Tp53 Mutation Inhibits Ubiquitination and Degradation of WISP1 via Down-Regulation of Siah1 in Pancreatic Carcinogenesis

Wnt1 inducible signaling pathway protein-1 (WISP1) may play an important role in promoting carcinogenesis. However, the biological function and underlying mechanism of WISP1 in pancreatic carcinogenesis still remains enigmatic. In this study, immunochemistry staining showed that protein levels of WISP1 were more significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) tissues with Tp53 mutation than in PDAC tissues with Tp53 wild-type. In addition, a significant correlation was observed between increased malignant phenotype of tumors from well-differentiated adenocarcinoma tissues to moderately- or poorly-differentiated adenocarcinoma tissues shifting from cytoplasmic expression to nuclear accumulation of WISP1. Interestingly, WISP1 expression was correlated with the poor prognosis in PDAC patients with Tp53 mutation. Also, the biological function analysis showed that WISP1 may act as a potential oncogene in PDAC cells. In addition, immunofluorescence analysis showed that Tp53 mutation promoted WISP1 expression in PanIN and PDAC cells, while Siah E3 Ubiquitin Protein Ligase 1 (Siah1) inhibited WISP1 expression in PDAC cells. Moreover, through immunoprecipitation, immunoblotting analysis, in vitro binding assay, and ubiquitination assay, we found that Tp53 mutation inhibited ubiquitination and degradation of Siah1-dependent WISP1. Therefore, Tp53 mutation-Siah1-WISP1 is a new signaling pathway, playing an important role in pancreatic carcinogenesis.

[Pathogen spectrum in enteroviral infections among children in Beijing from 2010 to 2016]

Objective: To understand the epidemiological and etiological characteristics of enterovirus (EV)-associated diseases among children in Beijing from 2010 to 2016. Methods: This was a repeated cross-sectional study. The throat swabs were collected from children with probable EV-associated diseases at the Children' s Hospital Affiliated to Capital Institute of Pediatrics from 2010 to 2016. The samples were sent for pan-EV, enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16) detection by real-time fluorescence reverse transcription polymerase chain reaction (RT-PCR) . The viral types of non-EV-A71 and non-CV-A16 EV-positive samples were identified using modified RT-PCR and sequencing with CV-A6, EV-A/B group and 5 'UTR universal primers. The constituent ratios of the prevalence of different EV types in different age and gender groups were compared. Results: Of the 2 703 throat swabs, 1 992 (73.7%) samples were positive for EV, including EV-A71 (19.1%, 516/2 703), CV-A16 (24.3%, 658/2 703), CV-A6 (22.2%, 600/2 703), CV-A10 (4.5%, 122/2 703) and other types of EV (3.5%, 95/2 703). There was 1 case of EV-A71 and CV-A16 co-infection. The positive detection rate of EV-A group (excluding EV-A71, CV-A16, CV-A6 and CV-A10) increased from 11.3% (7/62) to 95.2% (59/62) after using the modified VP1-specific primers and PCR amplification conditions. During the period between 2010 and 2012, CV-A16 and EV-A71 predominated in EV-positive samples. However, CV-A6 accounted for 60.7% (68/112) in 2013, much higher than CV-A16 (23.2%, 26/112) and EV-A71 (12.5%, 14/112). In 2014, EVs were mainly of CV-A16 and EV-A71, but CV-A6 was the predominant type in 2015 (68.2%, 232/340) and in 2016 (38.6%, 151/391). The epidemic season of EVs was mostly from April to August, but CV-A6 showed a small epidemic peak from October to November. The male-to-female ratio of EV-positive patients was 1.50∶1, and EV-associated diseases mostly occurred in children under 5 years of age. Younger children were more susceptible to CV-A6 than to EV-A71 and CV-A16. Conclusions: From 2010 to 2016, there was a significant change in the spectrum of EVs in children with EV-associated diseases in Beijing. Since 2013, non-EV-A71 and non-CV-A16 increased, and CV-A6 gradually became one of the major pathogens of EV-associated diseases. The modified PCR primers and amplification conditions can effectively improve the reliability of test results.

