Cancer:
Glioblastoma, Lung, breast, colorectal, gastric, esophageal squamous carcinoma, prostate
Action:
Mitochondrial function, reactive oxygen species (ROS) generation.
Cytostatic, anti-inflammatory, chemo-prevention, COX-2 inhibitor, suppresses NF- κ B, induces IL-1 β , induces apoptosis
Ursolic acid, a pentacyclic triterpene acid found ubiquitously in the plant kingdom, including Rosmarinus officinalis (L.), Salvia officinalis (L.), Prunella vulgaris (L.), Psychotria serpens (L.) and Hyptis capitata (Jacq.). It has been shown to suppress the expression of several genes associated with tumorigenesis resulting in anti-inflammatory, anti-tumorigenic and chemo-sensitizing effects (Liu, 1995).
Glioblastoma Cancer
Ursolic acid, a natural pentacyclic triterpenic acid, possesses anticancer potential and diverse biological effects, but its correlation with glioblastoma multiforme cells and different modes of cell death is unclear. We studied the cellular actions of human GBM DBTRG-05MG cells after ursolic acid treatment and explored cell-selective killing effect of necrotic death as a cell fate.
Ursolic acid effectively reversed TMZ resistance and reduced DBTRG-05MG cell viability. Surprisingly, ursolic acid failed to stimulate the apoptotic and autophagic-related signaling networks. The necrotic death was characterized by annexin V/PI double-positive detection and release of HMGB1 and LDH. These ursolic acid-elicited responses were accompanied by ROS generation and glutathione depletion. Rapid mitochondrial dysfunction was paralleled by the preferential induction of necrosis, rather than apoptotic death. MPT is a phenomenon to provide the onset of mitochondrial depolarization during cellular necrosis. The opening of MPT pores that were mechanistically regulated by CypD, and ATP decline occurred in treated necrotic DBTRG-05MG cells. Cyclosporine A (an MPT pore inhibitor) prevented ursolic acid-provoked necrotic death and -involved key regulators.
The study by Lu et al., (2014) is the first to report that ursolic acid-modified mitochondrial function triggers defective death by necrosis in DBTRG-05MG cells rather than augmenting programmed death.
Gastric Cancer
Ursolic acid (UA) inhibits growth of BGC-803 cells in vitro in dose-dependent and time-dependent manner. Treated with UA in vivo, tumor cells can be arrested to G0/G1 stage. The apoptotic rate was significantly increased in tumor cells treated with UA both in vitro and in vivo. These results indicated that UA inhibits growth of tumor cells both in vitro and in vivo by decreasing proliferation of cells and inducing apoptosis (Wang et al., 2011).
Esophageal Squamous Carcinoma
The anti-neoplastic effects of combinations of anti-cancer drugs (5-fluorouracil, irinotecan and cisplatin) and triterpenes (ursolic acid, betulinic acid, oleanolic acid and a Japanese apricot extract (JAE) containing triterpenes) on esophageal squamous carcinoma cells were examined by the WST-8 (2-(2-methoxy- 4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) assay in vitro and by an animal model in vivo. Triterpenes and JAE showed additive and synergistic cytotoxic effects, respectively, on esophageal squamous carcinoma cells (YES-2 cells) by combinational use of 5-fluorouracil. JAE and 5-fluorouracil induced cell-cycle arrest at G2/M phase and at S phase, respectively, and caused apoptosis in YES-2 cells.
These results suggest that triterpenes, especially JAE, are effective supplements for enhancing the chemotherapeutic effect of 5-fluorouracil on esophageal cancer (Yamai et al., 2009).
COX-2 Inhibitor
Subbaramaiah et al. (2000) studied the effects of ursolic acid, a chemo-preventive agent, on the expression of cyclooxygenase-2 (COX-2). Treatment with ursolic acid suppressed phorbol 12-myristate 13-acetate (PMA)-mediated induction of COX-2 protein and synthesis of prostaglandin E2. Ursolic acid also suppressed the induction of COX-2 mRNA by PMA. Increased activator protein-1 activity and the binding of c-Jun to the cyclic AMP response element of the COX-2 promoter, effects were blocked by ursolic acid (Subbaramaiah et al., 2000).
