Cancer: Prostate
Action: Growth arrest, autophagy
To investigate the mechanism of oridonin (ORI)-induced autophagy in prostate cancer PC-3 cells, PC-3 cells cultured in vitro were treated with ORI, and the inhibitory ratio of ORI on PC-3 cells was assayed by 3-4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. After ORI treatment, the proliferation of PC-3 cells was inhibited significantly in a concentration and time-dependent manner. SEM examination revealed cellular shrinkage and disappearance of surface microvilli in ORI-treated cells. Under TEM examination, the nuclei exhibited chromatin condensation and the appearance of a large number of autophagosomes with double-membrane structure in cytoplasm. AO staining showed the existence of AVOs. The expression of LC3 and the mRNA level of beclin 1 was increased by ORI. Furthermore, autophagy inhibitor 3-methyladenine reversed the increase of beclin 1 mRNA. The growth of PC-3 cells was inhibited, and autophagy was induced by ORI, indicating ORI may have a potential antitumor effect.
Cancer: Multiple myeloma
Action: Inhibits proliferation and induces apoptosis
This study was purposed to investigate the antitumor effect of oridonin on human multiple myeloma cell line U266 The results showed that the oridonin obviously inhibited the growth of U266 cell in dose-and time-dependent manners. As for morphological changes, characteristic apoptotic cells presented in U266 cells treated with 10 µmol/L oridonin for 24 hours. The apoptotic rate of U266 cells increased in dose and time dependent manners; after treatment of U266 cells with oridonin the mRNA levels of FGFR3, BCL2, CCND1 and MYC as well as the their protein levels decreased. Occasionally, the oridonin up-regulated the protein levels of P53 in the same manner. It is concluded that the oridonin can exert its anti-tumor effect by inhibiting proliferation and inducing apoptosis of U266 cell in dose dependent and time dependent manners, that maybe give the clues about new program of target therapy for multiple myeloma.
Source:
Cancer: Multiple myeloma
Action: Induces apoptosis and autophagy
Exposure to oridonin (1-64 μmol/L) inhibited the proliferation of RPMI8266 cells in a concentration-dependent manner with an IC(50) value of 6.74 μmol/L. Exposure to oridonin (7 μmol/L) simultaneously induced caspase 3-mediated apoptosis and Beclin 1-dependent autophagy of RPMI8266 cells. Both the apoptosis and autophagy were time-dependent, and apoptosis was the main effector pathway of cell death. Exposure to oridonin (7 μmol/L) increased intracellular ROS and reduced SIRT1 nuclear protein in a time-dependent manner.
Oridonin simultaneously induces apoptosis and autophagy of human multiple myeloma RPMI8266 cells via regulation of intracellular ROS generation and SIRT1 nuclear protein. The cytotoxicity of oridonin is mainly mediated through the apoptotic pathway, whereas the autophagy protects the cells from apoptosis.
Source
Cancer: Prostate, acute promyelocytic leukemia, breast, non-small-cell lung (NSCL), Ehrlich ascites, P388 lymphocytic leukemia, colorectal., ovarian, esphageal
Action: Chemoresistance, Ara-C, VP-16
Cancer cell arises in part through the acquisition of apoptotic resistance. Leukemia cells resistant to chemotherapy-induced apoptosis have been found to be sensitive to oridonin, a natural agent with potent anticancer activity. Weng et al., (2014) compared the response of human leukemia cells with oridonin and the antileukemia drugs Ara-C and VP-16. Compared with HL60 cells, K562 and K562/ADR cells displayed resistance to apoptosis stimulated by Ara-C and VP-16 but sensitivity to oridonin. Mechanistic investigations revealed that oridonin upregulated BIM-S by diminishing the expression of miR-17 and miR-20a, leading to mitochondria-dependent apoptosis. In contrast, neither Ara-C nor VP-16 could reduce miR-17 and miR-20a expression or could trigger BIM-S–mediated apoptosis.
Notably, silencing miR-17 or miR-20a expression by treatment with microRNA (miRNA; miR) inhibitors or oridonin restored sensitivity of K562 cells to VP-16. Synergistic effects of oridonin and VP-16 were documented in cultured cells as well as mouse tumor xenograft assays. Inhibiting miR-17 or miR-20a also augmented the proapoptotic activity of oridonin. Taken together, our results identify a miRNA-dependent mechanism underlying the anticancer effect of oridonin and provide a rationale for its combination with chemotherapy drugs in addressing chemoresistant leukemia cells.