The assessment of the eco-toxicological effect of gabapentin on early development of zebrafish and its antioxidant system

Gabapentin (GAB) is an emerging contaminant that is frequently detected in water bodies across the globe. The present study used zebrafish as a model organism to investigate the effects of GAB on the early development of zebrafish and on its antioxidant system. Acute toxicity tests indicated that the 96 h LC50 value of GAB for zebrafish embryos was 59.9 g L-1. Further, it was observed that GAB causes malformation of embryos such as hemagglutination and pericardial edema. Compared to the control group, a significant enhancement (p < 0.05) of heartbeat rates was found at GAB concentrations exceeding 50 mg L-1, while the swimming frequency was clearly increased upon exposure to GAB at a concentration of 100 mg L-1 (p < 0.05). Additionally, the development of the zebrafish embryo was also negatively impacted after exposure to GAB as demonstrated by significantly decreased body lengths. Exposure to GAB at concentrations exceeding 50 mg L-1 significantly influenced the development of zebrafish, leading to malformation of organs and abnormal movements. Although no significant developmental effects of GAB were observed at environmentally relevant concentrations (0.1 and 10 μg L-1), further research about the antioxidant system confirmed that severe oxidant injury happened inside the organisms. catalase (CAT), lactate dehydrogenase (LDH), glutathione S-transferase (GST), glutathione (GSH) and the ability of inhibition of hydroxyl radicals (IHR) were used as biomarkers in the present study to illustrate GAB toxicity at environmentally relevant concentrations. The results showed that activities of CAT, LDH and GST as well as IHR were all elevated after GAB exposure, which proved that ROS were formed in the body as derived from GAB exposure. Among all of these biomarkers, CAT was the most sensitive one to evaluate the influence of GAB, and showed a significant increase even at a very low exposure concentration (0.1 μg L-1).

[Epidemiological features of prevalent influenza A viruses in children with influenza-like illness during the 2004-2017 season in Beijing]

Objective: To analyze and compare the epidemiological features of prevalent influenza A viruses in children in Beijing during 13 consecutive surveillance seasons from 2004 to 2017. Methods: This was a repeated cross section study. Throat swabs were collected weekly from children with influenza-like illnesses (ILI) who presented to the outpatient/emergency department of Children's Hospital, Capital Institute of Pediatrics during the period from September, 2004 to August, 2017. All of the specimens were inoculated into Madin Darby canine kidney (MDCK) cells to isolate influenza viruses followed by identifying different types of influenza viruses with reference antisera by hemagglutination-inhibition assay. Descriptive statistics, t test and chi-square test were used to analyze the characteristics of prevalent influenza and characteristics of children infected with different types of influenza viruses. Results: Out of 10 984 specimens from ILI tested for influenza viruses, 1 052 (9.6%) were positive for influenza A viruses, and the positive rate was higher than that of influenza B viruses (6.7%, 741/10 984). Out of 1 052 cases positive for influenza A viruses, 70 cases of seasonal H1N1, 302 cases of 2 009 pandemic H1N1 and 680 cases of H3N2 were identified. The mean age of children with influenza A was (4.2±2.9) years, in whom 55.5% (584/1 052) were male. The mean age of children infected with seasonal H1N1, 2009 pandemic H1N1 and H3N2 was (4.6±2.1) , (4.3±3.1) and (4.2±2.9) years, respectively. There was no significant difference in the mean age among children infected with different subtypes of influenza A viruses (seasonal H1N1 vs. H3N2: t=1.139, P=0.255; 2009 pandemic H1N1 vs. H3N2: t=0.631, P=0.528; seasonal H1N1 vs. 2009 pandemic H1N1: t=0.720, P=0.472), while the mean age of children with influenza B was higher than that of the patients with influenza A ((5.2±2.7) vs. (4.2±2.9) years, t=7.120, P=0.000). The infection rate of influenza A in children with each age group was significantly different from that of influenza B. The infection rate of 2009 pandemic H1N1 and H3N2 increased with age, except for the patients of 0-6 months. Meanwhile, the infection rate of H3N2 in children aged 6 months to 12 years was higher than that of seasonal H1N1 and 2009 pandemic H1N1 (all P<0.05). The influenza A epidemic peaked earlier than that of influenza B when the positive rate of influenza A was higher than that of influenza B, and vice versa. After 2009, circulating strain was substituted by 2009 pandemic H1N1 virus with higher positive rate, while previous seasonal H1N1 had not been detected. The 2009 pandemic H1N1 circulated at high level in two consecutive seasons, which was followed by low level in next season. H3N2 epidemic peaked mostly in winter and spring each year, however, the epidemic wave of H3N2 with high virulence occurred so early in the summer in the year of 2009 H1N1 pandemic. Conclusions: The characteristics of prevalent influenza A viruses in children were different among 13 surveillance seasons from 2004 to 2017 in Beijing. The 2009 pandemic H1N1 and H3N2 became the predominant strains of influenza A virus.

