Chuangxinmycin (CM) from Actinoplanes tsinanensis was an antibiotic discovered by Chinese scientists about 40 years ago. It contains a new heterocyclic system of indole fused with dihydrothiopyran, whose biosynthetic mechanism remains unclear. CM is used as an oral medicine in the treatment of bacterial infections in China. The simple structure makes CM as an attractive candidate of structure modification for improvement of antibacterial activity. Recently, we analyzed the secondary metabolites of Actinoplanes tsinanensis CPCC 200056, a CM producing strain, as a natural CM analogue. We discovered the first natural CM analogue 3-demethylchuangxinmycin (DCM) as a new natural product. Compared to CM, DCM exhibited a much weaker activity in the inhibition of the bacterial strains tested. The finding provides valuable information for the structure-activity relationship in the biosynthesis of CM.

Objective:To explore the efficacy and safety of tislelizumab combined with zanubrutinib in the treatment of refractory diffuse large B-cell lymphoma (DLBCL).Methods:A prospective observational study was conducted. A total of 10 patients with refractory DLBCL admitted to Beijing Chaoyang District Third Ring Cancer Hospital, a specialist medical consortium of Cancer Hospital Chinese Academy of Medical Sciences from November 2020 to February 2023 were prospectively collected. All the 10 refractory DLBCL patients at least received first-line systemic therapy containing rituximab; and they were given tislelizumab 200 mg, intravenous infusion, on day 1 and zanubrutinib 160 mg, orally, twice a day, day 1-day 21, with 21 days as 1 cycle; 6 patients received second-line therapy and 4 patients received ≥ third-line therapy. Subsequent regimens were added with rituximab (375 mg/m 2, intravenous infusion on day 1). The primary endpoint will be reached 12 months after enrollment if there was no disease progression or other events that were scheduled to withdraw from the study. The therapeutic efficacy was summarized at the end of the follow-up in March 2023. Kaplan-Meier method was used to make survival analysis and the adverse reactions were summed up. Results:There were 6 males and 4 females, all at stage Ⅲ-Ⅳ; and age [ M ( Q1, Q3)] was 55 years (50 years, 69 years). All 10 patients completed 90 cycles of treatment with tislelizumab and zanubrutinib, with the cycle number of 8 cycles (2 cycles, 24 cycles). The follow-up time was 19 months (11 months, 28 months); 4 cases achieved complete remission, 3 cases achieved partial remission and 1 case had the stable disease. The progression-free survival was 8.5 months (1.3 months, 27.0 months); the median remission duration time and median overall survival time were not reached. Treatment-related adverse reactions included 2 cases of neutropenia, 1 case of anemia, and 1 case of elevated alanine aminotransferase and aspartate aminotransferase, all of which were grade 1-2. Conclusions:Tislelizumab combined with zanubrutinib has good clinical efficacy and safety in the treatment of refractory DLBCL.

Objective: To investigate the expression of 11β-hydroxysteroid dehydrogenase (11β-HSD) in polyps of patients with chronic rhinosinusitis with nasal polyps (CRSwNP) and its correlation with glucocorticoid sensitivity. Methods: The prospective study method was applied. Forty-three adult CRSwNP patients from Otorhinolaryngology Hospital, First Affiliated Hospital of Sun Yat-sen University between April 2016 and June 2017 were enrolled in this study. There were 19 males and 24 females with the age of (37.44±7.42) years old. The endoscopic scores by nasal Polyps Grading System before and after one-week prednisone treatment (0.5 mg/(kg·d)) were evaluated. The response of glucocorticoid by the total endoscopic scores was estimated. According to the patient′s reduced nasal polyp endoscopic score, patients were devided into nasal polyps insensitive to glucocorticoids treatment group (insensitive group) and nasal polyp sensitive to glucocorticoids treatment group (sensitive group). The expression of 11β-HSD1, 11β-HSD2 in nasal polyps were measured by Real-time PCR (RT-PCR), Western Blot and immunohistochemisty. According to the clinical data, the Logistic regression models and receiver operation characteristics (ROC) curves were used to explore the predictor for glucocorticoid response in CRSwNP. Results: The expression of 11β-HSD1 and 11β-HSD1/11β-HSD2 was higher in sensitive group than that of insensitive group, while the expression of 11β-HSD2 was lower (rank average was 26.08 vs 16.33, 27.24 vs 14.72, 18.66 vs 26.64, Z value was -2.511, 0.323, -2.059, respectively, all P<0.05). The endoscopic scores in CRSwNP group declined whereas the expression of 11β-HSD1/11β-HSD2 increased (r=0.528, P=0.001), while the cutoff value of the ratio of 11β-HSD1/11β-HSD2 was 2.290 (sensitivity was 79.17%, specificity was 88.89%). Conclusions There is a positive correlation between the response of glucocorticoid and the ratio of 11β-HSD1/11β-HSD2, which could be used as a marker in predicting the level of tissue response to glucocorticoid therapy in CRSwNP.

Chuangxinmycin is an antibiotic isolated from CPCC 200056 in the 1970s with a novel indole-dihydrothiopyran heterocyclic skeleton. Chuangxinmycin showed antibacterial activity and efficacy in mouse infection models as well as preliminary clinical trials. But the biosynthetic pathway of chuangxinmycin has been obscure since its discovery. Herein, we report the identification of a stretch of DNA from the genome of CPCC 200056 that encodes genes for biosynthesis of chuangxinmycin by bioinformatics analysis. The designated cluster was then confirmed to be responsible for chuangxinmycin biosynthesis by direct cloning and heterologous expressing in M1146. The cytochrome P450 CxnD was verified to be involved in the dihydrothiopyran ring closure reaction by the identification of seco-chuangxinmycin in M1146 harboring the gene cluster with an inactivated . Based on these results, a plausible biosynthetic pathway for chuangxinmycin biosynthesis was proposed, by hijacking the primary sulfur transfer system for sulfur incorporation. The identification of the biosynthetic gene cluster of chuangxinmycin paves the way for elucidating the detail biochemical machinery for chuangxinmycin biosynthesis, and provides the basis for the generation of novel chuangxinmycin derivatives by means of combinatorial biosynthesis and synthetic biology.