A CANCER PERSISTENT DNA REPAIR CIRCUIT DRIVEN BY MDM2, MDM4 (MDMX), AND MUTANT P53 FOR RECRUITMENT OF MDC1 AND 53BP1 TO CHROMATIN.

The influence of the metastasis promoting proteins mutant p53 (mtp53) and MDM2 on Cancer Persistent Repair (CPR) to promote cancer cell survival is understudied. Interactions between the DNA repair choice protein 53BP1 and wild type tumor suppressor protein p53 (wtp53) regulates cell cycle control. Cancer cells often express elevated levels of transcriptionally inactive missense mutant p53 (mtp53) that interacts with MDM2 and MDM4/MDMX (herein called MDMX). The ability of mtp53 to maintain a 53BP1 interaction while in the context of interactions with MDM2 and MDMX has not been described. We asked if MDM2 regulates chromatin-based phosphorylation events in the context of mtp53 by comparing the chromatin of T47D breast cancer cells with and without MDM2 in a phospho-peptide stable isotope labeling in cell culture (SILAC) screen. We found reduced phospho-53BP1 chromatin association, which we confirmed by chromatin fractionation and immunofluorescence in multiple breast cancer cell lines. We used the Proximity Ligation Assay (PLA) in breast cancer cell lines and detected 53BP1 in close proximity to mtp53, MDM2, and the DNA repair protein MDC1. Through disruption of the mtp53-MDM2 interaction, by either Nutlin 3a or a mtp53 R273H C-terminal deletion, we uncovered that mtp53 was required for MDM2-53BP1 interaction foci. Our data suggests that mtp53 works with MDM2 and 53BP1 to promote CPR and cell survival.

Patient-derived tumor organoids with p53 mutations, and not wild-type p53, are sensitive to synergistic combination PARP inhibitor treatment.

Poly (ADP-ribose) polymerase inhibitors (PARPi) are used for patients with BRCA1/2 mutations, but patients with other mutations may benefit from PARPi treatment. Another mutation that is present in more cancers than BRCA1/2 is mutation to the TP53 gene. In 2D breast cancer cell lines, mutant p53 (mtp53) proteins tightly associate with replicating DNA and Poly (ADP-ribose) polymerase (PARP) protein. Combination drug treatment with the alkylating agent temozolomide and the PARPi talazoparib kills mtp53 expressing 2D grown breast cancer cell lines. We evaluated the sensitivity to the combination of temozolomide plus PARPi talazoparib treatment to breast and lung cancer patient-derived tumor organoids (PDTOs). The combination of the two drugs was synergistic for a cytotoxic response in PDTOs with mtp53 but not for PDTOs with wtp53. The combination of talazoparib and temozolomide induced more DNA double-strand breaks in mtp53 expressing organoids than in wild-type p53 expressing organoids as shown by increased γ-H2AX protein expression. Moreover, breast cancer tissue microarrays (TMAs) showed a positive correlation between stable p53 and high PARP1 expression in sub-groups of breast cancers, which may indicate sub-classes of breast cancers sensitive to PARPi therapy. These results suggest that mtp53 could be a biomarker to predict response to the combination of PARPi talazoparib-temozolomide treatment.

Patient-derived tumor organoids with p53 mutations, and not wild-type p53, are sensitive to synergistic combination PARP inhibitor treatment.

Poly (ADP-ribose) polymerase inhibitors (PARPi) are used for patients with BRCA1/2 mutations, but patients with other mutations may benefit from PARPi treatment. Another mutation that is present in more cancers than BRCA1/2 is mutation to the TP53 gene. In 2D breast cancer cell lines, mutant p53 (mtp53) proteins tightly associate with replicating DNA and Poly (ADP-ribose) polymerase (PARP) protein. Combination drug treatment with the alkylating agent temozolomide and the PARPi talazoparib kills mtp53 expressing 2D grown breast cancer cell lines. We evaluated the sensitivity to the combination of temozolomide plus PARPi talazoparib treatment to breast and lung cancer patient-derived tumor organoids (PDTOs). The combination of the two drugs was synergistic for a cytotoxic response in PDTOs with mtp53 but not for PDTOs with wtp53. The combination of talazoparib and temozolomide induced more DNA double-strand breaks in mtp53 expressing organoids than in wild-type p53 expressing organoids as shown by increased γ-H2AX protein expression. Moreover, breast cancer tissue microarrays (TMAs) showed a positive correlation between stable p53 and high PARP1 expression in sub-groups of breast cancers, which may indicate sub-classes of breast cancers sensitive to PARPi therapy. These results suggest that mtp53 could be a biomarker to predict response to the combination of PARPi talazoparib-temozolomide treatment.

