Comparison of 2-methoxyestradiol and methotrexate effects on non-Hodgkin's B-cell lymphoma.
OBJECTIVE
Methotrexate (MTX) is the most commonly used chemotherapeutic agent to treat primary central nervous system lymphoma (PCNSL) and intraocular lymphoma (IOL). 2-methoxyestradiol (2ME2) is a potent antitumor and anti-angiogenesis agent which, unlike other cytotoxic drugs, has minimal toxicity. In this study, anti-proliferative, apoptotic, and cell-cycle effects of 2ME2 and MTX were compared to evaluate 2ME2 efficacy in human lymphoma cells, models for non-Hodgkin B cell lymphomas.


METHODS
The cells were cultured and incubated with varying concentrations of 2ME2 or MTX. A tetrazolium-based colorimetric assay was used to quantify the anti-proliferative effects of 2ME2 and MTX using a microplate reader. To detect apoptotic and cell cycle distribution changes induced by 2ME2 and MTX, the cells were stained with Annexin V-FITC and/or propidium iodide (PI) and analyzed by flow cytometry.


RESULTS
Lymphoma cell proliferation was inhibited by 50% at concentrations ranging from 0.4 to 1 microM for 2ME2 and 0.06 to 0.2 microM for MTX. Induction of apoptosis by 2ME2 and MTX was observed in the tested cells. 2ME2 was a G2/M-phase specific blocker whereas MTX was an S-phase specific blocker in cell cycle analyses. At 1 microM concentration, 2ME2 and MTX showed similar anti-proliferative effect on the lymphoma cell lines. In previously reported studies, for normal endothelial cells, 1 microM 2ME2 showed no appreciable toxicity, while MTX at this same concentration exhibited significant cytotoxicity. 2ME2 at a therapeutic target concentration of 1 mu M may be an effective and relatively non-toxic drug for the treatment of PCNSL with IOL.


CONCLUSIONS
Our study of the effect of 2ME2 and MTX on anti-proliferation, apoptosis, and cell cycling suggests that 2ME2 is a potential agent for treating PCNSL and IOL.
Park
Juyoung
J
Department of Mechanical Engineering, University of Cincinnati, Cincinnati, OH 45221-0072, USA.
Franco
Robert S
RS
Augsburger
James J
JJ
Banerjee
Rupak K
RK
D000077584:2-Methoxyestradiol; D017304:Annexin A5 / Q000378:metabolism; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006801:Humans; D016393:Lymphoma, B-Cell / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008727:Methotrexate / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured
D017304:Annexin A5; D000964:Antimetabolites, Antineoplastic; D004958:Estradiol; D000077584:2-Methoxyestradiol; D016650:Fluorescein-5-isothiocyanate; D008727:Methotrexate