[Comprehensive treatment of 335 patients with pyriform sinus carcinoma by surgery via the paraglottic space approach]

Objective: To report the experience in comprehensive surgical treatment of pyriform sinus carcinoma via the paraglottic space approach. Methods: Three hundred and thirty-five cases with pyriform sinus carcinoma (according to UICC 2012 criteria, stage Ⅰ, 12 cases; Ⅱ, 36; Ⅲ, 79; Ⅳ, 208; T1, 26; T2, 139; T3, 121; T4, 49; cN0, 83; cN1, 61; cN2a-b, 118; cN2c, 71; cN3, 2) treated between 2006 and 2013 were retrospectively reviewed. There were 323 males and 12 females. Age aged from 36 to 80 years old with a median of 60 years old. There was no case with distant metastasis. All patients received modified neck dissection, including unilateral in 240 patients and bilateral in 95 patients. Pharyngoesophageal defects were reconstructed with directly suture in 246 cases, pectoralis major musculocutaneous flaps in 74 cases, and laryngotracheal flaps in 15 cases. Three hundred and nineteen patients received postoperative radiotherapy (55-65 Gy). Results: The overall 3 and 5 year survival rates were 68.6% (230/335) and 52.1%(139/267), respectively. The cervical lymph node metastases were found in 265 (79.1%) patients. Pathologic findings showed that all patients had squamous cell carcinoma. Laryngeal functions (voice, respiration and deglutition) were completely restored in 277 (82.7%) patients. Conclusions: The oncological efficacy of surgery via the paraglottic space approach is sure for pyriform sinus carcinoma, especially suitable for the early and medium-term lesions. The function of the larynx can retain after surgery, with the decreased incidences of cough and pharynx fistula.

A new locus regulating MICALL2 expression was identified for association with executive inhibition in children with attention deficit hyperactivity disorder

Impaired executive inhibition is a core deficit of attention deficit hyperactivity disorder (ADHD), which is a common childhood-onset psychiatric disorder with high heritability. In this study, we performed a two-stage genome-wide association study of executive inhibition in ADHD in Han Chinese. We used the Stroop color-word interference test to evaluate executive inhibition. After quality control, 780 samples with phenotype and covariate data were included in the discovery stage, whereas 922 samples were included in the replication stage. We identified one new significant locus at 7p22.3 for the Stroop word interference time (rs11514810, P=3.42E-09 for discovery, P=0.01176 for replication and combined P=5.249E-09). Regulatory feature analysis and expression quantitative trait loci (eQTL) data showed that this locus contributes to MICALL2 expression in the human brain. Most genes in the network interacting with MICALL2 were associated with psychiatric disorders. Furthermore, hyperactive-impulsive-like behavior was induced by reducing the expression of the zebrafish gene that is homologous to MICALL2, which could be rescued by tomoxetine (atomoxetine), a clinical medication for ADHD. Our results suggested that MICALL2 is a new susceptibility gene for executive inhibition deficiency related to hyperactive-impulsive behavior in ADHD, further emphasizing the possible role of neurodevelopmental genes in the pathogenic mechanism of ADHD.

