Wild-type p53-induced phosphatase 1 down-regulation promotes apoptosis by activating the DNA damage-response pathway in amyotrophic lateral sclerosis

Premature or drug-induced senescence is a major cellular response to chemotherapy in solid tumors. The senescent phenotype develops slowly and is associated with chronic DNA damage response. We found that expression of wild-type p53-induced phosphatase 1 (Wip1) is markedly down-regulated during persistent DNA damage and after drug release during the acquisition of the senescent phenotype in carcinoma cells. We demonstrate that down-regulation of Wip1 is required for maintenance of permanent G2 arrest. In fact, we show that forced expression of Wip1 in premature senescent tumor cells induces inappropriate re-initiation of mitosis, uncontrolled polyploid progression, and cell death by mitotic failure. Most of the effects of Wip1 may be attributed to its ability to dephosphorylate p53 at Ser15 and to inhibit DNA damage response. However, we also uncover a regulatory pathway whereby suppression of p53 Ser15 phosphorylation is associated with enhanced phosphorylation at Ser46, increased p53 protein levels, and induction of Noxa expression. On the whole, our data indicate that down-regulation of Wip1 expression during premature senescence plays a pivotal role in regulating several p53-dependent aspects of the senescent phenotype.

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DNA Damage-Response Pathway in Lymphoma Determines Interactions with Macrophages By Altered PD-L1 Expression and Exosome Formation

Blood ◽

10.1182/blood-2018-99-120264 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 275-275

Author(s):

Daniela Vorholt ◽

Elena Izquierdo-Alvarez ◽

Benedict Sackey ◽

Jan Schmitz ◽

Nadine Nickel ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Research Funding ◽

Therapeutic Response ◽

Wild Type ◽

Lymphoma Cells ◽

Damage Response ◽

Dna Damage Response Pathway ◽

Support Research

Abstract The tumor microenvironment is characterized by multiple interactions of transformed malignant cells with non-transformed stroma or immune cells. Particularly macrophages play a pivotal role in this network determining disease progression and therapeutic response. In previous work we could show that macrophages are an essential mediator of therapeutic response in the synergistic response to the administration of the chemoimmunotherapy. The combination treatment strongly increases tumor clearance by repolarization of tumor-associated macrophages from a suppressive to an activated phenotypic state. Here, se analyzed the functional implications of the DNA damage response pathway for the generation of the ASAP and synergy in chemoimmunotherapy. We attempted to disrupt DNA damage response pathway in lymphoma cells generated from the hMB humanized Double-Hit-Lymphoma model by knock-down of key elements like ATM, DNA-PK or p53. We could prevent the formation of the stimulatory cytokine release effect on macrophage phagocytic capacity. Here, p53 status displays a key regulatory role on macrophage mediated malignant cell depletion. TP53 activation via Nutlin-3A treatment of lymphoma cell enhances ADCP in in p53 wild-type cells, while not displaying enhancement in p53-deficient lymphoma cells. Addressing the treatment in vivo using the hMB model for modeling of Double-Hit Lymphoma bearing mice we could demonstrate diminished ASAP and ADCP for p53-deficient lymphoma treated with cyclophosphamide in vivo. Using primary human CLL patient cells comparing both wild-type and p53-deficient status, the p53-deficient CLL cells failed to induce the stimulatory, cytokine-mediated effect on macrophage phagocytosis in response to combination treatment as seen with the p53 proficient CLL cells. Using a CLL mouse model by treating Eµ-TCL1/p53wt/wt as well as Eµ-TCL1p53-/- mice we could show that low-dose cyclophosphamide treated Eµ-TCL1p53-/- mice failed to induce an antibody mediated stimulatory effect on macrophage phagocytosis capacity as seen with Eµ-TCL1/p53wt/wt mice. A similar effect was seen for primary multiple myeloma cells in response to daratumumab displaying significantly less ADCP of p53-deficient multiple myeloma cells. As for the mechanism of p53-defined interaction within the tumor microenvironment we subjected p53-wild-type and p53-deficient lymphoma cells for proteomic analysis. Here we could identify a significantly deregulated protein expression profile for exosome release in p53 deficient lymphoma cells. Verifying this finding by assessing size and frequency exosomes released by respective cell populations we reveal profound changes induced by p53 loss. Furthermore we could identify up-regulation of PD-L1 in p53-deficient cells. Blocking this checkpoint in the ADCP assay could significantly restore phagocytic capacity of macrophages and overall therapeutic response. In this work, we indicate that p53 functional status determines phagocytic function and therapeutic response to monoclonal antibodies. We can verify this finding in independent models in vitro and in vivo as in primary CLL and myeloma patient cells. We furthermore identify altered exosome profiles and checkpoint inhibitor expression in lymphoma cells as underlying mechanism of macrophage modulation. Finally our ongoing research offers possibility to reveal and tailor new combinatorial treatment approaches for chemo-refractory patients. Disclosures Wendtner: Genetech: Consultancy, Honoraria, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: travel support, Research Funding; Abbvie: Consultancy, Honoraria, Other: travel support, Research Funding; MorphoSys: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; Roche: Consultancy, Honoraria, Other: travel support, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding. Hallek:Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding. Pallasch:Gilead: Research Funding.

