A dual role for UVRAG in maintaining chromosomal stability independent of autophagy

Emerging dimensions of autophagy in melanoma

Macroautophagy/autophagy has previously been regarded as simply a way for cells to deal with nutrient emergency. But explosive work in the last 15 years has given increasingly new knowledge to our understanding of this process. Many of the functions of autophagy that are unveiled from recent studies, however, cannot be reconciled with this conventional view of cell survival but, instead, point to autophagy being integrally involved at a deeper level of cell biology, playing a critical role in maintaining homeostasis and promoting an integrated stress/immune response. The new appreciation of the role of autophagy in the evolutionary trajectory of cancer and cancer interaction with the immune system provides a mechanistic framework for understanding the clinical benefits of autophagy-based therapies. Here, we examine current knowledge of the mechanisms and functions of autophagy in highly plastic and aggressive melanoma as a model disease of human malignancy, while highlighting emerging dimensions indicating that autophagy is at play beyond its classical face.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ATF4: activating transcription factor 4; ATG: autophagy related; BRAF: B-Raf proto-oncogene, serine/threonine kinase; CAFs: cancer-associated fibroblasts; CCL5: C-C motif chemokine ligand 5; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; CTLA4: cytotoxic T-lymphocyte associated protein 4; CTL: cytotoxic T lymphocyte; DAMPs: danger/damage-associated molecular patterns; EGFR: epidermal growth factor receptor; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; FITM2: fat storage inducing transmembrane protein 2; HCQ: hydroxychloroquine; ICB: immune checkpoint blockade; ICD: immunogenic cell death; LDH: lactate dehydrogenase; MAPK: mitogen-activated protein kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; NDP52: nuclear dot protein 52; NFKB/NF-κ B: nuclear factor kappa B; NBR1: the neighbor of BRCA1; NK: natural killer; NRF1: nuclear respiratory factor 1; NSCLC: non-small-cell lung cancer; OPTN: optineurin; PDAC: pancreatic ductal adenocarcinoma; PDCD1/PD-1: programmed cell death 1; PPT1: palmitoyl-protein thioesterase 1; PTEN: phosphatase and tensin homolog; PTK2/FAK1: protein tyrosine kinase 2; RAS: rat sarcoma; SQSTM1/p62: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGFB/TGF-β: transforming growth factor beta; TMB: tumor mutational burden; TME: tumor microenvironment; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated.

Beyond self‑eating: Emerging autophagy‑independent functions for the autophagy molecules in cancer (Review)

Autophagy is a conserved catabolic process that controls organelle quality, removes misfolded or abnormally aggregated proteins and is part of the defense mechanisms against intracellular pathogens. Autophagy contributes to the suppression of tumor initiation by promoting genome stability, cellular integrity, redox balance and proteostasis. On the other hand, once a tumor is established, autophagy can support cancer cell survival and promote epithelial‑to‑mesenchymal transition. A growing number of molecules involved in autophagy have been identified. In addition to their key canonical activity, several of these molecules, such as ATG5, ATG12 and Beclin‑1, also exert autophagy‑independent functions in a variety of biological processes. The present review aimed to summarize autophagy‑independent functions of molecules of the autophagy machinery and how the activity of these molecules can influence signaling pathways that are deregulated in cancer progression.

NLRX1 Inhibits LPS-Induced Microglial Death via Inducing p62-Dependent HO-1 Expression, Inhibiting MLKL and Activating PARP-1

The activation of microglia and the production of cytokines are key factors contributing to progressive neurodegeneration. Despite the well-recognized neuronal programmed cell death regulated by microglial activation, the death of microglia themselves is less investigated. Nucleotide-binding oligomerization domain, leucine-rich repeat-containing X1 (NLRX1) functions as a scaffolding protein and is involved in various central nervous system diseases. In this study, we used the SM826 microglial cells to understand the role of NLRX1 in lipopolysaccharide (LPS)-induced cell death. We found LPS-induced cell death is blocked by necrostatin-1 and zVAD. Meanwhile, LPS can activate poly (ADP-ribose) polymerase-1 (PARP-1) to reduce DNA damage and induce heme oxygenase (HO)-1 expression to counteract cell death. NLRX1 silencing and PARP-1 inhibition by olaparib enhance LPS-induced SM826 microglial cell death in an additive manner. Less PARylation and higher DNA damage are observed in NLRX1-silencing cells. Moreover, LPS-induced HO-1 gene and protein expression through the p62-Keap1-Nrf2 axis are attenuated by NLRX1 silencing. In addition, the Nrf2-mediated positive feedback regulation of p62 is accordingly reduced by NLRX1 silencing. Of note, NLRX1 silencing does not affect LPS-induced cellular reactive oxygen species (ROS) production but increases mixed lineage kinase domain-like pseudokinase (MLKL) activation and cell necroptosis. In addition, NLRX1 silencing blocks bafilomycin A1-induced PARP-1 activation. Taken together, for the first time, we demonstrate the role of NLRX1 in protecting microglia from LPS-induced cell death. The underlying protective mechanisms of NLRX1 include upregulating LPS-induced HO-1 expression via Nrf2-dependent p62 expression and downstream Keap1-Nrf2 axis, mediating PARP-1 activation for DNA repair via ROS- and autophagy-independent pathway, and reducing MLKL activation.

The nonautophagic functions of autophagy-related proteins

ABBREVIATIONS

ATG: autophagy related; BECN1: beclin 1; cAMP: cyclic adenosine monophosphate; dsDNA: double-stranded DNA; EMT: epithelial-mesenchymal transition; IFN: interferon; ISCs: intestinal stem cells; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK/JNK: mitogen-activated protein kinase/c-Jun N-terminal kinases; MTOR: mechanistic target of rapamycin kinase; STING1: stimulator of interferon response cGAMP interactor 1; UVRAG: UV radiation resistance associated; VPS: vacuolar protein sorting.

UVRAG cooperates with cargo receptors to assemble the ER-phagy site

ER-phagy is a selective autophagy process that targets specific regions of the endoplasmic reticulum (ER) for removal via lysosomal degradation. During cellular stress induced by starvation, cargo receptors concentrate at distinct ER-phagy sites (ERPHS) to recruit core autophagy proteins and initiate ER-phagy. However, the molecular mechanism responsible for ERPHS formation remains unclear. In our study, we discovered that the autophagy regulator UV radiation Resistance-Associated Gene (UVRAG) plays a crucial role in orchestrating the assembly of ERPHS. Upon starvation, UVRAG localizes to ERPHS and interacts with specific ER-phagy cargo receptors, such as FAM134B, ATL3, and RTN3L. UVRAG regulates the oligomerization of cargo receptors and facilitates the recruitment of Atg8 family proteins. Consequently, UVRAG promotes efficient ERPHS assembly and turnover of both ER sheets and tubules. Importantly, UVRAG-mediated ER-phagy contributes to the clearance of pathogenic proinsulin aggregates. Remarkably, the involvement of UVRAG in ER-phagy initiation is independent of its canonical function as a subunit of class III phosphatidylinositol 3-kinase complex II.

