Discovery of Oxidized Polycyclic Tetramate Macrolactams Bearing One or Two Rings through Combinatorial Pathway Reassembly

The structural diversity of polycyclic tetramate macrolactams (PoTeMs) are mainly generated by the cyclases and cytochrome P450s (CYPs). The PoTeM cluster sah in Saccharopolyspora hirsuta harboring two CYP genes was combinatorially reassembled and heterologously expressed in Streptomyces. As a result, six new cytotoxic PoTeMs, sahamides A-F (1-6), were discovered, and 1-3 are the first examples of oxidized one-ring PoTeMs. Remarkably, SahE represents the first CYP performing oxidative modification on the ornithine moiety of PoTeMs.

Biosynthesis of Glidomides and Elucidation of Different Mechanisms for Formation of β-OH Amino Acid Building Blocks

Nonribosomal peptide synthetases (NRPSs) can incorporate nonproteinogenic amino acids into peptidyl backbones to increase structural diversity. Genome mining of Schlegelella brevitalea led to the identification of a class of linear lipoheptapeptides, glidomides, featuring two unusual residues: threo-β-OH-L-His and threo-β-OH-D-Asp. The β-hydroxylation of Asp and His is catalyzed by the nonheme Fe^II /α-ketoglutarate-dependent β-hydroxylases GlmD and GlmF, respectively. GlmD independently catalyzes the hydroxylation of L-Asp to primarily produce threo-β-OH-L-Asp on the thiolation domain, and then undergoes epimerization to form threo-β-OH-D-Asp in the final products. However, β-hydroxylation of His requires the concerted action of GlmF and the interface (I) domain, a novel condensation domain family clade. The key sites of I domain for interaction with GlmF were identified, suggesting that the mechanism for hydroxylation of His depends on the collaboration between hydroxylase and NRPS.

Discovery of N-arylcinnamamides as novel erythroblast enucleation inducers

Derivation of mature red blood cells (RBCs) from stem cells in vitro is a promising solution to the current shortage of blood supply, in which terminal enucleation is the rate-limiting step. Here we discovered two cinnamamides B8 and B16 showed potential activities of enhancing the enucleation of erythroblasts through the screening of "in-house" compound library. Subsequently, twenty-four N-arylcinnamamides were rationally designed and synthesized on the basis of the structure of B8 and B16, in which N-(9H-carbazol-2-yl)cinnamamide (KS-2) significantly elevated the percentage of reticulocytes in the cultured mouse fetal liver cells in vitro (relative enucleation = 2.43). The underlying mechanism of KS-2 in promoting mouse erythroid enucleation is accelerating the process of cell cycle exit via p53 activation in late stage erythrocytes. These results strongly suggest that compound KS-2 is worthy of further study as a potential erythrocyte enucleation inducer.

[High expression of MYBL2 promotes progression and predicts a poor survival outcome of prostate cancer]

OBJECTIVE

To explore the correlation of MYB proto-oncogene like 2 (MYBL2) with biological behaviors and clinical prognosis of prostate cancer (PCa).

METHODS

We detected Mybl2 mRNA expression in 45 pairs of PCa and adjacent tissues using real-time quantitative PCR, and analyzed the correlation of high (23 cases) and low expression (22 cases) of Mybl2 with clinicopathological features and prognosis of the patients using nonparametric test, Kaplan-Meier survival analysis and univariate and multivariate Cox regression. The results were verified by analysis of the data from Cancer Genome Atlas (TCGA) microarray database, and the molecular pathways were identified by gene set enrichment analysis (GSEA). The CIBERPORT algorithm was used to identify the correlations between Mybl2 expression and tumor microenvironment of PCa. We also tested the effects of MYBL2 knockdown on proliferation and invasion of PCa cell lines using cell counting kit-8 and Transwell assays and observed the growth of PC3 cell xenograft with MYBL2 knockdown in nude mice and the expression levels of Ki-67 in the xenograft using immunohistochemistry.

