Mechanistic Insights into the N-Hydroxylations Catalyzed by the Binuclear Iron Domain of SznF Enzyme: Key Piece in the Synthesis of Streptozotocin.

SznF, a member of the emerging family of heme-oxygenase-like (HO-like) di-iron oxidases and oxygenases, employs two distinct domains to catalyze the conversion of Nω-methyl-L-arginine (L-NMA) into N-nitroso-containing product, which can subsequently be transformed into streptozotocin. Using unrestricted density functional theory (UDFT) with the hybrid functional B3LYP, we have mechanistically investigated the two sequential hydroxylations of L-NMA catalyzed by SznF's binuclear iron central domain. Mechanism B primarily involves the O-O bond dissociation, forming Fe(IV)=O, induced by the H+/e- introduction to the FeA side of µ-1,2-peroxo-Fe2(III/III), the substrate hydrogen abstraction by Fe(IV)=O, and the hydroxyl rebound to the substrate N radical. The stochastic addition of H+/e- to the FeB side (mechanism C) can transition to mechanism B, thereby preventing enzyme deactivation. Two other competing mechanisms, involving the direct O-O bond dissociation (mechanism A) and the addition of H2O as a co-substrate (mechanism D), have been ruled out.

Efficacy and safety of different PD-1 inhibitors in combination with lenvatinib in the treatment of unresectable primary liver cancer: a multicentre retrospective study.

Immune checkpoint inhibitors (ICIs) are safe and efficacious treatments for advanced primary liver cancer (PLC). The efficacy of different ICIs in the treatment of liver cancer remains unclear. The purpose of this study was to explore whether there is a difference in the efficacy and safety of various programmed cell death protein 1 (PD-1) inhibitors in combination with lenvatinib in the treatment of unresectable PLC. Patients with PLC treated with lenvatinib in combination with PD-1 inhibitors (camrelizumab, tislelizumab, sintilimab, or pembrolizumab) between January 2018 and December 2021 were retrospectively enrolled. Tumor response, adverse events, and grades were evaluated. Kaplan-Meier analysis and log-rank test were used to compare the overall survival and progression-free survival of patients treated with different PD-1 inhibitors. Cox regression analysis was used for univariate and multivariate analyses to identify clinical variables related to treatment efficacy. This study included a total of 176 patients who received a combination of lenvatinib and PD-1 inhibitors. Of these, 103 patients received camrelizumab, 44 received tislelizumab, 20 received sintilimab, and 9 received pembrolizumab. There was no significant difference in the pairwise comparison of camrelizumab, tislelizumab, sintilimab, and pembrolizumab using Kaplan-Meier survival analysis. Adverse events occurred in 40 (22.7%) patients (grade ≥ 3, 2.3%). The incidence of grade 3 adverse events among the four PD-1 inhibitor groups was below 5%. Camrelizumab, tislelizumab, sintilimab, and pembrolizumab are viable options for patients with unresectable PLC. These PD-1 inhibitors in combination with lenvatinib showed good safety profiles. The results guide selecting treatment for patients with unresectable PLC.

Predictive Value of the Hepatic Immune Predictive Index for Patients with Primary Liver Cancer Treated with Immune Checkpoint Inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have improved survival outcomes and resulted in long-term responses in primary liver cancer in some patients. Nevertheless, not all patients with PLC could benefit from immunotherapy. Therefore, it is necessary to identify patients suitable for such therapy. METHODS: 215 patients with primary liver cancer with immunotherapy from Nanfang Hospital were screened between August 2018 and October 2020 as a training set and our validation set included 71 patients of hepatocellular carcinoma from Jiangxi Cancer Hospital from May 2019 to July 2021. The primary endpoint was the disease control rate (DCR), and the secondary endpoints were overall survival (OS) and progression-free survival. RESULTS: In the training set, neutrophil-lymphocyte ratio (NLR) ≥3 and alpha-fetoprotein (AFP) level ≥20 ng/mL were independently associated with non-DCR in the training set after adjusting for distant metastasis at baseline and targeted therapy combination. Furthermore, a hepatic immune predictive index (HIPI) based on NLR and AFP level was developed and patients with poor HIPI associated with worse clinical outcomes. In validation set, high HIPI was associated with poor OS. CONCLUSION: HIPI, based on NLR and AFP level, is an effective indicator in ICI-treated patients with primary liver cancer. Our findings may help guide the selection and on-treatment strategies for immunotherapies for primary liver cancer patients.

