scholarly journals The cytoplasmic DNA sensor cGAS promotes mitotic cell death

2017 ◽  
Author(s):  
Christian Zierhut ◽  
Hironori Funabiki

AbstractThe cyclic GMP-AMP (cGAMP) synthase cGAS counteracts infections by detecting and binding foreign cytoplasmic DNA1. DNA-induced synthesis of cGAMP activates innate immune signalling and apoptosis through the cGAMP receptor STING and the downstream effector IRF31–7. During interphase the nuclear envelope protects chromosomal self-DNA from cGAS, but the consequences of exposing chromosomes to cGAS following mitotic nuclear envelope disassembly are unknown. Here we demonstrate that cGAS associates with chromosomes during mitosis and binds nucleosomes with even higher affinity than naked DNA in vitro. Nucleosomes nevertheless competitively inhibit the DNA-dependent stimulation of cGAS, and accordingly, chromosomal cGAS does not affect mitotic progression under normal conditions. This suggests that nucleosomes prevent the inappropriate activation of cGAS during mitosis by acting as a signature of self-DNA. During prolonged mitotic arrest, however, cGAS becomes activated to promote cell death, limiting the fraction of cells that can survive and escape mitotic arrest induced by the chemotherapeutic drug taxol. Induction of mitotic cell death involves cGAMP synthesis by cGAS, as well as signal transduction to IRF3 by STING. We thus propose that cGAS plays a previously unappreciated role in guarding against mitotic errors, promoting cell death during prolonged mitotic arrest. Our data also indicate that the cGAS pathway, whose activity differs widely among cell lines, impacts cell fate determination upon treatment with taxol and other anti-mitotic drugs. Thus, we propose the innate immune system may be harnessed to selectively target cells with mitotic abnormalities.

2018 ◽  
Author(s):  
Kai T. Richter ◽  
Yvonne T. Kschonsak ◽  
Barbara Vodicska ◽  
Ingrid Hoffmann

SUMMARYCell fate decision upon prolonged mitotic arrest induced by microtubule targeting agents depends on the activity of the tumor suppressor and F-box protein FBXW7. FBXW7 promotes mitotic cell death and prevents premature escape from mitosis through mitotic slippage. Mitotic slippage is a process that can cause chemoresistance and tumor relapse. Therefore, understanding the mechanisms that regulate the balance between mitotic cell death and mitotic slippage is an important task. Here we report that FBXW7 protein levels markedly decline during extended mitotic arrest. FBXO45 binds to a conserved acidic N-terminal motif of FBXW7 specifically under a prolonged delay in mitosis, leading to ubiquitylation and subsequent proteasomal degradation of FBXW7 by the FBXO45-MYCBP2 E3 ubiquitin ligase. Moreover, we find that FBXO45-MYCBP2 counteracts FBXW7 in that it promotes mitotic slippage and prevents cell death in mitosis. Targeting this interaction represents a promising strategy to prevent chemotherapy resistance.


2018 ◽  
Vol 115 (46) ◽  
pp. E10849-E10858 ◽  
Author(s):  
Yan Li ◽  
Jingjing Jiang ◽  
Wei Liu ◽  
Hui Wang ◽  
Lei Zhao ◽  
...  

The metabolic regulation of cell death is sophisticated. A growing body of evidence suggests the existence of multiple metabolic checkpoints that dictate cell fate in response to metabolic fluctuations. However, whether microRNAs (miRNAs) are able to respond to metabolic stress, reset the threshold of cell death, and attempt to reestablish homeostasis is largely unknown. Here, we show that miR-378/378* KO mice cannot maintain normal muscle weight and have poor running performance, which is accompanied by impaired autophagy, accumulation of abnormal mitochondria, and excessive apoptosis in skeletal muscle, whereas miR-378 overexpression is able to enhance autophagy and repress apoptosis in skeletal muscle of mice. Our in vitro data show that metabolic stress-responsive miR-378 promotes autophagy and inhibits apoptosis in a cell-autonomous manner. Mechanistically, miR-378 promotes autophagy initiation through the mammalian target of rapamycin (mTOR)/unc-51-like autophagy activating kinase 1 (ULK1) pathway and sustains autophagy via Forkhead box class O (FoxO)-mediated transcriptional reinforcement by targeting phosphoinositide-dependent protein kinase 1 (PDK1). Meanwhile, miR-378 suppresses intrinsic apoptosis initiation directly through targeting an initiator caspase—Caspase 9. Thus, we propose that miR-378 is a critical component of metabolic checkpoints, which integrates metabolic information into an adaptive response to reduce the propensity of myocytes to undergo apoptosis by enhancing the autophagic process and blocking apoptotic initiation. Lastly, our data suggest that inflammation-induced down-regulation of miR-378 might contribute to the pathogenesis of muscle dystrophy.


