Ellipticine

Biochimica et biophysica acta, 2011, 1814(1):175-185.

Cytochrome P450- and peroxidase-mediated oxidation of anticancer alkaloid ellipticine dictates its anti-tumor efficiency.[Reference: WebLink]

An antineoplastic alkaloid Ellipticine is a prodrug, whose pharmacological efficiency is dependent on its cytochrome P450 (CYP)- and/or peroxidase-mediated activation in target tissues. The aim of this review was to summarize our knowledge on the molecular mechanisms of Ellipticine action in the cancer cells.
METHODS AND RESULTS:
The CYP-mediated Ellipticine metabolites 9-hydroxy- and 7-hydroxyEllipticine and the product of Ellipticine oxidation by peroxidases, the Ellipticine dimer, are the detoxication metabolites of this compound. In contrast, two carbenium ions, Ellipticine-13-ylium and Ellipticine-12-ylium, derived from two activation Ellipticine metabolites, 13-hydroxyEllipticine and 12-hydroxyEllipticine, generate two major deoxyguanosine adducts in DNA found in the human breast adenocarcinoma MCF-7 cells, leukemia HL-60 and CCRF-CEM cells, neuroblastoma IMR-32, UKF-NB-3, and UKF-NB-4 cells and glioblastoma U87MG cells in vitro and in rat breast carcinoma in vivo. Formation of these covalent DNA adducts by Ellipticine is the predominant mechanism of its cytotoxicity and anti-tumor activity to these cancer cell lines. Ellipticine is also an inducer of CYP1A, 1B1, and 3A4 enzymes in the cancer cells and/or in vivo in rats exposed to this compound, thus modulating its own pharmacological efficiencies.
CONCLUSIONS:
The study forms the basis to further predict the susceptibility of human cancers to Ellipticine and suggests that this alkaloid for treatment in combination with CYP and/or peroxidase gene transfer increasing the anticancer potential of this prodrug. It also suggests Ellipticine reactive metabolites 13-hydroxyEllipticine and 12-hydroxyEllipticine to be good candidates for targeting to tumors absent from the CYP and peroxidase activation enzymes.

Anti Cancer Drugs, 2005, 16(7):789-795.

The anti-proliferative inhibition of ellipticine in human breast mda-mb-231 cancer cells is through cell cycle arrest and apoptosis induction.[Reference: WebLink]

Ellipticine, a cytotoxic plant alkaloid, is known to inhibit topoisomerase II.
METHODS AND RESULTS:
Here we report the mechanism of apoptosis induction and cell cycle arrest by Ellipticine in human breast MDA-MB-231 cancer cells. Ellipticine treatment arrested MDA-MB-231 cells at the G2/M phase after 6 h of treatment. This effect was strongly associated with a concomitant decrease in the level of cyclin B1, Cdc25 and Cdc2, and increase in phospho-Cdc2 (Tyr15). In addition, Ellipticine also induced apoptosis in MDA-MB-231 cells, as determined by using both DNA fragmentation and Annexin-V staining assay. Ellipticine increased the expression of Bax, but decreased the level of Bcl-2, Bcl-XL and X-linked inhibitor of apoptosis protein (XIAP), and subsequently triggered the mitochondrial apoptotic pathway (release of cytochrome c, and activation of caspase-9 and -3). In addition, pre-treatment of cells with caspase-9 inhibitor inhibited Ellipticine-induced cell proliferation and apoptosis, indicating that caspase-9 activation was involved in MDA-MB-231 cell apoptosis induced by Ellipticine.
CONCLUSIONS:
Taken together, our study suggests that the inhibition of cell cycle progression signaling and initiation of the mitochondrial apoptotic system may participate in the anti-proliferative activity of Ellipticine in MDA-MB-231 cells.

Biomedical Papers of the Medical Faculty of the University Palacky Olomouc Czechoslovakia, 2006, 150(1):13-23.