Use of computed tomography-derived body composition to determine the prognosis of patients with primary liver cancer treated with immune checkpoint inhibitors: a retrospective cohort study.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have been used to successfully treat primary liver cancer (PLC); however, identifying modifiable patient factors associated with therapeutic benefits is challenging. Obesity is known to be associated with increased survival after ICI treatment; however, the relationship between body composition (muscle, fat) and outcomes is unclear. This study aimed to evaluate the association between sarcopenia and CT-derived fat content and the prognosis of ICIs for the treatment of PLC. METHODS: In this retrospective cohort study of 172 patients with PLC, we measured the skeletal muscle index (SMI), skeletal muscle density, visceral adipose tissue index, subcutaneous adipose tissue index, total adipose tissue index (TATI), and visceral-to-subcutaneous adipose tissue area ratio using CT. In addition, we analyzed the impact of body composition on the prognosis of the patients. Multivariate Cox regression analysis was used to screen for influencing factors. RESULTS: Among the seven body composition components, low SMI (sarcopenia) and low TATI were significantly associated with poor clinical outcomes. Multivariate analysis revealed that sarcopenia (hazard ratio [HR], 5.39; 95% confidence interval [CI], 1.74-16.74; p = 0.004) was a significant predictor of overall survival (OS). Kaplan-Meier curves showed that sarcopenia and TATI were significant predictors of OS. Body mass index was not associated with survival outcomes. CONCLUSIONS: Sarcopenia and fat tissue content appear to be independently associated with reduced survival rates in patients with PLC treated with ICIs.

Mechanism for the Halogenation and Azidation of Lysine Catalyzed by Non-heme Iron BesD Enzyme.

Selective halogenation is important in synthetic chemistry. BesD, a new member of the non-heme Fe(II)/α-ketoglutarate (αKG)-dependent halogenase family, can activate the sp3 C-H bond and halogenate lysine, in particular without a carrier protein. Using the density functional calculations, a chlorination mechanism in BesD has been proposed, mainly including the formation of Cl-Fe(IV)=O through the αKG decarboxylation, the isomerization of Cl-Fe(IV)=O, the substrate hydrogen abstraction by Fe(IV)=O, and the rebound of chloro to the substrate carbon radical. The hydrogen abstraction is rate-limiting. The isomerization of Cl-Fe(IV)=O is essential for the hydrogen abstraction and the chiral selectivity. The BesD-catalyzed bromination and azidation of lysine adopt the same mechanism as the chlorination. The hardly-changed overall barriers indicate that the introduced ligands (X) do not affect the reaction rate significantly, implying that the X-introduced reactions catalyzed by BesD may be extended to other X anions.

Splenomegaly in predicting the survival of patients with advanced primary liver cancer treated with immune checkpoint inhibitors.

BACKGROUND & AIMS: Immune checkpoint inhibitors (ICIs) play an increasingly important role in the treatment of primary liver cancer (PLC). Some patients with PLC experience symptoms of splenomegaly. Splenomegaly may affect the efficacy of ICIs due to an imbalance of the immune microenvironment. Currently, there is a lack of evidence on the relationship between splenomegaly and prognosis in patients with PLC treated with ICIs. This study analyzed the relationship between splenomegaly and prognosis in patients with PLC treated with ICIs. METHODS: In this retrospective cohort study of 161 patients with PLC treated with ICIs, splenomegaly was diagnosed using computed tomography or magnetic resonance imaging and the impact of splenomegaly on patient survival was analyzed. RESULTS: Through univariate and multivariate Cox regression analyses, we determined that splenomegaly was associated with shortened overall survival (p = 0.002) and progression-free survival (p = 0.013) in patients with PLC treated with ICIs. Kaplan-Meier analysis further validated our results. The overall survival and progression-free survival of patients with splenomegaly were significantly shorter than those of patients without splenomegaly (p < 0.01 and p = 0.02, respectively). CONCLUSIONS: We concluded that splenomegaly was a predictor of prognosis in patients with PLC treated with ICIs. This is the first study to report this important finding.

Breakfast consumption frequency is associated with dyslipidemia: a retrospective cohort study of a working population.

