Computational design of an imine reductase: mechanism-guided stereoselectivity reversion and interface stabilization.

Imine reductases (IREDs) are important biocatalysts in the asymmetric synthesis of chiral amines. However, a detailed understanding of the stereocontrol mechanism of IRED remains incomplete, making the design of IRED for producing the desired amine enantiomers challenging. In this study, we investigated the stereoselective catalytic mechanism and designed an (R)-stereoselective IRED from Paenibacillus mucilaginosus (PmIR) using pharmaceutically relevant 2-aryl-substituted pyrrolines as substrates. A putative mechanism for controlling stereoselectivity was proposed based on the crucial role of electrostatic interactions in controlling iminium cation orientation and employed to achieve complete inversion of stereoselectivity in PmIR using computational design. The variant PmIR-Re (Q138M/P140M/Y187E/Q190A/D250M/R251N) exhibited opposite (S)-stereoselectivity, with >96% enantiomeric excess (ee) towards tested 2-aryl-substituted pyrrolines. Computational tools were employed to identify stabilizing mutations at the interface between the two subunits. The variant PmIR-6P (P140A/Q190S/R251N/Q217E/A257R/T277M) showed a nearly 5-fold increase in activity and a 12 °C increase in melting temperature. The PmIR-6P successfully produced (R)-2-(2,5-difluorophenyl)-pyrrolidine, a key chiral pharmaceutical intermediate, at a concentration of 400 mM with an ee exceeding 99%. This study provides insight into the stereocontrol elements of IREDs and demonstrates the potential of computational design for tailored stereoselectivity and thermal stability.

Drug-eluting beads versus conventional transarterial chemoembolization for the treatment of unresectable hepatocellular carcinoma: A meta-analysis.

BACKGROUND: Transarterial chemoembolization (TACE) consists of conventional TACE (cTACE) and drug-eluting beads TACE (DEB-TACE). The benefits of the 2 treatments remain controversial. We conduct this meta-analysis to assess the efficacy and safety of the 2 methods for the patients with unresectable hepatocellular carcinoma. METHODS: In order to get a sound conclusion, we did thorough search all relevant studies with clear and stringent keyword criteria on the main databases. Objective tumor response rate, overall survival (OS) rate and adverse events were calculated and analyzed by RevMan 5.3 software. The random-effects or fixed-effects model was applied to pool the estimates according to Cochran Q test and I2 statistics. RESULTS: Twenty-four studies involving 2987 patients were eligible. DEB-TACE significantly improved objective tumor response rate (OR) (risk ratio [RR] = 1.27, 95% confidence interval [CI] [1.08, 1.48]; P = .003). While as for 1-year, 2-year, 3-year, 5-year OS rates, there were no evidences to indicate that DEB-TACE was significantly better than cTACE (RR = 1.05, 95% CI [0.99, 1.11]; P = .08), (RR = 1.02, 95% CI [0.93, 1.11]; P = .68), (RR = 0.92, 95% CI [0.77, 1.10]; P = .37), (RR = 0.92, 95% CI [0.47, 1.80]; P = .81), respectively. Adverse events rate (AE) was also similar in both groups (RR = 1.11, 95% CI [0.99,1.26]; P = .08). CONCLUSION: This meta-analysis demonstrates that DEB-TACE is not superior than cTACE regarding to OS and AE. However, DEB-TACE still be considered to provide a better objective tumor response rate for patients with unresectable hepatocellular carcinoma.

Anisotropic Microspheres-Cryogel Composites Loaded with Magnesium l-Threonate Promote Osteogenesis, Angiogenesis, and Neurogenesis for Repairing Bone Defects.

To achieve osteogenesis, angiogenesis, and neurogenesis for repairing bone defects, we constructed an anisotropic microspheres-cryogel composite loaded with magnesium l-threonate (MgT). These composites were prepared by the photo-click reaction of norbornene-modified gelatin (GB) in the presence of MgT-loaded microspheres through the bidirectional freezing method. The composites possessed an anisotropic macroporous (around 100 µm) structure and sustained release of bioactive Mg2+, which facilitate vascular ingrowth. These composites could significantly promote osteogenic differentiation of bone marrow mesenchymal stem cells, tubular formation of human umbilical vein vessel endothelial cells, and neuronal differentiation in vitro. Additionally, these composites significantly promoted early vascularization and neurogenesis as well as bone regeneration in the rat femoral condyle defects. In conclusion, owing to the anisotropic macroporous microstructure and bioactive MgT, these composites could simultaneously promote bone, blood vessel, and nerve regeneration, showing great potential for bone tissue engineering.