RESULTS

Mybl2 expression was significantly elevated in PCa tissues in close correlation with Gleason score and clinical and pathological stage of the tumor (P < 0.01) but not with the patients' age. Kaplan-Meier analysis indicated a significant negative correlation of high Mybl2 expression with recurrence-free survival (P < 0.05), but not with the overall survival of the patients. The data from TCGA suggested that clinical and pathological stages were independent prognostic factors for recurrence-free survival, and our data indicated that clinical stage and Gleason score were independent prognostic factors of PCa (P < 0.05). GSEA suggested that Mybl2 expression was related with the pathways involving immune function, cell adhesion, and cytokine secretion; CIBERPORT analysis suggested the involvement of Mybl2 expression with memory B cells and resting mast cells (P < 0.05). In LNCaP and PC-3 cells, MYBL2 knockdown significantly inhibited cell proliferation and invasion (P < 0.05); in the tumor-bearing nude mice, the xenografts derived from PC-3 cells with MYBL2 knockdown exhibited a lowered mean tumor weight and positivity rate for Ki67 (P < 0.05).

CONCLUSION

Mybl2 is an oncogene related with multiple pathological indicators of PCa and can serve as a potential prognostic marker as well as a therapeutic target for patients with PCa.

Effect of arginine supplementation on the production of milk fat in dairy cows

Arginine, one of the conditionally essential AA, has been reported to affect fat synthesis and metabolism in nonruminant animals by influencing adenosine monophosphate activated protein kinase (AMPK) in some organs. In dairy cows, the effect of Arg on milk fat production is not clear, and any potential mechanism that underlies the effect is unknown. We tested the hypothesis that Arg infusion would improve the production of milk fat, and explored possible mechanism that might underlie any effect. We used 6 healthy lactating cows at 20 ± 2 d in milk, in fourth parity, with a body weight of 508 ± 14 kg, body condition score of 3.0 ± 0, and a milk yield of 30.6 ± 1.8 kg/d (mean ± standard deviation). The cows were blocked by days in milk and milk yield and each cow received 3 treatments in a replicated 3 × 3 Latin square design, with each of the experimental periods lasting 7 d with a 14-d washout between each period. The treatments, delivered in random order, were (1) infusion of saline (control); (2) infusion of 0.216 mol/d of l-Arg in saline (Arg); (3) infusion of 0.868 mol/d of l-Ala in saline (the Arg and Ala treatments were iso-nitrogenous) through a jugular vein. On the last day of each experimental period, blood was sampled to measure insulin, nitric oxide, glucose, and nonesterified fatty acid, and the liver and mammary gland were biopsied to measure the expression of genes. Milk yield was recorded, and milk fat percentage was measured daily during each of the experimental periods. The yield and composition of fatty acid (FA) in milk was measured daily on the last 3 d during each of the experimental periods. The data were analyzed using a mixed model with treatment as a fixed factor, and cow, period, and block as random factors. The daily milk yield and milk fat yield when the cows were infused with Arg were 2.2 kg and 76 g, respectively, higher than that in control, and 1.8 kg and 111 g, respectively, higher than that in Ala. When the cows were infused with Arg they had higher concentration and yield of de novo synthesized FA, than when they received the control or Ala infusions, although milk fat percentage, daily feed intake, and the digestibility of nutrients were not affected by treatment. The serum concentration of nitric oxide and insulin were higher during Arg than during control or Ala, with no difference between control and Ala. In the liver, the expression of the genes coding for AMPK (PRKAA1, PRKAB1, and PRKAG1) and genes related to the oxidation of FA were higher during Arg than during control or Ala, whereas in the mammary gland the expression PRKAB1 was lowest, and the expression of genes involved in the synthesis of milk fat were highest, during Arg infusion. The results suggest the intravenous infusion of Arg enhanced the production of milk fat by promoting the de novo synthesis of FA and increasing milk yield.

Comparison of outcomes of ventral hernia repair using different meshes: a systematic review and network meta-analysis

PURPOSE

We conducted a network meta-analysis to evaluate potential differences in patient outcomes when different meshes, especially biological meshes, were used for ventral hernia repair.