Introduction to CAUSES: Description of Weather and Climate Models and Their Near-Surface Temperature Errors in 5 day Hindcasts Near the Southern Great Plains

We introduce the Clouds Above the United States and Errors at the Surface (CAUSES) project with its aim of better understanding the physical processes leading to warm screen temperature biases over the American Midwest in many numerical models. In this first of four companion papers, 11 different models, from nine institutes, perform a series of 5 day hindcasts, each initialized from reanalyses. After describing the common experimental protocol and detailing each model configuration, a gridded temperature data set is derived from observations and used to show that all the models have a warm bias over parts of the Midwest. Additionally, a strong diurnal cycle in the screen temperature bias is found in most models. In some models the bias is largest around midday, while in others it is largest during the night. At the Department of Energy Atmospheric Radiation Measurement Southern Great Plains (SGP) site, the model biases are shown to extend several kilometers into the atmosphere. Finally, to provide context for the companion papers, in which observations from the SGP site are used to evaluate the different processes contributing to errors there, it is shown that there are numerous locations across the Midwest where the diurnal cycle of the error is highly correlated with the diurnal cycle of the error at SGP. This suggests that conclusions drawn from detailed evaluation of models using instruments located at SGP will be representative of errors that are prevalent over a larger spatial scale.

Severe hepatitis treated with an artificial liver support system

We designed an artificial liver support system (ALSS) including plasma exchange, charcoal hemoperfusion, plasma bilirubin absorption, charcoal plasma perfusion, hemofiltration and hemodialysis. We chose different methods or their combinations according to the patients’ conditions. We investigated the effect of ALSS in 154 patients with severe hepatitis, 72 of whom survived. All data were analyzed by SPSS. The effectiveness of ALSS treatment was compared at different stages (i.e. early, middle and end stages). After each ALSS treatment, the liver function of these patients greatly improved, serum endotoxin and HBV-DNA concentrations were significantly decreased, and the serum concentration of aromatic amino acids (AAA) such as methionine decreased while BCAA/AAA ratio increased. Patients treated with ALSS in the early or middle stages of disease had much higher survival rates than patients in the end stage of disease. Thus, we concluded that ALSS is a reliable therapy for advanced liver diseases and treatment in early or middle stages is appropriate.

Toll-like receptor-4 regulates anxiety-like behavior and DARPP-32 phosphorylation

Toll-like receptors (TLRs) play a crucial role in early innate immune responses to inflammatory agents and pathogens. In the brain, some members of the TLR family are expressed in glial cells and neurons. In particular, TLR4 has been involved in learning and memory processes, stress-induced adaptations, and pathogenesis of neurodegenerative disorders. However, the role of TLR4 in emotional behaviors and their underlying mechanisms are poorly understood. In this study, we investigated the role of TLR4 in emotional and social behavior by using different behavioral approaches, and assessed potential molecular alterations in important brain areas involved in emotional responses. TLR4 knockout (KO) mice displayed increased anxiety-like behavior and reduced social interaction compared to wild type control mice. This behavioral phenotype was associated with an altered expression of genes known to be involved in emotional behavior [e.g., brain-derived neurotrophic factor (BDNF) and metabotropic glutamate receptors (mGluRs)]. Interestingly, the mRNA expression of dopamine- and cAMP-regulated phosphoprotein-32 (DARPP-32) was strongly upregulated in emotion-related regions of the brain in TLR4 KO mice. In addition, the phosphorylation levels at Thr75 and Ser97 in DARPP-32 were increased in the frontal cortex of TLR4 KO male mice. These findings indicate that TLR4 signaling is involved in emotional regulation through modulation of DARPP-32, which is a signaling hub that plays a critical role in the integration of numerous neurotransmitter systems, including dopamine and glutamate.