Microwave-assisted decarboxylative reactions: advanced strategies for sustainable organic synthesis.

The decarboxylation or decarboxylative coupling reactions of carboxylic acids and their derivatives are some of the most powerful tools for the construction of platform molecules and valuable chemicals in organic synthetic chemistry. Additionally, microwave-assisted technology, which is strongly endorsed by industry in addition to academia, has been recognized as an alternative synthetic chemist's toolbox. Many decarboxylative reactions using microwave-assisted technology have been developed as an advanced strategy for sustainable organic synthesis for decades. This review highlights the recent developments in microwave-assisted decarboxylative reactions, including transition-metal-catalyzed and metal-free approaches.

[Effect of electroacupuncture on gastrointestinal function of patients after laparoscopic cholecystectomy under general anesthesia].

OBJECTIVE: To observe the effects of electroacupuncture at bilateral Zusanli(ST36), Shangjuxu(ST37), and Sanyinjiao (SP6) acupoints on gastrointestinal function after laparoscopic cholecystectomy under general anesthesia. METHODS: A total of 150 patients(American Society of Anesthesiologists［ASA］ grades Ⅰ and Ⅱ) undergoing laparoscopic cholecystectomy in the Department of Hepatobiliary Surgery of the First Affiliated Hospital of Guangzhou University of Chinese Medicine were randomly assigned into three groups: electroacupuncture group (n=50), simple acupuncture group (n=50), and control group (n=50). Patients in the control group received routine treatment；on the basis of routine treatment, patients in the simple acupuncture group were acupunctured at bilateral ST36, ST37 and SP36；patients in the electroacupuncture group were treated with electroacupuncture at bilateral ST36, ST37 and SP36（50 Hz，5 mA）. In both simple acupuncture group and electroacupuncture group, the corresponding treatments were conducted 1 h after surgery, Patients as well as in the morning (8:00-10:00) and afternoon (14:00-16:00) on the first day after surgery, 30 min each time. The time of bowel sound recovery, the time to the first postope-rative exhaust and defecation, the time of postoperative fluid diet recovery, abdominal pain score, and gastrointestinal reaction score were recorded and analyzed. RESULTS: Compared with the control group, the electroacupuncture group and the simple acupuncture group showed shortened time of bowel sound recovery, shortened time to the first postoperative exhaust and defecation, and shortened time of postoperative liquid diet recovery (P<0.01), as well as decreased postoperative abdominal pain score and gastrointestinal reaction score (P<0.01). Furthermore, the time of bowel sound recovery, the time to the first postoperative exhaust and defecation, and the time of postoperative liquid diet recovery were shortened in the electroacupuncture group compared with those in the simple acupuncture group (P<0.01). The total effective rate of electroacupuncture group was 94.0% (47/50), the total effective rate of simple acupuncture group was 88.0% (44/50), significantly higher than 78.0% (39/50) in the control group (P<0.05). CONCLUSION: Both electroacupuncture and simple acupuncture can promote the recovery of gastrointestinal function in patients after laparoscopic cholecystectomy under general anesthesia, and electroacupuncture is superior to simple acupuncture,but they have no significant difference in alleviating postoperative abdominal pain and gastrointestinal reactions.

Long noncoding RNA matrilineal expression gene 3 inhibits hepatocellular carcinoma progression by targeting microRNA-5195-3p and regulating the expression of forkhead box O1.