Reference
Action: Induces apoptosis
Oridonin is a tetracycline diterpenoid isolated from the plant Rabdosia rubescens (RR) [(Hemsl.). Hara (Lamiaceae)] (dong ling cao) is a Chinese medicinal herb used widely in provinces including Henan. The aerial parts of RR and other species of the same genus has been reported to have the functions of clearing “heat” and “toxicity”, nourishing “yin”, removing “blood stasis”, and relieving swelling. RR has been used to treat stomach-ache, sore throat and cough.
Gastric Cancer, Esophageal Cancer, Liver Cancer, Prostate Cancer
RR and its extracts have been shown to be able to suppress disease progress, reduce tumor burden, alleviate syndrome and prolong survival in patients with gastric carcinoma, esophageal., liver and prostate cancers (Tang & Eisenbrand, 1992). Interestingly, other Isodon plants including Isodon japonicus Hara (IJ) and I. trichocarpus (IT) are also applied as home remedies for similar disorders in Japan and Korea.
Induces Apoptosis
These reports suggest that Isodon plants should have at least one essential anti-tumor component. In the 1970s, a bitter tetracycline diterpenoid compound, oridonin, was isolated from RR, IJ, and IT separately, and was shown to be a potent apoptosis inducer in a variety of cancer cells (Fujita et al., 1970; Fujita et al., 1976; Henan Medical Institute, 1978; Fujita et al., 1988).
Anti-cancer
There is currently research being undertaken regarding the relationship between the chemical structure/modifications and the molecular mechanisms underlying its anti-cancer activity, such as suppression of tumor proliferation and induction of tumor cell death, and the cell signal transduction in anti-cancer activity of oridonin (Zhang et al., 2010).
Prostate Cancer, Breast Cancer, NSCLC, Leukemia, Glioblastoma
Oridonin has been found to effectively inhibit the proliferation of a wide variety of cancer cells including those from prostate (LNCaP, DU145, PC3), breast (MCF-7, MDA-MB231), non-small-cell lung (NSCL) (NCI-H520, NCI-H460, NCI-H1299) cancers, acute promyelocytic leukemia (NB4), and glioblastoma multiforme (U118, U138).
Oridonin induced apoptosis and G0/G1 cell-cycle arrest in LNCaP prostate cancer cells. In addition, expression of p21waf1 was induced in a p53-dependent manner. Taken together, oridonin inhibited the proliferation of cancer cells via apoptosis and cell-cycle arrest with p53 playing a central role in several cancer types which express the wild-type p53 gene. Oridonin may be a novel, adjunctive therapy for a large variety of malignancies (Ikezoe et al., 2003).
Breast Cancer; Anti-metastatic
According to the flow cytometric analysis, oridonin suppressed MCF-7 cell growth by cell-cycle arrest at the G2/M phase and caused accumulation of MDA-MB-231 cells in the Sub-G1 phase. The induced apoptotic effect of oridonin was further confirmed by a morphologic characteristics assay and TUNEL assay. Meanwhile, oridonin significantly suppressed MDA-MB-231 cell migration and invasion, decreased MMP-2/MMP-9 activation and inhibited the expression of Integrin β1 and FAK. In conclusion, oridonin inhibited growth and induced apoptosis in breast cancer cells, which might be related to DNA damage and activation of intrinsic or extrinsic apoptotic pathways. Moreover, oridonin also inhibited tumor invasion and metastasis in vitro possibly via decreasing the expression of MMPs and regulating the Integrin β1/FAK pathway in MDA-MB-231 cells (Wang et al., 2013).
Gastric Cancer
The inhibitory effect of oridonin on gastric cancer HGC-27 cells was detected using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. After treated with oridonin (0, 1.25, 2.5, 5 and 10 µg/mL), HGC-27 cells were collected for anexin V-phycoerythrin and 7-amino-actinomycin D double staining and tested by flow cytometric analysis, and oridonin- induced apoptosis in HGC-27 cells was detected.
Oridonin significantly inhibited the proliferation of HGC-27 cells in a dose- and time-dependent manner. The inhibition rates of HGC-27 treated with four different concentrations of oridonin for 24 h (1.25, 2.5, 5 and 10 µg/mL) were 1.78% ± 0.36%, 4.96% ± 1.59%, 10.35% ± 2.76% and 41.6% ± 4.29%, respectively, which showed a significant difference (P < 0.05. Cells treated with oridonin showed typical apoptotic features with acridine orange/ethidium bromide staining. After treatment with oridonin, the cells became round, shrank, and developed small buds around the nuclear membrane while forming apoptotic bodies. However, the change in the release of LDH caused by necrosis was insignificant, suggesting that the major cause of oridonin-induced HGC-27 cell death was apoptosis. Flow cytometric analysis also revealed that oridonin induced significant apoptosis compared with the controls (P < 0.05).