2007 ◽  
Vol 178 (2) ◽  
pp. 283-296 ◽  
Author(s):  
Yohei Niikura ◽  
Amruta Dixit ◽  
Ray Scott ◽  
Guy Perkins ◽  
Katsumi Kitagawa

The spindle checkpoint that monitors kinetochore–microtubule attachment has been implicated in tumorigenesis; however, the relation between the spindle checkpoint and cell death remains obscure. In BUB1-deficient (but not MAD2-deficient) cells, conditions that activate the spindle checkpoint (i.e., cold shock or treatment with nocodazole, paclitaxel, or 17-AAG) induced DNA fragmentation during early mitosis. This mitotic cell death was independent of caspase activation; therefore, we named it caspase-independent mitotic death (CIMD). CIMD depends on p73, a homologue of p53, but not on p53. CIMD also depends on apoptosis-inducing factor and endonuclease G, which are effectors of caspase-independent cell death. Treatment with nocodazole, paclitaxel, or 17-AAG induced CIMD in cell lines derived from colon tumors with chromosome instability, but not in cells from colon tumors with microsatellite instability. This result was due to low BUB1 expression in the former cell lines. When BUB1 is completely depleted, aneuploidy rather than CIMD occurs. These results suggest that cells prone to substantial chromosome missegregation might be eliminated via CIMD.


Cell ◽  
2019 ◽  
Vol 178 (2) ◽  
pp. 302-315.e23 ◽  
Author(s):  
Christian Zierhut ◽  
Norihiro Yamaguchi ◽  
Maria Paredes ◽  
Ji-Dung Luo ◽  
Thomas Carroll ◽  
...  

2020 ◽  
Vol 27 (7) ◽  
pp. 2081-2098 ◽  
Author(s):  
Ishani Das ◽  
Helge Gad ◽  
Lars Bräutigam ◽  
Linda Pudelko ◽  
Rainer Tuominen ◽  
...  

AbstractCutaneous malignant melanoma (CMM) is the deadliest form of skin cancer and clinically challenging due to its propensity to develop therapy resistance. Reactive oxygen species (ROS) can induce DNA damage and play a significant role in CMM. MTH1 protein protects from ROS damage and is often overexpressed in different cancer types including CMM. Herein, we report that MTH1 inhibitor TH1579 induced ROS levels, increased DNA damage responses, caused mitotic arrest and suppressed CMM proliferation leading to cell death both in vitro and in an in vivo xenograft CMM zebrafish disease model. TH1579 was more potent in abrogating cell proliferation and inducing cell death in a heterogeneous co-culture setting when compared with CMM standard treatments, vemurafenib or trametinib, showing its broad anticancer activity. Silencing MTH1 alone exhibited similar cytotoxic effects with concomitant induction of mitotic arrest and ROS induction culminating in cell death in most CMM cell lines tested, further emphasizing the importance of MTH1 in CMM cells. Furthermore, overexpression of receptor tyrosine kinase AXL, previously demonstrated to contribute to BRAF inhibitor resistance, sensitized BRAF mutant and BRAF/NRAS wildtype CMM cells to TH1579. AXL overexpression culminated in increased ROS levels in CMM cells. Moreover, silencing of a protein that has shown opposing effects on cell proliferation, CAV-1, decreased sensitivity to TH1579 in a BRAF inhibitor resistant cell line. AXL-MTH1 and CAV-1-MTH1 mRNA expressions were correlated as seen in CMM clinical samples. Finally, TH1579 in combination with BRAF inhibitor exhibited a more potent cell killing effect in BRAF mutant cells both in vitro and in vivo. In summary, we show that TH1579-mediated efficacy is independent of BRAF/NRAS mutational status but dependent on the expression of AXL and CAV-1.


Reproduction ◽  
2004 ◽  
Vol 128 (3) ◽  
pp. 281-291 ◽  
Author(s):  
Andrea Jurisicova ◽  
Beth M Acton

Human preimplantation embryo development is prone to high rates of early embryo wastage, particularly under currentin vitroculture conditions. There are many possible underlying causes for embryo demise, including DNA damage, poor embryo metabolism and the effect of suboptimal culture media, all of which could result in an imbalance in gene expression and the failed execution of basic embryonic decisions. In view of the complex interactions involved in embryo development, a thorough understanding of these parameters is essential to improving embryo quality. An increasing body of evidence indicates that cell fate (i.e. survival/differentiation or death) is determined by the outcome of specific intracellular interactions between pro- and anti-apoptotic proteins, many of which are expressed during oocyte and preimplantation embryo development. The recent availability of mutant mice lacking expression of various genes involved in the regulation of cell survival has enabled rapid progress towards identifying those molecules that are functionally important for normal oocyte and preimplantation embryo development. In this review we will discuss the current understanding of the regulation of cell death gene expression during preimplantation embryo development, with a focus on human embryology and a discussion of animal models where appropriate.


