Synthesis of Azetidine Nitrones and Exomethylene Oxazolines through a Copper(I)-Catalyzed 2,3-Rearrangement and 4π-Electrocyclization Cascade Strategy.

A variety of azetidine nitrones are prepared in moderate to good yields through copper(I) combined with 2-aminopyridine to catalyze skeletal rearrangement of O-propargylic oximes. Mechanistic studies reveal that the reaction undergoes a copper(I)-catalyzed tandem [2,3]-rearrangement, 4π-electrocyclization, ring opening, and recyclization over four steps in one pot. Substituents at the terminus of alkyne and oxime moieties have a significant impact on the formation of azetidine nitrones and exomethylene oxazolines, respectively. Furthermore, the obtained azetidine nitrone could easily participate in [3 + 2] cycloaddition with alkynoates, and a [2.2]-paracyclophane-derived azetidine nitrone is synthesized in 45% yield over five steps from bromo[2.2]-paracyclophane.

Exploring the pharmacological effects and potential targets of paeoniflorin on the endometriosis of cold coagulation and blood stasis model rats by ultra-performance liquid chromatography tandem mass spectrometry with a pattern recognition approach.

This study was employed to explore the potential biomarkers of endometriosis of cold coagulation and blood stasis (ECB) model rats and the effective mechanism of action of paeoniflorin (PF). The serum metabolomics approach was carried out using the UPLC-MS technique with a pattern recognition approach to prove the possible biomarkers of the ECB model rats and the perturbed pathways. Subsequently, the mechanism of PF treatment of this disease model was elucidated. The results revealed that the serum metabolism profiles in two groups were also separated significantly. Moreover, 8 biomarkers were found in the positive mode, and 5 biomarkers were found in the negative mode. Totally, 13 biomarkers participated in the metabolism of phenylalanine, arachidonic acid, etc. After treatment with PF, 10 biomarkers were regulated. Among the 10 biomarkers, 4 were statistically significant: l-phenylalanine, l-tryptophan, LysoPC (18:4(6Z,9Z,12Z,15Z)), and LysoPC (16:1(9Z)). We initially confirmed that PF could significantly regulate the metabolic expression of multiple metabolic pathways in the ECB model rats. For the first time, this study explored the mechanism of action of PF treatment based on the metabolic pathways of the organism and demonstrated the potential of the metabolomics techniques for the study of drug action mechanisms.

High-throughput metabolomics used to identify potential therapeutic targets of Guizhi Fuling Wan against endometriosis of cold coagulation and blood stasis.

Metabolomics is an emerging and robust discipline and involves the comprehensive evaluation of small molecule endogenous metabolites and enables the exploration of the pathogenesis of diseases. For example, endometriosis - a common disease which mostly occurs in women of childbearing age. A cure for endometriosis of cold coagulation and blood stasis (ECB) is highly sought after. This study was conducted to discover the potential biomarkers of ECB and the effective mechanism undertaken by Guizhi Fuling Wan (GFW) in treating ECB in rats. Urinary metabolomics were performed by using UPLC-Q-TOF-MS with pattern recognition methods to evaluate the changes in metabolic profiles and to identify biomarkers for elucidating the mechanism of the treatment of ECB with GFW. The results showed that urinary metabolism in the two groups were distinctly separated on the 28th day, and a total of 20 differential biomarkers (16 in the positive mode, 4 in the negative mode) were confirmed involving several key metabolic pathways which included phenylalanine, tyrosine and tryptophan biosynthesis, valine, leucine and isoleucine biosynthesis, glyoxylate and dicarboxylate metabolism, tyrosine metabolism and the citrate cycle. Following the oral administration of GFW, certain pathways were affected; these included the following: phenylalanine, tyrosine and tryptophan biosynthesis, valine, leucine and isoleucine biosynthesis, glyoxylate and dicarboxylate metabolism, tyrosine metabolism, citrate cycle, steroid hormone biosynthesis, tryptophan metabolism, phenylalanine metabolism, primary bile acid biosynthesis, and aminoacyl-tRNA biosynthesis. This study also demonstrated that the administration of GFW affected the levels of urine endogenous metabolites, thereby laying a foundation for further study of the pharmacodynamical mechanism of GFW.

RASAL1 influences the proliferation and invasion of gastric cancer cells by regulating the RAS/ERK signaling pathway.

The aim of this study was to investigate the biological characteristics of the RASAL1 gene in a well-differentiated gastric cancer cell line MKN-28 and a poorly differentiated gastric cancer cell line BGC-823 cells, using RNA interference and gene transfection technology, respectively. MKN-28 cells were transfected with the shRNA of RASAL1 and BGC-823 cells were transfected with the pcDNA 3.1 plasmid vector containing RASAL1. RT-PCR and western blotting were then used to detect the expression of RASAL1 mRNA and protein. The activities of RAS and extracellular signal-regulated kinase 1/2 were analyzed by the pull-down method and western blotting. The proliferate capacity, apoptosis rate, invasive and migratory potentials of MKN-28 or BGC-823 cells were also measured by Cell Counting Kit-8 cell proliferation assay, propidium iodide/Annexin V staining coupled with flow cytometry, and transwell chamber assays, respectively. Measurement of RASAL1 mRNA and protein expression in two cells revealed successful transfection of the shRNA of RASAL1 and RASAL1-pcDNA3.1 plasmid into these two cells. Moreover, decreased expression of RASAL1 in MKN-28 cells resulted in increased expression of RAS-GTP and p-ERK1/2. Interestingly, decreased expression of RASAL1 inhibited apoptosis and facilitated cell proliferation, invasion and migration. The increased expression of RASAL1 in BGC-823 cells caused declined expression of RAS-GTP and p-ERK1/2, as well as promoted apoptosis and restrained cell proliferation, invasion and migration. The down-regulation of RASAL1 promoted the proliferation, invasion and migration of gastric cancer MKN-28 cells, and up-regulation of RASAL1 inhibited the proliferation, invasion and migration of BGC-823 gastric cancer cells by regulating the RAS/ERK signaling pathway. Thus, our results suggest that RASAL1 may play an important role as a tumor suppressor gene in gastric cancer.

[Multidrug resistance mechanisms in cell line HL-60/VCR].

BACKGROUND & OBJECTIVE: Drug resistance is a major factor in chemotherapeutic failure of leukemia. Multidrug resistant cell lines are the good models for investigating the mechanisms and reversal of acquired drug resistance. This study was designed to explore the multidrug resistance (MDR) mechanisms in cell line HL-60/VCR. METHODS: Flow cytometry and a panel of antibodies were used to analyze the expression of MDR proteins (P-gp, MRP, LRP, BCRP, GST-pi) and apoptosis-modulating proteins (bcl-2, bcl-x, bax, bad) in MDR cell line HL-60/VCR and drug sensitive cell line HL-60. RESULTS: The expression levels of MDR proteins (P-gp, MRP, BCRP, GST-pi) were (18.62, 1.19, 1.50, 1.32-flod) higher in HL-60/VCR than in HL-60, while the expression of LRP level was similar. The levels of apoptosis-modulating proteins(bcl-2, bcl-x, bad) were (2.48, 1.25, 1.08-fold) higher in HL-60/VCR than in HL-60, while the pro-apoptosis protein bax contrarily decreased in HL-60/VCR. CONCLUSION: Various MDR mechanisms were involved in multi-drug resistance HL-60/VCR cell line, which including increasing expression of drug-resistance protein (P-gp, MRP, BCRP, and GST-pi); the apoptosis-modulating proteins (bcl-2, bcl-x, bax, and bad) might take part in the mechanism of drug resistance.