Maternal dominance contributes to subgenome differentiation in allopolyploid fishes.

Teleost fishes, which are the largest and most diverse group of living vertebrates, have a rich history of ancient and recent polyploidy. Previous studies of allotetraploid common carp and goldfish (cyprinids) reported a dominant subgenome, which is more expressed and exhibits biased gene retention. However, the underlying mechanisms contributing to observed 'subgenome dominance' remains poorly understood. Here we report high-quality genomes of twenty-one cyprinids to investigate the origin and subsequent subgenome evolution patterns following three independent allopolyploidy events. We identify the closest extant relatives of the diploid progenitor species, investigate genetic and epigenetic differences among subgenomes, and conclude that observed subgenome dominance patterns are likely due to a combination of maternal dominance and transposable element densities in each polyploid. These findings provide an important foundation to understanding subgenome dominance patterns observed in teleost fishes, and ultimately the role of polyploidy in contributing to evolutionary innovations.

Nanopolyphenol rejuvenates microglial surveillance of multiple misfolded proteins through metabolic reprogramming

Microglial surveillance plays an essential role in clearing misfolded proteins such as amyloid-beta, tau, and α-synuclein aggregates in neurodegenerative diseases. However, due to the complex structure and ambiguous pathogenic species of the misfolded proteins, a universal approach to remove the misfolded proteins remains unavailable. Here, we found that a polyphenol, α-mangostin, reprogrammed metabolism in the disease-associated microglia through shifting glycolysis to oxidative phosphorylation, which holistically rejuvenated microglial surveillance capacity to enhance microglial phagocytosis and autophagy-mediated degradation of multiple misfolded proteins. Nanoformulation of α-mangostin efficiently delivered α-mangostin to microglia, relieved the reactive status and rejuvenated the misfolded-proteins clearance capacity of microglia, which thus impressively relieved the neuropathological changes in both Alzheimer's disease and Parkinson's disease model mice. These findings provide direct evidences for the concept of rejuvenating microglial surveillance of multiple misfolded proteins through metabolic reprogramming, and demonstrate nanoformulated α-mangostin as a potential and universal therapy against neurodegenerative diseases.

Mechanism of regulating immune dysfunction of sepsis based on network pharmacology and experimental verification / 中国药理学通报

Aim To verify the role of Shengjiang Powder in sepsis and explore its molecular mechanism. Methods The targets of drug active ingredients and disease-related targets were searched by TCMSP, Disgenet and other databases, and the intersection of the two was selected. DAVID database was used to carry out enrichment analysis of GO and KEGG pathways for intersection targets, and molecular docking was performed between drug active ingredients and core genes of key pathways. Mouse model of sepsis was constructed by cecal ligation puncture (CLP). Spleen tissue and serum of mice were collected. The percentage of T cell subsets in spleen was detected by flow cytometry, and IL-6 and IL-10 levels in serum were detected by ELISA. Results A total of 25 active ingredients, 238 targets of active ingredients, 2797 disease-related targets, 90 genes of intersection between active ingredients and disease-related targets, potential targets were AKT, JUN, EGFR, MMP9, etc. GO enrichment analysis showed 1021 items, including 942 biological processes, 23 cell compositions and 55 molecular functions. KEGG pathway analysis found that the intersection genes were mainly enriched in THE PD-1/PD-L1 signaling pathway, HIF-1 signaling pathway, TNF signaling pathway and inflammatory mediators signaling pathway, indicating that the therapeutic effect may be related to these pathways. The molecular docking results showed that quercetin, kamanol, emodin and other core compounds could be well combined with key genes. Flow cytometry results showed that after seven days of CLP, the proportion of CD4 T cells in spleen decreased, the proportion of CD4 PD-1 T cells increased, the release of IL-6 decreased, the content of IL-10 increased, and the mice were immunosuppressed. The percentage of CD4 T cells in spleen increased, the number of CD4 PD-1 T cells decreased, the release of IL-6 was enhanced, the content of IL-10 decreased, and the immunosuppression was improved. Conclusions It is proved that Shengjiang Powder can increase the release of pro-inflammatory cytokine IL-6, increase the ratio of CD4 T/CD8 T cells, and decrease the expression of anti-inflammatory cytokine IL-10 in the late stage of sepsis, so as to improve immune suppression in the late stage of sepsis and improve the survival rate of mice.