METHODS

PubMed, Embase, Cochrane Library, and Clinical Trials.gov databases were searched for studies comparing biological meshes with biological or synthetic meshes for ventral hernia repair. The outcomes were hernia recurrence rate, surgical site infection, and seroma. We performed a two-step network meta-analysis to investigate the outcomes of several biological meshes: non-cross-linked human acellular dermal matrix (NCHADM), non-cross-linked porcine ADM (NCPADM), non-cross-linked bovine ADM (NCBADM), cross-linked porcine ADM (CPADM), and porcine small intestinal submucosa (PSIS).

RESULTS

From 6304 publications, 23 studies involving 2603 patients were finally included. We found no differences between meshes in recurrence at 1-year follow-up and in surgical site infection rate. NCBADM was associated with the lowest recurrence rate and the lowest surgical site infection rate. NCHADM implantation was associated with the lowest rate of seroma. PSIS was associated with a higher risk of seroma than NCHADM (pooled risk ratio 3.89, 95% confidence interval 1.13-13.39) and NCPADM (RR 3.42, 95% CI 1.29-9.06).

CONCLUSIONS

Our network meta-analysis found no differences in recurrence rate or surgical site infection among different biological meshes. The incidence of postoperative seroma was higher with PSIS than with acellular dermal matrices. We observed large heterogeneity in the studies of ventral hernia repair using biological meshes, and, therefore, well-designed randomized clinical trials are needed.

[Application of multiple post labeling delay time arterial spin labeling imaging in the quantitative blood flow analysis of brain subregions in healthy adults]

Objective: To explore the normal ranges of perfusion parameters between cerebral hemisphere, cerebellar hemisphere and brain anatomical subregions (56 pairs) in different gender and age groups with multiple post labeling delay time (Multi-PLD) arterial spin labeling (ASL) imaging. Methods: From November 2020 to December 2020, 42 healthy adult volunteers (Male 25, Female 17) were recruited to perform 7 PLD ASL imaging, including 21 young adults (15 males and 6 females, aged 23-35 years) and 21 seniors (10 males and 11 females, aged 36-74 years). The data was processed offline by Cereflow software to obtain arterial arrival time (ATT) and corrected cerebral blood flow (CBF) and cerebral blood volume (CBV) perfusion parameters. SimpleITK standardization function was used to standardize the calculated perfusion image according to the anatomical automatic labeling (AAL) template. Therefore, CBF, ATT, CBV perfusion values of brain subregions were obtained. Paired samples t test, Wilcoxon rank sum test, independent samples t test and Mann-Whitney U test were used to compare the differences of perfusion parameters in the cerebral hemisphere, the cerebellar hemisphere, brain subregions depending on side, gender and age. Pearson correlation analysis was used to compare the correlations of perfusion parameters with age. Results: CBF in 62.5% (35/56) subregions and CBV in 44.6% (25/56) subregions were higher in right side than those in left side. ATT in most brain anatomical subregions (16/56) were higher in left side. The CBF [(35.30±8.31) vs. (34.34±7.53) ml·100g^-1·min^-1, P=0.021], CBV [(0.47±0.11) vs. (0.45±0.09) ml/100g, P<0.001], ATT [(1.30±0.10) vs. (1.24±0.11) s, P<0.001] in left cerebellar hemisphere were higher than that of right side. The CBF (28/56) of cerebral hemisphere, cerebellar hemisphere and brain subregions was higher in females than that in males, while ATT in 83.9% (47/56) subregions was lower than that in males (all P<0.05). CBV in female subjects was higher only in 5 brain regions (superior occipital gyrus, middle occipital gyrus, inferior occipital gyrus, superior parietal gyrus and cerebelum_7b) (all P<0.05). In young subjects, CBF in 44.6% (25/56) subregions and CBV in 33.9% (19/56) subregions were higher than those in the senior group (all P<0.05). The ATT in most subregions in young group were lower than those in senior group, but the difference was statistically significant only in rectus gyrus (P=0.026) and paracentral lobule (P=0.006). The CBF (r=-0.430, P=0.005) and CBV (r=-0.327, P=0.035) of cerebral hemisphere were negatively correlated with age. The CBF (24/25, r range:-0.497 --0.343, all P<0.05) and CBV (16/19, r range:-0.474 --0.322, all P<0.05) in most subregions were negatively correlated with age, while ATT was positively correlated (gyrus rectus: r=0.311, P=0.045; paracentral lobule: r=0.392, P=0.010). Conclusions: Multi-PLD ASL imaging could be applied for quantitative analysis of brain perfusion. The perfusion parameters of anatomical subregions are different depending on side, gender, and age.

