半枝莲新克罗烷型二萜成分逆转肿瘤多药耐药活性研究

Reversal of multi-drug resistance in HepG2/ADR cells by neo-clerodane diterpenoids from Scutellaria barbata

肿瘤细胞对化疗药物产生耐药性是肿瘤治疗失败的重要因素。其中,以P-糖蛋白(P-gp)为代表的ABC转运蛋白超家族异常表达引起的药物外排是产生多药耐药(MDR)的主要机制之一。本研究中,我们采用现代分离纯化方法,从半枝莲中分离并鉴定得到了6个已知的新克罗烷型二萜化合物:scutebarbatine Y(1)、scutebarbatine B(2)、suctebartine F(3)、clerdinin B(4)、scutellin A(5)、scutehennanine D(6)。其中,化合物4为首次从半枝莲中分离得到。体外逆转肿瘤多药耐药活性评价发现化合物1、2、3、6在20μM时,与阿霉素(Adr)联用可以逆转HepG2/Adr细胞对阿霉素的耐药性,逆转倍数(RI)范围为14.04~39.42;蛋白印迹分析结果表明,与HepG2敏感株相比,HepG2/Adr耐药细胞P-糖蛋白表达显著提高,可能是其产生耐药性的主要因素;荧光结果显示,该系列化合物能够明显促进阿霉素在HepG2/Adr细胞中的积累;但化合物不影响P-糖蛋白的表达。以上结果显示化合物1、2、3和6可能是通过抑制P-糖蛋白的外排功能来逆转肿瘤细胞多药耐药的。

Resistance of tumor cells to chemotherapy drugs is an important factor in the failure of tumor therapy.Among them,drug efflux caused by overexpression of P-glycoprotein(P-gp),a member of ATP-binding cassette transporter,is one of the main mechanisms of MDR.In this study,six known neo-clerodane diterpenoids were isolated from Scutellaria barbata.Using modern separation and purification methods,their structures were elucidated as scutebarbatine(1),scutebarbatine B(2),suctebartine F(3),clerdinin B(4),scutellin A(5)and scutehennanine D(6).Among them,Compound 4 was isolated from Scutellaria barbata for the first time.In addition,the reversal effect of compounds on the resistance to adriamycin(Adr)in HepG2/ADR cells was evaluated.The results showed that compound 1,2,3,6(20μM)had reversal activity when it was combined with adriamycin(Adr),with reversal index(RI)values from 14.04 to 39.42.Western blot analysis indicated that P-glycoprotein expression in HepG2/Adr cells was significantly higher than that in sensitive strains,which might be the main factor causing drug resistance.Fluorescence results showed that the compounds could significantly promote the accumulation of Adr in HepG2/Adr cells.However,the compounds did not affect the P-glycoprotein expression.These results indicated that compound 1,2,3 and 6 might reverse tumor multidrug resistance by inhibiting the efflux function of P-glycoprotein.