Lung Cancer, Suppresses NF- κB
In terms of general anti-cancer mechanism, ursolic acid has also been found to suppress NF-κB activation induced by various carcinogens through the inhibition of the DNA binding of NF-κB. Ursolic acid also inhibits IκBα kinase and p65 phosphorylation (Shishodia et al., 2003). In particular, ursolic acid has been found to block cell-cycle progression and trigger apoptosis in lung cancer and may hence act as a chemoprevention agent for lung cancer (Hsu et al., 2004).
Breast Cancer
Ursolic acid is a potent inhibitor of MCF-7 cell proliferation. This triterpene exhibits both cytostatic and cytotoxic activity. It exerts an early cytostatic effect at G1 followed by cell death. Results suggest that alterations in cell-cycle phase redistribution of MCF-7 human breast cancer, by ursolic acid, may significantly influence MTT (colorimetric assays) reduction to formazan (Es-Saady et al., 1996).
Induces IL-1 β
Interleukin (IL)-1beta is a pro-inflammatory cytokine responsible for the onset of a broad range of diseases, such as inflammatory bowel disease and rheumatoid arthritis. It has recently been found that aggregated ursolic acid (UA), a triterpene carboxylic acid, is recognized by CD36 for generating reactive oxygen species (ROS) via NADPH oxidase (NOX) activation, thereby releasing IL-1beta protein from murine peritoneal macrophages (pMphi) in female ICR mice. In the present study, Ikeda et al. (2008) investigated the ability of UA to induce IL-1beta production in pMphi from 4 different strains of female mice as well as an established macrophage line. In addition, the different susceptibilities to UA-induced IL-1beta release were suggested to be correlated with the amount of superoxide anion (O2-) generated from the 5 different types of Mphi.
Notably, intracellular, but not extracellular, O2- generation was indicated to play a major role in UA-induced IL-1beta release. Together, these results indicate that the UA-induced IL-1beta release was strain-dependent, and the expression status of CD36 and gp91phox is strongly associated with inducibility.
Induces Apoptosis: Breast Cancer, Prostate Cancer
Ursolic acid (UA) induced apoptosis and modulated glucocorticoid receptor (GR) and Activator Protein-1 (AP-1) in MCF-7 breast cancer cells. UA is a GR modulator and may be considered as a potential anti-cancer agent in breast cancer (Kassi et al., 2009).
UA induces apoptosis via both extrinsic and intrinsic signaling pathways in cancer cells (Kwon et al., 2010). In PC-3 cells, UA inhibits proliferation by activating caspase-9 and JNK as well as FasL activation and Akt inhibition (Zhang et al., 2010). A significant proliferation inhibition and invasion suppression in both a dose- and time-dependent manner is observed in highly metastatic breast cancer MDA-MB-231 cells; this inhibition is related to the down-regulation of MMP2 and u-PA expression (Yeh et al., 2010).
Ursolic acid additionally stimulates the release of cytochrome C in HL-60 cells and breast cancer MCF-7 cells. The activation of caspase-3 in a cytochrome C-dependent manner induces apoptosis via the mitochondrial pathway (Qian et al., 2011).
Colorectal Cancer
Ursolic acid (UA) has strong anti-proliferative and apoptotic effects on human colon cancer HT-29 cells. UA dose-dependently decreased cell proliferation and induced apoptosis, accompanied by activation of caspase 3, 8 and 9. The effects may be mediated by alkaline sphingomyelinase activation (Andersson et al., 2003).
Ursolic acid (UA), using the colorectal cancer (CRC) mouse xenograft model and the HT-29 human colon carcinoma cell line, was evaluated for its efficacy against tumor growth in vivo and in vitro, and its molecular mechanisms were investigated. It was found that UA inhibits cancer growth without apparent toxicity. Furthermore, UA significantly suppresses the activation of several CRC-related signaling pathways and alters the expression of critical target genes. These molecular effects lead to the induction of apoptosis and inhibition of cellular proliferation.
These data demonstrate that UA possesses a broad range of anti-cancer activities due to its ability to affect multiple intracellular targets, suggesting that UA could be a novel multipotent therapeutic agent for cancer treatment (Lin et al., 2013).
