Discovery of a novel highly potent and low-toxic jatrophane derivative enhancing the P-glycoprotein-mediated doxorubicin sensitivity of MCF-7/ADR cells.

Use of novel modulators targeting P-glycoprotein (P-gp, ABCB1 transporter) is among the most accepted strategies for overcoming multidrug resistance in cancer chemotherapy. In the current study, we pursued our structure-activity relationship studies of jatrophane derivatives by structural modification of compound 1, a natural jatrophane isolated from Euphorbia. sororia A. Nine compounds exhibited higher reversal activity in P-gp/ABCB1-mediated MCF-7/ADR cells than verapamil (VRP). The cytotoxicity and doxorubicin (DOX) intracellular accumulation effects of jatrophane derivatives were assessed in normal HEK293T cells and DOX-resistant MCF-7/ADR cells. The most potent compound 17 merits multiple activities, including (1) high efficiency (EC50 = 182.17 ± 32.67 nM) in reversing P-gp-mediated resistance to DOX, low cytotoxicity, and a high therapeutic index; and (2) increasing the accumulation of Rhodamine123 (Rho123) and DOX in a dose-dependent manner compared to verapamil in MCF-7/ADR cells. Our results indicated that the reversal activity of 17 was due to the stimulation of the P-gp ATPase activity instead of the direct inhibition of P-gp protein expression. A docking study demonstrated that 17 has a high binding affinity toward the DOX recognition site of P-gp. This resulted in 17 enhancing the sensitivity of DOX to MCF-7/ADR cells by stimulating P-gp ATPase activity, increasing intracellular DOX and Rho123 concentrations, inhibiting the phosphoinositide 3-kinase/serine-threonine kinase mediated by DOX and further reducing the expression of P-gp. This study provides a promising P-gp inhibitor for reversing multidrug resistance and provides a basis for further research.

Jatrophane diterpenoids from Euphorbia microcarpa (prokh.) krylov with multidrug resistance modulating activity.

Eight undescribed jatrophane diterpenoids, namely euphomicrophane A-H, together with thirteen known diterpenes were isolated from the whole plant extracts of Euphorbia microcarpa (Prokh.) Krylov. Among them, euphomicrophane C and F were possessed the endo-type core structure that naturally rarely appeared. The structures of the purified undescribed compounds were established by extensive spectroscopic and spectrometric analysis, and the single-crystal X-ray diffraction analysis was used to determine the absolute configuration of euphomicrophane E, elusone A and euphorbesulin G. All the isolates were screened for their reversal abilities on P-glycoprotein-mediated multidrug resistant cancer cell line MCF-7/ADR. Compounds euphomicrophane G-H and 3ß,7ß,8α,9α,15ß-pentaacetoxy-5ß-benzoyloxyjatropha-6(17)-11E-dien-14-one were showed potential chemoreversal effect with reversal fold values 18.67, 17.15, and 16.76 at a concentration of 10.0 µM, being equal to or stronger than the positive drug verapamil (16.68).

Effects of Capparis spinosa Total Alkaloid on Notch Pathway in Mice with Systemic Sclerosis / 中国药房

OBJECTIVE： To study the effects of Capparis spinosa total alkaloid on Notch pathways related protein Notch2， Delta-like 3 （DLL3）， Jagged1 and Notch intracellular domain 1 （NICD1） in mice with systemic sclerosis （SSc）. METHODS： BALB/c mice were randomly divided into blank control group， model group， positive control group （penicillamine 125 mg/kg）， C. spinosa total alkaloid low-dose， medium-dose and high-dose groups （225， 450， 900 mg/kg）， with 16 mice in each group. Except for blank control group， other groups were given bleomycin subcutaneously for 4 weeks to induce SSc model. C. spinosa total alkaloid groups were given relevant dose of C. spinosa total alkaloid cream for external use. Positive control group was given relevant dose of penicillamine intragastrically. Blank control group and model groups were given cream matrix without drug， once a day， for consecutive 8 weeks. 4 h after last administration， the skin of the administration area of each group of mice was collected. mRNA expression of Notch2 and NICD1 was detected by real-time PCR； the content of DLL3 was measured by ELISA； the protein expression of Jagged1 in skin tissue was detected by immunohistochemstry. RESULTS： Compared with blank control group， mRNA expression of Notch2 and NICD1， DLL3 content， protein expression of Jagged1 were markedly increased， with statistical significance （P＜0.01）. Compared with model group， mRNA expression of NICD1， DLL3 content and protein expression of Jagged1 were decreased significantly in C. spinosa total alkaloid medium-dose and high-dose groups， positive control group， mRNA expression of Notch2 in skin tissue were decreased significantly in C. spinosa total alkaloid high-dose group and positive control group， with statistical significance （P＜0.05 or P＜0.01）. CONCLUSIONS： C. spinosa total alkaloid can inhibit the abnormal expression of Notch2， NICD1， DLL3 and Jagged1 in skin tissue of SSc model mice， and inhibit over activation of Notch pathway in SSc model mice.