Potential biomarkers in the fibrosis progression of nonalcoholic steatohepatitis (NASH)

PURPOSE

Fibrosis is the only histological feature reflecting the severity and prognosis of nonalcoholic steatohepatitis (NASH). We aim to explore novel genes associated with fibrosis progression in NASH.

METHODS

Two human RNA-seq datasets were downloaded from the public database. Weighted gene co-expression network analysis (WGCNA) was used to identify their co-expressed modules and further bioinformatics analysis was performed to identify hub genes within the modules. Finally, based on two single-cell RNA-seq datasets from mice and one microarray dataset from human, we further observed the expression of hub genes in different cell clusters and liver tissues.

RESULTS

7 hub genes (SPP1, PROM1, SOX9, EPCAM, THY1, CD34 and MCAM) associated with fibrosis progression were identified. Single-cell RNA-seq analysis revealed that those hub genes were expressed by different cell clusters such as cholangiocytes, natural killer (NK) cells, and hepatic stellate cells (HSCs). We also found that SPP1 and CD34 serve as markers of different HSCs clusters, which are associated with inflammatory response and fibrogenesis, respectively. Further study suggested that SPP1, SOX9, MCAM and THY1 might be related to NASH-associated hepatocellular carcinoma (HCC). Receiver operating characteristic (ROC) analysis showed that the high expression of these genes could well predict the occurrence of HCC. At the same time, there were significant differences in metabolism-related pathway changes between different HCC subtypes, and SOX9 may be involved in these changes.

CONCLUSIONS

The present study identified novel genes associated with NASH fibrosis and explored their effects on fibrosis from a single-cell perspective that might provide new ideas for the early diagnosis, monitoring, evaluation, and prediction of fibrosis progression in NASH.

Urolithins and intestinal health

There are trillions of microorganisms in the human intestine. They can react to the intestinal microenvironment by metabolizing food or producing small molecular compounds to affect the host's digestive ability and resist the risk of infection and autoimmune diseases. Many studies have revealed that intestinal flora and its metabolites play an important role in human physiology and the development of diseases. Urolithins are kind of intestinal microbiota metabolites of ellagitannins (ETs) and ellagic acid (EA) with potent biological activity in vivo. However, different individuals have different intestinal flora. According to the different metabolites from ETs and EA, it is divided into three metabo-types including UM-A, UM-B and UM-0. This paper reviews the origin of urolithins, the urolithin producing microorganisms and the effects of urolithins on regulating intestinal diseases. This review will provide a theoretical basis for the regulation of urolithins in the homeostasis of intestinal flora and a reference for the scientific utilization of urolithins and foods rich in ETs and EA.

[Development and validation of a prognostic model based on SEER data for patients with esophageal carcinoma after esophagectomy]

OBJECTIVE

To develop a nomogram to predict the long-term survival of patients with esophageal cancer following esophagectomy.

METHODS

We collected the data of 7215 patients with esophageal carcinoma from the Surveillance, Epidemiology, and End Results (SEER) database during the period from 2004 and 2016. Of these patients, 5052 were allocated to the training cohort and the remaining 2163 patients to the internal validation cohort using bootstrap resampling, with another 435 patients treated in the Department of Cardiothoracic Surgery of Jinling Hospital between 2014 and 2016 serving as the external validation cohort.