UVRAG Promotes Tumor Progression through Regulating SP1 in Colorectal Cancer

Colorectal cancer (CRC) is the third most common type of cancer. The ultraviolet radiation resistance-associated gene (UVRAG) plays a role in autophagy and has been implicated in tumor progression and prognosis. However, the role of UVRAG expression in CRC has remained elusive. In this study, the prognosis was analyzed via immunohistochemistry, and the genetic changes were compared between the high UVRAG expression group and the low UVRAG expression group using RNA sequencing (RNA-seq) and single-cell RNA-seq (scRNA-seq) data, and genetic changes were then identified by in vitro experiments. It was found that UVRAG could enhance tumor migration, drug resistance, and CC motif chemokine ligand 2 (CCL2) expression to recruit macrophages by upregulating SP1 expression, resulting in poor prognosis of CRC patients. In addition, UVRAG could upregulate the expression of programmed death-ligand 1 (PD-L1). In summary, the relationship between UVRAG expression and the prognosis of CRC patients as well as the potential mechanisms in CRC were explored, providing evidence for the treatment of CRC.

Autophagy Paradox: Strategizing Treatment Modality in Melanoma

OPINION STATEMENT

The primordial autophagy process, originally identified as a starvation response in baker's yeast, has since been shown to have a wide spectrum of functions other than survival. In many cases, it is accepted that autophagy operates as a key tumor suppressor mechanism that protects cells from adverse environmental cues by enforcing homeostasis and maintaining the functional and structural integrity of organelles. Paradoxically, heightened states of autophagy are also seen in some cancers, leading to the prevailing view that the pro-survival aspect of autophagy might be hijacked by some tumors to promote their fitness and pathogenesis. Notably, recent studies have revealed a broad range of cell-autonomous autophagy in reshaping tumor microenvironment and maintaining lineage integrity and immune homeostasis, calling for a renewed understanding of autophagy beyond its classical roles in cell survival. Here, we evaluate the increasing body of literature that argues the "double-edged" consequences of autophagy manipulation in cancer therapy, with a particular focus on highly plastic and mutagenic melanoma. We also discuss the caveats that must be considered when evaluating whether autophagy blockade is the effector mechanism of some anti-cancer therapy particularly associated with lysosomotropic agents. If autophagy proteins are to be properly exploited as targets for anticancer drugs, their diverse and complex roles should also be considered.

Nanotherapeutics in autophagy: a paradigm shift in cancer treatment

Autophagy is a catabolic process in which an organism responds to its nutrient or metabolic emergencies. It involves the degradation of cytoplasmic proteins and organelles by forming double-membrane vesicles called "autophagosomes." They sequester cargoes, leading them to degradation in the lysosomes. Although autophagy acts as a protective mechanism for maintaining homeostasis through cellular recycling, it is ostensibly a cause of certain cancers, but a cure for others. In other words, insufficient autophagy, due to genetic or cellular dysfunctions, can lead to tumorigenesis. However, many autophagy modulators are developed for cancer therapy. Diverse nanoparticles have been documented to induce autophagy. Also, the highly stable nanoparticles show blockage to autophagic flux. In this review, we revealed a general mechanism by which autophagy can be induced or blocked via nanoparticles as well as several studies recently performed to prove the stated fact. In addition, we have also elucidated the paradoxical roles of autophagy in cancer and how their differential role at different stages of various cancers can affect its treatment outcomes. And finally, we summarize the breakthroughs in cancer disease treatments by using metallic, polymeric, and liposomal nanoparticles as potent autophagy modulators.

Autophagy plays an essential role in ultraviolet radiation-driven skin photoaging

Photoaging is characterized by a chronic inflammatory response to UV light. One of the most prominent features of cutaneous photoaging is wrinkling, which is due primarily to a loss of collagen fibers and deposits of abnormal degenerative elastotic material within the dermis (actinic elastosis). These changes are thought to be mediated by inflammation, with subsequent upregulation of extracellular matrix-degrading proteases and down-regulation of collagen synthesis. Autophagy is a vital homeostatic cellular process of either clearing surplus or damaged cell components notably lipids and proteins or recycling the content of the cells’ cytoplasm to promote cell survival and adaptive responses during starvation and other oxidative and/or genotoxic stress conditions. Autophagy may also become a means of supplying nutrients to maintain a high cellular proliferation rate when needed. It has been suggested that loss of autophagy leads to both photodamage and the initiation of photoaging in UV exposed skin. Moreover, UV radiation of sunlight is capable of regulating a number of autophagy-linked genes. This review will focus on the protective effect of autophagy in the skin cells damaged by UV radiation. We hope to draw attention to the significance of autophagy regulation in the prevention and treatment of skin photoaging.

Nrf2 Pathway and Autophagy Crosstalk: New Insights into Therapeutic Strategies for Ischemic Cerebral Vascular Diseases

Cerebrovascular disease is highly prevalent and has a complex etiology and variable pathophysiological activities. It thus poses a serious threat to human life and health. Currently, pathophysiological research on cerebrovascular diseases is gradually improving, and oxidative stress and autophagy have been identified as important pathophysiological activities that are gradually attracting increasing attention. Many studies have found some effects of oxidative stress and autophagy on cerebrovascular diseases, and studies on the crosstalk between the two in cerebrovascular diseases have made modest progress. However, further, more detailed studies are needed to determine the specific mechanisms. This review discusses nuclear factor erythroid 2-related factor 2 (Nrf2) molecules, which are closely associated with oxidative stress and autophagy, and the crosstalk between them, with the aim of providing clues for studying the two important pathophysiological changes and their crosstalk in cerebrovascular diseases as well as exploring new target treatments.

Emerging roles of mitotic autophagy

Lysosomes exert pleiotropic functions to maintain cellular homeostasis and degrade autophagy cargo. Despite the great advances that have boosted our understanding of autophagy and lysosomes in both physiology and pathology, their function in mitosis is still controversial. During mitosis, most organelles are reshaped or repurposed to allow the correct distribution of chromosomes. Mitotic entry is accompanied by a reduction in sites of autophagy initiation, supporting the idea of an inhibition of autophagy to protect the genetic material against harmful degradation. However, there is accumulating evidence revealing the requirement of selective autophagy and functional lysosomes for a faithful chromosome segregation. Degradation is the most-studied lysosomal activity, but recently described alternative functions that operate in mitosis highlight the lysosomes as guardians of mitotic progression. Because the involvement of autophagy in mitosis remains controversial, it is important to consider the specific contribution of signalling cascades, the functions of autophagic proteins and the multiple roles of lysosomes, as three entangled, but independent, factors controlling genomic stability. In this Review, we discuss the latest advances in this area and highlight the therapeutic potential of targeting autophagy for drug development.