Abstract P6-08-04: National trends in mastectomy for operable breast cancers treated with neoadjuvant chemotherapy

Objective: Although neoadjuvant chemotherapy (NAC) has not been shown to improve survival compared with adjuvant therapy for patients with operable invasive breast cancer (IBC), it is often used to allow more limited surgery in the breast and axilla without compromising local control. We sought to evaluate national trends in mastectomy among patients with operable breast cancer treated with NAC and to characterize the contribution of demographic and tumor characteristics to changing trends.

Methods: We queried the National Cancer Database (NCDB) 2014 Participant User File for adult women who underwent surgery and received chemotherapy for unilateral T1-3N0-3M0 IBC diagnosed between 2010 and 2014. Surgery was classified as lumpectomy (BCS), unilateral mastectomy (UM) or bilateral mastectomy (BM). Molecular subtype was categorized according to ER, PR, and HER2 status. We used logistic regression to model surgery use (BM or UM vs BCS), adjusting for the following clinical covariates that were selected a priori: age, race/ethnicity, year of diagnosis, comorbidity score, metropolitan vs urban/rural residence, patient distance from treating facility, % with less than high school education (zip code based), insurance type, clinical stage, histology, and molecular subtype. As those who achieved pathologic complete response (pCR) after NAC should be ideal candidates for BCS, we also looked at this group separately. We then performed sensitivity analyses further controlling for region of the country and facility type, and for facility.

Results: We identified 235,339 patients who fulfilled our inclusion criteria. Of these patients, 25.3% were treated with NAC. Rates of pCR increased from 33.3% in 2010 to 46.3% in 2014 (p&lt;0.001). Rates of BCS increased from 37.0% in 2010 to 40.8% in 2014 (p&lt;0.001). While rates of UM decreased from 43.3% in 2010 to 34.7% in 2014 (p&lt;0.001), rates of BM with or without reconstruction increased from 19.7% in 2010 to 24.6% in 2014 (p&lt;0.001). Rates of BM without immediate reconstruction remained stable over time, from 11.8% in 2010 to 11.5% in 2014.

Among patients who received NAC, factors that were independently associated with both UM and BM (versus BCS) for both the entire cohort and those who achieved pCR included younger age, greater patient distance from facility, and higher clinical stage. Factors that were inversely associated with both UM and BM included black race and ductal histology. More recent year of diagnosis was inversely associated with UM and directly associated with BM. Asian race was associated with UM while non-Hispanic white race was associated with BM. Private or managed care insurance and higher area education were also associated with BM. These results were materially unchanged in sensitivity analyses.

Conclusion: Rates of pCR have increased over time among patients with operable IBC treated with NAC. While the rate of UM has declined over time, the rate of BM has increased. Significant sociodemographic differences exist between women who undergo BCS, and women who undergo UM and BM. Further study of factors that influence surgical decision-making in the NAC setting is warranted.

Citation Format: Pollom E, Qian Y, Dirbas F, Horst K, Tsai CJ. National trends in mastectomy for operable breast cancers treated with neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-04.

Abstract P4-04-04: Identification and development of oral estrogen receptor PROTAC degraders for breast cancer

