Total Synthesis of abeo-Steroids via Cycloaddition Strategy.

ConspectusSteroids continue to play a significant role in organic chemistry, medicinal chemistry, and drug discovery due to their important biological activities and diverse intriguing structures. Although synthetic organic chemists have successfully constructed and elaborated the classical [6-6-6-5] tetracyclic steroid skeleton for nearly a century, synthesis of the unusual rearranged steroids, particularly abeo-steroids with a medium-sized ring, remains a challenge in the synthetic community. Furthermore, the structures of abeo-steroids are complex and diverse, containing a seven-membered ring embedded in the fused or bridged A/B ring system and possessing numerous stereogenic centers. Besides their structural complexity, various abeo-steroids have shown remarkable biological activities. However, the relative scarcity of abeo-steroids in natural sources has impeded the systematic evaluation of their biological activities. In addition, direct strategies to build the core structures of abeo-steroids are very rare, partially because of the high ring-strain energies of their rearranged A/B ring systems. Therefore, the development of direct and efficient synthetic approaches to these complex molecules is highly desired.Our long-standing interest in the total synthesis of abeo-steroids and the development of new cycloaddition reactions for streamlining complex molecule synthesis have led us to develop a series of unique and powerful intramolecular cycloaddition strategies to access a diverse array of highly strained abeo-steroids. These strategies include Ru-catalyzed [5 + 2] cycloaddition, acid-promoted type I [5 + 2] cycloaddition, Rh-catalyzed [2 + 2 + 1] cycloaddition, and type II [5 + 2] cycloaddition. Since 2018, we have accomplished the first total syntheses of five synthetically challenging abeo-steroids, i.e., bufogargarizins A and B, phomarol, bufospirostenin A, and cyclocitrinol, thus facilitating the evaluation of their pharmacological potentials. In this Account, we summarize our laboratory's systematic efforts in the total synthesis of these abeo-steroids via cycloaddition strategies. We highlight the efficiency and versatility of each cycloaddition strategy for constructing structurally complex abeo-steroid cores by forming the A/B ring system. The evolution of each strategy and key lessons learned from the synthetic journey are also discussed. We believe that our unique perspective in this field will promote advances in the total synthesis of abeo- and related steroids.

Asymmetric Total Synthesis of Twin Bufogargarizins A and B.

The first and asymmetric total synthesis of bufogargarizins A and B, two unusual and highly oxygenated twin steroids with rearranged A/B rings, was achieved. The synthetically challenging [7-5-6-5] tetracyclic ring system of bufogargarizin A was efficiently constructed by the first intramolecular Ru-catalyzed [5 + 2] cycloaddition reaction of a vinyl ether cyclopropane-yne. Notably, the interesting [5-7-6-5] tetracyclic skeleton of bufogargarizin B was diastereoselectively reassembled by unique retro-aldol/transannular aldol cascade reactions from the [7-5-6-5] tetracyclic framework.

Analysis of N6-Methyladenosine RNA Methylation Regulators in Diagnosis and Distinct Molecular Subtypes of Ankylosing Spondylitis.

The most frequent internal modification in eukaryotic mRNA is N6-methyladenosine (m6A). However, what we know about the m6A regulators in Ankylosing spondylitis (AS) is still limited. In our study, eight distinct m6A regulators were selected utilizing Differentially Expressed Gene (DEG) analysis of the Gene Expression Omnibus GSE73754 dataset for making comparisons between AS (Ankylosing spondylitis) and non-AS patients. The random forest model and the nomogram model were used to screen the eight candidate m6A regulators and evaluate their prediction accuracy for the occurrence of AS. Furthermore, based on the selected m6A regulators, the AS patients were divided into two subgroups, and we applied principal component analysis algorithms to calculate their m6A score and evaluate the m6A patterns. Our findings revealed that patients in cluster A were linked to activated CD4 T cell immunity and activated CD8 T cell immunity. With its major contributions in the area of immunology, our research in m6A patterns may benefit the future diagnosis and treatment strategies of AS.

Targeting neuropilin-1 interactions is a promising anti-tumor strategy.