We investigated the effect of the long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) on hepatocellular carcinoma (HCC) tumorigenesis and progression by targeting miR-5195-3p and transcription factor forkhead box O1 (FOXO1) to identify a novel target for HCC treatment. HCC clinical samples were collected, and cell counting kit-8 (CCK-8), and transwell migration and invasion assays were performed. Furthermore, interaction was detected via double luciferase reporter and RNA pull-down assays. MEG3, miR-5195-3p, and FOXO1 expression was determined by quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting. Xenograft tumor models were established to investigate the effect of MEG3 in vivo. Compared with normal tissues, MEG3 expression was significantly downregulated in HCC tissues. MEG3 overexpression inhibited the viability and migration of HCC cells. Double luciferase reporter and RNA pull-down assays confirmed the binding between MEG3 and miR-5195-3p as well as between miR-5195-3p and FOXO1. RT-qPCR and Western blotting results showed that MEG3 inhibited the expression of miR-5195-3p and promoted that of FOXO1. Additionally, MEG3 overexpression inhibited HCC tumorigenesis and progression in xenograft tumor models while depletion of MEG3 exerted the opposite way. Therefore, the lncRNA MEG3 inhibits HCC tumorigenesis and progression through the miR-5195-3p/FOXO1 signaling axis.

Chemodivergent Synthesis of Oxazolidin-2-ones via Cu-Catalyzed Carboxyl Transfer Annulation of Propiolic Acids with Amines.

Carboxylic acids are widely found in natural products and bioactive molecules and have served as raw material compounds in industry. We now report the first example of copper(I)-catalyzed carboxyl transfer annulation of propiolic acids with amines, thereby chemodivergently constructing the oxazolidine-2-ones. In this reaction, two kinds of key propargyamine intermediates were formed through sequential CuI/NBS-catalyzed oxidative deamination/decarboxylative alkynylation or CuI-catalyzed decarboxylative hydroamination/alkynylation. The advantages of this decarboxylative coupling/carboxylative cyclization are showcased in the atom economy, chemical specificity, and functional group tolerance.

Postoperative liver metastasis of primary inflammatory pseudotumorous follicular dendritic cell sarcoma of the spleen: a case report.

Follicular dendritic cell sarcoma (FDCS) is a rare and low incidence tumor. So far, there is no standard treatment for the disease. Surgery is the main treatment for FDCS. Here, we report the case of a 51-year-old woman who was admitted with the chief complaint of "spleen-occupying lesion detected via physical examination more than 1 month ago". Spiral plain scan and enhanced computed tomography (CT) of the upper abdomen showed a vascular-derived tumor, with a high possibility of hemangioma or hemangiolymphangioma. Later, on 25 December 2019, the patient underwent laparoscopic splenectomy, and the pathological diagnosis of primary splenic FDCS was made. The patient did not receive adjuvant chemotherapy or radiotherapy. At a regular follow-up inspection 11 months later, on 18 December 2020, an abdominal scan + enhanced CT revealed multiple new abnormal intrahepatic nodules, which combined with her history, indicated the possibility of metastases. Subsequently, she was readmitted to hospital and surgical treatment was decided upon after multi-disciplinary consultation and discussion. Laparoscopic S1/S3/S4/S5 hepatectomy plus cholecystectomy was performed on 31 December 2020. The postoperative pathology findings revealed (liver tumor, S3, S4, S5) metastatic inflammatory pseudotumor follicular dendritic sarcoma, tumor diameter 0.6-1.2 cm. Due to the lack of clinical reports on postoperative organ metastasis of this disease, less experience, and controversy in drug selection of radiotherapy and chemotherapy, the patient refused to receive radiotherapy and chemotherapy. She now undertakes regular outpatient reexamination, and has been followed-up until now, during which time she has not progressed, and the efficacy is considered satisfactory.

Efficient synthesis of bepotastine and cloperastine intermediates using engineered alcohol dehydrogenase with a hydrophobic pocket.