Investigation of potential pharmacodynamic substances and mechanism of Qingxin-zishen prescription decoction in treatment of menopause syndrome based on HPLC-Q-TOF-MS/MS and network pharmacology / 中国临床药理学与治疗学

AIM: To analyze the chemical ingredients of Qingxin-zishen prescription decoction (QZPD) and predict its main pharmacodynamic substances and mechanism in the prevention and treatment of menopause syndrome (MPS) with the help of high performance liquid chromatography-quadrupole-time of flight mass spectrometry (HPLC-Q-TOF/MS) combined with network pharmacology. METHODS: The chemical ingredients of QZPD were identified after analyzing the retention time, exact mass, secondary mass spectrometry fragmentation and other information obtained from HPLC-Q-TOF/MS and comparing them with the established chemical ingredients database and the literatures. The targets of ingredients in QZPD were predicted by Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and SwissTargetPrediction database. The disease targets of MPS were obtained through Online Mendelian Inheritance in Man (OMIM) and GeneCards Database. Gene ontology (GO) function enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of potential targets were analyzed with the Metascape database. Cytoscape 3.7.2 software was used to construct the network of active components-key targets-pathways. AutoDockTools 4.2.5 software was applied in the molecular docking verification between the key active components and key targets. RESULTS: A total of 83 components were identified in QZPD and 847 drug targets were predicted. After intersection them with 3 050 disease targets, 395 common targets were obtained. After network topology analysis, 74 key targets were obtained, involving mitogen-activated protein kinase (MAPK), phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt), transforming growth factor-β (TGF-β) and other signaling pathways. Molecular docking analysis results indicated that 23 key active components, such as berberine, epiberberine, coptisine, geissoschizine methyl ether, liensinine, norcoclaurine, palmatine, quercetin, and luteolin, had good binding activity with several of the key targets. CONCLUSION: This study preliminarily identifies the potential effective chemical ingredients of QZPD, predicts its targets in the prevention and treatment of MPS, which provides supporting information for the further study of the pharmacodynamic substances and mechanisms of QZPD.

Oligomerization of Mutant p53 R273H is not Required for Gain-of-Function Chromatin Associated Activities.

The TP53 gene is often mutated in cancer, with missense mutations found in the central DNA binding domain, and less often in the C-terminal oligomerization domain (OD). These types of mutations are found in patients with the rare inherited cancer predisposition disorder called Li-Fraumeni syndrome. We previously found that mutant p53 (mtp53) R273H associates with replicating DNA and promotes the chromatin association of replication-associated proteins mini-chromosome maintenance 2 (MCM2), and poly ADP-ribose polymerase 1(PARP1). Herein, we created dual mutants in order to test if the oligomerization state of mtp53 R273H played a role in chromatin binding oncogenic gain-of-function (GOF) activities. We used site-directed mutagenesis to introduce point mutations in the OD in wild-type p53 (wtp53), and mtp53 R273H expressing plasmids. The glutaraldehyde crosslinking assay revealed that both wtp53 and mtp53 R273H formed predominantly tetramers, while the single OD mutant A347D, and the dual mtp53 R273H-A347D, formed predominantly dimers. The R337C, L344P, mtp53 R273H-R337C, and mtp53 R273H-L344P proteins formed predominantly monomers. Wtp53 was able to activate the cyclin-dependent kinase gene p21/waf and the p53 feedback regulator MDM2. As expected, the transactivation activity was lost for all the single mutants, as well as the mtp53 R273H-dual mutants. Importantly, mtp53 R273H and the dual oligomerization mutants, R273H-A347D, R273H-R337C, and R273H-L344P were able to interact with chromatin. Additionally, the dual oligomerization mutants, R273H-A347D, R273H-R337C, and R273H-L344P, maintained strong interactions with MCM2 and PARP1. Our findings suggest that while mtp53 R273H can form tetramers, tetramer formation is not required for the GOF associated chromatin interactions.