A novel ATG5 interaction with Ku70 potentiates DNA repair upon genotoxic stress

The maintenance of cellular homeostasis in living organisms requires a balance between anabolic and catabolic reactions. Macroautophagy (autophagy herein) is determined as one of the major catabolic reactions. Autophagy is an evolutionarily conserved stress response pathway that is activated by various insults including DNA damage. All sorts of damage to DNA potentially cause loss of genetic information and trigger genomic instability. Most of these lesions are repaired by the activation of DNA damage response following DNA repair mechanisms. Here we describe, a novel protein complex containing the autophagy protein ATG5 and the non-homologous end-joining repair system proteins. We discovered for the first time that ATG5 interacted with both Ku80 (XRCC5) and Ku70 (XRCC6). This novel interaction is facilitated mainly via Ku70. Our results suggest that this interaction is dynamic and enhanced upon genotoxic stresses. Strikingly, we identified that ATG5-Ku70 interaction is necessary for DNA repair and effective recovery from genotoxic stress. Therefore, our results are demonstrating a novel, direct, dynamic, and functional interaction between ATG5 and Ku70 proteins that plays a crucial role in DNA repair under genotoxic stress conditions.

Preliminary screening and correlation analysis for lncRNAs related to radiosensitivity in melanoma cells by inhibiting glycolysis

OBJECTIVES

To screen the expression profiles of lncRNA and mRNA related to the radiosensitivity of melanoma cells by inhibiting glycolysis through microarray technology.

METHODS

WM35 melanoma cells were treated with different concentrations (1.25, 2.50, 5.00, 10.00 mmol/L) of 2-deoxy-D-glucose (2-DG) and different doses (0, 2, 4, 6, 8 Gy) of X-ray irradiation. MTT assay was used to detect the proliferation ability of NC-0 Gy group (negative control group), NC-4 Gy group (only 4 Gy X-ray irradiation), 2-DG group (only 2.50 mmol/L DG treatment), and 2-DG-4 Gy group (2.50 mmol/L 2-DG treatment, 4 Gy X-ray irradiation). Microarray chip was used to detect the changes in the expression profiles of lncRNA and mRNA in the NC-4 Gy group and the 2-DG-4 Gy group. Real-time RT-PCR was used to quantitatively detect the top 5 upregulated and the top 5 downregulated expression lncRNA. CNC analysis was used to predict potential target genes for the 10 most significantly expressed lncRNAs, after which the co-expression network of lncRNA and co-regulated mRNA were constructed. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to predict the functional distribution of differentially expressed lncRNA. Real-time RT-PCR was used to quantitatively detect the top 5 upregulated and the top 5 downregulated expression lncRNAs.

RESULTS

After 48 and 96 h, the cell proliferation of WM35 treated with 2-DG was significantly inhibited in a dose-dependent manner (all P<0.05). The cell proliferation of WM35 was inhibited by a high dose of X-ray irradiation, resulting in the death of mass cells. The cell proliferation activity of WM35 after 4 Gy X-ray irradiation descended 61% compared to the negative control group. Microarray analysis showed that there were 1 206 lncRNAs and 543 differentially expressed mRNAs between the NC-4 Gy group and the 2-DG-4 Gy group, while real-time RT-PCR showed basically consistent changes in lncRNA and mRNA microarray. Further CNC analysis showed that these 10 lncRNAs had a positive or negative correlation with 333 target genes. GO analysis was mainly concentrated in DNA binding, DNA damage repair, cell cycle arrest, and oxidative stress, while KEGG pathway analysis showed the 10 lncRNAs were related to radiosensitivity.

CONCLUSIONS

Microarray chip screens the expression profiles of differentially expressed lncRNA related to the radiosensitivity of melanoma cells via inhibiting glycolysis, and lncRNA RPL34-AS1 might be a potential biological target for melanoma radiotherapy.

Crosstalk between autophagy and DNA repair systems

Autophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity. Hence, in collaboration with DNA damage repair and response mechanisms, autophagy contributes to the maintenance of genomic stability and integrity. Yet, connections and interactions between these two systems are not fully understood. In this review article, current status of the associations and crosstalk between autophagy and DNA repair systems is documented and discussed.

Centrosome-phagy: implications for human diseases

Autophagy is a prominent mechanism to preserve homeostasis and the response to intracellular or extracellular stress. Autophagic degradation can be selectively targeted to dysfunctional subcellular compartments. Centrosome homeostasis is pivotal for healthy proliferating cells, but centrosome aberration is a hallmark of diverse human disorders. Recently, a process called centrosome-phagy has been identified. The process involves a panel of centrosomal proteins and centrosome-related pathways that mediate the specific degradation of centrosomal components via the autophagic machinery. Although autophagy normally mediates centrosome homeostasis, autophagy defects facilitate ageing and multiple human diseases, such as ciliopathies and cancer, which benefit from centrosome aberration. Here, we discuss the molecular systems that trigger centrosome-phagy and its role in human disorders.

Suppressing UVRAG Induces Radiosensitivity by Triggering Lysosomal Membrane Permeabilization in Hypopharyngeal Squamous Cell Carcinoma

Introduction

Radiotherapy is one of the most important methods in the treatment of patients with hypopharyngeal squamous cell carcinoma (HSCC). However, radioresistance will be developed after repeated irradiation. Among many key factors contributing to radioresistance, enhanced autophagy is recognized as one of the most important. The ultraviolent irradiation resistance-associated gene (UVRAG) is reported to be a crucial gene involved in the process of autophagy. Here, we test whether UVRAG has effect on the radioresistance of HSCC.

Methods

HSCC cell line Fadu cells were treated with irradiation to test levels of autophagy. Tumor tissues from primary and recurrent HSCC patients were tested by immunohistochemistry. Then, we knocked down UVRAG to test its role in cell growth and the malignant behaviors. Response of cells to treatment was examined using LDH release assay, immunofluorescence, Western blot analysis and colony formation.

Results

We found that irradiation induced autophagy in Fadu cells. Immunohistochemistry of primary and irradiated HSCC tumor tissues showed that UVRAG was upregulated after irradiation treatment. Inhibiting UVRAG with siRNA interfered cell growth, cell cycle, malignant behaviors and autophagic flux in Fadu cells. Knocking down UVRAG increased DNA damage and cell death induced by irradiation. Finally, we found that inhibiting UVRAG induced lysosomal membrane permeabilization, which contributed to radiosensitization of Fadu cells.

Conclusion

Our findings supported the oncogenic properties of UVRAG in HSCC and inhibiting UVRAG increased radiosensitivity in HSCC by triggering lysosomal membrane permeabilization. Therefore, UVRAG might be a promising target in the treatment of HSCC.