ABSTRACT: Neuropilins (NRP1 and NRP2) are multifunctional receptor proteins that are involved in nerve, blood vessel, and tumor development. NRP1 was first found to be expressed in neurons, but subsequent studies have demonstrated its surface expression in cells from the endothelium and lymph nodes. NRP1 has been demonstrated to be involved in the occurrence and development of a variety of cancers. NRP1 interacts with various cytokines, such as vascular endothelial growth factor family and its receptor and transforming growth factor ß1 and its receptor, to affect tumor angiogenesis, tumor proliferation, and migration. In addition, NRP1+ regulatory T cells (Tregs) play an inhibitory role in tumor immunity. High numbers of NRP1+ Tregs were associated with cancer prognosis. Targeting NRP1 has shown promise, and antagonists against NRP1 have had therapeutic efficacy in preliminary clinical studies. NRP1 treatment modalities using nanomaterials, targeted drugs, oncolytic viruses, and radio-chemotherapy have gradually been developed. Hence, we reviewed the use of NRP1 in the context of tumorigenesis, progression, and treatment.

Asymmetric Total Synthesis of Bufospirostenin A.

The first and asymmetric total synthesis of bioactive bufospirostenin A, an unusual spirostanol with rearranged A/B rings, was accomplished. The synthetically challenging [5-7-6-5] tetracyclic ring system, found in bufospirostenin A and some other natural products, was efficiently constructed by the unique intramolecular rhodium-catalyzed Pauson-Khand reaction of an alkoxyallene-yne. The 11 stereocenters in the final product, including the 10 contiguous stereocenters, were installed diastereoselectively.

Unusual KIE and dynamics effects in the Fe-catalyzed hetero-Diels-Alder reaction of unactivated aldehydes and dienes.

Hetero-Diels-Alder (HDA) reaction is an important synthetic method for many natural products. An iron(III) catalyst was developed to catalyze the challenging HDA reaction of unactivated aldehydes and dienes with high selectivity. Here we report extensive density-functional theory (DFT) calculations and molecular dynamics simulations that show effects of iron (including its coordinate mode and/or spin state) on the dynamics of this reaction: considerably enhancing dynamically stepwise process, broadening entrance channel and narrowing exit channel from concerted asynchronous transition states. Also, our combined computational and experimental secondary KIE studies reveal unexpectedly large KIE values for the five-coordinate pathway even with considerable C-C bond forming, due to equilibrium isotope effect from the change in the metal coordination. Moreover, steric and electronic effects are computationally shown to dictate the C=O chemoselectivity for an α,ß-unsaturated aldehyde, which is verified experimentally. Our mechanistic study may help design homogeneous, heterogeneous and biological catalysts for this challenging reaction.

Application of Newcastle disease virus in the treatment of colorectal cancer.

Colorectal cancer (CRC) is one of the main reasons of tumor-related deaths worldwide. At present, the main treatment is surgery, but the results are unsatisfactory, and the prognosis is poor. The majority of patients die due to liver or lung metastasis or recurrence. In recent years, great progress has been made in the field of tumor gene therapy, providing a new treatment for combating CRC. As oncolytic viruses selectively replicate almost exclusively in the cytoplasm of tumor cells and do not require integration into the host genome, they are safer, more effective and more attractive as oncolytic agents. Newcastle disease virus (NDV) is a natural RNA oncolytic virus. After NDV selectively infects tumor cells, the immune response induced by NDV's envelope protein and intracellular factors can effectively kill the tumor without affecting normal cells. Reverse genetic techniques make NDV a vector for gene therapy. Arming the virus by inserting various exogenous genes or using NDV in combination with immunotherapy can also improve the anti-CRC capacity of NDV, and good results have been achieved in animal models and clinical treatment trials. This article reviews the molecular biological characteristics and oncolytic mechanism of NDV and discusses in vitro and in vivo experiments on NDV anti-CRC capacity and clinical treatment. In conclusion, NDV is an excellent candidate for cancer treatment, but more preclinical studies and clinical trials are needed to ensure its safety and efficacy.

Screening of aptamers and their potential application in targeted diagnosis and therapy of liver cancer.

Aptamers are a class of single oligonucleotide molecules (DNA or RNA) that are screened from random DNA or RNA oligonucleotide chain libraries by the systemic evolution of ligands by exponential enrichment technology. The selected aptamers are capable of specifically binding to different targeting molecules, which is achieved by the three-dimensional structure of aptamers. Aptamers are similar in function to monoclonal antibodies, and therefore, they are also referred to as "chemical antibodies". Due to their high affinity and specificity and low immunogenicity, aptamers are topics of intense interest in today's biological targeting research especially in tumor research. They not only have high potential for clinical advances in tumor targeting detection but also are highly promising as targeted tumor drug carriers for use in tumor therapy. Various experimental studies have shown that aptamer-based diagnostic and therapeutic methods for liver cancer have great potential for application. This paper summarizes the structure, characteristics, and screening methods of aptamers and reviews the recent research progress on nucleic acid aptamers in the targeted diagnosis and treatment of liver cancer.

