SQSTM1/p62 is a prognostic molecular marker and potential therapeutic target for pancreatic neuroendocrine tumours.

BACKGROUND: There have been few studies on the role of autophagy in pancreatic neuroendocrine tumours (PNETs). SQSTM1/p62 (also called Sequestosome 1) is a potential autophagy regulator, and its biological roles and clinical significance in PNETs remain poorly understood. PURPOSE: The purpose of this study was to evaluate the clinical significance of SQSTM1/p62 in human PNET specimens and to evaluate its potential value as a therapeutic target by studying its biological function in PNET cell lines. METHODS: SQSTM1/p62 protein expression was assessed in 106 PNET patient specimens by immunohistochemistry, and the relationship between SQSTM1/p62 protein expression and the clinicopathological features of PNETs in patients was analysed. The proliferation, invasion and apoptosis of SQSTM1/p62-knockdown QGP-1 and INS-1 cells were assessed by the MTT assay, a Transwell assay and flow cytometry. Cell autophagy was assessed by western blotting and mCherry-GFP-LC3B. RESULTS: The protein expression of SQSTM1/p62 in PNET patient specimens was significantly correlated with tumour recurrence (p = 0.005) and worse prognosis (log rank p = 0.020). Downregulation of the SQSTM1/p62 gene inhibited tumour cell proliferation and migration and induced PNET cell death. Downregulation of SQSTM1/p62 activated autophagy in PNET cell lines but blocked autophagic flow. Knockdown of the SQSTM1/p62 gene inhibited mTOR phosphorylation. CONCLUSION: The SQSTM1/P62 protein could be an independent prognostic marker for PNET patients. Downregulating SQSTM1/P62 can inhibit PNET progression, inhibit mTOR phosphorylation and block autophagic flow.

Feasibility of standardized procedures of white light gastroscopy for clinical practice: A multicenter study in China.

OBJECTIVE: We aimed to establish a standardized procedure for white light gastroscopy (WLG) to screen gastric lesions including early gastric cancer (EGC) in China and to verify its efficacy and feasibility in clinical practice. METHODS: A standardized WLG procedure for outpatients at nine tertiary hospitals in Beijing was established. Clinical information of the participants and details of the endoscopic procedures were recorded. RESULTS: A total of 1051 participants were enrolled in a baseline conventional endoscopic survey between March 2014 and December 2015, while 2156 patients were enrolled in the standardized WLG operation from January 2016 to June 2017. The procedure time of the standardized procedure was significantly longer than that of the baseline conventional procedure (P = 0.003). More images were obtained during the standardized procedure compared with the baseline conventional procedure (P < 0.001). The overall detection rate of gastric lesions in the standardized procedure group was significantly higher than that in the baseline procedure group (52.5% vs 38.4%, P < 0.01). The satisfaction scores of both participants and endoscopists in the standardized procedure group were significantly higher than in the baseline procedure group. CONCLUSIONS: Compared with the conventional procedure, standardized WLG procedure significantly improves the detection rate of gastric lesions as well as the satisfaction score of participants and endoscopists despite its longer procedure time. It is effective and feasible in clinical practice in China for the use of currently available endoscopic equipment.

Degradation enhancement of rice straw by co-culture of Phanerochaete chrysosporium and Trichoderma viride.

Straw is one of the most abundant stock of renewable biomass from crop production. However, its utilization efficiency is still very low. Although co-cultivation of fungi increases the degrading rate, the co-cultivation condition needs to be optimized. To optimize the co-culture condition of Phanerochaete chrysosporium and Trichoderma viride degrading rice straw, we first tested the antagonistic characteristic between the fungi. The results showed that the best co-culture pattern was to first inoculate P. chrysosporium and culture for 4 days, then inoculate T. viride, and co-culture the two fungi for 4 days. The optimum fermentation condition was 14% (w/v) of inoculum concentration, the equivalent inoculation of the fungi, culture temperature at 30 °C, and 1:1.4 for solid-liquid ratio. Under the optimum condition, the degradation ratios of lignin and cellulose were 26.38% and 33.29%, respectively; the soluble carbon content in the culture product was 23.07% (w/v). The results would provide important reference information for the efficient utilization of rice straw to produce more accessible energy resources, such as ethanol and glucose.

