epub 2018 Dec 11.

Laboratory for Cell Death Research and Therapy (CDRT), Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.

[This corrects the article DOI: 10.18632/oncotarget.24815.].
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.26474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6319346PMC
December 2018

PARL deficiency in mouse causes Complex III defects, coenzyme Q depletion, and Leigh-like syndrome.

Proc Natl Acad Sci U S A 2019 01 21;116(1):277-286. Epub 2018 Dec 21.

VIB Center for Brain and Disease Research, 3000 Leuven, Belgium;

The mitochondrial intramembrane rhomboid protease PARL has been implicated in diverse functions in vitro, but its physiological role in vivo remains unclear. Here we show that ablation in mouse causes a necrotizing encephalomyelopathy similar to Leigh syndrome, a mitochondrial disease characterized by disrupted energy production. Mice with conditional PARL deficiency in the nervous system, but not in muscle, develop a similar phenotype as germline KOs, demonstrating the vital role of PARL in neurological homeostasis. Genetic modification of two major PARL substrates, PINK1 and PGAM5, do not modify this severe neurological phenotype. brain mitochondria are affected by progressive ultrastructural changes and by defects in Complex III (CIII) activity, coenzyme Q (CoQ) biosynthesis, and mitochondrial calcium metabolism. PARL is necessary for the stable expression of TTC19, which is required for CIII activity, and of COQ4, which is essential in CoQ biosynthesis. Thus, PARL plays a previously overlooked constitutive role in the maintenance of the respiratory chain in the nervous system, and its deficiency causes progressive mitochondrial dysfunction and structural abnormalities leading to neuronal necrosis and Leigh-like syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1811938116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6320509PMC
January 2019

Phosphoprotein patterns predict trametinib responsiveness and optimal trametinib sensitisation strategies in melanoma.

Cell Death Differ 2019 08 15;26(8):1365-1378. Epub 2018 Oct 15.

ProtATonce Ltd, Science Park Demokritos, Athens, Greece.

Malignant melanoma is a highly aggressive form of skin cancer responsible for the majority of skin cancer-related deaths. Recent insight into the heterogeneous nature of melanoma suggests more personalised treatments may be necessary to overcome drug resistance and improve patient care. To this end, reliable molecular signatures that can accurately predict treatment responsiveness need to be identified. In this study, we applied multiplex phosphoproteomic profiling across a panel of 24 melanoma cell lines with different disease-relevant mutations, to predict responsiveness to MEK inhibitor trametinib. Supported by multivariate statistical analysis and multidimensional pattern recognition algorithms, the responsiveness of individual cell lines to trametinib could be predicted with high accuracy (83% correct predictions), independent of mutation status. We also successfully employed this approach to case specifically predict whether individual melanoma cell lines could be sensitised to trametinib. Our predictions identified that combining MEK inhibition with selective targeting of c-JUN and/or FAK, using siRNA-based depletion or pharmacological inhibitors, sensitised resistant cell lines and significantly enhanced treatment efficacy. Our study indicates that multiplex proteomic analyses coupled with pattern recognition approaches could assist in personalising trametinib-based treatment decisions in the future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41418-018-0210-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748097PMC
August 2019
-->