scholarly journals The Multifunctional Protein p62 and Its Mechanistic Roles in Cancers

2019 ◽  
Vol 19 (6) ◽  
pp. 468-478 ◽  
Author(s):  
Shunbin Ning ◽  
Ling Wang

The multifunctional signaling hub p62 is well recognized as a ubiquitin sensor and a selective autophagy receptor. As a ubiquitin sensor, p62 promotes NFκB activation by facilitating TRAF6 ubiquitination and aggregation. As a selective autophagy receptor, p62 sorts ubiquitinated substrates including p62 itself for lysosome-mediated degradation. p62 plays crucial roles in myriad cellular processes including DNA damage response, aging/senescence, infection and immunity, chronic inflammation, and cancerogenesis, dependent on or independent of autophagy. Targeting p62-mediated autophagy may represent a promising strategy for clinical interventions of different cancers. In this review, we summarize the transcriptional and post-translational regulation of p62, and its mechanistic roles in cancers, with the emphasis on its roles in regulation of DNA damage response and its connection to the cGAS-STING-mediated antitumor immune response, which is promising for cancer vaccine design.

2019 ◽  
Vol 21 (1) ◽  
pp. 55 ◽  
Author(s):  
Vassilis L. Souliotis ◽  
Nikolaos I. Vlachogiannis ◽  
Maria Pappa ◽  
Alexandra Argyriou ◽  
Panagiotis A. Ntouros ◽  
...  

The DNA damage response and repair (DDR/R) network, a sum of hierarchically structured signaling pathways that recognize and repair DNA damage, and the immune response to endogenous and/or exogenous threats, act synergistically to enhance cellular defense. On the other hand, a deregulated interplay between these systems underlines inflammatory diseases including malignancies and chronic systemic autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Patients with these diseases are characterized by aberrant immune response to self-antigens with widespread production of autoantibodies and multiple-tissue injury, as well as by the presence of increased oxidative stress. Recent data demonstrate accumulation of endogenous DNA damage in peripheral blood mononuclear cells from these patients, which is related to (a) augmented DNA damage formation, at least partly due to the induction of oxidative stress, and (b) epigenetically regulated functional abnormalities of fundamental DNA repair mechanisms. Because endogenous DNA damage accumulation has serious consequences for cellular health, including genomic instability and enhancement of an aberrant immune response, these results can be exploited for understanding pathogenesis and progression of systemic autoimmune diseases, as well as for the development of new treatments.


2019 ◽  
Vol 201 (17) ◽  
Author(s):  
Shruti Mishra ◽  
Reema Chaudhary ◽  
Sudhir Singh ◽  
Swathi Kota ◽  
Hari S. Misra

ABSTRACT Guanine quadruplex (G4) DNA/RNA are secondary structures that regulate the various cellular processes in both eukaryotes and bacteria. Deinococcus radiodurans, a Gram-positive bacterium known for its extraordinary radioresistance, shows a genomewide occurrence of putative G4 DNA-forming motifs in its GC-rich genome. N-Methyl mesoporphyrin (NMM), a G4 DNA structure-stabilizing drug, did not affect bacterial growth under normal conditions but inhibited the postirradiation recovery of gamma-irradiated cells. Transcriptome sequencing analysis of cells treated with both radiation and NMM showed repression of gamma radiation-responsive gene expression, which was observed in the absence of NMM. Notably, this effect of NMM on the expression of housekeeping genes involved in other cellular processes was not observed. Stabilization of G4 DNA structures mapped at the upstream of recA and in the encoding region of DR_2199 had negatively affected promoter activity in vivo, DNA synthesis in vitro and protein translation in Escherichia coli host. These results suggested that G4 DNA plays an important role in DNA damage response and in the regulation of expression of the DNA repair proteins required for radioresistance in D. radiodurans. IMPORTANCE Deinococcus radiodurans can recover from extensive DNA damage caused by many genotoxic agents. It lacks LexA/RecA-mediated canonical SOS response. Therefore, the molecular mechanisms underlying the regulation of DNA damage response would be worth investigating in this bacterium. D. radiodurans genome is GC-rich and contains numerous islands of putative guanine quadruplex (G4) DNA structure-forming motifs. Here, we showed that in vivo stabilization of G4 DNA structures can impair DNA damage response processes in D. radiodurans. Essential cellular processes such as transcription, DNA synthesis, and protein translation, which are also an integral part of the double-strand DNA break repair pathway, are affected by the arrest of G4 DNA structure dynamics. Thus, the role of DNA secondary structures in DNA damage response and radioresistance is demonstrated.