PARP-Targeted Auger Therapy in p53 Mutant Colon Cancer Xenograft Mouse Models.

Despite Auger electrons being highly appealing due to their short-range and high linear energy transfer to surrounding tissues, the progress in the field has been limited due to the challenge in delivering a therapeutic dose within the close proximity of cancer cell's DNA. Here, we demonstrate that the PARP inhibitor 123I-MAPi is a viable agent for the systemic administration and treatment of p53 mutant cancers. Significantly, minimal off-site toxicity was observed in mice administered with up to 74 MBq of 127I-PARPi. Taken together, these results lay the foundation for future clinical evaluation and broader preclinical investigations. By harnessing the scaffold of the PARP inhibitor Olaparib, we were able to deliver therapeutic levels of Auger radiation to the site of human colorectal cancer xenograft tumors after systemic administration. In-depth toxicity studies analyzed blood chemistry levels and markers associated with specific organ toxicity. Finally, p53+/+ and p53-/- human colorectal cancer cell lines were evaluated for the ability of 123I-MAPi to induce tumor growth delay. Toxicity studies demonstrate that both 123I-MAPi and its stable isotopologue, 127I-PARPi, have no significant off-site toxicity when administered systemically. Analysis following 123I-MAPi treatment confirmed its ability to induce DNA damage at the site of xenograft tumors when administered systemically. Finally, we demonstrate that 123I-MAPi generates a therapeutic response in p53-/-, but not p53+/+, subcutaneous xenograft tumors in mouse models. Taken together, these results represent the first example of a PARP Auger theranostic agent capable of delivering a therapeutic dose to xenograft human colorectal cancer tumors upon systemic administration without causing significant toxicity to surrounding mouse organs. Moreover, it suggests that a PARP Auger theranostic can act as a targeted therapeutic for cancers with mutated p53 pathways. This landmark goal paves the way for clinical evaluation of 123I-MAPi for pan cancer therapeutics.

Frame-shift mediated reduction of gain-of-function p53 R273H and deletion of the R273H C-terminus in breast cancer cells result in replication-stress sensitivity.

We recently documented that gain-of-function (GOF) mutant p53 (mtp53) R273H in triple negative breast cancer (TNBC) cells interacts with replicating DNA and PARP1. The missense R273H GOF mtp53 has a mutated central DNA binding domain that renders it unable to bind specifically to DNA, but maintains the capacity to interact tightly with chromatin. Both the C-terminal domain (CTD) and oligomerization domain (OD) of GOF mtp53 proteins are intact and it is unclear whether these regions of mtp53 are responsible for chromatin-based DNA replication activities. We generated MDA-MB-468 cells with CRISPR-Cas9 edited versions of the CTD and OD regions of mtp53 R273H. These included a frame-shift mtp53 R273Hfs387, which depleted mtp53 protein expression; mtp53 R273HΔ381-388, which had a small deletion within the CTD; and mtp53 R273HΔ347-393, which had both the OD and CTD regions truncated. The mtp53 R273HΔ347-393 existed exclusively as monomers and disrupted the chromatin interaction of mtp53 R273H. The CRISPR variants proliferated more slowly than the parental cells and mt53 R273Hfs387 showed the most extreme phenotype. We uncovered that after thymidine-induced G1/S synchronization, but not hydroxyurea or aphidicholin, R273Hfs387 cells displayed impairment of S-phase progression while both R273HΔ347-393 and R273HΔ381-388 displayed only moderate impairment. Moreover, reduced chromatin interaction of MCM2 and PCNA in mtp53 depleted R273Hfs387 cells post thymidine-synchronization revealed delayed kinetics of replisome assembly underscoring the slow S-phase progression. Taken together our findings show that the CTD and OD domains of mtp53 R273H play critical roles in mutant p53 GOF that pertain to processes associated with DNA replication.