(S)-4-Chlorophenylpyridylmethanol and (R)-4-chlorobenzhydrol are key pharmaceutical intermediates for the synthesis of bepotastine and cloperastine, respectively. However, the biocatalytic approach to prepare these bulky diaryl ketones remains challenging because of the low activity of naturally occurring alcohol dehydrogenases (ADH). In the present study, ADH seq5, which has an adequate binding pocket volume and accepts bulky diaryl ketones, was further engineered with a binding pocket of increased hydrophobicity. Based on molecular simulation and binding free energy analyses, a small mutation library was constructed, and mutant seq5-D150I with a threefold increase in kcat and a low Km was obtained successfully. The comparison of kinetic parameters, binding free energy, docking conformation, and critical catalytic distances calculated by molecular dynamic simulations revealed the source of increased activity. To develop a practical approach with seq5-D150I, reaction conditions including pH, temperature, buffer, and metal ions were optimised and applied to synthesise (S)-4-chlorophenylpyridylmethanol and (R)-4-chlorobenzhydrol with high enantiomeric excess. The space-time yields for (S)-4-chlorophenylpyridylmethanol and (R)-4-chlorobenzhydrol increased dramatically to as high as 263.4 g∙L-1 day-1 and 150 g∙L-1 day-1, respectively, which, to our knowledge, is the highest reported yield to date. These results show that the biocatalytic approach with seq5-D150I may be practical for future industrial applications.Key points An alcohol dehydrogenase was engineered based on binding free energy analysis. The mutant seq5-D150I obtained a threefold increase in kcat and a low Km. Two important pharmaceutical intermediates were obtained with high space-time yield.

m6A-Induced LncRNA MEG3 Suppresses the Proliferation, Migration and Invasion of Hepatocellular Carcinoma Cell Through miR-544b/BTG2 Signaling.

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Long non-coding RNA plays an important role in the development of HCC. This study analyzed the impact of MEG3 on malignant behavior of HCC and explored its possible molecular mechanism. METHODS: Expression of MEG3 in HCC tissues and cell lines was measured by qRT-PCR. Transfection efficiency of MEG3 was verified by qRT-PCR. Cell proliferation, transwell migration, invasion and cell cloning assays were used to detect the effect of MEG3 on the proliferation, migration and invasion ability of HCC cells. The bioinformatics analysis was applied to predict the binding between miR-544b and MEG3 as well as BTG2. Luciferase reporter assay was performed to verify their interaction. Finally, the m6A modification of MEG3 by METTL3 was identified through RIP experiments. RESULTS: MEG3 was lowly expressed in HCC tissues and cells. Overexpression of MEG3 inhibits the proliferation, migration and invasion of HCC cells. MiR-544b can be sponged by MEG3, and overexpression of miR-544b reverses the anti-cancer effect of MEG3. We further confirmed that BTG2 gene is the target gene of miR-544b. Epigenetic studies have shown that METTL3-mediated N6-methyladenosine modification led to MEG3 downregulation. CONCLUSION: In HCC, MEG3 and BTG2 are lowly expressed while miR-544b is highly expressed. MEG3 regulates the expression of BTG2 through miR-544b, thus affecting the malignant behavior of HCC. METTL3 regulates the m6A modification of MEG3 and its expression. This study clarified the role of MEG3/miR-544b/BTG2 axis in HCC and also provided new targets for HCC research.

Erratum: microRNAs carried by exosomes promote epithelial-mesenchymal transition and metastasis of liver cancer cells.

[This corrects the article on p. 6811 in vol. 12, PMID: 33194074.].

microRNAs carried by exosomes promote epithelial-mesenchymal transition and metastasis of liver cancer cells.

In this study, transforming growth factor-ß1 treatment effectively induced epithelial-mesenchymal transition (EMT) of SMMC-7721 cells, and the expression and function of microRNAs (miRNAs) were determined to understand the processes involved in liver cancer metastasis. Nanoparticle tracking analysis and western blotting were performed to identify exosomes. Transwell and MTS assays were used to assess cell migration and proliferation, respectively. Immunofluorescence microscopy was used to identify the metastasis of exosomes in cells. High-throughput sequencing was used to identify mRNAs and miRNAs in cells and exosomes, respectively. The identified differentially expressed miRNAs (DEmis) were further confirmed using quantitative real-time polymerase chain reaction. An miRNA-target mRNA interaction network was constructed using Cytoscape_V2_8_3. SPSS version 16.0 software with one-way analysis of variance was used for statistical analysis. P < 0.05 was considered statistically significant. The overall size of exosomes in EMT SMMC-7721 cells was smaller than that in normal SMMC-7721 cells. Exosomes of EMT SMMC-7721 cells could promote cell migration and invasion in several cell lines. We identified differentially expressed mRNAs (DEms) and DEmis. Among them, a total of 60 and 78 DEms were upregulated and downregulated, respectively, in EMT SMMC-7721 cells compared with those in SMMC-7721 cells. A total of 709 and 123 DEmis were upregulated and downregulated, respectively, in exosomes in EMT SMMC-7721 cells compared with those in SMMC-7721 cells. hsa-miR-24-3p and hsa-miR-21-5p were further selected for knockdown experiments. Exosomes in cells with hsa-miR-24-3p knockdown could effectively inhibit EMT. hsa-miR-24-3p may be one of the most important molecular markers for EMT in liver cancer, which provides novel clues for the mechanisms involved in liver cancer metastasis.