BACKGROUND: Dyslipidemia is a significant contributor to cardiovascular and cerebrovascular diseases. Research on the relationship between breakfast consumption frequency and dyslipidemia in the working population is lacking. Therefore, we aimed to investigate this relationship based on a retrospective cohort study of a large working population in China. METHODS: This retrospective cohort study used data from the physical examinations and questionnaire survey of working participants at Nanfang Hospital from January 20, 2015 to October 16, 2020. Univariate and multivariate analyses were conducted to explore the relationship between breakfast consumption frequency and dyslipidemia in this working population (n = 7644). RESULTS: The prevalence of dyslipidemia among the participants was 26.4%. The univariate logistic regression test showed that the breakfast consumption frequency was inversely correlated with dyslipidemia. After adjusting for multiple factors, such as sex, age, body mass index, hypertension, hyperuricaemia, diabetes, smoking status, alcohol consumption, education level, marital status, long-term exposure to kitchen oil fumes, attending business dinners, and sleep time, it was found that breakfast consumption remained inversely associated with dyslipidaemia. The odds ratio for daily breakfast consumption was 0.466 (95% confidence interval 0.283-0.770, P = 0.003). After adjusting for confounding factors, we found that the higher the frequency of breakfast consumption, the lower the odds ratios for hypertriglyceridaemia. CONCLUSIONS: This study demonstrated that breakfast consumption frequency was inversely correlated with dyslipidemia. The higher the frequency of breakfast, the lower the risk of hypertriglyceridaemia. This study provides a basis on which dietary suggestions for the working population and lifestyle guidance for patients with a clinical need to prevent dyslipidemia can be made.

Identification of Potential Core Genes Between Primary and Metastatic Malignant Melanoma and Analysis of Their Immune Correlation.

PURPOSE: To identify the potential differential genes between primary and metastatic melanoma, screen out immune-related genes in core genes and analyze their immune correlation, thus searching for the early diagnostic biomarkers of cutaneous malignant melanoma (CMM) and the targets of curbing metastasis. MATERIALS AND METHODS: We analyzed two microarray datasets (GSE8401 and GSE46517) derived from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between primary and metastatic melanoma were screened out using the GEO2R tool. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to identify the functions and pathways of DEGs. We analyzed protein-protein interaction of these DEGs based on the Search Tool for the Retrieval of Interacting Genes database and showed by Cytoscape software. In addition, the online Gene Expression Profiling Interactive Analysis tool (GEPIA) was used to analyze the prognostic value of hub genes expressed in metastatic melanoma patients. Immune-related genes in hub genes were screened and further analyzed. RESULTS: A total of 178 upregulated DEGs and 4 downregulated DEGs were identified. 23 terms and 4 pathways were confirmed related to metastatic melanoma. Ten hub genes with a high degree of connectivity were found. Overexpression of three hub genes (DSG1, FLG, PKP1) (P<0.01) was associated with metastasis and poor prognosis of CMM. Among them, the patients with overexpression of PKP1 suffered shorter survival. In addition, 2 immune-related genes (EGFR and CDH1) in hub genes were screened out and both of them were related to anti-tumor immunity, although their expression level did not affect the overall survival of CMM patients significantly. CONCLUSION: Our study suggests that DSG1, FLG and PKP1 were overexpressed in metastatic melanoma compared with primary melanoma, and overexpression of these three genes was an unfavorable prognostic factor ifor CMM patients, which may indicate that they are associated with promoting metastasis of malignant melanoma. EGFR and CDH1 play a crucial role in anti-tumor immunity for CMM. Further research is needed to explore the value of these genes in the inhibition of metastasis and treatment of CMM.

Lung metastasis and lymph node metastasis are risk factors for hyperprogressive disease in primary liver cancer patients treated with immune checkpoint inhibitors.

BACKGROUND: At present, some cancer patients experience hyperprogressive disease (HPD) after receiving immunotherapy. This study used the Response Evaluation Criteria in Solid Tumors 1.1 to evaluate the incidence of HPD in patients receiving immune checkpoint inhibitors (ICIs) for treating primary liver cancer (PLC) and to explore the risk factors for HPD. METHODS: This retrospective, single-center study included patients with PLC who were treated with ICIs. The RECIST 1.1 was used to determine patients with HPD. Univariate and multivariate regression analyses were performed to explore the risk factors for HPD, and clinical variables with prognostic significance for HPD were included to establish a risk model. RESULTS: Among 129 patients with PLC treated with ICIs, HPD occurred in 13 patients (10.1%). In the multivariate regression analysis, lymph node metastasis and lung metastasis were risk factors for HPD. The area under the curve of the risk model, established by including lymph node metastasis, lung metastasis, neutrophil-lymphocyte ratio, albumin, and performance status, was 0.801 (P<0.001). The progression-free survival of HPD patients was significantly worse than that of non-HPD patients (P<0.001). CONCLUSIONS: In this study, 10.1% of patients with PLC had HPD. Compared with the non-HPD patients, lung metastasis and lymph node metastasis were independent risk factors of HPD.