| In vitro: |
| J Ethnopharmacol . 2020 May 10;253:112504. | | Ergolide, a potent sesquiterpene lactone induces cell cycle arrest along with ROS-dependent apoptosis and potentiates vincristine cytotoxicity in ALL cell lines[Pubmed: 31904493] | | Ethnopharmacological relevance: Inula oculus christi belongs to the family of Asteraceae and it was traditionally wide used in treatment of kidney stones and urethra infection; besides, recently the potent sesquiterpene lactones isolated from inula species has gained increasing attention in cancer treatments. This study investigates the anti-cancer properties and underlying mechanism of ergolide isolated from Inula oculus christi against leukemic cell lines.
Methods: Viability, metabolic activity and proliferation evaluated using different index of MTT assay such as IC50 and GI50. Human erythrocytes were used to evaluate hemolytic activity. Flow-cytometry was used to detect and measure ROS level, and the induction of apoptosis and autophagy were evaluated using Annexin V/PI, Acridine Orange staining, respectively. Moreover, qRT-PCR was performed to examine the expression of a large cohort of crucial regulatory genes. Tunel assay was also carried out to assess morphologically ergolide effects.
Results: Ergolide did not exert ant cytotoxicity against non-tumorous cells and did not cause noticeable hemolysis. It also caused ROS production during early hours after treatment of cells which was then followed by cell cycle arrest in G0/G1 phase and autophagy induction. Using N-acetyl-L-cysteine (NAC), we found that ergolide could not increase ROS and induce autophagy and moreover repressed cell death, indicating that ergolide induce cell death through ROS-dependent manner by altering the expression of pro apoptotic related genes. Autophagy inhibition also potentiated ergolide-induced cell death. Furthermore, ergolide intensified vincristine cytotoxicity against acute lymphoblastic leukemia (ALL) cell lines revealed robust synergistic properties of ergolide with VCR.
Conclusion: Here we showed that ergolide could be considered as a potent natural compound against leukemic cells by inducing cell cycle arrest followed by dose-dependent cell death. Based on results, Autophagy response in a result of ROS accumulation acted as a survival pathway and blocking this pathway could noticeably increase ergolide cytotoxicity on ALL cell lines. | | Br J Pharmacol. 2001 Jun;133(4):503-512. | | Ergolide, sesquiterpene lactone from Inula britannica, inhibits inducible nitric oxide synthase and cyclo-oxygenase-2 expression in RAW 264.7 macrophages through the inactivation of NF-kappaB[Pubmed: 11399667] | | We investigated the mechanism of suppression of inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) by ergolide, sesquiterpene lactone from Inula britannica. iNOS activity in cell-free extract of LPS/IFN-gamma-stimulated RAW 264.7 macrophages was markedly attenuated by the treatment with ergolide. Its inhibitory effect on iNOS was paralleled by decrease in nitrite accumulation in culture medium of LPS/IFN-gamma-stimulated RAW 264.7 macrophages in a concentration-dependent manner. However, its inhibitory effect does not result from direct inhibition of the catalytic activity of NOS. Ergolide markedly decreased the production of prostaglandin E(2) (PGE(2)) in cell-free extract of LPS/IFN-gamma-stimulated RAW 264.7 macrophages in a concentration-dependent manner, without alteration of the catalytic activity of COX-2 itself. Ergolide decreased the level of iNOS and COX-2 protein, and iNOS mRNA caused by stimulation of LPS/IFN-gamma in a concentration-dependent manner, as measured by Western blot and Northern blot analysis, respectively. Ergolide inhibited nuclear factor-kappaB (NF-kappaB) activation, a transcription factor necessary for iNOS and COX-2 expression in response to LPS/IFN-gamma. This effect was accompanied by the parallel reduction of nuclear translocation of subunit p65 of NF-kappaB as well as IkappaB-alpha degradation. In addition, these effects were completely blocked by treatment of cysteine, indicating that this inhibitory effect of ergolide could be mediated by alkylation of NF-kappaB itself or an upstream molecule of NF-kappaB. Ergolide also directly inhibited the DNA-binding activity of active NF-kappaB in LPS/IFN-gamma-pretreated RAW 264.7 macrophages. These results demonstrate that the suppression of NF-kappaB activation by ergolide might be attributed to the inhibition of nuclear translocation of NF-kappaB resulted from blockade of the degradation of IkappaB and the direct modification of active NF-kappaB, leading to the suppression of the expression of iNOS and COX-2, which play important roles in inflammatory signalling pathway. | | J Pharm Pharmacol . 2005 Dec;57(12):1591-1597. | | Apoptotic potential of sesquiterpene lactone ergolide through the inhibition of NF-kappaB signaling pathway[Pubmed: 16354403] | | Treatment with ergolide, a sesquiterpene lactone from Inula britannica var chinensis, caused the induction of apoptosis in Jurkat T cells, which was confirmed by DNA fragmentation, caspase-3 activation and cleavage of poly(ADP-ribose) polymerase in response to ergolide. Furthermore, mitochondrial dysfunction appeared to be associated with ergolide-induced apoptosis, because Bax translocation and cytochrome c release were stimulated by ergolide. In parallel, the nuclear factor-kappaB (NF-kappaB) signaling pathway was significantly inhibited by ergolide, which was accompanied by down-regulation of cell survival molecules, such as X-chromosome-linked inhibitor of apoptosis and Bcl-2. In addition, the JNK signaling pathway was involved in ergolide-induced apoptosis. Collectively, our results identified a new mechanism for the anti-cancer property of ergolide, attributable to the induction of apoptosis through down-regulation of cell survival signal molecules resulting from inhibition of the NF-kappaB signaling pathway. | | J Pharm Pharmacol. 2007 Apr;59(4):561-566. | | Suppression of the NF-kappaB signalling pathway by ergolide, sesquiterpene lactone, in HeLa cells[Pubmed: 17430640] | | We have previously reported that ergolide, a sesquiterpene lactone isolated from Inula britannica, suppresses inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression by inhibiting nuclear factor-kappaB (NF-kappaB) in RAW 264.7 macrophages. In this study, we show that ergolide suppresses the DNA binding activity of NF-kappaB and nuclear translocation of NF-kappaB p65 subunit, leading to the inhibition of NF-kappaB-dependent gene transcription in 12-O-tetradecanoylphorbol 13acetate (TPA)-stimulated HeLa cells. We also show that ergolide decreases the degradation and phosphorylation of IkappaB, an inhibitory protein of NF-kappaB, and this effect is accompanied by a simultaneous reduction of IkappaB kinase (IKK) activity. However, ergolide does not inhibit in-vitro IKK activity directly, suggesting the possible involvement of upstream IKK kinases in the regulation of NF-kappaB activation. Furthermore, ergolide-mediated protein kinase Calpha (PKCalpha) inhibition is involved in reduction of NF-kappaB inhibition, as demonstrated by the observation that dominant negative PKCalpha, but not p44/42 MAPK and p38 MAPK, inhibits TPA-stimulated reporter gene expression. Taken together, our results suggest that ergolide suppresses NF-kappaB activation through the inhibition of PKCalpha-IKK activity, providing insight for PKCalpha as a molecular target for anti-inflammatory drugs. |
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