Isolation, Structure Elucidation, and Total Synthesis of Myrtuspirone A from Myrtus communis.

A pair of enantiomeric triketone-phloroglucinol hybrids, (+)- and (-)-myrtuspirone A (1), featuring an unprecedented 3-isopropyl-3 H-spiro[benzofuran-2,1'-cyclohexane] backbone, were isolated from the leaves of Myrtus communis. The absolute configuration of each enantiomer of 1 was determined by X-ray diffraction and chemical calculations. Furthermore, the gram-scale total syntheses of (±)-1 and (-)-1 were conducted in four steps using a Michael- N-iodosuccinimide (NIS)-mediated (3 + 2)-annulation reaction. Both (+)- and (-)-1 exhibited antibacterial activities against Gram-positive bacteria including multidrug-resistant strains.

APC-activated long noncoding RNA inhibits colorectal carcinoma pathogenesis through reduction of exosome production.

The adenomatous polyposis coli (APC) gene plays a pivotal role in the pathogenesis of colorectal carcinoma (CRC) but remains a challenge for drug development. Long noncoding RNAs (lncRNAs) are invaluable in identifying cancer pathologies and providing therapeutic options for patients with cancer. Here, we identified a lncRNA (lncRNA-APC1) activated by APC through lncRNA microarray screening and examined its expression in a large cohort of CRC tissues. A decrease in lncRNA-APC1 expression was positively associated with lymph node and/or distant metastasis, a more advanced clinical stage, as well as a poor prognosis for patients with CRC. Additionally, APC could enhance lncRNA-APC1 expression by suppressing the enrichment of PPARα on the lncRNA-APC1 promoter. Furthermore, enforced lncRNA-APC1 expression was sufficient to inhibit CRC cell growth, metastasis, and tumor angiogenesis by suppressing exosome production through the direct binding of Rab5b mRNA and a reduction of its stability. Importantly, exosomes derived from lncRNA-APC1-silenced CRC cells promoted angiogenesis by activating the MAPK pathway in endothelial cells, and, moreover, exosomal Wnt1 largely enhanced CRC cell proliferation and migration through noncanonicial Wnt signaling. Collectively, lncRNA-APC1 is a critical lncRNA regulated by APC in the pathogenesis of CRC. Our findings suggest that an APC-regulated lncRNA-APC1 program is an exploitable therapeutic approach for the treatment of patients with CRC.

Catalytic asymmetric total syntheses of myrtucommuacetalone, myrtucommuacetalone B, and callistrilones A, C, D and E.

Herein, we describe a concise catalytic approach to the first asymmetric total syntheses of myrtucommuacetalone, myrtucommuacetalone B, and callistrilones A, C, D and E. The syntheses proceed in only 5-7 steps from the readily available compound 11, without the need for protecting groups. Key features of the syntheses include a unique organocatalytic asymmetric Friedel-Crafts-type Michael addition with high enantioselectivity and a broad substrate scope, a novel Michael-ketalization-annulation cascade reaction, and an oxidative [3 + 2] cycloaddition. Furthermore, the new compound 7 exhibited potent antibacterial activities against several multidrug-resistant strains (MRSA, VISA and VRE), and showed greater potency than vancomycin.

Efficacy and safety of thrombopoietin receptor agonists in children with chronic immune thrombocytopenia: a meta-analysis.

BACKGROUND AND AIM: Thrombopoietin receptor agonists (TPO-RAs) have been shown to be safe and effective for adults with chronic immune thrombocytopenia (ITP). The aim of this meta-analysis is to assess the efficacy and safety of thrombopoietin receptor agonists for children with chronic ITP. MATERIALS AND METHODS: Clinical randomized controlled trials (RCTs) evaluating the efficacy and safety of TPO-RAs in pediatric ITP patients published up to June 2017 were retrieved from PubMed, Cochrane Library, and Embase databases. Relevant data were extracted, and the Physiotherapy Evidence Database scale was used to assess the methodological quality. Stata/SE 12.0 was used to perform a meta-analysis. RESULTS: Seven RCTs were included, with 238 patients and 107 patients in the TPO-RA group and the control group, respectively. Assessing efficacy, better results were found in the TPO-RA group for the rate of overall platelet response, durable response, and rescue medication needed. Furthermore, the TPO-RA group yielded superior results in the incidence of clinically significant bleeding events but had a comparable result in the incidence of any bleeding events and severe bleeding events. No significant difference was found between the two groups in health-related quality of life and parental burden. Assessing safety, no significant difference was found between the two groups in the incidence of any adverse events and severe adverse events. CONCLUSIONS: TPO-RAs are effective and safe agents for the treatment of chronic ITP in pediatric patients. Eltrombopag appears to be better than romiplostim in terms of the rate of rescue medication needed and clinically significant bleeding events.

