Palladium-Catalyzed Selective γ-Monoarylation of Free Amines Containing Symmetric γ-C-H Controlled by a Transient Directing Group.

We developed a new transient directing group, N-(2-benzoyl-4-chlorophenyl)-1,1,1-trifluoromethanesulfonamide, which can facilitate the γ-monoarylation of free amines containing symmetric γ-C-H bonds. A variety of amines containing symmetric and identical γ-C(sp3)-H and γ-C(sp2)-H reacted with a diverse range of aryl and heteroaryl iodides to provide γ-monoarylated products exclusively.

CTBP2 contributes to cisplatin resistance in lung adenocarcinoma by inhibiting generation of reactive oxygen species.

Background: Cisplatin (CP) is commonly used for the initial treatment of lung adenocarcinoma (LUAD). Resistance to CP has long been recognized as a significant obstacle to achieving improved therapeutic outcomes. Nevertheless, the intricate molecular mechanisms underlying the phenomenon remain incompletely understood. Methods: The present study utilized the University of ALabama at Birmingham CANcer data analysis Portal (UALCAN) and Gene Expression Profiling Interactive Analysis (GEPIA) databases to conduct an analysis of the expression of C-terminal binding protein 2 (CTBP2) in LUAD. The correlation between CTBP2 expression and survival data was investigated by the Kaplan-Meier (K-M) plotter. Subsequently, the roles of CTBP2 in CP resistance were explored by analyzing cell viability, cell apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) in CP-resistant cells (A549/DDP). Results: Our data indicated that the CTBP2 expression in LUAD exhibited a significant increase compared to the non-malignant tissues. CTBP2 overexpression showed a correlation to poor survival. CTBP2 knockdown significantly enhanced cell sensitivity to CP in A549/DDP cells. The underlying mechanism is related to promoting ROS production and decreasing MMP after CP treatment. Conclusions: CTBP2 expression has been identified as a novel biomarker for resistance to CP, and its downregulation has been found to enhance sensitivity to CP. Therefore, CTBP2 can serve as a predictor related to CP resistance and a viable therapeutic target for CP resistance in LUAD.

LiOtBu-Promoted trans-Stereoselective and ß-Regioselective Hydroboration of Propargyl Alcohols.

A convenient and efficient trans-stereoselective and ß-regioselective hydroboration of propargyl alcohols was achieved simply with LiOtBu as the base and (Bpin)2 as the boron reagent in dimethyl sulfoxide at room temperature. Both terminal and internal propargyl alcohols with diverse structures and functional groups underwent the transformation smoothly to produce ß-Bpin-substituted (E)-allylic alcohols, of which the synthetic potentials were demonstrated by the downstream conversions of boronate, alkenyl, and hydroxyl groups.

The complete mitochondrial genome of Thereuopoda clunifera (Chilopoda: Scutigeridae) and phylogenetic implications within Chilopoda.

We determined the complete mitochondrial genome of Thereuopoda clunifera (Chilopoda: Scutigeridae) to clarify the phylogenetic status within Chilopoda. Using Sanger sequencing and next-generation sequencing technologies, the entire mitogenome of T. clunifera was assembled and annotated, with 14,898 bp in length and 37 genes (13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes), which are usually found in arthropod mitogenomes. Only one D-loop contained no repeat element. The base composition of T. clunifera was found to be A + T content of 69.55% and G + C content of 30.45%. The AT-skew of T. clunifera was positive, while the GC-skew was negative. The gene order of T. clunifera was identical to that of Scutigera coleoptrata that has been unique among those so far determined for the Arthropoda. We also performed phylogenetic analyses of 25 Myriapoda species to further explore the taxonomic and evolutionary relationships within Myriapoda and Chilopoda. Phylogenetic analyses supported that the division of Chilopoda into subclasses Notostigmophora and Pleurostigmophora.

Stereoselective Dehydroxyboration of Allylic Alcohols to Access (E)-Allylboronates by a Combination of C-OH Cleavage and Boron Transfer under Iron Catalysis.

Iron-catalyzed direct SN2' dehydroxyboration of allylic alcohols has been developed to access (E)-stereoselective allylboronates. Allylic alcohols with diverse structures and functional groups, especially derived from natural products, underwent smooth transformation. The six-membered ring transition state formed by allylic alcohols and iron-boron intermediate was indicated to be the key component involved in transfer of the boron group, activation of the C-OH bond, and control of the stereoselectivity.

The complete plastid genome sequence of Ilex suaveolens (H. Lév.) Loes, the most abundant medicinal holly in Mount Huangshan.