Integrating DNA damage response and autophagy signalling axis in ultraviolet-B induced skin photo-damage: a positive association in protecting cells against genotoxic stress

The skin acts as both physical as well as an immunological barrier against hazardous agents from the outside environment and protects the internal organs against damage. Skin ageing is a dynamic process caused by the influence of various external factors, including damage from ultraviolet (UV-B) radiation, which is known as photo-ageing, and due to internal chronological mechanisms. A normal ageing process requires several orchestrated defense mechanisms to diverse types of stress responses, the concomitant renewal of cellular characteristics, and the homeostasis of different cell types that directly or indirectly protect the integrity of skin. Cumulative oxidative and endoplasmic reticulum (ER) stress responses and their adverse impact on biological systems in the skin are a common mechanism of the ageing process, negatively impacting DNA by causing mutations that lead to many physiological, functional, and aesthetic changes in the skin, culminating in the development of many diseases, including photo-damage and photo-carcinogenesis. Exposure of the skin to ultraviolet-(B) elicits the activation of signal transduction pathways, including DNA damage response, autophagy, and checkpoint signal adaptations associated with clearing radiation-induced DNA damage. Recent experimental reports suggest that autophagy is involved in maintaining skin homeostasis upon encountering different stresses, notably genotoxic stress. It has also been revealed that autophagy positively regulates the recognition of DNA damage by nucleotide excision repair and that skin ageing is associated with defects in the autophagy process. Moreover, autophagy is constitutively active in the skin epithelium, imparting protection to skin cells against a diverse range of outside insults, thus increasing resistance to environmental stressors. It has also been found that the stress-induced suppression of the autophagy response in experimental settings leads to enhanced apoptosis during photo-ageing upon UV-B exposure and that the maintenance of homeostasis depends on cellular autophagy levels. More recent reports in this domain claim that relieving the oxidative-stress-mediated induction of the ER stress response upon UV-B irradiation protects skin cells from photo-damage effects. The integration of autophagy and the DNA damage response under genotoxic stress is being considered as a meaningful partnership for finding novel molecular targets and devising suitable therapeutic strategies against photo-ageing disorders. Here, we summarize and review the current understanding of the mechanisms governing the intricate interplay between autophagy and the DNA damage response and its regulation by UV-B, the roles of autophagy in regulating the cellular response to UV-B-induced photodamage, and the implications of the modulation of autophagy as a meaningful partnership in the treatment and prevention of photoaging disorders.

Autophagy-Related Beclin 1 and Head and Neck Cancers

Beclin 1, a positive regulator of autophagy, behaves as a double-edged sword in tumorigenesis. Beclin 1 contributes to tumor suppression by removing defective or damaged organelles and other cellular components; however, its activity can also stimulate cancer initiation and progression. In head and neck cancer, Beclin 1 overexpression promotes autophagy, which limits DNA damage and chromosomal instability and increases necrosis and inflammation by impacting apoptotic and autophagic pathways. This paper reviews the relationship between Beclin 1, carcinogenesis and head and neck cancer prognosis.

Reduced-Beclin1-Expressing Mice Infected with Zika-R103451 and Viral-Associated Pathology during Pregnancy

Here, we used a mouse model with defective autophagy to further decipher the role of Beclin1 in the infection and disease of Zika virus (ZIKV)-R103451. Hemizygous (Becn1^+/−) and wild-type (Becn1^+/+) pregnant mice were transiently immunocompromised using the anti-interferon alpha/beta receptor subunit 1 monoclonal antibody MAR1-5A3. Despite a low mortality rate among the infected dams, 25% of Becn1^+/− offspring were smaller in size and had smaller, underdeveloped brains. This phenotype became apparent after 2-to 3-weeks post-birth. Furthermore, the smaller-sized pups showed a decrease in the mRNA expression levels of insulin-like growth factor (IGF)-1 and the expression levels of several microcephaly associated genes, when compared to their typical-sized siblings. Neuronal loss was also noticeable in brain tissues that were removed postmortem. Further analysis with murine mixed glia, derived from ZIKV-infected Becn1^+/− and Becn1^+/+ pups, showed greater infectivity in glia derived from the Becn1^+/− genotype, along with a significant increase in pro-inflammatory molecules. In the present study, we identified a link by which defective autophagy is causally related to increased inflammatory molecules, reduced growth factor, decreased expression of microcephaly-associated genes, and increased neuronal loss. Specifically, we showed that a reduced expression of Beclin1 aggravated the consequences of ZIKV infection on brain development and qualifies Becn1 as a susceptibility gene of ZIKV congenital syndrome.

Autophagy-Independent Functions of the Autophagy Machinery

Macroautophagy (herein referred to as autophagy) is an evolutionary ancient mechanism that culminates with the lysosomal degradation of superfluous or potentially dangerous cytosolic entities. Over the past 2 decades, the molecular mechanisms underlying several variants of autophagy have been characterized in detail. Accumulating evidence suggests that most, if not all, components of the molecular machinery for autophagy also mediate autophagy-independent functions. Here, we discuss emerging data on the non-autophagic functions of autophagy-relevant proteins.

How autophagy is tied to inflammation and cancer

It is not completely understood how autophagy is tied to inflammation and age-related cancer predisposition. Here, we used a mouse model with inducible expression of a cancer-derived frameshift mutation in UV radiation resistance associated (UVRAG) to demonstrate that intervention with autophagy suppressor could exacerbate inflammation and promote age-related spontaneous cancers.

A truncating mutation in the autophagy gene UVRAG drives inflammation and tumorigenesis in mice

Aberrant autophagy is a major risk factor for inflammatory diseases and cancer. However, the genetic basis and underlying mechanisms are less established. UVRAG is a tumor suppressor candidate involved in autophagy, which is truncated in cancers by a frameshift (FS) mutation and expressed as a shortened UVRAGFS. To investigate the role of UVRAGFS in vivo, we generated mutant mice that inducibly express UVRAGFS (iUVRAGFS). These mice are normal in basal autophagy but deficient in starvation- and LPS-induced autophagy by disruption of the UVRAG-autophagy complex. iUVRAGFS mice display increased inflammatory response in sepsis, intestinal colitis, and colitis-associated cancer development through NLRP3-inflammasome hyperactivation. Moreover, iUVRAGFS mice show enhanced spontaneous tumorigenesis related to age-related autophagy suppression, resultant β-catenin stabilization, and centrosome amplification. Thus, UVRAG is a crucial autophagy regulator in vivo, and autophagy promotion may help prevent/treat inflammatory disease and cancer in susceptible individuals.