[Protective effect and underlying mechanism of cordycepin on non-alcoholic fatty liver in ob/ob mice].

This study is designed to investigate the protective effect and mechanism of cordycepin on non- alcoholic fatty liver in ob/ob mice. Twelve-week-old male ob/ob mice were divided into 5 groups according to their body weight and blood glucose, and C57BL/6J mice were used in the control group. The animals were orally administered with cordycepin for 7 weeks. Body weight and food intake were measured once a week. Blood were collected from ophthalmic venous and biochemical indexes were determined at the 2nd and 4th week. Insulin tolerance test was performed at the 5th week. After 7 weeks of administration, liver tissues were collected to determine the contents of triglycerides and total cholesterol, and pro-inflammatory cytokines. Liver histology was performed by hematoxylin-eosin and oil-red O staining. Total RNA were extracted from liver tissues and the levels of lipid metabolism-related and inflammation-related genes were detected by real time PCR. Cordycepin effectively reduced the blood lipids level and improved liver function. Nevertheless, it did not improve insulin resistance in ob/ob mice. Cordycepin significantly reduced the contents of triglycerides and cholesterol, and the levels of pro-inflammatory cytokines in liver tissues. Moreover, cordycepin remarkably suppressed the expression of genes related to lipids synthesis and inflammation. These results indicate that cordycepin may improve non-alcoholic fatty liver in ob/ob mice, and the underlying mechanism may be associated with decreased expression of genes related to lipids synthesis and inflammation.

[Effect of Kangxianling Recipe on p38MAPK/NF-KBp65 Mediated Inflammatory Factors in 5/6 Nephrectomized Mice].

Objective To observe effects of Kangxianling Recipe ( KXLR) on p38MAPK/NF- κBp65 mediated inflammatory factors in chronic renal failure ( CRF) model mice. Methods Totally 56 C57BL/6J male mice (18 -22 g) were recruited in this experiment. Ten were randomly selected as a sham-operation group. The rest 46 mice were used for preparing CRF model by 5/6 nephrectomization. To- tally 33 successfully modeled mice were divided into the model group, the rapamycin (RAP) group, and the KXLR group according to serum creatinine (SCr) level, 11 in each group. Mice in the RAP group were administered with rapamycin (0.13 mg/100 g per day, 0. 5 mL each time) by gastrogavage. Mice in the KXLR group were administered with KXLR (2 g/100 g per day, 0. 5 mL each time) by gastrogavage. Equal volume of distilled water was administered to mice in the model group and the sham-operation group. Mice were sacrificed after 8 weeks of consecutive medication. The expression of neutrophils was ob- served using immunohistochemical assay. Expression levels of p38MAPK/NF-κB p65 protein and TNF-α/ IL-6 mRNA were detected by Western blot and Real-time PCR. Results Compared with the sham-opera- tion group, the number of positive neutrophils increased, expression levels of p38MAPK/NF-κB p65 protein and TNF-α/IL-6 mRNA were enhanced significantly in the model group (P <0. 05, P <0. 01). Com- pared with the model group, the number of neutrophils was reduced, expression levels of p38MAPK/NF- κB p65 protein and TNF-α/IL-6 mRNA were decreased significantly in the KXLR group and the RAP group (P <0. 05, P <0. 01). RAP showed better effect in decreasing p38MAPK protein expression than KXLR (P <0. 05). There was no statistical difference in the rest indices between the KXLR group and the RAP group (P >0. 05). Conclusions KXLR participated the regulation of p38MAPK/NF-κB p65 mediated in- flammation factors. It had certain improvement in renal fibrosis induced renal failure.

[Antifungal azoles exacerbate vinblastine-related hyponatremia in ALL children].