Apoptosis of HGC-27 induced by oridonin may be associated with differential expression of Apaf-1, caspase-3 and cytochrome c, which are highly dependent upon the mitochondrial pathway (Sun et al., 2012).
Ehrlich Ascites, Leukemia
Oridonin has been found to also increase lifespan of mice bearing Ehrlich ascites or P388 lymphocytic leukemia. Oridonin triggered apoptosis in more than 50% of t(8;21) leukemic cells in vitro at concentration of 2 M or higher accompanied by degradation of AE oncoprotein, and showed significant anti-leukemia efficacies with low adverse effects in vivo. These data suggest possible beneficial effects for patients with t(8;21) acute myeloid leukemia (AML) (Zhou et al., 2007).
Prostate Cancer, Breast Cancer, Ovarian Cancer
Oridonin exhibited anti-proliferative activity toward all cancer cell lines tested, with an IC50 estimated by the MTT cell viability assay ranging from 5.8+/-2.3 to 11.72+/-4.8 microM. The increased incidence of apoptosis, identified by characteristic changes in cell morphology, was seen in tumor lines treated with oridonin. Notably, at concentrations that induced apoptosis among tumor cells, oridonin failed to induce apoptosis in cultures of normal human fibroblasts. Oridonin up-regulated p53 and Bax and down-regulated Bcl-2 expression in a dose-dependent manner and its absorption spectrum was measured in the presence and absence of double stranded (ds) DNA. Oridonin inhibits cancer cell growth in a cell-cycle specific manner and shifts the balance between pro- and anti-apoptotic proteins in favor of apoptosis. The present data suggest that further studies are warranted to assess the potential of oridonin in cancer prevention and/or treatment (Chen et al., 2005).
Ovarian Cancer Stem Cells; Chemotherapy Resistance
Oridonin was suggested to suppress ovarian CSCs as is reflected by down-regulation of the surface marker EpCAM. Unlike NSAIDS (non-steroid anti-inflammatory drugs), well documented clinical data for phyto-active compounds are lacking. In order to evaluate objectively the potential benefit of these types of compounds in the treatment of ovarian cancer, strategically designed, large scale studies are warranted (Chen et al., 2012).
Colorectal Cancer
Oridonin induced potent growth inhibition, cell-cycle arrest, apoptosis, senescence and colony-forming inhibition in three colorectal cancer cell lines in a dose-dependent manner in vitro. Daily i.p. injection of oridonin (6.25, 12.5 or 25 mg/kg) for 28 days significantly inhibited the growth of SW1116 s.c. xenografts in BABL/C nude mice.
Oridonin possesses potent in vitro and in vivo anti-colorectal cancer activities that correlated with induction of histone hyperacetylation and regulation of pathways critical for maintaining growth inhibition and cell-cycle arrest. Therefore, oridonin may represent a novel therapeutic option in colorectal cancer treatment as it has been shown to induce apoptosis and senescence of colon cancer cells in vitro and in vivo (Gao et al., 2010).
Colon Cancer; Apoptosis
Oridonin increased intracellular hydrogen peroxide levels and reduced the glutathione content in a dose-dependent manner. N-acetylcysteine, a reactive oxygen species scavenger, not only blocked the oridonin-induced increase in hydrogen peroxide and glutathione depletion, but also blocked apoptosis and senescence induced by oridonin.
Moreover, exogenous catalase could inhibit the increase in hydrogen peroxide and apoptosis induced by oridonin, but not the glutathione depletion and senescence. Furthermore, thioredoxin reductase (TrxR) activity was reduced by oridonin in vitro and in cells, which may cause the increase in hydrogen peroxide. In conclusion, the increase in hydrogen peroxide and glutathione depletion account for oridonin-induced apoptosis and senescence in colorectal cancer cells, and TrxR inhibition is involved in this process.
Given the importance of TrxR as a novel cancer target in colon cancer, oridonin would be a promising clinical candidate (Gao et al., 2012).
Prostate Cancer; Apoptosis
Oridonin (ORI) could inhibit the proliferation and induce apoptosis in various cancer cell lines. After ORI treatment, the proliferations of human prostate cancer (HPC) cell lines PC-3 and LNCaP were inhibited in a concentration and time-dependent manner. ORI induced cell-cycle arrest at the G2/M phase. Autophagy occurred before the onset of apoptosis and protected cancer cells in ORI-treated HPC cells. P21 was involved in ORI-induced autophagy and apoptosis (Li et al., 2012).
References
Henan Medical Institute, Henan Medical College, Yunnan Institute of Botany. (1978). Oridonin–a new anti-tumor subject. Chin Science Bull, 23:53–56.