Mechanism of growth inhibition effect of 3', 4', 5, 7-tetrahydroxyflavone on A549 cells / 中国中药杂志

<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>

Construction and immunological analysis of a combined multi-epitope vaccine against EGFR/HER2 / 药学学报

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.