Novel multiplex stool-based assay for the detection of early-stage colon cancer in a Chinese population.

BACKGROUND: Stool DNA (sDNA) methylation analysis is a promising, noninvasive approach for colorectal cancer screening; however, reliable biomarkers for detecting early-stage colon cancer (ECC) are lacking, particularly in the Chinese population. AIM: To identify a novel stool-based assay that can improve the effectiveness of ECC screening. METHODS: A blinded case-control study was performed using archived stool samples from 125 ECC patients, and 125 control subjects with normal colonoscopy. The cohort was randomly divided into training and test sets at a 1.5:1 ratio. Targeted bisulfite sequencing (TBSeq) was conducted on five pairs of preoperative and postop-erative sDNA samples from ECC patients to identify DNA methylation biomarkers, which were validated using pyrosequencing. By logistic regression analysis, a multiplex stool-based assay was developed in the training set, and the detection performance was further assessed in the test set and combined set. The χ 2 test was used to investigate the association of detection sensitivity with clinico-pathological features. RESULTS: Following TBSeq, three hypermethylated cytosine-guanine sites were selected as biomarkers, including paired box 8, Ras-association domain family 1 and secreted frizzled-related protein 2, which differed between the groups and were involved in important cancer pathways. An sDNA panel containing the three biomarkers was constructed with a logistic model. Receiver operating characteristic (ROC) analysis revealed that this panel was superior to the fecal immunochemical test (FIT) or serum carcinoembryonic antigen for the detection of ECC. We further found that the combination of the sDNA panel with FIT could improve the screening effectiveness. In the combined set, the sensitivity, specificity and area under the ROC curve for this multiplex assay were 80.0%, 93.6% and 0.918, respectively, and the performance remained excellent in the subgroup analysis by tumor stage. In addition, the detection sensitivity did not differ with tumor site, tumor stage, histological differentiation, age or sex, but was significantly higher in T4 than in T1-3 stage tumors (P = 0.041). CONCLUSION: We identified a novel multiplex stool-based assay combining sDNA methylation biomarkers and FIT, which could detect ECC with high sensitivity and specificity throughout the colon, showing a promising application perspective.

New Cyclohexadepsipeptides from an Entomogenous Fungus Fusarium proliferatum and Their Cytotoxicity and Autophagy-Inducing Activity.

Five new cyclohexadepsipeptides termed as enniatins R - V (1 - 5) and seven known cyclohexadepsipeptides (6 - 12) were isolated from the solid culture of Fusarium proliferatum, a fungus isolated from the cadaver of an unidentified insect collected in Tibet. Their structures were elucidated by NMR and MS spectroscopic analysis. The X-ray single-crystal structure of 6 was reported for the first time. Enniatins R and S represented the first enniatins incorporating with an unusual 2,3-dihydroxy-isovaleric acid (Div) residue. The cytotoxicity and autophagy-inducing activities of 1 - 12 were evaluated in vitro. Beauvenniatin F (11) exhibited strong cytotoxicity against K562/A (adriamycin-resistant K562) with IC50 value of 3.78 µm, and also autophagy-inducing activity at the concentration of 20 µm in GFP-LC3 stable HeLa cells.

Stucturally Diverse Sesquiterpenes Produced by a Chinese Tibet Fungus Stereum hirsutum and Their Cytotoxic and Immunosuppressant Activities.

Two new heterodimeric sesquiterpenes, sterhirsutins C (1) and D (2), along with eight new sesquiterpenoid derivatives, sterhirsutins E--L (3-10), were isolated from the culture of Stereum hirsutum. The absolute configuration of 1 was assigned by a single-crystal X-ray diffraction experiment. Compounds 1 and 2 possessed an unprecedented chemical skeleton with a 5/5/5/6/9/4 fused ring system. Compound 10 is the first sesquiterpene coupled with a xanthine moiety. Compounds 1-10 showed cytotoxicity against K562 and HCT116 cell lines. Compound 9 induced autophagy in HeLa cells. Compound 5 inhibited the activation of IFNß promoter in Sendai virus infected cells.

Cochlioquinone derivatives with apoptosis-inducing effects on HCT116 colon cancer cells from the phytopathogenic fungus Bipolaris luttrellii L439.

A new cochlioquinone derivative, cochlioquinone F (1), as well as three known compounds, anhydrocochlioquinone A (2), isocochlioquinone A (3), and isocochlioquinone C (4), were isolated from the PDB (potato dextrose broth) culture of the phytopathogenic fungus Bipolaris luttrellii. The structure of 1 was elucidated on the basis of NMR techniques. The apoptosis-inducing effects of compounds 1-4 were evaluated against HCT116 cancer cells. Compound 2 exhibited the strongest activity in inducing apoptosis on HCT116 cells within the range of 10-30 µM. In addition, the caspase activation, the release of cytochrome c from mitochondria, and the downregulation of Bcl-2 protein in HCT116 cells treated with compound 2 were detected.

Phaeolschidins A-E, five hispidin derivatives with antioxidant activity from the fruiting body of Phaeolus schweinitzii collected in the Tibetan Plateau.

Five new hispidin derivatives, phaeolschidins A-E (1-5), as well as two known natural products, pinillidine (6) and hispidin (7), were isolated from the fruiting bodies of Phaeolus schweinitzii collected in the Tibetan Plateau. The structures of the new compounds were elucidated by spectroscopic methods. Phaeolschidins A-D (1-4) are new bishispidins. Phaeolschidin E (5) is a new class of hispidin derivative in which one pyrrolidin-2-one moiety was linked to C-3 of hispidin. The antioxidant activity of 1-7 was evaluated using three methods: the DPPH scavenging assay, the total antioxidant capacity assay, and the lipid peroxidation assay. Hispidin showed the strongest antioxidant activity of all tested compounds. This is the first report of secondary metabolites from the fungus P. schweinitzii.