RESULTS

In the overall cohort, the 1-, 3-, and 5-year cancer-specific mortality rates were 14.6%, 35.7% and 41.6%, respectively. Age (≥80 years vs < 50 years, P < 0.001), gender (male vs female, P < 0.001), tumor site (lower vs middle segment, P=0.013), histology (EAC vs ESCC, P=0.012), tumor grade (poorly vs well differentiated, P < 0.001), TNM stage (Ⅳ vs Ⅰ, P < 0.001), tumor size (> 50 mm vs 0-20 mm, P < 0.001), chemotherapy (yes vs no, P < 0.001), and LNR (> 0.25 vs 0, P < 0.001) were identified as independent risk factors affecting long-term survival of the patients. The nomograms established based on the model for predicting the survival probability of the patients at 1, 3 and 5 years after operation showed a C-index of 0.726 (95% CI: 0.714-0.738) for predicting the overall survival (OS) and of 0.735 (95% CI: 0.727-0.743) for cancer-specific survival (CSS) in the training cohort. In the internal validation cohort, the C-index of the nomograms was 0.752 (95% CI: 0.738-0.76) for OS and 0.804 (95% CI: 0.790-0.817) for CSS, as compared with 0.749 (95% CI: 0.736-0.767) and 0.788 (95%CI: 0.751-0.808), respectively, in the external validation cohort. The nomograms also showed a higher sensitivity than the TNM staging system for predicting long-term prognosis.

CONCLUSION

This prognostic model has a high prediction efficiency and can help to identify the high-risk patients with esophageal carcinoma after surgery and serve as a supplement for the current TNM staging system.

Whole genome and transcriptome analysis enhances precision cancer treatment options

BACKGROUND

Recent advances are enabling delivery of precision genomic medicine to cancer clinics. While the majority of approaches profile panels of selected genes or hotspot regions, comprehensive data provided by whole genome and transcriptome sequencing and analysis (WGTA) presents an opportunity to align a much larger proportion of patients to therapies.

PATIENTS AND METHODS

Samples from 570 patients with advanced or metastatic cancer of diverse types enrolled in the Personalized OncoGenomics (POG) program underwent WGTA. DNA-based data, including mutations, copy number, and mutation signatures, were combined with RNA-based data, including gene expression and fusions, to generate comprehensive WGTA profiles. A multidisciplinary molecular tumour board used WGTA profiles to identify and prioritize clinically actionable alterations and inform therapy. Patient responses to WGTA-informed therapies were collected.

RESULTS

Clinically actionable targets were identified for 83% of patients, 37% of whom received WGTA-informed treatments. RNA expression data were particularly informative, contributing to 67% of WGTA-informed treatments; 25% of treatments were informed by RNA expression alone. Of a total 248 WGTA-informed treatments, 46% resulted in clinical benefit. RNA expression data were comparable to DNA-based mutation and copy number data in aligning to clinically beneficial treatments. Genome signatures also guided therapeutics including platinum, PARP inhibitors, and immunotherapies. Patients accessed WGTA-informed treatments through clinical trials (19%), off-label use (35%), and as standard therapies (46%) including those which would not otherwise have been the next choice of therapy, demonstrating the utility of genomic information to direct use of chemotherapies as well as targeted therapies.

CONCLUSIONS

Integrating RNA expression and genome data illuminated treatment options that resulted in 46% of treated patients experiencing positive clinical benefit, supporting the use of comprehensive WGTA profiling in clinical cancer care.

CLINICAL TRIAL NUMBER

NCT02155621.

[The IL-6/STAT3 signaling pathway mediated by radiotherapy regulates the expression of PD-L1 in esophageal cancer cells]