Nickel Carcinogenesis Mechanism: DNA Damage

Nickel (Ni) is known to be a major carcinogenic heavy metal. Occupational and environmental exposure to Ni has been implicated in human lung and nasal cancers. Currently, the molecular mechanisms of Ni carcinogenicity remain unclear, but studies have shown that Ni-caused DNA damage is an important carcinogenic mechanism. Therefore, we conducted a literature search of DNA damage associated with Ni exposure and summarized known Ni-caused DNA damage effects. In vitro and vivo studies demonstrated that Ni can induce DNA damage through direct DNA binding and reactive oxygen species (ROS) stimulation. Ni can also repress the DNA damage repair systems, including direct reversal, nucleotide repair (NER), base excision repair (BER), mismatch repair (MMR), homologous-recombination repair (HR), and nonhomologous end-joining (NHEJ) repair pathways. The repression of DNA repair is through direct enzyme inhibition and the downregulation of DNA repair molecule expression. Up to now, the exact mechanisms of DNA damage caused by Ni and Ni compounds remain unclear. Revealing the mechanisms of DNA damage from Ni exposure may contribute to the development of preventive strategies in Ni carcinogenicity.

Destabilization of the MiniChromosome Maintenance (MCM) complex modulates the cellular response to DNA double strand breaks

DNA replication during S phase involves thousands of replication forks that must be coordinated to ensure that every DNA section is replicated only once. The minichromosome maintenance proteins, MCM2 to MCM7, form a heteromeric DNA helicase required for both the initiation and elongation of DNA replication. Although only two DNA helicase activities are necessary to establish a bidirectional replication fork from each replication origin, a large excess of MCM complexes is amassed and distributed along the chromatin. The function of the additional MCM complexes is not well understood, as most are displaced from the DNA during the S-phase, apparently without playing an active role in DNA replication. DNA damage response (DDR) kinases activated by stalled forks prevent the replication machinery from being activated, indicating a tight relationship between DDR and DNA replication. To investigate the role of MCM proteins in the cellular response to DNA damage, we used shRNA targeting MCM2 or MCM3 to determine the impact of a reduction in MCM complex. The alteration of MCM proteins induced a change in the activation of key factors of the DDR in response to Etoposide treatment. Etoposide-induced DNA damage affected the phosphorylation of γ-H2AX, CHK1 and CHK2 without affecting cell viability. Using assays measuring homologous recombination (HR) and non-homologous end-joining (NHEJ), we identified a decrease in both HR and NHEJ associated with a decrease in MCM complex.

Chronic Infections: A Possible Scenario for Autophagy and Senescence Cross-Talk

Multiple tissues and systems in the organism undergo modifications during aging due to an accumulation of damaged proteins, lipids, and genetic material. To counteract this process, the cells are equipped with specific mechanisms, such as autophagy and senescence. Particularly, the immune system undergoes a process called immunosenescence, giving rise to a chronic inflammatory status of the organism, with a decreased ability to counteract antigens. The obvious result of this process is a reduced defence capacity. Currently, there is evidence that some pathogens are able to accelerate the immunosenescence process for their own benefit. Although to date numerous reports show the autophagy–senescence relationship, or the connection between pathogens with autophagy or senescence, the link between the three actors remains unexplored. In this review, we have summarized current knowledge about important issues related to aging, senescence, and autophagy.

The multifaceted role of autophagy in cancer and the microenvironment

Autophagy is a crucial recycling process that is increasingly being recognized as an important factor in cancer initiation, cancer (stem) cell maintenance as well as the development of resistance to cancer therapy in both solid and hematological malignancies. Furthermore, it is being recognized that autophagy also plays a crucial and sometimes opposing role in the complex cancer microenvironment. For instance, autophagy in stromal cells such as fibroblasts contributes to tumorigenesis by generating and supplying nutrients to cancerous cells. Reversely, autophagy in immune cells appears to contribute to tumor‐localized immune responses and among others regulates antigen presentation to and by immune cells. Autophagy also directly regulates T and natural killer cell activity and is required for mounting T‐cell memory responses. Thus, within the tumor microenvironment autophagy has a multifaceted role that, depending on the context, may help drive tumorigenesis or may help to support anticancer immune responses. This multifaceted role should be taken into account when designing autophagy‐based cancer therapeutics. In this review, we provide an overview of the diverse facets of autophagy in cancer cells and nonmalignant cells in the cancer microenvironment. Second, we will attempt to integrate and provide a unified view of how these various aspects can be therapeutically exploited for cancer therapy.

Central role of autophagic UVRAG in melanogenesis and the suntan response

UV-induced cell pigmentation represents an important mechanism against skin cancers. Sun-exposed skin secretes α-MSH, which induces the lineage-specific transcriptional factor MITF and activates melanogenesis in melanocytes. Here, we show that the autophagic tumor suppressor UVRAG plays an integral role in melanogenesis by interaction with the biogenesis of lysosome-related organelles complex 1 (BLOC-1). This interaction is required for BLOC-1 stability and for BLOC-1-mediated cargo sorting and delivery to melanosomes. Absence of UVRAG dispersed BLOC-1 distribution and activity, resulting in impaired melanogenesis in vitro and defective melanocyte development in zebrafish in vivo. Furthermore, our results establish UVRAG as an important effector for melanocytes' response to α-MSH signaling as a direct target of MITF and reveal the molecular basis underlying the association between oncogenic BRAF and compromised UV protection in melanoma.

New Insights Into Beclin-1: Evolution and Pan-Malignancy Inhibitor Activity

Autophagy is a functionally conserved self-degradation process that facilitates the survival of eukaryotic life via the management of cellular bioenergetics and maintenance of the fidelity of genomic DNA. The first known autophagy inducer was Beclin-1. Beclin-1 is expressed in multicellular eukaryotes ranging throughout plants to animals, comprising a nonmonophyllic group, as shown in this report via aggressive BLAST searches. In humans, Beclin-1 is a haploinsuffient tumor suppressor as biallelic deletions have not been observed in patient tumors clinically. Therefore, Beclin-1 fails the Knudson hypothesis, implicating expression of at least one Beclin-1 allele is essential for cancer cell survival. However, Beclin-1 is frequently monoallelically deleted in advanced human cancers and the expression of two Beclin-1 allelles is associated with greater anticancer effects. Overall, experimental evidence suggests that Beclin-1 inhibits tumor formation, angiogenesis, and metastasis alone and in cooperation with the tumor suppressive molecules UVRAG, Bif-1, Ambra1, and MDA-7/IL-24 via diverse mechanisms of action. Conversely, Beclin-1 is upregulated in cancer stem cells (CSCs), portending a role in cancer recurrence, and highlighting this molecule as an intriguing molecular target for the treatment of CSCs. Many aspects of Beclin-1's biological effects remain to be studied. The consequences of these BLAST searches on the molecular evolution of Beclin-1, and the eukaryotic branches of the tree of life, are discussed here in greater detail with future inquiry focused upon protist taxa. Also in this review, the effects of Beclin-1 on tumor suppression and cancer malignancy are discussed. Beclin-1 holds significant promise for the development of novel targeted cancer therapeutics and is anticipated to lead to a many advances in our understanding of eukaryotic evolution, multicellularity, and even the treatment of CSCs in the coming decades.

