- Email: [email protected]
Autophagy and its link to the endoplasmic reticulum
M. Casal / Free Radical Biology and Medicine 120 (2018) S6–S23
L-50
A radical drug mechanism to inhibit tumor growth, metastasis, and resistance: Targeting lysosomal P-glycoprotein
S19
of cancer cells, metastasis, angiogenesis, tolerance to anticancer therapy, and self-renewal activity of stem-like cells.
E-mail address: [email protected]; [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.080
D.R. Richardson University of Sydney,Sydney, NSW, Australia
L-52
Multidrug resistance is a major obstacle in cancer treatment due to the ability of tumor cells to efflux drugs via transporters (e.g. P-glycoprotein (Pgp)). Although the mechanism of Pgp-mediated drug efflux is known at the plasma membrane, the functional role of intracellular Pgp is unclear. This investigation aimed to dissect the effects of tumor micro-environmental stress on Pgp expression, localization, and its role in MDR. These studies demonstrated that tumor micro-environment stressors induce Pgp-mediated drug resistance. This occurred by two mechanisms, where stressors induced: 1) rapid Pgp internalization and redistribution (within 1 h) and 2) hypoxia-inducible factor-1α expression after longer incubations (4–24 h), which upregulated Pgp and was accompanied by lysosomal biogenesis. These two mechanisms increased lysosomal Pgp and facilitated lysosomal accumulation of the Pgp substrate, doxorubicin, resulting in resistance. This was consistent with lysosomal Pgp transporting substrates into lysosomes. When stress stimuli increased lysosomal accumulation of the cytotoxic Pgp substrate, di-2pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), this resulted in the agent overcoming resistance. As such, a novel approach to overcoming resistance will be discussed.
Ferroptosis in carcinogenesis and tumor biology
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.079
Shinya Toyokuni Nagoya University Graduate School of Medicine, Nagoya, Japan
Excess iron is associated with carcinogenesis. Ferric nitrilotriacetateinduced renal cancers in wild-type rats reveal similar genetic alterations to those in humans. Ferroptosis may be defined as a form of regulated necrosis, characterized by lipid peroxidation through high iron/sulfur(antioxidants) ratio. Considering that cancer cells in general retain more catalytic Fe(II) than non-tumorous cells, many iron-induced carcinogenesis models, including asbestos-induced mesothelioma, suggest that cancer is a state of iron addiction with ferroptosis-resistance. Non-thermal plasma (NTP) is a novel physical technique that emits abundant electrons, leading to a variety of ROS products by reaction with atmospheric oxygen. Exposure of NTP to biomolecules, cells or tissues causes oxidative stress in situ, resulting in DNA breaks and lipid peroxidation products, such as HNE. We found that NTP exposure is highly dependent on Fe(II) in situ, causing cancer cell-specific ferroptosis, which was associated with autophagy activation and lysosome genesis. Thus, we discuss the role of phlebotomy for cancer prevention and the use of NTP as a new cancer therapy.
E-mail address: [email protected] L-51
Differential roles for the redox sensitive transcription factor Nrf2 in carcinogenesis
References Toyokuni S et al., FRBM 108: 610, 2017; Shi L et al., FRBM 108: 904, 2017; Stockwell BR, et al. Cell 171: 273, 2017.
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.081
Hoang-Kieu-Chi Ngo, Do-Hee Kim, Jinyoung Suh, Sin-Aye Park, Su Jung Kim, Soma Saeidi, Hye-Kyung Na, Young-Joon Surh Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
L-53
Autophagy and its link to the endoplasmic reticulum Nuclear factor E2-related factor 2 (Nrf2) is a redox-sensitive transcription factor regulating the expression of a battery of genes encoding antioxidant and carcinogen detoxifying enzymes. In contrast to its tumor suppressive functions in normal cells, Nrf2 facilitates tumor growth and progression through metabolic reprograming in some cancer cells. Our previous study has demonstrated that 15-deoxy-Δ12,14-prostaglandin J2 and 4-hydroxyestradiol induce overactivation of Nrf2 and consequently overexpression of its target protein, heme oxygenase-1 (HO-1), in human breast cancer cells. More recently, we have demonstrated the involvement of Nrf2 in experimentally induced hepatocarcinogenesis (N.H.K. Chi et al., Cancer Res., 2017). In this context, the cellular stress response or cytoprotective signaling mediated via the Nrf2-HO1 axis is hijacked by cancer cells. This may facilitate the remodeling of the tumor microenvironment making it advantageous for the autonomic growth
Veit Goder Department of Genetics, University of Seville, Seville, Spain
Autophagy is a conserved cellular process characterized by the de novo generation of double-membraned autophagosomes. It plays a significant role in promoting survival during periods of starvation when the increased generation of autophagosomes leads to the enclosure of bulk cytosol and the transport to the vacuole/lysosome where the protein content is degraded down to amino acids for reuse. More recently it was found that autophagy is also vital in cellular quality control by removing
S20
M. Casal / Free Radical Biology and Medicine 120 (2018) S6–S23
