Squalene synthase predicts poor prognosis in stage I-III colon adenocarcinoma and synergizes squalene epoxidase to promote tumor progression.

Colon adenocarcinoma (COAD) is one of the most prevalent malignancies, with poor prognosis and lack of effective treatment targets. Squalene synthase (FDFT1) is an upstream enzyme of squalene epoxidase (SQLE) in cholesterol biosynthesis. In a previous study, we revealed that SQLE promotes colon cancer cell proliferation in vitro and in vivo. Here, we investigate the prognostic value of FDFT1 in stage I-III COAD and explore the potential underlying mechanisms. Squalene synthase was significantly upregulated in stage I-III COAD and positively correlated with poor differentiation and advanced tumor stage. High expression of FDFT1 was an independent predictor of overall and relapse-free survival, and the nomograms based on FDFT1 could effectively identify patients at high risk of poor outcome. Squalene synthase accelerated colon cancer cell proliferation and promoted tumor growth. Lack of FDFT1 resulted in accumulating NAT8 and D-pantethine to lower reactive oxygen species levels and inhibit colon cancer cell proliferation. Moreover, the combined inhibition of FDFT1 and SQLE induced a greater suppressive effect on cell proliferation and tumor growth than single inhibition. Taken together, these results indicate that FDFT1 predicts poor prognosis in stage I-III COAD and has the tumor-promoting effect on COAD through regulating NAT8 and D-pantethine. Targeting both FDFT1 and SQLE is a more promising therapy than their single inhibition for stage I-III COAD.

A New Fungal Diterpene Induces VDAC1-dependent Apoptosis in Bax/Bak-deficient Cells.

The pro-apoptotic Bax and Bak proteins are considered central to apoptosis, yet apoptosis occurs in their absence. Here, we asked whether the mitochondrial protein VDAC1 mediates apoptosis independently of Bax/Bak. Upon screening a fungal secondary metabolite library for compounds inducing apoptosis in Bax/Bak-deficient mouse embryonic fibroblasts, we identified cyathin-R, a new cyathane diterpenoid compound able to activate apoptosis in the absence of Bax/Bak via promotion of the VDAC1 oligomerization that mediates cytochrome c release. Diphenylamine-2-carboxilic acid, an inhibitor of VDAC1 conductance and oligomerization, inhibited cyathin-R-induced VDAC1 oligomerization and apoptosis. Similarly, Bcl-2 overexpression conferred resistance to cyathin-R-induced apoptosis and VDAC1 oligomerization. Silencing of VDAC1 expression prevented cyathin-R-induced apoptosis. Finally, cyathin-R effectively attenuated tumor growth and induced apoptosis in Bax/Bak-deficient cells implanted into a xenograft mouse model. Hence, this study identified a new compound promoting VDAC1-dependent apoptosis as a potential therapeutic option for cancerous cells lacking or presenting inactivated Bax/Bak.

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.

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.

Collagen I-induced VCAN/ERK signaling and PARP1/ZEB1-mediated metastasis facilitate OSBPL2 defect to promote colorectal cancer progression.

The global burden of colorectal cancer (CRC) has rapidly increased in recent years. Dysregulated cholesterol homeostasis facilitated by extracellular matrix (ECM) remodeling transforms the tumor microenvironment. Collagen I, a major with ECM component is highly expressed in colorectal tumors with infiltrative growth. Although oxysterol binding protein (OSBP)-related proteins accommodate tumorigenesis, OSBPL2, which is usually involved in deafness, is not associated with CRC progression. Therefore, we aimed to investigate the pathological function of OSBPL2 and identify the molecular link between ECM-Collagen I and OSBPL2 in CRC to facilitate the development of new treatments for CRC. OSBPL2 predicted a favorable prognosis in stage IV CRC and substantially repressed Collagen I-induced focal adhesion, migration, and invasion. The reduction of OSBPL2 activated ERK signaling through the VCAN/AREG/EREG axis during CRC growth, while relying on PARP1 via ZEB1 in CRC metastasis. OSBPL2 defect supported colorectal tumor growth and metastasis, which were suppressed by the ERK and PARP1 inhibitors SCH772984 and AG14361, respectively. Overall, our findings revealed that the Collagen I-induced loss of OSBPL2 aggravates CRC progression through VCAN-mediated ERK signaling and the PARP1/ZEB1 axis. This demonstrates that SCH772984 and AG14361 are reciprocally connective therapies for OSBPL2Low CRC, which could contribute to further development of targeted CRC treatment.

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.

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.

Squalene epoxidase promotes colorectal cancer cell proliferation through accumulating calcitriol and activating CYP24A1-mediated MAPK signaling.