2018 ◽  
Vol 5 (1) ◽  
pp. 141-164 ◽  
Author(s):  
Matthew D. Weitzman ◽  
Amélie Fradet-Turcotte

Viral DNA genomes have limited coding capacity and therefore harness cellular factors to facilitate replication of their genomes and generate progeny virions. Studies of viruses and how they interact with cellular processes have historically provided seminal insights into basic biology and disease mechanisms. The replicative life cycles of many DNA viruses have been shown to engage components of the host DNA damage and repair machinery. Viruses have evolved numerous strategies to navigate the cellular DNA damage response. By hijacking and manipulating cellular replication and repair processes, DNA viruses can selectively harness or abrogate distinct components of the cellular machinery to complete their life cycles. Here, we highlight consequences for viral replication and host genome integrity during the dynamic interactions between virus and host.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Wang ◽  
Jianshuang Li ◽  
Junyang Tan ◽  
Miaomiao Wang ◽  
Jing Yang ◽  
...  

AbstractEndonuclease G (ENDOG), a mitochondrial nuclease, is known to participate in many cellular processes, including apoptosis and paternal mitochondrial elimination, while its role in autophagy remains unclear. Here, we report that ENDOG released from mitochondria promotes autophagy during starvation, which we find to be evolutionally conserved across species by performing experiments in human cell lines, mice, Drosophila and C. elegans. Under starvation, Glycogen synthase kinase 3 beta-mediated phosphorylation of ENDOG at Thr-128 and Ser-288 enhances its interaction with 14-3-3γ, which leads to the release of Tuberin (TSC2) and Phosphatidylinositol 3-kinase catalytic subunit type 3 (Vps34) from 14-3-3γ, followed by mTOR pathway suppression and autophagy initiation. Alternatively, ENDOG activates DNA damage response and triggers autophagy through its endonuclease activity. Our results demonstrate that ENDOG is a crucial regulator of autophagy, manifested by phosphorylation-mediated interaction with 14-3-3γ, and its endonuclease activity-mediated DNA damage response.


2003 ◽  
Vol 23 (12) ◽  
pp. 4247-4256 ◽  
Author(s):  
Zhi-Xiang Xu ◽  
Anna Timanova-Atanasova ◽  
Rui-Xun Zhao ◽  
Kun-Sang Chang

ABSTRACT The PML tumor suppressor gene is consistently disrupted by t(15;17) in patients with acute promyelocytic leukemia. Promyelocytic leukemia protein (PML) is a multifunctional protein that plays essential roles in cell growth regulation, apoptosis, transcriptional regulation, and genome stability. Our study here shows that PML colocalizes and associates in vivo with the DNA damage response protein TopBP1 in response to ionizing radiation (IR). Both PML and TopBP1 colocalized with the IR-induced bromodeoxyuridine single-stranded DNA foci. PML and TopBP1 also colocalized with Rad50, Brca1, ATM, Rad9, and BLM. IR and interferon (IFN) coinduce the expression levels of both TopBP1 and PML. In PML-deficient NB4 cells, TopBP1 was unable to form IR-induced foci. All-trans-retinoic acid induced reorganization of the PML nuclear body (NB) and reappearance of the IR-induced TopBP1 foci. Inhibition of PML expression by siRNA is associated with a significant decreased in TopBP1 expression. Furthermore, PML-deficient cells express a low level of TopBP1, and its expression cannot be induced by IR or IFN. Adenovirus-mediated overexpression of PML in PML−/− mouse embryo fibroblasts substantially increased TopBP1 expression, which colocalized with the PML NBs. These studies demonstrated a mechanism of PML-dependent expression of TopBP1. PML overexpression induced TopBP1 protein but not the mRNA expression. Pulse-chase labeling analysis demonstrated that PML overexpression stabilized the TopBP1 protein, suggesting that PML plays a role in regulating the stability of TopBP1 in response to IR. Together, our findings demonstrate that PML regulates TopBP1 functions by association and stabilization of the protein in response to IR-induced DNA damage.