Holly (Ilex L.) is a woody dioecious genus cultivated as pharmaceutical, ornamentals, and industrial materials. Ilex suaveolens (H. Lév.) Loes is an endemic medicinal holly with a predominant distribution in Mount Huangshan, China. In the present work, the complete plastid genome of I. suaveolens was de novo sequenced by high-throughput sequencing technology. The newly-assembled plastid genome holds 37.6% of the overall GC content and a length of 157,857 bp, comprising a large single-copy (LSC, 87,255 bp), a small single-copy (SSC, 18,398 bp), and a pair of inverted repeat (IRs, 26,102 bp) regions. The plastid genome annotation suggested the presence of a total of 89 protein-encoding genes, 37 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes. The plastome-mediated phylogenetic topology revealed that I. suaveolens clustered together with I. szechwanenesis and I. viridis in the same clade, and a strong relationship between clades and biogeography was found. These data contribute to the understanding of genetic diversity and conservation study of Ilex in Mount Huangshan.

Long non-coding maternally expressed gene 3 regulates cigarette smoke extract-induced apoptosis, inflammation and cytotoxicity by sponging miR-181a-2-3p in 16HBE cells.

Accumulating evidence has suggested that long non-coding (lnc)RNAs are widely involved in the progression of multiple diseases, including chronic obstructive pulmonary disease (COPD). The aim of the present study was to explore the function and molecule mechanism of maternally expressed gene 3 (MEG3) in cigarette smoke extract (CSE)-treated 16HBE cells. Cell viability and apoptosis were evaluated using Cell Counting Kit-8 analysis and flow cytometry, respectively. Western blot analysis was carried out to determine the protein levels of Bcl-2, Bax and cleaved caspase-3. ELISA assays were utilized to measure the protein levels of IL-1ß and IL-6 and TNF-α. Cytotoxicity was assessed using a lactate dehydrogenase release assay. The expression levels of MEG3 and microRNA (miR)-181a-2-3p were detected using reverse transcription-quantitative PCR. The interaction between miR-181a-2-3p and MEG3 was predicted using DIANA tools and verified by a dual-luciferase reporter assay and RNA Immunoprecipitation assay. MEG3 expression was enhanced while miR-181a-2-3p abundance was reduced in the serum of patients with COPD and CSE-treated 16HBE cells. MEG3-knockdown or miR-181a-2-3p-overexpression inhibited CSE-induced apoptosis, inflammation and cytotoxicity in 16HBE cells. Moreover, miR-181a-2-3p directly bind to MEG3 and its knockdown reversed the inhibitory effect of MEG3 interference on apoptosis, inflammation and cytotoxicity in CSE-treated 16HBE cells. Overall, MEG3-knockdown suppressed CSE-induced apoptosis, inflammation and cytotoxicity in 16HBE cells by upregulating miR-181a-2-3p, providing a promising therapeutic target for treatment of CSE-induced COPD.

Distinct Features of Gut Microbiota in High-Altitude Tibetan and Middle-Altitude Han Hypertensive Patients.

Indigenous animals show unique gut microbiota (GM) in the Tibetan plateau. However, it is unknown whether the hypertensive indigenous people in plateau also have the distinct gut bacteria, different from those living in plains. We sequenced the V3-V4 region of the gut bacteria 16S ribosomal RNA (rRNA) gene of feces samples among hypertensive patients (HPs) and healthy individuals (HIs) from 3 distinct altitudes: Tibetans from high altitude (3600-4500 m, n = 38 and 34), Hans from middle altitude (2260 m, n = 49 and 35), and Hans from low altitude (13 m, n = 34 and 35) and then analyzed the GM composition among hypertensive and healthy subgroups using the bioinformatics analysis, respectively. The GM of high-altitude Tibetan and middle-altitude Han HPs presented greater α- and ß-diversities, lower ratio of Firmicutes/Bacteroidetes (F/B), and higher abundance of beneficial Verrucomicrobia and Akkermansia than the low-altitudes HPs did. The GM of high-altitude Tibetan and middle-altitude HIs showed greater α-diversity and lower ratio of F/B than the low-altitudes HIs did. But, ß-diversity and abundance of Verrucomicrobia and Akkermansia among different subgroups of HIs did not show any differences. Conclusively, the high-altitude Tibetan and middle-altitude Han HPs have a distinct feature of GM, which may be important in their adaptation to hypertension in the plateau environments.

Residual characteristics and potential health risk assessment of polychlorinated biphenyls (PCBs) in seafood and surface sediments from Xiangshan Bay, China (2011-2016).