aggregated proteins and damaged or superfluous organelles. Given that autophagy is broadly involved in many key aspects of cellular homeostasis, it is not surprising that its dysfunction attributes to various human diseases, among them neurodegenerative diseases and cancer. The biogenesis of autophagosomes starts from a poorly characterized initial membrane structure, the phagophore, and proceeds through phagophore expansion, i.e. the growth of autophagosomal membranes, by an equally undefined mechanism. We study the connection of the endoplasmic reticulum (ER) to autophagosome biogenesis during starvation using yeast as model organism. We will present recent data and provide a model for how specific vesicular traffic from the ER provides membranes to autophagosomes.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.082
L-54
Free radicals at the crossroads of autophagy and immunity
As a stress-induced mechanism, autophagy provides energy and essential biomolecules through degradation of cellular cytoplasmic constituents, thus helping cells to adapt to nutrient scarcity. Autophagy regulation by nutrient availability has been evolutionarily conserved from the simplest eukaryotic organisms, as yeasts, to mammals or plants. Apart from this ancient energy-providing role, autophagy has evolved to act as a basal, constitutively-activated, catabolic route preventing accumulation of detrimental intracellular structures, thus keeping cells homeostasis and organism integrity. To better understand autophagy's roles in higher eukaryotes, a variety of autophagy-deficient mice have currently been generated. The study of these modes has provided clues on how basal autophagy sustains cellular health, tissue-specific functions and organismal response to environmental factors. We will describe how the study of autophagy-deficient animal models has improved our understanding on how this catabolic route protects cells, tissues and organisms either as a constitutive or inducible pathway. Finally, we will discuss the differences between animal models with either total or partial autophagy inactivation and explain the advantages for each of these complementary strategies.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.084
Jennifer Martinez NIEHS, Research Triangle Park, NC, USA
L-56
The role of autophagy and cancer We now recognize that the autophagy machinery functions in a multitude of non-canonical biological pathways, including the host defense to extracellular threats, such as pathogens. We have identified a form of non-canonical autophagy termed LC3-associated phagocytosis (LAP), wherein phagosomes containing engulfed particles, including pathogens and dying cells, recruit elements of the autophagy pathway to facilitate phagosome maturation, digestion of cargo, and modulation of innate immunity. We have characterized Rubicon as a LAP-specific, autophagy-independent molecule, allowing the study of the unique role of LAP. To better understand host factors that may play a role in infection, we investigated the role of Rubicon during Salmonella enterica Typhimurium infection. Macrophages lacking Rubicon failed to control S. enterica Typhimurium and produced a markedly decreased ability to produce free radicals during infection compared to wild type macrophages. Rubicondeficient cells also displayed a hyperactivation of canonical Nf-Kb signaling, demonstrating a failure to coordinate an appropriate inflammatory reaction. Rubicon-/mice demonstrate that Rubicon is essential for several aspects of pathology including replication control and immunological response.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.083
L-55
Autophagy deficient mice as a model for studying stress-induced autophagy in vivo Guillermo Mariño University of Oviedo / Principality of Asturias Sanitary Research Institute (ISPA), Oviedo, Spain
Guillermo Velasco Department of Biochemistry and Molecular Biology I, School of Biology, Complutense University and Instituto de Investigaciones Sanitarias San Carlos (IdISSC), Madrid, Spain
Autophagy is the main cellular degradation pathway for the clearance of damaged or superfluous proteins and organelles and represents the principle catabolic process regulating cellular homeostasis and organelle and protein turnover. Besides its role in cellular homeostasis, autophagy can be a form of programmed cell death or play a cytoprotective role, for example in situations of nutrient starvation. Accordingly, autophagy plays a dual role in cancer as this cellular process may help to overcome the stress evoked at the initial steps of tumorigenesis or work as a tumor suppressor mechanism. Moreover, different anticancer treatments activate autophagy in tumor cells, which either enhance cancer cell death or act as a mechanism of resistance to chemotherapy. Prior work by our group showed that Δ9-tetrahydrocannabinol (THC, the main active component of marijuana) triggers autophagy-mediated cancer cell death. In this presentation I will summarize several recent findings supporting that the modification of the sphingolipid metabolism of cancer cells by cannabinoids plays a pivotal role in the stimulation of autophagy-mediated cancer cell death.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.085
L-50
A radical drug mechanism to inhibit tumor growth, metastasis, and resistance: Targeting lysosomal P-glycoprotein
S19
of cancer cells, metastasis, angiogenesis, tolerance to anticancer therapy, and self-renewal activity of stem-like cells.