Post-translational modifications of high mobility group box 1 and cancer

Post-translational modifications (PTMs) of High mobility group box 1 (HMGB1) have not been investigated as extensively as those of other HMG proteins but accumulating evidence has shown the remarkable biological significances induced by the post-translational: acetylation, methylation and phosphorylation, oxidation, glycosylation and ADP-ribosylation of the HMGB1 to modulate its interactions with DNA and other proteins. Although HMGB1 is localized in the nucleus in almost all cells at baseline, it can be rapidly mobilized to other sites within the cell, including the cytoplasm and mitochondria, as well as into the extracellular; hence there is an increasing interest by researches into the complex relationship between the PTMs of HMGB1 protein and its diverse biological activities. The PTMs of HMGB1 could also have effects on gene expression following changes in its DNA-binding properties and in extracellular environment displays immunological activity and could serve as a potential target for new therapy. Our reviewed identifies covalent modifications of HMGB1, and highlighted how these PTMs affect the functions of HMGB1 protein in a variety of cellular and extra cellular processes as well as diseases and therapy.

Autophagy Roles in the Modulation of DNA Repair Pathways

Autophagy and DNA repair are biological processes vital for cellular homeostasis maintenance and when dysfunctional, they lead to several human disorders including premature aging, neurodegenerative diseases, and cancer. The interchange between these pathways is complex and it may occur in both directions. Autophagy is activated in response to several DNA lesions types and it can regulate different mechanisms and molecules involved in DNA damage response (DDR), such as cell cycle checkpoints, cell death, and DNA repair. Thus, autophagy may modulate DNA repair pathways, the main focus of this review. In addition to the already well-documented autophagy positive effects on homologous recombination (HR), autophagy has also been implicated with other DNA repair mechanisms, such as base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR). Given the relevance of these cellular processes, the clinical applications of drugs targeting this autophagy-DNA repair interface emerge as potential therapeutic strategies for many diseases, especially cancer.

Autophagic UVRAG Promotes UV-Induced Photolesion Repair by Activation of the CRL4(DDB2) E3 Ligase

UV-induced DNA damage, a major risk factor for skin cancers, is primarily repaired by nucleotide excision repair (NER). UV radiation resistance-associated gene (UVRAG) is a tumor suppressor involved in autophagy. It was initially isolated as a cDNA partially complementing UV sensitivity in xeroderma pigmentosum (XP), but this was not explored further. Here we show that UVRAG plays an integral role in UV-induced DNA damage repair. It localizes to photolesions and associates with DDB1 to promote the assembly and activity of the DDB2-DDB1-Cul4A-Roc1 (CRL4(DDB2)) ubiquitin ligase complex, leading to efficient XPC recruitment and global genomic NER. UVRAG depletion decreased substrate handover to XPC and conferred UV-damage hypersensitivity. We confirmed the importance of UVRAG for UV-damage tolerance using a Drosophila model. Furthermore, increased UV-signature mutations in melanoma correlate with reduced expression of UVRAG. Our results identify UVRAG as a regulator of CRL4(DDB2)-mediated NER and suggest that its expression levels may influence melanoma predisposition.

Nuclear localization of Beclin 1 promotes radiation-induced DNA damage repair independent of autophagy

Beclin 1 is a well-established core mammalian autophagy protein that is embryonically indispensable and has been presumed to suppress oncogenesis via an autophagy-mediated mechanism. Here, we show that Beclin 1 is a prenatal primary cytoplasmic protein but rapidly relocated into the nucleus during postnatal development in mice. Surprisingly, deletion of beclin1 in in vitro human cells did not block an autophagy response, but attenuated the expression of several DNA double-strand break (DSB) repair proteins and formation of repair complexes, and reduced an ability to repair DNA in the cells exposed to ionizing radiation (IR). Overexpressing Beclin 1 improved the repair of IR-induced DSB, but did not restore an autophagy response in cells lacking autophagy gene Atg7, suggesting that Beclin 1 may regulate DSB repair independent of autophagy in the cells exposed to IR. Indeed, we found that Beclin 1 could directly interact with DNA topoisomerase IIβ and was recruited to the DSB sites by the interaction. These findings reveal a novel function of Beclin 1 in regulation of DNA damage repair independent of its role in autophagy particularly when the cells are under radiation insult.

Retrograde signaling from autophagy modulates stress responses

Macroautophagy is a process in which cytoplasmic components, including whole organelles, are degraded within lysosomes. Basally, this process is essential for homeostasis and is constitutively functional in most cells, but it can also be implemented as part of stress responses. We discuss findings showing that autophagy proteins can modulate and amplify the activities of transcription factors involved in stress responses, such as those in the p53, FOXO, MiT/TFE, Nrf2, and NFκB/Rel families. Thus, transcription factors not only amplify stress responses and autophagy but are also subject to retrograde regulation by autophagy-related proteins. Physical interactions with autophagy-related proteins, competition for activating intermediates, and "signalphagy," which is the role autophagy plays in the degradation of specific signaling proteins, together provide powerful tools for implementing negative feedback or positive feed-forward loops on the transcription factors that regulate autophagy. We present examples illustrating how this network interacts to regulate metabolic and physiologic responses.

Krüpple-like factor 10 regulates radio-sensitivity of pancreatic cancer via UV radiation resistance-associated gene

BACKGROUND AND PURPOSE

Krüpple-like factor 10 (Klf10), an early response gene of TGFβ, was reported to be a prognostic biomarker for pancreatic cancer survival. The role of Klf10 in predicting tumor response to cancer treatment is unknown.

MATERIALS AND METHODS

Genetically manipulated MiaPaCa and Panc-1 cells were established to evaluate clonogenic survival, autophagy, apoptosis and DNA repair after radiation. The interaction between Klf10 and UV radiation resistance-associated gene (UVRAG) was demonstrated by ChiP-PCR and luciferase reporter assay. Orthotopic murine tumor model and clinical specimens were used to evaluate radio-sensitivity of pancreatic cancer.

RESULTS

We found Klf10 silencing correlates with enhanced pancreatic cancer clonogenic survival and murine tumor growth after radiation. UVRAG was an essential down-stream mediator transcriptionally suppressed by Klf10. Silencing UVRAG mRNA in Klf10 depleted Panc-1 cells reversed the radio-resistant phenotypes including decreased apoptosis and enhanced DNA repair as well as autophagy. Metformin, an anti-diabetic agent, was found to increase Klf10 and suppress UVRAG expression to improve radiation cytotoxicity in pancreatic cancer. The predictive value of Klf10 in radiation response and the inverse correlation with UVRAG were confirmed in cohorts of pancreatic cancer patients.