Laparoscopic versus open major liver resection for hepatocellular carcinoma: systematic review and meta-analysis of comparative cohort studies.

BACKGROUND: The application of laparoscopic liver resection (LLR) has expanded rapidly in recent decades. Although multiple authors have reported LLR shows improved safety and efficacy in treating hepatocellular carcinoma (HCC) compared with open liver resection (OLR), laparoscopic (LMLR) and open (OMLR) major liver resections for HCC treatment remain inadequately evaluated. This work aimed to test the hypothesis that LMLR is safer and more effective than OMLR for HCC. METHODS: Comparative cohort and registry studies on LMLR and OMLR, searched in PubMed, the Science Citation Index, EMBASE, and the Cochrane Library, and published before March 31, 2018, were collected systematically and meta-analyzed. Fixed- and random-effects models were employed for generating pooled estimates. Heterogeneity was assessed by the Q-statistic. RESULTS: Nine studies (1173 patients) were included. Although the pooled data showed operation time was markedly increased for LMLR in comparison with OMLR (weighted mean difference [WMD] 74.1, 95% CI 35.1 to 113.1, P = 0.0002), blood loss was reduced (WMD = - 107.4, 95% CI - 179.0 to - 35.7, P = 0.003), postoperative morbidity was lower (odds ratio [OR] 0.47, 95% CI 0.35 to 0.63, P <  0.0001), and hospital stay was shorter (WMD = - 3.27, 95% CI - 4.72 to - 1.81, P <  0.0001) in the LMLR group. Although 1-year disease-free survival (DFS) was increased in patients administered LMLR (OR = 1.55, 95% CI 1.04 to 2.31, P = 0.03), other 1-, 3-, and 5-year survival outcomes (overall survival [OS] and/or DFS) were comparable in both groups. CONCLUSIONS: Compared with OMLR, LMLR has short-term clinical advantages, including reduced blood loss, lower postsurgical morbidity, and shorter hospital stay in HCC, despite its longer operative time. Long-term oncological outcomes were comparable in both groups.

Novel designed azo substituted semi-cyanine fluorescent probe for cytochrome P450 reductase detection and hypoxia imaging in cancer cells.

A hypoxia activated fluorescent probe AZO-Cy which contains an azo group conjugated to the electron withdrawing part of the fluorescent dye was synthesized. In the presence of NADH, AZO-Cy displayed high selectivity and sensitivity to cytochrome P450 reductase (CPR) under low p O2 . The probe showed high anti-interference capability in the presence of other biothiols and ions. In A549 cell imaging, the fluorescence intensity is increased about 11-fold under hypoxia compared to normoxia conditions. Further inhibitor experiments showed that CPR is not the only reductase that can take part in the process of azo bond reduction. The probe AZO-Cy displayed high oxygen sensitivity in the identified different hypoxic status of tumor cells which provides huge potential application toward in vivo hypoxia detection.

Comparison of hepatic resection and transarterial chemoembolization for UICC stage T3 hepatocellular carcinoma: a propensity score matching study.