Targeting Triple Negative Breast Cancer with a Nucleus-Directed p53 Tetramerization Domain Peptide.

Triple negative breast cancer (TNBC) has no targeted detection or treatment method. Mutant p53 (mtp53) is overexpressed in >80% of TNBCs, and the stability of mtp53 compared to the instability of wild-type p53 (wtp53) in normal cells makes mtp53 a promising TNBC target for diagnostic and theranostic imaging. We generated Cy5p53Tet, a novel nucleus-penetrating mtp53-oligomerization-domain peptide (mtp53ODP) to the tetramerization domain (TD) of mtp53. This mtp53ODP contains the p53 TD sequence conjugated to a Cy5 fluorophore for near-infrared fluorescence imaging (NIRF). In vitro co-immunoprecipitation and glutaraldehyde cross-linking showed a direct interaction between mtp53 and Cy5p53Tet. Confocal microscopy and flow cytometry demonstrated higher uptake of Cy5p53Tet in the nuclei of TNBC MDA-MB-468 cells with mtp53 R273H than in ER-positive MCF7 cells with wtp53. Furthermore, depletion of mtp53 R273H caused a decrease in the uptake of Cy5p53Tet in nuclei. In vivo analysis of the peptide in mice bearing MDA-MB-468 xenografts showed that Cy5p53Tet could be detected in tumor tissue 12 min after injection. In these in vivo experiments, significantly higher uptake of Cy5p53Tet was observed in mtp53-expressing MDA-MB-468 xenografts compared with the wtp53-expressing MCF7 tumors. Cy5p53Tet has clinical potential as an intraoperative imaging agent for fluorescence-guided surgery, and the mtp53ODP scaffold shows promise for modification in the future to enable the delivery of a wide variety of payloads including radionuclides and toxins to mtp53-expressing TNBC tumors.

MDM2-C Functions as an E3 Ubiquitin Ligase.

BACKGROUND: Mouse double minute 2 (MDM2) is an E3 ubiquitin ligase that is over-expressed in many cancers and regulates target proteins through ubiquitination. Full-length MDM2 (MDM2-FL) is best known for targeting wild-type p53 for degradation by the proteasome, but the functions of the many splice variants of MDM2 are under-explored. The three well-studied alternative MDM2 isoforms are MDM2-A/ALT2, MDM2-B/ALT1, and MDM2-C/ALT3. MDM2-A and MDM2-B are capable of down-regulating MDM2-FL activity and have transforming activity in cancers with mutant p53. The MDM2 isoform MDM2-C is over-expressed in breast cancer and correlates with decreased survival in the context of mutant p53 expression. Therefore, MDM2-C requires further study to determine if it has biochemical activities similar to MDM2-FL. Hypothesis: We hypothesized that like MDM2-FL, the MDM2-C isoform (lacking exons 5-9 and containing a full C-terminal RING finger sequence) would maintain E3 ubiquitin ligase activity. MATERIALS AND METHODS: In order to explore the biochemical function of MDM2-C, we used an in vitro ubiquitination assay and a glutaraldehyde cross-linking assay. RESULTS: Here we report, for the first time, that MDM2-C has E3 auto-ubiquitin ligase activity, which can promote ubiquitination of wild-type p53 and mutant p53 R273H, and also can form a protein-protein interaction with p53 proteins. CONCLUSION: This information strongly positions MDM2-C as a protein with biochemical activities that may explain the varied outcomes observed in patients with high-level expression of MDM2-C in the presence of wild-type p53 versus mutant p53.

Analysis of related factors of optical quality in healthy Chinese adults: a community-based population study.

