Experimental Study Of The Effect With 2-methoxyestradiol On The Myeloma Cells In Vitro

Objective: We studied the feasibility of 2-methoxyestradiol (2ME2) , an estrogen derivative on MM, which has special effect on various tumors in recent years, and explored its mechanism on MM. Methods: Cell viability was assessed by trypan blue assay, plasma cell labeling index (PCLI) was detected by BrdU assay, terminal-deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL)assay were used to determine apoptosis cells in situ. Synergistic effects of 2ME2 combined with other drugs were judged by King' S formula. The primary myeloma cells and hematopoietic precursors from 14 multiple myeloma patients were detected to determine apoptosis cells in situ by TUNEL assay. The influence of 2ME2 and arsenic trioxide (As₂O₃) were detected by RT-PCR at transcriptional level. We observed the changes of myeloma cell line CZ-1 and primary myeloma cells from 7 myeloma patients in morphology, expression of surface marker CD49e and quantification of light chain secretion in the supernatant. Differentiation induction effect of myeloma cell lines LP-1,CZ-1,NCI-H929 incubated with 2ME2 and xbp-1,Blimp-1,pax-5 phosporothioated antisense oligodeoxynucleotide (ASODN) were evaluated by cell morphology, CD49e flow cytometry (FCM) and quantitation of light chain secretion in the supernatant by ELISA. Results: 2ME2 could inhibit proliferation and induce apoptosis of myeloma cell lines. It has synergistic effects with dexamethasone As₂O₃ thalidomide and zoledronic acid. 2ME2 could electively induce apoptosis of primary myeloma cells from myeloma patients and has little apoptotic effect on granulocytic, erythrocytic and lymphocytic cells in the bone marrow. 2ME2 and As₂O₃ induced the myeloma cells CZ-1 apoptosis by different pathways individually. Lower concentrations of 2ME2 could induce differentiation of bone marrow CD₁₃₈⁺ cells from myeloma patients and myeloma cell lines. 2ME2 could induce cell differentiation on all three myeloma cell linesLP-1,CZ-1,NCI-H929. 2ME2 could up-regulate the XBP-1 mRNA expression in myeloma cell lines. Blimp-1 could help 2ME2 induce differentiation on myeloma cell lines by downregulating pax-5 mRNA and upregulating xbp-1 mRNA.