E-mail address: [email protected]; [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.080
D.R. Richardson University of Sydney,Sydney, NSW, Australia
L-52
Multidrug resistance is a major obstacle in cancer treatment due to the ability of tumor cells to efflux drugs via transporters (e.g. P-glycoprotein (Pgp)). Although the mechanism of Pgp-mediated drug efflux is known at the plasma membrane, the functional role of intracellular Pgp is unclear. This investigation aimed to dissect the effects of tumor micro-environmental stress on Pgp expression, localization, and its role in MDR. These studies demonstrated that tumor micro-environment stressors induce Pgp-mediated drug resistance. This occurred by two mechanisms, where stressors induced: 1) rapid Pgp internalization and redistribution (within 1 h) and 2) hypoxia-inducible factor-1α expression after longer incubations (4–24 h), which upregulated Pgp and was accompanied by lysosomal biogenesis. These two mechanisms increased lysosomal Pgp and facilitated lysosomal accumulation of the Pgp substrate, doxorubicin, resulting in resistance. This was consistent with lysosomal Pgp transporting substrates into lysosomes. When stress stimuli increased lysosomal accumulation of the cytotoxic Pgp substrate, di-2pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), this resulted in the agent overcoming resistance. As such, a novel approach to overcoming resistance will be discussed.
Ferroptosis in carcinogenesis and tumor biology
E-mail address: [email protected] http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.079
Shinya Toyokuni Nagoya University Graduate School of Medicine, Nagoya, Japan
Excess iron is associated with carcinogenesis. Ferric nitrilotriacetateinduced renal cancers in wild-type rats reveal similar genetic alterations to those in humans. Ferroptosis may be defined as a form of regulated necrosis, characterized by lipid peroxidation through high iron/sulfur(antioxidants) ratio. Considering that cancer cells in general retain more catalytic Fe(II) than non-tumorous cells, many iron-induced carcinogenesis models, including asbestos-induced mesothelioma, suggest that cancer is a state of iron addiction with ferroptosis-resistance. Non-thermal plasma (NTP) is a novel physical technique that emits abundant electrons, leading to a variety of ROS products by reaction with atmospheric oxygen. Exposure of NTP to biomolecules, cells or tissues causes oxidative stress in situ, resulting in DNA breaks and lipid peroxidation products, such as HNE. We found that NTP exposure is highly dependent on Fe(II) in situ, causing cancer cell-specific ferroptosis, which was associated with autophagy activation and lysosome genesis. Thus, we discuss the role of phlebotomy for cancer prevention and the use of NTP as a new cancer therapy.
E-mail address: [email protected] L-51
Differential roles for the redox sensitive transcription factor Nrf2 in carcinogenesis
References Toyokuni S et al., FRBM 108: 610, 2017; Shi L et al., FRBM 108: 904, 2017; Stockwell BR, et al. Cell 171: 273, 2017.
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.081
Hoang-Kieu-Chi Ngo, Do-Hee Kim, Jinyoung Suh, Sin-Aye Park, Su Jung Kim, Soma Saeidi, Hye-Kyung Na, Young-Joon Surh Tumor Microenvironment Global Core Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
L-53
Autophagy and its link to the endoplasmic reticulum Nuclear factor E2-related factor 2 (Nrf2) is a redox-sensitive transcription factor regulating the expression of a battery of genes encoding antioxidant and carcinogen detoxifying enzymes. In contrast to its tumor suppressive functions in normal cells, Nrf2 facilitates tumor growth and progression through metabolic reprograming in some cancer cells. Our previous study has demonstrated that 15-deoxy-Δ12,14-prostaglandin J2 and 4-hydroxyestradiol induce overactivation of Nrf2 and consequently overexpression of its target protein, heme oxygenase-1 (HO-1), in human breast cancer cells. More recently, we have demonstrated the involvement of Nrf2 in experimentally induced hepatocarcinogenesis (N.H.K. Chi et al., Cancer Res., 2017). In this context, the cellular stress response or cytoprotective signaling mediated via the Nrf2-HO1 axis is hijacked by cancer cells. This may facilitate the remodeling of the tumor microenvironment making it advantageous for the autonomic growth
Veit Goder Department of Genetics, University of Seville, Seville, Spain
Autophagy is a conserved cellular process characterized by the de novo generation of double-membraned autophagosomes. It plays a significant role in promoting survival during periods of starvation when the increased generation of autophagosomes leads to the enclosure of bulk cytosol and the transport to the vacuole/lysosome where the protein content is degraded down to amino acids for reuse. More recently it was found that autophagy is also vital in cellular quality control by removing
S20
M. Casal / Free Radical Biology and Medicine 120 (2018) S6–S23