Objective: To explore the possible mechanism of radiotherapy regulating the expression of PD-L1 in esophageal carcinoma. Methods: Three esophageal cancer cell lines (Eca109, Kyse150, TE1) were irradiated with different doses of X-rays, and 6 Gy+ AG490 group was set. The mRNA expression of PD-L1 was detected by real-time quantitative polymerase chain reaction (RT-qPCR). The protein expressions of PD-L1, STAT3, p-STAT3 were detected by western blotting and the protein level of IL-6 was detected by ELISA. Results: The mRNA expressions of PD-L1 in Eca109, Kyse150 and TE1 were 2.86±0.30, 960.01±21.27 and 106.78±6.67, higher than 1.07±0.15 in normal esophageal cell line HET-1A (P<0.01). The protein expressions of PD-L1 in Eca109, Kyse150 and TE1 were 0.091±0.036, 1.533±0.079 and 0.914±0.035, higher than 0.063±0.01 in normal esophageal cell line HET-1A (P<0.01). After 48 hours of 6 Gy irradiation, the protein expression levels of PD-L1 in Eca109, Kyse150 and TE1 were 0.135±0.007, 1.66±0.06 and 1.32±0.06, higher than 0.09±0.01, 1.21±0.05 and 0.93±0.03 of the 0 Gy group (P<0.01), while the protein expression levels of p-STAT3 in Eca109, Kyse150 and TE1 were 1.44±0.26, 0.75±0.04 and 1.92±0.17, higher than 0.18±0.05, 0.48±0.02 and 0.36±0.06 of the 0 Gy group (P<0.01). IL-6 protein expression increased significantly after different doses of irradiation (P<0.01). After the IL-6/STAT3 signaling pathway was blocked by the specific inhibitor AG490, the expressions of PD-L1 of Eca109, Kyse150 and TE1 in the 6 Gy+ AG490 groups were 0.11±0.03, 1.07±0.08 and 0.96±0.11, without significant differences of 0.09±0.01, 0.96±0.05 and 0.85±0.09 of the 0 Gy group (P>0.05), while the protein expressions of p-STAT3 were 0.76±0.11, 0.59±0.06 and 0.96±0.12, without significant differences of 0.67±0.08, 0.54±0.06 and 0.84±0.11 of the 0 Gy group (P>0.05). Conclusion: Radiotherapy may regulate the expression of PD-L1 in esophageal cancer cells through IL-6 / STAT3 signaling pathway.

Site-specific therapy in cancers of unknown primary site: a systematic review and meta-analysis

Background

Cancer of unknown primary site (CUP) is a term applied to characterize pathologically confirmed metastatic cancer with unknown primary tumor origin. It remains uncertain whether patients with CUP benefit from site-specific therapy guided by molecular profiling.

Patients and methods

A systematic search in PubMed, Web of Science, Embase, Cochrane Library, and ClinicalTrials.gov, and of conference abstracts from January 1976 to January 2021 was performed to identify studies investigating the efficacy of site-specific therapy on patients with CUP. The quality of included studies was evaluated using the Cochrane risk of bias tool and Newcastle–Ottawa scale. Eligible studies were weighted and pooled for meta-analysis. Hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) were assessed to compare the efficacy of site-specific therapy with empiric therapy in patients with CUP. In addition, subgroup analyses were conducted.

Results

Five studies comprising 1114 patients were identified, of which 454 patients received site-specific therapy, and 660 patients received empiric therapy. Our meta-analysis revealed that site-specific therapy was not significantly associated with improved PFS [HR 0.93, 95% confidence interval (CI) 0.74-1.17, P = 0.534] and OS (HR 0.75, 95% CI 0.55-1.03, P = 0.069), compared with empiric therapy. However, during subgroup analysis significantly improved OS was associated with site-specific therapy in the high-accuracy predictive assay subgroup (HR 0.46, 95% CI 0.26-0.81, P = 0.008) compared with the low accuracy predictive assay subgroup (HR 0.93, 95% CI 0.75-1.15, P = 0.509). Furthermore, compared with patients with less responsive tumor types, more survival benefit from site-specific therapy was found in patients with more responsive tumors (HR 0.67, 95% CI 0.46-0.97, P = 0.037).

Conclusions

Our results suggest that site-specific therapy is not significantly associated with improved survival outcomes; however, it might benefit patients with CUP with responsive tumor types.

•

Studies evaluating the role of site-specific therapy guided by molecular profiling in CUP provided contradictory results.

•

Site-specific therapy is not significantly associated with improved survival outcomes in the overall CUP population.

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Molecularly defined site-specific therapy may improve OS only when high-accuracy assays assign CUP to responsive tumor types.