ABSTRACT
Resistance to apoptosis is a characteristic of cancer. Curcumin has become a potential anticancer drug for its pro-apoptotic effects, but the underlying mechanisms remain unclear. Furthermore, the Notch3-p53 signaling axis serves an important role in cell fate. The present study was designed to investigate the antitumor effect of curcumin by the Notch3-p53 axis in mouse myeloma P3X63Ag8 cells. The effects of curcumin on the viability of P3X63Ag8 cells were evaluated using an MTT assay. Quantitative expression of the Notch3-p53 signaling axis-associated genes was measured by reverse transcription-quantitative polymerase chain reaction, and western blot analysis was used to investigate the expression of proteins. Additionally, flow cytometry was used to measure the ratio of apoptosis. The results demonstrated that curcumin could significantly inhibit cell viability. No significant pro-apoptotic effect was observed when the concentration of curcumin was <30 µM. At 30 µM, curcumin-treated cells exhibited an apoptotic phenomenon, and the ratio of late apoptosis increased with the concentration of curcumin, and reached 28.4 and 51.8% in the medium- and high-dose groups, respectively. Curcumin inhibited the expression of Notch3, while the middle- and high-dose groups promoted p53. The expression of Notch3-responsive genes Hes family BHLH transcription factor 1 and Hes-related family transcription factor with YRPW motif 1 were notably promoted. Curcumin treatment significantly downregulated B-cell lymphoma-2 (Bcl-2) at the mRNA and protein levels, but upregulated Bcl-2-associated X. These data indicated that curcumin exhibited antitumor effects in mouse myeloma cells with induction of apoptosis by affecting the Notch3-p53 signaling axis.
ABSTRACT
A new series of Mannich base of 1,3,4-oxadiazole derivatives possessing 1,4-benzodioxan (6a-6ae) were synthesized and characterized by (1)H NMR, ESI-MS and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction. All these novel compounds were screened for their in vitro antioxidant activity employing 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+)) and ferric reducing antioxidant power (FRAP) scavenging assays. Due to the combination of 1,4-benzodioxan, 1,3,4-oxadiazoles and substituted phenyl ring, most of them exhibited nice antioxidant activities. In all of these three assays mentioned above, compounds 6f and 6e showed significant radical scavenging ability comparable to the commonly used antioxidants, BHT and Trolox. Seven compounds with representative substituents or activities were selected for further assays in chemical simulation biological systems-inhibition of microsomal lipid peroxidation (LPO) and protection against 2,2'-azobis (2-amidinopropane hydrochloride) (AAPH) induced DNA strand breakage, in which, 6f and 6e were demonstrated to be of the most potent antioxidant activities.