BACKGROUND: Colorectal cancer (CRC) is one of the most malignant tumors with high incidence, yet its molecular mechanism is not fully understood, hindering the development of targeted therapy. Metabolic abnormalities are a hallmark of cancer. Targeting dysregulated metabolic features has become an important direction for modern anticancer therapy. In this study, we aimed to identify a new metabolic enzyme that promotes proliferation of CRC and to examine the related molecular mechanisms. METHODS: We performed RNA sequencing and tissue microarray analyses of human CRC samples to identify new genes involved in CRC. Squalene epoxidase (SQLE) was identified to be highly upregulated in CRC patients. The regulatory function of SQLE in CRC progression and the therapeutic effect of SQLE inhibitors were determined by measuring CRC cell viability, colony and organoid formation, intracellular cholesterol concentration and xenograft tumor growth. The molecular mechanism of SQLE function was explored by combining transcriptome and untargeted metabolomics analysis. Western blotting and real-time PCR were used to assess MAPK signaling activation by SQLE. RESULTS: SQLE-related control of cholesterol biosynthesis was highly upregulated in CRC patients and associated with poor prognosis. SQLE promoted CRC growth in vitro and in vivo. Inhibition of SQLE reduced the levels of calcitriol (active form of vitamin D3) and CYP24A1, followed by an increase in intracellular Ca2+ concentration. Subsequently, MAPK signaling was suppressed, resulting in the inhibition of CRC cell growth. Consistently, terbinafine, an SQLE inhibitor, suppressed CRC cell proliferation and organoid and xenograft tumor growth. CONCLUSIONS: Our findings demonstrate that SQLE promotes CRC through the accumulation of calcitriol and stimulation of CYP24A1-mediated MAPK signaling, highlighting SQLE as a potential therapeutic target for CRC treatment.

Strategic communication related to academic performance: Evidence from China.

We examined a range of forms of strategic communication relevant to academic performance among 151 seventh- and eleventh-grade adolescents in China. Participants were asked to rate the frequency of their engagement of strategic communication and to evaluate the possible motives for each strategy. The most commonly adopted strategy was to give a vague response about one's own performance, and the predominant motives for strategic communication were the desires to outcompete others, to be prosocial, and to be modest. Males were more likely than females to focus on gaining social approval, and eleventh graders were more likely than seventh graders to focus on being prosocial and modest when engaging in strategic communication. These findings provide insight into the development of strategic communication beyond Western culture. Statement of contribution What is already known on this subject? Adolescents in the West often hide their effort to appear more competent or to gain social acceptance. Little is known about other communication strategies related to academic performance. Little is known about the development of these strategies in non-Western samples. What does this study add? We show that in China, as in Western cultures, children often engage in strategic communication. We demonstrate links between different forms of strategic communication and specific motives. We demonstrate that strategic communication can be motivated by outcompeting others, by being prosocial, and by being modest.

Versicoamides F-H, Prenylated Indole Alkaloids from Aspergillus tennesseensis.

Three highly modified indole alkaloids, versicoamides F-H (1-3), together with seven known alkaloids (4-10) were isolated from the fungus Aspergillus tennesseensis. The structures of new compounds were determined by analysis of the NMR and MS spectroscopic data. The absolute configurations of 1 and 2 were assigned by single-crystal X-ray diffraction experiments. Compounds 1 and 2 showed weak antiproliferative activity against the H460 cell line. Compounds 1-3 represent a new class of natural product hybrids with new chemical skeletons.

Identification of a new cyathane diterpene that induces mitochondrial and autophagy-dependent apoptosis and shows a potent in vivo anti-colorectal cancer activity.

Diterpenes has been reported to possess multiple bioactivities consisting of anti-microbial and anti-inflammatory properties. This study reveals a new cyathane-type diterpene (cyathin Q) from the culture of the fungus Cyathus africanus by bioactivity-guided separation. The structure of cyathin Q was determined based on spectroscopic measurements (NMR and MS). The bioactivity evaluation shows that cyathin Q has a strong anticancer activity against HCT116 cells and Bax-deficient HCT116 in vitro and in vivo. This compound induced hallmarks of apoptotic events in HCT116 cells, including caspase activation, cytochrome c release, poly (ADP-ribose) polymerase (PARP) cleavage, and depolarization of the mitochondrial inner transmembrane potential. This process is accompanied with the increased mitochondrial ROS, down-regulation of Bcl-2 protein, and up-regulation of Bim protein. We also observed the cleavage of autophagy-related protein ATG5 in cyathin Q-induced apoptosis. Taken together, our study identified a new fungal diterpene that exhibited anticancer activity via induction of mitochondria and autophagy-dependent apoptosis in HCT116 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.

Redox heme-proteins mediated fluorescence of CdSe/ZnS quantum dots.

The redox properties of cytochrome c (Cyt c), hemoglobin (Hb) and myoglobin (Mb) were studied based on electrostatic interactions between Thioglycolic acid (TGA) capped CdSe/ZnS quantum dots (QDs) and proteins. Results indicated that only Cyt c quenched the fluorescence of the QDs at pH>8.0. Under the optimized conditions, a significant fluorescence recovery of the QDs' system was observed when the reduced form of Cyt c incubated with TGA capped QDs, however, the reduced state of Hb and Mb resulted in a more fluorescence quenching on the same size of QDs. Interestingly, the fluorescence changes of QDs-proteins could be switched by modulating the redox potentials of proteins-attached QDs. Moreover, only the oxidized Cyt c form was reduced by the generated O2(-) that significantly enhanced the fluorescence of the QDs' system, which was also demonstrated by fluorescence imaging in HeLa cells.