Cell cycle block and apoptosis induction in a human melanoma cell line following treatment with 2-methoxyoestradiol: therapeutic implications?
Due to minimal success with non-surgical treatment options for melanoma, it is imperative that other compounds be tested for potential preventive/therapeutic use. We have tested the ability of the endogenous oestrogenic metabolite 2-methoxyestradiol (2-ME) to inhibit the growth of human melanoma cells in culture. 2-ME inhibited the growth of all the melanoma cells tested, without inhibiting the growth of non-tumorigenic cells. Microscopic observations showed that treated cells exhibit the characteristic features of apoptosis. Examination of the molecular mechanism in WM98-1 cells, using biochemical assays such as a modified TUNEL staining and DNA fragmentation, confirmed the induction of apoptosis following 2-ME treatment. Flow cytometry analysis showed that, following treatment, cells are arrested in the G(2)/M phase of the cell cycle. Western blot analysis of the G(2)/M regulatory proteins suggests that cdc2 is involved in the cell cycle block by Myt1 phosphorylation following 2-ME treatment. Furthermore, examination of the levels of apoptosis regulatory proteins showed that, while levels of p53, Bax and p21 are higher, that of anti-apoptotic Bcl-2 is undetectable in cells treated with 2-ME compared with untreated controls. Taken together these results have major implications for the use of 2-ME for melanoma management.
Ghosh
Rita
R
Department of Cancer Causation and Prevention, AMC Cancer Research Center and The University of Colorado Comprehensive Cancer Center, Denver, Colorado 80214, USA. ghoshr@amc.org
Ott
Ann M
AM
Seetharam
Divya
D
Slaga
Thomas J
TJ
Kumar
Addanki P
AP
D000077584:2-Methoxyestradiol; D017209:Apoptosis; D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D053938:DNA Fragmentation; D004958:Estradiol / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D005347:Fibroblasts / Q000378:metabolism; D005434:Flow Cytometry; D016195:G2 Phase; D006801:Humans; D020287:In Situ Nick-End Labeling; D007364:Intercalating Agents / Q000494:pharmacology; D008545:Melanoma / Q000188:drug therapy* / Q000473:pathology*; D008938:Mitosis; D008956:Models, Chemical; D010766:Phosphorylation; D011419:Propidium / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D007364:Intercalating Agents; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D011419:Propidium; D004958:Estradiol; D000077584:2-Methoxyestradiol