BACKGROUND: In recent years, visual quality has been extensively investigated in various conditions. In this community-based population study, we analyzed the effects of aging, refraction, and Lens Opacification Classification System III (LOCSIII) score on retinal imaging quality in healthy Chinese adults. METHODS: This cross-sectional study was conducted on sub-group subjects from The Handan Eye Study between October 2012 and January 2013. Healthy subjects over 30-years-old with logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) less than 0 were included. Retinal image quality was measured by optical quality analysis system (OQAS) and recorded as modulation transfer function cutoff frequency (MTFcutoff), OQAS value (OV) 100%, OV20%, OV9%, Strehl ratio (SR), and objective scatter index (OSI). The correlation between age, spherical equivalent refraction (SE), LOCSIII score, and optical quality parameters were investigated by multivariate analysis. RESULTS: Among 1108 verified subjects, 690 subjects (1380 eyes) met the inclusion criteria. Their age ranged from 30 to 76 years, SE ranged from -4.75 to 2.75 D. They were divided into five age groups (30-39, 40-49, 50-59, 60-69, and ≥70 years) for further analysis. After multivariate analysis by mixed-effect linear model, SR (t =  -3.03, P = 0.002), OV20% (t = -2.39, P = 0.017), and OV9% (t = -3.16, P = 0.001) significantly decreased with the increasing age, whereas logMAR BCVA (t = 4.42, P < 0.001) and OSI (t = 4.46, P < 0.001) significantly increased with age. As SE increased, SR (t = 2.74, P = 0.01), OV20% (t = 2.31, P = 0.02), and OV9% (t = 2.79, P = 0.005) significantly elevated, and OSI (t = -3.38, P < 0.001) significantly decreased. With the increase in cortical opacity score, all optical quality parameters except for SR significantly decreased, including MTFcutoff (t = -2.78, P = 0.01), OV100% (t = -2.78, P = 0.005), OV20% (t = -2.60, P = 0.009), and OV9% (t = -2.05, P = 0.040). As posterior sub capsular opacity score increased, MTFcutoff (t = -2.40, P = 0.02) and OV100% (t = -2.40, P = 0.01) significantly decreased, while OSI (t = 7.56, P < 0.001) significantly increased. CONCLUSIONS: In healthy Chinese adult population, optical quality-related parameters significantly decrease with the increasing age, and OSI significantly increases with age. In normal BCVA subjects, optical quality is significantly impacted by cortical and posterior sub capsular opacity rather than by nuclear opacity.

High-quality genome assembly and transcriptome of Ancherythroculter nigrocauda, an endemic Chinese cyprinid species.

Ancherythroculter nigrocauda is a cyprinid fish endemic of the upper reaches of the Yangtze River in China, where it is an important aquaculture and commercial species. It is also a threatened species as a result of overfishing, dam construction and water pollution. In this study, a chromosome-level genome assembly of A. nigrocauda is reported and built using PacBio sequencing and the Hi-C technology. The 1.04-Gb sequenced genome of A. nigrocauda contained 2,403 contigs, with an N50 length of 3.12 Mb. Then, 1,297 contigs, which represented 54.0% of all contigs and 97.2% of the whole content of the genome nucleotide base, were assembled into 24 chromosomes. Combined with transcriptome data from 10 tissues, 27,042 (78.5%) genes were functionally annotated out of 34,414 predicted protein-coding genes. Interestingly, high expression of many positively selected genes and expanded gene families in the brain suggested that these genes might play important roles in brain development in A. nigrocauda. Finally, we found tissue-specific expression of 10,732 genes. Functional analyses showed that they were mainly composed of genes related to (a) environmental information processing, (b) the circulatory system, and (c) development, suggesting they might be important for adaptation to different environments and for development of A. nigrocauda. The high-quality genome obtained in this study not only provides a valuable genomic resource for future studies of A. nigrocauda populations and conservation, but is also an important resource for further functional genomics studies of fishes.

Horizontal transfer and evolution of transposable elements in vertebrates.

Horizontal transfer of transposable elements (HTT) is an important process shaping eukaryote genomes, yet very few studies have quantified this phenomenon on a large scale or have evaluated the selective constraints acting on transposable elements (TEs) during vertical and horizontal transmission. Here we screen 307 vertebrate genomes and infer a minimum of 975 independent HTT events between lineages that diverged more than 120 million years ago. HTT distribution greatly differs from null expectations, with 93.7% of these transfers involving ray-finned fishes and less than 3% involving mammals and birds. HTT incurs purifying selection (conserved protein evolution) on all TEs, confirming that producing functional transposition proteins is required for a TE to invade new genomes. In the absence of HTT, DNA transposons appear to evolve neutrally within genomes, unlike most retrotransposons, which evolve under purifying selection. This selection regime indicates that proteins of most retrotransposon families tend to process their own encoding RNA (cis-preference), which helps retrotransposons to persist within host lineages over long time periods.