2019 ◽  
Vol 8 (4) ◽  
pp. e1565859 ◽  
Author(s):  
Maxine Bauzon ◽  
Penelope M. Drake ◽  
Robyn M. Barfield ◽  
Brandon M. Cornali ◽  
Igor Rupniewski ◽  
...  

2003 ◽  
Vol 104 (5) ◽  
pp. 455-466 ◽  
Author(s):  
Duncan S. COLE ◽  
B. Paul MORGAN

Complement is a central component of the innate immune system involved in protection against pathogens. For many years, complement has been known to cause death of targets, either indirectly by attracting and activating phagocytes or directly by formation of a membrane pore, the membrane attack complex. More recently, it has been recognized that complement may cause other ‘non-classical’ effects that may not directly be aimed at killing of pathogens. Products of complement activation collaborate with the adaptive immune system to enhance responses to antigens. The membrane attack complex of complement, apart from lysing cells, can also trigger diverse events in target cells that include cell activation, proliferation, resistance to subsequent complement attack and either resistance to, or induction of, apoptosis. Various complement products play important roles in signalling for clearance by phagocytes of apoptotic self cells. Here we review some of these non-classical activities of complement and stress the roles that they may play in maintaining the integrity of the organism.


2009 ◽  
Vol 31 (5) ◽  
pp. 393-405
Author(s):  
Leyuan Liu ◽  
Rui Xie ◽  
Chaofeng Yang ◽  
Wallace L. McKeehan

Background: Survival and evolution of aneuploid cells after an asymmetric segregation of chromosomes at mitosis may be the common initiating event and underlying cause of the genetic diversity and adaptability of cancers. We hypothesize that mechanisms exist to detect impending aneuploidy and prevent it before completion of an aberrant mitosis.Methods: The distribution of isoforms of C19ORF5, an interactive partner with mitochondria-associated LRPPRC and tumor suppressor RASSF1A, state of spindle microtubules and mitochondrial aggregation was analyzed in synchronized mitotic cells and cells stalled in mitosis after treatment with paclitaxel.Results: C19ORF5 distributed broadly across the mitotic spindle and reversibly accumulated during reversible mitotic arrest. Prolonged stabilization of microtubules caused an accumulation of a C19ORF5 product with dual MAP and MtAP properties that caused irreversible aggregation of mitochondria and death of mitotic cells.Conclusions: Dual function microtubule-associated (MAP) and mitochondria-associated (MtAP) proteins generated by prolonged mitotic arrest trigger mitochondrial-induced mitotic cell death. This is a potential mechanism to prevent minimal survivable aneuploidy resulting from an aberrant cell division and cancers in general at their earliest common origin.


2021 ◽  
Author(s):  
Hanna S. Hong ◽  
Nneka E. Mbah ◽  
Mengrou Shan ◽  
Kristen Loesel ◽  
Lin Lin ◽  
...  

AbstractApoptotic cell death is a cell-intrinsic, immune tolerance mechanism that regulates the magnitude and resolution of T cell-mediated responses. Evasion of apoptosis is critical for the generation of memory T cells, as well as autoimmune T cells, and knowledge of the mechanisms that enable resistance to apoptosis will provide insight into ways to modulate their activity during protective and pathogenic responses. IL-17-producing CD4 T cells (TH17s) are long-lived, memory cells. These features enable their role in host defense, chronic inflammatory disorders, and anti-tumor immunity. A growing number of reports now indicate that TH17s in vivo require mitochondrial oxidative phosphorylation (OXPHOS), a metabolic phenotype that is poorly induced in vitro. To elucidate the role of OXPHOS in TH17 processes, we developed a system to polarize TH17s that metabolically resembled their in vivo counterparts. We discovered that directing TH17s to use OXPHOS promotes mitochondrial fitness, glutamine anaplerosis, and an anti-apoptotic phenotype marked by high BCL-XL and low BIM. Through competitive co-transfer experiments and tumor studies, we further revealed how OXPHOS protects TH17s from cell death while enhancing their persistence in the periphery and tumor microenvironment. Together, our work demonstrates a non-classical role of metabolism in regulating TH17 cell fate and highlights the potential for therapies that target OXPHOS in TH17-driven diseases.


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