2017 ◽  
Author(s):  
Alexander P. Glaser ◽  
Damiano Fantini ◽  
Kalen J. Rimar ◽  
Joshua J. Meeks

AbstractBackgroundThe APOBEC family of enzymes is responsible for a mutation signature characterized by a TCW>T/G mutation. APOBEC-mediated mutagenesis is implicated in a wide variety of tumors, including bladder cancer. In this study, we explore the APOBEC mutational signature in bladder cancer and the relationship with specific mutations, molecular subtype, gene expression, and survival. We hypothesized that tumors with high levels of APOBEC-mediated mutagenesis would be enriched for mutations in DNA damage response genes and associated with higher expression of genes related to activation of the immune system.MethodsGene expression (n=408) and mutational (n=395) data from the Cancer Genome Atlas (TCGA) bladder urothelial carcinoma provisional dataset was utilized for analysis. Tumors were split into “APOBEC-high” and “APOBEC-low” tumors based on APOBEC enrichment score. Analysis was performed with R.FindingsPatients with APOBEC-high tumors have better overall survival compared to those with APOBEC-low tumors (38.2 vs 18.5 months, p=0.005). Tumors enriched for APOBEC mutagenesis are more likely to have mutations in DNA damage response genes (TP53, ATR, BRCA2), and chromatin regulatory genes (MLL, MLL3), while APOBEC-low tumors are more likely to have mutations inFGFR3andKRAS. APOBEC3AandAPOBEC3Bexpression correlates with total mutational burden, regardless of bladder tumor molecular subtype. APOBEC mutagenesis and enrichment is associated with increased expression of immune-related genes, including interferon signaling.InterpretationTumors enriched for APOBEC mutagenesis are more likely to have mutations in DNA damage response genes and chromatin regulatory genes, potentially providing more single-strand DNA substrate forAPOBEC3AandAPOBEC3B, leading to a hypermutational phenotype and the subsequent immune response.HighlightsABPOEC enzymes, particularlyAPOBEC3AandAPOBEC3B, are responsible for the predominant pattern of mutagenesis in bladder cancerTumors enriched for APOBEC-mediated mutagenesis are more likely to have mutations in DNA damage response genes and chromatin regulatory genes, while tumors not enriched for APOBEC-mediated mutagenesis are more likely to have mutations inKRASandFGFR3APOBEC enrichment is associated with upregulation of genes involved in the immune response


Author(s):  
Stina George Fernandes ◽  
Prachi Shah ◽  
Ekta Khattar

: DNA integrity is continuously challenged by intrinsic cellular processes and environmental agents. To overcome this genomic damage, cells have developed multiple signaling pathways collectively named as DNA damage response (DDR) and composed of three components: (i) sensor proteins, which detect DNA damage, (ii) mediators that relay the signal downstream and recruit the repair machinery, and (iii) the repair proteins, which restore the damaged DNA. A flawed DDR and failure to repair the damage lead to the accumulation of genetic lesions and increased genomic instability, which is recognized as a hallmark of cancer. Cancer cells tend to harbor increased mutations in DDR genes and often have fewer DDR pathways than normal cells. This makes cancer cells more dependent on particular DDR pathways and thus become more susceptible to compounds inhibiting those pathways compared to normal cells, which have all the DDR pathways intact. Understanding the roles of different DDR proteins in the DNA damage response and repair pathways and identification of their structures have paved the way for the development of their inhibitors as targeted cancer therapy. In this review, we describe the major participants of various DDR pathways, their significance in carcinogenesis, and focus on the inhibitors developed against several key DDR proteins.


2018 ◽  
Vol 10 ◽  
pp. 175883591878665 ◽  
Author(s):  
Anna Minchom ◽  
Caterina Aversa ◽  
Juanita Lopez

Maintenance of genomic stability is a critical determinant of cell survival and relies on the coordinated action of the DNA damage response (DDR), which orchestrates a network of cellular processes, including DNA replication, DNA repair and cell-cycle progression. In cancer, the critical balance between the loss of genomic stability in malignant cells and the DDR provides exciting therapeutic opportunities. Drugs targeting DDR pathways taking advantage of clinical synthetic lethality have already shown therapeutic benefit – for example, the PARP inhibitor olaparib has shown benefit in BRCA-mutant ovarian and breast cancer. Olaparib has also shown benefit in metastatic prostate cancer in DDR-defective patients, expanding the potential biomarker of response beyond BRCA. Other agents and combinations aiming to block the DDR while pushing damaged DNA through the cell cycle, including PARP, ATR, ATM, CHK and DNA-PK inhibitors, are in development. Emerging work is also uncovering how the DDR interacts intimately with the host immune response, including by activating the innate immune response, further suggesting that clinical applications together with immunotherapy may be beneficial. Here, we review recent considerations related to the DDR from a clinical standpoint, providing a framework to address future directions and clinical opportunities.


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