Xiangshan Bay provides most of the seafood for residents from the southeast coast of China. However, information on the safety of local seafood was not well known. In this study, we investigated the residue, spatial distribution and potential health risks of ten polychlorinated biphenyls (PCBs) in seafood and surface sediment samples during six years (2011-2016). The results indicated the level of PCBs in 9 types of seafood from Xiangshan Bay ranged between ND and 25.3 ng·g-1. The highest average concentration of PCBs (14.2 ng·g-1) was observed in Ostreidae. The average PCB concentrations in the surface sediments was 1.58 ng·g-1 (ND to 15.2 ng·g-1). The biota-sediment accumulation factors of the PCBs in most seafood indicated that the seafood was readily subjected to the bioaccumulation of PCBs from sediments. The carcinogenic risks were all within the safe ranges of 9 types of seafood for adults.

Preclinical pharmacokinetics, disposition, and translational pharmacokinetic/pharmacodynamic modeling of savolitinib, a novel selective cMet inhibitor.

Savolitinib is a novel small-molecule selective cMet inhibitor. This work characterized its pharmacokinetics in preclinical phase, established the preclinical relationships between PK, cMet modulation and anti-tumor efficacy. In vitro and in vivo animal studies were performed for PK characterization. Savolitinib showed good absorption, moderate tissue distribution, low to intermediate clearance, and low accumulation. Hepatic oxidative metabolism followed by urinary and biliary excretions was the major elimination pathway. Based on preclinical PK data, human PK profiles were predicted using empirical methods. Pharmacodynamic studies for evaluating cMet inhibition and anti-tumor efficacy were conducted in nude mice bearing Hs746t xenograft. PK/PD models were built to link the PD measurements to nude mouse PK. The established integrated preclinical PK/PD model contained a two-compartment non-linear PK model, a biomarker link model and a tumor growth transit model. The IC50 of cMet inhibition and the concentration achieving half of the maximal Hs746t tumor reduction by savolitinib were equal to 12.5 and 3.7 nM (free drug), respectively. Based on the predicted human PK data, as well as the established PK/PD model in nude mouse, the human PD (cMet inhibition) profiles were also simulated. This research supported clinical development of savolitinib. Understanding the preclinical PK/PD relationship of savolitinib provides translational insights into the cMet-targeted drug development.

A LY-15, a novel cyclic pentapeptide that inhibits B16 cell proliferation and migration and induces cell apoptosis.

Melanoma is highly resistant to most traditional treatments; therefore, its incidence and mortality rates are rapidly increasing. The effect of a novel sansalvamide A analogue named LY-15 on the growth and induction of apoptosis in B16 cancer cells was investigated in vitro. The inhibitory effects of LY-15 on B16 cells occurred in a concentration- and time-dependent manner. The B16 cells were cultured in various concentrations of LY-15 (5, 15 and 25 µM), and the ameliorating effect of LY-15 was evaluated using apoptotic protein markers B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase-3 and caspase-9. Furthermore, LY-15 effectively inhibited the B16 cell migration, increased the expressions levels of caspase-3, caspase-9 and the pro-apoptotic Bax, and reduced that of the anti-apoptotic Bcl-2. These findings suggested that LY-15 is a promising chemotherapeutic agent against melanoma by inducing apoptosis through the mitochondrial-associated death pathway. In addition, sansalvamide A analogue LY-15 may a significant therapeutic target for the treatment of malignant melanoma cancer.

Anti-tumor efficacy of theliatinib in esophageal cancer patient-derived xenografts models with epidermal growth factor receptor (EGFR) overexpression and gene amplification.

Targeted therapy is not yet approved for esophageal cancer (EC). In this study, we first evaluated EGFR gene and protein expression in 70 Chinese EC patient tumor samples collected during surgery. We then established 23 patient-derived EC xenograft (PDECX) models and assessed the efficacy of theliatinib, a potent and highly selective EGFR inhibitor currently in Phase I clinical study, in 9 PDECX models exhibiting various EGFR expression levels. Immunohistochemical analysis showed that 50 patient tumor samples (71.4%) had high EGFR expression. Quantitative PCR showed that eight tumors (11.6%) had EGFR gene copy number gain, and fluorescence in situ hybridization (FISH) revealed that four tumors had EGFR gene amplification. These results suggest that EGFR protein may be overexpressed in many EC tumors without gene amplification. Also detected were rare hot-spot mutations in EGFR and PIK3CA, whereas no mutations were found in K-Ras or B-Raf. Theliatinib exhibited strong antitumor activity in PDECX models with high EGFR expression, including remarkable tumor regression in two PDECX models with both EGFR gene amplification and protein overexpression. However, the efficacy of theliatinib was diminished in models with PI3KCA mutations or FGFR1 overexpression in addition to high EGFR expression. This study demonstrates that theliatinib could potentially benefit EC patients with high EGFR protein expression without mutations or aberrant activities of associated factors, such as PI3KCA or FGFR1.