Molecular mechanisms of antineoplastic action of an anticancer drug ellipticine.[Reference: WebLink]

Ellipticine is a potent antineoplastic agent exhibiting the multimodal mechanism of its action. This article reviews the mechanisms of predominant pharmacological and cytotoxic effects of Ellipticine and shows the results of our laboratories indicating a novel mechanism of its action. The prevalent mechanisms of Ellipticine antitumor, mutagenic and cytotoxic activities were suggested to be intercalation into DNA and inhibition of DNA topoisomerase II activity.
METHODS AND RESULTS:
We demonstrated a new mode of Ellipticine action, formation of covalent DNA adducts mediated by its oxidation with cytochromes P450 (CYP) and peroxidases. The article reports the molecular mechanism of Ellipticine oxidation by CYPs and identifies human and rat CYPs responsible for Ellipticine metabolic activation and detoxication. It also presents a role of peroxidases (i.e. myeloperoxidase, cyclooxygenases, lactoperoxidase) in Ellipticine oxidation leading to Ellipticine-DNA adducts. The 9-hydroxy- and 7-hydroxyEllipticine metabolites formed by CYPs and the major product of Ellipticine oxidation by peroxidases, the dimer, in which the two Ellipticine skeletons are connected via N(6) of the pyrrole ring of one Ellipticine molecule and C9 in the second one, are the detoxication metabolites. On the contrary, 13-hydroxy- and 12-hydroxyEllipticine, produced by Ellipticine oxidation with CYPs, the latter one formed also spontaneously from another CYP- and peroxidase-mediated metabolite, Ellipticine N(2)-oxide, are metabolites responsible for formation of two Ellipticine-derived deoxyguanosine adducts in DNA.
CONCLUSIONS:
The results reviewed here allow us to propose species, two carbenium ions, Ellipticine-13-ylium and Ellipticine-12-ylium, as reactive species generating two major DNA adducts seen in vivo in rats treated with Ellipticine. The study forms the basis to further predict the susceptibility of human cancers to Ellipticine.

Biochimica Et Biophysica Acta, 1974, 353(3):375-384.

Biochemical effects of ellipticine on leukemia L1210 cells.[Reference: WebLink]

METHODS AND RESULTS:
Ellipticine, a plant alkaloid, is cytotoxic to L1210 cells growing in culture and the growth inhibition cannot be prevented or reversed by the simultaneous addition of several metabolite mixtures. Furthermore, the inhibition cannot be eliminated by the removal of drug after a contact period of 15–120 min with cells and the phenomenon is dose related. Ellipticine significantly inhibits DNA, RNA and protein synthesis and as was found with the inhibition of cell growth, the inhibition was not reversible by removal of drug. Ellipticine shows no apparent effect on thymidine and uridine kinases nor on RNA polymerase, but it markedly inhibits DNA polymerase activity. With partially purified DNA polymerases of L1210 cells and of Micrococcus lysodeikticus, the inhibition by Ellipticine varied with the DNA templates used, e.g. salmon sperm DNA, poly[d(A-T) and poly(dG) · poly(dC). Ellipticine was found to interact with DNA, RNA and proteins.
CONCLUSIONS:
These results collectively suggest that the interaction with macromolecules is one of the primary determinants of the action of Ellipticine against L1210 leukemia.

Journal of Pharmacology & Experimental Therapeutics, 1976, 196(3):525-535.

A possible mechanism of ellipticine-induced hemolysis.[Reference: WebLink]

Ellipticine (E) [5,11-dimethyl-6H-pyrido-(4,3-b)-carbazole, NSC-71795] is an antineoplastic agent which is active against L1210 lymphocytic leukemia in mice.
METHODS AND RESULTS:
Preclinical toxicologic studies demonstrated hemolysis in dogs and monkeys following intravenous administration of 1.5 mg/kg. This finding prompted this investigation of the mechanism of hemolysis and a study of the various factors that might ameliorate this effect. Initial experiments demonstrated that human red blood cells were completely hemolyzed at an E concentration of 10(-3) M, while a concentration of 10(-4) M stabilized red blood cells against 150 mOsM NaCl. The extent of hemolysis correlated well with the surface activities, lipophilic properties and cellular uptake of E and some of its derivatives (7,10-dimethylEllipticine, isoEllipticine, 9-methoxyEllipticine and 11-demethylEllipticine). The greatest hemolysis occurred with 7,10-dimethylEllipticine and the least with 11-demethylEllipticine. The cellular uptake of E and its derivatives was linear over a wide concentration range and was not temperature-dependent. Hemolysis could be blocked by citrate, sodium ethylenediamine tetraacetate, oxytetracycline and [(+/-)-1,2-bis(3,5-dioxopiperazin-1-y1)propane]. The inhibition of E uptake by citrate appears to be a noncompetitive process and has a K1 of 1.9 X 10(-3) M.
CONCLUSIONS:
These data suggest that Ca++ might be involved in the hemolytic process and in the cellular uptake of E. The intravenous administration of Ellipticine to rhesus monkey caused severe hemolysis which could be prevented by simultaneous injection of citrate.