CONCLUSIONS

Klf10 is a potential biomarker in predicting and sensitizing radiation effect in pancreatic cancer.

Emerging role of HMGB1 in lung diseases: friend or foe

Lung diseases remain a serious problem for public health. The immune status of the body is considered to be the main influencing factor for the progression of lung diseases. HMGB1 (high‐mobility group box 1) emerges as an important molecule of the body immune network. Accumulating data have demonstrated that HMGB1 is crucially implicated in lung diseases and acts as independent biomarker and therapeutic target for related lung diseases. This review provides an overview of updated understanding of HMGB1 structure, release styles, receptors and function. Furthermore, we discuss the potential role of HMGB1 in a variety of lung diseases. Further exploration of molecular mechanisms underlying the function of HMGB1 in lung diseases will provide novel preventive and therapeutic strategies for lung diseases.

Autophagy controls centrosome number by degrading Cep63

Centrosome number is associated with the chromosome segregation and genomic stability. The ubiquitin-proteasome system is considered to be the main regulator of centrosome number. However, here we show that autophagy also regulates the number of centrosomes. Autophagy-deficient cells carry extra centrosomes. The autophagic regulation of centrosome number is dependent on a centrosomal protein of 63 (Cep63) given that cells lacking autophagy contain multiple Cep63 dots that are engulfed and digested by autophagy in wild-type cells, and that the upregulation of Cep63 increases centrosome number. Cep63 is recruited to autophagosomes via interaction with p62, a molecule crucial for selective autophagy. In vivo, hematopoietic cells from autophagy-deficient and p62^-/- mice also contained multiple centrosomes. These results indicate that autophagy controls centrosome number by degrading Cep63.

Blood miRNomes and transcriptomes reveal novel longevity mechanisms in the long-lived bat, Myotis myotis

BACKGROUND

Chiroptera, the bats, are the only order of mammals capable of true self-powered flight. Bats exhibit a number of other exceptional traits such as echolocation, viral tolerance and, perhaps most puzzlingly, extreme longevity given their body size. Little is known about the molecular mechanisms driving their extended longevity particularly at the levels of gene expression and post-transcriptional regulation. To elucidate the molecular mechanisms that may underlie their unusual longevity, we have deep sequenced 246.5 million small RNA reads from whole blood of the long-lived greater mouse-eared bats, Myotis myotis, and conducted a series of genome-wide comparative analyses between bat and non-bat mammals (human, pig and cow) in both blood miRNomes and transcriptomes, for the first time.

RESULTS

We identified 539 miRNA gene candidates from bats, of which 468 unique mature miRNA were obtained. More than half of these miRNA (65.1 %) were regarded as bat-specific, regulating genes involved in the immune, ageing and tumorigenesis pathways. We have also developed a stringent pipeline for genome-wide miRNome comparisons across species, and identified 37 orthologous miRNA groups shared with bat, human, pig and cow, 6 of which were differentially expressed. For bats, 3 out of 4 up-regulated miRNA (miR-101-3p, miR-16-5p, miR-143-3p) likely function as tumor suppressors against various kinds of cancers, while one down-regulated miRNA (miR-221-5p) acts as a tumorigenesis promoter in human breast and pancreatic cancers. Additionally, a genome-wide comparison of mRNA transcriptomes across species also revealed specific gene expression patterns in bats. 127 up-regulated genes were enriched mainly in mitotic cell cycle and DNA repair mechanisms, while 364 down-regulated genes were involved primarily in mitochondrial activity.

CONCLUSIONS

Our comprehensive and integrative analyses revealed bat-specific and differentially expressed miRNA and mRNA that function in key longevity pathways, producing a distinct bat gene expression pattern. For the first time, we show that bats may possess unique regulatory mechanisms for resisting tumorigenesis, repairing cellular damage and preventing oxidative stresses, all of which likely contribute to the extraordinary lifespan of Myotis myotis.

Stem-cell-specific endocytic degradation defects lead to intestinal dysplasia in Drosophila

UV radiation resistance-associated gene (UVRAG) is a tumor suppressor involved in autophagy, endocytosis and DNA damage repair, but how its loss contributes to colorectal cancer is poorly understood. Here, we show that UVRAG deficiency in Drosophila intestinal stem cells leads to uncontrolled proliferation and impaired differentiation without preventing autophagy. As a result, affected animals suffer from gut dysfunction and short lifespan. Dysplasia upon loss of UVRAG is characterized by the accumulation of endocytosed ligands and sustained activation of STAT and JNK signaling, and attenuation of these pathways suppresses stem cell hyperproliferation. Importantly, the inhibition of early (dynamin-dependent) or late (Rab7-dependent) steps of endocytosis in intestinal stem cells also induces hyperproliferation and dysplasia. Our data raise the possibility that endocytic, but not autophagic, defects contribute to UVRAG-deficient colorectal cancer development in humans.

Drosophila Collection: Intestinal-stem-cell-specific loss of the Drosophila ortholog of the tumor suppressor UVRAG, which is implicated in colorectal cancer, leads to endocytic defects and dysplasia.

Uvrag targeting by Mir125a and Mir351 modulates autophagy associated with Ewsr1 deficiency

The EWSR1 (EWS RNA-binding protein 1/Ewing Sarcoma Break Point Region 1) gene encodes a RNA/DNA binding protein that is ubiquitously expressed and involved in various cellular processes. EWSR1 deficiency leads to impairment of development and accelerated senescence but the mechanism is not known. Herein, we found that EWSR1 modulates the Uvrag (UV radiation resistance associated) gene at the post-transcription level. Interestingly, EWSR1 deficiency led to the activation of the DROSHA-mediated microprocessor complex and increased the level of Mir125a and Mir351, which directly target Uvrag. Moreover, the Mir125a- and Mir351-mediated reduction of Uvrag was associated with the inhibition of autophagy that was confirmed in ewsr1 knockout (KO) MEFs and ewsr1 KO mice. Taken together, our data indicate that EWSR1 is involved in the post-transcriptional regulation of Uvrag via a miRNA-dependent pathway, resulting in the deregulation of autophagy inhibition. The mechanism of Uvrag and autophagy regulation by EWSR1 provides new insights into the role of EWSR1 deficiency-related cellular dysfunction.

