Antiproliferation effects of oridonin on HPB-ALL cells and its mechanisms of action

Abstract

Oridonin, an ent-kaurane diterpenoid derived from the herbal Rabdosia rubescens, has been recently reported to have antitumor effects on a large variety of cancer cells. The present study was undertaken to investigate the in vitro antiproliferation and apoptosis inducing effects of oridonin on HPB-ALL cell lines and its mechanisms of action. HPB-ALL cells in culture medium in vitro were treated with different concentrations of oridonin (16-56 mmol/L). MTT assay was used to detect the cell growth inhibitory rate, and the cell viability was assessed by the trypan blue dye-exclusion method. Cell apoptosis and the mitochondrial membrane potential (Dym) were investigated by flow cytometry (FCM), Hoechst 33258 staining, and DNA fragmentation analysis. The expression of caspase-3 and different apoptosis modulators, including Fas and Bcl-2 family members, was analyzed by Western blotting. The results revealed that oridonin could significantly inhibit the growth of HPB-ALL cells and cause apoptosis, and the suppression was both timeand dose-dependent. After treatment with oridonin for 48 hr, the percentage of disruption of Dym gradually increased in a dose-dependent manner along with marked changes of cell apoptosis, and necrotic cells increased remarkably after the cells were treated with oridonin for 72 hr; Western blotting showed cleavage of the caspase-3 zymogen protein (32 kDa) with the appearance of its 20-kDa subunit when apoptosis occurred; expression of Bcl-2 and Bcl-XL was downregulated remarkably while expression of Bax and Bid was upregulated concurrently after the cells were treated with oridonin for 24 hr. Of note, the expressions of Fas and other Bcl-2 family members including Bak and Bad remained constant before and after apoptosis occurred. We therefore conclude that oridonin has significant antiproliferation effects on HPB-ALL cells by induction of apoptosis as well as directly causing cell necrosis and that oridonin-induced apoptosis on HPB-ALL cells is mainly related to the disruption of Dym and activation of caspase-3 as well as downregulation of anti-apoptotic protein Bcl-2, Bcl-XL, and upregulation of pro-apoptotic proteins Bax and Bid. The results indicate that oridonin may serve as a potential antileukemia reagent. Am.

Oridonin Confers Protection against Arsenic-Induced Toxicity through Activation of the Nrf2-Mediated Defensive Response

“…The anticancer activity of oridonin is thought to rely on its ability to inhibit cell growth, reduce angiogenesis, and enhance apoptosis (Chen et al 2005; Ikezoe et al 2003; Liu et al 2004, 2006; Meade-Tollin et al 2004; Zhang et al 2004a). Oridonin inhibits cell growth and induces apoptotic cell death in many cancer cell lines, including leukemia (NB4, HL-60, HPB-ALL, Kasumi-1), glioblastoma (U118, U138), melanoma (A375-S2), cervical carcinoma (HeLa), ovarian carcinoma (A2780, PTX10), prostate carcinoma (LNCap, Du145, PC3), breast carcinoma (MCF-7, MDA-MB231), murine fibrosarcoma (L929), and non–small-cell lung carcinoma (NCI-H520, NCI-H460, NCI-H1299) (Chen et al 2005; Ikezoe et al 2003; Liu et al 2004, 2006; Zhang et al 2004a). The reported doses needed for growth inhibition and apoptosis vary significantly among different groups using different cell lines, ranging from 0.5 μM (0.18 μg/mL) in Kasumi-1 cells to 56 μM (20.4 μg/mL) in HPB-ALL cells (Liu et al 2006; Zhou et al 2007b).…”

“…Oridonin induced p21 expression, resulting in cell cycle arrest in LNCaP and NCI-H520 cells (Ikezoe et al 2003). Oridonin activated the caspase 3–dependent apoptotic pathway through up-regulation of Bax and down-regulation of Bcl-2, which promotes release of cytochrome c (Chen et al 2005; Liu et al 2006). Inhibition of telomerase activity has been reported to be another mechanism that contributes to the anticancer function of oridonin (Liu et al 2004).…”

Down-regulation of androgen-receptor and PSA by phytochemicals

“…By flow cytometric analysis, the polyphenol fraction was demonstrated to induce G 0 /G 1 cell growth arrest and cell apoptosis in DU-145 and PC-3 triggered by caspase-3 activation (34,35). Since oridonin (36,37), baicalein, wogonin (38)(39)(40) and ISL (41) are known to stimulate caspase-3 activation, the apoptosis of LNCaP and DU-145 observed in Fig. 1 was likely caused by the same mechanism.…”

The inhibitory effect of oridonin on the growth of fifteen human cancer cell lines

“…Since then, studies have focused mainly on the anti-tumor effect of oridonin and its mode of action. Based on the studies of the anti-tumor pharmacodynamics of oridonin, in vitro tests have shown that oridonin has an inhibitory effect on such human cancer cell lines as: leukemias (HL60 [6,7] , K562 [8,9] , HPB-ALL [10] , NB4 [11] , Jurkat [12] ); esophageal cancers (CaEs-17 [13] ); gastric cancer (MGC80-3 [13] ); liver cancer (BEL-7402 [ 13,14] ); nasopharyngeal cancer (CNE [13,15] ); lung cancers (SPCA1 [16] , NCI-H520 [11] , N C I -H 4 6 0 [ 11 ] , N C I -H 1 2 9 9 [ 11 ] ) ; b r e a s t c a n c e r s ( M C F 7 [ 11 , 1 7 , 1 8 ] , MDA-MB231 [11] ); ovarian cancers (A2780 [18] , PTX10 [18] ); uterine cervix cancer (Hela [13,17,19] ) and prostatic cancers (LNCaP [11] , DU145 [11] , PC3 [11] ). Oridonin is a water-insoluble diterpene compound which is not easily absorbed when taken orally, and there is no preparation for intravenous infusion.…”