ER-positive breast cancers comprise approximately 70-80% of all newly diagnosed cases. Downregulation or degradation of ER is a treatment approach currently used in the clinic to target estrogen receptor signaling. Faslodex, the only clinically-approved ER-downregulator, is administered as a monthly intramuscular injection with limiting pharmaceutical properties. Reasoning that an orally-available estrogen receptor degrader would be beneficial to patients, we have leveraged our experience in targeted protein degradation to generate and characterize novel proteolysis targeting chimeras (PROTACs) against estrogen receptor alpha. PROTACs are heterobifunctional molecules that facilitate the formation of a “trimer complex” comprised of the PROTAC, a pathogenic target protein of interest and an E3 ligase, which catalyzes the ubiquitylation and subsequent degradation of the target protein via the proteasome. To identify novel ER degraders (ER PROTACs), we have used several in vitro assays to characterize the extent of target engagement and receptor degradation. Potent ER PROTACs with good oral exposure and other pharmaceutical properties in multiple pre-clinical species were further evaluated in breast cancer xenograft models. Orally-administered ER PROTACs achieved &gt;80% degradation of estrogen receptor alpha and demonstrated single agent tumor growth inhibition in these disease models. Further, combination with a CDK4/6 inhibitor resulted in the expected improvement in anti-proliferative activity.

Citation Format: Flanagan JJ, Qian Y, Gough SM, Andreoli M, Bookbinder M, Bradley J, Rousseau E, Willard R, Crews CM, Crew AP, Taylor I, Houston J. Identification and development of oral estrogen receptor PROTAC degraders for breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-04-04.

BET protein proteolysis targeting chimera (PROTAC) exerts potent lethal activity against mantle cell lymphoma cells

Bromodomain extraterminal protein (BETP) inhibitors transcriptionally repress oncoproteins and nuclear factor-κB (NF-κB) target genes that undermines the growth and survival of mantle cell lymphoma (MCL) cells. However, BET bromodomain inhibitor (BETi) treatment causes accumulation of BETPs, associated with reversible binding and incomplete inhibition of BRD4 that potentially compromises the activity of BETi in MCL cells. Unlike BETi, BET-PROTACs (proteolysis-targeting chimera) ARV-825 and ARV-771 (Arvinas, Inc.) recruit and utilize an E3-ubiquitin ligase to effectively degrade BETPs in MCL cells. BET-PROTACs induce more apoptosis than BETi of MCL cells, including those resistant to ibrutinib. BET-PROTAC treatment induced more perturbations in the mRNA and protein expressions than BETi, with depletion of c-Myc, CDK4, cyclin D1 and the NF-κB transcriptional targets Bcl-xL, XIAP and BTK, while inducing the levels of HEXIM1, NOXA and CDKN1A/p21. Treatment with ARV-771, which possesses superior pharmacological properties compared with ARV-825, inhibited the in vivo growth and induced greater survival improvement than the BETi OTX015 of immune-depleted mice engrafted with MCL cells. Cotreatment of ARV-771 with ibrutinib or the BCL2 antagonist venetoclax or CDK4/6 inhibitor palbociclib synergistically induced apoptosis of MCL cells. These studies highlight promising and superior preclinical activity of BET-PROTAC than BETi, requiring further in vivo evaluation of BET-PROTAC as a therapy for ibrutinib-sensitive or -resistant MCL.

Individualized Survival and Treatment Response Predictions for Breast Cancers Using Phospho-EGFR, Phospho-ER, Phospho-HER2/neu, Phospho-IGF-IR/In, Phospho-MAPK, and Phospho-p70S6K Proteins

The development and progression of breast cancer involves the activation of numerous protein kinases, and the change in phosphorylation is a hallmark of protein kinase activation. In this study, we identified a comprehensive profile to predict individual breast cancer patients’ survival and treatment responses using the Random Committee algorithm. The profile incorporated a subset of phosphorylated signal protein expressions and several selected clinical factors of breast cancer. The parameters of our profile were identified by supervised feature selection algorithms, Gain Ratio Attribute Evaluation and Relief. The results showed that the overall accuracy of survival prediction reached 92.3% for individual breast cancer patients with the use of the expression profiles of phospho-EGFR, phospho-ER, phospho-HER2/neu, phospho-IGF-IR/In, phospho-MAPK, and phospho-p70S6K plus the selected clinical factors. The results also indicated that the overall accuracy of treatment response prediction was 92.6% with the use of the level of phospho-EGFR, phospho-ER, phospho-HER2/neu, phospho-MAPK, and phospho-p70S6K plus the selected clinical information. The prediction system combines multiple signal protein activation profiles and relevant clinical information, and provides a unique guideline to aid individualized decision-making in the clinical management of breast cancer.