Gain-of-Function Mutant p53 R273H Interacts with Replicating DNA and PARP1 in Breast Cancer.

Over 80% of triple-negative breast cancers (TNBC) express mutant p53 (mtp53) and some contain oncogenic gain-of-function (GOF) p53. We previously reported that GOF mtp53 R273H upregulates the chromatin association of mini chromosome maintenance (MCM) proteins MCM2-7 and PARP and named this the mtp53-PARP-MCM axis. In this study, we dissected the function and association between mtp53 and PARP using a number of different cell lines, patient-derived xenografts (PDX), tissue microarrays (TMA), and The Cancer Genome Atlas (TCGA) database. Endogenous mtp53 R273H and exogenously expressed R273H and R248W bound to nascent 5-ethynyl-2´-deoxyuridine-labeled replicating DNA. Increased mtp53 R273H enhanced the association of mtp53 and PARP on replicating DNA. Blocking poly-ADP-ribose gylcohydrolase also enhanced this association. Moreover, mtp53 R273H expression enhanced overall MCM2 levels, promoted cell proliferation, and improved the synergistic cytotoxicity of treatment with the alkylating agent temozolomide in combination with the PARP inhibitor (PARPi) talazoparib. Staining of p53 and PARP1 in breast cancer TMAs and comparison with the TCGA database indicated a higher double-positive signal in basal-like breast cancer than in luminal A or luminal B subtypes. Higher PARP1 protein levels and PAR proteins were detected in mtp53 R273H than in wild-type p53-expressing PDX samples. These results indicate that mtp53 R273H and PARP1 interact with replicating DNA and should be considered as dual biomarkers for identifying breast cancers that may respond to combination PARPi treatments. SIGNIFICANCE: p53 gain-of-function mutant 273H and PARP1 interact with replication forks and could serve as potential biomarkers for breast cancer sensitivity to PARP inhibitors. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/3/394/F1.large.jpg.

Biosynthetic pathways of Polygonatum cyrtonema polysaccharide and diosgenin based on its transcriptomic data / 中国中药杂志

Polygonatum cyrtonema belongs to the plant family Liliaceae, and its dried rhizome is one of the sources of Chinese traditional medicine of Polygonati Rhizoma. It possesses the dual function as both medicine and food. Its main chemical components are polysaccharides and saponins. In order to understand the biosynthesis pathway of polysaccharides and diosgenin in P. cyrtonema, the corresponding transcriptomic data were obtained by extracting and sequencing the RNA of four parts of P. cyrtonema, namely, leaves, stems, rhizomes and roots. By adopting BGISEQ-500 sequencing platform, 42.03 Gb data were retrieved. Subsequently, the de novo assembly was carried out by Trinity software to obtain 137 233 transcripts, of which 68.13% of unigenes were annotated in seven databases including KEGG, GO, NR, NT, SwissProt, Pfam and KOG. Transcripts that may be involved in the biosynthesis of polysaccharides and diosgenin were analyzed by data mining. With help of qPCR, we validated expression data of four genes that were possibly involved in the biosynthesis of target metabolites. This experiment provides data for the study of biosynthetic pathways of P. cyrtonema secondary metabolites and the clarification of related structural gene functions.

Analysis of related factors of optical quality in healthy Chinese adults: a community-based population study / 中华医学杂志(英文版)

