scholarly journals Dual Function Microtubule- and Mitochondria-Associated Proteins Mediate Mitotic Cell Death

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.

2002 ◽  
Vol 159 (4) ◽  
pp. 549-555 ◽  
Author(s):  
Jennifer G. DeLuca ◽  
Ben Moree ◽  
Jennifer M. Hickey ◽  
John V. Kilmartin ◽  
E.D. Salmon

Identification of proteins that couple kinetochores to spindle microtubules is critical for understanding how accurate chromosome segregation is achieved in mitosis. Here we show that the protein hNuf2 specifically functions at kinetochores for stable microtubule attachment in HeLa cells. When hNuf2 is depleted by RNA interference, spindle formation occurs normally as cells enter mitosis, but kinetochores fail to form their attachments to spindle microtubules and cells block in prometaphase with an active spindle checkpoint. Kinetochores depleted of hNuf2 retain the microtubule motors CENP-E and cytoplasmic dynein, proteins previously implicated in recruiting kinetochore microtubules. Kinetochores also retain detectable levels of the spindle checkpoint proteins Mad2 and BubR1, as expected for activation of the spindle checkpoint by unattached kinetochores. In addition, the cell cycle block produced by hNuf2 depletion induces mitotic cells to undergo cell death. These data highlight a specific role for hNuf2 in kinetochore–microtubule attachment and suggest that hNuf2 is part of a molecular linker between the kinetochore attachment site and tubulin subunits within the lattice of attached plus ends.


2019 ◽  
Author(s):  
Santiago Gisler ◽  
Ana Rita R. Maia ◽  
Gayathri Chandrasekaran ◽  
Maarten van Lohuizen

AbstractBMI1 is a core protein of the polycomb repressive complex 1 (PRC1) that is overexpressed in several cancer types, making it a promising target for cancer therapies. However, the underlying mechanisms and interactions associated with BMI1-induced tumorigenesis are often context-dependent and complex. Here, we performed a drug resistance screen on mutagenized human haploid HAP1 cells treated with the BMI1 inhibitor PTC-318 to find new genetic and mechanistic features associated with BMI1-dependent cancer cell proliferation. Our screen identified NUMA1-mutations as the most significant inducer of PTC-318 cell death resistance. Independent validations on NUMA1-proficient HAP1 and non-small cell lung cancer cell lines exposed to BMI1 inhibition by PTC-318 or BMI1 knockdown resulted in cell death following mitotic arrest. Interestingly, cells with CRISPR-Cas9 derived NUMA1 knockout also showed a mitotic arrest phenotype following BMI1 inhibition but, contrary to cells with wildtype NUMA1, these cells were resistant to BMI1-dependent cell death. The current study brings new insights to BMI1 inhibition-induced mitotic lethality in cancer cells and presents a previously unknown role for NUMA1 in this process.


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.


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.


2006 ◽  
Vol 172 (7) ◽  
pp. 1009-1022 ◽  
Author(s):  
Jawdat Al-Bassam ◽  
Mark van Breugel ◽  
Stephen C. Harrison ◽  
Anthony Hyman

Stu2p from budding yeast belongs to the conserved Dis1/XMAP215 family of microtubule-associated proteins (MAPs). The common feature of proteins in this family is the presence of HEAT repeat–containing TOG domains near the NH2 terminus. We have investigated the functions of the two TOG domains of Stu2p in vivo and in vitro. Our data suggest that Stu2p regulates microtubule dynamics through two separate activities. First, Stu2p binds to a single free tubulin heterodimer through its first TOG domain. A large conformational transition in homodimeric Stu2p from an open structure to a closed one accompanies the capture of a single free tubulin heterodimer. Second, Stu2p has the capacity to associate directly with microtubule ends, at least in part, through its second TOG domain. These two properties lead to the stabilization of microtubules in vivo, perhaps by the loading of tubulin dimers at microtubule ends. We suggest that this mechanism of microtubule regulation is a conserved feature of the Dis1/XMAP215 family of MAPs.