CX-3543 Promotes Cell Apoptosis through Downregulation of CCAT1 in Colon Cancer Cells.

AIM: Colon cancer-associated transcript-1 (CCAT1), located in the vicinity of transcription factor c-Myc, was first identified in colon cancer. A small-molecule compound CX3543 (Quarfloxin) selectively targeting Myc G-quadruplexes has entered phase II clinical trials for neuroendocrine carcinomas. The aim of the study was to explore the relationship between CX3543, CCAT1, and cell apoptosis in colon cancer cells. METHODS: Semiquantitative PCR was used to detect the relative expression of CCAT1 in colon cancer (CC) tissues and HT29 cell lines. Real-time PCR (RT-PCR) was also used to investigate the expression of CCAT1 and c-Myc after HT29 cells being treated by CX3543 for 24 h. Cell apoptosis assay and cell proliferation assay were conducted in HT29 cells after being treated by CX3543. RESULTS: The results showed that the expression of CCAT1 was remarkably increased in CC tissues and HT29 cells compared to controls. CX3543 treatment reduced the expression of c-Myc and CCAT1 and promoted cell apoptosis and inhibited cell proliferation. After the expression of CCAT1 was inhibited by sh-CCAT1 transfection, the cell apoptosis rate was higher than that of control group. After the cells were treated by CCAT1 overexpression plasmid transfection and CX3543, the cell apoptosis rate was lower than that of control group. In vivo results showed that CX3543 inhibited the xenograft tumor growth of rats through downregulation of CCAT1. CONCLUSION: Our study demonstrated that CX3543 could inhibit the progression of colon cancer by downregulating CCAT1 expression and might be a potential drug for the treatment of colon cancer.

The complete mitochondrial genome of the hybrid of Ctenopharyngodon idella (♀) × Squaliobarbus curriculus (♂).

The complete mitochondrial genome sequence of the hybrid of Ctenopharyngodon idella (♀) × Squaliobarbus curriculus (♂) was determined using PCR-based method. The total length of the mitogenome is 16,609 bp. It contains the typical structure as that of most other vertebrates, including 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes, and 1 non-coding control region (D-loop region). The overall composition of the mitogenome was estimated to be 31.86% for A, 26.08% for T, 26.38% for C, and 15.68% for G, respectively, indicating that an A+T (57.94%)-rich feature occurs in the hybrid mitogenome. Both the termination-associated sequence and three conserved sequence blocks (CSB1, CSB2, and CSB3) were also detected in the D-loop region.

Mitochondrial DNA sequence of the hybrid of Squaliobarbus curriculus (♀) × Ctenopharyngodon idella (♂).

In this work, we reported the complete mitochondrial DNA sequence of the hybrid of Squaliobarbus curriculus (♀) × Ctenopharyngodon idella (♂), which was obtained by artificial hybridization. The total length of the mitochondrial genome is 16,616 bp, with the base composition of 31.15% A, 25.02% T, 27.66% C, and 16.17% G. It contains 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes, and a major non-coding control region (D-loop region). The arrangement of these genes is the same as that found in the teleosts. All the protein initiation codons are ATG, except for COX1 that begins with GTG. The complete mitogenome of the hybrid of S. curriculus (♀) × C. idella (♂) provides an important data set for the study in genetic mechanism.

Complete mitochondrial genome of the Xiangjiang barbel chub Squaliobarbus curriculus: comparative analysis of the genetic variation associated with geographical population.

The barbel chub (Squaliobarbus curriculus), a kind of small commercial fish, is widespread in China. In this study, we sequenced the mitochondrial genome of the barbel chub from the Xiangjiang River. The total length of the mitochondrial genome is 16,619 bp, with the base composition of 31.19% A, 25.01% T, 27.68% C, and 16.12% G. The organization and arrangement of these genes are the same as that found in the teleosts, including 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes, and a major noncoding control region (D-loop region). Compared with the S. curriculus collected from Jiangsu province, there were 29 mutation sites in the mitogenome sequence of Xiangjiang S. curriculus. All the mutation sites were transitions and mainly occurred in protein-coding genes (21/29), two mutation sites occurred in transfer RNA, two occurred in ribosomal RNA, and four occurred in D-loop region. Among the 21 mutation sites in protein-coding genes, 6 mutation sites resulted in amino acid mutation in ND2, ATPase6, COX3, ND4, and Cytb genes, while the others were synonymous substitutions. These results indicated that there was genetic variation in different geographical populations of S. curriculus.

