ABSTRACT
OBJECTIVE:To study 3D-QSAR of pyridine heterocyclic ring PI3K inhibitor as anti-renal cancer drug,and to provide reference for the design and R&D of new anti-renal cancer inhibitors. METHODS:The data of structure and active value (pIC50) of 30 pyridine heterocyclic ring PI3K inhibitors were collected. After Sybyl-X 1.1 software used for molecular superimposition, CoMFA and CoMSIA model were established to investigate three dimensional field, electrostatic field, hydrophobic field,hydrogen bond donor site and hydrogen bond acceptor field of PI3K inhibitor molecule. Sybyl-X 1.1 software was used for molecular docking,and the mechanism of PI3K inhibitor molecule and receptor target protein were analyzed. PyMOL V1.5 software was used to design new PI3K inhibitor molecules. The activity of inhibitor molecules was predicted with CoMFA and CoMSIA model. RESULTS:The cross validation coefficients of CoMFA and CoMSIA model were 0.617 and 0.601, fitting validation coefficients were 0.969 and 0.974,and external predictive correlation coefficients were 0.656 and 0.670, respectively. In CoMFA model, contributions of three dimensional field and electrostatic field were 56.2% and 43.8%respectively. In CoMSIA model,contributions of three dimensional field,electrostatic field,hydrophobic field,hydrogen bond donor site and hydrogen bond acceptor field were 41.0%,31.3%,21.1%,2.4%,4.2%. After molecular superimposition,small steric hindrance,strong positive and hydrophilic groups introduced nearby R1 group of common skeleton could help to enhance the activity of molecules. The results of molecular docking showed that PI3K inhibitor molecule formed three hydrogen bonds with the key amino acids ALA805,VAL882 and THR887 of receptor target protein,with the length of 1.84,1.99,1.99 ?. According to above information,6 new molecules were designed,among which predicted pIC50 of 2 molecules with higher activity were 3.211,3.247(CoMFA method)and 3.238,3.222(CoMSIA method). CONCLUSIONS:Established new CoMFA and CoMSIA model have good prediction ability and statistical stability. Contribution of three dimensional field is higher than that of electrostatic field,and the influence of hydrophobic field on molecular activity can not be ignored. Pyridine heterocyclic ring PI3K inhibitors have strong hydrogen bonding role with receptor target protein. 3D-QSAR can provide reference for the design,reconstruction and drug R&D of new PI3K inhibitor molecule.
ABSTRACT
An evaluation system including experiment preparation,experiment process,com-prehensive design of experiment,experiment skills and written exam was established in order to adapt to the experimental teaching reform in our school. Experimental preparation assessment was to evaluate‘preview and self-evaluation report’prepared and submitted by students. Experimental process assess-ment was to evaluate students' classroom performance and experiment reports. Assessment of compre-hensive design experiments was to evaluate the overall participation of students. Skill assessment was consisted of oral test and experiment operation test. Final written examination,mainly consisting of subjective questions,emphasized on student's flexible use of knowledge and ability to solve practical problems. The evaluation system of promoting student's learning and teacher's teaching through the examination not only fully arouse student's attention on experiment,but also make teachers more ob-jectively and really understand students' learning situation and the teaching effectiveness.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of hydroxycamptothecin (HCPT) on the proliferation, cell cycle and apoptosis of human lung carcinoma cell line A549.</p><p><b>METHODS</b>The growth of A549 cells exposed to HCPT was observed by staining with acridine orange/ethidium bromide dye. Agarose gel electrophoresis was performed to detect DNA fragmentation of the apoptotic cells. The cell cycle distribution of the exposed cells was analyzed using flow cytometry, and cell apoptosis was examined with annexin V-FITC/PI staining. RT-PCR was used to investigate Bcl-2 gene expression changes in the exposed cells.</p><p><b>RESULTS</b>Agarose gel electrophoresis of the DNA from HCPT-treated cells showed a DNA ladder, and typical apoptotic appearance of the exposed cells was observed under fluorescence microscope. Treatment of A549 cells with 1 µmol/L HCPT for 24 h resulted in a cell apoptosis rate of 18.11%, significantly higher than the rate in control cells (0.09%, P<0.05). The treatment also caused a significant reduction of Bcl-2 mRNA expression by 70% (P<0.05).</p><p><b>CONCLUSION</b>HCPT can significantly inhibit the proliferation, induce apoptosis, and down-regulate Bcl-2 gene expression in human lung carcinoma cell line A549, suggesting the involvement of Bcl-2 gene in the inhibitory effect of HCPT on A549 cells.</p>