Author(s):  
Sandro Sacchi ◽  
Paola Sena ◽  
Chiara Addabbo ◽  
Erika Cuttone ◽  
Antonio La Marca

AbstractBackgroundGonadotrophins exert their functions by binding follicle-stimulating hormone receptor (FSHR) or luteinizing hormone and human chorionic gonadotropin receptor (LHCGR) present on endometrium. Within ovaries, FSH induces autophagy and apoptosis of granulosa cells leading to atresia of non-growing follicles, whereas hCG and LH have anti-apoptotic functions. Endometrial cells express functioning gonadotrophin receptors. The objective of this study was to analyze the effect of gonadotrophins on physiology and endometrial cells survival.Materials and methodsCollected endometria were incubated for 48 or 72 h with 100 ng/mL of recombinant human FSH (rhFSH), recombinant human LH (rhLH) or highly purified hCG (HPhCG) alone or combined. Controls omitted gonadotrophins. The effect of gonadotrophins on cytochrome P450 family 11 subfamily A polypeptide 1 (CYP11A1), hypoxia inducible factor 1α (HIF1A), and cell-death-related genes expression was evaluated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Immunohistochemistry for microtubule-associated proteins 1A/1B light chain 3B (MAP1LC3B) and apoptotic protease activating factor 1 (APAF-1) was performed.ResultsGonadotrophins are able to modulate the endometrial cells survival. FSH induced autophagy and apoptosis by increasing the relative expression of MAP1LC3B and FAS receptor. In FSH-treated samples, expression of apoptosis marker APAF-1 was detected and co-localized on autophagic cells. hCG and LH does not modulate the expression of cell-death-related genes while the up-regulation of pro-proliferative epiregulin gene was observed. When combined with FSH, hCG and LH prevent autophagy and apoptosis FSH-induced.ConclusionsDifferent gonadotrophins specifically affect endometrial cells viability differently: FSH promotes autophagy and apoptosis while LH and hCG alone or combined with rhFSH does not.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ruoxi Zhang ◽  
Rui Kang ◽  
Daolin Tang

AbstractCell death and immune response are at the core of life. In past decades, the endoplasmic reticulum (ER) protein STING1 (also known as STING or TMEM173) was found to play a fundamental role in the production of type I interferons (IFNs) and pro-inflammatory cytokines in response to DNA derived from invading microbial pathogens or damaged hosts by activating multiple transcription factors. In addition to this well-known function in infection, inflammation, and immunity, emerging evidence suggests that the STING1-dependent signaling network is implicated in health and disease by regulating autophagic degradation or various cell death modalities (e.g., apoptosis, necroptosis, pyroptosis, ferroptosis, mitotic cell death, and immunogenic cell death [ICD]). Here, we outline the latest advances in our understanding of the regulating mechanisms and signaling pathways of STING1 in autophagy and cell death, which may shed light on new targets for therapeutic interventions.


Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 678 ◽  
Author(s):  
Adrien Procureur ◽  
Audrey Simonaggio ◽  
Jean-Emmanuel Bibault ◽  
Stéphane Oudard ◽  
Yann-Alexandre Vano

The immunogenic cell death (ICD) is defined as a regulated cell death able to induce an adaptive immunity. It depends on different parameters including sufficient antigenicity, adjuvanticity and favorable microenvironment conditions. Radiation therapy (RT), a pillar of modern cancer treatment, is being used in many tumor types in curative, (neo) adjuvant, as well as metastatic settings. The anti-tumor effects of RT have been traditionally attributed to the mitotic cell death resulting from the DNA damages triggered by the release of reactive oxygen species. Recent evidence suggests that RT may also exert its anti-tumor effect by recruiting tumor-specific immunity. RT is able to induce the release of tumor antigens, to act as an immune adjuvant and thus to synergize with the anti-tumor immunity. The advent of new efficient immunotherapeutic agents, such as immune checkpoint inhibitors (ICI), in multiple tumor types sheds new light on the opportunity of combining RT and ICI. Here, we will describe the biological and radiobiological rationale of the RT-induced ICD. We will then focus on the interest to combine RT and ICI, from bench to bedside, and summarize the clinical data existing with this combination. Finally, RT technical adaptations to optimize the ICD induction will be discussed.


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