The study was aimed to investigate the mechanism of proliferation inhibition and apoptosis of MDS-RAEB MUTZ-1 cells induced by 2-methoxyestradiol (2-ME), the cell proliferation was determined by MTT assay, apoptosis rate was determined with annexinV-FITC/PI double staining and cell cycle was analyzed by flow cytometry (FCM) after MUTZ-1 cells were treated with different concentrations of 2-ME; the changes of morphologic features of MUTZ-1 cells were observed with Wright-Giemsa's staining; lactate dehydrogenase was determined by Beckman Counter; and agarose gel electrophoresis was used to verify whether 2-ME can induce apoptosis of MUTZ-1 cells. The results showed that 2-ME inhibited the proliferation of MUTZ-1 cells in a dose-and time-dependent manner and caused a sustained arrest at G(2)/M phase in MUTZ-1 cells; the typical apoptotic morphological features appeared in MUTZ-1 cells; the production of lactate dehydrogenase was up-regulated and the marked DNA ladder pattern of internucleosomal fragmentation was observed. It is concluded that the mechanism of proliferation inhibition and apoptosis of MUTZ-1 cells induced by 2-ME is probably related with the G(2)/M cell cycle arrest; 2-ME may be a potentially adjunctive anticancer drug useful to treat myelodysplastic syndrome.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Estradiol ; analogs & derivatives ; pharmacology ; Humans ; L-Lactate Dehydrogenase ; metabolism ; Myelodysplastic Syndromes ; pathology

This study was aimed to explore the effects and mechanisms of transplantation tolerance induced by "TBI + cyclophosphamide (CTX)" regimen combined with intra-bone marrow injection of allogenic BMCs. On day 0 C57BL/6 (H-2(b), B6) mice received sublethal dose of total body irradiation (TBI) ((60)Co gamma-ray) followed by intrabone marrow-bone marrow transplantation (IBM-BMT) of 3 x 10(7) cells/30 microl BMCs from BALB/c (H-2(d)) mice. The recipient mice were given CTX intraperitoneally 2 days after IBM-BMT. On day 7 skin grafting was performed and the skin survival was observed. The tolerance mechanism was investigated by mixed lymphocyte reaction (MLR), IL-2 reverse test, adoptive transfer assay in vitro. The results showed that the mean survival time (MST) of skin allografts in group treated with TBI + CTX + BMT was significantly longer, compared with that of other groups (P < 0.01). On day 90 after IBM-BMT, the phenotypic character of the recipient mice (black color) began to convert to that of the donor mice (white color). The MLR demonstrated that the immune responses of recipient mice were donor-specific tolerance. Suppressive activity in the spleen cells of tolerant B6 mice was observed in adoptive transfer assay in vitro. IL-2 reversal and the phenotypic conversion showed that the tolerance mechanisms were involved in clonal anergy and the development of chimerism. It is concluded that the nonmyeloablative regimen combined with IBM-BMT can induce a long-term tolerance, and the multiple mechanisms including clonal anergy, suppressor cells and chimerism were involved in transplantation immune tolerance.
Animals ; Bone Marrow Transplantation ; immunology ; methods ; Cyclophosphamide ; administration & dosage ; Female ; Immunosuppressive Agents ; Interleukin-2 ; administration & dosage ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Time Factors ; Transplantation Tolerance ; drug effects ; immunology ; Whole-Body Irradiation