The purpose of this study was to investigate the clinical characteristics and the treatments of patients with vinblastine-related hyponatremia which was aggravated by azole antifungal agents in children with acute lymphoblastic leukemia(ALL). A total of 93 children treated with vinblastine in our department during April 2013 to March 2014 were enrolled in this study and were divided into 3 groups:VDLD, VDLD with azoles antifungal, VDLD with non azoles antifungal. The incidence and severity of hyponatremia were statistically analysed. The results showed that (1) the incidence of hyponatremia in VDLD group was 93.1%(67/72),100%(13/13) in VDLD with azoles antifungal group, and 75%(6/8) in VDLD with non-azoles antifungal, there was no statistically difference between these three groups. (2) Incidence of moderate to severe hyponatremia (Na<129 mmol/L) in VDLD with azoles antifungal group was(9/13,69.2%),which was significartly higher than those in VDLD group (22/72, 30.6%) and in VDLD with non azoles antifungal group (1/8, 12.5%). However, the difference between VDLD group and VDLD with non azoles antifungal group were not statistical significant. (3) the lowest serum sodium level in VDLD with azoles antifungal group (124.0 ± 8.6 mmol/L) was significantly lower than that in VDLD group (130.8 ± 3.8 mmol/L)and VDLD+non azoles antifungal group(132.9 ± 4.9 mmol/L). Otherwise, the difference was not statistically significant between VDLD group and VDLD with non azoles antifungal group. (4) four children with severe hyponatremia showed convulsions and coma which all belong to VDLD with azoles antifungal group. The children with hyponatremia were restricted intake of fluid, adjusted the liquid tension, supplied hypertonic sodium and given diuretic, the serum sodium value gradually picked up in these children. In 4-11 months' follow-up, no hyponatremia happened again in these children. It is concluded that the incident of hyponatremia in children treated with vinblastine is high, but most of them seldom showed clinical characteristics. The combination of antifungal azoles with vinblastine can increase the incidence and severity of hyponatremia. Therefore, combined administration of azole antifungals with vinblastine should be avoided.

Impulse oscillometry for leukotriene D4 inhalation challenge in asthma.

BACKGROUND: The value of impulse oscillometry (IOS) for bronchial provocation testing is poorly defined. We investigated the positive threshold derived from the parameters and diagnostic power of IOS for asthma with the leukotriene D(4) bronchial provocation test. METHODS: We enrolled 62 subjects with asthma and 21 healthy subjects. IOS was employed to perform the leukotriene D(4) bronchial provocation test, followed by spirometry. The positive threshold was determined based on the cutoff point in the receiver operating characteristic curve, from which the parameters with the highest diagnostic power were obtained. RESULTS: Airway impedance at 5 Hz (Z(5)), resistance at 5 Hz (R(5)), and resonance frequency had the highest diagnostic power (areas under curve 0.82, 0.82, and 0.81, respectively), with increases of 57%, 43%, and 63%, corresponding to a 20% decrease in FEV(1), respectively. IOS indices yielded assay sensitivity and specificity similar to that of spirometry. The positive threshold for IOS, defined as either a 57% increase in Z(5) or a 63% increase in resonance frequency in the bronchial provocation test, yielded an assay accuracy of 0.6 in subjects with asthma. CONCLUSIONS: IOS during the leukotriene D(4) bronchial provocation test has a diagnostic power similar to that of spirometry. Either a 57% increase in Z(5) or a 63% increase in resonance frequency may be regarded as a surrogate of FEV(1) decrease to determine airway hyper-responsiveness in asthma.

[Pulmonary function of children with right lung middle lobe syndrome].

OBJECTIVE: To study the changes of pulmonary function in children with right lung middle lobe syndrome before and after treatment. METHODS: Thirty children with right lung middle lobe syndrome were classified into two age groups: < or =4 years old and >4 years old. Pulmonary function was tested by the 2600-type and the MIR-type pulmonary function spirometry in the < or =4 years and the >4 years age groups, respectively before and after treatment. Terminal flows/peak expiratory flow (25/PF) and the percentage of tidal volume to peak tidal expiratory flow (% V-PF) were measured in the <4 years age group. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) were measured in the >4 years age group. RESULTS: The values of 25/PF and %V-PF in the < or =4 years age group were 0.42+/-0.08 and 0.28+/-0.03, respectively before treatment. The values were improved after treatment (0.58+/-0.12 and 0.39+/-0.06 respectively) (P<0.05). The values of FVC, FEV1 and PEF were 1.75+/-0.32, 1.36+/-0.52 and 2.56+/-0.78, respectively in the >4 years age group before treatment. The values were also improved after treatment (2.37+/-0.78, 2.08+/-0.65 and 3.68+/-0.80 respectively) (P<0.05). CONCLUSIONS: There are significant differences in the pulmonary function before and after treatment in children with right lung middle lobe syndrome. The pulmonary function can return to normal after treatment.