Action: Anti-tumor, inhibits tumor cell migration and invasion
Ursolic acid (UA) is a sort of pentacyclic triterpenoid carboxylic acid purified from natural plant. UA has a series of biological effects such as sedative, anti-inflammatory, anti-bacterial, anti-diabetic, antiulcer, etc. It is discovered that UA has a broad-spectrum anti-tumor effect in recent years, which has attracted more and more scholars’ attention. This review explained anti-tumor actions of UA, including (1) the protection of cells’ DNA from different damages; (2) the anti-tumor cell proliferation by the inhibition of epidermal growth factor receptor mitogen-activated protein kinase signal or of FoxM1 transcription factors, respectively; (3) antiangiogenesis, (4) the immunological surveillance to tumors; (5) the inhibition of tumor cell migration and invasion; (6) the effect of UA on caspase, cytochromes C, nuclear factor kappa B, cyclooxygenase, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) or mammalian target of rapamycin signal to induce tumor cell apoptosis respectively, and etc. Moreover, UA has selective toxicity to tumor cells, basically no effect on normal cells.
Inhibition of Epidermal Growth Factor Receptor/ Mitogen-Activated Protein Kinase Pathway
Activation of mitogen-activated protein kinase (MAPK) allows cell excessive proliferation involved in the carcinogenic process (Park et al., 1999). Subfamilies of MAPK, metastasis.(24) Otherwise, UA suppresses the activation of NF-κB and down-regulation of the MMP-9 protein, which in turn contributes to its inhibitory effects on IL-1β or tumor necrosis factor α (TNF-α)-induced C6 glioma cell invasion (Huang et al., 2009).
U A suppresses inter cellular adhesion molecules-1 (ICAM-1) expression of non-small cell lung cancer (NSCLC) H3255, A549, Calu-6 cells, and significantly inhibits fibronectin expression in a concentration-dependent way. UA significantly suppresses the expression of MMP-9 and MMP-2 and inhibits protein kinase C activity in test cell lines, at the same time, UA reduces cell invasion in a concentration-dependent manner (Huang et al., 2011).
Cancer: Multiple myeloma
Action: Anti-inflammatory, down-regulates STAT3
When dealing with the multiple myeloma, by the way of activating the proto-oncogene-mediated c-Src, JAK1, JAK2, and ERKs, ursolic acid (UA) can not only inhibit the expression of IL-6-induced STAT3 but also downregulates the STAT3 by regulating gene products, such as cyclin D1, Bcl-2, Bcl-xL, surviving, Mcl-1 and VEGF. Above all, UA can inhibit the proliferation of multiple myeloma cells and induce apoptosis, to arrest cells at G1 phase and G0 phase of cell cycle (Pathak et al., 2007).
The essential oils of ginger (Zingiber officinale) and turmeric (Curcuma longa) contain a large variety of terpenoids, some of which possess anticancer, anti-ulcer, and antioxidant properties. Despite their importance, only four terpene synthases have been identified from the Zingiberaceae family: (+)-germacrene D synthase and (S)-β-bisabolene synthase from ginger rhizome, and α-humulene synthase and β-eudesmol synthase from shampoo ginger (Zingiber zerumbet) rhizome (Koo et al., 2012).
Cancer: Colorectal
Wong et al., have previously reported Signal Transducer and Activator of Transcription 3 (STAT3) to be constitutively activated in aldehyde dehydrogenase (ALDH)(+)/cluster of differentiation-133 (CD133)(+) colon cancer-initiating cells. In the present study they tested the efficacy of inhibiting STAT3 signaling in human colon cancer-initiating cells by ursolic acid (UA), which exists widely in fruits and herbs.
ALDH(+)/CD133(+) colon cancer-initiating cells. UA also reduced cell viability and inhibited tumor sphere formation of colon cancer-initiating cells, more potently than two other natural compounds, resveratrol and capsaicin. UA also inhibited the activation of STAT3 induced by interleukin-6 in DLD-1 colon cancer cells. Furthermore, daily administration of UA suppressed HCT116 tumor growth in mice in vivo.
Their results suggest STAT3 to be a target for colon cancer prevention. UA, a dietary agent, might offer an effective approach for colorectal carcinoma prevention by inhibiting persistently activated STAT3 in cancer stem cells.
References
Qian J, Li X, Guo GY, et al. (2011). Potent anti-tumor activity of emodin on CNE cells in vitro through apoptosis. J Zhejiang Sci-Tech Univ (Chin), 42:756-759
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