BACKGROUND: The optimal therapeutic strategy in UICC stage T3 hepatocellular carcinoma (HCC) patients that maximizes both safety and long-term outcome has not yet been determined. Our aim was to compare clinical outcomes following hepatic resection (HR) versus transarterial chemoembolization (TACE) for stage T3 HCC. METHODS: From 2005 to 2013, 1179 patients with T3 HCC who underwent HR or TACE were divided into two groups, HR group (n = 280) or TACE group (n = 899). The clinical outcomes were compared before and after propensity score matching. RESULTS: The propensity model matched 244 patients in each group for further analyses. After matching, medium overall survival (OS), 1, 3, and 5-year OS rates in TACE group were 11.8 (95%CI, 9.9-13.7) months, 49.6, 16.5, and 8.4%, respectively; which in HR group were 17.8 (95% CI, 14.8-20.8) months, 63.1, 33.3, and 26.4%, respectively; (log rank = 19.908, P < 0.01). Patients in HR group were more likely to develop pleural effusion, compared with those in TACE group (0.4% vs. 5.3%, P = 0.01). However, no significant differences in other adverse events (AEs) were found between two groups. Similar results were also demonstrated prior to the matched analysis. Multivariate analysis indicated that prothrombin time (PT), tumor size, tumor numbers, UICC staging status, and initial treatment were independent prognostic factors. CONCLUSIONS: Our study revealed that TACE was an option for UICC T3 HCC patients. However, HR seemed to be safe and yield a survival benefit compared with TACE, especially for patients with a good underlying liver function.

The Chinese medicine, Jianpi Huayu Decoction, inhibits the epithelial mesenchymal transition via the regulation of the Smad3/Smad7 cascade.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common and aggressive malignant tumors in the world. In China, traditional medicine is commonly used in the treatment of cancer. Among these medicines, Jianpi Huayu Decoction (JHD) is a typical clinical prescription against multiple tumors. However, the exact function and targets of JHD are currently unknown. The aim of this study is to assess the efficacy of JHD against HCC. METHODS AND RESULTS: Hepatic carcinoma SMMC7221 cells were treated with JHD drug-serum in a dose- and time-dependent manner. Real-time PCR (RT-PCR), western-blot (WB), and immunofluorescence microscopy revealed that JHD increased both the mRNA and protein levels of Smad7 and decreased the protein level of p-Smad3. It subsequently increased the E-cadherin expression level and decreased those of N-cadherin and Vimentin. Metastasis and invasion were eventually inhibited, as determined by the wound healing and transwell invasion assays. Treatment of Tanshinone IIA (Tan IIA) showed similar results as JHD, indicating that it is most likely the main functional drug monomer of JHD. The in vivo assay in nude mice also revealed the efficacy of JHD to inhibit epithelial mesenchymal transition (EMT). CONCLUSION: JHD was shown to be an effective therapeutic strategy against HCC.

Hierarchical self-assembly of a fluorescence emission-enhanced organogelator and its multiple stimuli-responsive behaviors.

A discrete hexagonal metallacycle 1 decorated with tetraphenylethylene, amide groups and long hydrophobic alkyl chains was constructed via [3 + 3] coordination-driven self-assembly, from which the fluorescence emission-enhanced organogelator with multiple stimuli-responsiveness was successfully prepared via hierarchical self-assembly.

A selective fluorescent probe for the detection of Cd(2+) in different buffer solutions and water.

A simple fluorescent probe NHQ based on quinoline was successfully prepared via one-step synthesis. The probe NHQ exhibited "turn-on" fluorescence and excellent selectivity toward Cd(2+) in different buffer solutions such as Tris-HCl buffer solution, HEPES buffer solution, and PBS buffer solution, and even in water. Moreover, the binding model of NHQ with Cd(2+) was definitely confirmed by the single crystal X-ray diffraction studies of the complex.

A neutral branched platinum-acetylide complex possessing a tetraphenylethylene core: preparation of a luminescent organometallic gelator and its unexpected spectroscopic behaviour during sol-to-gel transition.

A neutral branched platinum-acetylide complex TPA possessing a tetraphenylethylene core was successfully prepared, which was found to form luminescent organometallic gels in ethyl acetate. Stimulated by temperature or F(-), the reversible gel-sol transition was realized. More interestingly, TPA exhibited an unexpected blue shift of the emission during the sol-to-gel transition.

A naphthalimide-based fluorescence "turn-on" probe for the detection of Pb(2+) in aqueous solution and living cells.

An easily available naphthalimide-based fluorescent probe NPA for Pb(2+) detection was successfully developed. NPA exhibited an obvious fluorescence turn-on response toward Pb(2+) in aqueous solution and in living cells. Moreover, a series of model compounds were rationally designed and synthesized in order to explore the sensing mechanism and binding mode of NPA with Pb(2+) .