Reversal of multidrug resistance and antitumor promoting activity of 3-oxo-6β-hydroxy-β-amyrin isolated from Pistacia integerrima

The bioactive triterpenoid 3-oxo-6-β-hydroxy-β-amyrin(1)has been isolated from multiple plant sources.In this study,chloroform fraction of Pistacia integerrima extract was processed for the isolation of the compound.The compound identity was confirmed by advanced spectroscopy technique.X-ray crystallography was applied for molecular structure confirmation.In addition,compound 1 was screen for its activity on reversal of MDR(multidrug resistance)mediated by P-gp(P-glycoprotein).This was accomplished by using rhodamine123 exclusion on multidrug-resistant human ABCB1 gene transfected mouse T-lymphoma cell line.Outcomes revealed that MDR reversing effect was comparable to verapamil as positive control in vitro.Treatment of TPA-induced tumor promotion with 3-oxo-6β-hydroxy-β-amyrin led to reduction in the applied anti-tumor promotion experiment.The chemo-preventive effect of 3-oxo-6β-hydroxy-β-amyrin was comparable to curcumin as positive control based on the reduction of immediate early tumor antigen expression.Molecular docking by applying Autodock Vina 1 and i-GEMDOCK v 2.1 tools indicated that compound 1 gives good docking results,as determined by their fitness score and specificity.Moreover,results showed that compound 1 isolated from Pistacia integerrima precisely attached to a region where co-crystallized ligand for receptor previously existed.Our findings may explain the use of Pistacia integerrima plant extracts as an anticancer agent in folk medicine.

GRP78 upregulation-induced increase in cisplatin sensitivity of SPCA1 lung cancer cells

Background Glucose regulated protein 78 （GRP78）, an endoplasmic reticulum （ER） chaperone, plays a critical role in chemotherapy resistance in a variety of cancers. In this study, we investigated the up-regulation of GRP78 induced by A23187 and its association with the chemotherapeutical sensibility to cisplatin in human lung cancer cell line SPCAI. Methods SPCA1 cells were pretreated with A23187 at different concentrations. The expression of GRP78 at the mRNA level was analyzed by RT-PCR; the expression of GRP78 at the protein level was determined by Western blotting and immunofluorescence assay. Cell survival was determined by MTT assay. Cell apoptosis was analyzed by flow cytometry. Results The expression of GRP78 at both the mRNA and protein levels was obviously induced by A23187 in SPCA1 cells, with an elevation of GRP78 by 2.1-fold at the mRNA level and by 3.8-fold at the protein level compared to the control. There was a dose-dependent response. Survival curve analysis demonstrated that A23187 induction caused a significant reduction of survival for the cells subjected to cisplatin treatment （P 〈0.05）. After treatment by cisplatin, the percentage of apoptotic cells in the A23187 pretreated group increased about three fold compared with the control group （（27.53!-4.32）% vs. （9.25＋3.64）%, P 〈0.05）. Conclusions A23187 treatment was fairly effective for the induction of GRP78 in SPCA1 cells at both the mRNA and protein levels. To a certain extent, GRP78 up-regulation by A23187 was associated with the enhancement of drug sensitivity to cisplatin in human luncl cancer cell line SPCAI.