BACKGROUND@#In recent years, visual quality has been extensively investigated in various conditions. In this community-based population study, we analyzed the effects of aging, refraction, and Lens Opacification Classification System III (LOCSIII) score on retinal imaging quality in healthy Chinese adults.@*METHODS@#This cross-sectional study was conducted on sub-group subjects from The Handan Eye Study between October 2012 and January 2013. Healthy subjects over 30-years-old with logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) less than 0 were included. Retinal image quality was measured by optical quality analysis system (OQAS) and recorded as modulation transfer function cutoff frequency (MTFcutoff), OQAS value (OV) 100%, OV20%, OV9%, Strehl ratio (SR), and objective scatter index (OSI). The correlation between age, spherical equivalent refraction (SE), LOCSIII score, and optical quality parameters were investigated by multivariate analysis.@*RESULTS@#Among 1108 verified subjects, 690 subjects (1380 eyes) met the inclusion criteria. Their age ranged from 30 to 76 years, SE ranged from -4.75 to 2.75 D. They were divided into five age groups (30-39, 40-49, 50-59, 60-69, and ≥70 years) for further analysis. After multivariate analysis by mixed-effect linear model, SR (t =  -3.03, P = 0.002), OV20% (t = -2.39, P = 0.017), and OV9% (t = -3.16, P = 0.001) significantly decreased with the increasing age, whereas logMAR BCVA (t = 4.42, P < 0.001) and OSI (t = 4.46, P < 0.001) significantly increased with age. As SE increased, SR (t = 2.74, P = 0.01), OV20% (t = 2.31, P = 0.02), and OV9% (t = 2.79, P = 0.005) significantly elevated, and OSI (t = -3.38, P < 0.001) significantly decreased. With the increase in cortical opacity score, all optical quality parameters except for SR significantly decreased, including MTFcutoff (t = -2.78, P = 0.01), OV100% (t = -2.78, P = 0.005), OV20% (t = -2.60, P = 0.009), and OV9% (t = -2.05, P = 0.040). As posterior sub capsular opacity score increased, MTFcutoff (t = -2.40, P = 0.02) and OV100% (t = -2.40, P = 0.01) significantly decreased, while OSI (t = 7.56, P < 0.001) significantly increased.@*CONCLUSIONS@#In healthy Chinese adult population, optical quality-related parameters significantly decrease with the increasing age, and OSI significantly increases with age. In normal BCVA subjects, optical quality is significantly impacted by cortical and posterior sub capsular opacity rather than by nuclear opacity.

Contemplations on MDMX (MDM4) driving triple negative breast cancer circulating tumor cells and metastasis.

MDMX (MDM4) is emerging as an important breast cancer (BC) biomarker, and oncoprotein, that can be targeted in combination with its well-known family member MDM2. While MDM2 has previously been implicated in driving BC metastasis, information about the role of MDMX in driving circulating tumor cells (CTCs) and BC metastasis is lacking. BCs often have alterations of MDM2, MDMX, and mutant p53 (mtp53). Therefore, the role of MDM2 and MDMX in the context of mtp53 in BCs requires further clarification. Our group has recently reported that triple negative breast cancer (TNBC) metastasis is dependent on both MDM2 and MDMX, and depleting MDM2 results in increased MDMX, but depleting MDMX does not cause an increase in MDM2. In the context of human TNBC expressing mtp53 in an orthotopic mouse model the down-regulation of MDMX virtually cleared CTCs from the blood. Contemplations, using the available literature, suggest that disrupting the stability and/or function of MDMX protein (and its downstream targets), in the context of mtp53 expressing BCs, might be beneficial for patient survival. It remains to be determined if blocking mtp53-MDMX pathways can inhibit early stage TNBC and eliminate CTCs that have the potential to form metastatic lesions.

Successful Invasions of Short Internally Deleted Elements (SIDEs) and Its Partner CR1 in Lepidoptera Insects.

Although DNA transposons often generated internal deleted derivatives such as miniature inverted-repeat transposable elements, short internally deleted elements (SIDEs) derived from nonlong terminal-repeat retrotransposons are rare. Here, we found a novel SIDE, named Persaeus, that originated from the chicken repeat 1 (CR1) retrotransposon Zenon and it has been found widespread in Lepidoptera insects. Our findings suggested that Persaeus and the partner Zenon have experienced a transposition burst in their host genomes and the copy number of Persaeus and Zenon in assayed genomes are significantly correlated. Accordingly, the activity though age analysis indicated that the replication wave of Persaeus coincided with that of Zenon. Phylogenetic analyses suggested that Persaeus may have evolved at least four times independently, and that it has been vertically transferred into its host genomes. Together, our results provide new insights into the evolution dynamics of SIDEs and its partner non-LTRs.