ABSTRACT
OBJECTIVE： To observe the inhibitory effects and possible mechanism of new small molecular kinase inhibitors Ibr-7 [Irutinil（Ibr） derivatives] on human pancreatic cancer Capan-2 cells. METHODS： Taking Capan-2 cells as objects， CCK-8 method was used to determine the proliferation of cells after treated with 1， 2， 4， 8 μmol/L Ibr/Ibr-7 for 48 h. The survival rates of cells were calculated. Sensitization effects of 1 μmol/L Ibr/Ibr-7 on different doses of gemcitabine/paclitaxel （0.062 5， 0.125， 0.25， 0.5， 1 μmol/L） were detected. Clone formation test was used to detect the situation of cell clone formation after treated with 1， 2， 4 μmol/L Ibr/Ibr-7 for 48 h. The number of cell colony formation was recorded. Flow cytometry or JC-1 method was used to detect the apoptosis of cells after treated with 2， 4， 8 μmol/L Ibr-7 for 24 or 16 h and the changes of mitochondrial transmembrane potential； total apoptotic rate and the percentage of mitochondrial membrane potential decrease were calculated. Western blotting was used to detect the expression of related apoptotic protein （PARP， Noxa， Bcl-2， Bax， Mcl-1， Bcl-xL）. RESULTS： After treated with 1， 2， 4， 8 μmol/L Ibr/Ibr-7 for 48 h， the survival rates of cells were decreased significantly； those of Ibr-7 groups were significantly lower than those of same-dose Ibr groups； IC50 of Ibr-7 was significantly lower than that of Ibr （P＜0.05 or P＜0.01）. After combined with Ibr/Ibr-7， the survival rate of cells was significantly lower than that of same-dose gemcitabine/paclitaxel alone group， and the Ibr-7 combination group was significantly lower than same-dose Ibr combination group （P＜0.05 or P＜0.01）. After treated with 2， 4 μmol/L Ibr and 1， 2， 4 μmol/L Ibr-7 for 48 h， the number of cell clone formation was decreased significantly， while Ibr-7 groups were significantly lower than same-dose Ibr groups （P＜0.01）. After treated with different doses of Ibr-7 for 24 or 16 h， total apoptosis rate of cells （2， 4， 8 μmol/L）， the proportion of cell mitochondrial membrane potential decrease （8 μmol/L）， the relative protein expression of Noxa （2， 4， 8 μmol/L） and Bax （8 μmol/L） were increased significantly， while the protein expression of PARP （8 μmol/L）， Bcl-2 （4 μmol/L）， Mcl-1 （2， 4， 8 μmol/L） were decreased significantly； above indexes （except for relative expression of PARP and Bcl-2） of 8 μmol/L Ibr-7 group were significantly better than same-dose Ibr group （P＜0.05 or P＜0.01）. There was no statistical significance in protein expression of Bcl-xL among those groups （P＞0.05）. CONCLUSIONS： Compared with Ibr， Ibr-7 has better inhibitory and apoptotic effects on human pancreatic cancer Capan-2 cells in vitro， and has stronger chemotherapeutic drug sensitization activity， the mechanism of which may be associated with reducing mitochondrial transmembrane potential， down-regulating the protein expression of PARP， Bcl-2 and Mcl-1 and up-regulating the protein expression of Noxa and Bax.
ABSTRACT
OBJECTIVE:To study the inhibitory effect and mechanism of Inula helenium ethyl acetate extract(IHE)on prolif-eration of human pancreatic cancer Capan-2 cells. METHODS:MTT was used to determine the cell proliferation inhibition rate af-ter treated by 0,0.5,1,2,4,8 μg/mL IHE;clone formation test was used to observe the effects of 0,1,2 μg/mL IHE treating for 1 week on cell clone formation;Hoechest 33342 staining was used to observe the changes of nuclear morphology after treated by 0,2,4 μg/mL IHE for 48 h;flow cytometry was used to detect the cell apoptosis rate after treated by 0,4,8,16 μg/mL IHE for 48 h;JC-1 staining was used to observe the changes of intracellular mitochondrial membrane potential after treated by 0,4,8, 16 μg/mL IHE for 24 h;Western blot was used to detect the expressions of mitochondrial apoptosis-related proteins Bcl-2,Bax, Mcl-1,p53 up-regulated modulator of apoptosis (PUMA),and polymerase (PARP) after treated by 0,4,8,16 μg/mL IHE for 48 h. RESULTS:2,4,8 μg/mL IHE had obvious inhibitory effect on cell proliferation,showing concentration-dependent relation-ship,with IC50 of 6.6 μg/mL;1,2 μg/mL IHE can obviously inhibit the clone formation of cells;4 μg/mL IHE can obviously cause cell nuclear condensation;8,16 μg/mL IHE can obviously promote the cell apoptosis,and the cell apoptosis rate reached 45.53% after treated by 16 μg/mL IHE for 48 h;16 μg/mL IHE treating for 24 h can cause the decrease of 82.47% cells'mito-chondrial membrane potential;8 μg/mL IHE can obviously down-regulate the protein expressions of Bcl-2,Mcl-1,PUMA and PARP,and 16 μg/mL IHE can obviously down-regulate the expressions of Mcl-1 and PUMA. CONCLUSIONS:IHE may show its inhibitory effect on proliferation of human pancreatic cancer Capan-2 cells by causing the decrease of mitochondrial mem-brane potential in cells and down-regulating the protein expres-sions of Mcl-1 and PUMA to cause cell apoptosis.