DAMPs, ageing, and cancer: The 'DAMP Hypothesis'

Ageing is a complex and multifactorial process characterized by the accumulation of many forms of damage at the molecular, cellular, and tissue level with advancing age. Ageing increases the risk of the onset of chronic inflammation-associated diseases such as cancer, diabetes, stroke, and neurodegenerative disease. In particular, ageing and cancer share some common origins and hallmarks such as genomic instability, epigenetic alteration, aberrant telomeres, inflammation and immune injury, reprogrammed metabolism, and degradation system impairment (including within the ubiquitin-proteasome system and the autophagic machinery). Recent advances indicate that damage-associated molecular pattern molecules (DAMPs) such as high mobility group box 1, histones, S100, and heat shock proteins play location-dependent roles inside and outside the cell. These provide interaction platforms at molecular levels linked to common hallmarks of ageing and cancer. They can act as inducers, sensors, and mediators of stress through individual plasma membrane receptors, intracellular recognition receptors (e.g., advanced glycosylation end product-specific receptors, AIM2-like receptors, RIG-I-like receptors, and NOD1-like receptors, and toll-like receptors), or following endocytic uptake. Thus, the DAMP Hypothesis is novel and complements other theories that explain the features of ageing. DAMPs represent ideal biomarkers of ageing and provide an attractive target for interventions in ageing and age-associated diseases.

mTOR activates the VPS34-UVRAG complex to regulate autolysosomal tubulation and cell survival

Lysosomes are essential organelles that function to degrade and recycle unwanted, damaged and toxic biological components. Lysosomes also act as signalling platforms in activating the nutrient-sensing kinase mTOR. mTOR regulates cellular growth, but it also helps to maintain lysosome identity by initiating lysosomal tubulation through a process termed autophagosome-lysosome reformation (ALR). Here we identify a lysosomal pool of phosphatidylinositol 3-phosphate that, when depleted by specific inhibition of the class III phosphoinositide 3-kinase VPS34, results in prolonged lysosomal tubulation. This tubulation requires mTOR activity, and we identified two direct mTOR phosphorylation sites on UVRAG (S550 and S571) that activate VPS34. Loss of these phosphorylation sites reduced VPS34 lipid kinase activity and resulted in an increase in number and length of lysosomal tubules. In cells in which phosphorylation at these UVRAG sites is disrupted, the result of impaired lysosomal tubulation alongside ALR activation is massive cell death. Our data imply that ALR is critical for cell survival under nutrient stress and that VPS34 is an essential regulatory element in this process.

Truncating mutation in the autophagy gene UVRAG confers oncogenic properties and chemosensitivity in colorectal cancers

Autophagy-related factors are implicated in metabolic adaptation and cancer metastasis. However, the role of autophagy factors in cancer progression and their effect in treatment response remain largely elusive. Recent studies have shown that UVRAG, a key autophagic tumour suppressor, is mutated in common human cancers. Here we demonstrate that the cancer-related UVRAG frameshift (FS), which does not result in a null mutation, is expressed as a truncated UVRAG(FS) in colorectal cancer (CRC) with microsatellite instability (MSI), and promotes tumorigenesis. UVRAG(FS) abrogates the normal functions of UVRAG, including autophagy, in a dominant-negative manner. Furthermore, expression of UVRAG(FS) can trigger CRC metastatic spread through Rac1 activation and epithelial-to-mesenchymal transition, independently of autophagy. Interestingly, UVRAG(FS) expression renders cells more sensitive to standard chemotherapy regimen due to a DNA repair defect. These results identify UVRAG as a new MSI target gene and provide a mechanism for UVRAG participation in CRC pathogenesis and treatment response.

CEP63 deficiency promotes p53-dependent microcephaly and reveals a role for the centrosome in meiotic recombination

CEP63 is a centrosomal protein that facilitates centriole duplication and is regulated by the DNA damage response. Mutations in CEP63 cause Seckel syndrome, a human disease characterized by microcephaly and dwarfism. Here we demonstrate that Cep63 deficient mice recapitulate Seckel syndrome pathology. The attrition of neural progenitor cells involves p53-dependent cell death and brain size is rescued by the deletion of p53. Cell death is not the result of an aberrant DNA damage response but is triggered by centrosome-based mitotic errors. In addition, Cep63 loss severely impairs meiotic recombination, leading to profound male infertility. Cep63 deficient spermatocytes display numerical and structural centrosome aberrations, chromosome entanglements and defective telomere clustering, suggesting that a reduction in centrosome-mediated chromosome movements underlies recombination failure. Our results provide novel insight into the molecular pathology of microcephaly and establish a role for the centrosome in meiotic recombination.

A systems approach identifies networks and genes linking sleep and stress: implications for neuropsychiatric disorders

Sleep dysfunction and stress susceptibility are comorbid complex traits that often precede and predispose patients to a variety of neuropsychiatric diseases. Here, we demonstrate multilevel organizations of genetic landscape, candidate genes, and molecular networks associated with 328 stress and sleep traits in a chronically stressed population of 338 (C57BL/6J × A/J) F2 mice. We constructed striatal gene co-expression networks, revealing functionally and cell-type-specific gene co-regulations important for stress and sleep. Using a composite ranking system, we identified network modules most relevant for 15 independent phenotypic categories, highlighting a mitochondria/synaptic module that links sleep and stress. The key network regulators of this module are overrepresented with genes implicated in neuropsychiatric diseases. Our work suggests that the interplay among sleep, stress, and neuropathology emerges from genetic influences on gene expression and their collective organization through complex molecular networks, providing a framework for interrogating the mechanisms underlying sleep, stress susceptibility, and related neuropsychiatric disorders.

Autophagy in malignant transformation and cancer progression

Autophagy plays a key role in the maintenance of cellular homeostasis. In healthy cells, such a homeostatic activity constitutes a robust barrier against malignant transformation. Accordingly, many oncoproteins inhibit, and several oncosuppressor proteins promote, autophagy. Moreover, autophagy is required for optimal anticancer immunosurveillance. In neoplastic cells, however, autophagic responses constitute a means to cope with intracellular and environmental stress, thus favoring tumor progression. This implies that at least in some cases, oncogenesis proceeds along with a temporary inhibition of autophagy or a gain of molecular functions that antagonize its oncosuppressive activity. Here, we discuss the differential impact of autophagy on distinct phases of tumorigenesis and the implications of this concept for the use of autophagy modulators in cancer therapy.

Roles of autophagy induced by natural compounds in prostate cancer

Autophagy is a homeostatic mechanism through which intracellular organelles and proteins are degraded and recycled in response to increased metabolic demand or stress. Autophagy dysfunction is often associated with many diseases, including cancer. Because of its role in tumorigenesis, autophagy can represent a new therapeutic target for cancer treatment. Prostate cancer (PCa) is one of the most common cancers in aged men. The evidence on alterations of autophagy related genes and/or protein levels in PCa cells suggests a potential implication of autophagy in PCa onset and progression. The use of natural compounds, characterized by low toxicity to normal tissue associated with specific anticancer effects at physiological levels in vivo, is receiving increasing attention for prevention and/or treatment of PCa. Understanding the mechanism of action of these compounds could be crucial for the development of new therapeutic or chemopreventive options. In this review we focus on the current evidence showing the capacity of natural compounds to exert their action through autophagy modulation in PCa cells.