aggregated proteins and damaged or superfluous organelles. Given that autophagy is broadly involved in many key aspects of cellular homeostasis, it is not surprising that its dysfunction attributes to various human diseases, among them neurodegenerative diseases and cancer. The biogenesis of autophagosomes starts from a poorly characterized initial membrane structure, the phagophore, and proceeds through phagophore expansion, i.e. the growth of autophagosomal membranes, by an equally undefined mechanism. We study the connection of the endoplasmic reticulum (ER) to autophagosome biogenesis during starvation using yeast as model organism. We will present recent data and provide a model for how specific vesicular traffic from the ER provides membranes to autophagosomes.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.082
L-54
Free radicals at the crossroads of autophagy and immunity
As a stress-induced mechanism, autophagy provides energy and essential biomolecules through degradation of cellular cytoplasmic constituents, thus helping cells to adapt to nutrient scarcity. Autophagy regulation by nutrient availability has been evolutionarily conserved from the simplest eukaryotic organisms, as yeasts, to mammals or plants. Apart from this ancient energy-providing role, autophagy has evolved to act as a basal, constitutively-activated, catabolic route preventing accumulation of detrimental intracellular structures, thus keeping cells homeostasis and organism integrity. To better understand autophagy's roles in higher eukaryotes, a variety of autophagy-deficient mice have currently been generated. The study of these modes has provided clues on how basal autophagy sustains cellular health, tissue-specific functions and organismal response to environmental factors. We will describe how the study of autophagy-deficient animal models has improved our understanding on how this catabolic route protects cells, tissues and organisms either as a constitutive or inducible pathway. Finally, we will discuss the differences between animal models with either total or partial autophagy inactivation and explain the advantages for each of these complementary strategies.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.084
Jennifer Martinez NIEHS, Research Triangle Park, NC, USA
L-56
The role of autophagy and cancer We now recognize that the autophagy machinery functions in a multitude of non-canonical biological pathways, including the host defense to extracellular threats, such as pathogens. We have identified a form of non-canonical autophagy termed LC3-associated phagocytosis (LAP), wherein phagosomes containing engulfed particles, including pathogens and dying cells, recruit elements of the autophagy pathway to facilitate phagosome maturation, digestion of cargo, and modulation of innate immunity. We have characterized Rubicon as a LAP-specific, autophagy-independent molecule, allowing the study of the unique role of LAP. To better understand host factors that may play a role in infection, we investigated the role of Rubicon during Salmonella enterica Typhimurium infection. Macrophages lacking Rubicon failed to control S. enterica Typhimurium and produced a markedly decreased ability to produce free radicals during infection compared to wild type macrophages. Rubicondeficient cells also displayed a hyperactivation of canonical Nf-Kb signaling, demonstrating a failure to coordinate an appropriate inflammatory reaction. Rubicon-/mice demonstrate that Rubicon is essential for several aspects of pathology including replication control and immunological response.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.083
L-55
Autophagy deficient mice as a model for studying stress-induced autophagy in vivo Guillermo Mariño University of Oviedo / Principality of Asturias Sanitary Research Institute (ISPA), Oviedo, Spain
Guillermo Velasco Department of Biochemistry and Molecular Biology I, School of Biology, Complutense University and Instituto de Investigaciones Sanitarias San Carlos (IdISSC), Madrid, Spain
Autophagy is the main cellular degradation pathway for the clearance of damaged or superfluous proteins and organelles and represents the principle catabolic process regulating cellular homeostasis and organelle and protein turnover. Besides its role in cellular homeostasis, autophagy can be a form of programmed cell death or play a cytoprotective role, for example in situations of nutrient starvation. Accordingly, autophagy plays a dual role in cancer as this cellular process may help to overcome the stress evoked at the initial steps of tumorigenesis or work as a tumor suppressor mechanism. Moreover, different anticancer treatments activate autophagy in tumor cells, which either enhance cancer cell death or act as a mechanism of resistance to chemotherapy. Prior work by our group showed that Δ9-tetrahydrocannabinol (THC, the main active component of marijuana) triggers autophagy-mediated cancer cell death. In this presentation I will summarize several recent findings supporting that the modification of the sphingolipid metabolism of cancer cells by cannabinoids plays a pivotal role in the stimulation of autophagy-mediated cancer cell death.
E-mail address: [email protected]
http://dx.doi.org/10.1016/j.freeradbiomed.2018.04.085