Niacin ameliorates ulcerative colitis via prostaglandin D2-mediated D prostanoid receptor 1 activation

Niacin, as an antidyslipidemic drug, elicits a strong flushing response by release of prostaglandin (PG) D₂. However, whether niacin is beneficial for inflammatory bowel disease (IBD) remains unclear. Here, we observed niacin administration‐enhanced PGD₂ production in colon tissues in dextran sulfate sodium (DSS)‐challenged mice, and protected mice against DSS or 2,4,6‐trinitrobenzene sulfonic acid (TNBS)‐induced colitis in D prostanoid receptor 1 (DP1)‐dependent manner. Specific ablation of DP1 receptor in vascular endothelial cells, colonic epithelium, and myeloid cells augmented DSS/TNBS‐induced colitis in mice through increasing vascular permeability, promoting apoptosis of epithelial cells, and stimulating pro‐inflammatory cytokine secretion of macrophages, respectively. Niacin treatment improved vascular permeability, reduced apoptotic epithelial cells, promoted epithelial cell update, and suppressed pro‐inflammatory gene expression of macrophages. Moreover, treatment with niacin‐containing retention enema effectively promoted UC clinical remission and mucosal healing in patients with moderately active disease. Therefore, niacin displayed multiple beneficial effects on DSS/TNBS‐induced colitis in mice by activation of PGD₂/DP1 axis. The potential efficacy of niacin in management of IBD warrants further investigation.

[Homozygous ectonucleotide pyrophosphatase/phosphodiesterase 1 variants in a girl with hypophosphatemic rickets and literature review]

Objective: To investigate the clinical features and genetic characteristics of patients with ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene variants. Method: The clinical data of a patient with ENPP1 homozygous variants from Capital Institute of Pediatrics was collected, the related literature was searched from China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, National Center from Biotechnology Information and PubMed by using search term "ENPP1" , "hypophosphatemic rickets" . The literature retrieval was confined from 1980 to February 2017. The clinical manifestations, bone metabolism examinations, X-RAY and genotypes were reviewed. Result: Our patient was an 11 years old girl, with 7 years history of lower limb malformation. She showed significant valgus deformity of the knee (genu valgum). Metabolic examination revealed reduced level of plasma phosphate (0.86 mmol/L), a normal level of plasma calcium (2.30 mmol/L) and an elevated alkaline phosphatase level of 688 IU/L. The calcium-phosphorus product was 25.9. A homozygous nonsense variants of ENPP1 gene, c.783C>G (p.Tyr261X) in exon 7 was identified in the patient. Both parents were heterozygous carriers. Literature review identified 3 Chinese patients from one publication and 17 cases from twenty one publications around the world. None of the patients was found PHEX variants which is the most common variants among hypophosphatemic rickets patients. The disease onset age was 11 months to 10 years. Eight patients had short stature, five patients had the history of generalized arterial calcification of infancy. Four suffered from deafness, three showed localized calcifications of arteries, three patients manifested pseudoxanthoma elasticum and two suffered from ossification of posterior longitudinal ligament. Nine missense variants, six splicing variants and 4 nonsense variants were reported among these twenty patients. c.783C>G was found in two Chinese patients. Conclusion: ENPP1 gene mutation was a cause of patient with hypophosphatemic rickets. Comorbid features included generalized arterial calcification of infancy, early onset hearing loss, pseudoxanthoma and ossification of posterior longitudinal ligament. ENPP1 gene testing should be performed on hypophosphatemic rickets patients without PHEX gene variants. Long-term follow up is recommended. The most common types of ENPP1 gene variants were nonsense/splicing variants. The gene c.783C>G was the most common variants in Chinese patients.