Temperature-Dependent Enantio- and Diastereodivergent Synthesis of Amino Acids with One or Multiple Chiral Centers.

A general and facile methodology for temperature-dependent enantiodivergent and diastereodivergent synthesis of amino acids with one or multiple chiral centers was developed. Camphor-based tricyclic iminolactones attack electrophiles from the endo face at low temperature (-78 to -40 °C) and from the exo face at high temperature (-10 to 25 °C).

Synthesis and activity evaluation of the cyclic dipeptides arylidene N-alkoxydiketopiperazines.

A series of arylidene N-alkoxydiketopiperazines was designed and stereoselectively synthesized via oxime-ether formation and intramolecular acylation. Possible cyclization and acid-catalyzed rearrangement-fragmentation mechanisms were discussed. The crystal structure of the novel diketopiperazine further confirmed the rearrangement mechanism. Most compounds exhibited antitumor activity. Several compounds were more potent against caspase-3. Specifically, compounds 6e, 6g, and 6f inhibited caspase-3 at IC50 values lying within the low micromolar range and demonstrated good selectivity. The binding modes of alkoxydiketopiperazines in the active center of caspase-3 were also discussed based on the molecular docking results.

[Study on UHPLC fingerprint and determination of eight phenolic components of Tetrastigma hemsleyanum leaves].

A novel method combining ultra-high performance liquid chromatography (UHPLC) fingerprint and simultaneous quantitative analysis of eight phenolic components was developed and validated for quality evaluation of Tetrastigma hemsleyanum leaves. For fingerprint analysis, 15 peaks were selected as the common peaks to evaluate the similarities among 41 batches of T. hemsleyanum leaves collected from different regions. Additionally, simultaneous quantification of eight markers, including neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, isoorientin, orientin, vitexin-2-O-rhamnoside,vitexin and isovitexin, was performed and the obtained data demonstrated that our method has achieved desired linearity, precision and accuracy. Clustering statistical analysis was further application in T. hemsleyanum leaves from different regions. The results indicated that new approach conbine ultra-high performance liquid chromatography (UHPLC) fingerprint and simultaneous quantitative analysis of eight phenolic components was applicable in quality control of T. hemsleyanum leaves.

[Investigation on resource and quality assessment of Cibotii Rhizoma].

The study is aimed to understand the resource and the current situation of the use of Cibotii Rhizoma and provide the basis for protecting and utilization. The method of literature survey, field survey and quality assessment were applied in the study. The results showed that all the Cibotii Rhizoma came from wild resource and was mainly founded in Fujian, Guangxi, Guizhou, Yunnan, Guangdong, Hunan, Jiangxi, Sichuan, Chongqing, Zhejiang, etc. It contains over 5 000 000 kg in the area which total is about 7 000 hm2. The annual output is over 850 000 kg. At present, there is no cultivated resources. Based on the investigation and market sampling analysis from various regions, the results showed that the quality of the collected crude drugs conformed with the regulations of the Chinese pharmacopoeia. However the qualification rate of decoction pieces of Cibotii Rhizoma in market was only 56.4%. At present, the resource of Cibotii Rhizoma could meet the needs of medinal uses. It is important to protect the wild resource which is less and less because of the environmental factors. It also need to make a standard of processing method to ensure the safety, and solve quality problem of the decoction pieces.

Synthesis and biological evaluation of open-chain analogs of cyclic peptides as inhibitors of cellular Shp2 activity.

A series of open-chain analogs of cyclic peptides was designed and synthesized using sansalvamide A as a model compound. All compounds exhibited low antitumor activity. Furthermore, the evaluation of their inhibitory potency toward IMPDH, SHP2, ACHE, proteasome, MAGL, and cathepsin B showed that all of the compounds were potent against protein tyrosine phosphatase Shp2. Specifically, compounds 1a, 1d, 2b, and 2f were found to inhibit SHP2 with IC50 values in the low micromolar range and good selectivity. Based on the molecular docking results, the binding modes of the chain cyclic peptides in the active center of SHP2 were discussed.