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A Commentary on TDP-43 and DNA Damage Response in Amyotrophic Lateral Sclerosis

Journal of Experimental Neuroscience ◽

10.1177/1179069519880166 ◽

2019 ◽

Vol 13 ◽

pp. 117906951988016 ◽

Cited By ~ 1

Author(s):

Joy Mitra ◽

Muralidhar L Hegde

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Amyotrophic Lateral Sclerosis ◽

Dna Damage Response ◽

Motor Neurons ◽

Dsb Repair ◽

Spinal Motor Neurons ◽

Spinal Motor ◽

Damage Response ◽

Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating, motor neuron degenerative disease without any cure. About 95% of the ALS patients feature abnormalities in the RNA/DNA-binding protein, TDP-43, involving its nucleo-cytoplasmic mislocalization in spinal motor neurons. How TDP-43 pathology triggers neuronal apoptosis remains unclear. In a recent study, we reported for the first time that TDP-43 participates in the DNA damage response (DDR) in neurons, and its nuclear clearance in spinal motor neurons caused DNA double-strand break (DSB) repair defects in ALS. We documented that TDP-43 was a key component of the non-homologous end joining (NHEJ) pathway of DSB repair, which is likely the major pathway for repair of DSBs in post-mitotic neurons. We have also uncovered molecular insights into the role of TDP-43 in DSB repair and showed that TDP-43 acts as a scaffold in recruiting the XRCC4/DNA Ligase 4 complex at DSB damage sites and thus regulates a critical rate-limiting function in DSB repair. Significant DSB accumulation in the genomes of TDP-43-depleted, human neural stem cell-derived motor neurons as well as in ALS patient spinal cords with TDP-43 pathology, strongly supported a TDP-43 involvement in genome maintenance and toxicity-induced genome repair defects in ALS. In this commentary, we highlight our findings that have uncovered a link between TDP-43 pathology and impaired DNA repair and suggest potential possibilities for DNA repair-targeted therapies for TDP-43-ALS.

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Wild-type p53-induced phosphatase 1 (Wip1) forestalls cellular premature senescence at physiological oxygen levels by regulating DNA damage response signaling during DNA replication

Cell Cycle ◽

10.4161/cc.27920 ◽

2014 ◽

Vol 13 (6) ◽

pp. 1015-1029 ◽

Cited By ~ 14

Author(s):

Hiroyasu Sakai ◽

Hidetsugu Fujigaki ◽

Sharlyn Mazur ◽

Ettore Appella

Keyword(s):

Dna Damage ◽

Dna Replication ◽

Dna Damage Response ◽

Premature Senescence ◽

Wild Type ◽

Oxygen Levels ◽

Damage Response ◽

Wild Type P53

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The role of DNA damage response in amyotrophic lateral sclerosis

Essays in Biochemistry ◽

10.1042/ebc20200002 ◽

2020 ◽

Vol 64 (5) ◽

pp. 847-861 ◽

Cited By ~ 1

Author(s):

Yu Sun ◽

Annabel J. Curle ◽

Arshad M. Haider ◽

Gabriel Balmus

Keyword(s):

Dna Damage ◽

Amyotrophic Lateral Sclerosis ◽

Genomic Instability ◽

Dna Damage Response ◽

Disease Mechanisms ◽

Age Related ◽

Sporadic Als ◽

Damage Response ◽

Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is a rapidly disabling and fatal neurodegenerative disease. Due to insufficient disease-modifying treatments, there is an unmet and urgent need for elucidating disease mechanisms that occur early and represent common triggers in both familial and sporadic ALS. Emerging evidence suggests that impaired DNA damage response contributes to age-related somatic accumulation of genomic instability and can trigger or accelerate ALS pathological manifestations. In this review, we summarize and discuss recent studies indicating a direct link between DNA damage response and ALS. Further mechanistic understanding of the role genomic instability is playing in ALS disease pathophysiology will be critical for discovering new therapeutic avenues.

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