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@#This study aimed to isolate and identify novel toxin peptides targeting voltage-gated sodium channels (VGSGs) from the venom of the Buthus martensii Karsch (BmK) scorpion. Using G50-gel filtration, HPLC, peptide fingerprinting and amino acid sequencing, a novel sodium channel modulator, BmK M2, was identified from BMK scorpion. BmK M2 is a relatively abundant long chain polypeptide toxin in BmK scorpion venom with a molecular weight of 7 235.59, consisting of 64 amino acids and 4 pairs of disulfide bonds.Sequence alignment showed that the amino acid sequence of BmK M2 had high sequence and structural similarity to that of the discovered sodium channel toxins of BmK M1, BmK M3 and BmK M9, etc.BmK M2 is a potential new sodium channel modulator.Electrophysiological results revealed that BmK M2 can significantly enhance the activation, delay the steady-state inactivation and closed-state inactivation of Nav1.7, but has no activity on Nav1.8.BmK M2 can be used as a novel peptide probe for the study of the structure and function of Nav1.7 and the development of drugs targeting Nav1.7.
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@#PAK1 plays an important role in the development of tumors. It is of great significance to screen and develop new PAK1 inhibitors as targeted drugs for cancer treatment. The traditional PAK1 inhibitor screening method has the problems of high cost and low efficiency. Computer virtual screening can reduce the cost of finding active lead compounds and improve the screening efficiency. In this study, a kind of PAK1 candidate compound was screened by computer assisted virtual screening combined with Z′lyteTM high flux kinase screen. In vitro enzyme activity screening showed that compound 18(K788)had good PAK1 inhibitory activity(inhibition rate was 42. 7%). Furtherly by MTT detection, it was found that K788 had significant PAK1 positive tumor killing activity, which was even better than the positive drug IPA-3. Flow cytometry and Western Blot showed that K788 could activate caspase apoptosis pathway and induce apoptosis of colon cancer cell DLD-1 by inhibiting PAK1 expression and activation. K788 has great potential for clinical development and application, and can be used as a PAK1 target for further research.
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A cDNA library was constructed from glands of wild Buthus martensii Karsch scorpion.A new sodium channel long-chain toxin BmkNaTx12 was identified by sequence alignment,and its full-length cDNA sequence was cloned.Sequence alignment showed that the sequence of BmkNaTx12 had high structural similarity with the β-toxin Cn12 from Mexican Centruroides noxius scorpion.The predicted structure of BmkNaTx12 was obtained by homologous model construction and the highest scoring model was selected.The protein structure was found to be stable at 300 ns by molecular dynamics optimization,and fluctuations at amino acids 20,35,and 52 are most like-ly due to the location of these amino acids in the loop region.Then,an expression system of recombinant BmkNaTx12-Fc fusion protein was constructed.The optimal expression time of recombinant protein was determined by Western blot and the fusion protein was successfully expressed in HEK293 cells.The purity of recombinant fusion protein which was obtained by protein A affinity chromatography was up to 95％ by SDS-PAGE gel electrophoresis and HPLC.In addition,the whole-cell patch-clamp assay results suggest that 1 μmoL/L BmkNaTx12-Fc can increase 20％ Nav1.7 peak current.These results laid a foundation for the further study of biological function.
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<p><b>OBJECTIVE</b>To study luteolin-induced non-small cell lung cancer cell line A549 apoptosis and the molecular mechanism for inhibiting its cycle arrest (G2 stage).</p><p><b>METHOD</b>MTT assay showed that luteolin had obvious inhibitory effect on A549 and indicated the half inhibition ratio (IC50). Cell cycle and apoptosis were detected by Hoechst 33258 nuclear staining assay, Annexin V-FITC/PI double staining and flow cytometry. Western blotting assay revealed changes in cycle and apoptosis-related proteins induced by luteolin. Possible molecular mechanism was suggested by Western blotting and immunocytochemistry.</p><p><b>RESULT</b>Luteolin had an obvious growth inhibitory effect on A549 cells, with IC50 of 45.2 micromol x L(-1) at 48 h. Flow cytometry showed A549 cells mainly arrested in G2 stage after being treated by luteolin, with low expressions in cyclin A, p-CDC2 and p-Rb. Hoechst 33258 nuclear staining and Annexin V-FITC/PI double staining showed that the luteolin treatment group showed a significant apoptosis rate than the non-treatment group. Western blotting found luteolin can increase phosphorylation of JNK and decrease that of NF-kappaKB (p65). Immunocytochemistry results revealed luteolin can inhibit TNF-alpha-stimulated p65 from nuclear translocation as a transcription factor and thus promoting cell apoptosis.</p><p><b>CONCLUSION</b>Luteolin can obviously induce apoptosis of human non-small cell lung cancer cell A549 possibly by increasing phosphorylation of JNK to activate mitochondria apoptosis pathway, while inhibiting NF-kappaB from nuclear translocation as a transcription factor.</p>
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Humanos , Anexina A5 , Metabolismo , Apoptosis , Western Blotting , Carcinoma de Pulmón de Células no Pequeñas , Metabolismo , Ciclo Celular , Línea Celular Tumoral , Luteolina , Farmacología , FN-kappa B , MetabolismoRESUMEN
Nanobody is a kind of antibody from camel, which misses light chain. Nanobody has the same antigen binding specificity and affinity as mAb. Moreover, because of its small molecular weight, high stability and easy preparation, nanobody has great value of biomedical applications. In this study, we successfully prepared highly pure antiEGFR nanobody in E.coli using genetic engineering techniques. Cell proliferation assay (CCK-8 assay) and migration experiments (cell scratch test and Transwell assay) indicated that the recombinant antiEGFRnano can significantly inhibit the proliferation and migration of endometrial cancer cells. These results provide a new way of thinking and methods for EGFR-targeted therapy of endometrial cancer.
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A recombinant plasmid pET28a-HBcAg-delta n was constructed, in which three mimic B-epitopes of HER family were inserted into the truncated HBc vector. The fusion protein expressed was purified and used to immunize BALB/c mice to induce antibody against the epitopes. Three mimic epitope genes were inserted into the sequences of amino acid residues 78 and 79 of HBcAg by overlap PCR. The PCR product was then cloned into pET28a to construct recombinant expression plasmid which was transformed to E. coli BL21 (DE3) and induced by IPTG. After purification, the fused protein designed HBHE was used to immunize BALB/c mice to detect humoral immunoresponse. The recombinant plasmid was successfully constructed by DNA sequencing analysis. A fusion protein with correct molecular mass was expressed and confirmed by SDS-PAGE. High titre antibody was elicited in the mice immunized with HBHE by indirect ELISA and Western blotting. The HBc particle vector containing three B-epitopes of HER family had been successfully prepared, purified and high titre antibody against HBHE was detected. All these data are helpful in further research of the broad-spectrum anti-tumour effect of combine polypeptide epi-position vaccine of EGFR and HER2.