Volitinib, a potent and highly selective c-Met inhibitor, effectively blocks c-Met signaling and growth in c-MET amplified gastric cancer patient-derived tumor xenograft models.

PURPOSE: To investigate the incidence of cMET gene copy number changes and protein overexpression in Chinese gastric cancer (GC) and to preclinically test the hypothesis that the novel, potent and selective cMET small-molecule inhibitor volitinib, will deliver potent anti-tumor activity in cMET-dysregulated GC patient-derived tumor xenograft (PDX) models. EXPERIMENTAL DESIGN: A range of assays were used and included; in vitro cell line panel screening and pharmacodynamic (PD) analysis, cMET fluorescence in-situ hybridization (FISH) and immunohistochemical (IHC) tissue microarray (TMA) analysis of Chinese GC (n = 170), and anti-tumor efficacy testing and PD analysis of gastric PDX models using volitinib. RESULTS: The incidence of cMET gene amplification and protein overexpression within Chinese patient GC tumors was 6% and 13%, respectively. Volitinib displayed a highly selective profile across a gastric cell line panel, potently inhibiting cell growth only in those lines with dysregulated cMET (EC50 values 0.6 nM/L-12.5 nM/L). Volitinib treatment led to pharmacodynamic modulation of cMET signaling and potent tumor stasis in 3/3 cMET-dysregulated GC PDX models, but had negligible activity in a GC control model. CONCLUSIONS: This study provides an assessment of tumor cMET gene copy number changes and protein overexpression incidence in a cohort of Chinese GC patients. To our knowledge, this is the first study to demonstrate anti-tumor efficacy in a panel of cMET-dysregulated gastric cancer PDX models, using a novel selective cMET-inhibitor (volitinib). Thus, the translational science presented here provides strong rationale for the investigation of volitinib as a therapeutic option for patients with GC tumors harboring amplified cMET.

Discovery of (S)-1-(1-(Imidazo[1,2-a]pyridin-6-yl)ethyl)-6-(1-methyl-1H-pyrazol-4-yl)-1H-[1,2,3]triazolo[4,5-b]pyrazine (volitinib) as a highly potent and selective mesenchymal-epithelial transition factor (c-Met) inhibitor in clinical development for treatment of cancer.

HGF/c-Met signaling has been implicated in human cancers. Herein we describe the invention of a series of novel triazolopyrazine c-Met inhibitors. The structure-activity relationship of these compounds was investigated, leading to the identification of compound 28, which demonstrated favorable pharmacokinetic properties in mice and good antitumor activities in the human glioma xenograft model in athymic nude mice.

[Separation and Quantitative Determination of Four Flavonoids in Tetrastigma hemsleyanum].

OBJECTIVE: To develop a method for separation and quantitative determination of four flavonoids in Tetrastigma hemsleyanum. METHODS: The Separation was performed on a Waters Preparative scale LC-MS autopurification system. Several spectral analyses, such as NMR,HR-MS and UV were used to identify the chemical structures. Quantitative assay was performed on a UHPLC Phenomenex Kinetex C18 column (100 mm x 4.6 mm, 2.6 µm) with the mobile phase consisting of acetonitrile( B) and water containing 0. 1% formic acid (A) in a gradient mode at a flow rate of 0.4 mL/min. The column temperature was at 30 °C and the optimum detection wavelength of DAD was set at 350 nm. RESULTS: Four flavonoids were isolated from the root of Tetrastigma hemsleyanum, which were identified as rutin, isoquercitrin, kaempferol-3-O-rutinoside and astragalin. As to quantitative analysis, a good separation of four flavonoids with in 17.5 min, the linear range of rutin, isoquercitrin, kaempferol-3-O-rutinoside and astragalin was 0.283-11.32 µg/mL (r1 = 0.9998), 0.311-12.44 µg/mL (r2 = 0.9994), 0.277-11.08 µg/mL (r3 = 0.9995) and 0.103-2.06 µg/mL (r4 = 0.9990), respectively. The average recovery (n = 6) was 99.75% (RSD = 2.15%), 98.73% (RSD = 2.58%) ,98. 03% (RSD = 2.23%), and 97.62% (RSD = 1.95%), respectively. CONCLUSION: Four flavonoids are isolated from the root of Tetrastigma hemsleyanum for the first time, and the UHPLC method is simple, rapid and accurate, which can be used for quantitative analysis of multi-component of Tetrastigma hemsleyanum and provide a novel approach for evaluation of the quality of Tetrastigma hemsleyanum comprehensively.