Functional evolution of leptin of Ochotona curzoniae in adaptive thermogenesis driven by cold environmental stress.

BACKGROUND: Environmental stress can accelerate the directional selection and evolutionary rate of specific stress-response proteins to bring about new or altered functions, enhancing an organism's fitness to challenging environments. Plateau pika (Ochotona curzoniae), an endemic and keystone species on Qinghai-Tibetan Plateau, is a high hypoxia and low temperature tolerant mammal with high resting metabolic rate and non-shivering thermogenesis to cope in this harsh plateau environment. Leptin is a key hormone related to how these animals regulate energy homeostasis. Previous molecular evolutionary analysis helped to generate the hypothesis that adaptive evolution of plateau pika leptin may be driven by cold stress. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis, recombinant pika leptin was first purified. The thermogenic characteristics of C57BL/6J mice injected with pika leptin under warm (23±1°C) and cold (5±1°C) acclimation is investigated. Expression levels of genes regulating adaptive thermogenesis in brown adipose tissue and the hypothalamus are compared between pika leptin and human leptin treatment, suggesting that pika leptin has adaptively and functionally evolved. Our results show that pika leptin regulates energy homeostasis via reduced food intake and increased energy expenditure under both warm and cold conditions. Compared with human leptin, pika leptin demonstrates a superior induced capacity for adaptive thermogenesis, which is reflected in a more enhanced ß-oxidation, mitochondrial biogenesis and heat production. Moreover, leptin treatment combined with cold stimulation has a significant synergistic effect on adaptive thermogenesis, more so than is observed with a single cold exposure or single leptin treatment. CONCLUSIONS/SIGNIFICANCE: These findings support the hypothesis that cold stress has driven the functional evolution of plateau pika leptin as an ecological adaptation to the Qinghai-Tibetan Plateau.

Natural selection and adaptive evolution of leptin in the ochotona family driven by the cold environmental stress.

BACKGROUND: Environmental stress can accelerate the evolutionary rate of specific stress-response proteins and create new functions specialized for different environments, enhancing an organism's fitness to stressful environments. Pikas (order Lagomorpha), endemic, non-hibernating mammals in the modern Holarctic Region, live in cold regions at either high altitudes or high latitudes and have a maximum distribution of species diversification confined to the Qinghai-Tibet Plateau. Variations in energy metabolism are remarkable for them living in cold environments. Leptin, an adipocyte-derived hormone, plays important roles in energy homeostasis. METHODOLOGY/PRINCIPAL FINDINGS: To examine the extent of leptin variations within the Ochotona family, we cloned the entire coding sequence of pika leptin from 6 species in two regions (Qinghai-Tibet Plateau and Inner Mongolia steppe in China) and the leptin sequences of plateau pikas (O. curzonia) from different altitudes on Qinghai-Tibet Plateau. We carried out both DNA and amino acid sequence analyses in molecular evolution and compared modeled spatial structures. Our results show that positive selection (PS) acts on pika leptin, while nine PS sites located within the functionally significant segment 85-119 of leptin and one unique motif appeared only in pika lineages-the ATP synthase alpha and beta subunit signature site. To reveal the environmental factors affecting sequence evolution of pika leptin, relative rate test was performed in pikas from different altitudes. Stepwise multiple regression shows that temperature is significantly and negatively correlated with the rates of non-synonymous substitution (Ka) and amino acid substitution (Aa), whereas altitude does not significantly affect synonymous substitution (Ks), Ka and Aa. CONCLUSIONS/SIGNIFICANCE: Our findings support the viewpoint that adaptive evolution may occur in pika leptin, which may play important roles in pikas' ecological adaptation to extreme environmental stress. We speculate that cold, and probably not hypoxia, may be the primary environmental factor for driving adaptive evolution of pika leptin.